High-precision pulse back-blowing silicon powder filtering device

Abstract

The utility model discloses a high-precision pulse back-blowing silicon powder filtering device. The device comprises a filter shell, a back-blowing assembly, a filtering assembly and an ash discharging device, and a back-blowing pipeline central gas distribution structure is adopted, so that the back-blowing effect is enhanced, and the service life of equipment is prolonged. And the shell is additionally provided with a purging opening, and the outer wall surface is additionally provided with a bin wall vibrator, so that the powder flowability is improved, the silicon powder is prevented from being stacked and bridged, and the silicon powder is ensured to be discharged smoothly. The filter element and the pattern plate are both of a double-end fixing structure, the structural stability is effectively guaranteed, and filter element damage and sealing failure caused by impact vibration of blowback airflow are prevented. A high-precision sintered metal filter element is adopted as a filter element, reduction tail gas, emptying tail gas or replacement gas is purified, it is guaranteed that no other impurities are introduced, and the product discharging quality is guaranteed. Intercepted silicon powder particles can still be recycled as system byproducts, and the good expectation of reducing cost and improving efficiency is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of filtration, in particular to a high-precision pulse back-blowing silicon powder filtering device. Background Art

[0002] In recent years, my country has steadily promoted the green and low-carbon transformation of energy, continued to promote the optimization and upgrading of industrial structure, and coordinated the promotion of carbon reduction, pollution reduction, green expansion and growth. The "dual carbon" goal has increasingly become a green engine for the high-quality development of my country's economy. As one of the representatives of new quality productivity, the photovoltaic industry has ushered in a historical development opportunity under the drive of the "dual carbon" goal. The scale of photovoltaic installed capacity has become the second largest power source in my country after coal-fired power.

[0003] As a key basic raw material for the photovoltaic industry, polysilicon is currently mainly in the form of rods and granules. Rod-shaped silicon comes from the current mainstream production process, the modified Siemens method, while granular silicon is produced by the heterogeneous deposition reaction of the fluidized bed reactor. Because both production processes involve high-purity and high-hardness silicon powder in the key links, silicon powder not only plays the role of a reactant in the system, but also becomes a source of release of microparticles, causing problems such as equipment wear and pipeline blockage, and even affecting the quality of the final product. In polysilicon production equipment, the filtration of silicon powder in the reduction tail gas and the replacement gas and circulating fluidized gas in the silicon powder transportation link is mainly bag filters, but the hard surface of amorphous silicon powder particles can easily cause abrasion and penetration of the bag, resulting in the loss of function of the filter, which in turn causes major problems such as environmental pollution and system cleanliness. The short equipment life cycle has also become a technical bottleneck restricting the long-term, stable, safe, full and excellent development of polysilicon production enterprises. Utility Model Content

[0004] The purpose of the utility model is to provide a high-precision pulse back-blowing silicon powder filtering device, which can filter and intercept silicon powder from the reduction tail gas, replacement gas, and circulating fluidized gas generated by the polysilicon production device. The clean gas after filtration can be directly discharged or recycled without introducing new impurities. The intercepted silicon powder can also be used as a system by-product, which has significant economic benefits. The filter device introduces a pulse back-blowing dust cleaning system to extend the service life of the filter, reduce the frequent disassembly and cleaning of the filter, and effectively reduce the production and operation costs.

[0005] The technical solution provided by the utility model is as follows:

[0006] A high-precision pulse back-blowing silicon powder filtering device, comprising:

[0007] The filter housing comprises an upper head, an upper cylinder, a lower cylinder and a conical head connected in sequence from top to bottom, an inlet for introducing silicon powder particle gas is arranged on the side wall below the cylinder, and an outlet is arranged on the top of the upper head;

[0008] A back-blowing assembly, comprising a back-blowing air bag, a back-blowing pipeline, an air distribution pipe, a back-blowing nozzle and a back-blowing valve, wherein the back-blowing air bag is arranged outside the filter housing, the air distribution pipe is arranged inside the upper cylinder, a plurality of the back-blowing nozzles are arranged at intervals at the bottom of the air distribution pipe, the back-blowing air bag is connected to the air distribution pipe through the back-blowing pipeline, and the back-blowing valve is arranged on the back-blowing pipeline;

[0009] A filter assembly, comprising a filter element, wherein the filter element is disposed in the lower cylinder and is used to intercept silicon powder particles in the silicon powder particle gas entering the lower cylinder;

[0010] The ash discharging device comprises a purge assembly, wherein the purge assembly comprises one or more pipelines extending into the conical head, the purge port of the purge assembly is vertically arranged downward, and the bottom of the conical head is provided with an ash discharging port.

