G E O C

G E O C
GUIDE TO ENERGY EFFICIENCY OPPORTUNITIES IN
THE CANADIAN PLASTICS PROCESSING INDUSTRY
IN COLLABORATION WITH THE CANADIAN PLASTICS INDUSTRY ASSOCIATION
Canadian
Industry
Program for
Energy
Conservation
For more information or to receive additional copies of this publication, write to
Canadian Industry Program for Energy Conservation
c/o Natural Resources Canada
580 Booth Street, 18th Floor
Ottawa ON K1A 0E4
Tel.: 613-995-6839
Fax: 613-992-3161
E-mail: [email protected]
Web site: oee.nrcan.gc.ca/cipec
or
Canadian Plastics Industry Association
5915 Airport Road, Suite 712
Mississauga ON L4V 1T1
Tel.: 905-678-7748
Fax: 905-678-0774
Web site: www.cpia.ca
Photos courtesy of the Canadian Plastics Industry Association
ISBN 978-0-662-45754-1
Catalogue No. M144-151/2007E (print)
ISBN 978-0-662-46736-6
Catalogue No. M144-151/2007E-PDF (electronic)
© Her Majesty the Queen in Right of Canada, 2007
Library and Archives Canada Cataloguing in Publication
Guide to energy efficiency opportunities in the Canadian plastics processing industry.
Aussi disponible en français sous le titre : Guide sur les possibilités d'accroître l'efficacité
énergétique dans l'industrie de transformation des matières plastiques au Canada.
1. Plastics industry and trade—Energy consumption—Canada. 2. Plastics industry and
trade—Energy conservation—Canada. 3. Energy auditing—Canada.
I. Canadian Industry Program for Energy Conservation II. Canada. Natural Resources
Canada III. Canadian Plastics Industry Association
TJ163.5.S83B46 2007
Recycled Paper
338.4'766840682
C2007-980163-3
Natural Resources Canada’s Office of Energy Efficiency
Leading Canadians to Energy Efficiency at Home, at Work and on the Road
TABLE OF CONTENTS
i
1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. SECTOR PROFILE – CANADIAN PLASTICS PROCESSING SECTOR OVERVIEW . . . . . . . . . . . . . . . . 6
2.1 Sector Activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Industry Structure and Plant Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Current Economic Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.4 Resource Usage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4.1 Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.2 Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.3 Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5 Process Residuals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5.1 Air Residuals (Gases and Dust) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5.2 Wastewater and Liquid Wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5.3 Solid Waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.5.4 Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.6 Environmental Legislation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3. GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY . . . . . . . . . . . . 22
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.1.1 Greenhouse Gases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.1.2 Energy and Greenhouse Gas Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.1.3 Hydrofluorocarbon Emissions from Plastics Processing . . . . . . . . . . . . . . . 26
3.2 Opportunities for Reducing Greenhouse Gas Emissions. . . . . . . . . . . . . . . . . . . . . . 26
3.2.1 Canadian Industry Program for Energy Conservation . . . . . . . . . . . . . . . . 28
3.3 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4. GENERIC PROCESSES, PRODUCTS AND PRODUCT MARKETS . . . . . . . . . . . . . . . . . . . . . . . . 32
4.1 Generic Processes and Typical Products. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
4.2 Use of Plastic Products in Various Market Segments. . . . . . . . . . . . . . . . . . . . . . . . 33
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5. GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . 36
ii
5.1 Profile Extrusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
5.2 Thermoplastic Injection Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.3 Flat Film or Sheet Extrusion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.4 Blown-Film Extrusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.5 Blow Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.5.1 Extrusion Blow Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.5.2 Injection Blow Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.6 Compression Moulding of Thermoset Plastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.7 Foam Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.8 Auxiliary Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6. GENERIC IMPROVEMENT OPPORTUNITIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.1 Material Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.1.1 General Plant Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
6.1.2 Consumables and Maintenance Supplies . . . . . . . . . . . . . . . . . . . . . . . . . 59
6.1.3 Resin Conservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
6.2 Energy Conservation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.2.1 Specifying Energy-Efficient Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.2.2 Replacing Inefficient Equipment During Maintenance . . . . . . . . . . . . . . . 64
6.2.3 Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
6.2.4 Variable Speed Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
6.2.5 Hydraulic Pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.2.6 Hydraulic Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.2.7 Machine Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.2.8 Screws and Barrels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.2.9 Energy Management Practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3 Water Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
6.3.1 System Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
6.3.2 Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
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6.4 Auxiliary Systems and Facility Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.4.1 Dryers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
iii
6.4.2 Electrical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.4.3 Compressed-Air Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
6.4.4 Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
6.4.5 Process Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
6.4.6 Building Heating, Cooling and Ventilation . . . . . . . . . . . . . . . . . . . . . . . . 80
6.5 Emissions Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.5.1 Air Residuals – Gases and Dust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
6.5.2 Wastewater and Liquid Wastes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
6.5.3 Solid Waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.5.4 Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.5.5 Stormwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.6 Environmental Management Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
6.7 Case Studies in Resource Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
7. NEW AND EMERGING TECHNOLOGIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
7.1 Raw Material Developments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
7.2 Robotics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
7.3 All-Electric Injection-Moulding Machine. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
7.4 Microwave Drying. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
7.5 Granulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
7.6 Rapid Prototyping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
7.7 Gas-Assisted Injection Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
7.8 Co-Injection Moulding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
7.9 Toolmaking Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
7.10 Volatile Organic Compound (VOC) Control Technologies . . . . . . . . . . . . . . . . . . 94
7.11 Synchronous Torque Motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
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8. BENCHMARKING AND PERFORMANCE MONITORING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
iv
8.1 Raw Materials Usage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
8.2 Unit Electrical Energy Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
8.3 Unit Natural Gas Energy Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
8.4 Reduction in CO2 Emissions per Unit of Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
8.5 Unit Water Use. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
9. OTHER HELPFUL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
9.1 Miscellaneous Reference Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
9.2 Plastics Processing Industry Associations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
9.3 Industry Directories and Guides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
9.4 Environmental/Resource Audit Guidance Documents . . . . . . . . . . . . . . . . . . . . . 104
9.5 Pollution Prevention Guidance Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
9.6 Environmental Management Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
9.7 Web Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
9.8 Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
9.9 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
APPENDICES
Appendix I : ISO 14000 Standard Series . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Appendix II : Scope of Generic Plastics Manufacturing Processes Used in Canada . . . . 113
Appendix III : Selected Case Studies from Improving Energy Efficiency
at U.S. Plastics Manufacturing Plants . . . . . . . . . . . . . . . . . . . . . . . . . . 114
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1
INTRODUCTION
1
INTRODUCTION
1. INTRODUCTION
2
The plastics processing sector represents a large and growing sector of the Canadian
economy for which energy efficiency is a key issue. This sector has worked co-operatively
with provincial/territorial and federal government agencies to promote resource
conservation and to highlight opportunities to its stakeholders on how to improve energy
performance. An excellent example of this collaboration is the Guide to Energy Efficiency
Opportunities in the Canadian Plastics Processing Industry, which was prepared as a joint
effort between the Canadian Plastics Industry Association (CPIA) and the Canadian
Industry Program for Energy Conservation (CIPEC). This guide is intended to be a helpful
tool that can be used in conjunction with existing skills and knowledge among stakeholders
who share an interest in the plastics processing sector.
This guide has been updated from the original document produced in 1997. The new
version provides additional information and guidance in the area of greenhouse gas
emissions reduction. The purpose of this guide is to help plastics manufacturers identify
equipment, auxiliary systems and process improvements that will reduce production costs,
improve their competitive position, reduce pollution, and conserve energy, water and
other resources.
Since the publication of the original guide in 1997, Canada has introduced a national
strategy to reduce the country’s total greenhouse gas emission by 60 to 70 percent by
2050. While the Canadian plastics processing industry is not a major emitter of greenhouse gases, plastics processors can reduce costs and greenhouse gas emissions by conserving energy. Reducing greenhouse gases and how it relates to the plastics processing industry are described in Chapter 3 of this guide.
The primary users of this guide will be the executives in the plastics processing industry
who make equipment purchases, process improvements and maintenance decisions in a
competitive environment. However, the audience also includes all stakeholders in the
plastics manufacturing industry. Other readers who will benefit include owners, managers,
production supervisors, maintenance staff, employees, suppliers, designers, consultants and
industry associations. For readers who are not familiar with the industry and its technology,
Chapter 5, “Generic Processes and Auxiliary Systems Descriptions,” offers simplified
process descriptions and generic process diagrams.
The processes described herein are estimated to include over 90 percent of the market
activity in Canada. The significant thermoplastic processes that are discussed include
the following:
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•
profile extrusion;
•
thermoplastic-injection moulding;
ENERGY EFFICIENCY OPPORTUNITIES
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CANADIAN PLASTICS PROCESSING INDUSTRY
INTRODUCTION
•
flat film or sheet extrusion;
•
blown-film extrusion; and
•
blow moulding.
3
The two thermoset processes that are discussed include the following:
•
compression moulding of thermoset plastics; and
•
foam moulding.
In addition to these processes, auxiliary equipment and general plant systems common to
most plastics operations are also discussed. The plastics processing industry uses a broad
range of technologies, not all of which are discussed in this guide. A more complete listing
of processes may be found in Appendix III, which outlines the scope of generic plastic
manufacturing processes currently used in Canada.
An effective resource conservation and pollution prevention program requires the
following components:
1.
An understanding of current performance in terms of resource consumption
and efficiency.
2.
A detailed site-specific assessment to identify specific technical opportunities
for improvement.
3.
A management practices framework that will support and influence the
implementation of conservation opportunities.
4.
A continuous improvement approach to resource conservation activities.
As the level of technical analysis required for these components is beyond the scope of this
guide, only an introduction to these components is provided here.
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1
2
SECTOR PROFILE –
CANADIAN PLASTICS
PROCESSING SECTOR
OVERVIEW
2
SECTOR PROFILE – CANADIAN PLASTICS PROCESSING SECTOR OVERVIEW
2. SECTOR PROFILE – CANADIAN PLASTICS PROCESSING
SECTOR OVERVIEW
6
The “Sector Activities” section in this chapter focuses on the nature of Canada’s plastics
processing industry. The plastics processing industry is a significant part of a larger plastics
manufacturing sector. Canadian material suppliers manufacture resins from petrochemical
and other feedstocks. Canada also has several world-class manufacturers of processing
machinery and is a major producer of tooling for domestic and international plastics processors.
Canadian sales revenue in the plastics processing sector exceeded $38 billion in 2004. This
chapter discusses some of the major economic factors that affect Canadian processors’ ability
to compete in international markets. Trade balances and trends are also examined.
This chapter also discusses the use of resources and energy by the plastics processing industry
and provides a context for discussing savings opportunities.
The “Process Residuals” section discusses wastes and emissions that may be generated
from plastics processing. Environmental legislation relevant to the Canadian plastics
processing sector is also discussed in this section.
2.1 SECTOR ACTIVITIES
The plastics processing sector is characterized by many different processes and applications
that use an ever-increasing variety of raw materials. In addition to plants devoted to producing
custom products for third parties, many Canadian manufacturers have unique “captive”
plastics processing operations that manufacture finished goods for sale or components for
other end products. This diversity creates difficulty in assembling accurate statistics for the
industry. However, it is clear that the sector represents a significant portion of Canada’s
industrial activity and continues to experience a growth rate well in excess of the average
for all manufacturers.
In 2004, the Canadian plastics processing sector generated about $38.4 billion in shipments
and employed more than 146,000 people in approximately 3,800 companies. The major
markets served by the plastics industry are packaging, construction and transportation
(automotive). These segments account for 34, 26 and 18 percent, respectively, of the total
resin processed in Canada.
A brief and current profile of the plastic products processing sector is outlined in Table 2-1.
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SECTOR PROFILE – CANADIAN PLASTICS PROCESSING SECTOR OVERVIEW
Table 2-1 2004 Plastics Processing Industry Key Figures
7
Canada
Total Canadian Value Chain
$50.9 billion
Shipments by Processors
$38.4 billion
Shipments by Raw Material,
Machinery and Mould Suppliers
$12.5 billion
Total Processors Employment
146,880
Total Suppliers Employment
24,500
Total Sector Employment
171,380
Number of Plants
3,757
Resin Capacity (metric tonnes)
5.2 million
Plastics GDP* Growth vs. All Manufacturing
2.7 times faster
All Manufacturing GDP Growth
17% since 1999
Plastics Products GDP Growth
46.1% since 1999
* gross domestic product
Source: Canadian Plastics Industry Association (CPIA)
Following a brief period of decline in shipments in the early 1990s, which was due to
several macro-economic factors, Canadian plastic products shipments have increased every
year for the past 10 years, as shown in Figure 2-1. For the five-year period of 1995 to 1999,
Canadian plastic products shipments increased by an average of 7.6 percent per year;
and for the five-year period of 2000 to 2004, shipments increased by an average of
5.8 percent per year.
The plastics products industry has shown strong growth over the last decade with plastics
products gross domestic product (GDP) outgrowing the overall manufacturing sector
GDP growth by 2.7 times since 1999.
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SECTOR PROFILE – CANADIAN PLASTICS PROCESSING SECTOR OVERVIEW
Figure 2-1 Canadian Plastics Industry Shipments
8
25
5.8%/yr
20
7.6%/yr
15
Billion
2
10
5
0
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2.2 INDUSTRY STRUCTURE AND PLANT PROFILE
Although some consolidation and rationalization has taken place in the last few years,
Canada’s plastics processing industry continues to be characterized by a large number of
small- and medium-sized enterprises.
The average Canadian establishment employs approximately 40 people and has annual sales
of approximately $10 million. A number of Canadian plastics processors have emerged as
significant players in the North American market, each employing several hundred to over
a thousand people. Approximately two thirds of these larger companies are Canadian-owned.
Each of these firms has sales volumes in excess of several hundred million dollars, and several
have international affiliates or subsidiaries.
The structure of the industry showing the flow from raw materials to products is shown in
Figure 2-2. The custom and proprietary processors produce products that are sold to other
manufacturers or marketed directly by the producer. The captive processors incorporate
the plastic products manufactured as components into other products.
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Figure 2-2 Position of Processors within the Plastics Industry Structure
9
Value Multiplier
88%
Fuel
1
Crude Oil and
Natural Gas
Other Uses
Fertilizers
Lubricants
Petroleum
Solvents
Sealants
All other uses
1.9
Petrochemicals
6%
6%
Monomers
Ethylene
Styrene
Propylene
3.7
Synthetic Rubber
Tires
Plastic Resins
2%
Paints
Synthetic Fibres
Polyethylene
Polystyrene
PVC
ABS
Polypropylene
Clothing
Carpets
Drapery
Polyurethane
Polyester
Nylon
Acrylic
8.3
4%
15
Plastic Products
End-Use Products
Bathtubs
Insulation
Buttons
Meat trays
Cushions
Records, tapes
Egg cartons
Skis
Footballs
Wall coverings
Hangers
Brushes
Mattresses
Cups
Pipe fittings
Dish pans
Signs
Fishing rods
Toys
Garbage bags
Grocery bags
Bottles
Luggage
Combs
Milk jugs
Cutlery
Shower curtains
Eyeglasses
Telephones
Helmets
Wire and cable
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Automobiles
Houses
Shoes
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2.3 CURRENT ECONOMIC STATUS
10
Historically, many Canadian plastics manufacturers have been at a disadvantage to U.S.
producers with larger and more concentrated local markets. The smaller production runs
led to higher unit costs. For some bulky products, such as plastic piping, blown bottles or
beverage crates, high shipping costs have forced producers to set up operations to serve
regional markets. Most of Canada’s plastics processors are located close to their customers
in areas of high population density.
As a result of tariff reductions under the Free Trade Agreement (FTA) and North
American Free Trade Agreement (NAFTA), there has been some rationalization of end-use
industries. Certain traditional customers for plastics products have moved out of Canada to
the U.S. and Mexico as a result of the consolidation of production in a U.S.-owned firm
or the availability of lower Mexican assembly costs for labour-intensive products. NAFTA
had a modest incremental impact that resulted in some customers looking outside of
Canada for auto-related components and for lower value-added products. These losses have
been offset by, among other factors, the general strength of the Canadian automotive assembly
sector and the trend to just-in-time procurement that encourages parts manufacturers to
locate near assembly plants.
According to Industry Canada data on the plastics industry, the trade balance for Canadian
plastics products, which was a deficit for the first half of the 1990s and became a surplus in
1995, has grown to $2.65 billion by the year 2004, as shown in Figure 2-3.
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Figure 2-3 Canadian Trade Balance in Plastic Products (CAD$)
11
2.73
2.65
2004
2.50
2003
3.00
2.11
2.05
2001
2.00
2000
2.46
1.50
1.35
0.95
1998
0.86
0.50
1.00
1997
$ Billion
1.00
0.42
0.00
-1.10
-1.16
-1.15
1993
-1.00
1992
-0.50
-1.11
-1.37
-1.50
2002
1999
1996
1995
1994
1991
1990
-2.00
Source: CPIA
Export sales have risen in recent years (Figure 2-4) as the trade surplus increased by
20 percent since 2000.
Figure 2-4 Canadian Trade in Plastic Products with all Countries (CAD$)
10
9
8
7
$ Billion
6
5
4
3
2
1
0
2000
2001
2002
Total Exports
Total Imports
2003
2004
Trade Balance
Source: CPIA
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SECTOR PROFILE – CANADIAN PLASTICS PROCESSING SECTOR OVERVIEW
Trade with the U.S., which represents more than 90 percent of Canadian plastic products
exports, increased by approximately 15 percent over the past five years, while imports from
the U.S. have remained relatively constant with only a 1 percent increase (see Figure 2-5).
This trend has resulted in a trade surplus growth of 43 percent for the period between
2000 and 2004.
12
Figure 2-5 Canadian Trade in Plastic Products with the United States (CAD$)
10
9
8
7
6
$ Billion
2
5
4
3
2
1
0
2000
2001
United States Total Exports
2002
United States Total Imports
2003
2004
United States Trade Balance
Source: CPIA
Industry observers contend that Canadian plastic processors are well-positioned to grow
and compete on an international level in the coming years. The trade data show growth
in trade surplus with all countries, but when the trade surplus with the U.S. is removed,
Canada is in a trade deficit situation.
2.4 RESOURCE USAGE
The significant categories of resource usage by the plastics processing sector are discussed
below. The use of raw materials, usually the single-largest cost factor in a plastics processing
operation, is often difficult to track and manage effectively. Overall energy, water and solid
waste disposal costs are readily identified in utility and waste management bills. However,
many plants have little detailed knowledge of associated unit costs by specific machines
or processes.
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2.4.1 MATERIALS
13
2.4.1.1 Resins
For most manufacturers in this sector, raw materials are the single-largest operating cost.
In some operations with high throughputs, such as profile extrusion, it is not uncommon
for material purchases to exceed 70 percent of manufacturing expense. Typically, direct
labour constitutes 5 to 15 percent of the expense, while total energy costs are often less
than 5 percent.
