Onondaga Cogeneration Facility - Executive Summary
Risk Management Plan Pursuant to 40 CFR 68(G) |
Onondaga Cogeneration Limited Partnership
June 11, 1999
Onondaga Cogeneration Limited Partnership owns and operates a cogeneration facility in Syracuse, New York (Onondaga Cogeneration or OCLP facility) which is subject to U.S. EPA regulations governing Accidental Release Prevention (ARP) Requirements: Risk Management Programs under Section 112(r) of the Clean Air Act (40 CFR Part 68). This Risk Management Plan (RMP) has been developed in accordance with the requirements specified under 40 CFR Part 68, Subpart G. This RMP certifies that Onondaga Cogeneration Limited
Partnership has instituted a Risk Management Program at the OCLP Syracuse, New York facility that is in compliance with U.S. EPA ARP requirements.
The RMP includes an Executive Summary and Data Elements following the format published by U.S. EPA. In addition to identifying the applicable corporate policies and risk management systems, identifies a set of worst case and alternative release scenarios, the potential off-site consequences of those releases, and the facility's five-year accidental release history. This RMP certifies that prevention and emergency response programs are in place so as to minimize risks to workers and the potentially affected public.
2. ACCIDENTAL RELEASE PREVENTION POLICIES
2.1. Risk Management Policies
It is the policy of OCLP management to implement the requirements of the Risk Management Program (RMP) in accordance with the USEPA regulations under 40 CFR Part 68. The objective of this program is to minimize
the risk of a release of a hazardous material and, if a release were to occur, to minimize the potential impact to OCLP employees, the public and the environment.
This objective will be accomplished by utilizing good operating procedures, providing appropriate training to all employees, and coordinating response activities, as necessary, with the local emergency response providers. OCLP's management is committed to providing the resources necessary to implement this policy. Further, the OCLP management recognizes that it has a duty to protect its employees and neighbors from the effects of all dangerous chemicals.
2.2. Risk Management System
The OCLP facility has developed a management system to implement and maintain compliance with the ARP Program and related chemical safety and emergency response programs. At the OCLP facility, the Plant Manager has primary responsibility for implementing and ensuring compliance with the ARP Program. Other in
dividual employees will assist the Plant Manager with various aspects of the program as required.
3. PROCESSES AND SUBSTANCES SUBJECT TO 40 CFR 68
3.1. Facility Overview
The OCLP facility is a combined-cycle cogeneration facility which produces electric power for sale to the Niagara Mohawk Corporation and process steam to its host facility (Crucible Specialty Metals Products). The OCLP facility consists of two General Electric gas turbines rated at 45 and 23 Megawatts (MW) of electric output. Waste heat from the turbine exhaust gases is
passed through a heat recovery steam generator to generate steam. Natural gas is the facility's primary fuel, with No. 2 distillate oil used as a backup fuel.
The combustion turbine design includes Best Available Control Technology (BACT) for the control of carbon monoxide and nitrogen oxides. Emissions of carbon monoxide are controlled through the use of an oxidation catalyst in Turbine No. 1. Emissions
of nitrogen oxides are controlled with a combination of water injection and Selective Catalytic Reduction (SCR). Water injection is used to cool the flame temperature in Turbine Nos. 1 and 2 thus inhibiting the formation of "thermal NOx". Nitrogen oxide emissions are further reduced through the application of SCR. SCR is a process which involves the post-combustion removal of nitrogen oxides from the combustion flue gas with a catalytic reactor. In the SCR process, aqueous ammonia, which is injected into the turbine exhaust gas stream, reacts with the nitrogen oxides and oxygen in the exhaust gas stream to form nitrogen and water.
It is this aqueous ammonia (CAS No. 7664-41-7) which is a regulated substance under 40 CFR 68 and present at the site in amounts greater than the threshold quantity.
