High-quality biological fuel oil production system driven by net zero carbon solar energy

Abstract

The invention discloses a net zero-carbon solar-driven high-quality bio-fuel oil production system, and relates to the technical field of biomass energy conversion. The system comprises: a hydrothermal liquefaction reactor for a hydrothermal liquefaction reaction of biomass; the photovoltaic electric heating device is used for heating the reactor; the solar molten salt device is used for heat preservation of the reactor; the waste heat recovery device is connected with an outlet of the reactor to recover waste heat; the separation device is connected with an outlet of the waste heat recovery device and used for separating biological crude oil and organic wastewater; the biological hydrogen production device is used for producing hydrogen by utilizing wastewater photosynthesis; the hydrogenation upgrading device is used for producing biological fuel oil by using biological crude oil and hydrogen; and the controller is in communication connection with each device. Through solar heat supply and photosynthetic biological hydrogen production, dual dependence on fossil energy is avoided, and net zero carbon emission of a high-quality biofuel production whole chain is achieved.

Description

Technical Field

[0001] This invention relates to the field of biomass energy conversion technology, and in particular to a net-zero carbon solar-driven high-quality biofuel production system. Background Technology

[0002] In the field of biomass energy conversion, hydrothermal liquefaction technology, as a method that simulates the natural oil formation process, can rapidly convert biomass into bio-crude oil under high temperature and high pressure, showing promising application prospects. However, this technology still faces several key issues that urgently need to be addressed in practical applications.

[0003] On the one hand, the hydrothermal reaction process requires a continuous supply of large amounts of heat energy, currently relying mainly on traditional fossil fuels as the heating source, resulting in high carbon emissions during production. On the other hand, the bio-crude oil produced by hydrothermal liquefaction is of low quality, requiring hydrotreating to improve its fuel performance. However, the hydrogen needed for hydrotreating also mainly comes from fossil fuel-based hydrogen production, further exacerbating the system's carbon footprint. This dual reliance on fossil fuels makes it difficult for the entire process chain to achieve fundamental low-carbon goals, running counter to global carbon neutrality objectives. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a net-zero carbon solar-driven high-quality biofuel production system that can eliminate the dual dependence on fossil fuels through solar heating and photosynthetic biohydrogen production, achieving net-zero carbon emissions across the entire high-quality biofuel production chain.

[0005] To achieve the above objectives, the present invention provides a net-zero carbon solar-driven high-quality biofuel production system, comprising: A hydrothermal liquefaction reactor is used to receive biomass raw materials for hydrothermal liquefaction reaction to obtain reaction products; A photovoltaic electric heating device is used to heat the hydrothermal liquefaction reactor; A solar-powered molten salt device is used to heat and maintain the temperature of the hydrothermal liquefaction reactor. The waste heat recovery device has its inlet connected to the reaction product outlet of the hydrothermal liquefaction reactor and is used to recover the waste heat of the reaction products. The separation device has an inlet connected to the outlet of the waste heat recovery device, and is used to separate the reaction products after waste heat absorption into bio-crude oil and organic wastewater. The biohydrogen production device has its inlet connected to the wastewater outlet of the separation device, and is used to produce hydrogen from the organic wastewater through fermentation by photosynthetic bacteria. The hydro-upgrading unit has a crude oil inlet connected to the crude oil outlet of the separation unit and a hydrogen inlet connected to the hydrogen outlet of the bio-hydrogen production unit, and is used to hydro-upgrade the bio-crude oil into biofuel. The controller is communicatively connected to the hydrothermal liquefaction reactor, photovoltaic electric heating device, solar molten salt device, waste heat recovery device, separation device, biohydrogen production device, and hydrogenation and upgrading device.

[0006] Optionally, the controller is used to: During the heating stage of the hydrothermal liquefaction reactor, the photovoltaic electric heating device is controlled to heat the hydrothermal liquefaction reactor. During the heat preservation stage of the hydrothermal liquefaction reactor, the solar molten salt device is controlled to provide heat and maintain the temperature of the hydrothermal liquefaction reactor.

[0007] Optionally, the controller is used to perform maximum power point tracking control on the photovoltaic electric heating device to maximize the power output of the photovoltaic array in the photovoltaic electric heating device.

[0008] Optionally, the controller is used to: Acquire system operating parameters; the system operating parameters include meteorological data, hydrothermal liquefaction reaction temperature curves, and material heat capacity; The system operating parameters are input into a pre-trained prediction model to obtain prediction results of energy supply and demand trends within a preset future time period; Based on the prediction results, an output power allocation strategy is determined; The operating status of the photovoltaic electric heating device, the solar molten salt device, and the waste heat recovery device are adjusted according to the output power distribution strategy.

[0009] Optionally, in adjusting the operating state of the solar molten salt device according to the output power distribution strategy, the controller is specifically used for: Monitor the temperature and circulation flow rate of the molten salt in the solar molten salt device; The control targets for temperature and circulation flow rate are determined based on the output strategy of the solar molten salt device in the output power distribution strategy. According to the control objective, the valve opening degree of the molten salt circulation pipeline and / or the rotation speed of the circulation pump in the solar molten salt device are dynamically adjusted.

[0010] Optionally, in adjusting the operating state of the waste heat recovery device according to the output power distribution strategy, the controller is specifically used for: Obtain product operating parameters to characterize the type, temperature, and flow rate of the reaction products; Based on the pre-stored operating condition parameter mapping table, query the expected waste heat recovery value corresponding to the product operating condition parameters; Obtain the actual waste heat recovery value of the waste heat recovery device; Based on the expected waste heat recovery value and the actual waste heat recovery value, the speed of the heat exchange medium circulation pump and / or the opening of the flow control valve in the waste heat recovery device are dynamically adjusted.

[0011] Optionally, the production system further includes a human-machine interface that is communicatively connected to the controller. The human-machine interface is used to receive input commands from operators and display the operating status parameters and alarm information of the hydrothermal liquefaction reactor, photovoltaic electric heating device, solar molten salt device, waste heat recovery device, biohydrogen production device, and hydrogenation and upgrading device.

[0012] Optionally, the waste heat recovery device is connected to the bio-hydrogen production device via a heat exchange pipeline to utilize the waste heat to preheat and / or maintain the reaction temperature of the culture medium in the bio-hydrogen production device.

[0013] Optionally, in terms of maximum power point tracking control of the photovoltaic electric heating device, the controller is specifically used for: Monitor the output voltage and current of the photovoltaic array in the photovoltaic electric heating device; Based on the output voltage and current, voltage perturbations are periodically applied to the photovoltaic array; Based on the direction of change in the output power of the photovoltaic array after the voltage disturbance is applied, the direction of the voltage disturbance is dynamically adjusted to lock the operating point of the photovoltaic array at the maximum power point.

[0014] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: The net-zero carbon solar-driven high-quality biofuel production system provided by this invention systematically integrates a hydrothermal liquefaction reactor, a photovoltaic electric heating device, a solar-powered molten salt device, a waste heat recovery device, a separation device, a bio-hydrogen production device, a hydrogenation and upgrading device, and a controller, constructing a complete energy and material cycle system. This fundamentally solves the problem of dual dependence on fossil fuels in traditional biomass hydrothermal liquefaction technology, namely, the high carbon emission challenges caused by heating relying on fossil fuels and hydrogenation relying on fossil fuel hydrogen production.

