Effect of Co-combustion of Multiple Additives with Coal on NO Removal.

Abstract

Denitrification experiments of co-combustion of coal and additives were carried out in a horizontal tube furnace. The results showed that calcium acetate limited the production of NO2. The optimum calcination temperature of CTAB-Zr-TiO2 was 673 K. The denitrification efficiency reached up to 72.27%, and desulfurization efficiency reached 83.03% when corncob, calcium acetate, and CTAB-Zr-TiO2 were added. Corncob, calcium acetate, and CTAB-Zr-TiO2 all promoted coal combustion. The specific surface area of CTAB-Zr-TiO2 (55.50 m2/g) was the largest, which was more than 4.5 times that of pure TiO2 (12.20 m2/g). The denitrification process in the co-combustion of coal with multiple additives included a homogeneous reaction and heterogeneous reaction. The homogeneous reaction was that NO and NO2 were reduced to N2 by reducing gases produced in combustion. The heterogeneous reaction involved the reduction of NO and NO2 by coal char. The additives increased the specific surface area of the coal char and enhanced the activity of the heterogeneous reduction of NO and NO2. At the same time, the catalysis of alkali metal oxides in corncob and CTAB-Zr-TiO2 promoted the heterogeneous reduction of NO and NO2 by the coal char.