Patent ID: 7172743
Filing Date: 2007-02-06
Classification: B01J,C01C,Y02P

Abstract:
1. A process for producing ammonia comprising reacting a synthesis gas which contains nitrogen and hydrogen on a granular catalyst in at least one reactor at pressures in the range of 50 to 300 bar and temperatures in the range of 100 to 60° C., wherein a product mixture containing NH 3 vapor is removed from the reactor and cooled, whereupon ammonia condenses out and is separated, yielding a circulating gas to which fresh synthesis gas is added, and wherein the circulating gas is returned as synthesis gas back to the reactor, unreacted synthesis gas is passed through a first catalyst bed, which is free of cooling pipes, and then it is sent as a partially reacted synthesis gas having an NH 3 content of 5 to 20 vol % through a heat exchanger, where it functions as heating fluid, wherein partially reacted synthesis gas is passed through at least two additional catalyst beds, which have cooling pipes running through them; unreacted synthesis gas is passed as a cooling gas through the cooling pipes of the additional catalyst beds, and cooling gas heated to 300° C. to 500° C. is passed into the first catalyst bed; the gas flows through the cooling pipes and the additional catalyst beds in co-current, and the cooling gas is first passed through the cooling tubes of a last catalyst bed and then the cooling tubes of a next-to-last catalyst bed.