Preliminary application of batch downflow gas contactor (BDGC) as a novel unit operation for CO2 absorption

CO 2 absorption has the potential to significantly decrease carbon emissions, and this process is the most mature process in the world. In this study, a batch downflow gas contactor (BDGC) is experimentally utilised for the first time to capture CO 2 from a CO 2 +N 2 gas mixture. The goal was to achieve more than 90% CO 2 uptake using monoethanolamine (MEA) aqueous solution under various operating conditions, including solvent concentration, gas flow rate, and inlet CO 2 concentration. The effects of these parameters are investigated using design of experiment (DoE) approach. Due to the high turbulency at the top of the BDGC column, which results in a high mass transfer rate, this unit operation can achieve over 90% carbon capture level with a lower concentration of amine solution. Besides, a cost analysis was conducted for the scaled-up BDGC process. Considering an industrial base case, the BDGC column required to achieve the same level of carbon capture has a diameter of 0.63 m and a length of 5 m. The results indicate that the BDGC can be considered as a highly potential unit operation for carbon capture. Notably, the cost analysis revealed that this unit can be more cost-effective compared to conventional packed columns. Interestingly, the minimum and maximum cost for CO 2 absorption using BDGC was observed to be 13.84–49.74 US$/t CO 2 captured, respectively. • BDGC used for the first time to capture CO2, achieving over 90% CO 2 capture using MEA solution. • High mass transfer rate in BDGC enables efficient CO 2 capture with lower amine concentration. • CO 2 absorption using BDGC shows a cost of 13.84-49.74 US$/t CO 2 captured. • Scaled-up BDGC design offers significant potential for cost-effective, industrial-scale carbon capture.