Coal mill material recovery system and method

Abstract

The invention relates to the technical field of boilers and discloses a coal mill material recycling system and method.The coal mill material recycling system comprises a collecting assembly, a sorting assembly, a draught fan, a mixer and a recycling pipeline, the sorting assembly comprises a feeding port, a first discharging port and a second discharging port, the feeding port is connected with the collecting assembly, and the collecting assembly is connected with the draught fan; the sorting assembly is used for receiving the mixture from the collecting assembly and sorting the mixture, pebble coal is discharged from the first discharging port, combustible components are discharged from the second discharging port, an air inlet of the fan communicates with the sorting assembly, the fan is used for driving the mixture to flow, and the air inlet and the air outlet both can communicate with the outside. And the mixer is used for receiving the combustible component of the second discharge port, mixing the combustible component with the positive pressure airflow from the fan and conveying the mixture back to the coal mill. According to the material recovery system of the coal mill, combustible effective raw coal in pebble coal can be separated and returned, the utilization rate of the raw coal is increased, and damage to the coal mill is avoided.

Description

Technical Field

[0001] This invention belongs to the field of boiler technology, specifically relating to a coal mill material recovery system and method. Background Technology

[0002] Coal mills produce coke pumice during operation. Coke pumice mainly consists of coal gangue, broken coal pieces, stones, and coal dust. Especially when the quality of the raw coal deteriorates or the mill operates poorly, the amount of coke pumice emitted by medium-speed mills increases significantly, and the coke pumice contains a high proportion of raw coal. In many related technologies, the coke pumice is added back to the raw coal and re-entered into the mill for grinding. However, re-entering the mill inevitably increases the amount of coke pumice in the mill, and the stones and ores contained in the coke pumice further exacerbate the wear and tear on the mill. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose a coal mill material recovery system that can separate and return combustible raw coal from coal slag, improving the utilization rate of raw coal and avoiding damage to the coal mill.

[0004] This invention also proposes a method for recovering materials from a coal mill, which can achieve multiple operating modes such as idling, sorting, recovery, and conventional operation to meet the needs of different application scenarios.

[0005] The coal mill material recovery system of this invention includes a collection component, a sorting component, a blower, a mixer, and a recovery pipeline. The collection component receives a mixture discharged from the coal mill. The sorting component includes an inlet, a first outlet, and a second outlet. The inlet is connected to the collection component. The sorting component receives the mixture from the collection component and sorts the mixture, so that coarse coal is discharged from the first outlet and combustible components are discharged from the second outlet. The inlet of the blower is connected to the sorting component, and the blower is used to... The sorting assembly generates a negative pressure airflow that drives the flow of the mixture. After passing through the fan, the negative pressure airflow forms a positive pressure airflow at the fan outlet. Both the inlet and outlet of the fan are connected to the outside. The mixer is connected to the second outlet of the sorting assembly and the outlet of the fan. The mixer is used to receive the combustible components from the second outlet and mix the combustible components with the positive pressure airflow from the fan. The recovery pipeline is located between the mixer and the coal mill and is used to transport the coal powder carried by the positive pressure airflow back to the coal mill.

[0006] The coal mill material recovery system of this invention changes the traditional crude method of directly re-mixing all the coking coal. Through a combination of negative pressure separation and positive pressure recovery, it achieves for the first time the effective separation and selective recovery of coking coal and combustible components (mainly pulverized coal and coal particles) in the coal mill discharge mixture. Only the separated combustible components are sent back to the coal mill, which significantly improves fuel utilization and completely prevents hard impurities such as ore and gangue from re-entering the coal mill, avoiding a vicious cycle of accelerated equipment wear and vicious growth in slag discharge.

[0007] In some embodiments, the coal mill material recovery system further includes a first pipeline, a gas supply pipeline, and a gas supply valve. The sorting component further includes a suction port, which is connected to the air inlet via the first pipeline. The gas supply pipeline is connected to the first pipeline and is used to connect to the outside. The gas supply valve is located on the gas supply pipeline.

[0008] In some embodiments, the coal mill material recovery system further includes a second pipe, an exhaust pipe, and an exhaust valve. The second pipe connects the air outlet of the blower and the mixer. The exhaust pipe is connected to the second pipe and is used to connect to the outside. The exhaust valve is located on the exhaust pipe.

[0009] In some embodiments, the sorting assembly further includes a first gathering portion, a second gathering portion, and a gas-solid separator. The first gathering portion is located on the side near the feed inlet, and the lower end of the first gathering portion forms the first discharge port. The second gathering portion is located on the side away from the feed inlet, and the lower end of the second gathering portion forms the second discharge port. The gas-solid separator is located at the suction port and is used to separate the combustible components carried in the negative pressure airflow. The separated combustible components flow toward the second discharge port under their own weight. The separated negative pressure airflow enters the blower through the first pipe.

