Apparatus and method for preparing monodisperse nano tungsten carbide by flow type gas phase carbonization
By using a flow-type gas phase carbonization device, a spiral flow field is formed by a screw feeder and a venturi tube to achieve molecular-level mixing of WO3 and activated carbon. This solves the problems of incomplete reaction and product agglomeration in existing technologies, and realizes efficient and pure nano-WC preparation and waste heat utilization.
Patent Information
- Application Number
- CN202610389376.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-27
- Publication Date
- 2026-07-14
AI Technical Summary
In existing WC preparation technologies, it is difficult to achieve uniform molecular-level contact between tungsten and carbon sources, resulting in poor reaction kinetics, residual impurities, a lack of precise temperature control during product cooling, and intermittent equipment design without considering the resource utilization of waste gas.
The system employs a flow-type gas phase carbonization device, which uses a screw feeder to transport WO3 powder. Combined with a venturi tube and guide plate, a spiral flow field is formed to achieve molecular-level mixing of WO3 and activated carbon atoms. Waste heat from the exhaust gas is also recovered to achieve efficient and continuous production.
It achieves molecular-level uniform contact between WO3 and activated carbon, resulting in high product purity, reduced impurities, and no particle agglomeration, meeting the requirements of monodisperse nanomaterials. Waste heat recovery from exhaust gas reduces energy consumption and complies with green production standards.
Smart Images
Figure CN122377381A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to an apparatus and method for preparing monodisperse nano-tungsten carbide by flow-through gas-phase carbonization. Background Technology
[0002] Tungsten carbide (WC) is widely used in cemented carbide cutting tools, high-temperature structural components for aerospace, and electrode materials for new energy due to its high hardness, excellent wear resistance, and high-temperature stability. As downstream products develop towards higher precision and lighter weight, higher requirements are placed on the particle size, dispersibility, and purity of WC raw materials. Existing preparation technologies are mainly divided into traditional solid-state sintering, liquid-phase, and traditional gas-phase methods.
[0003] Traditional solid-state sintering is currently the mainstream method for industrial preparation of carbon dioxide (WC). Its core is the solid-state reaction between WO3 and carbon black (C) to generate WC. However, solid-state sintering has significant drawbacks: First, the mixing of solid raw materials relies on mechanical ball milling, making it difficult for WO3 and C to achieve atomic-level contact, resulting in incomplete reactions and the presence of impurity phases such as W, WO2, and W2C. Second, during high-temperature sintering, WC particles are prone to Ostwald ripening, with particle sizes mostly ranging from 100-500 nm, and exhibit severe agglomeration. Furthermore, this method requires intermittent operation, including loading-sintering-cooling-unloading, resulting in low production efficiency and making it difficult to meet the needs of large-scale production.
[0004] The liquid-phase method involves forming a precursor from tungstates such as Na₂WO₄ and organic carbon sources such as glucose and citric acid in solution, followed by drying and calcination carbonization to prepare WC powder. While this method can reduce particle size, it suffers from the potential for generating byproducts such as tar and CO₂ during the carbonization process of the organic carbon source, leading to fluctuations in the carbon content of the WC powder. Furthermore, the presence of Na₂WO₄ in the solution... + Cl - Ions are difficult to remove completely, and the impurity content is >0.5%, which affects the mechanical properties of WC; moreover, the drying of the precursor is prone to forming hard agglomerates, which cannot be completely eliminated during subsequent carbonization.
[0005] The gas-phase method generates WC by reacting volatile tungsten sources such as WF6 and WOCl4 with carbon source gases at high temperatures. The problems with this method are that the tungsten sources WF6 and WOCl4 are highly corrosive and can easily damage equipment; gas mixing relies on static mixers, which can easily lead to a "concentration gradient", resulting in uneven growth of WC particles in the gas phase and a high agglomeration rate; and it is mostly used to prepare coatings, such as WC coatings on the surface of cutting tools, and it is difficult to mass-produce powdered WC products.
