Biodiesel Fuel Management Best Practices for Transit

Biodiesel Fuel Management Best Practices for Transit
Biodiesel Fuel Management
Best Practices for Transit
November 27, 2007
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November 27, 2007
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5. FUNDING NUMBERS
Biodiesel Fuel Management Best Practices for Transit
MO-26-7009-00
6. AUTHOR(S)
National Biodiesel Board – Primary Contractor
Advanced Fuel Solutions - Subcontractor
8. PERFORMING ORGANIZATION
REPORT NUMBER
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)
National Biodiesel Board
3337A Emerald Lane
P.O. Box 104898
Jefferson City, MO 65110
FTA-MO-26-7009.2007.1
Advance Fuel Solutions
PO Box 291
Lynnfield, MA 01940
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)
10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
Federal Transit Administration
U.S. Department of Transportation
Washington, DC 20590 Website URL [www.fta.dot.gov]
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Supplementary Notes.
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Available From: National Technical Information Service/NTIS, 5285 Port Royal
Road, Springfield, Virginia 22161. Phone 703.605.6000, Fax 703.605.6900,
Email [[email protected]]
13.
ABSTRACT (Maximum 200 words)
Public transportation systems play a key role throughout the country not only in providing vital services to citizens
but also in the environmental quality of our communities. Transit systems nationwide are seeking out new
technologies in order to increase US energy independence and reduce emissions by switching to biodiesel in
diesel buses.
This report discusses the benefits and challenges to the transit industry of using biodiesel. It provides
information on the characteristics of biodiesel and biodiesel blends and discusses best practices for the
procurement, blending, storage and use of biodiesel.
.
14. SUBJECT TERMS
15. NUMBER OF PAGES
Biodiesel, Transit, Public Transportation, Alternative Fuel, Biodiesel Properties
70
16. PRICE CODE
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ABSTRACT
Table of Contents
Notice/Disclaimer ........................................................................................................................... 1 Acknowledgments........................................................................................................................... 1 List of Figures ................................................................................................................................. 2 Abbreviations and Acronyms ......................................................................................................... 3 Executive Summary ........................................................................................................................ 4 Introduction ..................................................................................................................................... 5 General Fuel Management Practices .............................................................................................. 8 Common Contaminants Found in Diesel Fuel ............................................................................ 8 Fuel Economy ........................................................................................................................... 10 Primary Function of Diesel Detergents..................................................................................... 11 EMA Recommended Premium Fuel Properties ........................................................................ 11 Fuel Stability ............................................................................................................................. 11 Lubricity in Today’s Fuels ........................................................................................................ 12 Low Temperature Operability................................................................................................... 13 Biodiesel Basics ............................................................................................................................ 15 Advantages of Biodiesel ........................................................................................................... 15 Blend Name: (Bxx) vs. % Biodiesel ......................................................................................... 15 Color and Odor ......................................................................................................................... 18 Fuel ............................................................................................................................................... 18 Biodiesel ....................................................................................................................................... 18 Petrodiesel ..................................................................................................................................... 18 Biodiesel Energy Content ......................................................................................................... 18 Cold Flow Properties ................................................................................................................ 19 Cetane Number ......................................................................................................................... 19 Stability ..................................................................................................................................... 19 B100 Solvency .......................................................................................................................... 21 B100 Material Compatibility .................................................................................................... 21 Enhanced Lubricity ................................................................................................................... 22 Cold Weather Performance ....................................................................................................... 23 Biodiesel and Original Equipment Manufacturers (Warranties) .............................................. 24 Taxes and Incentives ................................................................................................................. 25 Environmental and Safety Information..................................................................................... 26 Housekeeping for Biodiesel and Middle Distillates ..................................................................... 27 Air ............................................................................................................................................. 27 Water ......................................................................................................................................... 27 Fuel Contaminants .................................................................................................................... 27 Storage Tank Challenges .......................................................................................................... 28 Maintaining Fuel Quality .......................................................................................................... 28 Key Points for Transporting Biodiesel ..................................................................................... 28 Key Points for Storage of Biodiesel.......................................................................................... 30 Blending B-100 ............................................................................................................................. 31 Preparing to Blend Biodiesel .................................................................................................... 31 Blending Strategies ................................................................................................................... 31 Cold Weather Blending............................................................................................................. 32 Infrastructure considerations ..................................................................................................... 34 Conclusion .................................................................................................................................... 42 Appendix 1: Material Safety Data Sheet ...................................................................................... 43 Appendix 2: EMA Consensus Position......................................................................................... 46 EMA Consensus Position: Joint EMA/TMC Pump Grade Specification for Premium Diesel
Fuel ........................................................................................................................................... 46 Significance and use of the recommended properties: ............................................................. 46 EMA Consensus Position ......................................................................................................... 50 Technical Statement on the Use of Biodiesel Fuel in Compression Ignition Engines ............. 51 Appendix 3: Biodiesel Quality Assurance Program for the Fleet................................................. 57 Fleet Fuel Purchasing Checklist................................................................................................ 58 Appendix 4: ASTM D 6751-07a................................................................................................... 60 Biodiesel (B100) ........................................................................................................................... 60 Appendix 5: ASTM D 396 ............................................................................................................ 61 Heating Oil .................................................................................................................................... 61 Appendix 6: Addressing Fuel Quality Deficiencies with Additives ............................................. 62 Summary of General Distillate Fuel Additives......................................................................... 66 Appendix 7: Diesel Fuel Properties – for #2 LSD/ULSD ............................................................ 69 D 975 – 06b vs. EMA FQP-1A ..................................................................................................... 69 U.S. Ultra Low Sulfur Diesel Fuel Properties .......................................................................... 70 Appendix 8: Information Resource Websites ............................................................................... 71 Appendix 9: Engine Manufacturers’ Biodiesel Statements .......................................................... 72 Notice/Disclaimer
This document is disseminated under the sponsorship of the Department of Transportation in the
interest of information exchange. The United States Government assumes no liability for its
contents or use thereof.
The United States Government does not endorse products or manufacturers. Trade or
manufacturers' names appear herein solely because they are considered essential to the object of
this report.
Acknowledgments
This document would not have been possible without the support of the Federal Transit
Administration, the National Biodiesel Board and the efforts of Advanced Fuel Solutions.
1
List of Figures
Figure 1: Biodiesel Blends by Percentage .................................................................................... 16
Figure 2: Lubricity of ULSD/Biodiesel Blends ............................................................................ 23
Figure 3: Air Flow Diagram ......................................................................................................... 27
Figure 4: Estimated Cost Comparisons of Biodiesel Infrastructure Options................................ 36
Figure 5: Ex. of Distillate Fuel Haze Rating Standard Using ASTM Clear and Bright Test ....... 58
List of Tables
Table 1: Requirements for Biodiesel Blend Stock as Listed in ASTM D6751-07a ..................... 17 Table 2: Key Fuel Specifications to Monitor ................................................................................ 18 Table 3: BTU Values .................................................................................................................... 18 Table 4: Cold Flow Properties ...................................................................................................... 19 Table 5: Summary of Hardness and Swell Characteristics ........................................................... 22 2
Abbreviations and Acronyms
ASTM
B100
B20
B5
BTU
CFPP
CI
CO
CO 2
DOE
ECRA
EPA
EPAct
GVWR
HC
MSDS
NBB
NORA
NO x
NPAH
NREL
OEM
PM
Ppm
SO 2
ULSD
VOC
BOL
COA
American Society for Testing and Materials
100% biodiesel
20% biodiesel, 80% petroleum diesel
5% biodiesel, 95% home heating oil
British thermal unit
Cold filter plugging point
Compression ignition
Carbon monoxide
Carbon dioxide
United States Department of Energy
Energy Conversation Reauthorization Act of 1998
United States Environmental Protection Agency
Energy Policy Act of 1992
Gross vehicle weight rating
Hydrocarbon
Material Safety Data Sheet
National Biodiesel Board
National Oil heat Research Alliance
Nitrogen Oxide
Nitrated polyaromatic hydrocarbons
National Renewable Energy Laboratory
Original Equipment Manufacturers
Particulate matter
Parts per million
Sulfur dioxide
Ultra low sulfur diesel
Volatile organic compound
Bill of lading
Certificate of Analysis
3
Executive Summary
The demand for energy security and environmentally friendly public policy has grown in recent
years. Consumers are seeking energy efficient products in all areas of American life from light
bulbs to biofuels. Demand for these products continues to grow, as consumers increasingly
recognize the impact our choices have on the environment. Security concerns arising from our
dependence on foreign oil has further increased interest in domestic alternatives. These
environmental and security factors have led to a period of extraordinary growth in the biodiesel
industry.
Public transportation systems play a key role throughout the country in providing vital services
to citizens and in the environmental quality of our communities. Transit systems nationwide are
seeking out new technologies to reduce emission and increase energy efficiency. Because of the
unique role of transit systems within our nationwide transportation system, their efforts provide a
tremendous opportunity to explore new technologies and to disseminate information about
improving air quality and reducing dependence on foreign oil. One option being tried by transit
agencies is switching to biodiesel to fuel their diesel buses. Biodiesel has been used in city bus
fleets in Cedar Rapids, Iowa; Cincinnati, Ohio; St. Louis, Missouri, and the list is growing.
This document seeks to explain the benefits and challenges of biodiesel. It provides those in the
petroleum industry supply chain and those they serve with information ranging from storage to
shipping of biodiesel fuels. It also discusses best practices that will help ensure the quality of the
biodiesel product.
Biodiesel can have significant environmental benefits. Neat biodiesel (100% biodiesel) reduces
carbon dioxide emissions by more than 75% over petroleum diesel. A blend of 20% biodiesel
reduces carbon dioxide emissions by 15%. 1
Use and handling of biodiesel is similar to petroleum diesel. It operates in conventional engines,
typically without engine modifications, and it does not require substantial changes to fueling
infrastructure. Biodiesel has similar properties to petroleum diesel and the two fuels can be, and
often are, blended.
While the properties of biodiesel are similar to petroleum diesel, it is important to be aware of
differences, and to use good management practices to ensure successful handling and operation
when using biodiesel or blends. This handbook discusses the differences and explains how they
should be managed. With the use of good management practices, biodiesel and biodiesel blends
can contribute to our energy security, while reducing our impact on the environment.
1
“Biodiesel Benefits.” www.eere.energy.gov: Alternative Fuels Data Center.
4
Introduction
Crude oil, natural gas, refined products and petrochemicals are all sold in commodity markets.
Commodities are mass-produced, unspecialized products that are highly fungible, having
characteristics so similar that they are interchangeable. The “commodity” label often makes
differentiating one product from another challenging. Differentiating between products is critical
as the fuels industry moves towards alternative and enhanced products. As this shift occurs, both
consumers and the petroleum industry will realize key differences and benefits.
Biodiesel is gaining popularity in America. It is a clean-burning, alternative fuel derived from
domestic, renewable resources such as fats and oils. Biodiesel is made through a process called
transesterfication. The process of converting vegetable oils or animal fats into biodiesel is a
chemical reaction that uses an alcohol, such as methanol, and a catalyst, such as sodium
hydroxide.
Biodiesel can be used as a replacement or supplement for petroleum-based heating oil and diesel
fuel. Biodiesel does not require any special handling or storage facilities because it can be splash
blended with heating oil and diesel fuel in any concentration. However, splash blending should
eventually be transitioned to a more reliable electronically managed blending methodology to
ensure optimum blending. (This will be addressed later in this manual.) The use of biodiesel,
even at higher blends, does not necessarily require any major modifications to conventional
vehicle or home heating oil systems. (Minor modifications might be required to ensure material
compatibility.)
In its neat form, biodiesel offers significant environmental benefits. Biodiesel contains virtually
no sulfur. Furthermore, according to a U.S. Environmental Protection Agency (EPA) report
issued in October 2002, burning neat biodiesel (B100) reduces the emissions of particulate
matter and carbon monoxide by almost 50% and unburned hydrocarbons by almost 70%.
However, there is a slight increase in the nitrogen oxides (NOx) emissions, but blending reduces
NOx emissions to a negligible amount. Research indicates that NOx emissions for B20 blends
and lower in diesel engines may be the same or lower than that of petrodiesel alone, depending
on the testing protocol and application. Further work is ongoing in this area. In open flame
applications, where NOx results are more dependent upon fuel oxygen level rather than incylinder temperatures, B20 shows significant NOx reductions on the order of 10 to 20%
according to testing done at Brookhaven National Laboratory while maintaining the reductions in
other emissions normally observed in diesel engines.
Biodiesel has fully completed health effects testing requirements of the 1990 Federal Clean Air
Act Amendments. Any product marketed as biodiesel must meet the high standard set by the
ASTM.
Beyond environmental benefits, biodiesel is vital to maintaining America’s national security and
reducing this country’s dependence on imported oil. The United States accounts for
5
approximately 24% 2 of world-wide petroleum consumed, according to the US Department of
Energy. Continued dependence (58% in 2006 according to EIA) on imported oil in a volatile
geopolitical environment has the potential to create an economic and security crisis. More
efficient utilization of domestic surpluses of vegetable oils and waste fats, as well as the
development of specialized crops, could reduce U.S. dependence on imported oil and increase
national security.
Cost and availability has been most frequently cited as a barrier to widespread use of biodiesel.
Biodiesel initially was not meant to compete with generic petroleum products such as diesel fuel
and heating oil. It enabled petroleum companies to maintain market share with EPACT (Energy
Policy Act of 1992) fleets that were transitioning to alternative fuels, such as compressed natural
gas, to comply with government regulation. Biodiesel has made headway in new markets as an
alternative and/or supplement to diesel and heating oil applications. This has caused the
economics of these products to be weighed against one another. The biodiesel blenders’ tax
credit is also a key market driver since it provides biodiesel and petroleum handlers access to a
credit for each gallon of biodiesel blended with on- and off-road diesel fuel as well as heating oil.
Download the most recent copy of the U.S. Internal Revenue Service guidance document, which
describes the program in detail at http://www.irs.gov/pub/irs-pdf/p510.pdf.
The IRS has published updated versions of Form 637 and Form 720. These forms are available
by going to the Forms and Publications page of the IRS website, www.irs.gov. A direct link to
that page is http://www.irs.gov/formspubs/lists/0,,id=97817,00.html.
Form 637 is the registration application that all biodiesel producers and blenders must complete.
(Note: Becoming officially registered may take a considerable amount of time. Planning
accordingly to meet the deadlines prescribed by the IRS is critical. For information about the
registration process and timing, contact your local IRS field office.)
Form 720 is the Quarterly Federal Excise Tax Return. Entities utilize this form to report and pay
federal excise tax.
The biodiesel industry could see significant growth over the next few years. Several factors such
as the emergence of ultra low sulfur diesel (ULSD) regulations, the biodiesel mixture credit
program and potential integration into the heating oil pool will be drivers to increased use of
biodiesel. Technology will play a major role in lowering the cost of biodiesel production and
finding alternative higher value uses for the primary byproduct, which is glycerin.
This guide has been developed for the petroleum industry supply chain and those that they serve,
such as the transit industry. It will provide a broad range of information relating to liquid fuel
storage, blending and shipping and field use of diesel fuel, biodiesel fuel and blends of both.
Suggested quality practices will be discussed that will ensure a positive working experience for
fleet managers nationwide. Because biodiesel will primarily be a blend stock for diesel fuel and
heating oil we have included an equal amount of data on generic fuels and fuel additives. It is
2
July 2007 Monthly Energy Review. Energy Information Administration.
http://www.eia.doe.gov. August 2007
6
imperative that sound housekeeping practices be incorporated and adhered to throughout the
supply chain in order to achieve positive results with both middle distillates and biodiesel fuels.
7
General Fuel Management Practices
Fuel quality characteristics in the United States have undergone a number of changes that
severely impact fuel suppliers’ operations and profitability as well the fleet user’s operational
experience with the fuel. The most recent change impacting fuel quality has been the
introduction of ultra low sulfur diesel fuel. Technology demands and processing changes have
seriously impacted the use and storage of No. 1 and No. 2 fuels. Guidelines that have been in
place for 50 years require fuels to pass a limited number of tests which are designed to measure
fuel performance under controlled conditions with very tolerant engine and storage systems.
The limited number of tests that make up the specifications do not cover many physical
properties severely impacting storage and operations today. This is evidenced by the Engine
Manufacturers Association (EMA) pump grade specification. Emissions regulations are rapidly
changing and will continue to drive changes in diesel fuel composition and specifications.
Changes will include restrictions on certain fuel components, such as sulfurs and aromatics,
which have an unfavorable effect on exhaust emissions. However, they do not currently address
the negative impact on certain fuel characteristics, nor do they address the consequences that
poor fuel quality and contaminants will have on new, sophisticated engine technologies.
This chapter includes a brief summary of contaminants and fuel components, which could
potentially be present in your fuel. Additionally, an assessment of the causes and effects of poor
fuel performance has also been included for your review.
Common Contaminants Found in Diesel Fuel
ƒ
ƒ
ƒ
ƒ
ƒ
Water
Particulates (gums, dirt, fuel degradation material, sludge)
Surfactants
Microorganisms
Peroxides
Entrained Water
One of the most favorable characteristics of middle distillates is its natural ability to shed water,
thus preventing fuel/water emulsions. However, many diesel fuels
have recently shown a disastrous tendency to absorb and hold
large quantities of water. These fuel/water emulsions greatly
reduce the effectiveness of fuel/water separators and can rapidly
plug fuel filters. Typical causes of excessive entrained water
levels include microbial activity, surfactants, alcohols,
particulates, and poorly designed additives.
Free Water
Poor housekeeping is probably the largest contributor to the free water problem. Water enters
bulk fuel tanks via condensation, carry-over from the fuel distribution system, and leakage
through the fill cap, spill containment valve or piping. When water bottoms are allowed to build
8
up, significant quantities of water may be pumped into vehicle fuel tanks causing deleterious
operational effects.
Moisture promotes microbial activity, fuel/water emulsions, rust, and corrosion. The more water
is dispersed in fuel or in the fuel system, the greater the tendency for ice crystals to form and
grow when the fuel temperature falls below the freezing point of water. Even in warm weather,
water could lead to poor combustion. Even worse, it could contribute to injector failure.
