A solar dual optical path step photoelectric biomass amplification conversion system and method

Abstract

This invention provides a solar dual-path cascaded photoelectric biomass conversion system and method, belonging to the field of solar energy utilization and biomass conversion technology. The system includes a biomass three-element separation and pretreatment unit, a photoelectric reactor, a dual-path light-collecting and splitting unit, and a liquid collection and control unit. Sunlight, after being collected, is split into a first light path and a second light path. The first light path is used to provide heat for pretreatment, while the second light path, after collimation and shaping, forms a parallel or nearly parallel beam that irradiates the photoelectric reactor and drives the oxidation of holocellulose in the anode chamber and the reduction of lignin in the cathode chamber, respectively. The lignin and holocellulose component solutions, after pretreatment separation, are temporarily stored in buffer containers before entering their respective independent circulation loops, operating collaboratively within the same reactor. This invention is suitable for on-site pretreatment and continuous or semi-continuous upgrading conversion of decentralized biomass resources, reducing raw material transportation costs and dependence on external energy supply, and ensuring stable operation.

Description

Technical Field

[0001] This invention relates to the fields of solar energy utilization, biomass resource utilization, and photoelectrocatalytic equipment technology. Specifically, it relates to an engineered system and its operation method that couples solar energy to the biomass pretreatment stage and the subsequent photoelectrochemical conversion stage through dual optical paths, and performs a split-flow synergistic conversion of holocellulose components and lignin components formed after lignocellulose pretreatment. Background Technology

[0002] Lignocellulosic biomass has a wide range of sources, including straw, forestry residues, garden waste, and agricultural processing residues. These raw materials typically exhibit high dispersion, low bulk density, strong seasonality, and large fluctuations in moisture content. Direct long-distance transportation to centralized plants not only incurs high transportation costs but also makes them susceptible to mold, degradation, or compositional fluctuations during storage and transshipment, leading to reduced economic efficiency and stability in subsequent utilization. Therefore, pre-treatment and preliminary quality improvement of dispersed biomass near its production site has become an important approach to improving its resource utilization efficiency.

[0003] Lignocellulosic biomass is composed of components such as cellulose, hemicellulose, and lignin, and these components exhibit significant differences in reactivity, suitable reaction pathways, and target products. In existing processing solutions, pretreatment and component separation are typically completed in one unit, while subsequent conversion takes place in separate external heating or power supply equipment. This results in a long process chain, poor energy matching, and low equipment coupling, making it difficult to adapt to distributed, on-site utilization scenarios.

[0004] In recent years, the use of solar energy to drive chemical conversion processes has attracted widespread attention. Existing schemes for solar-driven biomass conversion mainly fall into three categories: first, using solar energy to provide heat input for pretreatment; second, coupling biomass oxidation and cathodic reduction (or hydrogen evolution) in a photoelectrochemical system; and third, simply combining photothermal and photoelectric processes into the same system. However, for the complete process chain from pretreatment and component separation to split-flow synergistic conversion, existing schemes still have significant shortcomings in terms of engineering integration.

[0005] Especially when applied to distributed on-site quality improvement applications, the above solutions still have at least the following problems: First, the pretreatment unit and the photoelectric reaction unit are usually configured with independent energy supply systems, the solar energy input path is unclear, and the energy distribution is uncontrollable; Second, there is a lack of structural design for the split-flow synergistic conversion of lignin components and holocellulose components in the same equipment to meet the differentiated reaction requirements; Third, existing solutions are mostly focused on laboratory-scale reactor designs, and it is difficult to solve the problems of uneven light exposure, uneven temperature rise, and uneven residence time during scale-up operation. There is also a lack of complete integrated solutions for pumps, valves, sensors, and automatic control required for actual continuous operation.

[0006] Therefore, it is necessary to propose an engineered system capable of adapting to the distributed on-site processing needs of biomass feedstocks and orderly allocating solar energy to the pretreatment and photoelectric conversion stages. This device should possess a clearly defined optical path structure, diversion path, circulation loop, and control logic to achieve stable and continuous cascade conversion operation under fluctuating natural light conditions, and improve the conversion rate and selectivity of the target products. Summary of the Invention

[0007] One of the objectives of this invention is to provide a solar dual-path cascade photovoltaic biomass amplification and conversion system, which aims to pre-treat biomass raw materials on-site, achieve efficient distribution and utilization of solar energy through a dual-path structure, and realize split-flow synergistic conversion within the same reactor to address the difference in reactivity between lignin and holocellulose. At the same time, the system is designed with supporting engineering to ensure the stability of amplification operation and continuous production.

