Polycrystalline silicon production method and application thereof

Abstract

The invention discloses a polycrystalline silicon production method and application thereof, and the method comprises the following steps: carrying out reduction reaction on raw material hydrogen and trichlorosilane gas to obtain polycrystalline silicon; the total reaction time of the reduction reaction is T hours; when the reaction duration t of the reduction reaction meets the condition that t is more than or equal to 0 and less than n * T, the raw material hydrogen is high-temperature hydrogen with the flow rate of Q1 and the temperature of 120-150 DEG C; when the reaction duration t of the reduction reaction meets the condition that n * T < = t < = T, the raw material hydrogen comprises the high-temperature hydrogen and low-temperature hydrogen with the flow rate of Q2 and the temperature of 10-30 DEG C; 0.5 < = n < = 0.9; 0.1 < = Q2 / Q1 < = 0.5. The polycrystalline silicon production method provided by the invention has the characteristic of improving the proportion of the compact material in the polycrystalline silicon product.

Description

Technical Field

[0001] The invention relates to a polysilicon production method, in particular to a polysilicon production method and application thereof, belonging to the field of applied chemical industry. Background Art

[0002] The polysilicon reduction reaction is to mix trichlorosilane and hydrogen in a static mixer according to a specific feed molar ratio, and then enter the reduction furnace to undergo a reduction reaction. Trichlorosilane is reduced by hydrogen to silicon element and deposited on the surface of the silicon core, causing the diameter of the silicon rod to continue to increase until it reaches the specified size.

[0003] Due to the influence of reaction conditions during the reduction reaction cycle, different types of polysilicon products will be obtained, namely: dense material, loose material and coral material. Among them, dense material has the best performance and is the target product in the production process. When the reaction in the reduction furnace reaches the later stage, the temperature in the reduction furnace is high, the reduction reaction is not thorough, and it is easy to produce more coral material and loose material, which is not conducive to product quality.

[0004] Therefore, how to increase the proportion of dense material in polysilicon products has become a research direction in this field. Summary of the invention

[0005] The invention provides a polysilicon production method, which has the characteristic of increasing the proportion of dense material in the polysilicon product.

[0006] The present invention also provides a polysilicon production device, which has the characteristic of being able to increase the proportion of dense materials in the polysilicon product.

[0007] The present invention also provides a polysilicon production system, which has the characteristic of being able to produce polysilicon products with a high proportion of dense materials.

[0008] The present invention provides a method for producing polycrystalline silicon, which comprises the following steps:

[0009] The raw material hydrogen gas and trichlorosilane gas are subjected to a reduction reaction to obtain polycrystalline silicon;

[0010] The total reaction time of the reduction reaction is T hours;

[0011] When the reaction time t of the reduction reaction satisfies: 0≤t<n×T, the raw hydrogen is high-temperature hydrogen with a flow rate of Q1 and a temperature of 120-150°C;

[0012] When the reaction time t of the reduction reaction satisfies: n×T≤t≤T, the raw hydrogen includes the high-temperature hydrogen and also includes low-temperature hydrogen with a flow rate of Q2 and a temperature of 10-30°C;

[0013] 0.5≤n≤0.9;

[0014] 0.1≤Q2 / Q1≤0.5.

[0015] In the method as described above, when the raw hydrogen is the high-temperature hydrogen, the molar ratio of the raw hydrogen to the trichlorosilane gas is 1:3-1:6.

[0016] The method as described above, wherein 0.6≤n≤0.7.

[0017] The method as described above, wherein 0.25≤Q2 / Q1≤0.35.

[0018] The method as described above, wherein the reaction temperature of the reduction reaction is 1050-1150°C.

[0019] The present invention also provides a polysilicon production device for executing any of the above methods, which includes a reaction unit, a low-temperature hydrogen unit, a high-temperature hydrogen unit, a trichlorosilane unit, and a control unit;

[0020] The reaction unit is provided with N raw material inlets, N ≥ 1;

[0021] The logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the raw material inlet of the reaction unit;

[0022] The logistics outlet of the low-temperature hydrogen unit is connected to the raw material inlet of the reaction unit through the control unit.

