High-alkali coal fluidized bed boiler circulating material online continuous screening and adding system and device

Abstract

The invention discloses an online continuous screening and adding system and device for circulating materials of a high-alkali coal fluidized bed boiler, and belongs to the technical field of material circulation and control of fluidized bed boilers. The system comprises a device structure, a detection module, a control module and an alarm module, the device structure is sequentially connected with a slag cooler, a chain bucket machine, a bucket elevator, a screening system, a circulating material bin, a pneumatic conveying device and a slag bin through a material conveying path, and the pneumatic conveying device is connected to bed material adding ports with different heights of a boiler through a plurality of branch pipes; the detection module comprises a bed temperature sensor, a material level sensor, a flow sensor and a screening efficiency detection unit; the control module is electrically connected with the detection module, the pneumatic conveying device and the screening system, and the alarm module is used for abnormal alarm. According to the high-alkali coal fluidized bed boiler, whole-process online continuous treatment of circulating materials is achieved, accurate control and self-adaptive adjustment can be achieved according to bed temperature distribution in the boiler and coal quality changes, and the operation stability, the combustion efficiency and the intelligent level of the high-alkali coal fluidized bed boiler are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluidized bed boiler material circulation and control, in particular to a high-alkali coal fluidized bed boiler circulating material online continuous screening and adding system and device. BACKGROUND

[0002] In the field of high-alkali coal fluidized bed boiler operation, efficient screening and accurate addition of circulating material are key links to ensure stable combustion and improve efficiency of the boiler. However, there are many problems in this link in the prior art: lack of integrated online continuous screening and adding device, loose connection of cold slag separator, chain bucket machine, bucket elevator, screening system, circulating material bin, pneumatic conveying device and slag bin in the material conveying path, poor sealing performance, not only causing a large amount of dust leakage and material waste, but also lacking necessary buffer and detection mechanism for connection between devices, resulting in serious instability of material conveying. At the same time, for different height bed material adding ports of the boiler, it is impossible to realize differentiated material addition, which is difficult to meet the bed temperature control requirements of different areas in the furnace. In addition, the system lacks the cooperation of multi-dimensional detection modules (such as bed temperature, material level, flow, screening efficiency, etc.) and intelligent control modules, which makes the bed temperature control precision low, the material level management chaotic, and the screening efficiency cannot be effectively guaranteed, ultimately leading to low operation efficiency and poor stability of the high-alkali coal fluidized bed boiler, which is difficult to adapt to the complex combustion characteristics of high-alkali coal. SUMMARY

[0003] In view of the defects in the prior art, the purpose of the present application is to provide a high-alkali coal fluidized bed boiler circulating material online continuous screening and adding system and device, which realizes online continuous processing of circulating material in the whole process, and can realize precise control and self-adaptive adjustment according to the bed temperature distribution in the furnace, coal quality change and the like.

[0004] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0005] This application provides an online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler, comprising: a device structure including a slag cooler, a chain bucket elevator, a bucket elevator, a screening system, a circulating material silo, a pneumatic conveying device, and a slag silo, connected sequentially via a material conveying path; the discharge end of the pneumatic conveying device being connected to different bed material addition ports at different heights of the boiler via multiple branch pipes; a detection module including at least three bed temperature sensors spaced apart along the height of the boiler furnace, a material level sensor located in the circulating material silo, flow sensors located at the fine slag discharge port and the large slag discharge port of the screening system, and a screening efficiency detection unit for sampling and online particle size analysis of the fine slag; a control module electrically connected to the detection module, the pneumatic conveying device, and the screening system; and an alarm module connected to the control module for issuing an alarm when the material level, bed temperature, or screening efficiency is abnormal.

[0006] Furthermore, the control module is configured to perform bed temperature-flow coupling control and material level collaborative management, specifically including: preset target bed temperature threshold, material level threshold of the circulating material bin, and target flow range of fine slag. The preset target bed temperature threshold includes a first temperature threshold and a second temperature threshold, and the second temperature threshold is lower than the first temperature threshold. The material level threshold includes a minimum material level threshold and a maximum material level threshold. Based on the comparison between the target bed temperature threshold and the detected bed temperature, if the detected bed temperature is higher than the first temperature threshold, the flow regulating valve of the pneumatic conveying device is controlled to increase its opening to increase the fine slag conveying flow; if the detected bed temperature is lower than the second temperature threshold, the flow regulating valve is controlled to decrease its opening to reduce the fine slag conveying flow. Based on the comparison between the material level threshold and the detected material level, if the detected material level is lower than the minimum material level threshold, the vibration motor of the screening system is controlled to increase its vibration frequency and increase the conveying speed of the chain bucket elevator and bucket elevator; if the detected material level is higher than the maximum material level threshold, the vibration motor is controlled to decrease its vibration frequency and decrease the conveying speed of the chain bucket elevator and bucket elevator.

