Effect of solvent on CO2 absorption performance in the microchannel

The absorption performances of CO2 into 2-amino-2-methyl-1-propanol (AMP) solutions mixed with solvents water, ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) were investigated and compared in a T-junction microchannel. The absorption rate under different liquid flow rates (10-40 ml.h(-1)), gas/liquid flow rate ratios (0.5-10) and AMP concentrations (0.2-0.8 mol.L-1) was determined by the online photographic method. The dynamics (bubble and slug lengths, film thickness, recirculation frequency in slug, film-slug exchange and pressure drop) in the slug-flow region were analyzed and discussed. The results show that solvents affect the absorption rate with the order of AMP-water < AMP-EG < AMP-DEG < AMP-TEG, which is opposite to their solubility. The increased pressure drop and shorter bubble surrounded with thicker film are the dominant factors affecting the absorption rate, which increase the concentration driving of CO2 and film-slug mass exchange at the higher solvent viscosity respectively. Under current conditions, water is a good solvent candidate by joint consideration of absorption rate and energy consumption. This study provides guidance for solvent selection and manipulation of CO2 absorption in the microreactor. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

The absorption performances of CO2 into AMP solutions mixed with water, EG, DEG, and TEG were investigated and compared in a T-junction microchannel. The results show that solvents affect the absorption rate with the order of AMP-water < AMP-EG < AMP-DEG < AMP-TEG, which is opposite to their solubility. Increased pressure drop and shorter bubble surrounded with thicker film are the dominant factors affecting the absorption rate. Under current conditions, water is a feasible solvent choice.