Catalytic hydrocarbon conversion process

Claim 1

IN EFFECTING THE CATALYTIC DEHYDROGENATION OF A PARTIALLY PREHEATED HYDROCARBON WITH A FINELY DIVIDED SOLID DEHYDROGENATION CATALYST AT A HIGH TEMPERATURE ABOVE ABOUT 1000* F. AND A CONTACT TIME LESS THAN ABOUT 12 SECONDS AND WHEREIN THE REACTANT VAPORS AND FINELY DIVIDED CATALYST ARE CONTACTED WHILE PASSING THE VAPOR WITH THE FINELY DIVIDED CATALYST IN SUSPENSION UP THROUGH A RISER REACTION ZONE, THE IMPROVEMENT WHICH COMPRISES INTRODUCING A HEATED RELATIVELY COARSE SUBSTANTIALLY INERT SOLID HEAT CARRIER MATERIAL NEAR THE BOTTOM OF SAID RISER REACTION ZONE WHEREBY SAID HEAT CARRIER IS CARRIED IN SUSPENSION UP THROUGH SAID RISER REACTION ZONE ALONG WITH THE RELATIVELY MORE FINELY DIVIDED CATALYST, QUENCHING THE MIXTURE LEAVING THE REACTION ZONE AND SEPARATING THE SOLIDS FROM THE GASES, PASSING THE QUENCHED MIXTURE OF CATALYST AND SAID INERT HEAT CARRIER TO A SEPARATION ZONE WHEREIN THE RELATIVELY INERT CARRIER WITHDRAWING SEPARATED INERT HEAT CARRIER FROM NEAR THE BOTTOM OF SAID SEPARATION ZONE AND PASSING IT TO A HEATING ZONE, PASSING HEATED INERT CARRIER TO NEAR THE BOTTOM OF SAID RISER REACTION ZONE AS AFORESAID, AND SEPARATELY PASSING QUENCHED FINELY DIVIDED SOLID CATALYST FROM SAID SEPARATION ZONE TO NEAR THE BOTTOM OF SAID RISER REACTION ZONE, WHEREBY SAID SOLID FINELY DIVIDED CATALYST IS AT A TEMPERATURE BELOW THAT IN THE REACTION ZONE EXCEPT DURING ITS PASSAGE THROUGH SAID RISER REACTION ZONE.