Jacket type silicon tetrachloride hydrogenation reactor with pressure self-adaptive function
By installing jackets and cooling dust removal sections outside the hydrogenation reactor, the pressure inside and outside the hydrogenation reactor is consistent, the problems of large stress in the shell and high equipment cost of the hydrogenation reactor are solved, and the conversion rate and production efficiency of trichlorosilicon are improved.
Patent Information
- Application Number
- CN202420721752.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-09
- Publication Date
- 2024-12-27
- Estimated Expiration
- 2034-04-09
AI Technical Summary
In the existing cold hydrogenation process, the hydrogenation reactor shell bears a large stress, high equipment cost, and low conversion rate, with a one-way conversion rate of only below 25%.
Design a jacketed silicon tetrachloride hydrogenation reactor with pressure adaptability. By installing an outer jacket on the outside of the hydrogenation reactor and setting a cooling and dust removal section, the mixed gas is refluxed to the reactor after a small flow rate of reaction. Inside, keep the internal and external pressures of the hydrogenation reactor consistent, and reduce the stress on the housing material of the hydrogenation reactor.
It effectively reduces the stress of the hydrogenated reactor shell material, reduces equipment cost investment, and improves the conversion rate of trichlorosilicon, achieving low-cost and efficient production.
Smart Images
Figure CN222240206U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of polysilicon production, and in particular to a device which, in the process of preparing trichlorosilane, extracts a small flow of post-reaction mixed gas from a main pipeline, returns it to the annular cavity of a hydrogenation reactor after passing through a cooling and dust removal section, keeps the pressure of the hydrogenation reactor consistent with that in the annular cavity, and plays a role in reducing the stress on the shell of the hydrogenation reactor. Background Art
[0002] Polysilicon is a key basic raw material for the electronic information industry and the photovoltaic industry. With the rapid development of the solar photovoltaic industry, the demand for polysilicon continues to increase. In recent years, my country has fully utilized its own technological foundation and industrial supporting advantages in the photovoltaic industry, and has achieved rapid development under the dual effects of industrial policy guidance and market demand. At present, the production process of polysilicon mainly adopts the modified Siemens method and the silane cracking method. The modified Siemens method produces polysilicon by reducing trichlorosilane; while the silane cracking method is that trichlorosilane first undergoes a disproportionation reaction to generate silane gas, and the silane gas is then cracked to produce polysilicon. Both of these production processes require the use of trichlorosilane as a production raw material. It can be seen that the preparation of trichlorosilane has become a necessary production process in the polysilicon industry.
[0003] There are two major processes for preparing trichlorosilane using silicon tetrachloride: the anti-disproportionation method and the hydrogenation method. The hydrogenation technology includes thermal hydrogenation technology, low-temperature catalytic hydrogenation method, cold hydrogenation method, chlorination method and plasma hydrogenation method. The cold hydrogenation method uses silicon powder, hydrogen and silicon tetrachloride as raw materials, uses copper-based, nickel-based or iron-based catalysts, and conducts gas-solid phase reaction in a fluidized bed reactor. The mixed gas coming out of the hydrogenation reactor is dedusted and filtered by a dust collector to remove the entrained catalyst and silicon powder. Compared with other technologies, the cold hydrogenation process has the significant advantages of low reaction temperature and low energy consumption, but it also has certain defects, such as the existing low single-pass conversion rate, which is only below 25%. In response to the problem of low conversion rate, patent CN10850920 discloses a production process and system for preparing trichlorosilane. First, the pressure, temperature and hydrogen flow rate in the cold hydrogenation reactor are controlled to increase the yield of trichlorosilane, and then the pressure, temperature and hydrogen chloride flow rate in the chlorination reactor are controlled to increase the conversion rate of trichlorosilane. In addition, the pressure conditions of the existing cold hydrogenation process are mostly 2.5-3.0MPa. The entire reaction needs to be carried out under high pressure, and the stress on the shell of the hydrogenation reactor is very large. In addition, the separated large-particle silicon powder will seriously wear the pipeline during the process of returning to the hydrogenation reactor, resulting in high equipment requirements and high equipment cost investment in the existing technology. If the pressure inside and outside the hydrogenation reactor can be kept consistent, the pressure on the shell of the hydrogenation reactor can be reduced, low-cost materials can be used, and equipment cost investment can be reduced. Utility Model Content
[0004] In view of the above-mentioned defects of the prior art, the utility model proposes a jacketed silicon tetrachloride hydrogenation reactor with a pressure self-adaptive function. The reactor in the existing cold hydrogenation process is composed of only one layer of metal shell, and the material is mostly N8810. On the basis of the existing device, the utility model installs an outer jacket on the outside of the hydrogenation reactor to form an annular cavity with the shell of the hydrogenation reactor; and an additional cooling and dust removal section is provided. Before starting, the annular cavity is pressurized to keep the pressure of the hydrogenation reactor consistent with that in the annular cavity. After starting, when the pressure in the hydrogenation reactor changes, a small flow of post-reaction mixed gas is extracted from the main pipeline, and after passing through the cooling and dust removal device to remove silicon powder particles and chlorosilane gas, it returns to the annular cavity of the hydrogenation reactor, so as to maintain the pressure inside and outside the hydrogenation reactor consistent, and reduce the stress on the shell material of the hydrogenation reactor. Therefore, the outer jacket of the hydrogenation reactor can be made of low-cost materials, which effectively solves the problem of large equipment cost investment.