Raw materials include resins, UV stabilizers, pigments, lubricants and other processing aids
and additives. This guide focuses primarily on firms that receive thermoplastic resins in pellet
form and does not specifically address operations that compound raw materials. Pellets are
routinely shipped in containers ranging from 25-kg bags to 500-kg gaylords, to even larger
truck or rail car shipments for high-volume producers. Improvements in the handling, processing
and recycling of raw materials represent a significant savings opportunity in this sector.
Numerous types of resins are used. Material suppliers constantly increase the range of
options available by developing new materials targeted at specific applications. The estimated
consumption of resins (by major type) in North America is provided in Figure 2-6.
Figure 2-6 Estimated North American Consumption of Major Plastic Resins
Styrenics
11%
ABS
2%
Polypropylene
15%
PVC
17%
Nylon
1%
Thermoplastic
Polyester
5%
Polyethylene
39%
Thermosets
10%
Sources: CPIA; SPI Committee on Resin Statistics as compiled by Association Services Group, LLC
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2.4.1.2 Other Supplies
14
Plastics processing facilities use a wide range of plant supplies related to equipment and
plant maintenance. Other supply categories related to specific processes and secondary
operations are also used.
Typical supply categories include the following:
•
Hydraulic oil: used to power process machinery. While the oil does not typically
need to be replaced frequently, losses through leaks and hose breakages may occur.
•
Tool room supplies: cutting oils, solvents and greases.
•
Processing supplies: some processors add pigments or dyes, and some moulding
operations also use mould releases.
•
Plant cleaning supplies: plant cleaning supplies include soaps, detergents and
absorbent materials for cleaning up oil spills.
•
Packaging and distribution materials: bags, gaylords and pallets. Shipments of
finished goods may be made in any or all of the following forms: cartons, plastic bags
and/or wooden crates.
2.4.2 ENERGY
Detailed estimates of the distribution of energy demand for typical extrusion, injection
moulding, blow moulding and blown-film plants were developed in 1993 for the former
Energy Mines and Resources Canada (now Natural Resources Canada) by Power Smart
Inc. of Vancouver. These data are summarized in Figures 2-7 to 2-9 for four generic
processes: 1) extrusion, 2) injection moulding, 3) blow moulding and 4) blown film.
The estimates illustrate the relative importance of energy demand by the processes and
auxiliary equipment as a proportion of the total facility demand. Furthermore, details of
the total process demand are provided to assist manufacturers in identifying priority areas
for energy-reduction projects.
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Figure 2-7 Estimate of Plant Energy Distribution from Selected Plastic Processes – Extrusion
Plant
10%
15
Barrel Heating
7%
Compressed Air 3%
Machine Cooling 4%
Process Chilling 19%
Auxiliary Equipment
42%
Granulator 6%
Extruder Drive
41%
Material Drying 7%
Material Handling 3%
Source: Power Smart (1993)
Figure 2-8 Estimate of Plant Energy Distribution from Selected Plastic Processes –
Injection Moulding
Barrel Heating
19%
Extruder Drive
18%
Compressed Air 2%
Machine Cooling 2%
Process Chilling 4%
Plant
10%
Auxiliary Equipment
17%
Granulator 2%
Material Drying 6%
Material Handling 1%
Mould Clamping
36%
Source: Power Smart (1993)
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Figure 2-9 Estimate of Plant Energy Distribution from Selected Plastics Processes –
Blow Moulding and Blown Film
16
Barrel Heating
6%
Plant
10%
Material Handling 4%
Granulator 6%
Finishing Equipment 7%
Material Drying 6%
Auxiliary Equipment
46%
Blown/Compressed Air 4%
Extruder Drive
38%
Process Cooling 15%
Machine Cooling 4%
Source: Power Smart (1993)
2.4.2.1 Electricity
Electricity is the main source of energy used by plastics processors. The main uses of
electricity include such applications as providing heat to extruder barrels through resistance
heaters and energizing extruder drives. Electricity is also used indirectly by providing the
power source for hydraulic, chilling, thermal-oil heating and compressed-air systems. Air
conditioning, ventilation and lighting for the facilities are still more uses of electricity.
Electrical costs account for approximately 3 to 4 percent of the production cost.
2.4.2.2 Natural Gas
Natural gas is used primarily for heating water and facilities. Other applications that can
use natural gas include rotational moulding, pellet dryers and internal combustion engines,
which can in turn power air compressors, hydraulic systems or electrical generators.
Natural gas costs account for approximately 1 to 2 percent of the production cost.
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2.4.3 WATER
17
Water is used for a variety of applications such as a cooling medium for profile extrusions
and process-machinery components such as moulds and extruder barrels. Water is also
used for cooling auxiliary equipment such as hydraulic and compressed-air systems. Water
use varies widely by plant and by process.
Some smaller processors use line water in a once-through application, discharging to sanitary
and/or storm sewers. Larger processors sometimes require significant volumes of cooling
water and also need to control water temperature. In such cases, closed-loop water-cooling
systems are preferred. Water can be recirculated and cooled using portable or permanent
chillers or cooling towers.
Most plastics processors recognize that it is cost-effective to install recycling systems for
process-cooling water. In addition to conserving the resource and saving money, the ability
to control water temperatures allows processors to improve product quality and throughput
efficiency. Environment Canada estimated in 1991 that 87 percent of water used by the
plastics processing sector was being recycled. Discussions with industry leaders indicate
that this number has probably increased since 1991, although no specific reference or
number was available.
2.5 PROCESS RESIDUALS
Plastic processors generate various types of wastes and releases to the environment that in
many cases can be reduced. Plastic materials, when processed under conditions specified by
the manufacturers, are relatively stable and do not present a significant risk to humans or
the environment. Cost savings may be achieved, however, by reducing waste and emissions,
especially by improving the management of raw material losses due to inefficiencies.
2.5.1 AIR RESIDUALS (GASES AND DUST)
Air emissions from plastics processing include volatile organic compounds (VOCs), dust
and carbon dioxide (a greenhouse gas). The following sections provide a brief description
of VOCs and dust emissions from plastics processing. Greenhouse gas emissions are covered
separately in Chapter 3.
2.5.1.1 Volatile Organic Compound (VOC) Emissions
VOCs are emitted from some plastics-manufacturing processes. VOCs contribute to the
generation of ground-level ozone – a major component of smog.
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The major source of VOC emissions in plastics processing results from the following:
18
•
degradation of resin;
•
blowing agents used for expanded foam products;
•
additives;
•
cleaning solvents; and
•
mould-releasing agents.
The four generic processes that account for approximately 60 percent of the VOC emissions
in the plastics processing sector are the following: 1) reinforced plastic and composite
products made from thermoset polyester resins, 2) extruded polyethylene [PE] foam,
3) expanded polystyrene [EPS] foam and 4) polyvinyl chloride [PVC].
A Plastics Processing Working Group was formed in 1997 in response to the Ontario’s
Smog Plan issued by the Ontario Ministry of Environment. The group’s purpose was to
address VOC emissions in the four processes identified above.
VOC emission estimates for each of the processes are presented in Table 2-2.
Table 2-2 Volatile Organic Compound (VOC) Emission Estimates
Resin Consumption
(tonnes processed
per year)
Process
VOC Emission
Estimates
(tonnes VOC/year)
1990
1997
% change
from
1990
1990
1997
% change
from
1990
15,085
14,860
-1.5%
1,347
1,143
-15%
PE Foam
2,600
3,700
+42%
149
355
+138%
EPS Foam
16,740
12,244
-27%
1,023
711
-30%
TBD
TBD
34,425
30,804
Composites
PVC
TOTAL
-10.5%
TBD
TBD
2,519
2,209
-12.3%
The following are highlights of the VOC emission reductions achieved between 1990 and
1997 for each process sub-group.
Composites: VOC emissions were reduced by an estimated 15 percent in 1997 from
1990, while resin consumption remained essentially the same during the period. This
reduction was achieved due to two main factors: First, a significant switch in process
technology from open moulding to closed moulding took place (as a proportion of resin
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consumption, the use of open moulding declined from 80 percent in 1990 to 70 percent
in 1997). With the move to closed moulding, VOC emissions have been reduced because
of the lower losses of styrene associated with closed-moulding operations. VOC emission
factors are estimated to be 5 percent for closed moulding as opposed to 22 percent for
open moulding based on the weight of available styrene. The second factor for the
achieved reduction in VOCs was due to a decrease in styrene content of supplied resin,
from 48 percent in 1990 to 45 percent in 1997.
19
PE Foam: VOC emissions in 1997 were more than double those in 1990. The main reason
is that the percentage of blowing agent used in blowing increased from 5.7 to 9.6 percent
of foam produced. This was due to the switch from CFCs and HCFCs to butane as a
blowing agent. As well, the increase in production rates of 42 percent also contributed
to the increased emissions.
EPS Foam: VOC emissions were reduced by an estimated 30 percent in 1997 from 1990.
The 30 percent decrease in emissions was largely due to a decline in Ontario resin consumption. This decline was the result of the loss of plants from Ontario. Another factor was a
decline in the VOC content of the supplied resin from 6.11 to 5.81 percent by weight.
PVC: Actual reductions achieved from 1990 have not been estimated.
For more detailed information on VOC emission reduction work in the Ontario plastics
processing industry, please refer to the Ontario’s Smog Plan – Progress Report of the Ontario
Plastic Processors Working Group (November 1999).
2.5.1.2 Dust
Some plastics processing operations are also known to emit airborne dust particles.
Material handling, blending and grinding operations have the potential to generate dust.
High levels of dust may create an explosion hazard. Efforts to minimize dust are also
encouraged to further reduce employees’ exposure to respiratory risk associated with
exposure to airborne particles.
2.5.2 WASTEWATER AND LIQUID WASTES
Non-contact cooling water may be used for machinery-, mould- or auxiliary-equipment
cooling prior to sanitary sewer system discharge. Potential contaminants include particulates
such as pellets, hydraulic or lubricating oils, and solvents.
Liquid wastes that require special handling and are commonly generated by the plastics
processing industry include used hydraulic oils, spent solvents and other chemicals.
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2.5.3 SOLID WASTE
20
The solid waste stream from plastics processing operations typically includes packaging
materials such as bags, gaylords and skids, purgings from machine start-ups, degraded
material and unsalvageable scrap. Pellets that have been spilled and raw materials that have
been contaminated by mixing or by foreign matter may also become solid waste destined
for disposal.
Other wastes not specifically related to the process include office waste, waste paper,
corrugated packaging, cafeteria/lunch room food wastes, bottles and cans, and
landscaping wastes.
2.5.4 NOISE
Hydraulic pumps, scrap grinders, sonic welders, and material handling and conveying
equipment are all considered to be common sources of objectionable noise. Excessive noise
levels can result in unpleasant working conditions. It may be necessary to control noise levels
to prevent exceeding the limits set out by the Occupational Health and Safety Regulations.
Plant noise that affects neighbouring residential, commercial or industrial operations is
regulated by municipal noise control by-laws. Noise sources that may exceed limits and
give rise to neighbourhood complaints can include material-handling techniques, such as
the emptying of tank trucks or rail cars.
2.6 ENVIRONMENTAL LEGISLATION
Many responsible processors seek to achieve environmental performance that would
exceed compliance with environmental legislation. A variety of environmental legislation
is of interest and could pertain directly to the plastics processing sector. The legislation is
intended to protect the environment from all potential discharges to the air, water and
land. Specific regulations vary by province/territory, but the key areas of relevant
legislation for plastic processors include the following:
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air emissions – particulates, odours, ozone-depleting substances
and greenhouse gases;
•
effluent discharges – direct discharges to receiving bodies and discharge to sewers;
•
solid wastes – hazardous and industrial wastes; and
•
recycling.
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3
GREENHOUSE GAS
EMISSIONS FROM THE
PLASTICS PROCESSING
INDUSTRY
3
GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY
3. GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING
INDUSTRY
22
3.1 INTRODUCTION
Climate change is an important global topic, and the connection between atmospheric
concentrations of greenhouse gases, air pollution, atmospheric warming and specific weather
events is very complex. The potential risks associated with climate change are significant
enough that reducing greenhouse gas emissions is necessary.
This chapter provides background information on the relationship between energy
consumption, plastics production and greenhouse gas emissions, and what is being done
to deal with this important issue.
3.1.1 GREENHOUSE GASES
There are six principal greenhouse gases. The list of gases and their global warming
potential are indicated in Table 3-1.
Table 3-1 Greenhouse Gases
Greenhouse Gas
Abbreviation
Global Warming
Multiplier
Carbon dioxide
CO2
1
Methane
CH4
21
Nitrous oxide
N2O
310
Hydrofluorocarbons
HFCs
140–11,700
Perfluorocarbons
PFCs
6,500–9,200
SF6
23,900
Sulphur hexafluoride
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GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY
Greenhouse gas emissions are generated primarily as a result of energy consumption in the
plastics processing industry. There are minor quantities of HFCs emitted from the extruded
polystyrene and polyurethane foam-production process that will be discussed in a later section.
23
3.1.2 ENERGY AND GREENHOUSE GAS EMISSIONS
As mentioned above, greenhouse gas emissions are generated primarily as a result of energy
consumption in the plastics processing industry. The significant growth that the plastics
processing sector has experienced over the past decade has been accompanied by a growth
in energy consumption and associated greenhouse gas emissions. The Canadian Plastics
Industry Association, in cooperation with the Canadian Industry Program for Energy
Conservation (CIPEC), commissioned a Review of Energy Consumption and Related
Data (CIEEDAC, 2005), which highlights some of the difficulties in obtaining an accurate
representation of energy efficiency and emissions intensity of the Canadian plastics industry.
The major limitations to the data for the plastics industry are related to the differences in
sector population definition and the fact that production data are not readily available for
the sector to estimate energy performance trends. In spite of these limitations, the
following section provides a brief summary of the energy consumption trends for the
sector and an estimate of the energy efficiency performance of the sector for the period
from 1999 to 2004.
The two primary forms of energy used by the plastics processing industry are electricity
and natural gas. As indicated in Chapter 2, electricity is the main source of energy with
electrical costs accounting for 3 to 4 percent of the cost of production. Electricity is used
to provide heat to extruder barrels and to energize extruder drives. Electricity is also used
as a power source for hydraulics, chilling, heating and compressed air, and for providing
ventilation, air conditioning and lighting for the building. Natural gas costs can account
for approximately 1 to 2 percent of the cost of production. Natural gas is primarily used
for heating water and facilities, but can be used in many other applications within the
plastics-manufacturing process.
The total energy consumed by the Canadian plastics processing sector (as defined by
NAICS 3261) for the period from 1999 to 2004 is presented in Figure 3-1. The sector
gross domestic product (GDP) is also shown in Figure 3-1, which gives an indication of
the growth of the sector for the same period.
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Figure 3-1 Canadian Plastics Processing Sector Energy Consumption and GDP
24
30,000
9,000
8,000
25,000
7,000
5,000
15,000
4,000
3,000
Energy (TJ)
20,000
6,000
GDP ($ millions)
3
10,000
2,000
5,000
1,000
0
0
1999
2000
2001
2002
Total Energy
2003
2004
GDP
For the six-year period 1999–2004, the total energy consumed in the plastics products
industry increased 36 percent from 19,950 terajoules to 27,050 terajoules. For that same
period, GDP increased by 46 percent from $5.7 billion to $8.4 billion.
3.1.2.1 Greenhouse Gas Emissions Performance
Greenhouse gas emissions are considered as either direct emissions, as a result of
combustion of fuel at the plastics processing facility, or indirect emissions, as a result of
fossil-fuel combustion required to generate the electricity used by the plastics processing
facility. The factors used to estimate the emissions of CO2, CH4 and N2O resulting from
the combustion of natural gas (which represents approximately 85 percent of the plastics
product sector direct emissions) are shown in Table 3-2.
Table 3-2 Emission Factors from Natural Gas Combustion
Gas
Emission Factor (g/m3 fuel)
CO2
1880
CH4
0.0048
N2O
0.02
The CH4 and N2O emissions are minor compared to the CO2 emissions. The convention
of reporting greenhouse gas emissions on a CO2-equivalent basis will be used throughout
this report.
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GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY
Canadian plastics products processors should be concerned with the greenhouse gas emissions
performance of their operations, or the emissions per unit of production. On a Canadian
aggregate basis, there are no data available to measure the production levels annually, but,
as shown in Figure 3-1, the GDP can be used as an approximation. This is useful to get a
sense of the performance trend, but could be skewed by disproportionate increases in price
of products and other monetary factors.
25
By improving energy efficiency, plastics processors can reduce both direct emissions (from
consuming fossil fuels on site) and indirect emissions (associated with electricity generation
off-site). Indirect-emissions intensity will be influenced by the form of electrical generation
(i.e. thermal versus hydropower), which will vary significantly between provinces/territories,
and will not be within the control of the plastics processors. The direct emissions are most
relevant and controllable by the plastics processing facilities. The trend in direct emission
performance, as a function of GDP, is presented in Figure 3-2 based on data from the
Canadian Industrial Energy End-Use Data Analysis Centre (CIEEDAC) for Canada, for
the 1999–2004 period.
Figure 3-2 Canadian Plastics Products Industry Greenhouse Gas Emissions as Percentage of GDP –
Plastic and Rubber Products Manufacturing
0.110
0.105
kt C02e/$GDP
0.100
0.095
0.090
0.085
0.080
0.075
1999
2000
2001
2002
2003
2004
Year
As shown in Figure 3-2, direct greenhouse gas emissions as a percentage of GDP have
been stable for the past three years but, overall, have decreased by 15 percent since 1999.
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3.1.3 HYDROFLUOROCARBON EMISSIONS FROM
PLASTICS PROCESSING
26
Hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC) are used as blowing
agents in the production of extruded-polystyrene and polyurethane foams. The use of HFCs
in plastics processing globally is currently on the rise as the greenhouse gas HFC is used as
a replacement for the ozone-depleting HCFCs. The use of HCFCs or HFCs in the Ontario
plastics processing sector is minor, with only three companies reporting HCFC emissions
in the National Pollutant Release Inventory (NPRI) database (companies are not required
to report HFCs to the NPRI program).
Specific data on HFC emissions are not available and much of the work in evaluating alternatives
to the use of these compounds is proprietary. Canada’s Greenhouse Gas Inventory estimates
that 10,000 kilotonnes of CO2-equivalent HFCs were emitted from foam blowing in Canada
in 1997. There are no data available to estimate the HFC emissions from Canadian plastics
processing, and therefore it is not possible to determine if HFC emissions in Canada are
increasing or decreasing. In discussions with one Canadian plastics processor, it was reported
that it had successfully eliminated the use of HCFCs and HFCs from its production.
Further references for more information on HFC use in plastics processing are provided
in Chapter 9.
3.2 OPPORTUNITIES FOR REDUCING GREENHOUSE
GAS EMISSIONS
Direct emissions from plastics processing in Canada are small (less than 1 percent) in relation
to discharges from other manufacturing activities in Canada. Direct emissions have increased
by 8 percent since 1999, but emission intensity has decreased by 15 percent as shown in
Figure 3-2.
