CN115259165A - Trichlorosilane purification process in polycrystalline silicon production process - Google Patents
Trichlorosilane purification process in polycrystalline silicon production process Download PDFInfo
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Abstract
The invention belongs to the technical field of industrial production of polycrystalline silicon, and provides a process for purifying trichlorosilane in a polycrystalline silicon production process. The process comprises the following steps: light component removal: introducing liquid-phase crude chlorosilane from a cold hydrogenation section into a light component removal tower to obtain liquid-phase crude trichlorosilane; complexing and adsorbing: introducing the liquid-phase crude trichlorosilane into a complexing adsorption device, and performing complexing adsorption on part of metal impurities and B, P nonmetal impurities; rough distillation: introducing the liquid-phase crude trichlorosilane obtained after the complex adsorption into a crude distillation unit, removing metal impurities, B, P non-metal impurities and high-low boiling point substances, and obtaining primary purified trichlorosilane liquid; CPS adsorption: introducing the primarily purified silicon trichloride solution into a CPS adsorption device to further remove impurities; and (3) rectification: and introducing the liquid phase trichlorosilane after the CPS adsorption into a rectification unit to obtain high-purity trichlorosilane liquid. The invention optimally combines the complexation adsorption, CPS adsorption and rectification processes, can effectively reduce B, P and other impurities in trichlorosilane, and reduces the rectification cost.
Description
Technical Field
The invention belongs to the technical field of industrial production of polycrystalline silicon, and particularly relates to a trichlorosilane purification process in a polycrystalline silicon production process.
Background
In the production process of the polycrystalline silicon, because industrial silicon powder, hydrogen chloride, hydrogen, externally purchased trichlorosilane and the like carry metal impurities and non-metal impurities, and impurities are brought in when materials flow through an equipment pipeline, the types and the contents of the impurities in the initial raw material chlorosilane are more, and B, P, C, O and elements such as metals (Fe, cr, ni, cu, zn, na, al and the like) are mainly used.
Trichlorosilane is used as a raw material for producing polycrystalline silicon, and a multi-stage strict impurity removal process is carried out before the trichlorosilane enters a reduction furnace to react with hydrogen to prepare the polycrystalline silicon. Most of the impurity content meets the production requirement after single rectification and purification, but part of boron and phosphorus impurity compounds in the trichlorosilane have boiling points close to that of the trichlorosilane and are difficult to remove by directly adopting a rectification method, so that the content of the impurities is still higher than the final requirement and needs to be further removed.
At present, the purification purpose is basically achieved through multi-stage rectification at home and abroad, but the rectification and purification energy consumption is high, the investment is large, and great pressure is caused to the operation and production of enterprises. In addition, in recent years, in domestic enterprises remove impurities through adsorption devices and remove boron and phosphorus impurities by utilizing a chemical adsorption principle, but a series of chemical reactions can occur in the adsorption process, the reactions are almost irreversible, the adsorbent needs to be frequently replaced, the adsorption efficiency is greatly reduced in the later period of use, and the content of B, P in the adsorbed chlorosilane cannot meet the requirement.
The complex adsorption not only has stronger adsorption capacity, but also has reversible selective adsorption process, and the adsorbate can realize desorption separation under certain conditions. The selective adsorption of the complex bond is utilized in the complex adsorption, so that the disadvantages of weak van der Waals force bond energy, irreversible adsorption of other chemical reactions and the like are overcome, and the method is an adsorption separation technology with application and research prospects.
