Evangeline Power Station - Executive Summary
ACCIDENTAL RELEASE PREVENTION AND RESPONSE POLICIES |
The Evangeline Power Station (EPS) has a long-standing commitment to workers and public safety. This commitment is demonstrated by the resources invested in accident prevention such as training personnel and considering safety in design, installation, operation, and maintenance of the facility's processes. The CLECO Evangeline L.L.C. policy is to implement reasonable controls to prevent foreseeable releases of substances.
CLECO Evangeline, L.L.C. operates the EPS located in Evangeline Parish, Louisiana. The EPS is a gas fired stream electric plant that produces approximately 330 megawatts of electricity during peak demand periods. EPS proposed to construct three combustion turbines fired by natural gas. The heat recovered by heat exchangers is used to turn electric generating units producing electricity for sale to homes and businesses. As evidenced in the ensuing text and based on criteria outlined in the Accident Release Pro
gram (ARP), the EPS is a Program 3 process.
The EPS was evaluated to determine if any regulated flammable or toxic substances were or would be present in the planned process and if they exceeded the threshold quantity. The three separate generating units and associated ammonia tanks are separate of each other. Therefore, for ARP Program purposes, these processes were considered separately. The identification of even a single vessel exceeding threshold quantities of a regulated flammable or toxic substance would subject a process to threshold determination for offsite consequence analysis.
CLECO Evangeline, L.L.C. identified one regulated toxic substance and no flammable substances above the threshold values at EPS. Three bullet tanks with a capacity of 10,000 gallons each, containing anhydrous ammonia were determined to exceed the threshold quantity. The identification of this exceedance indicates that the EPS is a covered process with a regulated substance subject to threshold
determination for offsite consequence analysis.
OFF-SITE CONSEQUENCE ANALYSIS RESULTS
Worst-Case Scenarios (WCS)
The Environmental Protection Agency (EPA) has defined a worst-case release as "The release of the largest quantity of a regulated substance from a vessel or process line failure that results in the greatest distance to a specific endpoint". A WCS analysis is required for each toxic substance in a covered process while only one WCS analysis is required for regulated flammable substances as a class. WCSs are assumed to occur at ground level with meteorological conditions defined as atmospheric stability class F (stable atmosphere), wind speed of 1.5 meters per second and an ambient air temperature of 25 degrees C, 77 degrees F. Topography for WCSs is distinguished between rural and urban.
CLECO Evangeline, L.L.C. did not find any flammable substances above threshold quantities at EPS.
CLECO Evangeline, L.L.C. identified anhydrou
s ammonia, a toxic gas, as being present in quantities in excess of threshold quantities. Toxic gasses include all regulated toxic substances that are gases at ambient temperature (temperature 25 degrees C, 77 degrees F), even if they are stored as liquids under pressure or refrigeration. For the consequence analysis, a gaseous release of the total quantity is assumed to occur in 10 minutes, regardless of storage conditions. For toxic liquids, the total quantity in a vessel is assumed to be spilled onto a flat, non-absorbing surface. For toxic liquids carried in pipelines, the quantity that might be released for the pipeline is assumed to form a pool. Passive mitigation systems may be taken into account in consequence analysis for both toxic gases and liquids. The endpoint for air dispersion modeling to estimate the consequence distance for a release of a toxic gas and liquid is presented for each regulated toxic gas and liquid is presented for each regulated toxic gas and liquid
in Appendix B of the OCAGD in Exhibits B-1 and B-2, respectively.
Anhydrous ammonia, used as an integral component of the nitrogen oxides emissions control system, is stored in three 10,000-gallon pressurized storage tanks at EPS. Although the three anhydrous ammonia tanks are not located such that a release from one tank would cause the release of anhydrous ammonia from one of the other tanks, the three tanks are considered to be part of one process. Consequently only one worst case toxic release has been included in this RMP. For the purpose of identifying the maximum release quantity for use in determining potential off-site impacts, it is assumed that the entire contents of one of the three anhydrous ammonia vessels is released to the atmosphere forming a vapor cloud. Using the criteria outlined in the ARP rule, this release represents the facility's worst-case scenario for toxic gas and liquids. Using administrative controls, only 46,327 pounds of anhydrous ammonia will be
stored in each tank. The distance to the toxic endpoint of a 10-minute release of 46,327 pounds of anhydrous ammonia was determined to be 4.0 miles.
