Adaptive dry fog dust suppression system based on dust concentration and control method

Abstract

The application relates to the technical field of industrial dust treatment, and discloses a self-adaptive dry fog dust suppression system based on dust concentration and a control method, wherein the system comprises a dust concentration monitor configured to collect a dust concentration signal in real time; a PLC controller configured to receive the dust concentration signal output by the dust concentration monitor, calculate a concentration deviation based on a preset target dust concentration, and output a spray adjustment instruction after PID algorithm operation; a variable frequency air compressor configured to dynamically adjust air source pressure and flow after receiving the spray adjustment instruction; an electric control proportional adjustment valve configured to dynamically adjust water supply flow after receiving the spray adjustment instruction; and a double-fluid ultrasonic nozzle configured to generate dry fog through air-water mixing. The application can dynamically change the dry fog generation amount and water mist particle diameter, and realize precise dust suppression on demand.

Description

Technical Field

[0001] This invention relates to the field of industrial dust control technology, and in particular to an adaptive dry fog dust suppression system and control method based on dust concentration. Background Technology

[0002] In the transportation and handling of bulk materials, such as fuel transportation in thermal power plants, material transfer points, crushing workshops, and unloading rooms are the main sources of dust emission. Inhalable respirable dust not only worsens the on-site working environment but also needs to meet stringent environmental emission requirements. Dry fog dust suppression technology atomizes water into fine water mist particles, which collide with and agglomerate with dust particles to achieve sedimentation. It has a good capture effect on respirable dust and is currently a widely used mainstream technology in the field of dust control.

[0003] Currently, most dry fog dust suppression systems in the industry adopt an open-loop control mode. The system is only linked to the operating status of the conveying equipment. After the conveying equipment starts, it continuously sprays according to a preset fixed air source pressure and water supply flow rate until the equipment stops. This control mode has several technical defects: Firstly, the system lacks a real-time feedback mechanism for dust concentration, making it impossible to adjust the spray volume according to the actual dust intensity. When dealing with materials with low moisture content and high dust intensity, the spray volume is insufficient to suppress dust, easily leading to excessive emission concentrations. When dealing with materials with high moisture content and low dust intensity, the system still maintains full-load spraying, which unnecessarily increases the moisture content of the material, affecting the quality of the material itself and potentially causing problems such as blockage of the conveying channel. The contradiction between dust suppression effect and material humidification and energy consumption is prominent.

[0004] Secondly, the system has a fixed air-water ratio. When the air source pressure deviates due to factors such as water separation in the pipeline, changes in ambient temperature, and fluctuations in pipeline load, the actual air-water mixing ratio deviates from the design value. This will cause the water mist particles to increase significantly in size, lose their ability to capture fine respirable dust, and result in a significant decrease in dust suppression efficiency.

[0005] Third, fixed spray parameters cannot be adapted to different dust generation mechanisms. Dust generated under high belt speed conditions is mainly composed of large particles, while dust generated under positive pressure conditions during crushing operations is mainly composed of fine dust. The uniform atomization parameters do not have an equal capture efficiency for the two types of dust, making it difficult to achieve efficient treatment of dust of all particle sizes.

[0006] To address the aforementioned issues, various improvement approaches have been explored in this field: some solutions involve adding physical sealing structures to prevent dust from escaping, but such structures wear out rapidly under the continuous action of material impacting the airflow, resulting in high maintenance and replacement costs, and they can only prevent dust diffusion, failing to reduce dust concentration at the source; other solutions attempt to indirectly adjust spray parameters by detecting the material state, but such indirect detection methods cannot directly reflect the true changes in dust concentration, and the detection elements are prone to contamination and failure in a high-dust environment, making long-term stable operation impossible. Summary of the Invention

[0007] To address the contradiction between dust suppression effect and energy consumption / coal humidification, particle size mismatch caused by gas source fluctuations, and poor adaptability to different working conditions in existing technologies, this invention proposes an adaptive dry fog dust suppression system and control method based on dust concentration. This system can dynamically change the amount of dry fog generated and the diameter of water mist particles to achieve precise dust suppression on demand.

