Process and system for recovering natural gas liquids (NGL) from flare gas using Joule-Thomson (J-T) cooling and membrane separation
AssigneeMembrane Technology and Research, Inc.
InventorsKaaeid A. Lokhandwala, Sachin Joshi
Life of this patent
Estimating the term…
Abstract
A process and system for recovering natural gas liquids (NGL) using a combination of J-T cooling and membrane separation. The process involves compressing, separating, and cooling a flare gas stream comprising at least methane and C3+ hydrocarbons prior to being introduced to a J-T valve. The cooled stream exiting the J-T valve is further separated, producing a NGL product stream and an uncondensed gas stream. The uncondensed gas stream is directed to a membrane separation step, which results in a C3+ hydrocarbon enriched stream and a C3+ hydrocarbon depleted stream. The C3+ hydrocarbon enriched stream may be recycled back to the process to recover more NGL.
Claims26
A system for recovering natural gas liquids from flare gas, comprising:
- (a) a compressor including a gas mixture stream inlet and a compressed gas outlet;
- (b) a first separation unit including a compressed gas inlet, a first hydrocarbon liquid stream outlet, and a first gas stream outlet, wherein the compressed gas inlet is in gas communication with the compressed gas outlet;
- (c) a heat-exchanger including a first gas stream inlet, a cooled gas stream outlet, a second gas stream inlet, and a heated gas stream outlet, wherein the first gas stream inlet is in gas communication with the first gas stream outlet of the first separation unit;
- (d) a Joule-Thomson (J-T) valve including a J-T inlet and a J-T outlet, wherein the J-T inlet is in gas communication with the cooled gas stream outlet of the heat-exchanger;
- (e) a second separation unit including an expanded gas inlet, a second hydrocarbon liquid stream outlet, and a second gas stream outlet, wherein the expanded gas stream inlet is in gas communication with the J-T outlet of the J-T valve, wherein the second gas stream outlet is in gas communication with the second gas stream inlet of the heat-exchanger;
- (f) a third separation unit including a second hydrocarbon liquid stream inlet, a third gas stream outlet, and a third hydrocarbon liquid stream outlet, wherein the second hydrocarbon liquid stream inlet is in fluid communication with the second hydrocarbon liquid outlet of the second separation unit;
- and
- (g) a membrane unit including a feed side and a permeate side, wherein the feed side is in gas communication with the heated gas stream outlet of the heat-exchanger and the third gas stream outlet of the third separation unit, and wherein the feed side is also in gas communication with the gas mixture stream inlet of the compressor.
A system for recovering natural gas liquids from flare gas, comprising:
- (a) a compressor including a gas mixture stream inlet and a compressed gas outlet;
- (b) a first separation unit including a compressed gas inlet, a first hydrocarbon liquid stream outlet, and first gas stream outlet, wherein the compressed gas inlet is in gas communication with the compressed gas outlet;
- (c) a heat-exchanger including a first gas stream inlet, a cooled gas stream outlet, a second gas stream inlet, and a heated gas stream outlet, wherein the first gas stream inlet is in gas communication with the first gas stream outlet of the first separation unit;
- (d) a Joule-Thomson (J-T) valve including a J-T inlet and a J-T outlet, wherein the J-T inlet is in gas communication with the cooled gas stream outlet of the heat-exchanger;
- (e) a second separation unit including an expanded gas inlet, a second hydrocarbon liquid stream outlet, and a second gas stream outlet, wherein the expanded gas stream inlet is in gas communication with the J-T outlet of the J-T valve, wherein the second gas stream outlet is in gas communication with the second gas stream inlet of the heat-exchanger;
- (f) a third separation unit including a second hydrocarbon liquid stream inlet, a third gas stream outlet, and a third hydrocarbon liquid stream outlet, wherein the second hydrocarbon liquid stream inlet is in fluid communication with the second hydrocarbon liquid outlet of the second separation unit;
- and
- (g) a membrane unit including a feed side and a permeate side, wherein the feed side is in gas communication with the heated gas stream outlet of the heat-exchanger and the third gas stream outlet of the third separation unit, and wherein the permeate side is in further gas communication with the gas mixture stream inlet of the compressor.
Dependencies are inferred from the claim text.