[0011] Furthermore, the filter assembly also includes a flower plate, a grille support plate and a fixing rod. The flower plate is clamped between the upper cylinder and the lower cylinder in the horizontal direction or welded to the inside of the lower cylinder. A plurality of filter elements are arranged at equal intervals in the middle of the flower plate. Fixing rods are arranged on both sides of the lower part of the flower plate. The fixing rods and the filter elements are vertically arranged, and the grille support plate is connected between the fixing rod and the filter element.

[0012] Furthermore, the filter elements are arranged on the flower plate in a triangle, square or fan shape.

[0013] Furthermore, a differential pressure transmitter is connected to the upper and lower sides of the flower plate and between the upper cylinder and the lower cylinder.

[0014] Furthermore, it also includes a PLC controller, and the PLC controller is electrically connected to the differential pressure transmitter and the back-blow valve.

[0015] Furthermore, the outer wall surface of the conical head is evenly distributed with warehouse wall rappers.

[0016] Furthermore, the back-blowing air bag is an annular, tank-shaped or straight-cylinder structure;

[0017] The back-blowing nozzle adopts a terminal closing structure;

[0018] The back-blowing valve is a pulse solenoid valve, a pneumatic valve, a slide valve or a pulse angle valve.

[0019] Furthermore, the filter element is a sintered metal filter element with a precision of 0.5 to 10 μm, and a Venturi structure is provided at the pipe mouth of the filter element.

[0020] Furthermore, a silicon powder level monitoring device is provided at the conical head, and the silicon powder level monitoring device is installed at 1 / 2 to 2 / 3 of the total height of the conical head.

[0021] Furthermore, the number of the warehouse wall rappers is 2 to 4 groups.

[0022] Compared with the prior art, the beneficial effects of the utility model are:

[0023] The present application provides a high-precision pulse back-blowing silicon powder filtration device, which adopts a back-blowing pipeline central air distribution structure to enhance the back-blowing effect and extend the service life of the equipment. Measures such as adding a purge port to the shell and installing a silo wall vibrator on the outer wall increase the fluidity of the powder, avoid silicon powder accumulation and bridging, and ensure smooth discharge of silicon powder. Both the filter element and the flower plate adopt a double-end fixed structure to effectively ensure their structural stability and prevent damage to the filter element and seal failure caused by the impact and vibration of the back-blowing airflow. The filter element adopts a high-precision sintered metal filter element to purify the reduction tail gas, replacement gas or circulating fluidized gas to ensure that no other impurities are introduced and the quality of the product output is guaranteed. The intercepted silicon powder particles can still be recycled and reused as a by-product of the system, achieving the good expectation of reducing costs and increasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of the high-precision pulse back-blowing silicon powder filtering device provided by the utility model;

[0025] Figure 2 It is a schematic diagram of the arrangement of the filter elements in the embodiment of the utility model;

[0026] Figure 3 It is a schematic diagram of the filter assembly in the embodiment of the utility model.

[0027] The reference numerals are as follows:

[0028] 1. Lower cylinder, 2. Filter assembly, 201. Grille support plate, 202. Fixing rod, 203. Filter element, 204. Flower plate, 3. Upper cylinder, 4. Upper head, 5. Back-blowing air bag, 6. Back-blowing valve, 7. Air distribution pipe, 8. Conical head, 9. Purge assembly, 10. Silo wall vibrator, 11. Pressure differential transmitter, 12. Back-blowing nozzle, 13. Back-blowing pipeline, 14. PLC controller, 15. Inlet, 16. Outlet, 17. Ash discharge port. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the accompanying drawings is intended to represent only selected embodiments of the present application, and is not intended to limit the scope of protection claimed in the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0031] In the description of the embodiments of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present utility model can be understood according to specific circumstances.

