Anschutz Ranch East Gas Plant - Executive Summary
Executive Summary |
ACCIDENTAL RELEASE PREVENTION AND RESPONSE POLICIES
The Anschutz Ranch East Gas Plant has a long-standing commitment to worker and public safety. This commitment is demonstrated by the resources invested in accident prevention, such as training personnel and considering safety in the design, installation, operation, and maintenance of our processes. Our policy is to implement reasonable controls to prevent foreseeable releases of regulated substances. However, if a release does occur, trained personnel will respond to control and contain the release.
DESCRIPTION OF THE STATIONARY SOURCE AND REGULATED SUBSTANCES
The Anschutz Ranch East Gas Plant, located near Evanston, Wyoming, operates a variety of processes to produce petroleum products, including natural gas, natural gas liquids, and condensate from the produced well stream. In addition, the plant operates a variety of refrigeration and support processes which use ammonia, methane, and propane as the refri
gerant. The Anschutz Ranch East Gas Plant has several regulated flammables from methane through pentane. These compounds may be present in both hydrocarbon mixtures and as essentially pure compounds. The only regulated toxic at the facility is anhydrous ammonia used as a refrigerant in a gas chilling system. Hydrogen sulfide is not present in the facility in any concentrations or volumes subject to regulation or of concern.
All of the covered processes in the facility are designated as "Program 3" under this Risk Management Plan and handled accordingly.
OFFSITE CONSEQUENCE ANALYSIS RESULTS
Toxic Release Scenarios
The worst-case scenario (WCS) associated with a release of toxic substances is a catastrophic failure of the largest vessel (ammonia receiver) in the ammonia based refrigeration system. This scenario assumes the release of the entire vessel contents (39,713 pounds) of anhydrous ammonia during a 10 minute period. Although we have numerous controls to prevent such r
eleases and to manage their consequences, no credit for administrative controls or passive mitigation measures was taken into account in evaluating this scenario. The dispersion of the released ammonia was modeled using HEGADAST 3+ incorporating the conservative assumptions of a liquid release which flashes to an aerosol vapor cloud and stable/low speed wind conditions (worst case meteorological conditions). The maximum distance to the regulatory toxic endpoints of 200 ppm and 1000 ppm was predicted by the modeling to be 1.2 miles and 0.4 miles respectively.
The alternative release scenario (ARS) for anhydrous ammonia was chosen as the complete severing of a 2" process pipe connected to the liquid phase of the same ammonia receiver vessel. Again, the entire vessel contents of 39,713 pounds was released through the broken pipe but over the time period necessary to empty the vessel through a 2" orifice (~126 minutes). Both worst case meteorological conditions (F stability and 1.0
m/s wind speed) and typical calm daytime meteorological conditions (D stability and 3 m/s wind speed) were modeled. No mitigation or control measures were taken into account in evaluating this scenario. The maximum distance to the toxic endpoints of 200 ppm and 1000 ppm for the worst case meteorological conditions was 1.7 miles and 0.3 miles respectively. The maximum distance to the toxic endpoints of 200 ppm and 1000 ppm for the typical calm daytime meteorological conditions was 0.4 miles and 0.2 miles respectively.
Flammable Release Scenarios
The WCS associated with the release of flammable substances at the Anschutz Ranch East Gas Plant is the release of the full inventory of one of the NGL storage bullets followed by a vapor cloud explosion. This is an instantaneous release of 282,487 pounds of a mixed NGL product. The EPAs RMP-Comp model was used with the default worst case meteorological conditions of F stability and 1.5 meters/sec wind speed. The maximum distance to
the 1-psi overpressure endpoint for the WCS is 0.5 miles. Although we have numerous controls to prevent such releases and to manage their consequences. no credit for control or mitigation measures was taken into account in evaluating this WCS.
The ARS for flammable substances was chosen to be the complete severing of a 2" process pipe on the bottom (liquid portion) of the storage bullet followed by a vapor cloud explosion. A conservative assumption that the entire inventory was propane was made due to the models inability to handle mixtures in the alternative scenario mode. Propane was chosen as the substance which has the greatest overpressure zone associated with this type of release. The EPAs RMP-Comp model was used to determine the release rate of 11,800 lbs/min and the maximum distance to the 1-psi overpressure endpoint. Meteorological conditions used were those incorporated into the model as defaults for alternative scenario evaluation. The release was assumed to pers
ist for 24 minutes duration at the initial flow rate which is the time necessary to release the entire vessel contents through the 2 inch pipe. The maximum distance to the 1-psi overpressure endpoint for this ARS is 0.3 miles. No control or mitigation activities were considered in evaluating this scenario.