[0005] The reactions involved in the present utility model are:
[0006] 3SiCl4+2H2+Si→4SiHCl3
[0007] SiCl4+2H2+Si→2SiH2Cl2
[0008] 3HCl+Si→SiHCl3+H2
[0009] The technical solution of the utility model is as follows:
[0010] A jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function; an outer jacket is installed outside the hydrogenation reactor to form an annular cavity with the shell of the hydrogenation reactor, and the cavity is connected with a cooling and dust removal section system to form a self-circulation structure.
[0011] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function; the cooling and dust removal section is provided with a small flow rate post-reaction mixed gas extraction pipeline, which is sequentially connected to an air cooler, a heat exchanger, a gas-liquid separator, an activated carbon adsorption column, and finally connected to the bottom of the annular cavity of the hydrogenation reactor to form a self-circulating structure; the cooling and dust removal section is arranged at the top of the hydrogenation reactor, or between the high-temperature primary heat exchanger and the high-temperature secondary heat exchanger, or between the high-temperature secondary heat exchanger and the high-temperature tertiary heat exchanger, or between the high-temperature tertiary heat exchanger and the silicon powder filter.
[0012] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function; the top of the hydrogenation reactor cylinder is provided with an upper head and a lower head; the lower part of the hydrogenation reactor cylinder is provided with a silicon powder feed port; the upper head of the hydrogenation reactor is provided with a reaction gas outlet, and the lower head is provided with a hydrogen and silicon tetrachloride mixed gas inlet and a slag discharge port; an annular cavity is formed between the outer jacket of the hydrogenation reactor and the shell of the hydrogenation reactor; and a pressure measuring port and a temperature measuring port are provided at the lower part of the jacket.
[0013] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function has a bursting disc arranged between the top of the hydrogenation reactor and the air cooler.
[0014] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function; one or more activated carbon adsorption columns are connected in parallel.
[0015] The specific instructions are as follows:
[0016] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function proposed in the utility model is improved on the basis of the existing cold hydrogenation process device. The existing cold hydrogenation process device includes a hydrogenation reactor (1), an electric heater (2), a high-temperature primary heat exchanger (3), a high-temperature secondary heat exchanger (4), a high-temperature tertiary heat exchanger (5), a high-temperature quaternary heat exchanger (7), and a silicon powder filter (6). On this basis, the present device installs an outer jacket (13) on the outside of the hydrogenation reactor, and additionally sets a cooling and dust removal section, including an air cooler (8), a heat exchanger (9), a gas-liquid separator (10), and an activated carbon adsorption column (11).
[0017] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function is characterized in that the silicon tetrachloride and hydrogen delivery pipelines are sequentially connected to the high-temperature fourth-stage heat exchanger (7), the high-temperature third-stage heat exchanger (5), the high-temperature second-stage heat exchanger (4), the high-temperature first-stage heat exchanger (3) and the electric heater (2), and the outlet of the electric heater (2) is connected to the bottom inlet of the hydrogenation reactor (1). A mixed gas extraction pipeline is arranged on the top of the hydrogenation reactor (1) and sequentially connected to the high-temperature first-stage heat exchanger (3), the high-temperature second-stage heat exchanger (4), the high-temperature third-stage heat exchanger (5), the silicon powder filter (6) and the high-temperature fourth-stage filter (7), and finally connected to the downstream device. The device is additionally provided with a cooling and dust removal section, and a small-flow post-reaction mixed gas extraction pipeline is arranged in the cooling and dust removal section, which is sequentially connected to an air cooler (8), a heat exchanger (9), a gas-liquid separator (10), an activated carbon adsorption column (11), and finally connected to the bottom of the annular cavity of the hydrogenation reactor to form a self-circulation structure; the cooling and dust removal section can be arranged at the top of the hydrogenation reactor, or between the high-temperature primary heat exchanger and the high-temperature secondary heat exchanger, or between the high-temperature secondary heat exchanger and the high-temperature tertiary heat exchanger, or between the high-temperature tertiary heat exchanger and the silicon powder filter.