[0008] The technical solution adopted in this invention is as follows: An adaptive dry fog dust suppression system based on dust concentration includes: A dust concentration monitor is installed at dust-generating locations and configured to collect dust concentration signals in real time. The PLC controller is configured to receive the dust concentration signal output by the dust concentration monitor, calculate the concentration deviation based on the preset target dust concentration, and output the spray adjustment command after PID algorithm calculation. The variable frequency air compressor is configured to dynamically adjust the air source pressure and flow rate after receiving a spray adjustment command; An electronically controlled proportional regulating valve is connected in series in the water supply pipeline, and its control terminal is connected to the second control output terminal of the PLC controller. It is configured to dynamically adjust the water supply flow rate after receiving a spray adjustment command. The dual-fluid ultrasonic nozzle, with its air interface connected to the air outlet of the variable frequency air compressor and its water interface connected to the water outlet of the electronically controlled proportional regulating valve, is configured to generate dry fog through air-water mixing.

[0009] Furthermore, the system also includes a belt scale signal acquisition device, which is configured to acquire the instantaneous load signal and belt speed signal of the coal conveyor belt and transmit them to the PLC controller; The PLC controller has a built-in feedforward control module. The feedforward control module is configured to pre-increase the spray output according to the corresponding proportion of the load increment before responding to the dust concentration feedback when the increase in the load of the coal conveyor belt exceeds a preset threshold within a set time. The output power of the variable frequency air compressor and the opening of the electronically controlled proportional regulating valve are adjusted simultaneously.

[0010] Furthermore, an air pressure transmitter is installed on the air outlet pipeline of the variable frequency air compressor, and a water flow meter is installed on the water outlet pipeline of the electronically controlled proportional regulating valve. The signal output terminals of the air pressure transmitter and the water flow meter are both connected to the PLC controller. The PLC controller is also configured to calculate the actual air-to-water ratio based on the collected air pressure data and water flow data, compare the actual air-to-water ratio with the preset target air-to-water ratio, and when the deviation between the two exceeds the set threshold, finely adjust the opening of the electronically controlled proportional regulating valve to bring the air-to-water ratio back to the target range.

[0011] Furthermore, the PLC controller integrates a Smith prediction compensation module, which has a built-in prediction model for the lag characteristics of the spray settling process. The PLC controller is also configured to compensate for the pure lag element of the system through the Smith prediction compensation module during the execution of the PID algorithm, thereby correcting the spray adjustment command output by the PID calculation.

[0012] Furthermore, the system also includes an automatic dust suppressant dispensing module, which includes a dust suppressant storage tank, a metering dosing pump, and a static mixer; The inlet of the metering dosing pump is connected to the dust suppressant storage tank, and the outlet is connected to the water supply pipeline downstream of the electronically controlled proportional regulating valve. The control terminal is connected to the PLC controller. The metering dosing pump is configured to receive instructions from the PLC controller to quantitatively output dust suppressant. The static mixer is connected in series downstream of the dosing point in the water supply pipeline and is configured to uniformly mix the dust suppressant with the water supply and then deliver it to the dual-fluid ultrasonic nozzle. The PLC controller is also configured to start the metering pump to add dust suppressant to the water circuit when it detects that both the variable frequency air compressor and the electronically controlled proportional regulating valve have reached their maximum output state and the dust concentration has been continuously higher than the preset high limit threshold for a period of time exceeding the set value; and to shut down the metering pump when the dust concentration falls back to below the set threshold.

[0013] Furthermore, multiple dual-fluid ultrasonic nozzles are provided, and the multiple dual-fluid ultrasonic nozzles are divided into several independent control zones. Each zone's water branch pipe is equipped with an independent electrically controlled valve, and the control terminal of each electrically controlled valve is connected to the PLC controller. The PLC controller is also configured to selectively open the electrically controlled valves of the corresponding zone according to the concentration distribution of dust points, and deliver water and gas media to the corresponding area.

[0014] Furthermore, a compressed air purging curtain device is provided on the outside of the probe of the dust concentration monitor. The air inlet of the purging curtain device is connected to the air outlet branch of the variable frequency air compressor and is configured to output a continuous purging airflow along the probe surface to block the adhesion and deposition of dust particles.

[0015] Furthermore, the system also includes a temperature sensor and a heat tracing and insulation component. The heat tracing and insulation component is wrapped around the outside of the outdoor water supply pipeline, the electrically controlled proportional regulating valve, and the gas-water distribution component. The signal output terminal of the temperature sensor is connected to the PLC controller. The PLC controller is also configured to control the start and stop of the heat tracing and insulation components based on the ambient temperature and pipeline temperature collected by the temperature sensor, so as to maintain the temperature of the medium in the pipeline above the freezing point under low temperature conditions.