[0008] The second objective of this invention is to provide a method for amplifying and converting biomass using a solar dual-path cascaded photovoltaic system. Through a cascaded process path of pretreatment, separation, diversion, and synergistic conversion, the method achieves stable and continuous conversion of biomass raw materials under fluctuating natural light conditions and improves the conversion rate and selectivity of the target product.

[0009] One of the technical solutions adopted by this invention to achieve its objective is to provide a solar dual-path cascade photoelectric-biomass amplification and conversion system, comprising: The dual-beam-path light-collecting and splitting unit is used to collect sunlight and split it into a first beam and a second beam; the first beam is used to provide heat input for biomass pretreatment; the second beam is shaped into a parallel or nearly parallel beam and then illuminates the light-receiving area of ​​the photoelectrocatalytic reaction unit. The biomass three-element separation and pretreatment unit is used to pretreat lignocellulose biomass and separate lignin component solution and holocellulose component solution; the lignin component solution and holocellulose component solution are respectively connected to the photoelectrocatalytic reaction unit through their respective buffer containers; The photoelectrocatalytic reaction unit includes an anode chamber and a cathode chamber separated by an ion exchange membrane; the anode chamber is the site for the oxidative upgrading reaction of holocellulose components; the cathode chamber is the site for the reduction upgrading reaction of lignin components. The liquid collection and control unit is used to collect the products of the photoelectrocatalytic reaction unit and monitor the system's operating status. Based on the monitoring results, it adjusts at least one of the following: the feed flow rate of the lignin component solution and the holocellulose component solution, the circulation flow rate of the anode chamber and the cathode chamber, and the energy distribution ratio of the first optical path and the second optical path.

[0010] The overall concept and inventive principle of this invention are as follows: This invention provides a system for the scaled-up conversion of solar energy into biomass using a dual-path solar photovoltaic system. Addressing the problems of low solar energy distribution and utilization efficiency during on-site biomass pretreatment, lack of a diversion and synergistic conversion structure for lignin and holocellulose, and difficulty in stable and continuous operation during scale-up, the main improvements are as follows: Firstly, in terms of energy organization, a solar energy collection and splitting structure is adopted, so that the same solar input is distributed at the splitting node to form a first optical path and a second optical path. The first optical path is directed to serve the biomass pretreatment unit, while the second optical path, after collimation and shaping, is directed to serve the photoelectrocatalytic reaction unit, thereby achieving functional decoupling and synergistic matching between pretreatment heating and photoelectrocatalytic light reception.

[0011] Secondly, in terms of material organization, the lignin component solution and holocellulose component solution obtained after pretreatment and solid-liquid separation of lignocellulosic biomass are introduced into the cathode side and anode side of the photoelectric reactor, respectively, and independent circulation loops and independent collection paths are set up, so that the two types of components are converted in parallel along different reaction paths in the same device, avoiding the problem of poor adaptability of traditional single substrate reactors to complex component systems.

[0012] Finally, to address issues such as uniform light reception, heat matching, and operational fluctuation control during engineering scale-up and continuous operation, a collimated parallel light field, a buffer container, and a liquid collection and control unit with monitoring and adjustment functions were introduced into the system. This ensures that the pretreatment stage and the subsequent photoelectric stage can maintain rhythm matching and stable operation under different solar irradiation conditions.

[0013] Furthermore, the dual-path light-collecting and splitting unit includes a solar energy collecting device, an optical path converging / distribution node, and a second optical path collimating component. The optical path converging / distribution node is used to split the sunlight collected by the solar energy collecting device into a first optical path and a second optical path. The second optical path collimating component is used to shape the second optical path to make it a parallel or nearly parallel beam. The setting of the second optical path collimating component helps to improve the uniformity of light reception under amplified operation conditions and reduce the scale effect caused by uneven light field.

[0014] Furthermore, the second optical path collimating component includes one or more of a mirror array, a lens group, a light guide assembly, or a light-shielding and shaping assembly, used to enable the second optical path to form a parallel or approximately parallel light field covering the light-receiving surfaces of the anode chamber and the cathode chamber in the width direction of the photoreactor.

[0015] Furthermore, the biomass three-element separation and pretreatment unit includes a pretreatment reactor and a solid-liquid separation unit; the pretreatment reactor is equipped with a photothermal coupling component on its outer side; the solid-liquid separation unit is used to perform solid-liquid separation on the pretreatment product to obtain a lignin component solution and a holocellulose component solution; the lignin component solution and the holocellulose component solution are each equipped with at least one buffer container.