Alternative Release Scenario (ARS)
An ARS describes an incident that is more likely to occur than those cited for a WCS. One ARS analysis is required for each listed toxic substance in a Program 2 or 3 process that exceeds threshold quantity while only one ARS analysis is required for all flammable substances as a class. For ARSs, both active and passive mitigation systems can be considered.
Alternative release scenarios for flammable substances should have the potential to cause substantial damage, including on-site damage. Alternative release scenarios for toxic substances should be those that lead to concentrations above the toxic endpoint beyond the process fenceline. Those releases that have the potential to reach the public are of the greatest concern.
EPS Alternative Release Scenario for Regulated Flammables
No flammable s
ubstances were found at EPS in quantities above threshold values.
EPS Alternative Release Scenario for Regulated Toxics
A single ARS for the anhydrous ammonia is required under the ARP Program. A hypothetical, but likely to occur, release scenario has identified for the anhydrous ammonia tanks. Seal failure on the anhydrous ammonia tanks causes a release from a one-inch opening at a pressure of 145 psia and a temperature of 77 degrees F, (298 degrees K). The release is assumed to continue for ten minutes. It was determined that a release lasting ten minutes would involve 1,176 pounds of anhydrous ammonia and would reach its toxic end point at 0.20 miles from the vessel.
FIVE YEAR ACCIDENT HISTORY
The EPS has not had any accidental releases during the past five years that meet the criteria for an accidental release as discussed in 40 CFR 68.42.
LOCAL EMERGENCY RESPONSE COORDINATION
The EPS as coordinated its emergency response activities with the local emergency planning and
response agencies as required n 40 CFR 68.12(b)(3).
GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM
CLECO Evangeline, L.L.C. and the EPS actively encourage all levels of employees and contract employees to participate in creating a safe work environment. This participation begins with well-established mechanisms of communication with all employees regarding covered process information. Employees are involved in maintaining PSM rule compliance based on their knowledge, skill, job responsibilities, and experience. Specific ways that employees can be involved in the accident prevention program are documented in an employee participation plan that is maintained by the company.
Process Safety Information
The EPS maintains written information intended to provide a foundation for identifying and understanding the process hazards. This information addresses chemical properties, inventories, and associated hazards, as well as for key process parameter limits and equipment design basis/con
figuration information. Specific departments within the plant are assigned responsibility for maintaining up-to-date process safety information.
Chemical-specific information, including exposure hazards and emergency response/exposure treatment considerations, is provided in the material safety data sheets (MSDSs). This information is supplemented, when required, by documents that specifically address known corrosion concerns and any known hazards associated with the inadvertent mixing of chemicals. In addition, the plant has documented safety-related limits for specific process parameters and ensures limit maintenance by using highly trained personnel, process controls, and monitoring and protective instrument systems.
The plant also maintains documentation that provides information about the design and construction of process equipment. Equipment information includes construction materials, design pressure, and temperature and electrical ratings. This information also provides
a basis for establishing inspection and maintenance activities, as well as for evaluating proposed process and facility changes to ensure that safety features in the process are not compromised.
Process Hazard Analysis (PHA)
The EPS has a comprehensive program to help ensure that hazards associated with the various processes are identified and controlled. Within this program, each process is systematically examined to identify hazards and ensure that adequate controls are in place to manage these hazards.
The EPS uses a combination of what if/checklist and a hazard and operatibility (HAZOP) study to perform these evaluations. These methods use a highly structured approach where process parameters such as flow and temperature are examined for deviations from their intended design. Deviation effects are considered in order to determine resulting potential hazards while preliminary recommendations for improvement are proposed.
The PHA team findings are promptly and systematically
addressed. The EPS assures that the recommendations are documented and resolved in a timely manner. This documentation includes the actions to be taken and a written schedule of completion dates. The plant also provides proof of communication with operating, maintenance, and other employees whose work assignments are in the process and who may be affected by the recommendations.
To help ensure that the process controls and/or process hazards do not eventually deviate from the original design safety features, the plant periodically updates the revalidates the hazard analysis results. These periodic reviews are conducted at least every five years by the PHA team.
The EPS maintains written procedures that address various modes of process operations, such as (1) initial startup, (2) normal operations, (3) temporary operations, (4) emergency shutdown, (5) emergency operations, (6) normal shutdown, and (7) startup following a turnaround or after an emergency shutd
own. These procedures can be used as a reference by experienced operators and provide a consistent training basis for new operators. Operating procedures are periodically reviewed and certified as current. When a process change occurs, operating procedures are revised as necessary through the management of change process.
