Production of ammonia

Claim 1

IN A PROCESS WHEREIN NATURAL GAS IS REFORMED BY REACTION WITH STEAM TO PRODUCE A GAS CONTAINING HYDROGEN AND CARBON MONOXIDE AND RESIDUAL QUANTITIES OF METHANE, AIR IS ADMIXED WITH SAID GAS AND SUBJECTED TO A SECOND REACTION CAUSING REMOVAL OF OXYGEN PRESENT IN SAID AIR BY COMBUSTION REACTION, RESULTING GAS IN FREED OF CARBON MONOXIDE AND CARBON DIOXIDE, THUS PURIFIED GAS RICH IN HYDROGEN AND NITROGEN BUT STILL CONTAINING A MODICUM OF METHANE IS COMPRESSED AND CONTACTED WITH AN AMMONIA SYNTHESIS CATALYST AT SYNTHESIS CONDITIONS CAUSING FORMATION OF AMMONIA BY REACTION OF HYDROGEN WITH NITROGEN, AMMONIA IS RECOVERED AS PRODUCT, CYCLE GAS CONTAINING UNREACTED HYDROGEN AND NITROGEN AND HAVING METHANE CONCENTRACTED THEREIN BY VIRTUE OF ITS INERTNESS IN THE AMMONIA SYNTHESIS REACTION IS RECYCLED TO THE AMMONIA SYNTHESIS REACTION, AND A PORTION OF SAID CYCLE GAS IS WITHDRAWN FROM THE AMMONIA SYNTHESIS SYSTEM TO AVOID PYRAMIDING OF METHANE THEREIN, THE IMPROVEMENT WHEREBY HYDROGEN AND NITROGEN IN SAID WITHDRAWN GAS ARE UTILIZED REDUCING THE AMOUNT OF AIR NECESSARY TO BE ADDED TO SAID SECOND REACTION AND METHANE THEREIN IS EFFECTIVELY REMOVED FROM THE PROCESS, WHICH COMPRISES ADMIXING AIR WITH SAID WITHDRAWN PORTION OF GAS, SUBJECTING THE RESULTING ADMIXTURE TO COMBUSTION CONDITIONS CAUSING REACTION OF OXYGEN IN SAID AIR WITH METHANE AND HYDROGEN IN SAID GAS TO PRODUCE A RESULTING METHANE-POOR, HYDROGEN-POOR, NITROGENRICH GAS, AND INTRODUCING SAME INTO ADMIXTURE WITH GAS OBTAINED FROM SAID SECOND REACTION WHEREBY THE NITROGEN CONTENT OF THE GAS RESULTING FROM THE LAST SAID COMBUSTION IS REINTRODUCED TO THE AMMONIA SYNTHESIS REACTION.