System for reducing energy loss in chlorosilane carbon removal process

Abstract

The utility model provides a system for reducing energy loss in a chlorosilane carbon removal process. The system comprises a coarse rectification unit, an extractive rectification unit, a back-extractive rectification unit, a chlorosilane recovery unit and a carbonaceous organic matter collection unit, the extractive distillation unit comprises an extraction tank and a first distillation tower, an inlet of the extraction tank is connected with an outlet of the coarse distillation unit, and an outlet is connected with an inlet of the first distillation tower; the back-extraction rectification unit comprises a buffer stirring tank and a second rectification tower, an inlet of the buffer stirring tank is connected with a tower bottom outlet of the first rectification tower, and an outlet is connected with an inlet of the second rectification tower; wherein a tower top outlet of the first rectifying tower is sequentially connected with a first cooler, a first reflux tank and a chlorosilane recycling unit, and a tower top outlet of the second rectifying tower is sequentially connected with a second cooler, a second reflux tank and a carbonaceous organic matter collecting unit, so that chlorosilane and an extracting agent are separated out for recycling, and carbonaceous components are collected for take-out. And the energy loss and the cost in the chlorosilane carbon removal process are reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to polycrystal silicon production technical field especially relates to a system of reducing energy loss in chlorosilane carbon removal process. BACKGROUND

[0002] With the rapid increase of the development of photovoltaic industry and electronic information industry, the trace impurity elements contained in polycrystal silicon have a significant influence on the electrical properties and mechanical properties of silicon material, especially the carbon-containing impurities, which have a significant influence on the photoelectric conversion efficiency of silicon material or the electrical characteristics of electronic components.

[0003] Carbon, as an important impurity, is mainly derived from carbon-containing organic matter in polycrystal silicon raw material trichlorosilane, such as methyldichlorosilane, methyltrichlorosilane, and trimethylchlorosilane. In order to ensure product quality, the generated carbon-containing products need to be removed in the production process of polycrystal silicon. The existing removal method is to use primary or secondary rectification for purification, and then to hydrolyze the chlorosilane with high carbon content after rectification and purification. However, when hydrolyzing the chlorosilane with high carbon content, a large amount of silicon and chlorine elements are lost, thereby increasing the production cost, and the carbon-containing organic matter is not recycled, causing resource waste.

[0004] Therefore, the present application provides a system for reducing energy loss in chlorosilane carbon removal process to solve the above problems. UTILITY MODEL CONTENTS

[0005] One of the purposes of the present application is to provide a system for reducing energy loss in chlorosilane carbon removal process to solve the problem that in the existing chlorosilane carbon removal process, after rectification and purification, the chlorosilane with high carbon content is hydrolyzed, which causes a large amount of silicon and chlorine elements to be lost, increases the production cost, and the carbon-containing organic matter is not recycled, causing resource waste.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] A system for reducing energy loss in chlorosilane carbon removal process, comprising a crude rectification unit, an extraction rectification unit, a back-extraction rectification unit, a chlorosilane recovery unit, and a carbon-containing organic matter collection unit.

[0008] The extraction rectification unit comprises an extraction tank and a first rectification column, the inlet of the extraction tank is connected to the outlet of the crude rectification unit, and the outlet of the extraction tank is connected to the inlet of the first rectification column.

[0009] The stripping rectification unit comprises a buffer stirred tank and a second rectification tower, an inlet of the buffer stirred tank is connected with a tower bottom outlet of the first rectification tower, and an outlet of the buffer stirred tank is connected with an inlet of the second rectification tower.

[0010] The tower top outlet of the first rectification tower is connected with a first cooler, a first reflux drum and the chlorosilane recovery unit in sequence, and the tower top outlet of the second rectification tower is connected with a second cooler, a second reflux drum and the carbon-containing organic matter collecting unit in sequence.

[0011] Preferably, the system further comprises an extractant conveying unit and a stripping agent conveying unit, the extractant conveying unit is connected with the inlet of the extraction tank, and the stripping agent conveying unit is connected with the buffer stirred tank.

[0012] Preferably, the tower bottom outlet of the second rectification tower is connected with a collecting tank.

[0013] Preferably, the outlet of the first reflux drum is connected with the tower top of the first rectification tower through a reflux pipe, and the outlet of the second reflux drum is connected with the tower top of the second rectification tower through a reflux pipe.

[0014] Preferably, the extraction tank and the first rectification tower, and the buffer stirred tank and the second rectification tower are connected through conveying pipelines, and a pressurizing pump is arranged on each of the conveying pipelines and the outlet pipeline of the first reflux drum.

