NEW ABSORBING AGENT AND METHOD FOR ISOLATION OF SULFUR DIOXIDE FROM GAS FLOW, USING THIS AGENT Russian patent published in 2022 - IPC C01B17/60 B01D53/50 

FIELD: chemistry.

SUBSTANCE: group of inventions relates to the field of chemical technology, in particular to a new absorbing agent for isolation of sulfur dioxide from a sulfur dioxide-containing gas flow, as well as to a method for isolation of sulfur dioxide from a gas flow, using the specified new absorbing agent. An absorbing agent for isolation of sulfur dioxide from a sulfur dioxide-containing gas flow is presented, containing a suspension of solid salts, obtained by mixing of oxalic acid, citric acid, and potassium hydroxide in water, at a molar ratio in the range of 1 : 1.6÷4.8 : 4÷11, while a water content ranges from 35 to 50 % by wt., and concentration of citrates is from 2.0 to 2.8 mol/l. In another embodiment, a method for isolation of sulfur dioxide from a sulfur dioxide-containing gas flow is provided, including pre-purification of the sulfur dioxide-containing gas flow from sulfur anhydride, using a solution of potassium sulfite/bisulfite to obtain potassium sulfate; absorption of sulfur dioxide, at which the gas flow purified from sulfuric anhydride is brought into contact with the suspension of the absorbing agent to obtain a suspension of a loaded absorbing agent containing a solid phase of crystal salts of potassium, oxalic acid, and potassium metabisulfite, and gas purified from SO₂; evaporation of absorbed sulfur dioxide by treatment of the suspension of the loaded absorbing agent with water vapor; removal of vaporized sulfur dioxide with water vapor into a condenser refrigerator, where water vapor is condensed, and a vapor-liquid mixture is sent to a phase separator, from where concentrated sulfur dioxide is removed; regeneration of the absorbing agent; introduction of the regenerated absorbing agent to a stage of absorption of sulfur dioxide, wherein, at the start of the process, the absorbing agent is obtained by mixing of oxalic acid, citric acid, and potassium hydroxide in water, at a molar ratio in the range of 1 : 1.6÷4.8 : 4÷11, while a water content ranges from 35 to 50% by wt., and concentration of citrates is from 2.0 to 2.8 mol/l.

EFFECT: development of a new absorbing agent based on a mixture of polybasic carboxylic acids, characterized by an increased absorption capacity and a degree of regeneration, allowing isolation of sulfur dioxide from gas flows with a concentration of sulfur anhydride in the range from 0.1 to 100 vol.% to a residual content of sulfur dioxide in a gas flow to values meeting requirements of environmental legislation.

6 cl, 2 dwg, 6 tbl, 13 ex