White Paper- MACT Compliance for FRP Open Molding Operations

MACT Compliance for FRP Open Molding Operations
Using Binks LEL Technology – an Overview
Bradley P. Walter
Industrial Finishing
Abstract
Fiber
Reinforced
Plastic
(FRP,
GRP)
manufacturers in the United States must
comply with EPA MACT guidelines and provide
proof of emissions reduction in their
manufacturing
processes.
To
help
manufacturers
meet
stringent
styrene
emissions requirements
Industrial Finishing
has developed a series of non-atomizing resin
application guns for the open molding process.
The technology utilizes impinging fluid streams
to generate a flat fan-shaped pattern of large
resin droplets, greatly reducing the styrene (or
other monomer) emissions generated by the
application of resin to the mold surface.
Emissions testing was performed in December
2009 by
Industrial Finishing to verify the
non-atomizing performance of the Binks
Century LEL series FRP guns. This report
summarizes the design, proper selection and
use, and emissions test results of non-atomizing
resin and gel coat application technology
manufactured by
Industrial Finishing.
only recently has been applied to the
application of gel coats and laminating resins.
The basic operating principle of impingement
technology is to orient two or more continuous
jets of fluid at each other to generate a
diverging flat fan of fluid whereby the breakup
of the fan into large droplets is delayed as long
as possible. The large droplets eventually
created have a much smaller surface area to
volume ratio (SA:V) than small droplets,
resulting in a lower styrene evaporation rate
than a spray with the same volumetric flow rate
but a larger number of smaller droplets.
Binks LEL technology is a combination
of FRP spray guns, spray tips, air nozzles and
mixing valves that provide non-atomizing
application of resins and gel coats for open
molding processes. LEL is an acronym for "Low
Emission Laminator", but low emissions are not
the only benefit of LEL technology. Other
benefits of LEL technology include:
o
Introduction
Any composites manufacturer in the United
States that has the potential to emit 10 or more
tons of Hazardous Air Pollutant (HAP) is subject
to the EPA 40 CFR part 63 requirements to meet
HAP emissions standards for their composites
production processes.
To meet the new
standards, manufacturers must apply Maximum
Achievable Control Technology (MACT) to their
processes. One such available technology is
called non-atomizing resin application (NARA).
Impingement technology is a NARA method
that has been documented for many years1 as a
way to generate a crude flat spray pattern but
1
See patent #3,705,821 (Breer, 1972)
o
Benefits from lower overspray
• Increased transfer efficiency
results in material savings
• A cleaner workspace and lower
worker exposure to fumes and
mist
• Less frequent booth filter
changes
Benefits from lower fluid pressure
• Less pump wear - seals, other
sliding parts
• Lower air motor pressure
results in lower compressed air
consumption
Proper selection and use
To enable proper non-atomizing performance
the user should follow three simple rules:
Select the correct tip. The fluid tip must be
chosen carefully to minimize fluid pressure and
velocity and still provide the correct spray
pattern width for the required operation. All of
the Binks Century LEL guns use the same fluid
tip design. Gel coat guns will use tips with
smaller fluid channels and steeper impingement
angles, guns for GP resin will use larger
channels and medium impingement angles, and
guns for filled resins typically use very large
orifices and low impingement angles. The
customer should experiment with a range of
different tip sizes to optimize the spray pattern.
Use the lowest pressure possible. After
selecting and installing the tip in the gun the
system would be started up and resin pressure
should be gradually increased to generate a
spray fan similar to the one shown below.
An increase in fluid pressure increases the
velocity of the impinging fluid jets and increases
the fluid fan width. If the fan is too wide for the
flow rate required the emission rate will
increase and the user should change to a tip
with larger fluid passages and / or a smaller
impingement angle.
Refine and Record. The user should refine the
spray pattern with shaping air, if applicable,
then record the relevant setup parameters to
assure future non-atomizing performance.
Some items to record for future reference
include:
1. Pump air pressure
2. Catalyst percentage
3.
4.
5.
6.
7.
Fluid tip being used
Solvent tank pressure
Heater setting if applicable
Shaping air pressure if applicable
Other gun setup items (chopper position
and settings, static mixer length, etc.)
Testing and Verification of NonAtomizing Performance
The Binks Century LEL Internal Mix (102-3800
series) and External Mix (102-3600 series) Guns
were emissions tested in 2009 at
Industrial
Finishing’s Louisville, Colorado facility using
guidelines from the ACMA’s Styrene Emissions
Test Protocol. The Binks Century LEL Gel Coat
gun was emissions tested in 2001 and again in
2007 at Purdue University. The purpose of the
tests was to verify the performance of the nonatomizing technology as it relates to the “UEF
equations” provided by the EPA MACT
requirement for open molding of composites. In
each case, the gun was set up and operated per
industry best practices and the emissions were
measured via EPA method 25A, which is a
rigorous real-time method used to measure
hydrocarbon emissions in an exhaust stack. In
addition to method 25A, other EPA methods are
used:
• Use of EPA methods 204, 1, 2,
3(alternative), 4(alternative) for spray
booth air flow capture and
measurement.
• Styrene is the only monomer present in
the test resin.
• All material is applied to an ACMAdesigned three sided test mold.
• Spray technique follows elements of
ACMA’s “Controlled Spraying
Handbook”
All of the tests proved the different versions of
the Century LEL technology to emit styrene at
or below the levels predicted by the EPA UEF
equations.
The picture below shows the Century LEL
Internal Mix Gun (102-3825-1) applying
catalyzed resin and chopped glass to a “test
mold” designed by the ACMA and used in all of
the emissions tests for Binks LEL Guns.
Conclusions and
Recommendations
Any manufacturer using the Century LEL
technology for the open molding process to
make FRP parts may use the EPA’s UEF
equations to report their emissions. The Binks
Century LEL guns have all been tested per EPA
guidelines and have been proven to emit
monomer at or below the levels predicted by
the equations. The guns, therefore, meet the
EPA’s definition of Non-Atomizing Mechanical
Application per the Composites NESHAP.
Further, if the gun is properly set up and
operated it will meet the definition of nonatomizing per California AQMD rule 1162, which
states that a non-atomizing technique is a resin
application technique in which resin flows from
the applicator in a steady and observable
coherent flow without droplets for a minimum
distance of three inches from the applicator
orifice(s).
The complete emissions test report is available
from
Industrial Finishing upon request.
LEL Technology may be found in the following
Binks Century series guns:
102-3610 external mix LEL gel coat
102-3600 series external mix LEL (except 1023610) for wet-out and chop application
102-3800 series internal mix LEL for wet-out
and chop application
References
In the graph above, the red triangles represent
the data from the 2009 testing with the Century
LEL Internal Mix gun. The blue line represents
the emissions predicted by the NARA UEF
equation. In all test replicates, the Binks LEL
technology provided emissions much lower
than predicted.
Haberlein, Dr. Robert A., Test results: Styrene
Emissions from Mechanical Non-Atomized Resin
Applicators manufactured by
Industrial
Finishing, December 2009
EPA 40 CFR Part 63, National Emissions
Standards for Hazardous Air Pollutants:
Reinforced Plastic Composites Production,
Promulgated April 2003
AQMD rule 1162:
http://www.aqmd.gov/rules/reg/reg11/r1162.pdf