The hybrid of amines is regarded as a promising alternative to MEA owing to its good performance on kinetics and thermodynamics for CO2 absorption. The primary/secondary amine can serve as absorption accelerator and the tertiary amine act as CO2 sinker and regeneration promoter. In this study, a novel hybrid comprising of N-methylcyclohexyamine (MCA) and N, Ndimethylcyclohexylamine (DMCA) was put forward. The absorption kinetics using DMCA-MCA for CO2 absorption was investigated in a wetted wall column. The results showed that the total mass transfer coefficient of DMCA-MCA approach 2.02×10-10 mol/cm2 ∙s∙Pa, which was 1.2-folder higher than 5M monoethanolamine (MEA) as the benchmark. Moreover, the CO2 absorption capacity of DMCA-MCA hybrid reached 3.94 mol/L, significantly higher than 2.70 mol/L of 5M MEA. The thermodynamics was evaluated in a high pressure reactor, implying that the total regeneration heat was 2.20 GJ/t CO2, which was much less than MEA (3.99 GJ/t CO2). The results can benefit for developing novel absorption technology with DMCA-MCA solvent with a rapider absorption rate, higher absorption capacity and lower heat duty for CO2 capture.
Keywords CO2 capture; hybrid amine; absorption rate; regeneration heat