Fine powder high-pressure feeding and solid discharging integrated device based on supercritical reaction kettle and application method

Abstract

The invention discloses a supercritical reaction kettle-based fine powder high-pressure feeding and solid discharging integrated device and an application method. The supercritical reaction kettle-based fine powder high-pressure feeding and solid discharging integrated device comprises a feeding system, a discharging system and a monitoring system, the feeding system comprises a feeding lock hopper and a supercritical reaction kettle; the discharging system comprises a double-cavity parallel interlocking hopper, a transition kettle and a product collecting chamber; the monitoring system comprises a pressure sensor, a temperature sensor, a differential pressure sensor and a control unit; the double-cavity parallel lock hopper comprises a lock hopper A and a lock hopper B; when the lock hopper A is communicated with the supercritical reaction kettle and disconnected from the transition kettle, the lock hopper B is communicated with the transition kettle and disconnected from the supercritical reaction kettle; the control unit controls alternate operation of the double-cavity parallel lock buckets. According to the device, non-kettle-stop feeding of fine powder is achieved through pressure equalizing of the feeding lock hopper and pulse propulsion, continuous discharging of the discharging system is achieved through alternate operation of the double-cavity parallel lock hopper, it is ensured that the whole feeding and discharging process is stably and efficiently conducted under the supercritical condition, and the overall efficiency and quality of high-pressure feeding of the fine powder and solid discharging are effectively improved.

Description

Technical Field

[0001] This application relates to the field of ultrafine powder technology, and mainly to an integrated device and application method for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor. Background Technology

[0002] High-temperature and high-pressure process engineering, especially supercritical water (SCW) technology, has shown great potential in materials synthesis, waste treatment, and energy conversion. Due to its unique physicochemical properties—significantly reduced polarity of water molecules and the disappearance of hydrogen bonds—supercritical water becomes an ideal medium for the reduction reactions of metal oxides. In particular, supercritical water discharge technology can generate high-energy electrons, ions, and long-lived hydrogen atoms through high-voltage discharge. H As a strong reducing agent, it can preferentially react with metal oxides (such as Fe2O3, Al2O3, ZnO) to generate metallic elements. At the same time, it can promote the generation of hydrogen gas, transforming supercritical water, which is originally an oxidizing environment, into a reducing system. This provides an efficient route for the preparation of metallic elements and alloys (such as Cu-Fe and Cu-Al nanoalloys), and has important application potential in the field of advanced materials synthesis.

[0003] However, existing supercritical water reduction technology for metal oxides has significant limitations in material transport and product processing. On one hand, traditional feeding methods involve open-top loading, requiring shutdown and depressurization before fine powder can be added. This not only leads to prolonged downtime and low production efficiency but also poses a flash evaporation safety risk, and air entering the system can easily cause pre-oxidation of the raw materials. On the other hand, high-density fine powder is prone to agglomeration and deposition in high-pressure pipelines, forming bridging and causing pipeline blockage, affecting reaction uniformity. Simultaneously, the reduction products (such as elemental Fe) are magnetic and easily agglomerate. When exposed to air or water / vapor, they undergo rehydration oxidation reactions during cooling to subcritical or ambient temperatures, resulting in decreased product purity. Traditional shutdown-based discharge methods further exacerbate the product oxidation problem, leading to poor repeatability and difficulty in meeting the demands of mass production.

[0004] Furthermore, the supercritical water reaction system has stringent requirements for controlling operating parameters, needing to maintain a supercritical state at a temperature of 385℃-405℃ and a pressure of 22MPa-30MPa to prolong the H+ reaction. Lifespan, while also needing to control parameters such as discharge power and frequency to ensure H Concentration is a concern, and existing devices lack an integrated control mechanism for pressure, temperature, and material transport, which can easily lead to problems such as excessive pressure fluctuations in the main vessel and uneven local reactions, further restricting reaction efficiency and product quality stability.

