A polycrystalline silicon slurry concentration device

Abstract

The utility model provides a kind of polysilicon slag slurry concentration device, including the stripping column for the polysilicon slag slurry concentration, wherein, the tower kettle (7) upper side of stripping column is equipped with slag slurry inlet tower pipeline (1), the top of the tower kettle (7) is equipped with rectification section (6), the bottom of the tower kettle (7) is equipped with kettle bottom cone part (12), the bottom of the kettle bottom cone part (12) is equipped with discharge pipeline (11), the bottom side of the tower kettle (7), equipped with the first hydrogen pipeline (2) for input hydrogen, the conical surface of the kettle bottom cone part (12), equipped with second hydrogen pipeline (3), another end of the second hydrogen pipeline (3) is communicated with the first hydrogen pipeline (2).

Description

Technical Field

[0001] This utility model relates to a slurry concentration device, and more particularly to a polycrystalline silicon slurry concentration device. Background Technology

[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.

[0003] Currently, the silicon powder produced by the cold hydrogenation unit in polysilicon production has a purity of only 99%. During the reaction in a fluidized bed, when the particle diameter decreases to a certain extent, it is carried out of the fluidized bed by the gas phase. After being washed off by a Venturi scrubber, the chlorosilanes carrying silicon powder and impurities are called slurry. The slurry is discharged to a distillation tower (called a stripping tower) with a concentration effect for concentration. When the solid content of the chlorosilanes in the bottom of the tower is 5%-8%, it is then discharged to downstream units for further processing.

[0004] Currently, stripping towers used in the industry often experience bridging issues during operation. Because the bubbling hydrogen inlet coil is installed above the conical section, silicon powder tends to accumulate in the space below the coil, causing bridging. This makes it difficult for the silicon powder to exit the tower, affecting the normal operation of the stripping tower. In severe cases, it requires tower shutdown, replacement, and cleaning. This not only disrupts the normal operation of production units and causes economic losses due to production load adjustments, but also requires cleaning every 4-6 months. Furthermore, the shutdown and cleaning processes carry risks of material leakage and personnel injury.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0006] Purpose of the invention: The technical problem to be solved by this utility model is to provide a polycrystalline silicon slag slurry concentration device to address the shortcomings of the existing technology.

[0007] To address the aforementioned technical problems, this utility model discloses a polycrystalline silicon slag slurry concentration device, comprising a stripping tower for polycrystalline silicon slag slurry concentration. The stripping tower has a slag inlet pipeline on the upper side of its bottom, a rectification section at the top, a bottom cone at the bottom, a discharge pipeline at the bottom of the cone, a first hydrogen pipeline for inputting hydrogen on the side of the bottom, and a second hydrogen pipeline on the conical surface of the bottom cone, the other end of which is connected to the first hydrogen pipeline.

[0008] Furthermore, the end of the first hydrogen pipeline furthest from the reboiler is fluidly connected to the hydrogen feed pipeline via a heater, for feeding heated hydrogen into the reboiler.

[0009] Furthermore, the rectification section is equipped with a reflux condenser.

[0010] Furthermore, the condensation reflux device includes:

[0011] The condenser is fluidly connected to the top of the rectification section at its inlet end, and the condenser is fluidly connected to the inlet end of the reflux tank at its outlet end. The reflux tank is fluidly connected to the side of the rectification section via a reflux pump.

[0012] Furthermore, the second hydrogen pipeline is configured as multiple lines, evenly distributed around the conical surface of the bottom cone of the vessel.

[0013] Furthermore, the second hydrogen pipeline includes:

[0014] A main pipeline is connected at one end to the first hydrogen pipeline, and the other end of the main pipeline is fluidly connected to one end of several branch pipelines, the other end of which is connected to the interior of the tower.

[0015] Furthermore, the branch lines are evenly distributed around the conical surface of the bottom cone of the vessel.

[0016] Furthermore, a flow meter is installed on the main pipeline.

[0017] Furthermore, a thermometer is installed on the branch pipeline.

[0018] Furthermore, a regulating valve is also installed on the branch pipeline.

[0019] Beneficial effects:

[0020] 1. This utility model significantly reduces the probability of bridging caused by the accumulation of silica powder and impurity powder in the cone section of the slurry, avoiding economic losses caused by cleaning blockages; it improves the efficiency of the concentration device, reduces electricity consumption by about 10-20%, and reduces the overall production cost of the product.

[0021] 2. This invention can be used not only for hydrogenation production, but also for other powder-containing liquids that require concentration. The bubbling gas can be adjusted according to the reaction raw materials. Attached Figure Description

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0023] Figure 1 This is a schematic diagram of the overall structure of one embodiment.

[0024] Figure 2 This is a top view of the conical section of a cylindrical body according to one embodiment.