Particulates
The most commonly recognized particulate contaminants found in diesel fuel are rust, dirt and
sludge. However, both diesel and biodiesel fuels can form their own solid particulate
contamination as they undergo complex chemical changes known as oxidation and
polymerization. In addition to oxidation, certain microbes grow in fuel and the microbes’ waste
products contribute to the overall particulate contamination.
Particulates become trapped in filter surfaces, tank walls, and fuel lines. The result is shortened
fuel filter life, dirty fuel tanks, clogged lines and plugged screens. Recently, many fleets have
seen fuel filters plugged with “black goop,” which can be caused by the particulates that are
filtered out of the fuel as they oxidize. The fuel filter may not trap finer particulates, which will
cause fuel system wear. This might include injector spray hole erosion; plunger damage and
premature fuel pump wear. Issues such as nozzle, filter and strainer plugging can result in
unscheduled service call for home heating systems.
Surfactants
Surfactants are substances that reduce the surface tensions of fuel/water
and thereby promote fuel/water emulsions. These surface-active
compounds come from various sources, including refinery treatment
chemicals, naturally occurring materials not removed from the crude oil,
pickup from other products in the distribution system, poorly formulated
additives, lube oil blended into the fuel, and even microorganisms.
Fleet operators need to pay attention to surfactants because they are
instrumental in causing slow water settling in fuel storage tanks. Operators should work to
prevent the coalescing of water by fuel/water separators. Surfactants will also disperse
microorganisms, rust, dirt and water throughout the fuel system. Certain types of surfactants
actually cause fuel filter restriction by giving the fuel an electrical charge.
Microbial Contamination
The most common means by which microbes enter the fuel system is through air drawn into the
tank as fuel is dispensed or used. Other sources of contamination may include ground water
encroachment, portable fuel transfer piping or hoses, or through the fuel delivery process.
Bacteria and fungi form biomass as they reproduce, which may accumulate at any place in the
fuel system where microscopic droplets of water exist. Common points of accumulation are the
fuel/water interfaces, tank surfaces and filters. Metabolic waste and dead cells accumulate and
9
they settle out as sludge. Particulates will be drawn out with diesel fuel if sufficient sludge builds
up. That can cause the filters and orifices to clog. Filter and line plugging results more often
from biofilm formation on transfer line walls and filter surfaces.
Reduced filter life often goes unrecognized in many operations where chronic microbial
contamination goes undetected. The problem’s existence is often only recognized after biomass
is inhibited and the consequent longer filter life is achieved. Occasionally catastrophic failures,
such as engine shut down due to fuel starvation, provide convincing evidence of the importance
of microbial contamination control.
One of the more sinister aspects of the filter-plugging problem is that often the biofilm is nearly
transparent and goes unnoticed. Microbial induced corrosion can severely damage main storage
tanks, vehicle tanks and fuel lines. This is usually noticed when catastrophic failures occur.
Engine wear is another effect of flow restriction. Non-uniform flow causes variation in
combustion within cylinders, increased piston wear rates and increased torque on camshafts all
translating to higher maintenance costs. ULSD will have most of the natural microbial inhibitors
removed by the hydro processing needed to get to 15 ppm sulfur. This will allow microbes to
thrive at an accelerated rate compared to today’s fuels. Biodiesel, like ULSD, also is virtually
sulfur free which makes it an equal candidate for microbial contamination if systems are not
regularly maintained.
Poor housekeeping starts the microbial process. Petroleum handlers need to implement a
thoughtful storage tank management program to reduce exposure to this challenging fuel quality
issue.
Peroxides
The refining process used to produce low sulfur fuel can lead to unexpected consequences. The
increased tendency for some severely hydro treated fuels to form high peroxide levels is an area
of significant concern. These levels can be high enough as to be incompatible to fuel system
components. Peroxide formation in severely hydro treated aviation fuel has been recognized for
some years. There have been field experiences of fuel system elastomers hardening and cracking
from exposure to high peroxide levels in aviation fuel. This has led to the specification for
limiting peroxides in some military fuels and requirements for the addition of anti-oxidants if the
fuel contains hydro treated components.
Initial research compiled by Advanced Fuel Solutions found that a large number of low sulfur
diesel fuels may have had a tendency to form high levels of peroxides which would necessitate
attention. In fact, it was suggested that high peroxide levels could damage fuel system
components. Ongoing evaluation by a national chemical manufacturer validated it is not
UNLESS the fuel is stored for a longer than normal period of time (>6 weeks).
Fuel Economy
Diesel fuel is one of the top three expenses for a fleet, and today’s fleet
managers are under greater financial pressure then ever before to reduce
fuel costs. Fuel economy becomes more important as the price of fuel
10
goes up. Crude oil was trading between $70 - $75 per barrel when this report was written, a
significant milestone in energy prices which is why fleets are using detergent packages to arrest
operational degradation caused by poorly performing fuel injectors. This strategy may help
maintain fuel economy through optimization of combustion.
Engine deposits are formed in the combustion chamber as a by-product of combustion. Small
amounts of deposits can degrade the spray pattern, which is vital for maximum combustion
efficiency. Diesel detergents, at the correct treat rate, can help remove existing deposits and
prevent new deposits from forming. The net benefits are in the return of lost fuel economy and
power, and lower emissions.
Primary Function of Diesel Detergents
According to Cummins, preventing formation of, and removing existing, deposits (coking)
caused by fuel recombination/decomposition results in optimal fuel spray pattern being
maintained (as demonstrated in the Cummins L-10 IDT and numerous other engine depositing
tests.) Other tests are being evaluated, but the measure of heavy duty performance remains the L10.
Benefits of detergent packages include:
•
•
•
•
•
•
•
•
Better fuel economy.
Better bottom line.
Reduced wear in the upper cylinder.
Reduction/prevention of ring deposits.
Restoration of horse power/torque.
Reduction of combustion noise.
Reduction of emissions and black smoke.
Reduced maintenance of injector system and
extended vehicle life.
EMA Recommended Premium Fuel Properties
Joint EMA/TMC Pump Grade Specification for Premium Diesel Fuel specification
The Engine Manufacturers Association has made very clear statements on the type of fuel quality
they desire for optimum performance. Additives can help to economically achieve those
specifications. The complete text and additional information on this specification can be found at
www.enginemanufacturers.org. Please see Appendix 2 for EMA Consensus Position.
Fuel Stability
Today’s commercially available fuel can deteriorate through oxidation and complex chemical
changes between hydrocarbons and various organic compounds naturally present in fuel.
Fuel composition, environmental factors and time directly influence the rate at which these
processes proceed. Diesel fuel is increasingly being used as a coolant for high-pressure fuel
injection systems, which can thermally stress the fuel. Thermal stress is often responsible for fuel
11
degradation and the formation of sediments, which can cause fuel flow to be restricted through
filters and injection systems.
The sediments are products of the complex chemical changes between oxygen, hydrocarbons and
other organic compounds. These products can cause fuel system damage and performance
deterioration in the field. This might include, for example, deposit formation on the injectors and
in the combustion chamber and filter plugging. Accelerated Stability (ASTM D6468, Octel F21)
is a test method that determines the relative instability of a fuel subjected to a thermal
degradation process. The significance of the test lies in the fact that a similar environment is
created as the fuel used to cool the injectors returns “hot” to the fuel tank. This test is currently
one of the test methods specified by the NCWM for defining a “Premium Diesel Fuel.”
In the test, the fuel is passed through a filter pad to trap any solid material that might already be
present in the fuel prior to heating. The fuel is then subjected to a heating process that accelerates
chemical reactions naturally occurring in unstable fuels. The newly created fuel degradation byproducts, in the form of insoluble gums and solid particulate matter, are then trapped as the fuel
is passed through another clean filter pad.
The pads are evaluated using a photometer’s
percent reflectance. The lower the percent
reflectance, the heavier and larger the deposits. For
proper performance, a fuel should not have a
percent reflectance less than 80% after aging for
three hours at a temperature of 302° F (150° C). In biodiesel, fuel aging and oxidation can lead to
high acid numbers, high viscosity, and the formation of gums and sediments that clog filters.
Lubricity in Today’s Fuels
Lubricity is described by the ability of a fluid to minimize friction
between – and minimize damage to – surfaces in relative motion under
loaded conditions. Diesel fuel injection equipment relies on the
lubricating properties of diesel fuel. Shortened life of engine
components such as fuel injection pumps and unit injectors can
usually be attributed to very low fuel lubricity.
Today’s on road diesel fuel encounters increasingly deeper
hydrodesulfurization in order to meet lower sulfur targets. The hydro
treating and hydro cracking processes remove naturally occurring
polar fuel components that afforded relatively effective protection.
The transition to ULSD fuel in 2006 made these problems worse as it relates to lubricity.
Resolving lubricity deficiencies can be achieved by using, a 1% to 2% blend of biodiesel or
using one of the widely available commercial lubricity additives.
A lubricity improver or low blends of biodiesel will restore the boundary lubrication between
metallic parts in critical fuel system components by forming a protective layer on the metal
surfaces. Lubricity is currently measured in the lab with a High Frequency Reciprocating Rig
12
(HFRR). HFRR became the ASTM standard to measure fuel lubricity in all fuels once the
January 1, 2005 specification took effect. The fuel must meet a wear scar of 520 mm.
Low Temperature Operability
Cold weather continues to present challenges for diesel operability. Part of the solution to
achieve winter operability has been a diesel user’s reliance
on a combination of kerosene blending and commercially
available fuel additives. Before the transition to ULSD the
rule of thumb had been that for every 10% of kerosene
blended with generic diesel fuel a gain of 1° F to 3° F drop
in the operability value would be achieved. Today ULSK
does not perform as well to help improve the winter
operability of diesel fuels. ULSK like ULSD undergoes the
same refining processing to reduce the sulfur to <15 ppm
levels making both diesel and kerosene a challenge to optimize for winter operability conditions
while continuing to suffer from historical supply and economic volatility, fuel economy penalties
and challenged lubricity levels.
Kerosene blending has additional operational concerns making it less desirable than other
commercially available options. Increased cost differentials between diesel and kerosene pricing
as well unpredictable availability makes kerosene a volatile cold flow reduction strategy during
winter months. Decreases in fuel economy noted with kerosene blending are also a noted
downside to winter blending that fleets have dealt with for decades, which is the opposite of the
benefits of using a proven commercially available winter fuel cold flow additive to achieve cold
weather operational goals.
Cold flow additives have proven to be more cost effective in optimizing winter performance
when compared to blending with kerosene and likely will not be subjected to the volatile pricing
and supply concerns associated with kerosene. Seasonal winter diesel additives properly
administered at the wholesale fuel rack level contain advanced chemical wax modifiers and deicing compounds designed to provide reliable winter operability without compromising fuel
economy. Many fleets that attempt to use additives in the downstream, however, are challenged
to administer them in a cost effective manner due to the lack of automated injection systems.
These type of additives need to be proportionally blended and added to the fuel before the fuel
meets it's posted cloud point or they will be unreliable.
Nucleation technology, advanced copolymers, and wax anti-settling additives are only a few of
the solutions you may choose from to address cold flow challenges. Additionally, cold flow
chemistry can be adjusted through injection system optimization to gain enhanced winter
performance in your specified region of the nation. The latest in technology combined with
laboratory services is the trouble-free way to assure:
ƒ
ƒ
ƒ
Reliable operation of equipment.
Proper engine power and fuel efficiency.
Lower fuel costs.
13
ULSD fuel has proved to be a challenge at the fleet level due to its increased levels of wax
concentration as well as the speed with which the wax precipitates from the diesel fuel. This has
created a greater demand for new cold flow improver technologies, which national chemical
manufacturers continue to improve upon, in this second year of ULSD availability. It is
imperative that fleet managers get the most reliable data on the cold flow properties of their
generic diesel fuel before beginning to blend their biodiesel stock.
It is highly recommended to challenge your present and future additive counselors on the
performance of the chemistry which they offer. The best recommendation one could make to an
interested fleet manager seeking guidance on optimizing the fleet to perform in cold weather is to
secure a few quarts of generic fuel or if biodiesel blends are to be used, a finished sample of the
appropriate blend. Ask your additive representative to submit both a small sample of the
proposed formula following the recommendations and run several of the following tests to see
for yourself what the performance of these elixirs are before submitting your equipment to a field
test.
Suggested Low Temperature Operability Tests
These tests were developed to help determine when a fuel would no
longer be operationally acceptable for certain applications. The
main concern for diesel users is the Cold Filter Plugging Point test
and Low Temperature Flow Test. Both tests can help determine the
lowest temperature at which a diesel vehicle could operate.
Cold Filter Plugging Point ºC (CFPP) D6371, I.P. 309)
This ASTM test method is used to predict the low temperature
operability limits of a fuel. The test is used to determine the temperature at which wax crystals
precipitate out of a diesel fuel and plug equipment filters. This information is used to determine
the temperatures (above the CFPP) at which a fuel is expected to give trouble free flow within a
fuel system.
Low Temperature Flow Test (ASTM D4539)
The Filterability of Diesel Fuels by Low-Temperature Flow Test (LTFT) estimates the
filterability of diesel fuels in some automotive equipment at low temperatures. At temperatures
below the LTFT, operability problems may begin to develop.
14
Biodiesel Basics
Biodiesel is an alternative fuel product that is manufactured from vegetable oils, recycled
cooking greases, or animal fats. This alternative fuel product is created through a unique
manufacturing process, which converts the oils and fats to long chain mono alkyl esters. The
resulting product, B100, must adhere to the requirements of latest revision of ASTM D6751,
which at time of this publication’s release is ASTM D 6751-07a.
Biodiesel is legally registered as a fuel and fuel additive with the United States Environmental
Protection Agency (EPA) and is a legal fuel for commerce. The EPA registration is not
dependent on the feedstock and includes biodiesel made from most animal fats, vegetable oils,
and greases. Raw or refined vegetable oil, or recycled grasses that have not undergone the
conversion to biodiesel ARE NOT BIODIESEL, and should not be used as such. Biodiesel is the
only alternative fuel that has complied with a four-year, $2.2 million health effects testing
regimen required by Section 211(b) of the 1990 Clean Air Act Amendments.
Biodiesel is a very versatile fuel that can be used as a substitute or additive for many petroleumbased products. Biodiesel and/or biodiesel blends have been proven effective as lubricity
additives and for use in home heating systems, automotive engines, and other equipment
designed to use diesel fuel. Biodiesel has many advantages as an alternative fuel:
Advantages of Biodiesel
•
•
•
•
•
•
•
•
•
Renewable
Energy efficient
Positive environmental characteristics: nontoxic, biodegradable, suitable for
environmentally sensitive areas
Interchangeable in most diesel equipment (minor adjustments may be necessary)
Global warming emission reductions (CO 2 , SO 2 , CO, HC, and soot)
Domestically produced from agricultural or recycled resources
Easy handling
Variety of applications (blend stock for diesel fuel, heating oil, etc.)
Easy to transition in and out without presenting disruption to your operations.
Blend Name: (Bxx) vs. % Biodiesel
Biodiesel can be used in its pure form (B100) or as a blend (Bxx) with traditional petroleum
products. The blend is identified using B followed by the percentage of biodiesel in the finished
product. Common blends include B2, a 2% biodiesel blend, which is often used for added
lubricity; and B20, a 20% biodiesel blend, which is the minimum blend level that can be used by
fleets covered by the Energy Policy Act of 1992. B20 is popular because of its balance of cost,
cold weather performance, materials compatibility, and solvency issues.
The National Oil heat Research Alliance (NORA) has embraced a 2% to 5% blend of biodiesel
over the next three years into conventional home heating oil following four-and-a-half years of
technical review. Testing has been done on blends up to 20% with positive environmental and
operational results. The industry is more receptive to lower blends due to fuel economics, supply
15
capabilities and neat biodiesel solvency at least until more technical data can be amassed to
address these issues.
Figure 1: Biodiesel Blends by Percentage
Blend Percentage
100
80
60
Diesel
40
Biodiesel
20
0
B2
B5
B20
B100
Pure Biodiesel (B100) can be used as a blending agent or as a pure fuel in diesel applications.
B100 has the following key physical properties:
•
•
•
•
•
•
•
It contains less than 15 ppm sulfur.
It contains no aromatics.
It has a high cetane level (47+).
It is biodegradable.
It is non-toxic.
It has a high flashpoint (higher than 260° F).
It has a comparable BTU value (8% less than No. 2 diesel).
B100 used as either a blending agent or as a pure fuel must meet the requirements as listed by
ASTM D6751-07a.
16
Table 1: Requirements for Biodiesel Blend Stock as Listed in ASTM D6751-07a
Property
ASTM Method
Limits
Units
Flash Point
D93
130.0 min.
Degrees C
Water and Sediment
D2709
0.050 max
% vol.
KinematicViscosity,40C
D445
1.9 - 6.0
Sulfated Ash
D874
0.020 max.
% mass
Sulfur (S 15 grade)
D5453
0.0015 max.
ppm
Sulfur (S 500 grade)
D5453
0.05 max.
ppm
Copper Strip Corrosion
D130
No. 3 max.
ppm
Cetane
D613
47 min.
Cloud Point
D2500
Report Customer
*Carbon Residue
D4530*
0.050 max.
% mass
Acid Number
D664
0.50 max.
mg KOH/gm
Free Glycerin
D6584
0.020 max.
% mass
Total Glycerin
D6584
0.240 max.
% mass
Phosphorus Content
D4951
10 max
ppm
Distillation Temperature,
Atmospheric Equivalent
Temperature,
90% Recovered
D1160
360 max
Degrees C
Combined Na/K
EN 14538
5 ppm
Combined Ca/Mg
EN 14538
5 ppm
ppm
Oxidation Stability
EN 14112
3 min
hours
*Workmanship
See below
mm2/sec.
Degrees C
ppm
*Carbon residue, 100% of sample
*Workmanship, free of un-dissolved water, sediment & suspended matter
Bold criteria = BQ-9000 “Critical Specification Testing once production process under control.
Note: A considerable amount of experience with a B20 blend exists in the United States.
Although B100 can be used, blends higher than B20 should be evaluated on a case-by-case basis
until further knowledge is available. Modifications of individual limiting requirements may be
agreed upon between purchaser, seller and manufacturer to meet special operating conditions.
The above tests are based on the most recent revisions of ASTM D6751, D6751-07a at time of
publishing this document, which ensures the quality of the biodiesel (B100) and its blends.
