Absorption characteristics of carbon dioxide into an O/W emulsion absorbent containing N-methylcyclohexylamine/2,6-dimethylpiperidine

• The optimum emulsion condition for lipophilic amine was 5000 RPM using Tween 80.
• The absorption rate of MCHA and DMPD emulsion absorbent were higher than MEA solution.
• The effective CO2 loading of MCHA and DMPD emulsion were higher than alkanolamine.

A novel absorbent was developed using an oil/water (O/W) emulsion absorbent with lipophilic amine. N-methylcyclohexylamine (MCHA) and 2,6-dimethylpiperidine (DMPD) were selected as the absorbents and Tween 80 was used as the emulsifier. The absorption rate and equilibrium were measured using a wetted wall column and vapor–liquid equilibrium apparatus, respectively, to investigate the carbon dioxide (CO2) absorption performance of each absorbent. The monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP) solutions were used for comparison. The absorption rate of CO2 into the emulsion absorbent was higher than that into the aqueous MEA solution. The CO2 loading ratio of the MCHA and DMPD were 0.87 and 0.72 at 313 K, respectively. Additionally, the effective CO2 loading in MCHA and DMPD were 0.31 and 0.4 CO2/mol amine respectively, which is higher than that in the MEA and AMP solutions. These results show that the emulsion absorbent containing the lipophilic amine may show effective CO2 absorption performance.