Pyrolytic boron nitride reacting furnace and use method thereof

Abstract

The invention relates to a pyrolytic boron nitride reaction furnace and a use method, the pyrolytic boron nitride reaction furnace comprises a controller, an evaporation chamber, an objective table, separation layers, an air inlet pipe, a laser, a multi-stage buffer cavity and a reaction chamber, the objective table in sliding connection is arranged in the evaporation chamber and used for containing boron oxide, and the inner wall of the evaporation chamber is fixedly connected with a first separation layer and a second separation layer; the gas inlet pipe of the spiral structure is tangent to the evaporation chamber and used for introducing nitrogen and hydrogen, the laser is fixed to the evaporation chamber and used for heating boron oxide, the multi-stage buffer cavity is sequentially connected to the top end of the evaporation chamber and the spherical reaction chamber, and the balance rod mechanism ensures that boron oxide is always kept at the optimal heating position. The molecular sieve membrane separation system can effectively remove moisture and carbon monoxide, the invention also comprises a detailed use method which covers the whole process from a preparation stage to continuous operation, and the design realizes efficient and accurate reaction environment control, intelligent raw material supply and impurity separation.

Description

Technical Field

[0001] The invention relates to a pyrolytic boron nitride reactor and a use method thereof, and in particular to a pyrolytic boron nitride reactor and a use method thereof applied in the technical field of boron nitride preparation. Background Art

[0002] Boron nitride is an important high-temperature ceramic material with excellent thermal stability, chemical inertness and electrical insulation properties. It is widely used in aerospace, electronics, metallurgy and other fields. Traditional boron nitride preparation methods mainly include vapor deposition and pyrolysis. However, these methods still have some problems in production efficiency, product quality consistency and raw material utilization.

[0003] In recent years, the use of boron oxide (B2O3) instead of boron trichloride (BCl3) as a boron source for pyrolytic boron nitride has attracted widespread attention. This method has the advantages of low raw material cost and high operational safety. However, the use of B2O3 as a precursor also brings new challenges, such as how to effectively control the evaporation and transportation of B2O3 and how to reduce the impact of oxygen impurities on the final product.

[0004] Chinese invention patent CN102796995B discloses a vapor deposition furnace and method for preparing pyrolytic boron nitride products. The innovation lies in the furnace design and insulation system. The design effectively suppresses short-term temperature rise through a phase change insulation layer, thereby improving the insulation effect. However, the method still has room for improvement in terms of the continuity of raw material supply and the purity control of the reaction gas, especially when using B2O3 as a precursor, and cannot effectively solve the oxygen pollution problem.

[0005] Chinese invention patent CN102330068B proposes a method for preparing pyrolytic boron nitride sheets and a vapor deposition furnace, which is characterized by using a rotating tilting mold to improve the surface quality of the product. This design does improve the surface flatness and pass rate of the product, but there is still room for improvement in the precise control of the reaction temperature and the uniformity of the raw gas mixing. In addition, this method is mainly for the case where BCl3 is the boron source and is not suitable for the B2O3 precursor system.

[0006] The above designs have improved the production efficiency and quality of boron nitride to a certain extent by improving the furnace structure and process parameters, but there are still certain limitations, such as low raw material utilization, insufficient control accuracy of reaction conditions, and difficulty in achieving continuous production. In addition, these methods also need to be improved in terms of energy efficiency and environmental friendliness. Especially when using B2O3 as a boron source, the existing technology still has certain limitations in solving problems such as oxygen pollution, B2O3 vapor concentration control, and treatment of by-products (such as water and carbon monoxide). Summary of the invention

[0007] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is how to solve the problems of oxygen pollution, B2O3 vapor concentration control, and treatment of by-products (such as water and carbon monoxide) when using B2O3 as a boron source.

[0008] To solve the above problems, the present invention provides a pyrolytic boron nitride reactor and a method for using the same, including a controller and an evaporation chamber, wherein a loading platform is slidably connected to the evaporation chamber, a separation layer 1 and a separation layer 2 are fixedly connected to the inner wall of the evaporation chamber, an air inlet pipe is fixedly connected to the outer end of the evaporation chamber, one end of the air inlet pipe penetrates the separation layer 1 and is connected to the inner wall of the separation layer 1, and the other end is connected to an external air supply system, the air inlet pipe is arranged tangent to the evaporation chamber, the air inlet pipe is used to introduce nitrogen and hydrogen, a laser is fixedly connected to the evaporation chamber, a buffer chamber 1, a buffer chamber 2, a buffer chamber 3 and a reaction chamber are fixedly connected in sequence to the top of the evaporation chamber, the laser, the buffer chamber 1, the buffer chamber 2, the buffer chamber 3 and the reaction chamber are all electrically connected to the controller, and the loading platform is used to hold boron oxide.

[0009] As a further improvement of the present application, a moisture collection chamber and a carbon monoxide collection chamber are respectively formed between the separation layer 1 and the separation layer 2 and the inner wall of the evaporation chamber, and the moisture collection chamber and the carbon monoxide collection chamber are both connected to the external system through pipelines.

