Active stress control during rapid shut down

摘要

A closed loop refrigerant expansion system with a tube and shell condenser is provided with a control which, upon shutdown, causes the flow of refrigerant to reverse from the evaporator to the condenser to thereby both reduce the amount of refrigerant vapor passing to the condenser and increase the amount of liquid refrigerant in the condenser to thereby reduce the maximum temperature load in the condenser. Reverse flow can be made to occur either by reversing the direction of the refrigerant pump or opening a bypass valve around the pump.

主权项

1. A method of reducing the maximum temperature load in a tube and shell condenser of a closed loop refrigerant expansion system, comprising the steps of:
providing a pump for pumping liquid refrigerant from the condenser to an evaporator during normal operation; a turbine being provided between said condenser and said evaporator, and driving a generator; sensing when the system is shut down and responsively causing the liquid refrigerant to flow in reverse from the evaporator to the condenser to thereby both reduce the amount of refrigerant vapor passing to the condenser and increase the amount of liquid refrigerant in the condenser; and the step of causing the flow to reverse is accomplished by one of (a) operating said pump in reverse, or (b) opening a bypass valve to allow the refrigerant to flow around said pump.