A dual-mode photocatalytic reactor based on a biomimetic *Hylocereus* structure

Abstract

A dual-mode photocatalytic reactor based on the biomimetic structure of *Hylocereus undatus* is disclosed, relating to the field of industrial waste gas purification technology. The reaction unit mimics the spherical multicellular aggregate structure of *Hylocereus undatus*, which efficiently utilizes light energy and promotes material exchange. This constructs a novel device that can simultaneously enhance light energy capture, optimize the reaction flow field, and achieve modular maintenance, thereby improving energy utilization efficiency, mass transfer performance, and ease of operation.

Description

Technical Field

[0001] This invention relates to the field of industrial waste gas purification technology, specifically to a dual-mode photocatalytic reactor based on a biomimetic *Hylocereus undatus* structure. Background Technology

[0002] Industrial waste gas mainly originates from various industrial production processes. Its composition is complex, containing various volatile organic compounds, polycyclic aromatic hydrocarbons, and other harmful substances, posing a clear pollution risk to the ecological environment and human health. While traditional treatment technologies such as physical adsorption and thermal combustion each have their own characteristics, they also suffer from problems such as adsorbent regeneration, high energy consumption, or secondary pollution. Photocatalytic oxidation technology, due to its ability to drive reactions using light energy at ambient temperature and pressure, is considered a promising purification solution, and related research continues to deepen.

[0003] When photocatalysis technology is applied in practical engineering, reactor design becomes crucial to its efficiency. (See attached image) Figure 1 and attached Figure 2 As shown, most existing photocatalytic reactors rely excessively on continuously operating artificial ultraviolet light sources for energy supply, failing to fully integrate and utilize sunlight. This leads to increased operating costs and weakens the economic appeal of the technology to some extent. From a reaction engineering perspective, the internal flow field organization of common reactor configurations is often suboptimal, easily resulting in uneven airflow distribution, short-circuiting, or local dead zones, limiting gas-solid phase mass transfer efficiency. Catalyst loading is mostly in the form of fixed beds or surface coatings. While this method facilitates installation, it limits the effective specific surface area of ​​the catalyst, fails to fully expose active sites, and is inconvenient for replacement or regeneration after catalyst deactivation, hindering long-term stable operation and maintenance of the device. Furthermore, traditional structures typically lack sufficient modular expansion capabilities to handle different processing scales. Summary of the Invention

[0004] To overcome the shortcomings of the above technologies, this invention provides a photocatalytic reactor that simultaneously enhances light energy capture, optimizes the reaction flow field, and achieves modular maintenance by mimicking the spherical multicellular aggregate structure of *Euphorbia hirta* to efficiently utilize light energy and promote material exchange.

[0005] The technical solution adopted by this invention to overcome its technical problems is:

[0006] A dual-mode photocatalytic reactor based on a biomimetic *Hylocereus undatus* structure, comprising:

[0007] The outer shell has a hemispherical structure, with the spherical surface and the bottom surface of the outer shell sealed together, forming a closed cavity in the middle. The outer shell is made of transparent material, with an air outlet at the top and several air inlets on the bottom surface.

[0008] The protective cover has a hemispherical structure and is set in the cavity of the outer shell. The spherical surface of the protective cover is sealed to the bottom surface, forming a closed cavity in the middle. The protective cover and the outer shell are set concentrically, and a hemispherical cavity is formed between the inner wall of the outer shell and the outer wall of the protective cover. The air inlet and air outlet are connected to the cavity.

[0009] Several ultraviolet lamps are installed in the cavity of the protective cover;

[0010] Several reaction units are evenly spaced in the cavity between the protective cover and the outer shell by a fixing mechanism. The reaction unit is a spherical structure, which is sealed on all sides and has a cavity inside. The cavity of the reaction unit is filled with a photocatalyst. Each reaction unit has an exhaust microhole at the top and an intake microhole at the bottom. Both the exhaust microhole and the intake microhole are connected to the cavity inside the reaction unit.

[0011] Preferably, the outer casing is made of 11mm thick tempered glass.

[0012] Preferably, the protective cover is made of 3mm thick quartz glass.

[0013] Preferably, the bottom surface of the outer shell is provided with 12 air inlets, and each air inlet is evenly spaced along the circumference with the center of the outer shell as the center.

[0014] Preferably, the axes of the air inlet and exhaust outlet are both arranged in the vertical direction.

[0015] Preferably, the cavity of the protective cover is equipped with 43 30W ultraviolet lamps and 42 40W ultraviolet lamps, and the ultraviolet lamps are evenly spaced along the hemispherical surface.

[0016] Preferably, the reaction units are made of quartz glass, and the number of reaction units is 42.

[0017] Preferably, the photocatalyst is a Mn-Ce bimetallic MOF catalyst.