[0006] In summary, the fundamental problem with existing WC preparation technologies lies in: (1) It is difficult to achieve uniform molecular-level contact between the tungsten source and the carbon source in the reaction system, resulting in poor reaction kinetics and residual impurities; (2) The product cooling process lacks precise temperature control, and the particles are prone to growing and agglomerating; (3) Most of the equipment is designed for intermittent use and the resource utilization of waste gas is not considered. Summary of the Invention
[0007] The purpose of this invention is to address the problems of incomplete WC preparation reaction, product agglomeration, low purity, and low production efficiency in the existing technology, and to provide a flow-type gas-phase carbonization equipment and method for preparing monodisperse nano-tungsten carbide. The method achieves molecular-level reaction between WO3 and carbon source through multi-region synergistic regulation, while utilizing waste heat recovery from exhaust gas, thus taking into account both product performance and green production.
[0008] To achieve the above objectives, the present invention provides the following technical solution: A flow-type gas-phase carbonization apparatus for preparing monodisperse nano-tungsten carbide includes a raw material supply unit, a carbon source heating and decomposition unit, a gas-phase reaction unit, a cooling and collection unit, and a waste heat utilization unit. The raw material supply unit includes a solid feed unit for conveying WO3 powder, a carbon source supply unit for providing carbon source gas, and an argon supply unit for introducing inert carrier gas. The solid feeding unit includes a hopper, a screw feeder, and a motor. The bottom outlet of the hopper is connected to the inlet of the screw feeder, and the output shaft of the motor is connected to the screw shaft of the screw feeder. The carbon source heating and decomposition unit includes a heating chamber, which is sleeved on the outer periphery of the discharge end of the screw feeder, and a tubular furnace is sleeved on the periphery of the heating chamber; The gas phase reaction unit includes a reduction reactor and a Venturi tube disposed at its inlet. The inlet end of the Venturi tube is connected to the outlet end of the heating chamber. Square guide plates are evenly distributed axially on the inner wall of the reduction reactor. When a mixed gas flow containing WO3 gas molecules, activated carbon atoms and argon enters the reduction reactor at high speed from the Venturi tube, the flow pattern of the gas flow changes from axial flow to a combined axial and circumferential flow due to the impact of the gas flow on the guide plates, forming a spiral flow. The carbon source supply unit includes a methane cylinder, and the carbon source supply pipeline is led out from the methane cylinder, passes through the heating chamber, and is connected at the end to the inlet of the venturi tube. The argon supply unit includes an argon cylinder, and the argon supply pipeline is led out from the argon cylinder and connected to the inlet of the heating chamber at its end. The cooling collection unit includes a gas-solid separation device, a water cooling device, and a water-gas separation device connected in sequence, wherein the air inlet of the gas-solid separation device is connected to the discharge end of the reduction reactor via an air cooling pipe. The waste heat utilization unit includes a combustion chamber. The air inlet of the combustion chamber is connected to the air outlet of the water-gas separator and the air inlet. The carbon source supply pipeline is led out from the methane cylinder. The middle section of the screw feeder is used to transport WO3 powder to the heating chamber. Both are installed in the heating area of the combustion chamber before entering the heating chamber.
[0009] Furthermore, the included angle between adjacent guide plates is 135°, and the surface of each guide plate is coated with a yttrium oxide high-temperature resistant coating with a coating thickness of 30 μm.
[0010] Furthermore, the length of the spiral feeder extending through the combustion chamber heating area is 1 / 2 of its total length, and the length of the carbon source gas supply pipeline extending through the combustion chamber heating area is 1 / 3 of its total length.
[0011] Furthermore, the ratio of the throat diameter to the inlet diameter of the venturi tube is 1:2.5, the length of the throat section is 1.5 times the inlet diameter, and the inner wall of the venturi tube is provided with serrated turbulence protrusions with a height of 0.5 mm and a spacing of 2 mm.
[0012] Furthermore, the water cooling device has a sleeve structure, with the inner tube connecting the gas outlet of the gas-solid separation device and the air inlet of the water-gas separation device, and the outer tube serving as a cooling water circulation channel. The water inlet of the outer tube is equipped with a flow regulating valve for adjusting the cooling water flow rate.
[0013] Furthermore, a removable collection tank is provided at the bottom of the gas-solid separation device.
[0014] Furthermore, the units are connected by sealed pipelines, and flanges are provided at the interfaces of adjacent units; the combustion chamber, screw feeder and carbon source gas supply pipeline are all covered with a heat insulation layer.
