A logic control method of a pneumatic ash conveying system

Abstract

This invention discloses a logic control method for a pneumatic ash conveying system. It is used to monitor and control particulate matter generated by a boiler during the pneumatic ash conveying process. In this process, hot compressed air is heated by an electric heater and then sent into the hopper pump through an ash hopper gasification pipe. This ensures the fluidity of the particulate matter in the ash hopper, facilitating smooth ash removal. Simultaneously, a make-up air valve automatically opens when the pressure in the ash conveying pipe gradually increases to a set opening pressure value, and automatically closes when the conveying pressure is lower than the opening pressure of the make-up air valve. This saves compressed air consumption, improves energy efficiency, reduces overload operation of pipelines and equipment, helps reduce the risk of equipment wear and damage, extends the system's service life, and reduces maintenance and replacement costs.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the pneumatic ash conveying control technology, in particular to a logic control method of a pneumatic ash conveying system. BACKGROUND

[0002] Due to the uncertainty of the coal source, the calorific value of the coal is different, when the high calorific value coal is burned, the compressed air amount needs to be reduced for conveying, when the compressed air pressure is too large, the energy consumption is increased, unnecessary energy waste is caused, and the energy consumption and operation cost in the industrial process are increased. When the compressed air pressure is too large, the instability of the pneumatic ash conveying system is easily caused. The high pressure can cause the violent stirring and impact of the particles in the pipeline, increase the friction resistance of the pipeline, and even cause the pipeline vibration and noise. Under the high pressure, the impact force of the particles on the inner wall of the pipeline is increased, which can cause the inner wall of the pipeline to be worn more seriously, and the service life of the equipment is shortened. The high compressed air pressure also causes a large pressure load on the valves, pipelines and connecting pieces and other equipment of the pneumatic ash conveying system, and the maintenance difficulty and frequency of the system are increased. SUMMARY

[0003] The present application provides a logic control method of a pneumatic ash conveying system, which reduces the overload operation of the pipeline and equipment, and reduces the wear and damage risk of the equipment.

[0004] The logic control method of the pneumatic ash conveying system provided by the embodiment of the present application specifically includes the following steps:

[0005] S1, opening the air valve for 10 seconds and then closing, opening the feeding valve, closing the air inlet valve, and the discharge valve is in a closed state at this time, then the solid particles generated by the electric precipitator enter the hopper, the feeding valve is opened, and the solid particles enter the bin pump from the hopper,

[0006] S2, starting the Roots blower, and the compressed air of the Roots blower enters the hopper,

[0007] S3, opening the electric heater, and the hot compressed air is sent into the bin pump through the hopper gasification pipeline, so that the solid particles are gasified and kept at a preset temperature,

[0008] S4, after the ash discharge condition from the bin pump is met, the air valve and the feeding valve are closed, the air inlet valve is opened, the discharge valve is opened to prepare for ash discharge, the voltage of the Roots blower is adjusted by using the PID algorithm, the ash in the hopper is fully fluidized, then the fluidized particles enter the ash conveying pipeline through the discharge valve, and are conveyed to the ash storage through the ash conveying pipeline,

[0009] S5, when the pressure in the ash conveying pipeline gradually increases to the opening pressure value of the air supplement valve, the air supplement valve automatically opens for air supplement, and the Roots blower reduces the voltage until the conveying pressure is less than the opening pressure of the air supplement valve, when the conveying pressure is less than the opening pressure of the air supplement valve, the air supplement valve is automatically closed,

[0010] S6, after the ash removal is completed, the inlet valve is closed for five seconds, and then the outlet valve is closed, and the PLC control system controls the next working cycle.

[0011] Optionally, the logic control method of the pneumatic ash conveying system further comprises: using a PID algorithm to adjust the voltage of the Roots blower, and the feedback control can be performed through the difference between the actual rotating speed and the set rotating speed of the Roots blower.

[0012] Δu(k)=K P [e(k)-e(k-1)]+K I e(k)+K D [e(k)-2e(k-1)-e(k-2)]

[0013] Wherein, Δu(k) refers to the difference voltage of the Roots blower that needs to be adjusted, e(k), e(k-1), e(k-2) represent the difference between the actual rotating speed and the set rotating speed of the first time, the second time and the third time, k P refers to the proportional value of the size of the output quantity to the size of the input error signal, k I refers to the integral value of the size of the output quantity to the size of the input error signal, k D refers to the differential value of the size of the output quantity to the size of the input error signal.

