Patent ID: 9423175
Filing Date: 2016-08-23
CPC Classification: F25J

Claim Text:
1. A method of flexible ethane recovery in a gas processing plant for processing a feed gas including a first portion of the feed gas and a second portion of the feed gas, wherein the gas processing plant is configurable in either an ethane recovery configuration or an ethane rejection configuration, the method comprising: feeding a first reflux stream, a second reflux stream, and a demethanizer feed to a demethanizer; wherein the second portion of the feed gas forms the demethanizer feed after cooling and expansion, and wherein the first and second reflux streams are fed to the demethanizer at different first and second reflux locations; routing a demethanizer overhead product stream to a residue gas recycle exchanger having a first and second heat transfer pathway through the recycle exchanger, wherein; when the gas processing plant is in the ethane recovery configuration, the demethanizer overhead product stream is used to cool the first portion of the feed gas in the first heat transfer pathway to thereby produce the first reflux stream and to cool a portion of compressed residue gas in the second heat transfer pathway to thereby produce the second reflux stream; and when the gas processing plant is in the ethane rejection configuration, the demethanizer overhead product is used to cool the first portion of the feed gas in each of the first and second heat transfer pathways to thereby produce the first and second reflux streams; and using a demethanizer bottom to cool the second portion of the feed gas and feeding the demethanizer bottom after the cooling step to a deethanizer or deethanizer section of the demethanizer.