[0018] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function is characterized in that the structure of the hydrogenation reactor and its outer jacket is as follows: Figure 3As shown. The top of the hydrogenation reactor cylinder is provided with an upper head and a lower head; the lower part of the hydrogenation reactor cylinder is provided with a silicon powder feed port (15); the upper head of the hydrogenation reactor is provided with a reaction gas outlet (14), and the lower head is provided with a hydrogen and silicon tetrachloride mixed gas inlet (16) and a slag discharge port (17). An annular cavity is formed between the outer jacket (13) of the hydrogenation reactor and the hydrogenation reactor shell; a pressure measuring port (18) and a temperature measuring port (19) are provided at the lower part of the jacket, which can display the pressure and temperature in the annular cavity. The pressure difference between the hydrogenation reactor and the annular cavity is always maintained at -0.1 to 0.5 MPa, which effectively reduces the stress on the shell material of the hydrogenation reactor and improves adaptability. The material of the outer jacket is low-cost carbon steel, avoiding the currently most commonly used N8810 material, which greatly saves material costs.
[0019] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function has a main pipeline diameter of 500 mm, and a small flow mixed gas extraction pipeline is set between the high-temperature three-stage heat exchanger and the silicon powder filter, and the diameter of the extraction pipeline is set to 100 mm. When the pressure in the hydrogenation reactor changes, a small flow of post-reaction mixed gas is extracted into the annular cavity to replenish the pressure. The flow rate of the extracted mixed gas is very small, almost 0.
[0020] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function has a cooling and dust removal section that removes silicon powder particles and chlorosilane gas in a small flow mixed gas extracted from a main pipeline, prevents silicon powder from entering the annular cavity and causing wear on the inner wall of the annular cavity, and prolongs the service life of the outer jacket.
[0021] In the jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function, the air cooler (8) and the heat exchanger (9) in the cooling and dust removal section are used to cool down and condense the chlorosilane gas. The temperature of the small flow mixed gas is reduced to 100° C. through the air cooler (8), and then the temperature is reduced to 0° C. to -50° C. through the heat exchanger (9). Since the jacket of the hydrogenation reactor is made of low-cost materials, the low temperature can extend the service life of the outer jacket of the hydrogenation reactor.
[0022] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function, the gas-liquid separator (10) in the cooling and dust removal section can maintain the temperature of the mixed material at 0°C to -50°C and separate the chlorosilane liquid and gas. The chlorosilane liquid is extracted from the bottom, and the remaining gas enters the activated carbon adsorption column along the pipeline.
[0023] In the jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function, the function of the activated carbon adsorption column (11) in the cooling and dust removal section is to adsorb the chlorosilane gas that is not completely condensed to prevent the chlorosilane gas from entering the annular cavity. A plurality of activated carbon adsorption columns are connected in parallel, and when one adsorption column reaches saturation, other adsorption columns are used by adjusting valves to achieve parallel regeneration.