[0015] Gas control units, including pressure gauges, pressure reducing valves, flow meters, and gas circuit switches, are installed on both the carbon source gas supply pipeline and the argon gas supply pipeline. Temperature sensors are installed in the middle section of the screw feeder, the heating chamber, and the combustion chamber. The gas control units and temperature sensors are electrically connected to independent temperature control and gas circuit regulation modules.
[0016] This invention also provides a method for preparing monodisperse nano-tungsten carbide by flow-through gas-phase carbonization, comprising the following steps: Step 1: Preparation of raw materials and gas lines Add WO3 powder with a purity of ≥99.9% and a particle size of 5μm to the hopper, start the motor to drive the screw feeder to run at a speed of 5-15r / min, and transport the WO3 powder to the heating chamber; at the same time, turn on the gas circuit switch on the argon gas supply pipeline to introduce argon gas into the heating chamber, and adjust the argon gas pressure to 0.1~0.2MPa and control the flow rate to 50~150sccm through the pressure reducing valve and flow meter on the argon gas supply pipeline. Step 2: WO3 sublimation and carbon source decomposition Start the tube furnace and heat the heating chamber to 1100-1200℃ to preheat and sublimate the WO3 powder. The sublimated WO3 gas is then sent into the Venturi tube. The heated methane decomposes in the heating chamber to produce active carbon atoms: CH4→C (active) + 2H2↑. Step 3: Gas-phase reduction carbonization WO3 gaseous molecules enter the Venturi tube with the argon gas flow, forming a high-speed gas flow with activated carbon atoms and argon. After passing through the guide plate and forming a spiral flow field, they enter the reduction reactor, where a carbothermic reduction reaction occurs at a high temperature of 1100-1200℃: WO3 (gaseous) + 4C (activated) → WC (gaseous) + 2CO↑. The gas flow rate is controlled to prevent particle growth. Step 4: Product collection and exhaust gas treatment After being air-cooled, the WC gaseous product enters a gas-solid separation device to separate WC particles from gases CO, H2, and argon. The separated WC particles are then cooled to room temperature by a water-cooling device and then removed by a water-gas separation device to obtain monodisperse nano WC powder. Step 5: Exhaust gas recirculation preheating The separated exhaust gases CO and H2 enter the combustion chamber for recycling. CO and H2 undergo exothermic reactions in the combustion chamber: 2CO + O2 → 2CO2 and 2H2 + O2 → 2H2O. The released heat is used to heat the middle section of the screw feeder and the methane gas supply pipeline to 200-300℃ respectively, so as to preheat the WO3 powder and methane gas and improve the subsequent decomposition efficiency. The exhaust gas after combustion is purified and discharged through the exhaust port.
[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention is based on the principle of flow-type multi-region synergistic control. WO3 powder is uniformly conveyed to the heating chamber via a screw feeder, achieving uniform generation and stable supply of WO3 gaseous species. Simultaneously, methane gas, after being preheated by waste heat from the combustion chamber, undergoes high-temperature pyrolysis in a tubular furnace to generate activated carbon species. The flow field is optimized through a venturi tube and a spiral guide plate, achieving molecular-level uniform mixing of activated carbon species and WO3 gaseous molecules. Combined with rapid temperature control via a water-cooling device and waste heat recovery from the combustion chamber, this invention achieves efficient preparation and energy recycling of monodisperse nano-WOC particles. Compared to traditional preparation methods, this equipment improves reaction thoroughness by achieving molecular-level mixing through a venturi tube and spiral guide plate. WO3 reacts completely with activated carbon atoms, resulting in high product purity and reducing the generation of impurity phases such as W and WO2. The "tungsten source-carbon source" achieves uniform molecular-level contact, and rapid cooling inhibits particle growth and agglomeration, meeting the requirements for monodisperse nanomaterials. Waste heat recovery from CO and H2 combustion reduces energy consumption, and there are no direct emissions of harmful gases, complying with green production standards. The continuous flow design shortens the production cycle compared to intermittent solid-phase methods, enabling large-scale preparation.
