Mixed refrigerant/expander process for the recovery of C3+ hydrocarbons

摘要

The present invention is an energy efficient process for the recovery and purification of C3+ hydrocarbons from a high pressure natural gas or refinery/petrochemical feed gas containing C3+ hydrocarbons and light gases. In the process, the high pressure feed gas is initially cooled by heat exchange with a multi-component refrigerant fluid circulating in a closed-loop cycle thereby condensing a large portion of the C3+ hydrocarbons. The non-condensed, remaining gas is work expanded to an intermediate pressure thus providing refrigeration for condensing the remaining C3+ hydrocarbons. The condensed C3+ hydrocarbon liquid streams are combined and are further purified by distillation in an integrated distillation column. Optically, refrigeration for refluxing the integrated distillation column can be provided by the mixed refrigerant cycle.