Method for reducing abrasion of pneumatic ash conveying pipeline and optimizing energy consumption

Abstract

The invention discloses a method for reducing abrasion and optimizing energy consumption of a pneumatic ash conveying pipeline, and relates to the field of fluid conveying and powder engineering. According to the method, a pure pneumatic diaphragm type pressure sensing unit is arranged at the key position of the conveying pipeline, pressure data are collected in real time, and feature intervals are divided to recognize the normal state, the early warning state or the blocking state; when blockage early warning is judged, the pilot-operated type self-induction mechanism drives the anti-blocking valve to be opened, lateral jet flow is introduced to assist airflow to disturb sediment materials, and the suspension conveying state is rebuilt; the pilot mechanism is not provided with an electronic element and is directly triggered to act by virtue of air pressure difference, and the response time is less than 0.2 second; the system also supports low-pressure pressure-maintaining scouring, main gas source pressure dynamic down-regulation and multi-branch independent cooperative operation. Zero-delay automatic blocking prevention can be achieved, the conveying pressure is reduced to 0.35 MPa or below, the gas consumption of unit materials is reduced by 40% or above, the service life of a pipe valve is prolonged to 2.3 times of the original service life, and the reliability and energy efficiency of a system are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of fluid transport and powder engineering, and in particular to a method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines. Background Technology

[0002] Pneumatic ash conveying, as an important method for dense-phase conveying of powdery materials, is widely used in the ash removal systems of thermal power plants. It utilizes compressed gas to propel ash particles along the flow direction within a closed pipeline, achieving efficient, continuous, or intermittent conveying. Based on the principle of fluidization, this technology boasts advantages such as simple structure, flexible operation, multi-directional arrangement, and material handling capabilities, making it the mainstream solution for current power plant ash and slag conveying systems. Among these systems, silo pumps, with their ability to stably convey high-concentration fly ash under high pressure, are widely adopted as the core equipment in pneumatic ash conveying. Their operation encompasses four stages: feeding, pressurization, conveying, and purging, forming a periodic, discontinuous operation mode.

[0003] Among them, the pilot-operated embolized pneumatic ash conveying system, as a novel technological approach aimed at improving conveying stability and energy efficiency, focuses on achieving full-pipe, low-speed conveying under high ash-to-gas ratio conditions by dynamically controlling the ash-gas mixing state and pressure distribution within the pipe. The core of this system lies in identifying the operating status based on the pressure characteristics throughout the conveying process and triggering the intervention of an auxiliary gas source accordingly to maintain uniform material propulsion within the pipe and suppress localized deposition. Compared to traditional silo pump systems that rely on fixed gas supply strategies and empirical operating parameters, this pressure feedback-based adaptive control mechanism can theoretically significantly reduce energy consumption, decrease wear, and improve system reliability.

[0004] However, existing silo-type pump ash conveying systems still face multiple technical bottlenecks in actual operation: insufficient air pressure or oil and water content can easily lead to an imbalance in the ash-to-air ratio, causing high-concentration blockages; settled ash and unburned carbon particles, due to their large size and poor flowability, are prone to depositing and forming blockages at bends or horizontal sections; and malfunctions in the air replenishment system directly disrupt the uniform mixing of ash and gas, exacerbating sudden increases in local resistance. More critically, traditional systems lack the ability to accurately determine the conveying status (such as normal flow, critical blockage, and complete blockage) in real time, making proactive intervention in the early stages of blockage impossible. They often rely on post-blockage clearing or manual adjustments, severely impacting unit safety and operational efficiency. Furthermore, existing anti-blockage measures largely rely on electrical sensors and control loops, which not only increase system complexity and potential failure points but also make it difficult to operate stably for extended periods in high-temperature, high-dust environments. Summary of the Invention

[0005] The purpose of this invention is to provide a method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines, in order to solve the problems of frequent blockages, severe pipeline wear, and excessive energy consumption caused by imbalance in the ash-to-air ratio, lack of real-time status judgment, and reliance on electrical control in traditional silo pump ash conveying systems.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines includes the following specific steps:

[0008] Step S1: Monitor the real-time pressure changes in the main conveying pipeline of the pneumatic ash conveying system. Through pressure sensing units set at key locations at the beginning, middle and end of the conveying process, pressure data is continuously collected throughout the entire conveying process. The pressure sensing unit adopts a pure pneumatic diaphragm structure, and its output signal is the amount of air pressure change, which is used to characterize the pressure characteristics of the current conveying stage, including pressurization at the start of conveying, pressure stabilization during normal flow, increase in local resistance and pressurization before blockage.

