The reaction of nitric oxides with methane, ethane, propane and n-butane was investigated in the heating temperature range 900-1100°C using a tubular flow reactor.
In one-stage reaction, the conversion of NO
x was accelerated at air ratio below 1.0 and the per-cent of conversion of NO
x to HCN increased with the decrease of air ratio. The intermediate products were oxidized by adding secondary oxygen and by reheating. They were oxidized completely at reheating temperature above 1100°C and at residual oxygen concentration above 0.5‰. It was sug-gested that both NO regeneration and N
2 production were taking place on oxidation of HCN. The ratio of NO regeneration increased at higher oxygen and lower NO
x concentration, and the percent of NO
x reduction in two-stage reaction decreased. Propane and n-butane showed higher percent of NO
x conversion and reduction than methane and ethane at high primary air ratio. The percent of NO
x con-version increased with the increase of concentration of hydrocarbon. The maximum percent of NO
x reduction was obtained at concentrations of propane 0.33-0.67‰ or n-butane 0.25-0.5‰. The ef-fect of first-stage temperature, gas flow rate, CO
2, SO
2 and H
2O was also investigated.
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