Columbia Crest Winery and Vineyards - Executive Summary
The Columbia Crest Winery and Vineyards is a manufacturer of premium wines from the Columbia Valley. The ammonia refrigeration process cools the building and refrigerates the wine in tanks. The system is a closed loop system that utilizes a single component fluid (anhydrous ammonia) as both a refrigerant and a heat transfer medium. The gaseous ammonia is separated from liquid ammonia at two accumulators, compressed, cooled to condense the gas to liquid, stored in a receiver-dryer pressure vessel, and pumped to evaporators in various areas of the plant. Where the cooling is needed the liquid is evaporated, reducing its temperature. The ammonia fluid then passes through a heat exchanger that allows the ammonia to absorb heat from the medium being cooled (for example air, water or wine). At this point the ammonia is mostly gas and is returned to accumulators prior to recompression and recirculation in the system. This system is subject to the OSHA PSM standard and EPCRA emergency |
planning requirements, as well as the Risk Management Program requirements.
The primary ammonia storage vessel is the high pressure receiver-dryer, which may contain up to 14,500 pounds of ammonia; there are no plans to increase this amount. The worst-case release scenario considered in the Off-Site Consequences Analysis was the release of the entire 14,500 pounds from the receiver-dryer in a period of 10 minutes (an extremely unlikely occurrence, but required under the EPA Risk Management Program rule). According to EPA published guidance information, this release would result in potential off-site toxic endpoint concentrations. An alternative case release scenario of 6,000 pounds released in 60 minutes would not result in toxic endpoint concentrations off-site, but may impact the on-site public wine retail shop, according to the EPA published information.
The prevention program includes preventive maintenance, equipment inspections and tests, employee training, management of cha
nge and pre-startup reviews, and safety in design. The safety systems, devices, and procedures that are incorporated into the design and operation of the refrigeration system are as follows:
- The emergency king valve remote shutoff switch de-energizes the solenoid, closing the king valve on the outlet line of the high pressure receiver-dryer, thus preventing the distribution of ammonia out of the receiver-dryer; compressors and condensers continue to operate, evacuating ammonia from the evaporators and pipelines;
- Automatic compressor shutoffs are activated when any of the following occurs; low suction pressure, high discharge pressure, high discharge temperature, high oil temperature, low oil pressure and motor overload; because of check valves and isolation valves, one or more compressors can be taken out of service without leaks and without disabling the entire system;
- Redundant pressure relief valves on each pressure vessel automatically activate when pressure is higher th
an the design pressure; receiver-dryer and compressors will release at an overpressure of 250 psi, while accumulators, chilled water system and wine cooler will release at 150 psi;
- There are isolation valves that allow for minimizing leaks and minimizing evacuation volumes during repairs on each main supply line, tank pad, solenoid valve, compressor, condenser, pressure vessel, evaporator and wine cooler;
- Each compressor and liquid pump has one-way check valves at the suction and discharge lines to minimize leakage during a failure; in addition, each liquid pump has double mechanical seals to prevent leakage;
- An automatic process control system monitors and controls the flow of ammonia, activating alarms and automatic shutoffs if the process parameters are outside of the pre-set limits;
- Each accumulator has high and low level switches that activate the liquid pumps to maintain the level within the prescribed range; if the level exceeds a high level, an alarm is sounded;
Major components, such as fans, evaporators, pumps, and compressors are individually wired to the control system so that an alarm is activated if any component fails;
- All ammonia piping is located outside of the authorized range of vehicular traffic to minimize the potential of an impact and subsequent release of ammonia; pipes are either overhead and above the authorized height range of vehicles, on the roof, in areas where vehicles are not authorized to travel, or in areas where vehicles are not able to travel;
- All ammonia piping and valving is schedule 80 equipment specifically designed and manufactured for ammonia service; the piping slopes toward the compressor room so that during an equipment failure and/or loss of power, liquid ammonia will flow toward the compressor room instead of toward the failed equipment.
- Ammonia detectors activate a louvered opening and high capacity exhaust fan in the compressor room in the event of a leak to prevent buildup of explosive concent
rations of ammonia in the room.
Employees are trained in the use of personal protective equipment to respond to leaks and equipment failures by evacuating personnel and repairing the equipment as quickly as possible. Automatic monitoring equipment with alarms provide an early warning for maintenance and repairs.
There is a detailed emergency and evacuation assessment procedure in place for accidental ammonia releases and other emergencies, including fires, at the winery. The emergency response to an accidental release that may get off-site will be coordinated through the Paterson Fire Department; the senior fire department officer will assume control of the emergency response and public notification.
There have been no accidental ammonia releases at the winery that caused on-site injuries or off-site evacuations or injuries.