The complex adsorption is combined with other adsorption modes and is combined with the optimization of the rectification process, so that the trichlorosilane in the production of the polycrystalline silicon can be purified more efficiently and economically.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a trichlorosilane Purification process in the polysilicon production process, which effectively reduces the content of impurities such as B, P in trichlorosilane and the like and simultaneously reduces the operation cost of a rectification System by optimally combining complex adsorption, CPS (Chlorosilane Purification System) adsorption and the rectification process.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
a trichlorosilane purification process in a polycrystalline silicon production process comprises the following operation steps:
step S1: removing light; introducing liquid-phase crude chlorosilane from a cold hydrogenation section into a light component removal tower, and removing light components to obtain liquid-phase crude trichlorosilane;
step S2: complexing and adsorbing; introducing the liquid-phase crude trichlorosilane into a complexing adsorption device, and performing complexing adsorption treatment on part of metal impurities and B, P non-metal impurities by the complexing adsorption device;
and step S3: carrying out rough distillation; introducing the liquid-phase crude trichlorosilane obtained after the complex adsorption into a crude distillation unit, removing metal impurities, B, P non-metal impurities and high-low boiling point substances, and obtaining primary purified trichlorosilane liquid;
and step S4: CPS adsorption; introducing the primarily purified silicon trichloride solution into a CPS adsorption device, and further removing impurities in the primarily purified silicon trichloride solution;
step S5: rectification; and introducing the liquid phase trichlorosilane after the CPS adsorption into a rectification unit to obtain high-purity trichlorosilane liquid.
Further, the liquid-phase crude chlorosilane in the step S1 is a liquid-phase mixture of dichlorosilane, trichlorosilane, and hydrogen chloride containing metallic impurities and non-metallic impurities, wherein the metallic impurities include Fe, cr, ni, cu, zn, na, al, and K, and the non-metallic impurities include B, P.
Further, in the step S1, the light component removed by the light component removal tower is dichlorosilane; the working temperature of the lightness-removing tower is 60-95 ℃, and the working pressure is 0.2-0.6Mpag.
Further, the complex adsorption device in step S2 includes two parallel complex adsorption towers, which are respectively: a complexing adsorption tower A and a complexing adsorption tower B; the complexing adsorption columns are all provided with a vertical bed structure, and complexing adsorbents are loaded on the complexing adsorption columns; the complexing adsorbent is silica gel loaded medicament.
Further, the volume of the complexing adsorption tower is 7.5m 3 The periphery of the complexing adsorption tower is provided with a regeneration heating jacket, and the working temperature of the complexing adsorption tower is between 30 and 90 ℃.
Further, the rough distillation unit in the step S3 comprises at least three rough distillation devices connected in series; the crude distillation device is a packed tower.
Furthermore, the crude distillation unit comprises a first crude distillation tower, a second crude distillation tower and a third crude distillation tower which are sequentially connected in series, wherein the working temperature of the first crude distillation tower is 60-70 ℃, and the working pressure is 0.1-0.3Mpag; the working temperature of the second coarse distillation tower is 80-90 ℃, and the working pressure is 0.35-0.40Mpag; the working temperature of the third crude distillation tower is 90-110 ℃, and the working pressure is 0.4-0.7Mpag.
Further, the working temperature of the CPS adsorption device in the step S4 is 84-93 ℃, and the working pressure is 0.3-0.5Mpag.
Furthermore, the rectification unit in the step S5 at least comprises three stages of rectification devices connected in series; and the rectifying devices are all packed towers.
Furthermore, the rectification unit comprises a first rectification tower, a second rectification tower and a third rectification tower which are sequentially connected in series, wherein the working temperature of the first rectification tower is 55-70 ℃, and the working pressure is 0.1-0.3Mpag; the working temperature of the second rectifying tower is 80-100 ℃, and the working pressure is 0.3-0.5Mpag; the working temperature of the third rectifying tower is 100-115 ℃, and the working pressure is 0.6-0.8Mpag.
