Polycrystalline silicon reduction furnace nozzle and polycrystalline silicon reduction furnace

Abstract

The utility model discloses a polycrystalline silicon reduction furnace nozzle and a polycrystalline silicon reduction furnace, which can improve the spraying height of the polycrystalline silicon reduction furnace nozzle and solve the problem of non-uniform temperature field and flow field in the reduction furnace. The polycrystalline silicon reduction furnace nozzle is provided with an inner hole, and the inner hole comprises an elliptical runner section (4), a transition section and a rectification section (6) which are communicated in sequence; the aperture of an inner hole from the elliptical runner section (4) to the transition section is gradually reduced, and the aperture of the top end of the transition section is the same as that of the bottom end of the rectification section (6); the longitudinal section of the elliptical runner section (4) is in a semi-elliptical shape; and the rectification section (6) is cylindrical.

Description

Technical Field

[0001] The utility model belongs to the technical field of polysilicon, and particularly relates to a polysilicon reduction furnace nozzle and a polysilicon reduction furnace. Background Art

[0002] With the increasing demand for new energy in society, as a reliable carrier of new energy technology, the related process technology of photovoltaic power generation is also rapidly developing towards large-scale and high-end. As an upstream industry of photovoltaic, the current mainstream products of polysilicon production are rod-shaped silicon and granular silicon. Among them, rod-shaped silicon is mainly produced by the improved Siemens method, which is also the process commonly used in the industry. The downstream industry of photovoltaic has continuously improved the purity requirements for polysilicon, and also the requirements for the impurity content and appearance of polysilicon.

[0003] The polysilicon reduction furnace is the terminal link of polysilicon production. The polysilicon reduction furnace nozzle is used to spray raw material gases (trichlorosilane and hydrogen in a certain ratio) into the polysilicon reduction furnace through the nozzle. In the polysilicon reduction furnace, these gases undergo a gas-phase reduction reaction, and the finally generated silicon (Si) is directly deposited on the surface of the silicon core in the reduction furnace. Therefore, the stability of the feed flow field and temperature field in the furnace is crucial for the quality of the silicon rod. From the perspective of the selection of the feed nozzle, if its spraying height is insufficient, it will affect the stability of the feed flow field and temperature field in the furnace during the reaction, resulting in slow material renewal of the silicon rod crossbeam, high temperature at the top of the silicon rod, and prone to adverse phenomena such as silicon core radiation and large-head rods. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a polysilicon reduction furnace nozzle and a polysilicon reduction furnace in view of the above deficiencies existing in the prior art. By using the nozzle with this structure, the spraying height of the polysilicon reduction furnace nozzle can be increased, thereby improving the problem of uneven temperature field and flow field in the reduction furnace.

[0005] In the first aspect, an embodiment of the utility model provides a polysilicon reduction furnace nozzle. The polysilicon reduction furnace nozzle has an inner hole, and the inner hole includes an elliptical flow channel section, a transition section, and a rectifying section that are sequentially connected. The aperture of the inner hole from the elliptical flow channel section to the transition section gradually decreases, and the aperture at the top of the transition section is the same as the aperture at the bottom of the rectifying section. The longitudinal section of the elliptical flow channel section is in the shape of a semi-ellipse; the rectifying section is in the shape of a cylinder.

[0006] In some embodiments, in the elliptical flow channel section, the length of the minor axis of the ellipse is D2, and half of the length of the major axis of the ellipse is L2, then

[0007] In some embodiments, in the rectifying section, the diameter of the cylinder is D1, and / or, the height of the transition section is less than or equal to

[0008] In some embodiments, the nozzle of the polysilicon reduction furnace includes a conical portion and a cylindrical portion. The lower part of the conical portion communicates with the cylindrical portion. The elliptical flow channel section is inside the cylindrical portion and extends into the conical portion. The transition section and the rectifying section are both inside the conical portion.

[0009] In some embodiments, the cone angle of the conical portion is α, where 10° ≤ α ≤ 15°; and / or, the outer diameter of the cylindrical portion is D3, where 35 mm ≤ D3 ≤ 55 mm; and / or, the height of the nozzle of the polysilicon reduction furnace is w, and the height of the cylindrical portion is w2.

[0010] In some embodiments, the upper end face of the conical portion is an arc surface, and the outer wall surface of the conical portion is connected to the inner wall surface of the rectifying section through the arc surface.

[0011] In some embodiments, anti-corrosion coatings with infrared reflection functions are coated on the outer wall surfaces of both the conical portion and the cylindrical portion.

[0012] In some embodiments, side flow channels are provided on the side wall of the conical portion for leading out some of the gas in the inner hole to the outside of the nozzle of the polysilicon reduction furnace; in the direction from the inside to the outside, the side flow channels extend obliquely upward and penetrate the side wall of the conical portion. The starting point of the side flow channel corresponds to the position in the upper middle part of the elliptical flow channel section, and the ending point of the side flow channel corresponds to the position in the lower part of the conical portion.

[0013] In some embodiments, the number of the side flow channels is n, and the n side flow channels are arranged at intervals in sequence at the same height of the conical portion and are evenly distributed around the axis of the conical portion; where n is a positive integer and 2 ≤ n ≤ 8.

