Process for the hydrogenation of an unsaturated hydrocarbon

Claim 1

AN IMPROVED PROCESS FOR THE HYDROGENATION OF A CHARGE STOCK COMPRISING THE DEBUTANIZED TO 400*F. FRACTION FROM THE THERMAL CRACKING OF AT LEAST ONE LOW BOILING HYDROCARBON HAVING BETWEEN 2 AND 4 CARBON ATOMS PER MOLECULE TO PRODUCE ETHYLENE WHICH COMPRISES: (1) PREHEATING SAID CHARGE STOCK TO A TEMPERATURE LESS THAN 260*F.; (2) ADMIXING A PREHEATED REFRACTORY MATERIAL BOILING BETWEEN 400*F. AND 850*F. AT ATMOSPHERIC PRESSURE WITH SAID CHARGE STOCK; (3) PASSING SAID ADMIXTURE DOWNFLOW OVER A HYDROGENATION CATALYST SELECTED FROM THE GROUP CONSISTING OF THE METALS FROM GROUP VI AND THE IRON GROUP METALS FROM GROUP VIII OF THE PERIODIC TABLE, THEIR OXIDES AND SULFIDES, SUPPORTED ON A NON-CRACKING BASE IN A HYDROGENATION ZONE UNDER HYDROGENATION CONDITIONS INCLUDING A TEMPERATURE BETWEEN 350*F. AND 750*F.; (4) SAID REFRACTORY MATERIAL BEING ADMIXED WITH SAID CHARGE STOCK JUST PRIOR TO PASSING SAID ADMIXTURE DOWNFLOW OVER SAID HYDROGENATION CATALYST; AND (5) WHEREIN THE VOLUME RATIO OF SAID REFRACTORY MATERIAL TO SAID CHARGE STOCK IS BETWEEN 0.2:1 AND 40:1 AND WHEREIN THE REFRACTORY MATERIAL IS PREHEATED TO A TEMPERATURE BETWEEN 500*F. AND 780*F., THE AMOUNT AND TEMPERATURE OF SAID REFRACTORY MATERIAL BEING SUFFICIENT TO INCREASE THE TEMPERATURE OF SAID ADMIXTURE TO BETWEEN 300*F. AND 500*F. AND TO MAINTAIN A CONTINUOUSLY MOVING LIQUID FILM ON THE HYDROGENATION CATALYST TO REDUCE POLYMER FORMATION IN SAID HYDROGENATION ZONE.