Both direct and indirect greenhouse gas emissions can be reduced through ongoing
improvements in energy efficiency at any given plastic processing facility. Investments in
energy-efficient technologies and capital upgrades must make financial sense if plastics
processors are expected to make such investments.
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CANADIAN PLASTICS PROCESSING INDUSTRY
GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY
The rate of investment in energy efficiency is determined to a large degree by the following
two factors:
1.
Age, capability and depreciated value of the existing capital stock – the average
service life of machinery and equipment for the plastics product industry is 13 years.
It is not uncommon for small operations to be using equipment in the 20- to 30-year
age range.
2.
Rate of return expected on investment in new technology and equipment – currently,
the amount of investment generated from energy savings alone falls short of covering
the capital costs of replacing existing equipment with highly energy-efficient equipment.
27
Information on energy efficiency programs and resource material is provided in Chapter 9.
Plastics Help Reduce Greenhouse Gas Emissions from Automobiles
As automakers continue to look for ways to reduce vehicle weight, to reduce costs and
to improve fuel economy, a related benefit is a reduction in greenhouse gas emissions
per kilometre driven. Here are just a few examples:
•
The 2001 Chevrolet Silverado used reinforced-reaction injection-moulded (RRIM)
plastic fenders and a structural-reaction injection-moulded (SRIM) composite cargo
box to make the truck’s total weight 25 kilograms lighter than
with conventional steel components.
•
The 2001 Chevrolet full-size and heavy-duty pickups have RRIM rear fenders saving
30 kilograms of weight.
•
DaimlerChrysler and Ford Motor Co. introduced plastic rear bumpers on selected
models. This was the first non-metallic rear bumper in its class, and the bumper
system is 41 percent lighter than its steel counterpart.
Greenhouse gas emissions from passenger automobiles and light trucks continue to grow, as
more vehicles are driven more kilometres. With more than 31,000 kilotonnes of CO2 emissions
from this sector, representing approximately 16 percent of Ontario’s total greenhouse gas
emissions, every incremental reduction will have an impact.
Reference:
www.findarticles.com/m3012/10_180/0/p1/article.jhtml
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3
3
GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY
3.2.1 CANADIAN INDUSTRY PROGRAM FOR
ENERGY CONSERVATION
28
The Canadian Industry Program for Energy Conservation (CIPEC) is a national program
that “promotes effective voluntary action that reduces industrial energy use per unit of
production, thereby improving economic performance while participating in meeting
Canada’s climate change objectives.” CIPEC is composed of sectoral task forces, each
of which represents companies engaged in similar industrial activities.
CIPEC works through its Task Force Council to establish sectoral energy-intensity
improvement targets and publishes an annual progress report.
Plastics Energy and Greenhouse Gas Savings Using House Wrap
A case study prepared in 2000 for the American Plastics Council and the Environment and
Plastics Industry Council (EPIC) of the CPIA demonstrated the greenhouse gas reduction
benefits associated with applying a plastic house wrap to the exterior of single-family residential
housing in the U.S. and Canada. The life cycle analysis methodology demonstrated that a
CO2-equivalent reduction of between 360 and 1,800 kilograms could be achieved by
reducing energy use for a typical Canadian house on an annual basis. The study also
reported that if all of the houses built in Canada during the period 1991–1995 had
been built with house wrap, the estimated reduction in energy-related greenhouse gas
emissions for Canada would be 1.8 to 8.2 million metric tonnes of CO2 equivalent
over the same period.
Reference: www.plasticsresource.com
3.3 SUMMARY
Energy use by the plastics processing industry in Canada has increased by 36 percent over
the 1999–2004 period. Plastics production increased by 46 percent over the same period.
The resulting energy intensity (energy per unit production) has improved by 15 percent
over the six-year period. These numbers indicate that energy efficiency improvements have
been made by the plastics processing sector and that greenhouse gas emissions per unit of
production have decreased.
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GREENHOUSE GAS EMISSIONS FROM THE PLASTICS PROCESSING INDUSTRY
Discussions with Canadian plastics processors have indicated that there are many opportunities
for increasing energy efficiency and decreasing greenhouse gas emissions, which will be
implemented when the economic factors (payback, rate of return) are favourable. Programs
or specific tools that would assist plastics processors in assessing energy efficiency opportunities
would be of value to the sector and would help the greenhouse gas reduction efforts.
29
Further study is required to determine what tools would be most effective in facilitating
energy efficiency improvements.
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3
4
GENERIC PROCESSES,
PRODUCTS AND
PRODUCT MARKETS
4
GENERIC PROCESSES, PRODUCTS AND PRODUCT MARKETS
4. GENERIC PROCESSES, PRODUCTS AND PRODUCT MARKETS
32
Plastics manufacturing processes covered by this guide include the significant, high-volume
methods for processing thermoplastic materials. Two of the major thermoset processes
are also discussed. Industry estimates suggest that the processes listed below capture
approximately 90 percent of the sector activity. Descriptions and illustrations of these
generic processes can be found in Chapter 5.
Manufacturing operations will benefit from a review of the material presented in this guide.
In addition to resource conservation opportunities for each of the primary processes listed,
all plants in the sector use energy for plant space heating and cooling, material handling,
secondary operations and transportation.
4.1 GENERIC PROCESSES AND TYPICAL PRODUCTS
Plastics manufacturing processes are versatile and capable of producing a wide variety of end
products from a range of thermoplastic and thermoset plastic materials. The production
processes listed below, along with example products, are a small sample of the applications
commonly found.
Six generic thermoplastic processes constituting the majority of production include
the following:
•
Profile extrusion (e.g. pipe, siding, automotive trim)
•
Injection moulding (e.g. containers for retail dairy products, CD cases, pipe fittings)
•
Sheet extrusion (e.g. swimming pool liners)
•
Injection blow moulding (e.g. soft drink bottles, jars)
•
Blown-film extrusion (e.g. garbage bags, shopping bags)
•
Extrusion blow moulding (e.g. detergent and lubricant bottles)
Two significant non-thermoplastic processes are also discussed:
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Compression moulding of thermoset plastics (e.g. automotive panel components,
truck air deflectors)
•
Urethane foam moulding (e.g. automotive seat cushions, impact-absorbing
dashboard components)
ENERGY EFFICIENCY OPPORTUNITIES
IN THE
CANADIAN PLASTICS PROCESSING INDUSTRY
GENERIC PROCESSES, PRODUCTS AND PRODUCT MARKETS
There are many other plastics manufacturing processes that are not discussed in this guide.
These include such processes as reaction-injection moulding, rotational moulding, casting,
thermoforming, vacuum forming, pultrusion, hand lay-up and others. In addition, manufacturers
perform many types of finishing and secondary operations that are also beyond the scope
of this guide. A more comprehensive listing of the generic processes used in Canada are
itemized in Appendix III.
33
4.2 USE OF PLASTIC PRODUCTS IN VARIOUS MARKET
SEGMENTS
A breakdown of the use of plastics in Canada by various end markets and product types are
presented in Figure 4-1. This illustration outlines the broad range of product applications
and also the significance of plastics processing to the Canadian economy.
Figure 4-1 Plastic Products in Various Market Segments
Other
12%
Construction
26%
Electrical and
Electronic
5%
Furniture
5%
Transport
18%
Packaging
34%
Source: CPIA
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4
5
GENERIC PROCESSES
AND AUXILIARY
SYSTEMS
DESCRIPTIONS
5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
5. GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
36
The purpose of highlighting commonly used generic processes is to pinpoint where
opportunities may exist to minimize resource consumption and to reduce process
discharges. Illustrations of generic processes together with process descriptions are
provided in this guide. The process diagrams identify resource inputs and sources of
effluents. Both the descriptions and diagrams are highly simplified and are intended
to introduce the technology to readers who are unfamiliar with the industry.
Several of the processes described below may also be enhanced by feeding more than one
material type, colour or grade into the process to manufacture products with layers of
dissimilar materials. This enables the manufacturer to obtain improved technical-, aestheticor cost-benefits from a single process. In addition, robotics play an increasingly important
role in enhancing repeatability in processes, as well as in reducing cost and the risk of
accidents. To keep things simple, enhancements such as these are ignored throughout the
process descriptions outlined in the text.
Illustrations of auxiliary systems are also provided. Examples of some of the systems
illustrated include a closed-loop free-cooling water system, a compressed-air system and
a pneumatic raw-material handling system. Resource consumption areas and emission
points are pinpointed in each of the generic auxiliary systems described.
Readers already familiar with generic processes, process technology and auxiliary systems
may proceed directly to Chapter 6, “Generic Improvement Opportunities.”
5.1 PROFILE EXTRUSION
Single screw extrusion is the most commonly used technology for profile extrusion. A
thermoplastic raw material, typically in pellet form, is fed from a hopper into a barrel that
houses a rotating screw. A small laboratory-sized extruder may have a screw diameter of
10 mm, while screws for high-volume extruders may have diameters in excess of 300 mm.
The screw is typically driven by a variable speed electric motor that may be coupled to a
single- or multi-speed gear box.
The screw system performs several functions:
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•
It conveys material from the hopper to a die located at the opposite end of the barrel.
•
The screw plasticizes and pressurizes the material. Heat is generated by a combination
of internal heating due to shear and heater bands located outside the barrel. The barrel
may be vented to allow gases and water vapour to escape. Venting requires a multiplestage screw, with a decompression zone between the compression stages.
•
The screw may be used to blend in colorants and other additives.
ENERGY EFFICIENCY OPPORTUNITIES
IN THE
CANADIAN PLASTICS PROCESSING INDUSTRY
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
•
The control of melt temperature, homogeneity and pressure are all critical factors.
Thermocouples are used to sense temperature along the barrel and to control the
amperage to the heater bands. To prevent excessive shear heat from degrading the
material, some barrel zones may be water- or air-cooled.
37
The plasticized material is forced through a die to form the desired shape. After passing
through the die, the partially solidified extrudate may be further formed by callipers or
vacuum sizers to achieve the final desired configuration and to maintain required tolerances.
The extrudate is then water- or air-cooled. When the material has solidified sufficiently to
resist damage from handling, a puller system is used to maintain a constant tension on the
extrudate. Beyond the puller, a travelling saw or shearing mechanism is used to cut the
product into desired lengths for shipment or further processing.
Twin extruders, with two parallel screws, are capable of high output with low shear and are
typically used for large volume processing of heat-sensitive materials. Typical applications
include siding and pipe produced from non-pelletized (powder) materials. Co-extrusion –
the use of more than one extruder to feed a single die – is common.
Most custom operations use various sizes of general purpose extruders. However, significant
productivity, quality and energy efficiencies may be achieved by using a machine matched
to a specific job. For a specific material and throughput, it is important to select the
appropriate screw diameter, length to diameter ratio and operating conditions.
A wide variety of thermoplastic materials may be processed by extrusion. The largest
volume material is PVC (polyvinyl chloride), which is used for construction vinyl siding,
sewer pipe and along windows (or lineals). ABS (acrylonitrile butadiene styrene) is used
for refrigerator trim, drain pipes and furniture components.
Resource Consumption and Emissions in the Profile-Extrusion Process
The major energy requirement for this process is the electricity to drive the extruder-screw
motor. Some electrical energy is used to drive puller motors and cut-off saws. In other cases,
the cut-off equipment may be operated by compressed air.
Significant amounts of water may be used to cool the lineals. This water is often recirculated.
Water vapour and other gaseous emissions are released into the atmosphere from barrel
vents, the feeder throat and the nozzle.
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5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-1 Resource Consumption and Emission Points in the Profile Extrusion Process
38
A
1
LOCAL EXHAUST HOOD TO
ATMOSPHERE
RAW MATERIAL
FEED
REGROUND
MATERIAL FROM
PROCESS
VENT FOR GAS AND WATER VAPOUR
PULLER
DIE
FEED
MOTOR
GEAR
BOX
EXTRUDER
CUT -OFF
EQUIPMENT
EXTRUDATE
COOLING BATH
HEATING
COOLING
1
3
1
Resources Used and Discharges:
1 - Electricity
EXTRUDED PRODUCT
COOLING
3
3 - Cooling
1
1
5 - Compressed Air
or
5
A - Exhaust Air
5.2 THERMOPLASTIC INJECTION MOULDING
Thermoplastic injection moulding is a versatile process used to produce a wide variety of
end products. With proper tool design and material selection, injection moulded parts can
provide a broad range of physical properties, decorative features and resistance to chemical
attack and ageing. When required, metal inserts may be used in injection moulded parts to
provide additional strength.
Injection moulding machines are commonly classified by clamp tonnage – the force
required to resist the pressure exerted by the material injected into the mould during the
injection process. The pressures are frequently high, 20,000–30,000 psi. As a result,
clamp tonnages normally range from 20 tonnes for a small machine to 6,000 tonnes or
more for a large press.
The plasticizing of the material is similar to the process described under the profile-extrusion
process description. The major difference is that in the injection-moulding process, the screw
retracts while it is rotating and a pre-determined amount of plasticized material accumulates
in front of the screw. The screw stops rotating at this point, and the screw assembly moves
forward to force the material through a nozzle into a mould under high pressure.
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Cycle times vary with materials used, wall thickness of the parts and tool technology.
Thin-walled containers typically have a cycle time of a few seconds. Large parts with heavy
sections will take several minutes to solidify before being removed from the mould.
39
For parts that require trimming, 100 percent inspection or secondary operations, an
operator manually removes the parts from the mould. Alternatively, the parts may be
allowed to fall into a container, or robots (sprue pickers) may be used to remove the
sprues and/or parts from the mould. In more sophisticated applications, robots are used
to package the parts or to transfer them to a secondary operations station.
Various options exist for feeding the material into the mould cavities. The conventional
method is to feed material through a sprue and a runner system into one or more mould
cavities. After the part has solidified, the mould opens and the parts may be trimmed from
the runner system. In most applications, the sprues and runners are reground and fed back
into the process.
Various levels of sophistication in tool technology help reduce the labour and energy
required to trim parts after moulding. For example, tunnel or submarine gates are used
to separate the part from the runner system during the mould-opening sequence.
The effort to separate and re-grind runners may be totally eliminated by using a hot-runner
system. Heaters built into the mould keep material in the runners in a molten state until
the next shot. Although hot-runner tooling is more costly, the technology is commonly
used for high-volume small parts, especially when heat-sensitive materials are used. With
conventional tooling, the runner-to-part weight ratio is typically quite high, and materials
may become degraded by passing through the heating cycle several times.
Injection moulding is used to process a broad range of materials. Commodity resins, such
as polyethylene, are found in ice cream tubs and polystyrene is found in CD cases.
When the end-use requires physical or chemical properties that are not available in commodity
grades, engineered plastics are used. Nylon, for example, is frequently used in applications
that require toughness and lubricity. Some ABS parts, such as faucet handles and
automotive trim, are electroplated for decorative and functional applications.
Resource Consumption and Emissions in the Injection-Moulding Process
The major energy requirement for this process is the electricity to power the hydraulic
systems. The majority of the energy is used to plasticize the material, with lesser amounts
required for injection and to transport the moulds.
The moulds are usually water-cooled. This water is typically recirculated.
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5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Water vapour and other gaseous emissions are released into the atmosphere from barrel
vents, the feeder throat and the nozzle. Mould releases, if used, will also contribute to air
emissions. Mould cooling water is typically recirculated. Leaks from the hydraulic systems
may contaminate plant wastewater.
40
Figure 5-2 Resource Consumption and Emission Points in the Injection-Moulding Process
A
1
LOCAL EXHAUST HOOD TO
ATMOSPHERE
RAW MATERIAL
FEED
REGROUND
MATERIAL FROM
PROCESS
POWER FOR HOT
RUNNER MOULDS
1
PLATTEN
FEED
HYDRAULIC RAM
7
HYDRAULIC
MOTOR
7
INJECTION UNIT
HEATING
TO OPEN/CLOSE MOULD
COOLING
MOULD
7
1
3
COOLING
3
MOULDED PRODUCT
EJECTED
Resources Used and Discharges:
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ENERGY EFFICIENCY OPPORTUNITIES
IN THE
1 - Electricity
3 - Cooling
7 - Hydraulic Pressure
CANADIAN PLASTICS PROCESSING INDUSTRY
A - Exhaust Air
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
5.3 FLAT FILM OR SHEET EXTRUSION
41
In this process, a slot die, often three to four metres wide, is mounted on an extruder to
produce a film. This film is typically fed vertically into a cooling bath and is passed over
chilled rolls. The highly polished rolls produce a smooth flat film surface that has excellent
clarity. Film thickness is partially a function of the cooling rate. Accurate temperature control
of the rolls and cooling baths is important.
The roll mechanism is run at a speed that stretches the film, while reducing its thickness.
This process produces a film that has superior physical properties in the direction of the
stretch and lower properties across the film. Biaxially oriented film with good strength
in all directions may be obtained by stretching the extruded film both longitudinally
and transversely.
Sheet may be produced with a wide range of thicknesses, from thin film for packaging
applications to heavier gauges used by whirlpool tub manufacturers. Sheet may be co-extruded
from more than one type of material and may be supplied with embossed surfaces.
A wide range of polymers may be processed by sheet extrusion; polyethylene, polypropylene
and polystyrene are commonly used.
Resource Consumption and Emissions in the Flat-Film or Sheet-Extrusion Process
The major energy requirement for this process is the electricity to drive the extruder screw
motor. Some electrical energy is used to drive rolls and winder motors. Significant amounts
of water may be used for the chill rolls and cooling baths. This water is often recirculated.
Water vapour and other gaseous emissions are released into the atmosphere from barrel
vents, the feeder throat and the die area.
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5
5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-3 Resource Consumption and Emission Points in the Flat-Film or Sheet-Extrusion Process
42
A
1
LOCAL EXHAUST HOOD TO
ATMOSPHERE
RAW MATERIAL
FEED
VENT FOR GAS AND WATER
VAPOUR
FEED
MOTOR
WINDER
GEAR
BOX
EXTRUDER
DIE
ELECTRICITY
HEATING
COOLING
1
1
3
1
CHILL ROLLERS
1
Resources Used and Discharges:
1 - Electricity
and
3
3 - Cooling
A - Exhaust Air
5.4 BLOWN-FILM EXTRUSION
In this process, plasticized material is forced through a ring-shaped die. Die diameters may
range from a few centimetres to over two metres. The technology required to distribute
the melt evenly around the die and to attempt to produce uniform-film gauge thicknesses
is complex.
The tube formed by the die is expanded into several times its original diameter by air pressure
introduced through the die. Air blown from a ring outside the bubble, which may be several
storeys high, is used to cool the material from the outside. Both the external and internal
air streams may be chilled. Automatic air rings may be used to allow individually controlled
air streams to be directed at specific areas of the bubble. Automatic measurements of film
thickness are used to feed back information to control the velocity and/or the temperature
of the individual air streams.
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Once the material has solidified, the bubble is passed through a collapsing frame into
pinch rolls. These rolls permit a constant pressure to be maintained inside the bubble by
preventing the loss of air that is introduced through the die. The air pressure is used to
control the size of the bubble and, consequently, the thickness of the blown film.