[0014] In some embodiments, along the gas flow direction, the side flow channel includes a first straight line segment, a first arc segment, a second straight line segment, a second arc segment, and a third straight line segment that are connected in sequence. The center line of the first arc segment is tangent to the center line of the first straight line segment and the center line of the second straight line segment respectively. The center line of the second arc segment is tangent to the center line of the second straight line segment and the center line of the third straight line segment respectively; where, the angle between the center line of the first straight line segment and the vertical direction is A3, 0° ≤ A3 ≤ 8°; and / or, the angle between the center line of the second straight line segment and the horizontal direction is A2, 30° ≤ A2 ≤ 60°; and / or, the angle between the center line of the third straight line segment and the outer wall surface of the conical portion is A1, 15° ≤ A1 ≤ 25°.

[0015] In some embodiments, in the radial direction of the polysilicon reduction furnace nozzle, the width of the side flow channel is k, and 0.5 mm ≤ k ≤ 3 mm.

[0016] In some embodiments, the longitudinal section of the transition section is arc-shaped, the lower end of the longitudinal section of the transition section is tangent to the upper end of the longitudinal section of the elliptical flow channel section, and the upper end of the longitudinal section of the transition section is tangent to the lower end of the longitudinal section of the straightening section.

[0017] Therefore, the polysilicon reduction furnace nozzle provided in the embodiment of the utility model can gradually increase the flow rate of the gas entering the elliptical flow channel section and the transition section by setting the elliptical flow channel section, the transition section, and the rectifying section in the inner hole of the polysilicon reduction furnace nozzle in sequence, and gradually reducing the aperture of the inner hole from the elliptical flow channel section to the transition section; by making the aperture of the top of the transition section the same as the aperture of the bottom of the rectifying section, it can avoid the gas from generating vortexes due to the sudden change of the aperture at the connection position of the transition section and the rectifying section, thereby avoiding the loss of kinetic energy of the gas, and the rectifying section can converge and rectify the gas and then spray it out from the nozzle at a uniform speed. Therefore, the polysilicon reduction furnace nozzle in the embodiment of the utility model can increase the flow rate of the gas when it is sprayed from the polysilicon reduction furnace nozzle, thereby increasing the injection height of the gas raw material sprayed from the polysilicon reduction furnace nozzle, improving the problem of uneven temperature field and flow field in the reduction furnace, and then improving the problem of high temperature at the top of the silicon rod, reducing the occurrence of undesirable phenomena such as silicon core radiation and large head rods, and improving the quality of silicon rods.

[0018] In a second aspect, an embodiment of the utility model provides a polysilicon reduction furnace, which includes a furnace body and the polysilicon reduction furnace nozzle in the first aspect. The furnace body has a chassis at the bottom, and the chassis has a plurality of air inlet branches. The polysilicon reduction furnace nozzle is fixed on the chassis.

[0019] The polysilicon reduction furnace provided by the embodiment of the utility model has the same beneficial effects as the above-mentioned polysilicon reduction furnace nozzle, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 : A schematic diagram of a polysilicon reduction furnace nozzle provided by an embodiment of the utility model;

[0021] Figure 2 : A cross-sectional view of a polysilicon reduction furnace nozzle provided by an embodiment of the utility model;

[0022] Figure 3 : A half-section view of a nozzle of a polysilicon reduction furnace provided by an embodiment of the utility model;

[0023] Figure 4 :for Figure 3 A partial magnified image of the middle Q region;

[0024] Figure 5 : It is a top view of a nozzle for a polysilicon reduction furnace provided by an embodiment of the present invention;

[0025] Figure 6 : It is a temperature simulation diagram of a nozzle for a polysilicon reduction furnace;

[0026] Figure 7 : It is a schematic diagram of a polysilicon reduction furnace provided by an embodiment of the present invention. Detailed implementation manners

[0027] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0028] Embodiment 1:

[0029] As Figure 1 and Figure 2 shown, an embodiment of the present invention provides a nozzle 7 for a polysilicon reduction furnace, which is applied to the production process of polysilicon. As Figure 1 and Figure 2 shown, the nozzle 7 for the polysilicon reduction furnace has an inner hole, and the inner hole includes an elliptical flow channel section 4, a transition section, and a rectifying section 6 that are connected in sequence. The aperture of the inner hole from the elliptical flow channel section 4 to the transition section gradually becomes smaller, and the aperture at the top of the transition section is the same as the aperture at the bottom of the rectifying section. The longitudinal section of the elliptical flow channel section 4 is in the shape of a semi-ellipse; the rectifying section 6 is in the shape of a cylinder.

[0030] Exemplarily, the material of the nozzle 7 for the polysilicon reduction furnace can be a metal material such as stainless steel.

[0031] Exemplarily, as Figure 2 shown, the semi-ellipse of the elliptical flow channel section 4 extends into the transition section after extension.

[0032] The aperture of the inner hole from the elliptical flow channel section 4 to the transition section gradually becomes smaller. After the gas enters the elliptical flow channel section 4 and the transition section, the flow rate will increase due to the converging effect.

