Farmland Industries, Inc., Enid Nitrogen Plant - Executive Summary |
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Risk Management Plan Executive Summary Farmland Industries, Inc. Enid Nitrogen Plant Enid, Oklahoma Farmland Industries, Inc. operates a nitrogen fertilizer manufacturing facility at Enid, Oklahoma. As a nitrogen fertilizer manufacturing facility, producing anhydrous ammonia and other fertilizer products utilizing ammonia as a feed stock; this facility is subject to the Environmental Protection Agencies Risk Management Program rules under the Clean Air Act Amendments of 1990. The Risk Management Program rules require for facilities handling threshold amounts of certain chemical substances to submit Risk Management Plans for the prevention of accidental releases of these substances. The plan requirements include submission of the risk management plan to include hazard assessments defining possible offsite impacts of certain regulated substance release scenarios, a five-year accident history, description of the facilities accidental release prevention program, and an emergency r esponse program. The following is the Executive Summary of the Risk Management Plan for Farmland Industries, Inc., Enid Nitrogen Plant at Enid, Oklahoma. Enid Facility Description The Enid Nitrogen Plant is a nitrogen fertilizer manufacturing facility consisting of two large scale, natural gas feed ammonia production units, a urea production unit, and an integrated urea-ammonium nitrate (UAN) production unit. These products are primarily used as agricultural fertilizers. Ancillary facilities include a carbon dioxide pipeline compressor station and an Argon separation plant. Initial operation began in 1974 with the first ammonia unit with major additions of the second ammonia unit in 1976, the urea unit in 1982, and the UAN unit in 1992. The facility produces, handles, and stores large quantities of anhydrous ammonia in its operations. The ammonia units use natural gas, air, and water for the production of ammonia. Ammonia is used along with by product carbon dioxide to produc e solid urea fertilizer. Urea-ammonium nitrate solution is produced by combining urea in liquid form with ammonium nitrate made by using ammonia to neutralize nitric acid made from ammonia and air. Each of these production units and ammonia storage and handling constitute the processes covered by the EPA Risk Management Program rule. Regulated substances include the primary product of the plant, anhydrous ammonia. In addition, flammable substances including methane (natural gas) and hydrogen (produced as an intermediate in ammonia production), are regulated under Risk Management. Finally, chlorine is also present in regulated threshold quantities on the site. It is used as an agent to control algae and bacteria in the cooling water systems associated with the production units. Accidental Release Prevention and Emergency Response Policy The management and employees of this facility are committed to the prevention of any accidental releases from this facility. It is this faci lity's policy to eliminate significant accidental releases of any substance and eliminate minor releases to the extent possible. Prevention of accidental releases is critical to the safe operation of this plant, to the safety of its employees, and to the safety of the general public. To achieve its goals of accident and accidental release prevention, the facility is committed to the following: * A knowledgeable and highly trained and motivated employee group * A well designed facility that is maintained and operated in a superior manner * Improvements that enhance safety and accident prevention where appropriate * Excellence in safety programs and practices and a superior safety and accident record * Preparation and training for emergency response and mitigation Prevention Program The Enid Nitrogen Plant adheres to the requirements of OSHA Process Safety Management and has written policies and procedures addressing all aspects of Process Safety Management and EPA Prevention Program s. In all of its years of operation, the facility has addressed the elements of accident prevention included in these programs. The Prevention Program consists of several elements and policies which are briefly outlined below: * Employee Participation-Employees are involved in all aspects of the program and are provided any information developed in the program. Employees participate in process reviews, assist with development of procedures, and all other aspects of the program. * Process Safety Information-The plant maintains all necessary process information and records including: information on the hazards of the chemicals; process technology with safe operating limits; and equipment records and design requirements * Process Hazard Analysis--Process hazard analysis and review has been conducted by employee teams to identify and correct any perceived hazards. These reviews are updated on a schedule or more often if changes indicate the necessity of additional review. * Oper ating Procedures--Operating procedures are in place for all aspects of operation including emergency operation and shutdown, operating limits and methods to correct or avoid deviations from limits, safety and health considerations of