[0016] Furthermore, an air storage tank and a refrigerated dryer are installed in the air path between the outlet end of the variable frequency air compressor and the dual-fluid ultrasonic nozzle, and a water filter and a booster pump are installed in the water supply pipeline at the inlet end of the electronically controlled proportional regulating valve; the air source is delivered to the nozzle after being stabilized by the air storage tank and dried by the refrigerated dryer, and the water source is delivered to the electronically controlled proportional regulating valve after being filtered by the water filter and boosted by the booster pump.

[0017] An adaptive dry fog dust suppression control method based on dust concentration includes: Preset target dust concentration, air-to-water ratio, and PID control parameters; The dust concentration, instantaneous load and belt speed signals of the coal conveyor belt at the dust emission points are collected in real time and input into the PLC controller; The PLC controller calculates the dust concentration deviation and outputs spray adjustment instructions through PID calculation, synchronously adjusting the air source pressure and water supply flow, while finely adjusting the water supply according to the actual air-water ratio to maintain the target water mist particle size. When the load on the coal conveyor belt is detected to increase beyond the set threshold for a short period, the spray volume is increased in advance. When the air-water regulation reaches the maximum output and the dust concentration continues to exceed the standard, the dust suppressant injection is started.

[0018] The beneficial effects of this invention are as follows: 1. This invention constructs a complete closed-loop control circuit for sensing, decision-making, execution, and feedback by coordinating a dust concentration monitor, a PLC controller, a variable frequency air compressor, an electronically controlled proportional control valve, and a dual-fluid ultrasonic nozzle. The system can dynamically adjust the spray output intensity according to the real-time dust concentration at the site. When the dust concentration increases, it simultaneously increases the air source pressure and flow rate and the water supply flow rate to enhance the dust suppression effect; when the dust concentration decreases, it correspondingly reduces the output power. This ensures that the dust concentration at the dust-generating point is stably controlled within the target range, avoiding excessive emissions, and also avoids the waste of electricity and water resources caused by indiscriminate continuous spraying. At the same time, it reduces the additional humidification of materials, reduces the negative impact on material quality, and achieves a balance between dust suppression effect and operating cost.

[0019] 2. This invention significantly improves the system's adaptability and control stability by combining real-time air-to-water ratio feedback adjustment, belt load feedforward control, and hysteresis compensation algorithm. Dynamic fine-tuning of the air-to-water ratio can offset atomization effect deviations caused by fluctuations in air source pressure and changes in environmental parameters, stabilizing the particle size range of water mist particles and maintaining a consistently high efficiency in capturing respirable dust. Load feedforward control can increase the spray volume in advance when there is a sudden increase in material conveying volume, compensating for the lag between the spray's effectiveness and dust settling, and reducing peak dust concentration during sudden load changes. The hysteresis compensation algorithm optimizes the PID control process, avoiding concentration regulation oscillations caused by pure system hysteresis, and improving adjustment speed and control accuracy.

[0020] 3. The additional structures proposed in this invention, such as automatic dust suppressant dispensing, nozzle zone control, sensor air curtain protection, and low-temperature heating, further expand the system's applicable scenarios and operational reliability. Under extreme high dust conditions, automatic dust suppressant dispensing can reduce the surface tension of water mist through chemical additives, enhancing the wetting and capture effect on fine dust particles, and is only activated when the air-water regulation reaches its limit, controlling agent consumption; nozzle zone control allows for precise spraying of localized areas with concentrated dust, further reducing operating energy consumption; sensor air curtain protection reduces dust adhesion and contamination of the monitoring probe, ensuring the long-term accuracy of concentration monitoring data; and the low-temperature heating structure prevents pipeline freezing failures in low-temperature environments, enabling the system to operate stably in cold environments. The entire system can achieve fully automatic closed-loop operation, eliminating the need for frequent manual adjustments and effectively reducing the workload of on-site maintenance. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of an adaptive dry fog dust suppression system based on dust concentration, according to Embodiment 1 of the present invention.

