Silicon-based material preparation equipment and chlorosilane recovery system thereof

Abstract

The utility model relates to silicon-based material preparation equipment and a chlorosilane recovery system thereof. The silicon-based material preparation equipment is characterized in that a concentrating tower is provided with an inlet for feeding materials; an inlet of the reboiler is connected to a bottom outlet of the concentration tower; and the concentration tower kettle pump is additionally arranged at the bottom of the first reboiler and is used for directly conveying silicon powder-containing chlorosilane and high-boiling residues to the high-boiling cracking device through a piping. According to the utility model, the consumption of quick lime is reduced by reducing abnormal material loss caused by hydrolysis, so that the effect of saving cost is achieved; in addition, when the high-boiling cracking device is abnormal, part of chlorosilane containing silicon powder and high-boiling residues can be conveyed to the hydrolysis device; optimized configuration of resources is achieved, the material flow is controlled more finely, and the overall operation efficiency and stability are further improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of polysilicon preparation field, especially the technical field of silicon-based material preparation equipment and its chlorosilane recovery system. BACKGROUND

[0002] At present, in the production process of polysilicon or related silicon-based materials, there is a hydrogenation reaction process in the general process; cold hydrogenation reaction is a chemical reaction carried out at a relatively low temperature, mainly used for converting silicon-containing compounds such as silicon tetrachloride (SiCl4) into more valuable chlorosilanes such as trichlorosilane (SiHCl3). The reaction is usually carried out in a fluidized bed reactor, and hydrogen and catalyst are added to promote the reaction.

[0003] However, in the existing cold hydrogenation reaction equipment, the material is generally separated by a concentration tower, so that the generated product is sent to a decontamination tower for treatment, and then the chlorosilane containing silicon powder and high-boiling substances are directly sent to direct hydrolysis; but this treatment method can easily lead to low chlorosilane recovery efficiency, serious waste, high chlorine salt content in wastewater, and acidity; in addition, the consumption of raw materials such as lime is large, resulting in high cost. UTILITY MODEL CONTENT

[0004] The technical problem to be solved by the utility model is to solve the technical problems of low chlorosilane recovery efficiency, serious waste, high chlorine salt content in wastewater, and large consumption of lime in the prior art.

[0005] To solve the above technical problems, according to the utility model, a recovery system for recovering chlorosilane is provided, which comprises:

[0006] A concentration tower is provided with an inlet for feeding materials;

[0007] A first reboiler is connected to the bottom outlet of the concentration tower;

[0008] A concentration tower kettle pump is additionally provided at the bottom of the first reboiler, which is used to directly send chlorosilane containing silicon powder and high-boiling substances to a high-boiling cracking device through a pipe.

[0009] Further, the first reboiler is provided with a first outlet and a second outlet; the first outlet is communicated to the bottom of the concentration tower.

[0010] Further, the hydrolysis device is connected to the bottom of the concentration tower.

[0011] Further, the inlet of the concentration tower is connected to the outlet of the second reboiler, and the inlet of the second reboiler is connected to an inlet pipe.

[0012] Further, a second throttle valve is arranged between the inlets of all the inlet pipes and the second reboiler.

[0013] Further, a material balance system is arranged on one side of the concentration tower, and the material balance system comprises a cooling system, a concentration tower reflux tank and an exhaust port.

[0014] Further, the material balance system further comprises a back material pipeline and a conveying pipeline, the back material pipeline and the conveying pipeline are both connected to the concentration tower reflux tank at the feeding end, the back material pipeline is connected to the concentration tower at the discharging end, and the conveying pipeline is connected to the impurity removal tower at the discharging end.

[0015] The silicon-based material preparation device comprises the recovery system for recovering chlorosilane.

[0016] Compared with the prior art, the technical scheme provided by the embodiment of the utility model has at least the following beneficial effects:

[0017] Firstly, the concentration tower kettle pump is additionally arranged in the utility model, and the chlorosilane containing silicon powder and the high-boiling substance are directly sent to the high-boiling cracking device, so that the recovery efficiency of the chlorosilane is effectively improved, and waste is reduced.

