Multistage separation system for fly ash

Abstract

The utility model discloses a multi-stage separation system for fly ash, which comprises an original ash silo, a first-stage ash silo, a second-stage ash silo and a third-stage ash silo, a separator is arranged at an ash feed port of the third-stage ash silo, a cyclone separator is arranged at a feed port of the first-stage ash silo, a feed port of the second-stage ash silo is communicated with an ash collecting box at the bottom of the cyclone separator through a separation guide part, and the cyclone separator is communicated with the separation guide part. The raw ash silo, the sorting machine, the cyclone separator and the fan are communicated through a conveying pipeline; a valve assembly is arranged on a discharging port of the raw ash silo and used for controlling opening and closing of the raw ash discharging port. According to the utility model, the two fine ash storerooms, namely the primary ash storeroom and the secondary ash storeroom, are arranged, and the ash collecting box arranged on the primary ash storeroom is communicated with the secondary ash storeroom through the sorting guide part, so that the sorting operation on the fine ash can be realized, and the primary fine ash and the secondary fine ash, which are different in fineness, can be sorted and collected; the coal ash can be fully and effectively utilized.

Description

Technical Field

[0001] The utility model relates to the technical field of powdery material sorting, in particular to a multi-stage sorting system for fly ash. Background Art

[0002] The large amount of fly ash produced by coal-fired power generation can be turned into treasure after classification and sorting, such as filler in cement production. After fly ash is separated by particle size, fine ash is one of the raw materials for cement production, and its economic value is greatly increased. The first-level fine ash can be directly supplied to concrete mixing stations and used as high-grade concrete raw materials to improve the fluidity of concrete; the second-level fine ash can be used as foundation cement raw materials; the remaining coarse ash can be used to make bricks or as roadbed materials.

[0003] Existing fly ash sorting devices generally only sort fly ash into two products, coarse ash and fine ash, based on the set fine ash particle size specifications, and are unable to further sort the fine ash. This results in the need to further separate the fine ash in the fine ash bin, otherwise the fly ash cannot be effectively utilized.

[0004] In view of the above-mentioned defects, the inventor of the present invention finally obtained the present invention after a long period of research and practice. Utility Model Content

[0005] To solve the above technical defects, the technical solution adopted by the utility model is to provide a multi-stage fly ash sorting system, including a raw ash bin, a primary ash bin, a secondary ash bin and a tertiary ash bin, wherein ash raw materials are placed in the raw ash bin, the primary ash bin is used to place primary fine ash, the secondary ash bin is used to place secondary fine ash, and the tertiary ash bin is used to place coarse ash. The tertiary ash feed port of the tertiary ash bin is provided with a sorting machine, the primary ash feed port of the primary ash bin is provided with a cyclone separator, the secondary ash feed port of the secondary ash bin is connected with the ash collecting box at the bottom of the cyclone separator through a sorting guide, the raw ash discharge port of the raw ash bin, the sorting machine, the cyclone separator and the fan are connected through a conveying pipeline; the raw ash discharge port of the raw ash bin is provided with a valve assembly, and the valve assembly is used to control the opening and closing of the raw ash discharge port.

[0006] Preferably, the conveying pipeline includes a first conveying pipeline, a second conveying pipeline, a connecting pipeline and a return pipeline, the output port of the fan is connected with the sorting feed port of the sorting machine through the first conveying pipeline, the raw ash discharge port of the raw ash bin is arranged on the first conveying pipeline, the output port of the fan is connected with the secondary air gate of the sorting machine through the second conveying pipeline, the coarse discharge port at the bottom of the sorting machine is connected with the tertiary ash feed port of the tertiary ash bin, the fine discharge port of the sorting machine is connected with the separation feed port of the cyclone separator through the connecting pipeline, and the gas discharge port of the cyclone separator is connected with the fan through the return pipeline, thereby forming a closed-loop conveying pipeline.