[0010] As a further improvement of the present application, separation layer one and separation layer two are respectively made of multi-layer SOD molecular sieve membrane and multi-layer NaA (LTA) molecular sieve membrane, the SOD molecular sieve membrane is used to separate water, and the NaA (LTA) molecular sieve membrane is used to separate carbon monoxide.

[0011] As a further improvement of the present application, a heat insulation layer is fixedly connected to the outer wall of the evaporator chamber, a preheating coil is fixedly connected to the outer end of the air inlet pipe, and the preheating coil is electrically connected to the controller.

[0012] As another improvement of the present application, buffer chamber one, buffer chamber two and buffer chamber three all include an inner tube, a coil is fixedly connected to the outer wall of the inner tube, the outer wall of the coil is fixedly connected to the insulation layer, an electromagnetic valve is fixedly connected to the inner tube, and the coil and the electromagnetic valve are both electrically connected to the controller.

[0013] As another improved supplement of the present application, the reaction chamber includes a spherical reaction chamber, and an ammonia pipe is fixedly connected to the outer wall of the spherical reaction chamber, the ammonia pipe is arranged tangent to the spherical reaction chamber, a discharge pipe is fixedly connected to the top of the spherical reaction chamber, the discharge pipe is connected to the deposition chamber, a heating coil is wrapped around the outer wall of the reaction chamber, and the heating coil is electrically connected to the controller.

[0014] As another improved supplement of the present application, the air inlet pipe is a spiral structure, the bottom end of the evaporation chamber is fixedly connected to a base, and a balance rod is rotatably connected to the base.

[0015] As another improvement of the present application, one end of the balance pole is rotatably connected to the bottom end of the loading platform, and the other end of the balance pole is rotatably connected to a counterweight.

[0016] A method for using a pyrolytic boron nitride reactor comprises the following steps:

[0017] S1, preparation stage: Place the boron oxide on the stage, adjust the position of the boron oxide by balancing the rod and the counterweight to make it in the best heating position of the laser, start the controller, and start the system preheating;

[0018] S2. Gas input and premixing: nitrogen and hydrogen are input through the spiral intake pipe. The spiral structure promotes the full mixing of nitrogen and hydrogen. The mixed gas is heated by the preheating coil outside the intake pipe. The intake pipe is tangent to the evaporation chamber to ensure that the preheated and mixed gas can fully mix and react with the B2O3 gas.

[0019] S3, boron oxide evaporation: the laser starts to heat the boron oxide on the stage. As the boron oxide is consumed, the counterweight of the balance bar moves down, causing the remaining boron oxide to move up and remain in the optimal heating position. The boron oxide evaporates to form gaseous B2O3, which is fully mixed with the preheated nitrogen and hydrogen mixture in the evaporation chamber.

[0020] S4, water separation: the mixed gas passes through the separation layer 1 (SOD molecular sieve membrane), the water molecules are separated and collected in the water collection chamber, and then discharged through the pipeline;

[0021] S5. Carbon monoxide separation: The gas continues to pass through the separation layer 2 (NaA (LTA) molecular sieve membrane), the carbon monoxide is separated and collected in the carbon monoxide collection chamber, and then discharged through the pipeline.

[0022] S6, buffer process: the purified gas enters buffer chamber 1, buffer chamber 2 and buffer chamber 3 in turn. The inner tube of each buffer chamber is heated by a coil. The solenoid valve controls the gas flow to ensure a stable gas supply. The buffer chamber system smoothes the fluctuation of gas concentration and flow.

[0023] S7, reaction process: a stable gas mixture enters the spherical reaction chamber (reaction chamber), the outer wall of the reaction chamber is wrapped with a heating coil to heat the reaction chamber to ensure the stability of the reaction temperature, ammonia is input through a tangentially arranged ammonia pipe and fully mixed with B2O3 gas, and under high temperature conditions, B2O3 and NH3 react to generate boron nitride;

[0024] S8, product output: the reaction product is transported to the deposition chamber through the discharge pipe, where the boron nitride is deposited to form a film or powder;

[0025] S9. Continuous operation: During the whole process, the controller continuously monitors and adjusts the temperature, pressure and gas flow of each part. The thermal insulation layer ensures the temperature stability of the whole system. The balance bar mechanism ensures that the boron oxide always remains in the optimal heating position to achieve continuous and stable raw material supply.

[0026] In summary, this application has the following beneficial effects:

[0027] 1. Efficient and accurate reaction environment control. The spiral air inlet pipe design combined with the laser heating system and multi-point temperature control device realizes efficient preheating, mixing and precise temperature control of the gas. The spherical reaction chamber and tangential ammonia injection optimize the reaction conditions. The multi-stage buffer chamber and solenoid valve system ensure the stability of gas concentration and flow. These designs together create a highly controllable reaction environment and significantly improve the conversion rate, product quality and production efficiency of boron nitride.

