Van Compressor Station - Executive Summary

| Accident History | Chemicals | Emergency Response | Registration | Source | Executive Summary |

                                                       Risk Management Program 
                                                           Executive Summary 
                                              National Fuel Gas Supply Corporation 
                                                        Van Compressor Station 
1)  Accidental Release Prevention and Emergency Response Policies: 
   It is the policy of National Fuel Gas to provide and maintain safe and healthful working 
   conditions and follow sound operating practices that will safeguard our employees, our 
   customers, our community, and environment. We will strive to comply with legislative  
   requirements and eliminate any foreseeable hazards which may result in losses, damage to 
   property, personnel injury and illnesses, and the environment. 
   The Accidental Release Prevention Policy at the facility is embedded in our overall 
   approach to planning, design and constructi 
on intended to minimize hazards; and the 
   training of all personnel in proper operation, maintenance and inspection procedures with 
   emphasis on awareness and practices to minimize hazards and avoid accidents.  The 
   Emergency Response Policy is to identify potential hazards at the facility, and develop and 
   implement a plan to respond to emergency events including, but not limited to fire, 
   accidents or injury.  The Emergency Response Plan includes identification of responders 
   and their duties, and procedures for notification of responders including fire department, 
   evacuation, shutdown, and communications. 
2)  Stationary Source: 
   The purpose of the Van facility is to withdraw field gas from a nearby production well 
   gathering system, remove hydrocarbon liquid and moisture from the gas, raise the pressure 
   of the gas, and deliver it into a natural gas transmission piping system. The operation is 
   carried out by two interrelated, but distinct, majo 
r processes. The process that is covered by 
   this Risk Management Program (RMP) is an extraction process which strips the 
   hydrocarbon liquid (liquid product) from the natural gas, and stores it in a 30,000 gallon 
   tank until it is shipped bi-weekly, via tanker truck. The other major process compresses the 
   natural gas in three stages, pumps it through the extraction process and then into the high 
   pressure transmission system. 
   The extraction system process utilizes in series two counterflow heat exchangers, a chiller, 
   and a three phase separator to reduce the gas temperature and pressure and which induces 
   the liquid product to drop out of the gas stream. The chiller system uses propane refrigerant 
   in a closed loop which includes a compressor, a cooler (condenser), a receiver, the chiller 
   (evaporator), and a suction drum. There is also a 300 gallon propane makeup tank which 
   feeds refrigerant to the closed loop as needed.  After forming in the 
three phase separator 
   the liquid product is passed through the heat exchangers to cool the incoming gas, and then 
   sent to a stabilizer vessel where ethane gas separates (ethane is piped to the natural gas 
   compressor for use as a fuel) and moisture is removed. From the stabilizer the liquid 
   product is piped to the 30,000 gallon storage tank  
   There is also an ethylene glycol dehydration system which removes moisture from the gas 
   stream and the liquid product stream in two loops. In the first loop, glycol is injected into 
   the gas stream at both the first heat exchanger and the chiller, and it is later removed in the 
   three phase separator. In the second loop, glycol passes through the stabilizer to remove 
   water from the liquid product. Both loops send the glycol through a reboiler which heats 
   the glycol to drive off water, and then through a cooler. 
3)  Regulated Substances: 
   The liquid product is a flammable liquid, and consists of an a 
pproximate a mixture of: 
         i)    Ethane: 
         ii)   Propane: 
         iii)  Butane: 
         iv)  Hexane: 
         v)   Pentane: 
   Since the analytical composition of this liquid product varies depending on the gas mixture 
   extracted from the production field, analytical analysis was performed to determine a 
   general composition for this liquid product. This product is stored at approximately 50 to 
   100 pounds per square inch pressure. 
4)  Worst Case Release Scenario: 
   The worst case release scenario, as defined by the EPA, was developed based on a release 
   the largest quantity of liquid that the storage tank could possibly hold, the evaporation of 
   the total quantity, and explosion of the vapor cloud.  The explosion is assumed to reach an 
   end point distance based on a model of an explosion of  TNT in a quantity  that has 10 
   percent of the estimated energy available in the liquid product. 
   This scenario is based on the relea 
se of 30,000 gallons of liquid product, total evaporation, 
   and explodes with an effective radius of 0.4 miles. This scenario is estimated to affect a 
   population of 20 and a Church. 
   The modeling used for end point determination was based on the RMP Off-site 
   Consequence Analysis Guidance (OSA) Document, Published Friday, May 24,1996.  In 
   review of the OSA Document, it was determined to use an atmospheric over-pressure of 
   1.0 pounds per square inch as the end-point for the release.  This end-point was chosen as 
   the threshold because of the potential for serious injury to people as a result of property 
   damage caused by the explosion, glass from shattered windows or falling debris. 
5)  Alternative Release Scenario: 
   This alternate scenario is a release of a quantity of the regulated substance from a vessel or 
   process line failure which is more likely to occur than the worst-case scenario. This release 
   is assumed to result in a vapor clou 
d containing the total quantity of the substance between 
   the Upper and Lower flammability limits which explodes and impacts offsite receptors. 
