Coal injection system of blast furnace

Abstract

The invention relates to a coal injection system of a blast furnace, which comprises a plurality of injection tanks, wherein the upper parts of the injection tanks are connected with a coal powder bin (1) through pipelines, charging dump valves (14) and blanking dump valves (15) for injection of materials in the tanks, and are respectively connected with the coal powder bin through pipelines, small bleeding dump valves (12) and large bleeding dump valves (13) for bleeding of the injection tanks at the same time; the middle parts of the injection tanks are respectively connected with a nitrogen pressure regulating station (2) through three connecting pipelines and valves in three ways, wherein one way is used for pressure complement of the injection tanks, one way is used for pressure recharging of the injection tanks, and the last way is used for fluidizing the coal powder in the injection tanks; and the lower parts of the injection tanks are respectively connected with a mixer (4) through pipelines and coal injection dump valves (19), and the mixer is connected with a dispenser (5) and each blast hole of a blast furnace (6) through pipelines. The invention can effectively prevent interference of furnace pressure fluctuation on the injection rate, prevent lagging and large fluctuation in the process of tank pressure regulation and ensure the fast, stable and uniform regulation of tank pressure.

Description

technical field [0001] The invention relates to the technical field of blast furnace automatic control, in particular to a blast furnace coal injection system. Background technique [0002] Blast furnace coal injection technology is the central link of blast furnace system structure optimization, which has the advantages of greatly reducing the coke ratio, improving economic benefits, and reducing environmental pollution. Coal injection technology, as a major trend in the development of blast furnace ironmaking technology at home and abroad, is one of the three important technical routes for the development of my country's iron and steel industry. With the development of coal injection technology in the direction of high injection rate dense phase transportation, how to adjust the amount of pulverized coal injection stably, uniformly and accurately is an important basis for maintaining stable furnace temperature, ensuring smooth furnace conditions, and making the blast furna...

AI Technical Summary

Problems solved by technology

In general, the control of the injection rate is to rely on manual experience or a semi-automatic method to fix the delivery gas flow rate, and then compare the actual injection volume with the set injection volume, and use the proportional integral derivative (PID) algorithm to control the tank pressure. , and the control of the tank pressure is realized by adjusting the amount of air supplement. For this adjustment method, when the coal injection rate deviates from the set value, the control program will automatically increase or decrease the set value of the tank pressure. The air regulating valve will be adjusted according to the deviation between the actual value of the tank pressure and the set value. Since it is a relatively slow process to change the tank pressure through the amount of air supply, and because there is no online detection instrument for the injection rate, the calculation of the injection rate is lagging behind. Therefore, it is a huge lag process for changing the injection rate; on the other hand, when the tank pressure is slowly increasing, the injection rate cannot be increased immediately, resulting in a continuous increase in the amount of air supply, and when the injection rate reaches the expected After setting the value, since the tank pressure has reached the set tank pressure at this time, but at this time the air supply valve does not close immediately but keeps and then closes slowly, resulting in the tank pressure still increasing and the injection rate rising continuously, resulting in a large overshoot and fluctuation

According to the above analysis, it is impossible to achieve stable and uniform control of the injection volume only through conventional PID control, and there is a serious lag, which is likely to cause large fluctuations in the injection volume and blockage of pulverized coal, thereby affecting the normal production of the blast furnace and even destroying the furnace condition. cause wind

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