An integrated photocatalytic hydrogen production device and method based on parallel whirl reaction and in-situ purification

Abstract

The application provides an integrated photocatalytic hydrogen production device and method based on parallel vortex reaction and in-situ purification, and relates to the technical field of hydrogen production. The device comprises a double-branch flow feeding unit, a parallel vortex reaction unit, a light source introduction unit and a product collection and circulation unit. The vortex reactor is provided with a tangential feeding port, a top overflow port and a bottom underflow port; the feeding unit is communicated with the tangential feeding port through parallel pipelines designed according to the double-branch flow theory; the light guide rod of the light source introduction unit extends into the reactor; the product collection unit is respectively communicated with the top overflow port and the underflow port through pipelines, and the underflow port is connected to the total feeding pipe through a circulation pipeline. The application utilizes the vortex field to strengthen mass transfer and in-situ gas-liquid separation, combines the double-branch flow theory to realize uniform distribution of multiple reactors, realizes the integration of reaction, separation and circulation, and has the advantages of large processing flux, high light energy utilization rate and good operation flexibility.

Description

Technical Field

[0001] This invention relates to the field of hydrogen production technology, and in particular to an integrated photocatalytic hydrogen production device and method based on parallel swirling reaction and in-situ purification. Background Technology

[0002] Hydrogen energy, as a clean energy source with high calorific value and zero carbon emissions, is considered a key carrier for the transformation of the future energy structure. Among various hydrogen production technologies, photocatalytic water splitting technology driven by solar energy is regarded as a highly promising and ideal technology route due to its outstanding advantages such as directly converting solar energy into chemical energy, green and environmentally friendly process, and mild reaction conditions.

[0003] The core of this technology's practical application lies in developing a highly efficient, stable, and cost-effective photocatalytic reaction system. Existing technologies have undergone numerous improvements in areas such as light energy enhancement, product separation, catalyst immobilization, and system integration. CN101973519B improves light energy utilization efficiency through a concentrated-converted light composite method, but its reactor is a static or simple flow tank structure with limited mixing intensity, and product separation depends on external membrane modules; CN111453696B uses a composite parabolic concentrator and a fixed-bed supported catalyst, which avoids catalyst separation and recovery, but the fixed bed has high mass transfer resistance, and the contact efficiency between reactants and catalyst is limited.

[0004] CN111874864B dilutes the products with argon gas and controls the hydrogen concentration using a membrane separation system, but the system has high energy consumption and does not address in-reactor mixing enhancement. CN104226224B integrates gas collection, metering, and detection devices, but the reactor is a conventional stirred tank reactor, which struggles to solve mixing, mass transfer, and in-situ product separation issues during large-scale scale-up. CN111056528B improves reaction efficiency through a floating interface structure, but its processing capacity is limited by the interface area, making large-scale continuous flow processing difficult. CN114644320B simplifies reaction conditions through innovative catalytic materials, but does not address reactor engineering design and optimization. CN113952908B employs a Z-type dual-reactor system with integrated thermoelectric power generation, but the reaction and separation processes are independent, resulting in a complex system structure. CN114873559B, CN115514293A, CN119390013A, CN119934698A, CN120174392A, CN117285004B, and CN117504773A improve upon these technologies by addressing aspects such as spectral utilization, functional switching, focused reflection, external field control, photoelectric coupling, and extending the reaction path. However, most of these improvements fail to address the issues of multiphase flow mixing, mass transfer, and in-situ product removal within the reactor. CN119368100A achieves scale expansion through multi-reaction device integration, while CN117963840A achieves hydrogen production regulation through multiple parallel membrane reactor sub-modules. However, both offer limited improvement in hydrogen enrichment and separation efficiency within a single reaction unit.

[0005] In summary, existing photocatalytic hydrogen production technologies and devices still have the following prominent problems: 1) Separation of reaction and separation processes: In most systems, the reaction and product separation are carried out independently, and hydrogen has a long residence time in the liquid phase, requiring additional separation units and making the system complex; 2) Difficulty in scaling up: Traditional parallel methods are prone to uneven feeding and large differences in operating conditions among units; 3) Challenges in catalyst recovery and recycling: Powdered catalysts are difficult to separate, while immobilized catalysts face problems of limited mass transfer and few active sites; 4) Insufficient synergistic enhancement of multiple fields and system integration: The synergy of light field, flow field and concentration field in the reactor is insufficient, and there is a lack of compact systems that integrate efficient mixing, in-situ separation, catalyst circulation and uniform flow scale-up.

[0006] Therefore, developing an integrated photocatalytic hydrogen production device and method that can synergistically solve the core contradictions such as reaction-separation coupling, scale-up and flow equalization, catalyst circulation, and multi-field synergistic enhancement is of great significance for promoting the engineering application of this technology. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to overcome the shortcomings of the prior art and provide an integrated photocatalytic hydrogen production device and method based on parallel swirling reaction and in-situ purification. By integrating the photocatalytic reaction and product separation process into one, and introducing specific flow field enhancement and distribution theories, high-efficiency, high-stability, and easily scalable photocatalytic hydrogen production can be achieved.

