Reactor for producing granular silicon

Abstract

The utility model provides a reactor for producing granular silicon, which comprises a reactor body and a heating element arranged on the outer surface of the reactor body, a seed crystal feed port is arranged at the top of the reactor body, an auxiliary gas feed port, a feed gas feed port and a granular silicon discharge port are arranged on a bottom plate of the reactor body, and the heating element is arranged on the outer surface of the reactor body. The auxiliary gas feed ports are annularly distributed, and the raw material gas feed port and the granular silicon discharge port are located in a ring defined by the auxiliary gas feed ports. According to the utility model, the auxiliary gas feeding hole is formed in the periphery of the bottom of the reactor main body, so that when auxiliary gas enters the reactor main body through the auxiliary gas feeding hole, an annular gas curtain is formed in the reactor main body, and the effect of isolating the gas curtain can be effectively achieved; therefore, silicon generated by reaction of the raw material gas and silicon formation can be prevented from being deposited on the inner wall of the reactor body from the micro silicon powder.

Description

Technical Field

[0001] The utility model belongs to the technical field of polysilicon preparation, and relates to a production technology for producing granular silicon, in particular to a reactor for producing granular silicon. Background Art

[0002] Polysilicon is one of the main raw materials for solar photovoltaic power generation. The current mainstream polysilicon production technology is the fluidized bed method using silane gas as raw material. The fluidized bed reactor is the main reaction equipment. In the fluidized bed reactor, silane gas is pyrolyzed to generate silicon, which is deposited on the surface of the seed crystal in the fluidized state. The seed crystal continues to grow to form granular silicon.

[0003] US Patent No. 7,029,632 discloses a radiation-heated fluidized bed reactor, which radiates heat to the reaction zone through a heat source outside the inner tube of the reactor. US Patent No. 4,883,687 shows another fluidized bed reactor with external heating, which provides heat to the reaction zone by heat conduction. This external heating method of heat radiation or heat conduction will cause the temperature of the inner wall of the reactor body to be greater than the temperature of the material inside the reactor body, which is easy to cause silicon formed by the thermal decomposition of silane gas to be deposited on the inner wall of the reactor body, hindering the transfer of heat to the inside of the reactor body. Therefore, this heating method usually brings a large energy loss to the system. Especially after the fluidized bed reactor is enlarged, this contradiction is more prominent. The temperature of the inner wall of the reactor body is too high and silicon deposition occurs, but the center temperature of the reactor body cannot reach the decomposition temperature of silane or chlorosilane. This not only affects the production efficiency of the fluidized bed reactor, but also has to be stopped for inspection, cleaning or replacement due to the silicon deposited on the inner wall of the reactor body, resulting in limited production capacity.

[0004] In order to solve the problem of silicon deposition on the inner wall of the reactor body, U.S. Patent No. 4,786,477 discloses a microwave-heated fluidized bed reactor, in which silicon particles are heated by microwaves through a microwave generator located outside the reactor. This method can make the temperature of the inner wall of the reactor lower than the temperature of the silicon particles, thereby avoiding the problem of silicon deposition on the inner wall of the reactor body to a certain extent. However, this fluidized bed reactor requires a specific microwave generator, which is too expensive and is not conducive to practical application.

[0005] Some researchers have designed internally heated fluidized bed reactors, where heating elements are placed inside the reactor body. However, the temperature of the heating elements is generally higher than the gas phase temperature and solid particle temperature inside the reactor body, causing silicon deposition on the heating elements. This ultimately leads to reduced heating efficiency and even the problem of having to stop the reactor for maintenance or replacement of the heating elements, thus affecting the operating cycle of the fluidized bed reactor and directly affecting its production capacity.

[0006] In summary, the existing fluidized bed reactors cannot fundamentally solve the problem of silicon deposition. Silicon deposition not only affects the heat transfer efficiency, but also wears out the internal structure of the reactor body, affecting the efficiency and stable operation cycle of granular silicon production, reducing raw material utilization, and increasing production costs. Utility Model Content

[0007] In order to solve the above problems of the prior art, the utility model provides a reactor for producing granular silicon, which can fundamentally solve the problem of silicon deposition on the inner wall of the reactor body.

