|
Fiber Reinforced Plastics 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. |
|
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
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.
For More Information
Other MnTAP publications for the FRP industry:
MnTAP has a variety of technical assistance services available to help Minnesota businesses implement industry-tailored solutions that maximize resource efficiency, prevent pollution, increase energy efficiency, 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.
|
|
Fiber Reinforced Plastics
Closed Molding
Open Molding
Scrap
Volatile Emissions
Training & Associations
Regulatory Information
A to Z Waste Topics |
