Evaluation of Some Regenerate Sulfur Dioxide Absorbents for Flue Gas Desulfurization

Abstract

The body of information presented in this paper is directed to chemical engineers in the field of environmental control technology. The vapor pressure of sulfur dioxide above aqueous solutions of citric acid, glycolic acid, 1-methyl-2-pyrrolidone, and ethylenediamine, as well as above pure tri-n-butyl phosphate, 1-methyl-2-pyrrolidone, and water were measured for possible application as absorbents for regenerable flue gas desulfurization systems. Results were used to estimate the steam rate and principal costs of processes using 11 of the absorbents. For sulfur dioxide absorption followed by indirect steam stripping, a 9.75 % ethylenediamine solution had the lowest steam rate. The ethylenediamine steam rate was 25% of the next two lowest steam rates, which were for pure l-methyl-2-pyrrolidone and citric acid solution. However, cost of losses of ethylenediamine vapor up the stack were excessive, indicating that a higher boiling point amine would be preferable.