Experimental Study of Ammonia-based Post-combustion CO2 Capture Process Using Fibrous Tower Packings: Capture Efficiency and Conditions

Abstract

Aqueous ammonia is a promising alternative solvent for the post-combustion CO₂ capture technology due to its high CO₂ removal capacity, low material costs and regeneration energy. However, its high volatility and low reactivity to CO₂ limit its application. Therefore, more effort is still needed to improve ammonia-based CO₂ capture process. In this work, the performance of CO₂ capture in a packed tower using the ammonia solution and fibrous packing was experimentally investigated. The effects of key operating factors, such as packing type, packing height, liquid-gas (L/G) ratio, aqueous ammonia concentration and pH of absorbent, on the CO₂ removal efficiency, CO₂ capture capacity, and outlet gaseous NH₃ concentration have been revealed. The CO₂ capture efficiency was greatly improved when using the fibrous packing. Of the operating factors investigated, the one that had a greater effect on CO₂ capture was the gas flow rate; the lower the gas flow rate, the higher the CO₂ capture efficiency and the lower the ammonia evaporation. Considering the CO₂ capture efficiency and ammonia evaporation, an L/G ratio ≤ 5 and a superficial velocity ≤ 5.1 cm/s could be recommended.