[0005] In summary, developing an integrated device for high-pressure feeding of fine powders and solid discharge suitable for supercritical reactors is of paramount technical value in overcoming the current bottlenecks in production continuity, product purity, and operational stability faced by supercritical water reduction of metal oxides. Breakthroughs in this area are expected to significantly improve downtime issues and product oxidation problems associated with traditional feeding methods, thereby further promoting the in-depth application and sustainable development of high-temperature and high-pressure process engineering in the field of advanced materials synthesis, and enabling the efficient production of high-end functional metal materials. Summary of the Invention

[0006] In response to the problems in existing technologies, such as prolonged downtime due to opening the lid for filling and stopping the machine for discharging, high risk of flash evaporation, product oxidation, easy agglomeration and blockage of pipelines by high-density fine powder, and large pressure fluctuations and poor reaction uniformity in the main reactor due to difficulty in controlling reaction parameters, this application proposes an integrated device and application method for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor.

[0007] According to one aspect of the present invention, an integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor is provided, comprising a feeding system, a discharge system, and a monitoring system; the feeding system includes a feeding hopper and a supercritical reactor; the discharge system includes a dual-chamber parallel hopper, a transition vessel, and a product collection chamber; the monitoring system includes a pressure sensor, a temperature sensor, a differential pressure sensor, and a control unit; the dual-chamber parallel hopper includes hopper A and hopper B; when hopper A is connected to the supercritical reactor and disconnected from the transition vessel, hopper B is connected to the transition vessel and disconnected from the supercritical reactor; the control unit controls the alternating operation of the dual-chamber parallel hoppers.

[0008] This device integrates the feeding system, discharging system, and monitoring system. Relying on the control unit to precisely control the alternating "one-on-one" operation of the dual-chamber parallel locking bucket, it can achieve high-pressure feeding of fine powder without stopping the reactor or depressurizing, and ensure quasi-continuous discharge of solid products. At the same time, through real-time monitoring and regulation by multiple sensors, it effectively reduces pressure fluctuations in the supercritical reactor, taking into account the continuity of the reaction, product stability, and operational safety. It is suitable for the high-efficiency operation requirements of high-pressure reaction scenarios such as supercritical water reduction of metal oxides.

[0009] Preferably, the feed hopper includes a hopper cover, an air inlet, an air outlet, a hopper cavity, a pressure equalization branch, a pulse valve, a spring-loaded back pressure valve, and a porous diffusion nozzle; the pressure equalization branch is connected to the supercritical reactor; the powder enters the supercritical reactor through the porous diffusion nozzle. The spring-loaded back pressure valve, in conjunction with the pressure equalization branch, ensures precise matching between the pressure inside the feed hopper and the pressure in the supercritical reactor, preventing interruption of powder delivery or impact on the reaction system due to pressure differences; while the pulse valve, in conjunction with the porous diffusion nozzle, stably pushes fine powder, achieving uniform injection.

[0010] More preferably, the aperture of the porous diffusion nozzle is 50μm-150μm, and the ratio of the nozzle length to the aperture is 6-12. This aperture is suitable for fine powder (particle size ≤100μm), which can prevent powder from clogging the nozzle; the controlled aspect ratio can form a stable diffusion flow, preventing jet or turbulence damage to particles during injection, while allowing the fine powder to be uniformly dispersed into the supercritical reactor, reducing local enrichment.

[0011] Preferably, the supercritical reactor includes a reactor cavity, a power supply, and an electrode assembly; the electrode assembly includes multiple electrodes fixed within the reactor cavity; when the output terminal of the power supply is a high-voltage terminal and a ground terminal, the number of electrodes is a positive integer multiple of 2; when the output terminal of the power supply is three-phase, the number of electrodes is a positive integer multiple of 3; the input terminal of each electrode is electrically connected to the output terminal of the power supply, and the electrode is configured to adjust the corresponding power supply parameters according to the power supply.

[0012] Preferably, the dual-chamber parallel locking hopper further includes a progressive pressure reducing valve, a back pressure / throttling unit, and an inert sweep line; when locking hopper A is connected to the supercritical reactor for feeding, locking hopper B first uses the progressive pressure reducing valve to steadily reduce the pressure from high pressure to medium pressure, then uses the back pressure / throttling unit to further reduce it to near atmospheric pressure, and finally the inert sweep line delivers the product to the transition vessel. Multi-stage pressure reduction can avoid product shock or oxidation caused by sudden pressure drops.

[0013] More preferably, the transition vessel is provided with an exhaust port and a scavenging nozzle; a filter unit is installed at the exhaust port; the scavenging nozzle sends the powder into the product collection chamber by swinging the air. The filter unit at the exhaust port can intercept fine dust entrained in the gas, preventing product loss and environmental pollutants.

