Patent ID: 8209996

Claim:
A plant comprising: a feed gas separator; an absorber having first and second vapor ports fluidly coupled to the feed gas separator to separately receive a first and a second portion of a feed gas vapor, and having first and second liquid ports fluidly coupled to the feed gas separator to separately receive a first and a second portion of a feed gas liquid, and further having first and second overhead ports fluidly coupled to a downstream distillation column to separately receive a first and a second portion of a downstream distillation column overhead; wherein the absorber is further fluidly coupled to the downstream distillation column such that an absorber bottom product is fed to the downstream distillation column; wherein the first portion of the feed gas vapor and the first portion of the distillation column overhead provide reflux to the absorber, and wherein the second portion of the distillation column overhead provides a vapor stream enriched in ethane for ethane re-absorption and stripping at a bottom portion of the absorber; and a control unit configured to adjust a ratio of the first and second portion of the feed gas vapor, the first and second portion of the feed gas liquid, and the first and second portion of the distillation column overhead such that ethane recovery is increased in a bottom product of the distillation column when the ratio of the first to the second portion of the feed gas vapor is increased, when the ratio of the first to the second portion of the feed gas liquid is increased, and when the ratio of the first to the second portion of the distillation column overhead is decreased.