Selective Mechanisms of WO3 Catalyzing CO2 Desorption and Inhibiting NH3 Escape

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.

Automated summary

The high energy consumption and ammonia escape during the ammonia regeneration process are the main barriers for the commercial application of CO2 capture technology using ammonia solutions. Metal oxides, particularly tungsten trioxide (WO3), have been found to enhance CO2 desorption and inhibit ammonia escape, thereby reducing the energy consumption of CO2 capture systems. Experimental results showed that a concentration of 0.1 mol/L of WO3 increased the CO2 desorption efficiency by 18.8% and reduced the ammonia escape efficiency by about 14%. XRD analysis confirmed that the mechanism behind the enhanced CO2 desorption process was the production of ammonium tungstate, while other metal oxides had no catalytic influence on the regeneration process.