[0022] Figure 2 This is a schematic diagram of an adaptive dry fog dust suppression method based on dust concentration, according to Embodiment 1 of the present invention. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments are now described. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention; that is, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0024] Example 1 like Figure 1As shown, the present embodiment provides an adaptive dry fog dust suppression system based on dust concentration, comprising a dust concentration monitor, a PLC controller, a variable-frequency air compressor, an electric proportional control valve, and a two-fluid ultrasonic nozzle, wherein: The dust concentration monitor is arranged at the dust emission point and configured to collect dust concentration signals in real time; The PLC controller is configured to receive the dust concentration signal output by the dust concentration monitor, calculate a concentration deviation based on a preset target dust concentration, and output a spray adjustment instruction after operation via a PID algorithm; The control end of the variable-frequency air compressor is connected to the first control output end of the PLC controller, and is configured to dynamically adjust the air source pressure and flow after receiving the spray adjustment instruction; The electric proportional control valve is connected in series in the water supply pipeline, and the control end thereof is connected to the second control output end of the PLC controller, and is configured to dynamically adjust the water supply flow after receiving the spray adjustment instruction; The air path interface of the two-fluid ultrasonic nozzle is communicated with the air outlet end of the variable-frequency air compressor, and the water path interface thereof is communicated with the water outlet end of the electric proportional control valve, and is configured to generate dry fog through gas-water mixing.

[0025] Preferably, the system further comprises a belt scale signal collector, and the PLC controller has a built-in feedforward control module. Specifically, the belt scale signal collector establishes a signal connection with the belt scale instrument matched with the coal conveyor belt, collects the instantaneous load and belt speed signals of the belt in real time, and transmits the two types of signals to the PLC controller synchronously; the feedforward control module of the PLC controller continuously monitors the change rate of the belt load, and when detecting that the increase amplitude of the belt load within a set time period exceeds a preset threshold, without waiting for the response of the dust concentration feedback signal, it directly calculates the spray increment according to the corresponding proportion of the load increment, synchronously increases the operating power of the variable-frequency air compressor and the opening of the electric proportional control valve, and increases the spray output in advance.

[0026] It should be noted that the feedforward control can effectively compensate for the hysteresis existing in the process from the spray action to dust settling, avoid the instant exceeding of the dust concentration limit when the belt load increases suddenly, improve the response speed of the system to load fluctuation, and keep the dust concentration at the dust emission point in a stable range all the time.

[0027] Preferably, an air pressure transmitter is installed on the outlet pipe of the variable frequency air compressor, and a water flow meter is installed on the outlet pipe of the electronically controlled proportional regulating valve. The signal output terminals of both are connected to the PLC controller. Specifically, the air pressure transmitter collects the compressed air pressure data delivered to the nozzle in real time, and the water flow meter collects the water supply flow data delivered to the nozzle in real time, and uploads the two sets of data to the PLC controller simultaneously. The PLC controller calculates the current actual air-water ratio based on the collected pressure and flow parameters, compares the actual air-water ratio with the preset target air-water ratio, and when the deviation exceeds the set threshold, it outputs a fine-tuning command to the electronically controlled proportional regulating valve to correct the water flow by adjusting the valve opening, so that the actual air-water ratio returns to the target range.

[0028] It should be noted that by adjusting the air-to-water ratio in real time, the particle size of the water mist can be kept within a suitable dust suppression range when the air source pressure fluctuates or environmental parameters change. This ensures the capture efficiency of respirable dust, avoids the loss of the ability to capture fine dust due to excessively large water mist particle size, and guarantees the stability of the dust suppression effect.

[0029] Preferably, the PLC controller integrates a Smith prediction and compensation module, which contains a built-in prediction model for the lag characteristics of the spray settling process. Specifically, during the PLC controller's execution of PID closed-loop calculations, the Smith prediction and compensation module, based on a preset system pure lag model, predicts the lag time from the spray's effect to the change in dust concentration, anticipates the concentration change trend corresponding to the adjustment action, and feeds the prediction results back to the PID calculation stage to correct the output spray adjustment command, adapting and adjusting the control parameters and output amplitude of the PID calculation.

[0030] It should be noted that Smith predictive compensation can effectively offset the adverse effects of pure system time delay on closed-loop control, allowing the PID controller to use higher regulation gain without causing system oscillation, shortening the response time of dust concentration regulation, and improving the stability and regulation accuracy of closed-loop control.

