Regeneration of hydrocarbon synthesis catalysts

Claim 1

IN THE SYNTHESIS OF HYDROCARBONS BY THE CATALYTIC REDUCTION OF CARBON OXIDE WITH HYDROGEN IN A SYNTHESIS REACTION ZONE IN THE PRESENCE OF A SOLID PARTICLE CATALYST UNDER CONDITIONS INCLUDING AN ELEVATED SYNTHESIS TEMPERATURE AT WHICH DESIRED HYDROCARBONS ARE DIRECTLY FORMED WITH THE PRODUCTION OF BY-PRODUCT CARBON DIOXIDE AND THE PROGRESSIVE CONTAMINATION OF THE CATALYST WITH AN OBJECTIONABLE ACCUMULATION OF ELEMENTAL CARBON, THE IMPROVEMENT WHICH COMPRISES LIMITING THE ACCUMULATION OF ELEMENTAL CARBON BY WITHDRAWING FROM THE SYNTHESIS REACTION ZONE CATALYST CONTAMINATED WITH ELEMENTAL CARBON, CONVEYING SAID WITHDRAWN CATALYST SUCCESSIVELY THROUGH A PREHEATING ZONE, A REGENERATION ZONE AND A CATALYST COOLING ZONE, SUBJECTING A DENSE FLUID PHASE OF SAID CATALYST IN SAID REGENERATION ZONE TO CONTACT WITH CARBON DIOXIDE AT A TEMPERATURE MAINTAINED IN THE RANGE ABOVE ABOUT 1000* F., AND IN A CONCENTRATION AT WHICH SAID CARBON DIOXIDE SUBSTANTIALLY CONSUMES ELEMENTAL CARBON IN THE FORMATION OF CARBON MONOXIDE, SEPARATING PRODUCT GASES FROM CONTACT WITH THE CATALYST AT A TEMPERATURE WITHIN SAID RANGE, PREHEATING THE CATALYST IN THE PREHEATING ZONE BY INDIRECT HEAT EXCHANGE WITH THE SAID PRODUCT GASES, PREHEATING SAID CARBON DIOXIDE PRIOR TO INTRODUCTION TO THE REGENERATION ZONE BY DIRECT EXCHANGE WITH HOT CATALYST IN THE CATALYST COOLING ZONE, INTRODUCING MOLECULAR OXYGEN INTO SAID REGENERATION ZONE IN A LIMITED PROPORTION EFFECTIVE TO MAINTAIN THE TEMPERATURE IN SAID ELEVATED RANGE AND RETURNING CATALYST FROM THE COOLING ZONE TO THE REACTION ZONE.