Silicon powder recovery system in polycrystalline silicon production
By designing a silicon powder recovery system for polysilicon production, and utilizing components such as induced draft fans and dust separators, efficient recovery and safe handling of silicon powder have been achieved. This solves the problems of incomplete silicon powder cleaning and dust generation in existing technologies, and improves the cleanliness and safety of the production environment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2026-04-10
AI Technical Summary
Existing technologies make it difficult to efficiently and safely recover silicon powder adhering to reduction furnace equipment during polysilicon production, and the cleaning process easily generates dust, affecting the production environment and safety.
A silicon powder recovery system for polysilicon production was designed, including components such as an induced draft fan, a dust separator, a main dust collection pipe, a photoelectric proximity switch, a dust collection hose, a PLC controller, an ash discharge pipe, a dust storage container, a differential pressure controller, and a pressure sensor. The system achieves efficient recovery and safe handling of silicon powder through automated control and negative pressure dust collection.
This technology enables efficient recovery of silicon powder during polysilicon production, reduces dust emissions, improves the cleanliness and safety of the production environment, and prevents safety accidents.
Smart Images
Figure CN224101453U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the polycrystalline silicon production field, specifically relates to a silicon powder recovery system in polycrystalline silicon production. BACKGROUND
[0002] Monocrystalline silicon produced by electronic grade polycrystalline silicon as raw material is the basic material of electronic information industry, and is the raw material of producing large-scale integrated circuits, semiconductor discrete components, power electronic devices. At present, more than 70% of the polycrystalline silicon production process in the world adopts the modified Siemens method. The so-called Siemens method is also known as trichlorosilane hydrogen reduction method, which is a method for generating polycrystalline silicon by chemical reaction in a reduction furnace.
[0003] In the process of preparing polycrystalline silicon rods, in addition to the main product silicon rods, silicon tetrachloride, dichlorosilane and hydrogen chloride are also generated in the reduction furnace, and silicon powder is also inevitably generated and attached to the reduction furnace bell jar bottom disc, electrode and other equipment. The characteristic of the modified Siemens method for producing polycrystalline silicon is that the reduction furnace produces silicon rods in batches, and after producing a batch of silicon rod products, the silicon core is reinstalled and production is resumed. Therefore, cleaning and recycling silicon powder is a very important link in production.
[0004] The silicon rods in the reduction plant need to be cooled in the air, and exposure for a certain period of time is required. During the loading process in the reduction plant, dust cannot be generated. Therefore, the reduction plant must be a clean plant. However, after the silicon rods are removed, the bell jar can be moved to a special facility for cleaning, but the bottom disc and the electrode can only be cleaned on site. Ordinary cleaning tools and facilities are difficult to recover silicon powder and are easy to generate dust, or cannot completely clean the reduction plant at one time. For example, the mobile small dust collector equipment is in the room, the cleaning frequency is high, and the transportation is not convenient. UTILITY MODEL CONTENTS
[0005] The utility model aims at providing a silicon powder recovery system in polycrystalline silicon production.
[0006] The utility model is implemented by the following technical schemes:
[0007] A silicon powder recovery system in polycrystalline silicon production, comprising an induced draft fan, a dust separator, a dust suction main pipeline, a photoelectric proximity switch, a dust suction hose, a PLC controller, an ash outlet pipe, a dust storage device, a differential pressure controller, an air pressure sensor and a purge pipe.
[0008] The air inlet of the air blower is connected with the air outlet of the dust separation device, the air inlet of the dust separation device is connected with one end of the main dust suction pipe, the other end of the main dust suction pipe is closed, a plurality of photoelectric proximity switches are arranged on the main dust suction pipe, the dust suction hose is movably connected to the interface of any photoelectric proximity switch, the signal output end of the photoelectric proximity switch is connected with the signal input end of the PLC control, and the PLC control is electrically connected with the air blower.
[0009] The bottom ash outlet of the dust separation device is connected with the dust storage device through the ash discharge pipe, and a star-shaped ash discharge valve is arranged on the ash discharge pipe.
[0010] One end of the blowing pipe is connected with the blowing pipe in the dust separation device, a blowing electric control valve is arranged on the blowing pipe, the air inlets and air outlets of the dust separation device are each provided with the air pressure sensor, the signal output end of the air pressure sensor is connected with the signal input end of the pressure difference controller, and the pressure difference controller is electrically connected with the blowing electric control valve.
[0011] Preferably, a filter screen is arranged between the air inlets and air outlets of the dust separation device, and the blowing pipe is arranged above the filter screen.
[0012] Preferably, one side of the dust storage device is provided with the contact of the temperature detector.
[0013] The dust separation device is connected with the air blower, the dust separation device is connected with the main dust suction pipe, the main dust suction pipe is closed at one end, a plurality of photoelectric proximity switches are arranged on the main dust suction pipe, the dust suction hose is movably connected to the interface of any photoelectric proximity switch, the signal output end of the photoelectric proximity switch is connected with the signal input end of the PLC control, and the PLC control is electrically connected with the air blower.
