Enhanced CO2 absorption and reduced regeneration energy consumption using modified magnetic NPs

Abstract

This study aimed to investigate the ability of nanofluids in improving CO2 absorption and reducing regeneration energy demand in a bubble column reactor in the presence of functionalized-magnetic NPs. The first step was to synthesize Fe3O4 nanoparticles (NPs), which were then functionalized with Aspartic-acid and Lysine. Next, to study CO2 absorption and stripping performances, the NPs with different concentrations were dispersed in an aqueous methyl diethanol amine (MDEA) solution (10 wt%). The investigation of CO2 absorption performance, CO2 loading and pH of all nanofluids were reported at different times of absorption experiments. The obtained results indicated that Fe3O4@Aspartic (Fe3O4@Asp) and Fe3O4@Lysine (Fe3O4@Lys) NPs improved CO2 loading up to 15.3% and 21.4%, respectively, as compared to Fe3O4 NPs. In addition, the functionalized-magnetic NPs showed more positive effects on CO2 desorption compared to bare Fe3O4. To show regeneration efficiency, the outlet gas flow rate and its CO2 concentration were measured and the CO2 loading and pH were determined at the end of the desorption experiment. The results revealed that at 70 °C, the CO2 loading was reduced by 58.9% and 55.1% applying Fe3O4@Lys and Fe3O4@Asp, respectively. Therefore, more energy could be saved in desorption process using functionalized magnetic NPs.