[0014] More preferably, the discharge system is equipped with a circulating water condensation unit to control the temperature of the dual-cavity parallel lock hopper, the transition vessel, and the connecting pipe between the dual-cavity parallel lock hopper and the transition vessel to remain below 100°C. This design avoids excessive vaporization of residual moisture due to high temperatures, which could affect gas-solid separation, and also prevents excessively high temperatures from aggravating the oxidation of metal powder. Simultaneously, it ensures stable fluid flow within the pipeline, providing a suitable temperature environment for subsequent product transportation and recovery, thus facilitating a smooth and efficient discharge process.

[0015] Preferably, the product collection chamber includes a pressure control component for maintaining the pressure inside the chamber at 0.11 MPa; a solid-gas separation component for separating and collecting metal powder and residual moisture from the fluid; and an exhaust port, upstream of which a filter component is mounted. Maintaining a stable environment of 0.11 MPa prevents pressure fluctuations from disturbing powder deposition.

[0016] Preferably, it also includes an over-temperature / over-pressure interlock; the over-temperature / over-pressure interlock is configured such that when the temperature or pressure is too high, or when the throttling is abnormal, the monitoring system triggers the over-temperature / over-pressure interlock to cut off the feed, or switches the working state of the dual-chamber parallel lock hopper.

[0017] According to a second aspect of the present invention, a method for applying an integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor is provided, comprising the following steps: S1. Powder is fed into the feed lock hopper, and the pressure of the feed lock hopper is balanced with that of the supercritical reactor. S2. After the pressure is equalized, all the powder in the feed hopper is pushed into the supercritical reactor to start the reaction. S3. After the reaction is completed, the control unit switches the connection state of the dual-chamber parallel lock hoppers to send the reaction products into the transition vessel; when lock hopper A is connected to the supercritical reactor and disconnected from the transition vessel, lock hopper B is connected to the transition vessel and disconnected from the supercritical reactor; after lock hopper A is fed and lock hopper B is discharged, the system switches to lock hopper B connected to the supercritical reactor and lock hopper A connected to the transition vessel, realizing alternating operation; S4. The reaction product is subjected to gas-solid separation in the transition vessel, and the dried solid powder is sent to the product collection chamber for recovery under the protection of inert gas.

[0018] Compared with the prior art, this application has the following beneficial effects: (1) The feed side of the integrated device for high-pressure feeding of fine powder and solid discharge based on supercritical reactor of this application adopts the design of "lock hopper-pressure equalization-pulse propulsion-porous diffusion". Pressure equalization through lock hopper avoids pressure shock, and pulse propulsion combined with porous diffusion ensures uniform injection of fine powder. It does not require stopping the machine to release pressure, thus solving the production interruption problem of traditional open-top filling, and also prevents fine powder agglomeration and blockage, providing a stable raw material supply for the continuous operation of supercritical reaction.

[0019] (2) The fine powder high-pressure feeding and solid discharge integrated device based on supercritical reactor of this application relies on the "dual-chamber parallel lock bucket - gradual pressure reduction - condensation recovery - inert sweep line - re-equalization" cycle mode on the discharge side. The dual-chamber lock bucket alternately operates to achieve continuous discharge. Gradual pressure reduction and condensation recovery avoid sudden pressure drop that leads to product oxidation. Inert sweep line ensures thorough solid conveying. Re-equalization maintains stable system pressure, effectively reducing product loss and improving the purity of metal products and discharge efficiency.

[0020] (3) The feed side and discharge side of the integrated device for fine powder high pressure feeding and solid discharge based on supercritical reactor of this application cooperate with each other, and combined with integrated monitoring and protection, it can accurately maintain the temperature and pressure environment required for supercritical reaction, suppress pressure fluctuation of supercritical reactor, solve the pain point of difficult control of existing technical parameters, and reduce the risk of device failure through anti-blocking and anti-oxidation design, ensuring stable and reliable operation of the whole process. Attached Figure Description

[0021] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of this application. Other embodiments and many anticipated advantages of these embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0022] Figure 1 A schematic diagram of an integrated device for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor according to an embodiment of this application is shown. Figure 2 A cross-sectional schematic diagram of the feed lock hopper of an integrated device for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor according to an embodiment of this application is shown. Figure 3 A schematic diagram of the application process of an integrated device for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor, according to an embodiment of this application, is shown. Figure 4 A photograph of Fe-Cu alloy nanopowder prepared according to an embodiment of this application is shown. Figure 5 SEM images of Fe-Cu alloy nanopowder prepared according to an embodiment of this application are shown; Figure 6 The XRD pattern of elemental Fe is shown. Figure 7 The XRD pattern of elemental Cu is shown. Figure 8 The XRD pattern of Fe-Cu alloy nanopowder prepared according to an embodiment of this application is shown.

