Predicted Solubilities of Methanol in Compressed Natural Gas at Low Temperatures and High Pressures

Abstract

Considerable attention has been given to the thermodynamic properties related to natural gas processing. Vapor-liquid equilibrium data and correlations for mixtures containing methane and other nonpolar molecules (and slightly polar gases) have been some of the more important tools for the natural gas process design engineers; however, less attention has been paid to the phase equilibrium properties of the compressed natural gases containing polar chemicals at low temperatures and high pressures. For example, methanol has been effectively used to remove water (and acid gases such as carbon dioxide and hydrogen sulfide) from natural gas [¹] prior to its subsequent liquefaction. For the rational process design of LNG (liquefied natural gas) or NGL feed preparation using methanol, methanol solubility data in the compressed natural gas are needed at various temperatures and pressures. The presence of acid gases in natural gas will also affect the solubility of methanol. Such experimental data at low temperatures and at high pressures are not available in the open literature.