[0009] Step S2: Identify the conveying operation status based on the pressure change characteristics, divide the pressure curve into multiple characteristic intervals, determine the normal conveying state when the pressure rise rate is lower than the first preset threshold and remains in the stable interval, determine the blockage warning state when the pressure continues to rise and exceeds the second preset threshold but does not reach the limit pressure, determine the complete blockage state when the pressure rapidly rises to the third preset threshold and remains at a high level, and determine the complete blockage state when the pressure is completely blocked. Each preset threshold is calibrated according to historical operating data and material characteristics to form a fixed pneumatic feedback setpoint.

[0010] Step S3: When the blockage warning state is determined, the auxiliary gas supply action is triggered. By opening the anti-blockage valve set upstream of the blockage-prone area, the auxiliary airflow is introduced into the main pipeline. The auxiliary airflow is injected in the form of a lateral jet to disturb the deposited material and rebuild the uniform mixing state of ash and gas, so that the fly ash that has begun to accumulate can re-enter the suspension propulsion mode, thereby inhibiting the development of blockage.

[0011] Step S4: The opening of the anti-blocking valve is driven by a pilot-operated self-sensing mechanism. This mechanism receives the air pressure signal from the pressure sensing unit in step S1. When the signal reaches the pneumatic threshold of the corresponding blockage warning state, it directly pushes the valve core to move, opens the ventilation channel, and achieves zero-delay response. The pilot-operated self-sensing mechanism has no electronic components or electromagnetic parts inside and relies entirely on the air pressure difference to drive the mechanical valve group to move.

[0012] Step S5: After the auxiliary gas supply is completed, if the pressure returns to the normal delivery range, close the anti-blockage valve and continue the main delivery process; if the pressure is still high, it is determined that the main pipeline is seriously blocked, and the purging procedure is started. High-pressure gas pulses are used to reverse-impact the blocked section until the pressure drops, and then the normal delivery cycle is restarted. The whole process does not require human intervention or external controller participation in decision-making.

[0013] In step S1, the pressure sensing unit is arranged at the first monitoring point 0.5 meters away from the outlet of the silo pump, the second monitoring point 2 meters before the bend in the middle section of the horizontal pipe, and the third monitoring point at the bottom of the vertical riser pipe. Each monitoring point is equipped with a high-temperature and corrosion-resistant metal diaphragm sensor with a response frequency of not less than 10Hz, which can accurately capture the pressure transient process and transmit the output gas signal to the pilot control module through the pressure guide pipe.

[0014] In step S2, each preset threshold is determined through on-site debugging. The first preset threshold is set to ±10% of the average delivery pressure, the second preset threshold is set to 1.3 times the average pressure, and the third preset threshold is set to 1.8 times the average pressure. All thresholds are fixed in the pilot mechanism by a gas chamber pressure setting method to avoid environmental adaptability problems caused by software programming or digital settings.

[0015] In step S3, anti-blocking valves are installed every 15 meters in the horizontal straight pipe section, 3 meters before the 90-degree bend, and 5 meters upstream of the reducer. Each anti-blocking valve is connected to an independent auxiliary air source branch. The branch inlet is equipped with a throttling orifice plate to control the auxiliary air flow rate to 8% to 12% of the main air flow rate, ensuring that the material can be effectively disturbed without disrupting the overall conveying momentum balance.

[0016] In step S3, the nozzle angle of the lateral jet is set to form a 30-degree angle with the axis of the main pipe, the nozzle diameter is 6 mm, and three nozzles are evenly distributed along the circumference to form a spiral turbulent airflow field, which enhances the entrainment effect on ash particles in the low-speed zone near the pipe wall and prevents boundary layer deposition.

[0017] In step S4, the pilot-operated self-sensing mechanism includes a sensitive chamber, a comparison diaphragm, a transmission push rod, and an actuation valve core. When the air pressure in the sensitive chamber reaches the set value, the diaphragm is displaced and directly pushes open the main valve port through the push rod, opening the auxiliary air supply passage. The action response time of this mechanism is less than 0.2 seconds, and the reset relies on the combined action of the built-in spring and the downstream back pressure.

[0018] In step S4, the set pressure of the pilot-operated self-sensing mechanism can be adjusted offline by replacing springs of different stiffness or adjusting the pre-compression amount to adapt to the operating requirements under different ash quality, conveying distance and pipe diameter conditions. The adjustment range covers 0.2MPa to 0.6MPa.

[0019] The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines also includes: adding a low-pressure holding stage after the main pipeline conveying is completed, maintaining the residual pressure in the pipeline between 0.1MPa and 0.15MPa for 30 seconds, using the residual airflow to slowly flush the pipe wall, remove the attached ash, and reduce the static friction resistance when the next conveying starts.

[0020] The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines also includes: the main conveying gas source pressure is dynamically adjusted according to the maximum instantaneous pressure in the current conveying cycle. If the anti-blocking action is not triggered for three consecutive cycles, the starting pressure of the next cycle is automatically reduced by 0.05MPa, down to a minimum of 0.35MPa, to achieve on-demand gas supply and avoid energy waste caused by excessive pressurization.

