Process for the recovery of argon in the production of synthesis gas

Claim 1

IN A PROCESS FOR THE PRODUCTION OF A MIXTURE OF HYDROGEN AND NITROGEN IN PREDETERMINED PROPORTIONS WHEREIN AIR IS SUBJECTED TO LIQUEFACTION AND RECTIFICATION PRODUCING AN OXYGEN-RICH FRACTION CONTAINING ARGON AND A NITROGEN FRACTION SUBSTANTIALLY FREE FROM OXYGEN AND ARGON, A CARBANECEOUS FUEL IS REACTED WITH SAID OXYGENRICH FRACTION IN A GAS GENERATION ZONE UNDER CONDITIONS OF PARTIAL COMBUSTION PRODUCING CARBON MONOXIDE AND HYDROGEN AS THE PRINCIPAL PRODUCTS OF REACTION AND YIELDING A PRODUCT GAS COMPRISING CARBON MONOXIDE, HYDROGEN, ARGON AND METHANE, SAID CARBON MONOXIDE IS CONVERTED TO CARBON DIOXIDE WITH CONCOMITANT PRODUCTION OF HYDROGEN BY REACTION WITH STEAM IN A WATER GAS SHIFT REACTION ZONE, CARBON DIOXIDE AND WATER ARE SEPARATED FROM THE EFFLUENT OF SAID WATER GAS SHIFT REACTION ZONE FORMING A HYDROGEN-RICH GAS STREAM CONTAINING MINOR AMOUNTS OF METHANE, CARBON MONOXIDE, AND ARGON, SAID HYDROGEN-RICH GAS STREAM IS COOLED TO A LOW TEMPERATURE AND CONTACTED WITH SAID NITROGEN FRACTION IN LIQUID PHASE AT AN ELEVATED PRESSURE IN A NITROGEN WASH STEP EFFECTING CONDENSATION OF METHANE, CARBON MONOXIDE AND ARGON FROM SAID GAS STREAM AND FROMING A LIQUID FRACTION COMPRISING NITROGEN, ARGON, CARBON MONOXIDE AND METHANE, THE IMPROVEMENT WHICH COMPRISES PASSING SAID LIQUID FRACTION TO SEPARATE FRACTIONAL DISTALLATION ZONE AT NEAR ATMPOSPHERIC PRESSURE, PASSING GASEOUS NITROGEN AT A PRESSSURE EFFECTIVE TO PRODUCE CONDENSATION THEREOF IN INDIRECT HEAR EXCHANGE WITH LIQUID IN SAID FRACTIONAL DISTILLATION ZONE EFFECTING VAPORIZATION OF SAID LIQUID AND SIMULTANEOUS CONDENSATION OF SAID NITROGEN, SUPPLYING SUBSTANTIALLY PURE LIQUID NITROGEN FROM SAID AIR LIQUEFACTION AND RECTIFICATION STEP TO SAID FRACTIONAL DISTILLATION ZONE AS A REFLUX, EFFECTING SEPARATION BY FRACTIONAL DISTALLATION BETWEEN A METHANE-ARGON LIQUID FRACTION AND A NITROGEN-CARBON MONOXIDE GASEOUS FRACTION, AND PASSING SAID METHANE-ARGON FRACTION TO A SECOND FRACTIONAL DISTALLATION ZONE WHEREIN ARGON SUBSTANTIALLY FREE FROM OTHER CONSTITUENTS IS SEPARATED FROM HIGHER BOILING MATERIALS COMPRISING METHANE.