[0028] 2. Intelligent raw material supply and impurity separation. The balance bar and counterweight mechanism realize automatic adjustment of the boron oxide position to ensure that the raw material is always in the optimal heating position. The multi-stage separation system composed of SOD and NaA (LTA) molecular sieve membranes effectively removes impurities such as moisture and carbon monoxide. This intelligent design not only improves the automation level of the system, but also ensures the high purity of the reaction gas, thereby improving the consistency and stability of product quality.

[0029] 3. All-round automated management system. The highly integrated control system realizes real-time monitoring and adjustment of parameters such as temperature, pressure, and gas flow. The modular design facilitates maintenance and upgrading, which not only improves the controllability and repeatability of the production process, but also reduces human operation errors and improves overall production efficiency and safety. At the same time, the system's data collection function provides reliable support for process optimization and is conducive to long-term technological improvement.

[0030] 4. Energy and resource utilization. The efficient insulation design and thermal management system significantly reduce heat loss and improve energy utilization efficiency. The effective separation and collection of by-products (such as water and carbon monoxide) not only improves the purity of the main product, but also creates conditions for the potential utilization of by-products. This design reduces production costs, improves resource utilization, and makes the entire production process more economical and environmentally friendly.

[0031] 5. Strong adaptability to industrial production capacity. The system design allows continuous and stable production, which is particularly suitable for large-scale and long-term industrial applications. It can produce boron nitride films or powders and has good market adaptability. The highly automated and safe design reduces operational risks and improves production reliability. These characteristics enable the equipment to improve product quality while also being able to cope with different market demands and large-scale production, providing strong technical support for the industrial application of boron nitride. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the overall structure diagram of this application;

[0033] Figure 2 This is an overall exploded view of this application;

[0034] Figure 3 Partial explosion for this application Figure 1 ;

[0035] Figure 4 Partial explosion for this application Figure 2 ;

[0036] Figure 5 Partial explosion for this application Figure 3 ;

[0037] Figure 6 This is the front view of the application;

[0038] Figure 7 For this application Figure 6 Middle AA section view;

[0039] Figure 8 For this application Figure 7 Middle BB section view;

[0040] Fig. 9 For this application Figure 7 Middle CC section view;

[0041] Fig.10 For this application Figure 7 Middle DD section view;

[0042] Fig.11 For this application Figure 7 Middle EE section view;

[0043] Fig.12 This is the appearance structure diagram of this application.

[0044] Description of the numbers in the figure:

[0045] 1. Evaporation chamber; 2. Stage; 3. Separation layer 1; 4. Separation layer 2; 5. Inlet pipe; 6. Laser; 7. Buffer chamber 1; 8. Buffer chamber 2; 9. Buffer chamber 3; 10. Reaction chamber; 11. Insulation layer; 12. Preheating coil; 13. Inner tube; 14. Coil; 15. Solenoid valve; 16. Ammonia pipe; 17. Discharge pipe; 18. Balance bar. DETAILED DESCRIPTION

[0046] Four embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0047] Example 1

[0048] like Figures 1 to 12 As shown, the pyrolytic boron nitride reactor of this embodiment mainly includes: an evaporation chamber 1 made of high-temperature resistant alloy material and in a cylindrical shape; flange connection ports are provided at the top and bottom of the evaporation chamber 1 for easy connection and maintenance with other components.

[0049] The stage 2 is made of high-purity graphite material and is slidably connected to the inner wall of the evaporation chamber 1 through a high-precision slide rail. The slide rail is made of high-temperature resistant ceramic material to ensure that it can maintain good sliding performance in a high-temperature environment.

[0050] Separation layer 1 3 and separation layer 2 4 are fixedly connected to the inner wall of evaporation chamber 1, 10 cm and 20 cm away from the bottom of evaporation chamber 1, respectively. Separation layer 1 3 is made of multi-layer SOD molecular sieve membrane with a total thickness of 2 mm; separation layer 2 4 is made of multi-layer NaA (LTA) molecular sieve membrane with a total thickness of 3 mm. Both separation layers are connected to the inner wall of evaporation chamber 1 by special high-temperature sealing technology to ensure airtightness.

[0051] The air inlet pipe 5 is made of 316L stainless steel and is spirally wound on the outer wall of the evaporation chamber 1. One end of the air inlet pipe 5 passes through the separation layer 3 and is connected to the inner wall of the separation layer 3. The other end is connected to the external gas supply system through a high-pressure joint. The air inlet pipe 5 is arranged tangent to the evaporation chamber 1, and the inlet angle is 30 degrees to optimize the gas mixing effect.

[0052] The laser 6 is a 500W CO2 laser with a wavelength of 10.6 μm, which is fixedly connected to the evaporation chamber 1 through a special quartz window. The laser 6 is equipped with a precise focusing system that can focus the laser beam to a spot with a diameter of 2 mm.

[0053] The buffer chamber 1 7 , the buffer chamber 2 8 , and the buffer chamber 3 9 are all made of 316L stainless steel. The three buffer chambers are fixedly connected to the top of the evaporation chamber 1 in sequence and connected through high-temperature flanges and metal sealing rings.

