# US 12,179,145 B2 · Cryogenic separation of carbon dioxide, sulfur oxides, and nitrogen oxides from flue gas > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,179,145 B2 - Document ID: US12179145B2 - Status: Granted - Kind: B2 - Application number: 17/558,903 - Filed: 2021-12-22 - Published: 2022-06-30 - Granted: 2024-12-31 - Earliest claimed: 2020-12-30 - Assignees: The Texas A&M University System - Applicants: The Texas A&M University System - Inventors: Mark T. Holtzapple; M. M. Faruque Hasan; Mohammed Sadaf Monjur - Web page: https://patentgrep.com/patent/US12179145B2 ## CPC - B01D 53/002: {by condensation} - B01D 53/75: Multi-step processes - B01D 53/02: by adsorption, e.g. preparative gas chromatography {(solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01)} - B01D 53/1431: {Pretreatment by other processes} - B01D 53/265: {by refrigeration (condensation)} - B01D 2252/205: Other organic compounds not covered by B01D2252/00 - B01D2252/20494 - B01D 2253/106: Silica or silicates - B01D 2257/302: Sulfur oxides - B01D 2257/404: Nitrogen oxides other than dinitrogen oxide - B01D 2257/504: Carbon dioxide - B01D 2258/0283: Flue gases - 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) ## Abstract A method of removing pollutants from flue gas includes cooling the flue gas to remove condensed water. The flue gas is then compressed and dehydrated. The dehydrated flue gas is chilled to separate pollutants. ## Claims ### Claim 1 A method of using a system to remove pollutants from flue gas, the method comprising: providing the flue gas to the system, the system comprising: a flue gas feed for receiving the flue gas; a first heat exchanger coupled to the flue gas feed, the first heat exchanger thermally removing heat from the flue gas to form a cooled flue gas; a dryer coupled to the cooled flue gas, the dryer forming a dehydrated flue gas; a second heat exchanger coupled to the dehydrated flue gas, the second heat exchanger thermally exposing the dehydrated flue gas to a chilled refrigerant to form a liquid; a pump coupled to the second heat exchanger, the pump increases a pressure of the liquid; and a third heat exchanger that thermally exposes the pressurized liquid to the dehydrated flue gas, the third heat exchanger forming pressurized waste gases; cooling, via the first heat exchanger, the flue gas to remove condensed water; compressing, via the pump, the flue gas; dehydrating, via the dryer, the flue gas; and chilling, via the second heat exchanger, the dehydrated flue gas to condense and separate pollutants. ### Claim 2 (depends on 1) The method of claim 1, comprising pumping the condensed pollutants to a sequestration pressure. ### Claim 3 (depends on 1) The method of claim 1, comprising expanding noncondensible gases. ### Claim 4 (depends on 1) The method of claim 1, wherein the pollutants comprise carbon dioxide and sulfur dioxide. ### Claim 5 (depends on 1) The method of claim 1, wherein the dehydrating comprises use of an adsorbent. ### Claim 6 (depends on 1) The method of claim 1, wherein the dehydrating comprises use of lithium bromide. ### Claim 7 (depends on 5) The method of claim 5, comprising regenerating the adsorbent. ### Claim 8 (depends on 1) The method of claim 1, wherein the chilling comprises utilizing a multi-stage cascade of refrigerants. ### Claim 9 A system for removing pollutants from a flue gas stream, the system comprising: a flue gas feed; a first heat exchanger coupled to the flue gas feed, the first heat exchanger thermally removing heat from the flue gas to form a cooled flue gas; a dryer coupled to the cooled flue gas, the dryer forming a dehydrated flue gas; a second heat exchanger coupled to the dehydrated flue gas, the second heat exchanger thermally exposing the dehydrated flue gas to a chilled refrigerant to form a liquid; a pump coupled to the second heat exchanger, the pump increases a pressure of the liquid; and a third heat exchanger that thermally exposes the pressurized liquid to the dehydrated flue gas, the third heat exchanger forming pressurized waste gases. ### Claim 10 (depends on 9) The system of claim 9, wherein the chilled refrigerant is cycled through a multi-stage refrigeration system. ### Claim 11 (depends on 10) The system of claim 10, wherein the multi-stage refrigeration system comprises a second refrigerant. ### Claim 12 (depends on 9) The system of claim 9, comprising a fourth heat exchanger coupled to the second heat exchanger, the fourth heat exchanger thermally exposing remaining gas to the dehydrated flue gas. ### Claim 13 (depends on 9) The system of claim 9, comprising a fifth heat exchanger coupled to the third heat exchanger, the fifth heat exchanger thermally exposing the waste gases to waste heat from an industrial process. ### Claim 14 (depends on 9) The system of claim 9, wherein the first heat exchanger exchanges heat from the flue gas with cold water. ### Claim 15 (depends on 9) The system of claim 9, comprising a compressor coupled to the flue gas feed upstream of the first heat exchanger. ### Claim 16 (depends on 9) The system of claim 9, wherein the dryer comprises a plurality of vessels containing an adsorbent. ### Claim 17 (depends on 16) The system of claim 16, wherein the adsorbent is silica gel. ### Claim 18 (depends on 16) The system of claim 16, wherein the flue gas is circulated through a first subset of the plurality of vessels while a second subset of the plurality of vessels is regenerated. ### Claim 19 (depends on 16) The system of claim 16, wherein the vessels contain adsorbent beds. ### Claim 20 (depends on 19) The system of claim 19, wherein the adsorbent beds are at least one of conical and cylindrical.