[0018] Furthermore, the aforementioned fixing mechanism is a hemispherical support, with several circular holes evenly arranged on the spherical surface of the support. The reaction unit is sealed and inserted into the corresponding circular hole by a fluororubber O-ring. The exhaust micro-hole and the intake micro-hole of the reaction unit are coaxial and their axes pass through the center of the outer shell.

[0019] To reduce exhaust resistance, the above-mentioned reaction unit includes reaction unit I and reaction unit II. The outer diameter of reaction unit I is larger than the outer diameter of reaction unit II. The four reaction units II are arranged in a cross shape at the top of the support.

[0020] The beneficial effects of this invention are:

[0021] (1) By incorporating the surface cell layer structure of biomimetic algae, a three-dimensional radial diffusion flow field and modular distributed reaction unit were innovatively designed, which maximized the contact area between the waste gas and the catalyst, enhanced the mass transfer power, and effectively avoided the problem of uneven airflow distribution in traditional reactors.

[0022] (2) A dual-mode intelligent operation strategy combining "sunlight-driven atmospheric pressure adsorption-catalysis" and "ultraviolet light-excited enhanced purification" was proposed. This strategy makes full use of natural energy, only activating high-energy-consuming ultraviolet light sources when necessary, achieving the optimal balance between purification efficiency and operational economy, with significant energy-saving and consumption-reducing effects.

[0023] (3) The photocatalyst is packaged in a modular pre-assembled unit. This design not only protects the catalyst and facilitates independent evaluation and replacement of its performance, but also achieves "plug and play" maintenance, greatly improving the maintainability and operational flexibility of the system. In addition, the spherical shell is conducive to the transmission of internal and external light sources and the uniform distribution of the internal light field.

[0024] (4) The overall structure is compact, and the biomimetic design makes the logic of each functional layer clear and the collaboration efficient. The hemispherical structure provides the maximum effective reaction volume in a limited space, and the modular design also makes it easy to add or remove units according to the actual gas volume processed, with strong scalability. Attached Figure Description

[0025] Figure 1 A top view of a traditional photocatalytic reactor;

[0026] Figure 2 This is a side view of a traditional photocatalytic reactor.

[0027] Figure 3 This is a front view structural diagram of the present invention;

[0028] Figure 4 This is a side view of the present invention;

[0029] Figure 5 This is a top view of the structure of the present invention;

[0030] Figure 6 This is a bottom view of the structure of the present invention;

[0031] Figure 7 This is a front cross-sectional view of the present invention;

[0032] Figure 8 These are three views of the bracket of the present invention, wherein (a) is a top view of the bracket, (b) is a side view of the bracket, and (c) is a front view of the bracket;

[0033] Figure 9These are three views of the reaction unit of the present invention, wherein (a) is a top view of the reaction unit, (b) is a side view of the reaction unit, and (c) is a front view of the reaction unit;

[0034] Figure 10 These are three views of the ultraviolet lamp matrix of the present invention, wherein (a) is a top view of the ultraviolet lamp matrix, (b) is a side view of the ultraviolet lamp matrix, and (c) is a front view of the ultraviolet lamp matrix.

[0035] In the diagram, 1. Outer shell 2. Air inlet 3. Air outlet 41. Reaction unit I 42. Reaction unit II 5. Support 6. Protective cover 7. Ultraviolet lamp 8. Air inlet micro-hole 9. Exhaust micro-hole Detailed Implementation

[0036] The following is in conjunction with the appendix Figure 1 To be continued Figure 10 The present invention will be further described below.