[0008] The utility model is realized by the following technical solutions:

[0009] A reactor for producing granular silicon comprises a reactor body and a heating element arranged on the outer surface of the reactor body, wherein a seed crystal feed port is arranged on the top of the reactor body, an auxiliary gas feed port, a raw gas feed port and a granular silicon discharge port are arranged on the bottom plate of the reactor body, the auxiliary gas feed port is distributed in a ring shape, and the raw gas feed port and the granular silicon discharge port are located in a ring surrounded by the auxiliary gas feed port.

[0010] Preferably, the ring formed by the auxiliary gas feed inlets is coaxial with the reactor body, and the distance between the auxiliary gas feed inlets and the inner wall of the reactor body is 20-200 mm.

[0011] Preferably, a plurality of auxiliary gas feed inlets are provided, and the plurality of auxiliary gas feed inlets are distributed in a ring shape.

[0012] Preferably, the bottom plate of the reactor body includes a hollow first frustum and a hollow second frustum, the first frustum is located inside the second frustum, the upper base area of ​​the first frustum is smaller than the lower base area, the upper base area of ​​the second frustum is larger than the lower base area, the lower base of the first frustum is open, the upper base of the second frustum is open, the bottom of the first frustum is connected to the bottom of the second frustum through a platform; the granular silicon discharge port is opened on the platform, the auxiliary gas feed port is opened on the side wall of the second frustum; the raw gas feed port is opened on the first frustum.

[0013] Preferably, the heating element comprises a first heating element and a second heating element, the first heating element is located in the upper section of the reactor body, and the second heating element is located in the middle section of the reactor body.

[0014] Furthermore, the first heating element is an electric heating belt, which is wound around the outer surface of the reactor body; the second heating element includes a plurality of electric heating rods, which are arranged along the circumference of the reactor body.

[0015] Furthermore, the number of the electric heating rods is 60-100.

[0016] Preferably, a heat-insulating layer is provided outside the reactor body, and a furnace hood is provided outside the heat-insulating layer.

[0017] Furthermore, an inert gas inlet is provided on the furnace hood, and the inert gas inlet is used to introduce inert gas into the gap between the furnace hood and the insulation layer.

[0018] Preferably, a filter distributor is provided at the raw gas feed inlet and / or the auxiliary gas feed inlet.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] The utility model arranges an auxiliary gas feed port on the periphery of the bottom of the reactor body, and arranges the raw gas feed port and the granular silicon discharge port in a ring surrounded by the auxiliary gas feed port, so that when the auxiliary gas enters the reactor body through the auxiliary gas feed port, an annular air curtain is formed in the reactor body, which can effectively play the role of air curtain isolation, and the raw gas and seed crystals react in the middle area surrounded by the air curtain, so as to avoid the silicon generated by the raw gas reaction and the silicon forming micro-silicon powder from being deposited on the inner wall of the reactor body, and avoid the problem of low heat conduction efficiency and damage to the reactor body caused by excessive deposition of silicon powder on the inner wall of the reactor body, and the fluidized bed reactor of this design does not require excessive additional costs and can be actually applied.

[0021] Furthermore, the ring formed by the auxiliary gas feed port of the utility model is coaxial with the reactor body, and the distance between the auxiliary gas feed port and the inner wall of the reactor body is 20-200 mm, that is, the auxiliary gas feed port is close to the inner wall of the reactor body, and after the auxiliary gas enters, an air curtain is formed at a position close to the inner wall of the reactor body, which not only plays an isolation role, but also does not affect the effective reaction area in the reactor body.

[0022] Furthermore, the bottom plate of the reactor body of the utility model and the arrangement of the granular silicon outlet and the raw gas feed port make the position of the raw gas feed port higher than that of the granular silicon outlet, thereby preventing the granular silicon from blocking the raw gas inlet; at the same time, the structural design of the frustum allows the granular silicon product and microsilicon powder to slide downward along the inclined surface of the frustum, thereby effectively preventing the accumulation and deposition of granular silicon and microsilicon powder around the raw gas feed port, thereby preventing the granular silicon product from blocking the raw gas feed port.

