Aurora Cooperative - Cairo - 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 east of Cairo, Ne.  is made up of one (1) 30,000 gallon pressurized storage vessel and one loadout riser.  It serves the Hall County area.  This facility is normally unmanned, except during fertilizer season.  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 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, Cairo anhydrous ammonia facility involves the failure of the 30,000 gallon pressurized storage vessel while it contains 85% (maximum allowed capacity) of it's capacity.  The alternative release scenario is based on failure of a three inch transfer hose, assuming that the check valve fails completely and the excess fl 
ow valve in the storage vessel takes two minutes to close.  The bulk propane plant at this facility is located on the same property.  This facility is one of several owned by Aurora Cooperative and is strategically positioned to provide a local retail outlet for propane fuel for home heating, agricultural grain dryer and irrigation operations.  This plant serves primarily Hall County.  This plant consists of one (1) 30,000 gallon pressurized storage vessels.  The worst case scenario for this propane plant is based on the failure of the 30,000 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 endpoint 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, check valve failure, and the release of propane for 2 minutes until the excess flow valve sets and stops the flow.
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