[0010] In some embodiments, the mixer includes a housing, a rotary distributor, a feed pipe, a collection cylinder, and a negative pressure port. The rotary distributor is located in the middle of the housing and has a rotating shaft and a plurality of distribution bins arranged circumferentially around the rotating shaft. One end of the feed pipe is connected to the second outlet, and the other end of the feed pipe is placed inside the housing and above the rotary distributor. The collection cylinder has a first end and a second end along the axial direction, is connected to the housing, and is located below the rotary distributor. The rotary distributor rotates at a preset speed, and the plurality of distribution bins sequentially receive the combustible components conveyed by the feed pipe and transfer them into the collection cylinder. The air outlet of the blower is connected to the first end of the collection cylinder via the second pipe. The negative pressure port is located on the housing and above the rotary distributor. The negative pressure port is connected to the sorting component via a pipe so that a portion of the positive pressure airflow entering through the collection cylinder can be introduced into the sorting component by the negative pressure airflow.

[0011] In some embodiments, the recovery pipeline includes a main recovery pipeline and a plurality of recovery branch pipelines connected to the main recovery pipeline. The main recovery pipeline is connected to the second end of the collection cylinder, and the plurality of recovery branch pipelines are connected one-to-one with the coal inlets of the plurality of coal mills. Recovery valves are provided on the recovery branch pipelines.

[0012] In some embodiments, the collecting component is connected to at least one of the coal mills.

[0013] In some embodiments, there are multiple collection components, and each of the multiple collection components is connected to a corresponding coal mill.

[0014] In some embodiments, the collecting assembly has a chamber and includes a feed end, an air inlet end, and a discharge end communicating with the chamber. The feed end is connected to the slag discharge port of the coal mill via a pipe, and the discharge end is connected to the feed port of the sorting assembly. The air inlet end is used to introduce air to compensate for the internal pressure difference of the collecting device and to provide auxiliary power for the flow of the mixture within the collecting device. The feed end, the air inlet end, and the discharge end are respectively provided with a feed valve, an air inlet valve, and a discharge valve.

[0015] In some embodiments, the coal mill material recovery system further includes a pressure sensor and a control system. The pressure sensor is disposed on at least one of the second pipeline and the sorting component. The control system is communicatively connected to the blower, the air supply valve, the exhaust valve, and the pressure sensor, and is used to control the start and stop of the blower and the opening and closing of the air supply valve and / or the exhaust valve according to the signal of the pressure sensor or a preset command.

[0016] The coal mill material recovery system of this invention has the following main technical effects: 1. In terms of energy saving and consumption reduction, the system, through efficient sorting and gas-solid separators, can accurately separate and recover most of the coal particles and coal powder in the mixture, reducing fuel loss and improving the economic efficiency of boiler operation. 2. In terms of equipment protection, it avoids continuous wear of the coal mill grinding parts by hard impurities, extending their service life. Furthermore, the gas-solid separator prevents coal powder from entering the blower, protecting the safe and stable operation of the blower. 3. In terms of operation control, the system, through the design of air supply and exhaust valves and an automated control system, can flexibly switch between four working states: idling, sorting, recovery, and normal operation, intelligently adapting to various operating conditions of the coal mill.

[0017] The coal mill material recovery method of this invention is implemented by the coal mill material recovery system of any of the above embodiments, including:

[0018] Idle state: The air inlet and air outlet of the blower are both connected to the outside, the sorting component stops sorting, and stops feeding the combustible components to the coal mill; Sorting state: The air inlet of the fan is connected to the sorting component, and the air outlet is connected to the outside, so as to improve the kinetic energy of the negative pressure airflow and carry out the conveying and sorting of the mixture; Recovery state: The air inlet of the blower is connected to the outside, and the air outlet is connected to the mixer to increase the kinetic energy of the positive pressure airflow and transport the combustible components to the coal mill; Normal state: The air inlet of the blower is connected to the sorting component, the air outlet is connected to the mixer, the negative pressure airflow and the positive pressure airflow are balanced, and the mixture is conveyed and sorted at the same time, as well as the combustible components are conveyed to the coal mill.

[0019] The coal mill material recovery method of this invention achieves precise matching and flexible switching between the system's working mode and the actual operating conditions of the coal mill through four distinct working states: idling, sorting, recovery, and normal operation, combined with valve linkage control. Specifically, it enters a low-energy idling state when no operation is required; and when needed, it can flexibly choose between individual sorting and temporary storage, centralized recovery, or continuous synchronous operation. This not only significantly optimizes the system's energy consumption and avoids ineffective operation of equipment such as fans and valves, but also enables the system to easily cope with complex operating conditions such as coal mill start-up, maintenance, and load changes, ensuring that the recovery operation is always efficient, economical, and stable. Attached Figure Description

[0020] Figure 1 This is an overall schematic diagram of the coal mill material recovery system according to an embodiment of the present invention.

[0021] Figure 2This is a schematic diagram of the sorting component in the coal mill material recovery system according to an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the mixer in the coal mill material recovery system according to an embodiment of the present invention.

