JPS56169734A - Method of recovering waste heat of sintering exhaust gas - Google Patents

Abstract

PURPOSE: To desufurize, oxidize CO, and denitrate the exhaust gas before the completion of burning and to pass the exhaust gas after the completion of burning through a waste heat recovering unit to recover effectively both the sensible heat of the exhaust gas and the latent heat of the CO.

CONSTITUTION: Exhaust gas before the completion of burning 2 leaving a sintering machine 1 is sent through a wind box 3, a blower 4 and a heat exchanger 5 to desulfurizing unit 6 and desulfurized therein. Subsequently, desulfurized exhaust gas 2 is heated by heat exchanger 8, is mixed with an exhaust gas from a heating furnace 9 to raise its temperature, and then the mixed exhaust gas is sent to an oxidation reactor 10. In one of the oxidation reactors 10, exhaust gas 2 is brought into contact with a Pt-containing CO oxidation catalyst to oxidize CO. The heat of the resulting exhaust gas having the temperature being raised is partially recovered by a heat exchanger 11 before the exhaust gas is denitrated by a denitrating unit 12 and then the exhaust gas is emitted through a heat exchanger 8 and a heat recovery unit 13 to the outside for discharge. On the other hand, air having a temperature of 300°C or higher or sintering exhaust gas having a temperature of 420°C or higher is passed through the other oxidation reactor 14 to regenerate the catalyst. The entire or a part of the exhaust gas 7 from the section between after the completion of burning and ore dropping of the total exhaust gas is sent to a waste heat recovery unit 16 to recover the sensible heat before it is exhausted to the outside. A power generator 17 is operated with the steam generated by a unit 16.

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