A control system and control method of waste gas burner

Abstract

The present invention discloses a control system and a control method for an exhaust gas burner. The control system includes a PLC controller, a burner, a temperature measuring device, a natural gas flow regulating valve, a natural gas flow transmitter, an exhaust gas solenoid valve and an exhaust gas pressure transmitter. The output end of the burner is connected to the temperature measuring device. The input end of the burner is provided with a natural gas input end and an exhaust gas input end. The natural gas input end is connected to the output end of the natural gas flow regulating valve. The output end of the natural gas flow regulating valve is also connected to the natural gas flow transmitter. The exhaust gas input end is connected to the output end of the exhaust gas solenoid valve. The input end of the exhaust gas solenoid valve is connected to the exhaust gas pressure transmitter. The PLC controller is electrically connected to the temperature measuring device, the natural gas flow regulating valve, the natural gas flow transmitter, the exhaust gas solenoid valve and the exhaust gas pressure transmitter respectively. Beneficial effect: The control system can realize automatic adjustment and control of the burner, which can not only maintain stable combustion to ensure full combustion of the exhaust gas, but also fully recycle and utilize energy.

Description

Technical Field

[0001] The invention relates to the technical field of thermal desorption treatment, and in particular to a control system and a control method of a waste gas burner. Background Art

[0002] The thermal desorption device is an indirect heating treatment process for oily waste. During the treatment process, a large amount of volatile VOCs, semi-volatile SVOCs, non-volatile organic pollutants and volatile heavy metals (Hg, As, etc.) will be gasified. If the gasified gas mixture is directly discharged into the atmosphere, it will cause secondary pollution to the air. A separate exhaust gas treatment system will greatly increase the equipment cost and is not conducive to energy recycling. If a burner is configured for the mixed exhaust gas and the mixed exhaust gas is burned as an independent fuel, it can not only burn the organic exhaust gas to meet the national emission standards and reduce the pollution of the environment by emissions, but also meet the energy recycling needs to a certain extent. However, the amount of exhaust gas generated during the thermal desorption process and the combustible components contained in the exhaust gas are unstable. If the amount of exhaust gas generated is too small or the combustible components are too few, the burner will be difficult to maintain stable combustion and may even extinguish, causing the exhaust gas to be discharged into the atmosphere and pollute the environment; if the amount of exhaust gas generated is too large, the burner will not be fully burned, causing a large amount of exhaust gas to be discharged into the atmosphere with the flue gas, and there is a possibility of secondary pollution. Therefore, there is an urgent need for a new type of burner that can ensure continuous, stable and sufficient combustion of exhaust gas and stable output of burner heat. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a control system for an exhaust gas burner, which can realize automatic adjustment and control of the burner. When natural gas is burned alone, the amount of natural gas introduced into the burner is automatically adjusted and controlled according to the temperature change of the burner; when the burner is mixed with combustion, the start and stop of exhaust gas combustion and the amount of natural gas introduced are automatically adjusted and controlled according to the temperature change of the burner and the changes in the pressure and flow of the exhaust gas. At the same time, the amount of combustion-supporting air introduced into the burner is automatically adjusted and controlled according to the amount of natural gas entering, the start and stop of exhaust gas combustion, and the changes in the pressure and flow of the exhaust gas. Automatic control and adjustment of three combustion states can be realized: burning natural gas alone, burning natural gas and exhaust gas together, and burning exhaust gas alone. It can maintain stable combustion to ensure full combustion of exhaust gas and reduce emission pollution, and it can fully recycle and utilize energy, while maintaining the stable output of the burner heat.

[0004] The objective of the present invention is achieved through the following technical measures: a control system for an exhaust gas burner, the control system comprising a PLC controller, a burner, a temperature measuring device, a natural gas flow regulating valve, a natural gas flow transmitter, an exhaust gas solenoid valve and an exhaust gas pressure transmitter, the output end of the burner is connected to the temperature measuring device, the input end of the burner is provided with a natural gas input end and an exhaust gas input end, the natural gas input end is connected to the output end of the natural gas flow regulating valve, the output end of the natural gas flow regulating valve is also connected to the natural gas flow transmitter, the exhaust gas input end is connected to the output end of the exhaust gas solenoid valve, the input end of the exhaust gas solenoid valve is connected to the exhaust gas pressure transmitter, and the PLC controller is electrically connected to the temperature measuring device, the natural gas flow regulating valve, the natural gas flow transmitter, the exhaust gas solenoid valve and the exhaust gas pressure transmitter respectively.

