Document ID: EPA-HQ-OAR-2008-0053-0074
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-06-01T04:00Z

SEQ CHAPTER \h \r 1 MEMORANDUM

DATE:	June 24, 2008

SUBJECT:	Trip Report for the Site Visit to W.C. Richards Company in
Aberdeen, North Carolina, on May 7, 2008

  SEQ CHAPTER \h \r 1 

FROM:	Bradley Nelson, EC/R Inc.

TO:		Melissa Payne, EPA/OAQPS/RDPAG   SEQ CHAPTER \h \r 1 

1.0	PURPOSE

The purpose of this visit was to examine the paint manufacturing process
at a small (area source) paint manufacturing facility.  This included
examining any emission control equipment and pollution prevention
measures that are in place.  The visit also included a discussion of the
costs incurred from using these pollution control measures and the
wastes generated as a result of the pollution control measures.

2.0	PLACE AND DATE

	W.C. Richards Company

	101 East Maple Street

	Aberdeen, NC 28315

	May 7, 2008

3.0	ATTENDEES

	W.C. Richards Company

	

	William Abel, Plant Manager

	Paul Puszynski, Plant Supervisor

	National Paint and Coatings Association

	

	David Darling, Director, Environmental Affairs

	Alison Keane, Counsel, Government Affairs

	John Hopewell, Manager, Environmental Affairs

	

U.S. Environmental Protection Agency

Melissa Payne, EPA/OAQPS/RDPAG

Barry Elman, EPA/OPEI/SSD

EC/R Incorporated

Bradley Nelson

4.0	DISCUSSION

A.	Overview of Facility and Products

	The W.C. Richards facility produces specialty coatings for industrial
companies.  The company custom formulates coatings based on the
requirements and specifications of the industrial customer.  The company
produces conventional solvent based products, water reducible and water
emulsion products, high solids solvent based coatings, and unique high
performance products.  The facility currently employs 14 people at the
manufacturing facility.

The company produces approximately 150,000 gallons of coating each year
with batch sizes ranging from 1 gallon to 1,000 gallons.  The company is
equipped with 7 stationary mixing tanks and 12 portable mixing tanks to
produce the coatings.  The portable mixing tanks range in size from 30
to 300 gallons and are used for smaller batches.  The stationary mixing
tanks are generally used for larger batches and are approximately 500
gallons in size.

B.	Emissions and Controls

The facility is an area source of hazardous air pollutants (HAP) with
air emissions of 1,030 pounds for toluene, and 755 pounds per year of
xylene.  These emission estimates were calculated using the AP-42
emissions factors for paint manufacturing.  The facility is equipped
with a baghouse that captures particulates from the mixing process using
a flexible duct hoses that can be moved to different mixers.  The
baghouse system has been in place for over 25 years and was installed to
protect workers from exposure to toxic particulates.  The plant manger
estimated the cost of the baghouse and exhaust duct system to be
$75,000.  The company also uses plywood covers on the process tanks to
reduce the evaporation of volatile organics from the coatings mixture. 
The company estimated that nearly 4% of the volume of the coating is
lost during the manufacturing process.  The losses occur due to
evaporation of volatile chemicals, residue materials remaining in empty
containers (i.e. pigment bags, drums, etc.), materials retained in mill
chambers (this material is pumped out and segregated at the beginning of
the next batch and used for cleaning or placed in hazardous waste), and
unrecoverable losses in the filtering process.  Volatile chemicals used
in the manufacturing process are stored in covered containers.

C.	Manufacturing Process

	Four main steps are used to manufacture paint at W.C. Richards: (1)
premix, (2) letdown, (3) quality control, and (4) filling.  Equipment
used for paint manufacturing includes bulk solvent storage tanks, bulk
resin storage tanks, small container raw material storage, portable
process tanks, stationary process tanks, high speed dispersers (HSDs),
vertical sand mills, pebble mills, and packages and containers for
product shipment.

1.	Raw Material Storage and Assembly

Bulk raw materials are stored in 3,800 gallon tanks.  The facility uses
four tanks for solvents and two tanks for resin.  The tanks are filled
from tanker trucks.  Solvent tanks are located outside and resin tanks
are located inside of the facility.  A dyke surrounds each group of bulk
storage tanks.  A piping system ending in a manifold brings raw
materials from the bulk storage tanks to the manufacturing area.  During
assembly of raw solvents and resins, a portable process tank is rolled
onto a scale underneath the manifold.  Bulk raw materials are released
from the manifold into the process tank.  After filling, a small bucket
is placed under the manifold to catch any drips of material.

Packages of pigments and empty containers are stored in a building apart
from the main building.  Any flammable materials are brought into the
main building because it is equipped with a sprinkler system.  Purchase
orders and batch tickets list a coded set of ingredients.  All packages
of pigments are labels with the same codes used on the batch tickets. 
During assembly of pigments, the worker uses an electric scale to weigh
out the amount of pigment specified on the coded batch ticket into a
paper grocery bag.  The assembled raw materials are set on a pallet and
brought into the production area.  Most of the pigments used at W.C.
Richards do not contain hazardous metals.  However, to meet the
requirements of certain end-users, some pigments containing hazardous
metals are used at the facility.  The plant manager estimated that less
than 1,000 pounds of pigments containing hazardous metals are used per
year.  At one point, a surcharge was levied on products that contained
heavy metals to offset the waste disposal costs incurred by the facility
for disposal of hazardous wastes and to encourage customers to allow
W.C. Richards to substitute alternative materials for the hazardous
pigments.  Due to increased competition from other manufacturers, W.C.
Richards is no longer able to levy the surcharge.