[0007] Preferably, the conveying pipeline also includes an exhaust gas pipeline, the two ends of which are respectively connected to the first conveying pipeline and the upper part of the primary ash bin, and the exhaust gas pipeline is provided with a regulating butterfly valve to control the opening and closing of the exhaust gas pipeline.

[0008] Preferably, the sorting guide portion includes an air chute pipe, both ends of which are respectively connected to the ash collecting box and the top of the secondary ash bin, and the air chute pipe is inclined from high to low from the ash collecting box to the top of the secondary ash bin.

[0009] Preferably, a blower is provided on the air chute pipe to provide transportation power for the fine ash in the air chute pipe.

[0010] Preferably, an ash collecting section is provided at the lower portion of the ash collecting box, and the ash collecting section is provided as a funnel-shaped structure with a cross-section that gradually becomes smaller from top to bottom, and the bottom of the ash collecting section is connected to the top of the primary ash bin through a first ash lower pipe, and a second ash lower pipe is provided on the side of the ash collecting section, one end of the second ash lower pipe is connected to the interior of the ash collecting section, and the other end is connected to the upper end of the air chute pipe, and the secondary fine ash in the ash collecting section enters the air chute pipe via the second ash lower pipe, and a first pneumatic gate valve is provided on the first ash lower pipe, and a second pneumatic gate valve is provided on the second ash lower pipe.

[0011] Preferably, the cyclone separator is configured as a double-stage cyclone separator, two ash collecting boxes are provided at the lower portion of the cyclone separator, the second lower ash pipe is configured as a three-way structure including two inlet sections and one outlet section, the two inlet sections respectively correspond to the two ash collecting boxes of the double-stage cyclone separator, the outlet section is connected to the upper end of the air chute pipe, and the second pneumatic gate valve is provided on the two inlet sections.

[0012] Preferably, a dust suction pipe is provided on the top of the secondary ash bin, and the dust suction pipe is configured as a U-shaped pipe. One end of the dust suction pipe is connected to the secondary ash bin, and the other end is connected to the lower end of the air chute pipe. A closable inspection and dredging hole is also provided on the dust suction pipe, and the inspection and dredging hole is configured corresponding to the lower end of the air chute pipe.

[0013] Preferably, a filter plate is provided in the ash collecting part, and the filter plate divides the interior of the ash collecting part into an upper ash chamber and a lower ash chamber distributed up and down. The filter plate is provided with filter holes, and the upper ash chamber and the lower ash chamber are connected only through the filter holes. The filter plate is arranged below the connection between the second lower ash pipe and the ash collecting part, and is arranged above the first lower ash pipe.

[0014] Preferably, a material level switch is further provided in the ash collecting box for monitoring the accumulation of the secondary fine ash in the ash upper chamber, and the material level switch is connected to the second pneumatic gate valve.

[0015] Compared with the prior art, the beneficial effect of the utility model lies in that: the utility model is provided with two fine ash bins, namely the primary ash bin and the secondary ash bin, and the ash collecting box arranged on the primary ash bin is connected with the secondary ash bin through the sorting guide part, so as to realize the sorting operation of fine ash, so as to sort and collect two kinds of fine ashes of different fineness, namely the primary fine ash and the secondary fine ash, so as to make full and effective use of fly ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural schematic diagram of the multi-stage separation system of fly ash;

[0017] Figure 2 is a structural view of the sorting guide portion;

[0018] Figure 3 A view of the connection structure of the ash collecting box;

[0019] Figure 4 It is a structural view of the sorting machine.