[0021] The pneumatic ash conveying pipeline wear reduction and energy consumption optimization method is applied to dense phase full-pipe conveying conditions with an ash-to-gas ratio greater than 35:1. The conveying velocity is controlled within the range of 6m / s to 10m / s, and the single conveying frequency does not exceed 6 times per hour. The pipeline material is wear-resistant alloy steel, and the wall thickness is increased to 1.5 times that of the conventional design. Combined with the low-speed and stable pressure conveying characteristics of this invention, the life of the pipe valve is extended to more than 2.3 times that of the original system.

[0022] The auxiliary air source shares the same compressed air system as the main air source, but passes through an independent filter and pressure reducing device before entering the anti-blocking valve to ensure that the air source is clean and dry with a dew point temperature below -20°C, preventing moisture condensation from causing ash blocks to stick together.

[0023] The cleaning procedure uses intermittent high-pressure pulses, each pulse lasting 2 seconds with a 5-second interval, and can be executed a maximum of 3 times. If the blockage is still not cleared, an on-site audible and visual alarm will be issued to prompt manual inspection and avoid unnecessary gas consumption.

[0024] The pneumatic ash conveying pipeline wear reduction and energy consumption optimization method supports the coordinated operation of multi-branch ash conveying pipeline networks. Each branch pipeline is equipped with an independent pilot-operated self-sensing anti-blocking unit, which does not interact with each other and acts independently based on local pressure sensing, so as to avoid the abnormality of one branch affecting the normal operation of other lines.

[0025] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0026] This invention establishes a pressure sensing and response mechanism based on pure pneumatic logic, enabling fully automatic, zero-delay intervention against blockage risks during pneumatic ash conveying. This completely eliminates the dependence on external power and complex control systems, greatly improving the reliability and safety of the system in harsh industrial environments.

[0027] This invention accurately identifies pressure change characteristics and immediately activates auxiliary gas supply, eliminating blockages before they form and achieving truly "blockage-free" stable delivery. Since frequent start-stop or high-pressure unblocking is unnecessary, the main delivery pressure can remain stable below 0.35MPa for a long time, and the delivery velocity is reduced to an economical range of 6m / s to 10m / s. Combined with a high ash-to-gas ratio full-pipe delivery mode, the gas consumption per unit material delivery is reduced by more than 40% compared to traditional systems, and the system's power saving rate reaches 35%.

[0028] This invention significantly reduces the impact and friction of dust particles on elbows, valves, and the inner walls of pipes through low-speed and low-pressure operation, resulting in minimal wear on pipes and valves and extending their service life to 2.3 times the original level. Maintenance costs are also greatly reduced. The entire system has a simple structure, requiring only the installation of pilot-operated self-induction anti-blocking valves on the existing pipelines for modification. The construction period is short, and the investment payback period is less than 18 months. It is suitable for various power plant electrostatic precipitators, bag filters, and other pneumatic conveying scenarios for powdery materials, and has broad prospects for promotion and application. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall technical solution architecture of the method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines proposed in this invention;

[0030] Figure 2 This is a schematic diagram of the core principle framework of the self-induction pilot mechanism based on pure pneumatic logic in this invention. Detailed Implementation

[0031] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present invention and not to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0032] Example 1

