Selective Mechanisms of WO3 Catalyzing CO2 Desorption and Inhibiting NH3 Escape

Abstract

The high regeneration energy consumption and ammonia escape in the ammonia regeneration process are regarded as the main barriers for the commercial application of CO2 capture technology based on ammonia solutions. Metal oxides can enhance the CO2 desorption process and inhibit the ammonia escape at the same time, which can reduce the energy consumption of CO2 capture systems. Both ammonium carbamate (NH2COONH4) and ammonium bicarbonate (NH4HCO3) are examined as the rich ammonia solution. The results show that when the concentration of tungsten trioxide (WO3) was 0.1 mol/L, the CO2 desorption efficiency could be promoted by 18.8% and the ammonia escape efficiency could be reduced about 14%. The mechanism by which WO3 increased the CO2 desorption process was clarified by XRD analysis as the production of ammonium tungstate. In addition, the other nine metal oxides exert no catalytic influence on the regeneration process.