Comparison of Capture Efficiencies of Carbon Dioxide by Fine Spray of Aqueous Ammonia and MEA Solution

In order to investigate the feasibility of using fine spray method to capture CO2 and compare the CO2 capturing capabilities of new absorbent—aqua ammonia and conventional absorbent —MEA, experimental studies on CO2 capture were carried out in a spray scrubber, in which the fine spray of MEA and ammonia solution respectively contacted reversely with the artificial flue gas. The effects of different operation parameters, such as absorbent concentration, liquid flow rate, total gas flow rate and initial temperature, on CO2 removal efficiency were investigated. The experimental results show that using fine spray method to capture CO2 can reach a very high CO2 removal efficiency (above 96.0%), and the higher concentration and flow rate of the aqueous ammonia or MEA solution are beneficial to promote the CO2 removal efficiency. With the increase of the absorbent flow rate, the CO2 removal efficiency of using MEA can increase from 36.9% to 63.2%, this increment is higher than that of using aqueous ammonia as absorbent. On the other hand, with increasing the total gas flow rate, the CO2 removal efficiencies of using MEA solution and aqueous ammonia decrease 16.5% and 17.3%, respectively. However, under comparable conditions and with the same absorbent concentration, the CO2 removal efficiency of using aqueous ammonia is higher than that of using MEA solution.