Method for controlling coal injecting rate of blast furnace

Abstract

The invention relates to a method for controlling the coal injecting rate of a blast furnace, which is used for mainly controlling an air supply regulating valve, a small diffusion stop valve, a fluidization regulating valve and a conveyed air regulating valve to realize the control for the injecting rate by adopting a parallel-connection injection mode with more than two tanks. The method comprises the following steps of: stabilizing the pressure of injecting tanks by regulating the air supply regulating valve and the small diffusion stop valve, stabilizing the air carrier volume by regulating the conveyed air regulating valve, and then forming a PID (Proportion Integration Differentiation) cascade control loop by regulating the injecting rate and the fluidized air flow under the conditions of the stable pressure and air carrier volume of the injecting tanks, wherein the PID cascade control loop is used for rapidly and uniformly regulating the injecting rate; and processing the relation among the tank pressure, the air carrier volume and the fluidized air flow with the injecting rate in a production process according to the process requirement so that the injecting rate is effectively controlled, thereby creating conditions for the smooth production of the blast furnace. The method can effectively prevent furnace pressure fluctuation from interfering the injecting rate and prevent hysteresis and great fluctuation generated in the regulation process of the tank pressure, ensures the rapid, stable and uniform regulation of the tank pressure, and has simple process.

Description

technical field [0001] The invention relates to the technical field of blast furnace automatic control, in particular to a method for controlling the blast furnace coal injection rate. 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, a...

AI Technical Summary

Problems solved by technology

Under normal circumstances, 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 measured injection volume with the set injection volume, and use the proportional integral derivative (PID) algorithm to control the tank pressure. The control of the tank pressure is realized by adjusting the amount of air supply. 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. At this time, the air supply The 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. , so 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 setting After setting the value, at this time, since the tank pressure has reached the set tank pressure, but at this time the air supply valve does not close immediately but keeps closing and then slowly closes, resulting in the tank pressure still increasing and the injection rate rising continuously, resulting in a large overshoot. Harmonize fluctuations

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

Images