[0007] Furthermore, the control module is also configured to perform bed temperature uniformity control, specifically including: comparing the temperature values ​​detected by bed temperature sensors at different heights in real time; when the maximum temperature difference of the temperature values ​​exceeds a preset first threshold, independently adjusting the opening of the flow regulating valve on the branch pipe connected to the corresponding height bed material addition port, increasing the amount of material added in the high-temperature area and decreasing the amount of material added in the low-temperature area, until the maximum temperature difference of the temperature values ​​is less than a preset second threshold, and the preset first threshold is greater than the preset second threshold.

[0008] Furthermore, the control module also has an adaptive learning function, specifically including: recording the bed temperature change curve, circulating material addition flow curve and screening system operating parameters under different coal quality conditions, and establishing a coal quality-operating parameter matching model based on historical operating data; the control module is configured to call the matching model according to the current coal quality data, and automatically adjust the target bed temperature threshold, the target flow range of fine slag and the vibration frequency setting value of the screening system.

[0009] Furthermore, it also includes a remote monitoring and diagnostic module, which is connected to the control module via an industrial Ethernet. The remote monitoring and diagnostic module is used to display the system operating status, detection data and control parameters in real time, and supports remote parameter modification and historical data query. The remote monitoring and diagnostic module also has a fault diagnosis function, which can locate the fault location and generate processing suggestions based on the fault tree analysis method, according to the detection data and equipment operating parameters.

[0010] Accordingly, this application also provides an online continuous screening and addition device for circulating materials in a high-alkali coal fluidized bed boiler, comprising: a slag cooler, the feed end of which is sealed and connected to the furnace slag discharge port; a chain bucket conveyor, the feed end of which receives the discharge end of the slag cooler; a bucket elevator, the feed end of which is connected to the discharge end of the chain bucket conveyor through a buffer transition chamber, the buffer transition chamber being equipped with a material level detection device; and a screening system, the feed inlet of which is directly connected to the discharge outlet of the bucket elevator, and the connection point is provided with... It has a sealed dust cover; the screening system is equipped with a fine slag outlet and a large slag outlet; a circulating material bin, the inlet of which is connected to the fine slag outlet of the screening system through an anti-clogging pipe with a wear-resistant coating on the inner wall; a pneumatic conveying device, the inlet of which is connected to the discharge valve at the bottom of the circulating material bin, and the outlet of which includes multiple branch pipes extending to different height bed material addition ports of the boiler; and a slag bin, which is connected to the large slag outlet of the screening system through a chute lined with a high-temperature wear-resistant plate.

[0011] Further, the screening system includes: a screening box, the top of which is provided with a feed inlet, and the lower two sides are respectively provided with a fine slag outlet and a large slag outlet; an inclined screen, the inclined screen being fixed in the screening box at an angle of 15-30°, with a screen aperture of 0.5-2mm; a vibrating motor, the vibrating motor being fixed on the outer wall of the screening box; and a slag cleaning assembly, the slag cleaning assembly including a drive cylinder fixed to the screening box and a scraper connected to the piston rod of the drive cylinder, the scraper being configured to reciprocate and clean the slag against the surface of the inclined screen under the drive of the drive cylinder.

[0012] Furthermore, the pneumatic conveying device includes: a Roots blower; a main conveying pipe, one end of which is connected to the outlet of the Roots blower; multiple branch pipes, which are connected in parallel to the other end of the main conveying pipe, with the outlet of each branch pipe corresponding to a boiler bed material inlet; and an electric flow regulating valve, which is connected in series on each branch pipe to independently and precisely control the conveying flow of each branch pipe, with an adjustment accuracy of ±0.1t / h.

[0013] Furthermore, the circulating material silo includes: a silo body, the lower part of which is a conical structure with a cone angle of 60-90°, and the top of which is provided with a feed inlet and a dust collector interface; a silo top dust collector, which is installed on the dust collector interface; and a rotary valve, which is located at the bottom discharge port of the conical structure of the silo body, and the discharge end of the rotary valve is connected to the feed end of the pneumatic conveying device through a flange.