[0015] This system utilizes solar energy as a heat source by incorporating photovoltaic electric heating and solar-powered molten salt devices, replacing the traditional methods that rely on coal-fired or natural gas-fired electric heating and combustion heating. This eliminates the root cause of carbon emissions at the energy input end. Simultaneously, the system uses a bio-hydrogen production unit to convert organic wastewater separated by the separation unit into hydrogen production feedstock. This feedstock is then fermented by photosynthetic bacteria to produce green hydrogen, providing a clean hydrogen source for the hydrogenation and upgrading unit, thus replacing high-carbon fossil fuel-based hydrogen production at its source. This dual green substitution of thermal and hydrogen energy brings the external fossil energy input to near zero throughout the entire process chain. Combined with the carbon-neutral nature of biomass itself, this ultimately achieves "net-zero carbon emissions" throughout the entire life cycle, resulting in significant environmental benefits. Attached Figure Description

[0016] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0017] Figure 1 This is a schematic diagram of the modular structure of a net-zero carbon solar-driven high-quality biofuel production system according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the hardware structure of a net-zero carbon solar-driven high-quality biofuel production system according to an embodiment of the present invention. Figure 3 This is a schematic diagram of a human-computer interaction interface shown in an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0019] This invention converts biomass feedstock into bio-crude oil through hydrothermal liquefaction, and then performs deep deoxygenation and structural reconstruction on the bio-crude oil through hydrotreating to produce a high-quality biofuel. High quality refers to a fuel calorific value of not less than 45 MJ / kg. This high-quality biofuel is mainly composed of hydrocarbons, with a significantly reduced content of oxygen-containing functional groups. When blended with petrochemical diesel at a volume ratio of 10% (v / v), the resulting blended fuel achieves 95%–100% of the power output performance of pure diesel fuel in an internal combustion engine. This blended fuel closely resembles aviation kerosene in terms of energy density, combustion performance, and application adaptability, and can be used as a bio-aviation kerosene or aviation kerosene substitute.

[0020] Please see Figure 1 and Figure 2 , Figure 1 A schematic diagram of the modular structure of a net-zero carbon solar-powered high-quality biofuel production system. Figure 1 The dashed line in the middle represents a communication connection; Figure 2 This is a schematic diagram of the hardware structure of the production system.

[0021] A net-zero carbon solar-powered high-quality biofuel production system, including: Hydrothermal liquefaction reactor 1 is used to receive biomass raw materials for hydrothermal liquefaction reaction to obtain reaction products; Photovoltaic electric heating device 2 is used to heat the hydrothermal liquefaction reactor 1; The solar molten salt device 3 is used to heat and keep warm the hydrothermal liquefaction reactor 1. The waste heat recovery device 4 has its inlet connected to the reaction product outlet of the hydrothermal liquefaction reactor 1, and is used to recover the waste heat of the reaction products. The separation device 5 is connected to the outlet of the waste heat recovery device 4 at its inlet, and is used to separate the reaction products after the waste heat is absorbed into bio-crude oil and organic wastewater. The biohydrogen production unit 6 has its inlet connected to the wastewater outlet of the separation unit 5, and is used to produce hydrogen from organic wastewater through photosynthetic bacteria fermentation. The hydro-upgrading unit 7 has its crude oil inlet connected to the crude oil outlet of the separation unit 5 and its hydrogen inlet connected to the hydrogen outlet of the bio-hydrogen production unit 6. It is used to hydro-upgrade bio-crude oil into biofuel. The controller 8 is communicatively connected to the hydrothermal liquefaction reactor 1, the photovoltaic electric heating device 2, the solar molten salt device 3, the waste heat recovery device 4, the separation device 5, the biohydrogen production device 6, and the hydrogenation and upgrading device 7.

[0022] This invention achieves net-zero carbon conversion of biomass feedstock into high-quality biofuel through a highly integrated energy and material recycling pathway. The system constructs a complete closed loop from feedstock input to final product output, with all core units working collaboratively to form an energy-self-sufficient, material-self-sufficient, and environmentally friendly production system.

[0023] The hydrothermal liquefaction reactor 1 receives pretreated biomass feedstock, such as crushed and homogenized wet waste slurry, for hydrothermal liquefaction. This process simulates the natural petroleum formation process, utilizing a high-temperature, high-pressure environment to rapidly convert biomass into a reaction mixture with bio-crude oil as the primary product. To drive the hydrothermal liquefaction reaction and fundamentally replace traditional fossil fuel heating, the system innovatively incorporates a photovoltaic electric heating device 2 and a solar molten salt device 3. The photovoltaic electric heating device 2 uses electricity generated by solar photovoltaic power generation to drive an electric heater to heat the hydrothermal liquefaction reactor 1, making it particularly suitable for the initial heating stage where a rapid supply of high-grade heat energy is required. The solar molten salt device 3 heats the molten salt medium through a solar collector for heat storage. After the hydrothermal liquefaction reactor 1 reaches the target reaction temperature, it serves as the main heat source for long-term, high-precision heating and heat preservation, ensuring the core reaction continues under stable and suitable temperature conditions.

[0024] To achieve tiered energy utilization and maximize efficiency within the system, a waste heat recovery device 4 is installed. The inlet of this device is directly connected to the reaction product outlet of the hydrothermal liquefaction reactor 1, used to recover the large amount of sensible heat carried by the high-temperature products after the reaction. For example... Figure 2 As shown, the material output pump 11, which is connected to the controller 8, transports the reaction products from the hydrothermal liquefaction reactor 1 to the waste heat recovery device 4. The recovered heat can be used for external heating (such as plant heating) or can be reintroduced into the system for reuse, thereby reducing the overall external energy consumption of the system.

[0025] The reaction products, after being cooled by the waste heat recovery device 4, are transported to the separation device 5. The inlet of the separation device 5 is connected to the outlet of the waste heat recovery device 4. Its core function is to effectively separate the treated reaction products, mainly obtaining crude bio-crude oil and aqueous products rich in organic matter, i.e., high-concentration organic wastewater.

[0026] The system thoroughly transforms the separated organic wastewater into a resource-efficient form and transports it to the biological hydrogen production unit 6. The inlet of the biological hydrogen production unit 6 is connected to the wastewater outlet of the separation unit 5. Inside, it utilizes a combination of specific dark fermentation hydrogen-producing bacteria and photosynthetic bacteria that utilize sunlight energy to ferment and treat the organic wastewater, converting the organic matter in the wastewater into clean hydrogen gas.

[0027] Ultimately, the system enhances the quality of the biofuel through the hydrotreating unit 7. The crude oil inlet of the hydrotreating unit 7 is connected to the crude oil outlet of the separator 5 to receive the separated crude biofuel; its hydrogen inlet is connected to the hydrogen outlet of the bio-hydrogen production unit 6 to receive the system's self-produced green hydrogen. Inside the hydrotreating unit 7, the biofuel undergoes a hydrorefining reaction under the action of hydrogen and a catalyst, effectively removing impurities such as oxygen, nitrogen, and sulfur, significantly improving its calorific value, stability, and overall quality, ultimately producing high-quality biofuel that can be used directly. Figure 2 As shown, the high-quality biofuel produced can be stored in biofuel storage tank 03.

[0028] The coordinated operation of the entire system is managed and intelligently controlled by controller 8. Controller 8 establishes communication connections with hydrothermal liquefaction reactor 1, photovoltaic electric heating device 2, solar molten salt device 3, waste heat recovery device 4, separation device 5, biohydrogen production device 6, and hydrogenation and upgrading device 7, forming the control center of the system. It is responsible for centrally monitoring the operating status of each unit, processing key parameters, and executing optimization instructions, thereby ensuring that the entire conversion process from biomass to high-quality biofuel can operate efficiently, stably, and automatically.

[0029] In one embodiment, the controller 8 described above is used for: During the heating stage of the hydrothermal liquefaction reactor 1, the photovoltaic electric heating device 2 is controlled to heat the hydrothermal liquefaction reactor 1. During the heat preservation stage of the hydrothermal liquefaction reactor 1, the solar molten salt device 3 is controlled to provide heat and maintain the temperature of the hydrothermal liquefaction reactor 1.