[0033] The transition section is used to make the gas in the elliptical flow channel section 4 flow smoothly into the rectifying section 6, and to avoid the generation of eddy currents due to the different apertures of the elliptical flow channel section 4 and the rectifying section 6.

[0034] The rectifying section 6 can converge and rectify the incoming gas, so that the gas can be ejected smoothly from the nozzle 3.

[0035] As Figure 1 and Figure 2As shown, the aperture of the inner hole from the elliptical flow channel section 4 to the transition section gradually becomes smaller. After the gas enters the elliptical flow channel section 4, the elliptical flow channel section 4 has a good acceleration effect on the gas, and the flow rate of the gas will gradually increase. After the gas enters the transition section, the flow rate of the gas will continue to increase; because the aperture at the top of the transition section is the same as the aperture at the bottom of the rectifying section, therefore, when the gas enters the rectifying section 6 from the transition section, the sudden change in the aperture at the connection position between the transition section and the rectifying section 6 can be avoided to generate vortices, thereby avoiding the loss of kinetic energy of the gas; because the shape of the rectifying section 6 is cylindrical, the flow rate of the gas does not change much when entering the rectifying section 6, and the rectifying section 6 can converge and rectify the gas and then spray it out from the nozzle 3 at a uniform speed.

[0036] Therefore, through the above-mentioned settings, the flow rate of the gas ejected from the nozzle 7 of the polysilicon reduction furnace can be increased, the injection height of the gas raw material ejected from the nozzle 7 of the polysilicon reduction furnace can be increased, and the problems of uneven temperature field and flow field in the reduction furnace can be improved, thereby improving the problem of high temperature at the top of the silicon rod, reducing the occurrence of adverse phenomena such as silicon core radiation and big-headed rods, and improving the density of the silicon rod while maintaining the reduction power consumption at a constant level.

[0037] Furthermore, the increase in the gas flow rate can also remove the heat from the nozzle 7 of the polysilicon reduction furnace more quickly, which is beneficial to the cooling of the nozzle 7 of the polysilicon reduction furnace.

[0038] Therefore, the polysilicon reduction furnace nozzle 7 provided in the embodiment of the utility model can gradually increase the flow rate of the gas entering the elliptical flow channel section 4 and the transition section by setting the elliptical flow channel section 4, the transition section, and the rectifying section 6 that are connected in sequence in the inner hole of the polysilicon reduction furnace nozzle 7, and gradually reducing the aperture of the inner hole from the elliptical flow channel section 4 to the transition section; by making the aperture of the top of the transition section the same as the aperture of the bottom of the rectifying section, it can be avoided that the gas generates vortices due to the sudden change of the aperture at the connection position of the transition section and the rectifying section 6, thereby avoiding the kinetic energy loss of the gas, and the rectifying section 6 can converge and rectify the gas and then spray it out from the nozzle 3 at a uniform speed. Therefore, the polysilicon reduction furnace nozzle 7 in the embodiment of the utility model can increase the flow rate of the gas when it is sprayed from the polysilicon reduction furnace nozzle 7, thereby increasing the injection height of the gas raw material sprayed from the polysilicon reduction furnace nozzle 7, improving the problem of uneven temperature field and flow field in the reduction furnace, and then improving the problem of high temperature at the top of the silicon rod, reducing the occurrence of undesirable phenomena such as silicon core radiation and large head rods, and improving the quality of silicon rods.

[0039] In some embodiments, Figure 2 As shown, in the elliptical flow channel section 4, the length of the short axis of the ellipse is D2, and half of the length of the long axis of the ellipse is L2, then

[0040]

[0041] like Figure 2As shown, at this time, the height of the remaining part of the polysilicon reduction furnace nozzle 7 is L1.

[0042] Exemplarily, The value of can be 2, 2.5, 3, etc.

[0043] In some examples, 25mm ≤ D2 ≤ 35mm.

[0044] Exemplarily, the value of D2 can be 25mm, 30mm, or 35mm.

[0045] When the value of D2 is 30mm, according to Then 30mm ≤ L2 ≤ 45mm.

[0046] The inventor found that since The value of is the ratio of the major axis to the minor axis of the ellipse. When the ratio of the major axis to the minor axis is larger, the shape of the ellipse is flatter, the aperture change rate of the elliptical flow channel section is smaller, and the gas flows more smoothly when passing through the elliptical flow channel section 4; when the ratio of the major axis to the minor axis is smaller, the shape of the ellipse is closer to a circle, the aperture change rate of the elliptical flow channel section is larger, and the flow velocity change of the gas when passing through the elliptical flow channel section 4 is larger, and a greater flow velocity can be obtained.

[0047] By reasonably adjusting the value, a higher acceleration effect of the gas in the elliptical flow channel section 4 can be obtained. In this embodiment, by setting the value to a better acceleration effect can be obtained.

[0048] In some embodiments, as Figure 2 shown, in the rectifying section 6, the diameter of the cylinder is D1,

[0049] Exemplarily, The value of can be 2.5, 5, 7, etc.

[0050] Among them, the diameter D1 of the cylinder is the size of the nozzle 3 of the polysilicon reduction furnace nozzle 7.