To complement the written process operation procedures, the EPS has implemented a comprehensive training program for all employees. New employees receive job specific basic training in plant operations. Employee training includes emphasis on safety and health hazards, emergency shutdown operations, and safe work practices. Operations demonstrating adequate knowledge to safely perform duties and tasks are allowed to work independently.
Hot Work Permit
The EPS issues a hot work permit for all hot work operations conducted on or near a covered process. Procedures for issuing a hot work permit are clearly outlined in the CLECO Evangeline Safety Manual.
The EPS provides Hot Work Permit training to all plant employees. Copies of issued work permits are maintained in operations and Maintenance for a period of one-year following completion of work.
The EPS periodically uses contractors to perform maintenance or repair, turnaround, major renovations, or specialty work on or adjacent to a covered process. Because some contractors work on or near process equipment, the plant has procedures in place to ensure that contractors (1) are trained in the work practices necessary to safely perform his/her job, (2) have received and understood the training required and carry a training document card while on location, (3) follow the safety rules of the location including the safe work practices, (4) advise the plant of any unique hazards presented by the contractor, and (5) notify the facility of all illnesses and injuries that occur in the process areas.
Pre-Startup Safety Reviews (PSSRs)
The EPS conducts a PSSR for any facility
modification that requires a change in the process safety information. The purpose of the PSSR is to ensure that safety features, procedures, personnel, and equipment are approximately prepared for startup prior to placing the equipment into service. This review provides an additional check to make sure that construction and equipment are in accordance with design specification, that adequate safety, operating, maintenance, and emergency procedures are in place, and that training of each employee involved in operating the process or equipment has been completed. A standard checklist is used to document compliance.
The EPS has well-established programs, procedures and practices that are required to ensure that equipment used to process, store, or handle lightly hazardous chemicals and/or flammable gas or liquid is designed, constructed, installed, and maintained to minimize the risk of a release. Equipment examples include vessels, storage tanks, piping syste
ms, and relief and vent systems with associated emergency shutdown systems and controls (i.e., monitoring devices, sensors, alarms, and interlocks).
Maintenance personnel receive training on (1) an overview of the process, (2) a review of the process hazards, and (3) the procedures applicable to the employee's job tasks to ensure that the employees can perform the job tasks in a safe and satisfactory manner. Process equipment inspection and testing follows recognized and generally accepted good engineering practices. Equipment deficiencies that are outside of acceptable limits are corrected before further use or in a safe and timely manner when necessary means are taken to ensure safe operation.
Management of Change
The EPS has a comprehensive system to manage and document changes to all covered processes. A systematic approach is followed to control and manage facility changes in order to minimize the possibility that such changes will have an adverse impact on personnel safety,
equipment, or the environment. Employees involved in process operations and maintenance and contract employees whose job tasks might be affected by process changes are informed of and trained in the change prior to process start-up.
The EPS promptly investigates all incidents that resulted in, or reasonably could have resulted in, a fire/explosion, toxic gas release, major property damage, environmental loss, or personal injury. An incident investigation is initiated as promptly as possible to thoroughly investigate and analyze the incident. This investigation is lead by an incident investigation team consisting of those with appropriate knowledge and experience in the process. The findings and recommendations made by the incident investigation team are promptly addressed and resolved in a timely manner. The final resolution of each finding or recommendation is documented, and the investigation results are reviewed with all employees (including contractor
s) who could be affected by the findings.
Emergency Planning and Response
The EPS retains a written site specific formal emergency response plan which includes the designated actions the company and all personnel will take to ensure personal safety from fire and other emergencies. The plan outlines actions that company technicians and contract employees are to take when there is an unwanted release of highly hazardous chemicals. The intent of this plan is to facilitate the prompt evacuation of employees when necessary and to account for all personnel. The emergency plan also includes procedures for handling small releases.
To help ensure that the accident prevention program is properly functioning, the EPS periodically conducted an audit to determine whether the procedures and practices required by the accident prevention program are being implemented. Compliance audits are conducted at least every three years. The audit team includes those knowledgeable in t
he process, operations personnel, and at least one person trained in audit techniques and practices. The audit team develops findings and corrective actions are tracked until they are complete. The final resolution of each finding is documented, and the two most recent audit reports are retained.