Structure Characteristics and Hot-Coal-Gas Desulfurization Properties of Zn-Based Sorbents Supported on Mesoporous Silica with Different Pore-Arrangement Patterns: A Comparison Study
2021
Wu, Mengmeng | Li, Qiaochun | Wang, Xiaowen | Mi, Jie
Ordered mesoporous MCM-41 (two-dimensional (2D) hexagonal pore arrangement) and MCM-48 (three-dimensional (3D) cubic channel arrangement) with similar pore sizes and surface areas were selected for comparison when used as support for Zn-based sorbents for hot coal gas desulfurization. Compared to that of Zn/M48 (MCM-48-supported desulfurizer), the adsorption capacity of Zn/M41 (MCM-41-supported sorbent) increases by 24.4–56.3%. The initial reaction rate constants of Zn/M41 are 1–13 times greater than those of Zn/M48. These are correlated to the structural features of sorbents. Zn/M41 has a large wall thickness of the framework, suggesting higher thermal stability. Furthermore, the sorbent particles and ZnO grains in Zn/M41 are both smaller in size, which facilitates contact between H₂S and ZnO. Additionally, Zn/M41 possesses a large surface area and pore volume, beneficial for the diffusion of H₂S through sorbents. The analysis of the atmospheric effects reveals that there is a stronger synergistic effect of CO and H₂ on desulfurization over Zn/M41.
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