[0051] The diameter D1 of the cylinder can be selected according to the actual production situation. Exemplarily, 5mm ≤ D1 ≤ 16mm.

[0052] For example, the value of D1 can be 5mm, 9mm, 12mm, 16mm, etc.

[0053] As described above, when the value of D2 is 35mm and at this time, the value range of D1 is: 5mm ≤ D1 ≤ 14mm.

[0054] As Figure 2As shown, the inventor found that the gas enters the interior of the polysilicon reduction furnace nozzle 7 from the bottom of the polysilicon reduction furnace nozzle 7 and is ejected from the nozzle orifice 3 at the top of the polysilicon reduction furnace nozzle 7. The value of determines the aperture change rate of the polysilicon reduction furnace nozzle 7. The larger the value of , the greater the aperture change rate of the polysilicon reduction furnace nozzle 7, and the greater the acceleration effect of the polysilicon reduction furnace nozzle 7 on the gas. The smaller the value of , the smaller the aperture change rate of the polysilicon reduction furnace nozzle 7, and the smaller the acceleration effect of the polysilicon reduction furnace nozzle 7 on the gas.

[0055] In some examples, the height of the transition section can be set to be less than or equal to

[0056] As described above, the value range of L2 can be: 30mm ≤ L2 ≤ 45mm. When the value of L2 is 40mm, the height of the transition section is less than or equal to 5.

[0057] For example, the height of the transition section is 3mm, 4mm or 5mm, etc.

[0058] The top end of the transition section is connected to the bottom end of the rectifying section 6, and the bottom end of the transition section is connected to the top end of the elliptical flow channel section 4, for enabling the gas in the elliptical flow channel section 4 to flow into the rectifying section 6. When there is a large difference between the aperture at the top end of the elliptical flow channel section 4 and the aperture at the bottom end of the rectifying section 6, the height of the transition section can be set larger, so that the aperture change rate of the transition section becomes smaller, so that the resistance of the gas in the elliptical flow channel section 4 when passing through the transition section is smaller, avoiding reducing the kinetic energy of the gas; when there is a small difference between the aperture at the top end of the elliptical flow channel section 4 and the aperture at the bottom end of the rectifying section 6, even if the height of the transition section is set smaller, the aperture change rate of the transition section can also be made smaller, so that the resistance of the gas in the elliptical flow channel section 4 when passing through the transition section is smaller, avoiding reducing the kinetic energy of the gas.

[0059] Currently, the feed temperature (the temperature of the gas entering the polysilicon reduction furnace nozzle 7) in the polysilicon reduction furnace is 120°C - 140°C, and the temperature of the furnace atmosphere is 600°C - 700°C. In the prior art, the outer shapes of the nozzles commonly used at present are all cylindrical. Actual production shows that the top of the nozzle will be severely corroded due to high-temperature radiation, and the nozzle with an overall height exceeding 50mm is more severely corroded. The metal elements after the nozzle is corroded will enter the silicon rod, having a certain impact on the metal content of the silicon rod.

[0060] In one technical document (CN212504016U, a sinking reduction furnace nozzle), the exposed part of the nozzle is shortened to 5mm-10mm, and the nozzle body is sunk into the water-cooling chamber of the reduction furnace chassis, thereby reducing the nozzle surface temperature and slowing down the corrosion of the nozzle. In another technical document (CN207861899U, an adjustable polysilicon reduction furnace nozzle 7), an air intake structure is provided to adjust the height of the nozzle in the reduction furnace through a spiral transmission to achieve the flow field adjustment in the furnace. However, in combination with actual production conditions, in the above two documents, the nozzle height is too low, which will affect the uniformity of the flow field in the reduction furnace, and the wall flow on the chassis will disturb the feed and will also cause bias flow.

[0061] Based on this, in some embodiments of this embodiment, such as Figure 1 and Figure 3 As shown, the polysilicon reduction furnace nozzle 7 includes a conical portion 2 and a cylindrical portion 11. The lower portion of the conical portion 2 is connected to the cylindrical portion 11. The elliptical flow channel section 4 is located inside the cylindrical portion 11 and extends to the inside of the conical portion 2. The transition section and the straightening section 6 are both located inside the conical portion 2.

[0062] like Figure 1 As shown, the outer diameter of the cylindrical portion 11 is larger, so that there can be more space openings inside it to form an elliptical flow channel section 4, so that the inlet of the elliptical flow channel section 4 has a larger size to allow more gas to enter the polysilicon reduction furnace nozzle 7, which can increase the air intake amount entering the polysilicon reduction furnace nozzle 7, which is beneficial to increase the flow rate of the gas finally ejected from the polysilicon reduction furnace nozzle 7.

[0063] It can be understood that if the polysilicon reduction furnace nozzle 7 is cylindrical, the side walls of the polysilicon reduction furnace nozzle 7 corresponding to the upper portion of the elliptical flow channel section 4, the transition section and the rectifying section 6 will be thicker.

