Cold hydrogenation production system and cold hydrogenation production process

Abstract

The application discloses a cold hydrogenation production system and a cold hydrogenation production process. The system comprises an electric heater, a reactor connected with the electric heater, hydrogen and silicon tetrachloride reacting in the reactor to generate trichlorosilane and hydrogen chloride, a tail gas heat exchanger connected with the reactor, tail gas flowing out of the reactor being heat-exchanged with hydrogen and silicon tetrachloride flowing out of the heat exchanger in the tail gas heat exchanger, the tail gas heat exchanger being further connected with the electric heater, hydrogen and silicon tetrachloride being heat-exchanged in the tail gas heat exchanger flowing into the electric heater, a silicon powder filter connected with the tail gas heat exchanger, a heat exchanger connected with the tail gas heat exchanger, the heat exchanger being further connected with the silicon powder filter, and a vaporizer connected with the heat exchanger. The application fully utilizes heat through heat exchange, reduces the load of a heater of a material pretreatment system, fully utilizes surplus heat in the system, optimizes process parameters, reduces the consumption of system power, and greatly reduces the production cost of polysilicon.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polysilicon production, and particularly relates to a cold hydrogenation production system and a cold hydrogenation production process. BACKGROUND

[0002] With the gradual depletion of fossil energy and the increasing environmental pollution, it is urgent to explore a pollution-free renewable energy. As the most abundant renewable energy, solar energy has the advantages of cleanliness, safety, universality, resource sufficiency and potential economy compared with other energies. Fully utilizing solar energy has important economic and strategic significance for realizing sustainable development in a low-carbon mode. Trichlorosilane is an important raw material for producing polysilicon. With the wide application of polysilicon in modern science and technology, national defense and industry, the production of trichlorosilane has also developed rapidly. Improving product quality, reducing production cost and ensuring safety production have become the goals pursued by various manufacturers. Although various manufacturers have continuously researched and explored the synthesis process of trichlorosilane, the reduction of production cost has little effect. At the same time, during the operation of the equipment, the heat conducting oil heat exchanger column leaks and the heat conducting oil catches fire, which causes great safety hazards in the synthesis process of trichlorosilane. Therefore, it is imperative to further optimize the synthesis process of trichlorosilane. SUMMARY

[0003] The technical problem to be solved by the application is to provide a cold hydrogenation production system and a cold hydrogenation production process, which fully utilize the excess heat in the system and reduce the consumption of system power.

[0004] The technical solution adopted to solve the technical problem of the application is to provide a cold hydrogenation production system, which comprises:

[0005] An electric heater is used to heat hydrogen and silicon tetrachloride flowing into a reactor;

[0006] The reactor is connected with the electric heater, and hydrogen and silicon tetrachloride react in the reactor to generate trichlorosilane and hydrogen chloride;

[0007] A tail gas heat exchanger is connected with the reactor, and the tail gas flowing out of the reactor exchanges heat with hydrogen and silicon tetrachloride flowing out of the heat exchanger in the tail gas heat exchanger. The tail gas heat exchanger is also connected with the electric heater, and hydrogen and silicon tetrachloride that have finished heat exchange in the tail gas heat exchanger flow into the electric heater;

[0008] A silicon powder filter is connected with the tail gas heat exchanger, and the tail gas flowing out of the tail gas heat exchanger flows into the silicon powder filter to remove silicon powder;

[0009] A heat exchanger is connected with the tail gas heat exchanger, and the heat exchanger is also connected with the silicon powder filter. Hydrogen and silicon tetrachloride flowing into the heat exchanger from the vaporizer are exchanged with the gas flowing into the heat exchanger from the silicon powder filter.

[0010] A vaporizer is connected with the heat exchanger, and the vaporizer is used for introducing hydrogen and silicon tetrachloride to be vaporized.

[0011] Preferably, the tail gas heat exchanger comprises:

[0012] A tail gas primary heat exchanger is connected with the reactor, and the tail gas flowing out of the reactor is exchanged with hydrogen and silicon tetrachloride flowing out of the tail gas secondary heat exchanger in the tail gas primary heat exchanger.