[0030] In the application, controller 8 is configured to execute a stepped heating control strategy that precisely matches the heat demand of the biomass hydrothermal liquefaction reaction. Specifically, when the system starts up and enters the heating stage of the hydrothermal liquefaction reactor 1, controller 8 controls the photovoltaic electric heating device 2 as the main heat source to rapidly heat the hydrothermal liquefaction reactor 1. This stage utilizes the electrical energy generated by solar photovoltaic power generation to provide instantaneous high power through the electric heater 24, aiming to quickly allow the reactants to pass through unfavorable temperature ranges and rapidly reach the preset target reaction temperature. For example, the heating rate can be controlled within the range of 5°C / min to 15°C / min, preferably 8°C / min to 12°C / min. This rapid heating method effectively shortens the reaction start-up time and avoids energy loss or adverse side reactions that may occur due to slow heating.

[0031] Once the internal temperature of the hydrothermal liquefaction reactor 1 reaches the target reaction temperature, the system automatically switches to the heat preservation stage. At this time, the controller 8 correspondingly switches the main heat source, controlling the solar molten salt device 3 as the main heat source to maintain a precise and long-term heat preservation temperature for the hydrothermal liquefaction reactor 1. The solar molten salt device 3 stores and transfers heat through the molten salt medium heated by the solar collector 33. The molten salt used can be a nitrate mixture, and its wide operating temperature range perfectly covers the heating requirements of the hydrothermal liquefaction reaction. During this heat preservation stage, the controller 8 precisely controls the temperature fluctuation within the reactor to within ±5°C, preferably within ±3°C, thereby ensuring that the hydrothermal liquefaction reaction continues under optimal and stable temperature conditions.

[0032] This multi-source complementary tiered heating strategy is achieved through the intelligent judgment and automatic execution of controller 8. Photovoltaic electric heating device 2 provides short-term, high-quality heat to meet the instantaneous high-power demand during the rapid heating phase; while solar molten salt device 3 undertakes long-term, stable basic heat load, achieving precise temperature maintenance during the reaction process. The two are seamlessly integrated under the coordinated scheduling of controller 8, achieving a dynamic balance between energy supply and process requirements.

[0033] Intelligent heat source switching and precise temperature control ensure the continuity, stability, and efficiency of the entire hydrothermal liquefaction reaction heating process. This not only effectively improves reaction efficiency and product quality consistency but also maximizes the use of free solar energy, significantly reducing reliance on commercial electricity and fossil fuels, fundamentally supporting the system's goal of reducing operating costs and achieving net-zero carbon emissions throughout its entire lifecycle.

[0034] In one embodiment, the controller 8 is used to perform maximum power point tracking control on the photovoltaic electric heating device 2 in order to maximize the power output of the photovoltaic array 21 in the photovoltaic electric heating device 2.

[0035] Specifically, in terms of maximum power point tracking control of the photovoltaic electric heating device 2, the controller 8 is used for: Monitor the output voltage and current of the photovoltaic array 21 in the photovoltaic electric heating device 2; Based on the output voltage and current, voltage perturbations are periodically applied to the photovoltaic array 21; Based on the direction of change in the output power of the photovoltaic array 21 after the voltage disturbance is applied, the direction of the voltage disturbance is dynamically adjusted so as to lock the operating point of the photovoltaic array 21 at the maximum power point.

[0036] In the application, controller 8 employs maximum power point tracking (MPPT) control logic based on perturbation observation to perform intelligent power optimization. Specifically, controller 8 first monitors the output voltage and current of the photovoltaic array 21 in the photovoltaic electric heating device 2 in real time through its built-in monitoring unit to obtain the real-time operating status of the photovoltaic power generation system. Based on the monitored output voltage and current parameters, controller 8 periodically applies a small perturbation to the output voltage of the photovoltaic array 21 and continuously monitors the change in output power of the photovoltaic array 21 after the voltage perturbation. Controller 8 dynamically adjusts the direction of the voltage perturbation according to the direction of output power change: if an increase in output power is detected, the perturbation continues to be applied in the same direction; if a decrease in output power is detected, the perturbation is immediately applied in the opposite direction. Through this continuous feedback loop and iterative optimization mechanism, controller 8 can quickly and accurately lock the operating point of the photovoltaic array 21 at the maximum power point and maintain its stable operation in this optimal state.

[0037] This maximum power point tracking (MPPT) control strategy based on perturbation observation effectively addresses the instability of photovoltaic power generation caused by environmental factors such as changes in light intensity and temperature fluctuations. By implementing MPPT control, the controller 8 can significantly improve the power generation efficiency of the photovoltaic electric heating device 2. This provides a more stable power input guarantee for the rapid heating stage of the hydrothermal liquefaction reactor 1 and improves the overall system's utilization efficiency of solar energy, a free energy source.

[0038] See Figure 2 The photovoltaic electric heating device 2 specifically includes: Photovoltaic array 21 is used to convert solar energy into electrical energy; Energy storage unit 22 is used to store electrical energy generated by photovoltaic array 21; Inverter 23 is used to convert electrical energy from direct current to alternating current; Electric heater 24 is used to heat hydrothermal liquefaction reactor 1 using alternating current converted by inverter 23; Among them, the photovoltaic array 21, energy storage unit 22, inverter 23 and electric heater 24 are all communicatively connected to the controller 8.

[0039] In this application, the photovoltaic array 21 directly converts the received solar radiation energy into direct current (DC) electricity. The energy storage unit 22 (battery) stores excess electrical energy generated by the photovoltaic array 21 when sunlight is abundant and releases it during periods of insufficient sunlight or peak system power demand. This mitigates fluctuations in process heating caused by the intermittent nature of photovoltaic power generation, ensuring the continuity of power supply to the electric heater 24. The inverter 23 converts the DC power output from the energy storage unit 22 or directly generated by the photovoltaic array 21 into alternating current (AC) to meet the AC power input requirements of the subsequent electric heater 24. The electric heater 24, as the final actuator, has its heating element in close contact with the heating wall or internal coils of the hydrothermal liquefaction reactor 1, efficiently converting electrical energy into heat energy to directly heat the materials within the reactor. For example, the energy storage unit 22 can also power the controller 8.

[0040] When the hydrothermal liquefaction reactor 1 is started and enters the heating stage, the controller 8 prioritizes the photovoltaic electric heating device 2 as the main heat source. To maximize the utilization efficiency of photovoltaic power generation, the controller 8 continuously monitors the output voltage and current of the photovoltaic array 21 and executes the maximum power point tracking (MPPT) control algorithm. By periodically applying small voltage disturbances to the photovoltaic array and observing the direction of output power change, the controller dynamically adjusts the operating point to stably operate the photovoltaic array 21 at its maximum power output state. The controller 8 also integrates energy management strategies, real-time meteorological data (such as the typical effective power generation period determined by the local solar radiation time normal distribution, usually about 8 hours per day) and reactor heating requirements to intelligently decide on the allocation and use of electricity: prioritizing the use of the immediate power generation of the photovoltaic array 21, with the insufficient part supplemented by the energy storage unit 22; when photovoltaic power generation is excessive, the excess electricity is stored for backup. Specifically, in terms of energy supply control during the heating process, the controller 8 implements a dual-position control strategy based on reaction temperature feedback: when the internal temperature of the hydrothermal liquefaction reactor 1 is detected to be lower than the preset temperature (e.g., 300°C), the controller determines that it is in a heating demand stage and instructs the energy storage unit 22 to supply power to the electric heater 24 through the inverter 23; when the temperature reaches and stabilizes at the preset temperature (e.g., 300°C), it stops drawing power from the energy storage unit and instead relies mainly on photovoltaic instantaneous power generation or enters the next heating stage. Simultaneously, the controller 8, based on a preset heating curve (e.g., heating rate controlled between 8°C / min and 12°C / min), precisely controls the heating process of the hydrothermal liquefaction reactor 1 by adjusting the power supplied to the electric heater 24 until it reaches the target reaction temperature. All operating parameters of the photovoltaic electric heating device 2, including photovoltaic power generation, energy storage unit state of charge, and electric heater operating status, are monitored and recorded in real time by the controller 8 and integrated into the overall system's coordinated scheduling to ensure rapid, efficient, and stable completion of the reactor's heating task.