[0023] Furthermore, the reactor body of the utility model adopts a two-stage heating method of the middle and upper parts, which can increase the reaction time and area of ​​the raw gas and seed crystals, improve the output efficiency of granular silicon products, improve the utilization rate of raw materials and equipment, and significantly reduce operating costs.

[0024] Furthermore, a heat preservation layer is arranged outside the reactor body of the utility model, and a furnace cover is used for protection outside the heat preservation layer.

[0025] Furthermore, the utility model introduces inert gas into the furnace cover, which can not only protect the thermal insulation material, but also prevent the reactor body from leaking and causing safety accidents, thereby improving the operating safety of the equipment.

[0026] Furthermore, the utility model sets a filter distributor at the raw gas feed inlet and / or the auxiliary gas feed inlet, which can not only evenly distribute the gas, but also filter particles and dust to prevent particles and dust from entering the raw gas or auxiliary gas pipelines and clogging equipment and pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is an axial cross-sectional view of a reactor for producing granular silicon in a specific embodiment of the utility model;

[0029] Figure 2 for Figure 1 Cross-section view in AA direction;

[0030] Figure 3 for Figure 1 Cross-sectional view in the BB direction.

[0031] In the figure: 1 is the reactor body, 2 is the seed feed port, 3 is the auxiliary gas feed port, 4 is the raw gas feed port, 5 is the granular silicon discharge port, 6 is the filter distributor, 7 is the exhaust gas outlet, 8 is the first heating element, 9 is the second heating element, 10 is the insulation layer, and 11 is the furnace hood. DETAILED DESCRIPTION

[0032] The following is an explanation of the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.

[0034] It should be noted that the terms "include" and "have" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the utility model. Changes or adjustments in their relative relationships should also be regarded as the scope of the utility model without substantially changing the technical content.

[0035] In addition, it should be noted that the terms "first", "second", etc. of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. The orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention; in addition, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements.

[0036] like Figure 1 As shown, the reactor for producing granular silicon described in the utility model includes a reactor body 1 and a heating element arranged on the outer surface of the reactor body 1, a seed feed port 2 is arranged on the top of the reactor body 1, an auxiliary gas feed port 3, a raw gas feed port 4 and a granular silicon discharge port 5 are arranged on the bottom plate of the reactor body 1, the auxiliary gas feed port 3 is distributed in a ring, and the raw gas feed port 4 and the granular silicon discharge port 5 are located in the ring surrounded by the auxiliary gas feed port 3; when the auxiliary gas enters the reactor body 1 through the auxiliary gas feed port 3, an annular gas curtain is formed in the reactor body 1.

[0037] When the auxiliary gas of the utility model enters the reactor body 1, an annular gas curtain will be formed in the reactor body 1, thereby isolating the raw gas, seed crystals, etc. from the inner wall of the reactor body 1, preventing the silicon in the reactor body 1 from being deposited on the inner wall of the reactor body 1, and avoiding the problem of low heat conduction efficiency and damage to the reactor body 1 caused by excessive deposition of silicon powder on the inner wall of the reactor body 1.

[0038] In some specific embodiments of the present invention, the ring formed by the auxiliary gas feed port 3 is coaxial with the reactor body 1, and preferably the distance between the auxiliary gas feed port 3 and the inner wall of the reactor body 1 is 20-200 mm. That is, the auxiliary gas feed port 3 is close to the inner wall of the reactor body 1, and after the auxiliary gas enters, a gas curtain is formed at a position close to the inner wall of the reactor body 1, which not only plays an isolation role, but also does not affect the effective reaction area in the reactor body 1.