[0013] A tail gas secondary heat exchanger is connected with the tail gas primary heat exchanger, and the tail gas flowing out of the tail gas primary heat exchanger is exchanged with hydrogen and silicon tetrachloride flowing out of the heat exchanger in the tail gas secondary heat exchanger.

[0014] Preferably, the cold hydrogenation production system further comprises:

[0015] A washing tower is connected with the heat exchanger, and the washing tower is used for washing the material flowing into the heat exchanger from the silicon powder filter after heat exchange by trichlorosilane to remove silicon powder.

[0016] Preferably, the cold hydrogenation production system further comprises:

[0017] A static mixer is connected with the vaporizer, and the static mixer is used for mixing hydrogen and silicon tetrachloride preheated by the silicon tetrachloride preheater, and the mixture flows into the vaporizer.

[0018] A silicon tetrachloride preheater is connected with the static mixer, and the silicon tetrachloride preheater is used for preheating silicon tetrachloride.

[0019] Preferably, the cold hydrogenation production system further comprises:

[0020] A multi-effect heat exchanger is connected with the washing tower, and the multi-effect heat exchanger is also connected with the silicon tetrachloride preheater and used for introducing silicon tetrachloride into the silicon tetrachloride preheater. The multi-effect heat exchanger is also connected with the static mixer and used for introducing hydrogen into the static mixer. The multi-effect heat exchanger is used for introducing hydrogen and silicon tetrachloride respectively, and the hydrogen and silicon tetrachloride introduced into the multi-effect heat exchanger are exchanged by the tail gas flowing through the washing tower.

[0021] Preferably, the cold hydrogenation production system further comprises:

[0022] A silicon powder collecting tank is connected with the silicon powder filter, and the silicon powder collecting tank is used for collecting silicon powder filtered by the silicon powder filter. The silicon powder collecting tank is also connected with the reactor, and hydrogen and silicon powder are exchanged in the silicon powder collecting tank. The exchanged hydrogen flows into the reactor to purge the material in the reactor.

[0023] A hydrogen preheater is connected to the silicon powder collecting tank, and the hydrogen preheater is used for preheating hydrogen.

[0024] Preferably, the cold hydrogenation production system further comprises:

[0025] A silicon powder storage tank is connected to the silicon powder collecting tank, and the silicon powder storage tank is also connected to the reactor, and the silicon powder storage tank is used for collecting silicon powder flowing into the silicon powder storage tank and the reactor.

[0026] The application also provides a cold hydrogenation production process for the cold hydrogenation production system, comprising the following steps:

[0027] The hydrogen and silicon tetrachloride are introduced into the vaporizer for vaporization;

[0028] The hydrogen and silicon tetrachloride flowing into the heat exchanger from the vaporizer are heat-exchanged with the gas flowing into the heat exchanger from the silicon powder filter;

[0029] The tail gas flowing out of the reactor is heat-exchanged with the hydrogen and silicon tetrachloride flowing out of the heat exchanger in the tail gas heat exchanger, and the hydrogen and silicon tetrachloride after heat exchange in the tail gas heat exchanger are introduced into the electric heater;

[0030] The tail gas flowing out of the tail gas heat exchanger is introduced into the silicon powder filter to remove silicon powder;

[0031] The hydrogen and silicon tetrachloride introduced into the reactor are heated by the electric heater;

[0032] The hydrogen and silicon tetrachloride heated by the electric heater are introduced into the reactor to react to generate trichlorosilane and hydrogen chloride.

[0033] Preferably, the cold hydrogenation production process for the cold hydrogenation production system uses the cold hydrogenation production system, and further comprises the following steps:

[0034] The tail gas flowing out of the reactor is heat-exchanged with the hydrogen and silicon tetrachloride flowing out of the tail gas secondary heat exchanger in the tail gas primary heat exchanger, and the temperature of the hydrogen and silicon tetrachloride after heat exchange is 300-350℃;

[0035] The tail gas flowing out of the tail gas primary heat exchanger is heat-exchanged with the hydrogen and silicon tetrachloride flowing out of the heat exchanger in the tail gas secondary heat exchanger, and the temperature of the hydrogen and silicon tetrachloride after heat exchange is 420-450℃.