[0032] See also Figure 1 The utility model provides a high-precision pulse back-blowing silicon powder filtering device, comprising:

[0033] The filter housing includes an upper head 4, an upper cylinder 3, a lower cylinder 1 and a conical head 8 connected in sequence from top to bottom. An inlet 15 for introducing silicon powder particle gas is provided on the side wall below the cylinder, and an outlet 16 is provided on the top of the upper head 4. The filter housing can be made of stainless steel, carbon steel or composite plate, and the inner walls of the lower cylinder 1 and the conical head 8 can be sprayed or polished to prevent silicon powder from wearing the wall surface and increasing the impurity content of silicon powder, and to maintain its good fluidity.

[0034] The back-blowing assembly includes a back-blowing air bag 5, a back-blowing pipeline 13, an air distribution pipe 7, a back-blowing nozzle 12 and a back-blowing valve 6. The back-blowing air bag 5 is arranged outside the filter housing, the air distribution pipe 7 is arranged inside the upper cylinder 3, and a plurality of back-blowing nozzles 12 are arranged at intervals at the bottom of the air distribution pipe 7. The back-blowing air bag 5 is connected to the air distribution pipe 7 through the back-blowing pipeline 13, and the back-blowing valve 6 is arranged on the back-blowing pipeline 13.

[0035] The filter assembly 2 includes a filter element 203 , which is disposed in the lower cylinder 1 and is used to intercept silicon powder particles in the silicon powder particle gas entering the lower cylinder 1 .

[0036] The ash discharge device comprises a purge assembly 9, wherein the purge assembly 9 comprises one or more pipelines extending into the conical head, the purge port of the purge assembly 9 is vertically arranged downward, and an ash discharge port 17 is arranged at the bottom of the conical head.

[0037] In this embodiment, the purge assembly 9 includes one or more pipelines extending into the conical head, and the purge port is perpendicular to the center of the device and downward. Silicon powder is compacted at the bottom of the conical head 8 due to gravity and cannot be effectively discharged. It is necessary to introduce an instantaneous purge airflow to loosen the compacted silicon powder so that it can be discharged smoothly.

[0038] The back-blowing assembly includes a back-blowing air bag 5, a back-blowing pipeline 13, an air distribution pipe 7, a back-blowing nozzle 12, and a back-blowing valve 6. The back-blowing air bag is arranged outside the filter, and its structure can be annular, tank-shaped, or straight. It is connected to the equipment through the back-blowing pipeline 13, and after passing through the upper shell of the filter, the air is distributed from the center of the air distribution pipe 7. The flow direction of the gas corresponds to the filter element channel one by one. The back-blowing nozzle 12 adopts an end closing structure to increase the gas flow rate. The back-blowing valve 6 can be selected in the form of a pulse solenoid valve, a pneumatic valve, a slide valve, a pulse angle valve, etc.

[0039] Optionally, the filter assembly 2 also includes a flower plate 204, a grille support plate 201 and a fixing rod 202, the flower plate 204 is clamped between the upper cylinder 3 and the lower cylinder 1 in the horizontal direction, and a plurality of filter elements 203 are arranged on the flower plate 204 at equal intervals, and fixing rods 202 are symmetrically arranged on the flower plates 204 on both sides of the filter elements 203, the fixing rods 202 and the filter elements 203 are both vertically arranged, and the grille support plate 201 is connected between the fixing rod 202 and the filter element 203.

[0040] In this embodiment, the structure of the filter assembly 2 is as follows: Figure 3 As shown, the filter element 203 is a sintered metal filter element, and high-precision powder mesh composite membrane filter material, metal fiber felt filter material, metal powder filter material, metal wire mesh filter material, etc. can be selected, with a precision of 0.5-10 μm. Compared with non-metallic filter materials, its high-precision filtering performance is stable, the pore size is more uniform, and the structural strength is outstanding. It is a better choice for filtering high-hardness, amorphous silicon powder particles. The flower plate 204 is generally sandwiched in the flange connecting the upper cylinder 3 and the lower cylinder 1.

[0041] The fixing rod 202 can be made of functional structural steel such as round steel, angle steel, channel steel, etc., and the connection form can be threaded or welded. The fixing rod 202 and the bottom grid support plate 201 and the upper flower plate 204 form a double-end support structure to enhance the seismic performance of the filter element 203 under backwash conditions.

