Nitrogen mon:oxide removal from oxygen-free gas - esp. ammonia synthesis gas by adsorption on molecular sieve zeolite with transition metal cations

摘要

Removal of NO from O2-free gas is effected by contact with mol. sieve zeolites in which the cations consist wholly or partly of transition metal ions, pref. Cu2+, Ni2+, Ag+, Cr3+, Co2+, and/or Fe3+. The process is useful for removing harmful traces of NO, esp. from NH3 synthesis gas. Up to 75 Nm3 gas with a NO content of 10 ppm can be purified with 1 kg zeolite to a NO content of 0.03 ppm, using high throughputs of up to 3 Nm3/h. Pref. the zeolite is a type A zeolite, faujasite with a SiO2/Al2O3 molar ratio of 2-6, type L zeolite, mordenite and/or erionite and contains =1 (=2) wt.% transition metal. Desorption may be effected with N2 at 150-350 degrees C.