Compared with the prior art, the invention has the following beneficial effects:
(1) The trichlorosilane purification process in the polysilicon production process provided by the invention comprehensively considers the factors such as the impurity condition (impurity content and variety) of a polysilicon system, the cost and effect of a purification device, comprehensive energy consumption and the like, scientifically and reasonably arranges the adsorption device and the sequence of rough distillation and rectification, firstly removes light components such as dichlorosilane and the like by using a light component removal tower, then forms a complex compound by using a complex adsorption device for part of metal impurities and nonmetal impurities such as B, P and the like in liquid-phase rough trichlorosilane to adsorb, then carries out rough distillation treatment by a rough distillation unit and adsorption treatment by a CPS adsorption device, and finally carries out rectification and purification by a rectification unit; compared with the prior art, the method adopts a process combining various adsorption modes with rectification optimization, scientifically arranges the positions and the sequence of the impurity removal devices, can efficiently remove part of metal impurities, B, P and other non-metal impurities in trichlorosilane in the production of polycrystalline silicon, keeps the contents of the metal impurities and B, P at ppb level, and has high purification precision and efficiency;
(2) According to the trichlorosilane purification process in the polycrystalline silicon production process, multiple adsorption and rectification combined processes are adopted, after multiple adsorption devices are added before rectification, impurities needing to be rectified and removed in trichlorosilane are relatively reduced, the reflux ratio of a rectification device is reduced, the energy consumption is remarkably reduced, equipment installation is relatively simple, the investment is small, the purpose of reducing the operation cost of enterprises can be achieved, and cost reduction, quality improvement and efficiency improvement are achieved.
Drawings
FIG. 1 is a schematic structural diagram of a process flow of trichlorosilane purification according to an embodiment of the present invention;
the notation in the figure is: 1-light component removal tower; 2-complex adsorption device, 21-complex adsorption tower A, 22-complex adsorption tower B; 3-a crude distillation unit; 4-CPS adsorption unit; 5-a rectification unit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
Referring to fig. 1, an embodiment of the present invention provides a trichlorosilane purification process in a polysilicon production process, where the process includes the following operation steps:
step S1: removing light; introducing liquid-phase crude chlorosilane from a cold hydrogenation section into a light component removal tower 1, and removing light components to obtain liquid-phase crude trichlorosilane;
step S2: complexing and adsorbing; introducing the liquid-phase crude trichlorosilane into a complexing adsorption device 2, and performing complexing adsorption treatment on part of metal impurities and B, P nonmetal impurities by the complexing adsorption device 2;
and step S3: carrying out rough distillation; introducing the liquid-phase crude trichlorosilane obtained after the complex adsorption into a crude distillation unit 3, removing metal impurities, B, P non-metal impurities and high-low boiling point substances, and obtaining primary purified trichlorosilane liquid;
and step S4: CPS adsorption; introducing the primarily purified trichlorosilane liquid into a CPS adsorption device 4, and further removing impurities in the primarily purified trichlorosilane liquid;
step S5: rectifying; and (3) introducing the liquid phase trichlorosilane after the CPS adsorption into a rectification unit 5 to obtain high-purity trichlorosilane liquid.
Specifically, in the step S1, the liquid-phase crude chlorosilane is a liquid-phase mixture of dichlorosilane, trichlorosilane, and hydrogen chloride, which contains metallic impurities such as Fe, cr, ni, cu, zn, na, al, and K, and non-metallic impurities such as B, P; the light component removing tower 1 is a sieve plate tower, and the light component removed by the light component removing tower is light components such as dichlorosilane; the working temperature of the lightness-removing tower is 60-95 ℃, and the working pressure is 0.2-0.6Mpag.
The complexing adsorption device 2 in the step S2 comprises two complexing adsorption towers which are connected in parallel and respectively comprise: a complexing adsorption tower A21 and a complexing adsorption tower B22; the complexing adsorption columns are all provided with a vertical bed structure, and complexing adsorbents are loaded on the complexing adsorption columns; the collateralsThe synthetic adsorbent is a silica gel loaded medicament which comprises silica-alumina gel inorganic minerals (aluminum gel framework composite Lewis acid-base mixture) and can effectively adsorb and remove part of metal impurities and non-metal impurities such as B, P in the liquid-phase crude trichlorosilane discharged from the light-ends removal tower 1 in a more targeted manner. The volume of the complexing adsorption tower is 7.5m 3 The periphery of the complexing adsorption tower is provided with a regeneration heating jacket for heating, and the working temperature of the complexing adsorption tower is between 30 and 90 ℃.
