January 18, 2010

Dr. Donna Lee Jones U.S. EPA Mailroom (D243-02) United States Environmental Protection Agency Office of Air Quality Planning and Standards Research Triangle Park, NC 27711

**RE: Response to Request for Information under Secti on 114 of the Clean Air Act, 42 U.S.C.**  **§ 7414, dated December 4, 2009, with regards to the Mercury Cell Chlor-Alkali MACT**  **and background data to support the estimates provide d to USEPA by PPG in a letter**  **dated July 13, 2009**

Dear Dr. Jones:

Attached, please find the first part of PPG’s respo nse to the Section 114 Information Request dated December 4, 2009. As discussed via email on December 17, 2009, and agreed to by you and Joe Karas (PPG Attorney), PPG is providing our response to USEPA’s Information Request in
two parts:

• By January 19, 2010 – PPG to provide the response t o Item #2 of Enclosure 1; and

• By February 18, 2010 – PPG to provide the response to Item #1 of Enclosure 1.

Attachment 1 of this letter contains PPG’s response to Item #2 of the Information Request. Item #2 contains a request for a more comprehensive discussion of the energy costs associated with steam that PPG provided in our July 13, 2009 letter.

Our response to Question #1 will be provided to USE PA by February 18, 2010, as agreed.

Please feel free to contact me at (724) 325-5985 if you have any questions.

Sincerely,

Terry P. Smith Director Technology, Chlor-Alkali & Derivatives PPG Industries, Inc. PPG Industries Inc. 440 College Park Drive Monroeville, PA 15146 Telephone: 724.325.5985 Fax Number: 724.325.5051

Terry P. Smith Director, Technology Chlor-Alkali & Derivatives

### ATTACHMENT 1

**REQUESTED INFORMATION:**

**1. Mercury Emission Estimates** 

(PPG will provide, by February 18, 2010, our respon se to the information requested under Item #1)

**2. Steam Costs**  **EPA’S REQUEST:** In your July 13 letter, you also provide detailed c alculations for the energy costs associated with the steam needed to evaporate membrane cell caustic soda.

Please provide a more comprehensive discussion of ( and references for) the various numbers
used in this calculation.

**PPG RESPONSE:** Following is the information PPG originally provide d in our July 13 th letter regarding steam
costs. PPG’s a dditional explanation and discussion of the numbers used in the calculations are provided in italics:

C. PPG believes that EPA did not consider in its energy cal culation the energy required in the form of steam to evaporate membrane caustic soda to increase its
concentration from 32% to 50% .

The example calculation provided below is intended to represent raising st eam via a natural gas fired boiler, it is generic in nature. Specific cases would need t o be evaluated based on steam source availability and fuel source.

a. Assume double effect evaporation @ 1.8 m lb steam per Ton NaO H

i. Based on the number of pounds of medium-pressure steam required to concentrate caustic soda from 32% to 50%, the following relationships were derived by PPG:
1. Single-effect evaporation = 2.7 m lb steam per Ton NaOH
2. Double-effect evaporation = 1.8 m lb steam per Ton NaOH
3. Triple-effect evaporation = 1.0 m lb steam per Ton NaOH

For this example, double-effect evaporation was used as it provides a middle-ground for capital investment versus steam economy.

Page 1b. 1800 lb steam * 72848 tons Cl2 * 1.128 = 147,910,000 lbs steam

i. Reaction chemistry dictates that 1.128 tons of caustic are produced per each ton of chlorine produced in the chlor-alkali process.

ii. 72,848 tons chlorine per year is the nominal capacity of the PPG Natrium mercury cell facility.

c. (147,900,000 lbs steam * 1150 Btu/lb )/(boiler efficiency of 80%) = 212,621 mmBtu required

i. 1150 Btu/lb is the standard enthalpy of saturated steam made at atmospheric pressure. This number is conservative, as the heat requi red to make medium-pressure steam is slightly higher.

ii. Boiler Efficiency is the ratio of heat given out by the boiler to the heat supplied to the boiler expressed as a %. Steam boiler efficiency var ies by boiler design but a reasonable range for efficiency is 75% to 85%.

Boiler Efficiency = ( heat given out by the boiler / heat supplied to the boiler ) * 100 %

d. Cost @ $5 per mmBtu = $1,063,107 per year

i. $5 per mmBtu of fuel is a conservatively low cost for natural gas, and can be taken as a reasonable fuel cost for coal. Historical data for natural gas can be found on the Energy Information Administration website link:

http://tonto.eia.doe.gov/dnav/ng/hist/n3035us3A.htm

Since natural gas has a heat value of roughly 1000 Btu per cubic foot of gas, the data from the linked chart information is a near approximation of dollars per mmBtu for natural gas. Information from that website for t he five year period from 2004 to 2008 shows that average annual prices for natural gas ranged from a high of $9.60/mmBtu (2008) to a low of $6.50/mmBtu (2004). Therefore, the $5/mmBtu used in our estimate is extremely conservative.

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