A coupling system for chlorosilane purification

Abstract

The utility model discloses a kind of coupling systems of chlorosilane purification, including chlorosilane storage tank, complexing agent storage tank, complexing reaction kettle, reaction rectifying column, rectifying column overhead condenser, overhead production storage tank, adsorption column and high-purity chlorosilane storage tank.Advantages are in that: by the reaction rectifying column and chemical complexing agent separation tower coupling, B, P impurities in chlorosilane can be converted into high-boiling substance efficiently and economically, after rectifying column, it is separated from chlorosilane, realizes preliminary purification;B, P can be removed twice to chlorosilane after rectification purification by adsorption column, in addition to trace chemical complexing agent entrained in it also can play the adsorption effect, and then realize secondary purification;After reaction rectification, the tower kettle high-boiling substance containing chemical complexing agent is separated by chemical complexing agent separation tower, chemical complexing agent can be effectively recycled, and B, P impurities are taken out of chlorosilane.

Description

Technical Field

[0001] This utility model relates to the field of polycrystalline silicon production, specifically to a coupling system for purifying chlorosilanes. Background Technology

[0002] Chlorosilanes are key materials for producing high-quality silicon wafers, and their quality directly affects the performance and yield of integrated circuits. Due to the influence of raw materials and production processes, chlorosilanes may contain trace amounts of boron compounds such as BCl3 and phosphorus compounds such as PCl3 and PCl5. Since the boiling points of these impurities are close to those of chlorosilanes, they are difficult to remove efficiently using conventional physical methods.

[0003] Currently, the main methods used to remove trace amounts of boron (B) and phosphorus (P) impurities from chlorosilanes are multi-stage distillation and adsorption column adsorption. The main process involves distilling chlorosilanes produced by cold hydrogenation to separate a stream high in B and P content. This high-impurity stream is then passed through an adsorption column containing an adsorbent capable of adsorbing B and P impurities. Because the volatility of trace boron and phosphorus impurities in chlorosilanes is close to that of the chlorosilanes themselves, it is necessary to increase the reflux ratio and reduce the yield during multi-stage distillation to maintain quality indicators. This results in low product yield and unstable product quality, and the energy consumption and cost for boron and phosphorus removal remain high. Furthermore, the high-impurity chlorosilane stream passing through the adsorption column shortens the adsorbent's lifespan, increasing costs.

[0004] The invention patent application CN119100401A, entitled "Trichlorosilane Purification System and Method in Polycrystalline Silicon Production," describes a purification method where a chlorosilane stream containing B and P impurities is first purified by an adsorption device, followed by purification through chemical complexation. However, due to the high cost of adsorbents, this method increases production costs. Furthermore, chemical complexing agents are typically organic compounds that may decompose during high-temperature and high-pressure distillation. Therefore, the chemically complexed chlorosilane stream may contain impurities. Directly collecting the chlorosilane after chemical complexation purification poses a risk of chemical complexing agent contamination. Moreover, the lack of a chemical complexing agent recovery and treatment device results in waste and pollution, which is inconsistent with green production. Therefore, this method has room for improvement in terms of economics and technical feasibility. Utility Model Content

[0005] In order to solve the above problems, the purpose of this utility model is to provide a coupling system for the purification of chlorosilanes.

[0006] This utility model is implemented by the following technical solution: A coupled system for chlorosilane purification includes a chlorosilane storage tank, a complexing agent storage tank, a complexing reaction vessel, a reactive distillation column, a distillation column top condenser, a top product storage tank, an adsorption column, and a high-purity chlorosilane storage tank. The outlet of the chlorosilane storage tank is connected to the inlet of the first delivery pump via a pipeline. The outlet of the complexing agent storage tank is connected to the inlet of the feeding vessel via a pipeline. The outlets of the first delivery pump and the feeding vessel are both connected to the inlet of the complexing reactor via pipelines. The outlet of the complexing reactor is connected to the inlet of the reactive distillation column via a pipeline. The top outlet of the reactive distillation column is connected to the inlet of the top condenser of the distillation column via a pipeline. The outlet of the top condenser of the distillation column is connected to the inlet of the top collection storage tank via a pipeline. The outlet of the top collection storage tank is connected to the inlet of the second delivery pump via a pipeline. The outlet of the second delivery pump is connected to the bottom inlet of the adsorption column via a pipeline. The top outlet of the adsorption column is connected to the inlet of the high-purity chlorosilane storage tank via a pipeline.