[0023] The attached figures are labeled as follows: 1-Feed hopper, 101-hopper cover, 102-air inlet, 103-air outlet, 104-hopper cavity, 105-feed valve, 106-pulse valve, 107-spring-type back pressure valve, 108-porous diffusion nozzle, 2-supercritical reactor, 3-hopper A, 4-hopper B, 5-transition vessel, 501-exhaust port, 502-scavenging nozzle, 6-product collection chamber, 601-exhaust hole. Detailed Implementation

[0024] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0025] Where there is no conflict, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] Figure 1 This diagram shows an overall system schematic of an integrated device for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor according to the present invention. (Refer to...) Figure 1 The device includes a feeding system, a discharging system, and a monitoring system.

[0027] Specifically, the feeding system includes a feeding lock hopper 1 and a supercritical reactor 2; the discharging system includes a dual-chamber parallel lock hopper, a transition vessel 5, and a product collection chamber 6; and the monitoring system includes a pressure sensor, a temperature sensor, a differential pressure sensor, and a control unit.

[0028] Specifically, the feed hopper 1 includes a hopper cover 101, an air inlet 102, an air outlet 103, a hopper cavity 104, a feed valve 105, a pulse valve 106, a spring-loaded back pressure valve 107, and a porous diffusion nozzle 108, such as... Figure 2 As shown. With the feed valve 105 open, the feed lock hopper can be fed. After feeding is completed and the air inside the lock hopper cavity 104 is discharged, the feed valve 105 can be closed. The pulse valve 106 cooperates with the porous diffusion nozzle 108 to achieve stable pushing and uniform injection of powder.

[0029] Specifically, the feed lock hopper 1 also includes a pressure equalization branch (±0.05MPa). The feed lock hopper 1 can achieve pressure equalization with the supercritical reactor 2 through the pressure equalization branch and the spring-loaded back pressure valve 107 to ensure the stability of the pressure during the feeding process.

[0030] In a specific embodiment, the volume of the locking chamber 104 is 60-120 cm³. 3Each batch can feed 50g (powder particle size ≤100μm); the inert gas (such as N2 or Ar) supply to pulse valve 106 is 0.5-1NL. min -1 The orifice diameter of the porous diffusion nozzle 108 is 50μm-150μm, and the ratio of nozzle length to orifice diameter is 6-12.

[0031] Specifically, the supercritical reactor 2 includes a reactor cavity, a power supply, and an electrode assembly; the electrode assembly includes multiple electrodes fixed in the reactor cavity; when the output terminal of the power supply is a high-voltage terminal and a ground terminal, the number of electrodes is a positive integer multiple of 2; when the output terminal of the power supply is three-phase, the number of electrodes is a positive integer multiple of 3; the input terminal of each electrode is electrically connected to the output terminal of the power supply, and the electrodes are configured to adjust the corresponding power supply parameters according to the power supply.

[0032] In a specific embodiment, supercritical water discharge generates H... The optimal parameters are as follows: temperature 385-405℃, pressure 22-30MPa, to ensure that water is in a supercritical state and prolong the H+ period. Lifespan down to the microsecond to millisecond level; discharge power suitable 10 J / pulse, pulse duration 1 μs, voltage 5-20 kV, current intensity 10-100 A, frequency 10-100 kHz, adjusted according to the reaction scale to achieve H Concentrations reaching 10⁻⁵–10⁻³ mol / L promote reduction reactions (such as H₂). +MO→H2O+M) and inhibit oxidation, while controlling the oxygen ratio. 0.2 to maximize H2 production.