[0064] By setting the cone portion 2, the side wall thickness at the position corresponding to the cone portion 2 in the polysilicon reduction furnace nozzle 7 is reduced, so that the low-temperature gas can take away the heat from the top and the side wall of the nozzle through the side wall, thereby reducing the temperature of the polysilicon reduction furnace nozzle 7 and avoiding corrosion of the polysilicon reduction furnace nozzle 7 due to high-temperature radiation, thereby reducing the content of metal elements entering the polysilicon reduction furnace atmosphere, reducing the metal content in the silicon rods finally formed, and improving the quality of the silicon rods.

[0065] In some examples, the cone angle of the cone portion 2 is α, 10°≤α≤15°.

[0066] For example, the cone angle α of the cone portion 2 may be 10°, 12°, 15°, etc.

[0067] Combination Figure 2, It can be understood that by adjusting the cone angle α of the conical part 2, the wall thickness above the nozzle 7 of the polysilicon reduction furnace can be adjusted, thereby affecting the strength and heat conduction rate above the nozzle 7 of the polysilicon reduction furnace.

[0068] By setting the cone angle α of the conical part 2 to 10° ≤ α ≤ 15°, the upper part of the nozzle 7 of the polysilicon reduction furnace can have relatively high strength and heat conduction rate.

[0069] In some examples, as Figure 2 shown, the outer diameter of the cylindrical part 11 is D3, and 35 mm ≤ D3 ≤ 55 mm.

[0070] Exemplarily, the outer diameter D3 of the cylindrical part 11 can be 35 mm, 45 mm or 55 mm, etc.

[0071] It can be understood that in combination with Figure 2 , the larger the outer diameter D3 of the cylindrical part 11, the larger the maximum aperture of the elliptical flow channel section 4 can be made, and the wall thickness of the cylindrical part 11 can also be made larger, so that the strength of the cylindrical part 11 is also larger.

[0072] In some examples, as Figure 2 shown, the height of the nozzle 7 of the polysilicon reduction furnace is w, and the height of the cylindrical part 11 is w2.

[0073] As Figure 2 shown, at this time, the height of the conical part 2 is w1.

[0074] Exemplarily, the value of or etc.

[0075] Exemplarily, the height w of the nozzle 7 of the polysilicon reduction furnace satisfies 55 mm ≤ w ≤ 100 mm, and 10 mm ≤ w2 ≤ 30 mm.

[0076] For example, the height w of the nozzle 7 of the polysilicon reduction furnace can be 55 mm, 80 mm or 100 mm, etc., and the height w2 of the cylindrical part 11 can be 10 mm, 20 mm or 30 mm, etc.

[0077] Through the above settings, there is sufficient space in the vertical direction inside the nozzle 7 of the polysilicon reduction furnace to arrange the elliptical flow channel section 4, the transition section and the rectifying section 6.

[0078] In some embodiments, as Figure 2 shown, the upper end surface of the conical part 2 is an arc surface, and the outer wall surface of the conical part 2 is connected to the inner wall surface of the rectifying section 6 through the arc surface.

[0079] Through the above settings, the upper end surface of the conical part 2 can be made smoother, reducing the stress concentration problem at the end of the nozzle 7 of the polysilicon reduction furnace, improving the strength of the end of the nozzle 7 of the polysilicon reduction furnace, and preventing impurities from adhering to the upper end surface of the nozzle 7 of the polysilicon reduction furnace.

[0080] In some embodiments, anti-corrosion coatings with infrared reflection functions are coated on the outer wall surfaces of both the conical part 2 and the cylindrical part 11.

[0081] The manufacturing method of the anti-corrosion coating can include the following two methods:

[0082] The first method: First, perform surface treatment on the outside of the nozzle 7 of the polysilicon reduction furnace. Use white corundum sand with a particle size between 0.15 mm and 0.60 mm to perform sandblasting on its surface to increase its surface roughness and improve the coating adhesion. Then, use a 35% hydrochloric acid solution to pickle its surface to remove the oxide layer and grease. After that, adopt the supersonic spraying method to collide semi-molten granular materials (corrosion-resistant and high-reflection materials such as Hastelloy, high-entropy alloy, or titanium nitride ceramic powder) at high speed on the outer wall surface of the nozzle to form a dense anti-corrosion coating resistant to high-temperature chlorine corrosion.

[0083] The second method: Different from the first method, the formation method of the coating in this method uses the sol-gel method. Use nanoscale spherical high-purity SiO2 to make silica sol, evenly coat the silica sol on the outer surface of the nozzle 7 of the polysilicon reduction furnace that has been sandblasted and pickled, and then let it stand and dry. After that, perform solidification heat treatment on the coating in a nitrogen atmosphere at 300°C - 500°C, and finally form a dense SiO2 coating on the surface of the nozzle 7 of the polysilicon reduction furnace.

[0084] The anti-corrosion coating with infrared reflection function has a high infrared reflectivity or low thermal conductivity, which can reduce the thermal radiation energy received on the surface of the nozzle 7 of the polysilicon reduction furnace and lower the heat conduction rate, thereby protecting the nozzle 7 of the polysilicon reduction furnace and preventing the temperature of the nozzle 7 of the polysilicon reduction furnace from being too high. In addition, the high density and corrosion resistance of the anti-corrosion coating isolate the high-chlorine environment in the furnace from the metal material matrix of the nozzle 7 of the polysilicon reduction furnace, blocking the contact between the metal material matrix and hydrogen chloride from the source, reducing the release of metal impurities, and improving the purity of the silicon rod.