[0016] Furthermore, the photothermal coupling component includes one or more of a heat-absorbing jacket, a selective absorption coating, or an external heat exchange coil; after the first light path irradiates the photothermal coupling component, heat is transferred to the material system in the pretreatment reactor through conduction or heat exchange medium.

[0017] Furthermore, the buffer container is disposed between the solid-liquid separation unit and the photoelectrocatalytic reaction unit to buffer the fluctuation difference in processing rate between the pretreatment process and the photoelectrochemical conversion process, so that the pretreatment stage and the photoelectrochemical conversion stage can operate at different rates.

[0018] Furthermore, the anode chamber and cathode chamber of the photocatalytic reaction unit are each provided with an independent circulation loop. The circulation loop includes a circulation pump, circulation pipeline and corresponding valve group. Under the action of the liquid collection and control unit, the circulation loop realizes the circulation flow of the reaction liquid and the adjustment of the residence time.

[0019] Furthermore, the photoelectrochemical reactor is a plate or flow channel reactor, with the anode chamber and cathode chamber having independent inlets, independent outlets, and independent circulation loops, and the anode chamber and cathode chamber are separated by an ion exchange membrane, and the reaction solutions on both sides are not directly mixed.

[0020] Furthermore, the liquid collection and control unit includes online monitoring instruments and controllers for monitoring and regulating at least one of the parameters: flow rate, temperature, pressure, liquid level, and light intensity.

[0021] Furthermore, the online monitoring instrument includes one or more of the following: temperature sensor, flow meter, pressure gauge, level gauge, irradiance sensor, pH electrode, and conductivity sensor; the controller adjusts at least one of the following parameters based on the monitoring signal: feed flow rate, circulation flow rate, valve opening, and energy distribution ratio of the first optical path / second optical path.

[0022] The second objective of this invention is to provide a method for amplifying and converting solar energy into biomass using a dual-path photovoltaic system based on the system described in the first objective of this invention, comprising the following steps: S1. The lignocellulose biomass raw material is added to the biomass three-element separation and pretreatment unit and pretreated under the solar thermal input provided by the first optical path. S2. The pretreated system is subjected to solid-liquid separation to obtain lignin component solution and holocellulose component solution; S3. Introduce the holocellulose component solution into the anode chamber and the lignin component solution into the cathode chamber. Under the irradiation of the parallel or nearly parallel beam formed by the second optical path, the oxidation upgrade reaction on the anode side and the reduction upgrade reaction on the cathode side are carried out simultaneously. S4. Monitor the system's operating status through the liquid collection and control unit, and adjust the feed flow rate, circulation flow rate, and / or the energy distribution ratio between the first and second optical paths based on the monitoring results; at the same time, collect the anode products and cathode products respectively.

[0023] This invention achieves the tiered utilization of solar energy and the efficient, targeted conversion of biomass components through a tiered process path of pretreatment, separation, diversion, and synergistic conversion. In this method, the first optical path converts solar energy into thermal energy, serving the pretreatment stage and causing the lignocellulose structure to deconstruct and achieve solid-liquid separation. The second optical path, after collimation and shaping, forms parallel or nearly parallel beams, simultaneously driving the holocellulose oxidation upgrade reaction in the anode chamber and the lignin reduction upgrade reaction in the cathode chamber, enabling the two types of components to be converted in parallel along different reaction paths within the same system. Through real-time monitoring and coordinated adjustment of the feed flow rate, circulation flow rate, and energy distribution ratio of the two optical paths by the liquid collection and control unit, the system can maintain the rhythm matching and stable operation of the pretreatment and photoelectric conversion stages under outdoor conditions with fluctuating natural light, thereby maintaining a high conversion rate and selectivity of the target product in continuous or semi-continuous operation.

[0024] Furthermore, in step S1, the lignocellulosic biomass raw material includes one or more of crop straw, forestry residues, or other lignocellulosic raw materials.

[0025] Furthermore, in step S1, the pretreatment temperature is 40-90℃, the pretreatment time is 30-240 min, and the pretreatment medium is a dilute alkaline solution.

[0026] Furthermore, in step S3, the applied bias voltage of the anode chamber and the cathode chamber is 0.5-1.5V, and the incident light intensity is 50-150mW / cm². 2 The residence time of the reaction solution in the reactor is 2-24 hours.

[0027] Furthermore, in step S4, the liquid collection and control unit adjusts the feed flow rate, circulation flow rate and / or the energy distribution ratio between the first optical path and the second optical path in conjunction with at least one of the parameters: pretreatment reactor temperature, photoelectrochemical reactor temperature, anode circulation flow rate, cathode circulation flow rate and irradiance.

