Silica powder feeding system

Abstract

The utility model provides a silicon powder feeding system and relates to the field of polycrystalline silicon production. Comprising a vibration screening bin, a micro silicon powder bin, a silicon powder bin, a low-pressure bin and a high-pressure bin, a micro silicon powder outlet of the vibration screening bin is connected with a feeding port of the micro silicon powder bin, and a silicon powder outlet of the vibration screening bin is connected with a feeding port of the silicon powder bin; a discharge hole of the micro silicon powder bin is connected to a trichlorosilane synthesis device; a discharging port of the silicon powder bin is connected with a feeding port of the low-pressure bin, a discharging port of the low-pressure bin is connected with a feeding port of the high-pressure bin, and the high-pressure bin is used for being connected with a cold hydrogenation reaction device. Silicon powder and micro silicon powder can be screened and are respectively used for a cold hydrogenation reaction device and a trichlorosilane synthesis device, so that the conversion efficiency of a cold hydrogenation furnace is improved, the equipment failure rate is reduced, the frequency of pipeline cleaning and equipment maintenance is reduced, and the abrasion of equipment and pipelines is reduced; and meanwhile, the utilization efficiency of the silicon raw material can be improved, and the slag slurry treatment capacity is reduced, so that the operation burden of a slag slurry system is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the polycrystal silicon production field, specifically, relate to a kind of silicon powder feeding system. BACKGROUND

[0002] Improved Siemens method is the leading technology for producing polycrystalline silicon in the world. The technology purifies industrial silicon to electronic-grade polycrystalline silicon through a series of physical and chemical processes. Among them, the cold hydrogenation step is the core link of the improved Siemens method, which involves introducing industrial silicon powder into a hydrogenation reaction furnace for hydrogenation reaction. The trichlorosilane generated by the reaction is purified and used as raw material for the reduction step, and finally converted into high-purity silicon material. In addition, the materials generated by the side reaction can be recycled and reused.

[0003] However, in the cold hydrogenation reaction furnace, micro-silicon powder is difficult to participate in the reaction and will be carried out of the reactor with the product mixed gas, so it is discharged to the slag slurry treatment process for treatment. Since the silicon powder formed after grinding of industrial silicon has a wide particle size distribution range, it contains a certain proportion of micro-silicon powder and silicon powder with a particle size larger than micro-silicon powder. These micro-silicon powders reduce the conversion rate during the cold hydrogenation reaction, and their presence also blocks the subsequent pipelines and equipment, thereby increasing the equipment failure rate, the wear rate of equipment and pipelines, and the frequency of pipeline cleaning and equipment maintenance. SUMMARY

[0004] The purpose of the present utility model is to provide a silicon powder feeding system that can screen silicon powder and micro-silicon powder and use them separately in a cold hydrogenation reaction device and a trichlorosilane synthesis device, thereby improving the conversion efficiency of the cold hydrogenation furnace, reducing the equipment failure rate, reducing the frequency of pipeline cleaning and equipment maintenance, and reducing the wear of equipment and pipelines. At the same time, it can also improve the utilization efficiency of silicon raw materials and reduce the amount of slag slurry treatment, thereby reducing the operating burden of the slag slurry system.

[0005] To solve the above technical problems, the utility model adopts the technical scheme of:

[0006] A silicon powder feeding system includes a vibrating screening bin, a micro-silicon powder bin, a silicon powder bin, a low-pressure bin, and a high-pressure bin. The vibrating screening bin is provided with at least one outlet for micro-silicon powder, which is connected to the inlet of the micro-silicon powder bin. The vibrating screening bin is provided with at least one outlet for silicon powder, which is connected to the inlet of the silicon powder bin. The outlet of the micro-silicon powder bin is connected to the trichlorosilane synthesis device. The outlet of the silicon powder bin is connected to the inlet of the low-pressure bin. The outlet of the low-pressure bin is connected to the inlet of the high-pressure bin, which is used to heat and dry the silicon powder before sending it to the high-pressure bin. The outlet of the high-pressure bin is connected to the cold hydrogenation reaction device, which is used to pressurize the silicon powder before pushing it into the cold hydrogenation reaction device.

[0007] Further, in the utility model, the top overflow port of the silicon powder storage tank and the top overflow port of the vibrating sieve bin are respectively communicated to the top of the micro-silicon powder bin through micro-silicon powder pipelines, the top of the silicon powder storage tank and the discharge port of its bottom are communicated with nitrogen gas conveying pipelines, and the top of the vibrating sieve bin and the micro-silicon powder outlet of its bottom are communicated with nitrogen gas conveying pipes.

