McKamie Gas Plant - Executive Summary |
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The McKamie Gas Plant is an on-shore natural gas processing facility located on County Road 36, Lafayette County, near Stamps, Arkansas. The facility was constructed in the early 1940s by the predecessors of Arco and Exxon, and was designed to process sweet and sour natural gas. Phillips Petroleum acquired the Plant in 1969. In December 1998, MKP Production Company, L.L.C. (MKP), who owned and operated the facility at that time, and affiliated entities filed voluntary Chapter 11 petitions under the U.S. Bankruptcy Code. Energy Income Fund, L.P. (EIF), the primary secured creditor of the McKamie Gas Plant assets, filed a Plan of Liquidation with the U.S. Bankruptcy Court to protect EIF's security interest in those assets. Under the plan of liquidation approved by the U.S. Bankruptcy Court, Longview Gas Company, an EIF affiliate will become the owner of the facility. The Plant has been temporarily shut down since April 1999. It is anticipated that the Plant will be re-activated in February 2000. When in operation, the Plant produces butane liquids, propane liquids, and natural gasoline from gas feed. The Plant will consist of two residual compressor engines, a steam boiler, a sulfur recovery unit, an emergency flare, two refrigerant compressor engines, two overhead compressor engines, a glycol reconcentrator, a regeneration gas heater, a heat medium heater, and a nitrogen rejection unit. The Plant is capable of processing up to 15 million standard cubic feet per day (mmscf/d) of natural gas when operational; however, it had only been processing 9 to 10 mmscf/d of natural gas before it was shut down. The following is a summary of the facility's risk management program, which has been developed in preparation for the re-activation of the facility. 1. ACCIDENTAL RELEASE PREVENTION AND EMERGENCY RESPONSE POLICIES The McKamie Gas Plant has had a long-standing commitment to worker protection and public safety, as demonstrated through the accidental release an d emergency response programs previously implemented at the Plant. These programs provide information regarding personnel training in accidental release and response procedures, process operations, and health and safety practices; written operation and maintenance procedures for each process; hazard analysis and response; and hazard communication. It is Longview Gas Company's policy to implement reasonable controls to prevent accidental releases of regulated substances, as well as train personnel to respond, control, and mitigate releases, if necessary. 2. FACILITY AND REGULATED SUBSTANCES When operational, the McKamie Gas Plant processes gas from the following production fields: 7 Low-pressure sour gas and liquids from the McKamie-Patton Unit; and, 7 High-pressure sweet gas and liquids from the Dorcheat-Macedonia Field. Low-pressure sour gas from the McKamie-Patton Unit enters an inlet separator where gas and condensate are separated. High-pressure sweet gas from the Dorchea t-Macedonia Field enters the high-pressure inlet separator where the gas and condensate are separated. Condensate from both separators is directed to the condensate stabilization unit where light ends are volatilized. Condensate from the stabilization unit is blended with liquids from the de-propanizer. This blend is sent to the de-butanizer where butane is removed and sent to pressurized storage. The remaining liquids (natural gasoline, pentanes and heavier) are also sent to pressurized storage. Low-pressure sour gas from the low-pressure inlet separator and the volatilized light ends from the condensate stabilization unit are compressed and combined with the high-pressure sweet gas stream. This combined stream is sent to the amine contactor where Hydrogen Sulfide (H2S) and Carbon Dioxide (CO2) are removed by the lean amine solution in the contactor. Heat from the sulfur recovery unit (SRU) waste stream is used to regenerate the rich amine solution. Acid gas produced during th e amine regeneration, consisting mostly of H2S and CO2, is sent to the SRU where H2S is reduced to elemental sulfur. Liquid molten sulfur is loaded into trucks and transported from the Plant. H2S not converted into elemental sulfur is converted to SO2 in the SRU incinerator. The sweetened natural gas flows from the amine contactor to the Triethylene Glycol (TEG) contactor for dehydration. Natural gas encounters a counter-flowing stream of lean TEG in the contactor where water vapor is absorbed from the gas stream. The dehydrated natural gas exits the contactor and the rich TEG (water laden) is sent to the TEG reboiler for regeneration. A natural gas fired reboiler heats the rich TEG to approximately 375: F. This heating produces a gas stream consisting mostly of water and TEG vapor, with entrained Volatile Organic Compounds (VOCs). This gas stream is sent to a reflux condenser where the gas is cooled, allowing the TEG to condense. The lean TEG is then routed back to the contac tor. The cooled gas stream, now consisting mostly of water vapor and entrained VOCs, exits the reflux condenser vent and is further cooled in a secondary condenser where water and condensable VOCs (mostly benzene, toluene, ethylbenzene and xylene - (BTEX)) are removed and sent to storage. Vapors from the secondary condenser vent do not vent to the atmosphere, but are recycled back into the process. The sweetened, dry natural gas is sent to a mole sieve dehydration unit for additional water vapor removal in preparation for the cryogenic unit. The only air emissions associated with the mole sieve unit are from the regeneration gas heater used to regenerate the mole sieve beds. The natural gas stream is next sent to the Joule-Thompson cryogenic unit where ethane and heavier components are extracted from the gas in liquid form, and sent to pressurized storage. The ethane and heavier liquids stream is sent to the de-ethanizer where ethane and lighter components are separated and mix ed with the residue gas for compression into