Polycrystalline silicon slurry concentration tower and polycrystalline silicon slurry treatment system comprising same

Abstract

The utility model relates to a polycrystalline silicon slurry concentrating tower and a polycrystalline silicon slurry treatment system comprising the concentrating tower. A spraying opening is formed in the side face of the upper end of the concentration tower, the inner side of the spraying opening is connected with a spraying pipe, the spraying pipe is installed at the upper end of the interior of the concentration tower, the spraying opening is sequentially connected with a third cooler and a rectifying tower, and after mixed liquid in the rectifying tower is cooled, gas-phase chlorosilane is washed to remove impurities. Compared with the prior art, the low-temperature chlorosilane liquid is used for washing away metal impurities and boron and phosphorus impurities carried out by the gas, and the obtained chlorosilane finished product is high in purity, few in impurities and better in quality.

Description

Technical Field

[0001] The utility model relates to the technical field of polysilicon production, and more specifically, to a polysilicon slurry concentration tower and a polysilicon slurry treatment system including the concentration tower. Background Art

[0002] During the production process of the polysilicon cold hydrogenation process, a large amount of slurry is generated. The slurry is mainly separated into solid and liquid through filtration. The liquid phase is the slurry recovery liquid, which mainly includes chlorosilane and high-boiling substances, and needs to be treated in a concentration tower to recover chlorosilane and reduce waste emissions.

[0003] The chlorosilane obtained through the treatment of the existing concentration tower still contains impurities such as metals and boron phosphorus, and the purity of chlorosilane needs to be improved. Summary of the Invention

[0004] The technical problem to be solved by the utility model is that the chlorosilane obtained through the treatment of the existing concentration tower still contains impurities such as metals and boron phosphorus, and the purity of chlorosilane needs to be improved.

[0005] To solve the above technical problem, according to one aspect of the utility model, a polysilicon slurry concentration tower is provided. Among them, a spray port is provided on the upper side surface of the concentration tower. The inner side of the spray port is connected to a spray pipe, and the spray pipe is installed at the upper end inside the concentration tower. The spray port is sequentially connected to a three-stage cooler and a rectification tower, and the mixed liquid of the rectification tower is cooled to wash the gaseous chlorosilane to remove impurities.

[0006] Preferably, the spray pipe includes a long pipe and two short pipes. The long pipe and the two short pipes form a trident structure. The long pipe is between the two short pipes, and the long pipe is arranged parallel to the two short pipes. The long pipe coincides with the inner diameter of the upper end of the concentration tower.

[0007] Preferably, the length of the long pipe is 1.3 m, and the lengths of the two short pipes are both 1.1 m.

[0008] Preferably, an opening is provided every 10 cm on the spray pipe.

[0009] Preferably, the diameter of the opening is 15 mm.

[0010] Preferably, the opening faces downward and the angle with the horizontal direction is 45 degrees.

[0011] Preferably, the concentration tower is a plate rectification tower, including a tower body and a plurality of sieve plates installed inside the tower body.

[0012] Preferably, the number of sieve plates is 15 layers.

[0013] Preferably, the diameter of the concentration tower is 1.4 m.

[0014] According to another aspect of the present utility model, there is provided a polysilicon slurry treatment system, which includes the above-mentioned concentration tower, and further includes a primary cooler, a secondary cooler, a refined product tank, a tertiary cooler, a hydrolysis tank, a reboiler, a rectification tower, a non-condensable gas treatment unit, and a neutralized water to wastewater treatment unit.

[0015] A feed inlet is provided on the side of the middle part of the concentration tower for feeding the slurry recovery liquid.

[0016] A gas phase outlet is provided at the top of the concentration tower for discharging gaseous chlorosilane. The gas phase outlet is sequentially connected to the primary cooler and the refined product tank, or sequentially connected to the primary cooler, the secondary cooler, and the refined product tank. The gaseous chlorosilane is cooled to obtain a chlorosilane finished product, and the unliquefied gas after cooling is connected to the non-condensable gas treatment unit for waste gas treatment.

[0017] A reboiler inlet and a reboiler outlet are respectively provided on the side of the lower end of the concentration tower for connecting the reboiler.

[0018] A bottom solid material outlet is provided at the bottom of the concentration tower for separating the solid waste residue at the bottom of the concentration tower. The bottom solid material outlet is connected to the hydrolysis tank, and the wastewater formed by the hydrolysis reaction of the bottom solid material with lime water is connected to the neutralized water to wastewater treatment unit.