[0041] In one embodiment, controller 8 is used for: Acquire system operating parameters; system operating parameters include meteorological data, hydrothermal liquefaction reaction temperature curves, and material heat capacity; The system operating parameters are input into a pre-trained prediction model to obtain prediction results of energy supply and demand trends within a preset future time period; Based on the prediction results, determine the output power allocation strategy; The operating status of the photovoltaic electric heating device 2, the solar molten salt device 3, and the waste heat recovery device 4 are adjusted according to the output power distribution strategy.

[0042] In the application, controller 8 is also configured to execute model-based predictive intelligent energy management strategies to achieve forward-looking and coordinated control of the entire multi-source heating system. Controller 8 first acquires system operating parameters in real time, including local meteorological data affecting energy supply (such as solar radiation intensity and ambient temperature), hydrothermal liquefaction reaction temperature curves reflecting the demands of the reaction process, and material heat capacity determining the heat absorption characteristics of biomass feedstock. These parameters collectively constitute the foundational data for system energy balance analysis and prediction.

[0043] After acquiring the parameters, controller 8 inputs the system operating parameters into a pre-trained prediction model. This prediction model is built upon a multi-source heating simulation model of the hydrothermal reaction system constructed using an instantaneous system simulation platform (such as TRNSYS). Its construction process is based on a set of hydrothermal reaction energy production and consumption data established from historical operating data, and trained using system identification methods such as neural networks or transfer function models. This prediction model can simulate and predict the energy supply capacity and dynamic response characteristics of the photovoltaic electric heating device 2, the solar molten salt device 3, and the waste heat recovery device 4 under different operating conditions, thereby obtaining accurate prediction results of the system's heat load demand and energy supply and demand trends within a preset future time period.

[0044] Based on this prediction, controller 8 can anticipate the system's energy supply and demand, and thus determine the optimal output power allocation strategy. The core of this strategy lies in dynamically allocating the energy supply ratios of photovoltaic electricity, molten salt heat, and recovered waste heat, achieving synergistic optimization of multiple energy sources. Subsequently, controller 8 adjusts in real-time the power output of photovoltaic electric heating device 2, the heat output of solar molten salt device 3, and the heat recovery efficiency of waste heat recovery device 4, according to the established output power allocation strategy.

[0045] This model-based predictive intelligent control method enables the system to proactively address the conflict between the intermittent nature of solar energy resources and the continuous requirements of the process. Through intelligent prediction and closed-loop control, the proportion of solar energy supply can be increased to over 95%, achieving synergistic optimization of multiple energy sources. This not only significantly reduces dependence on traditional fossil fuels but also effectively ensures the heating stability and temperature control accuracy of the hydrothermal liquefaction reactor 1 at each stage. Furthermore, by maximizing the utilization of free solar energy, it further reduces system operating costs.

[0046] The predictive model is structured as a coupled system simulation model based on physical mechanisms and a data-driven parameter correction model. The system simulation model is built using an instantaneous system simulation platform (such as TRNSYS) and fully embeds the thermodynamic and mass transfer equations of core units including the hydrothermal liquefaction reactor 1, photovoltaic electric heating device 2, solar molten salt device 3, and waste heat recovery device 4. It can simulate the dynamic response and energy flow of the system under different meteorological inputs and operational settings. The data-driven model is constructed using time series analysis and machine learning algorithms (such as Long Short-Term Memory networks, LSTM) to learn and predict nonlinear relationships and uncertainties. The predictive model is trained on a historical operational dataset, which includes long-term field meteorological data (solar radiation intensity, ambient temperature), corresponding system operating parameters (such as power, temperature, and flow rate of each device), and the final hydrothermal reaction efficiency indicators. During training, a large amount of simulated data covering various operating conditions is first generated using a system simulation model. This data, along with historical actual operating data, is then input into the data-driven model for joint training. The backpropagation algorithm continuously adjusts the model's internal weights until the predicted trends of system heat load demand, photovoltaic power generation, and molten salt thermal storage capacity within a preset future time period (e.g., the next 24 hours) converge to an acceptable range (e.g., average absolute percentage error less than 5%). The trained model is then integrated into controller 8, which can perform multi-step predictions based on real-time acquired system operating parameters and solve the optimal control problem based on the prediction results, thereby generating a forward-looking output power allocation strategy.

[0047] In one embodiment, in adjusting the operating state of the solar molten salt device 3 according to the output power distribution strategy, the controller 8 is specifically used for: Monitor the temperature and circulation flow rate of the molten salt in solar molten salt device 3; Based on the output strategy of the solar molten salt device in the output power distribution strategy, the control targets for temperature and circulation flow rate are determined; According to the control objectives, the valve opening degree of the molten salt circulation pipeline and / or the speed of the circulation pump in the solar molten salt device 3 are dynamically adjusted.

[0048] In the application, the controller 8 first monitors the temperature and circulation flow of the molten salt in the solar molten salt device 3 in real time through its integrated monitoring unit. These key parameters directly reflect the real-time status and heating capacity of the thermal storage system and are the basic data source for achieving precise control of the outlet temperature of the thermal storage system.

[0049] After acquiring this real-time monitoring data, the controller 8, based on the output strategy specifically designed for the solar molten salt device 3 in the output power distribution strategy, transforms these macroscopic energy distribution instructions into specific, executable control targets for molten salt temperature and circulation flow rate. The determination of these control targets comprehensively considers the heat demand of the hydrothermal liquefaction reactor 1 during the heat preservation stage, the thermal inertia characteristics of the molten salt thermal storage system, and the predicted solar energy input, aiming to achieve an optimal balance between heating stability and energy efficiency.

[0050] To achieve these precise control objectives, controller 8 dynamically adjusts the actuators of the molten salt circulation pipeline in the solar molten salt device 3. Specifically, controller 8 adjusts the opening degree of the valves on the molten salt circulation pipeline and / or adjusts the rotation speed of the circulation pump that drives the molten salt flow by outputting control signals. Adjusting the valve opening degree changes the flow cross-section of the molten salt, while adjusting the rotation speed of the circulation pump changes the flow rate of the molten salt. These two methods, individually or in combination, achieve precise control over the heat transfer of the molten salt.

[0051] This closed-loop control method based on real-time monitoring and target tracking enables the solar molten salt device 3 to serve as a stable and reliable heat source, providing continuous and precise heat input during the heat preservation stage of the hydrothermal liquefaction reactor 1. This control strategy can control reaction temperature fluctuations within a small range of ±5°C or ±3°C, significantly improving the stability and product consistency of the hydrothermal liquefaction reaction. Simultaneously, by optimizing the adjustment of molten salt temperature and flow rate, unnecessary heat loss is avoided, improving the overall utilization efficiency of solar thermal energy.

[0052] See Figure 2 The solar-powered molten salt device 3 specifically includes: The heating circulation pipeline is provided with a molten salt storage tank 31, a first temperature detector 32, a solar collector 33, a second temperature detector 34, a heat preservation device 35, a molten salt circulation pump 36, and a molten salt electric valve 37 in sequence along the direction of molten salt flow. The heat dissipation pipes are connected in parallel to both ends of the molten salt electric valve 37, and an emergency radiator 38 and a heat dissipation electric valve 39 are sequentially installed along the molten salt flow direction. Among them, the first temperature detector 32, the second temperature detector 34, the molten salt circulation pump 36, the molten salt electric valve 37, the emergency radiator 38, and the heat dissipation electric valve 39 are all connected to the controller 8 in communication.