[0036] Preferably, the cold hydrogenation production process for the cold hydrogenation production system uses the cold hydrogenation production system, and further comprises the following steps:

[0037] The hydrogen and silicon tetrachloride after heat exchange in the multi-effect heat exchanger have a temperature of 120-150℃;

[0038] The preheated silicon tetrachloride has a temperature of 170-180℃ after being preheated by the silicon tetrachloride preheater.

[0039] The cold hydrogenation production system and the cold hydrogenation production process in the application fully utilize heat through heat exchange, reduce the load of the heater of the material pretreatment system, reduce the power consumption of the cold hydrogenation workshop from 0.34 degrees / kg.TCS to 0.2 degrees / kg.TCS (TCS is the abbreviation of trichlorosilane), fully utilize the surplus heat in the system, optimize the process parameters, reduce the consumption of system power, and greatly reduce the production cost of polysilicon. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 Fig. 2 is a structural schematic diagram of the cold hydrogenation production system in the embodiment 2 of the application.

[0041] In the figure, 1 is a multi-effect heat exchanger, 2 is a silicon tetrachloride preheater, 3 is a hydrogen preheater, 4 is a static mixer, 5 is a vaporizer, 6 is an electric heater, 7 is a reactor, 8 is a tail gas primary heat exchanger, 9 is a tail gas secondary heat exchanger, 10 and 11 are silicon powder filters, 12 is a heat exchanger, 13 is a washing tower, 14 is a silicon powder collection tank, 15 is a silicon powder storage tank, 16 is an air cooling tower, 17 is hydrogen, and 18 is silicon tetrachloride. DETAILED DESCRIPTION

[0042] In order for those skilled in the art to better understand the technical solutions of the application, the application will be further described in detail below in combination with the drawings and specific embodiments.

[0043] The embodiments of the application are described in detail below, and examples of the embodiments are shown in the drawings, in which the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the application, and cannot be understood as a limitation on the application.

[0044] Embodiment 1

[0045] The embodiment provides a cold hydrogenation production system, which comprises:

[0046] An electric heater is used to heat the hydrogen and the silicon tetrachloride flowing into the reactor.

[0047] A reactor is connected with the electric heater, and the hydrogen and the silicon tetrachloride react in the reactor to generate trichlorosilane and hydrogen chloride.

[0048] A tail gas heat exchanger is connected with the reactor, and the tail gas flowing out of the reactor exchanges heat with the hydrogen and the silicon tetrachloride flowing out of the heat exchanger in the tail gas heat exchanger. The tail gas heat exchanger is also connected with the electric heater, and the hydrogen and the silicon tetrachloride after heat exchange in the tail gas heat exchanger flow into the electric heater.

[0049] A silicon powder filter is connected with the tail gas heat exchanger, and the tail gas flowing out of the tail gas heat exchanger is filtered into the silicon powder filter to remove silicon powder;

[0050] A heat exchanger is connected with the tail gas heat exchanger, and the heat exchanger is also connected with the silicon powder filter. Hydrogen and silicon tetrachloride flowing into the heat exchanger from the vaporizer are heat exchanged with the gas flowing into the heat exchanger from the silicon powder filter;

[0051] A vaporizer is connected with the heat exchanger, and the vaporizer is used for flowing in hydrogen and silicon tetrachloride to be vaporized.

[0052] The embodiment also provides a cold hydrogenation production process used by the cold hydrogenation production system.

[0053] Hydrogen and silicon tetrachloride are vaporized in the vaporizer;

[0054] Hydrogen and silicon tetrachloride flowing into the heat exchanger from the vaporizer are heat exchanged with the gas flowing into the heat exchanger from the silicon powder filter;

[0055] The tail gas flowing out of the reactor is heat exchanged with hydrogen and silicon tetrachloride flowing out of the heat exchanger in the tail gas heat exchanger, and hydrogen and silicon tetrachloride heat exchanged in the tail gas heat exchanger flow into the electric heater;

[0056] The tail gas flowing out of the tail gas heat exchanger is filtered into the silicon powder filter to remove silicon powder;

[0057] Hydrogen and silicon tetrachloride flowing into the reactor are heated by the electric heater;

[0058] Hydrogen and silicon tetrachloride heated by the electric heater flow into the reactor to react to generate trichlorosilane and hydrogen chloride.

