Method for purifying gases
First Claim
1. A method of removing SO2 from a gas, comprising contacting the SO2 containing gas with an aqueous solution of dimethyl sulfoxide while maintaining the pH of the aqueous solution acidic to dissolve SO2 in the aqueous solution of dimethyl sulfoxide and thereafter reacting the dissolved SO2 with alkaline earth metal ions to form a solid alkaline earth sulfate or a solid alkaline earth sulfite or mixtures thereof.
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Abstract
A method is provided for removing sulfur dioxide and carbon dioxide out of gases from, for example, the combustion of sulfur containing fossil fuels. The sulfur dioxide and carbon dioxide contaminated gas is first contacted with an aqueous solution containing dimethyl sulfoxide and alkaline earth metal ions, wherein the aqueous solution is at an acidic pH, for example, at a pH of from about 2 to about less than 7, so that the sulfur dioxide in the gas is dissolved in the aqueous solution and, subsequently, reacts with the alkaline earth metal ions to form alkaline earth metal sulfates and alkaline earth metal sulfites. The gas is then contacted with an aqueous solution containing dimethyl sulfoxide and alkaline earth metal ions, wherein this aqueous solution is at a pH that is greater than 7 so that the carbon dioxide in the gas is dissolved in the aqueous solution and, subsequently, reacts with the alkaline earth metal ions to form alkaline earth metal carbonates. The alkaline earth metal sulfates/sulfites and alkaline earth metal carbonates are separated from the solution. The source of the alkaline earth metal ions may be from cement waste or limestone.
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Citations
23 Claims
- 1. A method of removing SO2 from a gas, comprising contacting the SO2 containing gas with an aqueous solution of dimethyl sulfoxide while maintaining the pH of the aqueous solution acidic to dissolve SO2 in the aqueous solution of dimethyl sulfoxide and thereafter reacting the dissolved SO2 with alkaline earth metal ions to form a solid alkaline earth sulfate or a solid alkaline earth sulfite or mixtures thereof.
- 9. A method of removing CO2 from a gas, comprising contacting the CO2 containing gas with an aqueous solution of dimethyl sulfoxide while maintaining the pH of the aqueous solution basic to dissolve CO2 in the aqueous solution of dimethyl sulfoxide, and reacting the dissolved CO2 with alkaline earth metal ions to form solid alkaline earth CO3.
- 14. A method of removing SO2 and CO2 from a gas containing CO2 and SO2, comprising contacting the gas containing CO2 and SO2 with an aqueous solution of dimethyl sulfoxide at a pH less than 7 to dissolve SO2 in the aqueous dimethyl sulfoxide solution, reacting the dissolved SO2 with alkaline earth metal ions to form solid alkaline earth sulfate or alkaline earth sulfite or mixtures thereof, separating solid alkaline earth sulfate or alkaline earth sulfite from the aqueous dimethyl sulfoxide, thereafter contacting the gas containing CO2 with an aqueous solution containing dimethyl sulfoxide at a pH greater than 7 to dissolve CO2 in the solution containing aqueous dimethyl sulfoxide contacting, the dissolved CO2 reacting with alkaline earth metal ions to form solid alkaline earth CO3, and separating solid alkaline earth carbonate from the solution.
Specification