Catalytic production of ammonia, especially for direct conversion into urea, using nitrogen-hydrogen starting gas mixture obtained from natural gas by autothermal reforming and catalytic conversion

摘要

Catalytic production of ammonia from nitrogen-hydrogen gas mixture involves forming synthesis gas from natural gas and oxygen-rich gas in an autothermal reactor, catalytic conversion of CO into H2, removal of CO, CO2 and methane and supplying the obtained nN2-H2 mixture to catalytic synthesis of NH3. Catalytic production of ammonia from a nitrogen-hydrogen gas mixture involves: (a) supplying natural gas and oxygen-rich gas to an autothermal reformer at 900-1200 deg C and 40-100 bars in presence of a cracking catalyst, to give crude synthesis gas (I) containing (by volume, on a dry basis) 55-75% H2, 15-30% carbon monoxide and 15-30% carbon dioxide, the H2 to CO volume ratio being 1.6-4; (b) withdrawing (I) from the reformer, cooling and subjecting (I) to catalytic conversion of CO into H2, giving converted synthesis gas (II) containing (by volume, on a dry basis) at least 55% H2 and at most 8% CO; (c) subjecting (II) to multi-stage purification to remove CO2, CO and methane; and (d) supplying the obtained nN2-H2 mixture to the catalytic synthesis of NH3.