The Piperidine-H2O-CO2 System for Sequestering Highly Concentrated CO2

Abstract

The post-combustion capture (PCC) process using amines is one of the most representative technologies for separating CO2 from huge CO2 emisions. However, the achievement of reasonable costs for capturing CO2 requires continuous studies on absorbent development, process optimization, and energy saving. Among these, the absorbent development is the most essential factor in reducing the operating cost and equipment cost of the PCC process. In this study, piperidine (PD) solution is used as an alternative absorbent to overcome the disadvantage of commercial monoethanolamine (MEA) solution. The absorption rate, absorption capacity and regeneration energy of PD solution were measured to confirm its performance as an alternative absorbent. It was found that PD solution shows key advantages, compared with MEA solution. First, the overall mass transfer of CO2 in PD solution was 2.69 times faster than in MEA solution at 313 K. Second, PD solution was capable of absorbing 1.5 times more of CO2 than MEA solution. Third, the reboiler heat duty of PD solution showed 1.16 times better energy-efficiency than that of MEA because the sensible heat of PD was 75.8 kJ·mol−1 lower than that of MEA. From these results, PD solution is deemed to be a good alternative absorbent to replace MEA solution.