ACE Cogeneration Facility - Executive Summary |
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INTRODUCTION ACE Cogeneration Company (ACE) is required to comply with Section 112(r) of the Clean Air Act, which requires facilities with acutely hazardous materials or flammable materials over the regulatory threshold to prepare a Risk Management Plan (RMP). ACE stores up to 10,320 gallons (60,800 pounds) of anhydrous ammonia, an acutely hazardous material on site at any given time. This amount is over the 10,000-pound threshold. ACE originally prepared a Risk Management and Prevention Program (RMPP) in 1991 pursuant to California regulations and has complied with OSHA's Process Safety Management (PSM) program. Both of these programs are similar in most respects to the Clean Air Act RMP program. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY POLICIES ACE has a commitment to environmental compliance. In addition to environmental, health and safety (EH&S) policies and principles, ACE has also instituted a compliance assurance plan (CAP). The CAP is a living compliance management document developed from the Federal Sentencing Guidelines and ISO 140001 elements. Through a system of schedules, monitoring regulatory requirements, audits, training, incentive/discipline programs, and record keeping, ACE ensures compliance and continuous improvement. The ACE Cogeneration Company Environmental Policy Statement: ACE Cogeneration Company's Environmental Policy is to conduct business in a manner that is lawful, compatible with the environment and conductive to the health and safety of employees, facilities and the community. ACE Cogeneration Company Health and Safety Policy Statement: The ACE Cogeneration Company's Health and Safety Policy is to conduct business in a manner that is lawful and promotes the health and safety of employees, contractors, visitors and the community. Environmental, Health, and Safety Principles: ACE Cogeneration Company will conduct business consistent with the EH&S Policy and the following EH&S Principles: 7 Activities will be conducte d in compliance with applicable laws, regulations, industry standards and guidelines. 7 Activities will be managed to protect people and property and to control ACE Cogeneration Company's liabilities. 7 ACE Cogeneration Company's Management Committee and secondary employees will be individually and collectively accountable for the execution of the EH&S Policy. 7 EH&S goals will be achieved through the prudent use of resources, and through communication, education, proactive management, assessment and action. Relative to compliance with the RMP program, ACE has a ten-year history of successful compliance with the California Risk Management Prevention Plan (RMPP) and the OSHA PSM program. Successful compliance has been a result of adherence to the above programs and future compliance is anticipated based on this formula. FACILITY AND REGULATED SUBSTANCES ACE owns a 118-megawatt (gross), coal-fired, circulating fluidized bed, cogeneration facility, referred to as the ACE Cogeneration Facility, in northwestern San Bernardino County. ACE began operation in 1990. A/C Power-ACE Operations personnel, under an Operation and Maintenance Agreement, perform the day-to-day operation. ACE provides steam for IMC Chemical (IMCC) Company. Ammonia is used to reduce the nitrogen oxide emissions, which improves air quality. The emissions control operations include storage and handling up to 10,320 of anhydrous ammonia, a substance that the Environmental Protection Agency (EPA) has identified as an acutely hazardous material. The Federal and State of California governments have established a program for reducing the hazards associated with the storage and handling of such materials. The program was initiated by the Clean Air Act Amendments of 1990, Title III, Section 112(r) and codified in 40CFR Part 68. The California Accidental Release Program (CalARP) pursuant to Sections 25531 through 25543.3 of the Health and Safety Code has additional regulations. As part of this program, ACE is required to prepare a Risk Management Plan (RMP) for its anhydrous ammonia storage and handling facilities. In an RMP, a facility reviews its processes, equipment and procedures in order to identify steps that could reduce the likelihood or consequences of a release of an acutely hazardous material. ACE requested the assistance of AVES, an affiliate of ATC Associates, Inc. (AVES) in preparing the RMP. THE WORST-CASE RELEASE SCENARIO AND THE ALTERNATE RELEASE SCENARIO An RMP must consider the results of the following: 1. A hazard and operability study that identifies the hazards associated with handling an AHM due to operating error, equipment failure, and external events that may present a risk of an accident an AHM. 2. An off-site consequence analysis that assumes pessimistic air dispersion parameters, and other adverse environmental conditions for the worst case scenario and an alternative release scenario. A hazard analysis review was compl eted at the ACE on April 13, 1999 for the RMP process. The review covered the hazard analysis conducted as a requirement of the California RMPP program and the Process Hazard Assessment (PHA) conducted as a requirement of the OSHA Process Safety Management (PSM) program. Both previous studies were conducted using the "what if" methodology. Both studies were re-examined and a site walk was completed as part of the hazard analysis review. The basic events, which could lead to potential off-site impacts, are corrosion failure, external event, and on-site accidents. The worse case and alternate release scenarios were developed from these studies. The off-site consequence analysis (OCA) requires analysis of two release scenarios: worst-case and an alternate release scenario. The worst-case release scenario, according to the RMP Requirements, must consider a release that empties the content of the ammonia system in a ten-minute period. This scenario does not take into account whether or not the release is probable. The alternative release scenario is