43
Products such as garbage bags are made from a single polymer. More complex products
that require specific barrier properties, such as medical applications or food wraps, may
be produced from as many as seven different materials co-extruded in a single process.
The blown film may be slit and wound on rolls as flat film. Alternatively, the film may
undergo several additional processes in-line. It may be treated to improve adhesion for
glues and inks, printed, gusseted, and cut into products such as grocery bags.
Throughputs in excess of 1,500 kilograms per hour have been achieved.
Polyethylene is the most commonly used polymer for high-volume blown-film
extrusion applications.
Resource Consumption and Emissions in the Blown-Film Extrusion Process
The major energy requirement for this process is the electricity to drive the extruder
screw motor. Significant energy is used to drive cooling fan motors and lesser amounts
are required for winder equipment.
Water vapour and other gaseous emissions are released into the atmosphere from barrel
vents, the feeder throat and the die area.
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ENERGY EFFICIENCY OPPORTUNITIES
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5
5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-4 Resource Consumption and Emission Points in the Blown-Film Extrusion Process
44
A
1
LOCAL EXHAUST HOOD TO
ATMOSPHERE
RAW MATERIAL
FEED
BUBBLE
WINDER
VENT FOR GAS AND WATER
VAPOUR
HIGH VOLUME LOW
1
PRESSURE FAN
DIE
1
FEED
3
MOTOR
GEAR
BOX
EXTRUDER
COOLING RING
ELECTRICITY
HEATING
COOLING
1
1
3
5
COMPRESSED AIR FOR
INFLATING
Resources Used and Discharges:
1 - Electricity
3 - Cooling
5 - Compressed Air
A - Exhaust Air
5.5 BLOW MOULDING
5.5.1 EXTRUSION BLOW MOULDING
In this process, a screw plasticizes material that is forced through a ring-shaped die to form
a tube of material called a parison. For small parts, the extrusion of the parison may be
continuous, in which case the maximum size of the part is limited by the tendency of the
parison to stretch under its own weight. For larger parts, or more-difficult-to-process
engineering materials, the melt is collected in an accumulator system and is injected
intermittently by a plunger. Reciprocating screws, operating in the same manner as for
injection moulding, may also be used to form a parison. To conform with product and
process demands to have more or less material in specific areas of the part, moving mould
components can be used to vary the thickness of the parison while it is being formed.
The parison of molten material is captured between mould halves. Air is injected into the
parison to inflate the material into contact with the mould walls. After cooling, the part is
ejected and trimmed of flash. Typically, multiple moulds are shuttled or rotated to allow
cooling to take place while another mould is capturing the subsequent parison. Since the
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pressure exerted by the air, which is used to expand the parison, is relatively low, moulds
can be made of aluminum. However, polished steel moulds are typically used for parts that
require a good surface finish. Moulds may be either cooled or heated, depending on the
materials used and the appearance requirements of the finished product.
45
5.5.2 INJECTION BLOW MOULDING
Large quantities of containers, such as bottles or jars, with a good surface finish and tight
tolerances may be produced by injection blow moulding. This process typically uses a
three-station indexing table. The first station is used to injection mould a preform. At the
second station, the preform is introduced into another mould and is blown to form the
finished product. The third station is used for parts removal.
Alternatively, a preform may be produced in a separate injection-moulding machine. For
high volume applications, such as beverage containers, the injection mould may have over
one hundred cavities. The preform is later re-heated and inserted into a blow-moulding
machine. This process permits more complex shapes and a more economical use of
raw materials.
Polyethylene, polystyrene and polyethylene terephthalate resins are commonly used materials
for packaging applications and beverage containers.
Resource Consumption and Emissions in the Blow-Moulding Process
The major energy requirement for this process is the electricity to drive the extruder screw
motor. Some electrical energy is used to drive mould-transport mechanisms, whether
electrically or hydraulically operated, and to provide compressed air for blowing. In
injection blow moulding, gas may be used to re-heat preforms. Cooling water, often
recirculated, may be used for moulds.
Water vapour and other gaseous emissions are released into the atmosphere from barrel
vents, the feeder throat and the nozzle. When gas is used for heating preforms, the
combustion contributes to air emissions.
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5
5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-5 Resource Consumption and Emission Points in the Blow-Moulding Process
46
A
1
LOCAL EXHAUST HOOD TO
ATMOSPHERE
RAW MATERIAL FEED
FROM DRYER OR
BLENDER
RECYCLED
MATERIAL
PROCESS SCRAP
GRINDER
VENT FOR GAS AND
WATER VAPOUR
1
FEED
MOTOR
1
GEAR
BOX
SEPARATE HYDRAULIC
SYSTEM
TO CONTROL TIP
EXTRUDER
COMPRESSED
AIR
HEATING
COOLING
1
2
OR
2
5
OR
3
TRANSPORT
PARISON
POWERED BY
ELECTRICITY OR
HYDRAULICS
SHUTTLE OR
ROTARY
MOULDS
TRANSPORT
7
HYDRAULICS FOR
MOULD CLAMPING
COMPRESSED
AIR
COOLING WATER
3
Resources Used and Discharges:
1 - Electricity
2 - Thermal Oil
3 - Cooling
5 - Compressed Air
5
MOULD REMOVAL AND
DE-FLASHING
7 - Hydraulic Power
A - Exhaust Air
5.6 COMPRESSION MOULDING OF THERMOSET PLASTICS
Thermoset plastics behave differently when heated. These materials undergo an irreversible
chemical process when heated and cannot be re-plasticized. The five processes described
earlier (sections 5.1–5.5) commonly use thermoplastic materials. These soften when heated
and re-harden when cooled. For most thermoplastics, this melting and cooling process can
be repeated a number of times without a significant loss of physical properties.
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Thermoset raw materials are supplied in either granular form or as sheet moulding
compounds, which are supplied in rolls of a putty-like sheet. Typically, sheet moulding
compounds contain a proportion of glass fibres that impart improved physical properties
to the end product.
47
In compression moulding, a pre-weighed amount of thermoset material is placed into a
mould cavity. Some thermoset materials can be moulded at ambient temperatures. However,
shorter cycle times are achieved by using heated moulds. The heated mould is closed under
hydraulic pressure (often as high as 5,000 psi) and the material flows to fill the mould.
The clamping capacity of a large compression-moulding machine may exceed 10,000 tons.
The low cost, low weight and high strength of glass-filled compression-moulded products
has led to an increased penetration of this technology into many mass transportation and
automotive applications.
Thermosetting polyesters, typically with added glass fibre, are commonly used in
compression-moulding applications.
Resource Consumption and Emissions in the Compression-Moulding Process
The major energy requirement for this process is the electricity to drive the hydraulic
system for the press. Energy is also required to heat the moulds, either directly through
resistance heating, by thermal oil or by steam. Emissions from the moulding compound
are released into the air during the process. Oil leaks from the hydraulic systems may
contaminate stormwater.
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5
5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-6 Resource Consumption and Emission Points in the Compression-Moulding Process
48
OPEN/CLOSE MOULD
EJECT PARTS
7
Mould
CONTROLLED
MATERIAL AMOUNT
MATERIAL LOADING
FURTHER
PROCESSING
HEATING
1
1
Resources Used and Discharges:
1 - Electricity
OR
2
2 - Thermal Oil
OR
5
6
5 - Compressed Air
6 - Steam
7 - Hydraulic Power
5.7 FOAM MOULDING
The foam-moulding process introduces a mixture of liquid raw materials into a mould.
This mixture undergoes a chemical reaction and expands to fill the mould. For fast-reacting
foams, closed moulds are used in a process called reaction injection moulding. Slower acting
foams may be poured into open moulds, which are then closed while the foam expands to
fill the mould.
To ensure consistency in the finished product, a precise control of the raw material mixing
is necessary. Low-pressure mixing technology, used for filling open moulds, is capable of
accurately metering and mixing 10 different ingredients with shot sizes ranging from a few
grams to hundreds of kilograms.
For high-volume production, a single mixing head is used to fill a series of moulds that
travel on a conveyor system while the foam cures. The moulds are opened at an unloading
station and the finished parts are removed. For certain applications, inserts may be loaded
into the mould.
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A trimming operation is often required to remove unwanted flash from the parts.
The blowing agents and other chemical components may also be controlled to produce
foams of various densities. Rigid foams are frequently used for insulation, while flexible
foams are commonly found in furniture, car seats and energy-absorbing padding.
49
Polyurethanes are the most frequently used family of materials.
Resource Consumption and Emissions in the Foam-Moulding Process
The major energy requirement for this process is the electricity to drive the material-dispensing
systems. Lesser amounts are required for mould transport and for hydraulic-mould operating
systems, when used.
Most foam-moulding processes do not use cooling water. However, the use of solvents
to clean dispensing equipment may generate liquid wastes that need special handling.
Air emissions include releases from the curing material, solvents and mould releases. Solid
waste from the trimmings and other scrap are often recycled in carpet underpadding.
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5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-7 Resource Consumption and Emission Points in the Foam-Moulding Process
50
1
5
RECIRCULATION BACK TO
TANK FOR SHOT PROCESS
1
OR
7
PRESSURIZATION*
MATERIAL SUPPLY
AGITATOR*
FOR LOW PRESSURE
SYSTEMS ONLY
3
METERING PUMP
CONTROLLED BY VARIABLE
FREQUENCY DRIVE
COOLING**
TO BLOW OUT HEAD OF
SHOT MACHINES***
5
HEAT EXCHANGER
8
HEATING*
MIXING
HEAD
7
1
HYDRAULICS FOR MOULD
OPENING/CLOSING ON HIGH
PRESSURE SYSTEMS
1
B
SOLVENT TO FLUSH
CHAMBER OF SHOT
MACHINES***
SPENT SOLVENT: HOT WATER
RECYCLED OR METHYLENE
CHLORIDE DISPOSED
* DEPENDS ON MATERIAL
** ONLY WITH HIGH PRESSURE PROCESS
*** ONLY WITH LOW PRESSURE SHOT PROCESS
7
MOULD
HYDRAULIC PRESSURE TO
KEEP MOULD CLOSED FOR
HIGH PRESSURE PROCESS
MOULD OPTIONS:
· HYDRAULIC OR ELECTRIC MOULD TRANSFER
· STATIONARY MOULDS WITH MOVING HEAD
· CONTINUOUS MOULDING
Resources Used and Discharges:
1 - Electricity
3 - Cooling
5 - Compressed Air
7 - Hydraulic Power
8 - Solvent
B - Spent Solvent
5.8 AUXILIARY SYSTEMS
In addition to the primary processes described above, most plants also use several auxiliary
systems such as those listed below.
Cooling Systems – Once Through and Closed Loop
Once-through cooling uses line water to remove heat from the equipment or process prior
to discharging to the sewer system. Closed-loop cooling reuses the water by removing the
heat that is absorbed from the process by circulating the water either through a chiller or a
cooling tower.
Closed-Loop “Free” Cooling System
A free cooling system uses ambient outside air to reduce chiller-system energy
requirements in cool weather.
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Hydraulic Power Unit System
Hydraulic power units are composed of a hydraulic pump usually driven by an
electric motor. The pump pressurizes hydraulic fluid, which in turn powers a variety
of components such as hydraulic cylinders and hydraulic motors.
51
Thermal Oil Heater/Cooler Systems
Thermal oil heater/cooler systems consist of a tank filled with thermal oil, a pump and
either a heater or cooling element. The thermal oil is used to control the temperature of
the equipment or process.
Compressed-Air System
Compressed air is used for a variety of applications within a plant that includes powering
cylinders, motors and actuators. The compressed-air system consists of a motor driving a
compressor that compresses air into a receiver. From there, the air typically goes through
a dryer before being distributed throughout the plant to various applications.
Pneumatic Raw Material Handling System
A pneumatic raw material handling system is used for the transfer of larger quantities of
materials such as pellets within a plant. In addition to the pneumatic conveying system,
depending on the type of material, a mixing or blending system and a dryer may be
included in the system.
The above-mentioned processes are illustrated in Figures 5-8, 5-9, 5-10 and 5-11.
Resource use and discharges are pinpointed in each of the auxiliary system illustrations.
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Figure 5-8 Auxiliary Processes – Once-Through and Closed-Loop Cooling Water Systems
52
ONCE -THROUGH COOLING WATER SYSTEM
3
CITY OR WELL WATER
COOLING WATER TO PROCESS
AND AUXILIARY EQUIPMENT
RETURN FROM PROCESS AND
AUXILIARY EQUIPMENT
E
DISCHARGE TO SEWER
CLOSED -LOOP COOLING WATER SYSTEM
EVAPORATION LOSS
RETURN WATER FROM PROCESSES
SUCH AS:
· BARREL COOLING
· HYDRAULIC COOLING
· AIR COMPRESSOR
D
COOLING
TOWER
1
COOLING
TOWER TANK
PUMP
3
CONDENSER
1
EVAPORATOR
COOL WATER TO:
· BARREL COOLING
· HYDRAULIC COOLING
· AIR COMPRESSOR
COMPRESSOR
RETURN FROM PROCESSES SUCH
AS:
· MOULDS
· BARRELS
· CHILL ROLLERS
· HEAT EXCHANGERS
1
1
CHILL TANK
PUMP
3
Resources Used and Discharges:
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IN THE
1 - Electricity
3 - Cooling Water
D - Evaporation
CANADIAN PLASTICS PROCESSING INDUSTRY
CHILLED WATER TO:
· MOULDS
· BARREL COOLING
· CHILL ROLLERS
· EXTRUDATE HEAT
EXCHANGER
E - Used Cooling Water
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-9 Auxiliary Processes – Closed-Loop “Free” Cooling Water System
53
EVAPORATION LOSS
RETURN WATER FROM PROCESSES
SUCH AS:
· BARREL COOLING
· HYDRAULIC COOLING
· AIR COMPRESSOR
D
COOLING
TOWER
1
COOL WATER TO:
· BARREL COOLING
COOLING
TOWER TANK
PUMP
· HYDRAULIC COOLING
3
RETURN FROM PROCESSES
· AI R COMPRESSOR
SUCH AS:
CONDENSER
· MOULDS
· BARRELS
· CHILL ROLLERS
1
EVAPORATOR
COMPRESSOR
· HEAT EXCHANGERS
1
1
CHILL TANK
3
To use “free” cooling, the ambient temperature needs to be
less than 13 degrees Celcius. The chiller portion
of the cooling circuit is denoted by
passed with lines denoted by
to provide the
required cooling through the cooling tower.
Resources Used and Discharges:
1 - Electricity
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3 - Cooling Water
D - Evaporation
ENERGY EFFICIENCY OPPORTUNITIES
E - Used Cooling Water
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5
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-10 Auxiliary Processes – Hydraulic Power and Thermal Oil Systems
54
HEAT
EXCHANGER
HYDRAULIC POWER SYSTEM
RETURN HYDRAULIC FLUID
FROM SERVICE
HIGH PRESSURE
HYDRAULIC PUMP
HYDRAULIC OIL
TANK
3
COOLING WATER
7
PRESSURIZED HYDRAULIC FLUID
TO MOULD CLAMPING, CONVEYING
SYSTEMS, MOTORS AND RAMS
HEATER
1
F
1
HYDRAULIC OIL LEAKS
FROM ENTIRE SYSTEM
THERMAL OIL SYSTEM
HEAT
EXCHANGER
RETURN THERMAL OIL
THERMAL OIL
TANK
HEATER – ONLY WHEN OIL
IS USED FOR HEATING
1
THERMAL OIL
CIRCULATION PUMP
F
3
COOLING WATER – ONLY WHEN USING
OIL FOR COOLING
2
THERMAL OIL-TO-HEAT EXTRUDER BARREL OR
COMPRESSION MOULDS; MAY ALSO BE USED TO COOL
EXTRUDER BARREL
1
THERMAL OIL LEAKS
Resources Used and Discharges:
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1 - Electricity
IN THE
2 - Thermal Oil
3 - Cooling Water
CANADIAN PLASTICS PROCESSING INDUSTRY
7 - Hydraulic Power
F - Oil Leaks
GENERIC PROCESSES AND AUXILIARY SYSTEMS DESCRIPTIONS
Figure 5-11 Auxiliary Processes – Compressed-Air and Pneumatic Material Handling Systems
55
COMPRESSED-AIR SYSTEM
AIR INTAKE
AIR
COMPRESSOR
1
AIR
RECEIVER
5
AIR DRYER
COMPRESSED AIR TO PLANT
AND PROCESS
3
1
C
CONDENSATE
DUST TO ATMOSPHERE
D
PNEUMATIC RAW MATERIAL
HANDLING SYSTEM
5
DUST COLLECTOR OR
CYCLONE
1
INCOMING MATERIAL
CONTAINERS
PNEUMATIC
CONVEYING
SYSTEM*
1
MIXING/BLENDING
SYSTEM**
DRYER**
TO FEED HOPPER
OR BLENDING
SYSTEM
1
* OPTIONAL DEPENDING ON
THE SIZE OF THE OPERATION
1
OR
4
** NOT REQUIRED FOR ALL MATERIALS
Resources Used and Discharges: 1 - Electricity 3 - Cooling Water
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4 - Natural Gas 5 - Compressed Air 7 - Hydraulic Power C - Condensate D - Dust
ENERGY EFFICIENCY OPPORTUNITIES
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5
6
GENERIC
IMPROVEMENT
OPPORTUNITIES
6
GENERIC IMPROVEMENT OPPORTUNITIES
6. GENERIC IMPROVEMENT OPPORTUNITIES
58
Each plastics processing facility is uniquely designed and may use a variety of technologies
to serve the needs of a specific market. As a result, there will be significant differences
in processing conditions, energy and water use, and emissions levels. The opportunities
in this chapter will need to be evaluated on an individual basis taking into account
current operations.
Typical manufacturing expense breakdowns for injection moulders and film processors are
illustrated in Figure 6-1 and Figure 6-2, respectively. Most of the other processes discussed
in this guide will have similar cost structures. This chapter deals with major cost-saving and
resource-conservation opportunities in an order of probable cost impact. As illustrated in
Figure 6-1 and Figure 6-2, direct material costs typically constitute 50 to 70 percent of the
total manufacturing expenses. Material savings opportunities are discussed first, followed
by energy, water and other resource conservation topics.
Process-specific case studies of energy saving opportunities for injection-moulding,
extrusion and blow-moulding plants are presented in Appendix IV. These studies
also illustrate process, auxiliary equipment and plant energy-savings opportunities for
operations with various electrical power demands.
6.1 MATERIAL CONSERVATION
Opportunities to reduce resin consumption by improved material handling and processing
are discussed in this section, in addition to enhancements in operating procedures and
innovative business practices. Opportunities associated with plant maintenance, consumable
supplies and packaging are also discussed. Resin conservation topics include the following:
•
better material handling and storage;
•
enhanced processing conditions and handling of regrind; and
•
improved sales, purchasing and scheduling policies.
6.1.1 GENERAL PLANT SUPPLIES
Plastics processors use a variety of cleaning and building maintenance supplies, common
to all manufacturers. A significant reduction in the use of these supplies may be achieved
by improved material handling, housekeeping and maintenance practices.