[0039] In some specific embodiments of the present invention, the auxiliary gas feed inlet 3 is provided in plurality, and the plurality of auxiliary gas feed inlets 3 are distributed in an annular shape, that is, the centers of the plurality of auxiliary gas feed inlets 3 are located on the same ring. The auxiliary gas feed inlet 3 is preferably circular, and the centers of the plurality of auxiliary gas feed inlets 3 are located on the same ring, such as Figure 3 shown.

[0040] In some specific embodiments of the utility model, the bottom plate of the reactor body 1 includes a hollow first frustum and a hollow second frustum, the first frustum is located inside the second frustum, the upper bottom area of ​​the first frustum is smaller than the lower bottom area, the upper bottom area of ​​the second frustum is larger than the lower bottom area, the lower bottom of the first frustum is open, and the bottom of the first frustum is connected to the bottom of the second frustum through a platform, and the upper bottom of the second frustum is open. The granular silicon discharge port 5 is opened on the platform, and the auxiliary gas feed port 3 is opened on the side wall of the second frustum. The raw gas feed port 4 is opened on the upper bottom surface and the side wall of the first frustum, and the multiple raw gas feed ports 4 on the side wall of the first frustum are preferably located on the same cross section and are evenly distributed. Therefore, the position of the raw gas feed port 4 is higher than the position of the granular silicon discharge port 5, which can prevent the granular silicon from blocking the raw gas inlet.

[0041] In the present invention, preferably 4-10 granular silicon discharge ports 5 are evenly arranged on the platform.

[0042] In some specific embodiments of the utility model, a filter distributor 6 can be selectively set at the raw gas feed port 4 and the auxiliary gas feed port 3, such as a static gas distributor, a dynamic pipeline gas distributor, or a metal porous micro-distributor, which can not only distribute the gas, but also filter particles and dust, and can isolate 0.02 micron-1 mm particles and fine powder.

[0043] In some specific embodiments of the present invention, the reactor body 1 is provided with an exhaust gas outlet 7 at the top, and a filter distributor 6 can also be provided at the exhaust gas outlet 7 to separate the microsilicon powder from the exhaust gas. The reactor body 1 can also be provided with an emergency safety discharge port.

[0044] In some specific embodiments of the utility model, the heating element includes a first heating element 8 and a second heating element 9. The first heating element 8 is located in the upper section of the reactor body 1, and the second heating element 9 is located in the middle section of the reactor body 1. The first heating element 8 is mainly used for preheating the seed crystal, and the second heating element 9 is mainly used for heating the raw gas and granular silicon, so that the temperature of the core reaction zone of the inner wall of the reactor body is maintained within a normal control range, thereby realizing two-stage heating, improving the reaction time and area of ​​the raw gas and seed crystal, improving the output efficiency of the granular silicon product, improving the utilization rate of raw materials and equipment, and greatly reducing the operating cost.

[0045] In some specific embodiments of the utility model, the first heating element 8 is an electric heating belt, which is wound on the outer surface of the reactor body 1; the second heating element 9 includes a plurality of electric heating rods, which are arranged circumferentially along the reactor body 1. Preferably, 2-3 layers of 60-100 plug-in electric heating rods are evenly placed outside the middle section of the reactor body 1 to heat the seeds and raw gas in the fluidized state in the middle of the reactor body 1 to the required temperature for the reaction, so that the reaction temperature in the reactor body 1 is controlled at 400°C-600°C. 2-10 circles of electric heating belts are evenly placed outside the upper section of the reactor body 1 to maintain the temperature in the upper section of the reactor body 1 at 400°C-600°C, preheat the low-temperature seeds entering the upper end of the reactor body 1, and at the same time increase the reaction time and reaction section space for the seeds in the fluidized state and the raw gas to fully contact.

[0046] In some specific embodiments of the present invention, Figure 1 and Figure 2 As shown, an insulation layer 10 is provided outside the reactor body 1 for heat insulation and heat preservation; the insulation layer 10 is made of insulation materials such as rock wool, nano aerogel, aluminum silicate, etc. A furnace cover 11 is provided outside the insulation layer 10 to isolate the external air and keep the heat; the furnace cover 11 is made of carbon steel or stainless steel. It is preferred to introduce an inert gas (such as nitrogen) into the gap between the furnace cover 11 and the insulation layer 10 to maintain the internal pressure of the furnace cover 11 at 20-100kPaG. The inert gas atmosphere can not only protect the material of the insulation layer 10, but also prevent the reactor body 1 from leaking and causing safety accidents, thereby improving the operating safety of the equipment.