[0028] Furthermore, the circulation flow rate is adjusted based on solar irradiance, reaction temperature, or target residence time. The adjustment methods include: when the buffer container level is above the upper limit, the controller increases the circulation flow rate of the corresponding circulation loop; when the target residence time needs to be extended, the controller decreases the circulation flow rate. Preferably, the anode circulation flow rate adjustment range is 4-6 mL / min, and the cathode circulation flow rate adjustment range is 2.5-4 mL / min. It is understood that when scale-up is required, the above flow rate ranges are scaled up proportionally according to the reactor volume ratio or electrode area ratio.

[0029] Furthermore, the energy distribution ratio between the first and second optical paths is adjusted according to the temperature requirements of the pretreatment unit and the light reception requirements of the photoelectric reaction unit to maintain the synergistic matching between pretreatment and photoelectric reaction. Specifically, the adjustment method of the energy distribution ratio includes: when the temperature of the pretreatment reactor is lower than the set value, increasing the distribution ratio of the first optical path or decreasing the pretreatment feed rate; when the temperature of the photoelectric reactor is lower than the set value and the irradiance is sufficient, increasing the distribution ratio of the second optical path. Preferably, the energy distribution ratio L1 / L2 between the first and second optical paths is set to 4-6:1. When the solar irradiance fluctuates, the controller adjusts the energy distribution ratio between the first and second optical paths according to the real-time irradiance to maintain the temperature of the pretreatment reactor within the range of 55-65℃ and the temperature of the photoelectric reactor within the range of 28-35℃.

[0030] Furthermore, the method operates continuously or semi-continuously under natural sunlight conditions; when solar irradiance fluctuates, the pretreatment temperature is maintained within a set range by adjusting the feed flow rate, circulation flow rate, and / or energy distribution ratio, and the operating state of the photoelectrorea is kept stable.

[0031] The system provided by this invention can be directly deployed near agricultural and forestry waste production sites, utilizing natural sunlight as the sole external source of light and heat. Addressing the problems of dispersed biomass raw material sources, long transportation distances, and the unsuitability of long-term storage of wet-based raw materials, this invention reduces the proportion of low-value raw materials directly transported off-site by implementing pretreatment and preliminary upgrading at the raw material level, while simultaneously preventing mold or degradation during storage and transportation. This system and method are applicable to the on-site conversion of various lignocellulosic biomass, including straw, forestry residues, and garden waste, and possess good economic viability and promising prospects for widespread application.

[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention provides a solar dual-path cascade photoelectric biomass amplification system. Through a dual-path structure, pretreatment heating and photoelectric reaction light reception are coordinated and matched under the same solar energy input. By implementing separate feeding, independent circulation, and independent collection of lignin and holocellulose components, the two types of components with different activities are converted in parallel along their respective suitable reaction paths within the same reactor. Combined with parallel or near-parallel light field design and integrated liquid collection and control unit, the system effectively solves the common problems of uneven light reception, uneven temperature rise, and uneven residence time during amplification. Comparative experiments show that the dual-path structure significantly improves the conversion rate of holocellulose compared to the single-path structure, and separate feeding is more conducive to improving the conversion rates of anode and cathode products than mixed feeding. The device can operate continuously for more than 24 hours under fluctuating natural light conditions, with small flow rate fluctuations and temperature fluctuations controlled within a reasonable range, providing a basis for extending from laboratory scale to engineering scale.

[0033] (2) This invention provides a method for the scaled-up conversion of biomass through a dual-path solar photovoltaic process. This method achieves the directional conversion of biomass components through a cascaded process path of pretreatment, separation, diversion, and synergistic conversion. The first optical path provides thermal energy for pretreatment, while the second optical path, after collimation, simultaneously drives the holocellulose oxidation upgrade reaction on the anode side and the lignin reduction upgrade reaction on the cathode side. The feed flow rate, circulation flow rate, and energy distribution ratio of the dual optical paths are monitored and adjusted in real time by a liquid collection and control unit. This method can maintain the rhythm matching and stable operation of the pretreatment and photovoltaic conversion stages under fluctuating natural light conditions. This method is flexible in operation and highly adaptable to raw materials, providing an efficient, stable, and continuously operating technical solution for the distributed on-site conversion of lignocellulose biomass, and has good prospects for promotion and application. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the overall structure of the solar dual-path cascade photoelectric biomass amplification conversion system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the photoelectrocatalytic photoelectrorea and dual-loop structure in the system provided in the embodiments of the present invention; Figure 3 This is a schematic diagram of the dual-optical-path light collection, beam splitting, and collimation shaping system provided in the embodiments of the present invention. Detailed Implementation

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] like Figure 1-3 As shown, this embodiment of the invention provides a solar dual-path cascade photoelectric biomass amplification and conversion system, including a dual-path light collection and splitting unit, a biomass three-element separation and pretreatment unit, a photoelectrocatalytic reaction unit, and a liquid collection and control unit.

