Starting up procedure in the hydrocaracking of hydrocarbons

Claim 1

A START-UP PROCEDURE FOR USE IN A HYDROCRACKING PROCESS, WHICH PROCESS COMPRISES HYDROCRACKING A HYDROCARBON FEED WHICH IS SUBSTANTIALLY COMPOSED OF HYDROCARBONS HAVING A BOILING POINT BELOW ABOUT 800*F., WHICH HAS A NITROGEN CONTENT BELOW ABOUT 25 P.P.M. AND WHICH IS SUBSTANTIALLY FREE OF ASPHALTIC MATERIALS UTILIZING A CATALYST COMPRISING ESSENTIALLY NICKEL-TUNGSTEN SULFIDE COMPOSITED WITH A SILICEOUS CARRIER HAVING A HIGH ACTIVITY INDEX, THE NICKEL-TUNGSTEN COMPONENTS BEING SUBSTANTIALLY IN SULFIDED FORM DURING THE MAJOR CONVERSION PORTION OF THE HYDROCRACKING PROCESS, SAID START-UP PROCEDURE COMPRISING INITIALLY CONTACTING THE HYDROCARBON FEED WITH HYDROGEN IN THE PRESENCE OF A CATALYST CONSISTING OF NICKEL-TUNGSTEN COMPOSITED WITH A SILICEOUS CARRIER WHILE THE NICKEL AND TUNGSTEN COMPONENTS ARE SUBSTANTIALLY UNSULFIDED, AT A HYDROGEN PARTIAL PRESSURE OF BETWEEN ABOUT 400 AND 3000 P.S.I., AT AN INITIAL TEMPERATURE BELOW ABOUT 500*F. AND WHILE ADDING EXTRANEOUS SULFUR TO THE FEED IN AN AMOUNT IN THE RANGE OF ABOUT 0.1 TO ABOUT 2.0 PERCENT BY WEIGHT BASED UPON THE TOTAL LIQUID HYDROCARBON FEED, INCREASING THE TEMPERATURE UNTIL THE DESIRED CONVERSION IS OBTAINED, REDUCING THE AMOUNT OF EXTRANEOUS SULFUR BEING ADDED TO THE FEED AFTER THE NICKELTUNGSTEN COMPONENTS HAVE BEEN SUBSTANTIALLY CONVERTED INTO THE SULFIDED FORM TO AN AMOUNT IN THE RANGE OF ABOUT 40 P.P.M. TO ABOUT 1.5 PERCENT BY WEIGHT BASED UPON THE TOTAL LIQUID HYDROCARBON FEED, MAINTAINING THE CONVERSION BY INCREASING THE TEMPERATURE AND CONTINUING THE INTRODUCTION OF SULFUR.