[0008] This invention provides the following technical solution: In a first aspect, embodiments of this application provide an integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification. The device includes a dual-branch feed unit, a parallel swirling reaction unit, a light source introduction unit, and a product collection and recycling unit, wherein: The dual-branch flow feeding unit includes a main feed pipe and multiple parallel pipes; The parallel swirl reactor unit includes multiple swirl reactors arranged in parallel. Each swirl reactor has a tangential feed inlet, a top overflow inlet, and a bottom underflow inlet. Each tangential feed inlet is connected to the main feed pipe through a corresponding parallel pipeline. The light source introduction unit includes an external light source and a built-in light guide rod, the built-in light guide rod extending into the internal reaction zone of each of the swirling reactors; The product collection and circulation unit includes a hydrogen collection main pipe and a catalyst slurry circulation pipeline. The hydrogen collection main pipe is connected to the top overflow port of each of the cyclone reactors. One end of the catalyst slurry circulation pipeline is connected to the bottom underflow port of each of the cyclone reactors, and the other end is connected to the main feed pipe.

[0009] The embodiments of the present invention have the following advantages: The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification provided by this invention integrates the photocatalytic hydrogen production reaction and product separation process into the same equipment unit and completes them synchronously, realizing in-situ instant separation. This not only simplifies the process and equipment, but also improves the reaction rate and hydrogen production efficiency by reducing product retention.

[0010] The unique swirling field design not only enhances mass transfer mixing, but also promotes microscopic lattice distortion in the catalyst through shear force field, thereby improving catalytic performance.

[0011] The design of parallel pipelines is guided by the dual-branch flow theory, which ensures the uniform distribution of flow rate and pressure drop when multiple reactors are connected in parallel. This effectively overcomes the problems of uneven flow field and reduced efficiency that exist in simple scale-up, and provides a theoretical guarantee for the stable, efficient and large-scale operation of the system.

[0012] The device integrates four major functions: light introduction, reaction, separation, and circulation, and has a compact structure. It adopts a modular parallel design, which makes the processing capacity easy to adjust, and can be adapted to different spatial layouts by changing the connection method, thus having extremely high operational flexibility and engineering adaptability.

[0013] This achieves efficient catalyst recycling and reuse, reducing catalyst consumption and operating costs. If organic wastewater is used as the reaction liquid, the dual goals of wastewater treatment and clean energy production can be achieved simultaneously, aligning with the principles of green and sustainable development.

[0014] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the overall structure of an integrated photocatalytic hydrogen production device in one embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the overall engineering layout of an integrated photocatalytic hydrogen production device in one embodiment of the present invention.

[0018] Figure 3 This is an enlarged schematic diagram of the structure of a cyclone reactor in one embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the reaction and separation process in a cyclone reactor according to one embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of various parallel connection methods in one embodiment of the present invention.

[0021] Figure 6 This is a schematic diagram of the main feed pipe control body in one embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of the slurry circulation pipeline control body in one embodiment of the present invention; Figure 8 This is a flowchart illustrating the principle of an integrated photocatalytic hydrogen production method in one embodiment of the present invention.

[0023] Explanation of key component symbols: 1-Dual-branch feed unit; 2-Parallel swirl reaction unit; 3-Light source introduction unit; 4-Product collection and circulation unit; 11-Slurry buffer tank; 12-Feed pump; 13-Main feed pipe; 14-Vent pipe; 21-Tangential feed inlet; 22-Top overflow port; 23-Top overflow port flange; 24-Nut; 25-Bolt; 26-Underflow port flange; 27-Bottom underflow port; 28-Cylinder body; 29-Flow meter; 210-Pressure gauge; 211-First conical structure; 212-Second conical structure; 41-Hydrogen collection main pipe; 42-Catalyst slurry circulation pipeline. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0025] like Figures 1 to 5 As shown, in order to solve the above-mentioned technical problems, this application provides an integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification. The device includes a dual-branch feed unit 1, a parallel swirling reaction unit 2, a light source introduction unit 3, and a product collection and circulation unit 4, wherein: The dual-branch feed unit 1 includes a main feed pipe 13 and several parallel pipes. The main feed pipe 13 is connected to an external storage tank, through which an aqueous slurry containing a photocatalyst flows. To ensure uniform flow distribution in each parallel branch, each parallel pipe is equipped with a fine-tuning flow control valve and an online flow meter 29. Guided by the dual-branch theory, the flow deviation of each branch can be controlled within the design requirements, effectively overcoming the flow deviation problem in traditional parallel systems and achieving consistent operating conditions during large-scale scaling.

[0026] The parallel swirl reactor unit 2 is composed of multiple swirl reactors with identical structures connected in parallel. Each swirl reactor has a tangential feed inlet 21 on its side wall, a top overflow outlet at the top, and a bottom outlet at the bottom.

[0027] When the catalyst slurry enters the reactor through the tangential feed inlet 21 at a set linear velocity, a strong swirling flow field is formed under the action of centrifugal force. The heavy phase (liquid phase containing catalyst particles) is thrown against the reactor wall and moves downward along the cone surface, exiting from the bottom outlet; the light phase (gas-liquid mixture containing hydrogen) converges towards the central low-pressure zone and exits upward from the top overflow outlet 22. This process achieves the coupling of reaction with in-situ separation of the gas-solid-liquid three phases: on the one hand, the swirling flow enhances the turbulent contact between the catalyst particles and the reaction liquid, improving mass transfer efficiency; on the other hand, the generated hydrogen bubbles rapidly float and are removed in the centrifugal field, avoiding prolonged retention in the liquid phase; and the generated shear stress can act on the catalyst particles, inducing stress, strain, and even distortion in their crystal lattice at the microscopic level. This structural change has been proven to be beneficial to the separation and migration of photogenerated carriers, thereby fundamentally improving the intrinsic activity of the photocatalytic hydrogen evolution reaction.

[0028] The light source introduction unit 3 includes an external high-power LED array light source and multiple quartz built-in light guide rods. One end of each light guide rod is coupled to the output end of the light source, and the other end is vertically inserted into the central axis position of the corresponding swirling reactor, extending deep into the middle of the reaction zone.

