# US 8,784,761 B2 · Single absorber vessel to capture CO2 > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,761 B2 - Document ID: US8784761B2 - Status: Granted - Kind: B2 - Application number: 12/622,653 - Filed: 2009-11-20 - Published: 2011-05-26 - Granted: 2014-07-22 - Earliest claimed: 2009-11-20 - Assignees: ALSTOM Technology Ltd - Applicants: Sanjay K. Dube; Rameshawar S. Hiwale; Peter U. Koss; David J. Muraskin - Inventors: Sanjay K. Dube; Rameshawar S. Hiwale; Peter U. Koss; David J. Muraskin - Web page: https://patentgrep.com/patent/US8784761B2 ## CPC - B01D 53/1475: {Removing carbon dioxide} - B01D 53/1406: {Multiple stage absorption} - B01D 53/1425: {Regeneration of liquid absorbents} - B01D 53/62: Carbon oxides - B01D 2252/102: Ammonia - B01D 2257/504: Carbon dioxide - B01D 2258/0291: from waste incineration plants - Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters - 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) - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE - Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG] ## Abstract A system for removing carbon dioxide from a flue gas stream is provided, the system comprising an absorber vessel configured to receive a flue gas stream, the absorber vessel comprising a first absorption stage configured to receive the flue gas stream and contact it with a first ionic solution, a second absorption stage configured to receive flue gas which has passed the first absorption stage and contact it with a second ionic solution, a first sump vessel, and a second sump vessel. Furthermore, a method for removing CO2 from a flue gas stream containing CO2 is provided, the method comprising the steps of a) contacting a flow of a first ionic solution comprising NH3 with a flue gas stream to remove a first portion of CO2 from the flue gas stream, b) collecting the used ionic solution from step a) in a first sump vessel, c) recycling ionic solution from the first sump vessel to step a), d) contacting a flow of a second ionic solution comprising NH3 with the flue gas stream to remove a second portion of CO2 from the flue gas stream, e) collecting the used ionic solution from step d) in a second sump vessel, and f) recycling ionic solution from the second sump vessel to step d). ## Claims ### Claim 1 Method for removing CO2 from a flue gas stream containing CO2, the method comprising the steps of: arranging in a single absorber vessel a) in a cycle, contacting a flow of a first ionic solution comprising NH3 with a flue gas stream to remove a first portion of CO2 from the flue gas stream to produce a used first ionic solution, b) collecting the used first ionic solution in a first sump vessel to obtain the first ionic solution, said first sump vessel defined by a first division of a sump of the single absorber vessel, and c) recycling the first ionic solution from said first sump vessel back to flue gas stream to complete the cycle and remove another first portion of CO2 from the flue gas stream, and d) in a cycle, contacting a flow of a second ionic solution comprising NH3 with the flue gas stream to remove a second portion of CO2 from the flue gas stream to produce a used second ionic solution, e) collecting the used second ionic solution in a second sump vessel to obtain the second ionic solution, said second sump vessel defined by a second division of a sump of the single absorber vessel, and f) recycling the second ionic solution from said second sump vessel back to flue gas stream to complete the cycle and remove another second portion of CO2 from the flue gas stream. ### Claim 2 (depends on 1) The method according to claim 1, wherein the sump of the single absorber vessel is disposed in a lower portion of the single absorber vessel. ### Claim 3 (depends on 1) The method according to claim 1, wherein contacting the flow of the first ionic solution with the flue gas stream is performed under conditions such that solid ammonium bicarbonate is formed. ### Claim 4 (depends on 3) The method according to claim 3, wherein collecting the used second ionic solution in a second sump vessel includes adjusting the composition and properties of the used second ionic solution to obtain the second ionic solution. ### Claim 5 (depends on 1) The method according to claim 1, wherein said first ionic solution has a NH3-to-CO2 mole ratio (R) in the range of 