Regeneration of FGD waste liquors: Production of ammonium and potassium sulfate mixed fertilizer. Quarterly technical report, July 1993--September 1993.

摘要

Regeneration of the Fe(sup II)-EDTA scrubbing liquors for simultaneous removal of SO(sub 2) and NO(sub x) in flue gas involves removing the nitrogen-sulfur (N-S) compounds accumulated in the liquor. In this paper, the authors investigated a simple regeneration process which selectively precipitates the N-S compounds as potassium salts and then hydrolyzes them to yield ammonium/potassium sulfate as a marketable byproduct. They believe this is the first report on precipitation and hydrolysis characteristics of the N-S compounds in actual waste scrubbing liquor. Precipitation of the N-S compounds was achieved by adding K(sub 2)SO(sub 4) to the scrubbing liquor. Effects of the amount of added K(sub 2)SO(sub 4) on the amount of removed N-S compounds, precipitated crystals, and the potassium left over in the scrubbing liquor were studied. Hydrolysis of the precipitated N-S compounds to ammonium sulfate was performed in a sulfuric acid environment. Effects of acidity, concentration of N-S compounds, and temperature on the hydrolysis are discussed. Analysis of the observed hydrolysis pattern showed that the reaction proceeded following first order kinetics in terms of N-S compound concentration.