2.	Premix

W.C. Richards has both portable and stationary process tanks.  Two of
the largest stationary tanks are used on a regular basis.  During
premix, resins, wetting agents, and pigments are loaded into the
portable process tank.  A flexible vent hose is placed near the opening
of the tank as pigments are loaded to capture and vent dust into a
baghouse.  The portable process tank is placed under a stationary HSD. 
The agitator shaft of the HSD is lowered into the process tank and mixes
the raw materials.  All process tanks are covered during mixing.  Some
products require a milling stage following mixing with the HSD to
further disperse the pigments.  While the milling stage is generally
conducted after the HSD process, sometimes raw materials are blended in
a mill as a first stage.

Both vertical sand mills and pebble mills are used at the facility for
grinding.  If a vertical sand mill is used, the portable process tank
containing the intermediate product is rolled near the mill.  A flexible
hose is used to transfer the intermediate product from the portable
process tank and into the bottom of the mill.  The intermediate product
is pumped up through a cylinder filled with media and a series of discs
connected by a shaft.  A screen surrounds the cylinder to hold in the
media.  The discs are rotated to act similarly to the agitator shaft of
an HSD.  Pigments are dispersed as the intermediate product flows
through the media-filled cylinder.  The product is then pumped from the
top of the mill through a flexible hose and into a second portable
process tank.  Using the vertical sand mill, the grinding process
requires only the time necessary for the intermediate product to flow
through the mill.  If the pebble mill is used for grinding, the
intermediate product is loaded into the mill and is dispersed at one
time.  As the mill circulates, the media disperses the pigment.  The
grinding process requires one or two days using the pebble mill.  While
heat-up from the grinding process itself is sufficient for grinding
using the vertical sand mill, if the pebble mill is used for grinding
the HSD must be used as a first stage to ensure that the temperature of
the intermediate product is at least 120 degrees when it is loaded into
the pebble mill.  Water jackets are used to prevent excessive heat-up
during use of the vertical sand mill.

Portable process tanks and mills are cleaned to avoid contamination from
batch changes.  Recycled solvent is typically used for this cleaning
operation.  Once the recycled solvent is spent it is stored for
incineration.  Mills are cleaned using batch solvent.  The batch solvent
is used to flush the mill and is then added to the letdown tank or used
in another batch.  If water is used instead of solvent to clean the
tanks and mills after production of waterborne paint, the wastewater can
be combined with solvent stored for incineration.  To clean the agitator
shaft on the HSD, a drum with solvent is placed under the shaft.  A
brush is dipped into the solvent and brushed along the agitator shaft to
remove residual materials.  The plant manager attempts to schedule paint
production from batches of light colors to dark colors to reduce the
frequency of cleaning.

3.	Letdown

After premix, the next step of the process is called letdown.  During
this stage, remaining ingredients are added to the intermediate product
to bring the batch to its final volume.  The materials are added into
the same portable process tank that was used for premix.

4.	Quality Control

Following letdown, a sample of the product is tested in the quality
control (QC) lab.  Each formulation is quality tested for a series of
parameters including color, sag, viscosity, and grind.  Small ovens are
used to force samples to dry and for testing baking enamels.  After a
batch passes QC, a sample of the final product is kept for one year. 
The first time a new formulation is created, the paint manufacturing
process is carried out in a small scale in the QC lab prior to
production of the full batch size.

5.	Filling

After a batch passes QC, it is filled into containers of various sizes. 
All filling is conducted by hand as the facility does not have
sufficient production volume to warrant the use of automated equipment. 
The final product is filled into one gallon containers, five gallon
containers, or drums.	

5.0	SUMMARY

The W.C. Richards Company manufactures specialty coatings for industrial
customers.

The W.C. Richards facility is an area source and employs 14 people.

The main stages of the coatings production involve: (1) the blending of
liquid media with the pigments and resins in the sand mill or high speed
disperser; (2) the addition and mixing of tints and solvents; (3) the
product filling stage.

The facility uses 7 stationary process tanks, 12 portable process
vessels, five sandmills, and four high speed dispersers to produce
approximately 150,000 gallons of coatings a year.

Control of volatile HAP is achieved by using process tank covers.  Using
the covers the facility estimates they lose approximately 4% of the
coating product.  The losses occur due to evaporation of volatile
chemicals, residue materials remaining in empty containers, materials
retained in mill chambers, and unrecoverable losses in the filtering
process.  

A baghouse and flexible vent system is used to control the emissions of
particulate HAP.

 Based on the toxic releases for reporting year 2006 reported in the EPA
Envirofacts Data Warehouse.

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