A silicon powder discharging and dedusting system for trichlorosilane synthesis process

Abstract

This utility model relates to the field of polysilicon production technology and discloses a silicon powder feeding and dust removal system for the trichlorosilane synthesis process. The system consists of a receiving hopper for receiving waste silicon powder after the cold hydrogenation reaction and conveying it to a storage tank, and a filter for dust removal. A dust collection hood is installed at the inlet of the receiving hopper, and the hood has a material channel. The sidewall of the material channel has a circumferential groove with through holes. Dust removal branch pipes are inserted into the through holes, and these branch pipes are connected to the air inlet of the filter via a main dust removal pipe. The filter is then connected to a negative pressure fan via an exhaust pipe. This utility model, through the cooperation of the dust collection hood, the filter, and the connecting pipes between them, can effectively adsorb and filter dust particles generated during the feeding of waste silicon powder from the cold hydrogenation process in the trichlorosilane synthesis process. The gas discharged after filtration meets emission standards, significantly reducing the dust concentration in the operating area.

Description

Technical Field

[0001] This utility model relates to the field of polycrystalline silicon production technology, specifically to a silicon powder feeding and dust removal system for the trichlorosilane synthesis process. Background Technology

[0002] In the trichlorosilane synthesis process, due to cost considerations, the silicon powder raw material used is usually derived from waste silicon powder after cold hydrogenation reactions. This raw material is relatively dry and has a very fine particle size. Therefore, when this silicon powder is fed into the trichlorosilane synthesis process, a large amount of dust is generated due to material collisions and airflow disturbances. This not only pollutes the working environment but also poses multiple health hazards, with long-term inhalation potentially leading to silicosis.

[0003] More seriously, this process area is a dual explosion-proof work zone. The silicon powder contains a small amount of silane, which is easily ignited in air. The silicon powder-air mixture generated during dust generation, combined with silane gas, poses a risk of a combined explosion. The accompanying trace amounts of smoke also easily cause the monitored concentration of explosive gases in the work area to exceed the standard, failing to meet national safety explosion-proof standards. Furthermore, from an environmental perspective, the dust emission concentration far exceeds relevant emission standards.

[0004] Currently, there is no publicly available literature or existing technology to address the challenge of dust and explosion prevention when using cold hydrogenated waste silicon powder as a raw material in the trichlorosilane synthesis process. Summary of the Invention

[0005] This invention proposes a dust removal system for adding cold hydrogenated waste silicon powder in the trichlorosilane synthesis process, which solves the problems of dust pollution and explosion caused by the use of cold hydrogenated waste silicon powder in the trichlorosilane synthesis process.

[0006] To achieve the above-mentioned objectives, the technical solution of this utility model is as follows:

[0007] This utility model proposes a silicon powder feeding and dust removal system for the trichlorosilane synthesis process. The silicon powder feeding and dust removal system includes a receiving hopper for receiving waste silicon powder after cold hydrogenation reaction and conveying the waste silicon powder to a storage tank, and a filter for dust removal and filtration during the conveying of waste silicon powder. A dust suction hood is provided at the inlet of the receiving hopper, and a material channel is provided on the dust suction hood. The side wall of the material channel has a groove along the circumference, and a through hole is opened on the groove wall. A dust removal branch pipe is inserted in the through hole. The dust removal branch pipe is connected to the air inlet of the filter through the main dust removal pipe, and the filter is connected to a negative pressure fan through an exhaust pipe.

[0008] Preferably, the groove wall has multiple through holes, and a partition is provided between adjacent through holes.

[0009] Preferably, the dust removal branch pipe is equipped with an air intake pneumatic valve, which is connected to a nitrogen input pipe.

[0010] Preferably, the main dust removal pipeline is equipped with an explosion-proof plate.

[0011] Preferably, the filter is connected to a purging device via a purging inlet valve.

[0012] Preferably, a negative pressure regulating valve is provided on the dust removal branch pipe.

[0013] Preferably, the negative pressure fan is equipped with a silencer.

[0014] Preferably, a star-shaped discharger is provided at the discharge port of the filter.

[0015] Preferably, temperature sensors are installed at the ash hopper and discharge port of the filter.

[0016] Preferably, the ash hopper of the filter is equipped with a pneumatic vibrator.

[0017] The beneficial effects of this utility model are:

[0018] 1. This utility model, through the cooperation of a dust collection hood, a filter, and the connecting pipeline between the dust collection hood and the filter, can effectively adsorb and filter dust particles generated during the feeding of cold hydrogenation waste silicon powder in the trichlorosilane synthesis process. The gas discharged after filtration by the system meets the emission standards. After the entire system is in operation, the dust concentration in the operating area is significantly reduced.

