Aux Sable Liquid Products LP - Executive Summary |
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Executive Summary Aux Sable Liquid Products LP, Channahon, Illinois The Aux Sable Liquid Products LP plant is located at 6155 East US Route 6, Channahon, Illinois, in Aux Sable Township, Grundy County, approximately 50 miles southwest of downtown Chicago in the NW ? of Section 22, T34N, R8, E of 3rd P.M. in Aux Sable Township, Grundy County, Illinois. The plant site is approximately 150 acres in size. (Note: The fenced area is less.) The Aux Sable Liquid Products LP. facility is a natural gas liquids processing plant. The facility produces quantities of propane, butane, iso-butane, and a pentanes plus liquid (composed of butane, iso-butane, pentane iso-pentane, n-hexane, and heptane) in excess of the United States Environmental Protection Agency's Risk Management Plan (RMP) threshold planning quantities for flammable substances. The facility is considered a RMP program 3 facility. The natural gas liquids plant removes commercial grade ethane, propane, iso-butane, normal butane a nd a pentane+ product (condensate) from the natural gas stream being transported by Alliance Pipeline L.P. Processes include: extraction and demethanization; ethane recovery; depropanization; debutanization and butane splitting. Other associated equipment includes compression equipment, process heaters, product storage for propane, butane, iso-butane, and a pentanes plus liquid. The prevention program based on this regulation includes the following: Employee Participation; Process Safety Information; Process Hazardous Analysis; Operating Procedures; Training; Contractor Safety; Contractor and Visitor Orientation; Pre-Job Startup Review; Mechanical Integrity; Code of Safe Practices; Management of Change; Incident Investigation; Emergency Planning and Response; and Compliance Audits. Mechanical Integrity includes ultrasonic testing of vessels and piping, material specifications, hydrotesting, and other applicable testing/treating procedures. Aux Sable Liquid Products LP maintains an emergency response plan in compliance with local emergency response agencies. The worst case release scenario is a release from a 30,000-barrel propane storage pressure sphere. The quantity of propane that could be released and contribute to the worst case scenario is estimated at 5,118,530 pounds (1,260,000 gallons), resulting in a vapor cloud explosion. The 1-psia overpressure could extend out to a distance of 1.39 miles from the pressure sphere. The distance was calculated using equation C-1 from the USEPA's RMP Offsite Consequence Analysis Guidance based on liquefied propane stored under pressure. The alternative release scenario is a vapor cloud explosion, which results in a 1-psia overpressure at a distance of 0.10 miles. This does not result in any off property impacts. The distance was calculated using the TNT equivalency method and assuming 3% of the flammable vapor is assumed to participate in the explosion. The distance to a 1-psia overpressure was also calculated using the Multi Energy method of explosion overpressure calculation. The Multi Energy method is considered more accurate for hydrocarbon vapor cloud explosions. Using this method, the distance to a 1-psia overpressure was 0.04 miles (no off property impacts). The alternative release scenario assumes that the plant by-pass stack vents for 10 seconds. The Aux Sable Liquid Products LP facility in a new state-of-the-art facility with the highest level of safety designed into the plant. As a new plant, it has had zero incidents in the past five years. |