GENERAL ACCIDENTAL RELEASE PREVENTION PROGRAM
The following is a summary of the accident prevention program in place at the plant. Because processes at the gas plant that are regulated by the Environmental Protection Agencys (EPAs) risk management program (RMP) regulation are also subject to the Occupational Safety and Health Administrations (OSHAs) process safety management (PSM) standard, this summary addresses each of the OSHA PSM elements and describes the management system in place to implement the accident prevention program.
The Anschutz Ranch East Gas Plant encourages employees to participate in all facets of process safety management and
accident prevention. Examples of employee participation range from updating and compiling technical documents and chemical information to participating as a member of a process hazard analysis (PHA) team. Employees have access to all information created as part of the gas plant accident prevention program. Specific ways that employees can be involved in the accident prevention program are documented in an employee participation plan that is maintained at the gas plant and addresses each accident prevention program element. In addition, the gas plant has a number of initiatives under way that address process safety and employee safety issues. These initiatives include forming teams to promote both process and personal safety. The teams typically have members from various areas of the plant, including operations, maintenance, engineering, and plant management.
Process Safety Information
The Anschutz Ranch East Gas Plant keeps a variety of technical documents that are used to he
lp maintain safe operation of the processes. These documents address chemical properties and associated hazards, limits for key process parameters and specific chemical inventories, and equipment design basis/configuration information. Up-to-date process safety information is maintained on an ongoing basis. The reference documents are readily available at the plant location
Chemical-specific information, including exposure hazards and emergency response/exposure treatment considerations, is provided in material safety data sheets (MSDSs). This information is supplemented by documents that specifically address known corrosion concerns and any known hazards associated with the inadvertent mixing of chemicals. For specific process areas, the gas plant has documented safety-related limits for specific process parameters (e.g., temperature, level, composition) in a Key Process Parameter Document. The gas plant ensures that the process is maintained within these limits using process c
ontrols and monitoring instruments, highly trained personnel, and protective instrument systems (e.g., automated shutdown systems).
The gas plant also maintains numerous technical documents that provide information about the design and construction of process equipment. This information includes materials of construction, design pressure and temperature ratings, and electrical rating of equipment. This information, in combination with written procedures and trained personnel, 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 Anschutz Ranch East Gas Plant 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 a
re in place to manage these hazards.
The Anschutz Ranch East Gas Plant primarily uses the hazard and operability (HAZOP) analysis technique to perform these evaluations. HAZOP analysis is recognized as one of the most systematic and thorough hazard evaluation techniques. The analyses are conducted using a team of people who have operating and maintenance experience as well as engineering expertise. This team identifies and evaluates hazards of the process as well as accident prevention and mitigation measures, and the team makes suggestions for additional prevention and/or mitigation measures when the team believes such measures are necessary.
The PHA team findings are forwarded to local and corporate management for resolution. Mitigation options in response to PHA team findings are tracked until they are completed. The final resolution of each finding is documented and retained.
To help ensure that the process controls and/or process hazards do not eventually deviate sign
ificantly from the original design safety features, the plant periodically updates and revalidates the hazard analysis results. These periodic reviews are conducted at least every 5 years and will be conducted at this frequency until the process is no longer operating. The results and findings from these updates are documented and retained. Once again, the team findings are forwarded to management for consideration, and the final resolution of the findings is documented and retained.
The Anschutz Ranch East Gas Plant maintains written procedures that address various modes of process operations, such as (1) unit startup, (2) normal operations, (3) temporary operations, (4) emergency shutdown, (5) normal shutdown, and (6) initial startup of a new process. These procedures can be used as a reference by experienced operators and provide a basis for consistent training of new operators. These procedures are periodically reviewed and annually certified as curren
t and accurate. The procedures are kept current and accurate by revising them as necessary to reflect changes made through the management of change process.
In addition, the Anschutz Ranch East Gas Plant maintains a Key Process Parameter Document that provides guidance on how to respond to upper or lower limit exceedances for specific process or equipment parameters. This information, along with written operating procedures, is readily available to operators in the process unit and for other personnel to use as necessary to safely perform their job tasks.