[0005] Furthermore, the control system also includes an air ratio regulating valve, the input end of the burner is also provided with an air input end, the air input end is connected to the output end of the air ratio regulating valve, and the air ratio regulating valve is electrically connected to the PLC controller.

[0006] Furthermore, the control system further comprises a natural gas solenoid valve, an output end of the natural gas solenoid valve is connected to an input end of the natural gas flow regulating valve, and the natural gas solenoid valve is electrically connected to the PLC controller.

[0007] Furthermore, the control system also includes an exhaust gas flow transmitter, which is connected to the output end of the exhaust gas solenoid valve and is electrically connected to the PLC controller.

[0008] A control method for an exhaust gas burner, the control method comprising the following steps:

[0009] (1) Natural gas combustion stage: The PLC controller receives the instantaneous temperature of the burner output end monitored by the temperature measuring device and compares it with the set temperature in the PLC controller. If the instantaneous temperature is less than the set temperature, the PLC controller starts the natural gas solenoid valve, and the natural gas enters the burner through the pipeline for combustion. The natural gas flow transmitter transmits the monitored natural gas flow signal to the PLC controller. The PLC controller adjusts the opening of the natural gas flow control valve according to the instantaneous temperature and the natural gas flow signal, thereby controlling the input amount of natural gas at the burner input end. At the same time, the PLC controller adjusts the opening of the air ratio control valve according to the natural gas flow signal, thereby controlling the input amount of air at the burner input end.

[0010] (2) Mixed combustion of natural gas and exhaust gas: The PLC controller opens the exhaust gas solenoid valve, and the exhaust gas enters the burner for combustion. The exhaust gas pressure transmitter transmits the monitored exhaust gas pressure signal to the PLC controller, and the exhaust gas flow transmitter feeds back the monitored exhaust gas flow signal to the PLC controller. At this time, the PLC controller ensures that the opening of the air ratio control valve remains unchanged. The PLC controller reduces the opening of the natural gas flow control valve according to the exhaust gas pressure signal and the exhaust gas flow signal, thereby reducing the input amount of natural gas entering the burner. When the pressure and flow of the exhaust gas reach stability, the PLC controller adjusts the opening of the natural gas flow control valve according to the instantaneous temperature. If the instantaneous temperature is less than the set temperature, the opening of the natural gas flow control valve is increased. If the instantaneous temperature is greater than the set temperature, the opening of the natural gas flow control valve is decreased. At the same time, the PLC controller adjusts the opening of the air ratio control valve according to the instantaneous temperature, the natural gas flow change signal, and the exhaust gas pressure and flow change signal, thereby adjusting the input amount of air at the burner input end to ensure sufficient combustion of natural gas and exhaust gas.

[0011] (3) Exhaust gas combustion stage: The PLC controller closes the natural gas solenoid valve and adjusts the opening of the air ratio control valve according to the instantaneous temperature, exhaust gas pressure and flow change signals, thereby controlling the input amount of air at the burner input end to ensure sufficient combustion of the exhaust gas.

[0012] Furthermore, the PLC controller is provided with a set value for the exhaust gas pressure, and the exhaust gas pressure transmitter transmits the monitored real-time pressure change signal of the exhaust gas to the PLC controller. When the real-time pressure of the exhaust gas is greater than the set pressure, the PLC controller opens the exhaust gas solenoid valve.