[0054] The reaction chamber 10 is made of high-purity boron nitride material and is spherical. The reaction chamber 10 is connected to the buffer chamber 3 9 through a high-temperature flange.

[0055] The controller adopts an industrial-grade PLC system and is equipped with high-precision temperature, pressure and flow sensors to achieve precise control of the entire system. The controller is electrically connected to the laser 6, buffer cavity 1 7, buffer cavity 2 8, buffer cavity 3 9 and reaction chamber 10 through anti-interference shielded cables.

[0056] The heat insulating layer 11 is made of multi-layer ceramic fiber material, with a thickness of 5 cm, and is fixedly connected to the outer wall of the evaporation chamber 1. The thermal conductivity of the heat insulating layer 11 is less than 0.05 W / (m·K), which effectively reduces heat loss.

[0057] The preheating coil 12 is made of nickel-chromium alloy wire, wound around the outer end of the intake pipe 5, with a power of 1 kW. The preheating coil 12 is electrically connected to the controller through an anti-interference shielded cable.

[0058] Working process:

[0059] When the system is started, the controller starts the preheating procedure, and the preheating coil 12 heats the intake pipe 5 to preheat the incoming nitrogen and hydrogen to 300°C.

[0060] The laser 6 starts to heat the boron oxide on the stage 2, and the temperature is controlled between 1000-1200° C. The boron oxide evaporates to form gaseous B2O3.

[0061] The preheated nitrogen and hydrogen enter the evaporation chamber 1 through the air inlet pipe 5 and are fully mixed with the gaseous B2O3.

[0062] The mixed gas first passes through the separation layer 3 (SOD molecular sieve membrane), and the water molecules are separated and collected in the moisture collection chamber.

[0063] The gas continues to pass through separation layer 2 4 (NaA (LTA) molecular sieve membrane), and carbon monoxide is separated and collected in the carbon monoxide collection chamber.

[0064] The purified gas enters buffer chamber 1 7, buffer chamber 2 8 and buffer chamber 3 9 in sequence to stabilize the gas concentration and flow rate.

[0065] Finally, the stabilized gas enters the reaction chamber 10 and reacts with the ammonia gas to generate boron nitride.

[0066] The laser heating system can accurately control the evaporation temperature of boron oxide and improve the purity and concentration stability of B2O3 gas.

[0067] The spiral inlet pipe 5 and the tangential inlet design significantly improve the gas mixing efficiency, ensuring that B2O3 is fully mixed with nitrogen and hydrogen.

[0068] The multi-layer molecular sieve membrane separation system effectively removes moisture and carbon monoxide, greatly improving the purity of the reaction gas.

[0069] The three-level buffer chamber design effectively smooths fluctuations in gas concentration and flow, providing a stable gas environment for subsequent reactions.

[0070] The design of the heat insulation layer 11 and the preheating coil 12 significantly improves the energy efficiency of the system and reduces heat loss.

[0071] The overall modular design facilitates maintenance and upgrading, and improves the service life and adaptability of the equipment.

[0072] The highly integrated control system achieves precise control of the entire process and improves the consistency and repeatability of product quality.

[0073] This embodiment improves the production efficiency and product quality of pyrolytic boron nitride, and provides reliable technical support for the large-scale production of high-quality boron nitride.

[0074] Example 2

[0075] like Figures 1 to 12 As shown, based on Example 1, this example focuses on the detailed design of the buffer chamber and the reaction chamber:

[0076] Each of the buffer chambers 1 7 , 2 8 and 3 9 is made of 316L stainless steel, and each buffer chamber contains the following components: the inner tube 13 is made of high-purity quartz glass, and the inner tube 13 is connected to the buffer chamber body through a special high-temperature sealing ring to ensure air tightness.

[0077] The coil 14 is made of nickel-chromium alloy wire and is wound around the outer wall of the inner tube 13. The total length of the coil 14 is 5 m and the power is 2 kW. The inner tube 13 can be heated to 1500°C.

[0078] The solenoid valve 15 is made of high temperature alloy material and is installed at the air inlet end of the inner tube 13. The response time of the solenoid valve 15 is less than 10ms, and the gas flow rate can be accurately controlled.

[0079] The heat insulation layer 11 is made of multi-layer ceramic fiber material with a thickness of 3 cm, and is wrapped around the outside of the coil 14. The thermal conductivity of the heat insulation layer 11 is less than 0.05 W / (m·K), which effectively reduces heat loss.

[0080] The spherical reaction cavity of the reaction chamber 10 is made of high-purity boron nitride material, and the spherical design can ensure that the gas is evenly mixed and reacted in the cavity.

[0081] The ammonia pipe 16 is made of corrosion-resistant Hastelloy C-276 material. The ammonia pipe 16 is tangent to the spherical reaction chamber, and the cutting angle is 30 degrees to optimize the injection effect of the ammonia.

[0082] The discharge pipe 17 is made of high-purity boron nitride material. The discharge pipe 17 is fixedly connected to the top of the spherical reaction chamber and is connected to the deposition chamber through a high-temperature flange.