[0020] The numbers in the figure represent:

[0021] 1-raw ash silo; 2-first ash silo; 3-second ash silo; 4-third ash silo; 5-sorter; 6-cyclone separator; 7-fan; 8-conveying pipeline; 9-sorting guide; 11-valve assembly; 12-feeding device; 21-first ash lower pipe; 22-first pneumatic gate valve; 41-tongue plate air lock valve; 51-secondary air door; 52-raw ash inlet pipe; 53-volute; 54-fine ash outlet pipe; 55-inner cylinder ;56-coarse ash outlet pipe;57-adjusting baffle;61-ash collecting box;62-ash collecting part;63-filter plate;64-level switch;81-first conveying pipeline;82-second conveying pipeline;83-connecting pipeline;84-return pipeline;85-exhaust gas pipeline;91-air chute pipe;92-blower;93-second ash lower pipe;94-second pneumatic gate valve;95-dust suction pipe;96-inspection and dredging hole. DETAILED DESCRIPTION

[0022] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0023] Embodiment 1

[0024] like Figure 1 As shown, Figure 1 It is a structural schematic diagram of the multi-stage sorting system of fly ash; the multi-stage sorting system of fly ash of the utility model comprises a raw ash bin 1, a primary ash bin 2, a secondary ash bin 3 and a tertiary ash bin 4, the raw ash bin 1 is used to place ash raw materials, the primary ash bin 2 is used to place primary fine ash, the secondary ash bin 3 is used to place secondary fine ash, the tertiary ash bin 4 is used to place coarse ash, the tertiary ash feed port of the tertiary ash bin 4 is provided with a sorter 5, the primary ash feed port of the primary ash bin 2 is provided with a cyclone separator 6, the secondary ash feed port of the secondary ash bin 3 is connected with the ash collecting box 61 at the bottom of the cyclone separator 6 through a sorting guide part 9, and the raw ash discharge port of the raw ash bin 1, the sorter 5, the cyclone separator 6 and the fan 7 are connected through a conveying pipeline 8.

[0025] The conveying pipeline 8 includes a first conveying pipeline 81, a second conveying pipeline 82, a connecting pipeline 83 and a return pipeline 84. The output port of the fan 7 is connected to the sorting feed port of the classifier 5 through the first conveying pipeline 81. The raw ash discharge port of the raw ash bin 1 is arranged on the first conveying pipeline 81, so that the ash raw material enters the classifier 5 from the sorting feed port for coarse and fine sorting. The output port of the fan 7 is connected to the secondary air door 51 of the classifier 5 through the second conveying pipeline 82, which is used to provide sorting power for the classifier 5. The coarse discharge port at the bottom of the classifier 5 is connected to the tertiary ash feed port of the tertiary ash bin 4. The fine discharge port of the classifier 5 is connected to the separation feed port of the cyclone separator 6 through the connecting pipeline 83. The gas discharge port of the cyclone separator 6 is connected to the fan 7 through the return pipeline 84, thereby forming a closed-loop conveying pipeline 8.

[0026] The conveying pipeline 8 also includes an exhaust gas pipe 85, both ends of which are respectively connected to the first conveying pipeline 81 and the upper part of the first-level ash bin 2. The exhaust gas containing trace dust in the conveying pipeline 8 can enter the first-level ash bin 2 through the exhaust gas pipe 85, and be purified and discharged by the dust collector arranged in the first-level ash bin 2. The exhaust gas pipe 85 is provided with a regulating butterfly valve to realize the opening and closing of the exhaust gas pipe 85.

[0027] Preferably, the raw ash outlet of the raw ash bin 1 is provided with a valve assembly 11 including a manual valve, a pneumatic valve and an electric air lock, wherein the manual valve and the pneumatic valve are used to control the opening and closing of the ash raw material flowing into the first conveying pipeline 81, and the electric air lock is used to prevent the conveying gas in the first conveying pipeline 81 from being conveyed into the raw ash bin 1.

[0028] Specifically, a feeding device 12 is arranged at the lower unloading layer of the raw ash silo 1, and a manual valve / pneumatic valve and a variable frequency speed regulating electric air lock feeder are installed starting from the raw ash discharge port of the raw ash silo 1; the feeder is installed on the system pipeline, and a manual butterfly valve is installed behind the dropping point of the system pipeline as a blowing and blocking door.