[0024] In the jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function, silicon tetrachloride and hydrogen are mixed and vaporized and heated by a vaporizer and a superheater to a temperature of 170-190°C and a pressure of 3.3-3.5 MPa. The vaporized and heated mixed gas is sent to a multi-stage heat exchanger for heat exchange and temperature increase. The mixed gas is heated to 250-260°C after passing through a high-temperature four-stage heat exchanger (7), 320-330°C after passing through a high-temperature three-stage heat exchanger (5), 400-410°C after passing through a high-temperature two-stage heat exchanger (4), 520-530°C after passing through a high-temperature one-stage heat exchanger (3), and 560-570°C after passing through an electric heater (2). Finally, the heated mixed material is sent to the hydrogenation reactor (1) through a hydrogen and silicon tetrachloride mixed gas inlet (16). Silicon powder enters the hydrogenation reactor through the silicon powder feed port (15) and reacts with high-temperature hydrogen and silicon tetrachloride to produce trichlorosilane. The operating pressure of the hydrogenation reactor (1) is 2.5-3.0 MPa, and the reaction temperature is 530-560°C. A mixed gas of trichlorosilane, unreacted silicon tetrachloride and hydrogen is extracted from the top of the hydrogenation reactor at a temperature of 530-560°C and a pressure of 2.5-3.0 MPa. The extracted mixed gas is sent to a multi-stage heat exchanger for heat exchange and cooling. The temperature of the mixed gas drops to 420-430°C after passing through the high-temperature primary heat exchanger (3), drops to 340-350°C after passing through the high-temperature secondary heat exchanger (4), drops to 270-280°C after passing through the high-temperature tertiary heat exchanger (5), drops to 190-210°C after passing through the high-temperature quaternary heat exchanger (7), and finally the mixed gas is sent to the downstream device. In the cooling and dust removal section, before starting, the annular cavity is pressurized to keep the pressure in the hydrogenation reactor consistent with that in the annular cavity, and hydrogen is used as the pressurizing gas; after starting, when the pressure in the hydrogenation reactor changes, a small flow of the post-reaction mixed gas is extracted from the main pipeline and enters the air cooler (8) to cool to about 100°C, and then passes through the heat exchanger (9) to cool and condense to 0-50°C before entering the gas-liquid separator (10), in which the chlorosilane liquid is separated at the bottom, and the remaining gas enters the activated carbon adsorption column (11), wherein the chlorosilane gas that is not completely condensed is adsorbed by the adsorption column, and the remaining hydrogen returns to the annular cavity of the hydrogenation reactor to replenish the pressure, and the pressure of the annular cavity changes with the change of the pressure in the hydrogenation reactor, and the pressure in the hydrogenation reactor and the pressure in the annular cavity are always consistent; when the pressure in the hydrogenation reactor and the pressure in the annular cavity reach equality, the mixed gas is no longer extracted, and the pressure self-adaptation function is realized.
[0025] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function is characterized in that a bursting disc (12) is arranged between the top of the hydrogenation reactor and the air cooler (8), and no gas flows through the bursting disc (12) under normal working conditions; when the cooling and dust removal section system is blocked, the small flow of mixed gas cannot be produced, and the pressure difference between the hydrogenation reactor and the annular cavity increases; when the pressure difference exceeds the bursting pressure of the bursting disc, the bursting disc is punctured, so that the pressure in the hydrogenation reactor and the annular cavity is restored to be consistent.
[0026] The utility model has the following advantages:
[0027] [1] Compared with the traditional reactor, the hydrogenation reactor of the utility model has an additional outer jacket on the outside, and the pressure in the hydrogenation reactor and the annular cavity are always equal through its own circulation structure, thus realizing the function of pressure self-adaptation.
[0028] [2] The outer jacket of the hydrogenation reactor is made of low-cost carbon steel, avoiding the use of the most commonly used N8810 material, which greatly saves material costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 The flow chart of the device for extracting mixed gas from between the high-temperature three-stage heat exchanger and the filter.
[0030] Figure 2 The figure is a flow chart of the device for extracting mixed gas from the top of the hydrogenation reactor.
[0031] Figure 3 It is a schematic diagram of the structure of the hydrogenation reactor and the outer jacket.
[0032] Among them: 1-hydrogenation reactor; 2-electric heater; 3-high-temperature primary heat exchanger; 4-high-temperature secondary heat exchanger; 5-high-temperature tertiary heat exchanger; 6-silicon powder filter; 7-high-temperature fourth-stage filter; 8-air cooler; 9-heat exchanger; 10-gas-liquid separator; 11-activated carbon adsorption column; 12-bursting disc; 13-hydrogenation reactor jacket; 14-reaction gas outlet; 15-silicon powder inlet and silicon powder return port; 16-hydrogen and silicon tetrachloride mixed gas inlet; 17-slag discharge port; 18-pressure measuring port; 19-temperature measuring port. DETAILED DESCRIPTION
[0033] In order to illustrate the utility model in more detail, further explanation is given below in conjunction with the drawings and embodiments. Detailed examples and specific operating processes are given below. Obviously, the embodiments described below are only some embodiments of the utility model and do not include all embodiments. The protection scope of the utility model is not limited to the following embodiments. Other embodiments obtained by other technicians in this field without making creative changes are all within the protection scope of the utility model.