[0085] In some embodiments, in combination Figure 3 、 Figure 4 and Figure 5 , a side flow channel 5 is provided on the side wall of the conical part 2 for leading out part of the gas in the inner hole to the outside of the nozzle 7 of the polysilicon reduction furnace. In the direction from inside to outside, the side flow channel 5 extends obliquely upward and penetrates the side wall of the conical part 2. The starting point of the side flow channel 5 corresponds to the upper-middle position of the elliptical flow channel section 4, and the end point of the side flow channel 5 corresponds to the lower part of the conical part 2.

[0086] The starting point of the side flow channel 5 corresponds to the position in the upper middle part of the elliptical flow channel section 4, which can make the initial flow velocity of the gas entering the side flow channel 5 relatively high.

[0087] Compared with the reaction temperature in the polysilicon reduction furnace, the temperature of the gas in the elliptical flow channel section 4 is relatively low. Through the above settings, a part of the gas in the elliptical flow channel section 4 can be led out to the outside of the nozzle 7 of the polysilicon reduction furnace. Utilizing the Coanda wall attachment effect, the conical part 2 is cooled under the scouring of the high-speed gas attached to the wall, avoiding the corrosion of the top of the conical part 2 due to high temperature. At the same time, the gas ejected through the side flow channel 5 can drive the flow of the gas at the bottom of the reduction furnace, promoting the renewal and replenishment of the materials at the root of the silicon rod and heat exchange, and avoiding the occurrence of thin rods and silicon cores radiating at the root.

[0088] In some embodiments, the number of the side flow channels 5 is n, and the n side flow channels 5 are sequentially arranged at the same height of the conical part 2 at intervals and are evenly distributed around the axis of the conical part 2. Where n is a positive integer, and 2 ≤ n ≤ 8.

[0089] Exemplarily, the number of the side flow channels 5 can be two, four or eight.

[0090] Through the above settings, the gas ejected from the multiple side flow channels 5 can be evenly distributed outside the nozzle 7 of the polysilicon reduction furnace, avoiding the influence of uneven gas flow on the stability of the feed flow field and temperature field at the bottom of the reduction furnace.

[0091] In some embodiments, in combination with Figure 3 and Figure 4 , along the gas flow direction, the side flow channel 5 includes a first straight segment, a first arc segment, a second straight segment, a second arc segment and a third straight segment that are sequentially connected. The center line of the first arc segment is tangent to the center lines of the first straight segment and the second straight segment respectively, and the center line of the second arc segment is tangent to the center lines of the second straight segment and the third straight segment respectively.

[0092] Exemplarily, as Figure 5 shown, the cross-section of the side flow channel 5 is a rounded arc shape, and the side flow channel 5 can be obtained by milling the rounded arc shape along the center lines of the first straight segment, the first arc segment, the second straight segment, the second arc segment and the third straight segment in sequence.

[0093] Through the above settings, the connection between each part of the side flow channel 5 can be made smoother, reducing the resistance when the gas flows in the side flow channel 5.

[0094] In some examples, in combination with Figure 3 and Figure 4 , the included angle between the center line of the first straight segment and the vertical direction is A3, and 0° ≤ A3 ≤ 8°.

[0095] Exemplarily, the included angle A3 between the center line of the first straight line segment and the vertical direction can be 0°, 4°, 8°, etc.

[0096] This can make the change amount of the flow direction of the gas when entering the first straight line segment from the elliptical flow channel segment 4 smaller, so as to reduce the resistance when the gas enters the first straight line segment.

[0097] In some examples, in combination with Figure 3 and Figure 4 , the included angle between the center line of the second straight line segment and the horizontal direction is A2, and 30° ≤ A2 ≤ 60°.

[0098] Exemplarily, the included angle A2 between the center line of the second straight line segment and the horizontal direction can be 30°, 45°, 60°, etc.

[0099] In some examples, in combination with Figure 3 and Figure 4 , the included angle between the center line of the third straight line segment and the outer wall surface of the conical part 2 is A1, and 15° ≤ A1 ≤ 25°.

[0100] Exemplarily, the included angle A1 between the center line of the third straight line segment and the outer wall surface of the conical part 2 can be 15°, 20°, 25°, etc.

[0101] Through the above settings, the resistance of the gas flowing in the side flow channel 5 can be reduced, and finally the gas is ejected in an obliquely upward direction.

[0102] In some embodiments, in the radial direction of the polysilicon reduction furnace nozzle 7, the width of the side flow channel 5 is k, and 0.5 mm ≤ k ≤ 3 mm.

[0103] Exemplarily, the width k of the side flow channel 5 can be 0.5 mm, 1.5 mm, 3 mm, etc.

[0104] It can be understood that the larger the width k of the side flow channel 5, the more gas flows out of each side flow channel 5, the more cold energy the gas carries, and the better the cooling effect on the upper part of the polysilicon reduction furnace nozzle 7; the smaller the width k of the side flow channel 5, the less gas flows out of each side flow channel 5, but the flow velocity of the gas after flowing out of each side flow channel 5 will be larger.

