JPS57161011A - Temperature controlling method for blast furnace gas - Google Patents

Abstract

PURPOSE: To keep the temp. of a blast furnace gas within a permissible heat resistance range of filter cloths by providing a fluid injection system in two stages between the blast furnace top and a dry type dust remover, and making independent or combination use of two stages of sprays in accordance with the degrees of rising of the temp. of the blast furnace gas.

CONSTITUTION: The detected value with a thermometer 14 near the outlet of a dry type dust remover 3 is compared with the set value, and is subjected to PID operation, the result whereof is inputted to an adder 16. The detected value with a thermometer 17 of a downcomer 18 of a blast furnace is inputted via a time delay operator 19 to a rate setter 20 which converts this to a rate signal and inputs the same to the adder 16, where it is added to the operated signal of the controller 15 and is inputted to a multiplier 21. On the other hand, the flow rate of the blast of a hot stove 22 is detected with a flowmeter 23, and is inputted to the multiplier 21, which multiplies this by the signal from the adder 16, and emits operation signals for control valves 12, 13. The operations of the valves 12, 13 by the operation signal of the multiplier 21 are properly controlled independently or in combination by rate setters 24, 25, whereby the rates of injection of water through water injection nozzles 4, 5 are properly controlled.

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