Carpenter Co. - Powell Plant - Executive Summary
EXECUTIVE SUMMARY |
Accidental Release Prevention and Emergency Response Policies:
Carpenter Co. is totally committed to the safe operation of its Roger W. Powell chemical production facility. Engineering safeguards and safety factors have been incorporated throughout the processes employed and have been reviewed in detail as part of the Process Safety Management program. Additionally, senior management has and will continue to ensure that resources are available for the materials, equipment, and training required for safe operation of the facility. Facility safety is a team goal which is successfully achieved through the combined efforts of each individual onsite and the commitment of senior management.
Facility and Regulated Substances Handled:
The Carpenter Co., Roger W. Powell Plant, located at 11002 Choate Rd., Pasadena, Texas, manufactures polyether polyols and prepares blends of polyether polyols with various other materials for internal company use and for external sale.
The first polyether polyol production unit at the facility, the P-1 Unit, was started up in 1973, and since that time three additional polyether polyol production units, the P-2, P-3 and P-4 Units and a blending facility have been added. Approximately 80 Carpenter Co. personnel work at the facility on a full-time basis.
The polyether polyol production units are designed to produce batch quantities of various low vapor pressure polyether alcohols. Production of a typical polyether polyol involves the reaction of ethylene oxide and/or propylene oxide with a starter material such as glycerine. Ethylene oxide and propylene oxide are the regulated substances in these units.
Ethylene oxide is supplied to the plant by railcar to three closed, nitrogen-padded and externally-refrigerated pressure vessels. Propylene oxide is supplied via pipeline and/or railcar and/or tank truck to three closed, nitrogen-padded pressure vessels.. Both ethylene oxide and propylene oxide are fed via pump
from these storage vessels to four closed reaction vessels where they are reacted with various starter materials.
For the purposes of the Risk Management Plan, the four polyol production units have been grouped into three processes. The P-1 and P-2 polyol production units have been grouped together into one process as they share the same ethylene oxide and propylene oxide storage vessels. The P-3 and P-4 polyol production processes each have their own ethylene oxide and propylene oxide storage vessels and are considered separate processes.
The chemical blending unit is designed to produce batch quantities of various blended polyol and isocyanate products, and to drum polyols and isocyanates. Production of a typical chemical blending product involves the mixing of either a polyol or an isocyanate with small amounts of other raw materials to produce one part of a two-part polyurethane foam producing system. Toluene diisocyanate is the regulated substance in this unit.
diisocyanate that is used at the blending facility is received in bulk via tank truck and is stored in a nitrogen-padded pressure vessel. It is fed via pump to a nitrogen padded mix tank where it is mixed with a polyol and other raw materials to produce one part of a two-part polyurethane foam product as mentioned above.
For the purposes of the Risk Management Plan, the chemical blending unit is considered a separate process from the three polyol production processes. The toluene diisocyanate storage and mix system is independent of the polyol production processes.
Worst-Case and Alternative Release Scenarios:
Two worst case scenarios and two alternative scenarios are included in the Risk Management Plan. The worst case scenarios involve the loss of the contents of an ethylene oxide railcar and the loss of the contents of the toluene diisocyanate tank. The alternative scenarios involve leaks from piping of ethylene oxide and propylene oxide.
The true worst-case release scenari
o for the facility is the loss of the contents of a full ethylene oxide railcar that is temporarily sitting on a storage track. No passive or active mitigation measures were considered, and the ethylene oxide was assumed to be released all at once, form a pool and then boil off. Based on the procedure in the Offsite Consequence Analysis Guidance document, the release would have offsite impact.
A worst-case release scenario involving the loss of the entire contents of the toluene diisocyanate storage tank is also included in the Risk Management Plan because the process using the toluene diisocyanate is covered by Program 1 of the Risk Management Program rule. The tank is located inside a building which is considered a passive mitigation measure because it reduces the release rate of the material to the atmosphere. Based on the procedure in the Offsite Consequence Analysis Guidance document, the release would not have offsite impact.
The alternative release scenarios involve leaks
of ethylene oxide and propylene oxide from feed piping just before it connects to a reactor. These were chosen because minor leaks from small relief valves have occurred at this point in the polyol production processes. In evaluating the releases active mitigation involving the use of level, temperature and pressure monitors on the reactors was considered. The leak would be detected by operations personnel monitoring the reaction process, and they could then shut down the feed to the reactor. Based on the procedure in the Offsite Consequence Analysis Guidance document the releases could impact neighboring chemical plants.
General Accidental Release Prevention Program and Chemical-Specific Prevention Steps:
Our three polyol production processes, P-1/P-2, P-3 and P-4, use ethylene oxide and propylene oxide as major raw materials. These materials are covered by OSHAs Process Safety Management regulations, as well as the Risk Management Program rule, and as such their use has bee
n subject to significant safe management review for some time. Prevention measures in place include extensive process controls (e.g., safety interlocks, pressure monitoring systems, etc.), mitigation systems (i.e. dry and wet sprinklers/deluge systems) and detection systems (i.e., process area hydrocarbon detection systems). We have procedures such as our Preventive Maintenance Program, Lockout/Tagout Procedure, Incident Investigation Procedure and Process Change Authorization Procedure in place to minimize the possibility of an incident. We also have an extensive Chemical Operator Training program in place to ensure that operations personnel know how to operate the processes in a safe manner, and we have performed Process Hazard Analyses to evaluate our systems.
Our chemical blending process which uses toluene diisocyanate as a primary raw material is not covered by OSHAs Process Safety Management regulations and is not subject to the Risk Management Program prevention requirement
s. However, the operation does have standard operating procedures designed to minimize the potential for releases and is covered by the Lockout/Tagout and Incident Investigation procedures at the facility.
Five-Year Accident History:
There has only been one reportable incident during the last five years. The incident involved the failure of a cathodic-protection gasket and subsequent leak from the pipeline supplying propylene oxide to the facility in September 1995. There was no offsite impact, but there was significant equipment damage onsite. A number of changes including installation of new controls and hydrocarbon detectors were made to prevent a recurrence.
Emergency Response Program:
Our Emergency Response Program consists of the following elements: emergency pre-planning including coordination with a local emergency response organization; an incident command system and incident response team; internal plant emergency alarm procedure; call out and internal and externa
l notification procedures; and response procedures for chemical releases and other emergencies. Training is provided annually on the management of emergencies involving hazardous materials and fire response. Plant drills are conducted regularly, and we participate in drills with the local emergency response organization.
Planned Changes to Improve Safety:
No significant changes are planned at this time.