[0014] Furthermore, the inner wall of the anti-clogging pipe is provided with a polytetrafluoroethylene wear-resistant coating with a coating thickness of 1-3mm; the connection between the anti-clogging pipe and the fine slag outlet of the screening system, as well as the inlet of the circulating material bin, are all provided with elastic sealing gaskets made of high-temperature resistant silicone rubber.

[0015] The beneficial effects of this invention are as follows: by integrating the device structure, detection, control and alarm modules, it realizes online continuous processing of circulating materials throughout the entire process; multi-branch pipes convey materials at different heights, and multi-dimensional detection provides data for precise control and alarm, which greatly improves the system stability, bed temperature control accuracy and screening reliability. Attached Figure Description

[0016] Figure 1 This application provides a schematic diagram of the structure of an online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler.

[0017] Figure 2 This application provides a schematic diagram of the structure of an online continuous screening and addition device for circulating materials in a high-alkali coal fluidized bed boiler.

[0018] Figure 3 for Figure 2 A schematic diagram of the internal structure of the screening system in the middle.

[0019] Attached reference numerals: 1-furnace, 2-slag cooler, 3-chain bucket conveyor, 4-screening system, 41-large slag outlet, 42-fine slag outlet, 43-screening box, 44-inclined screen, 45-drive cylinder, 46-scraper, 5-bucket elevator, 6-circulating material bin, 7-pneumatic conveying device, 71-main conveying pipe, 72-branch pipe, 73-electric flow regulating valve, 8-slag bin. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0021] In this invention, the terms "system" and "network" are used interchangeably. "Multiple" refers to two or more; therefore, in this invention, "multiple" can also be understood as "at least two." "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / ", unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, it should be understood that in the description of this invention, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0022] Example 1

[0023] like Figure 1 As shown in the figure, this application provides an online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler, comprising: a device structure, the device structure including a slag cooler 2, a chain bucket elevator, a bucket elevator, a screening system 4, a circulating material silo 6, a pneumatic conveying device 7, and a slag silo 8 connected sequentially through a material conveying path, wherein the discharge end of the pneumatic conveying device 7 is connected to the bed material addition ports at different heights of the boiler through multiple branch pipes 72; a detection module, the detection module including at least three bed temperature sensors spaced apart along the height direction of the boiler furnace 1, a material level sensor installed in the circulating material silo 6, flow sensors installed at the fine slag discharge port 42 and the large slag discharge port 41 of the screening system 4, and a screening efficiency detection unit for sampling and online particle size analysis of the fine slag; a control module, the control module being electrically connected to the detection module, the pneumatic conveying device 7, and the screening system 4; and an alarm module, the alarm module being connected to the control module for issuing an alarm when the material level, bed temperature, or screening efficiency is abnormal.

[0024] In another possible embodiment, the slag cooler 2 is sealed and connected to the slag discharge port of the furnace 1. The material is sent to the screening system 4 via a chain bucket elevator and a bucket elevator. Fine slag enters the circulating material bin 6 and is then sent to the bed material addition ports at different heights of the boiler through multiple branch pipes 72 of the pneumatic conveying device 7. Large slag enters the slag bin 8. At least three bed temperature sensors are installed along the height of the furnace 1. The material level sensor is installed in the circulating material bin 6. The flow sensor is installed at the fine slag and large slag discharge ports 41 of the screening system 4. The screening efficiency detection unit samples the fine slag and performs online particle size analysis. The control module is electrically connected to the detection module, the pneumatic conveying device 7 and the screening system 4. The alarm module alarms when the material level, bed temperature or screening efficiency is abnormal.

[0025] By integrating the device structure, detection, control, and alarm modules, the entire process of circulating materials can be continuously processed online. The multi-branch pipe conveys materials at a height of 72 points, and multi-dimensional detection provides data for precise control and alarms, greatly improving system stability, bed temperature control accuracy, and screening reliability.

[0026] Bed temperature control is a crude adjustment based on a single threshold. There is no coordination between material level management and bed temperature control, resulting in large fluctuations in bed temperature. When the material level in the silo is abnormal, the system does not respond in a timely manner, which affects the stable operation of the boiler.

