HIGH PRESSURE HYDROCRACKING OF VACUUM GAS OIL TO MIDDLE DISTILLATES.

This investigation was aimed at maximizing the yield of middle distillate (140-270 degree C boiling range) by hydrocracking a vacuum gas oil (365-450 degree C boiling range) fraction from an Indian Refinery at high hydrogen pressure and temperature. A zeolite catalyst-base exchanged with 4. 5% Ni was chosen for the reaction. A high pressure batch reactor with a rocking arrangement was used for the study. No pretreatment of the feed stock for sulphur removal applied as the total sulphur in the feed was less than 2%. The process variables studied for the maximum yield of the middle distillate were temperature 300-450 degree C, pressure 100-200 bar and residence period 1-3 h at the feed to catalyst ratio of 9. 3 (wt/ wt). The optimum conditions for the maximum yield of 36% middle distillate of the product were: temperature 400 degree C, pressure 34. 5 bar (initially) and residence period 2 h.