Date: July 21, 2009

To: Jeff Telander, EPA/OAQPS/SPPD

From: Rick Marinshaw, RTI International

Subject: Rationale for Establishing Work Practice Standards for Periodic Brick Kilns

I. Overview of Periodic Kilns

Periodic kilns are batch process units that are used for fir ing brick and structural clay products (BSCP) under a carefully

- controlled environment. The large majority of BSCP are fired in tunnel kilns, which operate continuously and are much more energy

- efficient than periodic kilns when produ cing BSCP of a uniform type , such as standard building bricks . The main advantage of periodic kilns is that they can readily accommodate variations in firing temperature profile s and cycle time s to match the requirements of a wide variety of products. As a result, periodic kilns generally are reserved for specialty products and typically are used only when necessary.

In the BSCP industry, periodic kilns are classified as either beehive kilns or shuttle kilns, but all operate generally the same. A batch o f unfired bricks or shapes is loaded into the kiln, the kiln is sealed, and the burners are ignited and controlled to carefully increase the temperature according to a time

- temperature profile specific to the products being manufactured. Once firing
is co mplete, the temperature in the kiln is reduced, the burners are extinguished, and the fired product is allowed to cool. When the product is at or near ambient temperature, the kiln is opened, and the fired product s are removed.

T he U.S. Environmental Prot ection Agency ( EPA ) conducted an information collection effort in 2008 to update information on the inventory of affected units , hereafter referred to as “the 2008 EPA survey.” Based on the responses to the 2008 EPA survey for the BSCP industry, periodic kiln cycle times range from 35 to 168 hours per cycle, and typically take 48 to 58 hours. These cycle times cover the period beginning when the burners are first ignited and ending when the burners are cut off (Belden, 2008; Blankenbeker, 2008; Krzyzanows ki, 2008; Pence, 2008)

. It may take an additional 8 to 10 hours for the fired product s to cool before they can be removed
from the kiln.2 II. Periodic Kiln Emissions

Based on data from the testing of three periodic BSCP kilns using Method 320 (Fourier

tran sform infrared [FTIR] spectroscopy), emissions of hydrogen fluoride ( HF ) and hydrochloric acid ( HCl ) begin within the first 5 to 10 hours of the firing cycle and continue throughout the firing cycle (Western Environmental, 2003a; Western Environmental, 200 3b; Western Environmental, 200 8 )

. Figures 1 through 3 depict the HF and HCl emission concentrations and kiln temperatures as a function of time for these tests. As indicated in the figures , emissions are highly variable and can experience large spike s at various points throughout the cycle . In addition, it is likely that emissions continue beyond the completion of the firing cycle, as the fired product s cool . For example, Figure 1 shows that HF concentrations in the kiln exhaust can still exceed 100 par ts per million at the end of the firing cycle.3 HF Emissions -- Acme (Bridgeport) Periodic Kiln #3

0 50 100 150 200 25002356810111314161719212324262732333537384041434748

Cumulative Hours from Start of CycleHF concentration (ppm)

0 200 400 600 800 1000 1200 1400 1600 1800 2000Temperature (F) Temperature

HF Concentration

HCl Emissions -- Acme (Bridgeport) Periodic Kiln #3

0.0 10.0 20.0 30.0 40.0 50.0 60.002356810111314161719212324262732333537384041434748

Cumulative Hours from Start of CycleHCl Concentration, ppm

0 200 400 600 800 1000 1200 1400 1600 1800 2000Temperature (F) Temperature

HCl Concentration

Figure 1. HF and HCl Emissions for Periodic Kiln, Acme Brick, Bridgeport, Texas (Western Environmental, 2003b)

.4 HF Emissions -- Acme Milsap Round Kiln

0 50 100 150 200 250 30002357910121415171921232526283032343537394042444950

Cumulative Hours from Start of CycleHF Concentration (ppm)

0 200 400 600 800 1000 1200 1400 1600 1800 2000Temperature (F) Temperature

HF Concentration

HCl Emissions -- Acme Milsap Round Kiln

0 10 20 30 40 50 6002357910121415171921232526283032343537394042444950

Cumulative Hours from Start of CycleHCl Concentration (ppm)

