Great Plains Synfuels Plant - Executive Summary |
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1. Accidental Release Prevention and Emergency Response Policies The Dakota Gasification Company (DGC) Great Plains Synfuels Plant is strongly committed to employee safety and public and environmental protection. DGC recognizes that risks to the health and safety of employees, the public, and the environment may exist from potential release of airborne substances and fire or explosion. These risks are minimized through DGC's comprehensive Accidental Release Prevention and Emergency Response Program. This program integrates safety elements including design, installation, operating procedures, maintenance, and employee training associated with the processes at the Synfuels Plant. DGC implemented the following official policies concerning health, safety, and environment: DGC Board Policy 11 on General Safety and Health. It is the policy of Dakota Gasification Company to comply with all federal, state, and local safety and health standards. A strong safety and health program will be implemented to ensure that safe and healthful work places are provided to all employees, that safe work practices are employed, and necessary resources be committed to the program. DGC Board Policy 12 on Environmental Commitment and Compliance. It is the policy of Dakota Gasification Company to maintain compliance with all federal, state, and local environmental legislation and regulations. The Company recognizes the need to maintain a healthy environment for all employees and for citizens in the surrounding areas and commits its support to management in the pursuit of that need. The DGC Accidental Release Prevention and Emergency Response Program implements extensive controls to prevent accidental releases of toxic and flammable substances that could cause serious harm to workers, the public, or the environment. The DGC program incorporates measures to mitigate the severity of releases that do occur and minimizes the potential impact of releases through an emergency response plan that is coordinated with the Mercer County Disaster Emergency Services. 2. The Stationary Source and the Regulated Substances Handled The primary activities of the Synfuels Plant encompass the manufacture of synthetic natural gas (SNG) and other by-products from lignite coal using Lurgi gasification technology. The SNG production rate is approximately 170 million standard cubic feet per day (MMSCFD). The Synfuels Plant also generates, sells, and ships a number of other products, including anhydrous ammonia. The substances present at the Synfuels Plant in quantities above applicable thresholds and regulated by the Chemical Accident Prevention Provisions (CAPP), Section 112(r), of the Clean Air Act Amendments (CAAA) of 1990 are ammonia and flammable-gas mixtures containing various concentrations of carbon monoxide, carbon dioxide, methane, and hydrogen. The maximum inventories of Section 112(r) substances at the Synfuels Plant are approximately 65.6 million pounds of ammonia and approximately 150 thousand pounds of flammable-gas mixture. The ammonia is used for sales as a fertilizer, in the refrigeration systems, and in the production of ammonium sulfate. The flammable gas mixtures are used in the manufacturing of SNG as well as the gas feed for the ammonia production facility. 3. The Worst-Case Release Scenario and the Alternative Release Scenario The hazard assessment for the Synfuels Plant included computer analyses of potential releases from nine flammable-gas mixture process areas and three ammonia process areas to estimate the potential distance to explosion endpoints and toxic endpoints, respectively. Two of the Synfuels Plant process areas include both flammable-gas mixtures and ammonia, for a total of ten process areas analyzed. The impact analysis computer software refined modeling programs Degadis and SLAB, the Environmental Protection Agency (EPA) RMP*Comp software, which employs equations from EPA's Off-site Consequence Analysis Guidance, and the ARCHIE modeling program were used to evaluate the worst-case and alternative scenarios. Worst-case radiation and explosion scenarios were developed for all nine of the Synfuels Plant process areas where flammable-gas mixtures are handled. The worst-case endpoints resulted in a pressure wave capable of shattering windows and causing possible related injuries. The worst-case scenario considered for this process involves a flammable-gas mixture, namely methane. The quantity released in the worst of the nine simulated scenarios was assumed to be 20,500 pounds from Gas Compression (1900), which classifies as a Program 1 process. It was assumed that the entire quantity would be released as a vapor which finds an ignition source with a yield factor of ten percent of the available energy released in the vapor cloud explosion to determine the distance to the explosion endpoint. Under worst-case weather conditions, the maximum dist ance to the flammable endpoint of one pound per square inch (PSI) overpressure is 0.22 miles. The computer simulations predicted that explosions