designed to investigate the worst-case release that could happen within the lifetime of the facility. This scenario takes into account the combination of frequency and severity. The maximum capacity of the ammonia storage tank is 12,000 gallons. Written operating procedures and a high-level alarm prevent more than 10,320 gallons from being present in the 12,000-gallon tank, or 86 percent level by volume. Both the worst-case and alternate release scenarios were completed according to the EPA's OCA Guidance with RMP*Comp. RMP*Comp is an electronic air dispersion modeling tool used to perform the off-site consequence analysis required under the Risk Management Program rule published by the Environmental Protection Agency on July 20, 1996, which implements Section 112(r) of the Clean Air Act. Both the OCA Guidance and RMP*Comp are available to the public and can be downloaded from the EPA's Chemical Emergency Prepar edness and Prevention Office web site at http://www.epa.gov/ceppo. Worst Case Release Scenario Catastrophic release of ammonia from the storage tank. This scenario could result from a number of potential "accidents". While none of the accidents leading to this release were of high frequency, it was judged the most credible worst case. Alternative Release Scenario Release of the entire ammonia contents of the tank through an ammonia line pipe sheared near the tank. This scenario corresponds to a high flow scenario. EVALUATION OF RISK The most significant impact from an ammonia release would occur at the ACE Cogeneration Facility. Anyone working outside within a few hundred yards of the release would be exposed to the highest concentrations for the worst-case scenario. Personnel located inside buildings would be at less risk, since ammonia would enter these areas at a rate dependent on building ventilation rates. The next most vulnerable area of impact would be the IMCC f acility located to the south and east of the facility. Again, those outside working would be most vulnerable, while those located indoors would be protected from the highest concentrations. The worst case scenario off-site consequences extended the vulnerability zone to 4.5 kilometers from the facility. The worst case scenario would affect 2,740 residential receptors in Searles Valley at a level above the CAAA Title III endpoint level of 140 mg/m3 (based on estimate - specific data for Trona was not listed in 1990 U.S. Census data). In addition, there would be a high school (180 students, 20 faculty), an elementary school (227 students, 20 faculty), and a pre-school (20 children, 2 faculty) in Trona that would be affected. No day care centers or hospitals were listed within the vulnerability zone. In addition, there were no official desert tortoise or other protected species habitat boundaries located within the vulnerability zone. An examination of meteorological conditions i n the area indicates that the type of stable conditions used in this analysis can occur fairly often in the area. For the alternative release scenario, the Trona schools would not be exposed to ammonia concentrations above the EPA endpoint. Approximately 25 residential receptors and one commercial receptor (a chemical facility) would be affected. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL-SPECIFIC PREVENTION STEPS ACE complies with both the Federal/State RMP requirements, and OSHA's Process Safety Management (PSM) Program (Section 1910.119 of Title 29 of CFR or Section 5189 of Title 8 of CCR). Many parts of the PSM standards have been incorporated into the RMP regulations. ACE has employed engineering and administrative controls to reduce frequency and severity of ammonia releases. Engineering and Administrative Controls Engineering controls include equipment compatible with anhydrous ammonia, ammonia sensors, relief valves, check valves, manual and automati c shutoffs, interlocks, alarms and procedures, emergency air supply, emergency power, and grounding equipment. Mitigation systems include dikes, a deluge system and a canopy. Administrative controls include: health and safety and process training for all employees, contractors and visitors, procedures for different aspects of operation, record keeping, proper installation of equipment, regular inspection, ammonia truck off-loading procedures, storage tank/system operation procedures, ammonia injection procedures, repair and maintenance for all equipment using anhydrous ammonia. Plant personnel supervise the delivery and off-loading of ammonia. THE FIVE-YEAR ACCIDENT HISTORY There have been three incidents at ACE. 1. On April 29, 1992, relief valves on the ammonia storage tank lifted due to a high tank temperature. It was speculated that the vaporizer and solar heating caused the high temperature. This was corrected by re- calibration of the system. 2. On July 29, 1992 , the fill line relief valve discharged a slight amount of ammonia vapor to the surrounding area. It was speculated that solar heating and ammonia left in the fill line produced the release. The vendor was contacted to ensure the unloading procedure includes evacuation of the lines before they are disconnected. 3. On October, 3, 1995, the relief vent of the fill line was venting. A failure of a fill line isolation valve allowed the fill line to back fill. Ambient heat caused the expansion of the ammonia, which caused the relief valve to lift. This was corrected by replacing the isolation valves and installing a manual deluge station. THE EMERGENCY RESPONSE PROGRAM ACE has coordinated with the San Bernardino County Fire Department, the local emergency responders. ACE personnel are trained to report all releases to local emergency responders and to follow instructions from the responders. PLANNED CHANGES TO IMPROVE SAFETY As a result of the proce ss hazard analysis the following modifications were suggested at the HazOp in April of 1999: 7 Add posts in front of the loading station to protect it from vehicle traffic. The following changes will be completed by December 2000. 7 Additional posts added to protect the loading station. |