# US 2012/0073441 A1 · Configurations And Methods For High Pressure Acid Gas Removal > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0073441 A1 - Document ID: US20120073441A1 - Status: Published application - Kind: A1 - Application number: 13/257,885 - Filed: 2010-03-24 - Published: 2012-03-29 - Earliest claimed: 2009-03-25 - Assignees: Fluor Technologies Corporation - Inventors: John Mak - Web page: https://patentgrep.com/patent/US20120073441A1 ## CPC - B01D 53/1462: {Removing mixtures of hydrogen sulfide and carbon dioxide} - B01D 53/1425: {Regeneration of liquid absorbents} - B01D 53/62: Carbon oxides - B01D 53/78: with gas-liquid contact - C10L 3/102: {of acid contaminants} - B01D 2256/24: Hydrocarbons - B01D 2257/504: Carbon dioxide - Y02C 20/40: of CO2 - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS - Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG] ## Abstract Physical solvent is regenerated using flashing and stripping processes to produce an ultra-lean solvent. In especially preferred aspects, flashed C1-C3 hydrocarbons are recycled to the absorber, while C4+ hydrocarbons are recovered from the CO2 that is removed from the solvent. It is further preferred that depressurization of the rich solvent provides most of the refrigeration duty. ## Claims ### Claim 1 A method of acid gas removal from a feed gas, comprising: contacting the feed gas in an absorber with an ultra-lean physical solvent to form a rich solvent and a treated feed gas; sequentially depressurizing the rich solvent to remove C1-C3 hydrocarbons from the rich solvent to form a depressurized solvent, and recycling the C1-C3 hydrocarbons to the absorber; flashing and stripping the depressurized solvent to produce an ultra-lean solvent and a flashed gas that predominantly comprises CO2 and C4+ components; wherein the step of stripping is performed with a portion of the treated feed gas to form stripped vapors, and wherein the stripped vapors are recycled to the absorber; and separating the flashed gas in a separator to produce a CO2 stream having less than 5% C4+ components and a C4+ product. ### Claim 2 (depends on 1) The method of claim 1 wherein refrigeration content of the depressurized solvent is employed for cooling of at least one of the ultra-lean solvent and the feed gas. ### Claim 3 (depends on 1) The method of claim 1 wherein the depressurized solvent is heated to a temperature of at least 50° F. using heat content of the feed gas. ### Claim 4 (depends on 1) The method of claim 1 wherein the portion of the treated feed gas is heated and then expanded to stripper pressure in a turbo expander to thereby generate power. ### Claim 5 (depends on 1) The method of claim 1 wherein the feed gas entering the absorber has a pressure of at least 1000 psia, comprises at least 10 mol % CO2, and is cooled prior to entering the absorber to a temperature that is effective to condense heavy hydrocarbons. ### Claim 6 (depends on 1) The method of claim 1 wherein the step of sequentially depressurizing the rich solvent comprises depressurization using a hydraulic turbine. ### Claim 7 (depends on 1) The method of claim 1 wherein the step of flashing is performed using a first flashing step to about atmospheric pressure and a second step to below atmospheric pressure. ### Claim 8 (depends on 1) The method of claim 1 wherein the flashed gas is dehydrated in a dehydration unit prior to the step of separating the flashed gas in the separator. ### Claim 9 (depends on 1) The method of claim 1 wherein the CO2 stream from the separator is partially condensed to produce a reflux stream and a CO2 vapor. ### Claim 10 A method of regenerating a physical solvent, comprising: providing a rich physical solvent at a pressure of at least 1000 psig, wherein the rich solvent comprises C1-C3 hydrocarbons, C4+ components, and CO2; sequentially depressurizing the rich solvent to a pressure effective to the remove C1-C3 hydrocarbons from the rich solvent while maintaining substantially all of the CO2 to thereby form a depressurized solvent, and recycling the C1-C3 hydrocarbons to an absorber; flashing the depressurized solvent to a pressure sufficient to release substantially all of the CO2 and C4+ components to thereby form a flashed solvent; separating the C4+ components from the CO2 to thereby produce a CO2 stream having less than 5% C4+ components and a C4+ product; and stripping the flashed solvent with a portion of a treated feed gas to so form an ultra-lean solvent and stripped vapors, and recycling the stripped vapors to the absorber. ### Claim 11 (depends on 10) The method of claim 10 wherein the step of sequentially depressurizing is performed using a hydraulic turbine, and wherein the depressurized rich solvent is used to cool at least one of a feed gas and the ultra-lean solvent. ### Claim 12 (depends on 10) The method of claim 10 wherein the depressurized solvent is heated to a temperature of at least 50° F. using heat content of a feed gas to an absorber. ### Claim 13 (depends on 10) The method of claim 10 wherein the step of flashing is performed using a first flashing step to about atmospheric pressure and a second step to below atmospheric pressure. ### Claim 14 (depends on 10) The method of claim 10 wherein the step of stripping the flashed solvent is performed with a treated feed gas. ### Claim 15 (depends on 14) The method of claim 14 further comprising a step of heating the portion of the treated feed gas and expanding the heated portion of the treated feed gas in a turbo expander to thereby generate power. ### Claim 16 (depends on 10) The method of claim 10 further comprising a step of dehydrating the flashed gas in a dehydration unit prior to the step of separating the C4+ components from the CO2. ### Claim 17 A gas treatment plant comprising: an absorber configured to absorb C1-C3 hydrocarbons, C4+ components, and CO2 from a feed gas using an ultra-lean solvent at a pressure of at least 1000 psig to thereby allow formation of a treated feed gas and a rich solvent; a plurality of flash vessels configured to receive and sequentially flash the rich solvent to produce a depressurized solvent and C1-C3 hydrocarbons; a low-pressure flash stage fluidly coupled to the plurality of flash vessels and configured to flash the depressurized solvent to thereby produce a flashed gas comprising CO2 and C4+ components and a flashed solvent; a stripping column that is fluidly coupled to the low-pressure flash stage and configured to allow stripping of the flashed solvent with a portion of the treated feed gas to so produce the ultra-lean solvent and stripped vapors; a fractionator that is fluidly coupled to the low-pressure flash stage and configured to separate C4+ components from the CO2 to thereby produce a CO2 stream having less than 5% C4+ components and a C4+ product; a first recycle conduit fluidly coupled to the plurality of flash vessels and the absorber for recycling the C1-C3 hydrocarbons to the absorber; and a second recycle conduit fluidly coupled to the stripping column and the absorber for recycling the stripped vapors to the absorber. ### Claim 18 (depends on 17) The gas treatment plant of claim 17 further comprising a heat exchanger configured to allow heating the depressurized solvent using heat from the feed gas. ### Claim 19 (depends on 17) The gas treatment plant of claim 17 wherein the low-pressure flash stage is configured to allow flashing of the depressurized solvent to sub-atmospheric pressure. ### Claim 20 (depends on 17) The gas treatment plant of claim 17 further comprising a separator fluidly coupled to the absorber and configured to allow separation of condensed heavy hydrocarbons from the feed gas.