Conversion of hydrocarbons

Claim 1

IN A PROCESS FOR CONVERTING HYDROCARBONS WHICH COMPRISES PASSING A RELATIVELY DILUTE SUSPENSION OF CATALYST PARTICLES IN HYDROCARBON VAPORS AS A SUBSTANTIALLY MAIN UPFLOWING STREAM THROUGH THE CENTER OF AN ELONGATED CONVERSION ZONE, SEPARATING SPENT CATALYST PARTICLES FROM CRACKED HYDROCARBON VAPORS LEAVING THE UPPER END OF SAID CONVERSION ZONE, REGENERATING THE SPENT CATALYST PARTICLES, RETURNING REGENERATED CATALYST PARTICLES TO THE LOWER END OF SAID ELONGATED CONVERSION ZONE AND INTRODUCING HYDROCARBON OIL FEED TO BE CONVERSION ZONE AND INTRODUCING TION OF SAID CONVERSION ZONE FOR ADMIXTURE WITH SAID INTRODUCED REGENERATED CATALYST PRTICLES TO FORM SAID RELATIVELY DILUTE SUSPENSION OF CATALYST PARTICLES ABOVE MEMTIONED, THE IMPROVEMENT WHEREBY COCURRENT CONTACTING BETWEEN THE SOLID CATALYST PARTICLES AND VAPOROUS HYDROCARBONS IN THE MAIN UPFLOWING CATALYST SUSPENSION STREAM PASSING UP THROUGH THE CENTER OF SAID ELONGATED CONVERSION ZONE AND SOLID CATALYST PARTICLES PASSING DOWNWARDLY ALONG THE INNER WALL OF SAID ELONGATED CONVERSION ZONE IS OBTAINED WITHOUT SUBDIVIDING THE MAIN UPFLOWING SUSPENSION STREAM INTO A MULTIPLICITY OF STREAMS BY PASSING SAID MAIN SUSPENSION STREAM UPWARDLY THROUGH A SERIES OF SINGLE VENTURI CONSTRICTED ZONES SPACED ONE ABOVE THE OTHER ALONG THE LENGTH OF SAID ELONGATED CONVERSION ZONE TO INCREASE THE VELOCITY OF THE MAIN UPFLOWING CATALYST SUSPENSION STREAM AT SAID CONSTRICTED ZONES AND TO ELIMINATE A LONG BACK-MIXING SOLIDS PATH IN SAID ELONGATED CONVERSION ZONE.