[0059] The cold hydrogenation production system and the cold hydrogenation production process in the embodiment fully utilize heat through heat exchange, reduce the load of the heater of the material pretreatment system, fully utilize the surplus heat in the system, optimize the process parameters, reduce the consumption of system power, and greatly reduce the production cost of polysilicon.

[0060] Embodiment 2

[0061] As shown in Figure 1 The embodiment provides a cold hydrogenation production system, which comprises:

[0062] An electric heater 6 is used for heating hydrogen and silicon tetrachloride flowing into a reactor 7;

[0063] The reactor 7 is connected with the electric heater 6, and hydrogen and silicon tetrachloride react in the reactor 7 to generate trichlorosilane and hydrogen chloride;

[0064] The tail gas heat exchanger is connected with the reactor 7, the tail gas flowing out of the reactor 7 exchanges heat with the hydrogen and silicon tetrachloride flowing out of the heat exchanger 12 in the tail gas heat exchanger, and the tail gas heat exchanger is also connected with the electric heater 6, the hydrogen and silicon tetrachloride after heat exchange in the tail gas heat exchanger flow into the electric heater 6;

[0065] The silicon powder filter 10 is connected with the tail gas heat exchanger, and the tail gas flowing out of the tail gas heat exchanger flows into the silicon powder filter 10 to remove the silicon powder;

[0066] The heat exchanger 12 is connected with the tail gas heat exchanger, the heat exchanger 12 is also connected with the silicon powder filter 10, the hydrogen and silicon tetrachloride flowing into the heat exchanger 12 from the vaporizer 5 exchanges heat with the gas flowing into the heat exchanger 12 from the silicon powder filter 10, and the heat exchanger 12 is also connected with the silicon powder filter 11;

[0067] The vaporizer 5 is connected with the heat exchanger 12, and the vaporizer 5 is used for flowing in the hydrogen and silicon tetrachloride to be vaporized.

[0068] Preferably, the tail gas heat exchanger comprises:

[0069] The tail gas primary heat exchanger 8 is connected with the reactor 7, the tail gas flowing out of the reactor 7 exchanges heat with the hydrogen and silicon tetrachloride flowing out of the tail gas secondary heat exchanger 9 in the tail gas primary heat exchanger 8, and the tail gas primary heat exchanger 8 is connected with the electric heater 6, and the hydrogen and silicon tetrachloride flowing out of the tail gas primary heat exchanger 8 flow into the electric heater 6.

[0070] The tail gas secondary heat exchanger 9 is connected with the tail gas primary heat exchanger 8, the tail gas flowing out of the tail gas primary heat exchanger 8 exchanges heat with the hydrogen and silicon tetrachloride flowing out of the heat exchanger 12 in the tail gas secondary heat exchanger 9, and the tail gas secondary heat exchanger 9 is connected with the silicon powder filter 10, and the reaction tail gas after heat exchange in the tail gas secondary heat exchanger 9 flows into the silicon powder filter 10.

[0071] Preferably, the cold hydrogenation production system further comprises:

[0072] The washing tower 13 is connected with the heat exchanger 12, and the washing tower 13 is used for washing the material flowing into the heat exchanger 12 after heat exchange by the silicon powder filter 10 by trichlorosilane to remove the silicon powder.

[0073] Preferably, the cold hydrogenation production system further comprises:

[0074] The static mixer 4 is connected with the vaporizer 5, and the static mixer 4 is used for mixing the hydrogen flowing in and the silicon tetrachloride preheated by the silicon tetrachloride preheater 2, and the mixture flows into the vaporizer 5;

[0075] The silicon tetrachloride preheater 2 is connected with the static mixer 4, and the silicon tetrachloride preheater 2 is used for preheating the silicon tetrachloride.