[0018] This invention utilizes guide plates installed on the inner wall of a reduction reactor. When a mixed gas stream containing WO3 gaseous molecules, activated carbon atoms, and argon enters the reduction reactor at high speed through a venturi tube, the flow pattern changes from axial to a combined axial and circumferential flow due to the impact of the gas stream on the guide plates, forming a spiral flow. Ultimately, a "spiral upward" flow field is formed within the reduction reactor. The centrifugal force generated during the rotation of the gas stream ensures thorough mixing of WO3 gaseous molecules with slight density differences with activated carbon atoms, eliminating the problem of "locally excessively high / low concentrations." This extends the contact path of the reactants from the "short path" of traditional straight flow to a "spiral path," prolonging the contact time and increasing the probability of molecular-level contact, ensuring a thorough reduction and carbonization reaction. Furthermore, the centrifugal force generated by the spiral flow field can "disperse" the WC nanoparticle clusters initially formed in the gaseous reaction, preventing particle aggregation in the gas phase due to van der Waals forces. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; the arrows in the diagram indicate the direction of material / airflow. In the diagram: 1-Heating chamber; 2-Tube furnace; 3-Motor; 4-Methane cylinder; 5-Argon cylinder; 6-Guide plate; 7-Reduction reactor; 8-Venturi tube; 9-Gas-solid separation device; 10-Water cooling device; 11-Water-gas separation device; 12-Combustion chamber; 13-Air inlet; 14-Hopper; 15-Exhaust port; 16-Screw feeder. Detailed Implementation
[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0021] like Figure 1 As shown in this embodiment, the apparatus for preparing monodisperse nano-tungsten carbide by flow-through gas-phase carbonization includes a raw material supply unit, a carbon source heating and decomposition unit, a gas-phase reaction unit, a cooling and collection unit, and a waste heat utilization unit. The units are connected by sealed pipelines, and flanges are provided at the interfaces of adjacent units to achieve reliable sealing and quick assembly / disassembly.
[0022] The raw material supply unit includes a solid feed unit for conveying WO3 powder, a carbon source supply unit for providing carbon source gas, and an argon supply unit for introducing inert carrier gas.
[0023] The solid feeding unit includes a hopper 14, a screw feeder 16, and a motor 3. The bottom outlet of the hopper 14 is connected to the inlet of the screw feeder 16. The output shaft of the motor 3 is connected to the screw shaft of the screw feeder 16 to drive the screw blades to rotate, thereby quantitatively conveying the WO3 powder in the hopper 14 to the downstream. The screw feeder 16 is covered with an insulation layer to reduce heat loss of the WO3 powder during the conveying process and prevent it from condensing or bridging.
[0024] The carbon source heating and decomposition unit includes a heating chamber 1, which is installed around the discharge end of the screw feeder 16, and a tubular furnace 2 is installed around the heating chamber 1.
[0025] The gas-phase reaction unit includes a reduction reactor 7 and a venturi tube 8 located at its inlet. The inlet end of the venturi tube 8 is connected to the outlet end of the heating chamber 1. Square guide plates 6 are evenly distributed axially on the inner wall of the reduction reactor 7. The included angle between adjacent guide plates 6 is 135°. The surface of each guide plate 6 is coated with a yttrium oxide high-temperature resistant coating with a coating thickness of 30 μm. When a mixed gas stream containing WO3 gaseous molecules, activated carbon atoms, and argon enters the reduction reactor 7 at high speed from the Venturi tube 8, the flow pattern changes from axial flow to a combined axial and circumferential flow due to the impact of the airflow on the guide plate 6, forming a spiral flow. Ultimately, a "spiral upward" flow field is formed within the reduction reactor 7. The centrifugal force generated during the rotation of the airflow ensures that the WO3 gaseous molecules with slight density differences are fully mixed with the activated carbon atoms, eliminating the problem of "locally high / low concentration". This extends the contact path of the reactants from the "short path" of the traditional straight flow to a "spiral path", prolonging the contact time and increasing the probability of molecular-level contact, ensuring a thorough reduction and carbonization reaction. Furthermore, the centrifugal force generated by the spiral flow field can "disperse" the WC nanoparticle clusters initially formed in the gaseous reaction, preventing the particles from agglomerating in the gas phase due to van der Waals forces. The ratio of the throat diameter to the inlet diameter of the Venturi tube 8 is 1:2.5, and the length of the throat section is 1.5 times the inlet diameter. The inner wall of the Venturi tube 8 is provided with serrated turbulence protrusions with a height of 0.5 mm and a spacing of 2 mm.
