Mulberry Cogeneration Facility - Executive Summary |
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RMP Executive Summary for Mulberry Cogeneration Facility Facility Description and Regulated Substances Handled The Mulberry Cogeneration Facility (Mulberry Cogen) is an independent cogeneration power plant owned by Polk Power Partners, L.P. (PPP) and operated by CSW Energy, Inc. (CSW). The power and steam generated for sale is produced from a single natural gas turbine in combination with a single steam turbine. Mulberry Cogen has two RMP regulated substances at the facility, anhydrous ammonia and chlorine. The ammonia is used in a closed loop system for cooling the inlet air to the combustion turbine. Total quantity in the entire system of vessels and piping is approximately 49,500 lbs. It is located adjacent to the combustion turbine and its evaporative condenser (Inlet Cooling Tower). The chlorine is stored in three one-ton cylinders located near the two cooling towers. The chlorine is used for microbiological control in the cooling tower waters. Whereas most of the chl orine is absorbed and consumed by the water, a low (0.3 ppm free Cl2) residual is maintained in the bulk water. Five-Year Accident History Mulberry Cogen has been in commercial operation since August 10, 1994 and has had no reportable, accidental releases of chlorine or ammonia since that time. General Accidental Release Prevention Program and Chemical-Specific Prevention Steps Mulberry Cogen Facility complies with all applicable federal, state, and local statues governing the storage and use of all chemicals. This includes compliance with OSHA's Process Safety Management Program, EPA's Risk Management Program, and Hazardous Chemical reporting under SARA Title III. Since communication and knowledge are important preventative measures in a safety program, a Right-To-Know center in the Control Room provides safety information to all employees, contractors, and visitors to the site. Contained in the center are Material Safety Data Sheets (MSDS), the Emergency Response Guidebook, Th e Pocket Guide to Chemical Hazards, and Keller's Official OSHA Safety Handbook, Health Effects of Ammonia, and Control of Natural Gas In Emergency. The Mulberry Cogeneration Facility was constructed with many safeguards for chemical handling and usage. The hazardous liquid chemicals on site, sulfuric acid and caustic, are stored in tanks surrounded by secondary containment. The pumps used to deliver the chemicals to the various processes are also inside the containment dike. Chemical piping is double-piped where appropriate. UV resistant tubing has been employed for delivery of chlorine and other chemicals where tubing is exposed to sunlight. Accidental Release Prevention and Emergency Response Policies CSW Energy - Mulberry Operations is committed to maintaining a safe working environment while using chemicals necessary for power production and its auxiliary processes. CSW Energy maintains a Safety Manual and supplements it with written manuals from equipment vendors and chem ical suppliers. Personnel protective equipment is made available to all employees and training is given annually to demonstrate the proper use of the safety equipment provided. In addition specific training is given each year on regulated substances; ammonia, chlorine, mercury, ferrous sulfate, caustic, and sulfuric acid. The MSDS for new chemicals are routed for all personnel to review. An Emergency Action Plan (EAP) was written and implemented beginning with construction of the plant and continuing on through present day plant operations. Features of the EAP include plant communications and alarm systems, evacuation procedures and routes, fire and rescue equipment, general fire protection guidelines, emergency notification procedures and emergency response procedures. The EAP also includes a separate section on ammonia and chlorine safety and ammonia and chlorine leak procedures. Employees are trained to be familiar with the contents of the EAP and several copies of the EAP are readily available in the case of an emergency at the facility. Worst-Case Release Scenario and the Alternative Release Scenario CSW - Mulberry Operations chose to model the worst-case release and alternative release scenarios for ammonia with a model commonly used by the ammonia industry known as DEGADIS (tm). For the worst-case and alternative release scenarios for chlorine we used the EPA's RMP Comp (tm) model. Ammonia The worst case scenario is the rupture in a vessel with the loss of the entire system contents, 49,500 pounds. The system is located near the Main Cooling Tower, which may have some drafting affect as passive mitigation. However since it can not be defined, no credit was taken in the modeling for any passive mitigation. An alternative release scenario, more likely to occur, is the release of only the portion of the ammonia contained in the liquid receiver. This is approximately 25,000 pounds. A portion of this ammonia would spill in the form of a liquid an d would subsequently be evaporated. The remainder would be released as a gas. Active mitigation which would help contain the release includes manual water hoses for use as a water curtain and isolation valves to minimize the quantity. Similar to the worst case scenario, no credit was taken for any passive or active mitigation. The probability of either release is remote. The ammonia vessels are inside a controlled area from the public. Any contractors working in the area are advised of the ammonia vessels and care is taken to prevent vehicles or forklifts from approaching the area unless absolutely necessary. The system is also designed with safety release valves to protect from over-pressurization. All employees receive training on the ammonia system, it's operation and safety features. Chlorine The worst-case scenario is the rupture of a one ton cylinder of chlorine Since the chlorine storage is located in close proximity to a forced draft cooling tower it is assumed that the tower would act to have some passive mitigating affect on a chlorine release. Chlorine gas would be drawn into the tower and quenched with the falling water in a countercurrent fashion. Although this mitigation may be affective, no credit was taken for the absorption of chlorine in the cooling tower when modeling the toxic endpoint of the release. The alternative release scenario is the release of the entire contents of a one-ton cylinder through a 1" opening, a fault in a fusible plug. Again some passive mitigation could occur due to the proximity of the cooling towers. However no credit was taken for the passive mitigation in the modeling. Active mitigation during the alternative release scenario includes the use of a chlorine cylinder leak repair kit. A cylinder leak kit is staged in the area of the cylinders and all employees are trained in the use of the repair kit. Again, although this mitigation action is possible during a chlorine release, no reduction in time or am ount was considered when modeling the release. Although this summary has outlined two potentially large releases of chlorine gas, the probability of a release of this nature happening is remote. The cylinders are located in an area which is protected from vehicle traffic and industrial activity. The overhead hoist used for loading and unloading cylinders on or off the delivery truck is always stored resting on the ground beside the cylinders. This is to prevent any possible damage due to a falling hoist, while the cylinders are unattended. The leak washer around the service valve is replaced with each new cylinder placed in use. Emergency Response Program CSW Energy - Mulberry Operations reports for Mulberry Cogen the hazardous chemicals on site, amount and location, to both the Local Emergency Planning Committee and the local fire department as required by SARA Title III, Section 313. The Tier Two Reports submitted are maintained in an active file system in the response vehicl e and therefore are readily available to emergency responders to the facility. Facility personnel are trained how to respond to leaks, including notification procedures. When possible, any release is first handled by plant personnel. In the event of a major release, the notification plan in the facility's Emergency Action Plan is implemented. Planned Changes to Improve Safety CSW Energy - Mulberry Operations is always looking for ways to improve safety for our employees and those who work around us. Trade magazines, conferences with other utility industry personnel and discussions with chemical and equipment vendors are some of the ways facility personnel discover new and improved ways of doing business. We also subscribe to a safety news update publication and attend OSHA seminars locally. 06/01/99 |