Evaluation of Some Regenerable Sulfur Dioxide Absorbents for Flue Gas Desulfurization

摘要

The vapor pressure of sulfur dioxide above aqueous solutions of citric acid (2-hydroxy-1,2,3-propanetricarboxylic acid), glycolic acid (hydroxyacetic acid), 1-methyl-2-pyrrolidone, ethylenediamine (1,2 diaminoethane), and diethylenetriamine (2,2' diaminodiethylamine), as well as above pure tri-n-butyl phosphate, 1-methyl-2-pyrrolidone, and water, were measured for temperatures from 46.2 exp 0 C to 91.1 exp 0 C for possible application to regenerable flue gas desulfurization systems. Sulfur dioxide loadings in the absorbent ranged from 3.1 x 10 exp -5 to 5.27 x 10 exp -1 g/g. Measurements were made in a laboratory apparatus using N sub 2 /SO sub 2 mixtures. Results were used to estimate the steam rate and principal costs of processes for 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 lowest steam rate, which was for 100% 1-methyl-2-pyrrolidone. However, cost of losses of ethylenediamine vapor up the stack were excessive, indicating that a higher-boiling-point amine would be preferable. (ERA citation 07:049087)