0 200 400 600 800 1000 1200 1400 1600 1800 2000Temperature (F) Temperature

HCl Concentration

Figure 2. HF and HCl Emissions for Periodic Kiln, Acme Brick, Milsap, Texas (Western
Envi ronmental, 2003a)

.5 HF Emissions -- Acme Ft. Smith

0 10 20 30 40 50 60 70 80 9002468101214161819212425272931333537394142444648505254

Cumulative Hours from Start of CycleHF Concentration (ppm)

0 500 1000 1500 2000 2500Temperature (F) Temperature

HF Concentration

HCl Emissions -- Acme Ft. Smith

0 1 2 3 4 5 6 702468101214161819212425272931333537394142444648505254

Cumulative Hours from Start of CycleHCl Concentration (ppm)

0 500 1000 1500 2000 2500Temperature (F) Temperature

HCl Concentration

Figure 3. HF and HCl Emissions for Periodic Kiln, Acme Brick, Ft. Smith, Arkansas (Western Environmental, 200 8 )

.

III. Testing Periodic Kilns for Emissions of HF and HCl

The conventional compliance test requirement for most emission s ources is to test each
source for three 1

- hour test runs. This requirement is based on the assumptions that the source operates continuously and that emissions are relatively constant. However, there generally are
some variations in emissions. For this reason, the source is tested over three separate runs and the results are averaged to generate a number that is representative of typical emissions

.6 Unlike continuous sources, emissions from periodic BSCP kilns can vary significantly
over the course of one cycle. Because of the se variations

, and the fact that emissions begin shortly after the start of the firing cycle and continue beyond the end of the cycle for an undetermined period of time, the conventional compliance test requirement of three 1

- hour te st runs is not an option. Instead, the only way to accurately determine the total emissions from a periodic BSCP kiln cycle is to measure the emissions throughout the entire firing cycle and continuing beyond the completion of the cycle until emission lev els become negligible

. Testing for any less time could result in estimated emissions that either are much higher or much lower than actual emissions, depending on when during the kiln cycle emissions are sampled.

Because of the variations during firing cy cles and variations across the tests represented by Figures 1 to 3, sampling a single kiln cycle might not be adequate for characterizing periodic kiln emissions. For the BSCP industry, that would mean testing each periodic kiln for more than
100 hours in order to determine an emission rate that is representative of normal operating
conditions

. Furthermore, because periodic kilns are used to fire specialty products that may have significantly differently time

- temperature profiles, it may be necessary to t est the same kiln multiple times to characterize emissions from different types of products.

IV. Test Methods

The standard reference methods for measuring emissions of HF and HCl are EPA
Method s 26 and 26A . These methods are reliable and relatively inexpe nsive. However, if emissions are variable and experience large spikes, as appears to be the case for BSCP periodic kilns, breakthrough of HCl can occur. That is, the testing apparatus reaches its capacity for absorbing HCl, and subsequent HCl in the emis sions are not captured. It is not known if breakthrough has occurred until a breakthrough analysis is performed after completion of the test. If it is determined that breakthrough has occurred, retesting is necessary. Another disadvantage to using Metho ds 26 or 26A for testing throughout periodic kiln cycles is the need for additional manpower to operate the sampling trains around the clock and to recover samples.

The alternative to using Methods 26 or 26A is to conduct the tests using FTIR according

to EPA Method 320. With FTIR, HCl breakthrough is not an issue. In addition, FTIR also provides near real

- time emissions data, and the cost for testing by FTIR would not be significantly different than the cost for testing by Methods 26 or 26A throughout an entire cycle. For these reasons, testing by FTIR is the only practical method for accurately measuring HF and HCl emissions from periodic BSCP kilns

.

V. Emission Test Costs

The cost for test ing by FTIR is estimated to be $49,750 for a single 50

- hour kiln cycle (DeWeese, 2009)

. If it were determined that the variations in emissions from cycle to cycle were significant, it might be necessary to test each kiln for two cycles in order to develop a representative emission rate. Doing so would double the test ing costs to almost $100,000. In addition to these costs, additional costs would be incurred for testing the kilns for particulate matter (PM) emissions , which would have to be tested using a manual test method ( e.g. , EPA Methods 5 or 17)

. If testing wer e extended into the cooling period, the costs would be even higher.7 VI. Technical and Economic Feasibility of Numerical Emission Limits for Periodic
Kilns

As stated in s ection 112(h)(1) of the Clean Air Act, work practice standards or other requirements ca n be prescribed in lieu of a numerical emission limit if the Administrator determines that a numerical emission limit is not feasible. Section 112(h)(2)(B) further defines the term “not feasible” in this context to apply when “the application of measureme nt technology to a particular class of sources is not practicable due to technological and economic limitations.”