[0033] Specifically, the dual-chamber parallel lock hopper includes lock hopper A3, lock hopper B4, a progressive pressure reducing valve, a back pressure / throttling unit, and an inertial sweep line. When lock hopper A3 is connected to the supercritical reactor 2 for feeding and disconnected from the transition reactor 5, lock hopper B4 first uses the progressive pressure reducing valve to steadily reduce the pressure from high pressure to medium pressure, and then further reduces it to near atmospheric pressure through the back pressure / throttling unit. During this process, the inertial sweep line continues to work, using inert gas to push the product to the transition reactor 5, while preventing the product from re-oxidizing or absorbing moisture. After lock hopper A3 completes feeding and lock hopper B4 completes discharging, the monitoring system automatically controls the switching state, connecting lock hopper B4 to the supercritical reactor 2 for feeding, and lock hopper A3 to the transition reactor 5 to prepare for the next discharge, realizing the alternating and efficient operation of the dual-chamber parallel lock hoppers.

[0034] Specifically, the transition vessel 5 is equipped with an exhaust port 501, a scavenging nozzle 502, and a pressure regulating valve. The exhaust port 501 is equipped with a filter unit, which can effectively intercept the fine dust entrained in the gas, avoiding product loss and environmental pollution. The scavenging nozzle 502 delivers the powder evenly and stably into the product collection chamber 6 by swinging the air to ensure the thoroughness and continuity of powder delivery. The pressure regulating valve is used to precisely control the pressure in the transition vessel 5, keeping it within a suitable range to ensure the gas-solid separation effect and the stability of the subsequent delivery process.

[0035] Specifically, the discharge system is equipped with a circulating water condensation unit.

[0036] In a specific embodiment, the outer shell or connecting pipe of the dual-cavity parallel lock hopper is equipped with a cooling jacket, and the outer shell of the transition vessel 5 is also equipped with a cooling structure. The circulating water condensation unit controls the temperature of the dual-cavity parallel lock hopper, the transition vessel 5, and the connecting pipe between them stably below 100°C by circulating cooling water into the cooling jacket and the cooling structure of the transition vessel 5. This temperature control range can, on the one hand, prevent excessive vaporization of residual moisture due to high temperature, avoid the escape of water vapor carrying fine powder, affecting the gas-solid separation effect, and causing product loss; on the other hand, it can suppress the oxidation of metal powder caused by excessive temperature, ensure the purity and quality of metal products, and maintain the stable physical state of the fluid in the pipeline, ensuring smooth fluid flow. This creates a suitable temperature environment for the subsequent transport and recovery of products from the transition vessel to the product collection chamber, making the entire discharge process smoother and more efficient.

[0037] Specifically, the product collection chamber 6 includes a pressure control component for maintaining the pressure inside the product collection chamber at 0.11 MPa; a solid-gas separation component for separating and collecting metal powder and residual moisture in the fluid; and an exhaust port 601, with a filter component mounted upstream of the exhaust port 601.

[0038] In a specific embodiment, the air pressure control component is a ball valve; the solid-gas separation component is a collection bag, which can separate and collect metal powder and residual moisture in the fluid.

[0039] In a specific embodiment, the filtration unit inside the transition vessel 5 and the filtration assembly in the product collection chamber 6 are both HEPA filtration units.

[0040] In other embodiments, the device is also equipped with an anti-clogging unit, such as a periodic pulse backflushing device, which is automatically controlled by the control system to inject nitrogen into the pipeline for a short time (1-2 seconds) at regular intervals. The reverse impact force generated by the gas pulse disperses and carries away the metal particles attached to the pipe wall or valve, preventing accumulation and blockage. A pre-filter can also be set upstream of the HEPA filter unit to intercept larger metal particles first, reducing the amount of particles entering the downstream fine pipe or valve, thus reducing the risk of blockage from the source.

[0041] Specifically, the control unit, as the "brain" of the monitoring system, receives real-time data from all sensors (including pressure sensors, temperature sensors, and differential pressure sensors, etc.), makes logical judgments against preset safety and process parameters, and generates control commands.

[0042] In a specific embodiment, the control unit is a PLC. The PLC achieves automated control through a closed-loop process of "real-time acquisition - logical judgment - precise control". The controlled objects include: the switching of the dual-chamber parallel lock hopper, the opening and closing actions of valves such as the feed valve 105, spring-type back pressure valve, pulse valve, progressive pressure reducing valve, temperature control valve of the circulating water condensation unit and over-temperature / over-pressure interlock shut-off valve, the opening degree of the back pressure / throttling unit, and the amount of sweeping gas.