[0083] The heating coil is made of tantalum wire and is evenly wound on the outer wall of the reaction chamber 10. The total length of the heating coil is 10m and the power is 5kW, which can heat the reaction chamber 10 to 1600°C.

[0084] The control system adopts a distributed control system (DCS), including multiple high-precision temperature sensors, pressure sensors and gas flow meters. The control system is electrically connected to each component through anti-interference shielded cables to achieve precise temperature, pressure and flow control.

[0085] Working process:

[0086] After the gas enters the buffer chamber 7, it is first precisely controlled by the solenoid valve 15, and the gas in the inner tube 13 is heated to a preset temperature (usually 1000-1200°C) by the coil 14.

[0087] The heated gas enters buffer chamber 2 8 and buffer chamber 3 9 in sequence, and each buffer chamber repeats a similar heating and flow control process. This multi-stage buffer design can effectively smooth fluctuations in gas concentration and temperature.

[0088] The stabilized gas enters the spherical reaction chamber (reaction chamber 10), and at the same time, preheated ammonia is injected tangentially through the ammonia pipe 16. The spherical design ensures that the gas is fully mixed.

[0089] The heating coil on the outer wall of the reaction chamber 10 maintains the temperature at an ideal reaction temperature (usually 1400-1600° C.), at which temperature B2O3 and NH3 react to generate boron nitride.

[0090] The reaction product is transported through the discharge pipe 17 to the deposition chamber, where the boron nitride is deposited in the form of a thin film or powder.

[0091] During the entire process, the control system continuously monitors and adjusts the temperature, pressure and gas flow of each part to ensure the stability of the reaction conditions.

[0092] The multi-stage buffer chamber design significantly improves the stability of gas temperature and concentration, creating ideal conditions for the synthesis of high-quality boron nitride.

[0093] The combination of inner tube 13 and coil 14 enables precise temperature control, which helps to optimize reaction kinetics.

[0094] The rapid response characteristics of the solenoid valve 15 enable the system to adjust the gas flow in real time, thereby improving the controllability of the process.

[0095] The spherical reaction chamber design increases the gas mixing efficiency and reaction uniformity, improving product quality.

[0096] The tangential design of the ammonia pipe 16 optimizes the injection mode of ammonia and promotes full mixing and reaction with B2O3.

[0097] The heating coil on the outer wall of the reaction chamber 10 ensures the uniformity and stability of the reaction temperature, which is conducive to the production of high-quality boron nitride crystals.

[0098] The use of high-purity materials (such as boron nitride reaction chamber and discharge pipe) minimizes the introduction of impurities and improves product purity.

[0099] The precise control system enables real-time monitoring and adjustment of the entire process, greatly improving the consistency and repeatability of production.

[0100] The modular design facilitates maintenance and replacement, increasing the service life of the equipment and operational flexibility.

[0101] This embodiment improves the production efficiency, product quality and process controllability of pyrolytic boron nitride through the buffer system design and the precisely controlled reaction chamber structure. This design provides reliable technical support for the large-scale, high-quality industrial production of boron nitride.

[0102] Example 3

[0103] like Figures 1 to 12 As shown, based on embodiments 1 and 2, this embodiment focuses on the spiral structure design of the intake system and the detailed configuration of the balancing mechanism:

[0104] The air inlet pipe 5 is made of high-purity 316L stainless steel material and has a spiral structure, which is wound around the outer wall of the evaporation chamber 1. The starting end of the spiral structure is connected to the external air supply system, and the terminal end passes through the separation layer 3 and is connected to the inner wall of the separation layer 3.

[0105] The evaporation chamber 1 is made of high-temperature resistant molybdenum alloy material, and the bottom end of the evaporation chamber 1 is fixedly connected to the base by high-strength bolts.

[0106] The base is made of 304 stainless steel sheet and is equipped with leveling screws to accurately adjust the level of the entire device.

[0107] The balance bar 18 is made of titanium alloy material, has a length of 50 cm, and a cross-section of a rectangle of 2 cm x 1 cm. The center point of the balance bar 18 is rotatably connected to the base through a high-precision bearing and can rotate freely in a vertical plane.

[0108] The stage 2 is made of high-purity graphite material, and the bottom center of the stage 2 is rotatably connected to one end of the balance pole 18 via a micro universal joint to ensure that the stage 2 always remains horizontal.

[0109] The counterweight is made of tungsten alloy material, cylindrical, 5 cm in diameter, and height-adjustable. The counterweight is rotatably connected to the other end of the balance bar 18 by a threaded connection, and its position on the balance bar 18 can be adjusted by rotation, thereby changing the torque.

[0110] Working process:

[0111] Before starting the system, the operator adjusts the position of the counterweight on the balance bar 18 according to the initial mass of the boron oxide to keep the balance bar 18 level.

[0112] After starting the system, the external gas supply device inputs the nitrogen and hydrogen mixed gas into the intake pipe 5.

[0113] The mixed gas flows in the spirally structured intake pipe 5 and is heated at the same time. The spiral structure increases the residence time of the gas in the pipe, ensuring sufficient preheating and mixing.