[0027] In the embodiments of this application, the control module is configured to perform bed temperature-flow coupling control and material level collaborative management, specifically including: preset target bed temperature threshold, material level threshold of circulating material bin 6, and target flow range of fine slag. The preset target bed temperature threshold includes a first temperature threshold and a second temperature threshold, and the second temperature threshold is lower than the first temperature threshold. The material level threshold includes a minimum material level threshold and a maximum material level threshold. Based on the comparison between the target bed temperature threshold and the detected bed temperature, if the detected bed temperature is higher than the first temperature threshold, the flow regulating valve of the pneumatic conveying device 7 is controlled to increase its opening to increase the fine slag conveying flow rate; if the detected bed temperature is lower than the second temperature threshold, the flow regulating valve is controlled to decrease its opening to reduce the fine slag conveying flow rate. Based on the comparison between the material level threshold and the detected material level, if the detected material level is lower than the minimum material level threshold, the vibration motor of the screening system 4 is controlled to increase its vibration frequency and increase the conveying speed of the chain bucket machine and bucket elevator; if the detected material level is higher than the maximum material level threshold, the vibration motor is controlled to decrease its vibration frequency and decrease the conveying speed of the chain bucket machine and bucket elevator.

[0028] In another possible embodiment, the control module presets a target bed temperature threshold (including a first temperature threshold and a lower second temperature threshold), a material level threshold (minimum and maximum material level thresholds) for the circulating material bin 6, and a target flow range for fine slag. It compares the detected bed temperature with the target bed temperature threshold. If the detected temperature is higher than the first temperature threshold, it controls the flow regulating valve of the pneumatic conveying device 7 to increase its opening and increase the fine slag conveying flow. If the detected temperature is lower than the second temperature threshold, it controls the flow regulating valve to decrease its opening and reduce the fine slag conveying flow. It also compares the detected material level with the material level threshold. If the detected material level is lower than the minimum material level threshold, it controls the vibration motor of the screening system 4 to increase its vibration frequency and increase the conveying speed of the chain bucket elevator and bucket elevator. If the detected material level is higher than the maximum material level threshold, it controls the vibration motor to decrease its vibration frequency and decrease the conveying speed of the chain bucket elevator and bucket elevator.

[0029] By implementing bed temperature-flow coupled control and material level coordinated management, dual temperature thresholds and material level thresholds enable precise bed temperature control, and coordinated material level and bed temperature regulation avoids large fluctuations in bed temperature and abnormal material levels in the material bins, ensuring stable and efficient boiler operation.

[0030] The existing system has a crude bed temperature control method, which cannot accurately adjust the bed temperature according to the differences in bed temperature at different heights in the furnace. The uneven bed temperature distribution affects the boiler combustion efficiency and stability.

[0031] In an embodiment of this application, the control module is further configured to perform bed temperature uniformity control, specifically including: comparing the temperature values ​​detected by bed temperature sensors at different heights in real time; when the maximum temperature difference of the temperature values ​​exceeds a preset first threshold, independently adjusting the opening of the flow regulating valve on the branch pipe 72 connected to the corresponding height bed material addition port, increasing the amount of material added in the high-temperature area and decreasing the amount of material added in the low-temperature area, until the maximum temperature difference of the temperature values ​​is less than a preset second threshold, and the preset first threshold is greater than the preset second threshold.

[0032] In another possible embodiment, the temperature values ​​detected by the bed temperature sensors at different heights are compared in real time. When the maximum temperature difference exceeds a preset first threshold, the opening of the flow regulating valve on the branch pipe 72 connected to the corresponding height bed material addition port is independently adjusted to increase the amount of material added in the high-temperature area and decrease the amount of material added in the low-temperature area until the maximum temperature difference is less than a preset second threshold (the preset first threshold is greater than the preset second threshold).

[0033] By achieving uniform bed temperature control, the material flow rate at the corresponding height bed material addition port can be independently adjusted according to the temperature difference at different heights in the furnace, so that the bed temperature distribution in the furnace is uniform, further improving the boiler combustion efficiency and stability.

[0034] The existing system lacks an adaptive operating parameter adjustment mechanism for different coal qualities (especially the changes in ash content and Na / K element content of high-alkali coal). When the coal quality changes, parameters need to be adjusted frequently by hand, which is cumbersome and can easily affect the stability of boiler operation.

