PERMIT MEMORANDUM 93-065-C (M-5) DRAFT 6
OKLAHOMA DEPARTMENT OF ENVIRONMENTAL QUALITY
AIR QUALITY DIVISION
MEMORANDUM April 25, 2008
TO: Phillip Fielder, P.E., Permits and Engineering Group Manager,
Air Quality Division
THROUGH: Kendal Stegmann, Senior Environmental Manager,
Compliance and Enforcement
THROUGH: Jian Yue, P.E., Engineering Section
THROUGH: Phil Martin, P.E., Engineering Section
THROUGH: Peer Review
FROM: Charles Stockford, P.E., Existing Source Permits Section
SUBJECT: Evaluation of Application No. 93-065-C (M-5)
Temple-Inland Forest Products Corporation
Fletcher Gypsum Wallboard Plant
Section 11-T4N- R10W; Latitude 34.841°N, Longitude 98.227°W
Fletcher, Comanche County
Located one mile Northeast of Fletcher on Highway 277
SECTION I: INTRODUCTION
Temple Inland Forest Products has submitted an application for a Title-V & Construction permit request to the Oklahoma AQD for a production and plant expansion at the Fletcher, Oklahoma facility. The applicant requested additional changes to the permit during the Public Review Period. The changes which ease the limits on CO and NOx for the existing wallboard dryer will require the permit to be resubmitted for a second public review cycle. The requested changes have been incorporated into the permit. The specifics on the changes are in Section X of the memorandum.
The primary activity at the plant is gypsum wallboard production (SIC 3275). The plant is currently operating under Permit No. 93-065-O (M-4) issued on October 10, 2007. The original permit (Permit No. 84-063-O) was issued in April of 1987 in the name of Temple-Eastex, Incorporated, and amended in June 1989 to reflect the applicability of NSPS Subpart OOO based on a determination by EPA. EPA Region VI Chief, ALO Enforcement Section of the Air Enforcement Branch ruled that “...the Stationary Source Compliance Division finds that calcium sulfate operations are subject to NSPS standards where all other criteria are met.” Temple Inland has since conducted the required testing to demonstrate compliance. In 1990, the company requested a modification and installed a baghouse on the stucco cooler. In 1993, a construction permit was issued to construct a new wasteboard recycling line, and the operating permit was issued in 1995. In 1998, the permit was modified to increase production, reflect emissions based on June 1998 testing, and correct errors in the previous permit. The most recent permit allowed for the replacement of the current wallboard dryer burners with more efficient units. The plant is currently classified as a synthetic minor facility. Plant output will be increasing from 713 MMSF/year (1/2” thickness basis), to 800 MMSF/year (1/2” thickness basis). In addition calciner throughput will increase from 613,200 TPY to 700,800 TPY, with a maximum hourly capacity of 100 tons. The project is anticipated to begin 1st Quarter 2009, and be in full operation by April of 2010. The proposed changes do constitute a major modification, but they are not subject to PSD requirements.
SECTION ii: cHANGES TO FACILITY
Additional equipment will be required to process the increased capacity, creating additional emission points. The following equipment will be added at the facility as part of the expansion.
· Calciner w/cyclone & Baghouse - #83 Raymond Imp Mill Flash Calciner System with Low-NOx Mason 25 MMBTUH Burner.
· Dryer – GYPTech 10 deck dryer w/Eclipse Burner rated at 78 MMBTUH natural gas firing capacity.
· Stucco Cooling System w/baghouse – Raymond pulse jet collector 32,000 acfm.
· Take-Off Dust Collection (Edge Trim) Baghouse – CECO air pulse jet 8,000 acfm.
· Additional Reclaim Equipment including new reclaim hopper, bucket elevator, in-feed screw, bucket elevator conveyor, and calciner in-feed screw.
· The production building will be expanded, existing conveyor systems modified and new conveyor systems added, along with an additional hammermill.
sECTION iii: Process Description
The specific operations used to manufacture gypsum wallboard include gypsum handling, calcining, blending and forming, drying and cooling, and bundling which are described below:
a. Gypsum Handling - Fine raw gypsum rock is received from local mines in the area via tarped trucks. The gypsum (CaSO4 + 2 H2O) is drop loaded from the trucks into a “below track” hopper contained inside a covered building, picked up by conveyor, and transferred into the enclosed rock storage building by covered conveyor.
