Experimental system for chlorosilane rectification separation

Abstract

The invention relates to an experimental system for chlorosilane rectification separation, and belongs to the technical field of rectification separation. The system comprises a rectifying tower feeding mechanism, a rectifying separation mechanism, a material extraction mechanism and an auxiliary operation mechanism which are communicated in sequence. The feeding mechanism comprises a raw material storage tank, a filter, a feeding pump and a preheater; the rectification separation mechanism comprises a rectification tower, a rectification tower kettle, a tower kettle heater, a tower top condenser and a reflux ratio controller; the material extraction mechanism comprises a tower top product tank, a tower kettle cooler and a tower kettle extraction tank; the device solves the technical problems that a traditional industrial rectification device is high in equipment investment, large in energy consumption, poor in operation flexibility and long in process optimization period, the equipment investment and operation cost can be reduced, efficient separation of trichlorosilane and silicon tetrachloride can be achieved, the production efficiency is improved, and the production cost is reduced. And metal impurities such as boron and phosphorus can be effectively removed.

Description

Technical Field

[0001] This invention relates to the field of distillation and separation technology, and more specifically, to an experimental system for the distillation and separation of chlorosilanes. Background Technology

[0002] Trichlorosilane (SiHCl3) is a key intermediate in the synthesis of high-purity polycrystalline silicon, monocrystalline silicon, and other silicon-based materials. Its purity directly affects the product performance and yield in downstream industries such as photovoltaics and semiconductors. Industrially, trichlorosilane is mainly prepared by the hydrogenation reaction of industrial silicon powder, hydrogen chloride, and silicon tetrachloride (SiCl4). However, industrial silicon powder often contains metallic impurities such as boron, phosphorus, and iron. These impurities form corresponding metal chlorides during the reaction and enter the trichlorosilane system, seriously affecting the electrical and optical properties of the final silicon material. To meet the demand of the photovoltaic and semiconductor industries for high-purity trichlorosilane (such as solar-grade purity ≥6N and electronic-grade purity ≥9N), the crude product must be efficiently separated and purified.

[0003] Currently, distillation is the most commonly used separation method in industry. Its principle is based on the differences in boiling points between trichlorosilane, silicon tetrachloride, and various metal chlorides. Through multi-tower coupling and continuous distillation, component separation and impurity removal are achieved. However, traditional industrial distillation systems face the following technical problems during the distillation process:

[0004] Traditional industrial distillation equipment is typically large-scale, with towers tens of meters high, and uses steam heating and circulating water cooling. While it can achieve efficient separation, it suffers from high equipment investment, high energy consumption, poor operational flexibility, and long process optimization cycles. Industrial equipment is particularly unsuitable for research and development scenarios such as new process development, catalyst evaluation, and small-batch high-purity sample preparation, and its operating costs are extremely high. Furthermore, existing laboratory distillation equipment is mostly designed for common organic solvents, exhibiting significant shortcomings in corrosion resistance, sealing, operating pressure and temperature range, and process adaptability to the characteristics of chlorosilanes. Therefore, developing a chlorosilane distillation and separation experimental system suitable for laboratory environments, capable of simulating industrial distillation processes, and possessing high separation efficiency, good operational flexibility, and safety is of great significance for promoting the research and development of trichlorosilane purification processes, reducing experimental costs, and accelerating the industrialization of new materials and processes. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an experimental system for the distillation and separation of chlorosilanes that can simulate the industrial distillation process under small-scale conditions, effectively reduce equipment investment and operating costs, achieve efficient separation of trichlorosilane and silicon tetrachloride, effectively remove metallic impurities such as boron and phosphorus, and effectively prevent oxygen and water vapor from entering the system, thus avoiding the hydrolytic corrosion of the equipment by chlorosilanes.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An experimental system for the distillation and separation of chlorosilanes includes a distillation column feed mechanism, a distillation separation mechanism, a material collection mechanism, and an auxiliary operating mechanism arranged sequentially. The distillation column feed mechanism includes a raw material storage tank, a filter, a feed pump, and a preheater. The distillation separation mechanism includes a distillation column, a distillation column reboiler, a reboiler heater, a top condenser, and a reflux ratio controller. The material collection mechanism includes a top product tank, a reboiler cooler, and a reboiler collection tank. The auxiliary operating mechanism includes a nitrogen supply device and a circulating cooler.