operations and the chemicals involved, and safety system operation and function. * Operator Training-All operators are trained initially in the process and its operating procedures and receive refresher training not less than every three years. In reality, operator training is a continual and ongoing process. * Contractors-Contractor selection includes review of safety performance and programs. Contractors are oriented to known hazards in the facility, the emergency plan, and are required to adhere to facility safe work practice procedures. Contractor performance is periodically evaluated as necessary to ensure work is completed in a safe and correct manner. * Pre-startup Safety Review-A safety review is conducted on any new facility and for any significant modification of the facility to ensure that construction and equipment is installed in accordance with design; all necessary procedures are in place; training is completed; and that hazard analysis or requirements of management of change are completed. * Mechanical Integrity-Procedures for periodic inspection and testing of equipment and correction of equipment deficiencies are in place. A quality assurance procedure ensures equipment, parts, materials, and installations are suitable for the applications intended. Maintenance employees are trained in the process hazards and in safety procedures for their work. * Safe Work Practices-Procedures and policies for work permits and maintenance and operating actions are in place for accident prevention. * Management of Change-No changes are allowed in the process or procedures without review and authorization. The procedure is to ensure the safety of the change. * Incident Investigation-Any incident which results in a s ignificant release or could have reasonably resulted in such a release is promptly investigated by a facility team. Findings of the investigation, recommendations for corrective action and resolution of the recommendations and corrective actions are documented. * Emergency Planning and Response-The Process Safety Management/Prevention Program includes the facility Emergency Response Plan. * Compliance Audit-The program is audited at least every three years to verify compliance with these procedures. Findings of the audit are documented and any deficiencies are corrected and documented. The audit is conducted by persons knowledgeable of the facility processes, but not directly connected with the facility. The facility is diligent in adhering to and maintaining its Process Safety/Prevention Program. Emergency Response Plan The Enid Nitrogen Plant has a written Emergency Response Program as required by the Risk Management Plan rule and other Environmental Protection Agency and O SHA rules. This Plan is coordinated with the local community response plan and is available to those responding agencies. Emergency planning and Community Right-To-Know information as required under SARA Title III has been provided to the State Emergency Response Commission, Local Emergency Planning Committee, and other appropriate agencies such as the local fire department. The facility is an active participant in the Local Emergency Planning Committee. It includes various local emergency response agencies in its emergency planning. Employees receive annual training in the response plan and also receive various safety training, both in general, and in the competencies relative to their required roles in the plan. Periodically the plan is practiced in a table top, classroom type setting, and it also is drilled in mock emergencies including participation by outside responding agencies. 5-Year Accident History The Risk Management rule requires inclusion of the five-year accident history of the facility for all accidental releases that resulted in deaths, injuries, or significant property damage on site, or known offsite deaths, injuries, evacuations, sheltering in place, property damage, or environmental damage. The Enid Nitrogen Plant has had four minor injuries which qualify as accidents. All involved releases of very small quantities of ammonia which caused minor chemical burns to the skin of employees working on the system or in the area. In all four cases, the employees received medical attention and were immediately released to return to work. The plant has never had a release which has had an off-site impact. Synopsis of Worst and Alternate Case Release Scenarios The Risk Management Plan rule requires a hazard analysis for worst case and alternate case accidental release scenarios for regulated substances present in threshold quantities at the site. For this facility, the regulated substances include anhydrous ammonia and chlorine as regulated to xics, and flammables as a class which include methane and hydrogen. The rule requires an analysis of the worst case toxic as that scenario affecting the greatest distance and a worst case flammable accident as a vapor cloud explosion. Alternate scenarios, which are more reasonably likely events, for each regulated toxic and flammables in general must also be presented. Worst Case Toxic Release Because of the seasonal nature of fertilizer use and application in agriculture, large quantities of the ammonia produced at this facility must be stored until needed by farmers for application. The