[0019] Compared with the prior art, the technical solution provided by the embodiment of the present utility model can at least achieve the following beneficial effects:

[0020] First, metal impurities and boron and phosphorus impurities carried out by the gas are washed down by the low-temperature chlorosilane liquid, and the obtained chlorosilane finished product has high purity, few impurities, and better quality.

[0021] Second, the spray pipe has a three-way structure, with a larger spray range and better impurity removal effect.

[0022] Third, one outlet of the rectification tower 9 is sequentially connected to the tertiary cooler and the spray port, and the chlorosilane mixed liquid is recycled, which not only saves materials, but also refines the chlorosilane finished product, with less waste materials, higher efficiency, and higher production safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present utility model and do not limit the present utility model.

[0024] Figure 1 It is a schematic structural diagram of a polysilicon slurry concentration tower provided by this embodiment;

[0025] Figure 2 This is the process flow diagram of polysilicon slurry treatment in this embodiment. Specific embodiments

[0026] To make the objectives, technical solutions and advantages of the embodiments of the present utility model clearer, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are some but not all of the embodiments of the present utility model. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present utility model without creative efforts shall fall within the scope of protection of the present utility model.

[0027] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present utility model belongs. The terms "first", "second" and similar terms used in the specification and claims of the patent application of the present utility model do not denote any order, quantity or importance, but are only used to distinguish different components. Similarly, the terms such as "a" or "one" do not denote a quantity limitation, but mean that there is at least one.

[0028] This embodiment provides a polysilicon slurry treatment system. The polysilicon slurry treatment system mainly processes the slurry recovered from cold hydrogenation after removing solid waste to form a slurry recovery liquid. The main component is silicon tetrachloride, containing a small amount of trichlorosilane. The polysilicon slurry treatment system includes a concentration tower 2, a primary cooler 3, a secondary cooler 3, a refined product tank 5, a tertiary cooler 6, a hydrolysis tank 7, a reboiler 8, a rectification tower 9, a non-condensable gas treatment unit and a neutralized water to wastewater treatment unit. The connection and process of each device in the polysilicon slurry treatment system are shown in Figure 2 .

[0029] The concentration tower 2 is used to separate the chlorosilane in the slurry recovery liquid from impurities such as metals and boron phosphorus. See Figure 1 , the concentration tower 2 is a plate rectification tower, including a tower body and a plurality of sieve plates installed inside the tower body. Preferably, the main structure of the tower body is a straight cylinder, the diameter of the straight cylinder is 1.4 meters, and the sieve plates are 15 layers.

[0030] A feed port 21 is provided on the side of the middle part of the concentration tower 2 for feeding the slurry recovery liquid.

[0031] The top of the concentration tower 2 is provided with a gas phase outlet 22 for discharging gaseous chlorosilane. The gas phase outlet 22 is sequentially connected to the primary cooler 3, the secondary cooler 4 and the refined product tank 5, and the gaseous chlorosilane is cooled to obtain the finished chlorosilane product after secondary cooling; the gas that is not liquefied after the secondary cooling 4 is connected to a non-condensable gas treatment unit for waste gas treatment to prevent pollution or danger. The primary cooler 3 can also be directly connected to the refined product tank 5, and the gaseous chlorosilane is cooled to obtain the finished chlorosilane product after primary cooling.

[0032] A spray port 23 is provided on the upper side of the upper end of the concentration tower 2. The inner side of the spray port 23 is connected to a spray pipe, and the spray pipe is installed at the upper end inside the concentration tower 2; an outlet of the rectification tower 9 is sequentially connected to the third cooler 6 and the spray port 23, and the mixed liquid of the rectification tower 9 is used to wash and remove impurities such as metals and boron and phosphorus from the gaseous chlorosilane discharged from the rectification after cooling. Preferably, the third cooler is a circulating water cooler with a heat exchange area of 30 m 2 and the pipeline diameter led out from the rectification tower 9 is 40 mm.

[0033] Among them, the spray pipe preferably includes a long pipe and two short pipes. The long pipe and the two short pipes form a three-way structure. The long pipe is between the two short pipes, and the long pipe is arranged parallel to the two short pipes. The long pipe coincides with the inner diameter of the upper end of the concentration tower 2. In order to contact the gaseous chlorosilane in the largest range, the length of the long pipe is 1.3 m, the lengths of the two short pipes are both 1.1 m, and at the same time, an opening is arranged every 10 cm on the spray pipe. The opening faces downward and the included angle with the horizontal direction is 45 degrees, and the diameter of the opening is 15 mm.