[0076] Preferably, the cold hydrogenation production system further comprises:

[0077] The multi-effect heat exchanger 1 is connected with the washing tower 13, and is also connected with the silicon tetrachloride preheater 2 for passing the silicon tetrachloride into the silicon tetrachloride preheater 2, and is also connected with the static mixer 4 for passing the hydrogen into the static mixer 4, and is used for passing the hydrogen and the silicon tetrachloride into the multi-effect heat exchanger 1 respectively, and the hydrogen and the silicon tetrachloride passing into the multi-effect heat exchanger 1 are heat-exchanged by the tail gas of the washing tower 13.

[0078] Preferably, the cold hydrogenation production system further comprises:

[0079] The silicon powder collecting tank 14 is connected with the silicon powder filter 10, and is used for collecting the silicon powder filtered by the silicon powder filter 10, and is also connected with the reactor 7, and the hydrogen and the silicon powder are heat-exchanged in the silicon powder collecting tank 14, and the heat-exchanged hydrogen flows into the reactor 7 to purge the materials in the reactor 7; and the silicon powder collecting tank 14 is connected with the silicon powder filter 11.

[0080] The hydrogen preheater 3 is connected with the silicon powder collecting tank 14, and is used for preheating the hydrogen.

[0081] Specifically, in the embodiment, the hydrogen preheater 3 is connected with the multi-effect heat exchanger 1, and the hydrogen is first passed into the multi-effect heat exchanger 1 to be heat-exchanged, and then is passed into the hydrogen preheater 3 to be preheated.

[0082] Preferably, the cold hydrogenation production system further comprises:

[0083] The silicon powder storage tank 15 is connected with the silicon powder collecting tank 14, and is also connected with the reactor 7, and is used for collecting the silicon powder flowing into the silicon powder storage tank 15 and the reactor 7.

[0084] The embodiment also provides a cold hydrogenation production process for the cold hydrogenation production system.

[0085] The hydrogen and the silicon tetrachloride are passed into the vaporizer 5 to be vaporized;

[0086] The hydrogen and the silicon tetrachloride flowing into the heat exchanger 12 from the vaporizer 5 are heat-exchanged with the gas flowing into the heat exchanger 12 from the silicon powder filter 10;

[0087] The tail gas flowing out of the reactor 7 is heat-exchanged with the hydrogen and the silicon tetrachloride flowing out of the heat exchanger 12 in the tail gas heat exchanger, and the hydrogen and the silicon tetrachloride heat-exchanged in the tail gas heat exchanger flow into the electric heater 6;

[0088] The tail gas flowing out of the tail gas heat exchanger is filtered in the silicon powder filter 10 to remove the silicon powder;

[0089] The hydrogen and silicon tetrachloride flowing into the reactor 7 are heated by the electric heater 6;

[0090] The hydrogen and silicon tetrachloride heated by the electric heater 6 are reacted to generate trichlorosilane and hydrogen chloride in the reactor 7.

[0091] Preferably, the cold hydrogenation production system uses the cold hydrogenation production process, and the cold hydrogenation production process using the cold hydrogenation production system further comprises the following steps:

[0092] The tail gas flowing out of the reactor 7 is exchanged with the hydrogen and silicon tetrachloride flowing out of the tail gas secondary heat exchanger 9 in the tail gas primary heat exchanger 8, and the temperature of the hydrogen and silicon tetrachloride after heat exchange is 300-350℃;

[0093] The tail gas flowing out of the tail gas primary heat exchanger 8 is exchanged with the hydrogen and silicon tetrachloride flowing out of the heat exchanger 12 in the tail gas secondary heat exchanger 9, and the temperature of the hydrogen and silicon tetrachloride after heat exchange is 420-450℃.

[0094] Preferably, the cold hydrogenation production system uses the cold hydrogenation production process, and the cold hydrogenation production process using the cold hydrogenation production system further comprises the following steps:

[0095] The hydrogen and silicon tetrachloride after heat exchange in the multi-effect heat exchanger 1 have a temperature of 120-150℃;

[0096] The silicon tetrachloride after preheating in the silicon tetrachloride preheater 2 has a temperature of 170-180℃.