3.2. Process Description
Ammonia is present at the facility in the form of an aqueous solution in concentrations ranging up to 30 percent. The
aqueous ammonia is delivered to the site via tank truck and stored in an above ground tank with a maximum capacity of 18,000 gallons (40,554 pounds). The tank is surrounded by a dike of sufficient volume to completely contain and spill from the storage tank. A piping system (both above and below ground) is used to deliver the ammonia to the combustion turbines. Prior to injection into the combustion turbine exhaust gas stream, the aqueous ammonia is vaporized and injected as a gas.
3.3. Program Level Identification
The EPA Risk Management Regulation identifies three levels of requirements defined as "programs". EPA recognizes that some regulated processes would not pose an off-site hazard in the event of an accidental release. Such processes are classified as Program 1. Program 1 is applicable to any process for which it can be demonstrated that the public would not be adversely affected by a release. Thus, to qualify for Program 1, a facilit
y with a regulated toxic chemical needs to meet two criteria.
- no release over the most recent 5-year period has resulted in off-site injury or environmental damage; and
- dispersion modeling demonstrates that a worst-case release (as defined by the regulation) will not result in concentrations at public receptors that exceed the toxic endpoint.
The Onondaga Cogeneration facility has not had an accident or release involving the aqueous ammonia during the history of the facility. However, the worst-case release, as defined by the regulation, results in concentrations at public receptors just beyond the facility fenceline that exceed the toxic endpoint. Therefore, the aqueous ammonia process is not eligible for Program 1.
Program 2 and 3 are applicable to processes that do not qualify for Program 1. Program 3 applies to processes that are subject to Occupational Safety and Health Administration (OSHA) Process Safety Management Standard (PSM) or lis
ted among nine North American Industrial Classification System (NAICS) codes. All other processes are subject to Program 2. The aqueous ammonia process is not subject to the OSHA PSM standard, therefore the process is subject to Program 2.
4. HAZARD ASSESSMENT
For the purposes of developing and maintaining adequate Risk Management Plans, the EPA has defined in its governing rules and guidance a series of modeling methods and assumptions, which are to be used as administrative guides for planning purposes. In order to standardize and simplify the many factors that can potentially occur in an accidental release situation, some of these assumptions may not take into account the available preventive measures or mitigation methods that could diminish or
even eliminate the implied risks that are suggested by "worst-case" analyses. For that reason, both the results for the standardized "worse-cases" defined by th
e EPA methods and a set of alternative cases which are believed by the facility to more realistically represent situations that may possibly, but rarely, occur within the lifetime of the facility are also presented. The sections of the Risk Management Plan which discuss both worst-case, and alternative cases, are meant to provide the data
necessary to develop and evaluate possible improvements in the overall safety programs of the facility's RMP program.
The worst-case release scenario, as defined by 40 CFR Part 68, is a sudden release of the maximum amount of a stored regulated substance from the largest single vessel. Toxic liquids, such as aqueous ammonia, are assumed to spill instantaneously and spread to a depth of 1 cm in an undiked area or to cover a diked area. The duration of the release is based on the evaporation rate of the toxic liquid and the amount spilled. Only passive mitigation (e.g., dikes, enclosures) and administrat
ive controls may be
accounted for in the evaluation.
EPA has established "toxic endpoints" for various chemicals based on the American Industrial Hygiene Association (ACGIH) Emergency Response Planning Guideline, Level 2 (ERPG-2), which protects
individuals from health-threatening or escape-impairing injury. The ERPG-2 is defined as:
"the maximum airborne concentration below which it is
believed that nearly all individuals could be exposed
for up to 1 hr without experiencing or developing
irreversible or other serious health effects or
symptoms which could impair an individual's ability to
take protective action."
Given that the worst-case is a 10-minute release duration with a 10-minute concentration averaging time, the actual hazard zone is typically overestimated by the ERPG-2. Within such a time period there are a number of emergency measures that can reduce or eliminate exposures to levels this high for an
interval much shorter than an hour.