[0018] Secondly, the recovery efficiency of the chlorosilane is improved by the high-boiling cracking device, the amount of material directly hydrolyzed is reduced, the content of the chloride salt in the waste water is reduced, the acidity of the waste water is reduced, and the environment is protected; in addition, the use of the hydrolysis device is reduced, and the loss of lime is reduced.

[0019] Thirdly, part of the chlorosilane containing silicon powder and the high-boiling substance are sent to the hydrolysis device under the abnormal condition of the high-boiling cracking device, and part of the chlorosilane containing silicon powder and the high-boiling substance are diverted to the hydrolysis device, so that the resource is optimally allocated, the material flow is more finely controlled, and the overall operation efficiency and stability are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the drawings of the embodiments will be briefly introduced below, and obviously, the drawings in the following description only relate to some embodiments of the utility model, and are not limited to the utility model.

[0021] Figure 1 The drawings of the utility model are shown in the drawings.

[0022] In the drawings:

[0023] Concentration column: 1

[0024] De-gassing column: 2

[0025] First reboiler: 3

[0026] First outlet: 31

[0027] Second outlet: 32

[0028] Concentration column kettle pump: 4

[0029] Pipe: 5

[0030] High-boiling cracking device: 61

[0031] Hydrolyzer: 62

[0032] Second reboiler: 8

[0033] Inlet pipe: 9

[0034] Material balance system: 10

[0035] Pump: 101

[0036] Storage tank: 102

[0037] Cooler: 103

[0038] Throttling valve (for material balance system): 104, 105

[0039] First throttling valve: 71

[0040] Second throttling valve: 72 DETAILED DESCRIPTION

[0041] To make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort fall within the scope of the present application.

[0042] Unless otherwise defined, the technical terms or scientific terms used herein should be understood as the usual meanings understood by those of ordinary skill in the art to which the present application belongs. The "first", "second" and similar words used in the patent application description and claims of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. Similarly, "one" or "a" and similar words do not represent a quantity limitation, but represent the existence of at least one.

[0043] Reference Figure 1 The embodiment provides a recovery system for recovering chlorosilane, comprising:

[0044] A concentration tower 1 is provided with an inlet for feeding materials;

[0045] A first reboiler 3 is connected to the bottom outlet of the concentration tower 1;

[0046] A concentration tower kettle pump 4 is additionally arranged at the bottom of the first reboiler 3, and is used for directly sending chlorosilane containing silicon powder and high-boiling substances to a high-boiling cracking device 61 through a pipe 5.

[0047] The series connection of the concentration tower 1 and the first reboiler 3 realizes the recovery of high-boiling substances and chlorosilane in the materials. In addition, the concentration tower kettle pump 4 is used to directly send chlorosilane containing silicon powder and high-boiling substances to the high-boiling cracking device 61, and further cracking treatment is performed, so that the discharge of waste is reduced, and the environmental protection benefit is improved. In addition, the high-boiling cracking device 61 is used to crack chlorosilane containing silicon powder and high-boiling substances, so that these components can be further recovered and utilized, and the overall utilization rate of resources is improved.

[0048] In a preferred embodiment, the first reboiler 3 is provided with a first outlet 31 and a second outlet 32; the first outlet 31 is connected to the bottom of the concentration tower 1. Such a design is usually used to achieve specific process goals, such as optimizing heat transfer, improving evaporation efficiency, or better controlling the flow of materials during concentration.

[0049] Specifically, the heated materials are directly sent into the bottom of the concentration tower 1 through the first outlet 31 of the first reboiler 3, which helps to utilize the heat energy of the hot materials to further heat and evaporate the liquid in the concentration tower, thereby improving the overall evaporation efficiency and concentration effect. At the same time, such a design also helps to reduce energy consumption, because the heat energy provided by the reboiler is more fully utilized.