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0034] Currently, pneumatic ash conveying, as an important method for dense-phase conveying of powdery materials, is widely used in the ash removal systems of thermal power plants. It utilizes compressed gas to propel ash particles along the flow direction within a closed pipeline, achieving efficient, continuous, or intermittent conveying. Based on the principle of fluidization, this technology boasts advantages such as simple structure, flexible operation, multi-directional arrangement, and material handling capabilities, making it the mainstream solution for ash and slag conveying systems in power plants. Among these, silo pumps, with their ability to stably convey high-concentration fly ash under high pressure, are widely adopted as the core equipment in pneumatic ash conveying. Their operation encompasses four stages: feeding, pressurization, conveying, and purging, forming a periodic, discontinuous operation mode. Pilot-operated embolized pneumatic ash conveying systems, as a new technological approach aimed at improving conveying stability and energy efficiency, focus on achieving full-pipe, low-speed conveying under high ash-to-gas ratio conditions by dynamically controlling the ash-gas mixing state and the pressure distribution within the pipe. The core of this system lies in identifying the operating state based on the pressure characteristics throughout the conveying process and triggering the intervention of an auxiliary gas source to maintain uniform material propulsion within the pipe and suppress localized deposition. Compared to traditional silo pump systems that rely on fixed air supply strategies and empirical operating parameters, this type of pressure feedback-based adaptive control mechanism can theoretically significantly reduce energy consumption, wear, and improve system reliability. However, existing silo pump ash conveying systems still face multiple technical bottlenecks in actual operation: insufficient air source pressure or oil and water contamination can easily lead to an imbalance in the ash-to-air ratio, causing high-concentration blockages; settled ash and unburned carbon particles, due to their large size and poor flowability, are prone to depositing and clogging at bends or horizontal sections; and malfunctions in the air supply system directly disrupt the uniform mixing of ash and air, exacerbating sudden increases in local resistance. More critically, traditional systems lack the ability to accurately determine the conveying status (such as normal flow, critical blockage, and complete blockage) in real time, making proactive intervention in the early stages of blockage impossible. They often rely on post-blockage clearing or manual adjustments, severely impacting unit safety and operating efficiency. Furthermore, existing anti-blockage measures largely rely on electrical sensors and control loops, which not only increase system complexity and potential failure points but also make it difficult to operate stably for extended periods in high-temperature and high-dust environments. Therefore, there is an urgent need for a self-sensing anti-clogging mechanism that can automatically detect abnormal pressure within the pipeline and immediately activate booster gas supply without external electrical control, relying solely on pneumatic logic, to simultaneously achieve blockage-free, low-wear, and high-efficiency operation in the ash conveying process. To address the aforementioned technical problems, this invention proposes a self-sensing pilot mechanism based entirely on pneumatic logic to automatically sense and respond to the pressure state within the ash conveying pipeline. This allows for dynamic adjustment of the gas supply strategy without external electrical control, fundamentally eliminating the risk of blockage, while simultaneously reducing conveying pressure and flow rate, significantly reducing pipeline wear and improving energy efficiency. This mechanism is applied to a method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines.

[0035] refer to Figure 1The schematic diagram of the overall technical solution for a method to mitigate wear and optimize energy consumption in pneumatic ash conveying pipelines proposed in this invention clearly illustrates the connection relationships and signal transmission paths between the main conveying pipeline, the silo pump, multiple pressure sensing units, the pilot-operated self-sensing mechanism, the anti-clogging valve, and the auxiliary air source branch. (Reference) Figure 2 The schematic diagram of the core principle framework of the self-sensing pilot mechanism based on pure pneumatic logic in this invention further reveals how the core components such as the sensitive chamber, the comparison diaphragm, the transmission push rod and the actuator valve core work together to directly convert the pressure signal into mechanical action, thereby driving the anti-blocking valve to open.

[0036] Step S1: Monitor the real-time pressure changes in the main conveying pipeline of the pneumatic ash conveying system. Pressure data throughout the entire conveying process is continuously collected by pressure sensing units set at key locations at the beginning, middle and end of the conveying process. The pressure sensing unit adopts a pure pneumatic diaphragm structure, and its output signal is the amount of air pressure change, which is used to characterize the pressure characteristics of the current conveying stage, including pressurization at the start of conveying, normal flow stabilization, local resistance increase and pre-blockage pressurization.

[0037] Specifically, pressure sensing units are located at the first monitoring point 0.5 meters from the outlet of the silo pump, the second monitoring point 2 meters before the bend in the middle section of the horizontal pipe, and the third monitoring point at the bottom of the vertical riser pipe. Each monitoring point is equipped with a high-temperature and corrosion-resistant metal diaphragm sensor with a response frequency of not less than 10Hz, which can accurately capture the pressure transient process. The output gas signal is transmitted to the pilot control module through the pressure guide pipe. The first monitoring point is used to capture the rapid pressure rise characteristics caused by the pressurization of the silo pump in the initial stage of conveying. The pressure peak and its rise slope in this stage are the primary basis for judging whether the ash-to-gas ratio is reasonable. The second monitoring point is located in the middle section of the horizontal pipe, adjacent to the 90-degree bend. This area is a high-incidence area for centrifugal sedimentation of materials due to inertia. The pressure fluctuation here can sensitively reflect the material accumulation trend and local resistance changes. The third monitoring point is located at the bottom of the vertical riser pipe. This position bears the cumulative effect of the conveying resistance of the entire horizontal pipe section. Its pressure value is a key indicator for assessing the overall load and blockage risk of the system. All pressure sensing units are made of 316L stainless steel with an internal diaphragm thickness of 0.3 mm and an effective sensing area of ​​80 square millimeters. The linearity is better than 0.5% within the 0 to 1.0 MPa range. The output air pressure signal is led to the corresponding pilot-operated self-sensing mechanism in a lossless manner through a stainless steel pressure guide tube with an inner diameter of 4 mm, ensuring the real-time performance and fidelity of signal transmission and avoiding attenuation or distortion of electrical signals in strong electromagnetic interference environments.

