Greenleaf 2 Power Plant - Executive Summary |
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Title III of the U.S. Clean Air Act (CAA), Amendments of 1990, requires that certain facilities prepare and submit a Risk Management Plan (RMP). The Greenleaf 2 Power Plant, located in Sutter County, California, is subjed to that requirement. The State of California has responded to the federal requirements with development of its own regulations in CCR Title 19, Division 2, Chapter 4.5. The regulations set forth a program known as the California Accidental Release Prevention Program or CalARP. The CalARP reqirements closely parallel the federal requirements set forth in 40 CFR Part 68. This RMP has been developed according to the CalARP regulations. Many of the reqiremts under CalARP are the same as those mandeated under the Occupational Safety and Health Administration's (OSHA's) Process Management (psm) program, which is already in effect at Greenleaf 2. RELEASE AND EMERGENCY RESPONSE POLICIES The chemical process at Greenleaf 2 covered under the CalARP program is the use of anhydrous ammonia for reduction of nitrogen oxides in the exhaust from the Greenleaf 2 Power Plant. Greenleaf 2's policy is to prevent unplanned or accidental releases of anhydrous ammonia in any quantity. Previously developed environmental and injury and illness prevention policies reinforce this release policy and, when implemented, act to prevent releases. The environmental and injury and illness prevention policies are contained in Appendix A. Greenleaf 2's policy prohibits employees from responding to emergencies such as catastrophic releases of anhydrous ammonia. However, employees are allowed to respond to small or incidental releases such as minor leaks or spills. THE FACILITY AND REGULATED SUBSTANCE Greenleaf 2 is a nominal 49.2 megawatt (MW) cogeneration facility, which uses a Stewart and Stevenson package containing a General Electric LM5000 gas turbine and a Brush generator to produce electrical power. The adjacent Sunsweet fruit processing facility purchases ste am created by the facility. Greenleaf 2 employs a total of 10 persons to run and maintain the power plant. Anhydrous ammonia is used to control the nitogen oxide (NOx) emissions from the power plant's exhaust stack to meet the facility's permitted air emissions limits for NOx. Ammonia vapor is injected into the plant stack's Selective Catalytic Reduciton (SCR) system, supplied by Johnson-Matthey Company. Anhydrous ammonia suppliers deliver ammonia in tank trucks to refill the Greenleaf 2 storage tank. The ammonia is delilvered as a liquid under pressure; and the 12,000-gallon storage tank is filled to a maximum level of 9,600 gallons. Ammonia vapor is drawn from the tank, diluted with ambient air, and injected into the SCR system via an injection grid. An automatic control and monitoring system regulates the vapor flow. The entire ammonia storage, vaporization, and injection cycle is relatively simple and designed and operated per standard industry practice. The plant has an em ergency response plan for appropriately responding to any ammonia vapor releases. WORST-CASE AND ALTERNATIVE RELEASE SCENARIOS The worst-case anhydrous ammonia release scenario assumed that 9,600 gallons (60,000 lbs) of ammonia were released from the storage tank at the rate of 6,000 lb/min. so that all of the contents escaped from the tank in 10 minutes. Meteorological conditions at the time of the release were assumed to include a wind speed of 1.5 meters/sec, and ambient temperature of 25 degrees C, and atmospheric stability class F, and an urban topography. The results of the analysis using U.S. EPA's RMP*Comp simulation model were a distance (radius) of 2.8 miles to the toxic endpoint concentration of 0.14 mg/L, or approximately 200 ppm. Approximately 40,000 people would be included within the 2.8 mile radius and the radius would include schools, hospitals, residences, commercial and industrial facilities. The alternative release scenario assumed that a leak in the delivery hose from the truck to the storage tank would release 3 gallons in one minute. Meteorological conditions at the time of the release were assumed to include a wind speed of 3 meters/sec, an ambient temperature of 25 degrees C, an atmospheric stability class D, and an urban topography. The results of the analysis using U.S. EPA's RMP*Comp simulation model were a distance (radius) of less than 0.1 mile to the toxic endpoint concentration of 0.14 mg/L, or approximately 200 ppm. The actual endpoint distance that was estimated (not using the model) was 0.01 mile or approximately 53 feet. The toxic endpoint would therefore remain within the Greenleaf 2 site boundary and only Greeleaf 2 employees would be potentially affected. RELEASE PREVENTION PROGRAM The Greenleaf 2 release prevention program addresses a number of areas to prevent releases of ammonia. These areas include a process hazard analysis (PHA), operating procedures, training, mechanical integrity, management of change, pre-s tartup review, compliance audits, incident investigations, employee participation, hot work permits, and procedures for the procurement and use of contractors. A key item of the RMP prevention program is the PHA. This analysis was performed for the anhydrous ammonia system by a team of knowledgeable persons. The team used a "what-if" approach, which determined what events could possibly cause an accidental release of ammonia. The team then assigned a probability to the occurrence of each event. The team identified several actions that should be cosidered by Greenleaf 2 to reduce the probability of an accidental release of ammonia. FIVE-YEAR ACCIDENT HISTORY Since the start up of the facility in 1989, there have been no accidents or catastrophic releases involving anhydrous ammonia. EMERGENCY RESPONSE PROGRAM Greenleaf 2 has an emergency response plan in place. This plan incorporates all CalARP requirements for an RMP emergency response program. Key elements of the program are procedures for informing the public and local emergency response agencies in the event of a release, steps to be taken for medical first-aid treatment, and mitigation measures following an accidental release of ammonia. Also included in the Greenleaf 2 emergency response program are procedures for the use of emergency response equipment; training for Greenleaf 2 employees in the Incident Command System; and procedures for reviewing, updating, and informing Greenleaf 2 employees of changes in the emergency response plan. PLANNED SAFETY CHANGES During the process hazard assessment, several recommendations were made for the improvement of safety at Greenleaf 2. Recommendations now being implemented include the addition of chains between traffic guards surrounding the ammonia storage tank, the placement of traffic cones around the ammonia delivery truck while unloading ammonia, and the use of personal protecitve equipment for employees involved in opening and closing vlaves. In ad dition, Greenleaf 2 management will verify unloading procedures with ammonia vendors and confirm that vendor procedures ensure that chemicals other than ammonia re not inadvertently deliverd to the Greenleaf 2 storage tank. CONCLUSION Greenleaf 2 has complied with the RMP requirements and is committed to reviewing and enhancing the plant's emergency preparedness program periodically as appropriate and in compliance with the federal and state requirements. The RMP program documents are complete and accessible to all interested persons at all times. The Greenleaf 2 RMP program is proactive, meets the CalARP requirements, and confirms Greenleaf 2's commitment to its environmental and safety policies, which are designed to protect the offsite public and environment, employees, and contractors. The RMP was prepared by Greenleaf 2 with assistance from CH2M HILL. |