[0037] Through long-term evolution, organisms in nature have developed many highly efficient systems for material transfer and energy utilization. For example, *Hylocordia hygrophora*, a typical photosynthetic organism, consists of hollow spherical aggregates composed of numerous orderly arranged cells. This structure not only facilitates efficient exchange of gases and nutrients in fluid environments but also adapts itself for the effective capture and utilization of light energy. This biological prototype provides valuable biomimetic inspiration for the design of photocatalytic reactors: by simulating its hollow, porous, and light-light-optimized geometry, it is hoped that new reactor configurations can be constructed that simultaneously enhance light energy distribution, optimize the reaction flow field, and promote mass transfer processes. Therefore, exploring and developing a novel photocatalytic reactor that deeply integrates such biomimetic concepts and can intelligently match different pollution loads and lighting conditions is of positive significance for promoting the practical application and efficiency of industrial waste gas treatment technologies. (See attached...) Figure 3As shown, this invention innovatively designs a dual-mode photocatalytic reactor based on a biomimetic *Hylocereus undatus* structure to address the problems of single energy supply, low internal mass transfer efficiency, and difficult catalyst maintenance in existing photocatalytic purification technologies. The reactor includes: a shell 1, which is hemispherical in shape, with its spherical surface and bottom surface sealed together to form a closed cavity; the shell 1 is made of transparent material; an outlet 3 is provided at the top of the shell 1; and several inlets 2 are provided on the bottom surface of the shell 1; and a protective cover 6, also hemispherical in shape, is disposed within the cavity of the shell 1. The spherical surface and bottom surface of the protective cover 6 are sealed together to form a closed cavity. The protective cover 6 is concentrically positioned with the shell 1, and a hemispherical cavity is formed between the inner wall of the shell 1 and the outer wall of the protective cover 6. Both the inlets 2 and outlets 3 are... The container is connected to the cavity; within the cavity, the support 5 and several reaction units are evenly separated; wherein, the air inlet 2 is located inside the support 5, and the air outlet 3 is located outside the support 5; several ultraviolet lamps 7 are installed in the cavity of the protective cover 6; several reaction units are evenly spaced in the cavity between the protective cover 6 and the outer shell 1 by a fixing mechanism. The reaction unit is a spherical structure, sealed on all sides, and has an internal cavity. The cavity of the reaction unit is filled with a photocatalyst. Each reaction unit has an exhaust microhole 9 at its top and an air inlet microhole 8 at its bottom. Both the exhaust microhole 9 and the air inlet microhole 8 are connected to the internal cavity of the reaction unit. The air inlet microhole 8 is located inside the support 5, and the exhaust microhole 9 is located outside the support 5.

[0038] The industrial waste gas to be treated undergoes dust removal and cooling pretreatment to meet the operating conditions at the reactor inlet (temperature ≤ 60℃, particulate matter concentration ≤ 30mg / Nm³). 3 The pretreated exhaust gas is delivered through an inlet pipe to several inlet holes 2 at the bottom of the reactor. The exhaust gas is injected tangentially or radially into the hemispherical cavity inside the outer shell 1 and protective cover 6. Under the constraint and guidance of the hemispherical cavity walls, the airflow naturally forms a three-dimensional radial flow field that diffuses uniformly from the central region to the spherical outer shell. Driven by this three-dimensional radial flow field, the exhaust gas moves from the center to the periphery. Its flow path is designed to sequentially pass through the inlet micropores 8 at the bottom of all reaction units. The exhaust gas passes through the inlet micropores 8 and enters the interior of each reaction unit, making full contact with the photocatalyst loaded within.

[0039] Furthermore, based on the real-time monitoring of exhaust gas concentration signals by the PID controller, the intelligent control system automatically selects and executes one of the following two photocatalytic modes:

[0040] (1) Low-energy adsorption-photocatalysis mode: When the exhaust gas concentration is continuously lower than the set threshold, the control system keeps all the ultraviolet lamps 7 inside the protective cover 6 in the off or minimum power standby state. The driving force of the reaction mainly depends on the sunlight (mainly visible light) passing through the outer shell 1. In this mode, the system purifies by the synergistic effect of adsorption enrichment and visible light photocatalysis, with extremely low energy consumption.

[0041] (2) Enhanced photocatalytic purification mode: When the exhaust gas concentration exceeds the set threshold, or when the system judges that the catalyst adsorption is approaching saturation, the control system immediately starts or increases the power of each built-in ultraviolet lamp 7. High-intensity UVC (main wavelength 254nm) and UVA (main wavelength 365nm) ultraviolet light radiates outward from the irradiation core layer, penetrates the reaction unit shell, and deeply excites the catalyst to generate a large number of highly active free radicals (such as ·OH), which rapidly and thoroughly oxidize and decompose pollutants. The gas purified inside each reaction unit is discharged through the exhaust micro-holes 9 at the top of each reaction unit. The purified gas from all reaction units gathers in the hemispherical cavity between the outer shell 1 and the protective cover 6, and flows upward along the hemispherical cavity. Finally, the collected clean gas is discharged from the system through the single total exhaust hole 3 located at the apex of the hemispherical outer shell. When the exhaust gas moves from the center to the periphery, it must pass through the intake micro-holes 8 opened at the bottom of each reaction unit in sequence, so as to fully contact all photocatalysts, effectively avoiding flow short circuits or dead zones, and significantly improving mass transfer efficiency.

[0042] By mimicking the spherical multicellular aggregate structure of *Hylocereus undatus* to efficiently utilize light energy and promote mass exchange, the reaction unit has constructed a novel device that can simultaneously enhance light energy capture, optimize the reaction flow field, and achieve modular maintenance, aiming to improve energy utilization efficiency, mass transfer performance, and ease of operation.