[0034] Example 1:
[0035] like Figure 1 As shown, the cooling and dust removal section is arranged between the high-temperature three-stage heat exchanger (5) and the silicon powder filter (6). The silicon tetrachloride and hydrogen delivery pipelines are connected to the high-temperature four-stage heat exchanger (7), the high-temperature three-stage heat exchanger (5), the high-temperature two-stage heat exchanger (4), the high-temperature one-stage heat exchanger (3) and the electric heater (2) in sequence, and the outlet of the electric heater (2) is connected to the bottom inlet of the hydrogenation reactor (1). A mixed gas extraction pipeline is arranged on the top of the hydrogenation reactor (1) and is connected to the high-temperature one-stage heat exchanger (3), the high-temperature two-stage heat exchanger (4), the high-temperature three-stage heat exchanger (5), the silicon powder filter (6) and the high-temperature four-stage filter (7) in sequence, and finally connected to the downstream device. The device is additionally provided with a cooling and dust removal section, and the cooling and dust removal section is provided with a small flow of post-reaction mixed gas extraction pipeline between the high-temperature three-stage heat exchanger (5) and the silicon powder filter (6), and is connected to the air cooler (8), the heat exchanger (9), the gas-liquid separator (10), the activated carbon adsorption column (11) in sequence, and finally connected to the bottom of the annular cavity of the hydrogenation reactor.
[0036] After the silicon tetrachloride and hydrogen are mixed, they are successively vaporized and heated in a vaporizer and a superheater at a temperature of 180°C and a pressure of 3.4 MPa. Subsequently, the mixture is passed into a high-temperature four-stage heat exchanger (7) for the first heat exchange, and the temperature is raised to 252°C. Then, the mixture is passed into a high-temperature three-stage heat exchanger (5) for the second heat exchange, and the temperature reaches 327°C. Then, the mixture is passed into a high-temperature two-stage heat exchanger (4) for the third heat exchange, and the temperature reaches 401°C. Then, the mixture is passed into a high-temperature one-stage heat exchanger (3) for the fourth heat exchange, and the temperature reaches 522°C. Finally, the mixture is passed into an electric heater (2) for heat exchange, and the temperature is raised to 565°C. The heated mixed material is fed into the bottom of a hydrogenation reactor (1), and the high-temperature hydrogen, silicon tetrachloride and silicon powder react in the hydrogenation reactor (1) to generate trichlorosilane. The operating pressure of the hydrogenation reactor in this example is 3.0 MPa, and the reaction temperature is 550°C. Subsequently, a mixed gas of trichlorosilane, unreacted silicon tetrachloride and hydrogen is extracted from the top of the hydrogenation reactor at a temperature of 540°C and a pressure of 3.0 MPa. The mixed gas is then passed into a high-temperature primary heat exchanger (3) for the first heat exchange to reduce the temperature to 421°C, then passed into a high-temperature secondary heat exchanger (4) for the second heat exchange to reduce the temperature to 347°C, then passed into a high-temperature tertiary heat exchanger (5) for the third heat exchange to reduce the temperature to 272°C, passed through a silicon powder filter (6) to remove silicon powder in the mixed gas to prevent silicon powder particles from affecting subsequent processes, then passed into a high-temperature tertiary heat exchanger (7) for the fourth heat exchange to reduce the temperature to 200°C, and finally flows into a downstream device.
[0037] In the cooling and dust removal section, the annular cavity is pressurized to 3.0MPa before starting, and hydrogen is used as the pressurized gas; after starting, when the pressure in the hydrogenation reactor changes, a pressure difference is generated between the hydrogenation reactor and the gas in the annular cavity, and a small flow of the reaction mixed gas is extracted from between the high-temperature third-stage heat exchanger (5) and the high-temperature fourth-stage heat exchanger (7), and enters the air cooler (8) and the heat exchanger (9) in turn. The cold source of the air cooler (8) is circulating water, and the mixed gas and the cold source fully transfer heat and exchange heat on both sides of the heat exchange structure. The circulating water temperature rises from 30°C to 40°C, and the mixed gas temperature drops to 50°C. The cold source of the heat exchanger (9) is Freon, which reduces the temperature of the mixed gas to -35°C. The condensed chlorosilane liquid enters the buffer tank and finally enters the chlorosilane product tank. The chlorosilane gas that is not completely condensed enters the activated carbon adsorption column (11) and is adsorbed, and the remaining hydrogen returns to the annular cavity of the hydrogenation reactor to replenish the pressure; when the pressure in the hydrogenation reactor and the annular cavity are equal, the small flow mixed gas is no longer produced. At this time, the pressure difference between the hydrogenation reactor and the annular cavity is 0, which effectively reduces the stress on the shell material of the hydrogenation reactor.