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6.1.2 CONSUMABLES AND MAINTENANCE SUPPLIES
59
Typical consumable supplies in the industry include hydraulic oils, mould-release agents
and solvents. Reduction and potential substitution of these materials is discussed in
Section 6.5, “Emissions Reduction.”
Figure 6-1 Total Manufacturing Expense Breakdown – Typical Injection Moulder
Other
Manufacturing
Expenses
14%
Depreciation
5%
Direct Materials
51%
Manufacturing
Wages, Salaries
and Benefits
30%
Note: Other manufacturing expenses include energy, manufacturing and maintenance taxes (except income tax),
freight, etc. (Source: CPIA)
Figure 6-2 Total Manufacturing Expense Breakdown – Typical Film Manufacturer
Other
Manufacturing
Expenses
13%
Depreciation
3%
Manufacturing
Wages, Salaries
and Benefits
13%
Direct Materials
71%
Note: Other manufacturing expenses include energy, manufacturing and maintenance taxes (except income tax),
freight, etc. (Source: CPIA)
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6.1.3 RESIN CONSERVATION
60
In most plastics processing operations, material costs constitute by far the largest single
portion of manufacturing expense. A reduction in resin use has an obvious direct cost
benefit and also supports the processor’s emission reduction objectives.
Large-volume resin users, such as major siding and pipe producers, often compound resins
in-house by adding lubricants, stabilizers and other processing aids and additives. This
processing technology is not one of the major generic processes discussed in this guide.
This guide assumes that the thermoplastic processors are receiving pre-compounded resins
in pellet form.
Resin conservation is discussed under the following three major headings:
1) Pellet Control Program, 2) Reducing Material Use in Processing and 3) Regrind.
6.1.3.1 Pellet Control Program
Significant costs may be incurred through improper handling of raw materials. Savings may
often be realized with little or no investment. A company policy that insists on an immediate
cleanup of all material spills, preferably by the individual responsible for the spill, encourages
improved practices and reduces the frequency of spills caused by careless handling of materials.
In support of this policy, a program to keep employees informed about the price of pellets
increases awareness of this important issue. A reduction of pellet spills will also improve
safety, as pellet spills can constitute a significant safety hazard.
The following suggestions are offered to help prevent pellet loss and reduce costs:
a) Unloading from tank trucks or rail cars (Material losses may occur during the
sampling of incoming material, purging of lines and the transfer of pellets from a
tanker truck or rail car to a plant silo):
•
tarps or containers should be provided to catch pellets and the unloading area should
be paved to facilitate cleanup; and
•
trucks and rail cars should be inspected to ensure that they are completely empty
after unloading.
b) Warehousing and handling of material bags and gaylords:
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•
containers should be inspected for damage and replaced or repaired
during unloading;
•
proper handling procedures, especially by forklift drivers, should be followed
to minimize handling damage;
•
all partially filled containers should be clearly identified to minimize accidental
mixing of materials;
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•
all containers should be covered to prevent contamination; and
•
all containers should be fully emptied prior to disposal/recycling.
61
c) Material spillage and contamination during blending, drying and handling
within the plant:
•
over-filling of pails and other containers should be discouraged; and
•
dryers and hoppers should be emptied and cleaned prior to material or
colour changes.
Guidelines for a comprehensive pellet-handling program are available from The Society
of the Plastics Industry, Inc. by calling 202-974-5200 or visiting www.socplas.org.
6.1.3.2 Reducing Material Use in Processing
The overall consumption of raw materials is influenced by many factors in manufacturing.
Savings may be realized from both management policy changes and technical improvements.
Sales policies
Many small custom processors serve markets that demand a vast variety of material specifications
and colour options. It is typically very difficult to match material purchases precisely to the
production quantities. At the end of a contract, the processor may have small quantities of
materials left, with no current use. These assorted materials often accumulate for many years
and are eventually sold at a loss or sent to landfill. If possible, flexible shipping quantities
should be negotiated with suppliers to ensure that non-standard materials are fully used.
Scheduling
In most processes, start-ups and material or colour changes create material waste due to
purging losses, mixing of resin types or colours during the changeover and a quantity of
off-specification product that is produced before the process becomes stable. The following
scheduling practices will help to minimize these losses:
•
longer runs;
•
continuous operation;
•
“quick die-change” practices; and
•
scheduling similar materials and colours together.
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Process conditions
62
Material can be degraded due to overheating in the process. All materials should be
processed in accordance with manufacturers’ recommendations. Poor instrumentation,
contaminated raw material and worn-out or damaged screws and barrels also contribute
to material degradation.
6.1.3.3 Regrind
Whenever possible, materials that can be reground should be processed during
the production run and fed directly back into the process. This eliminates multiple
handling, risk of contamination and the opportunity for hygroscopic materials to
absorb moisture.
6.2 ENERGY CONSERVATION
In the majority of processes discussed, a significant percentage of the total energy demand
is consumed by the extruder drive system. Variable speed drives discussed in this chapter
have shown energy savings of up to 20 percent in some extruder drive applications. Mould
clamping system energy savings of up to 45 percent are achievable by using a combination
of technologies.
The Canadian Industry Program for Energy Conservation (CIPEC) published detailed
studies of Energy Efficiency Opportunities in the Plastics Industry for the following three
key processes: 1) Extrusion, 2) Injection Moulding and 3) Blow Moulding. These studies
also cover auxiliary and plant systems. A significant portion of the savings may be achieved
without significant capital spending.
Excerpts from the CIPEC studies are provided in Table 6-1.
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Table 6-1 Major Energy Savings Opportunities – Process Equipment
63
Process
Extruder drive system
Energy Saving Technique
Potential
Saving %
Specify correct size and speed of motor for
application. Investigate high-efficiency motors.
20
Extruder barrel heating
Insulate extruder barrel.
15
Use variable hydraulic power to match load
requirements. May be achieved by using variable
speed drives, variable displacement pumps,
accumulators and control systems.
45
Centralized hydraulic
system
Arrange for one central hydraulic power system to
supply a group of machines.
50
Compressed-air
system operation
Ensure system is correctly sized, well-maintained
and that the compressors are “staged.”
20
Mould-closing, transport
and clamping systems
6.2.1 SPECIFYING ENERGY-EFFICIENT EQUIPMENT
Historically, many new equipment purchases have been evaluated on the basis of capital
cost, installation cost, throughput and projected maintenance expense. Energy costs and
resource utilization issues have received less attention.
Today, most machinery and process equipment vendors are well prepared to discuss
projected energy costs. While the data presented by vendors typically describes ideal
operating conditions, comparisons of energy efficiency are possible in most cases and
should be factored into the purchasing decision.
Other important criteria that may be easily overlooked include:
•
noise levels;
•
access for maintenance and spill cleanup;
•
ease of housekeeping; and
•
safety.
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6.2.2 REPLACING INEFFICIENT EQUIPMENT
DURING MAINTENANCE
64
Many opportunities for improvement can be missed when maintenance is carried out
under emergency conditions. The normal tendency is to replace existing equipment with
an identical spare. For example, a burned-out electric motor represents an opportunity to
evaluate the benefits of replacing it with a high-efficiency unit. The economics may not
favour replacing a working motor with a high-efficiency one, but the calculations may
show a good payback if the original has failed and requires a replacement.
Significant savings may also be achieved at little or no cost by following a regular,
well-documented maintenance program. Proper maintenance procedures and schedules
are generally available from equipment manufacturers. A well-documented program
would schedule and co-ordinate inspection and preventive maintenance of equipment
and housekeeping procedures instead of running equipment until it fails.
6.2.3 MOTORS
When purchasing new equipment or replacing worn-out motors, consider specifying
high-efficiency motors especially in high-load or high-running hours applications.
Motors should be sized to operate between a 75 and 100 percent load. For non-critical
applications with constant load such as fans, size as close as possible to 100 percent.
Do not oversize in anticipation of more capacity unless this requirement is reasonably
predictable. Oversizing results in higher capital cost for the larger motor, cabling and
starters, and incurring higher operating costs due to a power factor penalty.
Some of the advantages of a high-efficiency motor include:
GUIDE
TO
•
operating savings;
•
extended winding and bearing life;
•
improved power factor;
•
reduction or elimination of power factor penalties;
•
reduction or elimination of capacitors used for power factor correction;
•
increased ability to cope with short-term overloads; and
•
less heat generation resulting in longer life and lower cooling requirements
for the motor.
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65
Payback Calculation
kW Saved = hp x 0.746 x (1/Standard Efficiency - 1/High Efficiency)
hp = Mechanical Power Requirement
$ Saving = kW Saved x Annual Operating Hours x Average Energy Cost
Payback = Price Premium for High-Efficiency Motor
$ Saving
High-efficiency motors typically use from 1 to 4 percent less electricity than standard motors,
and for a given application, high-efficiency motors will last longer and be more reliable.
The CIPEC Energy-Efficient Motor Systems Assessment Guide (2004) provides excellent
information on selecting motor systems and provides the following “Rules of Thumb”
when considering purchase of high-efficiency motors (HEMs):
1)
Specify HEMs for new installations operating more than 3,500 hours per year.
2)
Select HEMs for motors that are loaded greater than 75 percent of full load.
3)
Buy new HEMs instead of rewinding old, standard efficiency motors.
4)
Specify HEMs when purchasing equipment packages.
5)
Use HEMs as part of a preventative maintenance package.
6.2.4 VARIABLE SPEED DRIVES
For applications with varying loads such as fans, blowers and pumps, variable speed
drives (VSDs) should be considered for installation. The advantages of using VSDs
include the following:
•
energy savings of 10 to 40 percent over constant-speed motors, depending
on the application;
•
reduced wear on the motor by running it at reduced speed and torque for
reduced capacity conditions; and
•
gentle starting, which reduces power surges and wear on mechanical components.
In addition, VSDs can improve the process in applications that require control of the speed
of rotation of components. An example is screw drives to maintain proper feed rates.
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VSDs can also replace traditional damper controls for controlling gas-flow rate, allowing
centrifugal fans and blowers to operate over a wider range without the danger of surging.
Pumps too can be operated over a wide range by controlling the pump speed instead of
throttling the flow with control valves. Other advantages of VSDs are reduced cooling
costs, plant noise, and wear on the motors and the equipment they are driving.
66
There are various types of VSDs: silicon-controlled rectifiers (SCRs) with DC motors,
variable-speed (VS) AC drives and Brushless DC (BDC) drives. SCR systems are not as
efficient as the other two types; in addition, the SCR-DC system is maintenance-intensive.
The most efficient is the BDC, but its cost is higher than that of the AC drive.
The advantages of BDCs include a greater speed range, much more precise speed
regulation, full torque capacity, higher-efficiency rating, smaller size for the same
horsepower and lower maintenance. The power factor is also higher than that of
AC induction systems.
The most significant disadvantage to VSD motors is their increased cost, which must
be evaluated against the life-cycle energy savings and the value of the other advantages.
Software to calculate energy savings is available for free either directly from vendors or
by downloading it off the Internet from their Web sites. The drive application must be
evaluated to understand the savings potential as not all applications are good energy
savings opportunities.
•
Variable torque loads – effective speed ranges are from 50 to 100 percent maximum
speed and can result in substantial energy savings.
•
Constant power loads – typically, these applications offer no energy savings at
reduced speeds.
•
Constant torque loads – typically, these applications result in moderate energy
savings at lower speeds.
Source: CIPEC Energy-Efficient Motor Systems Assessment Guide (2004)
A more detailed analysis of adjustable or VSD systems is provided in the
above-noted reference.
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6.2.5 HYDRAULIC PUMPS
67
The following is a list of things to take into account regarding hydraulic pumps:
•
Operate them at more than 75 percent capacity; otherwise, a severe energy penalty
is incurred.
•
Do not use pressure compensating pumps because it wastes energy.
•
Use variable volume (displacement) type of pumps or multiple, independently-driven,
fixed displacement pumps. This option requires programmable logic controller control
equipment and good maintenance to run properly.
6.2.6 HYDRAULIC SYSTEMS
When operating hydraulic systems, you should do the following:
•
Use accumulators, especially for injection moulding.
•
Whenever possible, power multiple hydraulic motors and cylinders from a single,
central hydraulic system, especially a group of injection-moulding machines. In this
way, the power requirement of the multiple machines tends to be smoothed out;
maintenance costs are also reduced.
•
By operating multiple machines from a single hydraulic system, a sophisticated control
system is not required. Also older machines can take advantage of considerable energy
savings without having to retrofit their components.
•
In setting up a single hydraulic system, segregate machines or functions into similar
pressure requirements; you may need to add load-sensing device if the pressure
requirement is not continuous.
•
On injection presses, there should be two cylinders – a small-diameter, long-stroke
cylinder for mould transport and a large-diameter, short-stroke cylinder for clamping
the moulds.
It is often difficult to justify upgrading hydraulic systems and components based on energy
savings alone. Improvements in productivity, quality, as well as decreased maintenance
costs, must also be considered.
As a rule, retrofitting older existing equipment may not be effective if the machines are
small or modifications are not easily made. Buying new equipment with energy-efficient
components, controls and mode of operation may be more cost-effective. It is important
to ensure that the energy penalty from older technology is understood and that the
implications are considered when future equipment purchasing decisions are made. If
there are several machines available for production, it would be beneficial to consider
using the most energy-efficient equipment if production schedules permit.
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6.2.7 MACHINE COMPONENTS
68
It is important to replace worn out components, such as valves, with more efficient products.
On injection-moulding machines with vane-type hydraulic motors, efficiency decreases
if the motor is run at less than 80 percent of rated speed. To improve speed range, install
a two- or three-speed gearbox. Alternatively, replace the vane hydraulic motor with a
direct-coupled-piston type of hydraulic motor, which is efficient over the entire speed
range. A more expensive option is to install an electric variable-speed drive. The cost
of power electronics have declined; and under some circumstances, this option may be
economically viable.
6.2.8 SCREWS AND BARRELS
A high percentage of the total energy requirement (up to 30 percent) for moulding and
extrusion equipment is used to plasticize material. Screw design is the most important
feature on extrusion/injection machines. Screw design technology is constantly evolving
and many vendors can provide information on the appropriate screw diameter, geometry
and length-to-diameter ratio appropriate to a specific material and plasticizing rate. Energy
savings of 20 percent are claimed in some instances. If the machine use rate is high and the
production demands are predictable, a screw replacement may be warranted. Screws and
barrels should be checked every five to six months. Replace or repair worn screws as the
payback is quick (i.e. a few weeks).
Heater bands account for approximately 14 percent of the energy used. It is recommended
that the barrel be properly insulated, which will result in both energy savings and a more
easily controllable melt temperature. Insulation should not be used over mica heater bands
as the insulation will reduce their operating life.
6.2.9 ENERGY MANAGEMENT PRACTICES
For plastics processors to achieve and sustain energy-cost reductions, they need to
consider a systematic or continuous improvement approach to managing energy. The
energy-conservation opportunities (which are largely technical in nature) described
throughout this guide are important considerations in the effort to reduce resource
consumption, but attention to the energy management practices that support those
improvements will become more important over time (see Figure 6-3).
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Figure 6-3 Energy Savings Potential Versus Time
69
Available Savings
Becomes more difficult
to generate savings
Becomes more
important to tackle
Time
Technical
Management
The 10 key areas of an energy management program are described below:
•
Leadership – A feature of successful management programs is commitment and
leadership from top management. This means that senior management, right through
to CEO and Board-level, set the direction for energy management, demonstrate that
“energy management matters” in the organization, communicate this effectively, and
ensure that results are achieved.
•
Understanding – A formal approach to quantifying the main areas of energy use and
identification of opportunities for savings. Conducting an energy baseline study of
operations from a comprehensive perspective may give the organization insight into
opportunities for cost control beyond the already-captured “low-hanging fruit.”
•
Planning – Planning is an essential element of any effective change process. The planning
process should outline specific short-term (90 day) and longer-term (2 to 3 years)
actions with defined objectives. A well-documented energy management plan will
help maintain focus and realise early (and visible) benefits from energy management.
•
People – Having a well-trained staff of people that are aware of energy management
issues and are accountable for achieving energy reduction targets is a critical component
of an energy management program.
•
Financial Management – Capital and operating budgets should be reviewed in relation
to energy management. Return on capital invested in energy efficiency efforts should
include consideration of the life-cycle operating costs of the buildings or equipment.
Procedures and incentives should be put in place to ensure that energy efficiency
investments are evaluated consistently and accurately.
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•
Supply Management – On a regular basis, plastics processors should assess how energy
is purchased in a competitive market, as well as reviewing mechanisms employed, to
ensure a high level of quality and reliability.
•
Operations and Maintenance – Making operations personnel aware of the required
energy efficiency parameters by incorporating the parameters into operating procedures
and work instructions, as well as including effective energy efficiency measures as part
of standard maintenance program, are key components in sustaining energy cost savings.
•
Plant and Equipment – A feature of a well-developed energy management process is
established guidelines for new designs and innovations to enable energy efficiency to
be optimised throughout a plastics processing facility.
•
Monitoring and Reporting – Plastics processors should ensure that the right energy
flows are metered and usable reports developed to track and proactively manage energy.
•
Achievement – It is important to review implemented projects to ensure that the
original objectives are achieved, to feed back results, and to make any necessary
adjustments for varying processes or activities. Not only will such reviews ensure
greater savings, the results can be used to develop and implement future
improvement projects or processes.
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Several sources are available to help plastics processors develop their energy management
practices and establish a continuous-improvement program. Relevant links are provided below.
6.2.9.1 Sources for Energy Management Program Development
A copy of CIPEC’s Energy Efficiency Planning and Management Guide is available at
oee.nrcan.gc.ca/industrial.cfm.
Information on the ENERGY STAR® Program of the U.S. Environmental Protection
Agency is available at www.energystar.gov/index.cfm?c=guidelines.download_guidelines.
6.3 WATER CONSERVATION
For processors who use significant amounts of process-cooling water, the following system
design considerations and calculation formats may be used to evaluate the savings available
from a variety of recirculating systems, versus using line water on a once-through basis.
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6.3.1 SYSTEM DESIGN CONSIDERATIONS
71
Government statistics indicate that the plastics processing industry recirculates approximately
87 percent of its water requirements. This chapter will assist processors who are using
cooling water on a once-through basis to evaluate the savings opportunities available for
their process. The potential for cost savings depends on several factors such as:
•
the amount of water used as once-through, non-contact cooling water
(m3/h or gallons per minute);
•
the associated cost of cooling water – water costs involve both the cost of the supply
water, and the sewer discharges associated with disposing of the water. (The water
costs in Canada vary between $0.38/m3 to $1.01/m3);
•
the heat load of the operating equipment based on hours per year;
•
the cooling water temperature required;
•
capital cost of the cooling water recycle system;
•
operating cost of the cooling water system; and
•
cost of make-up water.
The water must truly be “non-contact” water for it to be recycled. Quite often a “blowdown”
stream and chemical additives are required to control water pH, hardness, bacterial growth
and suspended solids. This blowdown stream would be pumped to a sewer and, therefore,
a small amount of make-up water is required. The amount of blowdown and make-up in
this system should be minimal and will vary with every system.
