Device system and method having sintering flue gas CO catalytic heat exchange and medium-and-low-temperature SCR denitration connected in series

A method for sintering flue gas having CO catalytic heat exchange in series with medium/low-temperature SCR denitration, which is performed with a device system for sintering flue gas having CO catalytic heat exchange in series with medium/low-temperature SCR denitration;

• the device system comprises a CO catalytic regenerative heat exchange device, an ammonia spray device, and a medium/low-temperature SCR denitration reaction device which are sequentially connected along the flow direction of raw flue gas;
• a sintering flue gas inlet of the CO catalytic regenerative heat exchange device is directly connected to a desulfurized raw flue gas pipeline;
• a purified flue gas outlet of the medium/low-temperature SCR denitration reaction device is connected to a denitrated flue gas inlet of the CO catalytic regenerative heat exchange device;
• a CO heat-regenerative catalyst comprises a cordierite honeycomb ceramic heat-regenerative framework and an active component which is arranged on the cordierite honeycomb ceramic heat-regenerative framework
• the cordierite honeycomb ceramic heat-regenerative framework has a porosity of 0.5-0.7;
• the method comprises the following steps:
• (1) subjecting sintering flue gas to the CO catalytic regenerative heat exchange device to perform a first CO catalytic conversion and heat the sintering flue gas to obtain heated flue gas;
• (2) mixing the heated flue gas with an ammonia source by the ammonia spray device, and then introducing into the medium/low-temperature SCR denitration reaction device to perform an SCR denitration reaction to obtain denitrated flue gas;
• a temperature of the heated flue gas which is introduced into the ammonia spray device in step (2) is 220-280° C., and a complete reaction temperature of the CO heat-regenerative catalyst in the CO catalytic regenerative heat exchange device is 180-220° C.;
• and
• (3) introducing the denitrated flue gas into the CO catalytic regenerative heat exchange device to perform heat exchange cooling and a second CO catalytic conversion to obtain purified sintering flue gas;
• using heat release from CO catalytic oxidation to replace heat supplement of hot blast furnace fuel and a heat exchanger device;
• wherein at the stage where the process of step (1) is being started up, the heated flue gas is subjected a hot blast furnace device for heat supplement before introduced to the ammonia spray device;
• for the flue gas with a flow rate of 850000 Nm3/h, the total system pressure drop is less than or equal to 1900 Pa;
• the consumption of blast furnace gas is less than or equal to 50000 m3 in 30 days;
• the NOx concentration in the purified flue gas is less than or equal to 40 mg/m3, and the CO concentration in the purified flue gas is less than or equal to 500 mg/m3.