[0035] In the embodiments of this application, the control module also has an adaptive learning function, specifically including: recording the bed temperature change curve, the circulating material addition flow curve and the operating parameters of the screening system 4 under different coal quality conditions, and establishing a coal quality-operating parameter matching model based on historical operating data; the control module is configured to call the matching model according to the current coal quality data, and automatically adjust the target bed temperature threshold, the target flow range of fine slag and the vibration frequency setting value of the screening system 4.

[0036] In another possible embodiment, the bed temperature change curve, the circulating material addition flow curve, and the operating parameters of the screening system 4 under different coal quality conditions are recorded. A coal quality-operating parameter matching model is established based on historical operating data. The control module calls the matching model according to the current coal quality data and automatically adjusts the target bed temperature threshold, the target flow range of fine slag, and the vibration frequency setting value of the screening system 4.

[0037] The control module has an adaptive learning function, which can automatically adjust the operating parameters according to different coal qualities, realize rapid adaptation after coal quality changes, and improve the system's adaptability to coal quality changes and the level of intelligent operation without frequent manual intervention.

[0038] The existing system lacks effective remote monitoring and fault diagnosis methods, and maintenance personnel cannot fully grasp the system's operating status in real time, resulting in low efficiency in fault location and handling.

[0039] In embodiments of this application, a remote monitoring and diagnostic module is also included, which is connected to the control module via an industrial Ethernet. The remote monitoring and diagnostic module is used to display the system operating status, detection data and control parameters in real time, and supports remote parameter modification and historical data query. The remote monitoring and diagnostic module also has a fault diagnosis function, which can locate the fault location and generate processing suggestions based on the fault tree analysis method, according to the detection data and equipment operating parameters.

[0040] In another possible embodiment, the remote monitoring and diagnostic module is connected to the control module via an industrial Ethernet to display the system operating status, detection data and control parameters in real time. It supports remote modification of control parameters and viewing of historical data. It can also locate the fault location and generate handling suggestions based on the fault tree analysis method, according to the detection data and equipment operating parameters.

[0041] The remote monitoring and diagnostic module enables real-time remote monitoring of system operation status, remote modification of parameters, and query of historical data. It also has fault diagnosis function, which can quickly locate the fault and generate handling suggestions, thereby improving the efficiency and intelligence of system operation and maintenance.

[0042] Example 2

[0043] Please refer toFigures 2-3 Accordingly, this application also provides an online continuous screening and addition device for circulating materials in a high-alkali coal fluidized bed boiler, comprising: a slag cooler 2, the feed end of which is sealed and connected to the slag discharge port of the furnace 1; a chain bucket conveyor 3, the feed end of which receives the discharge end of the slag cooler 2; a bucket elevator 5, the feed end of which is connected to the discharge end of the chain bucket conveyor 3 through a buffer transition chamber, the buffer transition chamber being equipped with a material level detection device; and a screening system 4, the feed inlet of which is directly connected to the discharge outlet of the bucket elevator 5, and a sealing device is provided at the connection point. The system includes a dust cover; a screening system 4 with a fine slag outlet 42 and a large slag outlet 41; a circulating material bin 6, whose inlet is connected to the fine slag outlet 42 of the screening system 4 via an anti-clogging pipe with a wear-resistant coating on its inner wall; a pneumatic conveying device 7, whose inlet is connected to the discharge valve at the bottom of the circulating material bin 6, and whose outlet includes multiple branch pipes 72 extending to different height bed material addition ports of the boiler; and a slag bin 8, which is connected to the large slag outlet 41 of the screening system 4 via a chute lined with a high-temperature wear-resistant liner.

[0044] In another possible embodiment, the feed end of the slag cooler 2 is sealed and connected to the slag discharge port of the furnace 1, the feed end of the chain bucket conveyor 3 receives the discharge end of the slag cooler 2, the feed end of the bucket elevator 5 is connected to the discharge end of the chain bucket conveyor 3 through a buffer transition bin with an internal material level detection device, the feed port of the screening system 4 is directly connected to the discharge port of the bucket elevator 5 and is equipped with a sealed dust cover, the fine slag discharge port 42 of the screening system 4 is connected to the feed port of the circulating material bin 6 through an anti-clogging pipe with a wear-resistant coating on the inner wall, the feed end of the pneumatic conveying device 7 is connected to the bottom discharge valve of the circulating material bin 6 and the discharge end includes multiple branch pipes 72 extending to the bed material addition ports at different heights of the boiler, and the slag bin 8 is connected to the large slag discharge port 41 of the screening system 4 through a chute lined with a high-temperature wear-resistant liner.