[0023] The device as described above, wherein N=1, the reaction unit comprises a reduction furnace, and a first raw material inlet is provided at the bottom of the reduction furnace;

[0024] The logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the first raw material inlet of the reduction furnace;

[0025] The logistics outlet of the low-temperature hydrogen unit is connected to the first raw material inlet of the reduction furnace through the control unit.

[0026] The device as described above, wherein N=2, the reaction unit comprises a reduction furnace, a first raw material inlet is provided at the bottom of the reduction furnace, and a second raw material inlet is provided at the side wall of the reduction furnace;

[0027] The logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the first raw material inlet of the reduction furnace;

[0028] The logistics outlet of the low-temperature hydrogen unit is connected to the second raw material inlet of the reduction furnace through the control unit.

[0029] The device as described above, wherein, further comprises a mixing unit, and the logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the first raw material inlet of the reduction furnace through the mixing unit.

[0030] The present invention also provides a polysilicon production system, wherein the system comprises any one of the polysilicon production devices mentioned above.

[0031] The polysilicon production method provided by the present invention has the characteristic of increasing the proportion of dense material in the polysilicon product. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention 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 one by one below. Obviously, the drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0033] Figure 1 A structural diagram of a first polysilicon production device provided by the present invention;

[0034] Figure 2 An equipment diagram of a second polysilicon production device provided by the present invention;

[0035] Figure 3 An equipment diagram of a third polysilicon production device provided by the present invention;

[0036] Figure 4 This is an equipment diagram of a fourth polysilicon production device provided by the present invention.

[0037] Description of reference numerals:

[0038] A-reaction unit;

[0039] A1-reduction furnace;

[0040] B-cryogenic hydrogen unit;

[0041] B1- low temperature hydrogen source;

[0042] C-high temperature hydrogen unit;

[0043] C1-high temperature hydrogen source;

[0044] D-trichlorosilane unit;

[0045] D1-trichlorosilane source;

[0046] E-control unit;

[0047] E1-control valve;

[0048] F1 - Mixer. DETAILED DESCRIPTION

[0049] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0050] The first aspect of the present invention protects a method for producing polysilicon, the method comprising the following steps:

[0051] The raw material hydrogen gas and trichlorosilane gas are subjected to a reduction reaction to obtain polycrystalline silicon;

[0052] The total reaction time of the reduction reaction is T hours;

[0053] When the reaction time t of the reduction reaction satisfies: 0≤t<n×T, the raw hydrogen is high-temperature hydrogen with a flow rate of Q1 and a temperature of 120-150°C;

[0054] When the reaction time t of the reduction reaction satisfies: n×T≤t≤T, the raw hydrogen includes high-temperature hydrogen and low-temperature hydrogen with a flow rate of Q2 and a temperature of 10-30°C;

[0055] 0.5≤n≤0.9;

[0056] 0.1≤Q2 / Q1≤0.5.

[0057] Wherein, the total reaction time of the reduction reaction is the time from the start of the reduction reaction to the time when the reduction reaction stops at the end, which is recorded as T hours. The T value varies according to different production processes. Generally, 80h≤T≤120h. The total time of the reduction reaction can be adjusted according to different production requirements. In the present invention, the reaction time t is a point value falling in the interval of 0≤t≤T, representing the time difference between any time point in the middle of the reaction and the time point when the reaction starts.

[0058] In the polysilicon production method provided by the present invention, the reduction reaction consists of two stages, the first stage is a stage in which the reaction time t of the reduction reaction satisfies: 0≤t<n×T, and the second stage is a stage in which the reaction time t of the reduction reaction satisfies: n×T≤t≤T. Wherein, 0.5≤n≤0.9. That is, when n=0.6, T=1h, the first stage is from t=0h (reaction start) to t=0.6h, and the second stage is from t=0.6h to t=1h (reaction end).