[0038] Step S2: Identify the conveying operation status based on pressure change characteristics, divide the pressure curve into multiple characteristic intervals, determine the normal conveying state when the pressure rise rate is lower than the first preset threshold and remains in the stable range, determine the blockage warning state when the pressure continues to rise and exceeds the second preset threshold but does not reach the limit pressure, determine the complete blockage state when the pressure rapidly rises to the third preset threshold and remains at a high level, and determine the complete blockage state when the pressure is completely blocked. Each preset threshold is calibrated according to historical operating data and material characteristics to form a fixed pneumatic feedback setpoint.

[0039] Specifically, each preset threshold is determined through on-site debugging. The first preset threshold is set to ±10% of the average conveying pressure, the second preset threshold is set to 1.3 times the average pressure, and the third preset threshold is set to 1.8 times the average pressure. All thresholds are fixed in the pilot mechanism using a gas chamber pressure-controlled method to avoid environmental adaptability issues caused by software programming or digital settings. Under normal conveying conditions, the system pressure fluctuates slightly within the set operating range. For example, at a reference pressure of 0.35 MPa, the fluctuation range is limited to 0.315 MPa to 0.385 MPa, and the pressure change rate is less than 0.02 MPa / s. This indicates that the ash and gas are mixed uniformly, and the material moves forward in a stable plunger or dune flow pattern. Once a monitoring point detects a continuous rise in pressure and exceeds 0.455 MPa (i.e., 1.3 times 0.35 MPa), the system enters a blockage warning state. This pressure value corresponds to the critical point where the material begins to form a dense layer near the pipe wall, and the flow resistance increases significantly. If the pressure continues to rise uncontrollably and reaches 0.63 MPa (1.8 times 0.35 MPa) without showing any downward trend within 5 seconds, it is considered a complete blockage. At this point, the material has formed a rigid blockage, and conventional conveying airflow cannot penetrate it. These thresholds are not fixed but are determined through a calibration process: after the system is initially put into operation or after the main material is changed, several standard conveying cycles are performed, and the pressure data at each monitoring point under normal conditions are recorded. The arithmetic mean of these data is calculated to obtain a baseline pressure value, and then three thresholds are generated proportionally. These thresholds are then mechanically "written" into the physical structure of the pilot mechanism, for example, by adjusting the spring preload or changing the effective volume of the feedback chamber, thereby forming unalterable hardware setpoints and ensuring the robustness of the system under extreme operating conditions.

[0040] Step S3: When the blockage warning state is determined, the auxiliary gas supply action is triggered. By opening the anti-blockage valve set upstream of the blockage-prone area, the auxiliary airflow is introduced into the main pipeline. The auxiliary airflow is injected in the form of a lateral jet to disturb the deposited material and rebuild the uniform mixing state of ash and gas, so that the fly ash that has begun to accumulate can re-enter the suspension propulsion mode, thereby inhibiting the development of blockage.

[0041] Specifically, anti-clogging valves are installed every 15 meters in horizontal straight pipe sections, 3 meters before 90-degree bends, and 5 meters upstream of reducers. Each anti-clogging valve is connected to an independent auxiliary air source branch, with a throttling orifice plate at the branch inlet to control the auxiliary air flow rate to 8% to 12% of the main air flow, ensuring effective material disturbance without disrupting the overall conveying momentum balance. The nozzle angle of the lateral jet is set at a 30-degree angle to the axis of the main pipe, with a nozzle diameter of 6 mm. Three nozzles are evenly distributed around the circumference, forming a spiral turbulent airflow field to enhance the entrainment of dust particles in the low-velocity zone near the pipe wall and prevent boundary layer deposition. Taking a 90-degree bend as an example, after the anti-clogging valve installed 3 meters upstream is activated, the auxiliary airflow is injected into the main pipe at a high speed at a 30-degree angle through three 6 mm nozzles evenly distributed at 120 degrees. This geometric layout generates a synthetic airflow with a significant tangential component, forming a rotating low-pressure vortex core in front of the bend inlet. This vortex core exerts a strong shearing effect on the pipe wall boundary layer, re-entraining coarse particles that have already begun to settle back into the main core area. Simultaneously, the 8% to 12% auxiliary gas volume is precisely calculated to provide sufficient kinetic energy for the disturbance without causing a sudden drop in the ash-to-gas ratio due to excessive gas supply, thus preventing secondary settling downstream. The orifice diameter of the throttling plate is precisely machined according to the main gas source pressure and the required flow range, and the pressure difference before and after it is designed to be a constant value, thereby ensuring the stability of the auxiliary airflow and preventing it from being affected by minor fluctuations in the main gas source pressure. In the horizontal straight pipe section, anti-clogging valves every 15 meters primarily address material deceleration and accumulation caused by accumulated frictional losses during long-distance transport. Their auxiliary airflow periodically "refreshes" the flow field inside the pipe, maintaining the material's suspended state.

