Carbon fiber waste gas treatment incinerator negative pressure control method

Abstract

The application discloses a kind of carbon fiber waste gas treatment incinerator negative pressure control method, belongs to electrical automation control technical field;For adjusting the pressure range of carbon fiber waste gas treatment system, the carbon fiber waste gas treatment system includes direct-fired incinerator, boiler, telescopic soot blower, variable frequency fan and PLC controller, control method includes the parameter setting of first segment PID control mode and second segment PID control mode, the operating frequency setting of first fixed frequency mode and second fixed frequency mode of variable frequency fan, the start and stop signal of telescopic soot blower is collected, the key time point before the pressure of direct-fired incinerator in hearth sudden increase and pressure sudden decrease is collected 1-2 seconds, the operating frequency of variable frequency fan is switched by PLC controller, to reach the purpose of stabilizing the hearth negative pressure of direct-fired incinerator.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrical automation control, and particularly relates to a carbon fiber waste gas treatment incinerator negative pressure control method. BACKGROUND

[0002] In the production process of carbon fiber, high-carbon furnace and low-carbon furnace and other equipment are needed, and the waste gas generated by the high-carbon furnace and low-carbon furnace equipment when working enters the direct-fired incinerator for combustion treatment, which will produce a large amount of dust (silicon powder). These dusts will adhere to the inside of the boiler, greatly reducing the energy recovery efficiency of the boiler. Therefore, a telescopic soot blower is added to the boiler to blow off the dust inside the boiler at regular intervals.

[0003] When the telescopic soot blower is working, the air volume entering the system gradually increases, reaches a peak and then gradually decreases to 0. This process will cause large fluctuations in the negative pressure of the incinerator, which is not conducive to the combustion of the system and the high-carbon furnace and low-carbon furnace equipment will overflow harmful gas. The root cause of this problem is that the original PID control negative pressure balance is destroyed by the large amount of compressed air entering instantaneously when the telescopic soot blower is working. The original PID control cannot handle the large air volume entering instantaneously, so the control method needs to be improved. SUMMARY

[0004] The application mainly solves the technical problems existing in the prior art and provides a carbon fiber waste gas treatment incinerator negative pressure control method.

[0005] The above technical problems of the application are mainly solved by the following technical scheme: a carbon fiber waste gas treatment incinerator negative pressure control method for adjusting the pressure range of a carbon fiber waste gas treatment system, characterized by comprising:

[0006] a direct-fired incinerator for burning and treating waste gas;

[0007] a boiler, which is connected to the direct-fired incinerator through a pipeline and is used for treating and recovering the heat generated by the direct-fired incinerator when working;

[0008] a variable frequency fan, which is connected to the boiler through a pipeline and is used for stabilizing the pressure in the direct-fired incinerator and discharging the waste gas after combustion treatment;

[0009] a telescopic soot blower, which is installed on the boiler and is used for intermittently cleaning the dust inside the boiler;

[0010] a PLC controller, which is used for user operation to set the parameters required by the user, control the variable frequency fan and monitor the telescopic soot blower;

[0011] The control method comprises:

[0012] Step 1: according to the user's needs, the parameters of the first segment PID control mode and the second segment PID control mode are set on the PLC controller;

[0013] Step 2: according to the user's needs, the running frequency of the first fixed frequency mode and the second fixed frequency mode of the variable frequency fan is set;

[0014] Step 3: the start and stop signals of the telescopic soot blower are collected, and the key time points of the sudden increase and sudden decrease of the pressure in the furnace of the direct-fired incinerator are collected;

[0015] Step 4: when the PLC controller monitors that the telescopic soot blower is started and the pressure in the furnace of the direct-fired incinerator suddenly increases, the control of the first segment PID control parameter on the variable frequency fan is interrupted, and after the variable frequency fan enters the first fixed frequency mode and is controlled by the second segment PID control parameter, the control of the variable frequency fan is taken over by the first segment PID control parameter;

[0016] Step 5: when the PLC controller monitors that the telescopic soot blower is started and the pressure in the furnace of the direct-fired incinerator suddenly decreases, the control of the second segment PID control parameter on the variable frequency fan is interrupted, and after the variable frequency fan enters the second fixed frequency mode and is controlled by the first segment PID control parameter, the control of the variable frequency fan is taken over by the first segment PID control parameter as preferred, the parameters of the first segment PID control mode include the furnace negative pressure PV value of the incinerator, the SV target value and the LMN adjustment variable, wherein the SV target value is-200Pa, the LMN adjustment variable: the P proportion value is-1.0, the I integral value is 20000ms, the D differential value is 0ms, and the furnace negative pressure PV value of the incinerator is input according to the actual user.

