| 摘要 |
<p>Outlet gas is freed from N2O3, N2O4, NO2 and N2O5 by adsorption with alkaline reagents, pref. milk of lime, is (a) contacted wtih pyrite (FeS2) in a way such that the gas is led downwards through the pyrite layer at a rate such that =0.25 mole NO/hr. are charged per 1 sq.m. pyrite particle surface, and main part NO is reduced to N2. During contact of the gas with pyrite, the pyrite layer is scrubbed with water to remove the pyrite oxidation products formed, such as Fe2(SO4)3 and H2SO4. The residual small amount of N oxide in gas is reduced by (b) contact with a gas containing CO in an amount sufficient to reduce NO to N2. Pref. pyrite has particle size >=2, more pref. 3-10, mm. Pref. in water-scrubbing step, water is charged at 0.3-6 l./mole NO in gas to be purified. Pref. CO-containing gas used is producer gas, and contact time in (b) is 10-15 secs.</p> |
