Reddy-East Point - Executive Summary
The Reddy East Point facility located in East Point, Georgia manufactures ice for wholesale/retail distribution. The facility utilizes approximately 30,000 pounds of anhydrous ammonia as a refrigerant for ice manufacturing and storage. |
The facility has two refrigeration systems with standard refrigeration design using anhydrous ammonia as its refrigerant. The systems are referred to as the "Turbo" and "Tube" systems. Each of the systems has numerous protective controls (motor overload, high discharge temperature, high discharge pressure, low suction pressure, and low oil pressure) that will shut down the compressor if operating limits are violated.
The Turbo system consists of six 100-ton TIGAR Turbo icemakers and handles all the plant refrigeration requirements. The system consists of four compressors; two 700 HP driven Frick screw compressors, one 400 HP driven Dunham Bush screw compressor, and one 300 HP driven Frick screw compressor. An RWB II Plus Panel provides control for
each of the compressors, inclusive of a standard 3-phase starter system with safety shutdown features utilizing normal refrigeration pressure controls and cutout protection. The four Turbo system compressors are economized and maintain a suction pressure of approximately 12 psi on the ice maker and refrigeration evaporators.
The system compresses the anhydrous ammonia gas to a pressure of approximately 160 psi and discharges the gas into five water evaporative condensers located on the roof of the engine room which houses the compressors. As the gas is liquified in the condensers, it flows into a pilot vessel, holding approximately 1000 pounds at 160 psi, where float switches control solenoid valves which allow the liquid to flow into a medium pressure receiver. This receiver maintains a pressure of near 47 psi and contains a level of approximately 9 feet (10,000 pounds) of refrigerated ammonia at 32 F.
The medium pressure vessel serves as the anhydrous ammonia supply storage.
This vessel, equipped with high-level shutdown protection, feeds the accumulator vessel located at the end of the suction line and provides protection to the compressor from liquid ammonia. Float controls maintain approximately 9 feet (10,000 pounds) of refrigerated ammonia at 0 F and 15 psi in this accumulator. This refrigerated anhydrous ammonia supply is pumped to the ice maker and refrigeration evaporators. Sensors monitor output pressure from the ammonia pumps and regulate frequency inverters that control the pump motor speed. This process continues as long as the system is operating.
The Tube system consists of four 40-ton Cassco tube ice makers equipped with two 200 HP Frick screw compressors and two Micom reciprocating compressors with 75 and 100 HP, respectively. The two Frick compressors are operated by an RWB II Plus control panel and the two Micom compressors have a standard 3-phase starter with standard safety shutdown features utilizing normal refrigeration pressure
controls with cutout protection.
The Tube system compressors maintain a suction pressure of approximately 170 psi and discharge the gas into two water evaporative condensers located on the roof of the engine room, housing the compressors. As the gas is liquified in the condensers it flows back to a high-pressure receiver (approximately 5,000 pounds at 170 psi) located in the engine room. As required, liquid anhydrous ammonia from the receiver is routed by pressure through the coils in the ice makers which pre-chills the liquid ammonia and supplies an accumulator (approximately 3000 pounds at 25 psi) vessel located above the receiver. The refrigerated liquid ammonia is then pumped to the evaporator area of the ice makers. This process continues as long as the system is operating.
An outside supplier delivers anhydrous ammonia to the facility to replenish the ammonia in the system, as required.
Anhydrous ammonia, when properly used, has proven to be a safe and reliable refrigeran
t. The sharp odor of ammonia provides its own warning agent. Practically all accidents involving anhydrous ammonia are the result of a lack of knowledge, misunderstanding, carelessness or poorly maintained or unsuitable equipment.
The Reddy East Point facility is committed to operating a safe and compliant facility for the protection of its employees, the general public, and the environment. The facility has multiple safeguards pertinent to the anhydrous ammonia process. These include an ammonia detection and alarm system, exhaust purge fans, controls which shut down the compressors if operating limits are violated, and the capability of shutting the entire system down if required. Administrative controls are in place which limit the utilization of vessels at approximately 50% of their intended capacities.
The company has developed an emergency response and action plan which includes notification of emergency authorities/agencies and the public, to evacuation and first responder
The Reddy East Point facility has developed a management system to oversee the implementation of the risk management program elements. A single person has been identified that has overall responsibility for developing, implementing and integrating the risk management program requirements.
There may be different levels of responsibility assigned, depending on the size and complexity of the facility. A Risk Management Coordinator may be responsible for developing and implementing the overall risk management program, while other personnel may be responsible for developing and implementing the operating procedures element or developing a particular operating procedure. The management system is, therefore, operating at each of these levels depending on the way these responsibilities are carried out.
The Risk Management Coordinator is responsible for all aspects of the development and update of the overall Risk Management Program. The coordinator will dete
rmine the necessity of establishing additional responsibilities for facility personnel concerning various operations at the facility. As other personnel are identified, they will be documented and lines of authority will be defined within the management system.
By defining the lines of authority and roles and responsibilities of staff that oversee the risk management program elements it will:
Ensure effective communication about process changes;
Clarify the roles and responsibilities related to process safety issues;
Avoid problems or conflicts among the people responsible for implementing elements of the program; and
Ensure that the program elements are integrated into an ongoing approach to identifying hazards and managing risks.
Management commitment to process safety is critical in the facility's risk management program. For process safety to be a constant priority, the facility will remain committed to every element of the risk management program.
To maintain an inte
grated approach to managing risks, each RMP rule element will be implemented on an ongoing, daily basis and become a part of the way the facility operates.
Risk Management Coordinator: Gary Hull
Additional Responsible Personnel: None at this time.
As required by the Risk Management Program regulations, the Reddy East Point facility has conducted offsite consequence analyses relative to the potential accidental release of anhydrous ammonia. The scenarios related to a worst case release scenario and an alternative release scenario. This involved calculating worst case and alternative scenarios utilizing the RMP*Comp modeling program.
The facility considered worst case release scenarios relating to the Turbo system accumulator within the enclosed ammonia system, as it would house the largest mass of a regulated substance at any given time. The release model considered the potential release of 10,781 pounds of liquid ammonia from the vessel, during a
10 minute release. The scenario endpoint was 0.6 mile. This scenario generated a toxic endpoint of 200 ppm, the maximum airborne concentration below which it is believed nearly all individuals can be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individuals ability to take protective action.
Alternative scenarios, or potentially more likely scenario, for the facility system were considered and it was determined that there is a potential release due to the breaking of a 2" line and the subsequent release of 10,100 pounds of ammonia. The predicted distance to the 200 ppm endpoint is 0.3 mile.