[0008] Further, in the utility model, the top overflow port of the silicon powder storage tank and the top overflow port of the vibrating sieve bin are respectively communicated to the top of the micro-silicon powder bin through micro-silicon powder pipelines, the top of the silicon powder storage tank and the discharge port of its bottom are communicated with nitrogen gas conveying pipelines, and the top of the vibrating sieve bin and the micro-silicon powder outlet of its bottom are communicated with nitrogen gas conveying pipes.

[0009] Further, in the utility model, the top of the micro-silicon powder bin is connected with a first dust collector, and the input pipeline and the output pipeline of the first dust collector are connected to the top of the micro-silicon powder bin.

[0010] Further, in the utility model, the top of the low-pressure bin is connected with a second dust collector, and the input pipeline and the output pipeline of the second dust collector are connected to the top of the low-pressure bin.

[0011] Further, in the utility model, the top of the high-pressure bin is connected with a third dust collector, and the input pipeline and the output pipeline of the third dust collector are connected to the top of the high-pressure bin.

[0012] Further, in the utility model, the discharge port of the low-pressure bin is connected with a hot nitrogen gas conveying pipe.

[0013] Further, in the utility model, the vibrating sieve bin is provided with a high-frequency vibration device and a vibrating sieve, the high-frequency vibration device is used for vibrating the vibrating sieve, and the vibrating sieve is detachably connected in the vibrating sieve bin.

[0014] Further, in the utility model, the micro-silicon powder outlet of the vibrating sieve bin is located at the bottom of the vibrating sieve bin, and the silicon powder outlet of the vibrating sieve bin is obliquely arranged on the inclined side wall of the vibrating sieve bin close to the bottom.

[0015] The utility model has at least the following advantages or beneficial effects:

[0016] The utility model discloses a vibrating screen divides the bin and is connected with the micro silica powder outlet of vibrating screen divides the bin and the feed inlet of micro silica powder bin, and the silica powder outlet of vibrating screen divides the bin is connected with the feed inlet of silica powder bin, can divide the silica powder of different particle size, and the silica powder of the particle size of micro silica powder is screened, and the silica powder of the particle size of micro silica powder is screened, and the micro silica powder is passed into micro silica powder bin, and the silica powder of the particle size of a little bit is passed into silica powder bin, the micro silica powder bin is connected with trichlorosilane synthesis device, and the micro silica powder is directly transported to trichlorosilane synthesis device and is synthesized, the outlet of silica powder bin is connected with the feed inlet of low pressure bin, and the silica powder is sent into low pressure bin and is heated and dried, and the air and moisture in the silica powder are excluded, to ensure that the subsequent cold hydrogenation reaction is carried out smoothly, the discharge outlet of low pressure bin is connected with the feed inlet of high pressure bin, and is used for sending the silica powder after heating and drying into high pressure bin, and the discharge outlet of high pressure bin is used for being connected with cold hydrogenation reaction device, and the silica powder is pressed to reach the powder pressure and is pushed into the cold hydrogenation reaction device and is handled, the silica powder and micro silica powder can be screened and be used in cold hydrogenation reaction device and trichlorosilane synthesis device respectively, and the conversion efficiency of cold hydrogenation furnace can be improved, the equipment failure rate is reduced, the frequency of pipeline cleaning and equipment maintenance is reduced, and the wear and tear of equipment and pipeline is reduced, and the utilization efficiency of silica raw material can be improved, and the slag slurry processing capacity is reduced, thereby reducing the operation burden of slag slurry system. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the following will be briefly introduced the drawings needed to be used in the embodiment, should understand, the following drawings only shows some embodiments of the utility model, therefore should not be regarded as the limitation to the scope, for the ordinary skilled person in the art, under the premise of not paying the creative labor, can also obtain other related drawings according to these drawings.

[0018] Figure 1 The structure block diagram of the silica powder feeding system provided for the application embodiment.

[0019] Fig. 1 - silica powder tank car, 2 - silica powder storage tank, 3 - vibrating screen divides the bin, 4 - micro silica powder bin, 5 - silica powder bin, 6 - low pressure bin, 7 - high pressure bin, 8 - first dust collector, 9 - second dust collector, 10 - third dust collector, 11 - micro silica powder pipeline. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantage of the embodiments of the utility model more clear, the following will be combined with the drawings in the embodiments of the utility model, and the technical scheme in the embodiments of the utility model is described clearly and completely, obviously, the described embodiment is a part of the embodiment of the utility model, instead of all the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of the application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application. Embodiments

[0022] Please refer to Figure 1 , which is a structural schematic diagram of a silicon powder feeding system in an embodiment of the present application.