[0097] The trichlorosilane synthesis system in the embodiment mainly further optimizes the existing trichlorosilane synthesis system, introduces the multi-effect heat exchanger 1, mainly utilizes the characteristics of the multi-effect heat exchanger 1, and simultaneously exchanges the hydrogen and the silicon tetrachloride by using the heat of the material flowing out of the washing tower 13 in the same multi-effect heat exchanger 1, thereby improving the utilization efficiency of the heat of the material flowing out of the washing tower 13. The hydrogen after heat exchange is used for pulse of the silicon powder filter 10 and purging of the reactor 7 leg, and forms a mixed gas with the silicon tetrachloride. The mixed gas enters the reactor 7 after three-stage heat exchange and one-stage heating. The tail gas generated by the reactor 7 enters the silicon powder filter 10 after two-stage heat exchange. After the silicon powder in the tail gas is filtered, the tail gas enters the subsequent system, thereby reducing the amount of silicon powder in the tail gas entering the subsequent system, improving the operation stability of the subsequent system, reducing the amount of silicon powder escaping, and further reducing the unit consumption of the silicon powder. In the specific cold hydrogenation process:

[0098] The pressurized hydrogen and the silicon tetrachloride are transported to the multi-effect heat exchanger 1, and the pressurized hydrogen and the silicon tetrachloride are exchanged by using the material flowing out of the washing tower 13;

[0099] The hydrogen after heat exchange in the multi-effect heat exchanger 1 is divided into three parts: one part is used as the pulse gas of the silicon powder filter 10, one part is used as the purge gas of the reactor 7 leg, and one part is mixed with silicon tetrachloride in the static mixer 4 to participate in the reaction as one of the reactants;

[0100] The silicon tetrachloride after heat exchange in the multi-effect heat exchanger 1 is mixed with the hydrogen after heat exchange in the static mixer 4, and then enters the reactor 7 to participate in the reaction after three-stage heat exchange and one-stage heating;

[0101] The tail gas of the reactor 7 is transported to the silicon powder filter (one standby) to filter the silicon powder in the tail gas, and then transported to the washing tower 13 for further washing, dust removal and cooling after secondary filtration;

[0102] The material at the top of the washing tower 13 is transported to the air cooling tower 16 and the post-cooling system after heat exchange with the hydrogen and silicon tetrachloride in the multi-effect heat exchanger 1, and the trichlorosilane is cooled in the air cooling tower 16, part of which is sent out, and the other part is sent to the washing tower 13 as washing liquid to remove the silicon powder.

[0103] Specifically, the material flow in the cold hydrogenation production system in the embodiment is as follows:

[0104] The hydrogen 17 with the pressure increased to 2.0-3.5 Mpa by the hydrogen compressor is transported to different pipe passes of the multi-effect heat exchanger 1 together with the silicon tetrachloride 18 with the pressure of 3.0-3.5 Mpa, and the hydrogen 17 and the silicon tetrachloride 18 in the multi-effect heat exchanger 1 are heat exchanged with the material (temperature: 160-180℃) at the outlet of the washing tower 13, and the temperature of the material at the outlet of the washing tower 13 is reduced to 130-150℃ after heat exchange with the hydrogen 17 and the silicon tetrachloride 18 in the multi-effect heat exchanger 1, and then enters the air cooling tower 16. The hydrogen 17 (temperature: 120-150℃) after heat exchange in the multi-effect heat exchanger 1 enters the hydrogen preheater 3, and the preheated hydrogen is transported to the silicon powder filter 10 to purge the filter element inside the silicon powder filter 10, which is used as the pulse gas of the silicon powder filter 10. The other part is transported to the inside of the reactor 7 as the purge hydrogen of the leg to purge the wing valve of the reactor 7 leg, so as to prevent the wing valve from not normally opening and closing and blocking the cyclone.

