Hydrogenation of hydrocarbons with a fixed catalyst bed, and the recycling of hydrogen at spaced points for temperature control

Claim 1

PROCESS FOR HYDROGENATING CONSTITUENTS OF HYDROCARBON MIXTURES WHICH COMPRISES INTRODUCING A HYDROCARBON MIXTURE IN LIQUID PHASE INTO A BED OF GRANULAR SOLID HYDROGENATION CATALYST, PASSING THE HYDROCARBON MIXTURE DOWNWARDLY IN LIQUID PHASE THROUGH THE BED, PASSING HYDROGEN-CONTAINING GASES INTO THE BED AT A LEVEL ABOVE THE LOWER END THEREOF, WHEREBY THE HYDROCARBON MIXTURE IS COOLED BY SAID GASES, MAINTAINING A RELATIVELY HIGH TEMPERATURE IN THE HYDROCARBON MIXTURE IN AN UPPER ZONE ABOVE SAID LEVEL, PASSING THE HYDROGEN-CONTAINING GASES UPWARDLY THROUGH THE UPPER ZONE COUNTERCURRENT TO THE LIQUID HYDROCARBON MIXTURE WHEREBY HYDROGENATION OF CONSTITUENTS OF THE HYDROCARBON MIXTURE TAKES PLACE, MAINTAINING A LOWERED TEMPERATURE IN A LOWER ZONE BENEATH SAID LEVEL, WHEREBY DECOMPOSITION REACTIONS ARE REDUCED IN SAID LOWER ZONE, AND PERIODICALLY LOWERING THE LEVEL OF THE INTRODUCTION OF HYDROGEN-CONTAINING GASES INTO THE BED, THEREBY TO INCREASE THE SIZE OF THE UPPER ZONE AND TO DECREASE THE SIZE OF THE LOWER ZONE.