[0053] In the application, the first temperature detector 32 is used to detect the molten salt temperature at the inlet of the solar collector 33, and the second temperature detector 34 is used to detect the molten salt temperature at its outlet. Both provide the controller 8 with real-time temperature rise data of the molten salt flowing through the solar collector 33, which serves as the basis for evaluating the collector's working efficiency and calculating the heat transfer power. Based on this, the controller 8 can implement a two-position control strategy: when the temperature difference between the inlet and outlet of the molten salt exceeds a first preset temperature value (e.g., 10°C), it is determined that the heat collection conditions are good, and the heat collection function is maintained or activated; when the temperature difference is lower than a second preset temperature value (e.g., 2°C), it is determined that the heat collection efficiency is insufficient, and a signal can be issued to stop the active heat collection cycle to save energy. The molten salt storage tank 31 is used to store the molten salt as a heat storage medium and has a heat preservation function to reduce heat loss. The solar collector 33, as the core heating unit, converts the captured solar radiation energy into the sensible heat of the molten salt, but its heating capacity is significantly affected by meteorological conditions such as solar radiation intensity, and is intermittent and uncertain. To this end, the system uses a transient simulation model built based on TRNSYS software to perform flexible and accurate simulation analysis of the multi-source heating system, including the solar collector, to assist in the rational configuration of system parameters and performance evaluation, and to provide support for the predictive model of controller 8. The insulation device 35 is wrapped around the hydrothermal liquefaction reactor 1 to provide heating and insulation. The molten salt circulation pump 36 provides power for the circulation of molten salt in the pipeline; its speed can be adjusted to directly control the flow rate and heat transfer rate of the molten salt. The molten salt electric valve 37 is used to control the flow of molten salt to the hydrothermal liquefaction reactor 1. The parallel-connected heat dissipation pipeline and its emergency radiator 38 and heat dissipation electric valve 39 together form a safe heat dissipation circuit, through which the molten salt can be cooled when emergency cooling is required or maintenance is needed.

[0054] The controller 8 accurately monitors the temperature of the molten salt by receiving the first temperature signal from the first temperature detector 32 and the second temperature signal from the second temperature detector 34 in real time. Based on the pre-set reactor insulation temperature requirements, real-time meteorological data, and the output power allocation strategy given by the prediction model, the controller 8 calculates the required molten salt temperature control target and circulation flow target. To achieve these targets, the controller 8 dynamically adjusts the speed of the molten salt circulation pump 36 to change the molten salt flow rate, and can also fine-tune the opening of the molten salt electric valve 37 to coordinate with the flow rate adjustment, thereby accurately controlling the heat delivered to the hydrothermal liquefaction reactor 1 and ensuring that its internal temperature is stably maintained within the set range (e.g., within ±3°C) during the insulation phase.

[0055] In addition, controller 8 continuously monitors whether the molten salt temperature exceeds the safety limit. Once an overheating risk is detected or a shutdown command is received, controller 8 will immediately close the molten salt electric valve 37 to cut off the main heating circuit, and simultaneously open the heat dissipation electric valve 39 to guide the high-temperature molten salt through the emergency radiator 38 for forced cooling, thereby ensuring the safety of the system equipment. All operating data of this device is integrated into the controller's energy management model, enabling it to work in conjunction with subsystems such as photovoltaic electric heating and waste heat recovery to jointly meet the efficient, stable, and safe heating needs of the hydrothermal liquefaction reactor.

[0056] In one embodiment, in adjusting the operating state of the waste heat recovery device 4 according to the output power distribution strategy, the controller 8 is specifically used for: Obtain product operating parameters used to characterize the type, temperature, and flow rate of the reaction products; Based on the pre-stored operating condition parameter mapping table, query the expected waste heat recovery value corresponding to the product operating condition parameters; Obtain the actual waste heat recovery value of the waste heat recovery device; Based on the expected and actual waste heat recovery values, the speed of the heat exchange medium circulation pump and / or the opening of the flow control valve in the waste heat recovery device 4 are dynamically adjusted.

[0057] In applications, when it is necessary to adjust the operating status of the waste heat recovery device 4 according to the output power distribution strategy, the controller 8 adopts a feedback-in-the-loop control method based on a pre-stored operating condition parameter mapping table to achieve precise quantitative management and closed-loop control of waste heat recovery energy. Specifically, the controller 8 first acquires product operating condition parameters, which characterize the type, temperature, and flow rate of the reaction products, through integrated sensors. These parameters directly reflect the actual state of the high-temperature material produced from the hydrothermal liquefaction reactor 1, providing an accurate data basis for the quantitative management of waste heat recovery.

[0058] Based on a pre-stored operating condition parameter mapping table, controller 8 queries the expected waste heat recovery value corresponding to the current product operating condition parameters. This mapping table defines the expected waste heat recovery energy value corresponding to different combinations of reaction product temperature and flow rate, and is a standardized reference pre-established through historical operating data. At the same time, controller 8 can obtain the actual waste heat recovery value of waste heat recovery device 4 through the heat metering device, ensuring the accuracy and real-time nature of the monitoring results.

[0059] Based on the deviation between the expected and actual waste heat recovery values, controller 8 dynamically adjusts the speed of the heat exchange medium circulation pump and / or the opening of the flow control valve in the waste heat recovery device 4 using a built-in PID controller. This closed-loop control mechanism enables the system to automatically adjust the heat exchange intensity according to real-time operating conditions, increasing the heat exchange medium flow rate to enhance recovery efficiency when the actual recovery value is lower than expected.

[0060] This map-based feedback-in-the-loop control method enables precise monitoring and closed-loop management of waste heat recovery in the hydrothermal liquefaction process, allowing the system to adapt to changes in product operating conditions. Through intelligent mapping and dynamic adjustment, waste heat recovery efficiency can be increased to 15% to 30% of the total process thermal energy, effectively reducing the system's external energy demand.

[0061] In one embodiment, the waste heat recovery device 4 is connected to the biohydrogen production device via a heat exchange pipeline to utilize waste heat to preheat the culture medium of the biohydrogen production device and / or maintain the reaction temperature.

[0062] In the application, the waste heat recovery device 4 can be physically connected to the bio-hydrogen production device 6 through a dedicated heat exchange pipeline, constructing a key path for the cascade utilization of thermal energy within the system. This connection method allows the heat recovered by passing the high-temperature product material (250°C to 320°C) into the waste heat recovery heat exchanger after the hydrothermal liquefaction reaction is completed to be effectively transferred to the bio-hydrogen production device 6, realizing the cascade utilization of heat within the system.

[0063] Specifically, the recovered waste heat can be used in two key areas: first, it is preferentially used to preheat the culture medium in the photosynthetic hydrogen production unit, raising the temperature to a range suitable for microbial growth; second, it is used to maintain the reaction temperature required for photosynthetic bacterial fermentation, especially providing stable heat compensation when the ambient temperature is low, ensuring that the reaction temperature is maintained within the range of 28°C to 35°C, preferably 30°C. This targeted utilization of heat significantly reduces the bio-hydrogen production device 6's own demand for external heating energy, achieving optimized energy circulation within the system.

[0064] By providing a stable heat source for the biohydrogen production process, the growth and metabolism of photosynthetic bacteria are ensured within the optimal temperature range, thereby maintaining a high hydrogen yield. More importantly, this cross-unit waste heat integration strengthens the closed-loop characteristics of the system's materials and energy, transforming the waste heat from the byproducts of the hydrothermal liquefaction stage into a resource heat source for the hydrogen production stage. This further reduces the system's carbon footprint and operating costs, providing support for achieving the goal of "net-zero carbon emissions" and demonstrating significant advantages in the circular economy.

[0065] In one embodiment, the waste heat recovery device 4 can also be used to preheat the biomass feedstock delivered to the hydrothermal liquefaction reactor 1.