Currently, the ASTM has no defined standards for the various biodiesel blends. However, it is
expect that ASTM will have these standards in place in the near future. Please reference the
ASTM website atwww.astm.org for updates to these standards.
17
Color and Odor
Biodiesel will not have one specific color or odor. Both these properties depend on a number of
factors including the feedstock and manufacturing process. Therefore, biodiesel can meet ASTM
D6751-07a and have a variety of odors and colors. Initiate a testing process if you are concerned
that the fuel may not smell or look right. However, if there is a concern over color or odor, refer
to Table 2 for industry specifications to monitor.
Table 2: Key Fuel Specifications to Monitor
Fuel
Standard
Biodiesel
ASTM D 6751-07a
Petrodiesel
ASTM D 975
Specifications to Monitor
Flash Point
Cetane number/index
Acid Number
Cloud Point
Free glycerin
Pour Point
Total glycerin
CFPP
Water and Sediment
Water & Sediment
Cloud Point
Sulfur
Sodium & Potassium
Lubricity
Oxidation Stability
Biodiesel Energy Content
Biodiesel contains the highest British Thermal Unit (BTU) content of any alternative fuel.
Biodiesel contains 8% less energy per gallon than No. 2 diesel and 12.5% less energy per pound.
Unlike with diesel fuel, the composition, blending, and refining methods have no significant
impact on the energy content of B100. Biodiesel made from most of the common feedstock will
have the same impact on fuel economy power and torque. The difference in power, torque and
fuel economy can be noticeable when using B100. As the proportion of biodiesel within the fuel
blend is decreased (B20) these differences become less apparent. Specific BTU values can be
found in Table 3.
Fuel
#2 Diesel
Biodiesel (B100)
Table 3: BTU Values
Btu/lb
Btu/gal
18,300
129,050
16,000
118,170
18
Cold Flow Properties
Table 4: Cold Flow Properties
B100 Fuel
3
Soy Methyl Ester
Canola Methyl Ester
Lard Methyl Ester
Edible Tallow Methyl Ester
Inedible Tallow Methyl Ester
Yellow Grease 1 Methyl Ester
Yellow Grease 2 Methyl Ester
Cloud Point
Pour Point
F
36
27
57
68
73
108
46
F
30
25
52
55
46
54
46
C
2
-3
14
20
23
42
8
C
-1
-4
11
13
8
12
8
Cold Filter Plug Point
F
28
25
52
57
50
52
34
C
-2
-4
11
14
10
11
1
B100 should be stored at temperatures at least 15° F higher than the cloud point. Generally,
storage temperatures of 45° F to 50° F are acceptable for most B100. However, some B100 fuels
may require higher storage temperatures. These temperature requirements make most
underground storage facilities adequate, but aboveground fuel systems should be protected with
insulation, agitation, heating systems or other methods depending on the climate. These
precautions should also be taken with piping, tanks, pumping equipment, vehicles or any other
equipment, vehicles or any other equipment used for the transport or storage of the fuel.
Commercially available cold flow additives have had negligible effect on biodiesel produced in
the United States. The effectiveness of the additives varies greatly depending on the type of
biodiesel and the processing that it has undergone. The cold flow additives currently in
commercial use have been used much more successfully with biodiesel blends. For further
information review the additive section of this manual or contact your incumbent additive
counselor for guidance on additive applicability for your specific blend.
Cetane Number
All B100 fuels meeting the ASTM D6751-07a standard must have a cetane number above 47.
Therefore, biodiesel has a higher cetane number than most U.S. diesel fuel, which will provide
easier starting, quieter operation, and a more complete burn resulting in lower emissions.
Stability 4
Degradation of biodiesel follows two main chemical processes; hydrolysis and oxidation.
Hydrolytic instability is a result of exposure of the biodiesel to water, which may increase the
acidity of the biofuel which directly increases the rate of degradation of the biodiesel. The
second driver of instability is oxidative instability which is a result of both the biodiesel and
petroleum diesel being exposed to atmospheric oxygen which results in formation of peroxides.
3
Handling and Use Document, 2nd Addition, Department of Energy/DOE/GO-1020062288, March 2006, page 18.
4
Biodiesel Market Concerns and Solutions, PLMR 2007-01 Issue 2, 4/2007, Innospec
Fuel Specialties, Littleton, CO.
19
These peroxides undergo subsequent transformation to produce alcohols, aldehydes, ketones, and
carboxylic acids. This transformation then becomes the catalyst to form gums and polymers
which can be detrimental to engine components. The final driver in fuel instability is thermal
instability; generally biofuels in the absence of oxygen and water are thermally stable. However
prolonged storage at elevated temperatures can cause an increase in rates of other degradation
processes (Microbial, Hydrolytic, and Oxidative) and results in enhanced instability.
Short-term storage (one to four months) of B100 has been very successful with little or no
stability problems. The ASTM D4625 data suggests that biodiesel can be stored safely for eight
months to a year depending on the type of fuel and the stability of that fuel.. Any fuel stored for
more than six months may warrant the use of antioxidants and should be tested periodically for
acid number, viscosity and sediments.
Today specific stabilizing additives are widely available that will address biodiesel instability. It
is recommended that you contact your additive counselor for application recommendations.
Tips on Ensuring Biodiesel Stability
•
•
•
•
•
•
•
5
Know the level of saturation of your biodiesel. The lower the level of saturation the
more likely the fuel will oxidize. Saturated fatty acids are stable, and each time the level
of saturation decreases the stability of the fuel goes down by a factor of ten.
Do not store B100 in clear totes in the summer. Heat and sunlight will accelerate the
oxidation process.
Do not store B100 for long periods of time in systems containing reactive materials.
Certain metals such as copper, brass, bronze, lead, tin, and zinc will serve to accelerate
the degradation process and form even higher levels of sediment than would be formed
otherwise. Metal chelating additives may reduce the negative impact of the presence of
these metals.
Know how your fuel is processed. Bleaching, deodorizing or distilling oils and fats
before or as a part of the biodiesel process can remove natural antioxidants, which will
lessen fuel stability.
Keep oxygen away from fuel. By limiting the fuel’s exposure to oxygen the risk of fuel
oxidation can be greatly reduced or eliminated. This will increase the storage life of the
biodiesel.
Antioxidants protect stability. Antioxidants, whether natural or incorporated as an
additive can significantly increase the stability of biodiesel.
B100 Microbial Contamination. Biocides are recommended for conventional and
biodiesel fuels wherever biological growth in the fuel has been a problem. If biological
contamination is a problem water and sediment contamination must be controlled.
5
Tyson, Shaine. 2004 Biodiesel Handling and Use Guidelines. Department of
Energy/NREL. DOE/GO 102004. September 2004: Page 21-23.
20
In some cases, the cleaning effect or solvency of B100 has been confused with gums and
sediments that could form over time in storage as fuel ages. Tests of the acid number and the
viscosity should be performed to determine the cause of the sediment. If these numbers are
within ASTM specifications the sediment is most likely the result of the solvency of B100. 6
B100 Solvency
Biodiesel is comprised of methyl esters. Methyl esters are mild solvents and have been used as
low volatile organic compound cleaners for years. Thus, B100 may dissolve the accumulated
sediments in diesel storage and engine fuel tanks. Dissolved sediments can plug fuel filters and
cause fuel injector failure. Therefore, if biodiesel will be used or stored, the following
considerations should be made: 7
1. Carefully clean the tanks and fuel system where any sediments or deposits may exist.
Petroleum handlers should be evaluating bulk storage tanks regardless of possible
biodiesel storage and distribution to ensure fuel quality preservation of conventional
distillates is maintained.
2. Be prepared for the possibility of some filter clogging and more frequent filter changes
until the system has been cleaned of old sediments. Once the system is cleaned the filter
change interval should return to normal intervals.
3. Wipe biodiesel spills from painted surfaces immediately as it will dissolve some paints.
These effects are greatly reduced or eliminated in blends of 20% or less. (B20, B5, B2, etc.) B20
filter changes happen in 2% of cases when first starting up, B2 has seen no changes to filter
performance. For those petroleum organizations planning on using an older diesel fuel or heating
oil tank with years of accumulated sediment (tank bottoms) it is highly recommended to clean
bottoms before introducing neat biodiesel.
B100 Material Compatibility 8
B100 may degrade some hoses, gaskets, seals, elastomers, glues and plastics with prolonged
exposure. Natural or nitrile rubber compounds, polypropylene, polyvinyl, and Tygon materials
are particularly vulnerable. More testing is being done to extend this list of vulnerable materials.
Most elastomers used after 1993 and are compatible with B100 (Viton/Teflon.) Contact the
equipment vendor to determine compatibility with fatty acid methyl esters before handling or
using neat biodiesel (B100.).
Biodiesel blends of 20% or less have shown a much smaller effect on these materials. The effects
are virtually non-existent in low-level blends such as B2. Normal monitoring of hoses and
gaskets for leaks is sufficient when handing blends of B20.
6
Tyson, Shaine. 2004 Biodiesel Handling and Use Guidelines. Department of
Energy/NREL. DOE/GO 102004. September 2004: Page 25
7
“Biodiesel Myths and Facts.” National Biodiesel Board: www.biodiesel.org, 2001
8
“B100 Material Compatibility.” National Biodiesel Board: www.biodiesel.org,
December 1997.
21
Teflon, Viton, and Nylon have very little reaction to biodiesel and are among the materials that
can be used to update incompatible equipment. B100 suppliers and equipment vendors should be
consulted to ensure the most recent findings on compatibility. It is highly recommended that bulk
biodiesel fuel handlers speak with hose suppliers to source hoses that are compatible with neat
biodiesel.
Most tanks designed to store diesel fuel will be adequate for storing B100. Acceptable storage
tank materials include aluminum, steel, fluorinated polyethylene, fluorinated polypropylene,
Teflon, and most fiberglasses.
Brass bronze, copper, lead, tin, and zinc may catalyze the oxidation process of biodiesel creating
fuel-insoluble gels and salts. Lead solders and zinc linings should be avoided, as should copper
pipes, brass regulators, and copper fittings. Affected equipment should be replaced with stainless
steel, carbon steel, or aluminum. Blends of B20 and lower reduce the impact of material
compatibility issues. (For a more comprehensive list of materials visit www.biodiesel.org, click
fuel facts, click materials of construction).
Underwriters Laboratory and other certification organizations are currently evaluating biodiesel
material compatibility. Please reference UL’s website for up-to-date list of approved products,
http://www.ul.com/
Table 5: Summary of Hardness and Swell Characteristics
Material
Effect of Biodiesel
Teflon
Nylon 6/6
Nitrile
Little change
Little change
Hardness reduced 20%
Swell increased 18%
Little change
Little change
Little change in hardness
Swell increased 7%
Little change in hardness
Swell increased 6%
Hardness reduced 10%
Swell increased 8-15%
Viton A401-C
Viton GFLT
Fluorosilicon
Polyurethane
Polypropylene
Enhanced Lubricity 9
Historic Data on Lubricity
Lubricity describes how a fuel lubricates the fuel system and engine. Enhanced lubricity benefits
equipment and will lead to fewer system problems and longer equipment life.
9
Howell, Steve. MARC-IV LLC. “Lubricity Test at William Pipeline Laboratory.” 1999
22
Figure 2: Lubricity of ULSD/Biodiesel
Blends
Ultra-low Sulfur Diesel
HFRR WSD (micron)
Traditionally diesel fuel was lubricated
primarily with sulfur. However, the combustion
of sulfur leads to sulfur dioxide – the primary
component of acid rain. This environmental
concern led policymakers to require sulfur
reductions in diesel fuel by 2006.
Historic lubricity testing has demonstrated that
biodiesel is extremely effective in increasing
the lubricity in diesel fuel. Blends containing
less than 1% biodiesel have shown significant
increases in fuel lubricity. B2 has been shown
to have up to 66% more lubricity than No. 2
diesel fuel. These graphs depict the lubricity
effects of biodiesel on various pilot batches of
ultra low sulfur diesels. Blends of 2%
biodiesel have been proven adequate in most cases.
800
700
600
500
400
300
200
100
0
0.0
1.0
2.0
3.0
4.0
5.0
Biodiesel Blend (%)
Current Lubricity Testing
Existing information on biodiesel impact with ULSD is very positive, even with the poorest
quality fuels. The NBB is conducting a survey of current market ULSD (fall of 2007) with a
wide variety of ultra low sulfur diesel fuels. That survey is still in progress at the time of the this
report but preliminary results show similar lubricity improvements as was demonstrated
previously: The addition of 2% biodiesel to any diesel fuel appears sufficient to bring even the
poorest lubricity diesel fuel into stringent Fuel Injection Equipment manufacturers
recommendations.
Cold Weather Performance
Biodiesel cold weather properties require careful attention when dealing with the product in cold
climates. It is extremely important to be familiar with the cold weather properties of both
biodiesel and the generic diesel intended for blending before handling the fuels.
Blends of biodiesel will impact cold weather operability in direct relationship to the independent
base analysis of the fuels being blended to create B2, B5 and B20. Therefore, the cold filter
plugging point, cloud point and pour point of both D975 and ASTM D6751-07a generic fuels
requires the attention of the blender.
The same precautions taken with petrodiesel can be used to insure trouble-free operations with
biodiesel. Traditional cold weather solutions for diesel work well with biodiesel except for
commercial cold flow additives designed for conventional diesel. These solutions include
kerosene blending, block and filter heaters and indoor garaging of vehicles when possible.
Although some additive suppliers claim to have products that work with biodiesel, it is more
likely that these products impact the generic diesel cold flow characteristics and not the neat
biodiesel.
23
Terminal companies that are storing biodiesel in its neat form will need to heat their tanks,
piping and associated delivery equipment to accommodate the pour point of biodiesel. The pour
point varies by feedstock. 10 Today the most common biodiesel feedstock being used to
manufacture ASTM D 6751 biodiesel has been soy which has a cloud point of 36° F and a pour
point of 30° F. Keeping the biodiesel heated to 50° F to 60° F is recommended until it can be
determined that it has been satisfactorily blended into the distillate product.
It is vital to adhere to the lowest operating temperature of the diesel fuel (CFPP or LTFT) prior
to accepting blends of biodiesel. When compared to conventional diesel fuel, B20 could decrease
operational temperatures by 7° F to 10° F. However, this value will be totally dependent on the
biodiesel feedstock being used. As a user of diesel fuel and biodiesel blends you are ultimately
responsible for advising your supplier what operability value you are seeking. For example, if
you need to operate to -10F in January and February your supplier will need to ensure that the
base diesel which is blended with biodiesel is a minimum of -20F before blending in the 20%
biodiesel.
Anticipating that a temperature compromise of up to 10F is likely (with soy based biodiesel,
more if tallow, grease or palm is used) you would then net down to -10F as a blended fuel. Your
supplier will need to source the most desirable base stock (based on the fuels cold filter plugging
point) blended with a combination of kerosene and a judicious dose of a competent and proven
cold flow additive designed to reduce the generic fuel operability which will make room for the
biodiesel percentage.
Biodiesel and Original Equipment Manufacturers (Warranties)
All diesel engine companies warranty the product they make - engines. They warranty their
engines for “materials and workmanship.” If there is a problem with an
engine part or with engine operation due to an error in manufacturing or
assembly within the prescribed warranty period, the problem will be
covered by the engine company.
Typically, an engine company will define what fuel the engine was
designed for and will recommend the use of that fuel to their customers in
their owner's manuals.
Engine companies do not manufacture fuel or fuel components. Therefore,
engine companies do not warranty fuel - whether that fuel is biodiesel or petrodiesel fuel. Since
engine manufacturers warranty the materials and workmanship of their engines, they do not
warranty fuel of any kind. If there are engine problems caused by a fuel (again, whether that fuel
is petrodiesel fuel or biodiesel fuel) these problems are not related to the materials or
workmanship of the engine, but are the responsibility of the fuel supplier and not the engine
manufacturer. Any reputable fuel supplier (biodiesel, petrodiesel, or a blend of both) should
stand behind its products and cover any fuel quality problems if they occur.
10
Biodiesel Cold Weather Blending Study. Cold Flow Consortium, July 2005, page 19.
24
Therefore, the most important aspect regarding engine warranties and biodiesel is whether an
engine manufacturer will void its parts and workmanship warranty when biodiesel is used, and
whether the fuel producer or marketer will stand behind its fuels should problems occur.
Most major engine companies have stated formally that the use of blends up to B20 will not void
their parts and workmanship warranties. This includes blends below 20% biodiesel, such as the
2% biodiesel blends that are becoming more common. Some engine companies have already
specified that the biodiesel must meet ASTM D-6751 as a condition, while others are still in the
process of adopting D-6751 within their company or have their own set of guidelines for
biodiesel use that were developed prior to the approval of D6751. It is anticipated that the entire industry will incorporate
the ASTM biodiesel standard into their owner's manuals over
time. Check with your engine manufacturer for their current
warranty information. (Websites for some engine
manufacturers are provide in Appendix 9.)
The National Biodiesel Board, the trade association for the
biodiesel industry, has formed the National Biodiesel
Accreditation Commission (NBAC) to audit fuel producers and
marketers in order to improve the quality of biodiesel
production and handling throughout marketing channels in the
U.S. NBAC issues a 'Certified Biodiesel Marketer' seal of approval for biodiesel marketers that
have met all requirements of fuel accreditation audits. The purpose of this seal of approval is to
provide added assurance to customers, as well as engine manufacturers, that the biodiesel
marketed by these companies meets the ASTM standards for biodiesel.
With biodiesel that meets the D-6751 specification, there have been over 50 million miles of
real-world operation with B20 blends in a wide variety of engines, climates, and applications. 11
The steps taken by the biodiesel industry to work with the engine companies and to ensure that
fuel meets the newly accepted ASTM standards provides confidence to users and engine
manufacturers that their biodiesel experiences will be positive and trouble-free.
Taxes and Incentives
A number of tax incentive programs have been implemented which will benefit the biodiesel
industry. The IRS has published on its website the various forms associated with the Volumetric
“Blender” Tax Credit. Forms are available by going to the Forms and Publications page of the
IRS website, www.irs.gov. A direct link to Form 637 is http://www.irs.gov/pub/irs-pdf/f637.pdf.
This form is the registration application that all biodiesel producers and blenders must complete.
Official registration may take a considerable amount of time so planning accordingly to meet
IRS deadlines is critical. For more information, contact the local IRS field office.