[0023] Figure label: 1. Collection component; 101. Feeding end; 102. Air inlet end; 103. Discharge end; 104. Feeding valve; 105. Air inlet valve; 106. Discharge valve; 2. Sorting assembly; 21. Feed inlet; 22. First discharge outlet; 23. Second discharge outlet; 24. Suction port; 25. First gathering section; 26. Second gathering section; 27. Gas-solid separator; 3. Fan; 31. Air inlet; 32. Air outlet; 4. Mixer; 41. Shell; 42. Rotary distributor; 421. Rotating shaft; 422. Distributor bin; 43. Feed pipe; 44. Collector cylinder; 441. First end; 442. Second end; 45. Negative pressure port; 5. Recycle pipelines; 51. Recycle main pipelines; 52. Recycle branch pipelines; 53. Recycle valves; 6. First pipeline; 7. Gas supply pipeline; 8. Gas supply valve; 9. Second pipeline; 10. Exhaust pipeline; 11. Exhaust valve; 12. Pressure sensor; 13. Coal mill. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] like Figures 1-3As shown, the material recovery system of the coal mill 13 in this embodiment of the invention includes a collection component 1, a sorting component 2, a blower 3, a mixer 4, and a recovery pipeline 5. It is used to receive the mixture discharged from the coal mill 13. The sorting component 2 includes an inlet 21, a first outlet 22, and a second outlet 23. The inlet 21 is connected to the collection component 1. The sorting component 2 receives the mixture from the collection component 1 and sorts the mixture, so that cobblestones are discharged from the first outlet 22 and combustible components are discharged from the second outlet 23. The air inlet 31 of the blower 3 is connected to the sorting component 2. The inlet 31 and outlet 32 ​​are connected to the outside. The mixer 4 is connected to the second outlet 23 of the sorting component 2 and the outlet 32 ​​of the blower 3. The mixer 4 is used to receive the combustible components from the second outlet 23 and mix the combustible components with the positive pressure airflow from the blower 3. The recovery pipeline 5 is located between the mixer 4 and the coal mill 13 and is used to transport the coal powder carried by the positive pressure airflow back to the coal mill 13.

[0026] The material recovery system of the coal mill 13 provided in this embodiment can effectively separate the stone coal and combustible components in the mixture discharged from the coal mill 13, and efficiently send the combustible components, especially coal powder, back to the coal mill 13 for reuse, thereby improving the coal utilization rate and reducing fuel consumption and waste residue treatment costs.

[0027] The material recovery system of the coal mill 13 in this embodiment of the invention includes a collection component 1, a sorting component 2, a blower 3, a mixer 4, and a recovery pipeline 5. The collection component 1 is used to receive the mixture of raw coal and gravel discharged from the coal mill 13. The sorting component 2 is provided with a feed inlet 21, a first discharge outlet 22, and a second discharge outlet 23, wherein the feed inlet 21 is connected to the collection component 1. The sorting component 2 sorts the fed mixture, so that the heavier gravel is discharged from the first discharge outlet 22, while the lighter combustible components (such as coal particles, coal powder, etc.) are discharged from the second discharge outlet 23.

[0028] The blower 3 has an air inlet 31 and an air outlet 32, both of which can be connected to the outside atmosphere. The air inlet 31 of the blower 3 is connected to the interior of the sorting component 2 and is used to generate a negative pressure airflow within the sorting component 2. This airflow drives the mixture from the collecting component 1 into the sorting component 2 for sorting. After passing through the blower 3, the negative pressure airflow is converted into a positive pressure airflow and discharged from the air outlet 32.

[0029] The mixer 4 is connected to the second discharge port 23 of the sorting component 2 and the air outlet 32 ​​of the blower 3. It is used to receive the combustible components discharged from the second discharge port 23 and to fully mix these components with the positive pressure airflow from the air outlet 32 ​​of the blower 3. The recovery pipeline 5 is connected between the mixer 4 and the coal mill 13. Using the kinetic energy of the positive pressure airflow, the combustible components such as coal gangue, broken coal pieces, and coal powder carried in the mixed airflow are transported back to the coal inlet of the coal mill 13 through the recovery pipeline 5, thus completing the material recovery.

[0030] The complete material flow is as follows: The mixture containing coal gangue, broken coal, coal powder, and gravel discharged from the coal mill 13 during operation first enters the collection component 1 for temporary storage and buffering. Subsequently, under the negative pressure generated by the system, the mixture is conveyed to the feed inlet 21 of the sorting component 2. Inside the sorting component 2, the mixture is sorted in the airflow and gravity field: the denser gravel settles downwards and is eventually discharged from the system through the first discharge outlet 22 as waste. The less dense combustible components (mainly coal powder and coal particles) move towards the second discharge outlet 23.

[0031] Combustible components discharged from the second discharge port 23 enter the mixer 4. Simultaneously, the positive pressure airflow generated by the blower 3 is also introduced into the mixer 4. Inside the mixer 4, the combustible components and the high-speed positive pressure airflow are thoroughly mixed and diffused, forming a gas-solid two-phase flow. This gas-solid two-phase flow, rich in combustible components, then enters the connected recovery pipeline 5. Driven by the continuous kinetic energy of the positive pressure airflow, it is directly transported back to the coal inlet of the coal mill 13 along the pipeline, thus re-entering the pulverizing system to participate in combustion, achieving closed-loop circulation and recycling of pulverized coal.

[0032] In some specific embodiments, the blower 3 is a Roots blower 3, which has a constant air volume and has the ability to deliver air by force.