[0029] The light guide rod is made of high-transmittance fused silica, and its outer surface is frosted to enhance lateral scattering, so that the ultraviolet light is radially radiated in the reactor, which can improve the uniformity of light intensity distribution in the reactor, effectively alleviate the light shielding effect, and improve the photon utilization rate.

[0030] The product collection and circulation unit 4 includes a hydrogen collection main pipe 41 and a catalyst slurry circulation pipeline 42.

[0031] The hydrogen collection manifold 41 is connected to the top overflow port 22 of each cyclone reactor via pipes. The top overflow port releases a gaseous product mainly composed of hydrogen or a hydrogen-rich fluid containing a small amount of liquid entrainment. In a preferred embodiment, the hydrogen-rich fluid is discharged through the hydrogen collection manifold 41 and dried before being collected as a hydrogen product. If necessary, the entrained droplets can be further removed by a gas-liquid separator.

[0032] The catalyst slurry circulation pipeline 42 collects the underflow from multiple outlets and then returns it to the main feed pipe 13 via a circulation pump, forming a closed-loop circulation. The circulation ratio is adjustable, which ensures high catalyst utilization while avoiding the operational complexity caused by frequent replenishment.

[0033] Clearly, the catalyst is always recycled within the system, eliminating the need for additional filtration or centrifugation equipment; at the same time, the swirling structure ensures a high suspension concentration and good dispersion of the catalyst in the reaction zone, overcoming the limitations of mass transfer in fixed beds.

[0034] In some embodiments, the dual-branch feed unit 1 further includes a slurry buffer tank 11 and a feed pump 12. The slurry buffer tank 11 is used to store catalyst slurry. The slurry buffer tank 11 is connected to the main feed pipe 13 through the feed pump 12. The feed pump 12 is used to pump the catalyst slurry in the slurry buffer tank 11 to the main feed pipe 13. A flow meter 29 and a regulating valve are provided on the parallel pipeline. The flow meter 29 is used to monitor the flow rate, and the regulating valve is used to regulate the flow rate.

[0035] In these embodiments, to further improve feeding stability and system controllability, the dual-branch feed unit 1 further includes a slurry buffer tank 11 and a feed pump 12.

[0036] The slurry buffer tank 11 is a closed container with a stirring function, with a volume of 5 to 200 L. The tank body is made of corrosion-resistant stainless steel or high-density polyethylene and is equipped with a liquid level sensor and a nitrogen protection interface to prevent slurry oxidation or water evaporation.

[0037] The slurry buffer tank 11 is connected to the inlet of the feed pump 12 via a pipeline, and the outlet of the feed pump 12 is connected to the main feed pipe 13. The flow rate of the feed pump 12 can be 5-50 m³ / s. 3 With precise adjustment within a range of / h and a pressure range of 0.1-1.0 MPa, it can stably and continuously deliver catalyst slurry to the downstream parallel pipeline system.

[0038] In addition, each parallel pipeline is equipped with a flow meter 29, a pressure gauge 210, and a regulating valve. The flow meter 29 monitors the slurry flow rate of each branch in real time; the regulating valve adjusts its opening to achieve dynamic flow balance among multiple channels, significantly improving the operational stability and amplification reliability of the parallel system.

[0039] For example, it also includes a vent pipe 14, which is connected to the bottom of the slurry buffer tank 11, for discharging residual material when the unit is shut down or under maintenance.

[0040] In some embodiments, the cyclone reactor includes a cylindrical body, a tangential feed inlet 21, a top overflow outlet, a bottom underflow outlet, a top overflow outlet flange 23, a bottom flow outlet flange 26, a nut 24, and a bolt 25; the tangential feed inlet 21 is disposed on the upper side wall of the cylindrical body and is used to introduce catalyst slurry and induce the formation of cyclone flow; The top overflow port is located at the center of the top along the axial direction of the cylinder, with its lower opening located in the central area of ​​the inner cavity of the cylinder and its upper end connected to the hydrogen collection main pipe 41.

[0041] In these embodiments, to further optimize the swirling flow field structure, improve the gas-liquid-solid three-phase separation efficiency and enhance the system's operational stability, each swirling reactor adopts a finely designed three-component integrated structure, specifically including: a cylinder 28, a top overflow flange 23, and a bottom flow flange 26.

[0042] The cylinder 28 is a cylindrical cavity made of highly transparent quartz glass or stainless steel lined with a high-reflectivity fluoropolymer. The inner wall of the cylinder is polished to reduce flow resistance and inhibit catalyst particle adhesion.

[0043] A top overflow flange 23 is located at the top of the cylinder 28, and a tangential feed port 21 and an upper top overflow port 22 are integrated thereon. The tangential feed port 21 is connected to the inner cavity of the cylinder 28, and its feed direction is tangential to the inner wall of the cylinder 28, so that the catalyst slurry forms a stable swirling field after entering the cylinder 28, thereby enhancing the slurry mixing and gas-liquid-solid three-phase contact, and promoting the enrichment of hydrogen bubbles in the central low-pressure area. The upper top overflow port 22 is located in the central area of ​​the top of the cylinder 28 and is connected to the hydrogen collection manifold 41, which is used to discharge the hydrogen enriched in the central low-pressure area in a timely manner.

[0044] The underflow flange 26 is located at the bottom of the cylinder 28 and has a bottom underflow port 27. The bottom underflow port 27 is connected to the bottom area of ​​the cylinder 28 and is used to discharge the liquid-solid slurry after the reaction and gas phase separation are completed. It is also convenient to connect to the subsequent circulation pipeline or discharge pipeline to maintain the material balance and continuous operation stability in the reactor.

