Review on post-combustion CO 2 capture by amine blended solvents and aqueous ammonia

Absorption/regeneration systems based on chemical solutions are considered a more appropriate option for postcombustion CO2 capture, with amine solvents being the most commonly utilized. First, this paper provides a systematic review of the mechanisms and performance of CO2 capture by blended solvents of amine-amine, amine-organic solutions, amine-inorganic solutions, and amine-ionic liquids. Furthermore, some process modifications that can reduce energy consumption and amine degradation during CO2 capture are discussed. As a promising and challenging absorbent, aqueous ammonia shows potential for simultaneous removal of CO2/NOx/ SO2, producing valuable byproducts like ammonium sulphate and ammonium nitrate fertilizers. Therefore, the current development of ammonia scrubbing techniques for CO2 capture and simultaneous removal of CO2/NOx/ SO2 is subsequently reviewed in terms of reaction mechanisms, process modifications, and application challenges. Finally, specific directions have been proposed for the future development of amine and aqueous ammonia scrubbing techniques, which are expected to provide meaningful guidance for CO2 capture by chemical absorption.