Synergistic Enhancement of Low-Concentration Gas Hydrate Purification by Designing a DIOX Composite with 13X and Modified 13X

Hydrate-based gas separation (HBGS) technology is an effective strategy for treating low-concentration coal mine methane (CMM). However, gas hydrate formation involves three phases (gas, liquid, and solid) and is a complex crystallization process. The mass and heat transfer, which suffers from obstacles, has been demonstrated to result in a prolonged induction period, a reduction in formation rates, and an augmentation in driving forces. Herein, the development of techniques to promote the kinetics and thermodynamics of the gas hydration reaction is needed. In this work, the modified zeolite porous material was mixed with 1,3-dioxolane (DIOX) as a thermodynamic promoter, and the impact on the performance of gas-hydrate-based separation and purification of low-concentration coal mine gas was investigated. The modified 13X zeolite demonstrates significant advantages in hydrate-based separation performance: at a mass percentage of only 0.10 wt %, it achieves a standardized gas consumption rate of 83.920 mol·min–1·m–3 and a CH4 recovery rate of 89.47%. Theoretical analysis indicates that modified 13X possesses a rich mesoporous structure, significantly enhancing the number of nucleation sites and mass transfer efficiency. Overall, the synergistic effect of modified 13X and DIOX provides a novel and efficient means of high-efficiency, low-concentration gas purification.