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u I%d ATTACHMENT 18 AMMONIA DISCUSSION Ammonia. Discussion The plant has been designed to minimize the hazards associated with ammonia storage. The ammonia storage tank will be located in a remote part of the plant , away from the plant entrance. Barrier posts surround the tank and extra width is given to the roadway in this area. Please see the Plot Plan enclosed under "Ammonia Storage. " In addition, a loading station is provided complete with safety disconnect and bulkhead. Please see the design sketches enclosed. The impact of an ammonia spill was reviewed using the Complex: Hazardous Air Release Model (CHARM) t- from Radian Corporation. A 50,000 pound spill in a 7. 5 mile an hour- wind indicated that in 15 minutes the concentrations of ammonia would be less than the TLV of 25 ppm. See the enclosed Spill Impact Study. In the unlikely event of an ammonia spill , the Manteca-Lathrop Fire District will immediately be advised. Also, as shown on the enclosed Plot Plan , the ammonia storage tank: is located very close to the gas turbine inlet. In the event of a leak in a low velocity wind , the gas turbine air flow in all likelyhood would :sweep the ammonia into the gas turbine, where it would be combusted or passed on to the SCR where it would be used in the catalysis process. In our Authority to Construct No. AP86- 123 issued June 19, 1987 by the San Joaquin County APCD, General Conditions Paragraph A-6, Public Nuisance states: "No air contaminant shall be released into the atmosphere which causes a public nuisance, " (the odor threshold for ammonia is 46. 8 ppm) . Paragraph A-16 says, "The ammonia slip shall riot exceed 20 ppm, dry at 15% oxygen" . The specification that we have used for the design of the Project limits the ammonia slip to no nore than in ppmv at 15% oxygen , far below the odor threshold. We have utilized California Title 8 and American National Standards for "Safety Requirements for the Storage and Handling of an Anhydrous Ammonia" in designing the amonia injection and control system for the Project. S=ee the enclosed Design Guidelines. We have in our safety manual a section specifically addressing the handling of ammonia and emergency procedures. See the enclosed handling procedures.