Olefin production process

Claim 1

THE PROCESS FOR THERMALLY TREATING A HEAVY HYDROCARBON CHARGE TO SIMULTANEOUSLY PRODUCE COKE AND PREDOMINANT YIELDS OF GASEOUS UNSATURATED HYDROCARBONS HAVING LESS THAN FOUR CARBON ATOMS TO THE MOLECULE: WHICH COMPRISES PREHEATING SAID HYDROCARBON CHARGE TO A TEMPERATURE BELOW ITS CRACKING TEMPERATURE AND IN THE ORDER OF ABOUT 700 TO 800*F., INTRODUCING SAID PREHEATED CHARGE INTO A FLASH ZONE WHEREIN LIGHT ENDS ARE FLSHED FROM SAID PREHEATED CHARGE; WITHDRAWING AS A BOTTOM STREAM FROM SAID FLASH ZONE NORMALLY LIQUID HYDROCARBONS HAVING A BOILING RANGE OF HEAVY FUEL OIL; HEATING SAID BOTOMS TO ABOUT 900 TO 950*F. AND INTRODUCING SAID HEATED BOTTOMS, A PORTION OF WHICH IS IN THE VAPOR PHASE, INTO A COKING ZONE; MAINTAINING THE TEMPERATURE AND PRESSURE IN SAID COKING ZONE SO AS TO MILDLY CRACK THE LIQUID PORTION OF SAID HEATED BOTTOMS WHEREBY THE UNVAPORIZED PORTION OF SAID BOTTOMS IS ULTIMATELY CONVERTED TO DRY COKE AND ADDITIONAL VAPORS; WITHDRAWING OVERHEAD VAPORS FROM SAID COKING ZONE AND INTRODUCING SAID VAPORS TO SAID FLASH ZONE AT A POINT BELOW THE POINT OF INTRODUCTION OF SAID PREHEATED CHARGE WHEREBY, DURING CONTACT WITH SAID PREHEATED CHARGE, SAID LIGHT ENDS ARE FLASHED FROM SAID CHARGE AND THE HEAVIEST LIQUID CONSTITUENTS OF SAID VAPORS HAVING A BOILING RANGE OF FUEL OIL ARE CONDENSED; WITHDRAWING NONCONDENSED VAPORS INCLUDING GAS, GASELINE AND GAS OIL AND SAID LIGHT ENDS FROM THE UPPER PART OF SAID FLASH ZONE; MIXING SAID NONCONDENSED VAPORS AND LIGHT ENDS WITH SUPERHEATED STEAM AND PASSING THE MIXTURE THROUGH A CRACKING ZONE IN DIRECT HEAT EXCHANGE CONTACT WITH A HOT THERMALLY REGENERATED REFRACTORY MASS CONTAINED THEREIN, MAINTAINING SAID MIXTURE IN SAID CRACKING ZONE FOR A PERIOD OF FROM A FRACTION OF A SECOND TO SEVERAL SECONDS; MAINTAINING THE TEMPERATURE OF THE REFRACTORY MATERIAL IN SAID CRACKING ZONE IN THE RANGE FROM 1500 TO 2200*F. THEREBY PRODUCING AN EFFLUENT CONTAINING A HIGH PERCENTAGE OF UNSATURATED HYDROCARBONS HAVING LESS THAN FOUR CARBONS ATOMS TO THE MOLECULE; QUENCHING SAID EFFLUENT; SEPARATING AS PRODUCT SAID UNSATURATED HYDROCARBONS FROM SAID QUENCHED EFFLUENT; AND WITHDRAWING DRY COKE FROM SAID COKING ZONE AS PRODUCT.