Effects of Metal Oxides on Ammonia Escape and Carbon Dioxide Desorption during Ammonia Decarbonization Regeneration

The high energy consumption during the regeneration process is an important issue that currently limits the application of ammonia decarbonization technology. In this work, four solid metal oxides are proposed to be added in ammonia-rich solutions during regeneration for reducing energy consumption. The effects of the metal oxide type, heat duty, and CO2 loading on CO2 regeneration and NH3 escape are investigated. The results show that WO3 enhances the desorption of CO2 regeneration while inhibiting the escape of NH3 compared to other oxides. The CO2 regeneration rate increased by 68.9%, and the ammonia escape reduced by 36.3% with the addition of 4 wt % WO3 at 90 °C. Based on the CO2 loading rate and the product characterization, a possible mechanism for the metal oxide assisted ammonia regeneration process is analyzed, where WO3 can be used as an additive during the regeneration process of ammonia decarbonization to reduce the activation energy of the regeneration reaction and enhance CO2 desorption while suppressing NH3 escape.