[0026] The carbon source supply unit includes a methane cylinder 4. The carbon source supply pipeline extends from the methane cylinder 4, passes through the heating chamber 1, and connects to the inlet of the venturi tube 8 at its end. To prevent heat loss and maintain the temperature of the methane gas, the carbon source supply pipeline is covered with an insulation layer.
[0027] The argon supply unit includes an argon cylinder 5, and the argon supply pipeline is led out from the argon cylinder 5 and connected to the inlet end of the heating chamber 1.
[0028] The cooling and collection unit includes a gas-solid separation device 9, a water cooling device 10, and a water-gas separation device 11 connected in sequence. The air inlet of the gas-solid separation device 9 is connected to the outlet of the reduction reactor 7 via an air cooling pipe. The gas-solid separation device 9 separates the monodisperse nano-WC powder generated after the reduction reaction. The water cooling device 10 and the water-gas separation device 11 rapidly cool the water and gas to achieve complete gas-water separation. A detachable collection tank is provided at the bottom of the gas-solid separation device 9. The water cooling device 10 has a sleeve structure. The inner tube connects the air outlet of the gas-solid separation device 9 to the air inlet of the water-gas separation device 11, and the outer tube is a cooling water circulation channel. The water inlet of the outer tube is equipped with a flow regulating valve for adjusting the cooling water flow rate.
[0029] The waste heat recovery unit includes a combustion chamber 12. The inlet of the combustion chamber 12 is connected to the outlet of the water-gas separator 11 and the air inlet 13. The carbon source supply pipeline leads out from the methane cylinder 4. The middle section of the screw feeder 16 is used to feed WO3 powder to the heating chamber 1. Both are installed within the heating area of the combustion chamber 12 before entering the heating chamber 1. The length of the screw feeder 16 within the heating area of the combustion chamber 12 is 1 / 2 of its total length, and the length of the carbon source supply pipeline within the heating area of the combustion chamber 12 is 1 / 3 of its total length. The combustion chamber 12 uses process waste gas CO and H2 as fuel for combustion. The heat generated is used to preheat the WO3 powder in the screw feeder 24 and the methane gas in the carbon source supply pipeline, respectively, to achieve energy recycling. The combustion chamber 12 is equipped with an exhaust port 15, through which the purified exhaust gas is discharged after combustion. To reduce heat loss, the outer periphery of the combustion chamber 12 is covered with an insulation layer.
[0030] Gas control units, including pressure gauges, pressure reducing valves, flow meters, and gas circuit switches, are installed on both the carbon source supply pipeline and the argon supply pipeline. Temperature sensors are installed in the middle section of the screw feeder 16, the heating chamber 1, and the combustion chamber 12. The gas control units and temperature sensors are electrically connected to independent temperature control and gas circuit regulation modules to achieve precise and coordinated control of gas parameters and reaction temperature.