[0043] In one embodiment of the invention, the outer shell 1 is made of 11mm thick tempered glass. This material ensures structural strength while maintaining a transmittance of over 97% in the visible light band, enabling efficient introduction of natural light sources. Its biomimetic shape and high light transmittance combine to achieve the integration of physical protection and primary light energy supply. The protective cover 6 is made of 3mm thick quartz glass, safely isolating the irradiation core from the reaction environment and forming a smooth inner wall flow field boundary. (See attached...) Figure 4 and attached Figure 7 As shown, preferably, the diameter A of the outer shell 1 is 280 mm and the height B is 150 mm. This biomimetic shape, combined with high light transmittance, achieves an integrated function of physical protection and primary light energy supply. An air vent 3 is located at the center of the top of the outer shell 1, with a diameter C of 15 mm and a length E of 15 mm. This centralized exhaust design helps maintain a stable flow field within the hemispherical cavity and controls the flow velocity at the air vent 3 to approximately 7.5 m / s at the maximum design airflow, thereby balancing the system back pressure and gas collection efficiency.

[0044] As attached Figure 6 As shown, in one embodiment of the present invention, the bottom surface of the outer shell 1 is provided with 12 air inlets 2, each air inlet 2 being evenly spaced along the circumference with the center of the outer shell 1 as the center. After the waste gas to be treated is injected through these inlets, it is injected into the reactor interior in a tangential or radial manner, naturally forming a three-dimensional radial flow field that diffuses uniformly from the center to the spherical surface under the constraint of the hemispherical cavity wall. In this embodiment, the axes of both the air inlets 2 and the air outlets 3 are arranged vertically. The diameter D of each air inlet 2 is 22 mm, the length F is 15 mm, and the distance P between its center and the outer shell 1 is 38 mm. Only one air outlet 3 is provided, achieving centralized exhaust, which helps maintain the stability of the flow field within the cavity between the protective cover 6 and the outer shell 1, thus balancing the system back pressure and gas collection efficiency.

[0045] As attached Figure 10 As shown, in one embodiment of the present invention, the cavity of the protective cover 6 is equipped with 43 30W ultraviolet lamps 7 (main peak wavelength 254nm) and 42 40W ultraviolet lamps 7 (main peak wavelength 365nm), with each ultraviolet lamp 7 evenly spaced along the hemispherical surface. The total number of ultraviolet lamps 7 is 85, forming a uniform radiation field on the hemispherical surface. Through optical software simulation optimization, the diameter N of the ultraviolet lamps 7 is 15mm, the diameter O of the hemispherical ultraviolet lamp matrix composed of all 85 ultraviolet lamps 7 is 115mm, the diameter L of the protective cover 6 is 170mm, and the height M of the protective cover 6 is 85mm. The ultraviolet lamp matrix serves as the core of the system's enhanced energy supply, analogous to the "photosynthetic center" where algae gather and utilize light energy. This configuration can form a relatively uniform ultraviolet radiation field within the hemispherical space to efficiently excite the photocatalyst.

[0046] In one embodiment of the present invention, the reaction unit is made of quartz glass by an integrated welding process. The adhesive-free integrated welding process fundamentally eliminates the risk of leakage and ensures long-term sealing. The number of reaction units is 42, and the quartz glass has good light transmittance.

[0047] As attached Figure 8 As shown, in one embodiment of the present invention, the photocatalyst is a Mn-Ce bimetallic MOF catalyst with a specific surface area between 1650 and 2030 m² / g and a saturated adsorption capacity of about 0.30 g / g for polycyclic aromatic hydrocarbons, exhibiting high adsorption capacity and photocatalytic degradation activity.

[0048] In one embodiment of the present invention, the fixing mechanism is a hemispherical bracket 5. A plurality of circular holes are evenly arranged on the spherical surface of the bracket 5. The reaction unit is sealed and inserted into the corresponding circular holes using fluororubber O-rings. The exhaust micro-hole 9 and the intake micro-hole 8 of the reaction unit are coaxial, and their axes pass through the center of the outer shell 1. The diameter G of the bracket 5 is 240 mm, and the height H is 120 mm. The airtight connection and convenient maintenance are achieved by sealing the reaction unit into the corresponding circular holes using fluororubber O-rings.

[0049] As attached Figure 5 and attached Figure 9 As shown, the reaction unit includes reaction unit I 41 and reaction unit II 42. The outer diameter of reaction unit I 41 is larger than that of reaction unit II 42. The four reaction units II 42 are arranged in a cross shape at the top of the support 5. The shell diameter I of reaction unit II 42 is 36 mm and the wall thickness is 2 mm; the shell diameter I of the remaining 38 reaction units I 41 is 42 mm and the wall thickness is 2 mm. The center distance between two adjacent reaction units varies depending on the unit type, and is defined as follows: between two adjacent reaction units II 42, the center distance Q is 39 mm; between two adjacent reaction units I 41, the center distance R is 45 mm; and between two adjacent reaction units I 41 and reaction unit II 42, the center distance S is 41 mm. The quartz glass used has a transmittance of no less than 97% for ultraviolet light at wavelengths of 254 nm and 365 nm to ensure the effective utilization of the built-in light source. At the top and bottom poles of each reaction unit housing, short quartz glass tubes with an inner diameter J of 2.5 mm (top) and an inner diameter K of 4.1 mm (bottom) are fused together to form an exhaust micro-hole 9 and an intake micro-hole 8.