The following are three basic cooling systems that can be implemented:
1. Portable chiller for small heat loads
(1–9 tonnes heat load)
2. Permanent chiller or cooling tower
for medium heat loads
(9–36 tonnes heat load)
3. Permanent chiller and cooling tower
for large heat loads
(36+ tonnes heat load)
Medium-heat load applications may be able to use a chiller or a cooling tower, depending
on the process and the volume of water and cooling water temperature required. A situation
with high cooling water temperature, but low cooling-water volume requirements, may
suit a cooling tower system. This is due to the high operating costs of a chiller, which
would offset the savings in water use costs.
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6.3.2 CALCULATIONS
72
Cooling Water Use and Heat Load
The following section allows you to calculate the cooling water heat load.
Type of cooling:
Cooling water flow rate:
m3/h
Temperature of cooling water required:
°C
Temperature of cooling water after the cooling application:
°C
Difference in temperature (T) = Temperature of cooling water – Temperature
required after the cooling
of cooling
application
water
=
°C –
=
°C
°C
Heat load (tonnes) = [Flow rate (m3/h) x T (°C)] / 3
(m3/h) x
=[
=
(°C)] / 3
tonnes
Water Costs
This section allows you to calculate the annual water costs spent on cooling water.
Municipal water costs = $
/m3 (including sewer surcharge)
Amount water used per year =
x
weeks/year
=
m3/h x
hours/day x
days/week
m3/year
/m3 x
Annual cost of water = $
m3/year
Chiller Costs and Payback Period
Look at the heat load (tonnes) calculated above to determine the type of chiller most
appropriate to the application from the information in Table 6-2.
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Table 6-2 Appropriate Cooling Systems for Determined Heat-Load Ranges
73
Heat Load
(tonnes)
Chiller Type
1–9
Portable Chiller
9–36
Permanent Chiller or Cooling Tower
36+
Chiller and Cooling Tower
Examples of heat loads, energy requirements and chiller types can be seen in Table 6-3.
Table 6-3 Examples of Heat Loads, Energy Requirements and Chiller Type
Heat Load
(tonnes)
Chiller Type
Energy Requirement
Portable Chiller
14.0 kW
27
Permanent Chiller
45.9 kW
27
Cooling Tower
6.5 kW
90
Chiller and Cooling Tower
62.5 kW
6.75
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Net Savings
This section will allow you to calculate the net savings for implementing a cooling
system. As discussed above, the cost of make-up water should also be considered.
Use the following formula to calculate the approximate energy costs per year.
Base energy cost = $/kWh
(approximately $0.08/kWh)
Electrical energy requirement =
kW (from table 6.3)
Energy cost = Base energy cost x Electrical energy requirement x Hours of
operation/year
= $/kWh
=$
x
kW x
hours/day x
days/week x
weeks/year
/year
Net Savings = Annual cost of water – [(Chiller operating cost) + (Make-up water cost)]
Payback Period
This section will allow you to calculate the simple payback period on the cooling system.
Payback period = Approximate cooling system cost / Net savings
=$
=
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6.4 AUXILIARY SYSTEMS AND FACILITY EQUIPMENT
75
This section addresses significant opportunities related to auxiliary system efficiency.
Table 6-4 contains excerpts from the CIPEC studies. It illustrates savings opportunities
for various auxiliary systems.
Table 6-4 Energy Savings Potential in Auxiliary Systems
Auxiliary System
Energy Saving Technique
Potential
Saving %
Material dryers (electrical)
Use high-efficiency electrical dryers.
30
Material dryers (natural gas)
Use gas-fired dryers for high-volume applications
(typical for polyethylene terephthalate).
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Install dew point monitors on dryers.
20
Ensure system is correctly sized and well managed.
If capacity is sufficient, stage compressors.
20
Dew point monitoring
Air compressor operation
6.4.1 DRYERS
To provide good drying conditions, a dryer should provide the following: adequate drying
temperature and dew point for the quantity of air used; adequate residence time for all the
resin passing through the hopper; and good air-flow distribution through the hopper.
Gas-Fired Dryers
Several manufacturers offer modular, natural-gas-fired dryers and claim energy cost savings
from 60–80 percent over electric systems. Gas-fired heaters may also be retrofitted to
existing electric dryers at about 50 percent of the original price. Mechanically, the units
are virtually identical to electric dryers. However, heat exchangers may be employed
to maintain proper moisture levels to compensate for water that is generated in the
combustion of gas. While capital costs may be higher than electric dryers, manufacturers
claim payback periods averaging about 12 months for high-volume applications.
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Two-Stage Dryers
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Two-stage systems, which incorporate a drying oven and a dehumidifier, may be used to
dewater hygroscopic resins while raising their temperature for subsequent melt processing.
Manufacturers claim such systems are energy efficient, especially if waste heat from one
dryer is reclaimed through a heat exchanger and re-used in the second. Two-stage systems
can extend the life of dryer components (such as the desiccant in the second-stage dryer).
Smaller Heaters
Instead of central-heating systems, smaller, independently controlled heater elements may
be installed in each drying bin, avoiding energy loss along pipelines or conduits. Other
systems combine drying and conveying into a single unit.
Microprocessor Controls
Drying is another area where the application of microprocessor control can result in significant
process improvements. Dryers are often operated at less than their maximum-rated capacity
using more energy than required to remove moisture. With recently developed microprocessor
control, temperature and dew point sensors installed at strategic locations in each dryer
provide data input to a drying profile programmed for the specific resin being processed.
The target profile automatically controls hot air flow, triggers replacement of desiccant
cartridges and maintains the dew point and drying temperatures to optimize the actual
material throughput and the drying conditions in the unit. However, at its present level
of operational reliability, it is wise practice to supplement microprocessor control with
periodic manual checks to ensure proper operation.
Insulation
The hopper or drying bin, as well as any connecting hot air conduits, may be enclosed in
an insulating blanket to prevent heat loss.
Energy Recovery
The heat from the exhaust side of drying bins can be recovered through a heat exchanger
and used for general plant heating, preheating incoming air, preheating material sent to an
extruder, or heating material in other drying/dehumidifying bins.
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6.4.2 ELECTRICAL SYSTEMS
77
The potential energy savings from correctly specified motors has been discussed above.
Further opportunities may be found by examining the plant electrical demand as a whole.
The plant electrical costs are usually based on:
•
peak electrical demand (kW);
•
energy consumption (kWh); and
•
power factor penalty.
The peak demand often occurs at a predictable time of day and may be reduced by
shutting off non-essential equipment during that period, re-scheduling operations or
by improving the efficiency of the operation. Reduction of consumption is discussed
elsewhere in this guide.
A poor power factor is typically caused by under-loaded AC induction motors, transformers
and lighting ballasts. Utilities usually charge a power factor penalty to customers whose
power factor is less than 90 percent. The common cost-effective solution for power factor
correction is the addition of capacitors to the system.
6.4.3 COMPRESSED-AIR SYSTEMS
The following suggestions will help to increase the efficiency of compressed-air systems
and to reduce the cost and consumption of compressed air:
•
Avoid air leaks – Even a small leak generates significant costs; an annual survey and
repair of leaks almost always pays for itself within months.
•
Operate at the lowest-possible pressure – Look for ways to lower system pressure:
if you have a specific piece of equipment that needs a higher pressure, consider using
a booster at the point of delivery as opposed to setting the entire system pressure to
feed the highest pressure requirement.
•
Optimize system size – Do not oversize compressors: use adequately sized piping to
reduce pressure drops, provide adequate storage (rule of thumb: 3 gallons per cubic
foot per minute to be delivered).
•
Avoid water accumulation in the system – Water causes corrosion on the inside
of compressed-air lines and decreases efficiency of the entire system.
•
Draw cool air from outside the plant – The cooler the air, the lower the moisture
content and the higher the density, making it more easily compressible.
•
Use engineered nozzles – Blow-off applications using engineered nozzles can use
up to 85 percent less air than a copper tube or open line. Engineered nozzles can
pay for themselves in a very short period of time.
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Decide on a control strategy for multiple compressor units – Investigate installing
a control system that will sequence units based on pressure requirement and operating
priorities. In some cases a variable speed drive on one of the compressors can be an
easily justified investment.
Additional information on optimizing the efficiency of compressed-air systems is available
at the Compressed Air Challenge® (www.compressedairchallenge.org) – a U.S.-based
voluntary collaboration of industrial users, manufacturers, distributors and their associations,
energy efficiency organizations and utilities.
6.4.4 LIGHTING
The following guidelines will assist in reducing electrical demand in lighting systems:
Reduce the number of fixtures to a level that is adequate to the job
Historically, many lighting systems have been over-specified. A reduction in the number of
fixtures, bulbs or tubes will often reduce energy costs, while maintaining adequate lighting
levels. Surplus ballasts should be removed if fewer fluorescent fixtures are required; ballasts
draw energy even when the fluorescent tube is removed.
Use more efficient technology
Replace existing incandescent lamps with high-efficiency fluorescent, halide or high-intensity
discharge lamps. Fluorescent lamps are typically 1.5 to 2 times as efficient as incandescent
and high-pressure sodium lamps are 1.5 to 2 times as efficient as fluorescent lighting.
Table 6-5 provides an outline of operating costs (at $0.08/kilowatt hour), electrical
consumption and light output data for various lighting types. The tabulated data include
ballast contributions.
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Table 6-5 Light Source Efficacy
79
Lighting Type
Annual Cost
($/bulb/
shift/year)
Bulb Wattage
(watts)
Light Output
(lumens/
watt)
4-ft. Std. Fluorescent (T12)
w/Std. Magnetic Ballast
7.4
46
58
4-ft. EE. Fluorescent (T8)
w/Electronic Ballast
5.0
31
83
14.1
88
70
8.5
53
102
8-ft. High Output Fluorescent
(T12) w/Std. Magnetic Ballast
20.6
129
65
8-ft. High Output EE. Fluorescent
(T8) w/Electronic Ballast
12.8
80
100
400 W High-Pressure Sodium
74.4
465
97
400 W Metal Halide
72.8
455
63
400 W Mercury Vapour
72.0
450
40
8-ft. Std. Fluorescent (T12)
w/Std. Magnetic Ballast
8-ft. EE. Fluorescent (T8)
w/Electronic Ballast
Lights should be turned off when not required
Timers, occupancy sensors or photocells will assist in reducing energy costs by turning off
or dimming lights. As a general rule, incandescent lights should always be turned off when
not required, fluorescent lights when not required for more than 15 minutes, and halide
or high-intensity discharge lamps if not required for more than one hour.
Some additional factors to consider are the following:
•
Lighting energy is wasted when there are no local switches.
•
Activities requiring high visibility or colour resolution require task lights.
•
Excess lighting levels are counter-productive, waste energy and can harm eyesight.
•
Day-lighting is better than artificial lighting in that it is less expensive and emits
less heat.
•
Lighter, reflective ceiling, floor and wall colours require less lighting.
•
Multiple lighting levels (ambient and task) save energy.
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Examples of ambient lighting levels are:
-
Office – 30–50 FC (300–500 lux)
-
Laboratory – 30–50 FC (300–500 lux)
-
Production – 50–75 FC (500–750 lux)
Additional information on optimizing lighting in manufacturing facilities can be found at
www.iesna.org.
6.4.5 PROCESS INSULATION
Thermal insulation on process equipment and piping has the following benefits:
•
prevents heat loss;
•
assists in maintaining consistent process temperatures;
•
prevents condensation; and
•
assists in maintaining a comfortable and safe workplace.
6.4.6 BUILDING HEATING, COOLING AND VENTILATION
Many plastic processes and auxiliary systems emit heat. It is sometimes cost-effective to
capture process heat with suitable heat exchangers, or to blow heated air from areas such
as a compressor room and to use this waste heat to supplement facility-heating requirements.
Thermostats may be programmed to reduce the heating load during off hours. Other cost
saving methods include the following:
Reducing excess air infiltration
•
Improve caulking and weatherstripping around doors and windows.
•
Install air locks and air curtains.
•
Install low leakage dampers.
Adequate ventilation may be obtained by following the guidelines published by the
American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE).
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Destratification
Energy savings may be achieved during the winter heating season by preventing stratification
(the tendency for warm air to rise and collect near the ceiling) in the following ways:
•
install ceiling fans;
•
introduce make-up air near the ceiling level; and
•
use radiant heating.
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Additional information on heating, ventilating and air-conditioning (HVAC) system
optimization and energy efficiency is available at www.aceee.org/ogeece/ch3_index.htm.
6.5 EMISSIONS REDUCTION
The reduction of emissions from plastics processing operations is best achieved through
carefully designed programs to optimize all aspects of the manufacturing process, particularly
with respect to the use of raw materials including energy and water. Continuous improvement
is best achieved through the implementation of an effective environmental management
system. In addition to further discussion on this system, other energy improvement opportunities
are also discussed that will focus specifically on material conservation, energy conservation,
water conservation, auxiliary systems and facility equipment, and case studies relevant to
the plastics processing sector.
6.5.1 AIR RESIDUALS – GASES AND DUST
Greenhouse gas emissions, principally CO2, can be reduced by ongoing improvements in
energy efficiency. Improvement opportunities are outlined in Section 6.2, “Energy Conservation.”
These have the dual effect of both improving energy efficiency and reducing CO2 emissions
per unit of product processed.
6.5.1.1 Volatile Organic Compounds Reduction
The following strategy has been endorsed by three of the four groups mentioned in
Section 2.5.1.1 (the PVC working group has yet to develop a strategy relevant to its sector).
For new or modified facilities, the working group proposed to adopt the Canadian Council
of Ministers of the Environment (CCME) Environmental Guideline for the Reduction of
Volatile Organic Compound Emissions from the Plastics Processing Industry, published in
July 1997. This guideline provides standards and guidance for the reduction of VOCs in
new or modified facilities.
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For existing facilities, the plastics processing working group supports the application of
BACTEA (Best Available Control Technology Economically Achievable), as recommended
in the 1990 CCME NOx/VOC Management Plan. The working group proposes to work
toward the adoption and implementation of the CCME guideline for VOC reductions in
existing plastics processing facilities where possible, and under BACTEA conditions. This
would involve the adoption of the CCME guideline provisions relating to, for example,
equipment and operating standards, and training and record keeping.
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The following are additional highlights of the VOC emissions-reduction initiatives
specifically proposed for each sub-sector group relating to existing facilities:
Composites: The industry is committed to achieving the tenets outlined in the CCME
document. CPIA is planning educational packages to provide the hundreds of Canada-based
fabricators the means of reducing emissions containing VOCs. The instructional guidelines
are intended to provide a basis for implementing consistent and uniform control measures
and industrial operating standards. The guidelines focus on the reduction of VOC emissions
from processing and cleanup operations, the handling and storage of VOC-containing
materials, and the handling and disposal of waste.
Resin suppliers, on average, have already achieved the reduction in styrene monomer content
from 48 to 45 percent for general-purpose resins. Secondly, the industry in Canada has
seen a dramatic shift from open-moulding to closed-moulding operations. This trend will
continue across North America in the coming decade. It is estimated that there will be a
further 10 percent reduction in open-moulding operations resulting in a further 10 percent
reduction in VOC emissions prior to any further reduction in styrene monomer content.
EPS Foam: The industry will continue to move toward processing low-pentane content
resin as it becomes available in the marketplace. The aim is to achieve the CCME target of
5 percent VOC content by weight of resin consumed on an aggregate basis where economically
feasible. The sector will use recycled material content, where possible, to displace raw materials
that have a higher pentane content. As well, existing facilities will focus long-term capital
plan objectives on replacing existing process equipment with equipment capable of processing
low-pentane resin.
PE Foam: The industry will proceed on two parallel fronts. First, the industry will secure
the acceptance and funding to pursue research into an alternative-blowing agent. Second,
the industry will further investigate possible methods to reduce the percentage of butane
used in production.
Vinyl: The group has not yet launched into the development of a reduction strategy. The
group has indicated, however, that the application of inks in printing causes more VOCs
than processing using calendering. A major company processing calendered vinyl is part of
a separate working group established to address VOC emissions from printing operations.
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General Recommendations
Care must be taken to ensure that resin manufacturers’ recommended processing temperatures
are not exceeded. Vendors’ material safety data sheets should be consulted for appropriate
processing procedures, precautions and engineering controls. For many materials, local
exhaust hoods are recommended near areas where materials are heated.
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It is good management practice to conduct periodic air sampling surveys within the plant.
Air sampling surveys serve the dual function of identifying air emission issues that may
need to be addressed and also indoor plant air quality issues in relation to the Canada
Occupational and Health and Safety Regulations.
6.5.1.2 Dust Reduction
Fugitive dust levels may also be reduced through the use of collection systems located
close to key locations within facilities, such as material handling areas and locations
dedicated to blending and grinding operations.
6.5.2 WASTEWATER AND LIQUID WASTES
The recirculating of cooling water has been discussed in a previous section.
The discharge of wastewater to a sanitary sewer system is regulated under municipal
by-laws. To minimize the risk of contaminating wastewater discharges, engineering
controls and a spill prevention plan should be put in place. Typical preventive measures
include the following:
•
oil interceptors for plant discharges;
•
blocking building drains in areas where spills are likely; and
•
secondary containment for storage tanks.
Good housekeeping practices will reduce the introduction of particulates into the sanitary
sewer system. Properly engineered oil separators should be installed if oil spills are likely.
Whenever possible, floor drains within the plant should be capped or sealed to contain
minor spills.
Secondary containment should be provided for storage tanks containing petroleum
products or hazardous chemicals.
Liquid wastes that require special handling and are commonly generated by the plastics
processing industry include used hydraulic oils, spent solvents and other chemicals that
should be properly stored and disposed of in accordance with provincial regulations.
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GENERIC IMPROVEMENT OPPORTUNITIES
Municipalities regularly sample plant discharges. However, they often fail to inform the
manufacturers of exceedances; it is incorrect to assume that the operation is in compliance
if no complaints are received.
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6.5.3 SOLID WASTE
Source separation programs should be instituted for cardboard, steel, fine paper, glass and
corrugated cardboard. Many companies already recycle packaging materials. Used gaylords
are in demand by many industries for use as storage containers.
A number of Canadian firms specialize in recycled plastic materials. Clean pellets or regrind
may be sold to these companies for re-pelletizing or re-sale.
6.5.4 NOISE
A noise survey should be conducted to identify areas that may exceed Occupational Health
and Safety Regulation limits. Engineering controls should be used to reduce noise levels,
whenever possible. Personal protective equipment must be supplied if controls are not
feasible and should be provided in areas where employee comfort can be increased.
6.5.5 STORMWATER
Stormwater, if it is discharged into a ditch or another “surface watercourse,” may fall
under federal or provincial/territorial jurisdiction. The limits on contaminants are typically
more strict than for sanitary sewers. A stormwater management plan should be in place to
reduce the risk of contamination.
