天然气水合物生成焓的测定(英文)

实验测定了在压力 2 0 0 0 k Pa和 670 0 k Pa条件下 ,含有甲烷、乙烷、丙烷和异丁烷等典型组成的天然气其水合物的生成焓。实验所用水合物是在微分扫描量热仪里直接生成 ,且在指定的压力下进行恒压温度扫描 ,同时测定水合物中的水气比和生成焓。其误差小于 1 .5 %。实验结果表明 ,在不同的实验压力条件下 ,水合物的生成焓与水气比变化较小

Measurement of the Molar Enthalpies of Formation of Natural Gas Hydrates

This paper reports the measurement of the molar enthalpies of natural gas hydrates for typical natural gas mixtures containing methane, ethane, propane and iso butane at pressures in the vicinity of 2 000 kPa and 6 700 kPa, in a multicell differential scanning calorimeter using modified high pressure cells. The natural gas hydrate was formed by cycling the solution in the vicinity of the ice point. The mass of hydrate formed was calculated from the measurement of the enthalpy of fusion of water after the hydrate was formed and after the hydrate was dissociated. The enthalpy of fusion of water and the enthalpy of gas hydrate dissociation were determined from the calorimeter response during a slow temperature scan at a constant pressure. The amount of gas released from the dissociation of the hydrate was determined from the volume change of the high pressure pump required to maintain the constant pressure, and the amount of the hydrate formed was determined from the measurement of the enthalpies of fusion of water before and after the dissociation of the hydrate. The occupation number (the ratio of the water to gas) and the enthalpy of the hydrate formation have an uncertainty of 1.5 %. The results show that the enthalpies of the hydrate formation and the occupation number are essentially independent of pressure.