Aurora Cooperative - North NH3 & LP Plants - Executive Summary |
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The Aurora Cooperative Elevator Company's accidental release prevention policy involves a unified approach that integrates technologies, procedures, and management practices. The Aurora Cooperative emergency response plan involves the response services available in the community. Aurora Cooperative bulk Anhydrous Ammonia Facilities have been strategically located to provide a local retail facility for this form of affordable nitrogen fertilizer for agriculture. This location, at 605 12th street in Aurora is made up of one 30,000 gallon pressurized storage vessel and two loadout risers. It serves the central Hamilton County area. This facility is normally unmanned, except during fertilizer season, although the adjacent grain elevator and office facilities are normally manned during business hours. The offsite consequence analysis includes consideration of two anhydrous ammonia release scenarios, identified as "worst case release" and "alternative scenario". The first scenario is defined by EPA, which states the the "owner or operator shall assume the the ... Maximum quantity of the largest vessel... is released as a gas over a 10 minute period", due to an unspecified failure. The alternative release scenario is defined as "more likely to occur than the worst case scenario". Atmospheric dispersion modeling has to be performed to determine the distance traveled by the anhydrous ammonia released before it's concentration decreases to a "non-toxic" level. For this purpose, Aurora Cooperative has chosen to use RMP-Comp version 1.05 to determine the distance to the toxic endpoint (.14 mg/l or about 200 ppm) and to determine the population affected by a potential release using maps extracted from Landview 3 software. The worst case release scenario for the Aurora Cooperative - North Anhydrous Ammonia facility involves a failure of the 30,000 gallon pressurized storage vessel while it contains 85% (maximum allowed capacity) of it's capacity. The alternative relea se scenario is based on failure of a three inch transfer hose, assuming that the check valve fails completely and the excess flow valve in the storage vessel takes two minutes to close. The propane bulk plant is located at the corners of E street and 10th street on property that is contiguous to that of the above anhydrous ammonia plant and separated only by Burlingon Northern Railroad tracks. This facility is one of several owned by Aurora Cooperative that are positioned strategically to provide propane as a fuel for home heating, agricultural grain drying and irrigation operations. This Plant serves primarily Hamilton County Nebraska. The worst case scenario for this propane plant is based on a failure of the 18,000 gallon pressurized storage vessel while it contains it's maximum allowable capacity of 85%. Aurora Cooperative has chosen RMP-Comp version 1.05 to determine the over-pressure endpoint (1 psi) from the vapor cloud explosion that could occur in this scenario. The Alte rnative release scenario is based on the failure of a three inch transfer hose, check valve failure, and the release of propane for 2 minutes until the excess flow valve sets to stop the flow. |