[0045] In some embodiments, a first conical structure 211 is provided at the top of the cyclone reactor and a second conical structure 212 is provided at the bottom. The tips of the first conical structure 211 and the tips of the second conical structure 212 are arranged opposite to each other to form a double inner cone structure. The double inner cone structure is used to induce the gas phase to converge toward the central axis of the reactor to realize the hydrogen enrichment and separation process.

[0046] In some embodiments, the end or side of the built-in light guide is provided with an optical lens for focusing light; and / or, the external light source is sunlight or an artificial light source.

[0047] In these embodiments, to further improve the utilization efficiency of light energy inside the cyclone reactor, the optical output end of the built-in light guide is functionally enhanced. Specifically, micro-optical lenses are integrated at the end and / or sides of the built-in light guide.

[0048] The optical lens can be a convex lens, a Fresnel lens, or a gradient refractive index lens, and its material is compatible with the light guide rod substrate (such as fused silica or high-transmittance PMMA) and fixed to the surface of the light guide rod. When the light is transmitted along the light guide rod to the end or side wall, the optical lens focuses, collimates, or diverges the outgoing beam, thereby forming a high-intensity-density irradiation spot in the key reaction area of ​​the swirling reactor, effectively overcoming the light attenuation problem caused by light scattering or absorption.

[0049] In some embodiments, a flow control device is provided on the catalyst slurry circulation pipeline 42. The flow control device is a flow control valve with an inlet, a circulation outlet and a discharge outlet. The inlet is connected to the underflow port, the circulation outlet is connected to the main feed pipe 13, and the discharge outlet is connected to the outside.

[0050] In these embodiments, the inlet of the diversion control device is connected to the main pipeline after the underflow outlets of each cyclone reactor are collected, receiving slurry containing a high concentration of catalyst. The circulation outlet is connected to the main feed pipe 13 to achieve catalyst recycling. The discharge outlet is connected to an external collection or regeneration treatment unit for discharging part or all of the slurry.

[0051] For example, the flow divider valve can be a manually switched ball valve, a pneumatic three-way directional valve, or an electric proportional flow divider valve.

[0052] In some embodiments, the connection method between the feed main and the catalyst slurry circulation pipeline 42 is selected from at least one of the U1 type connection and the Z1 type connection: Among them, the U1 type connection is defined as follows: the flow direction of the catalyst slurry circulation pipeline 42 is opposite to the flow direction of the feed main pipe; Z1 type connection is defined as follows: the flow direction of the catalyst slurry circulation pipeline 42 is the same as the flow direction of the feed main pipe; The connection method between the feed main and the hydrogen collection main 41 is selected from at least one of the U2 type connection and the Z2 type connection: The U2 type connection is defined as follows: the flow direction of the hydrogen collection manifold 41 is opposite to that of the feed manifold.

[0053] Z2 type connection is defined as follows: the flow direction of the hydrogen collection main pipe 41 is the same as that of the feed main pipe; the connection method of multiple cyclone reactors is selected from one of the following arrangements: Type U1-U2: The feed main pipe and catalyst slurry circulation pipe 42 are connected in a U1 type, and the feed main pipe and hydrogen collection main pipe 41 are connected in a U2 type; Type U1-Z2: The feed main pipe and catalyst slurry circulation pipe 42 are connected in a U1 type, and the feed main pipe and hydrogen collection main pipe 41 are connected in a Z2 type; Type Z1-U2: The feed main pipe and catalyst slurry circulation pipe 42 are connected in a Z1 type, and the feed main pipe and hydrogen collection main pipe 41 are connected in a U1 type; Type Z1-Z2: The feed main pipe and catalyst slurry circulation pipe 42 are connected in a Z1 type, and the feed main pipe and hydrogen collection main pipe 41 are connected in a U1 type; The connections between pipes 42 are of type Z1, and the connection between the feed main pipe and the hydrogen collection main pipe 41 is of type Z2; U1-U2 and Z1-Z2 type: multiple cyclone reactors are divided into a first group and a second group. The cyclone reactors in the first group are arranged in type U1-U2, and the cyclone reactors in the second group are arranged in type Z1-Z2; Z1-Z2 and U1-U2 type: multiple cyclone reactors are divided into a first group and a second group. The cyclone reactors in the first group are arranged in type Z1-Z2, and the cyclone reactors in the second group are arranged in type U1-U2.

[0054] In these embodiments, in order to optimize the flow field symmetry, pressure drop balance and gas-liquid phase flow coordination in the parallel system of multi-swirling reactors, the present invention systematically designs the relative flow direction relationship between the feed main pipe and the catalyst slurry circulation pipeline 42, and between the feed main pipe and the hydrogen collection main pipe 41, and proposes a combined arrangement strategy based on "U-shaped" (reverse) and "Z-shaped" (same direction) connections.

[0055] The above flow directions are all based on the main flow direction of the system (e.g., from the slurry buffer tank 11, feed pump 12, feed main pipe, and cyclone reactor as the positive direction).

[0056] Based on the above definition, multiple cyclone reactors can be integrated using any of the following arrangements: U1-U2 type: Reverse reinjection of circulating slurry and reverse collection of hydrogen. This mode is suitable for long-distance pipeline layouts and can effectively offset the pressure gradient difference between the feed end and the return end, thereby reducing the pressure drop deviation of each parallel unit.

[0057] U1-Z2 type: The circulating slurry is reinjected in the reverse direction, and the hydrogen is collected in the same direction. This configuration is conducive to the rapid removal of hydrogen and reduces gas accumulation at the top, making it suitable for high hydrogen production rate conditions.

