Mechanism of CO2 capture by ethanol-biochar functionalized cross-linking enhanced ammonia

Abstract

CCUS technology is an important means to achieve carbon neutralization of energy utilization, in which the ammonia CO2-capture method is a relatively mature technology, with some problems (such as low CO2 absorption efficiency and serious ammonia escape). An ethanol/biochar synergistic ammonia carbon capture technology is proposed, and the mass transfer coefficient is studied by wetted-wall column, so as to assist in proving that biochar and ethanol have synergistic effect on the absorption of CO2 by ammonia. The simulation shows that the micropores in biochar adsorb and enrich CO2, the mesopores and macropores diffuse and transport CO2, and dynamically retain free NH3, thereby enhancing the mass transfer capacity of CO2 in the carbon capture system. And the experiment shows that the mass transfer efficiency of biochar-ethanol to the reaction solution is increased by 15.4%, which is higher than that of ethanol (7.1%),but biochar can make ammonia escape seriously. If the ammonia concentration can be maintained constant, the enhancement effect of the pore structure of biochar on the diffusion of CO2 into ammonia will provide a new direction for the improvement of CO2 capture by ammonia method.