[0033] In some embodiments, the coal mill 13 material recovery system further includes a first pipe 6, a gas supply pipe 7, and a gas supply valve 8. The sorting component 2 also includes a suction port 24, which is connected to the air inlet 31 via the first pipe 6. The gas supply pipe 7 is connected to the first pipe 6 and is used to connect with the outside. The gas supply valve 8 is located on the gas supply pipe 7.

[0034] This embodiment achieves its functionality through the introduction of the supplementary air pipe 7, while also providing a flexible air path adjustment method for switching the system under different operating conditions. Specifically, the sorting component 2 also includes a specially designed suction port 24. The first pipe 6 connects the suction port 24 to the air inlet 31 of the fan 3, forming the main channel for negative pressure airflow from the sorting component 2 to the fan 3. The supplementary air pipe 7 is connected to the first pipe 6, with its other end opening to the outside atmosphere. A supplementary air valve 8 is installed on the supplementary air pipe 7 to control the on / off state or opening degree of the supplementary air pipe 7.

[0035] By controlling the state of the air supply valve 8, the air supply to the blower 3 can be controlled to come from the sorting assembly 2 and the collection assembly 1 before the air separator, or directly from the outside air supply after the sorting assembly 2. This allows for the control of the start and stop of the sorting assembly 2. When the air supply valve 8 is open, since there is almost no resistance at the air supply channel, the airflow will enter from the air supply pipe 7, and the sorting assembly 2 will stop working. Conversely, when the air supply valve 8 is closed, a negative pressure airflow will be generated inside the sorting assembly 2, and the airflow carrying the mixture will flow to achieve sorting.

[0036] In some embodiments, the material recovery system of the coal mill 13 further includes a second pipe 9, an exhaust pipe 10, and an exhaust valve 11. The second pipe 9 is connected to the air outlet 32 ​​of the fan 3 and the mixer 4. The exhaust pipe 10 is connected to the second pipe 9 and is used to connect with the outside. The exhaust valve 11 is provided on the exhaust pipe 10.

[0037] In this embodiment, the second pipe 9 connects the air outlet 32 ​​of the fan 3 and the mixer 4, forming the main channel for delivering positive pressure airflow to the mixer 4. The exhaust pipe 10 is connected to the second pipe 9, and its end leads to the outside atmosphere. The exhaust valve 11 is installed on the exhaust pipe 10 to control the opening and closing of the exhaust bypass.

[0038] When only sorting is required and no recycling is needed (i.e., in sorting mode), exhaust valve 11 can be opened and the subsequent recycling path closed, allowing all the positive pressure airflow generated by fan 3 to be discharged through exhaust pipe 10 (since exhaust pipe 10 is directly connected to the outside and there is no resistance, the airflow will be discharged from here). At this time, fan 3 only provides negative pressure to sorting component 2. When the system needs to perform sorting and recycling simultaneously (i.e., in normal mode), exhaust valve 11 is closed, and all the positive pressure airflow enters mixer 4 through second pipe 9 for conveying combustible components.

[0039] In some embodiments, the sorting assembly 2 further includes a first gathering part 25, a second gathering part 26, and a gas-solid separator 27. The first gathering part 25 is located on the side near the feed inlet 21, and the lower end of the first gathering part 25 forms a first discharge port 22. The second gathering part 26 is located on the side away from the feed inlet 21, and the lower end of the second gathering part 26 forms a second discharge port 23. The gas-solid separator 27 is located at the suction port 24 and is used to separate the combustible components carried in the negative pressure airflow. The separated combustible components flow toward the second discharge port 23 under their own weight. The separated negative pressure airflow enters the blower 3 through the first pipe 6.

[0040] This embodiment significantly improves the separation efficiency and reliability of coal ash and combustible components by setting a specifically shaped converging section and a gas-solid separator 27. The introduction of the gas-solid separator 27 ensures that most combustible components can be effectively intercepted and collected, preventing them from directly entering the blower 3 with the negative pressure airflow, thus protecting the blower 3 and improving the coal powder recovery rate.

[0041] Specifically, the sorting component 2 has a first gathering section 25 on one side near its inlet 21, the lower end of which tapers to form a first outlet 22 specifically for discharging the gravel and coal. On the other side away from the inlet 21, a second gathering section 26 is provided, the lower end of which tapers to form a second outlet 23 for discharging combustible components. This gathering structure facilitates the natural aggregation and directional discharge of materials under gravity. The dimensions of the first gathering section 25 and the second gathering section 26 in the direction of negative pressure airflow can be set as needed.

[0042] The sorting assembly 2 also includes a gas-solid separator 27 located at the suction port 24. The gas-solid separator 27 separates the negative pressure airflow from the internal chamber of the sorting assembly 2 to the suction port 24, effectively separating the fine coal dust and other combustible components carried within. The separated combustible components fall under their own gravity and converge and flow towards the second discharge port 23, eventually being discharged from the second discharge port 23. The gas-solid separator 27 can be equipped with a filter screen or similar mechanical filtration equipment as needed. The separated, relatively pure negative pressure airflow is then drawn into the blower 3 through the first pipe 6, thus avoiding wear on the impeller of the blower 3 caused by a large number of solid particles and ensuring the long-term stable operation of the blower 3.

