| abstract |
The process for obtaining oils of high viscosity indices, from petroleum distillates or conversion unit effluents, comprises the following steps: a) catalytic hydrotreatment of the feed, in the presence of hydrogen and a non-zeolitic catalyst b) fractionation of at least part of the effluent obtained in step a) or in step d) described below, into an oil residue c) fractionation by thermal diffusion of at least part of the oil residue obtained in step b), in fractions of oils of different compositions and viscosity indices, step b) can be preceded by step d) hydrocracking the effluent obtained in step a), in the presence of hydrogen and a zeolitic catalyst. |