[0029] Preferably, the tertiary ash feed port of the tertiary ash bin 4 is provided with a tongue plate air lock valve 41 as an air lock unloading device; the secondary air gate 51 of the classifier 5 is provided with an adjusting butterfly valve (manual / electric) to control the wind force entering the classifier 5 through the secondary air gate 51.

[0030] The ash raw material enters the first conveying pipeline 81 evenly through the manual valve, the pneumatic valve and the electric air lock, and is evenly mixed with the negative pressure airflow in the conveying pipeline 8 to form a gas-solid two-phase flow. The ash raw material enters the classifier 5 under the action of negative pressure, and is classified into coarse and fine ash under the action of gravity and centrifugal force. The classified coarse ash is discharged into the third-level ash bin 4 through the tongue plate air lock valve 41, and the fine ash is discharged from the fine discharge ports of the volutes on both sides and enters the cyclone separator 6 with the air flow for gas-ash separation. The separated fine ash falls into the ash collecting box 61, and the exhaust gas containing trace dust returns to the first conveying pipeline 81 through the return air duct, forming a closed cycle, and can enter the first-level ash bin 2 through the exhaust air duct 85 in the first conveying pipeline 81, and be purified and emptied by the dust collector arranged in the first-level ash bin 2.

[0031] The inlet of the fan 7 is provided with an adjusting damper, and the adjusting damper is equipped with an electric actuator to adjust the conveying intensity in the conveying pipeline 8 .

[0032] Generally, the cyclone separator 6 adopts a conventional double-stage cyclone separator to improve the effect of gas-ash separation. Preferably, the separator 5 generally adopts a conventional separator in the prior art.

[0033] The utility model is provided with two fine ash bins, namely the primary ash bin 2 and the secondary ash bin 3, and the ash collecting box 61 arranged on the primary ash bin 2 is connected with the secondary ash bin 3 through the sorting guide part 9, so as to realize the sorting operation of fine ash, so as to sort and collect the two kinds of fineness of fine ash, namely the primary fine ash and the secondary fine ash, so as to make full and effective use of fly ash.

[0034] Embodiment 2

[0035] like Figure 2 As shown, Figure 2 It is a structural view of the sorting guide part; the sorting guide part 9 includes an air chute pipe 91, both ends of which are respectively connected to the ash collecting box 61 and the top of the secondary ash bin 3, and the air chute pipe 91 is inclined from high to low from the ash collecting box 61 to the top of the secondary ash bin 3, so as to facilitate the movement of fine ash from the ash collecting box 61 to the secondary ash bin 3.

[0036] The air chute pipe 91 is provided with a blower 92 for providing power for the fine ash in the air chute pipe 91 so as to move the fine ash from the ash collecting box 61 to the secondary ash bin 3 in a directed manner. The conveying medium of the air chute pipe 91 is secondary fly ash (fineness is 14% to 25%).

[0037] like Figure 3 As shown, Figure 3It is a view of the connection structure of the ash collecting box; the ash collecting part 62 is arranged at the lower part of the ash collecting box 61, and the ash collecting part 62 is arranged as a funnel-shaped structure with a cross-section gradually decreasing from top to bottom, and the bottom of the ash collecting part 62 is connected with the top of the primary ash bin 2 through the first ash lower pipe 21, and the side of the ash collecting part 62 is provided with a second ash lower pipe 93, one end of the second ash lower pipe 93 is connected with the interior of the ash collecting part 62 and the other end is connected with the upper end of the air chute pipe 91, and the secondary fine ash in the ash collecting part 62 enters the air chute pipe 91 through the second ash lower pipe 93, and the first pneumatic gate valve 22 is arranged on the first ash lower pipe 21, and the second pneumatic gate valve 94 is arranged on the second ash lower pipe 93, so as to realize the opening and closing of the first ash lower pipe 21 and the second ash lower pipe 93 respectively.