[0043] In specific embodiments, valves (such as progressive pressure reducing valves, spring-loaded back pressure valves, etc.) and cavities (such as supercritical reactor cavities, dual-cavity parallel lock hopper cavities, transition vessel cavities, etc.) that come into direct contact with supercritical water are made of materials such as Hastelloy C-276, Hastelloy 625, titanium alloys, 310S stainless steel, and tungsten-titanium alloys.

[0044] Figure 3 This is a schematic diagram of the application process of the integrated fine powder high-pressure feeding and solid discharge device based on a supercritical reactor, for reference. Figure 3 The specific steps are as follows: S1. Feed powder into feed lock hopper 1 and equalize the pressure of feed lock hopper 1 with that of supercritical reactor 2; S2. After the pressure is balanced, all the powder in the feed hopper 1 is pushed into the supercritical reactor 2 to start the reaction. S3. After the reaction is completed, the control unit switches the connection state of the dual-chamber parallel lock buckets to send the reaction products into the transition vessel 5. When lock bucket A3 is connected to the supercritical reactor 2 and disconnected from the transition vessel 5, lock bucket B4 is connected to the transition vessel 5 and disconnected from the supercritical reactor 2. After lock bucket A3 is fed and lock bucket B4 is discharged, the system switches to lock bucket B4 connected to the supercritical reactor 2 and lock bucket A3 connected to the transition vessel 5 to achieve alternating operation. S4. The reaction product is subjected to gas-solid separation in the transition vessel 5. The dried solid powder is sent to the product collection chamber 6 for recovery under the protection of inert gas.

[0045] Example 1 The specific steps for preparing Fe nanopowder by supercritical water reduction of Fe2O3 fine powder are as follows: S101. With the spring-pressed valve and pulse valve closed, open the hopper cover 101 and feed valve 105 of the feed hopper 1, and put the mixed powder of 50g Fe2O3 fine powder (150 mesh) and 27.4g copper oxide fine powder (100 mesh) into the hopper chamber 104; after tightening the hopper cover 101, inject nitrogen gas into the air inlet 102 at a rate of 0.1L / min, and at the same time open the air outlet 103 to expel the air in the chamber. After 1 minute, close the air outlet 103 and feed valve 105 respectively; when the pressure in the hopper chamber 104 is 25.5MPa, the device automatically closes the air inlet 102.

[0046] S102. After the pressure inside the supercritical reactor 2 reaches 25 MPa and the temperature reaches 385℃ and the parameters stabilize, open the pulse valve 106 (frequency 15 times / min) and the spring-type back pressure valve 107 to equalize the pressure in the lock chamber 104 to 25 MPa ± 0.05 MPa. Under the nitrogen thrust of the pulse valve 106, the mixed powder is uniformly injected into the supercritical reactor 2 through the porous diffusion nozzle 108. After the powder in the lock chamber 104 is completely conveyed, close the pulse valve 106 and the spring-type back pressure valve 107 to maintain the supercritical reactor 2 at 25 MPa and 385℃ for 5 minutes of reduction reaction.

[0047] S103. After the reaction is complete, the PLC controls the corresponding lock hopper (e.g., lock hopper A3) in the dual-chamber parallel lock hopper to connect with the supercritical reactor 2, and the supercritical aqueous solution containing Fe-Cu alloy powder enters the lock hopper. The progressive pressure reduction valve is activated, and closed-loop control is achieved through feedback from the upstream pressure sensor: the servo motor adjusts the valve opening at a rate of ΔP / Δt = 6 bar / s, smoothly reducing the fluid pressure from 25 MPa to 12 MPa. During this period, the valve opening linearly increases from 0% to 50%, controlling the fluid flow rate to remain at 5-9 L / h to avoid sudden expansion leading to phase separation or alloy powder deposition. After the fluid enters the medium-pressure to low-pressure stage, the back pressure / throttling unit takes over the control: the PLC dynamically adjusts the reference pressure of the back pressure valve (using an Equilibar type floating diaphragm sealing orifice) to ensure a stable upstream back pressure of 5 MPa, allowing the fluid to flow out in a stable state to near atmospheric pressure. The entire pressure reduction and outflow process is precisely controlled within 40 seconds to avoid... The rapid pressure drop of 10 seconds leads to uneven condensation, ensuring the dispersion of the alloy powder. During the pressure reduction process, the anti-clogging unit is activated simultaneously: the PLC triggers nitrogen pulse backflushing at a preset frequency (1-2 seconds each time), working in conjunction with the upstream HEPA pre-filter to prevent metal particles from depositing and clogging in pipelines or valves.

