瓦斯水合物相平衡测定及分解热计算

Measurement of phase equilibrium and calculation of dissociation heat of mine gas hydrate

为探究瓦斯水合物相平衡条件及其分解热特征,利用瓦斯水合物相平衡实验装置结合图形法研究了CH_4—N_2—O_2瓦斯混合气在纯水体系及TBAB(四丁基溴化铵,0.2mol/L)添加剂体系的水合物相平衡条件,将纯水体系下瓦斯水合物相平衡压强实验值与Chen-Guo模型计算值进行对比,基于Clausius-Clapeyron方程计算了瓦斯水合物分解热.结果表明:瓦斯水合物相平衡条件随着CH_4浓度的升高变得更加温和,TBAB可显著改善瓦斯水合物相平衡条件,使水合物相-气相边界向高温低压区域转移;相同温度下,2种瓦斯混合气在纯水体系生成水合物的相平衡压强实验值均低于Chen-Guo模型计算值,相对误差分别为0.18,0.23;水合物分解热随着瓦斯中CH_4浓度的升高而增大,TBAB体系瓦斯水合物分解热远大于纯水体系.

In order to investigate the phase equilibrium and dissociation heat characteristic of gas hydrate, the phase equilibrium conditions of gas hydrate which CH4-N2--／O2 gas mixture in pure water system and TBAB（0. 2 mol/L） system were studied. The graphics method and phase equilibrium experimental device for gas hydrate were used. The experimental values of the equilibrium pressure of gas hydrate in pure water system were compared with those calculated by Chen-Guo model. The decomposition heat of gas hydrate was calculated based on the Clausius-Clapeyron equation. The results show that the gas hydrate phase equilibrium conditions become more moderate with the increase of CH4 concentration. TBAB can remarkably improve the phase equilibrium conditions of gas hydrate, then make the boundary of hydrate phase-gas phase shift to the area which higher temperatures and lower pressures. The experi- mental data of phase equilibrium pressure were lower than the calculation data by Chen-Guo model for the two kinds of gas mixture at the same temperature in pure water system, the relative errors were 0.18 and 0.23. The decomposition heat of gas hydrate inereaseing with the rise of CH4 concentration, the decomposition heat of gas hydrate in TBAB system was much larger than in pure water system.