[0037] The dual-path light-collecting and splitting unit includes a solar energy collecting device, a light path converging / distribution node, and a second light path collimating component. The solar energy collecting device collects and converges sunlight. The light path converging / distribution node is located on the light-emitting side of the solar energy collecting device and is used to split the converged sunlight into a first light path and a second light path. The first light path provides heat input for biomass pretreatment; the second light path collimating component is located on the propagation path of the second light path and uses a mirror array, lens group, or light guide shaping assembly to shape the second light path into a parallel or nearly parallel beam to uniformly illuminate the light-receiving area of ​​the photoelectrocatalytic reaction unit.

[0038] The biomass three-element separation and pretreatment unit includes a pretreatment reactor and a solid-liquid separation unit. A photothermal coupling component is installed on the outside of the pretreatment reactor to receive solar energy from the first optical path and provide heat for the pretreatment process. The photothermal coupling component employs a heat-absorbing jacket, a selective absorption coating, or an external heat exchange coil. The inlet of the solid-liquid separation unit is connected to the outlet of the pretreatment reactor for solid-liquid separation of the pretreated slurry, using plate and frame filtration, centrifugation, or vacuum filtration. The resulting lignin and holocellulose solutions are temporarily stored in their respective buffer containers. The buffer containers are designed to reduce the time difference between the pretreatment process and the subsequent photoelectric conversion process; one or more buffer containers can be configured for each component.

[0039] The photoelectrocatalytic reaction unit includes a photoreactor, which comprises an anode chamber and a cathode chamber separated by an ion-exchange membrane. The anode chamber is the site of the oxidative upgrading reaction of the holocellulose component, and the cathode chamber is the site of the reduction upgrading reaction of the lignin component. The photoreactor has a plate or flow channel structure, with a photothermal coupling module mounted above it to receive heat input from the second optical path. The anode and cathode chambers each have independent circulation loops. The holocellulose component solution is metered into the anode chamber circulation loop, and the lignin component solution is metered into the cathode chamber circulation loop. The anode circulation loop includes an anode circulation pump, circulation piping, and corresponding valve groups. The outlet of the anode chamber is connected to the inlet of the anode circulation pump via the circulation piping, and the outlet of the anode circulation pump returns to the inlet of the anode chamber via the circulation piping, forming a closed loop. The cathode circulation loop is similar, including a cathode circulation pump and corresponding valve groups. The circulation loops are used to achieve the circulating flow of the reaction solution to enhance mass transfer and regulate residence time.

[0040] The liquid collection and control unit includes online monitoring instruments and a controller. The online monitoring instruments may include one or more of the following: temperature sensor, flow meter, pressure gauge, level gauge, irradiance sensor, pH electrode, and conductivity sensor. The controller is signal-connected to each instrument and each actuator (metering pump, circulating pump, valve group, spectrophotometric adjustment mechanism) to receive monitoring signals and output control commands. The controller can adjust at least one of the following based on the monitoring results: the feed flow rate of the lignin component solution and holocellulose component solution, the circulating flow rate of the anode and cathode chambers, and the energy distribution ratio of the first and second optical paths.

[0041] The working principle of the above system is as follows: Through a tiered process path of pretreatment, separation, diversion, and synergistic conversion, the system achieves tiered utilization of solar energy and efficient directional conversion of biomass components. The first optical path converts solar energy into thermal energy, serving the pretreatment stage, deconstructing the lignocellulose structure and achieving solid-liquid separation. The separated lignin component solution and holocellulose component solution are temporarily stored in their respective buffer containers to reduce the time difference between the pretreatment and photoelectric conversion stages. The second optical path, after collimation and shaping, forms parallel or nearly parallel beams, simultaneously driving the holocellulose oxidation upgrade reaction in the anode chamber and the lignin reduction upgrade reaction in the cathode chamber, enabling the two types of components to be converted in parallel along different reaction paths within the same system. Through real-time monitoring and linkage adjustment of the feed flow rate, circulation flow rate, and energy distribution ratio of the two optical paths by the liquid collection and control unit, the system can maintain time matching and stable operation of the pretreatment and photoelectric conversion stages under outdoor conditions with fluctuating natural light, thereby maintaining a high target product conversion rate and selectivity in continuous or semi-continuous operation.