[0066] See Figure 2The raw material storage tank 01, the material input pump 02, and the corresponding conveying pipelines constitute the raw material supply path. In application, the biomass raw material from the raw material storage tank 01, after being pumped out by the material input pump 02, does not directly enter the hydrothermal liquefaction reactor 1, but is first introduced into a specially designed raw material preheating channel in the waste heat recovery device 4. This channel is arranged adjacent to the main heat exchange channel for recovering waste heat from the reaction products, and efficient heat exchange is achieved through a partition wall. When the high-temperature reaction products release sensible heat as they flow through the main heat exchange channel, their heat is captured and transferred by the heat exchange medium, and then used to heat the low-temperature biomass raw material flowing through the adjacent preheating channel. Through this process, the temperature of the raw material is significantly increased before entering the hydrothermal liquefaction reactor 1. The controller 8 monitors the temperature at the outlet of the raw material preheating channel and adjusts the conveying rate of the material input pump 02, and performs linkage control with the overall heat recovery strategy of the waste heat recovery device 4 to ensure that while maximizing the recovery of waste heat, a preheated raw material with a suitable temperature is provided to the hydrothermal liquefaction reactor 1.

[0067] See Figure 2 In one embodiment, the separation device 5 includes a three-phase separator 51 and a distillation column 52.

[0068] In this application, the inlet of the three-phase separator 51 is connected to the outlet of the waste heat recovery device 4, and is used to receive the reaction product mixture after being cooled by waste heat recovery. Its function is based on the density difference between the oil, water, and gas phases, using gravity sedimentation and mechanical separation to initially separate the mixture into a crude bio-oil layer in the upper layer, organic wastewater in the middle layer, and a small amount of non-condensable gas that may be generated. The separated organic wastewater is transported to the subsequent bio-hydrogen production unit 6 through its wastewater outlet, while the crude bio-oil is discharged from its crude oil outlet. The inlet of the distillation column 52 is connected to the crude oil outlet of the three-phase separator 51, and is used to receive the crude bio-oil. Its function is to remove residual light components such as water and some low-boiling-point organic matter from the crude bio-oil through distillation, utilizing the different volatility of the components in the mixture, by performing multiple partial vaporizations and partial condensations within the column, thereby obtaining refined bio-oil with higher purity and calorific value, and providing qualified feedstock for the subsequent hydrotreating process. The refined bio-oil obtained at the bottom of the distillation column 52 is finally transported to the hydrotreating unit 7.

[0069] The controller 8 is connected to the interface monitoring instrument of the three-phase separator 51, the distillation temperature sensor, pressure sensor and feed regulating valve of the distillation column 52, etc. By monitoring the operating parameters of the separation and distillation process in real time, the feed rate, column bottom heating power or reflux ratio are dynamically adjusted to ensure the stability of separation efficiency and product quality.

[0070] See Figure 2 In one embodiment, the biohydrogen production device 6 includes an anaerobic fermentation reactor 61, a photobioreactor 62, and a gas phase separator 63.

[0071] In this application, the inlet of the anaerobic fermentation reactor 61 is connected to the wastewater outlet of the separation device 5 to receive wastewater rich in organic matter. Within the anaerobic fermentation reactor 61, the wastewater undergoes dark fermentation in an anaerobic environment by a specific anaerobic microbial community. This process decomposes complex organic matter and partially converts it into hydrogen, carbon dioxide, and liquid-phase metabolites, primarily volatile fatty acids. The inlet of the photobioreactor 62 is connected to the liquid-phase outlet of the anaerobic fermentation reactor 61 to receive the fermentation broth containing substrates such as volatile fatty acids. In this reactor, photosynthetic bacteria (such as purple non-sulfur bacteria) utilize the organic acids produced during the dark fermentation stage for photofermentation under light conditions, further converting the substrate into hydrogen and completing the deep degradation of organic matter. The inlet of the gas phase separator 63 is connected to the gas-phase outlets of both the anaerobic fermentation reactor 61 and the photobioreactor 62 to collect and treat the mixed gas (mainly hydrogen, carbon dioxide, and small amounts of other gases) produced in both stages. Its internal components purify hydrogen from the mixed gas through adsorption, membrane separation, or low-temperature distillation units, ultimately obtaining a high-purity hydrogen product, which is then transported from the outlet to the hydrogen inlet of the hydrogenation and upgrading unit 7.

[0072] The controller 8 communicates with the temperature, pH, pressure, and level sensors of each reactor, as well as actuators such as light intensity regulators, feed pumps, and gas flow meters. By coordinating the process parameters (such as organic loading rate, hydraulic retention time, light intensity, and temperature) of the two stages of dark fermentation and light fermentation, it optimizes the efficiency and stability of the entire bio-hydrogen production process and integrates the recovered hydrogen production and purity data into the global management of the system's material and energy balance.

[0073] In one embodiment, the production system further includes a human-machine interface that is communicatively connected to the controller 8. The human-machine interface is used to receive input commands from operators and to display the operating status parameters and alarm information of the hydrothermal liquefaction reactor, photovoltaic electric heating device, solar molten salt device, waste heat recovery device, biohydrogen production device, and hydrogenation and upgrading device.

[0074] See Figure 3 The human-machine interface (HMI), serving as the core platform for operator-system interaction, is developed based on the MCGS platform. The HMI has dual functions: firstly, it receives various commands from operators, including setting key process parameters such as target reaction temperature and reaction time, and switching system operating modes; secondly, it serves as a centralized information display center, displaying real-time operating status parameters of the hydrothermal liquefaction reactor 1, photovoltaic electric heating device 2, solar molten salt device 3, waste heat recovery device 4, biohydrogen production device 6, and hydrogenation and upgrading device 7. These parameters cover key data such as reaction temperature, system pressure, real-time power of each energy source, and energy flow rate. It also promptly displays system status alarm information, ensuring operators can quickly detect and respond to abnormal situations.

[0075] The human-machine interface maintains a communication connection with controller 8 and field actuators, including electric valves, frequency converters, and electric heaters, forming a complete closed-loop control system. This ensures the accurate execution of operating commands and the real-time transmission of status feedback. Through this integrated design, complex distributed system information is effectively integrated into a unified interface, enabling centralized monitoring and dynamic control of the entire multi-source heating complementary heating system and even the entire biofuel production system. Figure 3 As shown, key data, reaction processes, reaction times, and abnormal alarms of the multi-source complementary heating system (electric heating, heat collection and storage, and waste heat) can be displayed on the human-machine interface, enabling real-time monitoring of the multi-source complementary heating system.

[0076] The human-machine interface presents complex processes and equipment status in a visual way, greatly reducing the operational complexity of the system. This allows operators to fully grasp the system's operating status and make quick decisions through a single interface. Simultaneously, centralized alarm management and parameter setting functions not only improve the system's automation level and operational reliability but also support one-click monitoring and intelligent scheduling. This enhances the system's operability and user experience, providing crucial data support and operational assurance for the safe, stable operation and continuous optimization of the entire production system.

[0077] The key process parameters of the system will be further described below.

[0078] Regarding the hydrothermal reaction process, the reaction parameters are as follows: the reaction temperature range is 280°C to 370°C. Within this range, the bio-oil yield is low below 300°C; above 350°C, excessive pyrolysis may lead to an increase in gaseous products. The preferred reaction temperature is 320°C to 340°C, which achieves the optimal balance between efficient biomass conversion and bio-oil yield.

[0079] Reaction pressure: To maintain the reaction system in the liquid phase, the reaction pressure must be the saturated vapor pressure at the corresponding temperature, ranging from 10 MPa to 25 MPa. The most preferred pressure range is 12 MPa to 18 MPa.

[0080] Reaction time: ranging from 15 to 90 minutes. Too short a time results in incomplete conversion, while too long a time increases energy consumption and may trigger side reactions. The optimal reaction time is 30 to 45 minutes.

[0081] Based on the above parameters, this invention designs a stepped heating and insulation mode: a photovoltaic electric heating device 2 is used for rapid heating, with the heating rate controlled within the range of 5°C / min to 15°C / min, preferably 8°C / min to 12°C / min, to quickly pass through the unfavorable intermediate reaction stage. Once the target reaction temperature is reached, the system switches to a solar-powered molten salt device 3 for precise insulation, controlling the reaction temperature fluctuation within ±5°C, preferably within ±3°C. The molten salt is a nitrate mixture with an operating temperature range of 250°C to 550°C, perfectly covering the requirements of the hydrothermal liquefaction reaction.