To complement the written procedures for process operations, the Anschutz Ranch East Gas Plant has implemented a comprehensive training program for all employees involved in operating a process. New employees receive basic training in gas plant operations if they are not already familiar with such operations. After successfully completing this training, a new operator is paired with a senior operator to learn proce
ss-specific duties and tasks. After operators demonstrate (e.g., through tests, skills demonstration) having adequate knowledge to perform the duties and tasks in a safe manner on their own, they can work independently. In addition, all operators periodically receive refresher training on the operating procedures to ensure that their skills and knowledge are maintained at an acceptable level. This refresher training is conducted at least every 3 years. All of this training is documented for each operator, including the means used to verify that the operator understood the training.
The Anschutz Ranch East Gas Plant uses contractors to supplement its workforce during periods of increased maintenance or construction activities. Because some contractors work on or near process equipment, the gas plant has procedures in place to ensure that contractors (1) perform their work in a safe manner, (2) have the appropriate knowledge and skills, (3) are aware of the hazards i
n their workplace, (4) understand what they should do in event of an emergency, (5) understand and follow site safety rules, and (6) inform gas plant personnel of any hazards that they find during their work. This is accomplished by providing contractors with (1) a process overview, (2) information about safety and health hazards, (3) emergency response plan requirements, and (4) safe work practices prior to their beginning work. In addition, the Anschutz Ranch East Gas Plant evaluates contractor safety programs and performance during the selection of a contractor. Gas Plant personnel periodically monitor contractor performance to ensure that contractors are fulfilling their safety obligations.
Pre-startup Safety Reviews (PSSRs)
The Anschutz Ranch East Gas Plant conducts a PSSR for any new facility or 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
appropriately prepared for startup prior to placing the equipment into service. This review provides one additional check to make sure construction is in accordance with the design specifications and that all supporting systems are operationally ready. A PSSR involves field verification of the construction and serves a quality assurance function by requiring verification that accident prevention program requirements are properly implemented.
The Anschutz Ranch East Gas Plant has well-established practices and procedures to maintain pressure vessels, piping systems, relief and vent systems, controls, pumps and compressors, and emergency shutdown systems in a safe operating condition. The basic aspects of this program include: (1) conducting training, (2) developing written procedures, (3) performing inspections and tests, (4) correcting identified deficiencies, and (5) applying quality assurance measures. In combination, these activities form a system that m
aintains the mechanical integrity of the process.
Maintenance personnel receive training on (1) an overview of the process, (2) safety and health hazards, (3) applicable maintenance procedures, (4) emergency response plans, and (5) applicable safe work practices to help ensure that they can perform their jobs in a safe manner. Written procedures help ensure that work is performed in a consistent manner and provide a basis for training. Inspections and tests are performed to help ensure that equipment functions as intended and to verify that equipment is within acceptable limits (e.g., adequate wall thickness for pressure vessels). If a deficiency is identified, employees will correct the deficiency before placing the equipment back into service (if possible), or a management of change team will review the use of the equipment and determine what actions are necessary to ensure the safe operation of the equipment.
Another integral part of the mechanical integrity program is qual
ity assurance. The Anschutz Ranch East Gas Plant incorporates quality assurance measures into equipment purchases and repairs. This helps ensure that new equipment is suitable for its intended use and that proper materials and spare parts are used when repairs are made.
Safe Work Practices
The Anschutz Ranch East Gas Plant has long-standing safe work practices in place to help ensure worker and process safety. Examples of these include (1) control of the entry/presence/exit of support personnel, (2) a lockout/tagout procedure to ensure isolation of energy sources for equipment undergoing maintenance, (3) a procedure for safe removal of hazardous substances before process piping or equipment is opened, (4) a permit and procedure to control spark or ignition-producing activities (i.e., hot work), and (5) a permit and procedure to ensure that adequate precautions are in place before entry into a confined space. These procedures (and others), along with training of affected personn
el, form a system to help ensure that operations and maintenance activities are performed safely.
Management of Change
The Anschutz Ranch East Gas Plant has a comprehensive system to manage changes to all covered processes. This system requires that changes to items such as process equipment, chemicals, technology (including process operating conditions), procedures, and other facility changes be properly reviewed and authorized before being implemented. Changes are reviewed to (1) ensure that adequate controls are in place to manage any new hazards and to (2) verify that existing controls have not been compromised by the change. Affected chemical hazard information, process operating limits. and equipment information, as well as procedures, are updated to incorporate these changes. In addition, operating and maintenance personnel are provided any necessary training on the change.