[0105] Through the above settings, the gas volume and flow velocity of the gas flowing out of the side flow channel 5 can meet the requirements for cooling the upper part of the polysilicon reduction furnace nozzle 7.

[0106] In some embodiments, in combination with Figure 1 and Figure 2 , the longitudinal cross-sectional shape of the transition section is arc-shaped, the lower end of the longitudinal cross-section of the transition section is tangent to the upper end of the longitudinal cross-section of the elliptical flow channel segment 4, and the upper end of the longitudinal cross-section of the transition section is tangent to the lower end of the longitudinal cross-section of the rectifying section 6.

[0107] Through the above settings, the gas can flow smoothly through the connection positions of the elliptical flow channel section 4 and the transition section, and the gas can flow smoothly through the connection positions of the rectifying section 6 and the transition section, avoiding the generation of eddy currents at the above connection positions and increasing the resistance during gas flow.

[0108] The inventor of the present utility model simulated the implementation effects of different polysilicon reduction furnace nozzles 7 in this embodiment. During the simulation process, two experimental groups and a control group A were adopted. The control group A is a cylindrical nozzle in the prior art, and the inner flow channel is also cylindrical. The two experimental groups are the polysilicon reduction furnace nozzle B and the polysilicon reduction furnace nozzle C respectively. Among them, the inner hole of the polysilicon reduction furnace nozzle B includes an elliptical flow channel section 4, a transition section, and a rectifying section 6 that are connected in sequence, and the polysilicon reduction furnace nozzle B includes a conical part 2 and a cylindrical part 11; the polysilicon reduction furnace nozzle C adds four side flow channels 5 on the basis of the polysilicon reduction furnace nozzle B, and the width of the side flow channel 5 is 1 mm.

[0109] During the simulation process, the feed flow rate was set to 0.11 kg / s, the components of the feed gas were hydrogen and trichlorosilane, the molar ratio of hydrogen to trichlorosilane was 4:1, and the nozzle diameter was set to 12 mm.

[0110] The simulation results are shown in Figure 6 , Figure 6 The upper half of the three pictures in which correspond to the outer surface temperature of the polysilicon reduction furnace nozzle, Figure 6 The lower half of the three pictures in which correspond to the cross-sectional temperature of the polysilicon reduction furnace nozzle. As can be seen from Figure 6 , the temperature of the nozzle in the control group A is uneven, and overheating occurs in the top area, which is consistent with the result that the top of the nozzle in the prior art is prone to corrosion in actual production; the overall temperature uniformity in the polysilicon reduction furnace nozzle B is improved, and the highest temperature is lower than that in the control group A; the overall temperature in the polysilicon reduction furnace nozzle C is lower than that in the control group A and the polysilicon reduction furnace nozzle B, and the temperature drop of its conical part 2 is obvious. Therefore, the problem that the surface temperature of the polysilicon reduction furnace nozzle C is too high and prone to corrosion can be effectively avoided.

[0111] From the above experimental results, it can be seen that the structures of the elliptical flow channel section 4, the transition section, the rectifying section 6, the conical part 2, and the side flow channel 5 provided in the polysilicon reduction furnace nozzle 7 can have a beneficial effect on reducing the temperature of the polysilicon reduction furnace nozzle 7.

[0112] Embodiment 2:

[0113] As Figure 7As shown, the embodiment of the utility model further provides a polysilicon reduction furnace for producing silicon rods, the polysilicon reduction furnace comprising a furnace body and the polysilicon reduction furnace nozzle 7 in embodiment 1. The bottom of the furnace body has a chassis 8, and the chassis 8 has a plurality of air inlet branches 10. The polysilicon reduction furnace nozzle 7 is fixed on the chassis 8.

[0114] Exemplarily, the bottom plate 8 is used to fix the polysilicon reduction furnace nozzle 7. The air intake branch pipe 10 is used to transport the raw material gas.

[0115] Exemplarily, a water cooling chamber 9 is disposed in the chassis 8 , and the water cooling chamber 9 can cool the chassis 8 and the nozzle 7 of the polysilicon reduction furnace disposed thereon.

[0116] Through the above arrangement, the height of the gas ejected from the nozzle 7 of the polysilicon reduction furnace is relatively high, which can improve the problem of uneven temperature field and flow field in the polysilicon reduction furnace, thereby improving the problem of high temperature at the top of the silicon rod, reducing the occurrence of adverse phenomena such as silicon core radiation and big-headed rods, and improving the quality of the silicon rods.

[0117] In some examples, such as Figure 1 As shown, the bottom of the polysilicon reduction furnace nozzle 7 extends outward to form a mounting portion 1, and an external thread is provided on the outer side of the mounting portion 1. The polysilicon reduction furnace nozzle 7 is fixed to the chassis 8 through the external thread on the mounting portion 1. A through hole is opened in the mounting portion 1, and the air intake branch pipe 10 is connected to the inner hole of the polysilicon reduction furnace nozzle 7 through the through hole.