Gypsum is retrieved from storage by front-end loader, and fed through the coarse screens and hammermills. All rock less than 0.25” passes through the screen. The hammermills are set for a minus 0.25” discharge, which is blended with the original 0.25” and smaller material for transport to the calciners. This process is totally enclosed except the front-end loader transfer operations.
b. Calcining - The material is fed into one of four natural gas-fired calciner/milling systems where it is flash calcined and reduced down to a particle size that will pass through a 100 mesh screen. The material is now called stucco (CaSO4 + ½ H2O). The stucco is pneumatically and mechanically conveyed to storage with the separated exhaust/conveying air passing through a cyclone and a bag filter for dust control and additional stucco collection (BH-127, BH-129, BH-130, and BH-131(new)). Approximately 60% of the bag filter exhaust air is returned to the calciner gas heater units to increase energy efficiency. The entire stucco handling system is under negative pressure with all exhaust air vented through a bag filter (CBE-7907).
Each of the calciners has a 25 MMBTUH natural gas-fired burner. All four calcine mills are each equipped with a baghouse for control of particulate emissions and designated BH-127, BH-129, BH-130, and BH-131(new). All four calciners operate simultaneously year-round while all four natural gas-fired burners will be fired continuously when the calcine mills are in operation. Two air-cooled stucco coolers allow moisture to dissipate before entering the stucco storage area. Reducing moisture also reduces the potential for plugging problems. Emissions from the stucco coolers are controlled by baghouses DC-170, and DC-180(new).
c. Blending and Forming - Stucco is withdrawn from the storage bins and transferred to the blending area, mixed with starch, ball mill accelerator (BMA), vermiculite, glass fibers, water and/or other additives depending on the grade of board being manufactured. Starch is stored in a 200,000-lb storage tank and conveyed to the blending area. The starch tank and starch conveying system are equipped with a baghouse to control dust emissions (DV-007). BMA is raw gypsum that is crushed in the ball mill and combined with sugar prior to being stored in the BMA tank. Dust from the pin mixer vent and the dry additives screw conveyors are also controlled by a baghouse (BCA-500). Additional wet additives, such as soap, paper fiber as pulp, and detergents are introduced into the mixer.
The slurry of plaster and additives is delivered onto a moving sheet of paper. An additional roll of paper adds a second covering to the top side, and the basic gypsum wallboard is formed in a continuous strip. This is conveyed down a several hundred foot carrier belt to allow time for curing of the plaster to its initial set. Rotary knives cut the continuous board to length. The wet transfer system accelerates the board through a right angle transfer station, inverts each board, and pairs it face up, two-wide for delivery into the dryer.
d. Drying and Cooling - The wallboard dryers have three heat zone direct heated drying tunnels, through which the board is conveyed by chains and rollers. Heat moves through the dryers in a counter current flow creating a more energy efficient situation. The exhaust is delivered through all three zones and exits each dryer through one stack. There is a “seal” section at each end of the dryer. The main exhaust damper balances pressure in this “seal” section and creates a situation where there is negative pressure in the seals. Each dryer has three natural gas-fired burners, with a total rated firing capacity of 85 MMBTUH and 78 MMBTUH respectively for No.1 and No.2 dryers. Upon exiting the dryers, additional conveying area allows some cooling of the board before being sent back into a single stream, two boards wide.
Table - 1 Wallboard Dryers #1 & #2 Burner Heat Capacities
Heat Input / Zone 1 / Zone 2 / Zone 3No. 1 Rated / 23 MMBTUH / 48 MMBTUH / 14 MMBTUH
No. 2 Rated / 31 MMBTUH / 31 MMBTUH / 16 MMBTUH
e. Finishing - The pairs of boards are cross transferred and stacked in twos, face-to-face, the ends taped for sealing and bundled together for shipping. An automated stacker arranges the bundles of boards for storage or shipping. Reject board from the bundling area is broken up by a crusher and hammermill and delivered back to rock storage. The dust from the end trimming saws is collected by a bag filter designated DRA 200/250.
