The Study On Methane Solubility In Methanol And Hydrocarbon Mixing Solvents At High Pressures

With the improvement of environment consciousness and development of vehicles, relatively clean and economical natural gas vehicles become the emphasis of research. The very urgent problem of natural gas vehicle is how to store natural gas economically and efficiently. Dissolving natural gas in appropriate solvents maybe an effective way for putting natural gas vehicle in wide use. Some fundamental researches were done to select the ideal solvents for natural gas in the paper.In order to tie in with the development of methanol vehicles, ethanol vehicles and natural gas vehicles, methanol mixing with n-hexane, n-heptane, benzene, toluene, cyclehexane, gasoline and ethanol-gasoline were selected as solvents separately. The solubilities of methane in these different kinds of mixed solvents at high pressures were measured by a set of experiment apparatus for measuring gas solubility under high pressures systematically. The PRSV EOS coupled with different mixing rules were adopted to calculate the ternary GLE data of methane-methanol-hydrocarbon polar systems under high pressures by correlation. And the modified method based on activity coefficient and the EOS combined with associated theory were used to calculate the experimental data. It shows that the calculation result of the modified method based on activity coefficient is not as good as that of the PRSV EOS. And when the associated theory was used to EOS, the precision of calculation was improved greatly.In addition, the solubilities of methane under high pressures in benzene -cyclehexane, benzene-n-heptane, cyclehexane-n-heptane and gasoline were determinated and the experimental data were calculated by PR EOS. It indicates that the ternary GLE data can be well estimated by the method using binary GLE data. PR EOS and A-K model were both used to calculate the molar volumes of liquid phase under high pressures for experimental systems. Besides, the A-K model was modified in order to estimate data of the systems containing alcohols more accurately. It shows that it is feasible to dissolve NG in solvents because by this means the energy storage density can be increased and the storage pressure can be decreased. In a word, the methane solubilities in different mixed solvents under high pressures were determinated. It provided the necessary data for practical application. Some calculation methods were put forward; it can be used to design the natural gas vehicle fuels containing solvents. At the same time, the theory of phase equilibria and the calculation methods were advanced.