[0059] Furthermore, in the first stage, that is, when the reaction time t of the reduction reaction satisfies: 0≤t<n×T, the raw hydrogen is high-temperature hydrogen with a flow rate of Q1 and a temperature of 120-150°C; in the second stage, when the reaction time t of the reduction reaction satisfies: n×T≤t≤T, the raw hydrogen includes the above-mentioned high-temperature hydrogen with a flow rate of Q1 and a temperature of 120-150°C, and also includes low-temperature hydrogen with a flow rate of Q2 and a temperature of 10-30°C, and the ratio of Q1 to Q2 satisfies 0.1≤Q2 / Q1≤0.5.

[0060] When hydrogen reacts with trichlorosilane, hydrogen can reduce trichlorosilane to silicon element and generate tail gas. The reduced silicon element is deposited as polysilicon product. Specifically, in the reduction furnace, hydrogen reacts with trichlorosilane gas, and trichlorosilane gas is reduced to silicon element at high temperature and deposited on silicon rods. Polysilicon products can be divided into dense material, loose material and coral material according to their density. Among them, dense material has the best performance. However, the current polysilicon production process has the defect that the quality proportion of dense material in polysilicon products is relatively low.

[0061] The inventors have discovered that in the current polysilicon production process, the reason why the mass proportion of dense material in the polysilicon product is relatively low is that in the later stage of the reduction reaction, the reaction temperature often rises to above 1200°C and the reaction temperature is uncontrollable. When the reaction temperature is high, the mass proportion of dense material in the obtained polysilicon product is relatively low.

[0062] In response to the above phenomenon, the inventors further studied and found that when the temperature rises in the later stage of the reduction reaction, the introduction of cold hydrogen at a lower temperature will result in a higher proportion of dense material in the obtained polysilicon product. The inventors speculate that the reason for the above phenomenon may be that when the reduction reaction reaches the last 1 / 3 stage of the reaction cycle, the additional introduction of cold hydrogen at a temperature of 10°C to 30°C as a reaction raw material can not only increase the proportion of hydrogen in the reaction gas and promote the reduction reaction, but also use the low temperature of the cold hydrogen to reduce the temperature in the reduction furnace, so that the reaction is carried out at the optimal reaction temperature, improve the quality of the polysilicon product, and increase the proportion of dense material in the product.

[0063] The present invention does not impose any specific limitation on the value of Q1, and it can be adjusted according to the production scale.

[0064] The polysilicon production method provided by the present invention has the characteristic of increasing the proportion of dense material in the polysilicon product.

[0065] In one embodiment, when the raw hydrogen is high-temperature hydrogen, the molar ratio of the raw hydrogen to trichlorosilane gas is 1:3-1:6. The molar ratio of hydrogen to trichlorosilane gas can further improve the quality of polysilicon products and make the proportion of dense materials in the obtained polysilicon products higher.

[0066] Furthermore, in one embodiment, 0.6≤n≤0.7. Cold hydrogen is introduced at an appropriate time during the reaction process to obtain a polysilicon product with a higher proportion of dense material.

[0067] Furthermore, in one embodiment, 0.25≤Q2 / Q1≤0.35. The molar ratio of low-temperature hydrogen to high-temperature hydrogen can not only increase the proportion of hydrogen in the reaction gas and promote the reduction reaction, but also further reduce the temperature in the reduction furnace, so that the proportion of dense material in the obtained polysilicon product is higher.

[0068] In one embodiment, the reaction temperature of the reduction reaction is 1050-1150° C. When the raw material hydrogen gas and trichlorosilane gas undergo a reduction reaction at a suitable reduction reaction temperature, a polysilicon product with a higher proportion of dense material can be obtained.

