Document 2je20yOaK0Ra525kL4p3Jag9L

AR226-2231 December 10,2001 CERTIFIED MAIL RETURN RECEIPT REQUESTED Mr. John Benedict. Acting Director Division of Air Quality WV Department o f Environmental Protection 7012 MacCorkle Avenue Charleston, WV 25304-2943 RE: Regulation 13 permit R13-815D Dear Mr. Benedict: With this letter DuPont hereby provides information pertinent to the impact o f changing the diameter of permitted emission point T6IFCE and requests expeditious approval to make this change which is necessary in order to operate the process as is otherwise described in the permit.. In the process o f starting operation of the new dryer, source ID T61V, DuPont engineers have discovered that the existing scrubber and exhaust system cause excessive back pressure when the two existing dryers, T6IE and T6IF, are also operating. This causes an electronic interlock to bypass T6IE and T6IF from the scrubber as allowed per the permit. The engineers have determined that the back pressure can be sufficiently reduced to allow normal operation of the scrubber if the internal diameter o f vent T6IFCE is increased from 18 inches to 22 inches. The requested change will have no impact on the production rate or mass emission rate for the permitted process. The maximum hourly emission rate for particulate emissions less than 10 microns will still be no greater than 11.5 pounds per hour as allowed per permit R 13-815D. The annual emission rate for this vent will still be no greater than 31,610 pounds per year as proposed for permit R13-815E, or as limited by the restriction to not exceed year 2000 emissions on a rolling 12-month basis per consent order R13-E-20O1-34, or for the Washington Works facility to not exceed year 2000 emissions on a calendar year basis per consent order GWR-2001-019. The requested change will decrease the exit vent velocity for this source by 33%, from 60.4 meters per second (M/s) to 40.4 M/s. The results of ISCST modeling indicate the concentration at the maximum receptor will increase by 12.5%, from 2.08 micrograms per cubic meter (ug/m3) to 2.34 ug/m3. Note that rates used in the modeling run were based on year 2000 actual emissions for all related fluoropolymer sources. Should you have any questions or concerns regarding the actions described in this letter or any related matter, please contact me at 304-863-4271. Very truly yours, R. L. Ritchey Sr. Environmental Control Consultant Washington Works CC: Mr. Jesse Adkins E ID 669458 Assistant Chief, Enforcement WVDAQ Mr. Jesse Hanshaw Engineer, Permitting WVDAQ E ID 669459