Hydrogen donor diluent cracking process

Claim 1

THE PROCESS OF UPGRADING HEAVY RESIDUAL HYDROCARBONS TO LIGHTER PRODUCTS WHICH COMPRISES BLENDING 0.25 TO 4 PARTS BY VOLUME OF A DILUENT, OBTAINED AS STATED HEREINAFTER, WITH ONE VOLUME OF THE FEED, THERMALLY CRACKING IN A FIRST STAGE THE FEED-DILUENT MIXTURE BY HEATING TO 800 TO 900* F. UNDER A PRESSURE OF NOT MORE THAN 1000 P.S.I.G. AND FOR A RESIDENCE TIME OF 0.25 TO 5 HOURS, SEPARATING LIGHTER PRODUCTS FROM A 700* F.+ BOTTOMS FRACTION OF THE CRACKED MIXTURE, SEPARATING THE BOTTOMS FRACTION INTO A 700 TO 900* F. CUT CONTAINING A MINIMUM AROMATIC CONTENT 40 WT. PERCENT AND A HEAVIER FRACTION, PARTIALLY HYDROGENATING THE 700 TO 900* F. CUT UNDER PRESSURE IN THE PRESENCE OF A HYDROGENATION CATALYST BY ADDING THERETO 200 TO 1000 S.C.F. OF HYDROGEN TO OBTAIN A HYDROGEN/CARBON ATOMIC RATIO IN THE RANGE OF 0.7 TO 1.6, PASSING THE HEAVIER FRACTION FROM THE BOTTOMS TO A SECOND STAGE THERMAL CRACKING ZONE, BLENDING 0.5 TO 4 PARTS BY VOLUME OF DILUENT THEREWITH, AND THERMALLY CRACKING THE MIXTURE UNDER PRESSURE AT A TEMPERATURE OF 850 TO 925* F., AND RECYCLING THE PARTIALLY HYDROGENATED 700 TO 900* F. CUT BOTH CRACKING STAGES TO SERVE AS SAID DILUENT.