[0031] Preferably, the system further includes an automatic dust suppressant dispensing module, which consists of a dust suppressant storage tank, a metering pump, and a static mixer. Specifically, the dust suppressant storage tank stores the dust suppressant wetting agent. The inlet of the metering pump is connected to the dust suppressant storage tank, and the outlet is connected to the water supply pipeline downstream of the electronically controlled proportional control valve. The static mixer is connected in series in the water supply pipeline downstream of the dispensing point. The PLC controller monitors the operating status of the variable frequency air compressor and the opening of the electronically controlled proportional control valve in real time. When both reach their maximum output state and the dust concentration remains above the preset high threshold for a period exceeding a set value, the PLC controller outputs a start command to the metering pump, controlling the pump to inject the dust suppressant into the water supply pipeline according to a set ratio. The dust suppressant and water are fully mixed in the static mixer and then delivered to the dual-fluid ultrasonic nozzle. When the dust concentration falls below the set threshold, the PLC controller outputs a command to shut down the metering pump and stop the dust suppressant dispensing.

[0032] It should be noted that under extreme conditions of high dust concentration, adding dust suppressants can reduce the surface tension of water mist, improve the wetting and capture effect on fine respirable dust, and enhance dust suppression capabilities without increasing the amount of water sprayed. At the same time, once the concentration drops, the dosing should be stopped first to reduce the consumption of chemicals and control operating costs.

[0033] Preferably, multiple dual-fluid ultrasonic nozzles are provided, and the multiple dual-fluid ultrasonic nozzles are divided into several independent control zones. Each zone's water branch pipe is equipped with an independent electrically controlled valve, and the control terminal of each electrically controlled valve is connected to a PLC controller.

[0034] Specifically, based on the spatial distribution and dust generation characteristics of the dust sources, all dual-fluid ultrasonic nozzles are divided into multiple independent control zones. Each zone corresponds to a local dust area, and each zone's water branch pipe is equipped with an electrically controlled valve to independently control its on / off state. The PLC controller combines the dust concentration distribution data from multiple points to determine the area where dust is concentrated, and opens the electrically controlled valve of the corresponding zone to deliver water and air medium to the nozzles in that zone. Zones where no obvious dust occurs keep their valves closed.

[0035] It should be noted that nozzle zone control can achieve precise local dust suppression, avoid the waste of resources caused by continuous spraying in dust-free areas, further reduce water and energy consumption, and adapt to different dust-generating conditions in different locations, thereby improving the targeting of dust suppression.

[0036] Preferably, a compressed air purging curtain device is provided on the outside of the probe of the dust concentration monitor. Specifically, the purging curtain device is installed around the probe of the concentration monitor, and its air inlet is connected to the air outlet branch of the variable frequency air compressor to introduce clean compressed air. When the device is running, it outputs a continuous purging airflow outward along the probe surface, forming an air curtain barrier in front of the probe to prevent dust particles in the dusty area from approaching and adhering to the probe surface.

[0037] It should be noted that air curtain purging protection can prevent dust from adhering to the probe surface for a long time, which may cause monitoring data drift or sensor failure, maintain the accuracy and stability of concentration monitoring data, reduce the frequency of sensor cleaning and maintenance, and extend the service life of the equipment.

[0038] Preferably, the system further includes a temperature sensor and a heat tracing and insulation component, with the signal output of the temperature sensor connected to a PLC controller. Specifically, the heat tracing and insulation component covers the exterior of the outdoor water supply pipeline, the electrically controlled proportional regulating valve, and the air-water distribution component. The temperature sensor collects the ambient temperature and the internal temperature of the pipeline and components, respectively, and transmits the data to the PLC controller. Based on the collected temperature data, the PLC controller activates the heat tracing and insulation component to heat the system when the temperature is below a set threshold, and stops heating when the temperature rises back to the set upper limit, maintaining the temperature of the medium inside the pipeline and components above the freezing point. In the event of a long-term shutdown, the PLC controller can control the execution of a pipeline purging procedure, using compressed air to purge and drain any residual water from the pipeline.

[0039] It should be noted that the heat tracing and antifreeze solution can ensure the stable operation of the system in low-temperature environments, prevent the water in the pipelines and valves from freezing, which could cause equipment damage or prevent the system from starting normally, and expand the environmental applicability of the system.

[0040] Preferably, an air storage tank and a refrigerated dryer are installed in the air path between the outlet of the variable frequency air compressor and the dual-fluid ultrasonic nozzle, and a water filter and a booster pump are installed in the water supply pipeline at the inlet of the electronically controlled proportional regulating valve. Specifically, the compressed air output by the variable frequency air compressor first enters the air storage tank for pressure stabilization to eliminate fluctuations in the air source pressure. The stabilized compressed air is then passed into the refrigerated dryer for freeze drying to remove moisture and impurities from the air. The dried and clean compressed air is finally delivered to the dual-fluid ultrasonic nozzle. The external water source first passes through a water filter to remove particulate impurities from the water, and then is boosted by the booster pump before being delivered to the electronically controlled proportional regulating valve for flow regulation.

