Process and apparatus for the liquefaction of a natural gas stream utilizing a single mixed refrigerant

摘要

In a process for cooling gas fluid feed material from an initial temperature to a second, cryogenic temperature which utilizes a single mixed refrigerant composition whose respective constituents possess a range of successively lower boiling points, wherein said refrigerant composition is passed through a single closed loop refrigeration cycle involving compression, partial condensation in an aftercooler phase separation, heat exchange and expansion, wherein heat exchange occurs in a cold box containing a warm end and a cold end heat exchanger, said exchangers being thermally connected in series relationship, wherein the improvement comprises regulating the flow rate of the vapor-containing refrigerant stream passing from said partial condensation stage by diverting predetermined amounts of liquid refrigerant from the liquid- containing refrigerant stream, also passing from said partial condensation stage, into said vapor-containing stream, said diverting occurring at a point inside the cold box after said vapor- containing stream exits the warm end heat exchanger, but before it enters the cold end heat exchanger. Apparatus to accomplish the process is also disclosed.