[0105] The silicon tetrachloride 18 (temperature 120-150 DEG C) after heat exchange by the multi-effect heat exchanger 1 is heated by 1.0 MPa steam (temperature 170-180 DEG C), mixed with hydrogen after heat exchange by the multi-effect heat exchanger 1 in the static mixer 4, and the mixed gas after heat exchange is sequentially passed through the shell side of the heat exchanger 12 at the inlet of the scrubbing tower 13, the tail gas secondary heat exchanger 9 (temperature of the mixed gas after heat exchange 300-350 DEG C), and the shell side of the tail gas primary heat exchanger 8 to exchange heat with the material at the outlet of the reactor 7, and then enters the electric heater 6 to be heated to 520-560 DEG C, and then enters the reactor 7 from the bottom of the reactor 7 to react in the reactor 7.

[0106] The tail gas after reaction with high-quality heat is sequentially passed through the tube side of the tail gas primary heat exchanger 8 and the tail gas secondary heat exchanger 9 to exchange heat with the hydrogen 17 and the mixer gas of the silicon tetrachloride 18, and then enters the silicon powder filter 10 (the silicon powder filter 10 and the silicon powder filter 11 are used alternately, and in this embodiment, the silicon powder filter 10 is used and the silicon powder filter 11 is standby) to filter the silicon powder in the tail gas, reduce the amount of silicon powder brought into the system, and improve the stability of the system, and the silicon powder filtered by the silicon powder filter 10 is transported to the silicon powder storage tank 15 after pressurization by the hydrogen 17, and then is recycled and reused after nitrogen replacement.

[0107] The tail gas after filtering by the silicon powder filter 10 enters the heat exchanger 12 at the inlet of the scrubbing tower 13 to exchange heat with the mixed gas, and then the tail gas after heat exchange enters the scrubbing tower 13 to be sprayed, dusted, and cooled again, and then the material at the top of the scrubbing tower 13 is transported to the air cooling tower 16 to be cooled, and then enters the cooling system for further cooling.

[0108] The cold hydrogenation production system and the cold hydrogenation production process in this embodiment fully utilize heat through heat exchange, reduce the load of the heater of the material pretreatment system, reduce the power consumption of the cold hydrogenation workshop from 0.34 degree / kg.TCS to 0.2 degree / kg.TCS (TCS is the abbreviation of trichlorosilane), fully utilize the surplus heat in the system, optimize the process parameters, reduce the consumption of system power, and greatly reduce the production cost of polysilicon.

[0109] It can be understood that the above embodiments are only exemplary embodiments for illustrating the principles of the present application, and the present application is not limited thereto. Various modifications and improvements can be made by those skilled in the art without departing from the spirit and essence of the present application, and these modifications and improvements are also considered to be within the protection scope of the present application.

Claims

1. A cold hydrogenation production system, characterized in that, include: An electric heater is used to heat the hydrogen and silicon tetrachloride gas introduced into the reactor. The reactor is connected to an electric heater, where hydrogen and silicon tetrachloride react to produce trichlorosilane and hydrogen chloride. The tail gas heat exchanger is connected to the reactor. The tail gas flowing out of the reactor exchanges heat with the hydrogen and silicon tetrachloride flowing out of the heat exchanger. The tail gas heat exchanger is also connected to the electric heater. The hydrogen and silicon tetrachloride that have exchanged heat in the tail gas heat exchanger flow into the electric heater. The silicon powder filter is connected to the exhaust gas heat exchanger. The exhaust gas flowing out of the exhaust gas heat exchanger is passed into the silicon powder filter to filter and remove silicon powder. The silicon powder collection tank is connected to the silicon powder filter. The silicon powder collection tank is used to collect the silicon powder filtered out by the silicon powder filter. The silicon powder collection tank is also connected to the reactor. Hydrogen and silicon powder exchange heat in the silicon powder collection tank. The heat-exchanged hydrogen flows into the reactor to purge the material in the reactor. A hydrogen preheater is connected to a silicon powder collection tank. The hydrogen preheater is used to preheat hydrogen. The heat exchanger is connected to the exhaust gas heat exchanger and also to the silicon powder filter. The hydrogen and silicon tetrachloride flowing into the heat exchanger from the vaporizer exchange heat with the gas flowing into the heat exchanger from the silicon powder filter. The vaporizer, connected to the heat exchanger, is used to vaporize hydrogen and silicon tetrachloride.