[0050] In a preferred embodiment, the hydrolysis device 62 is connected to the bottom of the concentration tower 1. Connecting the hydrolysis device 62 to the bottom of the concentration tower 1 can utilize the high-temperature and high-pressure environment at the bottom of the concentration tower 1 to provide more favorable conditions for the hydrolysis reaction; at the same time, the energy consumption is reduced, and the high temperature at the bottom of the concentration tower 1 is effectively utilized.

[0051] In a preferred embodiment, the inlet of the concentration tower 1 is connected to the outlet of the second reboiler 8, and the inlet of the second reboiler 8 is connected to the inlet pipe 9; for example, Figure 1As shown, preferably there can be three inlet pipes 9, each connected to the gas outlet of the previous process. Such a design is to achieve the multi-path material feeding, and to introduce the material from different sources for unified processing. The three inlet pipes 9 are used to introduce the tail gas, so as to recover the chlorosilane material in the tail gas. The generation of the tail gas is mainly due to the reaction of silicon tetrachloride and hydrogen at high temperature in the cold hydrogenation process, in addition to the generation of chlorosilane, some by-products and tail gas are also generated. By introducing the tail gas into the second reboiler 8, the uniform mixing and heating of the multi-path tail gas can be achieved. This helps to ensure that the tail gas reaches the appropriate temperature and concentration before entering the concentration column 1, thereby improving the efficiency and stability of the concentration process in the concentration column 1.

[0052] In a preferred embodiment, a first throttle valve 71 is provided between the hydrolyzer 62 and the concentration column 1, and a gas analyzer is provided in the hydrolyzer 62. By adjusting the opening of the first throttle valve 71, the amount of material entering the concentration column 1 can be accurately controlled, thereby ensuring the stability and efficiency of the concentration process, and allowing the operator to flexibly adjust the material flow according to actual needs. In addition, the gas analyzer provided in the hydrolyzer 62 plays a role in monitoring and controlling the gas composition in the hydrolysis process. The gas analyzer can detect the gas composition in the hydrolyzer 62 in real time, including the concentration of key components such as chlorosilane. This allows the operator to timely understand the progress and effect of the hydrolysis process, so as to make adjustments as needed. For example, if the concentration of chlorosilane is detected to be too high or too low, the operator can adjust the opening of the first throttle valve 71 to ensure efficient hydrolysis.

[0053] In a preferred embodiment, a second throttle valve 72 is provided between the junction of all inlet pipes 9 and the second reboiler 8. The second throttle valve 72 is mainly used to accurately regulate the flow of material into the second reboiler 8. By adjusting the opening of the second throttle valve 72, the operator can flexibly control the total amount of material in the second reboiler 8, thereby ensuring that the heating effect in the second reboiler 8 and the subsequent concentration process can reach the best state.

[0054] In a preferred embodiment, a material balancing system 10 is provided on one side of the concentration column 1. The material balancing system 10 can adjust the excess material in the concentration column 1 by providing a pump 101, a pipeline and a concentration column reflux tank 102. For example, Figure 1As shown, the pump 101 in the balance system 10 can suck the concentrated reflux tank 102 to a vacuum state, and then the throttle valve 104 is opened, so that the concentrated reflux tank 102 sucks the material in the upper part of the concentration tower 1 into the storage tank concentrated reflux tank 102 for temporary storage. Specifically, since the top material of the concentration tower 1 is a gas phase, which is generally chlorosilane gas, dichlorodihydrogen silicon and non-condensable gas; after the above-mentioned material is cooled by the cooler 103, it becomes low-temperature chlorosilane liquid, and dichlorodihydrogen silicon and non-condensable gas which is still gas; then, the dichlorodihydrogen silicon and non-condensable gas is discharged as tail gas, and the chlorosilane liquid flows to the concentrated reflux tank 102 through the return pipe; at this time, when the throttle valve 105 is opened, the pump 101 can inject the material in the concentrated reflux tank 102 into the concentration tower 1 again, and the remaining chlorosilane liquid is transported to the impurity removal tower 2 through the conveying pipe.