[0042] The present invention will be further described below with reference to specific embodiments, but these are not intended to limit the scope of the invention.

[0043] Example 1 Poplar wood chips were selected as the lignocellulose biomass raw material, pre-crushed and sieved through a 100-mesh sieve, with the moisture content controlled to be below 10%. 100 g of poplar wood chips were weighed and added to a pretreatment reactor, along with 300 g of a 5 wt% potassium hydroxide aqueous solution at a solid-liquid mass ratio of 1:3. The mixture was then stirred until homogeneous. The reactor was irradiated with a photothermal coupling element on the outside of the pretreatment reactor via the first optical path L1 to maintain the internal temperature at 60℃ for 120 min, with a stirring speed of 300 rpm. After pretreatment, the slurry was introduced into a solid-liquid separation unit, where plate and frame filtration was used for solid-liquid separation. After settling, the filtrate yielded a lignin component solution, and the filter residue was washed and re-prepared to obtain a holocellulose component solution. Both were temporarily stored in their respective buffer containers.

[0044] The lignin component solution had a volume of 180 mL and a pH of 12.3; the holocellulose component solution had a volume of 220 mL and a pH of 11.6. The holocellulose component solution was pumped into the anode chamber circulation loop via a metering pump. A TiO2 photoanode was used, with an effective light-receiving area of ​​500 cm². 2 The effective volume of the anode chamber is 650 mL, and the anolyte is a 1 mol / L KOH solution. The lignin component solution is pumped to the cathode chamber circulation loop via a metering pump. The cathode is a GaN / Si photocathode with an effective light-receiving area of ​​500 cm². 2 The effective volume of the cathode chamber is 650 mL, and the cathode electrolyte is a 0.5 mol / L H₂SO₄ solution. A proton exchange membrane, which is a Nafion-type membrane, is installed between the anode and cathode chambers. The anode and cathode are connected by an external circuit, with an applied bias voltage set to 0.8 V.

[0045] The second optical path L2, after being collimated and shaped by a mirror array and lens group, forms a parallel or nearly parallel beam that simultaneously illuminates the light-receiving areas of the anode and cathode chambers, with an incident irradiance of 100 mW / cm². 2 During operation, the energy distribution ratio L1 / L2 between the first and second optical paths was set to 5:1; the anode circulation flow rate was set to 5 mL / min, the cathode circulation flow rate to 3 mL / min, and the feed flow rate to 1.5 mL / min; the reaction lasted for 8 hours. The controller monitored the pretreatment vessel temperature T1, reactor temperature T2, anode flow rate Q1, cathode flow rate Q2, and irradiance I in real time. When T1 was below 58℃, the controller increased the first optical path distribution ratio; when T2 was below 30℃, the controller increased the second optical path distribution ratio; when the liquid level in any buffer container was above the upper limit, the feed flow rate at the front end was reduced or the corresponding circulation flow rate was increased accordingly.

[0046] After the reaction, the liquid phase products on the anolyte and cathode sides were analyzed separately. The anolyte product was quantitatively analyzed using high-performance liquid chromatography (HPLC), while the cathode product was qualitatively and quantitatively analyzed using gas chromatography-mass spectrometry (GC-MS). The results showed that the holocellulose component conversion rate was 72%, with an anolyte target product selectivity of 80%; the lignin component conversion rate was 42%, with an anolyte target product selectivity of 72%. The anolyte Faraday efficiency was 83%, and the cathode Faraday efficiency was 85%. During 8 hours of continuous operation, the inlet and outlet flow rate fluctuations of the reactor were both less than 5%, and the system temperature fluctuations were controlled within ±2℃, indicating that the device can achieve relatively stable dual-path cascade synergistic operation.

[0047] Example 2 This embodiment increases the amount of raw materials added based on Embodiment 1 to verify the stability of the device under continuous operation.

[0048] The amount of raw poplar wood chips added was increased to 500 g, and pretreatment was carried out according to the same solid-liquid ratio and pretreatment medium concentration as in Example 1. The material was then continuously fed to the photoelectrocatalytic reaction unit through a buffer container. Both the first and second light paths used natural sunlight collected before being input into the system, with an average daytime irradiance of 70-110 mW / cm². 2 The controller adjusts the L1 / L2 energy distribution ratio according to real-time changes in irradiance intensity, maintaining the pretreatment vessel temperature within the range of 55-65℃ and the photoelectrochemical reactor temperature within the range of 28-35℃.

