Process for purification of hydrogen

Claim 1

A METHOD FOR SEPARATING HYDROGEN AND METHANE IN A GASEOUS MIXTURE CONTAINING MAINLY HYDROGEN AND METHANE WHICH COMPRISES FEEDING THE GASEOUS MIXTURE INTO AN ABSORPTION ZONE, PASSING THE MIXTURE UPWARDLY COUNTERCURRENT TO A LIQUID C4 TO C5 HYDROCARBON ABSORBENT AT AN ABSORBENT TO FEED RATIO OF BETWEEN ABOUT 0.5 TO 2.0 MOLES OF ABSORBENT PER MOLE OF FEED, SAID ABSORPTION ZONE BEING AT A TEMPERATURE OF -100* TO -200*F. AND UNDER A PRESSURE OF 50 TO 100 P.S.I.A., CORRELATING THE TEMPERATURE, PRESSURE AND ABSORBEMT/FEED RATIO WITHIN THE RANGES SPECIFIED SO THAT THE GASEOUS STREAM WITHDRAWN FROM THE UPPER PART OF SAID ABSORPTION ZONE CONTAINS AT LEAST 99 MOLE PERCENT HYDROGEN WITHDRAWING SAID ABSORBENT CONTAINING METHANE FROM THE BOTTOM OF SAID ABSORPTION ZONE, REDUCING THE PRESSURE ON SAID WITHDRAWN ABSORBENT, FLASHING A MINOR PART OF THE METHANE FROM SAID WITHDRAWN ABSORBENT, AT SUBSTANTIALLY THE TEMPERATURE OF THE ABSORPTION ZONE, SEPARATING A FUEL GAS CONTAINING MOSTLY METHANE FROM THE PARTIALLY DEPRESSURED ABSORBENT, FURTHER REDUCING THE PRESSURE ON THE PARTIALLY DEPRESSURED ABSORBENT LIQUID, DISCHARGING THE DEPRESSURED ABSORBENT LIQUID INTO A FLASHING ZONE, WITHDRAWING A GASEOUS STREAM CONTAINING AT LEAST 99 MOLE PERCENT METHANE OVERHEAD FROM SAID FLASHING ZONE, WITHDRAWING ABSORBENT LIQUID CONTAINING RESIUDAL METHANE FROM SAID FLASHING ZONE, COMPRESSING AND COOLING AND RECYCLING A PORTION OF THE LAST MENTIONED LIQUID TO THE MIDDLE OF THE ABSORPTION ZONE, STRIPPING THE RESIDUAL METHANE FROM THE REMAINDER OF THE SAID ABSORBENT LIQUID AT A TEMPERATURE WHICH IS HIGHER THAN THAT OF SAID ABSORPTION ZONE, COOLING THE STRIPPED ABSORBENT TO -110* TO -200*F. AND RECYCLING THE COOLED, STRIPPED ABSORBENT TO THE UPPER PART OF THE ABSORPTION ZONE.

Claim 2

A METHOD FOR SEPARATING HYDROGEN AND METHANE IN A GASEOUS MIXTURE CONTAINING MAINLY HYDROGEN AND METHANE WHICH COMPRISES FEEDING THE GASEOUS MIXTURE INTO AN ABSORPTION ZONE, PASSING THE MIXTURE UPWARDLY COUNTERCURRENT TO A LIQUID C4 TO C5 HYDROCARBON ABSORBENT AT AN ABSORBENT TO FEED RATIO OF BETWEEN ABOUT 0.5 TO 2.0 MOLES OF ABSORBENT PER MOLE OF FEED, SAID ABSORPTION ZONE BEING AT A TEMPERATURE OF -100* TO -200*F. AND UNDER A PRESSURE OF 50 TO 100 P.S.I.A., CORRELATING THE TEMPERATURE, PRESSURE AND ABSORBEMT/FEED RATIO WITHIN THE RANGES SPECIFIED SO THAT THE GASEOUS STREAM WITHDRAWN FROM THE UPPER PART OF SAID ABSORPTION ZONE CONTAINS AT LEAST 99 MOLE PERCENT HYDROGEN WITHDRAWING SAID ABSORBENT CONTAINING METHANE FROM THE BOTTOM OF SAID ABSORPTION ZONE, REDUCING THE PRESSURE ON SAID WITHDRAWN ABSORBENT, FLASHING A MINOR PART OF THE METHANE FROM SAID WITHDRAWN ABSORBENT, AT SUBSTANTIALLY THE TEMPERATURE OF THE ABSORPTION ZONE, SEPARATING A FUEL GAS CONTAINING MOSTLY METHANE FROM THE PARTIALLY DEPRESSURED ABSORBENT, FURTHER REDUCING THE PRESSURE ON THE PARTIALLY DEPRESSURED ABSORBENT LIQUID, DISCHARGING THE DEPRESSURED ABSORBENT LIQUID INTO A FLASHING ZONE, WITHDRAWING A GASEOUS STREAM CONTAINING AT LEAST 99 MOLE PERCENT METHANE OVERHEAD FROM SAID FLASHING ZONE, WITHDRAWING ABSORBENT LIQUID CONTAINING RESIUDAL METHANE FROM SAID FLASHING ZONE, COMPRESSING AND COOLING AND RECYCLING A PORTION OF THE LAST MENTIONED LIQUID TO THE MIDDLE OF THE ABSORPTION ZONE, STRIPPING THE RESIDUAL METHANE FROM THE REMAINDER OF THE SAID ABSORBENT LIQUID AT A TEMPERATURE WHICH IS HIGHER THAN THAT OF SAID ABSORPTION ZONE, COOLING THE STRIPPED ABSORBENT TO -110* TO -200*F. AND RECYCLING THE COOLED, STRIPPED ABSORBENT TO THE UPPER PART OF THE ABSORPTION ZONE.