Configurations and methods for retrofitting an NGL recovery plant

摘要

Devices and methods for retrofitting a natural gas liquids plant are contemplated to extend recovery of C3+ hydrocarbons from various feed gases to recovery of C2+ and C3+ hydrocarbons. In especially preferred aspects, dedicated C2+ exchangers are integrated to exclusively cool the feed gas to produce a cooled absorber feed and to produce two separate absorber reflux streams. During C2+ recovery, absorber reflux is provided by a portion of the residue gas and a portion of the feed gas, while during C3+ recovery absorber and distillation column reflux are provided by the distillation column overhead product.

主权项

1. A method of retrofitting a natural gas liquids plant for recovery of C2+ hydrocarbons, wherein the natural gas liquids plant has an absorber, a downstream distillation column, and a C3+ recovery exchanger that is configured to cool a feed gas and to cool an overhead product from the distillation column to thereby form a reflux stream for the absorber, and wherein a bottom product of the absorber is fed to the downstream distillation column, comprising:
installing a bypass circuit for the C3+ recovery exchanger that includes first and second dedicated C2+ recovery exchangers; wherein the first C2+ recovery exchanger uses refrigeration content from an absorber overhead product to produce an ultra-lean reflux stream from a portion of compressed residue gas and a reflux stream from a portion of the feed gas; wherein the second C2+ recovery exchanger uses refrigeration content from the absorber bottom product to produce a cooled feed gas from another portion of the feed gas; and installing a bypass that routes the overhead product from the distillation column to the absorber as a stripping vapor.