[0049] The device operated continuously for 24 hours, including 18 hours during the day and 6 hours of semi-continuous operation at night using a buffer container to temporarily store the component solution. During operation, the anode circulation flow rate was controlled within the range of 4-6 mL / min, and the cathode circulation flow rate was controlled within the range of 2.5-4 mL / min. Analysis of the product distribution at different time points during continuous operation showed that the target product selectivity on the anode side remained within the range of 76%-81%, and the target product selectivity on the cathode side remained within the range of 68%-73%. Before and after 24 hours of operation, no significant damage was observed to the proton exchange membrane, and no significant detachment or blockage was observed on the electrode surface. The total system flow rate fluctuation was less than 8%. These results indicate that the device described in this invention possesses the capability for continuous or semi-continuous stable operation and can adapt to distributed on-site quality improvement scenarios under conditions of fluctuating natural solar irradiance.

[0050] Comparative Example 1 This comparative example uses the same raw material conditions, pretreatment conditions, reactor structure and running time as Example 1. The difference is that the collimation and directional light transmission structure of the second optical path L2 is removed, and only the first optical path L1 is retained for pretreatment heating. The photoelectric reaction stage no longer receives collimated parallel light irradiation, but only relies on natural ambient scattered light and system stray incident light. All other conditions remain unchanged.

[0051] The results showed that under single-path conditions, the conversion rate of holocellulose decreased to 51%, and the selectivity of the target product at the anode decreased to 59%; the conversion rate of lignin decreased to 28%, and the selectivity of the target product at the cathode decreased to 54%. Meanwhile, the distribution differences of liquid phase products at different locations within the reactor increased, indicating that eliminating the second light path resulted in insufficient light exposure and decreased light uniformity, which is detrimental to the stable conduct of the photoelectric conversion reaction.

[0052] Comparative Example 2 The difference between this comparative example and Example 1 is that the pretreated lignin component solution and holocellulose component solution are not separated, but are mixed and sent into the same reaction loop at the same time, while the other light, flow rate and running time remain the same.

[0053] The results showed that although the overall conversion rate could reach 60% under mixed feed conditions, the selectivity of the target product on the anode side was only 52%, and the selectivity on the cathode side was only 49%. Furthermore, the product distribution was complex, significantly increasing the difficulty of subsequent separation and purification. This indicates that, compared to changes in light exposure conditions, the substrate competition for adsorption and reaction pathway interference caused by mixed feed had a more significant adverse impact on the formation of the target product. This invention, by separately feeding, independently circulating, and independently collecting the lignin and holocellulose components, is beneficial for improving the controllability of the reaction pathway and the selectivity of the target product.

[0054] Comparative Example 3 The difference between this comparative example and Example 1 is that the buffer container between the solid-liquid separation unit and the photoelectrocatalytic reaction unit is removed, so that the pretreatment stage and the photoelectrochemical conversion stage are directly connected in series.

[0055] The results show that when solar irradiance fluctuates, the mismatch between the cycle times of the preceding and following processes is significantly amplified, leading to increased fluctuations in the liquid levels of the anode and cathode circulation loops. Localized instability in the liquid supply occurs after 6 hours of continuous operation. This indicates that the buffer container helps to mitigate the cycle time difference between the pretreatment and photoelectric conversion processes, thereby improving the overall operational stability of the system.

[0056] The conversion rate and selectivity in the above embodiments were calculated according to conventional methods in the art; each group of experiments was repeated at least 3 times, and the average value was taken as the result. The system energy consumption was statistically calculated as the sum of the applied electrical work and auxiliary pump work in the process of processing a unit mass of raw material.

[0057] In summary, this invention, through a dual-beam-path cascade utilization and component-splitting synergistic conversion design, achieves stable and continuous operation of biomass pretreatment and photoelectric conversion under fluctuating natural light conditions. Data from the examples and comparative cases show that the dual-beam-path structure significantly improves the conversion rate of holocellulose and lignin compared to the single-beam-path structure; split feeding significantly improves the conversion rate and selectivity of the target products at the anode and cathode compared to mixed feeding; and the buffer container effectively decouples the timing differences between pretreatment and photoelectric conversion, significantly extending the continuous and stable operation time. This device and method have the foundation for scaling up from the laboratory scale to the engineering scale, providing a feasible technical path for the distributed in-situ conversion of lignocellulosic biomass, and possesses good prospects for promotion and application.

[0058] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the content of this specification should be included within the protection scope of the present invention.