[0118] The inner diameter of the air intake branch pipe 10 , the inner diameter of the through hole, and the inner diameter at the entrance of the elliptical flow channel section 4 are all the same to reduce the pressure drop loss when the gas enters the inner hole of the polysilicon reduction furnace nozzle 7 from the air intake branch pipe 10 .

[0119] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A polysilicon reduction furnace nozzle, characterized in that: The polysilicon reduction furnace nozzle has an inner hole, and the inner hole includes an elliptical flow channel section (4), a transition section, and a rectifying section (6) which are connected in sequence; the aperture of the inner hole from the elliptical flow channel section (4) to the transition section gradually decreases, and the aperture at the top of the transition section is the same as the aperture at the bottom of the rectifying section (6); The longitudinal cross-section of the elliptical flow channel section (4) is in the shape of a semi-ellipse; and the shape of the rectifying section (6) is in the shape of a cylinder.

2. The polysilicon reduction furnace nozzle according to claim 1, characterized in that: In the elliptical flow channel section (4), the length of the short axis of the ellipse is D2, and half the length of the long axis of the ellipse is L2.

3. The polysilicon reduction furnace nozzle according to claim 2, characterized in that: In the rectifying section (6), the diameter of the cylinder is D1, and / or, The height of the transition section is less than or equal to 4. The polysilicon reduction furnace nozzle according to claim 1, characterized in that: The polysilicon reduction furnace nozzle comprises a conical portion (2) and a cylindrical portion (11), the lower portion of the conical portion (2) is connected to the cylindrical portion (11), the elliptical flow channel section (4) is located inside the cylindrical portion (11) and extends to the inside of the conical portion (2), and the transition section and the straightening section (6) are both located inside the conical portion (2).

5. The polysilicon reduction furnace nozzle according to claim 4, characterized in that: The cone angle of the cone portion (2) is α, 10°≤α≤15°; and / or, The outer diameter of the cylindrical portion (11) is D3, 35 mm ≤ D3 ≤ 55 mm; and / or, The height of the polysilicon reduction furnace nozzle is w, the height of the cylindrical portion (11) is w2, 6. The polysilicon reduction furnace nozzle according to claim 4, characterized in that: The upper end surface of the conical portion (2) is an arc surface, and the outer wall surface of the conical portion (2) is connected to the inner wall surface of the rectifying section (6) via the arc surface.

7. The polysilicon reduction furnace nozzle according to claim 4, characterized in that: The outer wall surfaces of the conical portion (2) and the cylindrical portion (11) are both coated with an anti-corrosion coating having an infrared reflection function.

8. The polysilicon reduction furnace nozzle according to claim 4, characterized in that: A side flow channel (5) is provided on the side wall of the conical portion (2) for guiding part of the gas in the inner hole to the outside of the nozzle of the polysilicon reduction furnace; In the direction from inside to outside, the side flow channel (5) extends obliquely upward and passes through the side wall of the conical portion (2), the starting point of the side flow channel (5) corresponds to the position of the upper part of the elliptical flow channel section (4), and the end point of the side flow channel (5) corresponds to the position of the lower part of the conical portion (2).

9. The polysilicon reduction furnace nozzle according to claim 8, characterized in that: The number of the side flow channels (5) is n, and the n side flow channels (5) are sequentially arranged at intervals at the same height of the conical portion (2) and are evenly distributed around the axis of the conical portion (2); Wherein n is a positive integer, and 2≤n≤8.

10. The polysilicon reduction furnace nozzle according to claim 8, characterized in that: Along the flow direction of the gas, the side flow channel (5) comprises a first straight line segment, a first arc segment, a second straight line segment, a second arc segment and a third straight line segment which are connected in sequence, the center line of the first arc segment is tangent to the center line of the first straight line segment and the center line of the second straight line segment respectively, and the center line of the second arc segment is tangent to the center line of the second straight line segment and the center line of the third straight line segment respectively; Wherein, the angle between the center line of the first straight line segment and the vertical direction is A3, 0°≤A3≤8°; and / or, The included angle between the center line of the second straight line segment and the horizontal direction is A2, 30°≤A2≤60°; and / or, The included angle between the center line of the third straight line segment and the outer wall surface of the conical portion (2) is A1, and 15°≤A1≤25°.

11. The polysilicon reduction furnace nozzle according to claim 8, characterized in that: In the radial direction of the nozzle of the polysilicon reduction furnace, the width of the side flow channel (5) is k, and 0.5mm≤k≤3mm.

12. The polysilicon reduction furnace nozzle according to any one of claims 1 to 11, characterized in that: The shape of the longitudinal section of the transition section is an arc, the lower end of the longitudinal section of the transition section is tangent to the upper end of the longitudinal section of the elliptical flow channel section (4), and the upper end of the longitudinal section of the transition section is tangent to the lower end of the longitudinal section of the straightening section (6).

13. A polysilicon reduction furnace, characterized in that: include: A furnace body, the bottom of which is provided with a bottom plate (8), wherein the bottom plate (8) is provided with a plurality of air intake branch pipes (10); and, The polysilicon reduction furnace nozzle according to any one of claims 1 to 12; the polysilicon reduction furnace nozzle is fixed on the chassis (8).

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