The finishing area also includes the production of sleuters, which are 4” wide strips of reject board used as spacers between units of finished wallboard. There are four sawing stations where the sleuters are produced. Most of the dust from this operation is collected and routed to the end saw bag filter (DRA 200/250). The residual dust settles on the floor and is swept up for disposal.
f. Storage Tanks - Fuel storage operations include diesel and gasoline storage and dispensing. These fuels are used in plant utility mobile equipment. Tank storage operations also include the dry and wet additives used in the stucco blending process. All of these tanks are fixed roof atmospheric tanks. Details on the tanks and capacities are shown in Table-6.
sECTION iv: Emissions
Temple-Inland’s Fletcher Wallboard facility has emissions from several different operations and process units. For simplicity, a short discussion of each source (both those with and without changes) and its emission basis precedes the table showing individual unit emissions and its changes. The basis for all calculations is: 100 tons per hour total of dry gypsum rock (stucco) for the calciners; annual production of 700,800 tons of dry raw gypsum rock (stucco); maximum board production rates through the dryer of 96.0 MSF/hr and 800 MMSF/yr (both on a ½” thickness basis); and continuous operation. Emissions from the specific processes have been calculated as follows:
a. Gypsum handling - Gypsum handling includes all of the transfer points of raw gypsum from the time it is received until it is fed through the coarse screens and hammermills. This includes the transfers by front-end loader between the rock storage building and the coarse screen. The PM emission factor for these activities is based on equation 1 in AP-42 (11/06), Section 13.2.4.3. All transfers except the front-end loader have a conservative 50% control efficiency applied to the activity since operations are enclosed either in a building or a covered conveyor. Actual control will probably be much higher.
b. Calcining - The calcine mills are sources of PM, SO2, VOC, CO, and NOx emissions. The PM emissions are based on a modified AP-42 (1/95), Table 11.16-2 emission factor for impact mills with cyclones and baghouse efficiencies of 99.7 %. Based on process experience, a 50 lb/ton emission factor was used versus the published 100 lb/ton of stucco. This PM emission factor was confirmed via stack testing on one of the calciners on November 10, 1999. The VOC and CO emissions are based on results of testing conducted on June 16-17, 1998. During the testing, samples were taken under two different operating conditions to determine the effects of adding 5% recycled asphalt board (asphalt makes wallboard water-resistant) and spent oil-dry to the raw gypsum feed. Maximum oil-dry added would be 1000 pounds per month of which a maximum would be 15% oil by weight or 150 lb/mo. The VOC emissions showed an increase when these additional feeds were processed; therefore, the VOC emissions are based on this operating scenario. The emission factors for VOC and CO are based on the highest emission rate observed during the test. The SO2 and NOx emissions are based on AP-42 (3/98) emission factors for natural gas combustion. The increase in these pollutants is due to the increased production, the additional calciner, and the addition of the process variability factor.
c. Stucco Cooling - The PM emissions from the stucco coolers are based on the inlet loading to the baghouses and the control efficiencies. The inlet loading to the stucco cooler baghouses was based on vendor information and maximum stucco production of 100 TPH. The control efficiencies of the stucco cooler baghouses are 99.9%. To allow the facility optimum flexibility, the calculations presented assume that each stucco cooler is capable of handling the maximum stucco throughput. As a result, these emission rates are not additive when determining total emissions.
d. Stucco Storage - The PM emissions from the stucco storage bins baghouse are based on the NSPS limit of 0.05 g/dscm for nonmetallic mineral storage bins (Subpart OOO). The only changes with this source result from the increase in production.
e. Starch Tank - The PM emissions from the starch storage tank baghouse are based on an engineering estimate that corresponds to a control efficiency of 99.98% (calculated). There are no changes from the previous permit for this source.
f. Area Cleanup - The PM emissions from the area cleanup baghouse are based on an inlet loading to the baghouse and the permitted control efficiency. This source controls dust emissions from the pin mixer and from the additives screw conveyors. This operation is directly related to board production. The inlet loading to this baghouse is based on the total board production.
g. Wallboard Dryer - The wallboard dryers are a source of PM, SO2, VOC, CO, and NOx. The PM and VOC factors are based on testing conducted on July 23, 2007. The emission factors for SO2 and CO are based on manufacturer’s guarantees. The emission factor for NOx is based on AP-42 (3/98) emission factors for natural gas combustion. The emissions increases for these pollutants are due to the revised total burner firing capacity of 85 MMBTUH for unit No.1 and 78 MMBTUH for unit No.2.
h. Reclaim/Edge Trim - The PM emissions from the reclaim/edge trim baghouses are based on inlet loading to the baghouses and the permitted control efficiency. The inlet loadings (maximum and average) are based on June 1998 testing, and adjusted based on production ratio increase.