Multi-field synergy study of CO₂ capture process by chemical absorption

Carbon dioxide capturing from the flue gas of power stations is an effective way to mitigate the global warming. In order to predict the performance from startup to stable operation in CO₂ absorption process, a multi-field synergy model was developed based on CO₂ capture process in a packed column by means of monoethanolamine (MEA). The model suggests that the integral diffusion-reaction coefficient plays an important role in the diffusion, fluid flow, heat transfer and chemical reaction processes. The influences of the fluid flow, heat transfer and chemical reaction can be justified using corresponding synergy numbers, quantifying multi-field interactive dynamic characteristics of the CO₂ capture process. The simulation shows a good agreement compared with data in the literature. The results show that the packing Reynolds number can be used as a criterion to choose the proper packing. The less the Reynolds number is, the more efficient the reaction absorption is. The average synergy number F_dc would be decreased by 20% with 6 K temperature drop and be descended by 7% with the 2.5% solvent weight percentage increment, which improved the efficiency of CO₂ capture by about 5% and 14%, and lowered the energy consumption by about 5%. The average synergy number F_dh would be decreased by about 8% with the 0.062 mol/molMEA lean solvent loading increment, which improved the efficiency by about 15% and lowered the energy consumption by 5%. After comparing with CMR-2, Raschig rings, Berl saddles and Pall rings, the 33% less average synergy number F_df of the CMR-2 packing with about 5% drop in energy consumption yields the highest efficiency of 71%, which is 10% higher than that of the Berl saddle packing. The results indicate that the proposed multi-field synergy model is an effective way to intensify the capture process as a guideline with the priority of precision and simplicity.