[0050] The dual-mode photocatalytic reactor of this invention, based on a biomimetic *Hylocereus undatus* structure, can be configured with an intelligent control system designed to achieve dual-mode intelligent operation based on both concentration and time parameters. A metering device with a range of 0-200 mg / m³ is installed on the main inlet pipe. 3 A photoionization detector (PID) is used for real-time monitoring. The control logic is as follows: when the concentration value detected by the PID remains above a set threshold (20 mg / m³) for 30 seconds... 3 When the concentration value remains below the threshold for 180 seconds, the system automatically activates all UV lamps and switches to "enhanced photocatalytic purification mode." If the concentration value remains below this threshold for 180 seconds, the UV lamps automatically shut off, switching back to "low-energy adsorption-photocatalysis mode." Furthermore, the system has a built-in protective timed regeneration program: if UV lamp 7 is continuously shut off for more than a preset time (e.g., 48 hours), regardless of the real-time concentration, the system will automatically activate the UV lamp matrix and run it at a lower power for a predetermined period (e.g., 90 minutes) to perform in-situ photocatalytic regeneration of the catalyst, restoring its adsorption and catalytic activity.

[0051] This invention also relates to a method for enhancing the photocatalytic degradation of asphalt fume, comprising the following steps:

[0052] S1: Uniform introduction of flue gas and formation of biomimetic radial flow field.

[0053] The asphalt fumes, after pre-dust removal and cooling (temperature ≤60℃, particulate matter concentration ≤30mg / Nm³), will be treated. 3 Driven by an induced draft fan, the flue gas is introduced into the main inlet pipe and evenly distributed to 12 radial inlet holes 2. The flue gas is controlled to enter the area between the outer shell 1 and the protective cover 6 at a flow rate of 4~6 m / s. Under the constraint and guidance of the hemispherical geometry, the incident airflow rapidly evolves into a three-dimensional radial flow field that diffuses uniformly and stably from the central region to the entire spherical surface. This flow field highly simulates the mass diffusion and exchange process promoted by the hollow spherical structure of *Hylocereus undatus*, avoiding the "flow short-circuiting" or "mass transfer dead zone" phenomena commonly found in traditional axial flow reactors.

[0054] S2: Distributed forced trapping and intra-cell adsorption enrichment.

[0055] As the radial airflow carrying pollutants such as polycyclic aromatic hydrocarbons diffuses towards the outer spherical surface, its flow path is designed to pass through the bottom of each modular pre-assembled reaction unit. Under the local pressure difference generated by the inlet micropores 8 at the bottom of the reaction unit, part of the airflow is selectively "captured" and drawn into the interior of the reaction unit. The particulate Mn-Ce bimetallic organic framework (MOF) catalyst filling the reaction unit constitutes a deep, high specific surface area porous fixed bed. When the flue gas passes through the porous bed, the pollutants are transferred through molecular diffusion and convection, making full contact with the catalyst's large inner surface and abundant active sites, and are rapidly adsorbed and enriched in the catalyst pores, completing the initial concentration and capture of pollutants.

[0056] S3: Adaptive dual-mode photocatalytic oxidation degradation.

[0057] Pollutants enriched on the active sites of the catalyst undergo photocatalytic oxidation. The process is automatically controlled by an intelligent control system that selects the operating mode based on the inlet pollutant concentration.

[0058] In the low-energy adsorption-photocatalysis mode, the control system keeps all built-in ultraviolet lamps 7 off. Sunlight (mainly visible light and some near-ultraviolet light) passes through the outer shell 1 and the shell of the reaction unit, exciting the Mn-Ce bimetallic MOF catalyst to generate photogenerated carriers. Photogenerated holes and derived free radicals (such as ·O2⁻) that migrate to the catalyst surface gradually oxidize and degrade adsorbed polycyclic aromatic hydrocarbons and other organic compounds into harmless or low-harm substances such as CO2 and H2O. In this mode, the system has extremely low energy consumption and is suitable for continuous compliance with flue gas standards or low-concentration operating conditions.

