Evaluation of hydroisomerization products as lube base oils based on carbon number distribution and hydrocarbon type analysis

A gas oil fraction of a deasphalted vacuum residue, after hydrotreatment, was hydroisomerized in a flow fixed-bed reactor over a commercial catalyst. Liquid products were distilled, on separate occasions, by a simple method for preliminary study and by true boiling point distillation for detailed investigation. Carbon number distributions and hydrocarbon types for various cuts were performed by high temperature GC-MS. It was found that for the light fractions, isoparaffins increased while monocycloalkanes decreased as the boiling point increased. As for the heavy fractions, with the rise in boiling point, each cut had a wider carbon number distribution. Concentrations of monocycloalkanes and isoparaffins in the lube base oil cut had a significant impact on its viscosity index and pour point.