2. The cold hydrogenation production system according to claim 1, characterized in that, The exhaust gas heat exchanger includes: The tail gas primary heat exchanger is connected to the reactor. The tail gas flowing out of the reactor exchanges heat with the hydrogen and silicon tetrachloride flowing out of the tail gas secondary heat exchanger in the tail gas primary heat exchanger. The exhaust gas secondary heat exchanger is connected to the exhaust gas primary heat exchanger. The exhaust gas flowing out of the primary heat exchanger exchanges heat with the hydrogen and silicon tetrachloride flowing out of the heat exchanger in the exhaust gas secondary heat exchanger.

3. The cold hydrogenation production system according to claim 1, characterized in that, Also includes: The washing tower, connected to the heat exchanger, is used to wash the material that has flowed into the heat exchanger from the silicon powder filter and undergone heat exchange, removing silicon powder by using trichlorosilane.

4. The cold hydrogenation production system according to claim 3, characterized in that, Also includes: A static mixer, connected to the vaporizer, is used to mix the incoming hydrogen gas with silicon tetrachloride preheated by the silicon tetrachloride preheater, and the mixture flows into the vaporizer. The silicon tetrachloride preheater is connected to the static mixer and is used to preheat silicon tetrachloride.

5. The cold hydrogenation production system according to claim 4, characterized in that, Also includes: The multi-effect heat exchanger is connected to the scrubbing tower and also to the silicon tetrachloride preheater for introducing silicon tetrachloride into the preheater. The multi-effect heat exchanger is also connected to the static mixer for introducing hydrogen into the static mixer. The multi-effect heat exchanger is used to introduce hydrogen and silicon tetrachloride separately, and the exhaust gas from the scrubbing tower exchanges heat with the hydrogen and silicon tetrachloride introduced into the multi-effect heat exchanger.

6. The cold hydrogenation production system according to claim 1, characterized in that, Also includes: The silicon powder storage tank is connected to the silicon powder collection tank and also to the reactor. The silicon powder storage tank is used to collect silicon powder flowing into the silicon powder storage tank and the reactor.

7. A cold hydrogenation production process used in the cold hydrogenation production system according to any one of claims 1 to 6, characterized in that, Includes the following steps: Hydrogen and silicon tetrachloride are introduced into the vaporizer for vaporization; Hydrogen and silicon tetrachloride flowing from the vaporizer into the heat exchanger exchange heat with the gas flowing from the silicon powder filter into the heat exchanger. The exhaust gas flowing out of the reactor exchanges heat with the hydrogen and silicon tetrachloride flowing out of the heat exchanger in the exhaust gas heat exchanger. After the hydrogen and silicon tetrachloride have exchanged heat in the exhaust gas heat exchanger, they flow into the electric heater. The exhaust gas flowing out of the exhaust gas heat exchanger is passed into the silicon powder filter to remove silicon powder. Hydrogen and silicon tetrachloride introduced into the reactor are heated by an electric heater; Hydrogen gas heated by an electric heater and silicon tetrachloride are introduced into the reactor to react and produce trichlorosilane and hydrogen chloride.

8. The cold hydrogenation production process used in the cold hydrogenation production system according to claim 7, characterized in that, Using the cold hydrogenation production system of claim 2, the method further includes the following steps: The tail gas flowing out of the reactor exchanges heat with hydrogen and silicon tetrachloride flowing out of the tail gas secondary heat exchanger in the tail gas primary heat exchanger. The temperature of the hydrogen and silicon tetrachloride after heat exchange is 300-350℃. The exhaust gas flowing out of the primary exhaust gas heat exchanger exchanges heat with the hydrogen and silicon tetrachloride flowing out of the heat exchanger in the secondary exhaust gas heat exchanger. The temperature of the hydrogen and silicon tetrachloride after the heat exchange is 420-450℃.

9. The cold hydrogenation production process used in the cold hydrogenation production system according to claim 7, characterized in that, Using the cold hydrogenation production system of claim 5, the method further includes the following steps: After heat exchange in the multi-effect heat exchanger, the temperature of the hydrogen and silicon tetrachloride is 120-150℃. After being preheated by the silicon tetrachloride preheater, the temperature of the preheated silicon tetrachloride is 170-180℃.

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