Air Products, Salisbury - Executive Summary |
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Executive Summary Air Products and Chemicals, Inc. Salisbury, Maryland Hydrogen Facility 1. Accidental release prevention and emergency response policies: At this facility, we manufacture gaseous hydrogen. Hydrogen, in the amounts handled by our facility, exceeds the threshold quantity set by EPA. It is our policy to adhere to all applicable Federal and state rules and regulations. Air Products manages the safety of the regulated processes by means of operating procedures, equipment testing and inspections, safety devices (e.g., alarms, shutdowns, instrumentation, relief devices) inherent in the design of this facility and other controls and systems designed to prevent accidental release of hazardous chemicals. Safe work practices and training of our personnel supplement the inherent safe design of the plant. Our emergency response program is based upon OSHAs HAZWOPER regulation. The emergency response plan includes procedures for the notification of the local fire authori ty and Hazardous Materials unit so that appropriate measures can be taken by local responders to control accidental releases. This document has been prepared in accordance with the EPAs Risk Management Plan regulation (40 CFR, Part 68). The substances and processes considered during the preparation of this RMP and the scenarios described were selected based on criteria established in the regulation. 2. The stationary source and regulated substances handled: The primary purpose of this facility is to manufacture hydrogen gas. Hydrogen is used by our customer in their manufacturing process. Natural gas (predominantly methane) is received by our plant via pipeline and used as our feedstock. The feed stock is compressed, mixed with steam, and sent to the reformer furnace. In the reformer furnace, the feedstock and steam are heated in the presence of a catalyst to approximately 1550 degrees F, where a chemical reaction takes place that converts the mixture into hydrogen, carbon mo noxide, and carbon dioxide. The carbon monoxide and carbon dioxide are then separated from the hydrogen in adsorbers and returned to the reformer (with some residual hydrogen and methane) to be burned as fuel. The pure hydrogen is then delivered to the customer via pipeline and is also used to keep the onsite gaseous storage vessels pressurized. Backup is provided by a liquid hydrogen storage system. The gaseous hydrogen storage system consists of three vessels. Pure hydrogen gas from the manufacturing plant is stored in the vessels to provide the customers needs during brief periods when usage exceeds the plants production capacity, or during short plant outages. The liquid hydrogen storage system consists of one 25,000 gallon tank and a bank of ambient air vaporizers. The liquid hydrogen is delivered by tank truck. Vaporized liquid hydrogen is used to provide the customers needs when the hydrogen plant is not operating for an extended period of time. The regulated proc ess at this facility is the hydrogen production (reformer) plant and the backup systems. Hydrogen is the only regulated substance handled at this facility in an amount exceeding the threshold quantity. The combined maximum amount of hydrogen and hydrogen-containing flammable mixtures at this facility is 17,000 pounds. 3. The worst-case release scenario(s) and the alternative release scenario(s), including administrative controls and mitigation measures to limit the distance for each reported scenario: The "worst-case scenario" (WCS), as defined by the EPA, is a catastrophic failure of the liquid hydrogen storage tank, releasing all 25,000 gallons (14,770 pounds) of liquid hydrogen which is assumed to form a vapor cloud and ignite resulting in a vapor cloud explosion (VCE). The maximum distance to the EPA-defined end point ( 1 psi overpressure ) for this WCS will reach receptors off site. Although we have active controls directed at preventing such releases, no credit for act ive or passive mitigation measures were taken into account in evaluating this WCS. The "alternative case scenario" (ACS) is a break in the 1 inch liquid line to the vaporizers. The flow area of the break results in a flow rate equal to 20% of the full-bore (guillotine break) flow rate. Liquid hydrogen is assumed to flow from the tank continuously, forming a steady-state vapor cloud. All of the liquid hydrogen released (9845 pounds) is assumed to vaporize quickly without producing any appreciable liquid pool. The vapor cloud formed is presumed to find a source of ignition resulting in a flash fire . The release is expected to continue until the tank (holding, on average, about 16,667 gallons of liquid hydrogen) is drained. The maximum distance to the EPA-defined end point (the lower flammability limit of 4% hydrogen in air) for this event reaches receptors off site. No preventive controls, or active or passive mitigation measures were accounted for in evaluating this ACS. 4. The general accidental release prevention program and specific prevention steps: The facility developed prevention program elements based on the Federal EPAs Accidental Release Prevention Plan and OSHAs Process Safety Management (PSM) regulation. This facility was designed and constructed to comply with applicable state and industry codes. 5. Five-year accident history: The liquid hydrogen tank was installed in November of 1991. The hydrogen plant and gas storage system were brought on line in August of 1998. In the last five years there have been no accidents involving, or accidental releases of, flammable gas that resulted in any deaths, injuries, or significant property damage on site; or known off-site deaths, injuries, evacuations, sheltering in place, property damage, or environmental damage. 6. The emergency response program: The facilitys emergency response program is based upon OSHAs HAZWOPER standard. At this site, employees are trained to recognize emergencie s and initiate emergency response from Perdue Farms and outside agencies. They have been trained to OSHAs First Responder Awareness Level. The employees receive annual refresher training in their role in the emergency plan. Emergency response activities have also been coordinated with the Parsonburg Fire Department for fires related to the flammable process. Periodic drills are conducted to review the effectiveness of our emergency procedures. 7. Planned changes to improve safety: The facility resolves recommendations from PHAs and Incident Investigations, some of which may result in modifications to the plant design and operating procedures. |