[0014] The air pressure changes of the air inlets and air outlets of the dust separation device are monitored, and when the air pressure changes obviously, the blowing pipe can be automatically blown to clean the filter screen.
[0015] The temperature of the dust storage device is monitored, and when the silicon powder in the dust storage device is deposited too much, the trace chlorosilane in the silicon powder is combusted due to other reasons, the temperature is abnormally detected in time, and the safety accident can be handled in time. BRIEF DESCRIPTION OF DRAWINGS
[0016] In order to more clearly illustrate the technical scheme in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or the prior art description, and obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from these drawings without creating labor.
[0017] Figure 1 is a schematic diagram of the overall structure of the utility model.
[0018] In the drawing: induced draft fan 1, dust separation device 2, filter screen 2.1, blowing pipe 2.2, dust suction main pipeline 3, photoelectric proximity switch 4, dust suction hose 5, PLC control 6, ash outlet pipe 7, dust storage device 8, star-shaped ash discharge valve 9, blowing pipe 10, blowing electric control valve 11, air pressure sensor 12, differential pressure controller 13, temperature measuring instrument 14, reaction furnace 15. DETAILED DESCRIPTION
[0019] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.
[0020] As shown in Figure 1 A silicon powder recovery system in polycrystalline silicon production, including induced draft fan 1, dust separation device 2, dust suction main pipeline 3, photoelectric proximity switch 4, dust suction hose 5, PLC control 6, ash outlet pipe 7, dust storage device 8, differential pressure controller 13, air pressure sensor 12, blowing pipe 10, the inside of dust separation device 2 is equipped with filter screen 2.1 between air inlet and air outlet,
[0021] The air inlet of induced draft fan 1 is connected with the air outlet of dust separation device 2, the air inlet of dust separation device 2 is connected with one end of dust suction main pipeline 3, the other end of dust suction main pipeline 3 is closed, a plurality of photoelectric proximity switches 4 are arranged on dust suction main pipeline 3, dust suction hose 5 is movably connected to the interface of any photoelectric proximity switch 4, the signal output end of photoelectric proximity switch 4 is connected with the signal input end of PLC control 6, and PLC control 6 is electrically connected with induced draft fan 1.
[0022] The induced draft fan 1 is started to suck air, so that the inside of dust separation device 2 and dust suction main pipeline 3 is under negative pressure, one, multiple or all photoelectric proximity switches 4 on dust suction main pipeline 3 are started, dust suction hose 5 is connected to the corresponding photoelectric proximity switch 4, dust separation device 2 can suck dust through dust suction hose 5 and dust suction main pipeline 3, and the air sucked by induced draft fan 1 is discharged from the air outlet thereof.
[0023] Dust suction hose 5 is convenient to move, pull and adjust position, and is convenient to use; after dust suction hose 5 is connected to any photoelectric proximity switch 4, the photoelectric proximity switch 4 is triggered to start by dust suction hose 5, and a signal is sent to PLC control 6, so that PLC control 6 controls induced draft fan 1 to start, and the equipment can be stopped during normal non-dust removal to protect the equipment and reduce use wear.
[0024] The bottom dust outlet of the dust separator 2 is connected with the dust storage 8 through a dust discharge pipe 7, and a star-shaped dust discharge valve 9 is arranged on the dust discharge pipe 7;
[0025] The silicon powder separated by the dust separator 2 is temporarily stored in the dust storage 8 through the dust discharge pipe 7, the bottom of the dust storage 8 is provided with an outlet, and the star-shaped dust discharge valve 9 is also called a star-shaped discharger, which is a special discharging device and is mainly used at the discharging port working under negative pressure.
[0026] One end of the blowing pipe 10 is connected with a blowing pipe 2.2 in the dust separator 2, the blowing pipe 2.2 is arranged above a filter screen 2.1, a blowing electric control valve 11 is arranged on the blowing pipe 10, air pressure sensors 12 are arranged on the air inlet and the air outlet of the dust separator 2, the signal output ends of the air pressure sensors 12 are connected with the signal input ends of a pressure difference controller 13, and the pressure difference controller 13 is electrically connected with the blowing electric control valve 11.
[0027] Nitrogen gas is blown through the blowing pipe 10, the blowing electric control valve 11 is opened, the nitrogen gas can blow the filter screen 2.1 in the dust separator 2 from the blowing pipe 2.2, and the filter screen 2.1 is cleaned; the air pressure sensors 12 monitor the air pressure changes of the air inlets and outlets of the dust separator 2, when the pressures of the two are equal or the difference is within a preset proper range, it is indicated that the negative pressure in the dust separator 2 is normal for dust removal, when the pressure difference is large and exceeds a preset maximum value, it is indicated that the negative pressure in the dust separator 2 is weak and cannot normally remove dust, and it is indicated that the filter screen 2.1 is blocked and needs to be cleaned, at this time, the blowing electric control valve 11 can also be opened through a signal to automatically blow.