[0034] On the lower side of the lower end of the concentration tower 2, a reboiler inlet 24 and a reboiler outlet 25 are respectively opened for connecting the reboiler 8.

[0035] The bottom of the concentration tower 2 is provided with a bottom solid material outlet 25 for separating the solid waste residue at the bottom of the rectification. The bottom solid material outlet 25 is connected to the hydrolysis tank 7, and the bottom solid material undergoes a hydrolysis reaction with lime water, and the formed waste water is connected to the neutralized water and sent to the waste water treatment unit.

[0036] Between the pipelines connected to each device of the polysilicon slurry treatment system, there are also various regulating valves, and pumps are also set according to actual needs. Other references are to the prior art.

[0037] The working principle of the slurry treatment process of the polysilicon slurry treatment system is as follows: the cooled chlorosilane fully converges with the rising gaseous silane gas in the tower. The low-temperature chlorosilane liquid will wash down the metal impurities and boron and phosphorus impurities carried out by the gas, and then be discharged out of the tower through the bottom solid material outlet 25 for hydrolysis treatment, so as to achieve the purpose of impurity removal.

[0038] Compared with the prior art, metal impurities and boron and phosphorus impurities are washed away by using low-temperature chlorosilane liquid to carry out the gas, and the obtained chlorosilane finished product has high purity, few impurities and better quality.

[0039] The above description is only an exemplary embodiment of the present invention, rather than being used to limit the protection scope of the present invention. The protection scope of the present invention is determined by the appended claims.

Claims

1. A polysilicon slurry concentration tower, characterized in that, The upper side of the concentration tower is provided with a spray nozzle. The inner side of the spray nozzle is connected to a spray pipe. The spray pipe is installed at the upper end inside the concentration tower. The spray nozzle is sequentially connected to a tertiary cooler and a rectification tower. The mixed liquid in the rectification tower is cooled to wash the gaseous chlorosilane to remove impurities.

2. The concentrator column according to claim 1, wherein The spray pipe includes a long pipe and two short pipes. The long pipe and the two short pipes form a three-way structure. The long pipe is between the two short pipes. The long pipe is arranged parallel to the two short pipes. The long pipe coincides with the inner diameter of the upper end of the concentration tower.

3. The concentrating tower according to claim 2, wherein The length of the long pipe is 1.3 m, and the lengths of the two short pipes are both 1.1 m.

4. The concentrator column according to claim 1, characterized in that, One opening is provided every 10 cm on the spray pipe.

5. The concentrating tower according to claim 4, characterized in that, The diameter of the opening is 15 mm.

6. The concentration tower according to claim 4, characterized in that, The opening faces downward and the included angle with the horizontal direction is 45 degrees.

7. The concentrating tower according to claim 1, wherein The concentration tower is a plate rectification tower, which includes a tower body and a plurality of sieve plates installed inside the tower body.

8. The concentrator column according to claim 7, characterized in that, The number of the sieve plates is 15 layers.

9. The concentrating tower according to claim 7, characterized in that, The diameter of the concentration tower is 1.4 m.

10. A polysilicon slurry treatment system, characterized in that, It includes the concentration tower according to any one of claims 1 to 9, and also includes a primary cooler, a secondary cooler, a finished product tank, a tertiary cooler, a hydrolysis tank, a reboiler, a rectification tower, a non-condensable gas treatment unit and a neutralized water to wastewater treatment unit. A feed inlet is provided on the middle side of the concentration tower for feeding the slurry recovery liquid. A gas phase outlet is provided at the top of the concentration tower for discharging gaseous chlorosilane. The gas phase outlet is sequentially connected to the primary cooler and the finished product tank, or sequentially connected to the primary cooler, the secondary cooler and the finished product tank. The gaseous chlorosilane is cooled to obtain a chlorosilane finished product. The unliquefied gas after cooling is connected to the non-condensable gas treatment unit for waste gas treatment. A reboiler inlet and a reboiler outlet are respectively opened on the lower side of the concentration tower for connecting the reboiler. A bottom solid material outlet is provided at the bottom of the concentration tower for separating the bottom solid waste residue of the concentration tower. The bottom solid material outlet is connected to the hydrolysis tank. The wastewater formed by the hydrolysis reaction of the bottom solid material with lime water is connected to the neutralized water to wastewater treatment unit.

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