(267d) Novel High Active Catalyst Innovation and Low-Energy Consumption Process Technology for Ammonia Synthesis

Although catalytic ammonia synthesis technology has been matured comparatively, it still has tremendous potential for energy-saving. Further decrease of energy consumption depends mainly on high active catalyst innovation and its process for ammonia synthesis. This paper reported a ZA-5 catalyst with wüstite as precursor. It recently is a performance update of the most successful catalyst innovation for the ammonia synthesis. ZA-5 catalyst has very high activity at low temperature and pressure, so as to be competitive with costly Ru/AC catalyst. The relations between pressure, power and catalytic activity in synthesis loop were investigated. Based on the above analysis, it is proposed that new idea that the decrease in net value of ammonia resulting from the decrease in pressure can be compensated by the high activity of the novel catalyst, and a newly low-energy consumption process technology of ammonia synthesis based on high efficient ZA-5 catalyst was proposed according to optimized design. The results of optimized design indicated that, with the decrease of the pressure of synthesis loop the ammonia net value, concentration of inert gas in vent gas and ammonia condensation temperature can basically remain unchanged, the power of cycle compressor and refrigeration compressor is the same with it in high pressure, but the total power decrease mainly because of the power of the syngas compressor decreased with the decreasing pressure. And efficiency of energy-saving achieves 12.34 % and 18.31 %, saving energy achieves 1.50 GJ.t^-1 and 2.23 GJ.t^-1 or 51.34 kgce.t^-1 and 76.16 kgce.t^-1 when pressure decreasing from 30 MPa to 15 MPa and 10MPa in synthesis loop for the ammonia plant with capacity of 200 kt.year^-1, respectively.