Process for separating recycle hydrogen from entrained condensed gases in hydrodesulfurization process

Claim 1

IN A PROCESS FOR THE DESULFURIZATION OF HYDROCARBONS IN THE PRESENCE OF HYDROGEN IN WHICH THE DESULFURIZED PRODUCT AFTER PRELIMINARY HEAT EXCHANGE COMPRISES A LIQUID-VAPOR HYDROCARBON MIXTURE CONTAINING HYDROGEN, IN WHICH THE HYDROGEN IS SEPARATED FROM THE HYDROCARBON MIXTURE AT A LOW TEMPERATURE, SAID MIXTURE BEING INITIALLY AT AN ELEVATED TEMPERATURE AND PRESSURE, AND IN WHICH THE MIXTURE IS FURTHER TREATED IN A FRACTIONATING ZONE FOR THE PURPOSE OF SEPARATING IT INTO AT LEAST TWO FRACTIONS, THE IMPROVEMENT WHICH COMPRISES INTRODUCING THE LIQUID-VAPOR HYDROCARBON MIXTURE CONTAINING HYDROGEN TO THE FIRST OF A SERIES OF AT LEAST TWO ZONES, REMOVING VAPOR FROM EACH OF THE ZONES AND PASSING IT TO THE SUCCEEDING ZONE IN THE SERIES, INTRODUCING A LIQUID ABSORBENT MATERIAL OBTAINED IN A MANNER HEREINAFTER DESCRIBED INTO AT LEAST ONE OF THE SERIES OF ZONES, PROVIDING SUFFICIENT COOLING BEFORE AT LEAST THE ZONES FREE OF ABSORBENT TO CONDENSE A PART OF THE VAPOR, REMOVING THE LIQUID FROM EACH ZONE OF THE SERIES, PASSING THE LIQUID FROM ALL BUT THE LAST ZONE TO A FRACTIONATING ZONE MAINTAINED AT A PRESSURE BELOW THE PRESSURE IN THE LAST ZONE OF THE SERIES WHEREIN IT IS SEPARATED INTO AN OVERHEAD VAPOR FRACTION AND AT LEAST ONE HEAVIER FRACTION, SUBJECTING THE OVERHEAD FRACTION TO COOLING WHEREBY AT LEAST A PORTION OF THIS MATERIAL IS CONDENSED, INTRODUCING A PORTION OF THE CONDENSED MATERIAL TO A ZONE NOT IN THE SERIES WHICH IS MAINTAINED AT A PRESSURE INTERMEDIATE BETWEEN THE PRESSURE IN THE LAST ZONE OF THE SERIES AND THE FRACTIONATING ZONE, PASSING CONDENSED MATERIAL WHICH ACTS AS AN ABSORBENT FROM THE ZONE OF THE INTERMEDIATE PRESSURE INTO AT LEAST ONE OF THE SERIES OF ZONES AS PREVIOUSLY DESCRIBED WHEREBY THE CONCENTRATION OF LIGHT HYDROCARBONS IN THE VAPOR PHASE OF SAID ZONE IS DECREASED, PASSING THE LIQUID FROM THE LAST OF THE SERIES OF ZONES TO THE ZONE OF INTERMEDIATE PRESSURE AND REMOVING A VAPOR RICH IN HYDROGEN FROM THE LAST IN THE SERIES OF ZONES.