The rough distillation unit 3 in the step S3 comprises three rough distillation devices which are connected in series, namely a first rough distillation tower, a second rough distillation tower and a third rough distillation tower which are connected in series in sequence, wherein the rough distillation devices are all packed towers; wherein the working temperature of the first crude distillation tower is 60-70 ℃, and the working pressure is 0.1-0.3Mpag; the working temperature of the second coarse distillation tower is 80-90 ℃, and the working pressure is 0.3-0.4Mpag; the working temperature of the third crude distillation tower is 90-110 ℃, and the working pressure is 0.4-0.7Mpag.
The CPS adsorption device in the step S4 is used for performing CPS adsorption treatment on the trichlorosilane liquid discharged by the rough distillation unit 3, the CPS adsorption device is formed by connecting two adsorption columns in parallel, and an adsorbent is filled in the adsorption columns and is based on the principle that a solid adsorbent is subjected to adsorption separation based on the chemical bond polarity of a compound; the working temperature is 84-93 ℃, and the working pressure is 0.3-0.5Mpag.
The rectifying unit 5 in the step S5 comprises three stages of rectifying devices connected in series, which are a first rectifying tower, a second rectifying tower and a third rectifying tower respectively; the rectifying devices are all packed towers; wherein the working temperature of the first rectifying tower is 55-70 ℃, and the working pressure is 0.1-0.3Mpag; the working temperature of the second rectifying tower is 80-100 ℃, and the working pressure is 0.3-0.5Mpag; the working temperature of the third rectifying tower is 100-115 ℃, and the working pressure is 0.6-0.8Mpag.
The advantageous effects of the present invention will be further described below with reference to examples and comparative examples.
Example 1
The composition of the liquid-phase crude chlorosilane is 97.44 percent of trichlorosilane and 2.49 percent of dichlorosilane, the impurity B is less than or equal to 45ppbw, the impurity P is less than or equal to 2ppbw, and the total amount of metal impurities is less than or equal to 1000ng/g.
Step S1: removing light; introducing liquid-phase crude chlorosilane into a lightness removing tower 1 for lightness removing treatment to obtain a crude trichlorosilane liquid product, wherein the tower kettle temperature is 83 ℃ and the tower kettle pressure is 0.38Mpag in the lightness removing process, and the feeding amount is controlled not to exceed 5m per hour 3 ；
Step S2: complexing and adsorbing; introducing the crude trichlorosilane liquid into a complexing adsorption device 2 for complexing adsorption treatment, wherein the temperature of the complexing reaction is 60 ℃;
and step S3: carrying out rough distillation; introducing the product obtained in the step S2 into a first crude distillation tower, a second crude distillation tower and a third crude distillation tower which are sequentially connected in series for crude distillation, wherein the tower kettle working temperature of the first crude distillation tower is 60 ℃, and the tower kettle pressure is 0.165Mpag; the tower kettle temperature of the second crude distillation tower is 81 ℃, and the tower kettle pressure is 0.35Mpag; the tower kettle working temperature of the third crude distillation tower is 91 ℃, and the tower kettle pressure is 0.45Mpag;
and step S4: CPS adsorption; introducing the product obtained in the step S3 into a CPS adsorption device 4, wherein the top temperature is 91.1 ℃, the top pressure is 0.30Mpag, the bottom temperature is 84.5 ℃, and the bottom pressure is 0.37Mpag;
step S5: rectification; introducing the product obtained in the step S4 into a first rectifying tower, a second rectifying tower and a third rectifying tower which are sequentially connected in series for rectifying, wherein the tower kettle temperature of the first rectifying tower is 58 ℃, and the tower kettle pressure is 0.14Mpag; the temperature of the tower bottom of the second rectifying tower is 83 ℃, and the pressure of the tower bottom is 0.37Mpag; the temperature of the third rectifying tower bottom is 107.7 ℃, and the pressure of the third rectifying tower bottom is 0.64Mpag.