[0015] Preferably, the first rectification tower and the second rectification tower are internally divided into rectification sections and stripping sections from top to bottom in sequence, and each of the rectification sections and the stripping sections is provided with a packing.

[0016] Preferably, the packing is a structured packing, and the structured packing comprises one or more combinations of a silk screen corrugation, a hole plate corrugation and a grid packing.

[0017] Compared with the prior art, the system has the beneficial effects that: the carbon-containing organic matter is dissolved in the extractant, the chlorosilane is rectified and purified by using the difference in volatility between the extractant and the chlorosilane, the separation and purification of the chlorosilane and the carbon-containing organic matter are easily realized, the light component chlorosilane can be recycled and reused, the loss of silicon and chlorine elements is reduced, the carbon-containing organic matter is separated from the extractant through stripping and rectification, the carbon-containing organic matter is collected for next treatment, the extractant is recycled and reused, the resource loss of the chlorosilane in the carbon removal process is reduced, the production cost is reduced, the system is suitable for large-scale industrial production, and is worth popularizing and using. BRIEF DESCRIPTION OF DRAWINGS

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the system for reducing energy loss during the decarbonization process of chlorosilanes provided by this utility model.

[0020] Figure descriptions: 101, Extraction tank; 102, First distillation column; 103, First cooler; 104, First reflux tank; 201, Buffer stirring tank; 202, Second distillation column; 203, Second cooler; 204, Second reflux tank; 30, Collection tank; 40, Pressure pump; 50, Extractant delivery unit; 60, Back-extraction agent delivery unit. Detailed Implementation

[0021] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0022] In the description of this utility model, it should be understood that the terms "upper", "lower", "inner", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this utility model and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] In this utility model, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] The following disclosure provides many different embodiments or examples for implementing various structures of this invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0026] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0027] Figure 1 This is a schematic diagram of the system for reducing energy loss during the decarbonization process of chlorosilanes provided by this utility model. The system includes a crude distillation unit, an extractive distillation unit, a back-extraction distillation unit, a chlorosilane recovery unit, and a carbon-containing organic matter collection unit.

[0028] The extractive distillation unit includes an extraction tank 101 and a first distillation column 102. The inlet of the extraction tank 101 is connected to the outlet of the crude distillation unit, and the outlet of the extraction tank 101 is connected to the inlet of the first distillation column 102.

[0029] The back-extraction distillation unit includes a buffer stirred tank 201 and a second distillation column 202. The inlet of the buffer stirred tank 201 is connected to the bottom outlet of the first distillation column 102, and the outlet of the buffer stirred tank 201 is connected to the inlet of the second distillation column 202.

[0030] The top outlet of the first distillation column 102 is sequentially connected to a first cooler 103, a first reflux tank 104, and a chlorosilane recovery unit, while the top outlet of the second distillation column 202 is sequentially connected to a second cooler 203, a second reflux tank 204, and a carbonaceous organic matter collection unit.

[0031] Specifically, the first distillation column 102 and the second distillation column 202 are divided into a rectification section and a stripping section from top to bottom. Both the rectification section and the stripping section are equipped with packing material, which can increase the turbulence of the liquid to facilitate heat transfer.

[0032] More specifically, the packing material is a structured packing material, including one or more combinations of wire mesh corrugated, perforated plate corrugated, and grid packing materials.

[0033] In operation, the carbon-containing chlorosilanes after crude distillation in the crude distillation unit are conveyed to the extraction tank 101. An appropriate amount of extractant is added to the extraction tank 101 to dissolve the carbon-containing organic matter in the extractant, thereby obtaining a mixture of chlorosilanes and extract. The mixture of chlorosilanes and extract is then conveyed to the first distillation column 102 for distillation purification to obtain a gaseous light component chlorosilane and extract. The gaseous light component chlorosilane is cooled to obtain a liquid phase chlorosilane, which is then recovered and reused. The extract is conveyed to the buffer stirred tank 201, where an appropriate amount of back-extraction agent is added to obtain a back-extraction liquid. The back-extraction liquid is then conveyed to the second distillation column 202 for distillation purification to obtain a liquid phase extractant and a gaseous carbon-containing organic matter. The gaseous carbon-containing organic matter is cooled to obtain a liquid phase carbon-containing organic matter. The liquid phase carbon-containing organic matter and liquid phase extractant are collected separately for further processing.

[0034] Specifically, the bottom outlet of the second distillation column 202 is connected to a collection tank 30 for collecting the liquid extractant and recycling it.