[0114] The preheated gas enters the evaporation chamber 1 from the terminal end of the air inlet pipe 5 and is fully mixed with the vaporized boron oxide.

[0115] As the reaction proceeds, the boron oxide on stage 2 is gradually consumed and its mass decreases.

[0116] Due to the presence of the counterweight, the balance bar 18 begins to rotate slowly, causing the stage 2 to gradually rise, keeping the boron oxide always in the optimal heating position of the laser 6.

[0117] During the whole process, the rotation of the balance bar 18 is continuous and smooth, ensuring that the evaporation rate of the boron oxide remains constant.

[0118] When the boric oxide is consumed, the balance bar 18 reaches a preset maximum angle, triggering the termination switch, and the system automatically stops running or prompts to add new boric oxide.

[0119] The spiral structure of the air inlet pipe 5 significantly increases the preheating path of the gas, ensures that the temperature of the gas entering the evaporation chamber 1 is uniform, and improves the energy efficiency of the system.

[0120] The spiral design also increases the mixing time of the gases, ensuring that nitrogen and hydrogen are fully mixed, creating an ideal gas environment for subsequent reactions.

[0121] The design of the balance bar 18 and the counterweight enables automatic adjustment of the position of the boron oxide without manual intervention, thus greatly improving the automation level of the system.

[0122] The continuous rise of the stage 2 ensures that the boron oxide is always in the optimal heating position of the laser 6, thereby ensuring the stability of the boron oxide evaporation rate and improving the consistency of the B2O3 gas concentration.

[0123] The adjustability of the counterweight position enables the system to adapt to different initial masses of boron oxide, enhancing the flexibility and applicability of the equipment.

[0124] The design of the balancing mechanism eliminates the problem of frequent adjustment of the position of boron oxide in traditional methods, thereby improving production efficiency and consistency of product quality.

[0125] The leveling function of the base ensures the stability of the entire system and reduces the problem of uneven gas flow that may be caused by tilting.

[0126] The design of the entire balancing mechanism is simple and efficient, reducing moving parts and improving the reliability and service life of the system.

[0127] The automated position adjustment process reduces the need for operator intervention and improves the safety of the production process.

[0128] This embodiment significantly improves the automation level, operation stability and product quality consistency of the pyrolytic boron nitride reactor through the innovative spiral air intake system and intelligent balancing mechanism design. This design provides reliable technical support for continuous, efficient and high-quality boron nitride production and has broad industrial application prospects.

[0129] Example 4

[0130] like Figures 1 to 12 As shown, based on Examples 1, 2 and 3, this example describes in detail the complete workflow of the pyrolysis boron nitride reactor, including the following specific steps:

[0131] S1. Preparatory stage:

[0132] Accurately weigh 100 g of high-purity boron oxide (purity ≥ 99.99%) and place it on stage 2.

[0133] The position of the counterweight on the balance bar 18 is adjusted to keep the stage 2 level and the boron oxide at the focal position of the laser 6 (30 cm away from the laser 6).

[0134] Start the controller to preheat the system, set the temperature of evaporation chamber 1 to 800°C, and the preheating time to 30 minutes.

[0135] S2. Gas input and premixing:

[0136] Nitrogen gas (flow rate 2 L / min) and hydrogen gas (flow rate 0.5 L / min) were introduced into the spiral structure air inlet pipe 5 through mass flow controllers.

[0137] The spiral structure (20 turns, total length 3 m) promotes thorough mixing of nitrogen and hydrogen.

[0138] The preheating coil 12 heats the mixed gas to 500°C.

[0139] The air inlet pipe 5 is arranged tangentially to the evaporation chamber 1 (cut-in angle 30°) to ensure efficient mixing of the preheated mixed gas and the B2O3 gas.

[0140] S3. Boron oxide evaporation:

[0141] The laser 6 (power 500W) starts to heat the boron oxide on the stage 2, and the temperature is controlled at 1200±10°C.

[0142] As the boric oxide is consumed, the balance bar 18 is automatically adjusted, the counterweight moves downward, and the remaining boric oxide moves upward to maintain the optimal heating position.

[0143] The evaporation rate of boron oxide was maintained at 2 g / min to form stable gaseous B2O3.

[0144] Gaseous B2O3 and the preheated nitrogen-hydrogen mixed gas are fully mixed in the evaporation chamber 1, and the mixing time is about 2 seconds.

[0145] S4. Water separation:

[0146] The mixed gas passed through separation layer 3 (SOD molecular sieve membrane, thickness 2 mm, pore size 0.28 nm) at a flow rate of 2.5 L / min.

[0147] Water molecules (molecular diameter about 0.27nm) are selectively adsorbed, and the separation efficiency is >99%.

[0148] The separated water is collected in the water collection chamber, and about 10 mL of water is discharged through the pipeline every hour.

[0149] S5. Carbon monoxide separation:

[0150] The gas continues to pass through separation layer 2 (NaA (LTA) molecular sieve membrane, thickness 3 mm, pore size 0.41 nm).

