# US 11,298,654 B2 · Nitrogen oxide absorption slurry and a preparation and use method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,298,654 B2 - Document ID: US11298654B2 - Status: Granted - Kind: B2 - Application number: 17/270,401 - Filed: 2019-10-31 - Published: 2021-08-12 - Granted: 2022-04-12 - Earliest claimed: 2018-11-13 - Assignees: Liwei Huang - Applicants: Liwei Huang - Inventors: Liwei Huang - Web page: https://patentgrep.com/patent/US11298654B2 ## CPC - B01D 53/80: Semi-solid phase processes, i.e. by using slurries - B01D 53/56: Nitrogen oxides (B01D53/60 takes precedence) - B01D 53/96: Regeneration, reactivation or recycling of reactants - B01D 2251/502: Hydrochloric acid - B01D 2251/60: Inorganic bases or salts - B01D 2258/06: Polluted air - Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters - 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 ## Abstract A nitrogen oxide absorption slurry and its preparation and use method for the removal of nitric oxide in gas streams, belonging to the technical field of air pollution control and related environmental protection, is characterized in that the absorption slurry contains one or more compounds of anhydrous ferric chloride, ferric chloride monohydrate, ferric chloride dihydrate and the complex of ferric chloride and chloride ions. The absorption slurry reacts with the nitric oxide in gas stream at a certain temperature, so that the nitric oxide in the gas stream is absorbed by the slurry, thereby achieving the purpose of gas purification. And the absorbent can be recycled after regeneration. ## Claims ### Claim 1 A nitrogen oxide absorption slurry for removing nitric oxide gas from gas streams, wherein said absorption slurry contains any one or two and more compounds of anhydrous ferric chloride, ferric chloride monohydrate, ferric chloride dihydrate, and a complex of ferric chloride and hydrochloric acid, and the mass ratio of water to ferric chloride in the absorption slurry is from 0.005 to 0.55. ### Claim 2 (depends on 1) The preparation method of the absorption slurry according to claim 1, wherein the absorption slurry is prepared by mixing anhydrous ferric chloride and water, or anhydrous ferric chloride and hydrochloric acid, or anhydrous ferric chloride and ferric chloride monohydrate, or anhydrous ferric chloride and ferric chloride dihydrate, or anhydrous ferric chloride and ferric chloride hexahydrate, or anhydrous ferric chloride and ferric chloride monohydrate and hydrochloric acid, or anhydrous ferric chloride and ferric chloride dihydrate and hydrochloric acid, or anhydrous ferric chloride and ferric chloride hexahydrate and hydrochloric acid, respectively, according to said mass ratio under a certain temperature and atmosphere. ### Claim 3 (depends on 2) The preparation method of the absorption slurry according to claim 2, wherein said temperature for preparing the absorbent slurry is 35° C. and above, and said atmosphere is in the presence of air, nitrogen gas or hydrogen chloride gas. ### Claim 4 (depends on 1) The preparation method of the absorption slurry according to claim 1, wherein the absorption slurry is prepared by the dehydration of the ferric chloride solution, or by the dehydration of the mixture of ferric chloride and hydrochloric acid, under a certain temperature and atmosphere. ### Claim 5 (depends on 4) The preparation method of the absorption slurry according to claim 4, wherein said temperature for preparing the absorbent slurry is 65° C. and above, and said atmosphere is in the presence of air, nitrogen gas or hydrogen chloride gas. ### Claim 6 (depends on 2) The preparation method of the absorption slurry according to claim 2, wherein said water can be replaced by a salt solution or a mixture of salt and hydrochloric acid solution, and said salt can be a chloride or sulfate of alkali metal, alkaline earth metal or transition metal, which includes sodium chloride, potassium chloride, lithium chloride, calcium chloride, magnesium chloride, zinc chloride, manganese chloride, cobalt chloride, copper chloride, nickel chloride, aluminum chloride, and the corresponding sulfates. ### Claim 7 (depends on 1) The use method of the absorption slurry according to claim 1, wherein the absorption slurry is introduced into a nitrogen oxide absorption reactor and nitric oxide in gas stream is absorbed by chemical reaction with ferric chloride in the absorbent at a certain temperature. ### Claim 8 (depends on 7) The use method of the absorption slurry according to claim 7, wherein the nitrogen oxide absorption reactor can be a rotating, spraying, bubbling or moving bed type gas-liquid contact reactors, and the flow pattern in the reactor can be used arranged in co-current flow, counter flow and cross flow. ### Claim 9 (depends on 7) The use method of the absorption slurry according to claim 7, wherein the reaction temperature of the absorbent prepared by water and ferric chloride is from 35 to 110° C., and is from 35° C. to 130° C. prepared by hydrochloric acid and/or salt solution instead of water. ### Claim 10 (depends on 1) The regeneration method of the absorption slurry according to claim 1, wherein the regeneration of the absorbent can be implemented by heating or humidifying, or dissolving in water or hydrochloric acid solution to release the absorbed nitric oxide gas from the absorbent, and then followed by dehydration and chlorination process, where the desorption of nitric oxide gas from the absorbent, dehydration and chlorination can be performed simultaneously, and the temperature of said heating is 65° C. and above. ### Claim 11 (depends on 10) The regeneration method of the absorption slurry according to claim 10, wherein the dehydration and chlorination are carried out in the presence of hydrogen chloride gas. ### Claim 12 (depends on 10) The regeneration method of the absorption slurry according to claim 10, wherein the dehydration and chlorination can be carried out by adding sulfoxide chloride solution.