[0048] S104. The alloy powder-containing fluid (pressure 10-20 bar, partially vaporized) after pressure reduction in S103 enters the transition vessel 5. The circulating water condensation unit is activated, and circulating water is introduced into the jacket of the transition vessel 5 to stabilize the temperature inside the chamber below 100℃ (80-100℃ in a specific embodiment). Simultaneously, the pressure regulating valve and filter unit at the exhaust port 501 of the transition vessel 5 are opened: the pressure regulating valve adjusts the pressure inside the transition vessel 5 to 0.15-0.2MPa based on feedback from the pressure sensor to ensure pressure stability; the filter unit is responsible for intercepting Fe-Cu alloy micro-powder entrained in the gas to prevent it from being lost with the airflow. After the fluid has settled in the transition vessel 5, the scavenging nozzle 502 at the bottom of the transition vessel 5 is activated to introduce inert gas and perform scavenging at a preset frequency, using the gas thrust to uniformly push the alloy powder deposited at the bottom of the vessel to the product collection chamber 6.

[0049] S105. After the alloy powder enters the product collection chamber 6 with the inert gas, the ball valve inside is opened. The valve opening is adjusted based on pressure sensor feedback to maintain the pressure inside the collection chamber at a stable 0.11 MPa, preventing pressure fluctuations from disturbing powder deposition. During collection, the gas carries the alloy powder and residual moisture through the internal collection bag. The collection bag intercepts the alloy powder and moisture, while the gas passes through the bag and is discharged through the exhaust port 601. Before discharge, the gas is filtered again by the upstream HEPA filter assembly to ensure no residual microparticles remain in the gas. After a single discharge cycle is completed, the inlet valve of the product collection chamber 6 is closed, the collection bag is removed, and the collection bag is dried to remove residual moisture, thus obtaining Fe-Cu alloy nanoparticles.

[0050] The prepared Fe-Cu alloy nanopowder physical object is shown below. Figure 4 As shown, the SEM image of the Fe-Cu alloy grains is as follows: Figure 5 As shown, from Figure 5 The SEM images clearly show that the Fe-Cu alloy grains exhibit a uniform and fine nanoscale structure with a narrow grain size distribution. This fine microstructure indicates that during the supercritical water reduction process, the Fe₂O₃ fine powder and copper oxide fine powder achieved an efficient reduction and alloying reaction, forming a uniform Fe-Cu alloy phase. Simultaneously, the supercritical water environment effectively suppressed excessive grain growth and agglomeration, resulting in a final product with a high specific surface area and good dispersibility. These characteristics are of great significance for improving the application performance of Fe-Cu alloy nanopowder in catalysis, magnetic materials, and other fields.

[0051] Figures 6-8 The images show the XRD patterns of Fe, Cu, and Fe-Cu alloys, respectively. Figure 6As can be seen, the diffraction peaks appear near 2θ = 43.54°, 50.58°, 74.59°, and 89.86°, corresponding to the (111), (200), (220), and (311) crystal planes of the γ-Fe crystal, respectively. From... Figure 7 As can be seen, characteristic diffraction peaks belonging to Cu element appear near 2θ = 36.53°, 43.34°, and 50.12°, corresponding to the (110), (200), and (211) crystal planes, respectively. From... Figure 8 As can be seen from the XRD pattern, the Fe-Cu alloy contains characteristic diffraction peaks of both Fe and Cu. This indicates that the high-temperature and high-pressure reduction environment of the supercritical reactor successfully prepared the Fe-Cu alloy with excellent uniformity, fully verifying the technological superiority of this device in the preparation of special phases, phase transformation control, and alloying reactions.

