Ann McKnight South-End Compressor Station - Executive Summary |
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The accidential release prevention and emergency response policies at this facility: This facility currently complies with Texas Railroad Commission State Wide Rule 61 covering the operation of gasoline plants (NGL) in the state of Texas. By June 21, 1999, we also plan to have the facility in compliance with the requirement of NFPA-58. It is our policy to adhere to all applicable federal, state, and local laws. If an emergency were to occur, it is our policy to notify the Smith County Fire Department and request that they respond to the emergency. Descritpion of facility and regulated substances handled: The Ann McKnight South-End Compressor Station is an electrically powered compressor station located approximately 3-4 miles southwest of Tyler, Texas and is used to transmit natural gas extracted from five natural gas production wells to a gas sales pipeline. The natural gas is conveyed to the facility by underground flowlines. The natural gas is then directed to a refrigeratio n unit where the gas is chilled to below freezing temperatures. Once refrigerated, the gas is directed to a separator where the liquids drop out of the gas and accumulate. The natural gas liquids are then dumped to a pressurized storage vessel until enough natural gas liquids have accumulated inside the vessel to conduct a sales. The natural gas liquids are transferred from the site by use of transport trucks. The worst-case and alternative release scenarios: Our worst-case scenario is the failure of the existing 29,863 gallon pressurized storage vessel when fill to complete capacity, resulting in a vapor cloud explosion. The resulting distance to the endpoint extends offsite, and public receptors are within the distance to the endpoint. No active or passive mitigation scenarios were taken into account for the worst-case scenario. Our alternative release scenario is a break in a 2-inch diameter loading hose leading to a 15-minute release of a flammable mixture (13,659 lbs.) and explosion. Active mitigation was assumed in this scenario by the loading personnel manually shutting off the valve. The resulting distance to the endpoint extends offsite but no public receptors are within the distance to the endpoint. The general accidential release program and chemical-specific prevention steps: This facility complies with EPA's accident prevention rule. The natural gas liquids system is operated in compliance with Texas Railroad Commission Statewide Rule 61 covering the operation gasoline plants in the State of Texas. We are currently in the process of upgrading the facility so that it will meet the standards provided in NFPA-58. This upgrade is anticipated to be completed by June 21, 1999. Five year accident history: We have never had an accident involving a mixture of flammable liquids that caused deaths, injuries, property or environmental damage, evacuations, or shelterings in place. The emergency response program: In the event of an emergency involv ing our pressurized storage vessel and refrigeration unit, it is our policy to notify the Smith County Fire Department and request that they respond to the emergency. We have discussed this policy with the Smith County Fire Marshall; Planned changes to improve safety: A hazard review was performed at the facility on March 24, 1999. based on this review, the following changes are planned to improve safety at the facility: 1) A wind sock shall be installed at the facility to detect wind direction; 2) Remove all dead vegetation from around the perssurized storage vessel: 3) Place a placard on the pressurized vessel to identify vessel contents; 4) Place NFPA diamonds on the storage vessel; 5) Replace loading hose. The hose should be marked "For LP-Gas Service - Working Pressure 350 psi - Manufacturer's Name" and legible along entire length of hose; 6) Provide housing/storage for hose to prevent weathering; 7) Provide protective caps for hoses when not in service to preve nt obstructions inside the hose; 8) Cap all opening and connections on the storage vessel to prevent entry of moisture and foreign objects; 9) Place vent stacks over pressure relief devices to prevent entry of foreign objects and moisture; 10) Place weep holes at base of vent stacks to prevent collection of moisture around relief valves; 11) Pressure test internal relief valves to ensure proper operation: 12) Provide fire extinguishers with protective cabinets near loading area; 13) Provide chock blocks for loading trucks to prevent movement of trucks during loading operations; 14) Paint and label all liquid and vapor flowlines associated with the natural gas liquids system; 15) Replace corroded piping near refrigeration unit; 16) Construct berm around facility to prevent potential liquid spills from traveling off-site. |