[0035] By dissolving carbon-containing organic matter in an extractant and utilizing the difference in volatility between the extractant and chlorosilanes for distillation purification, the separation and purification of chlorosilanes and carbon-containing organic matter can be easily achieved. This allows for the recovery and reuse of light-weight chlorosilane components, reducing the loss of silicon and chlorine. Further back-extraction and distillation separate the carbon-containing organic matter from the extractant, collecting the organic matter for further processing and recovering and reusing the extractant. This reduces resource consumption during carbon removal from chlorosilanes and lowers production costs. This system is suitable for large-scale industrial production and is worthy of widespread application.

[0036] It should be noted that the collected carbon-containing organic matter can be sold externally, thereby further reducing the carbon removal cost of chlorosilanes.

[0037] Since the production process is continuous, it is necessary to ensure the continuous input of extractant and back-extractant. The system also includes an extractant delivery unit 50 and a back-extractant delivery unit 60. The extractant delivery unit 50 is connected to the inlet of the extraction tank 101, and the back-extractant delivery unit 60 is connected to the buffer stirring tank 201.

[0038] In actual use, the outlet of the first reflux tank 104 is connected to the rectification section of the first distillation column 102 through a reflux pipe, and the outlet of the second reflux tank 204 is connected to the rectification section of the second distillation column 202 through a reflux pipe. In this way, the condensed liquid portion is taken out as the product, and the other portion is pumped back into the top of the distillation column as reflux liquid to increase the gas-liquid contact area and time in the column, thereby improving the separation efficiency.

[0039] In this embodiment, the cooling medium used by the first cooler 103 and the second cooler 203 is cooling circulating water.

[0040] Furthermore, the extraction tank 101 and the first distillation column 102, as well as the buffer stirring tank 201 and the second distillation column 202, are all connected by conveying pipelines. Each of these conveying pipelines and the outlet pipeline of the first reflux tank 104 is equipped with a pressure pump 40 to control the flow of liquid.

[0041] It should be noted that during distillation purification, the pressure and temperature ranges within the first distillation column 102 and the second distillation column 202 should be reasonably controlled according to the content of carbonaceous organic matter.

[0042] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A system for reducing energy loss during the carbon removal process of chlorosilanes, comprising a crude distillation unit, an extractive distillation unit, a back-extraction distillation unit, a chlorosilane recovery unit, and a carbonaceous organic matter collection unit, characterized in that: The extraction distillation unit includes an extraction tank (101) and a first distillation column (102). The inlet of the extraction tank (101) is connected to the outlet of the crude distillation unit, and the outlet of the extraction tank (101) is connected to the inlet of the first distillation column (102). The back-extraction distillation unit includes a buffer stirred tank (201) and a second distillation column (202). The inlet of the buffer stirred tank (201) is connected to the bottom outlet of the first distillation column (102), and the outlet of the buffer stirred tank (201) is connected to the inlet of the second distillation column (202). The first distillation column (102) is connected in sequence to a first cooler (103), a first reflux tank (104) and the chlorosilane recovery unit at its top outlet, and the second distillation column (202) is connected in sequence to a second cooler (203), a second reflux tank (204) and the carbonaceous organic matter collection unit at its top outlet.

2. The system for reducing energy loss during the decarbonization process of chlorosilanes according to claim 1, characterized in that, It also includes an extractant delivery unit (50) and a back-extractant delivery unit (60), the extractant delivery unit (50) being connected to the inlet of the extraction tank (101), and the back-extractant delivery unit (60) being connected to the buffer stirring tank (201).

3. The system for reducing energy loss during the decarbonization process of chlorosilanes according to claim 1, characterized in that: The bottom outlet of the second distillation column (202) is connected to a collection tank (30).

4. The system for reducing energy loss during the decarbonization process of chlorosilanes according to claim 1, characterized in that: The outlet of the first reflux tank (104) is connected to the top of the first distillation column (102) through a reflux pipe, and the outlet of the second reflux tank (204) is connected to the top of the second distillation column (202) through a reflux pipe.

5. The system for reducing energy loss during the decarbonization process of chlorosilanes according to claim 1, characterized in that: The extraction tank (101) and the first distillation column (102), as well as the buffer stirring tank (201) and the second distillation column (202), are connected by conveying pipelines. Each conveying pipeline and the outlet pipeline of the first reflux tank (104) is equipped with a pressure pump (40).

6. The system for reducing energy loss during the decarbonization process of chlorosilanes according to claim 1, characterized in that: The first distillation column (102) and the second distillation column (202) are divided into a rectification section and a stripping section from top to bottom, and both the rectification section and the stripping section are filled with packing.

7. The system for reducing energy loss during the decarbonization process of chlorosilanes according to claim 6, characterized in that: The packing material is a structured packing material, including one or more combinations of wire mesh corrugated, perforated plate corrugated, and grid packing.

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