The Anschutz Ranch East Gas Plant promptly investigates all incidents t
hat resulted in, or reasonably could have resulted in, a fire/explosion, toxic gas release, major property damage, environmental loss, or personal injury, The goal of each investigation is to determine the facts and develop corrective actions to prevent a recurrence of the incident or a similar incident. The investigation team documents its findings, develops recommendations to prevent a recurrence, and forwards these results to gas plant management for resolution. Corrective actions taken in response to the investigation teams findings and recommendations are tracked until they are complete. The final resolution of each finding or recommendation is documented, and the investigation results are reviewed with all employees (including contractors) who could be affected by the findings. Incident investigation reports are retained for at least 5 years so that the reports can be reviewed during PHAs and PHA revalidations.
To help ensure that the accident preventi
on program is functioning properly, the Anschutz Ranch East Gas Plant periodically conducts 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 3 years. Both hourly and staff personnel participate as audit team members. The audit team develops findings that are forwarded to gas plant management for resolution. Corrective actions taken in response to the audit teams findings are tracked until they are complete. The final resolution of each finding is documented, and the two most recent audit reports are retained.
CHEMICAL-SPECIFIC PREVENTION STEPS
The processes at the Anschutz Ranch East Gas Plant have hazards that must be managed to ensure continued safe operation. The following is a description of existing safety features applicable to prevention of accidental releases of regulated substances in the facility.
Universal Prevention Activities
prevention program summarize previously is applied to all RMP-covered processes at the Anschutz Ranch East Gas Plant. Collectively, these prevention program activities help prevent potential accident scenarios that could be caused by equipment failures and human errors.
Specialized Safety Features
The Anschutz Ranch East Gas Plant has safety features on many units to help (1) contain/control a release, (2) quickly detect a release, and (3) reduce the consequences of (mitigate) a release. The following types of safety features are used in the covered processes:
1. Process area detectors with alarms.
1. Process relief valves that discharge to a flare to capture and incinerate episodic releases.
2. Valves to permit isolation of the process (manual or automated) and to prevent backflow.
3. Automated shutdown systems.
4. Curbing or diking to contain liquid releases.
5. Selective redundant equipment and instrumentation (e.g
., backup pumps).
6. Atmospheric relief devices.
7. Process interlocks.
1. Trained emergency response personnel.
2. Personal protective equipment (e.g., chemical protective clothing, self-contained breathing apparatus).
FIVE-YEAR ACCIDENT HISTORY
The Anschutz Ranch East Gas Plant has an excellent record of accident prevention over the past 5 years. There have been no incidents with off-site impacts during the previous 5 years. been Incidents are reviewed to determine ways to prevent similar incidents from recurring.
EMERGENCY RESPONSE PROGRAM INFORMATION
The Anschutz Ranch East Gas Plant maintains a written emergency response program, which is in place to protect worker and public safety as well as the environment. The program consists of procedures for responding to a release of a regulated substance, including the possibility of a fire or explosion if a flammable substance is accidentally released. The procedures address all aspects of emerge
ncy response, including proper first aid and medical treatment for exposures, evacuation plans and accounting for personnel after an evacuation, notification of local emergency response agencies and the public if a release occurs, and post incident cleanup and decontamination requirements. In addition, the plant has procedures that address maintenance, inspection, and testing of emergency response equipment, as well as instructions that address the use of emergency response equipment. Employees receive training in these procedures as necessary to perform their specific emergency response duties. The emergency response program is updated when necessary based on modifications made to gas plant processes or other Anschutz Ranch East Gas Plant facilities. The emergency response program changes are administered through the MOC process, which includes informing and/or training affected personnel in the changes.
The overall emergency response program for the Anschutz Ranch East Gas Pla
nt is coordinated with the Local Emergency Planning Committee (LEPC). This coordination includes periodic meetings of the committee, which includes local emergency response officials, local government officials, and industry representatives. The Anschutz Ranch East Gas Plant has around-the-clock communications capability with appropriate LEPC officials and emergency response organizations (e.g., fire department). This provides a means of notifying the public of an incident, if necessary, as well as facilitating quick response to an incident. In addition to periodic LEPC meetings, the Anschutz Ranch East Gas Plant conducts periodic emergency drills that involve the LEPC and emergency response organizations.
PLANNED CHANGES TO IMPROVE SAFETY
The Anschutz Ranch East Gas Plant resolves all findings from PHAs, some of which result in modifications to the process. The following types of changes are planned over the next few years in response to PHA, safety audit, and incident investig
7 Confirmation of PSV design and capabilities
7 Inspection of dead-leg areas for potential accelerated corrosion
7 Confirmation of vessel ratings
7 Re-evaluate piping supports from historical data and observation