[0008] The present invention is further configured such that: the raw material storage tank is connected to the feed pump via a filter; the feed pump is connected to the preheater; the preheater is connected to the distillation column; a column bottom heater is provided outside the column bottom of the distillation column; the column top condenser is connected to the reflux ratio controller; the reflux ratio controller is connected to both the distillation column and the column top product tank; and the column bottom cooler is connected to both the column bottom of the distillation column and the column bottom outlet tank.

[0009] The present invention is further configured such that: the nitrogen supply equipment is connected to the raw material storage tank, the top product tank, the bottom product tank, and the bottom of the distillation column, respectively; and the circulating cooler provides cooling medium to the top condenser and the bottom cooler, respectively.

[0010] The present invention is further configured such that: the bottom of the distillation column is a packed column, and the packing inside the bottom of the distillation column is Dixon packing with a packing size of 2-3mm × 2-3mm.

[0011] The present invention is further configured such that: the inner diameter of the distillation column bottom is 50 mm, the height is 1.4-1.5 m, and the bottom capacity is 4-10 L.

[0012] The present invention is further configured such that the reflux ratio control range of the reflux ratio controller is 1:100 to 100:1.

[0013] The present invention is further configured such that: the temperature range of the tower bottom heater is 0-500℃, and the cooling temperature range of the circulating cooler is -20-10℃.

[0014] The present invention is further configured such that: the raw material storage tank is connected to a feed inlet, and the distillation column includes multiple distillation column sections that are interconnected.

[0015] The advantages of this invention are: 1. By adopting a modular design, this invention has a small overall size and a small footprint, making it particularly suitable for laboratory environments. It can simulate industrial distillation processes under small-scale conditions, effectively reducing equipment investment and operating costs.

[0016] 1. In the process of using this invention, the system uses Dixon packing which has the characteristics of large specific surface area, low pressure drop and high mass transfer efficiency. Combined with wide range of reflux ratio control, it can achieve efficient separation of trichlorosilane and silicon tetrachloride, and can effectively remove metal impurities such as boron and phosphorus. The purity of the product can reach the requirements of solar energy grade or semiconductor grade.

[0017] 2. During the use of this invention, the system is equipped with a nitrogen supply device to fully purge and inertate the device, effectively preventing oxygen and water vapor from entering the system and avoiding hydrolytic corrosion of the device by chlorosilane. Attached Figure Description

[0018] Figure 1 This is a flowchart illustrating the use of a chlorosilane distillation and separation experimental system according to the present invention.

[0019] In the diagram: 1. Raw material storage tank; 2. Filter; 3. Feed pump; 4. Preheater; 5. Distillation column bottom; 6. Distillation column; 7. Top condenser; 8. Reflux ratio controller; 9. Top product tank; 10. Bottom cooler; 11. Bottom outlet tank; 12. Nitrogen supply equipment; 13. Circulating cooler; 14. Bottom heater. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0021] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0022] In this invention, unless otherwise stated, the directional terms such as "up" and "down" generally refer to the directions shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" generally refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0023] Please see Figure 1This invention provides the following technical solution: specifically, it refers to an experimental system for the distillation and separation of chlorosilanes, comprising a distillation column feeding mechanism, a distillation separation mechanism, a material discharging mechanism, and an auxiliary operating mechanism arranged sequentially; the distillation column feeding mechanism includes a raw material storage tank 1, a filter 2, a feed pump 3, and a preheater 4; the distillation separation mechanism includes a distillation column 6, a distillation column reboiler 5, a reboiler heater 14, a top condenser 7, and a reflux ratio controller 8; the material discharging mechanism includes a top product tank 9, a reboiler cooler 10, and a reboiler discharging tank 11; the auxiliary operating mechanism includes a nitrogen supply device 12 and a circulating cooler 13; the raw material storage... Storage tank 1 is connected to feed pump 3 via filter 2. Feed pump 3 is connected to preheater 4. Preheater 4 is connected to distillation column 6. Distillation column bottom 5 is equipped with bottom heater 14. Top condenser 7 is connected to reflux ratio controller 8. Reflux ratio controller 8 is connected to distillation column 6 and top product tank 9 respectively. Bottom cooler 10 is connected to distillation column bottom 5 and bottom outlet tank 11 respectively. Nitrogen supply equipment 12 is connected to raw material storage tank 1, top product tank 9, bottom outlet tank 11 and distillation column bottom 5 respectively. Circulating cooler 13 provides cooling medium to top condenser 7 and bottom cooler 10 respectively.