The Small Agri-Biodiesel Producer Tax Credit was established as part of the Energy Policy Act
of 2005. This tax credit program is a volumetric based income tax credit for the production of
agri-biodiesel (biodiesel made from first-use vegetable oils and first-use animal fats). At time of
11
Diesel Distributors Sell Soybean-Based Fuels Direct to Farmers. NBB Press Release
August 30, 2001.
25
publication, this credit has been extended to December 31, 2010 and can be found at
http://www.irs.gov/pub/irs-pdf/f8864.pdf
The Alternative Fuel Refueling Infrastructure Tax Credit was also established as part of the
Energy Policy Act of 2005. 12 This tax credit program provides a tax credit for the installation of
certain qualifying fueling infrastructure that dispense alternative fuel, including biodiesel blends
B20 and higher.
Environmental and Safety Information
13
Acute Oral Toxicity/Rates – Biodiesel is nontoxic. The acute oral LD 50 (lethal dose) is greater
than 17.4 g/Kg body weight. Table salt (NaCI) is nearly 10 times more toxic, by comparison.
However, as with all fuels, biodiesel should be handled with care.
Skin Irritation – Humans – A 24-hour human patch test indicated that undiluted biodiesel
produced a very mild irritation. The irritation was less than the result produced by a 4% soap and
water solution.
Aquatic Toxicity – A 96-hour lethal concentration for bluegill of biodiesel grade methyl esters
was greater than 1000 mg/L. Lethal concentrations at these levels are generally deemed
“insignificant,” according to the National Institute of Occupational Safety and Health (NIOSH)
guidelines in its Registry of the Toxic Effects of Chemical Substances.
Biodegradability – Biodiesel degrades about four times faster than petroleum diesel. Within 28
days, pure biodiesel degrades 85% to 88% in water. Dextrose, a test sugar used as the positive
control when testing biodegradability, degraded at the same rate. For example, blends of 20%
biodiesel and 80% diesel fuel degrade twice as fast as No. 2 diesel alone.
Flash Point – The flash point of a fuel is defined as the lowest temperature at which the vapor
above a combustible liquid can be made to ignite in air. The biodiesel flash point is more than
260° F, well above petroleum-based diesel fuel’s flash point, which is about 125° F. Testing has
shown the flash point of biodiesel blends increases as the percentage of biodiesel increases.
Therefore, biodiesel blended with ULSD is safer to store, handle, and use than diesel fuel.
12
“Small Agri-Biodiesel Producer Tax Credit.” Energy Policy Act of 2005, Section 1345.
Environmental and Safety Information Sheet. National Biodiesel Board,
http://www.nbb.org/pdf_files/Environment_Safety.pdf.
13
26
Housekeeping for Biodiesel and Middle Distillates14
It is imperative to ensure an optimum storage environment for all fuels. Air, water and insoluble
materials in the fuel itself are the three primary contaminants that can affect fuel. Controlling
these contaminants will minimize their effect on the fuel, whether middle distillates, biodiesel or
a blend of both.
Air
Air will enter through the vent pipe to displace fuel
in the tank as it is emptied. The excess air in the
tank may lead to increased oxidation, particulate
contamination, and increased water levels.
These contaminants affect both the stability and
quality of the fuel. In order to limit the effects
of air, it is recommended that fuel handlers do
not store fuels without stabilizers for long
periods of time in partially empty tanks. The use
of desiccant filters to reduce moisture and
particulate contamination might also be
considered.
Figure 3: Air Flow Diagram
Water
Both free and entrained water accelerate corrosion and fuel degradation. Free water may enter
bulk fuel tanks via condensation, carry-over from the fuel distribution system, and leakage
through the fill cap, spill containment valve, or piping. Microbial activity, surfactants, alcohols,
particulates, and poorly designed additives may be the cause of entrained water problems. In
addition to the accelerated breakdown of the fuel product, water also creates a fertile growing
environment for microbial contamination. Poor tank design has made complete removal of water
nearly impossible. Therefore, it is important to take steps to reduce it. Mechanical engineers can
determine strategies for optimizing tank farms for those that may be experiencing water
contamination.
Fuel Contaminants
Stored fuel may form insoluble materials which plug filters, foul injectors and form combustion
system deposits which all promote fuel system corrosion. Fuel often is contaminated with sand,
salt, dirt and other particles through the delivery process. Poor housekeeping practices will
increase operational headaches, which ultimately will result in more time and money spent.
Sticking tanks periodically with water-finding paste and addressing accumulating water by
drawing down water levels in tanks will go a long way in preserving the quality of stored fuels.
14
Interview with Howard Chesneau. President, Fuel Quality Services Inc., Flowery
Branch, Georgia. Edited ASTM STP-1005, Distillate Fuel Contamination Storage and Handling.
1987. Serves as speaker for SAE, Edited Chapter 3, Manual 45, ASTM. Serves on Board of
Directors for International Association of Storage and Handling.
27
Later in this publication there is a comprehensive listing of additive components designed to
address specific deficiencies inherent in stored liquid fuels of all types (Addressing Fuel Quality
Deficiencies with Additives). The deficiencies listed do not affect just biodiesel. Petroleum
handlers have for decades faced numerous quality challenges resulting from poor storage and
handling of fuels. The listing of additives is not meant to recommend any specific brand
additive, only the component which many additive manufacturers and distributors may use to
resolve the deficiency from which your fuel may be suffering.
Storage Tank Challenges
Distribution chain storage tanks present a challenging maintenance process for fuel handlers.
Improper placement of water draw-off can lead to accumulation of water in the system. Lack of
attention to water evaluation may exacerbate this problem. Electronically or physically sticking
the tanks with water-finding paste before and after each fuel delivery is a must.
Maintaining Fuel Quality
•
Specify ASTM approved fuels only. (See appendix) ASTM
D975 (generic diesel) ASTM D396 (heating oil) and ASTM
D6751-07a (biodiesel)
• Reference cold weather performance and other special needs
prior to ordering. (Please refer to the section on Fuel
Properties.)
• Be proactive with general housekeeping practices.
• Execute a monthly or quarterly fuel analysis program to
ensure the safe keeping of fuels.
• Adhere to BQ-9000 program directives. www.bq-9000.org
Key Points for Transporting Biodiesel
•
•
•
•
•
•
15
Use aluminum, carbon steel, or stainless steel
containers during transport.
Implement proper inspection and/or washout
of transport.
Check for previous load carried and any
residuals.
Food products or raw vegetable oil, gasoline,
and lubricants are not acceptable residuals.
Make sure there is no residual water in
transport.
Make sure hoses and seals are clean and
compatible with B100.
15
Tyson, Shaine. 2004 Biodiesel Handling and Use Guidelines. Department of
Energy/NREL: DOE/GOV–102004-1999, September 2004, page 27.
28
•
Determine the need for insulation or method of heating the transport if shipping during
winter months.
Placards are a critical source of hazard information. They are part of an internationally
harmonized system of communicating the dangers inherent in the transportation of hazardous
materials. They also play a critical role in communicating the presence of hazardous materials to
emergency responders, transport workers and regulatory enforcement personnel in the event of
an incident.
Current placarding requirements are diamond-shaped (square-on-point) signs that are used to
identify shipments of hazardous materials. When the use of placards is required, they must be
placed on both ends and both sides of trucks, railcars, and intermodal containers that carry
hazardous materials. They are coded by color and contain symbols and numbers that designate
the hazard class or division of the hazardous material being shipped. For bulk and certain nonbulk shipments, a four-digit hazardous material identification number may be on the placard or
on an accompanying orange panel or a white square-on-point sign. 16
Placards are required for the transportation of hazardous materials, based on the type and
quantity of material. Federal law defines hazardous material as:
“A substance or material that the Secretary of Transportation has determined is capable of
posing an unreasonable risk to health, safety, and property when transported in commerce, and
has designated as hazardous under…Federal hazardous materials transportation law.” 17
Hazardous materials are broken into nine hazard classes:18
1.
2.
3.
4.
5.
6.
7.
8.
9.
Explosives
Gases
Flammable and combustible liquids
Flammable solids, spontaneously combustible materials, and dangerous when wet
materials
Oxidizers and organic peroxides
Toxic (poison or poisonous) material and infectious substances
Radioactive materials
Corrosive materials
Miscellaneous dangerous goods (HMR, Title 49 CRF Part 172.504)
16
“Role of Hazardous Material Placards in Transportation Safety and Security.” Executive
Summary. U.S. Department of Transportation, Research and Special Programs Administration.
January 15, 2003.
17
HMR, Title 49 CRF Part 171.8
18
Role of Hazardous Material Placards in Transportation Safety and Security.” U.S.
Department of Transportation, Research and Special Programs Administration. January 15, 2003.
Page 6.
29
Placards are necessary if the flash point is under 200° F. Placards would not be required for raw
vegetable oil or neat biodiesel (B100) because the flash point for biodiesel is 266° F. In lieu of
testing each blend for flash, distributors of B20 or other blends should use the existing placards
1993 or 1223, to cover themselves. For the biodiesel producer interested in the one gallon of
diesel into the 999 gallons of biodiesel (a 99.9% blend) it is unlikely that the biodiesel should to
be adulterated to the point of pushing it down under the 200 F range, hence making placarding
these blends (for tax purposes) not necessary.
The HMIS/NFPA Hazard Rating – which is shown in the right corner of our sample MSDS sheet
on biodiesel (Appendix 1) – is 0-1-0 (1) being the fire rating (0), for health risk, and (0) for
reactivity. Standard No. 2 fuel oil or diesel is 1-2-1. This placard blue/red/yellow symbol has
nothing to do with the Hazmat placarding system. The HMIS/NFPA Hazard Rating is about the
Occupational Safety and Health Administration and the National Fire Protection Agency.
Key Points for Storage of Biodiesel
•
•
•
•
•
•
•
Acceptable storage tank materials include aluminum, steel,
fluorinated polyethylene, fluorinated polypropylene, Teflon,
and most fiberglass. 19
Do not store B100 for long periods of time in systems
containing reactive metals.19
B100 should be stored at temperatures at least 10° F higher than the cloud point.
Generally, storage temperatures of 45° F to 50° F are acceptable for most B100, although
some B100 fuels may require higher storage temperatures. Therefore, most underground
storage facilities are adequate, but aboveground fuel systems should be protected with
insulation, agitation, heating systems or other methods, depending on the climate. 20
B100 is a mild solvent, so carefully clean the tanks and fuel system where any sediments
or deposits may exist. Prepare for more frequent filter changes while the system is
cleaned. 21
UL Test Certification of National Foam’s Aer-O-Foam XL-3, approved for extinguishing
Biodiesel Fuel Fires. Fire tests were conducted in accordance with UL Standard 162,
Safety for Foam Equipment and Liquid Concentrates, 7th edition revised, 9-8-1999.
Both Kolor Kut and Sar Gel water finding pastes are effective at detecting water in
biodiesel and biodiesel blends. Use of stick and water finding paste is absolutely the most
effective tank management protocol available. Tanks should be evaluated before and after
each fuel receipt to ensure that no water arrived with the fuel delivery.22
API RP 1637 color marking system has been established for B100 and associated blends.
This marking system helps designate the contents of tanks and piping which carries it to
19
“Materials Compatibility.” National Biodiesel Board, www.biodiesel.org.
Biodiesel Cold Weather Blending Study. NBB and the Cold Flow Consortium, July
2005, page 6.
21
Biodiesel Myths and Facts. National Biodiesel Board, www.biodiesel.org. 2001
22
Nazzaro, Paul and Hoon Ge. Water Finding Paste and Biodiesel Blends. Advanced Fuel
Solutions and MEG Corp. Hoon Ge. August 2006.
20
30
the loading rack. API has approved the following symbol for use with biodiesel and
biodiesel blends: Yellow hexagon outer bank with bronze hexagon inside with either
white or back font for designated blends as well as B100. These colors will be used at the
service station level as well.
Blending B-100
The chemical makeup of biodiesel makes it compatible for blending with any kind of distillate.
The blending can occur in any ratio with petroleum diesel from additive levels to 100%
biodiesel. The blend is identified using B followed by the percentage of biodiesel in the finished
product in “Bxx” form. Common blends include B2, a 2% biodiesel blend, which is often used
for added lubricity, and B20, a 20% biodiesel blend, which is the minimum blend level that can
be used by fleets covered by the Energy Policy Act of 1992.
Preparing to Blend Biodiesel
•
•
•
•
Establish storage and injection points suitable for larger terminals,
smaller jobbers, and some retail outlets.
Evaluate each terminal individually because different
requirements will be necessary to ensure seamless operation at
each terminal.
Coordinate with biodiesel suppliers for best delivery methods and
scheduling when sizing tank capacity.
Address on-site storage challenges for biodiesel.
Blending Strategies
Splash Blending
Biodiesel and diesel fuel are loaded separately. Mixing of the products occur as the fuel is
agitated through blending of each fuel, as well as agitation during transport and delivery to the
end user. It is recommended that because biodiesel is slightly heaver than conventional distillates
it be loaded second when top loading to eliminate the biodiesel from settling to the bottom of the
blending tank. When bottom loading is utilized, the fuel flow may be adequate to load either fuel
first with no negative consequences due to the minor viscosity differentials.
In-Tank Blending
Biodiesel and diesel are loaded separately – or in some cases simultaneously through different
incoming sources – but at a high enough fill rate that the fuels sufficiently mix so that no further
agitation is necessary.
31
In-Line Blending
Biodiesel is added to a stream of diesel fuel as it travels through a pipe or hose. The blending
occurs as the two products move through the pipe or once the fuel is loaded into its receiving
vessel.
Rack Blending
Injected directly at the rack into the tank truck, similar to adding performance fuel additives and
red dye.
Biodiesel is fully compatible with petroleum diesel, and therefore blending biodiesel is not
difficult. However, regardless of the blending strategy, it is important to understand some of the
significant characteristics of biodiesel. Some of these characteristics are:
•
•
•
Biodiesel is heavier than diesel fuel. Biodiesel has a specific gravity of 0.88
compared to No. 2 diesel at 0.85 and No. 1 diesel at 0.80. It is therefore
recommended that the generic distillate fuel be in the tank prior to introducing the
biodiesel. Biodiesel should be blended on top of the petroleum diesel when splash
blending.
Biodiesel has a high pour point. It may be necessary to heat the biodiesel depending
on the outside temperature to ensure flow prior to the introduction of the generic
distillate portion of the blend.
Blends will not separate in the presence of water. Execute proactive tank
management to prevent other problems caused by excess water.
Cold Weather Blending
Biodiesel has a pour point of approximately 30° F and therefore requires heating to ensure flow
prior to the introduction of the generic distillate portion of the biodiesel blend. The cold flow
performance of the finished product may be impacted between 3° F and 10° F for a B20 blend,
less for B2 and B5, once the biodiesel is blended into the generic distillate. Knowing what is
being purchased – based on fuel specifications provided by the fuel supplier as it relates to the
generic percentage of the biodiesel blend – is critical. The lower the winter operability
temperatures of the generic distillate that will be blended with the biodiesel, the more reliable the
blended fuel will be in different regions.
Blended fuels can be stored below ground in most climates. Above ground storage for both
generic distillates and biodiesel should be protected with insulation, agitation, kerosene blends,
heating systems or other measures if freezing weather is common. These precautions should also
be used to protect tank piping and pumping equipment. These cold weather preparatory
recommendations are equally important when storing conventional distillates as well as biodiesel
and biodiesel blends.
Generic distillates are commonly loaded onto fuel trucks at oil terminals at temperatures as low
as 19° F. Fuel handlers will be blending cold diesel fuel with warm biodiesel when biodiesel
32
requires heat protection to at least 10° F above the cloud point of the fuel. 23 Input has been
solicited from fuel handlers as to independent blending strategies in an effort to develop
recommended “best practices” to achieve successful blending and distribution.
While some feedback indicates no problems with fuel temperature differentials, other
information suggests fuel handlers have seen the saturated compounds in the biodiesel crystallize
and plug fuel filters and lines. The effects have been similar to generic distillate fuel that see
temperatures equal to or lower than its cloud point. To circumvent the potential for this problem,
it is recommended that the following guidelines be observed when blending biodiesel with
generic distillates:
Cold Weather Blending Guidelines
•
•
•
•
•
•
•
23
Blend the biodiesel with 50% kerosene prior to introducing it into the final fuel mixture.
Make sure that the kerosene is above 45° F, if possible.
Absolutely know the cloud point, cold filter plugging point and pour point of the generic
diesel fuel product prior to blending. This will help determine the possible effect of the
biodiesel blend on the key winter operability characteristics post blending. If the process
is begun with inferior generic distillate cold weather specifications, the result will end
with an inferior biodiesel blended fuel as well.
Seek higher blending speeds through gravity distribution or mechanical agitation, at least
75 gallons per minute to full rack velocity, which can be as high as 650 gallons per
minute. Hand mixing – pouring one fuel into another – is not suggested in cold climates.
Alternatively, once the truck has been loaded at a bulk terminal the product could then be
pumped or gravity dropped into the end users’ fuel storage tanks. This blend strategy has
proven successful. (Note: Optimum blending of fuels results from appropriate terminal
blending under automated equipment utilization.)
Neat biodiesel should not be kept on a truck overnight prior to delivery.
Many fuel users and distributors currently use cold winter diesel fuel additives to
improve winter handling characteristics of diesel fuel. No commercial diesel fuel additive
has to date been found effective in modifying the cold weather specifications of neat
biodiesel. However, commercial additives are available to treat the generic distillate
portion of the blend, which can aid in reducing the cold weather characteristics of the
fuels’ pour point and cold filter plugging point. That will benefit the biodiesel blend by
working solely on the distillate fuel characteristics. (Remember that the lower the pour
point, cloud point and cold filter plugging point of the distillate fuels the better the
biodiesel blend will be.)
It is imperative that cold weather distillate additives be added to the fuel before the fuel
reaches its cloud point. It is also essential that the additive get into the fuel when agitation
is available through the chosen blending strategy. As with biodiesel blending, an additive
requires equal blending attention to ensure that it is distributed evenly throughout the
tank to obtain optimum winter performance characteristics.
Only use fuels that meet ASTM specifications. Biodiesel needs to meet or exceed ASTM
D6751 while generic diesel must meet or exceed ASTM D975. Absolutely do not blend
fuels that do not meet the respective specifications.