[0059] When the pollutant concentration monitored by the photoionization detector (PID) at the entrance exceeds the set threshold (e.g., 20 mg / m³) for 30 consecutive seconds... 3 When the system automatically switches to enhanced photocatalytic purification mode, each ultraviolet lamp 7 is activated. High-intensity UVC (254nm) and UVA (365nm) photons penetrate the shell of the reaction unit, significantly increasing the generation rate and separation efficiency of electron-hole pairs within the catalyst, thereby generating extremely high concentrations of highly oxidizing species such as hydroxyl radicals (·OH). Under these conditions, the reaction kinetics are significantly accelerated. Not only are pollutants adsorbed on the catalyst surface rapidly and deeply purified, but some gaseous free radicals can also diffuse into the gas phase space within the shell, performing gas-solid synergistic oxidation on pollutant molecules that have not yet been adsorbed. This achieves efficient and rapid purification of high-concentration or impact-load flue gas.

[0060] S4: Purified gas collection and emission in compliance with standards.

[0061] The gases that have undergone oxidation and purification within each reaction unit are discharged through the top exhaust micro-holes 9. These dispersed clean gas flows rise and mix thoroughly within the annular gas collection chamber between the outer shell 1 and the protective cover 6, before finally being discharged from the system through the central exhaust port 3 at the top. The outlet gas can be connected to the plant's main exhaust pipeline, and after testing, it meets the relevant environmental protection requirements such as the "Integrated Emission Standard for Air Pollutants" to achieve compliant emissions.

[0062] To ensure that the hemispherical shell photocatalytic reactor achieves its designed goal of "high efficiency and low energy consumption," a quantitative evaluation of its core optical performance and energy harvesting efficiency is necessary. The following analysis, through calculation of the effective illumination area and analysis of the intracavity light field distribution, elucidates the significant advantages of this biomimetic structure over traditional flat plate configurations in solar energy utilization.

[0063] The optical capture capability of a reactor is the physical basis for its energy utilization efficiency. By calculating the ratio of the effective illuminated area of ​​the reactor of this invention to that of a flat plate reactor with the same projected floor area (i.e., the same bottom circular area), its optical gain coefficient can be defined and quantified. This coefficient integrates the reflection and transmission of light from the inner wall of the hemispherical shell 1, as well as the secondary capture and utilization efficiency of light energy by the distributed modular reaction units within the cavity.

[0064] ;

[0065] In the formula, Let be the radius of the base of the hemispherical shell. For the light capture correction factor of the hemispherical wall of the outer shell, , For the number of pre-loaded balls, , The effective light utilization coefficient is the factor that the small spheres cannot fit into. .

[0066] Calculation results show that the equivalent effective illumination area of ​​the structure of this invention is 3.58 times that of the traditional flat-plate structure. This geometric gain directly increases the solar photon flux received by the system per unit time to a new order of magnitude, forming the core physical basis for the system to achieve a 35% reduction in power consumption. Simultaneously, this configuration, in conjunction with the central ultraviolet light source, ensures a highly uniform light field distribution within the cavity, providing crucial support for the efficient and stable catalytic reaction.

[0067] The biomimetic radial flow field formed inside the reactor is stable, and the air intake of each module unit is uniform, with no flow field segregation or unit "idleness" phenomenon. In continuous operation tests on typical asphalt fumes (concentration range of 10-150 mg / m³ based on total volatile organic compounds), the present invention can achieve a single-pass removal rate of 97.7% for pollutants in the "enhanced photocatalytic purification mode" and can still maintain an overall purification efficiency of over 85% in the "low-energy adsorption-photocatalytic mode", while saving 35% of electricity and significantly reducing system energy consumption.

[0068] Comparative Example: Degradation of Asphalt Fume by a Traditional Flat-Plate Photocatalytic Reactor

[0069] The comparison device used in this comparative example is as shown in the attached figure. Figure 1 and attached Figure 2 The conventional flat-plate photocatalytic reactor system is shown. This comparative example aims to highlight the innovative advantages of the present invention in reactor geometry, flow field design, and light energy utilization efficiency by comparing it with the device described in the embodiments of the present invention under the same projected floor area, the same processing load, the same catalyst, and the same control logic. The core difference between this comparative example system and the system of the present invention is that the reactor body adopts a conventional flat-plate box structure, rather than the hemispherical biomimetic radial flow field and modular pre-assembled unit structure of the present invention.

