METHOD FOR LOW-COMPRESSION SELECTIVE EXTRACTION OF CARBON DIOXIDE FROM STREAM OF EXHAUST GASES AND INSTALLATION FOR ITS EXTRACTION Russian patent published in 2025 - IPC B01D53/14 B01D53/62 B01D53/78 

FIELD: heat power engineering.

SUBSTANCE: invention relates to heat engineering, in particular to cleaning of flue gases of heat engineering plants from carbon dioxide. Invention relates to a method of producing carbon dioxide by extracting it from a stream of exhaust gases, in which a gas stream containing carbon dioxide is cooled and supplied cleaned from minor gas impurities into an absorption column, into which an aqueous solution of potash is supplied as an absorbent, a gas stream is reacted with an aqueous solution of potash to form a solution of potassium bicarbonate ion, then the latter is fed into a stripper, in which it is heated to form a stream of potash solution and a stream of gaseous carbon dioxide, then carbon dioxide is supplied to the consumer, and the potash solution is fed into a heat exchanger and then returned to an absorption column for absorption of carbon dioxide. Before feeding into the absorption column, the stream of exhaust gases is cooled to temperature of 20 to 50 °C and for subsequent individual release of carbon dioxide gas is cleaned from minor acid gases by feeding into unit of preliminary cleaning of exhaust gases from minor acid gases, containing as a chemisorbent an alkaline solution with acidity in range of 9 to 12 pH, formed by dissolving sodium or potassium hydroxide in water together with a tetra-substituted sodium ethylene diamine tetraacetate (EDTA) complexon, then, gas flow coming out of said unit is fed into absorption column with counterflow feed of aqueous potash solution with potash concentration of 20 to 27 wt.%. Aqueous solution of potash is supplied under excess pressure from 1 to 4 atm and at temperature from 20 to 50 °C, obtained in the absorption column potassium bicarbonate ion solution is fed through a heat exchanger into a packed stripper, where from the potassium bicarbonate ion solution heated to temperature from 80 to 90 °C carbon dioxide is extracted, which is fed into the gravity separator-cooler, in which the main part of the moisture is separated, and then fed into a unit of deep adsorption treatment, from where with temperature of 20 to 30 °C carbon dioxide is either fed into a unit for producing commercial carbon dioxide, where it is either compressed and pumped into cylinders, or depending on the need for one or another commercial product due to cryo-procedure is converted into dry ice, and obtained after desorption potash aqueous solution is fed through heat exchanger, in which it is cooled to 20-30 °C, into the accumulator, from which it is returned to the absorption column. Invention also relates to an apparatus for producing carbon dioxide.

EFFECT: simpler and more cost-effective production of carbon dioxide from the stream of exhaust gases and high quality of the regenerate.

3 cl, 2 dwg, 1 ex