Under Section 68.22 (e), the RMP rule identifies "surface roughness" as a parameter to be specified in the hazard assessment. The surface roughness affects the amount of dispersion that occurs within a released plume and influences the distance to toxic endpoint. The surface roughness used in determining the distance to toxic endpoint should be characteristic of the transport path of the plume from the release point to the endpoint distance. `Urban' surface roughness indicates areas where there are many obstacles, such as industrial buildings or trees. `Rural' indicates that there are
no buildings in the immediate vicinity of a facility and that the terrain is generally flat and unobstructed.
In the immediate vicinity of the aqueous ammonia storage tank, the aerodynamic surface roughness is `urban' in nature, due to the buildings, tanks and structures at the site. Urban disp
ersion was therefore used in this analysis.
At the OCLP facility, the regulatory prescribed worst-case release is an instantaneous spill of the entire contents of the aqueous ammonia storage tank. The spill area, and thus the rate of evaporation is limited by a dike with a maximum surface area of approximately 433 square feet. The aqueous ammonia is stored at ambient temperature, which for purposes of this worst-case analysis was assumed to be at the highest daily average temperature as historically measured at the nearest National Weather Service station.
The EPA's Risk Management Program Guidance for Wastewater Treatment Plants (EPA 1998) was utilized to determine distance to the toxic endpoint for the worst-case release. This guidance document contains methodologies to estimate the toxic endpoint distances for worst-case releases of aqueous ammonia from a diked storage tank. The equations contained in the EPA guidance docum
ent incorporate the prescribed worst-case modeling assumptions i.e., stable atmosphere with limited dispersion (F stability and 1.5 m/sec wind speed).and provide for corrections for storage concentration and storage temperature. For purposes of the worst-case release, the maximum concentration of 30
percent and maximum historical daily daily average temperature were assumed.
The results of the worst-case release are documented in the Data Elements section. The distance to the less than 0.09 miles or approximately 465 feet. Within this distance are two small industrial operations which qualify as "public receptors". No schools, hospitals, residences, or recreational areas are within the worst-case toxic endpoint distance.
4.2. Alternative Releases of Toxic Substances
Alternative releases are intended to represent release scenarios that have a greater likelihood of occurrence than a worst-case release. Alternative releases do not necess
arily represent the types of releases that the hazards analysis and/or accident history indicate would be most frequent, but rather a release that is somewhat more likely than the worst-case release and that generally still has the potential to affect off-site receptors. In accordance with the RMP rule, alternative releases are modeled under typical (rather than worst-case) dispersion conditions. The EPA OCAG default dispersion conditions are neutral atmosphere, with dispersion neither enhanced nor limited (D stability and 3 m/sec wind speed). Unlike the worst-case release (for which an instantaneous spill or 10-minute ground-level gas release is
assumed), alternative scenarios can account for the actual release configuration, and account for both active and passive mitigation.
The OCLP facility performed a thorough review of the aqueous ammonia process utilizing engineering plans, operational experience, and maintenance records, in
order to identify potential alternative release scenarios. Each identified alternative release scenario was evaluated to determine the potential for to affect offsite public receptors. Based on this analysis, no alternative release was identified which would result in a toxic endpoint distance beyond the facility fenceline. This analysis included the regulatory defined worst-case scenario (i.e., sudden release of the maximum amount of aqueous ammonia in the storage tank) which is an extremely improbably event.
The selected alternative release scenario was a tank filling accident where the transfer hose disconnects between the delivery truck and the storage tank. The design of the truck delivery area is sloped such that any spill in this area will drain directly into the tank dike area. For a release into the diked area, as would occur in this situation, the maximum endpoint distance will occur when the surface area of a pool formed
by the total quantity of solution spilled to the ground in the absence of the dike would be greater than the diked surface area. Based on the dike area, this amount is approximately 105 gallons. Amounts greater than this will not result in larger endpoint distances.
The distance to the toxic endpoint for the alternative release was estimated using the EPA's Risk Management Program Guidance for Wastewater Treatment Plants (EPA 1998). The estimated distance to the toxic endpoint for this worst-case alternative release scenario is less than 0.05 miles or approximately 250 feet. This distance is less than the distance to the facility fenceline, therefore, there are no public receptors affected by a worst-case alternative release.