[0045] The various devices in the device structure are tightly connected, and buffer transition chambers, sealed dust covers, and anti-clogging pipes are set up to improve the stability and sealing of material conveying and prevent dust leakage and material blockage. The multiple branch pipes 72 of the pneumatic conveying device 7 can independently convey materials to the bed material addition ports at different heights of the boiler to meet the bed material addition needs of different areas.

[0046] The existing screening system has four screens that are prone to clogging, and the slag is not cleaned in time, resulting in a decrease in screening efficiency, which affects the particle size control of circulating materials and consequently affects the boiler bed temperature control effect.

[0047] In an embodiment of this application, the screening system 4 includes: a screening box 43, with a feed inlet at the top and fine slag outlet 42 and large slag outlet 41 respectively on the lower sides; an inclined screen 44, fixed inside the screening box 43 at an angle of 15-30°, with a screen aperture of 0.5-2mm; a vibrating motor, fixed to the outer wall of the screening box 43; and a slag cleaning assembly, including a drive cylinder 45 fixed to the screening box 43 and a scraper 46 connected to the piston rod of the drive cylinder 45, the scraper 46 being configured to reciprocate and clean the slag against the surface of the inclined screen 44 under the drive of the drive cylinder 45.

[0048] In another possible embodiment, the screening box 43 of the screening system 4 is provided with a feed inlet, and fine slag outlet 42 and large slag outlet 41 are respectively provided on the lower two sides; the inclined screen 44 is fixed in the screening box 43 at an inclination angle of 15-30°, and the screen aperture is 0.5-2mm; the vibrating motor is fixed to the outer wall of the screening box 43; the drive cylinder 45 of the slag cleaning component is fixed to the screening box 43, and the scraper 46 is connected to the piston rod of the drive cylinder 45, and reciprocates to clean the slag by adhering to the surface of the inclined screen 44 under the drive of the drive cylinder 45.

[0049] By installing a slag-removing component in screening system 4, screen blockages can be cleaned in a timely manner, keeping the screen unobstructed, ensuring stable screening efficiency, guaranteeing that the particle size of the circulating material meets the requirements, and providing a guarantee for precise bed temperature control.

[0050] The existing pneumatic conveying devices are mostly single-path conveyors, which cannot independently and accurately control the flow rate at the material feeding ports at different heights of the boiler bed, resulting in uneven bed temperature distribution and affecting boiler combustion efficiency.

[0051] In the embodiments of this application, the pneumatic conveying device 7 includes: a Roots blower; a main conveying pipe 71, one end of which is connected to the outlet of the Roots blower; multiple branch pipes 72, which are connected in parallel to the other end of the main conveying pipe 71, with the outlet of each branch pipe 72 corresponding to a boiler bed material feeding port; and an electric flow regulating valve 73, which is connected in series on each branch pipe 72 for independently and precisely controlling the conveying flow of each branch pipe 72, with an adjustment accuracy of ±0.1t / h.

[0052] In another possible embodiment, the air outlet of the Roots blower of the pneumatic conveying device 7 is connected to the main conveying pipe 71, and the other end of the main conveying pipe 71 is connected in parallel to multiple branch pipes 72. The discharge end of each branch pipe 72 corresponds to a boiler bed material addition port. The electric flow regulating valve 73 is connected in series on each branch pipe 72 to independently and accurately control the conveying flow of each branch pipe 72 with an adjustment accuracy of ±0.1t / h.

[0053] By adopting a multi-branch pipe 72 design for the pneumatic conveying device 7, and equipping each branch pipe 72 with an electric flow regulating valve 73, the material flow rate at each bed material addition port can be independently and precisely controlled, with high adjustment accuracy, to meet the precise requirements of bed temperature uniformity control for the amount of material added in different areas.

[0054] The existing circulating material silo 6 is prone to dust accumulation, and the connection between the unloading valve and the pneumatic conveying device 7 is not well sealed, affecting the material conveying efficiency and system sealing.

[0055] In an embodiment of this application, the circulating material bin 6 includes: a bin body, the lower part of which is a conical structure with a cone angle of 60-90°, and the top of which is provided with a feed inlet and a dust collector interface; a bin top dust collector, which is installed on the dust collector interface; and a rotary valve, which is located at the bottom discharge port of the conical structure of the bin body, and the discharge end of the rotary valve is connected to the feed end of the pneumatic conveying device 7 through a flange.