[0042] In step S4, the opening of the anti-blocking valve is driven by a pilot-operated self-sensing mechanism. This mechanism receives the air pressure signal from the pressure sensing unit in step S1. When the signal reaches the pneumatic threshold of the corresponding blockage warning state, it directly pushes the valve core to move, opens the air passage, and achieves zero-delay response. The pilot-operated self-sensing mechanism has no electronic components or electromagnetic parts inside and relies entirely on the air pressure difference to drive the mechanical valve group to move.

[0043] Specifically, the pilot-operated self-sensing mechanism includes a sensitive chamber, a comparator diaphragm, a drive push rod, and an actuating valve core. When the air pressure in the sensitive chamber reaches the set value, the diaphragm is displaced and directly opens the main valve port through the push rod, opening the auxiliary air supply passage. The response time of this mechanism is less than 0.2 seconds, and the reset relies on the combined action of the built-in spring and the downstream back pressure. The set pressure of the pilot-operated self-sensing mechanism can be adjusted offline by replacing springs of different stiffness or adjusting the pre-compression amount to adapt to the operating requirements under different ash quality, conveying distance, and pipe diameter conditions. The adjustment range covers 0.2MPa to 0.6MPa. The operating principle of this mechanism is as follows: the air signal from the pressure sensing unit is introduced into the sensitive chamber and acts on one side of a fluororubber comparator diaphragm with a diameter of 25 mm. The other side of the diaphragm is exposed to a reference pressure chamber established by a pre-compression spring. Under normal conditions, the reference pressure is greater than or equal to the sensing signal pressure, the diaphragm remains in place, and the actuating valve core is in the closed state under the action of the reset spring. Once the sensing signal pressure exceeds the preset threshold, the diaphragm overcomes the spring force and displaces. This displacement is transmitted directly to the actuator valve core via a precision-ground stainless steel transmission push rod, instantly pushing it open from the valve seat. The auxiliary air source then enters the main pipeline through the opened valve port. The entire process is purely mechanical, without any intermediate conversion steps, resulting in extremely fast response. When the blockage warning is lifted, the sensing signal pressure drops, and the built-in spring, combined with the back pressure in the main pipeline, pushes the valve core back to the closed position, cutting off the auxiliary airflow. To adapt to different operating conditions, the mechanism is designed with a standardized spring replacement interface. Maintenance personnel can select a spring with appropriate stiffness (for example, for poorly flowing settled ash, a softer spring is selected to lower the trigger threshold) while the system is stopped, based on parameters such as the angle of repose and average particle size of the conveyed material, thus achieving a physical-level adjustment of the system's sensitivity.

[0044] Step S5: After the auxiliary gas supply is completed, if the pressure returns to the normal delivery range, the anti-blockage valve is closed and the main delivery process continues; if the pressure is still high, it is determined that the main pipeline is severely blocked, and the purging procedure is started. High-pressure gas pulses are used to reverse-impact the blocked section until the pressure drops, and then the normal delivery cycle is restarted. The whole process does not require human intervention or external controller participation in decision-making.

[0045] Specifically, the purging procedure uses intermittent high-pressure pulses, each lasting 2 seconds with a 5-second interval, executed a maximum of 3 times. If the blockage is still not cleared, a local audible and visual alarm is triggered, prompting manual inspection to avoid unnecessary air waste. The purging procedure's activation logic is built into the system's underlying layer. When the pilot mechanism determines a complete blockage, it simultaneously sends a pneumatic signal to the purging control unit. This control unit, also a purely pneumatic logic loop, opens a quick-release valve connected to the high-pressure air tank upon receiving the signal, injecting a 2-second high-pressure airflow (up to 0.8 MPa) into the blocked section. The valve then closes, and the system waits 5 seconds for the pressure wave to fully act on the blockage. This process is repeated a maximum of 3 times. If, after 3 pulses, the pressure sensing unit still does not detect a pressure drop, the blockage is considered too stubborn. The system then issues a local alarm via a pneumatically driven mechanical buzzer and warning light, notifying operators to handle the situation, thus avoiding the waste of large amounts of compressed air on ineffective purging.

[0046] Based on the aforementioned method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines, this method further includes a low-pressure holding phase after the main pipeline conveying process is completed. This phase maintains the residual pressure within the pipeline between 0.1 MPa and 0.15 MPa for 30 seconds, utilizing the residual airflow to slowly flush the pipe wall, removing adhering ash and reducing static friction resistance during the next conveying start-up. This phase is achieved by briefly opening a bypass throttle valve after the main conveying valve is closed. The flow capacity of this throttle valve is calculated to maintain the required low pressure. Simultaneously, the main conveying air source pressure is dynamically adjusted based on the maximum instantaneous pressure within the current conveying cycle. If no anti-blocking action is triggered for three consecutive cycles, the starting pressure of the next cycle is automatically reduced by 0.05 MPa, down to a minimum of 0.35 MPa, achieving on-demand air supply and avoiding energy waste caused by excessive pressurization. This dynamic adjustment function is implemented by a simple pneumatic memory loop that records whether an anti-blocking event occurred in the last three conveying cycles. If all three are "no," a feedback mechanism using a pneumatic pressure reducing valve lowers the starting pressure setting for the next cycle by 0.05 MPa. This process is repeated until the pressure drops to the lower limit of 0.35MPa, thereby continuously optimizing energy consumption while ensuring safe transportation.