5. ACCIDENT PREVENTION PROGRAM
The elements of the Program 2 Prevention Program are safety information, hazard review, operating procedures, training, maintenance, incident investigation, and comp
liance audits. Each is discussed briefly below.
5.1. Safety Information
The facility keeps a variety of technical documents that are used to help maintain safe operation of the processes. These documents address chemical properties and associated hazards, limits for key process parameters, specific chemical inventories, and equipment design basis/configuration information.
5.2. Hazard Review
The facility used the What-If/Checklist analysis technique to perform the evaluation of the regulated systems. The analyses were conducted using a team of people who have operation and maintenance experience as well as engineering expertise. This team identified and evaluated hazards of the process, accident prevention and mitigation measures, and made suggestions for additional prevention and/or mitigation measures when the team believed such measures were necessary. The recommendations from the team will be tracked to completion.
5.3. Operating Pr
The facility maintains written procedures that address various modes of process operations, such as: unit startup, operations, shutdown, and loading. These procedures form the basis of the operator training and are periodically reviewed and annually certified as current and accurate.
To complement the written procedures for process operations, the facility has a comprehensive training program for all employees involved in operating the affected process. A combination of classroom and on-the-job training and observation is used to ensure the person has developed the necessary skills. All operators receive refresher training each three years on the complete process to ensure that their skills and knowledge are maintained at an acceptable level. The training is documented for each operator.
The facility has an established maintenance program for maintaining the mechanical integrity of th
e process equipment. This program includes daily visual inspection of all equipment. All mechanical equipment are maintained per the manufacturer's recommended maintenance schedules.
5.6. Incident Investigation
The facility has in place an incident investigation procedure for the complete investigation of all incidents at the facility. These procedures include not only the RMP affected substance, aqueous ammonia, but all environmental incidents at the facility. The investigation team documents its findings, develops
recommendations to prevent a recurrence, and forwards these results to plant management for resolution. Corrective actions taken in response to the investigation team's findings and recommendations are tracked until they are completed.
5.7. Compliance Audits
Compliance audits for the accidental release prevention program elements will be conducted every three years. The audit team will develop findings that are forwarded to
plant management for resolution. Corrective actions taken in response to the audit team's findings will be tracked until they are completed. The final resolution of each finding will be is documented in an audit report.
6. FIVE YEAR ACCIDENT HISTORY
In conjunction with the OCLP facility's existing emergency response and incident investigation procedures, there is a standard management practice that requires immediate internal reporting of unusual events, including those in which any abnormal emission of regulated chemicals is observed or suspected. The incident information is reviewed by supervisory staff and a determination is made as to whether a reportable quantity of any chemical listed as requiring reports to regulatory authorities is involved. If so, the appropriate authorities are promptly notified.
During the past 5 years there has been no accident involving aqueous ammonia
that qualifies for reporting under 40 CFR Part 68.
7. EMERGENCY RESPONSE PROGRAM
The OCLP facility has coordinated potential emergency response activities with the Onondaga County LEPC. Procedures are in place to ensure that the LEPC is prepared to respond to an emergency at the facility. An emergency action plan is in place to ensure that the LEPC is notified promptly in the event of an emergency and to ensure the safety of the employees.
Facility personnel are not expected to "respond" to an emergency as defined by the OSHA HAZWPOPER Standard. Facility personnel are expected to perform incidental response activities to minimize incidental or minor releases.
8. PLANNED CHANGES TO IMPROVE SAFETY
The OCLP facility, management recognizes that process safety is not only critical to facility operations but also for the safety of the employees and the community. The management system, which has been implemented at the OCLP facility, is d
esigned to ensure that process safety is implemented on an ongoing, daily basis.
As a result of the process hazards analysis, additional maintenance procedures were identified to improve the effectiveness of the existing mitigation system. These will be developed and implemented in an expeditious manner.