[0043] In some embodiments, the mixer 4 includes a housing 41, a rotary distributor 42, a feed pipe 43, a collection cylinder 44, and a negative pressure port 45. The rotary distributor 42 is located in the middle of the housing 41 and has a rotating shaft 421 and a plurality of distribution bins 422 arranged circumferentially around the rotating shaft 421. One end of the feed pipe 43 is connected to the second discharge port 23, and the other end of the feed pipe 43 is placed inside the housing 41 and above the rotary distributor 42. The collection cylinder 44 has a first end 441 and a second end 442 along the axial direction. The collection cylinder 44 is connected to the housing 41. The body 41 is connected and located below the rotary distributor 42. The rotary distributor 42 rotates at a preset speed. Multiple distribution bins 422 sequentially receive the combustible components conveyed by the feed pipe 43 and transfer them into the collection cylinder 44. The air outlet 32 ​​of the blower 3 is connected to the first end 441 of the collection cylinder 44 via the second pipe 9. The negative pressure interface 45 is located on the housing 41 and above the rotary distributor 42. The negative pressure interface 45 is connected to the sorting component 2 via a pipe so that part of the positive pressure airflow entering through the collection cylinder 44 can be introduced into the sorting component 2 by the negative pressure airflow.

[0044] In this embodiment, the mixer 4 not only achieves uniform and controllable mixing of combustible components and positive pressure airflow, but its unique rotary distributor 42 and local airflow circulation structure also more effectively regulate the internal pressure distribution of the mixer 4, avoid the mixing of negative pressure airflow and positive pressure airflow, prevent coal powder from escaping, and promote full contact between the gas and solid phases, making coal powder transportation more stable and continuous.

[0045] The mixer 4 mainly includes a housing 41, a rotary distributor 42, a feed pipe 43, a collection cylinder 44, and a negative pressure interface 45. The rotary distributor 42 is located in the middle of the housing 41, and its core structure consists of a rotating shaft 421 and multiple independent distribution bins 422 evenly arranged around the rotating shaft 421. One end of the feed pipe 43 is connected to the second outlet 23 of the sorting component 2, and the other end extends into the housing 41 and is located directly above the rotary distributor 42, ensuring that the falling material can be received by the distribution bins 422.

[0046] The collecting cylinder 44 has a first end 441 and a second end 442 along its axial direction. It is connected to the housing 41 and fixedly installed below the rotary distributor 42. The positive pressure airflow generated by the blower 3 is fed into the collecting cylinder 44 from the first end 441 through the second pipe 9. The rotary distributor 42 is driven by a drive device and rotates at a preset speed at a constant or intermittent speed. Its working process is as follows: when a certain distributing bin 422 rotates to below the feed pipe 43, it receives a handful of combustible components falling from the feed pipe 43. As the distributor continues to rotate, the distributing bin 422 gradually leaves the feed inlet 21 area and rotates to above the collecting cylinder 44. At this time, the coal powder in the distributing bin 422 falls into the collecting cylinder 44 below under the action of gravity, where it meets and mixes with the positive pressure airflow flowing in from the first end 441.

[0047] Specifically, a negative pressure port 45 is provided on the housing 41, located above the rotary distributor 42. This port is connected to the interior of the housing 41 (usually the upper region) via a pipe. This design creates a local airflow circulation, where a small portion of positive pressure airflow mixed in from the collecting cylinder 44 passes through the rotary distributor 42 region and enters the upper region of the housing 41. It is then guided by the suction generated by the negative pressure port 45 and drawn into the sorting assembly 2 through the pipe, where it is separated by the gas-solid separator 27. This airflow creates a slightly negative pressure environment in the upper part of the housing 41, preventing dust from overflowing from the feed inlet 21 and other points, and also sending a small amount of coal powder back to the sorting assembly 2 for secondary separation.

[0048] In some embodiments, the recovery pipeline 5 includes a main recovery pipeline 51 and a plurality of recovery branch pipelines 52 connected to the main recovery pipeline 51. The main recovery pipeline 51 is connected to the second end 442 of the collection cylinder 44. The plurality of recovery branch pipelines 52 are connected one-to-one with the coal inlets of the plurality of coal mills 13. Recovery valves 53 are provided on the recovery branch pipelines 52.

[0049] The coal mill 13 material recovery system of this embodiment of the invention, by setting up a recovery pipeline 5 with a branch structure and corresponding valves, can flexibly transport the recovered coal powder to one or more designated coal mills 13, realizing multi-point, controllable and precise recovery.

[0050] Specifically, the recovery pipeline 5 includes a main recovery pipeline 51 and multiple recovery branch pipelines 52 connected to it. The main recovery pipeline 51 is directly connected to the second end 442 of the collection cylinder 44 of the mixer 4, receiving the gas-solid two-phase flow rich in combustible components output from the mixer 4. The multiple recovery branch pipelines 52 are led out from the main recovery pipeline 51, and their ends are connected to the coal inlets of multiple coal mills 13 in the system. Each recovery branch pipeline 52 is equipped with an independent recovery valve 53.

