Liquid–Liquid Equilibria (<i>T</i>–<i>x</i>–<i>x</i>) Data for {<i>n</i>-Octane/<i>n</i>-Hexadecane + Thiophene + NMP/Sulfolane} at <i>T</i> = 308.15 K and <i>P</i> = 0.1 MPa

Abstract

Crude oil-derived fuels containing natural sulfur contaminants contribute significantly to the energy mix. Therefore, in addressing cleaner production sustainable goals, sulfur must be removed as these sulfur contaminants reduce the quality of the fuel. In this work, N-methyl-2-pyrrolidone (NMP) and sulfolane were investigated for their capability to remove thiophene from model fuels, such as n-octane and n-hexadecane. Ternary liquid–liquid equilibria (LLE) data were measured for four ternary systems, namely, n-octane/n-hexadecane + thiophene + NMP/sulfolane, at 308.15 K and 0.1 MPa. The NRTL model was used to correlate the experimental data. The maximum likelihood method was used to minimize the objective function. The regressed binary interaction parameters were consistent with measured data with an average root-mean-square deviation (RMSD) of 0.00024. The binary interaction parameters from the data regression were verified by assessing the topology of the model-predicted Gibbs energy of mixing for the studied mixtures. The systems generally exhibited the type 1 LLE behavior except for the system of n-hexadecane + thiophene + sulfolane, which exhibited type 2 behavior. Results indicate that sulfolane exhibits increased selectivity to thiophene from n-octane and n-hexadecane than NMP.