Date: September 2, 2008 (Finalized: December 8, 2008)

Subject: Site Visit – Lawrenceville Br ick, Inc. Lawrenceville, Virginia Brick and Structural Clay Products Manufacturing NESHAP EPA Contract No. EP-D-06-118; EPA Work Assignment No. 2-09 RTI Project No. 0210426.002.009

From: Richard Marinshaw Tom Holloway Gabrielle Raymond

To: Jeff Telander EPA/SPPD/MMG (D243-02) U. S. Environmental Protection Agency Research Triangle Park, N.C. 27711

I. Purpose

The purpose of this visit was to observe the brick manufacturing process at the Lawrenceville Brick, Inc. (Lawrenceville) facil ity and to collect information on sources of hazardous air pollutant (HAP) emissions and emissi on controls in support of the redevelopment
of national emission standards for hazardous air pollutants (NESHAP) for the brick and structural clay products industry.

II. Place and Date

Lawrenceville Brick, Inc. 16024 Governor Harrison Parkway Lawrenceville, Virginia 23868

July 30, 2008

III. Attendees

Lawrenceville Brick

Leon Williams, Senior Vice President-Production Telephone: (434) 848-3151

Bill Parrish, Safety and Environmental Manager

Sam Lewis, Plant Manager, Plant 32

Darren Talbert, Plant Manager, Plant 4

The Brick Industry Association (BIA)

Terry Schimmel, Boral Bricks, BIA MACT Task Force Lead Telephone: (334) 480-2488

U. S. Environmental Protection Agency

Jeff Telander Telephone: (919) 541-5427

RTI International

Tom Holloway Telephone: (919) 316-3733

Richard Marinshaw Telephone: (919) 316-3735

Gabrielle Raymond Telephone: (919) 541-7015

IV. Discussion

A. Background

The Lawrenceville Brick, Inc. facility, locat ed in Lawrenceville, Virginia, manufactures several products, including face brick, building bric k, pavers, structural brick, and other shapes. The Lawrenceville facility consists of two plants: Plant 3 and Plant 4. Plant 3 includes a natural gas-fired tunnel kiln that ha s a production capacity of 129,648 tons per year (ton/yr) of fired brick. Plant 3 has been operati ng since the 1990’s. Pl ant 4 includes a similar-sized natural gasfired tunnel kiln with a production capacity of 129,648 ton/yr of fire d brick. Plant 4 was built in 2003. Both plants are currently ope rating at about 60 percent capacity.

The facility operates 24 hours per day, 7 da ys per week; brick forming and firing operations operate continuously, while the mining a nd raw material operations operate 5 days per week, or as needed depending on the production schedule. Lawrenceville employs up to 140 employees at the facility.

B. Process

Lawrenceville manufactures structural bricks in both plants, and the same basic process is used for producing bricks at each of the plants. The primary difference between the two plants is the degree of automation; in Plant 4, much more of the equipment is automated than in Plant 3. The process steps include raw material storag e, crushing, screening, grinding, mixing, forming, drying, and firing. The following para graphs describe structural bric k production in more detail.
Attached is the non-confidential handout provided by the BIA at th e start of the site visit.3

Lawrenceville uses a combination of 40 percen t shale and 60 percen t clay to manufacture bricks. The shale used by Lawrenceville is actually a type of hard schist. As a result, clay is added to provide enough plasticity to the mixtur e for shaping. In additi on, the green brick must be fired at a higher temperature th an is typical for a Triassic shal e. The raw materials are mined at two different locations, each of which is about 15 minutes away from the facility. Each mine has about a year’s worth of mate rial stockpiled. The raw material s are trucked to the facility where a 3-week supply of shale and a 1-month supply of clay are maintained in covered storage.

The following paragraphs describe the operations performed in the two plants. Plant 3 is described first, followed by the description of Plant 4.

1. Plant 3. The raw material is first transf erred to a primary crusher, which reduces the material size from up to 18 inches to a bout 4 inches. The crusher has a capacity of approximately 300 tons per hour (ton/hr). The material is transported by conveyor to the grinding room. In the grinding room, the material is fed to a series of screens, where oversize
material is transferred to a hamm ermill, and undersize material is tr ansferred to finishing screens. The hammermill has an operating capacity of 275 ton/hr. The ground material is transported by conveyor and front end loader to the forming area. Here, the mois ture content, typically about 13 percent, is measured, and body additives and co lorants, such as soda ash, manganese dioxide, and iron oxides, are added. The material is fed into a pug mill, where the raw material is mixed
with water to raise the moisture content to abou t 18 percent. The material is vacuum-extruded from the pug mill as a continuous column onto an open conveyor belt. Liquid and powder can be added on top of the column to add color to the bricks. The column may also pass through a
roller to add texture to the bricks . The next step is cutting. The column is cut into slugs, and then cut by wire into 30 individu al “green” bricks. The green br icks travel by conveyor to the setting machine, where they are automatically set on th e kiln cars. Netting is wrapped around the stacks of brick to provide more stability to the stacks during drying a nd firing. Another option for the green bricks is to be cut again manually to create unique shapes. This is only for special
orders.

The kiln cars loaded with green bricks are next rolled down a track to the dryers. Drying typically takes about 2 days and is complete when the bricks have reached a moisture content of 1 percent. The dryers are heated with waste heat from the cooling zones of the kilns. The kiln cars then are mechanically rolled out of the dryers and into the tunnel kiln, where they are fired.

