Volume 33: CCUS Technologies for the Carbon Neutrality: Part I

A low energy consumption ammonia based CO2 capture process with bipolar membrane electrodialysis Zhengyuan Song, Guogang Sun

Abstract

Post combustion capture using chemical absorption is one of the most mature technologies, which can effectively reduce CO2 emissions from plants. But it usually comes with the cost of high energy consumption. Aiming to reduce the regeneration energy consumption of post combustion CO2 capture technology, a novel ammonia based CO2 capture process with bipolar membrane electrodialysis(BMED) and CO2 regeneration reactor is designed. In the CO2 regeneration reactor, the CO2 loaded by rich solvent is completely released and collected due to the reactions between the rich solvent and strong acid. After that, energy consumption of the BMED unit is effectively reduced because there is no bubble formation in the cell during the electrodialysis process. The performance of conventional amine based process and the novel process is evaluated by simulation and calculation. Result shows that the CO2 regeneration energy consumption of the novel process is as low as 1.80MJ/kgCO2, which is much lower than that of the conventional process(3.91MJ/kgCO2). Given the volatilization of the NH3, the treatments of escaped NH3 in the novel process is discussed. When the value-added products is considered, sent the escaped NH3 washing solution to the desulfurization part as absorbent may be a better choice than recovering NH3 with heating. With the development of the membrane technology, the energy consumption of the novel process will be further reduced. If combined with renewable energy technology, it is expected to be a new CO2 capture technology.

Keywords CO2 capture, aqueous ammonia, bipolar membrane, energy consumption