[0047] To verify the technical effectiveness of this invention, a specific application example is constructed. This example is applied to the ash conveying system of an electrostatic precipitator in a 600MW coal-fired power plant. The main conveying pipeline of the system is 120 meters long, including four 90-degree bends, with a diameter of DN150, made of wear-resistant alloy steel, and a wall thickness of 12 mm (conventional design is 8 mm). The system adopts the method described in this invention and is equipped with eight anti-clogging valves and three pressure sensing units. Among them, there are six anti-clogging valves, one every 15 meters in the horizontal section, and one before each of the two bends; the first pressure sensing unit is located 0.5 meters from the outlet of the silo pump, the second is located 2 meters before the second bend, and the third is located at the bottom of the vertical riser pipe. The auxiliary air source shares the same compressed air system as the main air source, but passes through an independent filtration and pressure reducing device before entering the anti-clogging valve to ensure that the air source is clean and dry, with a dew point temperature below -20℃, to prevent moisture condensation and ash adhesion. The system operates under dense phase full-pipe conveying conditions with an ash-to-air ratio of 40:1, a target conveying velocity of 8 m / s, and a single conveying frequency of 5 times per hour.

[0048] In a typical conveying cycle, after the silo pump completes pressurization, the main conveying valve opens, and the pressure at the first monitoring point rapidly rises from 0 to 0.35 MPa and stabilizes. The pressures at the second and third monitoring points then rise steadily to 0.38 MPa and 0.42 MPa respectively, both within the normal range. In the third conveying cycle, due to a new batch of fly ash containing a large amount of unburned carbon particles, its fluidity deteriorated. Approaching the second bend, the pressure at the second monitoring point began to rise abnormally, increasing from 0.38 MPa to 0.48 MPa within 10 seconds, exceeding the second preset threshold of 0.455 MPa. The pilot-operated self-sensing mechanism of the anti-blocking valve, located 3 meters before the bend, responded immediately, opening within 0.15 seconds, injecting 8% of the auxiliary airflow in a spiral disturbance manner. Two seconds later, the pressure at the second monitoring point began to drop, recovering to 0.39 MPa after 5 seconds. The anti-blocking valve automatically closed, and the conveying was successfully completed. Since the anti-clogging mechanism was not triggered for three consecutive cycles (the 4th, 5th, and 6th), the system automatically lowered the initial pressure to 0.30 MPa during the 7th transport. Throughout the operation, the pipe wear rate, monitored by an ultrasonic thickness gauge, showed an average annual wall thickness reduction of only 0.15 mm, far lower than the 0.35 mm before the upgrade. It is estimated that the valve life can be extended to more than 2.3 times that of the original system. Statistics on air consumption per unit of material transport show a 42% reduction compared to before the upgrade, and the overall system energy saving rate reached 36%.

