Catalyst reactivation in the production of hydrogen for ammonia synthesis

Claim 1

IN AN AMMONIA SYNTHESIS PROCESS WHEREIN A MIXTURE OF STEAM AND METHANE IS PASSED OVER REDUCED NICKEL OXIDE CATALYST AT ELEVATED TEMPERATURE TO FORM A PRIMARY EFFLUENT CONTAINING STEAM AND GAS INCLUDING HYDROGEN, CARBON OXIDES AND METHANE, SAID PRIMARY EFFLUENT IS MIXED WITH AIR AND MORE STEAM AND AGAIN CONTACTED WITH REDUCED NICKEL OXIDE CATALYST AT A STILL HIGHER TEMPERATURE TO FORM A SECONDARY EFFLUENT CONTAINING HYDROGEN, NITROGEN, CARBON OXIDES, STEAM AND METHANE, SAID SECONDARY EFFLUENT IS CONTACTED WITH IRON OXIDE CATALYST TO REACT STEAM AND CARBON MONOXIDE TO FORM ADDITIONAL HYDROGEN AND CARBON DIOXIDE, THE THUS FORMED SYNTHESIS GAS IS TREATED TO REMOVE CARBON OXIDES, AND PASSED TO AN AMMONIA SYNTHESIS REACTOR, AMMONIA IS CONDENSED FROM THE REACTOR EFFLUENT AND THE UNCONDENSED GASES ARE RECIRCULATED TO SAID REACTOR, A PORTION OF SAID UNCONDENSED GASES BEING PURGED TO PREVENT INERTS SUCH AS METHANE AND ARGON FROM BUILDING UP IN THE SYSTEM, THE IMPROVED METHOD OF REACTIVATING SAID FIRST MENTIONED REDUCED NICKEL OXIDE CATALYST WHICH COMPRISES INCREASING THE STEAM FEED IN SAID MIXTURE IN MULTIPLE STEPS AT ABOUT 1 HOUR INTERVALS SO THAT THE STEAM/GAS VOLUME RATIO IN SAID PRIMARY EFFLUENT INCREASES FROM AN ORIGINAL VALUE IN THE RANGE OF ABOUT 0.50 TO 0.60 IN INCREMENTS OF ABOUT 0.01 TO 0.015 TO AN ULTIMATE VALUE IN THE RANGE OF ABOUT 0.60 TO 0.70, MAINTAINING SAID RATIO AT SAID ULTIMATE VALUE FOR ABOUT 2 TO 16 HOURS AND THEN RETURNING SAID RATIO TO SAID ORIGINAL VALUE IN ONE STEP.