[0014] Optionally, before S1, the logic control method of the pneumatic ash conveying system further comprises:

[0015] S11, the solid particles enter the ash hopper, and the material level in the ash hopper is detected by the material level meter, if the set height is not reached, the solid particles continue to enter the ash hopper, if the material level in the ash hopper reaches the pre-set value, the PLC control system will automatically close the feeding valve to end the feeding.

[0016] Further, after S4, the logic control method of the pneumatic ash conveying system further comprises:

[0017] S41, the air pressure in the ash conveying pipeline is continuously detected by the pressure sensor during the ash removal stage, if the pressure in the ash conveying pipeline decreases to the lower limit value, it indicates that the conveying stage has been completed, at this time, the ash removal is stopped, if the pressure sensor in the ash conveying pipeline fails and the provided signal has no regularity, the ash removal is also stopped.

[0018] Further, after S41, the logic control method of the pneumatic ash conveying system further comprises:

[0019] S42, if the pressure value of the ash conveying pipeline reaches the pre-set upper limit value and lasts for more than two minutes, the PLC control system judges that the ash conveying pipeline has a blockage phenomenon, and then automatically alarms, closes the air inlet valve and opens the air outlet valve to slowly reduce the pressure of the ash conveying pipeline to achieve the effect of pressure reduction.

[0020] Further, after S42, the logic control method of the pneumatic ash conveying system further comprises:

[0021] S43, when the blockage phenomenon returns to normal, the PLC control system continues to control the ash discharge.

[0022] The logic control method of the pneumatic ash conveying system provided by the present application can heat the hot compressed air through an electric heater, and send the hot compressed air into the bin pump through the ash hopper gasification pipeline, which can ensure the flowability of the particulate matter in the ash hopper, and help to smoothly perform the ash removal process. The air supplement valve is automatically opened when the pressure in the ash conveying pipeline gradually rises to the set opening pressure value, and is automatically closed when the conveying pressure is less than the opening pressure of the air supplement valve, which saves the consumption of compressed air, improves the energy utilization efficiency, and reduces the overload operation of the pipeline and equipment. It helps to reduce the risk of equipment wear and damage, prolongs the service life of the system, and reduces maintenance and replacement costs. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a flow chart of a logic control method of a pneumatic ash conveying system provided by an embodiment of the present application;

[0024] Figure 2 is a flow chart of another logic control method of a pneumatic ash conveying system provided by an embodiment of the present application;

[0025] Figure 3 is a structural diagram of a logic control device of a pneumatic ash conveying system provided by an embodiment of the present application;

[0026] Figure 4 is a connection diagram of a pneumatic ash conveying system provided by an embodiment of the present application;

[0027] Figure 5 is another connection diagram of a pneumatic ash conveying system provided by an embodiment of the present application. DETAILED DESCRIPTION

[0028] The present application will be further described in detail below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, in order to facilitate description, only the parts related to the present application are shown in the drawings, but not all structures.

[0029] EMBODIMENT

[0030] The embodiment of the present application provides a logic control method of a pneumatic ash conveying system, which is used for monitoring and controlling particulate matters generated by a boiler in a pneumatic ash conveying process, and is realized by a logic control device of the pneumatic ash conveying system, as shown in Figure 1 and Figure 2 , and specifically comprises the following steps:

[0031] S1, opening the air valve for ten seconds and then closing the air valve, opening the feeding valve, closing the air inlet valve, and at this time, the discharging valve is closed, then the solid particulate matters generated by the electric dust collector enter the ash bucket, the feeding valve is opened, and the solid particulate matters enter the bin pump from the ash bucket.

[0032] S2, starting the Roots blower, and the compressed air of the Roots blower enters the ash bucket.

[0033] Specifically, the pressure sensor monitors the pressure value in the ash conveying pipeline in real time, if the pressure value in the ash conveying pipeline is lower than the preset pressure value of the ash conveying pipeline, the Roots blower continues to compress air into the ash bucket. If the pressure value in the ash conveying pipeline is higher than the preset pressure value of the ash conveying pipeline, it indicates that the ash discharging condition from the bin pump is met, the air valve and the feeding valve are closed, and the air inlet valve is opened.