[0024] Furthermore, the distillation column reboiler 5 is a packed column, and the packing inside the distillation column reboiler 5 is Dixon packing (Dixon packing has a high specific surface area and excellent mass transfer performance. Combined with a wide range of reflux ratio control, it can achieve efficient separation of trichlorosilane and silicon tetrachloride. The removal rate of metal impurities such as boron and phosphorus in the product can reach more than 90%, and the purity of trichlorosilane can reach the requirements of solar energy grade (≥6N) or semiconductor grade (≥9N)). The packing size is 2-3mm × 2-3mm; the inner diameter of the distillation column reboiler 5 is 50mm, the height is 1.4-1.5m, and the reboiler capacity is 4-10L; the reflux ratio controller 8 has a reflux ratio control range of 1:100 to 100:1; the reboiler heater temperature range is 0-500℃, and the circulating cooler cooling temperature range is -20-10℃; the raw material storage tank 1 is connected to a feed inlet, and the distillation column 6 includes multiple distillation column sections 401 that are interconnected.

[0025] A specific application of this embodiment is as follows: Before conducting specific experimental operations, the interconnections between various mechanisms are as follows: First, the raw material storage tank 1 is connected to the inlet of the feed pump 3 through the filter 2. The outlet of the feed pump 3 is connected to the preheater 4. The outlet of the preheater 4 is connected to the feed inlet in the middle of the distillation column 6. The reboiler heater 14 installed outside the reboiler 5 of the distillation column is used to heat and vaporize the material in the reboiler. The inlet of the top condenser 7 is connected to the top outlet of the distillation column 6. The outlet of the top condenser 7 is connected to the reflux ratio controller 8. The reflux ratio controller 8 is connected to the distillation column 6. The upper reflux port is connected to the top product tank 9, the inlet of the bottom cooler 10 is connected to the bottom outlet of the distillation column bottom 5, and the outlet of the bottom cooler 10 is connected to the bottom collection tank 11. Meanwhile, the nitrogen supply equipment 12 is connected to the raw material storage tank 1, the top product tank 9, the bottom collection tank 11 and the distillation column bottom 5 through branch pipes. After the connection, each branch pipe is equipped with a pressure relief valve and the gas is collected into the pressure relief main pipe. Finally, the circulating cooler 13 is connected to the cooling medium inlet of the top condenser 7 and the bottom cooler 10 through two independent cooling medium pipelines.

[0026] In addition, during implementation, this system is primarily used for the efficient separation and purification of mixtures of trichlorosilane and silicon tetrachloride in a laboratory environment. It can also be used for research on the removal of metallic impurities (such as boron, phosphorus, and other chlorides). Before conducting distillation experiments, nitrogen supply equipment 12 is activated to purge the system into the raw material storage tank 1, the top product tank 9, the bottom product tank 11, and the distillation column bottom 5. This purging process lasts for at least 24 hours, thoroughly removing oxygen and water vapor from the system. This ensures that the oxygen content is below 10 ppm and the water vapor content is below 20 ppm. Simultaneously, during the purging process, a slight positive pressure is maintained within the entire system at 0.01-0.05 ppm. To prevent air infiltration from the external environment during the implementation process, before conducting the experiment, industrial-grade raw materials containing trichlorosilane and silicon tetrachloride (usually containing metallic impurities such as B and P) are added to the feed inlet (one or more inlets) connected to the raw material storage tank 1. This allows the industrial-grade raw materials containing trichlorosilane and silicon tetrachloride to enter the raw material storage tank 1. Once the industrial-grade raw materials containing trichlorosilane and silicon tetrachloride enter the raw material storage tank 1, the feed pump 3 is started. During this process, the industrial-grade raw materials containing trichlorosilane and silicon tetrachloride pass through filter 2. After solid impurities are removed, the feed material enters preheater 4. Once inside preheater 4, the industrial-grade feed material containing trichlorosilane and silicon tetrachloride (with solid impurities removed) is preheated to 40-60°C. This improves feed uniformity, reduces viscosity, and prevents crystallization blockage at low temperatures. Subsequently, the preheated industrial-grade feed material containing trichlorosilane and silicon tetrachloride is fed into distillation column 6, with the system pressure set to 0.1-0.3 MPa (preferably 0.3 MPa). Once the entire system has established a certain system pressure (MPa), the reboiler heater 14 is started, and the heating power is gradually increased, causing the reboiler temperature to slowly rise to the range of 60-100℃. At the same time, the top temperature is controlled at 50-90℃ by the top condenser 7. During this process, the gas-liquid balance is gradually established by adjusting the heating power and the cooling flow rate of the annular cooler 13. After the system is running stably, the reflux ratio controller 8 is started, and the system is first run in full reflux mode for 1 hour to ensure uniform gas-liquid distribution in the column. Then, the reflux ratio is adjusted to 0 according to the target product purity.Continuous or intermittent sampling is performed within the range of 7-100°C. After continuous or intermittent sampling, the relatively high-purity trichlorosilane vapor is condensed by the top condenser 7 and then enters the reflux ratio controller 8. Part of it is refluxed back into the distillation column 6 to maintain separation efficiency, while the other part is collected as high-purity trichlorosilane product and sent to the top product tank 9. The unvaporized liquid in the bottom 5 of the distillation column mainly consists of silicon tetrachloride and impurities containing boron, phosphorus, and other metal chlorides. This liquid containing silicon tetrachloride and boron, phosphorus, and other metal chlorides is subsequently cooled to a safe temperature by the bottom cooler 10 and then discharged into the bottom collection tank 11 for collection and subsequent analysis or processing. Throughout the experiment, the circulating cooler 13 provides a stable cooling medium (such as ethylene glycol aqueous solution) for the top condenser 7 and the bottom cooler 10, with the cooling temperature controlled between -20°C and 10°C to ensure condensation effect and operational safety. The nitrogen supply equipment 12 is always kept at a pressure at least 0.04 ppm higher than the distillation system pressure. The system pressure is adjusted in real time via pressure relief valves on each branch pipe to effectively prevent material backflow or leakage (pressure sensors, temperature sensors, and flow meters are installed in key parts of the entire system to achieve full-process monitoring and automated control). After extraction, the reboiler heater 14, feed pump 3, and circulating cooler 13 are turned off in sequence, and the system is allowed to cool naturally to room temperature. The remaining material is discharged into the corresponding storage tank, and the nitrogen purging system is purged again to keep the system dry and clean for subsequent experiments.