Biodiesel Cold Weather Blending Study. Cold Flow Consortium, July 2005, Page 2.
33
•
•
•
•
Become acquainted with the local fuel-testing laboratory in the region before a problem
arises. Ask the laboratory to provide pre-labeled testing kits to use when submitting
samples for quality testing evaluations.
Stick all tanks storing biodiesel, generic distillates, and combinations for both fuels for
water by using a gauge stick and water-finding paste, which is available at petroleum
supply houses.
It is recommended that 30-micron filters be used on filters utilized for fuel pumping
islands whenever possible. Winter conditions frequently cause fuel to haze when fuels
reach posted cloud points, and the entrained moisture tends to freeze causing premature
filter plugging. Operators of vehicles using 5-micron or 6-micron filters should consider
switching to a large micron filter during extreme winter conditions.
Water-fuel separators need to be checked at the time vehicles are being fueled and must
be serviced as often as necessary.
Infrastructure considerations 24
There will not be a best single way to blend B2 to B100 by using one method for the complete
range at the loading rack. Utilize current assets the best way possible. Select storage and
blending options that are appropriate and can be supported by existing equipment.
To accommodate B2 to B5 with product flow rates of 600 gallons per minute the pump and
supply line will handle the demand of the total volume for all load arms with sufficient pressure.
Blend ratios in this range will require a larger injection point – typically a two-inch opening.
Consideration must also be given to power requirements for the larger motors required for this
blending ratio.
B2 to B5 distributed with a product flow of 600 gallons per minute will require a meter and valve
rated for 12 GPM minimum while B5 will require a 30 GPM system. These ranges are
achievable with current high capacity meter-based injectors found in many terminals nationwide.
High capacity meter-based injectors will allow accurate control and metering up to 5% blending.
Blending biodiesel in ratios of 10% and above will require a
higher level of infrastructure to achieve this goal. B10 and
above will be more invasive as it pertains to physical space
required by this equipment. However, this blend percentage
will be achieved by using sequential blending with or
without automation or preset ratio blending depending on
automation only. (See below)
Sequential blending means basically loading one product at a time using the same meter for both
products – biodiesel and generic rack diesel. Both products can also use one common control
valve. However, a block valve for each product will be necessary.
24
Paul Hinkle, ASI Engineering, Broken Arrow, Oklahoma, Paul J. Nazzaro, Advanced
Fuel Solutions, Inc. A collaboration on infrastructure development, 2006
34
Sequential blending typically is the least intrusive and least expensive to add to existing
terminal infrastructure. It is really a matter of adding a new product to a loading lane at the truck
terminal facility. The ultimate result is enabling a terminal operator to load multiple products at
one loading position or at different rack positions through different loading arms.
Preset true ratio blending enables terminal operators to load both products (biodiesel/diesel
fuel) at the same time. One meter and control valve per product is required and the blend stays
proportional and blends throughout the complete load.
Preset batch ratio blending activates both products
simultaneously and is loaded at the same time. Like the preset true
ratio concept, one meter and control valve per product is required
but flow ratios are not controlled proportionally. That means the
product with the lesser volume may finish substantially earlier
than the larger product volume.
Blending systems like a 4-arm blender engineered to work with
rack presents can be built to work within your specific space requirements. They are normally
designed in a horizontal configuration, but often are designed in vertical configurations to fit in
tighter space requirements.
V-Port ball valves allow for more accurate controls of the product stream at different rates and
are enabled with hydraulic actuators. Again, if space restrictions at terminals are an issue,
multiple arms per bay blenders can be designed and installed at the end of each respective truck
bay to accommodate tight spots.
Distribution goals should be determined prior to developing infrastructure upgrade plans to
successfully blend biodiesel into generic fuel streams. There are many mechanical engineering
companies strategically located throughout the nation that are qualified to tour facilities and
make recommendations on how best to accomplish intended goals.
Each blending method (and its required infrastructure) has many positives and negatives. The
blending method must fit to both current and future needs, while remaining cost effective. Shown
below is an analysis of each of the blending options, positive and negative aspects as well as an
approximate cost analysis based on actual nationwide installations.
NOTE: Recommendations based on recent installations managed by ASI Engineering, a Broken
Arrow Oklahoma mechanical engineering company. The following recommendations and values
are based on experiences which ASI encountered with field projects over the past several years.
It is highly recommended that these recommendations and values be used only as guidelines
during developmental processes. It is a good practice to seek the guidance of a reputable
engineering company to develop solutions to individual situations.
35
Figure 4: Estimated Cost Comparisons of Biodiesel Infrastructure Options
Recommendations for Blending at Retail Locations (Option 1)
•
•
Injecting into distillate at retail locations without automation systems and other
limitations.
This system is currently used at many retail outlets to inject cold flow improver into fuel.
Allows for accurate reconciling of blended fuel.
This system adds the Biodiesel automatically and proportionately as the fuel is dropped
into the storage tanks at the retail outlet from the transport.
Can be accessed remotely by modem.
•
Positives
Most economical for small scale operations
•
•
•
•
Negatives
Numerous moving parts, one system per location
Minimal documentation
More hands-on involvement
No method to test and make corrections to blend
•
•
•
36
Pricing
Tank Sized for 500K Gallons Month
1
10,000 Gallon Double Wall AST includes level
gauges, valves, etc.
Dual Pump/ Motor Skid
Injector per storage tank
Tank fill adapter, meter, valves, etc.
Insulation for tank
Tank Heaters
Mixer not needed, pump will circulate
Installation of complete system/storage tank
includes mech., elec., and civil/tank
Total
1
1
1
1
1
1
$50,000
$14,000
$6,000
$4,500
$4,000
$7,500
$10,000
$96,000
Recommendations for Blending at Jobber Locations (Option 2)
•
Injecting into distillates at jobber locations without automation systems and other
limitations.
Positives
•
Economical
Negatives
•
•
•
Requires human involvement during blending process
Potential for inaccurate loads
Minimal documentation of loads
Pricing
Tank Sized for 500K Gallons / Month
1
1
1
1
1
1
10,000 Gallon Double Wall AST includes level
gauges, valves, etc.
Biodiesel Loading/Metering Skid (30 GPM)
Insulation for tank
Tank Heaters
Concrete Pad for tank
Installation of tank and equipment
Total
$50,000
30,000
$10,000
$9000
$8,000
$25,000
$132,000
37
Recommendations for Tank Farm Blending Sequential / Splash Batch Blending
(Option 3)
•
•
•
•
•
•
•
1
1
1
1
1
1
1
1
1
Positives
Cost effective and operationally sound.
Allows Biodiesel to be transferred into distillate tankage when all distillate is to
be blended with Biodiesel.
Biodiesel can be loaded directly into the storage tank prior to, during, or after
delivery.
For optimum blending the Biodiesel can be injected proportionally into the
distillate pipeline upstream of tankage.
Minimal capital investment allows accurate accountability with the ability to
perform lab analysis on, and make corrections to the actual blend before loading
transports.
Negatives
All distillate in selected storage tanks has been blended and cannot be sold as
unblended to locations not desiring Biodiesel blended distillate, i.e. exporting.
The tank may need to be circulated to maintain suspension of Biodiesel depending
on turnover duration and temperature of fuel.
Pricing
Tank Sized for 1.5M Gallons / Month
30,000 Gallon AST (Vertical or Horizontal)
$60,000
Heated and Insulated
$20,000
Foundation
$15,000
Insertion Heaters
Feed Pump for Biodiesel (20 GPM P/D)
Flow Meter (20 GPM) 4-20 mA for Biodiesel
Mainline Flow Meter
Misc. Valves, Check Valves, etc.
Installation Construction
Civil, Mechanical, and Electrical
Total
38
$9000
$20,000
$3,000
$5,000
$3,000
$55,000
$190,000
Recommendations for Truck Loading Terminals Sequential Blending at the Rack
(Option 4)
•
•
•
•
•
•
•
•
•
Positives
Cost effective / operationally sound strategy to blending individual loads.
Allows Biodiesel to be loaded and metered at a flexible proportionate rate, with
the fuel loading afterward. Allows use of existing automation systems to perform
the blending, monitoring, and reconciling of the fuel mixture.
Allows rate changes to be easily performed in programming without future
equipment upgrades specific for this product.
Allows for Independent storage for the unadditized fuel to be loaded either with
or without Biodiesel.
If Biodiesel is desired, fuel volume will be selected as normal by the driver with a
selection of grade for Biodiesel.
The Biodiesel will be loaded into the truck first by volume entered in the presets,
and the distillate will be added at the end of the load proportionately. This will be
done by the existing automation system using the same loading arm.
Similar to the method commonly used for ethanol and mid-grade.
Operates by installing a Biodiesel line connection into the fuel loading line.
Flow will be controlled by a control valve and meter pulses to the automation
system or accuload.
Negatives
• B100 requires heat and insulation to all injection points and may slow loading
time at some locations, but by small amounts.
Pricing
Tank Sized for 1.5M Gallons / Month
1
1
1
30,000 Gallon AST (Vertical or Horizontal)
Heated and Insulated
Foundation
$60,000
$20,000
$15,000
1
Insertion Heaters
Feed Pump for Biodiesel (20 GPM P/D)
Flow Meter (20 GPM) 4-20 mA for Biodiesel
Control Valve
Misc. Valves, Check Valves, etc.
Installation Construction
Civil, Mechanical, and Electrical
Automation Upgrade/Bay
Total
$9,000
$20,000
$3,000
$5,000
$3,000
$55,000
1
1
1
1
1
39
$10,000
$200,000
Recommendations for Truck Loading Terminals Injecting at the Rack (Option 5)
•
Biodiesel is blended as a normal fuel additive proportionately as the fuel is loaded.
•
Positives
Terminal operators will be familiar with this type of system operation and
maintenance.
•
•
•
Negatives
Blend rates up to 5% proportional maximum optional.
Higher rates desired must slow loading of product.
Typically this is most affordable.
1
1
1
Pricing
Tank Sized for 1.5M Gallons / Month
50,000 Gallon AST (Vertical or Horizontal)
Dual pump/motor skid w/ 8-10 GPM pumps
Concrete Pad/ Containment
1
1
1
1
1
1
Insertion Heaters
Tank Farm Equipment Installation
Insulate AST
Injector, Tubing, Valves, etc. per load arm
Installation Injector Equipment/Load Arm
Includes electrical
1
Options:
Automation Upgrade/ Programming per Bay
Total
$80,000
$14,000
$15,000
$9,000
$40,000
$25,000
$8,000
$5,000
$10,000
$206,000
Sequential Blender Recommendations for Truck Loading Terminals Blending into
Distillates (Option 6)
•
•
•
Splash blending and wild stream blending to the rack.
Goal Accomplished by adding the same equipment as for sequential blending
Splash blending allows the biodiesel to be loaded concurrently with the distillate through
a common load arm.
40
•
Positives
Minimal interference with normal operations using equipment common in all
terminals.
Fuel is mixed throughout load while loading into transport.
•
Negatives
Installation and maintenance costs are increased versus sequential blending.
•
•
B100 requires heat & insulation to all blend connections.
Pricing
Tank Sized for 1.5M Gallons / Month
1
1
1
30,000 Gallon AST (Vertical or Horizontal)
Heated and Insulated
Foundation
$60,000
$20,000
$15,000
1
1
1
1
1
1
1
Insertion Heaters
Heated and Insulated 2” Line to the Rack
Feed Pump for Biodiesel (20 GPM P/D)
Flow Meter (20 GPM) 4-20 mA for Biodiesel
4” Control Valve
Misc. Valves, Check Valves, etc.
Installation Construction
Civil, Mechanical, and Electrical
Automation Upgrade/Bay
Total
$9000
$10,000
$9,000
$3,000
$5,000
$3,000
$65,000
1
$10,000
$209,000
Equipment Summary
There are several flexible options for meeting blending requirements for biodiesel. Each option
has several pros and cons as well as different budgeting implications.
Each terminal operator dictates the selected strategy. The strategy should be based on the needs
of the operator, the goals of the operation, and the constraints of the budget. Future flexibility
should also be considered.
Sizing storage tanks and controlling cold weather handling characteristics of biodiesel comprise
the majority of installation costs.
All costs outlined within this document are subject to change without notice. Publication
contributors projected costs as of September 2004. Mechanical engineering contractors can
provide more site-specific quotations.
41
Conclusion
Environmental concerns and a desire to increase U.S. energy independence are encouraging
transit agencies to look for alternatives to diesel fuel. Biodiesel is a promising alternative that
requires little, if any, modifications to today’s engines. However, transit agencies considering
the use of biodiesel need practical information on how to procure, handle, and use it. The report
provides transit agencies with best practices, including a fleet fuel procurement checklist (in
Appendix 3), to help them determine how to add biodiesel to their current operations and how to
avoid potential problems.
42
Appendix 1: Material Safety Data Sheet
1. CHEMICAL PRODUCT
General Product Name: Biodiesel
Synonyms: Methyl Soyate, Rapeseed Methyl Ester (RME),
Methyl Tallowate
Product Description: Methyl esters from lipid sources
CAS Number: Methyl Soyate: 67784-80-9; RME: 73891-99-3;
Methyl Tallowate: 61788-71-2
2. COMPOSITION/INFORMATION ON INGREDIENTS
This product contains no hazardous materials.
3. HAZARDS IDENTIFICATION
Potential Health Effects:
INHALATION:
Negligible unless heated to produce vapors. Vapors or finely misted materials may irritate the mucous membranes
and cause irritation, dizziness, and nausea. Remove to fresh air.
EYE CONTACT:
May cause irritation. Irrigate eye with water for at least 15 to 20 minutes. Seek medical attention if symptoms
persist.
SKIN CONTACT:
Prolonged or repeated contact is not likely to cause significant skin irritation. Material is sometimes encountered at
elevated temperatures. Thermal burns are possible.
INGESTION:
No hazards anticipated from ingestion incidental to industrial exposure.
4. FIRST AID MEASURES
EYES:
Irrigate eyes with a heavy stream of water for at least 15 to 20 minutes.
SKIN:
Wash exposed areas of the body with soap and water.
INHALATION:
Remove from area of exposure; seek medical attention if symptoms persist.
INGESTION:
Give one or two glasses of water to drink. If gastro-intestinal symptoms develop, consult
medical personnel. (Never give anything by mouth to an unconscious person.)
5. FIRE FIGHTING MEASURES
Flash Point (Method Used): 130.0° C min (ASTM 93)
Flammability Limits: None known
EXTINGUISHING MEDIA:
Dry chemical, foam, halon, CO2, water spray (fog). Water stream may splash the burning
liquid and spread fire.
SPECIAL FIRE FIGHTING PROCEDURES:
Use water spray to cool drums exposed to fire.
UNUSUAL FIRE AND EXPLOSION HAZARDS:
Oil soaked rags can cause spontaneous combustion if not handled properly. Before
disposal, wash rags with soap and water and dry in well ventilated area. Firefighters
43
should use self-contained breathing apparatus to avoid exposure to smoke and vapor.
6. ACCIDENTAL RELEASE MEASURES SPILL CLEAN-UP PROCEDURES
Remove sources of ignition, contain spill to smallest area possible. Stop leak if possible.
Pick up small spills with absorbent materials such as paper towels, “Oil Dry”, sand or dirt.
Recover large spills for salvage or disposal. Wash hard surfaces with safety solvent or
detergent to remove remaining oil film. Greasy nature will result in a slippery surface.
7. HANDLING AND STORAGE
Store in closed containers between 50°F and 120°F.
Keep away from oxidizing agents, excessive heat, and ignition sources.
Store and use in well ventilated areas.
Do not store or use near heat, spark, or flame, store out of sun.
Do not puncture, drag, or slide this container.
Drum is not a pressure vessel; never use pressure to empty.
8. EXPOSURE CONTROL /PERSONAL PROTECTION
RESPIRATORY PROTECTION:
If vapors or mists are generated, wear a NIOSH approved organic vapor/mist respirator.
PROTECTIVE CLOTHING:
Safety glasses, goggles, or face shield recommended to protect eyes from mists or
splashing. PVC coated gloves recommended to prevent skin contact.
OTHER PROTECTIVE MEASURES:
Employees must practice good personal hygiene, washing exposed areas of skin several
times daily and laundering contaminated clothing before re-use.
9. PHYSICAL AND CHEMICAL PROPERTIES
Boiling Point, 760 mm Hg:>200°C Volatiles, % by Volume: <2
Specific Gravity (H2O=1): 0.88 Solubility in H2O, % by Volume: insoluble
Vapor Pressure, mm Hg: <2 Evaporation Rate, Butyl Acetate=1: <1
Vapor Density, Air=1:>1
Appearance and Odor: pale yellow liquid, mild odor
10. STABILITY AND REACTIVITY
GENERAL:
This product is stable and hazardous polymerization will not occur.
INCOMPATIBLE MATERIALS AND CONDITIONS TO AVOID:
Strong oxidizing agents
HAZARDOUS DECOMPOSITION PRODUCTS:
Combustion produces carbon monoxide, carbon dioxide along with
thick smoke.
11. DISPOSAL CONSIDERATIONS
WASTE DISPOSAL:
Waste may be disposed of by a licensed waste disposal company. Contaminated
absorbent material may be disposed of in an approved landfill. Follow local, state and
federal disposal regulations.
12. TRANSPORT INFORMATION
44
UN HAZARD CLASS: N/A
NMFC (National Motor Freight Classification):
PROPER SHIPPING NAME: Fatty acid ester
IDENTIFICATION NUMBER: 144920
SHIPPING CLASSIFICATION: 65
13. REGULATORY INFORMATION:
OSHA STATUS:
This product is not hazardous under the criteria of the Federal OSHA Hazard
Communication Standard 29 CFR 1910.1200. However, thermal processing and
decomposition fumes from this product may be hazardous as noted in Sections 2 and 3.
TSCA STATUS:
This product is listed on TSCA.
CERCLA (Comprehensive Response Compensation and Liability Act):
NOT reportable.
SARA TITLE III (Superfund Amendments and Reauthorization Act):
Section 312 Extremely Hazardous Substances:
None
Section 311/312 Hazard Categories:
Non-hazardous under Section 311/312
Section 313 Toxic Chemicals:
None
RCRA STATUS:
If discarded in its purchased form, this product would not be a hazardous waste either by
listing or by characteristic. However, under RCRA, it is the responsibility of the product
user to determine at the time of disposal, whether a material containing the product or
derived from the product should be classified as a hazardous waste,
(40 CFR 261.20-24)
CALIFORNIA PROPOSITION 65:
The following statement is made in order to comply with the California Safe Drinking
Water and Toxic Enforcement Act of 1986. This product contains no chemicals known to
the state of California to cause cancer.
