Determination and Study of the Solubility of Methane in Mixtures of Methanol plus Various Hydrocarbons at High Pressures

Abstract

It is known that the use of natural gas as a vehicular fuel is advantageous; however, the drawback of this application is the storage limitations of natural gas. One method for storing natural gas at moderate temperatures and pressures is to dissolve it in organic mixtures. In this paper, an apparatus for measuring gas solubility in liquids under high pressures was used. The solubilities of methane in methanol + n-hexane, methanol + n-heptane, and methanol + cyclohexane at 303.15 K and in methanol + benzene and methanol + methylbenzene at 288.15 K and 303.15 K were measured. The experimental pressures are up to 12.0 MPa. The new solubility measurements are believed to have uncertainties of 0.002 (mole fraction). Meanwhile, the molar volumes of liquid-phase mixtures at high pressures were determined and well-estimated by the Aalto−Keskinen model. Because of the polarity of methanol, the PRSV equation of state with the Huron−Vidal mixing rule was used to estimate the equilibrium data for methane + methanol + hexane, methane + methanol + heptane, and methane + methanol + cyclohexane systems as well as to correlate the data for methane + methanol + benzene and methane + methanol + methylbenzene systems. The average absolute deviations (AAD) of the correlation were 3.0 % and 1.9 %, respectively.