   The alternative scenario was based on the release of the actual maximum contents of the 
   liquid product storage tank, 18,000 gallons or approximately 81,200 pounds of liquid 
   product, total evaporation, and explosion of the vapor cloud with an effective radius of  
   0.30 miles.  This scenario is estimated to affect a population of 20 and a Church. 
   The actual maximum tank content limit of 18,000 gallons is based on facility practice of 
   keeping the tank at 60 percent or less of full.   
   The modeling used for end point determination was based on the RMP OSA Document.  
   From the OSA Document, it was determined to use an atmospheric over-pressure of 1.0 
   pounds per square inch as the end-point for the release. This end-point was chosen as the 
   threshold because of the potential for serious injury to  
people as a result of property 
   damage caused by the explosion, glass from shattered windows or falling debris. 
6)  General and Chemical-Specific Accidental Release Prevention Program: 
   All personnel are trained in proper operation procedures of all equipment.  Training and 
   testing are conducted on-the-job. Any individual who works in this process must have 
   extensive mechanical abilities, and is thoroughly tested and evaluated in the processing 
   operations as part of the accident release prevention program  
   Valves and other equipment are maintained, tested and replaced in-kind if necessary.   
   Maintenance is performed on all compressors and systems based on written manufacturers' 
   or facility procedures.  The operational systems have general monitoring, maintenance and 
   inspection performed to ensure optimum performance. 
   The system operating parameters and equipment are monitored on a daily basis.  Detailed 
   audio and visual insp 
ections for leaks or signs of failure are conducted monthly.  At least 
   once per year the system is inspected with portable gas detection instruments for leaks 
   from valves, flanges, pressure relief devices, and process equipment. 
   In any instance where liquid product backs up out-of the system it automatically shuts 
   down the compressors, activates the alarm system, and notifies site personnel by the 
   automatic dialing system.. All critical monitoring and valve components have backups.  
   The primary monitoring system includes level, pressure and temperature sensors and 
   switches.  If these fail the system is protected by  numerous pressure relief valves.  In most 
   cases there are redundant relief valves, e.g. there are four redundant relief valve on the 
   30,000 gallon storage tank. 
   The liquid product storage tank which has a maximum capacity of 30,000 gallons is never 
   filled to full capacity. The standard operational procedure for is to mai 
ntain the liquid 
   product storage tank at less than sixty percent of its total  capacity, approximately 18,000 
   gallons.  The storage tank is inspected daily to determine the amount of material present.  
   To maintain this sixty  percent total volume two truckloads per week of the liquid product 
   are shipped when the facility is in full operation. Each shipment consists of approximately 
   8,500 gallons of liquid product per trip from the facility. The transport company, Crossett 
   Trucking, follows specific written operational procedures for transferring liquid product 
   from the storage tank to the tanker truck.  There are spring loaded shut-off valves in the 
   transfer piping to prevent potential releases related to transfer accidents. 
   There is also minimal motor vehicle exposure to the liquid product storage tank,.  It is 
   surrounded by concrete Jersey barriers and access to the facility is normally through locked 
   gates.  This traffic pattern and s 
low speed  reduce the potential exposure from vehicular 
   traffic. All personnel entering the facility first must check in with the site operations 
   personnel to unlock the access gates. 
7)  Five Year Accident History: 
   To date this facility has no release of liquid product or  other related incidents which 
   caused off-site injuries, public evacuations, or any instances where personnel, the public, or 
   the environment have been placed in danger from this operation. 
8)  Emergency Response Program: 
   As part of the Emergency Response Program the Emergency Response Plan for the facility 
   documents and outlines personnel responsibilities and procedures. This Emergency 
   Response Plan is intended to establish a controlled and orderly means of response and 
   control of emergencies in order to avoid unnecessary panic, injury, or death.  During 
   emergencies, existing hazards can change quickly, therefore the Emergency Response 
   Program is intended as a  
guideline for emergency response. 
   The Emergency Response Plan includes notifying and coordinating with local emergency 
   responders, shutting down the compression systems, maintaining communications and 
   evacuating the site. 
   The  site contacts are: 
         Mr. David Gavin                   Office:   814-589-7061      Plant:       814-677-8618  
                                                       Home:    814-827-6734      Mobile:   814-671-7515 
         Mr. Stanley Thompson         Office:    814-589-7161      Home: 814-827-1978  
                                                       Mobile:   814-671-7618 
     National Fuel Gas Supply Corporation           Office: 800-833-1843 
   This operation runs 24 hours a day unless there is equipment repair or shut-down within 
   the facility.  There are operators present every day. Personnel spend several hours a day 
   checking over system conditions and operation.  If there is an emerg 
ency, with or without 
   personnel present the system automatically shuts down, alarms are sounded, and the 
   automatic dial in system immediately contacts and summons personnel to the facility. 
9)  Planned Changes to Improve safety: 
   At the present time all operations are being reviewed and up-dated, and no changes to the 
   operation or equipment at this facility are planned.
Click to return to beginning