[0051] Operators can flexibly select which one or more coal mills 13 to send pulverized coal back to by opening or closing the recovery valves 53 on specific recovery branch pipes 52, based on production needs. For example, when a single coal mill 13 is under maintenance, its corresponding branch valve can be closed to direct the pulverized coal to other operating coal mills 13. Alternatively, the recovery ratio of each branch can be dynamically adjusted according to the real-time coal feed of each coal mill 13 to achieve load balancing.

[0052] In some embodiments, the collecting component 1 is connected to at least one coal mill 13. Alternatively, there may be multiple collecting components 1, with each of the multiple collecting components 1 connected to a corresponding multiple coal mill 13.

[0053] In the coal mill 13 material recovery system of this embodiment, the collection component 1 and the coal mill 13 can be flexibly connected to adapt to different site layouts, equipment spacing, and process requirements. Whether for centralized processing or decentralized operation, the system can be adapted through modular design.

[0054] The specific configuration method is as follows: The first option is a centralized collection scheme: the system is equipped with a collection component 1, which is connected to the slag discharge ports of multiple coal mills 13 simultaneously through a pipeline network. This component is used to receive the mixture from multiple coal mills 13 and perform unified collection and buffering. This scheme is suitable for situations where the coal mills 13 are arranged compactly and space is limited, which can reduce the number of equipment and initial investment.

[0055] The second approach is a decentralized solution: the system has multiple independent collection components 1, the number of which is equal to the number of coal mills 13 that need to be serviced, and they are connected one-to-one. That is, each coal mill 13 has a dedicated collection component 1 directly connected to its slag discharge port. This solution makes the slag discharge and pretreatment processes of each coal mill 13 relatively independent, which facilitates unit-specific control, maintenance, and fault isolation. It is especially suitable for large units where the coal mills 13 are distributed or require independent operation and control.

[0056] In some embodiments, the collecting assembly 1 has a chamber and includes a feed end 101, an air inlet end 102, and a discharge end 103 communicating with the chamber. The feed end 101 is connected to the slag discharge port of the coal mill 13 via a pipe, and the discharge end 103 is connected to the feed inlet 21 of the sorting assembly 2. The air inlet end 102 is used to introduce air to compensate for the internal pressure difference of the collecting device and to provide auxiliary power for the flow of the mixture within the collecting device. The feed end 101, air inlet end 102, and discharge end 103 are respectively equipped with a feed valve 104, an air inlet valve 105, and a discharge valve 106.

[0057] The material recovery system of the coal mill 13 in this embodiment of the invention effectively solves the problems of blockage, airflow pulsation, and uneven feeding that may occur during the transfer of the mixture from the coal mill 13 to the sorting component 2. Precise valve control ensures the stability and continuity of material conveying.

[0058] The collecting assembly 1 has a buffer chamber. This chamber is connected to three key ports: a feed end 101, an air inlet 102, and a discharge end 103. The feed end 101 is directly connected to the slag discharge port of the coal mill 13 via a pipe, and is used to receive the mixture of raw coal and stone coal. The discharge end 103 is connected to the feed port 21 of the sorting assembly 2 via a pipe, and is the outlet for the mixture to leave the collecting assembly 1 and enter the sorting stage.

[0059] Specifically, the air inlet 102 is used to introduce outside air. Its core functions are twofold: first, it actively compensates for the negative pressure difference created within the collection component 1 chamber due to the suction from the downstream fan 3, preventing excessive compression of the mixture or obstruction of material flow due to excessive negative pressure; second, the introduced airflow provides additional auxiliary power for the flow of the mixture within the component and in the discharge pipe, acting as a pneumatic booster, which significantly improves the flowability, especially for damp or easily sticky materials.

[0060] To achieve precise control of material and airflow, a feed valve 104, an air inlet valve 105, and a discharge valve 106 are installed at the feed end 101, air inlet end 102, and discharge end 103, respectively. By operating these valves, the feed rate, air supply rate, and discharge speed can be flexibly adjusted. For example, when collecting the mixture, the air inlet valve 105 and discharge valve 106 can be closed, while the feed valve 104 can be opened. When discharge is required, the operation is reversed.

[0061] In some embodiments, the coal mill 13 material recovery system further includes a pressure sensor 12 and a control system. The pressure sensor 12 is located on at least one of the second pipeline 9 and the sorting component 2. The control system is communicatively connected to the blower 3, the air supply valve 8, the exhaust valve 11, and the pressure sensor 12, and is used to control the start and stop of the blower 3 and the opening and closing of the air supply valve 8 and / or the exhaust valve 11 according to the signal of the pressure sensor 12 or a preset command.

[0062] In some specific embodiments, the control system can also control the rotation state of the rotary distributor 42 in the mixer 4, and set valves at the first discharge port 22 and the second discharge port 23 of the sorting component 2 and control them through the control system, as well as control the feed valve 104, the air inlet valve 105 and the discharge valve 106 in the collection component 1, and control the recovery valve 53, and any other equipment that requires electrical control.

[0063] This embodiment achieves automated management and smooth switching of system operating status by real-time monitoring of pressure at key locations and coordinated control of fan 3 and valves.