[0019] 2. The groove on the dust collection hood of this utility model is set along the entire circumference of the dust collection hood. In conjunction with the dust collection branch pipe, it forms an annular negative pressure collection area at the feed inlet of the receiving hopper. This achieves 360° capture of dust generated during the feeding process without dead angles, significantly improving the dust capture and collection effect and suppressing dust overflow at the source. Furthermore, the formed annular negative pressure collection area can maintain a stable dust capture and collection effect, avoiding the dust collection failure problem caused by airflow disturbance in traditional single-point dust collection structures.

[0020] 3. The air inlet pneumatic valve of the dust removal branch pipe of this utility model is connected to the purging device. When the system stops, nitrogen is automatically injected into the pipeline of the system to replace the air in the system, preventing dust from absorbing moisture and causing the filter element to fail, which can significantly improve the service life of the filter.

[0021] 4. The pneumatic vibrator of the filter ash hopper of this utility model works in conjunction with the rotary valve to avoid the accumulation and agglomeration of silicon powder, thus extending the equipment operating cycle.

[0022] 5. Temperature sensors are installed in the ash hopper and discharge port of this utility model to monitor the temperature of the ash hopper (material accumulation area) and discharge port (conveying path) in different areas. When the temperature is abnormal, an alarm is triggered in time to prevent the material from spontaneously combusting.

[0023] 6. The dust collection cylinder of this utility model filter is connected to a purging device via a purging inlet valve. When the system is not working, purging gas is injected into the dust collection cylinder of the filter through the aforementioned point to replace the air, which can prevent dust from absorbing moisture. Furthermore, the pressurized gas can also purge the dust particles on the filter element, causing the dust particles deposited on the filter element to detach from the filter element surface and fall off under the action of the high-pressure airflow, thus cleaning the entire surface of the filter element.

[0024] 7. The dust removal branch pipe of this utility model is equipped with a negative pressure regulating valve. When the negative pressure in the system is large, gas can be introduced through the negative pressure regulating valve to offset part of the negative pressure, so as to prevent the pipeline from being sucked flat and deformed due to excessive negative pressure. Attached Figure Description

[0025] The foregoing and hereinafter detailed description of this utility model becomes clearer when read in conjunction with the following drawings, in which:

[0026] Figure 1 This is a schematic diagram of the silicon powder feeding and dust removal system of this utility model;

[0027] Figure 2 This is a schematic diagram of the dust cover of this utility model.

[0028] In the picture:

[0029] 1. Receiving hopper; 2. Dust hood; 3. Material channel; 4. Groove; 5. Dust removal branch pipe; 6. Dust removal main pipe; 7. Filter; 8. Negative pressure fan; 9. Inlet pneumatic valve; 10. Explosion-proof plate; 11. Purge inlet valve; 12. Negative pressure regulating valve; 13. Silencer; 14. Baffle. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of this utility model, the following will further illustrate the technical solutions for achieving the purpose of this utility model through several specific embodiments. It should be noted that the technical solutions claimed by this utility model include, but are not limited to, the following embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this utility model.

[0031] Example 1

[0032] This embodiment discloses a silicon powder feeding and dust removal system for the trichlorosilane synthesis process, as shown in the attached instruction manual. Figure 1As shown, the silicon powder addition dust removal system comprises the following two parts:

[0033] Receiver hopper 1 is used to receive waste silicon powder after cold hydrogenation reaction and transport the waste silicon powder to the storage tank; and...

[0034] Filter 7 is used for dust removal and filtration during the transportation of waste silicon powder; wherein...

[0035] A dust suction hood 2 is installed at the top edge of the feed inlet of the receiving hopper 1, such as Figure 2 As shown, the dust collection hood 2 has a through material channel 3 in the middle, which is connected to the feed inlet of the receiving hopper 1 below. The side wall of the material channel 3 is provided with a circumferential groove 4. The circumferential groove 4 forms an annular negative pressure collection area above the feed inlet of the receiving hopper 1. The groove wall of the circumferential groove 4 has a through hole, and a dust removal branch pipe 5 is installed in the through hole. The dust removal branch pipe 5 is connected to the air inlet of the filter 7 through the dust removal main pipe 6. The filter 7 is connected to the negative pressure fan 8 through the exhaust pipe.

[0036] In the embodiment described in this utility model, the filter 7 includes a dust collection cylinder and a dust hopper. An installation plate is provided inside the dust collection cylinder, and several filter elements are mounted on the installation plate. The installation plate divides the internal space of the dust collection cylinder into a clean chamber and a dust removal and filtration chamber. The clean chamber is connected to an external negative pressure fan 8 that generates negative pressure via an exhaust duct. The output end of the negative pressure fan 8 corresponds to the filter elements. The lower part of the dust collection cylinder is connected to the dust hopper, which communicates with the dust removal and filtration chamber.

