Houston Central Gas Plant - Executive Summary |
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1.0 Houston Central Gas Plant Risk Management Plan: Executive Summary ACCIDENTAL RELEASE PREVENTION AND RESPONSE POLICIES The Houston Central Gas Plant has a long-standing commitment to worker and public safety. This commitment is demonstrated by the resources invested in accident prevention, such as training personnel and considering safety in the design, installation, operation, and maintenance of facility's processes. The Shell Western E&P Inc. (SWEPI) policy is to implement reasonable controls to prevent foreseeable releases of substances. However, if a release does occur, trained personnel will respond to, control, and contain the release. DESCRIPTION OF THE STATIONARY SOURCE AND REGULATED SUBSTANCES SWEPI operates the Houston Central Gas Plant located in Colorado County, Texas. Texas Gas Plants, L.P. is the owner of the facility. The gas plant receives produced natural gas via pipeline. Residue gas is removed from the plant by pipeline. The hydrocarbon liquids are fraction ated at the Houston Central Gas Plant and the fractionated products are shipped out via pipeline. The Houston Central Gas Plant was evaluated to determine if any regulated flammable or toxic substances exceeded the threshold quantity. Based on process knowledge, SWEPI identified the regulated substances and quantities kept on site. Listed flammable substances which are stored above threshold quantities at the Houston Central Gas Plant are distillate, propane, natural gasoline, rich/lean oil, n-butane, raw make, isobutane, natural gas and sponge oil. However, SWEPI has determined that rich/lean oil and sponge oil have an National Fire Protection Association (NFPA) flammability hazard rating of 1, which exempts these mixtures from threshold determination. Based on worst-case analysis, the distances to the endpoints do not exceed the distance to public receptors. In addition, the Houston Central Gas Plant has not had an accidental release in the past five years and emergency respons e procedures have been coordinated with the Columbus Volunteer Fire Department and the Sheriff's Office. Therefore, the Houston Central Gas Plant is classified as a Program 1 process under the ARP program. OFF-SITE CONSEQUENCE ANALYSIS RESULTS Flammable Substances - Worst-Case Scenario The endpoint for worst-case release of flammable substances is 1 psi overpressure (i.e., 15.7 psia), resulting from a vapor cloud explosion. The ARP Program requirement for flammables assumes an instantaneous release and vapor cloud explosion. A yield factor of 10 percent of the available energy released in the explosion shall be used to determine the distance to the explosion endpoint. Since the worst-case release scenario for a flammable substance is based on the assumption that the entire quantity of the substance in a vessel forms a vapor cloud, passive mitigation systems are not applicable. Distillate is the worst-case flammable release with a 0.97-mile distance to the endpoint. Flammable Sub stances - Alternative-Case Scenario The Houston Central Gas Plant is classified as a Program 1 process under the ARP program. Therefore, analysis of an alternative release scenario for flammable substances is not required. Toxic Substances The Houston Central Gas Plant does not have any toxic substances above the threshold quantity; therefore, analysis of worst-case and alternative-case release scenarios for toxic substances is not required. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM Based on the criteria in 40 CFR 68.10, the distance to the specified endpoint for the worst-case accidental release scenario for the following processes is less than the distance to the nearest public receptor: distillate, natural gasoline, n-butane, isobutane, propane, raw make and natural gas. Within the past five years, the processes have had no accidental releases that caused off-site impacts as defined in the risk management program rule (40 CFR 68.10(b)(1)). No additional measures are nece ssary to prevent off-site impacts from accidental releases. In the event of fire, explosion, or a release of a regulated substance from the processes, entry within the distance to the specified endpoints may pose a danger to public emergency responders. Therefore, public emergency responders should not enter this area except as arranged with the emergency contact indicated in the Risk Management Plan. The undersigned certifies that, to the best of my knowledge, information, and belief, formed after reasonable inquiry, the information submitted is true, accurate, and complete. EMERGENCY RESPONSE PROGRAM INFORMATION The overall emergency response program for the Houston Central Gas Plant is coordinated with the Columbus Volunteer Fire Department and the Sheriff's Office. This coordination includes periodic meetings of the Houston Central Gas Plant personnel, fire department and Sheriff's Office to discuss needs and concerns in the event of an incident at the plant. The Houston Cent ral Gas Plant has around-the-clock communications capability with the fire department and Sheriff's Office, which has the ability to communicate to all state, federal and county agencies as to needed equipment (i.e., firefighting equipment, manpower, ambulances, hospitals, law enforcement, and HAZMAT operations). This provides a means of notifying the public of an incident, if necessary, as well as facilitating quick response to an incident. In addition to an annual meeting with the fire department and Sheriff's Office, the Houston Central Gas Plant conducts periodic emergency drills that involve the Columbus Volunteer Fire Department, Sheriff's Office and emergency response organizations, and the gas plant provides annual refresher training to local emergency responders regarding the hazards of regulated substances in the gas plant. |