[0038] A bursting disc is installed between the top of the hydrogenation reactor and the air cooler, and the bursting pressure is 0.2MPa. Under normal working conditions, there is no gas flow at the bursting disc; when the cooling and dust removal system is blocked, the small flow of mixed gas cannot be produced, and the pressure difference between the hydrogenation reactor and the annular cavity increases. When the pressure difference exceeds the bursting pressure of the bursting disc, the bursting disc is punctured, and the pressure in the hydrogenation reactor and the annular cavity is restored to be consistent.
[0039] In this exemplary implementation, the shell of the hydrogenation reactor is made of a composite material of N8810 and 31608, and the material of the outer jacket is low-cost carbon steel, which greatly saves material costs.
[0040] In this exemplary implementation, the gas returning to the annular cavity contains less silicon powder, and the wear on the hydrogenation reactor shell and the inner wall of the annular cavity is lower; in addition, the temperature of the gas returning to the annular cavity is lower.
[0041] Example 2:
[0042] like Figure 2As shown, unlike Example 1, the cooling and dust removal section of this example is arranged at the top of the hydrogenation reactor (1). The silicon tetrachloride and hydrogen delivery pipelines are connected to the high-temperature four-stage heat exchanger (7), the high-temperature three-stage heat exchanger (5), the high-temperature two-stage heat exchanger (4), the high-temperature one-stage heat exchanger (3) and the electric heater (2) in sequence, and the outlet of the electric heater (2) is connected to the bottom inlet of the hydrogenation reactor (1). A mixed gas extraction pipeline is arranged at the top of the hydrogenation reactor (1), which is connected to the high-temperature one-stage heat exchanger (3), the high-temperature two-stage heat exchanger (4), the high-temperature three-stage heat exchanger (5), the silicon powder filter (6) and the high-temperature four-stage filter (7) in sequence, and finally connected to the downstream device. The device is additionally provided with a cooling and dust removal section, and the cooling and dust removal section is provided with a small flow rate of the reaction mixed gas extraction pipeline at the top of the hydrogenation reactor (1), which is connected to the air cooler (8), the heat exchanger (9), the gas-liquid separator (10), the activated carbon adsorption column (11) in sequence, and finally connected to the bottom of the annular cavity of the hydrogenation reactor to form a self-circulation structure.
[0043] After the silicon tetrachloride and hydrogen are mixed, they are successively vaporized and heated in a vaporizer and a superheater at a temperature of 180°C and a pressure of 3.4 MPa. Subsequently, the mixture is passed into a high-temperature four-stage heat exchanger (7) for the first heat exchange, and the temperature is raised to 252°C. Then, the mixture is passed into a high-temperature three-stage heat exchanger (5) for the second heat exchange, and the temperature reaches 327°C. Then, the mixture is passed into a high-temperature two-stage heat exchanger (4) for the third heat exchange, and the temperature reaches 401°C. Then, the mixture is passed into a high-temperature one-stage heat exchanger (3) for the fourth heat exchange, and the temperature reaches 522°C. Finally, the mixture is passed into an electric heater (2) for heat exchange, and the temperature is raised to 565°C. The heated mixed material is fed into the bottom of a hydrogenation reactor (1), and the high-temperature hydrogen, silicon tetrachloride and silicon powder react in the hydrogenation reactor (1) to generate trichlorosilane. The operating pressure of the hydrogenation reactor in this example is 3.0 MPa, and the reaction temperature is 550°C. Subsequently, a mixed gas of trichlorosilane, unreacted silicon tetrachloride and hydrogen is extracted from the top of the hydrogenation reactor at a temperature of 540°C and a pressure of 3.0 MPa. The mixed gas is then passed into a high-temperature primary heat exchanger (3) for the first heat exchange to reduce the temperature to 421°C, then passed into a high-temperature secondary heat exchanger (4) for the second heat exchange to reduce the temperature to 347°C, then passed into a high-temperature tertiary heat exchanger (5) for the third heat exchange to reduce the temperature to 272°C, passed through a silicon powder filter (6) to remove silicon powder in the mixed gas to prevent silicon powder particles from affecting subsequent processes, then passed into a high-temperature tertiary heat exchanger (7) for the fourth heat exchange to reduce the temperature to 200°C, and finally flows into a downstream device.
