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Fiber Reinforced Plastic Shop Complies
with New Air Permit Regulations
Air permit requires
use of low styrene resins and nonatomized application equipment
| Company |
Sunrise
Fiberglass Company Wyoming, MN |
| Change |
Nonatomized
equipment replaced
spray equipment in open mold process. Low styrene
resin replaced traditional resin. |
| Cost |
$27,850
for new equipment, including nonatomized equipment
and in-line heater. |
| Benefits |
Styrene
emissions reduced by 43 percent. Met requirements
of new air permit. Cleaner to use. Increased material
efficiency. |
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Background Information
Sunrise Fiberglass, in Wyoming, Minnesota, produces fiber
reinforced plastic (FRP) parts in a 50-person job shop. The
parts vary in shape, size and end use.
Sunrise employs an open mold process which
uses about one and a half drums per day of resin and gelcoat
material. These materials were applied by spraying and resulted
in high styrene emissions. In 1999, nearly 36,000 pounds of
styrene were emitted.
Incentives for Change
The U.S. Environmental Protection Agency (EPA) classifies
styrene as a hazardous air pollutant. And, the proposed National
Emission Standards for Hazardous Air Pollutants (NESHAP) for
the reinforced plastics composites industry will limit styrene
emissions from FRP shops.
In order to upgrade its process and production
capabilities in 2000, Sunrise needed to relocate. Moving to
the new facility required a new air permit and compliance
with the NESHAP. Although the NESHAP is not yet finalized,
the Minnesota Pollution Control Agency (MPCA) looked to the
proposed rule when outlining Sunrise’s permit limits.
The new air permit required the use of low styrene resins
and nonatomized application equipment at Sunrise.
Process Change
Using low styrene resin
Styrene is a major component in resin. It lowers viscosity
for easier application and reacts with the polymer component
to form the rigid end product. In low styrene resins polymer
characteristics are changed to allow for a decreased styrene
content. The resulting low styrene resin has viscosity properties
similar to traditional resin and yields a similar finished
part.
Sunrise tested low styrene resins from a
variety of suppliers. Experienced operators gave feedback
on application characteristics and managers evaluated the
quality of finished parts. A general purpose resin capable
of yielding appropriate physical properties, at a comparable
cost to traditional resin, was selected. This general purpose
resin contained 38 percent styrene compared to traditional
resin's 43 percent.
Choosing nonatomized
application equipment
Traditional application equipment requires high fluid pressure
and/or air to properly mix the resin with the catalyst to
form an appropriate spray pattern as they exit the gun. These
finely dispersed spray droplets have a large surface area,
allowing styrene to evaporate. Even the smallest droplets
become overspray. But, nonatomized application equipment mixes
the resin and the catalyst together in an internal chamber.
The mixture exits the chamber in a continuous low pressure
stream which greatly reduces the surface area for evaporation.
And, finely dispersed droplets are negligible, resulting in
decreased emissions. Internal mixing of the catalyst also
cuts the amount of "free catalyst" entering the
work environment, reducing health and flammability concerns.
Sunrise had the option to upgrade its old
application equipment to meet the permit requirements with
modifications like different gun heads and metering pumps.
But, because of the limited cost difference, the company decided
to purchase new, state-of-the-art nonatomized equipment. Sunrise
employees tested various equipment on site using low styrene
resin. Sunrise chose the Magnum Venus Products fluid impingement
technology (FIT) system because it was economical and the
most current technology. Magnum FIT has minimal overspray
in the form of fog or finely dispersed particles and operators
were impressed with its clean application.
Implementation Issues
Wet out
With nonatomized application equipment the resin has less
opportunity to coat the glass as the mixture is applied to
the mold. As the part sits, the resin coats the glass. Because
the glass appeared to be under saturated with resin, the operators'
initial tendency was to apply more resin. This used excess
materials and created “heavy” parts. After operators
were educated on the issue, part weights were on target and
consistent.
Resin temperature
sensitivity
Low styrene resin is slightly more viscous—but comparable—to
traditional resin. In order to preserve suitable viscosity
for any resin, temperatures must be maintained within a narrow
range. A resin temperature that is too cool significantly
affects its application characteristics, and too high of a
resin temperature leads to premature polymerization during
storage. Low styrene resin is more sensitive to temperature
than traditional resin. For the best working characteristics,
traditional resins should be kept between 68 and 80F, and
low styrene resins between 75 and 80F.
Sunrise worked with its supplier to ensure
that resin was delivered within the desired temperature range.
Because the company does not have a good means to heat bulk
resin in storage, the company specified a delivery temperature
closer to 80F to avoid excessive temperature drops in cooler
months.
One of Sunrise's products requires a special
low styrene resin that is extremely sensitive to temperature.
In order to achieve an acceptable production rate and part
quality, Sunrise needed to control the resin temperature for
proper dispensing. An electric, in-line heater was added on
the resin transfer line ahead of the application equipment.
The unit was selected for ease of maintenance.
Perceived hazardous
waste increase
Because the FIT's internal mix chambers require frequent flushing
with acetone, Sunrise originally anticipated an increase in
hazardous waste. But, the mixing chambers have an air purge
that blows out the residual catalyzed material, limiting the
volume of acetone needed for thorough cleaning. And, FIT produces
little overspray so general cleanup using acetone is greatly
reduced. This helped keep acetone use from increasing.
| Cost
and Benefits |
| • |
$26,600 spent
for seven nonatomized FIT guns and $1,250 for one in-line
heater. Low styrene resins cost the same as traditional
resins. |
| • |
Less overspray
equals savings in resin and glass, and acetone for cleanup.
Less labor is devoted to overspray cleanup. |
| • |
Styrene emissions reduced
43 percent. In 1999, total styrene emissions exceeded
36,000 pounds. Using 1999's resin and gelcoat use levels
and emissions factors for new equipment and resins, styrene
emissions would drop to 20,500 pounds. |
| • |
Material savings
in excess of $12,000 per year are anticipated. Based on
resin consumption, low styrene emissions can lead to product
yield improvements of five to 10 percent. Glass/filler
to resin ratios need to be re-calibrated to realize these
savings. Payback is about two to three years, or less. |
| • |
Met requirements
of new air permit without lost production time, excess
capital costs or employee issues accepting the new technology. |
| • |
Less blow back
of material—less material bounces back toward operators
after hitting the part during application. This improved
working conditions, earning operator acceptance of the
new technology. And, less employee protection equipment
is needed. |
Additional Efforts
Sunrise continues to investigate other possibilities to reduce
emissions, including options for styrene reduction in gelcoat
application. A large decrease in these emissions could result
if nonatomized equipment for gelcoat application is used in
conjunction with low styrene gelcoats.
MnTAP has a variety of technical assistance
services available to help Minnesota businesses implement
industry-tailored solutions that maximize resource efficiency,
prevent pollution and reduce costs. Our information resources
are available online. Or, call MnTAP at 612/624-1300
or 800/247-0015 from greater Minnesota for personal
assistance.
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