Carbon dioxide recovery from carbonate solutions using bipolar membrane electrodialysis

Abstract

Process design and cost estimation were conducted for CO2 recovery by liquid absorption with alkaline solution, coupled with bipolar membrane electrodialysis for CO2 gas separation and alkaline solution regeneration. The electrodialysis performances and power consumption for CO2 recovery and alkaline solution regeneration were examined using laboratory-scale electrodialysis equipment under various conditions; degree of CO2 absorption, CO2 recovery ratio, alkaline concentration, and type of cation exchange membrane. The total cost of CO2 recovery was estimated for the treatment of CO2 emitted from a 400MW coal-fired thermal power plant. The minimum cost for the optimum condition was about US$180 per ton-CO2 removed, which is higher than that for the conventional process using amine absorption and thermal desorption. However, a sensitivity analysis indicates that the overall cost could be significantly reduced if the cost of membranes was reduced.