[0052] The specific embodiments of this application have been described above, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0053] In the description of this application, it should be understood that the terms "upper," "lower," "inner," "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that combinations of these measures cannot be used for improvement. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. An integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor, characterized in that, The system includes a feeding system, a discharging system, and a monitoring system. The feeding system includes a feeding hopper and a supercritical reactor. The discharging system includes a dual-chamber parallel hopper, a transition vessel, and a product collection chamber. The monitoring system includes a pressure sensor, a temperature sensor, a differential pressure sensor, and a control unit. The dual-chamber parallel hopper includes hopper A and hopper B. When hopper A is connected to the supercritical reactor and disconnected from the transition vessel, hopper B is connected to the transition vessel and disconnected from the supercritical reactor. The control unit controls the alternating operation of the dual-chamber parallel hoppers.

2. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 1, characterized in that, The feed hopper includes a hopper cover, an air inlet, an air outlet, a hopper cavity, a pressure equalization branch, a pulse valve, a spring-loaded back pressure valve, and a porous diffusion nozzle; the pressure equalization branch is connected to the supercritical reactor; the powder enters the supercritical reactor through the porous diffusion nozzle.

3. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 2, characterized in that, The aperture of the porous diffusion nozzle is 50μm-150μm, and the ratio of the nozzle length to the aperture is 6-12.

4. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 1, characterized in that, The supercritical reactor includes a reactor cavity, a power supply, and an electrode assembly. The electrode assembly includes multiple electrodes fixed within the reactor cavity. When the output terminal of the power supply is a high-voltage terminal and a ground terminal, the number of electrodes is a positive integer multiple of 2. When the output terminal of the power supply is three-phase, the number of electrodes is a positive integer multiple of 3. The input terminal of each electrode is electrically connected to the output terminal of the power supply, and the electrode is configured to adjust the corresponding power supply parameters according to the power supply.

5. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 1, characterized in that, The dual-chamber parallel lock hopper also includes a progressive pressure reducing valve, a back pressure / throttling unit, and an inert sweep line; when the lock hopper A is connected to the supercritical reactor for feeding, the lock hopper B first uses the progressive pressure reducing valve to steadily reduce the pressure from high pressure to medium pressure, then uses the back pressure / throttling unit to further reduce it to near atmospheric pressure, and finally the inert sweep line sends the product to the transition vessel.

6. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 5, characterized in that, The transition vessel is equipped with an exhaust port and a scavenging nozzle; A filter unit is installed at the exhaust port; the scavenging nozzle sends the powder into the product collection chamber by swinging the scavenging nozzle.

7. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 6, characterized in that, The discharge system is equipped with a circulating water condensation unit to control the temperature of the dual-cavity parallel lock hopper, the transition vessel, and the connecting pipe between the dual-cavity parallel lock hopper and the transition vessel to remain below 100°C.

8. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 1, characterized in that, The product collection chamber includes a pressure control component for maintaining the pressure inside the product collection chamber at 0.11 MPa; Solid-gas separation unit, used to separate and collect metal powder and residual moisture in fluid; And an exhaust port, with a filter assembly mounted upstream of the exhaust port.

9. The integrated device for high-pressure feeding of fine powder and discharge of solids based on a supercritical reactor according to claim 1, characterized in that, It also includes an over-temperature / over-pressure interlock; the over-temperature / over-pressure interlock is configured so that when the temperature or pressure is too high, or when the throttling is abnormal, the monitoring system triggers the over-temperature / over-pressure interlock to cut off the feed, or switches the working state of the dual-chamber parallel lock hopper.

10. An application method of an integrated device for high-pressure feeding of fine powder and solid discharge based on a supercritical reactor as described in any one of claims 1-9, characterized in that, Includes the following steps: S1. Powder is fed into the feed lock hopper, and the pressure of the feed lock hopper is balanced with that of the supercritical reactor. S2. After the pressure is equalized, all the powder in the feed hopper is pushed into the supercritical reactor to start the reaction. S3. After the reaction is completed, the control unit switches the connection state of the dual-chamber parallel lock hoppers to send the reaction products into the transition vessel; when lock hopper A is connected to the supercritical reactor and disconnected from the transition vessel, lock hopper B is connected to the transition vessel and disconnected from the supercritical reactor; after lock hopper A is fed and lock hopper B is discharged, the system switches to lock hopper B connected to the supercritical reactor and lock hopper A connected to the transition vessel, realizing alternating operation; S4. The reaction product is subjected to gas-solid separation in the transition vessel, and the dried solid powder is sent to the product collection chamber for recovery under the protection of inert gas.

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