[0041] It should be noted that the air tank and refrigerated dryer can improve the quality and pressure stability of the air source, ensuring the consistency of the nozzle atomization effect; the water filter can prevent impurities from clogging the nozzles and proportional valves, and the booster water pump can stabilize the water supply pressure, improve the accuracy of flow regulation, and improve the overall reliability of system operation and the service life of equipment.

[0042] like Figure 2 As shown, this embodiment also provides an adaptive dry fog dust suppression control method based on dust concentration, including: Preset target dust concentration, air-to-water ratio, and PID control parameters; The dust concentration, instantaneous load and belt speed signals of the coal conveyor belt at the dust emission points are collected in real time and input into the PLC controller; The PLC controller calculates the dust concentration deviation and outputs spray adjustment instructions through PID calculation, synchronously adjusting the air source pressure and water supply flow, while finely adjusting the water supply according to the actual air-water ratio to maintain the target water mist particle size. When the load on the coal conveyor belt is detected to increase beyond the set threshold for a short period, the spray volume is increased in advance. When the air-water regulation reaches the maximum output and the dust concentration continues to exceed the standard, the dust suppressant injection is started.

[0043] Specifically, the target dust concentration, target air-to-water ratio range, and relevant PID control parameters are preset through the human-machine interface. During system operation, dust concentration data at dust-generating points and instantaneous load and belt speed data of the coal conveyor belt are collected in real time and transmitted to the PLC controller. The PLC controller calculates the deviation between the current dust concentration and the target concentration, outputs spray adjustment commands through PID calculation, and synchronously adjusts the air source pressure and flow rate of the variable frequency air compressor and the water supply flow rate of the electronically controlled proportional regulating valve. At the same time, it calculates the actual air-to-water ratio based on the real-time collected air pressure and water flow rate, and fine-tunes the water supply to maintain the target water mist particle size. During operation, the belt load change is continuously monitored. When the belt load increase exceeds the set threshold for a short period of time, the spray output is increased in advance. When both air and water regulation reach the maximum output and the dust concentration continues to exceed the standard, the dust suppressant is automatically injected to enhance the dust suppression effect.

[0044] It should be noted that this control method, through closed-loop feedback and multi-dimensional operating condition adaptation, can achieve precise dust suppression on demand, taking into account both dust suppression effect and operating energy consumption. It can also adapt to various operating conditions such as load fluctuation, air source fluctuation, and extreme high concentration, thereby improving the system's automation level and operating condition adaptability without the need for frequent manual intervention and adjustment.

[0045] Example 2 This embodiment is based on embodiment 1: This system was implemented at the No. 2 coal conveyor belt transfer point (1400mm belt width, 2.5m / s belt speed, rated coal conveying capacity 1200t / h) of a thermal power plant. The system was equipped with a GCG1000 electrostatic induction dust concentration sensor (measuring range 0.1~1000mg / m³), an S7-1200 PLC controller, a GA37VSD variable frequency air compressor (37kW), an SMC ITV3050 electro-proportional valve, and 12 SV-508 dual-fluid ultrasonic nozzles (arranged in a three-layer ring).

[0046] The preset target concentration C_target = 4 mg / m³, PID parameters: Kp = 1.2, Ti = 30 s, Td = 5 s, and the air-to-water ratio is set to 1:0.35.

[0047] Operating Procedure: After the system is powered on, the dust collector collects concentration data at 0.5-second intervals, the air compressor operates in standby mode at 30Hz, and the proportional valve maintains a 5% opening. When the belt conveyor starts and the flow rate exceeds 100 t / h, the system switches to automatic mode. Assuming an initial concentration C(t) = 12 mg / m³, a deviation e(t) = 8 mg / m³, and a PID output u(t) = 50%, this corresponds to an air compressor frequency of 40Hz and a proportional valve opening of 52.5%. After approximately 5 seconds of spraying, the concentration drops to 6 mg / m³, the deviation decreases, the output returns to normal, and the concentration eventually stabilizes at 4 ± 1 mg / m³. After the belt conveyor stops, the system returns to standby mode. Actual continuous operation for 72 hours showed stable dust concentration meeting standards, an average air compressor frequency of 38Hz, and a 24% energy saving rate.