RMP rule requires that the largest amount in a single vessel be considered the release quantity for the worst case event unless smaller quantities handled at different conditions result in a greater distance to the regulated endpoint. For this facility, the largest single quantity of anhydrous ammonia is held in the cryogenic storage tanks. This quantity can total 30,000 tons in each tank. Farmland also modeled the 200 ton pressure storage tanks in which warm ammonia is held for shipment and for use in facility plants. The worst case release assumes, as required by the rule, that the entire amount of one full tank is released as a result of a catastrophic failure. The weather conditions must be those which create the longest affected distance. These unlikely events were modeled by a publicly available model (DEGADIS) which is known to provide reasonable estimates of concentrations and distances associated with release events. In the case of the Enid facility, the release of 200 tons of warm ammonia created the worst offsite consequence. This is because the 30,000 ton storage tanks hold the ammonia at -28 degrees F inside a diked area which limits the size of the pool of ammonia. The 200 ton pressure tanks hold the liquid ammonia at 40 to 60 degrees F which causes more rapid vaporization. In addition, a worst case failure of a chlorine container was similarly mo deled, with a smaller plume distance than the 200 ton ammonia tank. It should be emphasized that the possibility of such an event as described by the worst case is so low as to be non-existent. Analysis of this unlikely scenario was completed as required by the rule. Facility maintenance and inspection programs address the integrity of process and storage vessels, and preclude such massive and improbable failures. Worst Case Flammable As the rule requires, the largest quantity flammable release and a subsequent vapor cloud explosion must be analyzed as the worst case for these substances. In this facility, a failure releasing the entire contents of the ammonia synthesis loop constitutes the largest flammable release. This quantity is assumed to result in a vapor cloud explosion with impact distance determined by the EPA Offsite Consequence Analysis formulas. Although large volumes of flammable gases are handled daily by the plant, actual in-process inventory is relatively small , especially considering the inert gases and steam in the mixtures. Offsite impact distance is relatively limited as a result. Alternate Case Toxics Ammonia "More likely" release events tend to concentrate in areas where the ammonia product is handled such as loading and other transport activities. Significantly lower quantities are involved, various shutdown safeguards are present as they are throughout the plant, and operator intervention all tend to mitigate and limit the consequences of failures. Such events can include failure of smaller valves, lines, and hoses. The alternate release scenario, modeled with the DEGADIS model for this facility, is breaking off a 3/4" vent and drain valve from the ammonia truck and rail loading system. The modeled offsite impact distance is substantially lower for more reasonable, but still not necessarily likely release events. Chlorine Chlorine is used at several locations in this plant to control algae and bacteria in the cooling water systems, much as it is also used in swimming pools. It is used as a gas from one ton chlorine cylinders through an injection system to the circulating cooling water. The alternate release scenario assumed is failure of the connecting tubing from the cylinder and release of gaseous chlorine. This release and offsite consequence was modeled using the DEGADIS dispersion program. Flammables Large volumes of flammable gases are handled throughout the plant, even though actual physical inventory is relatively low, given the quantity of inert gases and steam in the mixtures. More likely flammable release events include failures of smaller pipes and lines or blowing relief valves in comparison to the large release contemplated in the worst case analysis. The alternate scenario used was an extended blowing of the synthesis gas compressor relief valve due to a loss of reaction in the synthesis converter. The relief valve lifts to maintain loop pressure while the synthesis compre ssor continues to send gas to the synthesis loop. The time was extended to three minutes in order to vent enough gas to provide an off-site consequence. The scenario also assumes no wind and that the gas cloud which consists of mostly hydrogen and inert gases stays intact. The impact distance calculation for this event utilized the EPA Offsite Consequence Analysis formulas. More reasonable events result in minimal impact distances. Planned Changes for Safety Improvements Safety improvements are a continual and ongoing process at the facility which is facilitated by the Prevention Program/Process Safety Management Program. Formal process hazard analysis is conducted at least every five years, but review is constant through management of change procedures, operator training, incident investigation, and mechanical integrity programs. As a result, changes relevant to safety occur continuously as needs are identified through these procedures and policies. 6 |