[0064] Specifically, the system adds a pressure sensor 12 and a centralized control system. The pressure sensor 12 is arranged on the second duct 9 used to deliver positive pressure airflow, and / or on the body of the sorting component 2, to monitor the status of the positive pressure airflow or pressure changes in the sorting chamber in real time. The control system (e.g., PLC or DCS) serves as the control core and is connected to the fan 3, the air supply valve 8, the exhaust valve 11, and the pressure sensor 12 via communication lines.

[0065] The control system automatically controls the relevant equipment based on preset program logic or received operating commands, combined with real-time signals fed back from pressure sensor 12. Its core control logic includes: 1. Based on the signal from pressure sensor 12, the operating frequency (i.e., start / stop and speed) of fan 3 is automatically adjusted to maintain the negative pressure during sorting or the positive pressure during recovery within the set range. For example, when the negative pressure in sorting component 2 is insufficient, the power or speed of fan 3 is automatically increased.

[0066] 2. Based on the desired operating state of the system (such as idling, sorting, recycling, or normal), automatically control the opening and closing of the air supply valve 8 and the exhaust valve 11 to switch the airflow path.

[0067] 3. Achieve linkage with the valves on collection component 1 and recovery pipeline 5.

[0068] The following describes a material recovery method for a coal mill 13 according to an embodiment of the present invention, implemented using the material recovery system of the coal mill 13 in any of the above embodiments, including: Idle state: The air inlet 31 and air outlet 32 ​​of the blower 3 are connected to the outside, the sorting component 2 stops sorting, and stops conveying combustible components to the coal mill 13.

[0069] Sorting state: The air inlet 31 of the fan 3 is connected to the sorting component 2, and the air outlet 32 ​​is connected to the outside, so as to convey and sort the mixture.

[0070] Recovery status: The air inlet 31 of the blower 3 is connected to the outside, and the air outlet 32 ​​is connected to the mixer 4 to transport combustible components to the coal mill 13.

[0071] Normal state: The air inlet 31 of the blower 3 is connected to the sorting component 2, and the air outlet 32 ​​is connected to the mixer 4. The negative pressure airflow and the positive pressure airflow are balanced, and the mixture is conveyed and sorted at the same time, as well as the combustible components are conveyed to the coal mill 13.

[0072] Specifically, each state also includes the linkage control of the air replenishment valve 8, the exhaust valve 11, the feed valve 104, the air inlet valve 105, the discharge valve 106, and the recovery valve 53.

[0073] Idle state: Air supply valve 8 and exhaust valve 11 are open. Feed valve 104, air inlet valve 105, discharge valve 106, and recovery valve 53 can be closed. The air inlet 31 of the blower 3 is connected to the outside via the air supply pipe 7, and the air outlet 32 ​​is connected to the outside via the exhaust pipe 10. Both the sorting and recovery paths are closed. This state is typically used when the system is in standby mode, the coal mill 13 is stopped, or during equipment maintenance.

[0074] Sorting status: Air supply valve 8 is closed, and exhaust valve 11 is open. Feed valve 104 is generally open, air inlet valve 105 and discharge valve 106 are open, and recovery valve 53 can be closed or opened. The air inlet 31 of the blower 3 is connected to the sorting component 2, and the air outlet 32 ​​is connected to the outside. The mixture enters the sorting component 2 for sorting under negative pressure, and the combustible components are temporarily stored in the mixer 4 of the second collection section 26. This status is suitable for scenarios where combustible components need to be separated and temporarily stored first, but not immediately returned, such as when the coal mill 13 needs to quickly discharge slag, or when the recovery pipeline 5 needs maintenance.

[0075] Recovery Status: Air supply valve 8 is open, exhaust valve 11 is closed. Feed valve 104, air inlet valve 105, and discharge valve 106 can be opened or closed; recovery valve 53 is open. The air inlet 31 of blower 3 is connected to the outside, and the air outlet 32 ​​is connected to mixer 4. Combustible components temporarily stored in mixer 4 are returned to the coal mill 13 via recovery pipeline 5 under positive pressure airflow. This status is suitable for scenarios where combustible components temporarily stored in mixer 4 are centrally returned to the coal mill 13.

[0076] Normal state: Air supply valve 8 and exhaust valve 11 are closed, and recovery valve 53 is open. Feed valve 104, air inlet valve 105, and discharge valve 106 can be fully opened or alternately opened as needed (e.g., in feeding state: feed valve 104 is open, air inlet valve 105 and discharge valve 106 are closed; in discharge state: the opposite of feeding state). The air inlet 31 of the blower 3 is connected to the sorting component 2, and the air outlet 32 ​​is connected to the mixer 4. The system simultaneously sorts the mixture and recovers combustible components. This state is the system's standard, continuous operating mode, simultaneously performing real-time sorting of the mixture and real-time recovery of combustible components.