[0007] Furthermore, it also includes a reboiler at the bottom of the distillation column, wherein the bottom outlet of the reactive distillation column is connected to the inlet of the reboiler at the bottom of the distillation column via a pipeline, and the outlet of the reboiler at the bottom of the distillation column is connected to the lower middle part of the reactive distillation column via a pipeline.

[0008] Furthermore, the outlet of the top condenser of the distillation column is also connected to the upper liquid inlet of the reactive distillation column via a pipeline.

[0009] Furthermore, it also includes a chemical complexing agent separation tower, a condenser at the top of the separation tower, and a high-boiling complexing agent storage tank; The bottom outlet of the reactive distillation column is connected to the inlet of the chemical complexing agent separation column via a pipeline, the top outlet of the chemical complexing agent separation column is connected to the inlet of the top condenser of the separation column via a pipeline, and the outlet of the top condenser of the separation column is connected to the inlet of the top collection storage tank via a pipeline.

[0010] Furthermore, it also includes a reboiler for the bottom of the separation tower. The bottom outlet of the chemical complexing agent separation tower is connected to the inlet of the reboiler for the bottom of the separation tower via a pipeline, and the outlet of the reboiler for the bottom of the separation tower is connected to the lower middle part of the chemical complexing agent separation tower via a pipeline.

[0011] Furthermore, the outlet of the condenser at the top of the separation tower is connected to the upper inlet of the chemical complexing agent separation tower via a pipeline.

[0012] Furthermore, the adsorption column is filled with an adsorbent, which is one of silica-alumina gel, activated carbon, and resin.

[0013] Advantages of this utility model: By coupling a reactive distillation column and a chemical complexing agent separation column, B and P impurities in chlorosilanes can be converted into high-boiling-point substances efficiently and economically. These substances are then separated from the chlorosilanes in the distillation column, achieving preliminary purification. An adsorption column can further remove B and P from the distilled chlorosilanes. Additionally, it can adsorb trace amounts of chemical complexing agents, thus achieving secondary purification. The high-boiling-point residue containing the chemical complexing agent in the bottom of the reactive distillation column is then separated by the chemical complexing agent separation column, effectively recovering the chemical complexing agent and carrying away the B and P impurities from the chlorosilanes. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the system connection in this embodiment.

[0015] In the diagram: 1. Chlorosilane storage tank; 2. First transfer pump; 3. Complexing agent storage tank; 4. Feeding vessel; 5. Complexing reaction vessel; 6. Reactive distillation column; 7. Distillation column top condenser; 8. Top product storage tank; 9. Second transfer pump; 10. Adsorption column; 11. High-purity chlorosilane storage tank; 12. Distillation column bottom reboiler; 13. Separation column bottom reboiler; 14. Chemical complexing agent separation column; 15. Separation column top condenser; 16. High-boiling complexing agent storage tank. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Example 1 like Figure 1 The coupled system for chlorosilane purification shown includes a chlorosilane storage tank 1, a complexing agent storage tank 3, a complexing reaction vessel 5, a reactive distillation column 6, a distillation column top condenser 7, a top product storage tank 8, an adsorption column 10, and a high-purity chlorosilane storage tank 11; it also includes a distillation column bottom reboiler 12, a separation column bottom reboiler 13, a chemical complexing agent separation column 14, a separation column top condenser 15, and a high-boiling complexing agent storage tank 16.