[0037] When the system is running, the negative pressure fan 8 starts running. First, the feeding device transports the waste silicon powder generated by the cold hydrogenation process in the ton bag to the receiving hopper 1. The receiving hopper 1 then transfers the silicon powder to the storage tank connected to it. The silicon powder in the storage tank then enters the reactor after being pressurized and heated, and reacts with other materials in the reactor as one of the raw materials for synthesizing trichlorosilane. During the process of feeding the waste silicon powder into the receiving hopper 1, the dust collection branch pipes 5 arranged along the circumferential groove 4 of the dust collection hood 2 form a 360° annular negative pressure collection area under the action of the negative pressure fan 8, which captures the dust particles generated during the feeding process. The dust particles are sucked into the dust collection branch pipes 5 under the action of negative pressure and then carried into the dust collection main pipe 6, and then into the dust collection cylinder of the filter 7. Under the action of the filter element in the dust collection cylinder, the dust is blocked in the dust collection filter chamber of the dust collection cylinder and adhered to the filter element. The clean air enters the clean room after passing through the filter element, and then passes through the negative pressure fan 8 and the silencer 13 before being discharged in compliance with standards.

[0038] In the embodiment described in this utility model, the shape of the dust collection hood 2 matches the shape of the receiving hopper 1, and the size of the material channel 3 of the dust collection hood 2 matches the size of the feed inlet at the top edge of the receiving hopper 1, being slightly larger than the diameter of the feed inlet. In this way, the dust collection hood 2 can be directly inserted and installed at the top edge of the receiving hopper 1 through the gap fit between the material channel 3 and the feed inlet of the receiving hopper 1, without the need for an additional installation and fixing structure. This simplifies the overall structure and facilitates quick installation and disassembly.

[0039] It is understandable that the dust hood 2 and the receiving hopper 1 can be an integral structure, with the dust hood 2 being directly fixed to the top edge of the receiving hopper 1 by welding.

[0040] The dust removal branch pipe 5 is generally made of flexible hose, and the dust removal main pipe 6 is generally made of DN350 pipe. The design wind speed is above 23m / s to ensure the flow rate and avoid dust accumulation inside the pipe, which would make it difficult to clean.

[0041] Example 2

[0042] This embodiment discloses a silicon powder feeding and dust removal system for the trichlorosilane synthesis process, as described in the attached description. Figure 2 As shown, based on Embodiment 1, the circumferential groove 4 has multiple through holes on its groove wall, and a partition 14 is provided between adjacent through holes. The partition 14 separates the through holes in the groove 4, forming relatively independent air chambers. This allows the negative pressure fields of adjacent through holes to be independent and superimposed, significantly improving the dust capture effect compared to a design without partition 14. Furthermore, the presence of the partition 14 avoids airflow collision between adjacent through holes, making the dust collection velocity more stable and preventing dust escape due to airflow turbulence.

[0043] Furthermore, an air intake pneumatic valve 9 is installed on the dust removal branch pipe 5, and the air intake pneumatic valve 9 is connected to the purging device. After the system stops operating, the air intake pneumatic valve 9 is opened, automatically injecting gas into the system's pipeline for purging, replacing the air in the pipeline and equipment, and preventing dust from absorbing moisture and causing the filter element of the filter 7 to fail.

[0044] Furthermore, the dust collection cylinder of the filter 7 is connected to a purging device via a purge inlet valve 11. After prolonged operation, the filter element accumulates a significant amount of dust. To ensure the filtration and adsorption effect of the filter 7, it needs to be cleaned. Therefore, when the system stops operating, the purge inlet valve 11 is opened, and the gas in the purging device is injected into the dust collection filter chamber of the dust collection cylinder. The dust particles deposited on the filter element are detached from the filter element surface and fall off under the action of the high-pressure airflow, cleaning the entire filter element surface. The fallen dust particles are discharged from the ash hopper at the bottom of the dust collection cylinder.

[0045] It can be understood that the intake pneumatic valve 9 and the purge intake valve 11 can be connected to the same purging device. The purging gas is usually an inert gas, such as nitrogen or helium, but considering cost and availability, nitrogen is preferred as the purging gas.

[0046] Example 3

[0047] This embodiment discloses a silicon powder feeding dust removal system for the trichlorosilane synthesis process. Based on Embodiment 1 or Embodiment 2, an explosion-proof plate 10 is installed on the main dust removal pipeline 6. The explosion-proof plate 10 forms an active pressure relief protection mechanism against dust explosions. When the pressure in the pipeline is too high, the explosion-proof plate 10 immediately ruptures and releases pressure, which can reduce the risk of pipeline damage.