[0077] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0079] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0081] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0082] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A coal mill material recovery system, characterized in that, include: A collection component for receiving the mixture discharged from the coal mill; The sorting component includes an inlet, a first outlet, and a second outlet. The inlet is connected to the collection component. The sorting component is used to receive the mixture from the collection component and sort the mixture so that the gravel and coal are discharged from the first outlet and the combustible components are discharged from the second outlet. A fan, wherein the air inlet of the fan is connected to the sorting component, and is used to generate a negative pressure airflow within the sorting component to drive the flow of the mixture. After passing through the fan, the negative pressure airflow forms a positive pressure airflow at the air outlet of the fan. Both the air inlet and the air outlet can be connected to the outside. A mixer is connected to the second outlet of the sorting assembly and the outlet of the blower. The mixer is used to receive the combustible components from the second outlet and mix the combustible components with the positive pressure airflow from the blower. A recovery pipeline is provided between the mixer and the coal mill, for transporting the coal powder carried by the positive pressure airflow back to the coal mill.

2. The coal mill material recovery system according to claim 1, characterized in that, Also includes: The first pipe, the sorting component further includes a suction port, and the suction port and the air inlet are connected through the first pipe; A gas supply pipe, which is connected to the first pipe, and is used to connect to the outside world; A gas replenishment valve is provided on the gas replenishment pipeline.

3. The coal mill material recovery system according to claim 2, characterized in that, Also includes: The second pipe connects the air outlet of the fan and the mixer; An exhaust pipe, which is connected to the second pipe, is used to connect to the outside environment. An exhaust valve is provided on the exhaust pipe.

4. The coal mill material recovery system according to claim 3, characterized in that, The sorting component also includes: The first gathering part is located on the side near the feed inlet, and the lower end of the first gathering part forms the first discharge outlet; The second gathering part is located on the side away from the feed inlet, and the lower end of the second gathering part forms the second discharge outlet; A gas-solid separator is provided at the suction port to separate the combustible components carried in the negative pressure airflow. The separated combustible components flow toward the second discharge port under their own weight, and the separated negative pressure airflow enters the blower through the first pipe.

5. The coal mill material recovery system according to claim 4, characterized in that, The mixer includes: case; A rotary distributor is located in the middle of the housing, and the rotary distributor has a rotating shaft and a plurality of dispensing bins arranged circumferentially around the rotating shaft; A feeding pipe, one end of which is connected to the second discharge port, and the other end of which is placed inside the housing and above the rotary distributor; The collecting cylinder has a first end and a second end along the axial direction. The collecting cylinder is connected to the shell and located below the rotary distributor. The rotary distributor rotates at a preset speed. Multiple distributing bins sequentially receive the combustible components conveyed by the feeding pipe and transfer them into the collecting cylinder. The air outlet of the blower is connected to the first end of the collecting cylinder via the second pipe. A negative pressure interface is provided on the housing and located above the rotary distributor. The negative pressure interface is connected to the sorting component via a pipe so that a portion of the positive pressure airflow entering through the collecting cylinder can be introduced into the sorting component by the negative pressure airflow.

6. The coal mill material recovery system according to claim 5, characterized in that, The recovery pipeline includes a main recovery pipeline and multiple recovery branch pipelines connected to the main recovery pipeline. The main recovery pipeline is connected to the second end of the collection cylinder, and the multiple recovery branch pipelines are connected one-to-one with the coal inlets of the multiple coal mills. Recovery valves are provided on the recovery branch pipelines.

7. The coal mill material recovery system according to claim 1, characterized in that, The collecting component is connected to at least one of the coal mills; or There are multiple collection components, and each of the multiple collection components is connected to a corresponding coal mill.

8. The coal mill material recovery system according to claim 1, characterized in that, The collecting assembly has a chamber and includes a feed end, an air inlet end, and a discharge end communicating with the chamber. The feed end is connected to the slag discharge port of the coal mill via a pipe, and the discharge end is connected to the feed inlet of the sorting assembly. The air inlet end is used to introduce air to compensate for the internal pressure difference of the collecting device and to provide auxiliary power for the flow of the mixture in the collecting device. The feeding end, the air inlet end, and the discharge end are respectively equipped with a feeding valve, an air inlet valve, and a discharge valve.

9. The coal mill material recovery system according to claim 3, characterized in that, Also includes: A pressure sensor is disposed on at least one of the second pipe and the sorting assembly; The control system is communicatively connected to the fan, the air supply valve, the exhaust valve, and the pressure sensor, and is used to control the start and stop of the fan and the opening and closing of the air supply valve and / or the exhaust valve according to the signal from the pressure sensor or a preset command.

10. A method for recovering material from a coal mill, characterized in that, Implemented using the coal mill material recovery system according to any one of claims 1-9, comprising: Idle state: The air inlet and air outlet of the blower are both connected to the outside, the sorting component stops sorting, and stops feeding the combustible components to the coal mill; Sorting state: The air inlet of the fan is connected to the sorting component, and the air outlet is connected to the outside, so as to improve the kinetic energy of the negative pressure airflow and carry out the conveying and sorting of the mixture; Recovery state: The air inlet of the blower is connected to the outside, and the air outlet is connected to the mixer to increase the kinetic energy of the positive pressure airflow and transport the combustible components to the coal mill; Normal state: The air inlet of the blower is connected to the sorting component, the air outlet is connected to the mixer, the negative pressure airflow and the positive pressure airflow are balanced, and the mixture is conveyed and sorted at the same time, as well as the combustible components are conveyed to the coal mill.

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