[0048] Example 3 This embodiment is based on embodiment 2: Based on Example 2, a belt load feedforward control, Smith prediction compensation, and dust suppressant automatic dispensing module are added.

[0049] Feedforward control: When the belt load jumps from 600t / h to 1000t / h within 1 second, the PLC immediately increases the spray volume (the air compressor increases from 36Hz to 42Hz, and the proportional valve increases from 40% to 65%), so that the peak concentration drops from 18mg / m³ without feedforward to 8mg / m³, a reduction of 55%.

[0050] Smith's prediction: By establishing a prediction model with a lag time τ≈5 seconds, the PID proportional gain Kp can be increased from 1.2 to 1.8 without oscillation, and the settling time can be shortened from 15 seconds to 9 seconds.

[0051] Dust suppressant addition: When burning low-moisture lean coal (moisture content 5%~7%), if the system detects a concentration consistently higher than 15mg / m³ and both the air compressor and proportional valve are at full output, the metering dosing pump will automatically start, adding wetting agent at a ratio of 0.2%~0.5%. Comparative tests show that the capture efficiency of respirable dust increases from 65% for pure water dry fog to 92%.

[0052] Example 4 This embodiment is based on embodiment 1: For operating conditions with ambient temperatures below -20℃, electric heating tape (25W / m) and a 50mm insulation layer are installed on the exterior of outdoor water pipes, electrically controlled proportional valves, and water-air distribution boxes. A compressed air heater (2kW) is also installed at the outlet of the refrigerated dryer. A PT100 temperature sensor is used, and the PLC control logic is as follows: When the ambient temperature is <5℃, it enters the antifreeze mode: in standby mode, it periodically (every 30 seconds) opens the proportional valve to 10% opening degree and continues for 2 seconds to keep the water flowing in the pipeline.

[0053] The heat tracing cable is activated when the temperature inside the water-air distribution box is <5℃ and deactivated when the temperature is >15℃.

[0054] When the compressed air dew point temperature is more than 5°C lower than the ambient temperature, start the air heater to raise the air temperature to more than +5°C to prevent ice crystals from clogging the nozzle.

[0055] When the belt stops for more than 30 minutes and a long downtime is expected, perform the purging procedure: turn off the water pump, open the proportional valve to 100% and simultaneously purge with compressed air for 3 minutes to drain the remaining water from the pipeline.

[0056] Actual measurements showed that at an ambient temperature of -25℃, the internal temperature of the water vapor distribution box remained at 8~12℃, the system did not freeze, and the dust suppression effect was stable.

[0057] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

[0058] It should be noted that, for the sake of simplicity, the foregoing method embodiments are described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0059] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set", "install", and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a wired connection or a wireless connection.

Claims

1. An adaptive dry fog dust suppression system based on dust concentration, characterized in that, include: A dust concentration monitor is installed at dust-generating locations and configured to collect dust concentration signals in real time. The PLC controller is configured to receive the dust concentration signal output by the dust concentration monitor, calculate the concentration deviation based on the preset target dust concentration, and output the spray adjustment command after PID algorithm calculation. The variable frequency air compressor is configured to dynamically adjust the air source pressure and flow rate after receiving a spray adjustment command; An electronically controlled proportional regulating valve is connected in series in the water supply pipeline, and its control terminal is connected to the second control output terminal of the PLC controller. It is configured to dynamically adjust the water supply flow rate after receiving a spray adjustment command. The dual-fluid ultrasonic nozzle, with its air interface connected to the air outlet of the variable frequency air compressor and its water interface connected to the water outlet of the electronically controlled proportional regulating valve, is configured to generate dry fog through air-water mixing.

2. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, It also includes a belt scale signal acquisition device, which is configured to acquire the instantaneous load signal and belt speed signal of the coal conveyor belt and transmit them to the PLC controller; The PLC controller has a built-in feedforward control module. The feedforward control module is configured to pre-increase the spray output according to the corresponding proportion of the load increment before responding to the dust concentration feedback when the increase in the load of the coal conveyor belt exceeds a preset threshold within a set time. The output power of the variable frequency air compressor and the opening of the electronically controlled proportional regulating valve are adjusted simultaneously.

3. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, An air pressure transmitter is installed on the air outlet pipeline of the variable frequency air compressor, and a water flow meter is installed on the water outlet pipeline of the electronically controlled proportional regulating valve. The signal output terminals of the air pressure transmitter and the water flow meter are both connected to the PLC controller. The PLC controller is also configured to calculate the actual air-water ratio based on the collected air pressure data and water flow data, compare the actual air-water ratio with the preset target air-water ratio, and when the deviation between the two exceeds the set threshold, fine-tune the opening of the electronically controlled proportional regulating valve so that the air-water ratio returns to the target range.

4. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, The PLC controller integrates a Smith prediction and compensation module, which has a built-in prediction model for the hysteresis characteristics of the spray settling process. The PLC controller is also configured to compensate for the pure time delay of the system through the Smith prediction compensation module during the execution of the PID algorithm, thereby correcting the spray adjustment command output by the PID calculation.

5. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, It also includes an automatic dust suppressant dispensing module, which includes a dust suppressant storage tank, a metering dosing pump and a static mixer; The inlet of the metering dosing pump is connected to the dust suppressant storage tank, and the outlet is connected to the water supply pipeline downstream of the electronically controlled proportional regulating valve. The control terminal is connected to the PLC controller. The metering dosing pump is configured to receive instructions from the PLC controller to quantitatively output dust suppressant. The static mixer is connected in series downstream of the dosing point in the water supply pipeline and is configured to uniformly mix the dust suppressant with the water supply and then deliver it to the dual-fluid ultrasonic nozzle. The PLC controller is also configured to start the metering pump to add dust suppressant to the water circuit when it detects that both the variable frequency air compressor and the electronically controlled proportional regulating valve have reached their maximum output state and the dust concentration has been continuously higher than the preset high limit threshold for a period of time exceeding the set value; and to shut down the metering pump when the dust concentration falls back to below the set threshold.

6. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, The dual-fluid ultrasonic nozzle is provided in multiple ways, and the multiple dual-fluid ultrasonic nozzles are divided into several independent control zones. Each zone's water branch pipe is equipped with an independent electrically controlled valve, and the control terminal of each electrically controlled valve is connected to the PLC controller. The PLC controller is also configured to selectively open the electrically controlled valves of the corresponding zones according to the concentration distribution of dust points, and deliver water and gas media to the corresponding areas.

7. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, The dust concentration monitor is equipped with a compressed air purging curtain device on the outside of the probe. The air inlet of the purging curtain device is connected to the air outlet branch of the variable frequency air compressor and is configured to output a continuous purging airflow along the probe surface to prevent dust particles from adhering and depositing.

8. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, It also includes a temperature sensor and a heat tracing and insulation component. The heat tracing and insulation component is wrapped around the outside of the outdoor water supply pipeline, the electronically controlled proportional regulating valve and the gas-water distribution component. The signal output terminal of the temperature sensor is connected to the PLC controller. The PLC controller is also configured to control the start and stop of the heat tracing and insulation components based on the ambient temperature and pipeline temperature collected by the temperature sensor, so as to maintain the temperature of the medium in the pipeline above the freezing point under low temperature conditions.

9. The adaptive dry fog dust suppression system based on dust concentration according to claim 1, characterized in that, An air storage tank and a refrigerated dryer are installed in the air path between the outlet end of the variable frequency air compressor and the dual-fluid ultrasonic nozzle. A water filter and a booster pump are installed in the water supply pipeline at the inlet end of the electronically controlled proportional regulating valve. The air source is delivered to the nozzle after being stabilized by the air storage tank and dried by the refrigerated dryer. The water source is delivered to the electronically controlled proportional regulating valve after being filtered by the water filter and boosted by the booster pump.

10. An adaptive dry fog dust suppression control method based on dust concentration, characterized in that, include: Preset target dust concentration, air-to-water ratio, and PID control parameters; The dust concentration, instantaneous load and belt speed signals of the coal conveyor belt at the dust emission points are collected in real time and input into the PLC controller; The PLC controller calculates the dust concentration deviation and outputs spray adjustment instructions through PID calculation, synchronously adjusting the air source pressure and water supply flow, while finely adjusting the water supply according to the actual air-water ratio to maintain the target water mist particle size. When the load on the coal conveyor belt is detected to increase beyond the set threshold for a short period, the spray volume is increased in advance. When the air-water regulation reaches the maximum output and the dust concentration continues to exceed the standard, the dust suppressant injection is started.

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