[0025] In the diagram: 1 is the slurry inlet pipeline, 2 is the first hydrogen pipeline, 3 is the second hydrogen pipeline, 4 is the heater, 5 is the hydrogen feed pipeline, 6 is the rectification section, 7 is the reboiler, 8 is the reflux pump, 9 is the reflux tank, 10 is the condenser, 11 is the discharge pipeline, 12 is the bottom cone of the reboiler; 30 is the main pipeline, 301 is the flow meter, 31 is the branch pipeline, 311 is the thermometer, and 312 is the regulating valve. Detailed Implementation

[0026] The overall design concept of this utility model is as follows:

[0027] The silicon powder accumulated in the conical part of the tower bottom is prone to bridging due to its structure. Bridging leads to blockage of the tower bottom, restricting the discharge of slurry. Stopping the tower to clean the blockage in the conical part not only consumes manpower and resources, but also causes significant economic losses due to load adjustments during the process.

[0028] This invention, based on the original stripping tower structure (refer to CN209797497U), adds a hydrogen branch to the cone section of the tower bottom, allowing bubbling from the cone section, significantly improving the concentration effect and reducing heat and hydrogen usage. While maintaining the concentration effect, the power consumption of a single unit can be reduced by 600,000 kWh; it also avoids on-site bridging, greatly reducing economic losses and operational risks caused by unclogging the stripping tower. The main flow meter displays the total hydrogen flow rate, while the branch pipeline regulating valves can accurately and efficiently adjust the hydrogen flow rate in each pipeline. Temperature point monitoring of pipeline blockage allows for timely purging, preventing branch blockage and loss of bubbling effect, and ensuring the unit's operational cycle.

[0029] like Figure 1 As shown, the technical solution of this utility model is as follows:

[0030] The polycrystalline silicon slurry concentration device includes a stripping tower. The upper side of the tower bottom 7 of the stripping tower is provided with a slurry inlet pipeline 1. The top of the tower bottom 7 is provided with a rectification section 6. The bottom of the tower bottom 7 is provided with a bottom cone 12. The bottom of the bottom cone 12 is provided with a discharge pipeline 11 for discharging the concentrated slurry.

[0031] The bottom side of the tower 7 is equipped with a first hydrogen pipeline 2 for external hydrogen input.

[0032] The other end of the first hydrogen pipeline 2 is fluidly connected to the hydrogen feed pipeline 5 via a heater 4, and is used to input heated hydrogen into the reboiler 7.

[0033] The rectification section 6 is equipped with a reflux condenser, as detailed below:

[0034] The top of the rectification section 6 is fluidly connected to the inlet of the condenser 10, the outlet of the condenser 10 is fluidly connected to the inlet of the reflux tank 9, and the outlet of the reflux tank 9 is fluidly connected to the side of the rectification section 6 through the reflux pump 8.

[0035] On the conical surface of the bottom cone 12, there is a second hydrogen pipeline 3, and the other end of the second hydrogen pipeline 3 is connected to the first hydrogen pipeline 2.

[0036] The second hydrogen pipeline 3 is configured as multiple lines, evenly distributed around the conical surface, specifically including:

[0037] One end of the main pipeline 30 is connected to the first hydrogen pipeline 2, and the other end of the main pipeline 30 is fluidly connected to one end of several branch pipelines 31; the other ends of the branch pipelines 31 are evenly distributed around the conical surface of the bottom cone 12 and are connected to the inside of the tower 7.

[0038] A total flow meter 301 is installed on the main pipeline 30 to detect the hydrogen gas in the main pipeline 30.

[0039] The branch pipeline 31 is equipped with a branch thermometer 311 and a branch regulating valve 312, which are used to detect the temperature of hydrogen in the branch pipeline 31 and regulate the hydrogen flow rate, respectively.

[0040] Example:

[0041] In one specific embodiment, three streams of hydrogen gas are added to the lower part of the cone section 13 at the bottom of the reactor, evenly distributed across a circular cross-section. This arrangement, closer to the bottom than in the original device, results in better bubbling. The cone section is less prone to silicon powder bridging due to bubbling, allowing for smoother discharge of the slurry from the bottom. The key technical point of this invention is that the bubbling gas pipeline in the slurry concentration device is split from one stream into two (the pipeline from heater 4 was originally one stream, now it's two). The newly added bubbling gas pipeline 3, after being divided into three sub-pipelines, is evenly inserted into the reactor from the lower part of the cone section, near the circular cross-section. The gas exiting the pipeline bubbles the liquid in the reactor. The hydrogen gas exiting heater 4 bubbles the material in the reactor, raising the gas temperature above the maximum boiling point of chlorosilane under current operating conditions, thus improving vaporization efficiency and preventing powdery substances in the slurry from bridging in the cone section.

