A Combined Experimental and Computational Study on the Shuttle Mechanism of Piperazine for the Enhanced CO 2 Absorption in Aqueous Piperazine Blends

作者：Qinlan Luo, Qulan Zhou, Bin Feng, Na Li, Shicheng Liu · 发表于：Industrial & Engineering Chemistry Research · 年份：2022 · DOI：10.1021/acs.iecr.1c04123 · 被引用次数：38 · 研究领域：Carbon Dioxide Capture Technologies、Membrane Separation and Gas Transport、Phase Equilibria and Thermodynamics

Piperazine (PZ) blends containing PZ and monoethanolamine (MEA)/ N -methyldiethanolamine (MDEA)/2-amino-2-methyl-propanol (AMP) were experimentally and computationally investigated to analyze their potential capabilities for CO 2 capture, and the shuttle mechanism of PZ for enhanced CO 2 absorption were verified. In experiments, the concentration of both PZ and MEA/MDEA/AMP were varied to show the effect of concentration ratio and the influence of amine components on the CO 2 absorption rate and capacity. Experimental results showed that all the PZ blends possessed high absorption rates and large absorption capacities. To further understand the interaction behavior of amines/products and possible reaction pathways, both qualitative and quantitative 13 C NMR analyses were conducted. The results indicated the conversion between absorption products, which can release free PZ to capture CO 2 and consequently improve the absorption performance. Moreover, the static quantum mechanical calculations and ab initio molecular dynamics (AIMD) simulations combined with metadynamics sampling were conducted to evaluate the thermodynamic stability of absorption products and kinetically favorable key elementary reactions in PZ blends. This study highlights an accurate description of the shuttle effect of PZ for the enhanced CO 2 capture by PZ blends.