[0018] The outlet of the chlorosilane storage tank 1 is connected to the inlet of the first transfer pump 2 via a pipeline. The outlet of the complexing agent storage tank 3 is connected to the inlet of the feeding vessel 4 via a pipeline. The outlets of both the first transfer pump 2 and the feeding vessel 4 are connected to the inlet of the complexing reactor 5 via pipelines. The outlet of the complexing reactor 5 is connected to the inlet of the reactive distillation column 6 via a pipeline. The bottom outlet of the reactive distillation column 6 is connected to the inlet of the reboiler 12 at the bottom of the distillation column via a pipeline. The outlet of the reboiler 12 at the bottom of the distillation column is connected to the lower middle section of the reactive distillation column 6 via a pipeline. The bottom outlet of the reactive distillation column 6 is connected to the inlet of the chemical complexing agent separation column 14 via a pipeline. The top outlet of the chemical complexing agent separation column 14 is connected to the inlet of the top condenser 15 at the top of the separation column via a pipeline. The outlet of the top condenser 15 at the top of the separation column is connected to the inlet of the top collection storage tank 8 via a pipeline. The top outlet of the reactive distillation column 6 is connected to the inlet of the top condenser 7 of the distillation column via a pipeline. The outlet of the top condenser 7 of the distillation column is connected to the inlet of the top collection storage tank 8 via a pipeline. The outlet of the top collection storage tank 8 is connected to the inlet of the second transfer pump 9 via a pipeline. The outlet of the second transfer pump 9 is connected to the bottom inlet of the adsorption column 10 via a pipeline. The top outlet of the adsorption column 10 is connected to the inlet of the high-purity chlorosilane storage tank 11 via a pipeline.

[0019] The bottom outlet of the chemical complexing agent separation tower 14 is connected to the inlet of the reboiler 13 of the separation tower via a pipeline, and the outlet of the reboiler 13 of the separation tower is connected to the middle and lower part of the chemical complexing agent separation tower 14 via a pipeline.

[0020] The outlet of the top condenser 7 of the distillation column is also connected to the upper inlet of the reactive distillation column 6 via a pipeline. The outlet of the top condenser 15 of the separation column is also connected to the upper inlet of the chemical complexing agent separation column 14 via a pipeline.

[0021] In this embodiment, the adsorption column 10 is filled with an adsorbent, which is one of the following: silica-alumina gel, activated carbon, or resin (polycrystalline silicon disproportionation resin, mainly a styrene skeleton, modified with tertiary amine functional groups). The complexing agent stored in the complexing agent storage tank 3 has functional groups that play a major complexing role, namely -SH, -NH, -O-, -OH, =S, -COH, =N-, glucose or other sugars and their derivatives; the ratio of the above functional groups to the B and P impurities in the chlorosilane is 100~1:1.

[0022] Working principle: The chlorosilane in the chlorosilane storage tank 1 (the composition of the chlorosilane is: trichlorosilane content between 45% and 99%, silicon tetrachloride between 0 and 45%, dichlorosilane between 0 and 10%, of which B content is between 0.0001 and 3 mg / L and P content is between 0.0001 and 2 mg / L) is transported to the complexing reactor 5 through the first transfer pump 2. At the same time, the complexing agent in the complexing agent storage tank 3 enters the complexing reactor 5 through the feed vessel 4. The two undergo sufficient contact and complexation, converting B and P in the chlorosilane into high-boiling substances.

[0023] After the reaction is completed, the chlorosilane enters the reactive distillation column 6 through the outlet of the complexation reactor 5. After distillation, the chlorosilane stream that has been preliminarily removed from B and P impurities is separated at the top of the column. Its composition is 99% gaseous trichlorosilane. After passing through the condenser 7 at the top of the distillation column, it is converted into liquid trichlorosilane and then enters the top collection and storage tank 8.

[0024] The preliminarily purified trichlorosilane stored in the top-of-the-column storage tank 8 is fed into the adsorption column 10 via the second transfer pump 9. The trichlorosilane liquid is adsorbed and purified by the adsorbent packed inside, resulting in high-purity trichlorosilane, which is then temporarily stored in the high-purity chlorosilane storage tank 11.

[0025] After preliminary purification, the high-boiling-point substance from the bottom of the column containing the chemical complexing agent enters the chemical complexing agent separation column 14. The chlorosilane collected from the top of the chemical complexing agent separation column 14 is condensed by the top condenser 15 and enters the top collection storage tank 8. The high-boiling-point substance collected from the bottom of the chemical complexing agent separation column 14 enters the high-boiling-point complexing agent storage tank 16, which can realize the separation of chemical complexing agent and B and P.

