| 摘要 |
PURPOSE:To reduce NOx surely at a low cost by specifying O2 and CO concns. of a mixed gas of blast furnace (or converter) exhaust gas with smelting exhaust gas which contains CO as a reducing agent. CONSTITUTION:While being sent through a flue 2 to a denitrating catalyst layer 10, exhaust combustion gas from its originating source 1 is mixed with smelting exhaust gas, which is added through a nozzle 8 and contains CO as a reducing agent. An O2-concn. analyzer 3, a combustion control unit 4, a flow meter 5b and a flow control unit 5 for exhaust smelting gas, and a flow control valve 5a are adjusted respectively so as to maintain the O2 concn. of the mixed gas at 3% or below, and to made the relative ratio CO to O2 satisfy the following equation: CO%>=O2% x2+1%. |