14. OTHER INFORMATION:
This information relates only to the specific material designated and may not be valid for such
material used in combination with any other materials or in any other process. Such information
is to the best of the company’s knowledge and believed accurate and reliable as of the date
indicated. However, no representation, warranty or guarantee of any kind, express or implied, is
made as to its accuracy, reliability or completeness and we assume no responsibility for any loss,
damage or expense, direct or consequential, arising out of use. It is the user’s responsibility to
satisfy himself as to the suitableness and completeness of such information for his own particular
use.
45
Appendix 2: EMA Consensus Position
EMA Consensus Position: Joint EMA/TMC Pump Grade Specification for
Premium Diesel Fuel
Purpose
This Consensus Position is intended to define premium diesel fuel marketed commercially at
retail fueling stations and truck stops.
It is the belief of the Engine Manufacturers Association (EMA) and The Maintenance Council
(TMC) that equipment users look to premium diesel fuel at the pump as a significant opportunity
for improving fuel-related performance issues or solving problems related to fuel. As such,
premium diesel fuel should be a fuel broad in scope, offering improvements in many areas so as
to satisfy the needs of as many end users as possible. The recommendations in the attached table
are intended to produce performance benefits that are noticeable to equipment users.
This diesel fuel recommendation is considered to be "premium" insofar as it may assist in
improving the performance and durability of engines currently in use and those expected to be
produced prior to 2004. It is not intended to enable engines to meet any emissions standard or, in
general, to improve exhaust emissions. Nor does it preclude centrally fueled fleets from
negotiating with their fuel supplier for fuel that they feel fits their unique needs. It is intended as
a "living document" in that, as other needs or test procedures are identified, the recommendation
will be upgraded.
The most significant aspects of this Consensus Position are its requirements for a minimum fuel
lubricity, increased cetane number, improved cold weather performance, detergency, thermal
stability, minimum energy content, and specifications regarding overall fuel "cleanliness". These
properties, described in detail below, should help address many current customer satisfaction
issues.
Significance and use of the recommended properties:
API Gravity or Energy Content
API Gravity is a measure of a fuel’s density – or weight per gallon. The higher the API gravity,
the less a gallon of fuel weighs and the less energy it contains. API gravity of diesel fuel has a
profound effect on engine power. As a general rule, a 3% to 5% decrease in the thermal energy
content will result in roughly the same percentage decrease in engine power. Use of fuels with
higher API gravity will also result in higher fuel consumption – lower miles per gallon. Our
recommendation includes a maximum API gravity based on equipment the user needs to
maintain engine power, while minimizing fuel consumption. As an alternative, this Consensus
Position includes an equivalent minimum energy content specification to help ensure acceptable
performance.
46
Low Temperature Operability
Several tests are commonly used to characterize the low temperature operability of diesel fuel.
These are Cloud Point, Low Temperature Flow Test (LTFT), and Cold Filter Plugging Point
(CFPP). Among these, the LTFT provides the best overall correlation with field performance.
However, for fuel without additives, Cloud Point and LTFT correlate very well. Since Cloud
Point is more practical as a quality control test, it is listed as the primary recommendation.
ASTM does not recommend CFPP as an indicator of low temperature operability. However, if
data emerges to show universal correlation with the recommended procedures for all vehicle
types, EMA/TMC will consider including that procedure in a future version of this Consensus
Position.
Actual temperature targets should be adjusted monthly based on latitude using ASTM D975 10th
percentile minimum ambient temperature data. EMA and TMC agree with the Canadian
approach in recommending 2.5 percentile temperature for cold flow properties as providing the
necessary protection for a “premium” grade fuel. Since 2.5 percentile data is not available in the
United States, setting the recommended level 4° C below the 10th percentile is designed to
approximate the 2.5 percentile level of protection.
Cetane Number/Cetane Index
Cetane number is a relative measure of the interval between the beginning of injection and auto
ignition of the fuel. Cetane number is a year-round concern. A higher number means a shorter
delay interval. Fuels with low cetane numbers will cause hard starting, rough operation, noise
and increased smoke opacity. Current commercial fuel cetane requirements may not adequately
address these customer satisfaction issues.
Generally, diesel engines will operate better year-round on fuels with cetane numbers above 50,
compared to fuels with cetane numbers of the national average of approximately 45. Fuel
suppliers may increase the cetane number through the refining process or the blending of
combustion ignition-improving additives.
Cetane index approximates fuel ignition quality through correlation with other fuel properties.
Since it is not affected by the use of combustion improver additives, cetane index estimates the
fuel’s base cetane number.
Lubricity
Lubricity describes the ability of a fluid to minimize friction between – and damage to – surfaces
in relative motion under loaded conditions. Diesel fuel injection equipment relies on the
lubricating properties of the fuel. Shortened life of engine components such as fuel injection
pumps and unit injectors usually can be attributed to a lack of fuel lubricity, which is a concern
for engine manufacturers. ASTM D975 does not adequately address this property.
Additional lubricity information can be found in the Society of Automotive Engineers (SAE)
Technical Papers 952372, “ISO Diesel Fuel Lubricity Round Robin Program” and 981363,
“Continued Evaluation of Diesel Fuel Lubricity by Pump Rig Tests.” SAE can be contact at
www.sae.org or (412) 776-4841.
47
Detergency
Some diesel fuels that do not contain detergents have a tendency to form carbon deposits on
certain fuel injectors. It has generally been found that low sulfur fuels and thermally unstable
fuels have a greater tendency to form these deposits. Detergent additives will prevent carbon
deposits, which interfere with fueling and fuel spray patterns, from forming.
Dirty injectors will invariably give rise to higher smoke levels in all equipment. It can limit
power by restricting flow in some equipment. Diesel fuel detergency is measured using the L10
Injector Deposit Test. Passing limits for the tests are shown in the attached table. These limits are
expressed in terms of a CRC rating for injector cleanliness and flow loss criterion.
Please refer to Cummins L10 Injector Depositing Test to Evaluate Diesel Fuel quality SAE Paper
for further support and explanation of the detergency issue.
Water and Sediment
Diesel fuel should be clear in appearance and free of water and sediment. The presence of these
materials generally indicates poor fuel handling practices. Water and sediment can shorten filter
life or plug fuel filters which can lead to engine fuel starvation. In addition water can promote
fuel corrosion and microbial growth. For that reason, we recommend separate analysis and
maximum levels.
The level of water specified in the attached table is within the solubility level of water in fuel and
does not represent free water.
ASTM D6217 is the preferred test method that covers the determination of the mass particulate
contamination in middle distillate fuels by filtration. However, since D6217 is a newer test that
might not be accessible to all, D2276 and D5452 are also included in the specification.
A quick field test for visually checking water and sediment is ASTM D4176. If free water or
sediment is observed, laboratory testing should be conducted to determine when the
recommendations specified in the attached table are being met.
Bacteria and Fungus
This represents an additional specification designed to minimize fuel contamination that has
resulted from the presence of free water in transport, storage or vehicle tanks. Microbes do not
live in fuel; they live in the interface that forms between the fuel and free water. The presence of
microbes can cause operational problems, corrosion, and sediment build-up in diesel fuel
systems. Note, however, the absence of microbes in fuel received at filling stations does not
ensure the absence of microbes in fuel storage tanks or vehicle fuel systems.
Accelerated Thermal Stability
Diesel fuel should be stable under normal storage and use conditions. Unstable fuel will darken
and form black particulate materials that will cloud fuels and create gum residues in the fuel
system. The accelerated thermal stability test is intended to predict the resistance of fuel to
degradation at normal engine operating temperature and to provide an indication of overall fuel
stability.
48
Distillation
This property provides a measure of the temperature range over which a fuel volatilizes or turns
to a vapor. Volatility is one of the primary factors that distinguish No. 1 fuel from No. 2 fuel. No.
1 diesel typically has greater volatility than No. 2. The highest temperature recorded during
distillation is called the end point. However, because it is difficult to measure and duplicate a
fuel’s end point, the fuel’s 90% to 95% distillation point is commonly used. The 95% distillation
is the preferred point since it is not difficult to repeat and because it is closer to the fuel’s end
point than the 90% point currently measured in D975. Additionally, reporting the 10%
distillation and 50% distillation points is recommended because they are part of the cetane index
calculation. Equipment in applications that operate at low loads and frequent idle periods should
benefit from a lower end point.
Sulfur
To assist diesel engine manufacturers in meeting mandated limits for particulate matter in diesel
engine exhaust; sulfur content is limited by U.S. federal law to 0.05% for diesel fuel used in onhighway applications.
Copper Corrosion
The copper strip corrosion test indicates potential compatibility problems with fuel system
components made of copper alloys such as brass or bronze. The limit requires that the fuel not
darken these parts under the test conditions.
Flash Point
The flash point temperature of diesel fuel is the minimum temperature at which the fuel will
ignite (flash) on application of an ignition source under specified conditions. Flash point varies
inversely with the fuel’s volatility. Flash point minimum temperatures are required for proper
safety and handling of diesel fuel. Due to its higher flash point temperature, diesel fuel is
inherently safer than many other fuels, such as gasoline.
Aromatics
This property is listed simply as a reminder that there are both federal and state limitations on
diesel fuel aromatics content.
Kinematic Viscosity
Viscosity affects injector lubrication and fuel atomization. Fuels with low viscosity may not
provide sufficient lubrication for the precision fit of fuel injection pumps or injector plungers,
which may result in leakage or increased wear. Fuels that do not meet viscosity requirements can
lead to performance complaints. Fuel atomization is also affected by fuel viscosity. Diesel fuels
with high viscosity tend to form larger droplets on injection that can cause poor combustion and
increased exhaust smoke.
Rams bottom Carbon Residue
The Rams bottom Carbon Residue test is intended to provide some indication of the extent of
carbon residue that result from the combustion of a fuel. The limit is a maximum percentage of
deposits by weight.
49
Ash Content
Ash is a measure of the amount of metals contained in the fuel. High concentrations of these
materials can cause injector tip plugging. Combustion deposits and injection system wear.
Soluble metallic materials cause deposits while abrasive solids will cause fuel injection
equipment wear and filter plugging.
EMA Consensus Position
JOINT EMA/TMC PUMP GRADE SPECIFICATION FOR PREMIUM DIESEL FUEL
PROPERTY
TEST METHOD
RECOMMENDED VALUE
API GRAVITY***
D287*
39 MAX.
BTU CONTENT***, GROSS
D2382
136,000 MIN.
o
CLOUD POINT, C
D2500
4o C BELOW 10th percentile
minimum ambient temperature
LTFT
D4539
4o C BELOW 10th percentile
minimum ambient temperature
CETANE INDEX
D4737
45 MIN.
CETANE NUMBER
D613
50 MIN.
LUBRICITY
D6078
3100g. MIN.
or
D6079
DETERGENCY
L10 - Injector
0.45mm dia. wear scar, max. @
60oC
CRC Rating </= 10
Deposit Test
% Flow Loss </= 6
WATER, PPM
D1744
200 MAX.
SEDIMENT, G/M3
D6217
10 MAX.
SEDIMENT, MG/L
D2276 or 5452
10 MAX.
BACTERIA & FUNGUS
**
0 cfu/ml
ACCELERATED THERMAL
STABILITY
OCTEL, F21
80% Reflectance
o
DISTILLATION, C:
10%
D86
or
or
or
REPORT
50%
REPORT
90%
332 MAX.
95%
355 MAX.
50
SULFUR, WT %
D2262
0.05 MAX. OR LEGAL
COPPER CORROSION
D130
3b MAX.
o
FLASH POINT, C***
D92
o
52oC MIN. OR LEGAL (38 C
for winter)
AROMATICS, VOL.%
D1319
LEGAL
VISCOSITY, [email protected] 100F
(40oC)***
D445
1.9 - 4.1 (1.7 for winter)
RAMSBOTTOM RESIDUE, %
D524
0.15 MAX.
ASH CONTENT, % WT.
D482
0.01 MAX
APPEARANCE
D4176
2 or less and no visible free water
or sediment
*Numbers preceded by a 'D' refer to ASTM Standards; ASTM, 100 Barr Harbor Drive, West
Conshohocken, PA 19428-2959
** Appropriate test procedures for bacteria and fungus are available from the American Society from
Microbiology (ASM), 1325 Massachusetts Ave. N.W., Washington D.C.
*** In Extreme cold climate conditions described by ASTM 10th percentile temperatures below -10C in
December, January, and February, the gravity, BTU, flash point and viscosity specification may be waved
and the flash point and viscosity may deviate to the indicated values to achieve the desired cold flow
Technical Statement on the Use of Biodiesel Fuel in Compression Ignition
Engines
Introduction
The Engine Manufacturers Association (EMA) is an international membership organization
representing the interests of manufacturers of internal combustion engines. In 1995, EMA
published a “Statement on the Use of Biodiesel Fuels for Mobile Applications.” Since that time,
there has been increased worldwide interest in reducing reliance on petroleum-based fuels and
improving air quality. This has led many stakeholders – including engine manufacturers – to
continue investing in alternative, renewable fuels – including biodiesel fuels – as a substitute for
conventional diesel fuel. In addition, recent government proposals in the United States and
Europe have called for incentives or mandates to increase the production and use of renewable
fuels.
The current statement, which takes into consideration additional laboratory and field research,
conducted since the publication of the 1995 statement, sets forth EMA’s position on the use of
biodiesel fuels with current engine technologies. It should be noted that only limited data are
available regarding the use of biodiesel with those technologies that have been, or are about to
be, introduced to meet the U.S. Environmental Protection Agency’s (EPA) 2004 heavy duty onhighway emission standards. Moreover, because of the absence of available data, the current
51
statement does not address the potential use of biodiesel fuels with advanced emission control
technologies, including after-treatment systems designed for future ultra-low emission engines.
Biodiesel
Biodiesel fuels are methyl or ethyl esters derived from a broad variety of renewable sources such
as vegetable oil, animal fat and cooking oil. Esters are oxygenated organic compounds that can
be used in compression ignition engines because some of their key properties are comparable to
diesel fuel. “Soy Methyl Ester” diesel (SME or SOME), which is derived from soybean oil, is the
most common biodiesel in the United States. “Rape Methyl Ester” diesel (RME) derived from
rapeseed oil, is the most common biodiesel fuel in Europe. Collectively, these fuels are
sometimes referred to as “Fatty Acid Methyl Esters” (FAME). A process called transesterfication
produces Biodiesel fuels. In transesterfication, in various oils (triglycerides) are converted into
methyl esters through a chemical reaction with methanol in the presence of a catalyst, such a
sodium or potassium hydroxide. The by-products of this chemical reaction are glycerol’s and
water, both of which are undesirable and need to be removed from the fuel along with traces of
methanol, unreacted triglycerides and catalyst, such as sodium or potassium hydroxide. Biodiesel
fuels naturally contain oxygen, which must be stabilized to avoid storage problems. Although
biodiesel feedstock does not inherently contain sulfur, sulfur may be present in biodiesel fuel
because of contamination during the transesterfication process and in storage.
Biodiesel Specifications
Biodiesel is produced in a pure form (100% biodiesel fuel, referred to as B100 or neat biodiesel)
and may be blended with petroleum-based diesel fuel. Such biodiesel blends are designated as
Bxx, where xx represents the percentage of pure biodiesel contained in the blend. Examples
include B5 and B20.
Several standard-setting organizations worldwide have recently adopted biodiesel specifications.
Specifically, ASTM International recently approved a specification for biodiesel referenced as
D6751. In addition, German authorities have issued a provisional specification for FAME under
DIN 51606. Europe’s Committee for Standardization (CEN) is in the final stages of setting a
technical standard for biofuels to be referred to as EN 14214.
The European specifications include more stringent limits for sulfur and water, as well as a test
for oxidation stability, which is absent from the current ASTM specification. Depending on the
biomass feedstock and the process used to produce the fuel, B100 fuels should meet the
requirements of either ASTM D6751 or an approved European specification, such as DIN 51606
or EN 14214 (once adopted). In addition, it should be noted that the National Biodiesel Board
has created the National Biodiesel Accreditation Commission to develop and implement a
voluntary program for the accreditation of producers and marketers of biodiesel. The
commission has developed a standard titled “BQ-9000, Quality Management System
Requirements for the Biodiesel Industry,” for use in the accreditation process.
52
Biodiesel Blends
Public and private bodies recently have taken positions regarding the use of biodiesel blends. For
example, the U.S. Energy Policy Act of 1992 (EPAct) was amended in 1998 to allow covered
fleets to use biodiesel to fulfill up to 50 percent of their annual alternative fuel vehicle (AFV)
acquisition requirements. Under EPAct’s Biodiesel Fuel Use Credits provisions, covered fleets
are allocated on biodiesel fuel use credit – the equivalent of a full vehicle credit – for each 450
gallons of B100 purchased and consumed. Such credits are awarded only if the blended fuel
contains at least 20 percent biodiesel (B20) and is used in new or existing vehicles weighing at
least 8,500 pounds. No credits are awarded for biodiesel used in vehicles already counted as an
AFV.
However, during the same period a consortium of diesel fuel injection equipment manufacturers
(FIE Manufacturers) issued a position statement concluding that blends greater than B5 can
cause reduced product service life and injection equipment failures. According to the FIE
Manufacturers’ Position Statement, even if the B100 used in a blend meets one or more
specifications, “the enhanced care and attention required to maintain the fuels in vehicle tanks
may make for a high risk of noncompliance to the standard during use.” As a result, the FIE
Manufacturers disclaim responsibility for any failures attributable to operating their products
with fuels for which the products were not designed. Based on current understanding of biodiesel
fuels and blending with petroleum based diesel fuel, EMA members expect that blends up to a
maximum of B5 should not cause engine or fuel system problems, provided the B100 used in the
blend meets the requirements of ASTM D6751, DIN 51606, or EN 14214. If blends exceeding
B5 are desired, vehicle owners and operators should consult their engine manufacturer regarding
the implications of using such fuel.