[0013] Furthermore, in the stage of burning exhaust gas alone, if the instantaneous temperature of the burner monitored by the temperature measuring device is greater than the set temperature, the PLC controller controls the exhaust gas solenoid valve to close, the burner stops burning, and performs a temperature reduction process.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the control system of the waste gas burner can realize automatic adjustment and control of the burner. When natural gas is burned alone, the amount of natural gas introduced into the burner is automatically adjusted and controlled according to the temperature change of the burner; when the burner is mixed with combustion, the start and stop of the exhaust gas combustion and the amount of natural gas introduced are automatically adjusted and controlled according to the temperature change of the burner and the changes in the pressure and flow of the exhaust gas. At the same time, the amount of combustion-supporting air introduced into the burner is automatically adjusted and controlled according to the amount of natural gas entering, the start and stop of the exhaust gas combustion, and the changes in the pressure and flow of the exhaust gas. Automatic control and adjustment of three combustion states can be realized: burning natural gas alone, burning natural gas and exhaust gas together, and burning exhaust gas alone. It can maintain stable combustion to ensure full combustion of exhaust gas and reduce emission pollution, and it can fully recycle and utilize energy, while maintaining the stable output of the burner heat.

[0015] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the control system of the exhaust gas burner.

[0017] Among them, 1. burner, 2. temperature measuring device, 3. natural gas flow control valve, 4. natural gas solenoid valve, 5. natural gas flow transmitter, 6. exhaust gas solenoid valve, 7. exhaust gas pressure transmitter, 8. exhaust gas flow transmitter, 9. air ratio control valve. DETAILED DESCRIPTION

[0018] like Figure 1 As shown, a control system for an exhaust gas burner includes a PLC controller, a burner 1, a temperature measuring device 2, a natural gas flow regulating valve 3, a natural gas flow transmitter 5, an exhaust gas solenoid valve 6 and an exhaust gas pressure transmitter 7. The output end of the burner 1 is connected to the temperature measuring device 2. The temperature measuring device 2 is used to monitor the temperature of the flue gas output by the burner 1 and transmit the temperature parameter signal to the PLC controller. The input end of the burner 1 is provided with a natural gas input end and an exhaust gas input end. The natural gas input end is connected to the output end of the natural gas flow regulating valve 3. The output end of the natural gas flow regulating valve 3 is also connected to the natural gas flow transmitter 5. The amount of natural gas introduced is adjusted by the natural gas flow regulating valve 3. At the same time, the natural gas flow transmitter 5 at the output end of the natural gas flow regulating valve 3 can transmit the flow change signal of the natural gas to the PLC controller. The exhaust gas input end is connected to the output end of the exhaust gas solenoid valve 6. The input end of the exhaust gas solenoid valve 6 is connected to the exhaust gas pressure transmitter 7. The exhaust gas solenoid valve 6 controls the start and stop of the exhaust gas input, and the exhaust gas pressure transmitter 7 can transmit the exhaust gas pressure change signal to the PLC controller. The PLC controller is electrically connected to the temperature measuring device 2, the natural gas flow control valve 3, the natural gas flow transmitter 5, the exhaust gas solenoid valve 6 and the exhaust gas pressure transmitter 7 respectively. When natural gas is burned alone, the PLC controller controls the opening of the natural gas flow control valve 3 through the temperature change signal of the burner 1 monitored by the temperature measuring device 2; when natural gas and exhaust gas are mixed, the PLC controller controls the start and stop of the exhaust gas solenoid valve 6 through the pressure change signal transmitted by the exhaust gas pressure transmitter 7, and adjusts the opening of the natural gas flow control valve 3 through the temperature change signal and the natural gas flow change signal; when exhaust gas is burned alone, the PLC controller controls the opening or closing of the exhaust gas solenoid valve 6 through the temperature change signal and the exhaust gas pressure change signal.

[0019] The control system further comprises an air ratio regulating valve 9. The input end of the burner 1 is also provided with an air input end, the air input end is connected to the output end of the air ratio regulating valve 9, and the air ratio regulating valve 9 is electrically connected to the PLC controller. The amount of air introduced into the control system is regulated by adjusting the opening of the air ratio regulating valve 9. The PLC controller adjusts the opening of the air ratio regulating valve 9 through the flow change signal of the natural gas or the flow change signal of the exhaust gas, and then adjusts the amount of air introduced into the control system to ensure the full combustion of the natural gas and the exhaust gas and reduce emission pollution.

[0020] The control system further includes a natural gas solenoid valve 4, the output end of which is connected to the input end of the natural gas flow regulating valve 3, and the natural gas solenoid valve 4 is electrically connected to the PLC controller. The natural gas in the control system is connected and disconnected by starting and stopping the natural gas solenoid valve 4, and the PLC controller controls the start and stop of the natural gas solenoid valve 4 through a temperature change signal.