[0031] A method for preparing monodisperse nano-tungsten carbide by flow-through gas-phase carbonization: Step 1: Preparation of raw materials and gas lines Add WO3 powder with a purity ≥99.9% and a particle size of 5μm to hopper 14, start motor 3 to drive screw feeder 16 to run at a speed of 5-15r / min to transport WO3 powder to heating chamber 1; at the same time, turn on the gas circuit switch on the argon gas supply pipeline to introduce argon gas into heating chamber 1, and adjust the argon gas pressure to 0.1~0.2MPa and control the flow rate to 50~150sccm through the pressure reducing valve and flow meter on the argon gas supply pipeline. Step 2: WO3 sublimation and carbon source decomposition Start the tube furnace 2 and heat the heating chamber 1 to 1100-1200℃ to achieve the initial preheating and sublimation of WO3 powder. The sublimated WO3 gas is then sent into the Venturi tube 8. The heated methane enters the heating chamber 1 and decomposes to produce active carbon atoms. The specific reaction formula is: CH4→ C (active) + 2H2↑. Step 3: Gas-phase reduction carbonization WO3 gaseous molecules enter the Venturi tube 8 with the argon gas flow, forming a high-speed gas flow with activated carbon atoms and argon gas. After passing through the guide plate 6 to form a spiral flow field, it enters the reduction reactor 7, where a carbothermic reduction reaction occurs at a high temperature of 1100-1200℃. The specific reaction formula is: WO3 (gaseous) + 4C (activated) → WC (gaseous) + 2CO↑. Step 4: Product collection and exhaust gas treatment After being air-cooled, the WC gaseous product enters the gas-solid separation device 9 to separate the WC particles from the gases CO, H2, and argon. The separated WC particles enter the water-cooling device 10 to cool to room temperature, and then pass through the water-gas separation device 11 to remove residual water vapor, thus obtaining monodisperse nano WC powder. Step 5: Exhaust gas recirculation preheating The separated exhaust gases CO and H2 enter the combustion chamber 12 for recycling and combustion. CO and H2 undergo exothermic reactions in the combustion chamber 12: 2CO + O2 → 2CO2 and 2H2 + O2 → 2H2O. The released heat is used to heat the middle section of the screw feeder 16 and the methane gas supply pipeline to 200-300℃ respectively, so as to preheat the WO3 powder and methane gas and improve the subsequent decomposition efficiency. The exhaust gas after combustion is purified and discharged through the exhaust port 15.
Claims
1. An apparatus for preparing monodisperse nano-tungsten carbide by flow-through gas-phase carbonization, characterized in that, It includes a raw material supply unit, a carbon source heating and decomposition unit, a gas phase reaction unit, a cooling and collection unit, and a waste heat utilization unit. The raw material supply unit includes a solid feed unit for conveying WO3 powder, a carbon source supply unit for providing carbon source gas, and an argon supply unit for introducing inert carrier gas. The solid feeding unit includes a hopper (14), a screw feeder (16) and a motor (3). The bottom outlet of the hopper (14) is connected to the inlet of the screw feeder (16), and the output shaft of the motor (3) is connected to the screw shaft of the screw feeder (16). The carbon source heating and decomposition unit includes a heating chamber (1), which is sleeved on the outer periphery of the discharge end of the screw feeder (16), and a tubular furnace (2) is sleeved on the periphery of the heating chamber (1). The gas phase reaction unit includes a reduction reactor (7) and a Venturi tube (8) located at its inlet. The inlet end of the Venturi tube (8) is connected to the outlet end of the heating chamber (1). Square guide plates (6) are evenly distributed axially on the inner wall of the reduction reactor (7). When a mixed gas flow containing WO3 gas phase molecules, activated carbon atoms and argon enters the reduction reactor (6) at high speed from the Venturi tube (8), the flow mode of the gas flow changes from axial flow to a combined axial and circumferential flow due to the impact of the gas flow on the guide plate (6), forming a spiral flow. The carbon source supply unit includes a methane cylinder (4), and the carbon source supply pipeline is led out from the methane cylinder (4), passes through the heating chamber (1), and its end is connected to the inlet end of the venturi tube (8). The argon supply unit includes an argon cylinder (5), and the argon supply pipeline is led out from the argon cylinder (5) and connected at the end to the inlet of the heating chamber (1); The cooling collection unit includes a gas-solid separation device (9), a water cooling device (10), and a water-gas separation device (11) connected in sequence. The air inlet of the gas-solid separation device (9) is connected to the outlet of the reduction reactor (7) via an air cooling pipe. The waste heat utilization unit includes a combustion chamber (12). The air inlet of the combustion chamber (12) is connected to the air outlet of the water-gas separator (11) and the air inlet (13). The carbon source gas supply pipeline is led out from the methane cylinder (4). The middle section of the screw feeder (16) is used to transport WO3 powder to the heating chamber (1). Both are installed in the heating area of the combustion chamber (12) before entering the heating chamber (1).
2. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to claim 1, characterized in that, The included angle between adjacent guide plates (6) is 135°, and each guide plate (6) is coated with a yttrium oxide high-temperature resistant coating with a coating thickness of 30 μm.
3. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to claim 1, characterized in that, The length of the spiral feeder (16) passing through the heating area of the combustion chamber (12) is 1 / 2 of its total length, and the length of the carbon source gas supply pipeline passing through the heating area of the combustion chamber (12) is 1 / 3 of its total length.
4. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to claim 1, characterized in that, The ratio of the throat diameter to the inlet diameter of the Venturi tube (8) is 1:2.5, and the length of the throat section is 1.5 times the inlet diameter. The inner wall of the Venturi tube (8) is provided with serrated turbulence protrusions with a height of 0.5 mm and a spacing of 2 mm.
5. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to claim 1, characterized in that, The water cooling device (10) is a sleeve structure. The inner tube connects the gas-solid separation device (9) outlet end and the water-gas separation device (11) inlet end. The outer tube is a cooling water circulation channel. The water inlet end of the outer tube is equipped with a flow regulating valve for adjusting the cooling water flow rate.
6. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to claim 1, characterized in that, A removable collection tank is provided at the bottom of the gas-solid separation device (9).
7. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to any one of claims 1-6, characterized in that, Each unit is connected by a sealed pipeline, and a flange is provided at the interface of adjacent units; the combustion chamber (12), the screw feeder (16) and the carbon source gas supply pipeline are all covered with a heat insulation layer.
8. The apparatus for preparing monodisperse nano-tungsten carbide by flow-type gas-phase carbonization according to claim 7, characterized in that, Gas control units, including pressure gauges, pressure reducing valves, flow meters and gas switches, are installed on both the carbon source gas supply pipeline and the argon gas supply pipeline. Temperature sensors are installed in the middle section of the screw feeder (16), the heating chamber (1) and the combustion chamber (12). The gas control units and temperature sensors are electrically connected to independent temperature control and gas regulation modules.
9. The method for preparing monodisperse nano-tungsten carbide by flow-through gas-phase carbonization using the equipment according to claim 8, characterized in that, Includes the following steps: Step 1: Preparation of raw materials and gas lines Add WO3 powder with a purity of ≥99.9% and a particle size of 5μm to the hopper (14), start the motor (3) to drive the screw feeder (16) to run at a speed of 5-15r / min, and transport the WO3 powder to the heating chamber (1); at the same time, turn on the gas circuit switch on the argon gas supply pipeline to introduce argon gas into the heating chamber (1), and adjust the argon gas pressure to 0.1~0.2MPa and control the flow rate to 50~150sccm through the pressure reducing valve and flow meter on the argon gas supply pipeline; Step 2: WO3 sublimation and carbon source decomposition Start the tube furnace (2) and heat the heating chamber (1) to 1100-1200℃ to preheat and sublimate the WO3 powder. The sublimated WO3 gas is then sent into the Venturi tube (8). The heated methane enters the heating chamber (1) and decomposes to produce active carbon atoms: CH4→C (active) + 2H2↑. Step 3: Gas-phase reduction carbonization WO3 gas molecules enter the Venturi tube (8) with the argon gas flow, forming a high-speed gas flow with active carbon atoms and argon gas. After passing through the guide plate (6) to form a spiral flow field, they enter the reduction reactor (7) and undergo a carbothermic reduction reaction at a high temperature of 1100-1200℃: WO3 (gaseous) + 4C (active) → WC (gaseous) + 2CO↑; Step 4: Product collection and exhaust gas treatment After being air-cooled, the WC gaseous product enters the gas-solid separation device (9) to separate the WC particles from the gases CO, H2, and argon. The separated WC particles enter the water-cooling device (10) to cool to room temperature, and then pass through the water-gas separation device (11) to remove residual water vapor, thus obtaining monodisperse nano WC powder. Step 5: Exhaust gas recirculation preheating The separated exhaust gases CO and H2 enter the combustion chamber (12) for recycling and combustion. CO and H2 undergo an exothermic reaction in the combustion chamber (12): 2CO + O2 → 2CO2 and 2H2 + O2 → 2H2O. The released heat is used to heat the middle section of the screw feeder (16) and the methane gas supply pipeline to 200-300℃ respectively, so as to preheat WO3 powder and methane gas and improve the subsequent decomposition efficiency. The exhaust gas after combustion is purified and discharged through the exhaust port (15).