Double-Alkali Gypsum Flue-Gas Desulphurisation Process

摘要

The double-alkali gypsum flue-gas desulfurization process (concentrated active sodium mode) was investigated on a pilot-plant scale downstream of a test boiler fired with heavy oil, in order to obtain design and operating data. A solution of sodium sulfite was used as soluble absorbent for SO2. The absorbent was regenerated with lime in a separate reactor. Calcium sulfite and calcium sulfate were coprecipitated during the regeneration. The coprecipitates were suspended in water and oxidized by air to form gypsum. The gypsum generated in the double-alkali process was similar to that obtained from wet lime/limestone-gypsum processes. It can be concluded that the double-alkali gypsum process is much more complicated than the lime/limestone-gypsum flue-gas desulfurization process.