Process and apparatus for separating hydrocarbon gas into a residue gas fraction and a product fraction

摘要

A process and apparatus for separating a hydrocarbon feed gas into residue gas and a less volatile product fraction utilizing phase separation resulting from cooling. The present invention utilizes a portion of the liquid product fraction as internal refrigerant by expansion-cooling of the fraction which is then recycled after heat exchange to the inlet feed gas. No external refrigeration system is required. Flow of the portion of the liquid product fraction used as internal refrigerant is controlled with a Joule-Thompson valve responsive to the temperature of the residue gas and product fraction as they are separated so as to regulate expansion-cooling to provide a desired composition of the residue gas and the product fraction.