[0047] In some specific embodiments of the utility model, the reactor body 1 is made of materials such as high-purity silicon carbide, high-purity silicon nitride, single crystal silicon or graphite, and is formed into an integral barrel-shaped cavity by splicing, threaded connection or inlay connection, and is installed inside the furnace cover 11. These materials do not pollute the granular silicon product, and at the same time, impurities will not spread into the reactor body 1 and the granular silicon product under high temperature conditions. The shell of the reactor body 1 is preferably made of high-nickel alloy steel.

[0048] The method for producing granular silicon of the utility model comprises the following steps:

[0049] (1) Adding granular silicon seeds from the seed feed port 2 at the upper end of the reactor body 1, introducing raw gas from the raw gas feed port 4 at the bottom of the reactor body 1, and introducing auxiliary gas from the auxiliary gas feed port 3; the seeds move downward, the raw gas and auxiliary gas move upward, and the reactor body 1 is heated from the outside by a heating element, so that the inside of the reactor body 1 reaches the reaction temperature;

[0050] (2) The raw gas reacts to generate silicon, which is deposited on the surface of the seed crystal to form granular silicon. The granular silicon and its microsilicon powder are discharged from the granular silicon discharge port 5 at the bottom of the reactor body 1 to the granular silicon intermediate buffer tank, and the exhaust gas is discharged from the exhaust gas outlet 7 at the top of the reactor body 1.

[0051] In the utility model, the auxiliary gas enters the reactor body 1 from the outer periphery of the bottom of the reactor body 1 to form a gas curtain; the raw gas enters from the middle area of ​​the bottom of the reactor body 1 and is sprayed into the bottom of the reactor body 1. There is a pressure difference of 3-30kPaG between the bottom and the upper part of the reactor body 1. Under the action of the pressure difference, the raw gas flows evenly from bottom to top; the seed particles enter from the upper part of the reactor body 1 and flow from top to bottom under the action of gravity. The seed crystals and the raw gas form a bed of granular silicon materials in the middle area surrounded by the gas curtain. In the bed of granular silicon materials, the seed crystals and the raw gas are in a fluidized state, wherein the seed crystal filling rate is preferably 15%-80%, and the filling rate increases continuously from top to bottom. The reaction residence time of the seed crystals in the reactor body 1 is controlled by the addition amount of the seed crystals and the flow rate of the raw gas, and maintained in a relatively balanced and stable state. Due to the isolation effect of the gas curtain, the raw gas and the seed crystals react in the middle area surrounded by the gas curtain, thereby well avoiding the generated silicon from being deposited on the inner wall of the reactor body.

[0052] In a specific embodiment of the present invention, the particle size of the seed crystal is preferably 0.1-0.9 mm.

[0053] In the specific embodiment of the utility model, the raw gas is selected from a mixture of silane gas and hydrogen, hydrogen is used as a carrier gas, and silane gas is used as a main reaction gas. Before the raw gas enters the reactor body 1, it is preheated to 100-300°C and a pressure of 0.02-1MPaG by a preheater. The auxiliary gas of the utility model is selected from dichlorosilane or a mixture of dichlorosilane and hydrogen.