[0058] Z1-U2 type: Circulating slurry is reinjected in the same direction, while hydrogen is collected in the opposite direction. This method simplifies pipeline routing, reduces installation complexity, and is suitable for compact modular designs.

[0059] Z1-Z2 type: Both the circulating slurry and hydrogen flow in the same direction as the feed. This mode has the simplest flow field, is easy to automate, and is suitable for small demonstration systems.

[0060] U1-U2 and Z1-Z2 type: Multiple cyclone reactors are divided into two groups. The first group adopts the U1-U2 arrangement, and the second group adopts the Z1-Z2 arrangement. This mixing mode can balance the overall system resistance and is particularly suitable for large-scale arrays of more than 8 reactors. Actual measurements show a reduction in the standard deviation of flow rate of each unit.

[0061] Z1-Z2 and U1-U2 type: Symmetrical to the previous mode, the grouping strategy can be flexibly adjusted according to the site space or pipeline interface to improve the adaptability of the project.

[0062] The different structures described above do not change the reaction and separation principle of a single cyclone reactor. Instead, they adjust the friction resistance and local resistance of each branch by changing the spatial orientation, inlet and outlet positions and confluence sequence of the parallel pipelines. This allows each cyclone reactor to obtain closer feed flow rates, overflow exhaust resistance and underflow slurry discharge resistance, thereby improving the uniformity of flow distribution and the flexibility of engineering layout of the parallel system.

[0063] Figure 6 This is a schematic diagram of the main feed pipe control body in a preferred embodiment of the present invention. The mass conservation equation of the main feed pipe can be described by equation (1): (1) Among them, A i Let A be the cross-sectional area of ​​the main feed pipe at the i-th cyclone reactor location. c A d U represents the cross-sectional areas of the top overflow outlet and bottom outlet of the i-th cyclone reactor, respectively; i U is the axial velocity of the main feed pipe at the i-th cyclone reactor position. c U d denoted as , where is the axial velocity at the top overflow port and bottom flow port of the i-th cyclone reactor; X is the axial coordinate of the parallel cyclone reactor unit along the main feed pipe; ρ is the fluid density. Define α as the total flow split ratio of the parallel swirl reaction unit, which is equal to the ratio of the volumetric flow rate of the hydrogen collection manifold to that of the total feed manifold, as shown in equation (2): (2) Let ΔX = L / (n-1), where n is the number of parallel microcyclones and L is the total length of the feed tube. Thus, equation (1) can be simplified to equation (3): (3) Similarly, the momentum conservation equation can be described by equation (4): (4) Among them, P i Let D be the pressure at the location of the i-th cyclone reactor in the main feed pipe. iLet be the diameter of the main feed pipe at the i-th position in the cyclone reactor, and let τ be the shear stress. i Given by the Darcy–Weisbach formula, τ i =ρf i (U i 2 / 8); U cw =β c U i U dw =β d U i In the formula β c β d It is the axial velocity component U c U d The correction factors indicate the effect of the initial momentum change caused by inertial effects when some fluid enters or leaves the branch pipe. i The friction coefficient of the main feed pipe is denoted as .

[0064] Put τ i U cw and U dw Substituting into equation (4) and neglecting higher-order small quantities ΔX, equation (4) can be transformed into: (5) Figure 7 This is a schematic diagram of the slurry circulation pipeline control body in a preferred embodiment of the present invention. The mass conservation equation of the slurry circulation pipeline can be described by equation (6): (6) Among them, U u Let A be the axial velocity of the slurry circulation pipeline at the i-th cyclone reactor location. u Let be the cross-sectional area of ​​the slurry circulation pipeline at the location of the i-th cyclone reactor.

[0065] The axial velocity U in the underflow outlet can be obtained from equation (6). d : (7) Similarly, the momentum conservation equation can be described by equation (8): (8) Where P u Let D be the pressure in the slurry circulation pipeline at the i-th cyclone reactor location. u Let τ be the diameter of the slurry circulation pipeline at the i-th cyclone reactor location. u Given by the Darcy–Weisbach formula, τ u =f u ρ(W u 2 / 8), Uud =β u U u In the formula β u It is the axial velocity component U ud The correction factor. f u The friction coefficient of the slurry circulation pipeline.

[0066] τ u and U ud Substituting into equation (8) and neglecting higher-order small quantities ΔX, equation (8) can be transformed into: (9) From equations (3) and (7) and considering equation (2), the relationship between the axial velocities of the U1-U2 parallel configuration main feed pipe and the slurry circulation pipe can be obtained: (10) The above Figure 6 and Figure 7 The control volume analysis shown aims to explain the theoretical basis for the distribution of flow rate and pressure drop in a parallel swirl reactor group from the perspective of mass conservation and momentum conservation. Figure 6 Used to describe the fluid distribution process within the main feed pipe; Figure 7 This describes the fluid collection process within a slurry circulation pipeline. Therefore, it can be seen that the flow distribution in each branch of a parallel system depends not only on the pipe diameter and the number of branches, but also on the combined effects of frictional resistance along the pipe, local momentum exchange, and the flow direction of the manifold.

[0067] Therefore, the purpose of deriving equations (1) to (10) is to provide a basis for flow uniformity design for various parallel arrangements. By establishing the mass and momentum conservation relationships in the processes of inlet distribution, overflow collection, and underflow convergence, the structural parameters of the main pipe and branches can be optimized according to the pipeline flow direction and boundary conditions, so that each cyclone reactor can obtain similar feed flow rate, exhaust resistance, and slurry discharge resistance, thereby ensuring that stable reaction, stable separation, and stable circulation can still be maintained when multiple reactors are scaled up in parallel.