[0069] A second aspect of the present invention provides a polysilicon production device, which can be used to execute any polysilicon production method provided in the first aspect of the present invention. Figure 1 This is a structural diagram of the first polysilicon production device provided by the present invention, such as Figure 1 As shown, the device includes A-reaction unit, B-low temperature hydrogen unit, C-high temperature hydrogen unit, D-trichlorosilane unit, and E-control unit;

[0070] A-reaction unit is provided with N raw material inlets, N ≥ 1;

[0071] The logistics outlet of C-high temperature hydrogen unit and the logistics outlet of D-trichlorosilane unit are respectively connected to the raw material inlet of A-reaction unit;

[0072] The logistics outlet of the B-low-temperature hydrogen unit is connected to the raw material inlet of the A-reaction unit through the E-control unit.

[0073] In the polysilicon production device provided by the present invention, the B-low-temperature hydrogen unit provides low-temperature hydrogen, the C-high-temperature hydrogen unit provides high-temperature hydrogen, and the D-trichlorosilane unit provides trichlorosilane. The logistics outlet of the C-high-temperature hydrogen unit and the logistics outlet of the D-trichlorosilane unit are respectively connected to the raw material inlet of the A-reaction unit, and the logistics outlet of the B-low-temperature hydrogen unit is connected to the raw material inlet of the A-reaction unit through the E-control unit. Hydrogen and trichlorosilane undergo a reduction reaction in the A-reaction unit to generate a polysilicon product.

[0074] The present invention does not limit the specific selection of the above units. In one embodiment, B-low-temperature hydrogen unit is B1-low-temperature hydrogen source, C-high-temperature hydrogen unit is C1-high-temperature hydrogen source, trichlorosilane is D1-trichlorosilane source, and A-reaction unit includes A1-reduction furnace.

[0075] The A-reaction unit is provided with N raw material inlets, N ≥ 1, that is, the raw materials provided by the B-low-temperature hydrogen unit, the C-high-temperature hydrogen unit, and the D-trichlorosilane unit can enter the A-reaction unit through the same raw material inlet, or enter the A-reaction unit through different raw material inlets. The E-control unit has two states of opening and closing, and its function is to control whether the low-temperature hydrogen provided by the B-low-temperature hydrogen unit enters the A-reaction unit. When the E-control unit state is on, the low-temperature hydrogen can enter the A-reaction unit; when the E-control unit state is off, the low-temperature hydrogen cannot enter the A-reaction unit. The present invention does not limit the specific selection of the E-control unit. In one embodiment, the E-control unit is an E1-control valve.

[0076] When the above equipment is in operation, when the reaction time t satisfies: 0≤t<n×T, the E-control unit is in the off state, the C-high-temperature hydrogen unit provides high-temperature hydrogen, the D-trichlorosilane unit provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane enter the A-reaction unit for a reduction reaction; when the reaction time t satisfies: n×T≤t≤T, the E-control unit is in the on state, the B-low-temperature hydrogen unit provides low-temperature hydrogen, the C-high-temperature hydrogen unit provides high-temperature hydrogen, the D-trichlorosilane unit provides trichlorosilane, and the low-temperature hydrogen, high-temperature hydrogen and trichlorosilane enter the A-reaction unit at the same time for a reduction reaction.

[0077] The polysilicon production device provided by the present invention adds cold hydrogen to the reaction system in the second half of the reaction according to different reaction times, which can not only increase the hydrogen ratio in the reaction gas and promote the reduction reaction, but also use the low temperature of the cold hydrogen to reduce the temperature increased in the Al-reduction furnace, so that the reaction is carried out at the optimal reaction temperature, improve the quality of the polysilicon product, and make the proportion of dense materials in the obtained polysilicon product higher. The device has the characteristics of being able to produce polysilicon products with a high proportion of dense materials.

[0078] In one embodiment, N=1, the A-reaction unit includes an A1-reduction furnace, and a first raw material inlet is provided at the bottom of the A1-reduction furnace; the logistics outlet of the C-high-temperature hydrogen unit and the logistics outlet of the D-trichlorosilane unit are respectively connected to the first raw material inlet of the A1-reduction furnace; the logistics outlet of the B-low-temperature hydrogen unit is connected to the first raw material inlet of the A1-reduction furnace through the E-control unit. In this embodiment, the high-temperature hydrogen, trichlorosilane and low-temperature hydrogen all enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace, and a reduction reaction occurs.