[0054] In the utility model, the outer area inside the reactor body 1 is mainly a dichlorosilane atmosphere, and the middle area is a silane gas and hydrogen atmosphere. When the outside of the reactor body 1 is heated to the reaction temperature, the silane gas is thermally decomposed into elemental silicon and hydrogen, and the elemental silicon is deposited on the seed crystal. As the deposition time increases, the particle size of the granular silicon continues to increase. Under the action of gravity, a granular silicon product is obtained at the bottom of the reactor body 1. Trace dichlorosilane is thermally decomposed into micro silicon powder and a small amount of hydrogen chloride gas at high temperature. Dichlorosilane is more difficult to decompose than silane gas. At the same time, compared with silane gas, when the same amount of raw gas is introduced, its dichlorosilane contains less silicon element, and the decomposed silicon is also relatively less, which can reduce the deposition of the decomposed silicon on the inner wall of the reactor body. In addition, hydrogen chloride is produced during the thermal decomposition of dichlorodihydrogen silicon. The hydrogen chloride reacts with silicon deposited on the inner wall of the reactor body, which can reduce the silicon deposited on the inner wall of the reactor body and form a dynamic reaction balance on the inner wall of the reactor body, that is, reducing the silicon deposited on the inner wall of the reactor body, while not affecting the reaction of the silane fluidized bed in the core reaction zone in the middle of the reactor.

[0055] The above content is only for explaining the technical idea of ​​the utility model and cannot be used to limit the protection scope of the utility model. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the utility model shall fall within the protection scope of the claims of the utility model.

Claims

1. A reactor for producing granular silicon, characterized in that: The invention comprises a reactor body (1) and a heating element arranged on the outer surface of the reactor body (1); a seed crystal feed port (2) is arranged on the top of the reactor body (1); an auxiliary gas feed port (3), a raw gas feed port (4) and a granular silicon discharge port (5) are arranged on the bottom plate of the reactor body (1); the auxiliary gas feed port (3) is distributed in a ring shape; and the raw gas feed port (4) and the granular silicon discharge port (5) are located in a ring surrounded by the auxiliary gas feed port (3).

2. The reactor for producing granular silicon according to claim 1, characterized in that: The ring formed by the auxiliary gas feed port (3) is coaxial with the reactor body (1), and the distance between the auxiliary gas feed port (3) and the inner wall of the reactor body (1) is 20-200 mm.

3. The reactor for producing granular silicon according to claim 1, characterized in that: A plurality of auxiliary gas feed inlets (3) are provided, and the plurality of auxiliary gas feed inlets (3) are distributed in a ring shape.

4. The reactor for producing granular silicon according to claim 1, characterized in that: The bottom plate of the reactor body (1) comprises a hollow first frustum and a hollow second frustum, the first frustum is located inside the second frustum, the upper base area of ​​the first frustum is smaller than the lower base area, the upper base area of ​​the second frustum is larger than the lower base area, the lower base of the first frustum is open, the upper base of the second frustum is open, the bottom of the first frustum is connected to the bottom of the second frustum via a platform; the granular silicon discharge port (5) is provided on the platform, the auxiliary gas feed port (3) is provided on the side wall of the second frustum; the raw gas feed port (4) is provided on the first frustum.

5. The reactor for producing granular silicon according to claim 1, characterized in that: The heating element comprises a first heating element (8) and a second heating element (9), wherein the first heating element (8) is located at the upper section of the reactor body (1), and the second heating element (9) is located at the middle section of the reactor body (1).

6. The reactor for producing granular silicon according to claim 5, characterized in that: The first heating element (8) is an electric heating belt, which is wound around the outer surface of the reactor body (1); the second heating element (9) comprises a plurality of electric heating rods, which are arranged along the circumference of the reactor body (1).

7. The reactor for producing granular silicon according to claim 6, characterized in that: The number of the electric heating rods is 60-100.

8. The reactor for producing granular silicon according to claim 1, characterized in that: A heat-insulating layer (10) is arranged outside the reactor body (1), and a furnace cover (11) is arranged outside the heat-insulating layer (10).

9. The reactor for producing granular silicon according to claim 8, characterized in that: The furnace hood (11) is provided with an inert gas inlet, and the inert gas inlet is used to introduce inert gas into the gap between the furnace hood (11) and the thermal insulation layer (10).

10. The reactor for producing granular silicon according to claim 1, characterized in that: A filter distributor (6) is provided at the raw gas feed inlet (4) and / or the auxiliary gas feed inlet (3).

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