A study on the solubility of heavy hydrocarbons in liquid methane and methane containing mixtures.

Abstract

The solubilities of the hydrocarbons n-butane, n-pentane, n-hexane, n-octane, and n-nonane in liquid methane and of n-hexane in the mixed solvents of methane and ethane and of methane and propane were obtained using a forced vapour recirculation apparatus. The liquid phase was sampled and analysed by gas chromatography. Liquid concentration ranges from 28.30 mole percent at 113.3K to 81.15 mole percent at 129.K for n-butane; from 5.09 mole percent at 123.4K to 41.19 mole percent at 131.25K for n-pentane; from 1.20 mole percent at 149.K to 17.95 mole percent at 166.2K for n-hexane; from 0.04 mole percent at 156.3K to 0.64 mole percent at 179.7K for n-octane; and from 0.03 mole percent at 161.6K to 0.18 mole percent at 184.3K for n-nonane. The solubility of n-hexane in the mixed solvents methane-ethane and methane-propane were also determined in order to assess the enhancement effect of the solvents ethane and propane. The n-hexane concentration in the mixed solvents were from 0.18 mole percent at 114K to 20.39 mole percent at 154.8K in the mixed solvents of methane and ethane and from 0.65 mole percent at 120.4K to 15.78 mole percent at 153.K in the mixed solvents of methane and propane. An attempt was made to correlate the experimental results through the liquid activity coefficient which was calculated by means of the Redlich-Kwong equation of state with a modified procedure.