Effect of reactor geometry on aqueous ammonia-based carbon dioxide capture in bubble column reactors

Abstract

Capture of carbon dioxide (CO2) from combustion flue gas by aqueous ammonia has been demonstrated as an effective and promising technology. To examine the effect of reactor geometry on ammonia-based CO2 capture performance, a series of bubble column reactors with same volume of working liquid but varied geometry (liquid height-to-diameter ratios H/D=0.93, 2.04 and 3.98) were designed to investigate CO2 capture efficiency with ammonia under different reaction conditions. It is found that reactor geometry characterized by liquid height-to-diameter ratio plays an important role in CO2 capture efficiency as it is associated with gas holdup time in reactors. CO2 capture efficiency increases as liquid height-to-diameter ratio increases. Under the same experimental conditions, the maximum CO2 capture efficiency can increase by up to 7%. Besides, CO2 capture efficiency has positive correlation with the ammonia concentration and reaction temperature whereas has negative correlation with the CO2 inlet concentration and flue gas flowrate.