[0038] Preferably, when a double-stage cyclone separator is used, two ash collecting boxes 61 are provided at the lower part of the double-stage cyclone separator, and the second ash lower pipe 93 is configured as a three-way structure, and the second ash lower pipe 93 is provided with two inlet sections and one outlet section, the two inlet sections respectively correspond to the two ash collecting boxes 61 of the double-stage cyclone separator 6, and the outlet section is connected to the upper end of the air chute pipe 91, and the two inlet sections are provided with the second pneumatic gate valve 94, so that the secondary fine ash in the two ash collecting boxes 61 can be collected independently.

[0039] A dust suction pipe 95 is arranged on the top of the secondary ash bin 3, and the dust suction pipe 95 is arranged as a U-shaped pipe. One end of the dust suction pipe 95 is connected with the secondary ash bin 3, and the other end is connected with the lower end of the air chute pipe 91. The dust suction pipe 95 is easier to discharge the conveying gas generated by the blower 92 quickly, and also reduces the blockage of the secondary fine ash at the lower end of the air chute pipe 91 to a great extent.

[0040] The dust suction pipe 95 is also provided with an inspection and dredging hole 96, which is provided corresponding to the lower end of the air chute pipe 91 and can be used to inspect and dredge the connection between the lower end of the air chute pipe 91 and the secondary ash bin 3 to avoid blockage.

[0041] The ash collecting part 62 is provided with a filter plate 63, and the filter plate 63 divides the interior of the ash collecting part 62 into an upper ash chamber and a lower ash chamber distributed up and down. The filter plate 63 is provided with a filter hole, and the upper ash chamber and the lower ash chamber are connected only through the filter hole. The filter plate 63 is arranged below the connection between the second lower ash pipe 93 and the ash collecting part 62, and is arranged above the first lower ash pipe 21. Through the filtering of the filter plate 63, the first-level fine ash with finer fineness can be filtered into the lower ash chamber, and enter the first-level ash bin 2 through the first lower ash pipe 21, while the second-level fine ash with coarser fineness cannot pass through the filter plate 63 and accumulates in the upper ash chamber, and is collected through the second lower ash pipe 93 and enters the second ash bin 3.

[0042] The ash collecting box 61 is also provided with a material level switch 64 for monitoring the accumulation of the secondary fine ash in the upper ash chamber. The material level switch 64 is connected to the second pneumatic gate valve 94. When the secondary fine ash accumulates to a certain amount in the upper ash chamber and triggers the material level switch 64, the second pneumatic gate valve 94 opens to collect the secondary fine ash. The material level switch 64 can be a conventional control switch such as a height trigger switch or a gravity trigger switch.

[0043] The structural arrangement of the sorting guide 9 can realize re-sorting of fine ash, so that the first-level fine ash and the second-level fine ash can be directly used in corresponding production, which greatly reduces the sorting cost and improves the sorting efficiency.

[0044] Embodiment 3

[0045] like Figure 4 As shown, Figure 4 It is a structural view of the sorter; the sorter 5 includes a raw ash inlet pipe 52, a volute 53, a fine ash outlet pipe 54, an inner cylinder 55, a coarse ash outlet pipe 56 and an adjusting baffle 57; the sorting feed port is arranged on the raw ash inlet pipe 52; the secondary air door 51 and the coarse discharge port are arranged on the coarse ash outlet pipe 56; the fine discharge port is arranged on the fine ash outlet pipe 54; the raw ash inlet pipe 52 is arranged in the tangential direction of the volute 53; the coarse ash outlet pipe 56 is arranged at the lower part of the volute 53; the inner cylinder 55 is concentrically arranged in the volute 53; a fine ash inlet and the fine ash outlet pipe 54 are arranged on the wall of the inner cylinder 55 along the axial direction; the interior of the volute 53 is connected with the inner cylinder 55 through the fine ash inlet; the adjusting baffle 57 is arranged between the outer wall of the inner cylinder 55 and the inner wall of the volute 53.