[0023] The present embodiment provides a silicon powder feeding system, which comprises a vibrating sieve bin 3, a micro-silicon powder bin 4, a silicon powder bin 5, a low-pressure bin 6 and a high-pressure bin 7. At least one vibrating sieve bin 3 is provided. The micro-silicon powder outlet of the vibrating sieve bin 3 is connected to the feeding port of the micro-silicon powder bin 4, and the silicon powder outlet of the vibrating sieve bin 3 is connected to the feeding port of the silicon powder bin 5. The discharge port of the micro-silicon powder bin 4 is connected to a trichlorosilane synthesis device. The discharge port of the silicon powder bin 5 is connected to the low-pressure bin 6 and the high-pressure bin 7 in sequence, and then connected to a cold hydrogenation reaction device.

[0024] In the following, a silicon powder feeding system according to the present exemplary embodiment will be further described.

[0025] In some embodiments of the present application, with reference to Figure 1 The silicon powder feeding system according to the present embodiment further comprises a silicon powder tank car 1 and a silicon powder storage tank 2. The silicon powder tank car 1 transports the silicon powder to the system and directly feeds the silicon powder into the silicon powder storage tank 2. The discharge port of the silicon powder storage tank 2 is connected to the top feeding port of the vibrating sieve bin 3 through a conveying pipeline, so as to convey the silicon powder to the vibrating sieve bin for vibrating screening. The silicon powder of different particle sizes is screened, mainly into micro-silicon powder and silicon powder with a particle size larger than that of the micro-silicon powder. The micro-silicon powder has a particle size of less than 1 micrometer (μm), and the silicon powder has a particle size of 1-10 micrometers (μm). The micro-silicon powder has a small particle size and is difficult to participate in the cold hydrogenation reaction. Therefore, it is screened out before the reaction, which can improve the reaction conversion rate of the cold hydrogenation reaction device, and also can avoid the blockage of the pipeline and other equipment caused by the micro-silicon powder.

[0026] In some embodiments of the present application, the micro-silicon powder outlet of the vibrating screening bin 3 is connected to the feed inlet at the top of the micro-silicon powder bin 4, and the screened micro-silicon powder is fed into the micro-silicon powder bin 4; the silicon powder outlet of the vibrating screening bin 3 is connected to the feed inlet at the top of the silicon powder bin 5, and the screened silicon powder is fed into the silicon powder bin 5; and the two kinds of silicon powder with different particle sizes are stored in two different bins. The discharge outlet of the micro-silicon powder bin 4 is connected to the trichlorosilane synthesis device, and the micro-silicon powder in the micro-silicon powder bin 4 is directly transported to the trichlorosilane synthesis process for use, which can improve the utilization rate of raw materials; the discharge outlet of the silicon powder bin 5 is connected to the feed inlet of the low-pressure bin 6, and the stored silicon powder is fed into the low-pressure bin 6 for heating and drying treatment to remove water and air in the silicon powder; the discharge outlet of the low-pressure bin 6 is connected to the feed inlet of the high-pressure bin 7, and the dried silicon powder is fed into the high-pressure bin 7, which can pressurize the silicon powder to a predetermined pressure; and the discharge outlet of the high-pressure bin 7 is used to be connected to the cold hydrogenation reaction device, and the silicon powder after being pressurized by the high-pressure bin 7 is fed into the cold hydrogenation reaction device for cold hydrogenation reaction.

[0027] It should be noted that the low-pressure bin 6 has a pressure value of 0.3 MPa, and the high-pressure bin 7 has a pressure value higher than that of the cold hydrogenation reaction device (3.0 MPa). When the low-pressure bin 6 feeds into the high-pressure bin 7, the feed valve to the cold hydrogenation reaction device needs to be closed for pressure relief, and the pressure value after pressure relief needs to be less than that of the low-pressure bin 6, so that the material can smoothly enter the high-pressure bin 7. After the silicon powder is treated by the low-pressure bin 6 and the high-pressure bin 7, the silicon powder is transported to the cold hydrogenation reaction device for reaction after reaching the powder pushing condition, thereby improving the conversion rate of the cold hydrogenation device. At the same time, most of the micro-silicon powder is removed before entering the cold hydrogenation reactor, reducing the flow of micro-silicon powder in the hydrogenation system, reducing the failure rate caused by equipment blockage due to micro-silicon powder, reducing the cleaning frequency of the pipeline, reducing the wear of the equipment and the pipeline, and reducing the processing amount of the slurry treatment, thereby reducing the processing cost.