[0068] like Figure 8 As shown, in some embodiments, this application also provides an integrated photocatalytic hydrogen production method based on parallel swirling reaction and in-situ purification. Utilizing the apparatus of any of the above embodiments, the method includes the following steps: S100: The light emitted by the external light source is focused by the built-in light guide rod and distributed in the internal reaction zone of each swirling reactor.

[0069] When an external light source is activated, light energy is transmitted through a light guide element and efficiently focused and spatially distributed by a built-in light guide rod located inside each swirling reactor, thus constructing a stable and high-intensity excitation light field throughout the entire reaction zone.

[0070] S200: The catalyst slurry is distributed to the tangential feed inlet 21 of each cyclone reactor through the dual-branch feed unit 1, forming a strong cyclone field in the cyclone reactor. The catalyst slurry undergoes photocatalytic hydrogen evolution reaction under the strong cyclone field and light irradiation.

[0071] The uniformly mixed catalyst slurry is pumped in through the main feed pipe 13 and then evenly distributed to the tangential feed inlets 21 of each swirl reactor via the dual-branch feed unit 1. A strong swirling flow field is formed within the reactor, allowing the catalyst particles and reactants to fully contact and undergo photocatalytic hydrogen evolution reaction under the combined influence of the swirling flow field and a high-intensity light field.

[0072] S300: The hydrogen generated by the reaction is enriched in the low-pressure zone at the center of the swirling reactor under the action of the radial pressure gradient of the swirling field, and then discharged through the top overflow port 22 and flowed into the hydrogen collection manifold 41.

[0073] The hydrogen bubbles generated in the reaction migrate, accumulate, and coalesce towards the low-pressure zone at the reactor axis under the radial pressure gradient created by the swirling flow field. They are then continuously and stably discharged from the overflow port at the top of the swirling reactor and enter the hydrogen collection manifold 41. This process enables the immediate, online purification and separation of hydrogen products at the reaction site, accelerating the reaction rate.

[0074] S400: After the reaction and hydrogen separation are completed, the slurry is discharged from the bottom outlet 27 of the cyclone reactor. Part of the slurry is returned to the main feed pipe 13 as circulating slurry to mix with fresh reactants, and the remaining slurry is discharged from the system.

[0075] After the reaction and hydrogen separation are completed, the remaining liquid phase and solid catalyst mixture is discharged from the underflow outlet of the cyclone reactor and divided into two streams according to a predetermined ratio: one stream is returned to the system's main inlet as circulating slurry, where it mixes with fresh reactants to enter the next round of reaction, achieving efficient catalyst reuse; the other stream is discharged from the system to maintain the overall material balance and catalyst concentration within the optimal range. By adjusting this split ratio, the system's operating status can be dynamically optimized.

[0076] In some embodiments, in S100, the residence time of the catalyst slurry in the system is controlled to be 10 min to 120 min by adjusting the ratio of circulating slurry to discharged slurry, so as to achieve a balance between sufficient reaction and equipment compactness.

[0077] In some embodiments, the reaction liquid in the catalyst slurry is wastewater containing oxidizable organic matter, such as organic wastewater containing methanol, ethanol, or glycerol. This achieves wastewater treatment simultaneously with hydrogen production.

[0078] In some embodiments, the processing capacity of the device is adjusted by increasing or decreasing the number of parallel cyclone reactors.

[0079] It should be noted that after the catalyst slurry enters the cyclone reactor through the tangential feed inlet 21, a rotating flow field is formed inside the reactor. An external light source, introduced into the core reaction zone via a built-in light guide, creates illumination conditions within the cyclone reaction space. Under light excitation, the catalyst particles generate photogenerated electrons and holes. The photogenerated electrons participate in the hydrogen evolution reaction to produce hydrogen gas, while the holes are consumed by sacrificial agents or organic pollutants. Simultaneously, the cyclone field enhances the mixing and mass transfer between the liquid-phase reactants and the solid-phase catalyst, and promotes the migration, enrichment, and aggregation of the generated hydrogen microbubbles towards the central low-pressure zone under the action of the radial pressure gradient. The enriched hydrogen gas is continuously discharged through the top overflow outlet 22, achieving immediate and in-situ separation of the hydrogen products; the degassed liquid-solid catalyst slurry is discharged through the bottom underflow outlet 27.

[0080] Based on the above working process, during operation of this device, the slurry containing the reaction liquid, sacrificial agent, and photocatalyst first enters the dual-branch feed unit 1 through the main feed pipe 13 and is evenly distributed to multiple parallel swirl reactors. Photocatalytic hydrogen evolution reaction and in-situ hydrogen separation are simultaneously completed in each reactor. The generated hydrogen is collected in the hydrogen collection manifold 41 through the top overflow ports 22, while the degassed liquid-solid catalyst slurry enters the catalyst slurry circulation pipeline 42 through the bottom underflow port 27 and returns to the main feed pipe 13 according to the flow control section, with some being discharged from the system. Thus, the device achieves continuous operation with uniform feeding, swirl-enhanced reaction, in-situ hydrogen purification, and catalyst slurry recycling.

[0081] Another embodiment is provided. In a clean energy demonstration project in a chemical industrial park, according to the method of the present invention, an integrated photocatalytic hydrogen production device based on parallel cyclone reaction and in-situ purification is used to treat methanol-containing organic wastewater discharged by a chemical plant in the park. Hydrogen energy is produced while the wastewater is pretreated. The specific operation process and effect are described as follows: 1. Wastewater properties and related parameters The properties and parameters of the methanol-containing organic wastewater discharged by the chemical plant before the reaction are shown in Table 1 below.