[0070] The conventional photocatalytic degradation device configuration is based on a conventional photocatalytic reactor design, with the comparative device being a vertical box structure. The bottom of the box is circular, and its diameter is strictly consistent with the bottom diameter of the hemispherical reactor of this invention to ensure that the two occupy the same area. The side walls and top cover of the box are made of 11mm thick tempered glass with a visible light transmittance greater than 97%. A flat-plate catalytic module is installed inside the box, filled with Mn-Ce bimetallic MOFs catalyst to form a uniformly thick two-dimensional catalytic bed. The catalyst performance parameters and its total filling mass are strictly equal to those of the embodiment of this invention. A set of ultraviolet lamp spheres (composed of a total of 85 UVC and UVA lamp beads in the same wavelength ratio) are evenly arranged in the center of the box and encapsulated in a quartz glass protective sphere. The inlet and outlet pipes are located on opposite sides of the top cover. A photoionization detector (PID) of the same model is installed at the inlet, and the intelligent control system logic settings are exactly the same as those of the embodiment of this invention.

[0071] Specific traditional usage is shown in the attached document. Figure 1 and attached Figure 2 The operation steps of the traditional flat-plate photocatalytic reactor system for degrading asphalt fume are as follows:

[0072] S1: System check and flue gas introduction.

[0073] The asphalt fumes that have undergone the same pre-dust removal and cooling treatment (temperature ≤60℃, particulate matter concentration ≤30mg / Nm³) 3 The airflow is introduced into the intake pipe under the drive of the induced draft fan. The airflow is evenly distributed across the cross-section of the box and flows at a velocity of 4-6 m / s.

[0074] S2: Plug flow contact and surface catalysis.

[0075] The gas flow proceeds vertically through the gaps in the flat-plate catalyst bed in an approximately plug flow manner. Pollutant molecules diffuse and adsorb onto the catalyst bed surface primarily due to their concentration gradient. In this mode, gas-solid contact is dominated by two-dimensional planar diffusion, resulting in a relatively large mass transfer path and resistance.

[0076] S3: Fixed-mode photocatalytic oxidation.

[0077] The photocatalytic process is controlled by the same intelligent control system based on the inlet PID reading. When the concentration is below 20 mg / m³, the catalyst is excited solely by natural sunlight (through the glass enclosure), which is the conventional mode. When the concentration exceeds the limit and remains so for 30 seconds, the ultraviolet lamp array is activated to provide enhanced illumination.

[0078] S4: Product collection and discharge.

[0079] The purified gas is discharged through the outlet pipe. The outlet gas must be connected to a monitoring system to ensure that it complies with the "Integrated Emission Standard for Air Pollutants".

[0080] Parallel comparison tests and results analysis:

[0081] The conventional flat-plate reactor of this comparative example and the hemispherical reactor of the present invention were placed on the same experimental platform and purged with asphalt fumes of the same source and concentration. Long-term performance comparison tests were conducted under the same environmental conditions.

[0082] (1) Comparison of core geometry and optical efficiency:

[0083] Effective illumination area measurement: Through 3D modeling calculation and actual measurement, under the condition of strictly ensuring the same floor space, the total effective illumination area of ​​the 42 modular reaction units in the hemispherical structure of this invention is 3.58 times that of the two-dimensional catalytic plate in a traditional flat plate reactor. This geometric gain is the core physical innovation of this invention.

[0084] Photon flux analysis: The above gain means that, under the same natural sunlight or the same power artificial light source irradiation, the effective photon flux captured and utilized by the reactor system of this invention per unit time is theoretically 3.58 times that of the traditional flat plate structure, laying the foundation for a leap in energy efficiency from a physical perspective.

[0085] (2) Comparison of overall performance and energy consumption:

[0086] During a continuous comparison run lasting 720 hours, the following key data were obtained:

[0087] Purification efficiency: when the average concentration is 80 mg / m³ 3 Under impact loads, the single-pass removal rate of this invention remained stable at 97.7% in the "enhanced photocatalytic purification mode". In contrast, the traditional flat-plate reactor, under the same inlet conditions and with all UV lamps turned on in the "enhanced mode", only achieved a maximum single-pass removal rate of 85.0%. The efficiency difference mainly stems from the uneven distribution of mass transfer paths and light energy.

[0088] System energy consumption: To achieve a similar high removal rate (>97%) as this invention, the comparative reactor must significantly reduce the processing air volume to compensate for its insufficient mass transfer and light utilization, resulting in a surge in energy consumption per unit of waste gas treated. Comprehensive calculations show that, while achieving the same purification effect, the overall system power consumption of this invention is reduced by 35% compared to the traditional flat-plate reactor in the comparative reactor.

[0089] Flow field stability observation: In the later stages of operation of the comparative reactor, it was observed that the airflow easily formed vortices or "short-circuit" channels in the corners of the tank and between the plates, resulting in a decrease in the utilization rate of some catalytic areas. However, the biomimetic radial flow field in the embodiment of this invention showed stability and no similar phenomena.