the sales pipeline. The liquid stream, now consisting of propane and heavier components, is sent to the de-propanizer where propane is removed and sent to pressurized storage. The liquid stream, consisting of butane and heavier components, is sent to the de-butanizer where butane is removed and sent to pressurized storage. The remaining liquid, consisting of pentanes and heavier components, is also sent to pressurized storage. Propane, butane and natural gasoline are periodically loaded into trucks and sold. A direct-fired heater provides the process heat for the de-ethanizer, de-propanizer and de-butanizer. Longview plans to reactivate an existing nitrogen rejection unit (NRU) for the removal of nitrogen in the sales gas stream. The NRU will add one additional process vent. The current air permit calls for the emergency flare to be disconnected, but not dismantled. However, the facility can not be operated safely without the availa bility of a flare. Consequently, Longview has submitted a permit modification application to allow for the emergency use of the flare. The flare will only be used to safely vent the gas that would be blown down in an emergency, unless otherwise authorized by the appropriate regulatory agencies. The flare will not be used to burn acid gas in the event that the SRU is not operating, unless otherwise authorized. Natural gas liquids (NGL) (propane, butane, pentane, ethane, natural gasoline, and condensate) and Hydrogen Sulfide (H2S) are the regulated substances that are processed and stored at the facility in amounts above the threshold limit. 3. OFF-SITE CONSEQUENCE ANALYSIS RESULTS The EPA-RMP*Comp Model was used to predict the worst-case and alternative release scenarios for flammable and toxic substances present at the McKamie Gas Plant. The off-site consequence analysis for the McKamie Gas Plant was performed for two processes: sulfur recovery and natural gas processing. T he sulfur recovery process involves the regulated toxic substance H2S in amounts that exceed the threshold quantity. This means that the worst-case and alternative-case analyses for the toxic substance need to be addressed for H2S. The natural gas process involves regulated flammable substance such as propane, butane, pentane, ethane, natural gasoline, and condensate in amounts that exceed the threshold quantity. This means that the worst-case and alternative-case analyses also need to be addressed for these substances. The worst-case scenario for flammable substances is focused on a release consisting of the entire contents of all five pressurized storage tanks located in the same area, and the contents from the large storage tank located on the other side of the facility (a total of six tanks). The alternative-case scenario, however, focuses on a release that would consist of the contents from one of the five storage tanks and the large storage tank located on the other side of th e facility. Flammable Substance Worst Case: The worst-case release scenario for a flammable substance consists of an instantaneous release of NGL from six storage tanks and a vapor cloud explosion. This scenario is based on the assumption that the entire quantity of the flammable substance will form a vapor cloud and no liquids will be released due to inadequate pressure. Therefore, the use of passive mitigation systems, such as storage tank containment dikes, will not be applicable due to the nature of the substance released. It is predicted that a worst-case release will have an off-site impact. The end point or point at which the vapor cloud is reduced to 1 psi overpressure is estimated to be at a distance of 0.6 miles from the Plant. A series of safety devices on the system (e.g. high pressure alarms) makes it extremely unlikely that the worst case scenario would occur. Alternative Case: The alternative-case release scenario for flammable substances at the McKamie Gas Plan t consists of the rupture of one of the NGL pressurized storage tanks. This scenario differs from the worst-case scenario in that it is assumed that a smaller volume of NGL is being stored in the tanks (75% of the tank maximum capacity) and that this volume is released to the ground. Passive mitigation measures, such as the use of storage tank containment dikes, will contain the liquids, if present. However, in this case, it is assumed that the NGL will vaporize due to the absence of adequate pressure and the vapors will ignite in a vapor cloud fire. The end point or point at which the vapor cloud is reduced to the Lower Flammable Limit is estimated to be at a distance of 0.1 miles from the Plant. The use of safety devices reduces the probability of the alternative-case scenario occurring. Toxic Substance Worst Case: The worst-case release scenario for a toxic substance consists of an instantaneous release of Hydrogen Sulfide (H2S) from the processing pipeline. This scenario is based on the assumption that the entire contents of the pipeline are released. The use of passive mitigation systems will not be applicable due to the nature of the substance released. It is predicted that a worst-case release will have an off-site impact. The end point or point at which the released gas concentration is reduced to 0.042 mg/l is estimated to be at a distance of 13 miles from the Plant. A series of safety devices on the system (e.g. process detectors) makes it extremely unlikely that the worst case scenario would occur. Alternative Case: The alternative-case release scenario for toxic substances at the McKamie Gas Plant consists of an instantaneous release of Hydrogen Sulfide (H2S) from the processing pipeline. This scenario is based on the assumption that only a portion of the pipeline contents is released. It is assumed that the H2S will be released due to the pipeline leak. The end point or point at which the released gas concentration is reduced to 0.042 mg /l is estimated to be at a distance of 2.0 miles from the Plant. The use of safety devices reduces the probability of the alternative-case scenario occurring. 4. GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM AND CHEMICAL SPECIFIC PREVENTION STEPS The McKamie Gas Plant is subject to the requirements of the Occupational Safety and Health Administration's (OSHA) Process Safety Management (PSM) Standard. The practices employed at this facility which are most important to the PSM accident prevention program are described in more detail below. This accident prevention program is also applied to all RMP covered processes at the McKamie Gas Plant. Employee Participation Active employee participation and involvement in the development and implementation of the McKamie Gas Plant's PSM program will be an important step toward achieving the objective of preventing or minimizing the effects of catastrophic releases of toxic, reactive, flammable, or explosive chemicals. Employee involvement will ensure that all perspectives regarding PSM are considered, and that the best ideas will be implemented. Open communication will be encouraged between supervisors and employees regarding all safety and health issues. The McKamie Gas Plant will strive to promote employee involvement in developing and implementing safety and accident prevention standards. Safety meetings, special training programs for emergency response and first aid, and hazard communication training will be scheduled on a regular basis to ensure that employees are properly trained in health and safety issues and have the opportunity to voice their concerns regarding such issues. Employees will also be encouraged to discuss safety and accident prevention practices with their supervisors if they have questions, comments, concerns, or suggestions. Process Safety Information The McKamie Gas Plant will maintain complete and accurate process safety information records concerning process chemicals, technology, and equipment. Technical documents describing process operations and process design and construction will be available to all employees, including operators, Process Hazard Analysis (PHA) team members, training coordinators, contractors, pre-startup safety review team members, and emergency preparedness team members. These documents will describe the properties and hazards of all process chemicals and include specific chemical inventories; the limits of key process parameters; and the equipment design basis/configuration including the materials of construction, design pressure and temperature ratings, and electrical ratings of equipment. This information, in combination with written safety procedures and trained personnel, will provide the basis for developing and implementing all inspection and maintenance procedures, as well as evaluating proposed process and facility changes to ensure that safety features in the process will not be compromised. Process Hazard Analysis (PHA) The McKa mie Gas Plant will develop a comprehensive program to help ensure that hazards associated with process operations are identified and controlled. In this program, each process will be systematically examined to identify potential hazards and ensure that adequate controls are in place to manage these hazards should it become necessary. A team of employees who are familiar with the operation and maintenance and the engineering specifications of each process will evaluate process operations using the what-if checklist method. The team will identify the potential hazards associated with each process, evaluate the existing accident prevention and mitigation measures for each process, and make recommendations for additional prevention and/or mitigation measures as necessary. The PHA team findings will then be forwarded to management for resolution. Implementation of the mitigation measures identified by the PHA team will be based on the relative risk ranking assigned by the team. This r isk ranking method ensures that potential accident scenarios with the highest risk receive immediate attention. All management-approved mitigation measures identified by the PHA team will be tracked from start to finish. The final resolution of each PHA team finding will be documented and retained in the PHA files. The PHA team will conduct a hazard analysis review every five years for the life of the process to ensure that the process controls and/or process hazards will not significantly deviate from the original design safety features. The results and findings of these PHA reviews will be documented and retained in the PHA files and then be forwarded to management for consideration. The final resolution of each PHA team finding will be documented and retained in the PHA files. Operating Procedures The McKamie Gas Plant will maintain written operating procedures for all process operations. These procedures will include specific instructions and details pertaining to safety precautions, process hazards, and process operations. The operating procedures manual will be written in a clear, concise tone so that it will be applicable to both new and experienced operators. Training The McKamie Gas Plant will develop a comprehensive process operation and safety training program for its employees. New employees will receive basic training in gas plant operations and safety at the time of hire. All other employees will receive refresher training on process operations and safety on an annual basis to ensure that their skills and knowledge will be maintained at an acceptable level. Contractors The McKamie Gas Plant will develop operation and safety procedures for contractors that work at the facility during periods of increased maintenance or construction. This program will ensure that contractors perform their work in a safe manner and have the appropriate knowledge and skills to work on or near process equipment. Because of this program, contractors will be aware of the hazards of their workplace and understand the appropriate measures to take when hazards are encountered and understand and follow site-specific safety rules. These procedures will ensure that contractors are aware that they must inform gas plant personnel of any hazards encountered during their