[0082]

[0083] 2. Integrated Photocatalytic Hydrogen Production Experimental Device The experimental setup employs the integrated parallel swirl structure of this invention. The parallel swirl reaction unit 2 consists of 10 parallel swirl reactors arranged in a U1-U2 configuration. Each swirl reactor has an inner diameter of 85 mm and a height of 450 mm, and is made of high-transmittance quartz glass. The tangential inlet cross-sectional area of ​​the swirl reactor is 150 mm². The dual-branch feed unit 1 uses parallel piping designed based on dual-branch flow theory. By precisely calculating the diameter and length of each branch pipe, the relative deviation of the flow distribution among the 10 reactors is ensured to be less than 3%.

[0084] The light source introduction unit 3 includes an external LED light source (total power 40 kW, spectral range 350-650 nm) and a built-in light guide rod. The end of the light guide rod is equipped with an optical lens to focus the light, extending into the core reaction zone inside each cyclone reactor. The product collection and circulation unit 4 includes a hydrogen collection manifold 41 connecting to each top overflow port 22 and a catalyst slurry circulation pipeline 42 connecting to each bottom underflow port 27. The circulation pipeline is equipped with a regulating valve for flow control. The overall processing capacity of the unit is designed to be 30 m³ / h.

[0085] 3. Implementation process The method of this invention is implemented as follows: When the external LED light source is turned on, the light energy is transmitted through the light guide element and efficiently focused and evenly distributed by the built-in light guide rod set in the center of each swirling reactor, providing a stable and high-intensity light field for the entire reaction area.

[0086] Methanol-containing organic wastewater was mixed with a Pt / COFs photocatalyst to form a catalyst slurry, which was then pumped into the reactor through the main feed pipe 13 and evenly distributed to the tangential feed inlets 21 of 10 parallel swirling reactors via a dual-branch feed unit 1. The feed flow rate of each reactor was controlled at 3.0 m³ / h. The material formed a strong swirling field within the reactors.

[0087] The hydrogen generated by the reaction is enriched in the low-pressure zone at the center of the reactor under the action of the strong radial pressure gradient generated by the swirling flow field, and is continuously and stably discharged from the top overflow port 22 and enters the hydrogen collection manifold 41, realizing the real-time online purification and separation of hydrogen products.

[0088] After the reaction and hydrogen separation are completed, the remaining liquid phase and the slurry formed with the catalyst are discharged from the bottom outlet 27. The slurry is then divided into two streams by a flow control device: approximately 60% of the slurry is returned to the system's main inlet as circulating slurry, mixed with replenished fresh wastewater, and then enters the next round of reaction; approximately 40% is discharged from the system as discharge slurry. The system operates continuously and stably for 72 hours.

[0089] Implementation results: After the system stabilized, the test results are as follows: Uniformity of distribution: The relative deviation of feed flow distribution among the swirl reactors is less than 2.5%, indicating that the parallel pipeline designed based on the dual-branch flow theory has achieved uniform distribution of flow rate and pressure drop.

[0090] Hydrogen production performance: The average hydrogen yield is 135 mmol / h (based on the total yield of 10 reactors), which is about 4.0 times higher than that of a conventional stirred tank reactor (about 34 mmol / h) under the same conditions; the purity of the collected hydrogen is higher than 98.2%.

[0091] Wastewater purification effect: The properties and parameters of the treated wastewater are shown in Table 2 below. The COD removal rate reached 88.6%, and the methanol removal rate reached 96.8%.

[0092]

[0093] Separation and recycling efficiency: The gas-liquid separation efficiency of the cyclone reactor is consistently above 97.5%, and the single-pass catalyst loss rate is less than 0.8%. The efficient recycling of the catalyst is achieved through diversion control.

[0094] Operational stability: After 72 hours of continuous operation, the hydrogen yield fluctuated within ±5%, and the operating conditions of each cyclone reactor were consistent, with no obvious scale-up effect observed.

[0095] The above results show that the device and method of the present invention, under an engineering scale of 30 m³ / h, achieves integrated reaction-separation-recycling through the integrated design of parallel cyclone reaction and in-situ purification, effectively purifying organic wastewater while producing hydrogen efficiently, and has good prospects for engineering application.

[0096] In all examples shown and described herein, any specific values ​​should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.

[0097] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0098] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification, characterized in that, The device includes a dual-branch feed unit, a parallel swirling reaction unit, a light source introduction unit, and a product collection and circulation unit, wherein: The dual-branch flow feeding unit includes a main feed pipe and multiple parallel pipes; The parallel swirl reactor unit includes multiple swirl reactors arranged in parallel. Each swirl reactor has a tangential feed inlet, a top overflow inlet, and a bottom underflow inlet. Each tangential feed inlet is connected to the main feed pipe through a corresponding parallel pipeline. The light source introduction unit includes an external light source and a built-in light guide rod, the built-in light guide rod extending into the internal reaction zone of each of the swirling reactors; The product collection and circulation unit includes a hydrogen collection main pipe and a catalyst slurry circulation pipeline. The hydrogen collection main pipe is connected to the top overflow port of each of the cyclone reactors. One end of the catalyst slurry circulation pipeline is connected to the bottom underflow port of each of the cyclone reactors, and the other end is connected to the main feed pipe.