[0079] In another embodiment, N=2, the A-reaction unit includes an A1-reduction furnace, the bottom of the A1-reduction furnace is provided with a first raw material inlet, and the side wall of the A1-reduction furnace is provided with a second raw material inlet; the logistics outlet of the C-high-temperature hydrogen unit and the logistics outlet of the D-trichlorosilane unit are respectively connected to the first raw material inlet of the A1-reduction furnace; the logistics outlet of the B-low-temperature hydrogen unit is connected to the second raw material inlet of the A1-reduction furnace through the E-control unit. In this embodiment, the side wall of the A1-reduction furnace is provided with a second raw material inlet, the logistics outlet of the B-low-temperature hydrogen unit is connected to the second raw material inlet of the A1-reduction furnace through the E-control unit, and the low-temperature hydrogen enters the A1-reduction furnace through the second raw material inlet of the A1-reduction furnace; the logistics outlet of the C-high-temperature hydrogen unit and the logistics outlet of the D-trichlorosilane unit are respectively connected to the first raw material inlet of the A1-reduction furnace, and the high-temperature hydrogen and trichlorosilane enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace.

[0080] This aspect does not limit the positional relationship between the first raw material inlet and the second raw material inlet of the A1-reduction furnace. In one embodiment, the first raw material inlet is located at the bottom of the A1-reduction furnace, the second raw material inlet is located at the side wall of the A1-reduction furnace, and the elevation of the second raw material inlet is higher than the elevation of the first raw material inlet.

[0081] In one embodiment, the polysilicon production device provided by the present invention also includes a mixing unit, and the logistics outlet of the C-high-temperature hydrogen unit and the logistics outlet of the D-trichlorosilane unit are respectively connected to the first raw material inlet of the A1-reduction furnace through the mixing unit.

[0082] The function of the mixing unit is to evenly mix different raw materials to improve the efficiency of the reduction reaction. The present invention does not limit the specific equipment selection of the mixing unit. In one embodiment, the mixing unit is an F1-mixer.

[0083] Figure 2 1 is a diagram of the equipment of the second polysilicon production device provided by the present invention. Figure 2 As shown, the device includes A1-reduction furnace, B1-low-temperature hydrogen source, C1-high-temperature hydrogen source, D1-trichlorosilane source, F1-mixer, and E1-control valve. Among them, A1-reduction furnace is A-reaction unit, B1-low-temperature hydrogen source is B-low-temperature hydrogen unit, C1-high-temperature hydrogen source is C-high-temperature hydrogen unit, D1-trichlorosilane source is D-trichlorosilane unit, and F1-mixer is a mixing unit. A1-reduction furnace includes a first raw material inlet located at the bottom. C1-high-temperature hydrogen source and D1-trichlorosilane source are connected to the first raw material inlet of A1-reduction furnace through F1-mixer respectively, and B1-low-temperature hydrogen source is connected to the first raw material inlet of A1-reduction furnace through E1-control valve.

[0084] When the above equipment is in operation, when the reaction time t satisfies: 0≤t<n×T, the E1-control valve is in the closed state, the C1-high-temperature hydrogen source provides high-temperature hydrogen, the D1-trichlorosilane source provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, and then enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; when the reaction time t satisfies: n×T≤t≤T, the E1-control valve is in the open state, the B1-low-temperature hydrogen source provides low-temperature hydrogen, the C1-high-temperature hydrogen source provides high-temperature hydrogen, and the D1-trichlorosilane source provides trichlorosilane, and after the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, they enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; the low-temperature hydrogen enters the A1-reduction furnace directly through the E1-control valve through the first raw material inlet of the A1-reduction furnace.

