Method for accurately controlling top pressure of blast furnace through electric pressure regulating valve group

Abstract

The invention relates to a method for accurately controlling the top pressure of a blast furnace by an electric pressure regulating valve group. And the electric pressure regulating valve group consists of four electric butterfly valves which are connected in parallel. After the blast furnace is discharged, the air permeability of the blast furnace becomes poor, the pressure difference rises, and the furnace top pressure drops sharply, the opening degree of the pressure regulating valve group needs to be reduced to reduce the outflow of furnace top gas, so that the furnace top pressure does not drop any more. The action of the electric pressure regulating valve set is slow, when it is detected that the pressure of the furnace top is reduced, the opening degree of the pressure regulating valve set is reduced, and at the moment, the top pressure is reduced. In order to overcome the control lag phenomenon, a feedforward + PID control method is adopted, and the opening degree of a pressure regulating valve group is reduced in advance to control top pressure. The feedforward utilizes the material level height, a stock rod lifting instruction to a stock line, a stock rod to a certain position, a lower sealing valve opening instruction, a lower sealing valve opening in place, a material flow adjusting valve opening instruction, a material flow valve opening to a certain position, a certain signal of a furnace top and other signals before discharging start to trigger a pressure adjusting valve group control instruction, so that the control lag phenomenon is overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of ironmaking industry, and in particular relates to a blast furnace electric pressure regulating valve group for accurately controlling the blast furnace top pressure. Background Art

[0002] Blast furnace top pressure control is now generally controlled by turbines. This control method can recover the kinetic energy of blast furnace gas and accurately control the blast furnace top pressure. However, turbines have strict requirements on gas quality. Under special working conditions such as low blast furnace gas pressure, small flow, high temperature, and high dust content, turbines cannot operate normally. When the blast furnace gas quality is poor, the blast furnace is in special working conditions, and the turbine is under maintenance, the pressure regulating valve group is a good supplement to the blast furnace top pressure control.

[0003] There are several control algorithms for blast furnace top pressure using electric pressure regulating valve group: 1. Use the "difference algorithm between the set value of the blast furnace top pressure and the actual value of the top pressure" to control the electric pressure regulating valve group (disadvantages: the electric actuator has slow action, long action time, frequent action, and delayed control of the top pressure, resulting in large fluctuations in the blast furnace top pressure).

[0004] 2. Use the "PID algorithm" to control the electric pressure regulating valve group (disadvantages: the electric actuator has slow action, long action time, frequent action, and delayed control of the furnace top pressure, resulting in large fluctuations in the blast furnace top pressure).

[0005] Use "PID algorithm, servo valve" to control the hydraulic pressure regulating valve group (disadvantages: high investment and maintenance costs). Summary of the invention

[0006] The electric pressure regulating valve group is controlled by using the "feedforward control + PID algorithm" method.

[0007] The main reason for the fluctuation of blast furnace top pressure is that the permeability of the material column weakens and the top pressure drops when the blast furnace is loaded. This feature is used to adopt the "feedforward control + PID algorithm" control method to overcome the fluctuation of furnace top pressure.

[0008] When the blast furnace is about to be or is being loaded, the electric pressure regulating valve group is controlled to advance a certain opening to realize the advance control of the blast furnace top pressure. The command of the advance control pressure regulating valve group is issued by using the material line, the probe, the probe to a certain position, the lower sealing valve opening command, the lower sealing valve opening in place, the material flow regulating valve opening command, the material flow valve opening to a certain position, or a certain signal from the blast furnace top. Due to the different permeability of ore and coke, different types of materials, different blast furnace capacities, etc., the specific signal used for the feedforward command, the advance action opening of the pressure regulating valve group, and the PID parameters to be used need to be determined according to the actual debugging situation.

[0009] Compared with the prior art, the beneficial effects of the present invention are: eliminating the occurrence of hysteresis phenomenon of blast furnace top pressure control, compensating for the shortcoming of slow action of the electric pressure regulating valve group, and reducing the fluctuation range of blast furnace top pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a simplified diagram of the blast furnace top equipment; Figure 2 It is the control logic diagram; 1. Receiving hopper; 2. Material stop valve; 3. Upper sealing valve; 4. Material tank; 5. Material flow regulating valve; 6. Lower sealing valve; 7. Material distributor; 8. Probe. DETAILED DESCRIPTION

[0011] The furnace top pressure is collected to PLC using pressure transmitter, the furnace top pressure setting is set in upper computer (industrial computer) and transmitted to PLC, feedforward signal (material line arrival, raising probe 8, probe 8 to a certain position, instruction to open lower sealing valve 6, lower sealing valve 6 opened to position, instruction to open material flow regulating valve 5, material flow regulating valve 5 opened to a certain position, or a certain signal of blast furnace top) is collected to PLC, all signals are calculated in PLC and then PLC issues instruction to control the opening of electric pressure regulating valve group.

Claims

1. A method for accurately controlling the top pressure of a blast furnace by using an electric pressure regulating valve group. It is characterized by The blast furnace top pressure is set on the host computer, and this set pressure is transmitted to the PLC by the host computer. The blast furnace top pressure is measured by the pressure transmitter and transmitted to the PLC. When the measured top pressure deviates from the set top pressure, the PLC calculates the control instructions through the written program to control the opening of the electric pressure regulating valve group, thereby realizing the control of the blast furnace top pressure. The electric pressure regulating valve group is composed of four parallel electric butterfly valves. When the blast furnace is about to be or is being loaded, the electric pressure regulating valve group is controlled in advance, and the feedforward control method is used to advance the opening to realize the advanced control of the blast furnace top pressure.

2. A method for accurately controlling the top pressure of a blast furnace by using an electric pressure regulating valve group according to claim 1, characterized in that The feedforward signal utilizes the material surface height, material line arrival, probe raising instruction, probe reaching a certain position, lower sealing valve opening instruction, lower sealing valve opening to position, material flow regulating valve opening instruction, material flow valve opening to a certain position, or a certain signal from the blast furnace top to issue an instruction for advance control of the pressure regulating valve group.

3. A method for accurately controlling the top pressure of a blast furnace by using an electric pressure regulating valve group according to claim 1, characterized in that The feedforward control signal may be used in one or more combinations.

4. A method for accurately controlling the top pressure of a blast furnace by using an electric pressure regulating valve group according to claim 1, characterized in that The electric pressure regulating valve group includes four electric butterfly valves connected in parallel.

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