[0017] As preferred, the parameters of the second segment PID control mode include the furnace negative pressure PV value of the direct-fired incinerator, the SV target value and the LMN adjustment variable, wherein the SV target value is-200Pa, the LMN adjustment variable: the P proportion value is-4.3, the I integral value is 20000ms, the D differential value is 0ms, and the furnace negative pressure PV value of the direct-fired incinerator is input according to the actual user.

[0018] As preferred, the variable frequency fan runs in variable frequency mode under the first segment PID control mode and the second segment PID control mode, and the running frequency of the variable frequency mode is 35-40HZ / min.

[0019] As preferred, the running frequency of the first fixed frequency mode of the variable frequency fan is increased by 1-2HZ / min based on the running frequency of the variable frequency mode.

[0020] As preferred, the running frequency of the second fixed frequency mode of the variable frequency fan is reduced by 1-2HZ / min based on the running frequency of the variable frequency mode.

[0021] The present application has the beneficial effects of:

[0022] The present application has the beneficial effects of:

[0023] The present application has the beneficial effects of: BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a structural schematic diagram of the carbon fiber waste gas treatment system of the present application;

[0025] Figure 2 is a schematic diagram of the air volume trend of the telescopic soot blower;

[0026] Figure 3 is a schematic diagram of the negative pressure fluctuation in the direct combustion incinerator when the telescopic soot blower works under the first segment PID control mode;

[0027] Figure 4 is a schematic diagram of the negative pressure fluctuation in the direct combustion incinerator when the telescopic soot blower works under the second segment PID control mode. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be further specifically explained below through embodiments and in combination with the drawings.

[0029] The technical solutions of the present application will be further specifically explained below through embodiments and in combination with the drawings. Figures 1-4 The technical solutions of the present application will be further specifically explained below through embodiments and in combination with the drawings.

[0030] Embodiment: A kind of carbon fiber waste gas treatment incinerator negative pressure control method, for adjusting the pressure range of carbon fiber waste gas treatment system, the carbon fiber waste gas treatment system includes: PLC controller, direct-fired incinerator, boiler, telescopic soot blower and variable frequency fan, direct-fired incinerator is used to burn the hot gas generated when high-carbon furnace or low-carbon furnace works, boiler is used to process the heat when recovering direct-fired incinerator combustion waste gas, telescopic soot blower is used to periodically clean the dust in boiler, variable frequency fan is used to discharge the waste gas after combustion treatment and stabilize the pressure in direct-fired incinerator, PLC controller is used to control variable frequency fan according to the parameter setting required by user and monitor the working state of telescopic soot blower and collect signal.

[0031] The control method comprises:

[0032] Step 1: according to the parameter setting of the first segment PID control mode and the second segment PID control mode on the PLC controller required by user;

[0033] Step 2: according to the required frequency setting of the first fixed frequency mode and the second fixed frequency mode of variable frequency fan by user;

[0034] Step 3: collect the start and stop signals of telescopic soot blower, collect the key time points of pressure sudden increase and pressure sudden decrease in the hearth of direct-fired incinerator;

[0035] Step 4: when PLC controller monitors that telescopic soot blower starts and the pressure in the hearth of direct-fired incinerator suddenly increases, the first segment PID control parameter interrupts the control of variable frequency fan, and after variable frequency fan enters the first fixed frequency mode and runs, the second segment PID control parameter takes over the control of variable frequency fan;

[0036] Step 5: when PLC controller monitors that telescopic soot blower starts and the pressure in the hearth of direct-fired incinerator suddenly decreases, the second segment PID control parameter interrupts the control of variable frequency fan, and after variable frequency fan enters the second fixed frequency mode and runs, the first segment PID control parameter takes over the control of variable frequency fan.

[0037] In the step 1, the parameters of the first PID control mode are as follows: the SV target value is -200 Pa, the LMN adjusting variable: P proportional value is -1.0, I integral value is 20000 ms, and D differential value is 0 ms; the PV value of the furnace inner negative pressure of the direct combustion incinerator is input by the user; the parameters of the second PID control mode are as follows: the SV target value is -200 Pa, the LMN adjusting variable: P proportional value is -4.3, I integral value is 20000 ms, and D differential value is 0 ms; the PV value of the furnace inner negative pressure of the direct combustion incinerator is input by the user; the frequency of the variable frequency fan in the variable frequency mode is 35-40 HZ / min; and the rated rotating speed of the variable frequency fan is 2975 rpm / min.

