LIQUEFYING A STREAM ENRICHED IN METHANE

摘要

Liquefying a stream enriched in methane comprising a) supplying a natural gas stream to scrub column, removing in the scrub column heavier hydrocarbons from the natural gas stream to obtain a gaseous overhead stream withdrawn from the top of the scrub column, partly condensing the gaseous overhead stream and removing from it a condensate stream, which is returned to the upper part of the scrub column as reflux; b) liquefying the stream enriched in methane in a tube arranged in a main heat exchanger by indirect heat exchange with a multicomponent refrigerant evaporating at low refrigerant withdrawn from the shell side of the main heat exchanger and partly condensing it at an elevated refrigerant pressure, and c) compressing the multicomponent refrigerant pressure in a tube arranged in an auxiliary heat exchanger by indirect heat exchange with an auxiliary multicomponent refrigerant evaporating at low auxiliary refrigerant pressure to obtain multicomponent refrigerant for use in step b), wherein partly condensing the gaseous overhead stream is done in a tube arranged in the auxiliary heat exchanger.