[0048] Example 4

[0049] This embodiment discloses a silicon powder feeding dust removal system for the trichlorosilane synthesis process. Based on any of the above embodiments, a negative pressure regulating valve 12 is provided on the dust removal branch pipe 5, which can be connected to the external atmosphere. When the negative pressure in the system is high, gas can be introduced through the negative pressure regulating valve 12 to offset part of the negative pressure, preventing the pipeline from being flattened and deformed due to excessive negative pressure.

[0050] Example 5

[0051] This embodiment discloses a silicon powder feeding and dust removal system for the trichlorosilane synthesis process. Based on any of the above embodiments, the discharge port of the filter 7 is connected to a rotary valve, and the ash hopper of the filter 7 is equipped with a pneumatic vibrator. The rotary valve at the bottom of the filter 7 continuously operates to discharge slag, ensuring that the collected silicon powder does not accumulate inside the filter 7, avoiding the risk of dust explosion. Furthermore, in conjunction with the pneumatic vibrator on the ash hopper, dust particles can be discharged more quickly.

[0052] Furthermore, temperature sensors are installed at the ash hopper and discharge port of the filter 7. These temperature sensors at both locations form a real-time dynamic self-ignition early warning system. Based on the characteristic of silicon powder containing silane, this design uses temperature sensors to monitor the temperature of the ash hopper (material accumulation area) and discharge port (conveying path) in different zones. When an abnormal temperature is detected, an immediate warning is issued, such as an audible and visual alarm, effectively preventing spontaneous combustion of materials inside the equipment.

[0053] Example 6

[0054] This embodiment discloses a silicon powder feeding and dust removal system for the trichlorosilane synthesis process, based on any of the above embodiments, such as Figure 1As shown, multiple receiving hoppers 1 are provided. Each receiving hopper 1 is equipped with a dust collection hood 2 at its inlet. The dust collection branch pipe 5 of each dust collection hood 2 is connected to the dust collection manifold, and then the dust collection manifold is connected to the dust collection main pipe 6, thus achieving the connection between each dust collection hood 2 and the filter 7.

[0055] If multiple dust collection hoods 2 are connected to the main dust collection pipe 6 via dust collection manifolds, then the negative pressure regulating valve 12 can be installed on the dust collection manifold, instead of being installed separately on each dust collection branch pipe 5. In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of this utility model.

[0056] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0057] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A dust removal system for silicon powder feeding in a trichlorosilane synthesis process, characterized in that, The system includes a receiving hopper (1) for receiving waste silicon powder after cold hydrogenation reaction and transporting the waste silicon powder to a storage tank, and a filter (7) for dust removal and filtration during the transportation of waste silicon powder. A dust suction hood (2) is provided at the inlet of the receiving hopper (1), and a material channel (3) is provided on the dust suction hood (2). The side wall of the material channel (3) has a groove (4) along the circumferential direction. A through hole is opened on the groove wall of the groove (4), and a dust removal branch pipe (5) is provided in the through hole. The dust removal branch pipe (5) is connected to the air inlet of the filter (7) through the dust removal main pipe (6). The filter (7) is connected to the negative pressure fan (8) through the exhaust pipe. The groove (4) forms a circumferential groove along the side wall of the material channel. The circumferential groove forms an annular negative pressure collection area above the inlet of the receiving hopper (1).

2. The silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, The circumferential groove has multiple through holes on its groove wall, and a partition (14) is set between adjacent through holes. A dust removal branch pipe (5) is installed in each through hole.

3. The silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, The dust removal branch pipe (5) is equipped with an air intake pneumatic valve (9), which is connected to the purging device.

4. The silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, An explosion-proof plate (10) is installed on the main dust removal pipe (6).

5. A silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, The filter (7) is connected to a purging device via a purging inlet valve (11).

6. A silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, A negative pressure regulating valve (12) is installed on the dust removal branch pipe (5).

7. A silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, The negative pressure fan (8) is equipped with a silencer (13).

8. A silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, The filter (7) is equipped with a star-shaped discharger at its discharge port.

9. A silicon powder feeding and dust removal system for the trichlorosilane synthesis process according to claim 1, characterized in that, A temperature sensor is installed at the discharge port of the filter (7).

10. A silicon powder feeding and dust removal system for a trichlorosilane synthesis process according to claim 1, characterized in that, The filter (7) is equipped with a pneumatic vibrator in its ash hopper.

Images