Conversion of asphaltic materials

Claim 1

A PROCESS FOR HYDROCRACKING AN ESSENTAILLY ASPHALTIC HYDROCARBON FEED STOCK CONTAINING LESS THAN ABOUT 15% OF MATERIALS BOILING BELOW 1050* F., SAID ASPHALTIC FEED STOCK HAVING THE NAPHTHA INSOLUBLES CONTENT IN EXCESS OF ABOUT 5 WEIGHT PERCENT, SAID PROCESS COMPRISING THE STEPS OF CONTACTING THE SAID FEED STOCK WITH A FIXED BED OF A POROUS SOLID HYDROCRACKING CATALYST IN THE PRESENCE OF FROM ABOUT 500 TO 6000 CUBIC FEET OF HYDROGEN PER BARREL OF FEED STOCK IN A PLURALITY OF REACTION ZONES OPERATED IN SERIES AT SUCCESSIVELY HIGHER TEMPERATURES, AT A PRESSURE WITHIN THE RANGE OF ABOUT 200 TO 900 P.S.I.G., AND AT A SPACE VELOCITY WITH THE RANGE OF ABOUT 0.2K TO ABOUT 5 VOLUMES OF SAID FEED STOCK PER VOLUME OF CATALYST PER HOUR, SAID TEMPERATURES BEING WITHIN THE RANGE OF ABOUT 650* TO 825* F., THE TEMPERATURE IN THE FIRST OF SAID ZONES BEING SUFFICIENTLY HIGH TO CAUSE SUBSTANTIAL HYDROCRACKING BUT BELOW THE INCIPIENT COKING TEMPERATURE OF THE ASPHALT AND BEING WITHIN THE RANGE OF ABOUT 650* TO 730 * F. AND THE TEMPERATURE IN EACH SUCCEEDING ZONE BEING AT LEAST 5* F. HIGHER THAN THAT IN THE IMMEDIATELY PRECEDING