Engine Operation, Performance and Durability
The energy content of neat biodiesel fuel is about 11 percent lower than that of petroleum-based
diesel fuel on a per gallon basis, which results in a power loss in engine operation. The viscosity
range of biodiesel fuel is higher than that of petroleum-based diesel fuel (1.9 to 6.0 centistokes
versus 1.3 to 5.8 centistokes), which tends to reduce barrel/plunger leakage and thereby slightly
improve injector efficiency. The net effect of using B100 is a loss of approximately 5 percent to
7 percent in maximum power output. The actual percentage power loss will vary depending on
the percentage of biodiesel blended into the fuel.
Any adjustment to the engine in service to compensate for such power loss may result in a
violation of EPA’s anti-tampering provisions. To avoid such illegal tempering, as well as
potential engine problems that may occur if the engine is later operated with petroleum-based
diesel fuel, EMA recommends that users not make such adjustments. Neat biodiesel and higher
percentage biodiesel blends can cause a variety of engine performance problems, including filter
plugging, injector coking, piston ring sticking and breaking, elastomer seal swelling and
hardening/cracking, and severe engine lubricant degradation.
53
At low ambient temperatures, biodiesel is thicker than conventional diesel fuel, which would
limit its use in certain geographic areas. In addition, elastomer compatibility with seals, hoses,
gaskets, and wire coating should be monitored regularly. There is limited information about the
effect of neat biodiesel and biodiesel blends on engine durability during various environmental
conditions. More information is needed to assess the viability of using these fuels over the
mileage and operating periods typical of heavy-duty engines. See: “Diesel Fuel Injection
Equipment Manufacturers Common Position Statement on Fatty Acid Methyl Ester Fuels as a
Replacement or Extender for Diesel Fuels.” (May 1, 1998)
Emission Characteristics
In October 2002, the EPA released a draft report titled, “A Comprehensive Analysis of Biodiesel
Impacts on Exhaust Emissions.” The draft technical report can be found on the EPA website:
http://www.epa.gov/otag/models/biodsl.htm. Use of neat biodiesel and biodiesel blends in place
of petroleum-based diesel fuel may reduce visible smoke and particulate emissions, which are of
special concern in older diesel engines in non-attainment areas. In addition, B100 and biodiesel
blends can achieve some reduction in reactive hydrocarbons (HC) and carbon monoxide (CO)
emissions when used in an unmodified diesel engine. Those reductions are attributed to the
presence of oxygen in the fuel. Oxygen and other biodiesel characteristics, however, also
increase oxides of nitrogen (NOx) in an unmodified engine. As a result, B100 and biodiesel
blends produce higher NOx emissions than petroleum-based diesel fuel. As such, EMA does not
recommend the use of either B100 or biodiesel blends as a means to improve air quality in ozone
non-attainment areas.
Storage and Handling
Biodiesel fuels have shown poor oxidation stability, which can result in long-term storage
problems. When biodiesel fuels are used at low ambient temperatures filters may plug and the
fuel in the tank may thicken to the point where it will not flow sufficiently for proper engine
operation. Therefore, it may be prudent to store biodiesel fuel in a heated building or storage
tank, as well as heat the fuel systems’ fuel lines, filters, and tanks. Additives also may be needed
to improve storage conditions and allow for the use of biodiesel fuel in a wider range of ambient
temperatures.
To demonstrate their stability under normal storage and use conditions, biodiesel fuels tested
using ASTM D6468 should have a minimum of 80 percent reflectance after aging for 180
minutes at a temperature of 150° C. The test is intended to predict the resistance of fuel to
degradation at normal engine operating temperatures and provides an indication of overall fuel
stability. Biodiesel fuel is an excellent medium for microbial growth. Inasmuch as water
accelerates microbial growth and is naturally more prevalent in biodiesel fuels than in petroleumbased diesel fuels, care must be taken to remove water from fuel tanks. The effectiveness of
using conventional anti-microbial additives in biodiesel is unknown. The presence of microbes
may cause operational problems, fuel system corrosion, premature filter plugging, and sediment
build-up in fuel systems.
54
Health and Safety
Pure biodiesel fuels have been tested and found to be nontoxic in animal studies. Emissions from
engines using biodiesel fuel have undergone health effects testing in accordance with EPA Tier
II requirements for fuel and fuel additive registration. Tier II test results indicate no biologically
significant short-term effects on the animals studied other than mirror affects on lung tissue at
high exposure levels. Biodiesel fuels are biodegradable, which may promote their use in
applications where biodegradability is desired – for example, marine or farm applications.
Biodiesel is as safe in handling and storage as petroleum-based diesel fuel.
Warranties
Engine manufacturers are legally required to provide an emissions warranty on their products –
which are certified to EPA’s diesel fuel specification. They also typically provide commercial
warranties. Individual engine manufacturers determine what implications the use of biodiesel
fuel has on the manufacturers’ commercial warranties. It is unclear what implications the use of
biodiesel fuel has on emissions warranty, in-use liability, anti-tampering provisions and the like.
As noted above, more information is needed about the impact of long-term use of biodiesel on
engine operations.
Economics
The cost of biodiesel fuels varies depending on the base stock, geographic area, variability in
crop production from season to season, and other factors. Although the cost may be reduced if
relatively inexpensive feedstock – such as waste oils or rendered animal fat – is used instead of
soybean, corn or other plant oil, the average cost of biodiesel fuel nevertheless exceeds that of
petroleum-based diesel fuel. That said, users considering conversion to an alternative fuel should
recognize that the relative cost of converting an existing fleet to biodiesel blends is much lower
than the cost of converting to any other alternative fuel because no major engine, vehicle, or
dispensing system changes are required.
EMA Conclusions
Depending on the biomass feedstock and the process used to produce the fuel, B100 fuels should
meet the requirements of either latest revisions of ASTM D6751 or an approved European
specification.
Biodiesel blends up to a maximum of B5 should not cause engine or fuel system problems,
provided the B100 used in the blend meets the latest revisions of ASTM D6751 which as of this
publication release is ASTM D 6751-07a, DIN 51606, or EN 14214. Most engine manufactures
approve up to a B5 blend and possibly higher blends, engine manufacturers should be consulted
when transitioning to biodiesel.
55
Biodiesel blends may require additives to improve storage stability and allow use in a wide range
of temperatures. In addition, the conditions of seals, hoses, gaskets, wire coating, dispenser and
vehicle fuel filters should be monitored regularly when biodiesel fuels are used
Although the actual loss will vary depending on the percentage of biodiesel blended in the fuel,
the net effect of using B100 fuel is the loss of approximately 5 percent to 7 percent in maximum
power output.
Historically B100 and biodiesel blends have reduced PM, HC and CO emissions and increase
NOx compared with petroleum-based diesel fuel used in an unmodified diesel engine. However
through more recent testing by National Renewable Energy Laboratory results show that NOx
emissions are neutralized by utilizing B100 or biodiesel blends. Conversely NOx is reduced in
heating oil applications consistent with the blend of biodiesel being used.
Biodiesel fuels have generally been found to be nontoxic and are biodegradable, which may
promote their use in applications where biodegradability is desired.
Individual engine manufacturers determine what implications the use of biodiesel fuel has on the
manufacturers’ commercial warranties.
Although several factors affect the cost of biodiesel fuel, its average cost may exceed that of
petroleum-based diesel fuel. However, the relative cost of converting an existing fleet to
biodiesel blends is much lower than the cost of converting to other alternative fuels.
56
Appendix 3: Biodiesel Quality Assurance Program for the Fleet25
How to Buy Fuel
When purchasing bulk fuels, ask for the fuel specifications. Verify that the fuel properties are
suitable for the intended use. If you are buying diesel fuel in the winter you should know what
the documented cold weather characteristics are so that you can prepare accordingly for local
climate conditions. Problem free fuel performance begins by demanding ASTM benchmarked
fuels. Once you have obtained a quality fuel you must keep the fuel “on-spec.” In other words, at
the same ASTM quality as you originally received it. Ensuring that your fuel storage tanks are
free of contamination, (most notably, free of water) is a positive step in preserving the quality
specifications of the fuel which you have purchased.
An additional way to guarantee that you are starting with quality product is to obtain your
biodiesel from BQ-9000 accredited producers or certified fuel marketers. Look for this symbol of
quality. It is always an excellent idea to execute a simple field inspection of incoming fuel for
cleanliness and haze which could indicate the presence of water or wax (in cold weather).
Suspended water in fuel may result in water in all stages of fuel distribution system. Inspect
regularly with all bulk quantities of fuel before accepting it for delivery. The purpose of this
visual inspection is to prevent accepting fuel that may be currently impaired with contaminants
and water. It is highly recommended that fleet managers regardless of the equipment secure a
copy of the Fuel Quality and Performance Guide which contains step by step instructions
covering fuel procurement, acquisition, storage and usage to begin to build a proactive fuel
management program for his/her independent operation.
25
Fuel Quality and Performance Guide, A troubleshooting checklist for diesel fuel,
biodiesel and Bioheat users. Publication is sponsored by the United States Soybean Council and
the Soybean Check off program, 2006, available through the National Biodiesel Board.
57
Figure 5: Example of Distillate Fuel Haze Rating Standard Using ASTM Clear and Bright
Test
Pass, Pass, Fail, Fail, Fail, Fail
Fleet Fuel Purchasing Checklist
A great deal of information pertaining to biodiesel, diesel fuel and heating oil issues have been
addressed throughout this comprehensive publication on fuel quality. In the end a professional
fleet manager must assume responsibility to provide a clean storage tank to ensure a positive user
experience with the fuel which you purchase.
Pre-Buy Considerations
1. Secure a reliable and trustworthy fuel distributor who takes time to discuss his/her
company credentials and how they will benefit your operations.
2. Request that delivery personnel present at time of off-loading copies of BOL, (bill of
lading) detailing type of fuel and quantity as well COA, (certificate of analysis)
representing that the fuel is meeting ASTM specifications, (D6751, D975, D396 or
specific blends of each).
3. When executing your supply agreement make sure that delivery personnel stick your
storage vessel before and after the drop noting water accumulation on the delivery slip.
4. Regardless if you are purchasing biodiesel blended diesel fuel or generic diesel fuel
specify during your negations what specific cold weather parameter you will require
during the winter season. Be specific; if you wish to operate at -20F in January and
February make sure that your supplier is capable of optimizing your blend to eliminate
the guess work of your actual operability point. If you remember to specify your fuels
cold flow values you will not need to labor over the type of feedstock that your
distributor is accessing (biodiesel) to blend with your generic fuel, (remember the
feedstock variables discussed on page 23.
58
Post-Buy Considerations
1. Have a company employee stick the storage vessel prior to the delivery and
immediately following to confirm sticking values generated by truck delivery
personnel, compare results with driver noting any discrepancies.
2. Retrieve (2) quart container running samples off the truck prior to off-loading into the
storage vessel. Keep them available for possible analysis should fuel quality issues
arise. Hold samples through the second re-supply of the tank. In the event testing is
required offer your fuel supplier a sample of the retains so that they may round robin
(exact tests) to eliminate technician error.
3. If any accumulated water is recognized remove it immediately, bulk storage, saddle
tanks and water fuel separators.
4. Keep a log book of all inbound shipments as well water accumulation where
appropriate.
Following these simple steps prior to and immediately following receipt of your fuel deliveries
will ensure that you will reduce unscheduled vehicle downtime
59
Appendix 4: ASTM D 6751-07a
Biodiesel (B100)
Property
ASTM Method
Limits
Units
Flash Point
D93
130.0 min.
Degrees C
Water and Sediment
D2709
0.050 max
% vol.
KinematicViscosity,40C
D445
1.9 - 6.0
Sulfated Ash
D874
0.020 max.
% mass
Sulfur (S 15 grade)
D5453
0.0015 max.
ppm
Sulfur (S 500 grade)
D5453
0.05 max.
ppm
Copper Strip Corrosion
D130
No. 3 max.
Cetane
D613
47 min.
Cloud Point
D2500
Report Customer
*Carbon Residue
D4530*
0.050 max.
% mass
Acid Number
D664
0.50 max.
mg KOH/gm
Free Glycerin
D6584
0.020 max.
% mass
Total Glycerin
D6584
0.240 max.
% mass
Phosphorus Content
D4951
10 max
ppm
Distillation Temperature,
Atmospheric Equivalent
Temperature,
90% Recovered
D1160
360 max
Degrees C
Combined Na/K
EN 14538
5 ppm
ppm
Combined Ca/Mg
EN 14538
Oxidation Stability
EN 14112
5 ppm
3 min
ppm
hours
*Workmanship
See below
mm2/sec.
Degrees C
*Carbon residue, 100% of sample
*Workmanship, free of undissolved water, sediment & suspended matter
Bold criteria = BQ-9000 “Critical Specification Testing once production process under control.
60
Appendix 5: ASTM D 396
Heating Oil
Property
ASTM Method
Limits
Flash Point
D93
38 min.
Degrees C
Water and Sediment
D2709
0.050 max
% vol.
KinematicViscosity,40C
D445
1.9 - 3.4
mm2/sec.
Ash
D482
----------------------
% mass
Sulfur (Grade No.2)
D129
0.50 max.
% mass
Sulfur (Grade No. 2- Low
Sulfur)
D2622
0.05 max.
% mass
D130
No. 3 max.
D613
---------------------
Degrees C
D97
-6
Degrees C
D2500
---------------------
% mass
D4539/D6371
---------------------
D1298
876
kg/m3
D524
0.35 max.
mg KOH/gm
D 976
---------------------
D1319
---------------------
% vol.
D86
282-338
Degrees C
Copper Strip Corrosion
Cetane
Pour Point
Cloud Point
Units
or
LTFT/CFPP
Density, 15C
Ramsbottom Carbon
Residue
Cetane Index
or
Aromaticity
Distillation Temperature,
90% Recovered
61
Appendix 6: Addressing Fuel Quality Deficiencies with Additives26
Many of the additives available for use in the middle distillates have the ability to affect either
directly or indirectly, fuel properties and emission requirements of diesel engines
The various additives, their use, and their effects will be addressed in the following sections.
Cetane improvers are almost universally alkyl nitrates. They are used in variable concentrations
based on the starting cetane value of the fuel being treated. Historically, the lower the cetane
value the more challenging and expensive it will be to obtain desirable goals. For example,
elevating a 40 rating to a 50 rating will be more costly than transitioning from 45 rating to a
rating of 50. Up to a certain rating level, around 45 to 50, increasing the cetane number generally
will improve starting, reduce smoke, noise, HC and CO emissions, and improve fuel economy.
The cetane number is measured using a cetane engine but estimates on cetane index are often
used in the absence of an engine. Cetane index is based on physical properties and does not
respond to cetane improver, which is its major disadvantage. It is also important that increasing
the cetane value does not become an obsession because cetane values that are too high will cause
thermal stability problems with the same fuel. This is an instance of more not being better.
Stability improvers have historically been nitrogen-based organic compounds that retard the
oxidation and polymerization processes involving pyrrole and sulfur containing materials in both
diesel fuel and heating oil. With the introduction of low sulfur diesel fuel in 1993, the hydro
treating used to reduce sulfur has improved diesel fuel stability relative to color and sediment
formation. However, some severely hydro treated fuels and the soon to arrive ultra low sulfur
diesel fuel >15 ppm may tend to form peroxides during storage. That in turn requires some of
these key additive compounds to maintain expected performance specifications. Stability
improvers directly affect distillate performance by controlling formation of gums and
insoluble’s, which can block fuel filters and nozzles. That can cause restricted fuel flow and
distorted spray patterns both in fuel injectors and burner nozzles. ASTM D2274 is currently used
to determine oxidation stability to meet some diesel fuel specifications. Most often the ASTM D
6468 test method is used. This test predicts storage stability as does D2274, but also predicts
thermal stability and is popular in the United States because it is quick. Thermal stability is
important because of increasing hot fuel recirculation temperatures. Other lower temperature,
one-term tests are also used to assess storage stability in laboratory evaluations such as the OctelStarreon F31-81 test.
Biocides are used to deter growth of microorganisms in diesel fuel storage tanks, particularly in
the water bottoms and on the vessel walls. These microorganisms can plug fuel lines on filters,
stabilize emulsions and accelerate both gum formation and corrosion. Filter plugging is the first
phenomenon observed but by the time that occurs, the other problems of emulsions, gum and
corrosions may already be in advanced stages. Because of their relatively high cost and the
concern of microbes developing immunity, biocides are not used on a continuous basis. They are
most often only added on an as-needed basis, but are sometimes added quarterly or seasonally.
Biocides are regulated because many of them are used in applications involving human contact.
26
Innospec Fuel Specialties, Littleton, Colorado, 2006
62
If used properly, biocides are effective in controlling biological growth and the problems they
introduce. An adjunct to their use is good housekeeping, including minimizing tank water
bottoms.
Corrosion inhibitors provide protection to the entire system that comes into contact with the
treated diesel fuel or heating oil. This includes refinery storage facilities, transportation vessels
including pipelines, terminal storage tanks and end use vehicles. The inhibitor follows the fuel
since all modern corrosion inhibitors are fuel soluble. Most inhibitors are based on some type of
dimmer acid and, as such, are susceptible to salt formation and loss by extraction when contacted
by caustic water carried over from the cracked stock treatment system. Good housekeeping is
essential. By inhibiting corrosion, the chance of filter plugging by corrosion products is
minimized and, of even greater value, the life of storage tanks and pipelines is substantially
extended. As will be discussed later, corrosion inhibitors can also provide lubricity benefits by a
mechanism similar to that which is responsible for corrosion inhibition.
Metal Deactivator is an additive of universal application in the petroleum industry. It is of value
in all stocks from gasoline to lube oil, and from diesel fuel to home heating oil. It provides color
and oxidation stability in diesel fuel. Its primary value is in chelating copper ions and preventing
them from catalyzing gum forming oxidation reaction, which is abundant in heating oil. Pound
for pound it is the most valuable additive for finishing petroleum products. As little as 1 mg/L
can protect against copper ion contamination and boost the efficacy of antioxidants in the fuel.
Cold Flow Improvers are used seasonally to allow maximum performance in cold climates.
They are the additives with the highest visibility in that their absence or failure to function will
cause operational shutdown. The action of cold flow improver is to lower the operability
temperature to either the pour point or cold filter plugging point. This is accomplished by
interfering with or modifying the growth of wax crystals, which can pass through fuel filters.