[0021] The control system further includes an exhaust gas flow transmitter 8, which is connected to the output end of the exhaust gas solenoid valve 6, and is electrically connected to the PLC controller. The exhaust gas flow transmitter 8 monitors the flow of the exhaust gas in the pipeline, and feeds back the exhaust gas flow change signal to the PLC controller.

[0022] A control method for an exhaust gas burner, the control method comprising the following steps:

[0023] (1) Natural gas combustion stage: The PLC controller receives the instantaneous temperature of the output end of the burner 1 monitored by the temperature measuring device 2 and compares it with the set temperature in the PLC controller. If the instantaneous temperature is less than the set temperature, the PLC controller starts the natural gas solenoid valve 4, and the natural gas enters the burner 1 through the pipeline for combustion. The natural gas flow transmitter 5 transmits the monitored natural gas flow signal to the PLC controller. The PLC controller adjusts the opening of the natural gas flow regulating valve 3 according to the instantaneous temperature and the natural gas flow signal, thereby controlling the input amount of natural gas at the input end of the burner 1. At the same time, the PLC controller adjusts the opening of the air ratio regulating valve according to the natural gas flow signal, thereby controlling the input amount of air at the input end of the burner 1.

[0024] (2) Mixed combustion of natural gas and exhaust gas: The PLC controller opens the exhaust gas solenoid valve 6, and the exhaust gas enters the burner 1 for combustion. The exhaust gas pressure transmitter 7 transmits the monitored exhaust gas pressure signal to the PLC controller, and the exhaust gas flow transmitter 8 feeds back the monitored exhaust gas flow signal to the PLC controller. At this time, the PLC controller ensures that the opening of the air ratio control valve 9 remains unchanged. The PLC controller reduces the opening of the natural gas flow control valve 3 according to the exhaust gas pressure signal and the exhaust gas flow signal, thereby reducing the input amount of natural gas entering the burner 1. When the pressure and flow of the exhaust gas reach stability, the PLC controller adjusts the opening of the natural gas flow control valve 3 according to the instantaneous temperature. If the instantaneous temperature is less than the set temperature, the opening of the natural gas flow control valve 3 is increased. If the instantaneous temperature is greater than the set temperature, the opening of the natural gas flow control valve 3 is decreased. At the same time, the PLC controller adjusts the opening of the air ratio control valve 9 according to the instantaneous temperature, the natural gas flow change signal, and the exhaust gas pressure and flow change signal, thereby adjusting the input amount of air at the input end of the burner 1 to ensure sufficient combustion of natural gas and exhaust gas.

[0025] (3) Exhaust gas combustion stage: The PLC controller closes the natural gas solenoid valve 4 and adjusts the opening of the air ratio control valve 9 according to the instantaneous temperature, exhaust gas pressure and flow change signal, thereby controlling the input amount of air at the input end of the burner 1 to ensure sufficient combustion of the exhaust gas.

[0026] The PLC controller is provided with a set value for the exhaust gas pressure. The exhaust gas pressure transmitter 7 transmits the monitored real-time pressure change signal of the exhaust gas to the PLC controller. When the real-time pressure of the exhaust gas is greater than the set pressure, the PLC controller opens the exhaust gas solenoid valve 6.

[0027] In the stage of burning exhaust gas alone, if the instantaneous temperature of the burner 1 monitored by the temperature measuring device 2 is greater than the set temperature, the PLC controller controls the exhaust gas solenoid valve 6 to close, the burner 1 stops burning, and performs a temperature reduction process.

[0028] Working principle:

[0029] During the thermal desorption process, the generation of waste gas is a process from nothing to something, from a small amount to a large amount. The amount of waste gas and the combustible components contained in the waste gas are unstable. Therefore, the combustion process of the waste gas may include one or more processes of burning natural gas alone, burning natural gas and waste gas together, and burning waste gas alone. The following is an example of a combustion process including three processes.