[0085] Figure 3 1 is a diagram of the equipment of the third polysilicon production device provided by the present invention. Figure 3 As shown, the device includes A1-reduction furnace, B1-low-temperature hydrogen source, C1-high-temperature hydrogen source, D1-trichlorosilane source, F1-mixer, and E1-control valve. Among them, A1-reduction furnace is A-reaction unit, B1-low-temperature hydrogen source is B-low-temperature hydrogen unit, C1-high-temperature hydrogen source is C-high-temperature hydrogen unit, D1-trichlorosilane source is D-trichlorosilane unit, and F1-mixer is mixing unit. A1-reduction furnace includes a first raw material inlet located at the bottom. C1-high-temperature hydrogen source and D1-trichlorosilane source are connected to the first raw material inlet of A1-reduction furnace through F1-mixer respectively, and B1-low-temperature hydrogen source is first mixed with high-temperature hydrogen, and then connected to the first raw material inlet of A1-reduction furnace through E1-control valve and F1-mixer in sequence.

[0086] When the above equipment is in operation, when the reaction time t satisfies: 0≤t<n×T, the E1-control valve is in the closed state, the C1-high-temperature hydrogen source provides high-temperature hydrogen, the D1-trichlorosilane source provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, and then enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; when the reaction time t satisfies: n×T≤t≤T, the E1-control valve is in the open state, the B1-low-temperature hydrogen source provides low-temperature hydrogen, the C1-high-temperature hydrogen source provides high-temperature hydrogen, and the D1-trichlorosilane source provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, and then enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; the low-temperature hydrogen enters the A1-reduction furnace through the E1-control valve and the F1-mixer through the first raw material inlet of the A1-reduction furnace.

[0087] Figure 4 1 is a diagram of the fourth polysilicon production device provided by the present invention. Figure 4As shown, the device includes A1-reduction furnace, B1-low-temperature hydrogen source, C1-high-temperature hydrogen source, D1-trichlorosilane source, F1-mixer, and E1-control valve. Among them, A1-reduction furnace is A-reaction unit, B1-low-temperature hydrogen source is B-low-temperature hydrogen unit, C1-high-temperature hydrogen source is C-high-temperature hydrogen unit, D1-trichlorosilane source is D-trichlorosilane unit, and F1-mixer is mixing unit. A1-reduction furnace includes a first raw material inlet and a second raw material inlet, the first raw material inlet is located at the bottom of A1-reduction furnace, and the second raw material inlet is located at the side wall of A1-reduction furnace. C1-high-temperature hydrogen source and D1-trichlorosilane source are connected to the first raw material inlet of A1-reduction furnace through F1-mixer respectively, and B1-low-temperature hydrogen source is connected to the second raw material inlet of A1-reduction furnace through E1-control valve.

[0088] When the above equipment is in operation, when the reaction time t satisfies: 0≤t<n×T, the E1-control valve is in the closed state, the C1-high-temperature hydrogen source provides high-temperature hydrogen, the D1-trichlorosilane source provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, and then enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; when the reaction time t satisfies: n×T≤t≤T, the E1-control valve is in the open state, the B1-low-temperature hydrogen source provides low-temperature hydrogen, the C1-high-temperature hydrogen source provides high-temperature hydrogen, and the D1-trichlorosilane source provides trichlorosilane, and after the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, they enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; the low-temperature hydrogen enters the A1-reduction furnace via the E1-control valve and the second raw material inlet of the A1-reduction furnace.

[0089] The third aspect of the present invention provides a polysilicon production system, which includes any polysilicon production equipment provided by the second aspect of the present invention. Since the polysilicon production equipment provided by the second aspect of the present invention has the characteristic of increasing the proportion of dense materials in the polysilicon product, the polysilicon production system provided by the third aspect of the present invention has the characteristic of being able to produce polysilicon products with a high proportion of dense materials.

[0090] The polysilicon production method and application provided by the present invention are described in detail below through specific embodiments.

[0091] Example 1

[0092] This embodiment will Figure 4 The polysilicon production equipment shown is used for the production of polysilicon. Wherein, T = 80 hours, n = 0.65, Q2 / Q1 = 0.3. When the raw material hydrogen is high-temperature hydrogen, the molar ratio of the raw material hydrogen to trichlorosilane gas is 1:4.5.