[0046] The adjustment angle of the adjusting baffle 57 is 0° to 45° (0° to -45°), and the fine ash sieve residue changes from fine to coarse. The secondary air door 51 is opened by the adjusting butterfly valve, and the adjustment angle is 0° to 90°, and the fine ash sieve residue changes from fine to coarse. The fine ash outlet pipe 54 is provided with a perforated plate, and the diameter of the holes on the perforated plate increases from small to large, and the fine ash sieve residue changes from fine to coarse.

[0047] Embodiment 4

[0048] The specific process of multi-stage sorting using the multi-stage sorting system of fly ash includes: a primary fine ash collection stage, a secondary fine ash collection stage and a cleaning stage. In the secondary fine ash collection stage, the exhaust gas pipeline 85 is closed, the raw ash outlet of the raw ash bin 1 is opened and fed into the first conveying pipeline 81, the ash raw material is classified into coarse and fine ash by the sorting machine 5, and the classified coarse ash is discharged into the third-stage ash bin 4 for collection, and the fine ash enters the cyclone separator 6 for gas-ash separation. The separated fine ash falls into the ash collecting box 61, the second pneumatic gate valve 94 is opened, and the first pneumatic gate valve 22 is closed, the primary fine ash enters the primary ash bin 2 through the first ash lowering pipe 21 for collection, and the secondary fine ash is accumulated in the ash collecting box 61; when the secondary fine ash accumulation in the ash collecting box 61 triggers the material level switch 64, the secondary fine ash collection stage is entered. The raw ash discharge port of the raw ash bin 1 is closed and the feeding into the first conveying pipeline 81 is stopped, the first pneumatic gate valve 22 is opened, the second pneumatic gate valve 94 is closed, and the secondary fine ash enters the secondary ash bin 3 through the air chute pipe 91 for collection; when the secondary fine ash collection stage runs to the set time, it enters the cleaning stage, the raw ash discharge port of the raw ash bin 1 is closed and the feeding into the first conveying pipeline 81 is stopped, the second pneumatic gate valve 94 is opened, the first pneumatic gate valve 22 is closed, and the exhaust gas pipeline 85 is opened to clean the tail gas containing trace dust in the conveying pipeline 8, which is purified and emptied by the dust collector arranged in the primary ash bin 2 to avoid the adverse effect of excessive dust in the tail gas on the conveying speed of the fan 7 or the conveying pipeline 8. After the cleaning stage runs to the set time, it enters the primary fine ash collection stage again.

[0049] The setting time of the secondary fine ash collection stage and the cleaning stage is generally determined based on actual production conditions, and can be adjusted accordingly based on different production conditions.

[0050] The multi-stage sorting of the fly ash by the utility model can effectively collect the primary fine ash and the secondary fine ash separately. The collection purity of the primary fine ash and the secondary fine ash is relatively high and can be directly used in the subsequent process, which is convenient for the full and effective utilization of the fly ash.

[0051] The above is only a preferred embodiment of the utility model, which is only illustrative and not restrictive. Those skilled in the art understand that many changes, modifications, and even equivalences can be made within the spirit and scope defined by the claims of the utility model, but they will all fall within the scope of protection of the utility model.

Claims

1. A multi-stage fly ash sorting system, characterized in that: It comprises a raw ash bin, a primary ash bin, a secondary ash bin and a tertiary ash bin, wherein ash raw materials are placed in the raw ash bin, the primary ash bin is used for placing primary fine ash, the secondary ash bin is used for placing secondary fine ash, the tertiary ash bin is used for placing coarse ash, the tertiary ash feed port of the tertiary ash bin is provided with a sorter, the primary ash feed port of the primary ash bin is provided with a cyclone separator, the secondary ash feed port of the secondary ash bin is connected with an ash collecting box at the bottom of the cyclone separator through a sorting guide, the raw ash discharge port of the raw ash bin, the sorter, the cyclone separator and the fan are connected through a conveying pipeline; the raw ash discharge port of the raw ash bin is provided with a valve assembly, and the valve assembly is used to control the opening and closing of the raw ash discharge port.