[0042] like Figure 2 As shown, a flow meter 301 is installed on the newly added hydrogen refueling pipeline main 30 to monitor the hydrogen flow rate and to observe whether the branch lines are blocked. The main pipeline 30 is divided into three branch pipelines 31, each equipped with a regulating valve 312 and a thermometer 311. The regulating valve flexibly adjusts the amount of hydrogen used in each branch line, and the thermometer monitors the pipeline blockage. If the pipeline is blocked, the temperature will be significantly lower than that of the other pipelines.

[0043] When this utility model is in operation:

[0044] 1. The slurry discharged from the upstream process to this concentration unit enters the stripping tower from the upper part of the cylinder 7 through the slurry inlet pipeline 1. Hydrogen gas heated by heater 4 is introduced into the tower bottom through pipelines 2 and 3 to bubble the material, increase the gas-liquid contact and change the partial pressure of chlorosilane, so that the chlorosilane vaporizes and rises to the rectification section 6. Here, it exchanges heat with the lower temperature liquid chlorosilane from the reflux tank 9 for rectification and purification. The silicon powder and impurities at the bottom 7 of the tower bottom are difficult to vaporize due to their higher boiling point and accumulate and boil in the cone. Then, they are discharged to the downstream of the unit for treatment through the slag discharge pipeline 11.

[0045] 2. A portion of the pure chlorosilane obtained in reflux tank 9 is sent downstream for recovery, while the other portion is refluxed into the stripping tower for distillation.

[0046] The use of this invention results in higher bubbling efficiency of hydrogen in the bottom slurry, improving the slurry concentration effect. While maintaining the same concentration effect, the total hydrogen flow rate used in this unit can be reduced by approximately 18%, and the hydrogen temperature at the heater outlet can be reduced by 21%, thus reducing the electricity consumption of the heater. Calculations show that in a 30,000-ton-per-year cold hydrogenation unit, this invention saves approximately 600,000 kWh of electricity annually, reducing production costs.

[0047] This utility model provides a concept and method for a polycrystalline silicon slag slurry concentration device. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. All components not explicitly stated in this embodiment can be implemented using existing technology.

Claims

1. A polysilicon slag slurry concentration device, comprising a stripping tower for concentrating polysilicon slag slurry, wherein, The top side of the stripping tower bottom (7) is provided with a slurry inlet pipeline (1), the top of the bottom (7) is provided with a rectification section (6), the bottom of the bottom (7) is provided with a bottom cone (12), the bottom of the bottom cone (12) is provided with a discharge pipeline (11), and the bottom side of the bottom of the bottom (7) is provided with a first hydrogen pipeline (2) for inputting hydrogen. The characteristic is that a second hydrogen pipeline (3) is provided on the cone surface of the bottom cone (12), and the other end of the second hydrogen pipeline (3) is connected to the first hydrogen pipeline (2).

2. The polycrystalline silicon slag slurry thickening device according to claim 1, characterized in that, The end of the first hydrogen pipeline (2) away from the bottom of the tower (7) is fluidly connected to the hydrogen feed pipeline (5) through a heater (4) for feeding heated hydrogen into the bottom of the tower (7).

3. The polycrystalline silicon slag slurry thickening device according to claim 2, characterized in that, The rectification section (6) is equipped with a condensation reflux device.

4. A polycrystalline silicon slag slurry thickening device according to claim 3, characterized in that, The condensation reflux device includes: The inlet end of the condenser (10) is fluidly connected to the top of the rectification section (6), the outlet end of the condenser (10) is fluidly connected to the inlet end of the reflux tank (9), and the outlet end of the reflux tank (9) is fluidly connected to the side of the rectification section (6) via the reflux pump (8).

5. A polycrystalline silicon slag slurry thickening device according to claim 4, characterized in that, The second hydrogen pipeline (3) is configured as multiple lines, which are evenly distributed around the conical surface of the bottom cone (12).

6. A polycrystalline silicon slag slurry thickening device according to claim 5, characterized in that, The second hydrogen pipeline (3) includes: A main pipeline (30) is connected at one end to the first hydrogen pipeline (2), and the other end of the main pipeline (30) is fluidly connected to one end of several branch pipelines (31), and the other end of the branch pipelines (31) is connected to the inside of the tower (7).

7. A polycrystalline silicon slag slurry thickening device according to claim 6, characterized in that, The branch lines (31) are evenly distributed around the conical surface of the bottom cone (12).

8. A polycrystalline silicon slag slurry thickening device according to claim 7, characterized in that, A flow meter (301) is installed on the main pipeline (30).

9. A polycrystalline silicon slag slurry thickening device according to claim 8, characterized in that, A thermometer (311) is installed on the branch pipeline (31).

10. A polycrystalline silicon slag slurry thickening device according to claim 9, characterized in that, The branch pipeline (31) is also equipped with a regulating valve (312).

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