[0030] When the system is turned on, the PLC controller first receives the instantaneous temperature of the output end of the burner 1 monitored by the temperature measuring device 2, and compares it with the set temperature in the PLC controller. If the instantaneous temperature is less than the set temperature, the PLC controller starts the natural gas solenoid valve 4. At the same time, the exhaust gas pressure transmitter 7 transmits the monitored instantaneous pressure of the exhaust gas to the PLC controller, and compares it with the set pressure of the exhaust gas in the PLC controller. If the instantaneous pressure is less than the set pressure, the exhaust gas solenoid valve 6 remains closed. Natural gas enters the burner 1 through the pipeline for combustion. At this time, the natural gas flow transmitter 5 transmits the monitored natural gas flow signal to the PLC controller. The PLC controller adjusts the opening of the natural gas flow regulating valve 3 according to the instantaneous temperature and the natural gas flow signal, thereby controlling the amount of natural gas entering the input end of the burner 1. At the same time, the PLC controller adjusts the opening of the air ratio regulating valve 9 according to the natural gas flow signal, thereby controlling the amount of air input at the input end of the burner 1. At this time, the burner 1 is in the stage of burning natural gas alone.

[0031] During the thermal desorption treatment process, as the waste gas is generated, when the instantaneous pressure of the waste gas is greater than the set pressure, the PLC controller opens the waste gas solenoid valve 6, and the waste gas enters the burner 1 for combustion. At the same time, the waste gas pressure transmitter 7 transmits the monitored waste gas pressure signal to the PLC controller, and the waste gas flow transmitter 8 feeds back the monitored waste gas flow signal to the PLC controller. The burner 1 enters the stage of mixed combustion of natural gas and waste gas. At this time, the PLC controller ensures that the opening of the air ratio regulating valve 9 remains unchanged, that is, the amount of air entering the burner 1 remains unchanged. The PLC controller reduces the opening of the natural gas flow regulating valve 3 according to the waste gas pressure signal and the waste gas flow signal, reduces the input amount of natural gas entering the burner 1, and ensures the full combustion of the waste gas and natural gas. When the pressure and flow of the waste gas are stable, the PLC controller adjusts the opening of the natural gas flow regulating valve 3 according to the instantaneous temperature. If the instantaneous temperature is less than the set temperature, the opening of the natural gas flow regulating valve 3 is increased. If the instantaneous temperature is greater than the set temperature, the opening of the natural gas flow regulating valve 3 is reduced. At the same time, the PLC controller adjusts the opening of the air ratio control valve 9 according to the instantaneous temperature, natural gas flow change signal and exhaust gas pressure and flow change signal, thereby adjusting the input amount of air at the input end of the burner 1 to ensure sufficient combustion of natural gas and exhaust gas.

[0032] When the opening of the natural gas flow regulating valve 3 is reduced to closed, the PLC controller will close the natural gas solenoid valve 4, and then enter the stage of burning the exhaust gas alone. The PLC controller adjusts the opening of the air ratio regulating valve 9 according to the instantaneous temperature, exhaust gas pressure and flow signal, thereby controlling the input amount of air at the input end of the burner 1 to ensure sufficient combustion of the exhaust gas. If the natural gas solenoid valve 4 is closed, that is, the natural gas is stopped from entering the burner 1, and the instantaneous temperature is still greater than the set temperature, the PLC controller controls the exhaust gas solenoid valve 6 to close, the burner 1 stops burning, and the temperature is reduced.

[0033] Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A control system for an exhaust gas burner, characterized in that: The control system is suitable for a natural gas combustion stage alone, a mixed combustion of natural gas and exhaust gas stage, and an exhaust gas combustion stage performed sequentially. The control system includes a PLC controller, a burner, a temperature measuring device, a natural gas flow regulating valve, a natural gas flow transmitter, an exhaust gas solenoid valve, an exhaust gas pressure transmitter, and an exhaust gas flow transmitter. The output end of the burner is connected to the temperature measuring device. The input end of the burner is provided with a natural gas input end and an exhaust gas input end. The natural gas input end is connected to the output end of the natural gas flow regulating valve. The output end of the natural gas flow regulating valve is also connected to the natural gas flow transmitter. The exhaust gas input end is connected to the output end of the exhaust gas solenoid valve. The input end of the exhaust gas solenoid valve is connected to the exhaust gas pressure transmitter. The output end of the exhaust gas solenoid valve is connected to the exhaust gas flow transmitter. The PLC controller is electrically connected to the temperature measuring device, the natural gas flow regulating valve, the natural gas flow transmitter, the exhaust gas solenoid valve, the exhaust gas pressure transmitter, and the exhaust gas flow transmitter, respectively.