2. The multi-stage fly ash separation system according to claim 1, characterized in that: The conveying pipeline includes a first conveying pipeline, a second conveying pipeline, a connecting pipeline and a return pipeline. The output port of the fan is connected with the sorting feed port of the classifier through the first conveying pipeline. The raw ash discharge port of the raw ash bin is arranged on the first conveying pipeline. The output port of the fan is connected with the secondary air door of the classifier through the second conveying pipeline. The coarse discharge port at the bottom of the classifier is connected with the tertiary ash feed port of the tertiary ash bin. The fine discharge port of the classifier is connected with the separation feed port of the cyclone separator through the connecting pipeline. The gas discharge port of the cyclone separator is connected with the fan through the return pipeline, thereby forming a closed-loop conveying pipeline.

3. The multi-stage fly ash separation system according to claim 2, characterized in that: The conveying pipeline also includes an exhaust gas pipeline, the two ends of which are respectively connected to the first conveying pipeline and the upper part of the primary ash bin, and the exhaust gas pipeline is provided with a regulating butterfly valve to control the opening and closing of the exhaust gas pipeline.

4. The multi-stage fly ash separation system according to claim 3, characterized in that: The sorting guide part includes an air chute pipe, both ends of which are connected to the ash collecting box and the top of the secondary ash bin respectively, and the air chute pipe is inclined from high to low from the ash collecting box to the top of the secondary ash bin.

5. The multi-stage fly ash separation system according to claim 4, characterized in that: The air chute pipe is provided with a blower for providing transportation power for the fine ash in the air chute pipe.

6. The multi-stage fly ash separation system according to claim 4, characterized in that: An ash collecting part is arranged at the lower part of the ash collecting box, and the ash collecting part is arranged as a funnel-shaped structure with a cross-section gradually becoming smaller from top to bottom, and the bottom of the ash collecting part is connected with the top of the primary ash bin through a first ash lower pipe, and a second ash lower pipe is arranged on the side of the ash collecting part, one end of the second ash lower pipe is connected with the interior of the ash collecting part, and the other end is connected with the upper end of the air chute pipe, and the secondary fine ash in the ash collecting part enters the air chute pipe through the second ash lower pipe, and a first pneumatic gate valve is arranged on the first ash lower pipe, and a second pneumatic gate valve is arranged on the second ash lower pipe.

7. The multi-stage fly ash separation system according to claim 6, characterized in that: The cyclone separator is configured as a double-stage cyclone separator, and two ash collecting boxes are arranged at the lower part of the cyclone separator. The second lower ash pipe is configured as a three-way structure including two inlet sections and one outlet section. The two inlet sections correspond to the two ash collecting boxes of the double-stage cyclone separator respectively, and the outlet section is connected to the upper end of the air chute pipe. The second pneumatic gate valve is arranged on both inlet sections.

8. The multi-stage fly ash separation system according to claim 6, characterized in that: A dust suction pipe is arranged on the top of the secondary ash bin, and the dust suction pipe is arranged as a U-shaped pipe. One end of the dust suction pipe is connected with the secondary ash bin, and the other end is connected with the lower end of the air chute pipe. A closable inspection and dredging hole is also arranged on the dust suction pipe, and the inspection and dredging hole is arranged corresponding to the lower end of the air chute pipe.

9. The multi-stage fly ash separation system according to claim 8, characterized in that: A filter plate is provided in the ash collecting part, and the filter plate divides the interior of the ash collecting part into an upper ash chamber and a lower ash chamber distributed up and down. The filter plate is provided with filter holes, and the upper ash chamber and the lower ash chamber are connected only through the filter holes. The filter plate is arranged below the connection between the second lower ash pipe and the ash collecting part, and is arranged above the first lower ash pipe.

10. The multi-stage fly ash separation system according to claim 9, characterized in that: A material level switch is also provided in the ash collecting box for monitoring the accumulation of the secondary fine ash in the ash loading chamber, and the material level switch is connected to the second pneumatic gate valve.

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