[0027] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0028] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0029] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0030] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0031] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A system for the distillation and separation of chlorosilanes, characterized in that: It includes a distillation column feeding mechanism, a distillation separation mechanism, a material dispensing mechanism, and an auxiliary operating mechanism that are connected in sequence. The distillation column feeding mechanism includes a raw material storage tank (1), a filter (2), a feed pump (3), and a preheater (4). The distillation separation mechanism includes a distillation column (6), a distillation column bottom (5), a bottom heater (14), a top condenser (7), and a reflux ratio controller (8). The material collection mechanism includes a top product tank (9), a bottom cooler (10), and a bottom collection tank (11). The auxiliary operating mechanism includes a nitrogen supply device (12) and a circulating cooler (13).

2. The experimental system for distillation and separation of chlorosilanes according to claim 1, characterized in that: The raw material storage tank (1) is connected to the feed pump (3) through the filter (2). The feed pump (3) is connected to the preheater (4). The preheater (4) is connected to the distillation column (6). The distillation column bottom (5) is equipped with a bottom heater (14). The top condenser (7) is connected to the reflux ratio controller (8). The reflux ratio controller (8) is connected to the distillation column (6) and the top product tank (9) respectively. The bottom cooler (10) is connected to the distillation column bottom (5) and the bottom collection tank (11) respectively.

3. The experimental system for distillation and separation of chlorosilanes according to claim 2, characterized in that: The nitrogen supply equipment (12) is connected to the raw material storage tank (1), the top product tank (9), the bottom product tank (11), and the bottom of the distillation column (5), respectively. The circulating cooler (13) provides cooling medium to the top condenser (7) and the bottom cooler (10), respectively.

4. The experimental system for distillation and separation of chlorosilanes according to claim 3, characterized in that: The distillation column bottom (5) is a packed column, and the packing inside the distillation column bottom (5) is Dixon packing with a size of 2-3mm × 2-3mm.

5. The experimental system for distillation and separation of chlorosilanes according to claim 4, characterized in that: The distillation column reboiler (5) has an inner diameter of 50 mm, a height of 1.4-1.5 m, and a capacity of 4-10 L.

6. The experimental system for distillation and separation of chlorosilanes according to claim 5, characterized in that: The reflux ratio control range of the reflux ratio controller (8) is 1:100 to 100:

1.

7. The experimental system for distillation and separation of chlorosilanes according to claim 6, characterized in that: The temperature range of the tower bottom heater is 0-500℃, and the cooling temperature range of the circulating cooler is -20-10℃.

8. The experimental system for distillation and separation of chlorosilanes according to claim 7, characterized in that: The raw material storage tank (1) is connected to a feed inlet, and the distillation column (6) includes multiple distillation column sections (401) that are connected to each other.

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