PROCESS FOR THE PREPARATION OF MIDDLE DISTILLATES

摘要

A process for the preparation of one or more hydrocarbon fuel products boiling in the kero/diesel range from a stream of hydrocarbons produced in a Fischer-Tropsch process, in which process synthesis gas is converted into liquid hydrocarbons, at least a part of the hydrocarbons boiling above the kero/diesel range, having the following steps:(1) hydrocracking/hydroisomerizing at least a part of the Fischer-Tropsch hydrocarbons stream at a conversion per pass of at most 80 wt % of the material boiling above 370° C. into material boiling below 370° C.;(2) separating the product stream obtained in step (1) into one or more light fractions boiling below the kero/diesel boiling range, one or more fractions boiling in the kero/diesel boiling range and a heavy fraction boiling above the kero/diesel boiling range;(3) hydrocracking/hydroisomerizing the major part of the heavy fraction obtained in step (2) at a conversion per pass of at most 80 wt % of the material boiling above 370° C. into material boiling below 370° C.;(4) separating the product stream obtained in step (3) into one or more light fractions boiling below the kero/diesel boiling range, one or more fractions boiling in the kero/diesel boiling range and a heavy fraction boiling above the kero/diesel boiling range; and,(5) hydrocracking/hydroisomerizing the major part of the heavy fraction obtained in step (4) in the hydrocracking/hydroisomerizing process described in step (1) and/or step (3), in which process the Fischer-Tropsch hydrocarbons stream comprises at least 35 wt % C30+ (based on total amount of hydrocarbons in the Fischer-Tropsch hydrocarbons stream) and in which stream the weight ratio C60+/C30+ is at least 0.2.