[0082] Regarding the green hydrogen production system that integrates photosynthetic organisms and wastewater, this part consists of an anaerobic acidification and photosynthetic hydrogen production section. First, functional materials are used to directionally regulate organic acids, primarily propionic acid (30-40%) and acetic acid (50-60%), for the growth of photosynthetic bacteria to produce hydrogen. The wastewater from hydrothermal liquefaction (typically with a COD range of 20,000 mg / L to 80,000 mg / L) is first subjected to anaerobic acidification.

[0083] In the biohydrogen production device 6, the bacterial strains used are photosynthetic bacteria, such as purple non-sulfur bacteria, or a mixture of these bacteria with microalgae. The light intensity ranges from 2000 lux to 8000 lux, with a preference of 5000 lux to 6000 lux. The reaction temperature is maintained between 28°C and 35°C, with a preference of 30°C. The pH of the culture medium is controlled between 6.8 and 7.5, with a preference of 7.0 to 7.2.

[0084] The acidified effluent is introduced into the photosynthetic hydrogen production reactor in biological hydrogen production unit 6, where the organic loading rate is controlled at 2 kg COD / m³. 3 • up to 8kg COD / m 3 ·d, preferably 4kgCOD / m 3 • up to 6 kg COD / m 3 •d. The hydraulic residence time is 2 to 6 days, preferably 3 to 4 days. The generated hydrogen is combined with the hydrogen from the photosynthetic hydrogen production unit and purified to a purity of over 99.5%, which is then used for subsequent hydrogenation purification.

[0085] The volume of the photosynthetic hydrogen production reactor is calculated as follows: (Total COD of wastewater from a single batch in the hydrothermal unit × Hydrogen production rate) / Hydrogen quantity required per batch in the hydrogenation unit. The minimum effective volume of the reactor can be determined by optimizing the organic loading rate and hydraulic retention time.

[0086] In addition, the photosynthetic bacteria cells harvested after the reaction (biomass concentration can reach 2g / L to 5g / L) can be used as nitrogen and phosphorus-rich organic fertilizer after dehydration, with a total nitrogen content >6% and a total phosphorus content >1%.

[0087] Regarding the green hydrorefining system for bio-crude oil, the bio-crude oil obtained from hydrothermal liquefaction is mixed with the aforementioned green hydrogen and refined in hydrorefining unit 7.

[0088] The hydrogen-to-oil volume ratio is 600:1 to 1200:1, preferably 800:1 to 1000:1. The reaction temperature is 300°C to 400°C, preferably 350°C to 380°C. The reaction pressure is 8 MPa to 15 MPa, preferably 10 MPa to 12 MPa. The catalyst used can be a conventional Ni-Mo or Co-Mo based sulfidation catalyst.

[0089] The following section uses food waste (wet waste) as a specific example of biomass raw material to further introduce the net-zero carbon solar-driven high-quality biofuel production system provided by this invention.

[0090] Food waste (wet waste) is processed into bio-oil through hydrothermal liquefaction (HTL), followed by hydrogen production via photosynthesis to provide green hydrogen for further hydrogenation and upgrading, ultimately yielding high-quality biofuel. The system scale is based on a 5L hydrothermal reactor and a processing capacity of 38.8kg of food waste, but scaled up proportionally to 5kg / batch (based on a 5L reactor loading, assuming a food waste density of approximately 1kg / L). The system is designed to process one batch per day, achieving a self-consistent closed-loop operation of energy and materials.

[0091] The hydrothermal liquefaction reactor 1 has a reactor volume of 5L; the amount of wet waste processed is 5kg / batch (70% moisture content, 1.5kg dry matter); the reaction parameters are temperature 330°C (optimal range 320-340°C), pressure 15MPa (optimal range 12-18MPa), and time 40 minutes (optimal range 30-45 minutes).

[0092] Product yield: The liquefaction rate of bio-oil dry matter is 25%, so the bio-oil yield = 1.5kg × 25% = 0.375kg / batch; the yield of high-quality biofuel is 75% (taking the middle value of 70-80%), and the yield = 0.375kg × 75% = 0.281kg / batch.

[0093] The hydrogenation unit 7 requires 3.75g of hydrogen per kg of wet waste. Therefore, 5 kg of wet waste requires 5 × 3.75g = 18.75g of hydrogen (the volume under standard conditions is 18.75g / 2g / mol × 22.4L / mol = 210L). The hydrogenation conditions are as follows: Hydrogen-to-oil volume ratio: 800:1 (optimal range 800-1000:1); reaction temperature: 350°C (optimal range 350-380°C); reaction pressure: 10MPa (optimal range 10-12MPa); catalyst: Ni-Mo sulfidation catalyst.

[0094] The hydrogen production reactor volume and hydrogen yield parameters (30-50 mL / L / h, operating for 8 hours) are as follows: For 5 kg of wet waste, 210 L of hydrogen is required. At the minimum volumetric yield of 50 mL / L / h, each liter of reactor produces 0.4 L of hydrogen per 8 hours, with a volume of 210 L / 0.4 L / L = 525 L. At the maximum volumetric yield of 30 mL / L / h, each liter of reactor produces 0.24 L of hydrogen per 8 hours, with a volume of 210 L / 0.24 L / L = 875 L. Taking the intermediate value, the designed hydrogen production reactor volume is 0.7 m³. 3 (700L).

[0095] Hydrogen production parameters: a mixed flora of purple non-sulfur bacteria and microalgae; light intensity: 5000-10000 lux; temperature: 30°C (optimal range 28-35°C); pH: 7.0-7.2; organic loading rate: 4-6 kg COD / m³ 3 • d (using hydrothermal liquefaction wastewater, COD approximately 50,000 mg / L), hydraulic retention time: 3-4 days; wastewater treatment: hydrothermal liquefaction wastewater production approximately 5L / batch (based on 5kg wet waste), COD load approximately 0.25kg / batch. For 0.7m 3 The reactor needs to process a daily flow rate of 0.233 m³ / h. 3 / d (based on HRT=3 days), therefore the wastewater needs to be stored or diluted before feeding to match the organic load rate.

[0096] Hydrogen production is 0.7m. 3 The reactor's hydrogen production capacity is 700L × (30-50mL / L / h) × 8h = 168-280L / day, with a coverage requirement of 210L. Byproducts: photosynthetic bacteria cell yield of 2-5g / L, which can be dehydrated and used as fertilizer (total nitrogen >6%, total phosphorus >1%).

[0097] This system adopts a tiered photovoltaic-photothermal-waste heat recovery complementary energy supply mode to provide a complete heat source for the hydrothermal liquefaction reactor. The system uses electrical energy as the unified energy metering benchmark to calculate the energy consumption of reactor heating, insulation, material conveying, and auxiliary units.

[0098] During reactor operation, the photovoltaic electric heating device 2 primarily handles the heat load requirements during the rapid heating phase. According to the system design, the peak power during the electric heating phase is 11.4 kW, operating for 6 hours per day, corresponding to a daily energy consumption of 68.4 kWh, to meet the rapid heating requirements of the reactor from room temperature to the reaction temperature range. After the reactor reaches the required temperature for the hydrothermal liquefaction reaction, heat storage and insulation are necessary to maintain this temperature. The power required for the heat storage and insulation phase is 630W, and the energy requirement for the 8-hour insulation phase is 5.04 kWh.

[0099] Under continuous operation, the system also includes various electrically driven and auxiliary equipment, with the following daily energy consumption: a 2.5 kW screw pump with a 120 m head, operating for 3 hours per day, consumes 7.5 kWh; hydraulic cylinders and pumps consume 12.0 kWh; the stirring system consumes 4.8 kWh; the homogenization pretreatment unit consumes 1.6 kWh; the peristaltic pump consumes 0.48 kWh; the magnetic stirrer consumes 0.8 kWh; and the rotary evaporator consumes 1.313 kWh. The above equipment constitutes the direct power demand of the reaction system, with a total energy consumption of 101.933 kWh.

