Williams Midstream NGL Inc.Conway Fractionator - Executive Summary
Facility Overview |
In this process facility a demethanized natural gas liquid is fractionated to produce end user products of ethane, propane, iso-butane, normal butane and natural gasoline. All of these are considered hazardous by the EPA. The same properties that make these products valuable as fuel and chemical resources also make it necessary to observe certain safety precautions in handling them. To prevent unnecessary human exposure, to reduce the threat to personal health to workers and to reduce the threat to nearby members of the community, it is policy to adhere to all applicable federal and state rules and regulations.
Plant safety depends upon the manner in which we handle these products combined with the safety devices inherent in the design of this facility combined with the safe handling procedures that we use and the training of our personnel.
Accidental Release Prevention and Emergency Response Policies
This facility has implemented all 14 elements of OSHA's 1910.119
Process Safety Management regulation to insure facility and process safety. The emergency response program is based on OSHA and EPA's emergency response guidelines. The emergency response plan includes procedures for notification of the local fire authority and notification of any potentially affected neighbors.
The primary function of this facility is to fractionate the demethanized NGL's (Natural Gas Liquids) into purity products, which are then sent to a pipeline facility for distribution to customers. All the demethanized NGL is received from the pipeline source and stored in salt solution caverns. The NGL is then injected into the process where the products are separated by controlling temperatures and pressures on the different vessels involved in the process, thereby controlling the composition of the end products.
Some impurities contained in these products are removed by treating with non-hazardous chemicals, by EPA's standards. Heat for th
e process is provided by heat medium oil and direct fired furnaces fueled by natural gas. Access to the site is restricted to authorized facility employees, authorized management personnel and authorized contractors.
The regulated substances handled at this facility include, demethanized NGL's, ethane, propane, iso-butane, normal butane and natural gasoline.
The maximum quantities of these listed hazards are as follows:
Demethanized NGL: 127,000,000 pounds
Ethane: 38,000 pounds
Propane: 86,000 pounds
Iso-Butane: 96,000 pounds
Normal Butane: 55,000 pounds
Natural Gasoline: 23,000 pounds
Worst Case Scenario/Alternative Release Scenario
The Worst Case Scenario, calculated using ARCHIE's and RMPComp, consists of one of the storage caverns dischar
ging to the atmosphere through an 8" pipe at the well head and it has potential for offsite consequences to several similar businesses and one residence. To prevent this there is an Emergency Shutdown System on the product and brine lines of the cavern that should mitigate a release from these caverns by closing valves on the lines.
The Alternative Release Scenario was based on a product release caused by a fitting failure on a process heat exchanger. No passive or active mitigation measures were taken into account for this release.
Emergency Response Program
This Fractionator complies with EPA's Accidental Release Prevention Rule and with all applicable state codes and regulations. This facility was designed and constructed in accordance with NFPA-58. In the past five years there have been no accidental releases of any hazardous substances with off-site consequences or significant loss to the facility.
This facility's emergency response program is based upon OSHA's emergency res
ponse guidelines from 1910.119(n). This program has been reviewed with the McPherson County (LEPC) Local Emergency Planning Committee, the Windom Volunteer Fire Department and McPherson Fire Department. A representative group from the Windom Volunteer Fire Department visited this facility on March 16, 1994. The emergency contact phone numbers listed are to 24 hour-manned locations that are trained in the proper procedures to implement an emergency response.
Planned Safety Improvements
This facility is in the process of improving the facility's ESD system to include critical valves in the treating section in addition to upgrading and improving the gas detection system inside the facility.