To evaluate the feasibility of establishing a numerical emission limit for BSCP periodic kilns, the estimated average testing cost for HF and HCl emissions by FTIR for a single 50

- hr kiln cycle (i.e., $49,750 per kiln) was compared to sales data for the 97 periodic kilns located at

BSCP facilities that would be subject to the NESHAP (Walton, 2009). This analysis indicated
the cost

- to

- sales rati o ranged from less than 1 percent to more than 700 percent. Cost

- to

- sales
would be at least 3 percent for 53 of the 97 periodic kilns, and would be at least 10 percent for 48 of the 97 kilns. When compared to typical profits, cost

- to

- profit would be at l east 10 percent for
89 of the 97 periodic kilns, at least 50 percent for 34 of the 97 kilns, and more than 100 percent
for 3 of the kilns. If the additional costs for PM testing, extending the HF/HCl testing into the cooling period, or testing for two cyc les are included, the cost

- to

- sales and cost

- to

- profi t ratios would be even higher.

Based on these findings, it is concluded that it is not feasible to establish numerical emission limits for periodic BSCP kilns because of the technological and economic li mitations
described above. Demonstrating compliance with a numerical emissions limit for periodic kilns is technologically limited to testing procedures that are economically infeasible for the BSCP industry.

VII. References

Belden, B. 2008. “ ICR

- Bric k & Structural Clay Products (Belden Brick) .” E

- mail and attachment from Bradley Belden, Belden Brick Co., to Jeff Telander, EPA/OAQPS/SPPD containing response to Section 114 r equest for the BSCP industry . August 13, 2008.

Blankenbeker, S. 2008. “ EPA B rick Info .” E

- mail and attachment from Steve Blankenbeker, Taylor Clay Products, to Jeff Telander, EPA/OAQPS/SPPD containing response to Section

114 r equest for the BSCP industry . August 14, 2008.

DeWeese, J. 2009. “ Re: Discussion Of Test Methods and C osts For Brick Kilns .” Email and attachment from Jason DeWeese, EPA/EMAD, to Jeff Telander, EPA/SPPD. April 16, 2009.

Krzyzanowski, M. 2008. “ USEPA Information Survey HAP Emission Sources & Controls

- BSCP Industry .” E

- mail and attachments from Mike K rzyzanowski, Glen

- Gery Corp., to Jeff Telander, EPA/OAQPS/SPPD containing response to Section 114 r equest for the BSCP industry . August 13, 2008.

Pence, J. 2008. “ Acme Brick Company

- ICR .” E

- mail and attachments from Jason Pence, Acme Brick Co., to Je ff Telander, EPA/OAQPS/SPPD containing response to Section 114

r equest for the BSCP industry . August 13, 2008.8 Walton, T. 2009. Economic Feasibility of Testing Periodic Brick Kilns . Memorandum from Tom Walton, EPA/ABCG, to Jeff Telander, EPA/SPPD. Jul y 15, 2009.

Western Environmental (Western Environmental Services and Testing, Inc.). 2003a. Acme Brick Company, Milsap, Texas, Emissions Testing : Round Kiln Stack

. February 12 through 14, 2003. File Number 03

- 8004.

Western Environmental (Western Envir onmental Services and Testing, Inc.). 2003b. Acme Brick Company, Bridgeport, Texas, Emissions Testing : Periodic Kiln #3 S tack

. May 21 through 23, 2003. File Number 03

- 8014.

Western Environmental (Western Environmental Services and Testing, Inc.). 200 8

. Acme Brick Company, Fort Smith, Arkansas, Emissions Testing : Kiln 1 Stack

. December 10 through 12,

2003. File Number 03

- 8029. Revised January 21, 2008.