Optimizing the cask effect in multicomponent natural gas purification to provide high methane productivity
Yuxin Chen, Yunjia Jiang, Jiahao Li, Xianghao Hong, Hao‐Fei Ni, Lingyao Wang, Nan Ma, Mingman Tong, Rajamani Krishna, Yuanbin Zhang
Abstract
Abstract The efficient separation of CH 4 from natural gas containing C 2 H 6 and C 3 H 8 impurities is an important topic. Previous work on the separation of CH 4 /C 2 H 6 /C 3 H 8 mixtures often focuses on the C 3 H 8 /CH 4 selectivity, inadvertently sidelining the critical importance of C 2 H 6 /CH 4 selectivity. This oversight results in reduced CH₄ productivity and compromised separation efficiency, a phenomenon often termed as the “cask effect.” Herein, we fine‐tune the interrelationship between thermodynamics and kinetics, targeting enhanced CH 4 production. A synergistic thermodynamic–kinetic C 3 H 8 /CH 4 and C 2 H 6 /CH 4 selectivity is achieved using dynamic breakthrough experiments, underpinned by the stable metal–organic framework TIFSIX‐Cu‐TPA. The CH 4 productivity in TIFSIX‐Cu‐TPA is up to 5 mmol g −1 , surpassing most of the popular materials. Detailed density functional theory and molecular dynamics computational insights reveal a counteractive thermodynamic–kinetic relationship, proving pivotal for the simultaneous breakthrough of C 2 H 6 and C 3 H 8 under optimal conditions. Moreover, precise adsorption sites of C 2 H 6 and C 3 H 8 are clearly determined through in situ single‐crystal structures.