[0038] The start and stop of the telescopic soot blower are controlled by the Q point output of the PLC, 1 is start, and 0 is stop; the sudden increase and decrease of the pressure in the direct combustion incinerator is related to the increase and decrease of the air volume of the telescopic soot blower in the boiler; the increase of the air volume of the telescopic soot blower will cause the sudden increase of the pressure in the furnace, and vice versa; the increase and decrease of the air volume of the telescopic soot blower can be judged according to the change curve of the furnace inner negative pressure of the direct combustion incinerator; when the PLC controller receives the start signal of the soot blower and monitors the sudden increase of the pressure in the furnace of the direct combustion incinerator, the variable frequency fan exits the first PID control mode and enters the first fixed frequency mode 1-2 seconds before the pressure increases (the critical time point of the pressure increase), so as to achieve the purpose of quickly extracting the increased air volume and stabilizing the furnace negative pressure; after the variable frequency speed-up is completed, the variable frequency fan enters the second PID control mode; when the PLC controller monitors the sudden decrease of the pressure in the furnace of the direct combustion incinerator, the PLC controller makes the variable frequency fan exit the second PID control mode and enter the second fixed frequency mode 1-2 seconds before the pressure decreases (the critical time point of the pressure decrease), so as to prevent the variable frequency fan from being too strong when the air volume of the telescopic soot blower decreases suddenly, and thus achieve the purpose of stabilizing the furnace inner negative pressure.

[0039] Finally, it should be noted that the above embodiments are only representative examples of the present application. Obviously, the present application is not limited to the above embodiments, and there can be many variations. Any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments shall be considered as falling within the protection scope of the present application.

Claims

1. A method for controlling negative pressure in a carbon fiber waste gas treatment incinerator, used to adjust the pressure range of the carbon fiber waste gas treatment system, characterized in that: The carbon fiber exhaust gas treatment system includes: Direct-fired incinerators are used to burn and treat waste gases; The boiler is connected to the direct-fired incinerator via a pipeline and is used to process and recover the heat generated during the operation of the direct-fired incinerator. Variable frequency fan; the variable frequency fan is connected to the boiler via a pipeline, and the variable frequency fan is used to stabilize the pressure inside the direct-fired incinerator and to discharge the exhaust gas after combustion treatment. Telescopic soot blower; the telescopic soot blower is installed on the boiler and is used to intermittently clean the dust inside the boiler. PLC controller; used for user operation and setting of required parameters to control the variable frequency fan and monitor the telescopic soot blower; The control method includes: Step 1: Set the parameters for the first and second PID control modes on the PLC controller according to the user's requirements. Step 2: Set the operating frequency of the variable frequency fan in the first fixed frequency mode and the second fixed frequency mode according to the user's needs; Step 3: Collect the start and stop signals of the telescopic soot blower, and collect the key time points of sudden pressure increase and sudden pressure decrease in the furnace of the direct-fired incinerator; Step 4: When the PLC controller detects that the telescopic soot blower has started and the pressure inside the furnace of the direct-fired incinerator has suddenly increased, it interrupts the control of the variable frequency fan by the first stage of PID control parameters. After the variable frequency fan enters the first fixed frequency mode, the control of the variable frequency fan is taken over by the second stage of PID control parameters. Step 5: When the PLC controller detects that the telescopic soot blower has started and the pressure inside the furnace of the direct-fired incinerator has dropped sharply, it interrupts the control of the variable frequency fan by the second stage PID control parameters. After the variable frequency fan enters the second fixed frequency mode, the control of the variable frequency fan is taken over by the first stage PID control parameters. The operating frequency of the first fixed-frequency mode of the variable frequency fan is increased by 1-2 Hz / min based on the operating frequency of the variable frequency mode; The operating frequency of the second fixed-frequency mode of the variable frequency fan is reduced by 1-2 Hz / min based on the operating frequency of the variable frequency mode.

2. The negative pressure control method for a carbon fiber waste gas treatment incinerator according to claim 1, characterized in that: The parameters of the first PID control mode include the negative pressure PV value inside the furnace of the direct-fired incinerator, the target SV value, and the LMN adjustment variable. The target SV value is -200Pa, and the LMN adjustment variable has the following values: P proportional value -1.0, I integral value 20000ms, and D derivative value 0ms. The negative pressure PV value inside the furnace of the direct-fired incinerator is based on the actual input of the user.

3. The negative pressure control method for a carbon fiber waste gas treatment incinerator according to claim 1, characterized in that: The parameters of the second PID control mode include the negative pressure PV value inside the furnace of the direct-fired incinerator, the target SV value, and the LMN adjustment variable. The target SV value is -200Pa, and the LMN adjustment variables are: P proportional value -4.3, I integral value 20000ms, and D derivative value 0ms. The negative pressure PV value inside the furnace of the direct-fired incinerator is based on the actual input of the user.

4. The negative pressure control method for a carbon fiber waste gas treatment incinerator according to claim 1, characterized in that: In both the first and second PID control modes, the variable frequency fan operates in variable frequency mode, and the operating frequency of the variable frequency mode is 35-40 Hz / min.

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