The purity of the trichlorosilane finally obtained by the steps is more than 6N, the impurity B is less than or equal to 0.3ppbw, the impurity P is less than or equal to 1.0ppbw, and the total content of the impurities (except Ca) is 2+ )≤10ng/g。
Comparative example 1
The liquid-phase crude chlorosilane comprises 97.44 percent of trichlorosilane and 2.49 percent of dichlorosilane, wherein the impurity B is less than or equal to 45ppbw, the impurity P is less than or equal to 2ppbw, and the total amount of metal impurities is less than or equal to 1000ng/g.
Step S1: removing light; introducing liquid-phase crude chlorosilane into a lightness-removing tower 1 for lightness-removing treatment to obtain a crude trichlorosilane liquid product, wherein the tower kettle temperature in the lightness-removing processThe temperature is 83 ℃, the pressure of the tower bottom is 0.38Mpag, and the feeding amount is controlled not to exceed 5m per hour 3 ；
Step S2: complexing and adsorbing; introducing crude trichlorosilane liquid into a complex adsorption device 2 for complex adsorption treatment, wherein the temperature of complex reaction is 60 ℃;
and step S3: carrying out rough distillation; introducing the product obtained in the step S2 into a first crude distillation tower, a second crude distillation tower and a third crude distillation tower which are sequentially connected in series for crude distillation, wherein the tower kettle working temperature of the first crude distillation tower is 60 ℃, and the tower kettle pressure is 0.165Mpag; the temperature of the tower kettle of the second crude distillation tower is 81 ℃, and the pressure of the tower kettle is 0.35Mpag; the tower kettle working temperature of the third crude distillation tower is 91 ℃, and the tower kettle pressure is 0.45Mpag;
and step S4: rectifying; introducing the product obtained in the step S4 into a first rectifying tower, a second rectifying tower and a third rectifying tower which are sequentially connected in series for rectifying, wherein the tower kettle temperature of the first rectifying tower is 58 ℃, and the tower kettle pressure is 0.14Mpag; the temperature of the tower kettle of the second rectifying tower is 83 ℃, and the pressure of the tower kettle is 0.37Mpag; the temperature of the tower bottom of the third rectifying tower is 107.7 ℃, and the pressure of the tower bottom is 0.64Mpag.
The purity of the trichlorosilane finally obtained through the steps is more than 5N, the impurity B is less than or equal to 0.8ppbw, the impurity P is less than or equal to 1.5ppbw, and the total impurity content (except Ca) is total 2+ )≤50ng/g。
Example 2
The liquid-phase crude chlorosilane comprises 99.90 percent of trichlorosilane and 0.73 percent of dichlorosilane by weight, wherein the impurity B is less than or equal to 7ppbw, the impurity P is less than or equal to 2ppbw, and the total amount of metal impurities is less than or equal to 100ng/g.
Step S1: removing light; introducing liquid-phase crude chlorosilane into a lightness-removing tower 1 for lightness-removing treatment to obtain a crude trichlorosilane liquid product, wherein the tower kettle temperature is 84.5 ℃, the tower kettle pressure is 0.385Mpag in the lightness-removing process, and the feeding amount is controlled not to exceed 5m per hour 3 ；
Step S2: complexing and adsorbing; introducing crude trichlorosilane liquid into a complex adsorption device 2 for complex adsorption treatment, wherein the temperature of complex reaction is 60 ℃;
and step S3: carrying out rough distillation; introducing the product obtained in the step S2 into a first crude distillation tower, a second crude distillation tower and a third crude distillation tower which are sequentially connected in series for crude distillation, wherein the working temperature of a tower kettle of the first crude distillation tower is 61 ℃, and the pressure of the tower kettle is 0.170Mpag; the tower kettle temperature of the second crude distillation tower is 81.3 ℃, and the tower kettle pressure is 0.35Mpag; the tower bottom working temperature of the third crude distillation tower is 92 ℃, and the tower bottom pressure is 0.455Mpag;
and step S4: CPS adsorption; introducing the product obtained in the step S3 into a CPS adsorption device 4, wherein the top temperature is 91.6 ℃, the top pressure is 0.30Mpag, the bottom temperature is 85.1 ℃, and the bottom pressure is 0.37Mpag;
step S5: rectification; introducing the product obtained in the step S4 into a first rectifying tower, a second rectifying tower and a third rectifying tower which are sequentially connected in series for rectifying, wherein the tower kettle temperature of the first rectifying tower is 58.4 ℃, and the tower kettle pressure is 0.145Mpag; the temperature of the tower bottom of the second rectifying tower is 83.2 ℃, and the pressure of the tower bottom is 0.375Mpag; the temperature of the tower bottom of the third rectifying tower is 108.7 ℃, and the pressure of the tower bottom is 0.646Mpag.