[0028] As a preferred embodiment, the vibrating screening bin 3 can be arranged according to the use condition, and can supply the silicon powder required by the cold hydrogenation reaction device, i.e., matching the demand of the cold hydrogenation reaction device with the processing capacity of the vibrating screening bin, while leaving a certain amount for maintenance of the vibrating screening bin. The vibrating screening bin 3 is provided with a high-frequency vibrating device and a vibrating screen, and the high-frequency vibrating device is used to vibrate the vibrating screen. The internal structure can adopt the vibrating screening device specially used for silicon powder screening in the prior art. The vibrating screen is detachably connected in the vibrating screening bin 3, and the vibrating screen can be replaced according to the demand or use condition, and the mesh number of the vibrating screen can be selected according to the need.

[0029] As a preferred embodiment, the micro-silicon powder outlet of the vibrating screening bin 3 is located at the bottom of the vibrating screening bin 3, and the silicon powder outlet of the vibrating screening bin 3 is obliquely arranged on the inclined side wall of the vibrating screening bin 3 close to the bottom. The silicon powder outlet with larger particle size is obliquely arranged on the inclined side wall of the bottom of the vibrating screening bin 3, and the silicon powder is then conveyed to the silicon powder bin 5 through the conveying pipeline. In the process of vibrating conveying along the outlet inclined surface, the micro-silicon powder with smaller particle size mixed therein can continue to fall from the gap to the micro-silicon powder outlet at the bottom of the vibrating screening bin 3, and then be sent to the micro-silicon powder bin 4 through the conveying pipeline, so that the silicon powder and the micro-silicon powder can be more efficiently screened.

[0030] As a preferred embodiment, the top overflow port of the silicon powder storage tank 2 and the top overflow port of the vibrating screening bin 3 are respectively connected to the top of the micro-silicon powder bin 4 through the micro-silicon powder pipeline 11; the top of the silicon powder storage tank 2 and the discharge port at the bottom thereof are both connected to the nitrogen conveying pipeline; and the top of the vibrating screening bin 3 and the micro-silicon powder outlet at the bottom thereof are both connected to the nitrogen conveying pipeline. N2 is introduced through the nitrogen conveying pipeline to purge the micro-silicon powder remaining in the silicon powder storage tank 2 and the vibrating screening bin 3, and the micro-silicon powder is blown into the micro-silicon powder bin 4 through the micro-silicon powder pipeline 11. At the same time, N2 is introduced into the vibrating screening bin, and the vibration of the vibrating screening bin can discharge as much air as possible remaining in the silicon powder.

[0031] As a preferred embodiment, the micro-silicon powder bin 4 collects the micro-silicon powder screened by the vibrating screening bin, and the collected micro-silicon powder is conveyed to a trichlorosilane synthesis device for effective utilization. The top of the micro-silicon powder bin 4 is connected to the first dust collector 8, and the input pipeline and the output pipeline of the first dust collector 8 are both connected to the top of the micro-silicon powder bin 4. By connecting the first dust collector 8 to the micro-silicon powder bin 4, the micro-silicon powder entrained in N2 and the micro-silicon powder carried out during pressure relief can be sent to the first dust collector 8 through the input pipeline, and then be sent back to the micro-silicon powder bin 4 through the output pipeline after being filtered. The pressure relief process is to relieve the pressure of the micro-silicon powder bin 4 when feeding, so that the pressure is less than the pressure of the vibrating screening bin 3, so that the micro-silicon powder can smoothly enter the micro-silicon powder bin 4. During the pressure relief process, the micro-silicon powder with too small particle size is easily suspended in the bin, and the micro-silicon powder in the bin is carried out with the airflow during pressure relief. At this time, the first dust collector 8 is opened to filter the micro-silicon powder, and after the pressure relief is completed, the filtered micro-silicon powder is sent back to the micro-silicon powder bin 4 from the output pipeline of the first dust collector 8.

[0032] As a preferred embodiment, the top of the low-pressure bin 6 is connected with a second dust collector 9, and the input pipe and the output pipe of the second dust collector 9 are both connected to the top of the low-pressure bin 6. By connecting the second dust collector 9 with the low-pressure bin 6, the silicon powder brought out during the purging and pressure relief can be sent into the second dust collector 9 through the input pipe, and then sent back to the low-pressure bin 6 through the output pipe after being filtered and treated.

[0033] As a preferred embodiment, the discharge port of the low-pressure bin 6 is connected with a hot nitrogen gas conveying pipe, which can preheat the silicon powder and further dry the silicon powder and remove the air in the silicon powder.