[0044] In the cooling and dust removal section, the annular cavity is pressurized to 3.0 MPa before starting, and hydrogen is used as the pressurizing gas; after starting, when the pressure in the hydrogenation reactor increases, the pressure in the hydrogenation reactor is greater than the pressure in the annular cavity, resulting in a pressure difference. Under the action of the pressure difference, a small flow of mixed gas is produced from the top of the hydrogenation reactor along the production pipeline at the top of the hydrogenation reactor, and first enters the shell-and-tube air cooler (8) to cool to 100°C. The mixed gas coming out of the air cooler (8) enters the heat exchanger (9) to cool and condense to -35°C, and then enters the gas-liquid separator (10). The gas-liquid separator (10) keeps the temperature of the mixed gas at -35°C. The chlorosilane gas in the mixed gas is condensed into liquid and separated and removed at the bottom. The remaining gas enters the activated carbon adsorption column (11), in which the chlorosilane gas that is not completely condensed is adsorbed, and the remaining hydrogen returns to the annular cavity of the hydrogenation reactor to replenish the pressure; when the pressure in the hydrogenation reactor and the annular cavity reaches the same level, the mixed gas is no longer produced. At this time, the pressure difference between the hydrogenation reactor and the annular cavity is 0, which effectively reduces the stress on the shell material of the hydrogenation reactor.
[0045] A bursting disc is installed between the top of the hydrogenation reactor and the air cooler, and the bursting pressure of the bursting disc is 0.2MPa. Under normal working conditions, there is no gas flow at the bursting disc; when the cooling and dust removal system is blocked, the small flow of mixed gas cannot be produced, and the pressure difference between the hydrogenation reactor and the annular cavity increases. When the pressure difference exceeds the bursting pressure of the bursting disc, the bursting disc is punctured, and the pressure in the hydrogenation reactor and the annular cavity is restored to be consistent.
[0046] Example 3:
[0047] Different from Example 1, the cooling and dust removal section of this example is arranged after the electric heater (2). The silicon tetrachloride and hydrogen delivery pipelines are connected to the high-temperature four-stage heat exchanger (7), the high-temperature three-stage heat exchanger (5), the high-temperature two-stage heat exchanger (4), the high-temperature one-stage heat exchanger (3) and the electric heater (2) in sequence, and the outlet of the electric heater (2) is connected to the bottom inlet of the hydrogenation reactor (1). A mixed gas extraction pipeline is arranged at the top of the hydrogenation reactor (1), which is connected to the high-temperature one-stage heat exchanger (3), the high-temperature two-stage heat exchanger (4), the high-temperature three-stage heat exchanger (5), the silicon powder filter (6) and the high-temperature four-stage filter (7) in sequence, and finally connected to the downstream device. The device is additionally provided with a cooling and dust removal section, and the cooling and dust removal section is provided with a small flow of post-reaction mixed gas extraction pipeline after the electric heater (2), which is connected to the air cooler (8), the heat exchanger (9), the gas-liquid separator (10), the activated carbon adsorption column (11) in sequence, and finally connected to the bottom of the annular cavity of the hydrogenation reactor to form a self-circulation structure.
[0048] After the silicon tetrachloride and hydrogen are mixed, they are successively vaporized and heated in a vaporizer and a superheater at a temperature of 180°C and a pressure of 3.4 MPa. Subsequently, the mixture is passed into a high-temperature four-stage heat exchanger (7) for the first heat exchange, and the temperature is raised to 252°C. Then, the mixture is passed into a high-temperature three-stage heat exchanger (5) for the second heat exchange, and the temperature reaches 327°C. Then, the mixture is passed into a high-temperature two-stage heat exchanger (4) for the third heat exchange, and the temperature reaches 401°C. Then, the mixture is passed into a high-temperature one-stage heat exchanger (3) for the fourth heat exchange, and the temperature reaches 522°C. Finally, the mixture is passed into an electric heater (2) for heat exchange, and the temperature is raised to 565°C. The heated mixed material is fed into the bottom of a hydrogenation reactor (1), and the high-temperature hydrogen, silicon tetrachloride and silicon powder react in the hydrogenation reactor (1) to generate trichlorosilane. The operating pressure of the hydrogenation reactor in this example is 3.0 MPa, and the reaction temperature is 550°C. Subsequently, a mixed gas of trichlorosilane, unreacted silicon tetrachloride and hydrogen is extracted from the top of the hydrogenation reactor at a temperature of 540°C and a pressure of 3.0 MPa. The mixed gas is then passed into a high-temperature primary heat exchanger (3) for the first heat exchange to reduce the temperature to 421°C, then passed into a high-temperature secondary heat exchanger (4) for the second heat exchange to reduce the temperature to 347°C, then passed into a high-temperature tertiary heat exchanger (5) for the third heat exchange to reduce the temperature to 272°C, passed through a silicon powder filter (6) to remove silicon powder in the mixed gas to prevent silicon powder particles from affecting subsequent processes, then passed into a high-temperature tertiary heat exchanger (7) for the fourth heat exchange to reduce the temperature to 200°C, and finally flows into a downstream device.
