Energy Minimization and Ammonia Abatement for CO₂Capture Using a Blend of Ammonia and 2-Amino-2-Methyl-1-Propanol Solution

An aqueous ammonia based CO2 capture offers several advantages over the conventional monoethanolamine (MEA) solvent, including a high CO2 loading capacity, low stripper heat duty, a lower degradation rate of solvent, low equipment corrosion, and the ability to capture multipollutants. However, in order to make an aqueous, ammonia-based CO2 capturing process economically feasible, attention must be paid to the following issues: ammonia slip due to the high evaporation rate of ammonia, energy input for CO2 regeneration, and CO2 removal efficiency improvements. In conventional, aqueous ammonia-based CO2 capture, the process either needs to operate at very low temperatures or must include wash-water columns to mitigate ammonia slips, which increase the capital and operational costs of the system. In this paper, a blended solution of 2-amino-2-methyl-1-propanol (AMP) and ammonia was used to analyze the CO2 capture efficiency, ammonia slip, and stripper heat duty. Our results show that, using the blended (30 wt.% AMP + 3 wt.% NH3) solution for CO2 capture, the ammonia slip was reduced by 64% at a lean CO2 loading of 0.07, CO2 capture efficiency was increased by 17.2%, and the heat duty requirement for CO2 regeneration was reduced by 80% at a stripper inlet temperature of 60°C. Moreover, the loss of AMP due to evaporation was 0.042 kg/day.