1.2 to 2.0. ### Claim 6 (depends on 1) The method according to claim 1, further comprising the step of adjusting the NH3-to-CO2 mole ratio (R) of the ionic solution in the first sump vessel to be in the range of 1.2 to 2.0. ### Claim 7 (depends on 6) The method according to claim 6, wherein the adjustment of the NH3-to-CO2 mole ratio (R) is achieved by introducing NH3 and/or a medium having a NH3-to-CO2 mole ratio (R) higher than the R of the ionic solution into the first sump vessel. ### Claim 8 (depends on 7) The method according to claim 7, wherein said medium is ionic solution from the second sump vessel. ### Claim 9 (depends on 1) The method according to claim 1, wherein contacting the flow of the second ionic solution with the flue gas stream is performed under conditions such that essentially no solid ammonium bicarbonate is formed. ### Claim 10 (depends on 1) The method according to claim 1, wherein said second ionic solution has a NH3-to-CO2 mole ratio (R) in the range of 2.0 to 4.0. ### Claim 11 (depends on 1) The method according to claim 1, further comprising the step of adjusting the NH3-to-CO2 mole ratio (R) of the ionic solution in the second sump vessel to be in the range of 2.0 to 4.0. ### Claim 12 (depends on 11) The method according to claim 11, wherein the adjustment of the NH3-to-CO2 mole ratio (R) is achieved by introducing NH3 and/or a medium having a NH3-to-CO2 mole ratio (R) higher than the R of the ionic solution in the second sump vessel into the second sump vessel. ### Claim 13 (depends on 1) The method according to claim 1, wherein the temperature of the first ionic solution in step a) is controlled to be in the range of 5 to 20° C. ### Claim 14 (depends on 1) The method according to claim 1, wherein the temperature of the second ionic solution in step d) is controlled to be in the range of 5 to 20° C. ### Claim 15 (depends on 1) The method according to claim 1, further comprising the step of contacting a flow of a third ionic solution comprising NH3 and having a NH3-to-CO2 mole ratio (R) in the range of 1.2 to 2.0 with the flue gas stream to remove a third portion of CO2 from the flue gas stream. ### Claim 16 (depends on 15) The method according to claim 15, wherein said flow of a third ionic solution is delivered from the first sump vessel. ### Claim 17 (depends on 16) The method according to claim 16, wherein said flow of a third ionic solution is delivered via a device configured to reduce the amount of solids in the ionic solution. ### Claim 18 (depends on 15) The method according to claim 15, wherein the temperature of the third ionic solution is controlled to be in the range of 10° C. or lower. ### Claim 19 Method for removing CO2 from a flue gas stream containing CO2, the method comprising the steps of: arranging in a single absorber vessel a) in a cycle, contacting a flow of a first ionic solution comprising NH3 with a flue gas stream to remove a first portion of CO2 from the flue gas stream to produce a used first ionic solution, b) collecting the used first ionic solution and receiving regenerated ionic solution in a first sump vessel to obtain first ionic solution, and c) recycling first ionic solution from said first sump vessel back to flue gas stream to complete the cycle and remove another first portion of CO2 from the flue gas stream, and d) in a cycle, contacting a flow of a second ionic solution comprising NH3 with the flue gas stream to remove a second portion of CO2 from the flue gas stream to produce a used second ionic solution, e) collecting the used second ionic solution and receiving regenerated ionic solution in a second sump vessel to obtain second ionic solution, and f) recycling second ionic solution from said second sump vessel back to flue gas stream to complete the cycle and remove another second portion of CO2 from the flue gas stream. ### Claim 20 (depends on 19) The method according to claim 19, wherein the first sump vessel is defined by a first division of a sump of the single absorber vessel; and the second sump vessel is defined by a second division of a sump of the single absorber vessel. ### Claim 21 (depends on 19) The method according to claim 19, wherein collecting the used first ionic solution in a first sump vessel includes adjusting the composition and properties of the used first ionic solution to obtain the first ionic solution.