[0055] In a preferred embodiment, the controller is connected with a temperature sensor arranged in the hydrolysis device 62; the controller can control the opening degree of the first throttle valve 71 according to the real-time temperature of the hydrolysis reaction, that is, the slower the reaction rate, the smaller the opening degree of the first throttle valve 71, and the faster the reaction rate, the larger the opening degree of the first throttle valve 71. The specific relationship between the opening degree and the reaction rate needs to be obtained by the tester according to the actual detection, which is not described here.

[0056] In a preferred embodiment, the high-boiling cracking device 61 is connected with a power meter connected to the controller. The connection of the high-boiling cracking device 61 with the power meter means that the power meter can monitor the power output or consumption of the high-boiling cracking device 61 in real time. When the power output of the high-boiling cracking device 61 is monitored to be abnormal, the controller can reduce the power output to the high-boiling cracking device 61 by closing or reducing the power of the concentration tower bottom pump 4.

[0057] A recovery system for recovering chlorosilane can be integrated in a silicon-based material preparation device to reduce the environmental impact; specifically, the silicon-based material preparation device is a polysilicon preparation device; the reason for recovering chlorosilane is that chlorosilane, as an important raw material or intermediate product, will be discharged with tail gas, waste liquid, etc. The recovery system captures chlorosilane in these tail gas or waste liquid, converts it into reusable resources through a series of processing steps, thereby not only reducing the environmental impact of waste, but also reducing production costs,

[0058] The above only describes exemplary embodiments of the present application, and is not intended to limit the protection scope of the present application, which is defined by the appended claims.

Claims

1. A recovery system for recovering chlorosilanes, characterized by, include: A concentration tower, wherein the concentration tower is provided with an inlet for feeding material; A first reboiler, the inlet of which is connected to the bottom outlet of the concentration tower; A reboiler pump for the concentration tower is added at the bottom of the first reboiler and is used to directly send chlorosilane containing silicon powder and high-boiling substances to the high-boiling cracking unit through piping.

2. The recovery system for recovering chlorosilanes according to claim 1, wherein The first reboiler is provided with a first outlet and a second outlet; the first outlet is connected to the bottom of the concentration tower, and the hydrolyzer is connected to the bottom of the concentration tower.

3. The recovery system for recovering chlorosilanes according to claim 2, wherein The hydrolyzer is connected to the bottom of the concentration tower.

4. The recovery system for recovering chlorosilanes according to claim 2, wherein The inlet of the concentration tower is connected to the outlet of the second reboiler, and the inlet of the second reboiler is connected to an inlet pipe.

5. The recovery system for recovering chlorosilanes according to claim 4, wherein A first throttling valve is provided between the hydrolyzer and the concentration tower.

6. The recovery system for recovering chlorosilanes according to claim 5, wherein A second throttle valve is provided between the inlet of the inlet pipe and the second reboiler.

7. The recovery system for recovering chlorosilanes according to claim 1, wherein A material balance system is provided on one side of the concentration tower. The material balance system includes a cooling system, a concentration tower reflux tank, and an exhaust port. One end of the cooling system is connected to the concentration tower, and the other end of the cooling system is connected to the concentration tower reflux tank and the exhaust port, respectively.

8. The recovery system for recovering chlorosilanes according to claim 7, wherein The material balance system also includes a return pipeline and a conveying pipeline; the inlet of both the return pipeline and the conveying pipeline is connected to the reflux tank of the concentration tower, the outlet of the return pipeline is connected to the concentration tower, and the outlet of the conveying pipeline is connected to the impurity removal tower.

9. The recovery system for recovering chlorosilanes according to claim 8, wherein The high-boiling-point pyrolysis unit is connected to a power meter, and the power meter and the bottom pump of the concentration tower are connected to a controller.

10. A silicon-based material preparation apparatus, comprising a recovery system for recovering chlorosilanes as described in any one of claims 1 to 8.

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