The purity of the trichlorosilane finally obtained through the steps is more than 8N, the impurity B is less than or equal to 0.1ppbw, the impurity P is less than or equal to 0.06ppbw, and the total impurity content is (except Ca) 2+ )≤8ng/g。
Comparative example 2
The liquid-phase crude chlorosilane comprises 99.90 percent of trichlorosilane and 0.73 percent of dichlorosilane by weight, wherein the impurity B is less than or equal to 7ppbw, the impurity P is less than or equal to 2ppbw, and the total amount of metal impurities is less than or equal to 100ng/g.
Step S1: removing light; introducing liquid-phase crude chlorosilane into a lightness-removing tower 1 for lightness-removing treatment to obtain a crude trichlorosilane liquid product, wherein the tower kettle temperature is 84.5 ℃, the tower kettle pressure is 0.385Mpag in the lightness-removing process, and the feeding amount is controlled to be not more than 5m per hour 3 ；
Step S2: carrying out rough distillation; introducing the product obtained in the step S2 into a first crude distillation tower, a second crude distillation tower and a third crude distillation tower which are sequentially connected in series for crude distillation, wherein the working temperature of a tower kettle of the first crude distillation tower is 61 ℃, and the pressure of the tower kettle is 0.170Mpag; the tower kettle temperature of the second crude distillation tower is 81.3 ℃, and the tower kettle pressure is 0.35Mpag; the working temperature of the tower bottom of the third crude distillation tower is 92 ℃, and the pressure of the tower bottom is 0.455Mpag;
and step S3: CPS adsorption; introducing the product obtained in the step S3 into a CPS adsorption device 4, wherein the top temperature is 91.6 ℃, the top pressure is 0.30Mpag, the bottom temperature is 85.1 ℃, and the bottom pressure is 0.37Mpag;
and step S4: rectification; introducing the product obtained in the step S4 into a first rectifying tower, a second rectifying tower and a third rectifying tower which are sequentially connected in series for rectifying, wherein the tower kettle temperature of the first rectifying tower is 58.4 ℃, and the tower kettle pressure is 0.145Mpag; the temperature of the tower bottom of the second rectifying tower is 83.2 ℃, and the pressure of the tower bottom is 0.375Mpag; the temperature of the tower bottom of the third rectifying tower is 108.7 ℃, and the pressure of the tower bottom is 0.646Mpag.
The purity of the trichlorosilane finally obtained by the steps is more than 6N, the impurity B is less than or equal to 0.7ppbw, the impurity P is less than or equal to 1.4ppbw, and the total content of the impurities (except Ca) is 2+ )≤30ng/g。
The above description is only an example of the present application and is not intended to limit the present invention. Any modification, equivalent replacement, and improvement made within the scope of the application of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A trichlorosilane purification process in a polycrystalline silicon production process is characterized by comprising the following operation steps:
step S1: removing light; introducing liquid-phase crude chlorosilane from a cold hydrogenation section into a light component removal tower (1), and removing light components to obtain liquid-phase crude trichlorosilane;
step S2: complexing and adsorbing; introducing the liquid-phase crude trichlorosilane into a complexing adsorption device (2), and performing complexing adsorption treatment on part of metal impurities and B, P nonmetal impurities by the complexing adsorption device (2);
and step S3: carrying out rough distillation; introducing the liquid-phase crude trichlorosilane obtained after the complex adsorption into a crude distillation unit (3), removing metal impurities, B, P non-metal impurities and high-low boiling point substances, and obtaining primarily purified trichlorosilane liquid;
and step S4: CPS adsorption; introducing the primarily purified silicon trichloride solution into a CPS adsorption device (4) to further remove impurities in the primarily purified silicon trichloride solution;
step S5: rectifying; and (4) introducing the liquid phase trichlorosilane after CPS adsorption into a rectification unit (5) to obtain high-purity trichlorosilane liquid.