[0034] S3, opening the electric heater, and the hot compressed air is sent into the bin pump through the ash bucket gasification pipeline, so that the solid particulate matters are gasified and kept at a preset temperature.

[0035] Specifically, the hot compressed air is heated by the electric heater, the hot compressed air is sent into the bin pump through the ash bucket gasification pipeline, and the solid particulate matters are gasified and kept at a preset temperature, so as to prevent the solid particulate matters from caking due to cold, which can ensure that the particulate matters in the ash bucket keep fluidity and help the ash discharging process to be carried out smoothly.

[0036] After the particulate matters in the ash bucket are heated, they are in a high-temperature state, and their fluidity and flow speed are improved. This helps the solid particulate matters to mix better with the gas in the conveying process, increases the suspension of the particulate matters, and improves the ash discharging effect. At the same time, the high-temperature state helps to better convey the particulate matters to the bin pump, preventing the solid particulate matters from accumulating and blocking in the pipeline. Keeping the preset temperature in the solid particulate matter gasification pipeline can provide a stable conveying environment and reduce the volatility and instability of the particulate matter flow state. This helps the stability and continuity of the system operation and reduces the risk of failure caused by temperature changes.

[0037] S4, after the ash discharging condition from the bin pump is met, the air valve and the feeding valve are closed, the air inlet valve is opened, the discharging valve is opened to prepare for ash discharging, the voltage of the Roots blower is adjusted using the PID algorithm, the ash in the ash bucket is fully fluidized, then the fluidized particulate matters enter the ash conveying pipeline through the discharging valve, and are conveyed to the ash storage along the ash conveying pipeline.

[0038] S5, when the pressure in the ash conveying pipeline gradually increases to the opening pressure value of the air supplement valve, the air supplement valve automatically opens for air supplement, and the Roots blower reduces the voltage until the conveying pressure is less than the opening pressure of the air supplement valve, and when the conveying pressure is less than the opening pressure of the air supplement valve, the air supplement valve is automatically closed.

[0039] S6, after the ash removal is completed, the inlet valve is closed for five seconds, and then the outlet valve is closed, and the PLC control system will control the next working cycle.

[0040] Further, the logic control method of the pneumatic ash conveying system further comprises: using a PID algorithm to adjust the voltage of the Roots blower, which can be feedback controlled by measuring the difference between the actual speed and the set speed of the Roots blower,

[0041] Δu(k)=K P [e(k)-e(k-1)]+K I e(k)+K D [e(k)-2e(k-1)-e(k-2)]

[0042] wherein Δu(k) refers to the difference voltage of the Roots blower that needs to be adjusted, e(k), e(k-1), e(k-2) represent the difference between the actual speed and the set speed of the first time, the second time and the third time, k P refers to the proportional value of the size of the output quantity to the size of the input error signal, k I refers to the integral value of the size of the output quantity to the size of the input error signal, k D refers to the differential value of the size of the output quantity to the size of the input error signal.

[0043] Further, before S1, the logic control method of the pneumatic ash conveying system further comprises:

[0044] S11, the solid particles enter the ash hopper, and the material level in the ash hopper is detected by the material level meter, if the set height is not reached, the solid particles continue to enter the ash hopper, and if the material level in the ash hopper reaches the pre-set value, the PLC control system will automatically close the feeding valve to end the feeding.

[0045] After S4, the logic control method of the pneumatic ash conveying system further comprises:

[0046] S41, the air pressure in the ash conveying pipeline is continuously detected by the pressure sensor during the ash removal stage, if the pressure in the ash conveying pipeline decreases to its lower limit value, it indicates that the conveying stage has been completed, at this time, the ash removal is stopped, if the pressure sensor in the ash conveying pipeline fails and the provided signal has no regularity, the ash removal is also stopped.

