Cryogenic vapour recovery process and system

摘要

A gas stream containing condensable vapours flows through whichever of condenser 16 and 22 is on line. The condensable vapours are condensed therein. A resultant cold, vapour-free, gas stream flows through an economising heat exchanger 18 and is warmed by its passage therethrough. Condensation of the vapour and warming of the cold gas stream is effected by a recirculating refrigerant stream. The refrigerant stream flows through the on-line condenser and is thereby heated. One part of the heated refrigerant stream flows through valve 50 and is employed to warm the cold gas stream in the heat exchanger 18 and is thereby recooled. Liquid cryogen is introduced into the recooled refrigerant stream by means of an ejector 58 which communicates with the on-line condenser to complete the circuit. A second part of the heated refrigerant stream may be vented through valve 52. A third part of the heated refrigerant stream may be employed to defrost the off-line condenser and downstream thereof be introduced into the recooled refrigerant stream.