[0034] As a preferred embodiment, the high-pressure bin 7 is connected with the cold hydrogenation reaction device, and the high-pressure bin 7 is pressurized by hydrogen gas, which is the raw material of the cold hydrogenation reaction. The raw material is sent into the high-pressure bin 7 during the pressurization, and then sent into the cold hydrogenation reaction device for reaction. The top of the high-pressure bin 7 is connected with a third dust collector 10, and the input pipe and the output pipe of the third dust collector 10 are both connected to the top of the high-pressure bin 7. By connecting the third dust collector 10 with the high-pressure bin 7, the silicon powder brought out during the purging and pressure relief can be sent into the third dust collector 10 through the input pipe, and then sent back to the high-pressure bin 7 through the output pipe after being filtered and treated, thereby improving the utilization rate of the silicon powder in the cold hydrogenation reaction device.

[0035] It should be noted that the purging and pressure relief of the low-pressure bin 6 and the high-pressure bin 7 are both required during the feeding, so that the silicon powder can smoothly enter the bin. For example, when the high-pressure bin 7 is purged to 0.2 MPa, the pressure in the high-pressure bin 7 is lower than that in the low-pressure bin 6, and the silicon powder can be sent into the high-pressure bin 7. However, the silicon powder is easily brought out during the purging and pressure relief. Therefore, the second dust collector 9 and the third dust collector 10 can filter and treat the silicon powder, and then send it back to the bin.

[0036] In some embodiments of the present application, valves are arranged at one end or both ends of the connecting pipes between the silicon powder tank car 1, the silicon powder storage tank 2, the vibrating sieve bin 3, the micro-silicon powder bin 4, the silicon powder bin 5, the low-pressure bin 6, the high-pressure bin 7, the first dust collector 8, the second dust collector 9, the third dust collector 10, and the nitrogen gas conveying pipe, for controlling the conveying of the silicon powder and the nitrogen gas, and for controlling the opening and closing of the bins, such as controlling the intermittent feeding of the high-pressure bin 7 to the cold hydrogenation reaction device.

[0037] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A silicon powder charging system, characterized by, The vibrating screening bin is provided with at least one micro-silicon powder outlet and one silicon powder outlet, and the micro-silicon powder outlet is connected with the feeding port of the micro-silicon powder bin, and the silicon powder outlet is connected with the feeding port of the silicon powder bin; the discharging port of the micro-silicon powder bin is connected with the three-chloro-silane synthesis device; the discharging port of the silicon powder bin is connected with the feeding port of the low-pressure bin; the discharging port of the low-pressure bin is connected with the feeding port of the high-pressure bin, and the silicon powder is sent into the high-pressure bin after being heated and dried; the discharging port of the high-pressure bin is connected with the cold hydrogenation reaction device, and the silicon powder is pushed into the cold hydrogenation reaction device after being pressurized.

2. The silicon dust charging system of claim 1, wherein The silicon powder tank vehicle is used for conveying the silicon powder to the silicon powder storage tank, and the discharging port of the silicon powder storage tank is connected with the top feeding port of the vibrating screening bin.

3. The silicon dust charging system of claim 2, wherein The top overflow port of the silicon powder storage tank and the top overflow port of the vibrating screening bin are respectively connected with the top of the micro-silicon powder bin through the micro-silicon powder pipeline; the top and the bottom of the silicon powder storage tank are connected with the nitrogen conveying pipeline; the top and the bottom of the vibrating screening bin are connected with the nitrogen conveying pipeline.

4. A silicon dust feeding system according to any one of claims 1 to 3, characterized in that The top of the micro-silicon powder bin is connected with the first dust collector, and the input pipeline and the output pipeline of the first dust collector are connected with the top of the micro-silicon powder bin.

5. The silicon dust charging system of claim 1, wherein The top of the low-pressure bin is connected with the second dust collector, and the input pipeline and the output pipeline of the second dust collector are connected with the top of the low-pressure bin.

6. The silicon dust charging system of claim 1, wherein The top of the high-pressure bin is connected with the third dust collector, and the input pipeline and the output pipeline of the third dust collector are connected with the top of the high-pressure bin.

7. The silicon dust charging system of claim 1, wherein The discharging port of the low-pressure bin is connected with the hot nitrogen conveying pipeline.

8. The silicon dust charging system of claim 1, wherein The vibrating screening bin is provided with a high-frequency vibrating device and a vibrating screen, the high-frequency vibrating device is used for vibrating the vibrating screen, and the vibrating screen is detachably connected in the vibrating screening bin.

9. The silicon dust charging system of claim 1, wherein The micro-silicon powder outlet of the vibrating screening bin is located at the bottom of the vibrating screening bin, and the silicon powder outlet of the vibrating screening bin is obliquely arranged on the inclined side wall of the vibrating screening bin close to the bottom.

Images