[0042] Optionally, the filter elements 203 are arranged on the flower plate 204 in a triangle, square or fan shape.

[0043] The arrangement of the filter element 203 on the flower plate 204 can be in the form of a triangle, a square, a fan, etc. Figure 2 As shown, the connection with the flower plate 204 can be in the form of thread, welding, pressure plate sealing, etc.

[0044] Optionally, a differential pressure transmitter 11 is connected between the upper and lower sides of the flower plate 204 and between the upper cylinder 3 and the lower cylinder 1 .

[0045] Optionally, a PLC controller 14 is further included, and the PLC controller 14 is electrically connected to the differential pressure transmitter 11 and the back-blow valve 6 .

[0046] Optionally, the outer wall surface of the conical head 8 is evenly distributed with warehouse wall rappers 10.

[0047] Optionally, the back-blowing air bag 5 is an annular, tank-shaped or straight-cylindrical structure.

[0048] The back-blowing nozzle 12 adopts a terminal closing structure.

[0049] The back-blowing valve 6 is a pulse solenoid valve, a pneumatic valve, a slide valve or a pulse angle valve.

[0050] Optionally, the filter element 203 is a sintered metal filter element with a precision of 0.5 to 10 μm, and a Venturi structure is provided at the pipe mouth of the filter element 203 .

[0051] Optionally, a silicon powder level monitoring device is provided at the conical head 8, and the silicon powder level monitoring device is installed at 1 / 2 to 2 / 3 of the total height of the conical head.

[0052] In this embodiment, a silicon powder level monitoring device (not shown in the figure) is provided at the conical end cap 8 to determine the silicon powder accumulation height and unload the material in time. The installation height is generally set at about 1 / 2 to 2 / 3 of the total height of the conical end cap. The material level monitoring device generally uses a tuning fork level switch or an ultrasonic level meter.

[0053] Optionally, the number of the warehouse wall rappers 10 is 2 to 4 groups.

[0054] In this embodiment, the silo wall rapper 10 is of adjustable height, and has several openings on its base for installation. It is adjusted according to actual working conditions and silicon powder feeding speed, and 2 to 4 groups can be arranged circumferentially on the cone.

[0055] Working principle: The gas carrying silicon powder particles enters the cavity of the lower cylinder 1 of the filter after being buffered by the air baffle plate at the filter inlet 15. The silicon powder particles are intercepted on the surface of the filter element 203 by the filter assembly 2. The clean gas passes through the filter element 203, is discharged in the upper space of the flower plate 204, and enters the downstream system through the outlet 16. As the silicon powder particles accumulate and thicken on the surface of the filter element 203, the pressure difference between the upper and lower cavities of the filter increases. In order to ensure the long-term stable operation of the filter, when the pressure difference increases to the set value ΔP, the signal is transmitted to the backwash control system (i.e., the PLC controller 14), and the pulse backwash program is started to backwash the filter element 203 in groups online to peel off the accumulated silicon powder formed on the surface. The pulse backwash program can be set to a time mode or a pressure difference threshold mode. The backwash valve 6 works in sequence at a preset time interval, and the time interval between the valves is set to t. The time interval from the completion of all valves to the start of the next cycle is T. Both t and T can be adjusted according to actual conditions. At the same time, a discharge regulating valve is added to the ash discharge port 17 to maintain the system pressure balance. After multiple back-blowing, the amount of silicon powder accumulated in the conical space of the filter housing increases. After touching the silicon powder level monitoring switch, the discharge valve is opened and the silicon powder is discharged. In order to ensure smooth discharge of silicon powder, the outer wall of the conical head is evenly distributed with adjustable position of the silo wall vibrator 10, and its height positioning is adjusted according to the working conditions and actual operation needs.