[0093] When the above equipment is in operation, when the reaction time t satisfies: 0≤t<n×T, the E1-control valve is in the closed state, the C1-high-temperature hydrogen source provides high-temperature hydrogen, the D1-trichlorosilane source provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, and then enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; when the reaction time t satisfies: n×T≤t≤T, the E1-control valve is in the open state, the B1-low-temperature hydrogen source provides low-temperature hydrogen, the C1-high-temperature hydrogen source provides high-temperature hydrogen, and the D1-trichlorosilane source provides trichlorosilane, and the high-temperature hydrogen and trichlorosilane are mixed in the F1-mixer, and then enter the A1-reduction furnace through the first raw material inlet of the A1-reduction furnace to undergo a reduction reaction; the low-temperature hydrogen enters the A1-reduction furnace through the E1-control valve and the F1-mixer through the first raw material inlet of the A1-reduction furnace.

[0094] In the description of the embodiments of the present application, it should be noted that, 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 it can be an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0095] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present application and the above-mentioned drawings 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 interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising 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.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for producing polycrystalline silicon, characterized in that: The steps include: The raw material hydrogen gas and trichlorosilane gas are subjected to a reduction reaction to obtain polycrystalline silicon; The total reaction time of the reduction reaction is T hours; When the reaction time t of the reduction reaction satisfies: 0≤t<n×T, the raw hydrogen is high-temperature hydrogen with a flow rate of Q1 and a temperature of 120-150°C; When the reaction time t of the reduction reaction satisfies: n×T≤t≤T, the raw hydrogen includes the high-temperature hydrogen and also includes low-temperature hydrogen with a flow rate of Q2 and a temperature of 10-30°C; 0.5≤n≤0.9; 0.1≤Q2 / Q1≤0.

5.

2. The method according to claim 1, characterized in that When the raw hydrogen is the high-temperature hydrogen, the molar ratio of the raw hydrogen to the trichlorosilane gas is 1:3-1:

6.

3. The method according to claim 1 or 2, characterized in that: 0.6≤n≤0.7。 4. The method according to any one of claims 1 to 3, characterized in that 0.25≤Q2 / Q1≤0.

35.

5. The method according to any one of claims 1 to 4, characterized in that The reaction temperature of the reduction reaction is 1050-1150°C.

6. A polysilicon production device for executing the method according to any one of claims 1 to 5, characterized in that: It includes a reaction unit, a low-temperature hydrogen unit, a high-temperature hydrogen unit, a trichlorosilane unit and a control unit; The reaction unit is provided with N raw material inlets, N ≥ 1; The logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the raw material inlet of the reaction unit; The logistics outlet of the low-temperature hydrogen unit is connected to the raw material inlet of the reaction unit through the control unit.

7. The device according to claim 6, characterized in that N=1, the reaction unit includes a reduction furnace, and a first raw material inlet is provided at the bottom of the reduction furnace; The logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the first raw material inlet of the reduction furnace; The logistics outlet of the low-temperature hydrogen unit is connected to the first raw material inlet of the reduction furnace through the control unit.

8. The device according to claim 6, characterized in that N=2, the reaction unit comprises a reduction furnace, a first raw material inlet is provided at the bottom of the reduction furnace, and a second raw material inlet is provided on the side wall of the reduction furnace; The logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the first raw material inlet of the reduction furnace; The logistics outlet of the low-temperature hydrogen unit is connected to the second raw material inlet of the reduction furnace through the control unit.

9. The device according to claim 7 or 8, characterized in that It also includes a mixing unit, and the logistics outlet of the high-temperature hydrogen unit and the logistics outlet of the trichlorosilane unit are respectively connected to the first raw material inlet of the reduction furnace through the mixing unit.

10. A polysilicon production system, characterized in that: A polysilicon production device comprising any one of claims 6-9.

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