Process for the production of ammonia synthesis feed gas

Claim 1

A PROCESS FOR THE PRODUCTION OF A MIXTURE OF HYDROGEN AND NITROGEN IN PREDETERMINED PROPORTIONS COMPRISING SUBJECTING AIR TO LIQUEFACTION AND RECTIFICATION PRODUCING AN OXYGEN-RICH FRACTION CONTAINING ARGON AND A NITROGEN FRACTION SUBSTANTIALLY FREE FROM OXYGEN AND ARGON; REACTING A CARBONACEOUS FUEL WITH SAID OXYGEN-RICH 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; CONVERTING SAID CARBON MONOXIDE TO CARBON DIOXIDE WITH CONCOMITANT PRODUCTION OF HYDROGEN BY REACTION WITH STEAM IN A WATER GAS SHIFT REACTION ZONE; SEPARATING CARBON DIOXIDE AND WATER FROM THE EFFLUENT OF SAID WATER GAS SHIFT REACTION ZONE FORMING A HYDROGEN-RICH GAS STREAM CONTAINING MINOR AMOUNTS OF METHANE, NITROGEN, AND ARGON; COOLING SAID HYDROGEN-RICH GAS STREAM TO A TEMPERATURE BELOW THE FREEZING POINT OF METHANE AND CONTACTING SAID GAS STREAM WITH SAID NITROGEN FRACTION IN LIQUID PHASE CONDENSING METHANE AND ARGON FROM SAID GAS STREAM; SEPARATING A GASEOUS MIXTURE OF NITROGEN AND HYDROGEN SUBSTANTIALLY COMPLETELY FREE FROM OTHER CONSTITUENTS FROM THE LIQUID FRACTION COMPRISING NITROGEN, ARGON, AND METHANE; AND VAPORIZING AND RETURNING A SUFFICIENT AMOUNT OF SAID LIQUID FRACTION TO SAID GAS GENERATION ZONE TO MAINTAIN THE CONCENTRATION OF ARGON IN SAID HYDROGENRICH GAS STREAM AT LEAST EQUAL TO THE CONCENTRATION REQUIRED TO PREVENT FREEZING OF METHANE AND EFFECTIVE TO SATISFY THE FOLLOWING FORMULA: