Removal of sulfur dioxide from waste gases

摘要

Sulfur dioxide is removed from waste gases such as stack gases by contacting the gas stream with free tertiary amines having basic strengths greater than about pK 5 to form a coordinate covalent complex of the amine and the sulfur dioxide. The sufficiently stable complex is than thermally regenerated to liberate the sulfur dioxide in one stream, to provide the residual gases in another stream, and to provide the regenerated tertiary amine for collection and reuse in a subsequent sulfur dioxide cleanup step. The coordinate covalent complex reacts with even very small concentrations of sulfur dioxide to effectively reduce the sulfur dioxide to detectable zero levels. The presence of carbon dioxide in waste gas streams does not interfere with the efficient cleanup because the selected tertiary amine does not react with the carbon dioxide.