2. The trichlorosilane purification process in the polysilicon production process according to claim 1, wherein the liquid-phase crude chlorosilane in the step S1 is a liquid-phase mixture of dichlorosilane, trichlorosilane, and hydrogen chloride containing metallic impurities and non-metallic impurities, the metallic impurities include Fe, cr, ni, cu, zn, na, al, and K, and the non-metallic impurities include B, P.
3. The trichlorosilane purification process in the polysilicon production process according to claim 1, wherein in the step S1, the lightness-removing tower (1) is a sieve plate tower, and light components removed by the lightness-removing tower comprise dichlorosilane; the working temperature of the lightness-removing tower is 60-95 ℃, and the working pressure is 0.2-0.6Mpag.
4. The trichlorosilane purification process in the polysilicon production process according to claim 1, wherein the complex adsorption device (2) in the step S2 comprises two parallel complex adsorption towers, which are respectively: a complex adsorption tower A (21) and a complex adsorption tower B (22); the complexing adsorption columns are all provided with a vertical bed structure, and complexing adsorbents are loaded on the complexing adsorption columns; the complexing adsorbent is silica gel loaded medicament.
5. The trichlorosilane purification process in the polysilicon production process according to claim 4, wherein the volume of the complexing adsorption tower is 7.5m 3 The periphery of the complexing adsorption tower is provided with a regeneration heating jacket, and the working temperature of the complexing adsorption tower is between 30 and 90 ℃.
6. The trichlorosilane purification process in the polysilicon production process according to claim 1, wherein the rough distillation unit (3) in the step S3 comprises at least three rough distillation devices connected in series; the crude distillation device is a packed tower.
7. The trichlorosilane purification process in the polysilicon production process according to claim 6, wherein the rough distillation unit (3) comprises a first rough distillation tower, a second rough distillation tower and a third rough distillation tower which are sequentially connected in series, the working temperature of the first rough distillation tower is 60-70 ℃, and the working pressure is 0.1-0.3Mpag; the working temperature of the second crude distillation tower is 80-90 ℃, and the working pressure is 0.3-0.4Mpag; the working temperature of the third crude distillation tower is 90-110 ℃, and the working pressure is 0.4-0.7Mpag.
8. The trichlorosilane purification process in the polysilicon production process according to claim 1, wherein the CPS adsorption device in the step S4 has a working temperature of 84-93 ℃ and a working pressure of 0.3-0.5Mpag.
9. The trichlorosilane purification process in the polysilicon production process according to claim 1, wherein the rectification unit (5) in the step S5 at least comprises three stages of rectification devices connected in series; the rectifying devices are all packed towers.
10. The trichlorosilane purification process in the polysilicon production process according to claim 9, wherein the rectification unit (5) comprises a first rectification tower, a second rectification tower and a third rectification tower which are sequentially connected in series, the working temperature of the first rectification tower is 55-70 ℃, and the working pressure of the first rectification tower is 0.1-0.3Mpag; the working temperature of the second rectifying tower is 80-100 ℃, and the working pressure is 0.3-0.5Mpag; the working temperature of the third rectifying tower is 100-115 ℃, and the working pressure is 0.6-0.8Mpag.
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| CN116407861A (en) * | 2023-03-16 | 2023-07-11 | 清电光伏科技有限公司 | Fixed bed-based electronic grade polysilicon rectification carbon removal device and method |
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