Claims

1. A system for amplified solar dual-path cascade photoelectric-biomass conversion, characterized in that, include: The dual-optical-path light-collecting and splitting unit is used to collect sunlight and split it into a first optical path and a second optical path; the first optical path is used to provide heat input for biomass pretreatment. The second optical path is shaped into a parallel or nearly parallel beam before irradiating the light-receiving area of ​​the photocatalytic reaction unit; The biomass three-element separation and pretreatment unit is used to pretreat lignocellulose biomass and separate lignin component solution and holocellulose component solution. The lignin component solution and the holocellulose component solution are respectively connected to the photoelectrocatalytic reaction unit through their respective buffer containers; The photoelectrocatalytic reaction unit includes an anode chamber and a cathode chamber separated by an ion exchange membrane; the anode chamber is the site for the oxidative upgrading reaction of holocellulose components; the cathode chamber is the site for the reduction upgrading reaction of lignin components. The liquid collection and control unit is used to collect the products of the photoelectrocatalytic reaction unit and monitor the system's operating status. Based on the monitoring results, it adjusts at least one of the following: the feed flow rate of the lignin component solution and the holocellulose component solution, the circulation flow rate of the anode chamber and the cathode chamber, and the energy distribution ratio of the first optical path and the second optical path.

2. The system according to claim 1, characterized in that, The dual-path light-collecting and splitting unit includes a solar energy collecting device, a light path converging / distribution node, and a second light path collimating component. The light path converging / distribution node is used to split the sunlight collected by the solar energy collecting device into a first light path and a second light path. The second light path collimating component is used to shape the second light path to make it a parallel or nearly parallel beam.

3. The system according to claim 1, characterized in that, The biomass three-element separation and pretreatment unit includes a pretreatment reactor and a solid-liquid separation unit; A photothermal coupling component is installed on the outside of the pretreatment reactor; The solid-liquid separation unit is used to separate the pretreatment product into solid and liquid components to obtain lignin component solution and holocellulose component solution; The lignin component solution and the holocellulose component solution are each equipped with at least one buffer container.

4. The system according to claim 1, characterized in that, The anode and cathode chambers of the photoelectrocatalytic reaction unit are each equipped with an independent circulation loop. The circulation loop includes a circulation pump, circulation pipeline, and corresponding valve group. Under the action of the liquid collection and control unit, the circulation loop realizes the circulation flow of the reaction liquid and the adjustment of the residence time.

5. The system according to claim 1, characterized in that, The liquid collection and control unit includes an online monitoring instrument and a controller. The online monitoring instrument is used to monitor at least one of the parameters of flow rate, temperature, pressure, liquid level and light intensity, and the controller adjusts the parameters according to the monitoring results.

6. A method for solar dual-path cascaded photoelectric biomass amplification and conversion based on the system according to any one of claims 1-5, characterized in that, Includes the following steps: S1. The lignocellulose biomass raw material is added to the biomass three-element separation and pretreatment unit and pretreated under the solar thermal input provided by the first optical path. S2. The pretreated system is subjected to solid-liquid separation to obtain lignin component solution and holocellulose component solution; S3. Introduce the holocellulose component solution into the anode chamber and the lignin component solution into the cathode chamber. Under the irradiation of the parallel or nearly parallel beam formed by the second optical path, the oxidation upgrade reaction on the anode side and the reduction upgrade reaction on the cathode side are carried out simultaneously. S4. Monitor the system's operating status through the liquid collection and control unit, and adjust the feed flow rate, circulation flow rate, and / or the energy distribution ratio between the first and second optical paths based on the monitoring results; The anode products and cathode products were collected separately.

7. The method according to claim 6, characterized in that, In step S1, the pretreatment temperature is 40-90℃, the pretreatment time is 30-240 min, and the pretreatment medium is a dilute alkaline solution.

8. The method according to claim 6, characterized in that, In step S3, the applied bias voltage to the anode and cathode chambers is 0.5-1.5V, and the incident light intensity is 50-150mW / cm². 2 The residence time of the reaction solution in the reactor is 2-24 hours.

9. The method according to claim 6, characterized in that, In step S4, the liquid collection and control unit adjusts the feed flow rate, circulation flow rate and / or the energy distribution ratio between the first optical path and the second optical path according to at least one of the parameters: pretreatment reactor temperature, photoelectrophotoreactor temperature, anode circulation flow rate, cathode circulation flow rate and irradiance.

10. The method according to claim 6, characterized in that, The method operates continuously or semi-continuously under natural sunlight conditions. When the solar irradiance fluctuates, the liquid collection and control unit adjusts the feed flow rate, circulation flow rate, and / or energy distribution ratio to maintain the pretreatment temperature within a set range and keep the operation of the photoelectrorea stable.

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