work. This information will be presented to the contractors during an orientation session that will be conducted prior to the start of work. The orientation session will also include a review of process operations, safety and health hazards, emergency response plan requirements, and safe work practices. Pre-startup Safety Review The McKamie Gas Plant will conduct a pre-startup safety review (PSSR) of any new facility or facility modification that requires a change in process safety information. The purpose of the PSSR is to ensure that safety features, procedures, personnel, and equipment will be appropriately prepared for startup prior to placing the equipment into service, t hat all construction will be completed in accordance with design specifications, and that all supporting systems will be operationally ready. The PSSR involves field verification of the construction and serves as a quality assurance function by requiring verification that accident prevention program requirements will be properly implemented. Mechanical Integrity The McKamie Gas Plant will establish practices and procedures for maintaining process equipment. The basic aspects of this program will include employee training, a written process equipment maintenance manual, regularly scheduled inspections and tests of process equipment, the correction of any process equipment deficiencies as needed and within a timely manner, and the application of quality assurance measures in equipment purchases and repairs. In combination, these practices will form a system that maintains the mechanical integrity of the process. Safe Work Practices The McKamie Gas Plant will establish safe work pra ctices to ensure employee safety during process operation and maintenance activities. These safe work practices will include hot work permits and lock-out tag-out procedures. Training of affected personnel in these areas will ensure that operation and maintenance activities are performed in a safe manner. Management of Change The McKamie Gas Plant will establish a comprehensive system to manage changes to all covered processes. This system will require that changes to items such as process equipment, technology (including process operating conditions) and procedures be properly reviewed and authorized by management prior to implementation. Changes will be reviewed to ensure that adequate controls are in place to manage any new hazards and verify that existing controls will not have been compromised by the change. Affected chemical hazard information, process operating limits, and equipment information and procedures will be updated to incorporate these changes. Operation and ma intenance personnel will then be provided the necessary training on the change. In addition to the accident prevention program requirements of the PSM program, the McKamie Gas Plant has installed safety devices on process equipment in order to ensure the safe operation of all processes. These devices aid in the detection, containment and/or control, and mitigation of accidental releases of regulated substances within the facility. (Detection devices include process detectors and alarms; containment and/or control devices including process relief valves, isolation valves, automated shutdown systems for specific process parameters, atmospheric relief devices, and redundant equipment and instrumentation, such as an uninterruptible power supply for process control systems; and mitigation devices include fire suppression and extinguishing systems and personal protective equipment, such as chemical protective clothing and self-contained breathing apparatus). Collectively, these preventio n program elements will help prevent potential accident scenarios that could be caused by equipment failure and human error. Longview Gas Company will continue to monitor developments in safety devices and equipment to ensure that the McKamie Gas Plant will operate in the safest manner possible. 5. FIVE-YEAR ACCIDENT HISTORY The McKamie Gas Plant has had an excellent record of accident prevention. Over the past five years, there has only been one minor incident at this facility. This incident occurred in December 1997 and was caused by the failure of a seal in the poly pipeline, which caused a gas leak. The responder was immediately notified when the incident happened. There were no on-site or off-site deaths or injuries caused by the incident. The faulty seal was replaced immediately after the incident was discovered. 6. EMERGENCY RESPONSE PROGRAM The McKamie Gas Plant will maintain a written emergency response manual to provide employees with information regarding worker prote ction and public safety in the event of a fire or explosion caused by the accidental release of a flammable or toxic substance. The procedures will address the notification of local emergency response agencies, post-incident cleanup and decontamination requirements, and employee training requirements. The emergency response manual will be updated when modifications are made to the McKamie Gas Plant facilities and changes are administered through the management of change process. The emergency response program for the McKamie Gas Plant will be developed to work in coordination with the Lafayette County Sheriff Department, the Stamps Fire Department, and the Arkansas State Police Department. Around-the-clock communications will be established between these departments and the McKamie Gas Plant, as well as the appropriate local emergency planning commission (LEPC) officials and other emergency response organizations. Periodic meetings of the emergency response committee will facilit ate incident response and public notification procedures. Emergency drills will be carried out periodically as part of the ongoing training process. A post drill review will be conducted to identify the strengths and weaknesses of the plan. Any areas that have been identified as needing improvement will then be addressed, and the plan will be modified. The modifications will then be communicated to employees and outside agencies. |