[0047] Further, after S41, the logic control method of the pneumatic ash conveying system further comprises:

[0048] S42, if the pressure value of the ash conveying pipeline reaches the pre-set upper limit value and lasts for more than two minutes, the PLC control system judges that the ash conveying pipeline has a blockage phenomenon, then automatically alarms, closes the air inlet valve, opens the air valve, and slowly reduces the pressure of the ash conveying pipeline to achieve the effect of pressure reduction;

[0049] Further, after S42, the logic control method of the pneumatic ash conveying system further comprises:

[0050] S43, when the blockage phenomenon returns to normal, the PLC control system continues to control the ash discharge.

[0051] The logic control method of the pneumatic ash conveying system of the embodiment is realized by a corresponding logic control device of the pneumatic ash conveying system, which is described in detail below. Figures 3-5 The logic control device of the pneumatic ash conveying system comprises a PLC control system, a level meter, a pressure sensor, a flow sensor, a first temperature sensor, a second temperature sensor, a display, a control button, a Roots blower, an electric precipitator, an electric heater, an air valve, a feeding valve, an air inlet valve, a gas supplement valve and a discharge valve,

[0052] The PLC control system is used for real-time monitoring and control of the operation of the system, and the running state of the pneumatic ash conveying system is monitored in real time through the level meter, the pressure sensor, the first temperature sensor, the second temperature sensor and the flow sensor, and the operation of the Roots blower, the electric precipitator, the electric heater, the air valve, the feeding valve, the air inlet valve, the gas supplement valve and the discharge valve can be controlled. The air valve is arranged in the ash bucket, the feeding valve is connected between the ash bucket and the bin pump, the air inlet valve, the gas supplement valve and the discharge valve are arranged in the bin pump, the electric precipitator is a device for removing dust particles in the gas, the electric precipitator makes the dust particles charged through the electric field, and collects and removes these charged particles through the electrode, the electric heater is used for heating the fluid in the pneumatic ash conveying system, and the Roots blower is used for generating air flow to push the solid particles to gasify and move in the conveying pipeline.

[0053] The level meter is installed in the ash bucket, and the level meter is used for measuring and monitoring the material level in the ash bucket,

[0054] The pressure sensor is installed in the ash conveying pipeline, and the pressure sensor is used for measuring the air pressure in the ash conveying pipeline. By obtaining the real-time pressure value, the PLC control system can adjust the speed of the blower and the air flow to maintain a suitable pressure range and ensure the normal operation of the system,

[0055] The first temperature sensor is installed in the bin pump for measuring the temperature of the air in the bin pump, and the second temperature sensor is installed in the ash bucket gasification pipeline for measuring the temperature of the air in the ash bucket gasification pipeline,

[0056] The flow sensor is installed in the ash conveying pipeline, and the flow sensor is used to measure the flow of particulate matter,

[0057] The display is used to provide real-time status information and parameter setting options of the system to the operator,

[0058] The control button is a physical button used to operate the pneumatic ash conveying system.

[0059] Further, the logic control device of the pneumatic ash conveying system further comprises an ash hopper, a bin pump, and an ash storage.

[0060] The ash hopper is used to collect and store the generated solid particulate matter, the bin pump is used to pump the solid particulate matter in the ash hopper to downstream processing equipment or the ash storage, and the ash storage is used to store a large amount of solid particulate matter for subsequent processing or transportation.

[0061] Further, the logic control device of the pneumatic ash conveying system further comprises an ash hopper gasification pipeline, an air inlet pipeline, and an ash conveying pipeline.

[0062] The compressed air heated by the electric heater is sent to the bin pump through the ash hopper gasification pipeline, the Roots blower is connected to the bin pump through the air inlet pipeline, the solid particulate matter in the bin pump is fully fluidized, and the fluidized particulate matter in the bin pump is conveyed to the ash storage through the ash conveying pipeline.

[0063] The logic control method of the pneumatic ash conveying system provided in the embodiment has the following beneficial effects:

[0064] Energy saving: By automatically controlling the opening and closing of the air supplement valve according to actual needs, unnecessary energy waste can be avoided. Only when the system needs additional compressed air will the air supplement valve be opened, and at other times the air supplement valve will be closed, saving the consumption of compressed air and improving energy utilization efficiency.

[0065] Improve system stability: By dynamically adjusting the opening and closing of the air supplement valve, the system can work in a relatively stable pressure range. When the conveying pressure is lower than the opening pressure of the air supplement valve, the air supplement valve is automatically closed to ensure that excessive supply of compressed air does not cause system overload or other problems. This can maintain the smooth operation of the system and reduce the instability and failure risk caused by pressure fluctuations.

