Patent ID: 11866667
Assignee: LIQUIDE ADVANCED TECHNOLOGIES U.S. LLC
Field: Chemical engineering (Chemistry)
Classification: CPC C  B  F  Y | IPC B  C  F

Claim 0:
1. A process for dewpointing natural gas that provides for recovery of NGL, comprising the steps of:
feeding a flow of associated gas, that does not meet a predetermined specification(s) for hydrocarbon dewpoint and/or a gross heating value, to a first gas separation membrane-based separation stage comprising one or more gas separation membranes selective for C2+ hydrocarbons over methane to produce a flow of a first permeate enriched in C2+ hydrocarbons and a flow of a first retentate enriched in methane;
chilling the first permeate to provide a flow of chilled first permeate;
separating the flow of chilled first permeate to produce a flow of a first gaseous phase deficient in C3+ hydrocarbons and a flow of a first liquid phase enriched in C3+ hydrocarbons;
recovering the flow of the first liquid phase as NGL;
feeding the flow of a first retentate, that does not meet a predetermined specification for gross heating value, to a second gas separation membrane-based separation comprising one or more gas separation membranes selective for C2+ hydrocarbons over methane to produce a flow of a second permeate enriched in C2+ hydrocarbons and a flow of a second retentate enriched in methane that meets the predetermined specification;
recovering the flow of a second retentate, the recovered second retentate meeting a predetermined specification(s);
compressing the flow of second permeate; and
feeding the flow of compressed second permeate along with the flow of associated gas to the first gas separation membrane-based separation stage,
wherein the flow of second permeate and the flow of natural gas are combined and compressed prior to being fed to the first gas separation membrane-based separation stage, prior to being combined with the flow of second permeate and compressed, the flow of natural gas has a pressure of 1-15 bar,
and wherein the process further comprises the steps of:
feeding the flow of first gaseous phase to a third gas separation membrane-based separation unit comprising one or more gas separation membranes selective for CO2 over methane to produce a flow of a third permeate enriched in CO2 and a third retentate enriched in methane; and
feeding the flow of compressed third retentate along with the flow of second permeate and the flow of natural gas to the first gas separation membrane-based separation stage.