After drying, the kiln cars loaded with the dried brick are pushed through the kiln according to a set schedule. The temperature within the kilns varies along the length of the kiln. From the entrance, the temperatures within the kiln are ramped up to a maximum in the firing zone, which is maintained around 2030  F. After the firing zone, th e kiln temperature decreases gradually until the bricks enter the cooling zone of the kiln. After cooling, the cars exit the kiln
and are rolled outside the kiln to an unloadi ng area. There, the bric ks are manually unloaded from kiln cars, packaged, and transported to an open storag e area outside the covered plant.

2. Plant 4. The process used in this plan t is similar to the brick manufacturing process that is used in Plant 3. However, Plan t 4 is largely automated, so most of the manual operations that are performed in Plant 3 are perf ormed robotically in Plant 4. The raw material crusher, grinder, and screens ha ve similar capacities to the equipm ent in Plant 3. However, after4

grinding in Plant 4, the material is stored in a series of zone s in the reclaim building. An
automated reclaimer withdraws the material from storage and transfers it to a conveyor, which then transports it to the brick forming area. The forming, drying, firing, and packaging steps of the process are similar to those described above for Plant 3.

C. Emissions and Controls

The primary emission units are the kilns. Emissions from the tunnel kiln in Plant 3 are controlled with a dry limestone adsorber (DLA), which was retrofitted in 2006. Emissions from
the tunnel kiln in Plant 4 are co ntrolled with a dry injection fa bric filter (DIFF), which was
installed with the kiln in 2003. Lawrenceville de cided to install a DIFF instead of a DLA on the
Plant 4 kiln to ensure the kiln could meet the proposed emission limit for hydrochloric acid (HCl). However, the final rule specified a less stringent HCl emission limit, which the plant could meet using a DLA. Although both the DLA a nd DIFF were installed to comply with the original NESHAP, the facility is now classified as a synthetic minor source. The operation of the DLA and DIFF is described in the following paragraphs.

In the DLA, limestone is fed into a reaction chamber at the top of the unit at a rate of 157 pounds per hour (lb/hr). The limestone ca scades through multiple baffles within the
chamber and reacts with the exhaust gases from the kiln, which flow across the reaction
chamber. When the limestone reaches the bottom of the chamber it is transferred by augur to a descaler, which is equipped with serrated blades to remove the r eacted material on the surface of the limestone. The processed limestone is then conveyed pneumatically b ack to the top of the
reaction chamber. New limestone is periodically added to the system as needed, as reacted limestone is removed. Lawrenceville obtained ap proval from the State for alternative monitoring of the DLA operation. Rather than monitor pr essure drop across the DLA, the plant must monitor the bypass damper position. In addition, the plant uses level indicators to monitor and ensure there is adequate li mestone in the feed hopper.

In the DIFF, the exhaust gases enter a reacti on chamber, where hydrated lime is fed at a rate of 89 lb/hr. The exhaust gases then ar e pulled through a pulse-jet fabric filter, where reaction products and other particulate matter ar e removed from the exhaust stream. The lime that is not carried by the exhaust gas stream in to the fabric filter is collected in a hopper and recirculated through the system. Fresh reagent is added at a ratio of 10:1 (recirculated to fresh reagent). The fabric filter includes 768 bags made of polytetrafluoroethylene (PTFE), which have a maximum operating temperature of 500°F. Lawrenceville has not determined the average lifetime of the filter bags, but noted that a full set of bags for the DIFF costs approximately $150,000.

Waste material from the DLA and DIFF is shipped off-site for agricultural applications. In addition, Lawrenceville is currently working with Virginia Tech to develop options for selling
the waste material as a soil amendment.

Plant personnel pointed out that the costs to install and operate the DIFF at Lawrenceville have been significantly higher than the costs to in stall and operate the DLA. The installed cost for the DLA was approximately $900,000, and the installed cost for the DIFF is about $1,300,000 in today’s dollars. The annual operati ng costs for the DIFF are about $150,000 more5

than the costs to operate the DLA. One differe nce in operating costs results from the need to replace fabric filter bags peri odically, which is estimated to be about $50,000 per year on average for replacements. Another difference in op erating costs results from the larger exhaust fan motor in the DIFF. After an 18% increase by Virginia Dominion Power, the electrical costs for the DIFF are now about $60,000 more per year than for the DLA. The remainder of the additional costs is mainly for the higher costs of the hydrated lime versus the pellet lime used in the DLA. Labor costs for normal operation are no t included in this anal ysis. In addition, the
exhaust into the DIFF must be maintained at a temperature high enough to preclude acid gases from condensing within the fabric filter and de stroying the bags. To ensure adequate inlet temperatures, the system is equipped with an auxiliary burner to heat the inlet air when necessary. Lawrenceville continuou sly monitors the pressure drop across the fabric filter, and filter bag cleaning is triggered when the pres sure drop exceeds the set point for the system.

Stack tests on the two kilns indicated the DIFF- controlled kiln has HF emissions of about 0.45 ton/yr, and the DLA-controlled kiln emits about 0.65 ton/yr of HF. Uncontrolled HF
emissions from each of the k ilns are about 22 to 25 ton/yr.