Absorber Performance with High CO2

Previous studies of CO2 absorption mainly focused on coal-fired flue gas with 12% CO2. However, in a hybrid process combining amine scrubbing with membrane technology, the CO2 concentration in the flue gas may be enriched to 20%. This work simulates absorber performance at 12 to 20% CO2 with the Independence model for piperazine (PZ) in Aspen Plus (R). 5 molal (m) PZ was chosen as the solvent with a solvent rate of 1.1* L-min. To estimate the absorber performance in this range, a factorial design has been used to define the model inputs. Both in-and-out intercooling and pump-around intercooling have been simulated for the absorber. The model calculates the solvent rate, packing height, rich loading, and optimized position of intercooling for each case. Empirical correlations for rich loading and a semi-empirical correlation for normalized packing have been derived. When estimating real absorber performance, K-G equals k(g)(') measured in wetted wall column times a correction factor phi. For 99% removal, phi varies from 1.6 to 2.6. For 60% removal, phi varies from 0.6 to 0.8. Published by Elsevier Ltd.