Study On Equilibrium Thermodynamics Of Low-concentration Mine Gas Separation Based On Hydration

The determination of the phase equilibrium conditions of gas hydrate research is the basic means, which can provide basic physical properties datas of the application of gas hydrate. Hydration separation method is a new method to separate mine gas with characteristics of moderate conditions and high efficiency, which will have a broad prospect in research and application. The quick and sTablele hydrate formation is key to the application of this method, and adding chemical accelerators is an effective mean to accelerate hydrate formation, so the effects of a thermodynamic accelerator of tetrahydrofuran （THF） and tetrahydrofuran （THF）- sodium lauryl sulfate （SDS） binary solutions on the process of low-concentration mine gas hydration separation were deeply investigated and the mechanisms were discussed in this paper.The thermodynamic parameters of hydrate formation were investigated in nine reaction systems of adding THF by using visual gas hydrate equipments in this paper. By comparing experimental data and calculated values by improved Chen-Guo model, it was found that THF can improve thermodynamic parameters efficiently, and the larger the THF concentration, the better the improved effect if the concentrations of THF were less than 0.90 mol·L^-1. The hydration separation effects of three kinds of gas samples with CH₄ concentrations of 7.8%, 17.3% and 24.7% were investigated, respectively, and the results showed that the larger the THF concentration, the larger the partition coefficients of CH₄ between hydrate phase and gas phase, in the binary solutions, the higher concentration of SDS, the worse the separation, and the maximum coefficients were 2.28, 2.39 and 2.45, respectively. The highest concentrations of CH₄ in hydrate phase were 13.84%, 30.01% and 36.88%, respectively.Thirty groups of experiments were performed to investigate the determination of the phase equilibrium parameters to the multicomponent mine gas hydrates and the effects of accelerators on gas hydration separation, a batch of valuable data and images and the influence rules of THF and THF-SDS binary solutions on gas hydration separation were obtained. This study can provide theory references and practice bases for further study of mine gas hydration separation and purification.This paper has twenty-eight figures, seven tables and seventy-two references.