6.6 ENVIRONMENTAL MANAGEMENT SYSTEMS
Well-designed environmental management systems (EMSs), such as ISO 14001 and
resource conservation programs, will assist processors to achieve the objectives of
minimizing the impact of plant operations on the environment and reducing costs.
An EMS is that aspect of an organization’s overall management that addresses the immediate
and long-term impact of its products, services and processes on the environment.
An EMS is essential to the organization’s ability to anticipate and meet growing
environmental performance expectations and to ensure on-going compliance with municipal,
provincial/territorial, national and international requirements. Evidence of an effective
EMS has become an important part of obtaining corporate financing and helps to maintain
real estate property values.
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The ISO 14001 EMS standard provides an internationally recognized structure for developing
and maintaining environmental systems. In many ways, it complements the well-known
ISO 9000 series of quality standards.
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ISO 14000 series standards involve the elements listed below (many of these standards are
still under development):
•
Environmental Management Systems
•
Environmental Performance Evaluations
•
Environmental Auditing
•
Life-Cycle Analysis
•
Environmental Labelling
•
Environmental Aspects in Product Standards
A detailed listing of the ISO 14000 series standards can be found in Appendix II.
Setting up and Managing an Environmental Management System
The effectiveness of an EMS may be improved by applying the following common
management principles, which can contribute to the success of any project:
•
top management commitment;
•
clear definitions of responsibility and accountability;
•
well-defined, realistic goals; and
•
effective program planning and implementation.
Most successful programs start with an audit. The audit determines how the environment
is impacted by plant activities, how resources are being used, and identifies possible
opportunities for improvement and for savings. Some plants have the internal resources to
conduct an audit. Assistance and publications are available from utilities and government
sources. If the environmental impacts are significant, if resource consumption is high or if a
preliminary assessment shows significant savings potential, the opportunity may be pursued
by using internal resources or with the assistance of a consultant specializing in the field.
A reduction in the use of resources supports the objectives of an EMS. Lower resource use
typically has a favourable impact on reducing environmental effects.
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86
Vinyl Council of Canada
Environmental Management Program
Members of the Vinyl Council of Canada (VCC) recognized the need to demonstrate their
commitment to not only complying with environmental health and safety laws, but to
being more accountable and responsive to society’s evolving concerns. The VCC also felt
that it was important that their actions be documented and measurable. In 2000, the
VCC began implementation of its Environmental Management Plan (EMP), which had
been developed over the previous two years. The EMP consists of six guiding principles, five
commitment areas and 32 action steps, which are outlined in the following table.
Principles
Commitment Areas
# of Action Steps
Development of
Mutual Trust
Management Commitment,
Implementation and Review
11
Environmental
Management System
Operations
7
Integration of Priorities
Resource Conservation and
Waste Management
4
Compliance Plus
Product Stewardship
5
Sharing Expertise
Communications
5
Continuous Improvement
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6.7 CASE STUDIES IN RESOURCE CONSERVATION
87
There are a wide variety of case studies available that demonstrate successful resource
conservation efforts. The following summaries of case studies show some of the successes
achieved by plastics processors who have applied specific resource conservation measures.
Energy Conservation
•
An Ontario vinyl siding manufacturer recently saved about 10 percent of its energy
costs by undertaking a series of process changes and other initiatives. Many of the
changes were direct suggestions from employees.
•
A mid-sized processor of flexible vinyl undertook an $8,000 energy audit (of which
50 percent was government-funded) and identified $80,000 in annual savings.
•
Improving Energy Efficiency at U.S. Plastics Manufacturing Plants – this document
was prepared by The Society of the Plastics Industry, Inc. and the U.S. Department of
Energy. It is an excellent Summary Report and reproduction of 11 case studies. The
case studies highlight energy savings opportunities identified and implemented at U.S.
plastics manufacturing facilities. The site assessments were carried out in 2003, and
the report summarizes the implemented total savings as of March 2005. For the 11 sites,
the overall annual average cost savings identified was $149,253 per site. Implemented
total annual cost savings averaged $68,454 per site as of March 2005. The implemented
total annual cost savings represents about 10 percent of the annual energy costs for
the 11 sites. The key areas identified for improvement in the assessments included
improvements to water cooling systems, reducing changeover times at presses, HVAC
improvements, motor management systems and insulation. A selection of sample case
studies from the above-noted report is provided in Appendix IV.
A copy of the full Summary Report and individual case studies can be downloaded at
www1.eere.energy.gov/industry/bestpractices/plastics_manufacturers_save.html.
•
Corporate Energy Management at C&A Floorcoverings – Collins & Aikman (C&A)
has implemented a management system for matching energy efficiency initiatives
with business goals. After two years, C&A achieved 10 percent savings on an annual
natural gas expenditure of $824,500. The full case study can be reviewed at
www.ase.org/uploaded_files/industrial/CollinsAikman%20v04.pdf.
•
Industry Energy Services Program Summary – information from energy audits of
67 Ontario plastics processing facilities conducted by the Ministry of Environment
and Energy (now Ministry of the Environment) from 1985 to 1997, are found in
Appendix I. The study demonstrated rapid paybacks from improved technology and
from heat recovery.
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Water Conservation
88
•
A blown film manufacturer in Atlantic Canada saved over 85 percent of its water
throughput by introducing a closed-loop cooling system. This same company
reduced its waste by 20 percent while growing the business by 15 to 20 percent.
•
New United Motor Manufacturing, Inc. – a water conservation program resulted
in savings of more than 270,000 gallons per day. By installing re-circulating pumps
in the evaporative air conditioning system and recycling process water, the company
conserves enough water, daily, to supply 2,000 houses. The case study can be viewed
at www.stopwaste.org/docs/nummi.pdf.
Environmental Management Systems
•
Van Dorn Plastics Machinery Company, Strongsville – This U.S. manufacturer
reduced waste generation by more than 35 percent despite increasing production
volumes. Its highly participative Pollution Prevention Pays program was developed
as a part of its Total Quality Management initiative. This case study is available at
es.epa.gov/techinfo/case/comm/vandorn.html.
Waste Management Systems
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An injection-moulding operation in Toronto undertook a waste audit and has saved
$30,000 from source separation. The company now moves “clean” materials to recyclers,
therefore eliminating the disposal fees.
•
A company in New Zealand arranged to take delivery of plastic waste and even
obsolete products created by its customers. While this started as an environmental
initiative, it has resulted savings of NZ$250,000 per year and has solidified
relationships with customers. This company now designs its products with disposal
in mind.
ENERGY EFFICIENCY OPPORTUNITIES
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CANADIAN PLASTICS PROCESSING INDUSTRY
7
NEW AND EMERGING
TECHNOLOGIES
7
NEW AND EMERGING TECHNOLOGIES
7. NEW AND EMERGING TECHNOLOGIES
90
Many facets of plastics processing and related manufacturing technologies evolve continuously.
New and modified materials and end-use applications are introduced on an ongoing basis.
However, unless a new processing technology represents a quick payback on capital investment,
it would be expected to penetrate the industry slowly. Despite significant investments in new
equipment by many manufacturers in the last few years, a significant portion of machinery
in the plastics processing sector is several decades old. This chapter discusses technologies
that are developed, but which have not yet enjoyed full acceptance by the industry.
7.1 RAW MATERIAL DEVELOPMENTS
The existing variety of plastic raw materials available to the processor is large and yet still
growing. Materials for high-volume applications undergo an ongoing development process
in an attempt to improve product performance and ease of processing and to reduce cost.
Vendors attempt to increase their market shares by replacing competing plastic resins
currently in use and by supplanting other materials.
In the last few years, a new family of metallocene-catalyzed plastics has been introduced.
The excellent physical properties of these materials are expected to lead to increasing use
in applications such as co-extruded packaging for food wrap or as a modifier of other
materials as agents that improve clarity.
7.2 ROBOTICS
Robotics are used to improve machine speed, reduce costs, increase safety and improve
quality by maintaining consistent machine cycles.
The most common and simple robotics application is a sprue picker, which is used to
ensure positive removal of the sprue from an injection mould. More advanced uses include
parts removal and packaging from multiple cavity moulds, especially in applications where
products could be damaged by handling or where maintaining correct orientation of the
parts is important.
Another important use of robotics is to place metal inserts into moulds. The accurate
positioning of inserts is critical. In some instances, the loading of inserts manually could
also pose a safety hazard to the operator.
Some blow-moulded applications (e.g. pesticide containers) require moulded-in labels to
ensure that the labels remain in place. Robots are used to place labels into blow moulds
during the operating cycle.
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7.3 ALL-ELECTRIC INJECTION-MOULDING MACHINE
91
The majority of injection-moulding machine manufacturers currently produce a line of
entirely electrically operated machines, without hydraulics. Some of the major advertised
advantages over conventional machines are as follows:
•
More efficient use of energy – Energy savings of more than 50 percent are claimed
over conventional hydraulic presses. Motors are sized for the application, fully speed
adjustable and only operate when required.
•
Quiet, clean, compact operation – Manufacturers claim noise levels in the 73 decibel (dB)
area, versus 78 dB for conventional machines. (A 10-dB reduction is generally perceived
as a 50 percent reduction in noise levels.) This makes the machines quiet enough to
operate in an office environment. Electric machines also eliminate oil mist problems.
The machine footprint is also smaller than conventional machines of an equivalent size.
•
Better control of process – More precise and repeatable control results in faster set-ups
and better adherence to tolerances. Manufacturers are suggesting that the repeatability
and reliability of electric-moulding machines will make unattended “lights out”
operation a realistic possibility.
•
Hydraulic oil related issues eliminated – No need to replace or dispose of
hydraulic oil. Also, machine-cooling requirements are eliminated.
•
Faster response time (cycle time) – The reaction time of electrical controls is quicker
than electrical/hydraulic units.
Initially, all-electric machines came at a premium of approximately 30 to 50 percent over
conventional hydraulic machines. The premium is now estimated to be in the 20 to 30 percent
range as the initial development costs have partially passed. Available data on market volume
of all-electric machines in the U.S., Asia and Europe are presented in Figure 7-1.
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NEW AND EMERGING TECHNOLOGIES
Figure 7-1 Market Volume for All-Electric Machines in Units
92
3,000
2,500
2,000
Units
7
1,500
1,000
500
0
1998
1999
U.S.
Asia
2000
Europe
Source: Canadian Plastics, December 2000
While the all-electric machine market is growing, it is still less than 10 percent of the new
injection-moulding machine market (46,000 machines in 2000). Even with the reduced
capital cost premium, the differential energy savings are not sufficient to produce a short
enough payback for most Canadian companies. Discussions with several plastics processors
in Canada indicate that the all-electric machines are being considered, but very few have
been purchased.
There are also hybrid machines available that consist of a hydraulic clamp with
electric screw drive and injection.
7.4 MICROWAVE DRYING
Microwave drying units that dry material using conventional microwave technology
and a variety of specific applications are still under development. The main advantage
of microwave drying is reduced drying time, allowing more rapid material turnover and
lower energy costs. However, the technology is capital intensive and prototype units are
batch-oriented while most processes use continuous feed systems. Further development
will be required to make microwave technology widely accepted for this application.
7.5 GRANULATORS
Manufacturers are developing special rotors or two-stage cutters that result in a lower
horsepower requirement and lower use of energy for a given throughput.
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7.6 RAPID PROTOTYPING
93
Historically, prototyping of components often necessitated the manufacture of steel moulds.
This is both time consuming and costly. Furthermore, design changes often meant that the
initial prototype mould had to be extensively modified or scrapped.
In recent years, the following technologies have been developed to produce prototypes
directly from computer designs, without the need for moulds:
•
Stereolithography – A prototyping process that uses a laser to deposit consecutive
thin layers of a polymer in solution. The layers are gradually built up to form a
model, which may be quite complex in configuration.
•
Selective laser sintering – Used to build up layers of material in a manner similar
to stereolithography with dry powdered materials, rather than liquid polymers.
•
Ballistic particle manufacturing – A recently developed prototyping method
that has adapted a technology similar to ink jet printing. Microscopic particles
of molten thermoplastic are “shot” with great accuracy to precise points to build
up a three-dimensional model.
7.7 GAS-ASSISTED INJECTION MOULDING
Designers of parts for injection moulding have historically been constrained by the need
to maintain relatively constant and thin sections in the finished products. This is because
thick wall sections, in addition to requiring a long cooling time, had a tendency to develop
sink marks – depressions in the part surface caused by the contraction of the plastic while
cooling. Gas-assisted moulding helps to overcome these problems and permits a broader
range of applications.
In this process, nitrogen gas is injected into the interior of the melt at the thick sections.
The gas pressure creates a hollow area within the plastic and forces the solidifying plastic
against the mould. This eliminates sink marks and reduces raw material cost. For certain
parts, material savings of up to 50 percent have been reported.
7.8 CO-INJECTION MOULDING
Co-injection moulding provides another method for improving physical properties and/or
reducing raw material costs. This process allows for two dissimilar materials to be injected
simultaneously through concentric nozzles. The designer of the part has the latitude to design
parts with an outer skin made of a material with the desired visual or physical properties
and to inject an internal core with a material that is less expensive, stronger or lighter.
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NEW AND EMERGING TECHNOLOGIES
7.9 TOOLMAKING TECHNOLOGY
94
Computer Assisted Design and Computer Assisted Manufacturing technologies continue
to have an increasing importance in shortening lead times and reducing tooling costs.
Digitized information is routinely transmitted from customer to tool vendors and is used
directly to guide toolmaking machinery, such as Numerically Controlled milling machines.
Electrical Discharge Machines (EDM) have largely replaced pantographs for making precise
tool cavities. Extrusion dies are manufactured using wire-cut EDM equipment to produce
complex configurations at a lower cost.
Potential exists for an increased use of superior mould alloys to reduce moulding cycles.
The majority of tool steels currently in use were developed prior to World War II.
7.10 VOLATILE ORGANIC COMPOUND (VOC)
CONTROL TECHNOLOGIES
There are various technologies available, some of which have been used by fabricators in
Canada for the purpose of reducing VOC emissions and VOC-containing materials used
in plastics processing operations. The main focus of efforts to date has been in the
implementation of processes and work practices leading to reductions in VOCs. Some
examples of control technologies currently available and/or under development are
as follows:
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•
Expanded polystyrene – Low-pentane beads have recently been made available by
one company while other companies are still in the research and development stages.
At this time, the use of a low-pentane bead is likely more suitable for medium- and
high-density products rather than low-density products such as insulation board.
As well, changes in equipment and processes are necessary in order to use the
low-pentane bead. Technology and capital cost implications must be considered
before this control technology can be used widely.
•
PVC – The trend in this sector continues to be the development of low-VOC
plasticizers. Other options include solvent-free stabilizers and low-VOC cleaners.
•
Reinforced plastics/composites (polyester resins) – Reduction options have focused
on the use of lower VOC materials and improving process efficiency through equipment
changes and good operating practices. Initiatives undertaken to date in the reinforced
plastics sector include the use of charcoal filters in stacks to reduce odour, VOC
emission levels and solvent use, and include the implementation of solvent recycling
programs consistent with the CCME guideline. In addition, in-house acetone recovery
programs have been implemented. Other reductions in VOC emissions can be
accomplished by undertaking the following: using low-styrene and wax-suppressed
resins and low-VOC cleaners, and by using high-efficiency spray applicators and
closed-moulding technology.
ENERGY EFFICIENCY OPPORTUNITIES
IN THE
CANADIAN PLASTICS PROCESSING INDUSTRY
NEW AND EMERGING TECHNOLOGIES
7.11 SYNCHRONOUS TORQUE MOTORS
95
Extruder equipment manufacturers are increasingly including synchronous torque (ST) motors
in their machine design. These motors are compact, very quiet, require little maintenance
and are energy efficient. Typically, an ST motor will use 10 to 20 percent less energy than
a direct current motor and 5 to 10 percent less energy than a three-phase alternating current
motor. They deliver constant torque over a wide speed range and possess high torque at
low speeds. The motors have been employed in commercial extrusion applications such as
tubing, blown film, sheet and continuous extrusion blow moulding. They have also been
used in downstream components such as chill rolls, winders and re-winders.
ST motors have been available for several years and are likely to be used increasingly
throughout the industry.
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8
BENCHMARKING
AND PERFORMANCE
MONITORING
8
BENCHMARKING AND PERFORMANCE MONITORING
8. BENCHMARKING AND PERFORMANCE MONITORING
98
Performance ratios are useful in assessing a facility’s efforts to reduce energy and water
use, and effluent discharges. Establishing a baseline measurement of resource consumption
and waste output allows a company to evaluate the improvements made in operations
and equipment over time. A series of generic formulae for calculating these ratios is
presented here.
For individual pieces of process equipment that are suspected of having significant potential
for improvement, it is possible to measure or calculate energy consumption and to develop
similar ratios. These can be compared to published data on more efficient equipment and
used to evaluate and prioritize energy improvement projects.
The following performance ratios calculate both the process and non-process consumption
of energy and water use (including utilities devoted to lighting, heating, ventilating and air
conditioning). All of these can be calculated directly from the company’s utility bills. Any
improvements made within a facility should result in a decrease in the ratio.
8.1 RAW MATERIALS USAGE
A key benchmark indicator is raw materials usage. Most facilities have the ability to calculate
expected or “standard” raw material consumption through the costing system. If the actual
consumption, obtained through purchase records, differs significantly from expected
consumption, this may be an indication of controllable losses and should be investigated.
Often, accurate data are available only after a physical inventory. These “raw material
variances” may indicate significant inefficiencies in material handling, scrap rates, set-ups,
or the process may also be used to identify unprofitable products.
As the resin processed in a specified period appears as the denominator in the following
calculations, it is important to define usage accurately. Preferably, the kilograms used
should be obtained from sales records to avoid counting scrap, purgings or other waste
as material “processed.”
8.2 UNIT ELECTRICAL ENERGY USE
The following formula is suggested for use in computing estimates of electrical energy use
per unit of plastics material processed at any given facility over any specified time period.
Total kilowatt hours electricity consumed x 3.6 = Unit electrical energy use in megajoules
Total kilograms resin processed
per kilogram
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8.3 UNIT NATURAL GAS ENERGY USE
99
The following formula is suggested for use in computing estimates of natural gas energy use
per unit of plastics material processed at any given facility over any specified time period.
Total cubic metres natural gas used x 37.2 = Unit natural gas energy use
Total kilograms resin processed
in megajoules per kilogram
8.4 REDUCTION IN CO2 EMISSIONS PER UNIT OF ENERGY
The following formula will provide an estimate of the amount of direct CO2 emission
reduction associated with a reduction in natural gas energy use:
Megajoules of natural gas energy reduced x 49.68 = tonnes CO
-equivalent emission reduction
2
106
Source: Environment Canada (1999), Canada’s Greenhouse Gas Inventory – 1997 Emissions and Removals
with Trends.
8.5 UNIT WATER USE
The following formula is suggested for use in computing estimates of water use per unit
of plastics material processed at any given facility over any specified time period.