[0028] One side of the dust storage 8 is provided with the contact of a temperature detector 14, the temperature detector 14 monitors the temperature of the dust storage 8, when too much silicon powder is deposited in the dust storage 8, trace chlorosilane in the silicon powder is combusted due to other reasons, the temperature is abnormally detected in time, and the safety accident can be treated in time.
[0029] Working principle: when the dust collector is used, any photoelectric proximity switch 4 is connected with the dust suction hose 5, is triggered and opened by the dust suction hose 5, and a signal is given to the PLC control 6, the PLC control 6 controls the starting of the induced draft fan 1, the induced draft fan 1 sucks air, the inside of the dust separator 2 and the dust suction main pipeline 3 are under negative pressure, the dust suction hose 5 is used to remove dust from the reduction furnace 15 in the reduction plant and the surrounding area, dust is sucked into the dust separator 2 through the dust suction hose 5 and the dust suction main pipeline 3, and the air sucked by the induced draft fan 1 is discharged from the air outlet thereof.
[0030] The dust is separated by the filter screen 2.1 of the dust separator 2 and settled to the bottom, the star-shaped dust valve 9 is opened, and the dust is temporarily stored to the dust storage 8 through the dust discharge pipe 7, the dust storage 8 is provided with an outlet at the bottom, and the silicon powder can be transferred in the later period, so that the silicon powder is recycled.
[0031] The air pressure sensor 12 monitors the air pressure changes of the air inlet and air outlet of the dust separator 2, when the pressure of the two is equal or the difference is within a proper range, it indicates that the negative pressure in the dust separator 2 is normal for dust removal, when the pressure difference is large and exceeds the preset maximum value, it indicates that the negative pressure in the dust separator 2 is weak and cannot normally remove dust, which indicates that the filter screen 2.1 is blocked and needs to be cleaned, at this time, a signal is given to open the blowing electric control valve 11, the blowing pipe 10 is connected with nitrogen, the nitrogen blows the filter screen 2.1 in the dust separator 2 from the blowing pipe 2.2, and the filter screen 2.1 is cleaned.
[0032] The induced draft fan 1 is a variable frequency fan, when the photoelectric control switch 4 is opened, the dust separator 2 is started, with the increase of the number of the opened photoelectric control switch 4, the motor frequency of the induced draft fan 1 can be adjusted to maintain effective negative pressure dust removal wind power.
[0033] The temperature measuring instrument 14 monitors the temperature of the dust storage 8, when the silicon powder in the dust storage 8 is too much, the trace chlorosilane in the silicon powder is combusted due to other reasons, the temperature is abnormally detected in time, and the safety accident can be handled in time.
[0034] The above only describes the preferred embodiment of the utility model, and does not limit the utility model, any modification, equivalent replacement, improvement, etc. within the spirit and principle of the utility model should be included in the protection scope of the utility model.
Claims
1. A silicon powder recovery system in polysilicon production, characterized by, The dust collector comprises an air suction fan, a dust separation device, a main dust suction pipe, a photoelectric proximity switch, a dust suction hose, a PLC controller, a dust discharge pipe, a dust storage device, a differential pressure controller, an air pressure sensor and a blowing pipe. The air inlet of the air suction fan is connected with the air outlet of the dust separation device, the air inlet of the dust separation device is connected with one end of the main dust suction pipe, the other end of the main dust suction pipe is closed, a plurality of photoelectric proximity switches are arranged on the main dust suction pipe, the dust suction hose is movably connected with the interface of any photoelectric proximity switch, the signal output end of the photoelectric proximity switch is connected with the signal input end of the PLC controller, and the PLC controller is electrically connected with the air suction fan. The dust discharge pipe is connected with the dust storage device through a dust discharge outlet at the bottom of the dust separation device, and a star-shaped dust discharge valve is arranged on the dust discharge pipe. One end of the blowing pipe is connected with a blowing pipe in the dust separation device, a blowing electric control valve is arranged on the blowing pipe, the air inlets and air outlets of the dust separation device are provided with the air pressure sensors, the signal output end of the air pressure sensor is connected with the signal input end of the differential pressure controller, and the differential pressure controller is electrically connected with the blowing electric control valve.
2. The silicon powder recovery system in a polysilicon production according to claim 1, wherein: A filter screen is arranged between the air inlets and air outlets of the dust separation device.
3. The silicon powder recovery system in a polysilicon production according to claim 1, wherein: One side of the dust storage device is provided with the contact of a temperature measuring instrument. The dust storage device is provided with the contact of a temperature measuring instrument.