2. The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification according to claim 1, characterized in that, The dual-branch feed unit also includes a slurry buffer tank and a feed pump. The slurry buffer tank is used to store catalyst slurry. The slurry buffer tank is connected to the main feed pipe through the feed pump. The feed pump is used to pump the catalyst slurry in the slurry buffer tank to the main feed pipe. A flow meter and a regulating valve are provided on the parallel pipeline. The flow meter is used to monitor the flow rate, and the regulating valve is used to regulate the flow rate.

3. The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification according to claim 2, characterized in that, The cyclone reactor includes a cylindrical body, a tangential feed inlet, a top overflow outlet, a bottom underflow outlet, and a double inner cone structure; the tangential feed inlet is located on the upper side wall of the cylindrical body and is used to introduce catalyst slurry and induce cyclone flow. The top overflow port is located at the center of the top along the axial direction of the cylinder, with its lower opening located in the central region of the inner cavity of the cylinder and its upper end connected to the hydrogen collection main pipe.

4. The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification according to claim 3, characterized in that, The top of the cyclone reactor is provided with a first conical structure and the bottom is provided with a second conical structure. The tips of the first conical structure and the tips of the second conical structure are arranged opposite each other to form a double inner cone structure. The double inner cone structure is used to induce the gas phase to converge towards the central axis of the reactor to realize the hydrogen enrichment and separation process.

5. The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification according to claim 1, characterized in that, The end or side of the built-in light guide is provided with an optical lens for focusing light; and / or, the external light source is sunlight or an artificial light source.

6. The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification according to claim 1, characterized in that, The catalyst slurry circulation pipeline is equipped with a flow diversion control device; The diversion control device is a diversion valve with an inlet, a circulation outlet and a discharge outlet. The inlet is connected to the underflow port, the circulation outlet is connected to the main feed pipe, and the discharge outlet is connected to the outside.

7. The integrated photocatalytic hydrogen production device based on parallel swirling reaction and in-situ purification according to claim 1, characterized in that, The connection method between the feed main pipe and the catalyst slurry circulation pipe is selected from at least one of U1 type connection and Z1 type connection: The U1 type connection is defined as follows: the flow direction of the catalyst slurry circulation pipeline is opposite to the flow direction of the feed main pipe; The Z1 type connection is defined as follows: the flow direction of the catalyst slurry circulation pipeline is the same as the flow direction of the feed main pipe; The connection method between the feed main and the hydrogen collection main is selected from at least one of U2 type connection and Z2 type connection: The U2 type connection is defined as follows: the flow direction of the hydrogen collection manifold is opposite to that of the feed manifold; The Z2 type connection is defined as follows: the flow direction of the hydrogen collection manifold is the same as that of the feed manifold; The combination of multiple cyclone reactors is selected from one of the following arrangements: U1-U2 type: The feed main pipe and the catalyst slurry circulation pipe are connected in a U1 type, and the feed main pipe and the hydrogen collection main pipe are connected in a U2 type; U1-Z2 type: The feed main pipe and the catalyst slurry circulation pipe are connected in a U1 type, and the feed main pipe and the hydrogen collection main pipe are connected in a Z2 type; Z1-U2 type: The feed main pipe and the catalyst slurry circulation pipe are connected by a Z1 type, and the feed main pipe and the hydrogen collection main pipe are connected by a U2 type; Z1-Z2 type: The feed main pipe and the catalyst slurry circulation pipe are connected in a Z1 type, and the feed main pipe and the hydrogen collection main pipe are connected in a Z2 type; U1-U2 and Z1-Z2 type: The plurality of cyclone reactors are divided into a first group and a second group, wherein the cyclone reactors in the first group are arranged in a U1-U2 type and the cyclone reactors in the second group are arranged in a Z1-Z2 type. Z1-Z2 and U1-U2 type: The plurality of swirl reactors are divided into a first group and a second group. The swirl reactors in the first group are arranged in a Z1-Z2 type, and the swirl reactors in the second group are arranged in a U1-U2 type.

8. An integrated photocatalytic hydrogen production method based on parallel swirling reaction and in-situ purification, characterized in that, Using the apparatus according to any one of claims 1 to 7, the method comprises the following steps: S100: The light emitted by the external light source is focused by the built-in light guide and distributed in the internal reaction zone of each swirl reactor; S200: The catalyst slurry is distributed to the tangential feed inlet of each cyclone reactor through the dual-branch feed unit, forming a strong cyclone field in the cyclone reactor. The catalyst slurry undergoes photocatalytic hydrogen evolution reaction under the strong cyclone field and light irradiation. S300: The hydrogen generated by the reaction is enriched towards the center of the swirling reactor under the action of the radial pressure gradient of the swirling field, and then discharged through the top overflow port and merged into the hydrogen collection manifold. S400: After the reaction and hydrogen separation are completed, the slurry is discharged from the bottom outlet of the cyclone reactor. Part of the slurry is returned to the main feed pipe as circulating slurry to mix with fresh reactants, and the remaining slurry is discharged as discharge slurry and discharged from the integrated photocatalytic hydrogen production unit.

9. The integrated photocatalytic hydrogen production method based on parallel swirling reaction and in-situ purification according to claim 8, characterized in that, In S100, the circulation residence time of the catalyst slurry in the system is controlled to be 10 min to 120 min by adjusting the ratio of the circulating slurry to the discharged slurry.

10. The integrated photocatalytic hydrogen production method based on parallel swirling reaction and in-situ purification according to claim 8, characterized in that, The reaction liquid in the catalyst slurry is industrial wastewater containing methanol, ethanol or glycerol; And / or, by increasing or decreasing the number of the cyclone reactors connected in parallel, the processing capacity of the device can be adjusted.

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