from flammable-gas mixtures would not occur off-site, resulting in no risk to the public from fire and explosion. The development of potential impacts from ammonia handling areas, Ammonia Storage and Loading (6000), Ammonia Production (4400), and Ammonia Refrigeration in Rectisol (1400), included the computer simulation of potential worst-case and alternative release scenarios for the three Synfuels Plant ammonia handling areas. The Section 112(r) toxic endpoint for ammonia is the ERPG-2 one-hour exposure limit of 200 parts per million. An ERPG-2 value is the maximum concentration below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair an individual's ability to take protective action. The worst-case release scenario involves a catastrophic release from the Ammonia Storage (6000) process area. Passive mitigation controls involving a dike around a 60 million pound refrigerated storage tank were taken into account to calculate the worst-case impact from that source. The mitigated release rate from the analysis of the refrigerated storage tank was estimated at 20,512 pounds per minute. The diked area around the refrigerated tank was estimated to release approximately 1.23 million pounds over one hour, the toxic endpoint threshold exposure time. As a result of accounting for the 200,708 square foot diked area around the large refrigerated storage tank, the simulated release from this 60 million pound tank was determined not to represent the worst-case impact. The worst-case toxic endpoint distance was determined to occur with an ammonia release from a smaller pressurized tank. The predicted worst-case impact was from the simulation of an unmitigated release of the entire contents of a one million gallon pressurized ammonia tank. The release from the pressurized tank was required to be simulated as a ten-minute release of the entire contents, which resulted in a release rate of 545,540 pounds per minute and the total release of approximately 5.46 million pounds of ammonia. The worst-case scenario was simulated at a required Class F atmospheric stability, or very stable, and a 1.5 meters per second wind speed. Simulated worst-case ammonia releases were predicted, using the Degadis refined computer modeling program to have toxic endpoint impacts out to 4.5 miles from the plant site release point. Such a catastrophic release is extremely unlikely if even possible. DGC was also required to perform a computer simulation of a more realistic alternative ammonia release since the worst-case ammonia impact extended off-site. It is important to simulate the types of accidents which are more realistic and could potentially occur with off-site impacts. A number of p otential alternative releases were examined and a scenario having maximum potential to occur in conjuction with maximum off-site impacts was selected for an alternative scenario. The alternative scenario resulting in the maximum toxic endpoint distance involved the simulation of overpressurizing the same 1,000,000 gallon tank used in the worst-case analysis and the subsequent release of ammonia through pressure release valves. The alternative scenario was simulated to occur at a continuous release rate of 2,045 pounds per minute with a total release of 122,700 pounds of ammonia over one hour. The alternative release was simulated with an average site wind speed of 5.3 meters per second and a corresponding typical atmospheric stability of Class D, or neutral. The predicted maximum distance using the SLAB computer program and the more realistic alternative release to the ammonia toxic endpoint was 1.5 miles. The other alternative release scenario assessments resulted in only on-site or industrial site impacts and no residential receptors off-site. 4. The General Accidental Release Prevention Program and the Chemical Specific Prevention Steps The Synfuels Plant has complied with the accidental release prevention requirements set out under Title 40 of the Code of Federal Regulations, Part 68 (40 CFR 68). This facility was designed and constructed in accordance with the National Fire Protection Association (NFPA) Standards and implemented the provisions of "Safety Requirements for the Storage and Handling of Anhydrous Ammonia, K-61.1," published by the American National Standards Institute, Inc. A number of processes at the facility are subject to the Occupational Health and Safety Administration (OSHA) Process Safety Management (PSM) Standard under 29 CFR 1910.119. The Synfuels Plant is also subject to the Emergency Preparedness Community Right-to-Know Act (EPCRA) Section 302 notification requirements. The facility is fully compliant with each of the applica ble health, safety, and environmental programs. The Chemical Release Prevention Program addresses areas such as process design (redundancy, safety interlocks, process controls such as flares, and spared equipment), procedures (operating, inspection, preventive maintenance, predictive monitoring), and training (operating procedures and testing of technicians). The following sections briefly describe the elements of the Accidental Release Prevention Program that is in place