[0049] In the cooling and dust removal section, the annular cavity is pressurized to 3.0 MPa before starting, and hydrogen is used as the pressurized gas; after starting, when the pressure in the hydrogenation reactor changes, a pressure difference is generated between the hydrogenation reactor and the gas in the annular cavity, and a small flow of the reaction mixed gas is extracted from the electric heater (2), first entering the shell and tube air cooler (8) to cool to 100°C, and the mixed gas coming out of the air cooler (8) enters the heat exchanger (9) to cool and condense to -35°C, and then enters the gas-liquid separator (10), the temperature of the gas-liquid separator (10) is maintained at -35°C, the chlorosilane gas in the mixed gas is condensed into liquid and separated at the bottom, and the remaining gas enters the activated carbon adsorption column (11), wherein the chlorosilane gas that is not completely condensed is adsorbed, and the remaining hydrogen returns to the annular cavity of the hydrogenation reactor to replenish the pressure; when the pressure in the hydrogenation reactor and the annular cavity reaches the same, the small flow of mixed gas is no longer extracted. At this time, the pressure difference between the hydrogenation reactor and the annular cavity is 0, which effectively reduces the stress on the shell material of the hydrogenation reactor. The outer jacket is made of carbon steel, which greatly saves material costs.
[0050] A bursting disc is installed between the top of the hydrogenation reactor and the air cooler, and the bursting pressure of the bursting disc is 0.2MPa. Under normal working conditions, there is no gas flow at the bursting disc; when the cooling and dust removal system is blocked, the small flow of mixed gas cannot be produced, and the pressure difference between the hydrogenation reactor and the annular cavity increases. When the pressure difference exceeds the bursting pressure of the bursting disc, the bursting disc is punctured, so that the pressure in the hydrogenation reactor and the annular cavity is restored to the same level.
[0051] In this exemplary embodiment, the gas returning to the annulus contains less trichlorosilane and silicon powder.
[0052] The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function proposed by the utility model has been described by embodiments. The technical scheme disclosed and proposed by the utility model can be realized by relevant technical personnel by referring to the content of this article and appropriately changing the conditions, routes and other links. Although the method and preparation technology of the utility model have been described by preferred embodiments, relevant technical personnel can obviously change or re-combine the methods and technical routes described herein without departing from the content, spirit and scope of the utility model to realize the final preparation technology. It is particularly important to point out that all similar replacements and changes are obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the utility model.
Claims
1. A jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function; characterized in that: An outer jacket is installed outside the hydrogenation reactor to form an annular cavity with the shell of the hydrogenation reactor. The cavity is connected with the cooling and dust removal section system to form a self-circulation structure.
2. The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function as claimed in claim 1; characterized in that: The cooling and dust removal section is provided with a small flow rate post-reaction mixed gas extraction pipeline, which is sequentially connected to the air cooler, the heat exchanger, the gas-liquid separator, the activated carbon adsorption column, and finally connected to the bottom of the annular cavity of the hydrogenation reactor to form a self-circulating structure; the cooling and dust removal section is arranged at the top of the hydrogenation reactor, or between the high-temperature primary heat exchanger and the high-temperature secondary heat exchanger, or between the high-temperature secondary heat exchanger and the high-temperature tertiary heat exchanger, or between the high-temperature tertiary heat exchanger and the silicon powder filter.
3. The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function as claimed in claim 1; characterized in that: An upper head and a lower head are arranged on the top of the hydrogenation reactor cylinder; a silicon powder feed port is arranged at the lower part of the hydrogenation reactor cylinder; a reaction gas outlet is arranged on the upper head of the hydrogenation reactor, and a hydrogen and silicon tetrachloride mixed gas inlet and a slag discharge port are arranged on the lower head; an annular cavity is formed between the outer jacket of the hydrogenation reactor and the shell of the hydrogenation reactor; a pressure measuring port and a temperature measuring port are arranged at the lower part of the jacket.
4. The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function as claimed in claim 1; characterized in that: A bursting disc is arranged between the top of the hydrogenation reactor and the air cooler.
5. The jacketed silicon tetrachloride hydrogenation reactor with pressure self-adaptation function as claimed in claim 1; characterized in that: Activated carbon adsorption column One or more activated carbon adsorption columns are connected in parallel.