[0100] On the renewable energy supply side, the system is equipped with a solar molten salt thermal storage-collector unit for reactor insulation and heat buffering. The relevant operating energy consumption of the solar molten salt unit 3 includes: 2.72 kWh of daily energy consumption for 8 hours of continuous operation of the molten salt pump and 8.0 kWh of daily energy consumption for driving the solar tracking bracket of the trough collector, totaling 10.72 kWh. The molten salt thermal storage medium is a nitrate mixture, used for heat supply during the reactor insulation phase.

[0101] The system is also equipped with a photovoltaic power generation-storage unit to meet the power demand for continuous operation. The photovoltaic modules are matched to the reactor size, with a total configuration area of ​​approximately 127 m². 2 The system is equipped with an inverter and batteries. The controllers (such as PLC / DCS, industrial computers, sensors, actuators, and control cabinet cooling) operate 24 hours a day, consuming a total of 26.4 kWh / day. Auxiliary power consumption for environmental temperature control, lighting, and small pump loads totals 1.451 kWh / day. The equivalent energy consumption of this system is 148.069 kWh.

[0102] In addition, the system fully recovers the medium-to-high temperature sensible heat (approximately 250–320 °C) flowing out of the hydrothermal liquefaction products, which is used to preheat the photosynthetic hydrogen production medium or for heating the plant area. The waste heat recovery rate is approximately 15–30%, which effectively reduces the system's external energy demand and improves the overall energy utilization efficiency.

[0103] Regarding intelligent control, the predictive model is a multi-source heating simulation model of the hydrothermal reaction system built on TRNSYS. Based on meteorological data, reaction temperature curves, and material heat capacity, the energy supply ratio of photovoltaic power, molten salt heat, and waste heat recovery is dynamically allocated. For monitoring and execution, perturbation observation-based (MPPT) control is used for photovoltaic power generation monitoring to optimize photovoltaic panel output; for waste heat recovery monitoring, map-based feedback-in-the-loop control is used, with a pre-stored operating condition parameter mapping table, and PID control is used to adjust the heat exchange medium flow rate; for human-machine interaction, the MCGS platform is used to centrally display data such as temperature, pressure, and energy flow rate, and to set control parameters.

[0104] Controller 8 dynamically adjusts energy and material distribution to ensure operation under optimal parameters. It processes 5 kg of wet waste daily, producing 0.281 kg of high-quality biofuel and by-product fertilizer, achieving net-zero emissions. This case study demonstrates the integrated design of a 5L hydrothermal reactor with a matching solar heating, photosynthetic hydrogen production, and hydrogen refueling system. The system scale is based on the parameters shown in the diagram, ensuring technical feasibility and energy efficiency optimization.

[0105] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A net-zero carbon solar-powered high-quality biofuel production system, characterized in that, include: A hydrothermal liquefaction reactor is used to receive biomass raw materials for hydrothermal liquefaction reaction to obtain reaction products; A photovoltaic electric heating device is used to heat the hydrothermal liquefaction reactor; A solar-powered molten salt device is used to heat and maintain the temperature of the hydrothermal liquefaction reactor. The waste heat recovery device has its inlet connected to the reaction product outlet of the hydrothermal liquefaction reactor and is used to recover the waste heat of the reaction products. The separation device has an inlet connected to the outlet of the waste heat recovery device, and is used to separate the reaction products after waste heat absorption into bio-crude oil and organic wastewater. The biohydrogen production device has its inlet connected to the wastewater outlet of the separation device, and is used to produce hydrogen from the organic wastewater through fermentation by photosynthetic bacteria. The hydro-upgrading unit has a crude oil inlet connected to the crude oil outlet of the separation unit and a hydrogen inlet connected to the hydrogen outlet of the bio-hydrogen production unit, and is used to hydro-upgrade the bio-crude oil into biofuel. The controller is communicatively connected to the hydrothermal liquefaction reactor, photovoltaic electric heating device, solar molten salt device, waste heat recovery device, separation device, biohydrogen production device, and hydrogenation and upgrading device.

2. The net-zero carbon solar-powered high-quality biofuel production system according to claim 1, characterized in that, The controller is used for: During the heating stage of the hydrothermal liquefaction reactor, the photovoltaic electric heating device is controlled to heat the hydrothermal liquefaction reactor. During the heat preservation stage of the hydrothermal liquefaction reactor, the solar molten salt device is controlled to provide heat and maintain the temperature of the hydrothermal liquefaction reactor.

3. The net-zero carbon solar-powered high-quality biofuel production system according to claim 1, characterized in that, The controller is used to perform maximum power point tracking control on the photovoltaic electric heating device in order to maximize the power output of the photovoltaic array in the photovoltaic electric heating device.

4. The net-zero carbon solar-powered high-quality biofuel production system according to claim 1, characterized in that, The controller is used for: Acquire system operating parameters; the system operating parameters include meteorological data, hydrothermal liquefaction reaction temperature curves, and material heat capacity; The system operating parameters are input into a pre-trained prediction model to obtain prediction results of energy supply and demand trends within a preset future time period; Based on the prediction results, an output power allocation strategy is determined; The operating status of the photovoltaic electric heating device, the solar molten salt device, and the waste heat recovery device are adjusted according to the output power distribution strategy.

5. A net-zero carbon solar-powered high-quality biofuel production system according to claim 4, characterized in that, In adjusting the operating state of the solar molten salt device according to the output power distribution strategy, the controller is specifically used for: Monitor the temperature and circulation flow rate of the molten salt in the solar molten salt device; The control targets for temperature and circulation flow rate are determined based on the output strategy of the solar molten salt device in the output power distribution strategy. According to the control objective, the valve opening degree of the molten salt circulation pipeline and / or the rotation speed of the circulation pump in the solar molten salt device are dynamically adjusted.

6. A net-zero carbon solar-powered high-quality biofuel production system according to claim 4, characterized in that, In adjusting the operating state of the waste heat recovery device according to the output power distribution strategy, the controller is specifically used for: Obtain product operating parameters used to characterize the type, temperature, and flow rate of the reaction products; Based on the pre-stored operating condition parameter mapping table, query the expected waste heat recovery value corresponding to the product operating condition parameters; Obtain the actual waste heat recovery value of the waste heat recovery device; Based on the expected waste heat recovery value and the actual waste heat recovery value, the speed of the heat exchange medium circulation pump and / or the opening of the flow control valve in the waste heat recovery device are dynamically adjusted.

7. A net-zero carbon solar-powered high-quality biofuel production system according to any one of claims 1 to 6, characterized in that, The production system also includes a human-machine interface that is communicatively connected to the controller. The human-machine interface is used to receive input commands from operators and to display the operating status parameters and alarm information of the hydrothermal liquefaction reactor, photovoltaic electric heating device, solar molten salt device, waste heat recovery device, biohydrogen production device, and hydrogenation and upgrading device.

8. A net-zero carbon solar-powered high-quality biofuel production system according to any one of claims 1, characterized in that, The waste heat recovery device is connected to the bio-hydrogen production device via a heat exchange pipeline to utilize the waste heat to preheat the culture medium of the bio-hydrogen production device and / or maintain the reaction temperature.

9. A net-zero carbon solar-driven high-quality biofuel production system according to any one of claims 3, characterized in that, In terms of maximum power point tracking control of the photovoltaic electric heating device, the controller is specifically used for: Monitor the output voltage and current of the photovoltaic array in the photovoltaic electric heating device; Based on the output voltage and current, voltage perturbations are periodically applied to the photovoltaic array; Based on the direction of change in the output power of the photovoltaic array after the voltage disturbance is applied, the direction of the voltage disturbance is dynamically adjusted to lock the operating point of the photovoltaic array at the maximum power point.

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