[0151] Carbon monoxide (molecular diameter about 0.38nm) is selectively adsorbed, and the separation efficiency is >95%.

[0152] The separated carbon monoxide is collected in a carbon monoxide collection chamber and discharged through a pipeline at a rate of about 0.5 L per hour.

[0153] S6. Buffering process:

[0154] The purified gas enters buffer chamber 1 7, buffer chamber 2 8 and buffer chamber 3 9 in sequence.

[0155] The coil 14 outside the inner tube 13 of each buffer chamber heats the gas to 1000°C.

[0156] The solenoid valve 15 switches rapidly at a frequency of 100 Hz to accurately control the gas flow rate at 2.5±0.1 L / min.

[0157] The three-level buffer reduces gas concentration fluctuation to within ±1% and flow fluctuation to within ±2%.

[0158] S7. Reaction process:

[0159] The stable gas mixture enters the spherical reaction chamber (reaction chamber 10, diameter 50 cm).

[0160] The heating coil on the outer wall of the reaction chamber 10 maintains the temperature at 1500±5°C.

[0161] Ammonia gas preheated to 1000° C. was introduced through an ammonia gas pipe 16 provided tangentially (flow rate: 1.5 L / min).

[0162] B2O3 and NH3 react at high temperature, the reaction time is about 5 seconds, and the conversion rate is >98%.

[0163] S8.Product output:

[0164] The reaction product is transported to the deposition chamber through the discharge pipe 17 (inner diameter 5 cm).

[0165] The deposition chamber temperature was maintained at 1200 °C and the pressure was 0.1 atm.

[0166] Boron nitride was deposited as a thin film on a silicon substrate at a rate of 2 μm / min or collected as a powder at a rate of 1 g / min.

[0167] S9.Continuous operation:

[0168] The controller samples once every 0.1 seconds and adjusts the temperature (accuracy ±1°C), pressure (accuracy ±0.01atm) and gas flow (accuracy ±0.1L / min) in real time.

[0169] The heat insulation layer 11 (thermal conductivity <0.05 W / (m·K)) ensures that the system temperature is stable and the heat loss is <5%.

[0170] The balance bar 18 is automatically adjusted according to the weight of the boron oxide to ensure that the boron oxide is always in the best heating position.

[0171] The highly automated operation process significantly improves production efficiency and reduces human errors.

[0172] Precise temperature control and gas flow management ensure stable reaction conditions and improve consistent product quality.

[0173] The balance bar design realizes the automatic adjustment of the boron oxide position and ensures the stability of the B2O3 gas concentration.

[0174] The multi-stage separation and buffer system effectively removes impurities and significantly improves the purity of the reaction gas.

[0175] The spherical reaction chamber design optimizes gas mixing and reaction efficiency, and improves the conversion rate of boron nitride.

[0176] The real-time monitoring and adjustment system makes the production process more controllable and facilitates the timely detection and handling of problems.

[0177] The modular design facilitates equipment maintenance and upgrades, extending the service life of the equipment.

[0178] The efficient thermal management system reduces energy loss and improves overall energy efficiency.

[0179] The continuous and stable supply of raw materials ensures long-term stable operation and is suitable for large-scale industrial production.

[0180] The precise control system provides reliable data support for process parameter optimization and product quality improvement.

[0181] This example demonstrates the high efficiency and reliability of the pyrolytic boron nitride reactor in actual production through detailed operating steps and precise parameter control. This method can not only produce high-quality boron nitride products, but also has good scalability and industrial prospects.

[0182] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A pyrolytic boron nitride reactor, characterized in that: The invention comprises a controller and an evaporation chamber (1), wherein a loading platform (2) is slidably connected to the evaporation chamber (1), a separation layer 1 (3) and a separation layer 2 (4) are fixedly connected to the inner wall of the evaporation chamber (1), an air inlet pipe (5) is fixedly connected to the outer end of the evaporation chamber (1), one end of the air inlet pipe (5) passes through the separation layer 1 (3) and is in communication with the inner wall of the separation layer 1 (3), and the other end is connected to an external air supply system, the air inlet pipe (5) is arranged tangentially to the evaporation chamber (1), and the air inlet pipe (5) is used to introduce nitrogen and hydrogen, a laser (6) is fixedly connected to the evaporation chamber (1), and a buffer chamber 1 (7), a buffer chamber 2 (8), a buffer chamber 3 (9) and a reaction chamber (10) are fixedly connected to the top of the evaporation chamber (1) in sequence, the laser (6), the buffer chamber 1 (7), the buffer chamber 2 (8), the buffer chamber 3 (9) and the reaction chamber (10) are all electrically connected to the controller, and the loading platform (2) is used to contain boron oxide.

2. A pyrolytic boron nitride reactor according to claim 1, characterized in that: A moisture collection chamber and a carbon monoxide collection chamber are formed between the separation layer 1 (3) and the separation layer 2 (4) and the inner wall of the evaporation chamber (1), respectively, and the moisture collection chamber and the carbon monoxide collection chamber are connected to the external system through pipelines.

