Effect of combustion gas components on electrochemically promoted CO2 capture performance of Pt/K-βAl2O3 at bench scale

Abstract

Due to the continuous increase in CO2 atmospheric levels resulting from fossil fuels combustion, it is necessary to develop new, more efficient and less-energy intensive processes, that allow economically and selectively separate CO2 without the negative impact of co-existing gases (H2O, SO2, NO, etc.). This work presents a bench-scale study of the effect of combustion gas components on the electropromoted CO2 capture performance of an easily scalable Pt/K-βAl2O3 tubular electrochemical system, at high flow rates and in the presence of representative amounts of O2, H2O, SO2, NO and N2O. On the basis of previous mechanistic and spectroscopic studies, cyclic voltammetry studies showed that the system is able to capture CO2, not only by electropromoted adsorption but also as carbonates/bicarbonates by potassium ions electrochemically supplied to Pt surface. CO2 capture is enhanced in the presence of O2 and H2O. The CO2 capture behaviour of the system is almost unaffected by the presence of N2O. SO2 poisons CO2 capture, whereas the presence of NO appears to considerably hinder CO2 capture. The Pt/K-βAl2O3 system can be regenerated, allowing CO2 separation, by electrochemical decomposition of previously stored compounds without increasing temperature, with the consequent energy saving.