SELECTIVE CATALYTIC-OXIDATION OF NH3 IN GASIFICATION GAS .2. OXIDATION ON ALUMINUM-OXIDES AND ALUMINUM SILICATES

In this study the ability of various acid catalysts to selectively oxi dize NH3 to N-2 was examined in synthetic gasification gas, when O-2 a nd NO simultaneously or O-2 or NO alone were added to the gas. If no o xidizers were added to the gas, all catalysts were inert and no reduct ion of NH3 took place. With aluminum oxide 95% NH3 reduction took plac e, when O-2 and NO were added simultaneously to the gas at 400 degrees C. Also aluminum silicates and montmorillonite were effective. Genera lly, NH3 conversion was always decreasing when the temperature was inc reasing. At low temperature, N2O formation was detected, which was ret arded at high temperature. Only a small amount of HCN was formed, when temperature was above 600 degrees C. Adding NO alone to the gas did n ot reduce the NH3 content of the gas. With O-2 addition alone, 50-60% NH3 reduction was achieved at a very narrow temperature window of 600- 700 degrees C.