at the Synfuels Plant. Process Safety Information The Synfuels Plant maintains a detailed record of safety information that describes the chemical hazards, operating parameters, and equipment designs associated with all processes. Process Hazard Analysis The Synfuels Plant conducts process hazard analyses to ensure that hazards associated with our processes are identified and appropriate safeguards exist. The methodology used to carry out these analyses is compliant with applicable regulations and guidelines. The studies are conducted by a team of qualified personnel with expertise in engineering and process operations and are revalidated at a regular interval of five years. Any recommendations related to the hazard analysis are addressed in a timely manner. Operating Procedures The Synfuels Plant maintains written operating procedures for the purpose of safely conducting activities within our covered processes. These procedures address various modes of operation such as normal operations, temporary operations, emergency shutdown, emergency operations, and normal shutdown and startup after a turnaround. The information is regularly reviewed with and readily accessible to operators involved in the processes. Training The Synfuels Plant has a comprehensive training program in place to ensure that employees who are operating processes are competent in the operating procedures associated with these processes. Refresher training is provided at least every three years and more frequently as needed. Mechanical Integrity The Synfuels Plant carries out highly documented maintenance checks on process equipment to ensure proper operations. Process equipment examined by these checks includes among others: pressure vessels, storage tanks, piping systems, relief and vent systems, emergency shutdown systems, controls, and pumps. Maintenance operations are carried out by qualified personnel with appropriate training in performing these job tasks. Furthermore, these personnel are offered specialized training as needed. Any equipment deficiencies identified by inspection checks are corrected in a safe and timely manner or parameter limits are implemented to safely operate the equipment until the deficiency has been corrected. Management of Change Written procedures are in place at the Synfuels Plant to manage changes in process chemicals, technology, equipment, and procedures. Process operators, maintenance personnel, or any employee whose job tasks are affected by a mod ification in process conditions are informed and trained on any modification. Pre-startup Reviews Pre-startup safety reviews related to new facilities or significant modification in covered process areas are conducted at the Synfuels Plant. These reviews are conducted to confirm that construction and equipment are in accordance with design specifications. These reviews also address appropriate safety, operations, maintenance, and emergency response procedures, if applicable, are in place and adequate as well as employees trained in operating the process. Compliance Audits The Synfuels Plant conducts procedural compliance and regulatory compliance audits every three (3) years to determine whether the provisions set out under applicable health and safety requirements, which will include the Risk Management Plan (RMP) Rule, CAAA Section 112(r), are being implemented. The corrective actions required as a result of audit deficiencies are monitored to ensure implementation. Incident Investigation The Synfuels Plant promptly investigates any incident that has resulted in, or could reasonably result in, a catastrophic release of a regulated substance. These investigations are undertaken to identify the situation leading to the incident as well as any corrective actions to prevent the release from reoccurring. All reports are retained for a miminum of five years. Employee Participation The Synfuels Plant believes that process safety management and accident prevention is a team effort. Employees are strongly encouraged to express their views concerning accident prevention issues and to recommend improvements. In addition, plant employees have access to all information created as part of the facility's implementation of the RMP Rule, including information resulting from process hazard analyses in particular. Contractors On occasion, DGC hires contractors to conduct specialized maintenance and construction activities. Prior to selecting a contractor, a thoroug h evaluation of safety performance of the contractor is carried out. The Synfuels Plant has a strict policy of informing the contractors of known potential hazards related to the contractor's work and the processes. Contractors are also informed of all the procedures for emergency response should an accidental release of a regulated substance occur. 5. Five-year Accident History The Synfuels Plant has had an excellent record of preventing accidental releases over the last five years, reflecting the good safety at the facility. Due to our stringent release prevention policies, only four reportable accidental releases as defined in 40 CFR 68.42 have occurred in the last five years. The four accidents were relatively small, and none of them resulted in off-site impacts. Since there was not an off-site impact, the Emergency Response Program for off-site notification was not required or invoked. 