[0056] In another possible embodiment, the lower part of the circulating material silo 6 is a conical structure with a cone angle of 60-90°, and the top is provided with a feed inlet and a dust collector interface. The dust collector on the top of the silo is installed at the dust collector interface. The star-shaped discharge valve is set at the discharge port at the bottom of the conical structure of the silo, and the discharge end of the star-shaped discharge valve is connected to the feed end of the pneumatic conveying device 7 through a flange.

[0057] By installing a dust collector on the top of the circulating material silo 6, dust inside the silo can be effectively removed, keeping the silo clean. The conical structure and star-shaped discharge valve design ensure smooth material discharge and reliable sealing when connected to the pneumatic conveying device 7, improving material conveying efficiency and system sealing.

[0058] Existing anti-clogging pipes have insufficient wear resistance and poor sealing at connection points, which can easily lead to pipe wear and dust leakage, affecting the continuous operation of the system and the working environment.

[0059] In the embodiments of this application, the inner wall of the anti-clogging pipe is provided with a polytetrafluoroethylene wear-resistant coating with a coating thickness of 1-3mm; the connection between the anti-clogging pipe and the fine slag outlet 42 of the screening system 4, and the inlet of the circulating material bin 6, are all provided with elastic sealing gaskets made of high-temperature resistant silicone rubber.

[0060] In another possible embodiment, the inner wall of the anti-clogging pipe is provided with a 1-3mm thick polytetrafluoroethylene wear-resistant coating; the connection between the anti-clogging pipe and the fine slag outlet 42 of the screening system 4 and the feed inlet of the circulating material bin 6 are all provided with elastic sealing gaskets made of high-temperature resistant silicone rubber.

[0061] By applying a PTFE wear-resistant coating to the inner wall of the anti-clogging pipe, the wear resistance of the pipe is improved, and the service life of the pipe is extended; high-temperature resistant silicone rubber elastic sealing gaskets are installed at the connection points to enhance the connection sealing performance, prevent dust leakage, and ensure continuous and stable operation of the system and a good working environment.

[0062] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0063] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0064] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. An online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler, characterized in that, include: The device structure includes a slag cooler, a chain bucket elevator, a bucket elevator, a screening system, a circulating material bin, a pneumatic conveying device, and a slag bin, which are connected in sequence through a material conveying path. The discharge end of the pneumatic conveying device is connected to the bed material addition port of the boiler at different heights through multiple branch pipes. The detection module includes at least three bed temperature sensors spaced apart along the height of the boiler furnace, a material level sensor installed in the circulating material bin, flow sensors installed at the fine slag outlet and the large slag outlet of the screening system, and a screening efficiency detection unit for sampling and online particle size analysis of the fine slag. The control module is electrically connected to the detection module, the pneumatic conveying device, and the screening system. An alarm module, which is connected to the control module, is used to issue an alarm when the material level, bed temperature, or screening efficiency is abnormal.

2. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 1, characterized in that, The control module is configured to perform bed temperature-flow coupled control and material level coordinated management, specifically including: The preset target bed temperature threshold, the material level threshold of the circulating material bin, and the target flow range of fine slag are defined. The preset target bed temperature threshold includes a first temperature threshold and a second temperature threshold, and the second temperature threshold is lower than the first temperature threshold. The material level threshold includes a minimum material level threshold and a maximum material level threshold. Based on the comparison between the target bed temperature threshold and the detection bed temperature, if the detection bed temperature is higher than the first temperature threshold, the flow regulating valve of the pneumatic conveying device is controlled to increase the opening to increase the fine slag conveying flow rate; if the detection bed temperature is lower than the second temperature threshold, the flow regulating valve is controlled to decrease the opening to reduce the fine slag conveying flow rate. Based on the comparison between the material level threshold and the detected material level, if the detected material level is lower than the minimum material level threshold, the vibration motor of the screening system is controlled to increase the vibration frequency and the conveying speed of the chain bucket machine and bucket elevator is increased; if the detected material level is higher than the maximum material level threshold, the vibration motor is controlled to decrease the vibration frequency and the conveying speed of the chain bucket machine and bucket elevator is reduced.

3. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 2, characterized in that, The control module is also configured to perform bed temperature uniformity control, specifically including: The temperature values ​​detected by the bed temperature sensors at different heights are compared in real time. When the maximum temperature difference exceeds a preset first threshold, the opening of the flow regulating valve on the branch pipe connected to the corresponding height bed material addition port is independently adjusted to increase the amount of material added in the high-temperature area and decrease the amount of material added in the low-temperature area until the maximum temperature difference is less than a preset second threshold and the preset first threshold is greater than the preset second threshold.

4. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 1, characterized in that, The control module also has an adaptive learning function, specifically including: Record the bed temperature change curve, circulating material addition flow rate curve and screening system operating parameters under different coal quality conditions, and establish a coal quality-operating parameter matching model based on historical operating data; The control module is configured to automatically adjust the target bed temperature threshold, the target flow range of fine slag, and the vibration frequency setting of the screening system based on the current coal quality data and by calling the matching model.

5. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 1, characterized in that, It also includes a remote monitoring and diagnostic module, which is connected to the control module via an industrial Ethernet; The remote monitoring and diagnostic module is used to display the system operating status, detection data and control parameters in real time, and supports remote parameter modification and historical data query. The remote monitoring and diagnostic module also has a fault diagnosis function, which can locate the fault location and generate handling suggestions based on the fault tree analysis method, according to the detection data and equipment operating parameters.

6. A continuous online screening and adding device for circulating materials in a high-alkali coal fluidized bed boiler, characterized in that, include: A slag cooler, wherein the feed end of the slag cooler is sealed and connected to the slag discharge port of the furnace; A chain bucket conveyor, wherein the feed end of the chain bucket conveyor receives the discharge end of the slag cooler; A bucket elevator, wherein the feed end of the bucket elevator is connected to the discharge end of the chain bucket conveyor through a buffer transition bin, and the buffer transition bin is equipped with a material level detection device; The screening system has its inlet directly connected to the outlet of the bucket elevator, and a sealed dust cover is provided at the connection point; the screening system is provided with a fine slag outlet and a large slag outlet. A circulating material bin, wherein the inlet of the circulating material bin is connected to the fine slag outlet of the screening system through an anti-clogging pipe with a wear-resistant coating on the inner wall; A pneumatic conveying device, wherein the feed end of the pneumatic conveying device is connected to the discharge valve at the bottom of the circulating material bin, and the discharge end of the pneumatic conveying device includes multiple branch pipes that extend to different height bed material addition ports of the boiler. The slag bin is connected to the large slag discharge port of the screening system via a chute lined with a high-temperature and wear-resistant liner.

7. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 6, characterized in that, The screening system includes: The screening box has a feed inlet at the top and fine slag outlets and large slag outlets on the lower two sides, respectively. An inclined screen is fixed in the screening box at an angle of 15-30°, and the screen aperture is 0.5-2mm. A vibrating motor is fixed to the outer wall of the screening box. The slag removal assembly includes a drive cylinder fixed to the screening box and a scraper connected to the piston rod of the drive cylinder. The scraper is configured to reciprocate and clean the slag against the surface of the inclined screen under the drive of the drive cylinder.

8. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 6, characterized in that, The pneumatic conveying device includes: Roots blower; A main conveying pipe, one end of which is connected to the outlet of the Roots blower; Multiple branch pipes are connected in parallel to the other end of the main conveying pipe, and the discharge end of each branch pipe corresponds to a boiler bed material feeding port. An electric flow regulating valve is connected in series on each of the branch pipes to independently and precisely control the flow rate of each branch pipe, with an adjustment accuracy of ±0.1t / h.

9. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 6, characterized in that, The circulating material bin includes: The silo body has a cone-shaped structure with a cone angle of 60-90° at the bottom and a feed inlet and a dust collector interface at the top. A silo top dust collector, wherein the silo top dust collector is installed on the dust collector interface; A rotary valve is provided at the bottom outlet of the conical structure of the silo, and the outlet end of the rotary valve is connected to the inlet end of the pneumatic conveying device via a flange.

10. The online continuous screening and addition system for circulating materials in a high-alkali coal fluidized bed boiler according to claim 6, characterized in that, The inner wall of the anti-clogging pipe is provided with a polytetrafluoroethylene wear-resistant coating with a coating thickness of 1-3mm; the connection between the anti-clogging pipe and the fine slag outlet of the screening system, as well as the inlet of the circulating material bin, are all provided with elastic sealing gaskets made of high-temperature resistant silicone rubber.

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