Total cubic metres of water used = Unit water use in cubic metres per kilogram
Total kilograms resin processed
Benchmarking is a valuable tool for comparing performance between and among
manufacturing facilities. However, great care must be used to ensure that the data are
valid and comparable. For example, in the plastics processing sector, various processes
have a wide range of energy requirements. It is often difficult to find precisely identical
conditions in other locations and many companies are reluctant to share detailed
information with their competitors.
The Plastic Film Manufacturers Association of Canada and the Canadian Plastics Industry
Association (CPIA) publish financial and operating ratio results on an annual basis. These
surveys are available for purchase by members and non-members of CPIA. Information on
obtaining the survey is available on the CPIA Web site www.cpia.ca.
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8
BENCHMARKING AND PERFORMANCE MONITORING
Some companies have been successful in obtaining useful information on a reciprocal basis
from firms that produce similar or identical products for different geographical markets.
Raw material and equipment suppliers may be helpful in facilitating these contacts.
100
Benchmarking is an important tool for processors interested in the continuous
improvement of their processes and facility. Collecting the initial data and determining
appropriate ratios is the first step in the improvement process. It defines what parameters
are important and how they will be measured, which results in a starting point against
which improvements can be compared. Benchmarking focuses the processor on
improved performance and gives the organization specific goals to work toward.
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9
OTHER HELPFUL
INFORMATION
9
OTHER HELPFUL INFORMATION
9. OTHER HELPFUL INFORMATION
102
A series of additional reference materials about energy and environmental improvements
in plastics processing are described in the following section. In most cases, contacts are
provided for acquiring follow-up information.
9.1 MISCELLANEOUS REFERENCE MATERIALS
CIPEC Energy Efficiency Planning and Management Guide (Canadian Industry Program
for Energy Conservation [CIPEC]). This document describes the methodology for setting
up and running an effective energy management program, and provides worksheets for
evaluating the energy savings potential from improvements in lighting, electrical systems,
boilers, steam and condensate systems, heating and cooling, HVAC, waste heat recovery,
etc. Available on-line at www.oee.nrcan.gc.ca/industrial. For further information, fax the
CIPEC Secretariat at 613-992-3161, or send your request by e-mail to [email protected]
Operation Clean Sweep: A Manual on Preventing Pellet Loss (The Society of the Plastics
Industry, Inc.). This manual provides detailed guidance for minimizing raw material losses
in the plastics processing industry. The manual covers policies and procedures and recommends
a goal of zero loss of pellets. For further information, contact 202-974-5200, or visit
www.opcleansweep.org.
Natural Gas Applications for Industry, Volume VII: The Plastics Industry (American Gas
Association, 1992). This study examines cost-saving opportunities by using gas for a broad
range of processing technologies and ancillary equipment. Operating, technical and cost
considerations are discussed and the opportunities are ranked. The document provides
useful data and methods for assessing the cost-effectiveness of alternative energy inputs.
Visit www.aga.org/pubs.
Plastics Recycling: Products and Processes (Society of Plastics Engineers). A comprehensive
survey of the technical, business and environmental components involved in the recycling
of plastics (i.e. polyethylene terephthalate, polyolefins, polystyrene, polyvinyl chloride,
engineering thermoplastics, acrylics, commingled plastics, and thermosets). Visit
www.4spe.org
Environmental Guideline for the Reduction of Volatile Organic Compound Emissions
from the Plastics Processing Industry (Canadian Council of Ministers of the Environment
[CCME]). Nitrogen oxides (NOx) and volatile organic compounds (VOCs) react in the
atmosphere in the presence of sunlight to create ground-level ozone, a major component
of urban smog. This report results from a specific initiative under the CCME NOx/VOC
Management Plan, the overall aim of which is to reduce the formation of ground-level
ozone by controlling NOx and VOCs from a variety of new and existing sources.
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OTHER HELPFUL INFORMATION
This document will guide manufacturers and operators of plastics processing plants on how
to reduce VOC emissions from production, processing, cleanup, handling and storage of
VOC-containing materials, as well as on how to handle and dispose of wastes. It covers
production activities for a number of plastics: expanded polystyrene, cellular polyethylene
foams, polyvinyl chloride and thermoset polyester resins used in reinforced plastics and
composite products.
103
It also contains information on material, equipment, process and operating norms for
plastics processing facilities; norms for record-keeping and training; and recommended
operating practices and testing protocols. This document can be ordered from CCME
from its Web site at www.ccme.ca/publications.
9.2 PLASTICS PROCESSING INDUSTRY ASSOCIATIONS
Canadian Plastics Industry Association (CPIA)
The CPIA is the voice of the plastics industry in Canada. CPIA delivers its services
through regional offices and can be a valuable source in the areas of technology, trades,
health and safety, and the environment. CPIA is located at 5915 Airport Road, Suite 712,
Mississauga, Ontario, L4V 1T1. Telephone 905-678-7748, Fax: 905-678-0774. Visit
www.cpia.ca.
Environment and Plastics Industry Council (EPIC)
EPIC was formerly known as the Environment and Plastics Institute of Canada and is
now a Council of the Canadian Plastics Industry Association. It provides a wide range of
general information about integrated resource management and plastic solid waste issues.
Other resources include technical reports and information for solid waste managers about
plastics recycling collection and sortation methods. EPIC is located at 5915 Airport Rd.,
Suite 712, Mississauga, Ontario, L4V 1T1. Telephone: 905-678-7748, ext. 231,
Fax: 905-678-0774. Visit www.plastics.ca/epic.
Society of Plastics Engineers (SPE)
The objective of the SPE is to promote the scientific and engineering knowledge related to
plastics. This association holds an annual technical conference, which attracts a wide audience
interested in all technical aspects of the plastics industry. For information about the SPE,
call 203-775-0471 or visit www.4SPE.org.
9.3 INDUSTRY DIRECTORIES AND GUIDES
Recycling Markets and Recycled Products Directory (Environment and Plastics Institute of
Canada). Provides a listing and cross-indexing of the participants in all aspects of plastics
recycling in North America. The guide is available from EPIC at www.plastics.ca/epic.
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Industrial Programs Division (Natural Resources Canada, Office of Energy Efficiency [OEE]).
104
You can view or order several of the OEE’s publications on-line at
www.oee.nrcan.gc.ca/industrial.
Hydro One energy efficiency publications. The Hydro One Web site has a searchable
database of energy efficiency publications at www.hydroone.com.
9.4 ENVIRONMENTAL/RESOURCE AUDIT
GUIDANCE DOCUMENTS
Workplace Guide – Practical Action for the Environment (Harmony Foundation of
Canada, 1991). This guide was developed to introduce methods for implementing
environmentally sustainable practices in industry. It describes tools to be used by
organizations to assess environmental strengths and weaknesses, develop a strategic
plan and implement improved environmental practices, including resource conservation.
It offers a comprehensive step-by-step approach to help identify both economic and
environmental benefits through positive thinking, serious commitment and co-operative
action. Harmony Foundation of Canada also has climate-change-related publications.
Its publications can be ordered from the Web site at www.harmonyfdn.ca/pubs.html.
The National Round Table on the Environment and Economy (NRTEE) has a number
of programs that may be of interest to plastics processors. Information on programs and
publications includes the following:
•
Eco-Efficiency Indicators in Business.
•
Environment and Sustainable Development Indicators.
•
Sustainable Development Issues for the Next Decade.
NRTEE publications can be found at www.nrtee-trnee.ca.
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OTHER HELPFUL INFORMATION
9.5 POLLUTION PREVENTION GUIDANCE DOCUMENTS
105
Pollution Prevention Planning: Guidance Document and Workbook (Ontario Ministry of
the Environment, 1993. PIBS 2586E. ISBN 0-7778-1441-2). The workbook introduces
pollution prevention planning and implementation concepts and principles; offers a
model/approach to initiating team-planning exercises; and provides worksheets and checklists
for implementation. Available on-line at www.ene.gov.on.ca/envision/gp/2586e.pdf.
Canadian Standards Association has a wide range of published standards and guidelines for
pollution prevention and climate change mitigation. Its publications can be reviewed at
www.csa.ca.
9.6 ENVIRONMENTAL MANAGEMENT SYSTEMS
The Canadian Manufacturers and Exporters (CME), in conjunction with BRI
International Inc., has developed tools to help companies identify the gaps and implement
ISO 9001, 14001 and 18001 standards. These tools are accessible at the CME Web site at
www.cme-mec.ca/national/template_na.asp?p=44.
9.7 WEB SITES
Many manufacturers, government agencies, research organizations, utilities and industry
associations have Web sites. A relevant selection of some of these sites include the following:
•
Canadian Plastics Industry Association (www.cpia.ca)
•
Natural Resources Canada, Office of Energy Efficiency (oee.nrcan.gc.ca)
•
Environment Canada (www.ec.gc.ca/climate/home-e.html)
•
Centre for the Analysis and Dissemination of Demonstrated Energy Technologies
(www.caddet.org/index.php)
•
United States Environmental Protection Agency Web site has information on the
substitution of hydrofluorocarbon for hydrochlorofluorocarbons for the purpose of
reducing the emission of ozone-depleting substances
(www.epa.gov/docs/ozone/resource/business.html)
•
United States Department of Energy (www.energy.gov)
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9.8 ACRONYMS
106
ABS acrylonitrile butadiene styrene
AC alternating current
BDC brushless direct current
CPI formerly Canadian Plastics Institute, now Canadian Plastics Industry Association
CPIA Canadian Plastics Industry Association
CPRA Canadian Polystyrene Recycling Association
DC direct current
EPA Environmental Protection Agency
EPIC formerly Environment and Plastics Institute of Canada, now Environment Plastics
Industry Council
EPS expanded polystyrene
GPP general purpose polystyrene
HCFC hydrochlorofluorocarbon
HE high efficiency
HDPE high density polyethylene
HFC hydrofluorocarbon
HP horsepower
HVAC heating, ventilation and air conditioning
ICI industrial, commercial and institutional
JIT Just in Time
LDPE low density polyethylene
LLDPE linear low density polyethylene
MOE Ministry of the Environment
PC polycarbonate
PE polyethylene
PET polyethylene terephthalate
PP polypropylene
PS polystyrene
PVC polyvinyl chloride
3Rs reduce, reuse and recycle
RCO Recycling Council of Ontario
SPI Society of the Plastics Industry of Canada, now CPIA
VOC volatile organic compound
VSD variable speed drive
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9.9 GLOSSARY
107
Band heater
Electrical resistance heater that encircles the barrel of a screw to provide supplementary
heating and temperature control.
Barrel
Cylinder that houses the screw in an extrusion or moulding process.
Blender
A unit to mix and meter resins and/or additives in desired proportions.
Blow moulding
A process that uses compressed air to inflate a hollow tube of plastic inside a mould.
Blown-film extrusion
A process that uses air to inflate and cool a “bubble” of plastic into a thin film.
Typically used for manufacturing plastic bags.
Captive processor
A manufacturing operation that produces plastic products for internal use, rather than for sale.
Cartridge heater
A tubular heater often inserted into a mould to provide controlled heating.
Chiller
A unit designed to circulate a coolant (often water) to processing equipment.
Coextrusion
The process of extruding two or more different resins at the same time into
a single end product.
Contaminant
Foreign materials (such as dirt, metals, incompatible resins, organic waste, oil or the
residues of the contents of plastic containers) that make plastic materials more difficult
to process and cause quality problems in finished products.
Degradable plastics
Plastics specifically developed or formulated to break down after exposure to sunlight
or microbes.
Die
A metal plate through which molten material is forced. A precisely designed and cut profile in
the die forces the molten plastic to assume a desired shape and to begin the cooling process.
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Energy recovery
A process that extracts energy value from a substance such as air, water or solid waste and
transfers it to another medium to be used again. Examples are heat recovery from exhaust
streams to preheat incoming air or burning solid waste as fuel to generate heat.
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Extrudate
Material that has been forced through a die in an extrusion process.
Extrusion
The process of forcing molten plastic through a die to produce continuous lengths
of material with a desired profile.
Fillers
An inert substance added to plastic to reduce cost, or to improve physical properties.
Foaming agents
Chemicals added to plastics and rubbers that generate gases during processing and
produce a cellular structure.
Grinding
The process of reducing plastic components into smaller particles suitable for feeding into
a process.
Injection moulding
A plastics manufacturing process that injects molten material into a closed mould under
high pressure.
Injection blow moulding
A plastics manufacturing process that combines injection and blow moulding. An injection
moulded preform is transferred to a blow moulding station to be processed into the final
configuration.
Just in Time (JIT)
A manufacturing philosophy designed to reduce inventories and lead times by reducing
set-up times in the manufacturing process.
Monomers
The basic chemical building blocks used to create plastic polymers (long chain molecules).
Mould
A two-part unit into which material is introduced and which is configured to produce a
desired shape. The mould is often cooled to speed up the solidification of molten material.
After solidification, the mould is opened to remove the finished part.
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Multi-cavity
Refers to a mould with more than one cavity. For high volume production, moulds with
more than one hundred cavities are common.
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Off-spec resin
Any resin that does not meet its manufacturer’s specifications, but may still be offered for sale.
Ontario Regulation 347
Waste Management—General Regulation 347, under Ontario’s Environmental
Protection Act, sets out standards for solid waste disposal sites and waste management
systems, and governs the handling, transport and disposal of registerable liquid
industrial and hazardous wastes.
Parison
A round hollow tube of molten plastic that is extruded from the head of a blow-moulding
machine.
Payback
Payback (simple payback) is the ratio of the annualized saving from a process or machinery
improvement divided by the capital and installation cost of the improvement project.
Pellet
A small piece of plastic resin, suitable for feeding into a process.
Plastics
Synthetic materials consisting of large polymer molecules derived from petrochemicals or
renewable sources. Plastics are capable of being shaped or moulded under the influence of
heat, pressure or chemical catalysts. Polymer resins are often combined with other ingredients,
including colourants, fillers, reinforcing agents and plasticizers, to form plastic products.
Polymer
A very long chain molecule built up by repetition of small chemical units, known as
monomers, strongly bonded together.
Preform
An injection moulded intermediate product that is inserted into a blow-moulding machine.
Process
Aspects of a manufacturing operation, such as moulding or extrusion, that are directly
related to the physical transformation of the material.
Properties
The physical characteristics of materials that may be used to differentiate plastics among
themselves and other materials.
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Reinforced plastics
Plastic materials that have added reinforcing materials, such as glass fibres or mats.
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Resin
A synonym for “polymer.”
Screw
A shaft with flights, confined within a barrel, that conveys material from a hopper to a
die or a mould. The material is plasticized during this process through a combination of
mechanical “shear” heating and external heat provided by band heaters around the barrel.
Shot
A precise amount of molten plastic material introduced into a mould during the injection
moulding process.
Sheet moulding compound
A ready-to-mould fibreglass reinforced polyester material used for compression moulding.
Strip heater
A flat electric resistance heater.
Thermoplastics
Plastic resins that can be repeatedly softened by heating, shaped by flow into articles
by moulding or extrusion, and hardened.
Thermosets
Plastic resins that are hardened or “cured” by an irreversible chemical reaction that creates
strong cross-links between the polymer molecules. Once formed, thermosets cannot be
re-melted without degrading the resin.
Three Rs (3Rs)
The reduction, reuse and recycling of waste.
Virgin materials
Any raw material intended for industrial processing that has not been previously used.
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APPENDICES
APPENDIX II
ISO 14000 STANDARD SERIES
APPENDIX I: ISO 14000 STANDARD SERIES
112
Number
Standard Title
14001
EMS – Specification With Guidance for Use
14004
EMS – General Guidelines on Principles, Systems and Supporting Techniques
14010
EA – General Principles of Environmental Auditing
14011.1
EA – Audit Procedure Part 1: Auditing of EMS
14012
EA – Qualification Criteria for Environmental Auditors
14014
EA – Initial Reviews
14015
EA – Environmental Site Assessments
14020
EL – General Principles
14021
EL – Self-Declaration, Environmental Claims, Terms and Definitions
14022
EL – Self-Declaration, Environmental Claims, Symbols
14023
EL – Self-Declaration, Environmental Claims, Testing and
Verification Methodologies
14024
EL – Practitioner Programs: General Principles, Practices and Certification
Procedures of Multiple Criteria Programs
14025
Type III Environmental Labelling
14031
Environmental Performance Evaluation
14040
LCA – General Principles and Guidelines
14041
LCA – Inventory Analysis
14042
LCA – Impact Assessment
14043
LCA – Interpretation
14050
Terms and Definitions
14060
Guide for the Inclusion of Environmental Aspects in Product Standards
EMS – Environmental Management System
EA – Environmental Auditing
EL – Environmental Labels and Declarations
LCA – Life Cycle Assessment
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SCOPE OF GENERIC PLASTICS MANUFACTURING PROCESSES USED IN CANADA
APPENDIX II: SCOPE OF GENERIC PLASTICS MANUFACTURING
PROCESSES USED IN CANADA
Process
Major Resins Used
Film extrusion
PE, PP, PS, Nylon
Injection moulding
PE, PP, PVC, PS, ABS, PET, Nylon, Acrylic
Profile extrusion
PE, PVC, PS, ABS, Nylon
Sheet extrusion
PVC, PE, PS, ABS, PP, Acrylic
Foam extrusion
PS, PE, Phenolic
Calendered sheet extrusion
PVC, PS, PE, Acrylic, ABS
Plastisol processing
PVC
Rotational moulding
PE, PP
Blow moulding
PE, PP, PET, PVC
Lamination, film
PE, Nylon, PET
Lamination, thermoset
Phenolic, Urethane, Polyester
Compression moulding
Phenolic, U-F, M-F
Spray/pour
Urethanes
Open moulding
Urethanes, Phenolic, U-F
Filament winding
Polyester, Epoxy
Pultrusion
Polyester, Epoxy
Matched die moulding
Urethanes, Polyester, Phenolic
APPENDIX III
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Source: Law, Sigurdson and Associates, 1993.
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APPENDIX IV
SELECTED CASE STUDIES FROM IMPROVING ENERGY EFFICIENCY AT U.S. PLASTICS MANUFACTURING PLANTS
APPENDIX III: SELECTED CASE STUDIES FROM IMPROVING ENERGY
EFFICIENCY AT U.S. PLASTICS MANUFACTURING PLANTS
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The Society of the Plastics Industry Inc. and the U.S. Department of Energy published a
series of case studies in the publication Improving Energy Efficiency at U.S. Plastics
Manufacturing Plants (September 2005). Below is a summary of a selection of these case
studies. For more details, visit www.eere.energy.gov/industry/bestpractices/
iac_tools_and_publications.html.
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Case Study Title
Summary
Precise Technology, Inc.
Total savings of $105,000, reducing total energy use by
22 percent. Areas of improvement included lighting,
compressed-air system, HVAC and motors.
Spartech Plastics
Total savings of $113,000. Areas of improvement
included heat recovery, lighting and insulation.
Superfos Packaging
Total savings of $100,000, reducing total energy use
by approximately 13 percent. Areas of improvement
included machine insulation, motor management,
compressed-air system and lighting.
ENERGY EFFICIENCY OPPORTUNITIES
IN THE
CANADIAN PLASTICS PROCESSING INDUSTRY
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