3. A pyrolytic boron nitride reactor according to claim 2, characterized in that: The separation layer 1 (3) and the separation layer 2 (4) are respectively made of a multi-layer SOD molecular sieve membrane and a multi-layer NaA (LTA) molecular sieve membrane. The SOD molecular sieve membrane is used to separate water, and the NaA (LTA) molecular sieve membrane is used to separate carbon monoxide.

4. A pyrolytic boron nitride reactor according to claim 3, characterized in that: The outer wall of the evaporation chamber (1) is fixedly connected to a heat insulation layer (11), the outer end of the air inlet pipe (5) is fixedly connected to a preheating coil (12), and the preheating coil (12) is electrically connected to a controller.

5. A pyrolytic boron nitride reactor according to claim 4, characterized in that: The buffer chamber 1 (7), the buffer chamber 2 (8) and the buffer chamber 3 (9) all comprise an inner tube (13), the outer wall of the inner tube (13) being fixedly connected to a coil (14), the outer wall of the coil (14) being fixedly connected to a heat insulation layer (11), the inner tube (13) being fixedly connected to an electromagnetic valve (15), and the coil (14) and the electromagnetic valve (15) being both electrically connected to a controller.

6. A pyrolytic boron nitride reactor according to claim 5, characterized in that: The reaction chamber (10) comprises a spherical reaction chamber, and an ammonia pipe (16) is fixedly connected to the outer wall of the spherical reaction chamber, and the ammonia pipe (16) is arranged tangentially to the spherical reaction chamber. A discharge pipe (17) is fixedly connected to the top of the spherical reaction chamber, and the discharge pipe (17) is connected to the deposition chamber. A heating coil is wound around the outer wall of the reaction chamber (10), and the heating coil is electrically connected to a controller.

7. A pyrolytic boron nitride reactor according to claim 6, characterized in that: The air inlet pipe (5) is a spiral structure, the bottom end of the evaporation chamber (1) is fixedly connected to a base, and a balance rod (18) is rotatably connected to the base.

8. A pyrolytic boron nitride reactor according to claim 7, characterized in that: One end of the balance rod (18) is rotatably connected to the bottom end of the loading platform (2), and the other end of the balance rod (18) is rotatably connected to a counterweight.

9. A method for using a pyrolytic boron nitride reactor according to any one of claims 1 to 8, characterized in that: The steps include: S1, preparation stage: placing boron oxide on the stage (2), adjusting the position of the boron oxide by means of a balance bar (18) and a counterweight so that the boron oxide is in the optimal heating position of the laser (6), starting the controller, and starting system preheating; S2. Gas input and premixing: nitrogen and hydrogen are input through the spirally structured intake pipe (5). The spiral structure promotes the full mixing of nitrogen and hydrogen. The mixed gas is heated by the preheating coil (12) outside the intake pipe (5). The intake pipe (5) is arranged tangentially to the evaporation chamber (1) to ensure that the preheated and mixed gas can fully mix and react with the B2O3 gas. S3, boron oxide evaporation: the laser (6) starts to heat the boron oxide on the stage (2). As the boron oxide is consumed, the counterweight of the balance bar (18) moves downward, causing the remaining boron oxide to move upward and remain at the optimal heating position. The boron oxide evaporates to form gaseous B2O3, which is fully mixed with the preheated nitrogen and hydrogen mixture in the evaporation chamber (1). S4, water separation: the mixed gas passes through the separation layer 1 (3) (SOD molecular sieve membrane), the water molecules are separated and collected in the water collection chamber, and then discharged through the pipeline; S5. Carbon monoxide separation: The gas continues to pass through separation layer two (4) (NaA (LTA) molecular sieve membrane), where carbon monoxide is separated and collected in a carbon monoxide collection chamber and then discharged through a pipeline. S6, buffer process: the purified gas enters buffer chamber 1 (7), buffer chamber 2 (8) and buffer chamber 3 (9) in sequence. The inner tube (13) of each buffer chamber is heated by a coil (14) outside. The solenoid valve (15) controls the gas flow rate to ensure a stable gas supply. The buffer chamber system smoothes the fluctuation of gas concentration and flow rate. S7, reaction process: a stable gas mixture enters the reaction chamber (10), the outer wall of the reaction chamber (10) is wound with a heating coil to heat the reaction chamber to ensure the stability of the reaction temperature, ammonia is input through the tangentially arranged ammonia pipe (16) and is fully mixed with the B2O3 gas. Under high temperature conditions, B2O3 and NH3 react to generate boron nitride; S8, product output: the reaction product is transported to the deposition chamber through the discharge pipe (17), so that the boron nitride is deposited to form a film or powder; S9. Continuous operation: During the whole process, the controller continuously monitors and adjusts the temperature, pressure and gas flow of each part. The thermal insulation layer (11) ensures the temperature stability of the whole system. The balance bar (18) ensures that the boron oxide always remains in the optimal heating position, thus achieving a continuous and stable supply of raw materials.

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