氨氧化装置非稳态瞬间反应的高热效应与催化网失活

High Heat Effect and Deactivation of Catalyst Gauzes Caused by Non-Steady-State Transient Reaction in Ammonia Oxidation Equipment

分析了生产硝酸的氨氧化装置中的基本反应和非稳态反应。在开炉点火初期 ,由于脉冲式供应过量氨气 ,导致氨从催化网低温 (低活性 )区旁路到钯合金捕集网表面 ,在Pd的催化作用下 ,旁路氨与催化网所产生的NOx 发生非稳态瞬间高放热反应 ,导致钯合金捕集网熔化和铂合金催化网粘连失效。我国高压氨氧化装置在反应初期所出现的Pt催化网失效事故 ,就是因非稳态瞬间反应导致Pd捕集网熔化及底层铂合金催化网熔蚀和全部催化网粘连烧结所致。笔者提出了几点改进措施。

Some accidents of deactivation of catalyst gauzes occurred in the initial stage of ammonia oxidation reaction after start-up in ammonia oxidation equipments with high pressure.It was found that all catchment gauzes made of Pd-5Ni alloy and support gauzes made of Fe-20 Cr-5Al alloy were molten completely.Some bottom catalytic gauzes of 30 sheets of Pt-10Rh alloy catalyst gauzes were molten partially by melt of Pd-5Ni alloy and the whole catalyst gauzes were adhered and sintered together.An analysis for the accidents considered that the pulsed excess ammonia feed produced a non-steady-state transient reaction between bypass ammonia and nitrogen oxides NO x on the surface of Pd-5Ni alloy catchment gauzes under strong catalysis of palladium.The non-steady-statetranient reaction is a highly exothermic reaction and resulted in temperature rising exceeding the melting temperature of Pd-5Ni alloy.Some improvement measures were proposed in present paper.