Solubility of carbon monoxide in bio-oil compounds

Abstract

The solubility of carbon monoxide is measured in four different bio-oil compounds (furan, diacetyl, 2-methylfuran, and trans-crotonaldehyde) at temperatures (273.15, 283.15, 298.15, and 323.15K) and pressures up to 8MPa using a static-analytical VLE measurement method. The equipment was validated by measuring the solubility of CO2 in methanol at 298.15K and pressures (P=2.9–5.7MPa). The results were compared with the abundantly available literature values. PC-SAFT, Polar PC-SAFT (PPC-SAFT), and Cubic (SRK, PR) EoS, part of commercial process simulator Aspen Plus V. 8.6, are used here for modelling purpose. The pure component parameters needed for PC-SAFT and PPC-SAFT EoS models, are regressed using the experimental liquid density and vapour pressure data of the pure components. It was observed that furan, 2-methylfuran and diacetyl, having weak dipole moments (μ<1.0D), could be modelled reasonably well without the addition of polar contribution using conventional PC-SAFT, while it is recommended to use PPC-SAFT for the description of a polar compound like trans-crotonaldehyde (μ∼3.67D).It was observed that SRK and PR EoS have similar predictive ability in comparison to PC-SAFT for a mixture of CO with weakly polar compounds in this study. A comparison between the performances of EoS models was made in two ways: first by setting the binary interaction parameter kij to zero, and second by adjusting a temperature-dependent binary interaction parameter (kij). All the models perform with comparable accuracy with adjusted binary interaction parameters. However, due to the large differences between the chemical and physical properties of the compounds in this study, it is challenging to make a general statement on which is the best model.