6. Emergency Response Plan The Synfuels Plant carries a written emergency response pl an to deal with accidental releases of hazardous materials. The plan includes all aspects of emergency response including response to and mitigation for fires, explosion, hazardous and gas releases; adequate first aid and medical treatment; evacuations; notification of local emergency response agencies and the public; as well as post-incident decontamination of affected areas. Potential off-site impacts are addressed through an in-place emergency response plan developed in conjunction with the PSM and DGC health, safety, and environmental policies. In case of an off-site release, the emergency response plan directs DGC Protection Services to notify Basin Electric Headquarters Security, which in turn will notify according to the following priority list: 1. Residents and Businesses 2. Mercer County Sheriff's Office 3. North Dakota State Emergency Commission 4. National Response Center 5. On-call DGC Environmental Department Representatives The current emergency response plan ca lls for Basin Electric Headquarters Security to notify residents and businesses downwind of the Synfuels Plant to a distance of 2.5 miles. The Mercer County Disaster Emergency Services is also notified, and they are responsible for notifying residents and businesses beyond 2.5 miles downwind from the Synfuels Plant. In case of an accidental release with potential off-site releases, the public will be instructed to either shelter-in-place or evacuate. To ensure proper functioning, our on-site emergency response equipment is regularly inspected and serviced. In addition, the plan is promptly updated to reflect any pertinent changes taking place within our processes that would require a modified emergency response. DGC health and safety procedures ensure that emergency response facility personnel are well trained through the use of an extensive in-house and off-site training program. 7. Planned Changes to Improve Safety Before EPA adopted the new RMP Regulations, DGC took proactiv e steps upon initial ownership to ensure worker safety and protection of the public and environment by implementing policies concerning health, safety, and environment. The existing DGC emergency response plan was modified to conform with the requirements of Section 112(r) of the CAAA. Changes to the existing emergency response plan primarily involved performing a new Hazard Assessment and putting the existing Emergency Response Program and OSHA Process Safety Management Program into Seciton 112(r) format. Continuous efforts are on-going for improvements in the Chemical Release Prevention Program as illustrated by the example of the installation of new computer control systems in operating areas and the efforts in the preventive maintenance program of equipment. Several developments are being evaluated in the Safety and Health program at DGC. These activities may include some, or all, of the following activities over the next few years: Plant Safety and Health procedures and poli cies will be revised and updated to maintain consistency with government regulations or to meet the needs of the facility. Safety and Health training programs will be developed or revised to comply with government regulations or to meet the needs of the facility. A safety and health program testing process will be initiated with field personnel to determine their knowledge level and help identify training needs. The DGC Chemical Safety Information Manual will be updated to include additional process areas, chemicals, and first aid information for each identified chemical. This manual contains three sections: general information regarding chemical safety and hazard detection, specific information regarding major chemicals found at the facility, and information on the plant process areas and the chemicals found in each area. A project to perform an industrial hygiene risk assessment for each process unit is being considered. This risk assessment would include: 1. Identifying all chemicals in each process unit 2. Assessing the characteristics of the chemicals, including toxicity 3. Assessing the magnitude of a potential release 4. Determining potential exposure to the chemical by exposure groups 5. Characterizing the health risks The possibility of completing employee exposure assessments and including them in the Safety/Health/Medical/Environmental database is being explored. This project will attempt to build a Job Exposure Profile system to include the following: 1. Frequency of employee contact with a hazardous agent 2. Intensity of exposure 3. A summary of the actual measured exposure 4. The amount of time per shift that exposure occurs 8. Certification Statement 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. __________________________________________ ___________________________________ Al Lukes , Vice President and Chief Operating Officer Date |