[0090] This comparative example, through rigorous parallel experiments, demonstrates that, under the condition of controlling all variables consistently and only changing the main geometry of the reactor, the traditional flat-plate reactor design, due to its inherent two-dimensional planar limitations and plug flow mass transfer mode, faces insurmountable bottlenecks in light capture efficiency and gas-solid contact efficiency. The hemispherical biomimetic radial flow field structure proposed in this invention, by creating a fundamental geometric gain of 3.58 times the effective illumination area, combined with forced penetration three-dimensional mass transfer, successfully overcomes the aforementioned bottlenecks. This is not only key to increasing the single-pass pollutant removal rate from 85.0% to 97.7%, but also the core physical basis for achieving the significant economic benefit of a 35% reduction in overall system energy consumption.

[0091] Through the above embodiments, this invention integrates biomimetic structure, modular design, high-performance catalyst, and intelligent control strategy to construct a highly efficient, energy-saving, and easy-to-maintain industrial waste gas purification system. This system can automatically select the optimal operating mode based on actual working conditions, ensuring purification effectiveness while minimizing operating energy consumption and maintenance costs, thus possessing significant industrial application value.

[0092] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-mode photocatalytic reactor based on the structure of the biomimetic coccolithophore, characterized in that, include: The outer shell (1) has a hemispherical structure. The spherical surface of the outer shell (1) is sealed to the bottom surface, forming a closed cavity in the middle. The outer shell (1) is made of transparent material. An air outlet (3) is provided at the top of the outer shell (1), and several air inlets (2) are provided on the bottom surface of the outer shell (1). The protective cover (6) has a hemispherical structure and is set in the cavity of the outer shell (1). The spherical surface of the protective cover (6) is sealed to the bottom surface, forming a closed cavity in the middle. The protective cover (6) and the outer shell (1) are set concentrically. The inner wall of the outer shell (1) and the outer wall of the protective cover (6) form a hemispherical cavity. The air inlet (2) and the air outlet (3) are both connected to the cavity. Several ultraviolet lamps (7) are installed in the cavity of the protective cover (6); Several reaction units are evenly spaced in the cavity between the protective cover (6) and the outer shell (1) by a fixing mechanism. The reaction unit is a spherical structure, which is sealed on all sides and has a cavity inside. The cavity of the reaction unit is filled with a photocatalyst. Each reaction unit has an exhaust microhole (9) at the top and an air inlet microhole (8) at the bottom. Both the exhaust microhole (9) and the air inlet microhole (8) are connected to the cavity inside the reaction unit. In the cavity, the support (5) and several reaction units are evenly separated. The air inlet (2) is located inside the support (5), and the air outlet (3) is located outside the support (5). The bottom surface of the outer shell (1) is provided with 12 air inlets (2), and each air inlet (2) is evenly spaced along the circumference with the center of the outer shell (1) as the center. The fixing mechanism is a hemispherical bracket (5). Several round holes are evenly arranged on the spherical surface of the bracket (5). The reaction unit is sealed and inserted into the corresponding round hole by a fluororubber O-ring. The exhaust micro-hole (9) of the reaction unit is coaxial with the air inlet micro-hole (8) and the axis passes through the center of the shell (1). The air inlet micro-hole (8) is located inside the bracket (5), and the exhaust micro-hole (9) is located outside the bracket (5).

2. The dual-mode photocatalytic reactor based on the biomimetic hollow-globulus structure according to claim 1, characterized in that: The outer shell (1) is made of 11mm thick tempered glass.

3. The dual-mode photocatalytic reactor based on the biomimetic hollow-globulus structure according to claim 1, characterized in that: The protective cover (6) is made of 3mm thick quartz glass.

4. The dual-mode photocatalytic reactor based on the biomimetic *Hylocereus undatus* structure according to claim 1, characterized in that: The axes of the air inlet (2) and the air outlet (3) are both set in the vertical direction.

5. The dual-mode photocatalytic reactor based on the biomimetic hollow-globulus structure according to claim 1, characterized in that: The cavity of the protective cover (6) is equipped with 43 30W ultraviolet lamps (7) and 42 40W ultraviolet lamps (7), and each ultraviolet lamp (7) is evenly spaced along the hemispherical surface.

6. The dual-mode photocatalytic reactor based on the biomimetic *Hylocereus equinophorus* structure according to claim 1, characterized in that: The reaction units are made of quartz glass, and the number of reaction units is 42.

7. The dual-mode photocatalytic reactor based on the biomimetic *Hylocereus undatus* structure according to claim 1, characterized in that: The photocatalyst is a Mn-Ce bimetallic MOF catalyst.

8. The dual-mode photocatalytic reactor based on the biomimetic *Hylocereus undatus* structure according to claim 1, characterized in that: The reaction unit includes reaction unit I (41) and reaction unit II (42). The outer diameter of reaction unit I (41) is larger than the outer diameter of reaction unit II (42). The four reaction units II (42) are arranged in a cross shape at the top of the support (5).

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