[0049] Example 2

[0050] Building upon the aforementioned Embodiment 1, and considering that large power plants often employ multi-branch ash conveying networks, the method of this invention also supports the coordinated operation of such networks. Each branch pipeline is equipped with an independent pilot-operated self-sensing anti-clogging unit, operating independently without signal interaction and relying on local pressure sensing to prevent any abnormality in one branch from affecting the normal operation of other lines. In this embodiment, a central ash silo conveys fly ash to three different ash fields via three independent branch pipelines. Each branch pipeline, following the principles of Embodiment 1, is equipped with complete pressure monitoring points, anti-clogging valves, and pilot-operated self-sensing mechanisms. The operation of the three branches is completely decoupled and does not affect each other. For example, when branch A triggers anti-clogging action due to ash quality issues, the conveying processes of branches B and C remain undisturbed, continuing to operate stably with their respective optimal parameters. This decentralized control architecture greatly enhances the reliability and flexibility of the entire ash conveying network. Even if a branch experiences severe blockage requiring manual intervention, the remaining branches can still maintain normal ash removal operations at the power plant, ensuring the safe and stable operation of the units.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines, characterized in that, The specific steps include the following: Step S1: Monitor the real-time pressure changes in the main conveying pipeline of the pneumatic ash conveying system. Through pressure sensing units set at key locations at the beginning, middle and end of the conveying process, continuously collect pressure data throughout the entire conveying process. Step S2: Based on the pressure data, identify the conveying operation status, divide the pressure curve into multiple feature intervals, and determine the normal conveying state when the pressure rise rate is lower than the first preset threshold and remains in the stable range. When the pressure continues to rise and exceeds the second preset threshold but does not reach the limit pressure, it is determined to be a blockage warning state. When the pressure rapidly rises to the third preset threshold and remains at a high level, it is determined to be a complete blockage state. Step S3: When the blockage warning state is determined, the auxiliary gas supply action is triggered. By opening the anti-blockage valve set upstream of the blockage-prone area, the auxiliary airflow is introduced into the main pipeline. The auxiliary airflow is injected in the form of a lateral jet to disturb the deposited material and rebuild the uniform mixing state of ash and gas, so that the fly ash that has begun to accumulate can re-enter the suspension propulsion mode. Step S4: The opening of the anti-blocking valve is driven by a pilot-operated self-sensing mechanism. This mechanism receives the air pressure signal from the pressure sensing unit. When the signal reaches the pneumatic threshold of the corresponding blockage warning state, it directly pushes the valve core to move and opens the ventilation channel, achieving zero-delay response. The pilot-operated self-sensing mechanism has no electronic components or electromagnetic parts inside and relies entirely on the air pressure difference to drive the mechanical valve group to move. Step S5: After the auxiliary gas supply is completed, if the pressure returns to the normal delivery range, close the anti-blockage valve and continue the main delivery process; if the pressure is still high, it is determined that the main pipeline is seriously blocked, start the purging program, use high-pressure gas pulses to reverse impact the blocked section until the pressure drops, and then re-enter the normal delivery cycle.

2. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The pressure sensing unit adopts a pure pneumatic diaphragm structure, and its output signal is the change in air pressure, which is used to characterize the pressure characteristics of the current conveying stage, including pressurization at the start of conveying, pressure stabilization during normal flow, increase in local resistance, and pressurization before blockage. The pressure sensing unit is arranged at the first monitoring point 0.5 meters away from the outlet of the silo pump, the second monitoring point 2 meters before the bend in the middle section of the horizontal pipe, and the third monitoring point at the bottom of the vertical riser pipe. Each monitoring point is equipped with a high-temperature and corrosion-resistant metal diaphragm sensor with a response frequency of not less than 10Hz.

3. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The first preset threshold is set to ±10% of the average conveying pressure; the second preset threshold is set to 1.3 times the average pressure; the third preset threshold is set to 1.8 times the average pressure; each preset threshold is calibrated based on historical operating data and material characteristics to form a fixed pneumatic feedback set point, which is solidified in the pilot mechanism by constant pressure in the air chamber.

4. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The anti-blocking valves are installed every 15 meters in horizontal straight pipe sections, 3 meters before 90-degree bends, and 5 meters upstream of reducing pipes. Each anti-blocking valve is connected to an independent auxiliary gas source branch, and the branch inlet is equipped with a throttling orifice plate to control the auxiliary gas flow rate to 8% to 12% of the main gas flow rate.

5. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The nozzle angle of the lateral jet is set to form a 30-degree angle with the axis of the main pipe, and the nozzle diameter is 6 mm. Three nozzles are evenly distributed along the circumference to form a spiral turbulent airflow field.

6. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The pilot-operated self-sensing mechanism includes a sensitive chamber, a comparison diaphragm, a transmission push rod, and an actuation valve core. When the air pressure in the sensitive chamber reaches the set value, the diaphragm is displaced and directly pushes open the main valve port through the push rod, opening the auxiliary air supply passage. The mechanism's action response time is less than 0.2 seconds, and the reset relies on the combined action of the built-in spring and the downstream back pressure.

7. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 6, characterized in that: The set pressure of the pilot-operated self-sensing mechanism can be adjusted offline by replacing springs of different stiffness or adjusting the pre-compression amount, with an adjustment range covering 0.2MPa to 0.6MPa.

8. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: After the main pipeline transportation is completed, a low-pressure holding stage is added to maintain the residual pressure in the pipeline between 0.1MPa and 0.15MPa for 30 seconds, and the residual airflow is used to slowly flush the pipe wall.

9. The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The main gas supply pressure is dynamically adjusted based on the maximum instantaneous pressure during the current delivery cycle. If the anti-blocking action is not triggered for three consecutive cycles, the starting pressure of the next cycle will be automatically reduced by 0.05 MPa, with a minimum of 0.35 MPa.

10. The method for mitigating wear and optimizing energy consumption in pneumatic ash conveying pipelines according to claim 1, characterized in that: The method for reducing wear and optimizing energy consumption in pneumatic ash conveying pipelines is applied to dense phase full-pipe conveying conditions with an ash-to-gas ratio greater than 35:

1. The conveying velocity is controlled within the range of 6m / s to 10m / s, and the frequency of a single conveying operation does not exceed 6 times per hour.

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