Aurora Cooperative - Marquette - 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 203 Railroad in Marquette is made up of two (2) 11,000 gallon and one (1) 18,000 gallon pressurized storage vessel and two loadout risers. It serves the northern 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 scen ario". The first scenario is defined by EPA, which states that the "owner or operator shall assume that 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 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 Marquette anhydrous ammonia facility involves the failure of the 18,000 gallon pressurized storage vessel while it contains 85% (maximum allowed capacity) of it's capac ity. The alternative release scenario is based on failure of a three inch transfer hose, assuming complete failure of the in-line check valve and that the excess flow valve in the storage vessel takes two minutes to close. The bulk propane plant at this facility is located on property that is adjacent to and contiguous with that of the above anhydrous ammonia plant and is seperated only by Burlington Northern Railroad tracks. This facility is one of several owned by Aurora Cooperative and is positioned to provide a local retail outlet for propane fuel for home heating, agricultural grain dryer and irrigation operations. This plant serves primarily northern Hamilton County. This plant consists of two (2) 6,000 pressurized storage vessels. The worst case scenario for this propane plant is based on the failure of one of the 6,000 gallon vessels while it contains it's maximum allow capacity of 85%. Aurora Cooperative has chosed RMP-Comp Version 1.05 to determine the over-pressure en dpoint (1 psi) from the vapor cloud explosion that could occur in this scenario. The Alternative release scenario is based on the failure of a three inch transfer hose, failure of the in-line check valve, and the release of propane for 2 minutes until the excess flow valve sets and stops the flow. |