2. The exhaust gas burner control system according to claim 1, characterized in that: The control system also includes an air ratio regulating valve. The input end of the burner is also provided with an air input end. The air input end is connected to the output end of the air ratio regulating valve. The air ratio regulating valve is electrically connected to the PLC controller.

3. The control system of the exhaust gas burner according to claim 1, characterized in that: The control system further comprises an exhaust gas flow transmitter, which is connected to the output end of the exhaust gas solenoid valve and is electrically connected to the PLC controller.

4. A method for controlling an exhaust gas burner, characterized in that: The control method is applicable to the sequentially performed natural gas combustion stage, the mixed natural gas and exhaust gas combustion stage, and the exhaust gas combustion stage, and includes the following: (1) Natural gas combustion stage: The PLC controller receives the instantaneous temperature of the burner output end monitored by the temperature measuring device and compares it with the set temperature in the PLC controller. If the instantaneous temperature is less than the set temperature, the PLC controller starts the natural gas solenoid valve, and the natural gas enters the burner through the pipeline for combustion. The natural gas flow transmitter transmits the monitored natural gas flow signal to the PLC controller. The PLC controller adjusts the opening of the natural gas flow control valve according to the instantaneous temperature and the natural gas flow signal, thereby controlling the input amount of natural gas at the burner input end. At the same time, the PLC controller adjusts the opening of the air ratio control valve according to the natural gas flow signal, thereby controlling the input amount of air at the burner input end. (2) Mixed combustion of natural gas and exhaust gas: The PLC controller opens the exhaust gas solenoid valve, and the exhaust gas enters the burner for combustion. The exhaust gas pressure transmitter transmits the monitored exhaust gas pressure signal to the PLC controller, and the exhaust gas flow transmitter feeds back the monitored exhaust gas flow signal to the PLC controller. At this time, the PLC controller ensures that the opening of the air ratio control valve remains unchanged. The PLC controller reduces the opening of the natural gas flow control valve according to the exhaust gas pressure signal and the exhaust gas flow signal, thereby reducing the input amount of natural gas entering the burner. When the pressure and flow of the exhaust gas reach stability, the PLC controller adjusts the opening of the natural gas flow control valve according to the instantaneous temperature. If the instantaneous temperature is less than the set temperature, the opening of the natural gas flow control valve is increased. If the instantaneous temperature is greater than the set temperature, the opening of the natural gas flow control valve is decreased. At the same time, the PLC controller adjusts the opening of the air ratio control valve according to the instantaneous temperature, the natural gas flow change signal, and the exhaust gas pressure and flow change signal, thereby adjusting the input amount of air at the burner input end to ensure sufficient combustion of natural gas and exhaust gas. (3) Exhaust gas combustion stage: When the opening of the natural gas flow control valve is reduced to closed, the PLC controller closes the natural gas solenoid valve. The PLC controller adjusts the opening of the air ratio control valve according to the instantaneous temperature, exhaust gas pressure and flow change signal, thereby controlling the input amount of air at the burner input end to ensure sufficient combustion of the exhaust gas.

5. The control method of the exhaust gas burner according to claim 4, characterized in that: The PLC controller is provided with a set value for the exhaust gas pressure. The exhaust gas pressure transmitter transmits the monitored real-time pressure change signal of the exhaust gas to the PLC controller. When the real-time pressure of the exhaust gas is greater than the set pressure, the PLC controller opens the exhaust gas solenoid valve.

6. The control method of the exhaust gas burner according to claim 4, characterized in that: In the stage of burning exhaust gas alone, if the instantaneous temperature of the burner monitored by the temperature measuring device is greater than the set temperature, the PLC controller controls the exhaust gas solenoid valve to close, the burner stops burning, and performs a temperature reduction process.

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