[0066] Prolong the service life of the equipment: Since the air supplement valve can supplement air as needed, it reduces the overload operation of the pipeline and equipment. This helps to reduce the risk of wear and damage to the equipment, prolongs the service life of the system, and reduces maintenance and replacement costs.

[0067] Simplified operation and management: After adopting the logical control method, the system can realize automatic operation, reducing the need for manual intervention. The opening and closing of the air supply valve can be automatically judged and executed according to the pressure value, simplifying the operation and management process and reducing the possibility of human error.

[0068] Note that the above is only the preferred embodiment of the present application and the technical principle applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A logic control method for a pneumatic ash conveying system, characterized in that, Specifically, the following steps are included: S1, after opening the vent valve for ten seconds and then closing it, open the feed valve while simultaneously closing the vent valve. At this time, the discharge valve is closed. Then, the solid particles generated by the electrostatic precipitator enter the ash hopper. Open the feed valve, and the solid particles enter the silo pump from the ash hopper. S2, start the Roots blower. The Roots blower compresses air and enters the ash hopper. S3: Turn on the electric heater. Hot compressed air is sent into the hopper pump through the ash hopper gasification pipe, causing the solid particles to vaporize and maintain the preset temperature. S4: After the conditions for ash discharge from the silo pump are met, close the vent valve and feed valve, open the inlet valve, and open the discharge valve to prepare for ash discharge. Use the PID algorithm to adjust the voltage of the Roots blower. The ash in the ash hopper is fully fluidized. Then, the fluidized particles will enter the ash conveying pipeline through the discharge valve and be transported to the ash silo along the ash conveying pipeline. S5, when the pressure inside the ash conveying pipeline gradually rises to the opening pressure value of the air replenishment valve, the air replenishment valve automatically opens to replenish air, and the Roots blower reduces the voltage until the conveying pressure is lower than the opening pressure of the air replenishment valve. When the conveying pressure is lower than the opening pressure of the air replenishment valve, the air replenishment valve automatically closes. S6, after ash removal is completed, close the inlet valve for five seconds, then close the outlet valve. The PLC control system will then initiate the next work cycle. This also includes: using a PID algorithm to adjust the voltage of the Roots blower; feedback control can be achieved by measuring the difference between the actual speed and the set speed of the Roots blower. ； in, This refers to the differential voltage that needs to be adjusted for the Roots blower. e ( k ), e ( k- 1), e ( k- 2) represents the difference between the actual rotational speed and the set rotational speed for the 1st, 2nd, and 3rd tests. k P This refers to the fact that the magnitude of the output quantity is proportional to the magnitude of the input error signal. k I This refers to the integral of the output quantity with respect to the input error signal. k D This refers to the difference between the magnitude of the output quantity and the input error signal; Following S4, it also includes: S41, during the ash discharge stage, the air pressure in the ash conveying pipeline is continuously detected by a pressure sensor. If the pressure in the ash conveying pipeline drops to its lower limit, it indicates that the conveying stage has been completed, and ash discharge will stop. If the pressure sensor in the ash conveying pipeline malfunctions and provides an irregular signal, ash discharge will also stop.

2. The logic control method for the pneumatic ash conveying system according to claim 1, characterized in that, Before S1, it also includes: S11, the solid particles entering the ash hopper are detected by the level gauge. If the set height is not reached, the solid particles continue to enter the ash hopper. If the level in the ash hopper reaches the preset value, the PLC control system will automatically close the feed valve to end the feeding.

3. The logic control method for the pneumatic ash conveying system according to claim 2, characterized in that, Following S41, it also includes: S42. If the pressure value of the ash conveying pipeline reaches the preset upper limit value and lasts for more than two minutes, the PLC control system will determine that the ash conveying pipeline is blocked, and then automatically alarm. At the same time, the air inlet valve will be closed and the air vent valve will be opened, so that the pressure of the ash conveying pipeline will slowly decrease to achieve the effect of pressure reduction.

4. The logic control method for the pneumatic ash conveying system according to claim 3, characterized in that, Following S42, it also includes: S43, once the pipe blockage is resolved, the PLC control system continues to control the ash discharge.

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