[0056] The high-precision pulse back-blowing silicon powder filter device provided in this application adopts the back-blowing pipeline center air distribution structure to enhance the back-blowing effect and extend the service life of the equipment. The inner wall of the shell is sprayed, polished, a purge port is added, and a silo wall vibrator is installed on the outer wall to increase the fluidity of the powder, avoid the accumulation and bridging of silicon powder, and ensure the smooth discharge of silicon powder. Both the filter element and the flower plate adopt a double-end fixed structure to effectively ensure the stability of its structure and prevent damage to the filter element and seal failure caused by the impact and vibration of the back-blowing airflow. The filter element adopts a high-precision sintered metal filter element to purify the reduction tail gas, replacement gas or circulating fluidized gas to ensure that no other impurities are introduced and the quality of the product discharge is guaranteed. The intercepted silicon powder particles can still be recycled and reused as a by-product of the system, achieving the good expectation of reducing costs and increasing efficiency.

[0057] The above is only the best specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application shall be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A high-precision pulse back-blowing silicon powder filtering device, characterized in that: include: The filter housing comprises an upper head, an upper cylinder, a lower cylinder and a conical head connected in sequence from top to bottom, an inlet for introducing silicon powder particle gas is arranged on the side wall below the cylinder, and an outlet is arranged on the top of the upper head; A back-blowing assembly, comprising a back-blowing air bag, a back-blowing pipeline, an air distribution pipe, a back-blowing nozzle and a back-blowing valve, wherein the back-blowing air bag is arranged outside the filter housing, the air distribution pipe is arranged inside the upper cylinder, a plurality of the back-blowing nozzles are arranged at intervals at the bottom of the air distribution pipe, the back-blowing air bag is connected to the air distribution pipe through the back-blowing pipeline, and the back-blowing valve is arranged on the back-blowing pipeline; A filter assembly, comprising a filter element, wherein the filter element is disposed in the lower cylinder and is used to intercept silicon powder particles in the silicon powder particle gas entering the lower cylinder; The ash discharging device comprises a purge assembly, wherein the purge assembly comprises one or more pipelines extending into the conical head, the purge port of the purge assembly is vertically arranged downward, and the bottom of the conical head is provided with an ash discharging port.

2. The high-precision pulse back-flushing silicon powder filtering device according to claim 1 is characterized in that: The filter assembly also includes a flower plate, a grille support plate and a fixing rod. The flower plate is clamped between the upper cylinder and the lower cylinder in the horizontal direction or welded to the inside of the lower cylinder. A plurality of filter elements are arranged at equal intervals in the middle of the flower plate. Fixing rods are arranged on both sides of the lower part of the flower plate. The fixing rods and the filter elements are vertically arranged. The grille support plate is connected between the fixing rod and the filter element.

3. The high-precision pulse back-flushing silicon powder filtering device according to claim 2 is characterized in that: The filter elements are arranged on the flower plate in a triangle, square or fan shape.

4. The high-precision pulse back-flushing silicon powder filtering device according to claim 2 is characterized in that: A pressure differential transmitter is connected on the upper and lower sides of the flower plate and between the upper cylinder and the lower cylinder.

5. The high-precision pulse back-flushing silicon powder filtering device according to claim 4 is characterized in that: It also includes a PLC controller, which is electrically connected to the differential pressure transmitter and the back-blowing valve.

6. The high-precision pulse back-flushing silicon powder filtering device according to any one of claims 1 to 5, characterized in that: The outer wall surface of the conical head is evenly distributed with warehouse wall vibrators.

7. The high-precision pulse back-flushing silicon powder filtering device according to claim 6 is characterized in that: The back-blowing air bag is an annular, tank-shaped or straight-cylinder structure; The back-blowing nozzle adopts a terminal closing structure; The back-blowing valve is a pulse solenoid valve, a pneumatic valve, a slide valve or a pulse angle valve.

8. The high-precision pulse back-flushing silicon powder filtering device according to claim 6 is characterized in that: The filter element is a sintered metal filter element with a precision of 0.5-10 μm, and a Venturi structure is arranged at the pipe mouth of the filter element.

9. The high-precision pulse back-flushing silicon powder filtering device according to claim 7 or 8, characterized in that: The conical end cap is provided with a silicon powder level monitoring device, and the silicon powder level monitoring device is installed at 1 / 2 to 2 / 3 of the total height of the conical end cap.

10. The high-precision pulse back-flushing silicon powder filtering device according to claim 9, characterized in that: The number of the warehouse wall rappers is 2 to 4 groups.

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