In their absence, large wax crystals form which entrap the liquid fuel and creating non-filterable
gel. Nearly all cold-flow improvers are based on ethylene/vinyl acetate copolymers known as
EVAs. However, there are many variations involving other co-monomers in the chain or the use
of anti-settling or anti-flocculation co-additives or the use of heavy wax modifiers. The
combination of this unique cold flow system is quite formidable and capable of kerosene
blending.
Treat level ranges are determined by region and temperature values as well as on how waxy the
fuel is and the lowest operating temperature required. The most basic performance tests are pour
point and cloud point, which represent the severity extremes. Many prefer the cold filter
plugging point (CFPP, IP309) or the lowest temperature filterability test (LTFT, ASTM D4539)
which are intermediate in severity between pour point and cloud point and also seem to correlate
better with vehicle operating temperature requirements.
Anti-Haze Additives are sometimes added to diesel fuel packages to control possible water haze
problems created by the addition of detergent. In other cases, the refiner may require the antihaze or additive package to improve haze performance beyond that of untreated fuel. There is
occasionally a request for spot treatment to settle water in a storage tank.
63
Anti-haze additive promotes rapid and clean separation of water dispersed in your middle
distillates. In addition, it can minimize the thickness of any emulsion, which may form at the
fuel/water bottom interface. This in turn allows the maximum amount of clear fuel to be pumped
and also allows water bottoms to be drawn off without putting hydrocarbons in the water treating
system.
Smoke Suppressants are categorized as combustion improvers. Smoke consists mainly of
carbon particles or agglomerates plus associated condensed fuel. Smoke suppressants are organ
metallic compounds generally of manganese, iron and barium. Barium used to be the most
popular but is losing ground because of toxicity concerns. However, few if any of these products
are currently used in the United States because of government registration limitations and
because their use may actually increase particulate matter weight.
Cetane improver is also a type of combustion improver. Cetane improvers work by decomposing
during combustion to produce free radicals, thereby enhancing the chain initiation rate of the
diesel fuel and improving ignition characteristic. More recently, interest has focused on
combustion improvers composed of a compound of copper, manganese or alkaline earth metals.
These improvers are intended to catalyze the combustion process by reducing the ignition
temperatures. This would result in more complete combustion and, consequently, reduce
emission levels. These types of additives could become increasingly important if particulate traps
are employed where they would catalyze the combustion of deposited carbon to promote filter or
trap regeneration. Products of this nature commonly have an increased cost in the range of .035
cents to .040 cents per gallon above conventional distillates.
Detergents for middle distillates are currently one of the more high profile additives used in the
United States. Many markets are using detergent treatments to create a premium diesel fuel and
home heating oil although the definition of premium diesel fuel is still the subject of much
debate. Detergents are nitrogen based organic compounds, typically amines, amides or
succinimides. They are used in varying percentages depending on the demands created by market
drivers.
An effective detergent used at the correct concentration not only keeps injectors and oil burning
nozzles clean but also can remove pre-formed deposits. By maintaining a clean injection system
the diesel engine and oil burner will maintain lower emissions and continue to operate at peak
efficiency. The distinction between keep – clean and clean – up is a gradual one. The detergent
concentration therefore provides the basis for effective maintenance or improvement in
emissions and economy in diesel powered engines.
Conductivity Improvers are different than the other additives under discussion in that they do
not provide a fuel quality or engine performance benefit. These additives provide for electrostatic
safety in the use and handling of diesel fuel and/or heating oil. When fuels are pumped or
filtered, they develop a charge, which must be able to migrate through the bulk fuel to container
wall, and that accumulated charge will cause a spark in the vapor space. If the vapor space has an
explosive ration of air and fuel vapor, then an explosion can occur.
64
For that reason, it is important to provide a path for charge to migrate through the fuel by adding
to the conductivity improver. Since conductivity increases proportionately with temperatures, use
concentrations recommended by the fuel additive supplier. Grounding all vessels and transfer
lines must be carefully maintained and safe-pumping procedures must also be followed.
Dyes are currently used in the United States to differentiate between on-highway diesel fuel,
which is subject to a highway tax, and off-road and heating fuel, which are not taxed. There is
very little difference between the two fuels, the main difference being that there is, of course, no
cetane number specification on heating oil.
They can therefore be used interchangeably and dye is added to protect the tax revenue for the
government. The most effective application of dye is to add it with the least costly fuel since
blending of the cheaper fuel into the more expensive fuel would be most noticeable if the
cheaper fuel is the one that is dyed.
In this case, when the heating oil or off-road diesel fuel is dyed in the United States the Internal
Revenue Service stipulates the solvent Red 164 must be used at a strength equivalent to 11.1
mg/L of solvent. This a solid reference dye but nearly all refiners in the United States have
converted to liquid dyes for ease of handling and to eliminate dusting exposure. Liquid dyes are
available that are equivalent in shade but an up-treat is necessary to accommodate the strength
difference between solid and liquid dyes. Like middle distillates, any biodiesel being blended
into diesel fuel for off-road use must also be dyed in accordance with the information provided.
Deicers are used in diesel fuel in cold climates and low temperature seasons to prevent water that
settles out of the diesel fuel from freezing. Diesel fuel leaves the refinery saturated with water,
which could be up to 150 mg/L depending on the temperature and aromatic content of the diesel
fuel. As the fuel cools, some of the dissolved water drops out of the solution. If it is allowed to
freeze it could plug fuel line filters and starve the engine for fuel.
To prevent these water bottoms from freezing, refiners or marketers can elect to use a deicer or
actually an anti-icer. Glycol ethers are quite effective and can be used to safely address moisture
concerns.
Lubricity Additives have been used successfully for
many years in jet fuel to solve fuel pump wear
problems. Initially, the U.S. Military criterion was to
require 50% more than the minimum necessary to
control corrosion. More recently, lubricity tests have
received some levels of general recognition and the jet
fuel requirements are now also based on performance in
the ball-on-cylinder lubricity evaluator (BOCLE). Tests
have been developed that are being used in the industry
such as scuffing load BOCLE and the high frequency
reciprocating rig (HFRR).
65
At time of publication the chosen lubricity test chosen by by ASTM is the HFRR, ASTM D
6079. ASTM D 975 includes a <520 wear scar and is required for custody exchange no matter
whether low sulfur diesel or ultra low sulfur diesel. The Engine Manufacturers of America
require <460 wear scar under the D 6079 test standard
Sulfur compounds in diesel fuel convert to sulfate when combusted and these represent a major
contribution to particulate matter. When hydro treating to reduce sulfur, the naturally occurring
lubricity component in diesel is destroyed. Some acidic corrosion inhibitors have proven
effective in providing lubricity and are widely used today to provide both features. In some
cases, ester type additives have been adopted to address real and perceived needs for increased
concentration of lubricity improver.
Anti Foaming additives are added to diesel fuel to prevent or reduce foaming especially during
fueling. There are two principal advantages to the use of anti-foam: 1) The user will not get
diesel fuel on their hands if foam is prevented from coming up and out of the filter nozzle; and 2)
By preventing this foam-up, more fuel can be put into the tank at each fill up.
It is in the refiner’s interest to take advantage of these benefits. Anti-foams are widely used in
Europe. Diesel fuels are less viscous and lower boiling in the United States. Both those qualities
tend to reduce foaming tendencies. This reduced tendency to foam, along with the fact that
truckers use most diesel fuel in the United States, makes de-foaming less necessary. As a result,
anti-foams are rarely used in the United States.
Summary of General Distillate Fuel Additives 27
Cetane Improvers
•
•
•
•
•
Easier starting
Reduced smoke
Less noise
Reduce HC (Hydrocarbons) and CO (Carbon Monoxides) and NOx
Improve fuel economy
Stability Improvers
•
•
•
•
Historically nitrogen-based organics
Best to add to cracked components
Stability measured by ASTM D2274 and ASTM D 6468 method and F31 for home
heating oil
Reduces unscheduled service calls in home heating oil market segment
Biocides
•
•
•
27
Usually nitromorpholines, triazines or boranes
Used to control growth of microorganisms
Decreases filter plugging, gum formation, and emulsions
Innospec Fuel Specialties, Littleton, Colorado, 2007
66
•
•
Used when needed or routinely but not continuously
Not a substitute for good housekeeping and minimizing water bottom
Corrosion Inhibitors
•
•
•
Most inhibitors are dimmer acids, transitioning to ester based
By controlling corrosion, filter plugging is reduced and tank and pipeline life are
extended
Performance evaluated by NACE TM 0172 or ASTM D665
Metal Deactivator
•
•
•
•
•
•
Pound for pound the most versatile additive available
Based on salicyladehyde and diaminopropane
Use concentration range 1-6 mg/L
Chelates ionic copper and other metals
Provides color protection and retards gum formation
Also extends antioxidant effectiveness
Cold Flow Improvers
•
•
•
•
•
Used seasonally to provide cold weather flow
Functions by interfering with wax crystal growth
Typical composition is ethylene vinyl acetate copolymer
Use level depends on wax content and temperature
Tests used are pour point, cloud point, cold filter plugging point and low temperature
filterability test
Anti-Haze Additives
•
•
Used to aid separation of fuel from water bottom
Difficult to predict field result from lab test
Smoke Suppressants
•
•
•
•
•
•
•
Smoke is mostly carbon particles plus condensed fuel
Suppressants work by inhibiting cracking reactions
Composition is generally based on metal salt
Cetane improver is another type of combustion improver designed to reduce emissions
More recent combustion improvers designed to reduce emissions
Intended to catalyze combustion process
May also promote filter or trap regeneration
Detergents/Dispersants
•
•
•
Adopted in United States to create premium diesel and now premium heating oil
Joint ASTM/NCWM committee created premium definition
Clean injectors help maintain low emissions and good fuel economy
67
Conductivity Improvers
•
•
•
•
•
Reduces electrostatic charge accumulation
Reduces incidents of spark discharge
Use concentration 1 mg/L to 2 mg/L in moderate climates
Cold temperature may require up to 5 mg/L
Goal is to provide minimum 50 pS/m conductivity
Dyes
•
•
•
•
Used to differentiate fuels from one another, taxable or not
Preferable to add to less expensive fuel
Most dyes are azo compounds but some are anthraquinones
Treat leave range from 5 mg/L up to 25 mg/L for gasoline and up to 25 mg/L for diesel
Deicers
•
•
•
•
Used to prevent freezing of separated water
Prevents fuel line and filter plugging
Composition is generally glycol ether
Used concentration is about 50 mg/L
Lubricity Additives
•
•
•
•
Used to control wear in fuel delivery systems
More critical issues with low sulfur fuels
Hydro treating reduces sulfur and natural lubricants
A must in <15 ppm Ultra Low Sulfur Fuel
Anti-Foam Additive
•
•
•
•
Used to prevent foam during refueling
Maximizes fuel drops, eliminates run outs, decreases delivery costs
Foam-up prevents topping off tank
Not widely used in the United States
68
Appendix 7: Diesel Fuel Properties – for #2 LSD/ULSD
D 975 – 06b vs. EMA FQP-1A
ASTM
Method
ASTM D975
Specifications
EMA Guidelines
FQP-1A
Flash Point
D93
≥ 52ºC [≥ 125.6ºF]
Appearance
D4176
-
Water & Sediment
Water ppm
D2709
D1744
≤ 0.05% vol.
-
≥ 52ºC [≥ 125.6ºF]
<2 & no visible free
water or sediment
≤ 0.05% vol.
200 max
D6217 or
D2276 or
D5452
-
10 max
Property
Sediment G/M3 max
Distillation
90% vol. recovered
minimum temp.
90% vol. recovered
maximum temp.
95% vol. recovered
maximum temp.
Kinematic Viscosity @
40ºC
Ash
D86
-
NCWM Premium Diesel
Definition
Recommendations
-
≤ 300ºC [572ºF]
D86
≤ 356ºC [672ºF]
≤ 332ºC [≤629ºF]
-
D86
-
≤ 355ºC [≤675ºF]
-
D445
1.9 – 4.1 cSt
D482
D2662,
D4294
D5453
≤ 0.01% mass
1.9 – 4.1 cSt
(1.7 for winter)
≤ 0.01% mass
≤ 0.05 % mass
≤ 0.05 % mass or legal
-
≤ 0.0015 % mass
-
-
D130
≤3
≤ 3b
-
D613
≥ 40
≥ 50
≥ 47
D4737
≥ 40
≥ 45
(or does not apply)
-
Aromatics
D1319
≤ 35 % vol.
Legal
-
Low Temperature
Operability by Cloud
Point, LTFT, or CFPP
D2500
D5733
D4539
D6371
Recommend meeting
ASTM D975 10th percentile
minimum ambient air
temperature
Seasonal – 4oC below
10th percentile minimum
ambient air temperature
Seasonal meet the ASTM
D 975 10th percentile
minimum ambient air
temperature by D 2500 or
D 4539
Ramsbottom Carbon
Residue on 10% Bottoms
D524
≤ 0.35% mass max
≤ 0.15% mass max
-
-
39.0 max
-
-
136,000 min
≤10.0 Rating
≤ 6.0% Flow Loss
-
D6468
Octel F21-61
-
-
≥ 80% reflectance @ 180
minutes
D6079
≤ 520 microns
≤ 450 microns
≤ 520 microns
Sulfur
Ultra Low Sulfur Diesel
Copper strip corrosion
rating
Cetane Number
OR - Calculated Cetane
Index
[may be used in lieu of
cetane number]
D4052
D 287
D2382
API Gravity
Energy Content
Detergency, L10-IDT
Rating
Cummins
Accelerated Stability
Lubricity
HFRR
-
69
-
U.S. Ultra Low Sulfur Diesel Fuel Properties
Engine manufacturers support the introduction and use of ultra low sulfur diesel fuel (i.e. fuel
<15 ppm sulfur using ASTM D2622). The U.S. Environmental Protection Agency has adopted
regulations establishing requirements for the introduction of ULSD. Meanwhile, many refiners
are introducing ULSD fuel earlier than required and states, other jurisdictions, and users are
considering incentive programs for its early introduction. In all such cases, engine manufacturers
support uniform and consistent properties for ULSD fuel. In order to facilitate such uniformity,
the Engine Manufacturers Association recommends that at a minimum all diesel fuel, including
ULSD fuel, meet the requirements of ASTM D975 as well as the following additional
performance requirements:
Cetane
Using ASTM D613, ULSD fuel should have a minimum cetane number of 40. Alternatively, to
ensure a minimum cetane number of 40, ULSD should have a minimum cetane index of 42.5
using ASTM D4737-96a.
Lubricity
Using the SL BOCLE test method (ASTM D6078), ULSD fuel should demonstrate minimum
lubricity of 3100 grams. Using the HFRR test method (ASTM D6079), the maximum lubricity of
ULSD should be 450 micrometers at a temperature of 60° C.
Thermal Stability
Using ASTM D6468, ULSD fuel should have a minimum of 70 percent reflectance after aging
for 180 minutes at a temperature of 150° C. Finally, in considering ULSD fuel properties, it is
also important to recognize the need to maintain the cleanliness of ULSD from the time it leaves
the refinery until it is delivered to the vehicle. Use of a filter smaller than five (5) microns at the
point where the fuel is dispensed into the vehicle helps to assure the needed cleanliness.
70
Appendix 8: Information Resource Websites
National Biodiesel Board
www.biodiesel.org
800-841-5849
•
BQ-9000 Accreditation Commission
www.bq-9000.org
573-635-3893
•
Steel Tank Institute
www.steeltank.com
•
U.S. Environmental Protection Agency (EPA)
www.epa.gov
•
Petroleum Equipment Institute
www.pei.org
•
Thomas Register
(To search for local labs in your area or testing equipment companies)
www.thomasnet.com
•
Biodiesel Magazine Industry Directory
www.biodieselmagazine.com
www.biodieselindustrydirectory.com
•
National Renewable Energy Laboratory (NREL)
2004 Biodiesel Handling & User Guidelines
http://www.nrel.gov/vehiclesandfuels/npbf/pdfs/tp31892.pdf
ASTM International Standards Worldwide, www.astm.org
Energy Information Agency, www.eia.doe.gov
71
Appendix 9: Engine Manufacturers’ Biodiesel Statements
Manufacturer
Case IH
Caterpillar
Cummins
Detroit Diesel
Fairbanks
Morse
Ford Motor
Company
General Motors
Honda
International
Isuzu
John Deere
Kubota
Mack
Mercedes-Benz
New Holland
UD
Trucks/Nissan
Diesel
Volkswagen
Volvo
Biodiesel Information
http://www.caseih.com/highlights/highlights.aspx?navid=121&recor
did=193&RL=ENNA
http://www.cat.com/cda/components/fullArticle?m=37675&x=7&id=
149474
http://www.everytime.cummins.com/every/news/release99.jsp
http://www.biodiesel.org/pdf_files/OEM%20Statements/2005_DDC
_Statement.pdf
http://www.fairbanksmorse.com/file_system/fairbanksmorseengineap
proves100biodiesel_copy_1.pdf
https://www.fleet.ford.com/showroom/environmental_vehicles/biodi
esel_vehicles.asp
http://www.gm.com/explore/fuel_economy/altfuel/index.jsp
http://corporate.honda.com/images/banners/environment/Honda_200
7_North_American_Environmental_Report.pdf
http://www.biodiesel.org/pdf_files/OEM%20Statements/2005_May_
OEM_International.pdf
http://www.isuzucv.com/faqs/AlternativeFuel2004081110.html
http://www.deere.com/en_US/rg/infocenter/infoevents/pr/2007/biodi
esel.html
http://www.biodiesel.org/pdf_files/OEM%20Statements/2006_OEM
_kubota.pdf
http://www.biodiesel.org/pdf_files/OEM%20Statements/2007_OEM
_MACK.pdf
http://www.mbusa.com/campaigns/alternative-fuels/index.do
http://www.newhollandmediakit.com/index.cfm?fuseaction=newsrel
eases.DisplayNewsReleases&NewsID=166
http://www.biodiesel.org/pdf_files/OEM%20Statements/2006_Nissa
n.pdf
http://www.biodiesel.org/pdf_files/OEM%20Statements/2005_OEM
_VW%20US%20Biodiesel_Statement_5_16_05.pdf
http://www.biodiesel.org/pdf_files/OEM%20Statements/2005_Volvo
_Truck_Corporation.pdf
72
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