[0026] In this embodiment, the temperature of the complexing reactor 5 is controlled at 0-100℃, the pressure at 100-600kPa, and the reaction time is 0.5-3h; the pressure of the reactive distillation column 6 is controlled at 100-700kPa, and the temperature at 60-120℃; the pressure of the chemical complexing agent separation column 14 is controlled at 200-600kPa, and the temperature at 63-125℃; and the temperature of the adsorption column 10 is controlled at 0-80℃, and the pressure at 300-700kPa.

[0027] The chlorosilane purification system of this embodiment employs a purification system coupled with complexation reaction, distillation, and adsorption phases. It uses a chemical complexing agent to react with B and P metal impurities, generating chemicals with higher boiling points. These impurities are then further separated from the chlorosilanes via a reactive distillation column 6, followed by secondary adsorption purification of B and P via an adsorption column 10. The complexing agent used in this embodiment has a complexing effect on boron, phosphorus, and metal impurities, but does not react with chlorosilanes. This embodiment can achieve a removal efficiency of up to 80% for phosphorus impurities and up to 90% for boron impurities in chlorosilanes.

[0028] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A coupling system for purifying chlorosilanes, characterized in that, This includes chlorosilane storage tanks, complexing agent storage tanks, complexing reaction vessels, reactive distillation columns, distillation column top condensers, top product storage tanks, adsorption columns, high-purity chlorosilane storage tanks, chemical complexing agent separation columns, separation column top condensers, and high-boiling complexing agent storage tanks. The outlet of the chlorosilane storage tank is connected to the inlet of the first delivery pump via a pipeline. The outlet of the complexing agent storage tank is connected to the inlet of the feeding vessel via a pipeline. The outlets of the first delivery pump and the feeding vessel are both connected to the inlet of the complexing reactor via pipelines. The outlet of the complexing reactor is connected to the inlet of the reactive distillation column via a pipeline. The top outlet of the reactive distillation column is connected to the inlet of the top condenser of the distillation column via a pipeline. The outlet of the top condenser of the distillation column is connected to the inlet of the top collection storage tank via a pipeline. The outlet of the top collection storage tank is connected to the inlet of the second delivery pump via a pipeline. The outlet of the second delivery pump is connected to the bottom inlet of the adsorption column via a pipeline. The top outlet of the adsorption column is connected to the inlet of the high-purity chlorosilane storage tank via a pipeline. The bottom outlet of the reactive distillation column is connected to the inlet of the chemical complexing agent separation column via a pipeline, the top outlet of the chemical complexing agent separation column is connected to the inlet of the top condenser of the separation column via a pipeline, and the outlet of the top condenser of the separation column is connected to the inlet of the top collection storage tank via a pipeline.

2. The coupling system for chlorosilane purification according to claim 1, characterized in that, It also includes a reboiler at the bottom of a distillation column, wherein the bottom outlet of the reactive distillation column is connected to the inlet of the reboiler at the bottom of the distillation column via a pipeline, and the outlet of the reboiler at the bottom of the distillation column is connected to the lower middle part of the reactive distillation column via a pipeline.

3. The coupling system for chlorosilane purification according to claim 1, characterized in that, The outlet of the top condenser of the distillation column is also connected to the upper liquid inlet of the reactive distillation column via a pipeline.

4. The coupling system for chlorosilane purification according to claim 1, characterized in that, It also includes a reboiler at the bottom of the separation tower. The bottom outlet of the chemical complexing agent separation tower is connected to the inlet of the reboiler at the bottom of the separation tower via a pipeline, and the outlet of the reboiler at the bottom of the separation tower is connected to the lower middle part of the chemical complexing agent separation tower via a pipeline.

5. The coupling system for chlorosilane purification according to claim 1, characterized in that, The outlet of the condenser at the top of the separation tower is also connected to the upper inlet of the chemical complexing agent separation tower via a pipeline.

6. The coupling system for chlorosilane purification according to claim 1, characterized in that, The adsorption column is filled with an adsorbent, which is one of silica-alumina gel, activated carbon, and resin.

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