Biomass depolymerization device and method thereof

Abstract

The invention provides a biomass depolymerization device and method, the biomass depolymerization device comprises: a reaction device with a reaction chamber, the reaction chamber provides an accommodating space for a biomass raw material to be treated and a heat transfer medium, the heat transfer medium is a liquid medium containing liquid metal, and the heat transfer medium is distributed on the surface of the biomass raw material; the electromagnetic wave generating device comprises a microwave generating unit and an electromagnetic induction generating unit, the microwave generating unit is used for emitting microwaves of a first frequency to the reaction cavity, and the electromagnetic induction generating unit is used for emitting an alternating magnetic field of a second frequency to the reaction cavity; and the microwave and the alternating magnetic field cooperate with the heat transfer medium to heat the biomass raw material so as to realize depolymerization of the biomass raw material. According to the biomass depolymerization device provided by the invention, the electromagnetic wave is cooperated with the liquid medium containing the liquid metal to form a heat source to depolymerize the biomass, so that the reaction rate can be effectively improved, the biomass depolymerization is more sufficient, the product selectivity is remarkably improved, and the quality of various types of products is also guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass degradation, and in particular to a biomass depolymerization device and a method thereof. Background Art

[0002] Biomass refers to organic matter formed through photosynthesis. Common plant-based biomass includes agricultural waste (such as straw and rice husks), forestry waste (such as wood chips and branches), and energy crops. Biomass is a renewable resource, and with the growing global demand for sustainable energy and green materials, the efficient utilization of biomass has become a research hotspot.

[0003] Traditional methods for processing biomass to convert it into biomass energy include direct combustion, thermochemical conversion, and biochemical conversion. While direct combustion is technically simple and easy to implement, it suffers from low combustion efficiency, incomplete combustion leading to low energy utilization, and pollutant emissions. Thermochemical conversion, including pyrolysis, gasification, and liquefaction, can convert biomass into biochar, bio-oil, and syngas, but suffers from high reaction temperatures, high energy consumption, and poor product selectivity. Furthermore, bio-oil contains a large amount of oxygenated compounds, resulting in low quality. The gasification process easily produces byproducts such as tar, making subsequent purification difficult. Liquefaction technology has high equipment requirements and catalyst recovery challenges. Biochemical conversion, including fermentation and enzymatic hydrolysis, has the advantages of mild reaction conditions, but is slow, has a long cycle, and requires stringent pretreatment of the biomass feedstock, resulting in high costs.

[0004] With technological advancements, microwave heating technology has been widely used in the food, industrial, and agricultural sectors, such as heating food and sterilizing in daily life. Microwave heating can also be used in biomass processing to achieve biomass energy conversion. For example, existing technologies first subject biomass feedstock to conventional pyrolysis, then subject the resulting solid material to microwave pyrolysis to produce biochar. While this method can improve product conversion efficiency to a certain extent, due to its integration with traditional pyrolysis methods, it still retains the drawbacks of traditional pyrolysis methods. Furthermore, it suffers from uneven heating, low efficiency, and poor quality of products other than biochar, leaving room for improvement. Summary of the Invention

[0005] The present invention provides a biomass depolymerization device and method thereof, which are used to solve the defects of traditional biomass treatment methods in the prior art, such as environmental pollution, high energy consumption, poor product selectivity, low product quality, and high cost. Although combining traditional pyrolysis with microwave pyrolysis to treat biomass can improve the conversion efficiency of certain specific products, it still has the disadvantages of traditional pyrolysis, as well as problems such as uneven heating, low efficiency and poor quality of other types of products. The present invention provides a new idea, which can comprehensively improve the biomass depolymerization reaction rate, improve the quality of various types of products while promoting sufficient reaction of biomass, reduce energy consumption, and reduce the generation of pollutants, thereby benefiting environmental protection.

[0006] The present invention provides a biomass depolymerization device, comprising: a reaction device having a reaction chamber, wherein the reaction chamber provides a space for accommodating a biomass raw material to be processed and a heat transfer medium, wherein the heat transfer medium is a liquid medium containing liquid metal, and the heat transfer medium is distributed on the surface of the biomass raw material; The electromagnetic wave generating device includes a microwave generating unit and an electromagnetic induction generating unit. The microwave generating unit is used to emit microwaves of a first frequency to the reaction chamber, and the electromagnetic induction generating unit is used to emit an alternating magnetic field of a second frequency to the reaction chamber. The microwaves and the alternating magnetic field cooperate with the heat transfer medium to heat the biomass raw material to achieve depolymerization of the biomass raw material.

[0007] According to a biomass depolymerization device provided by the present invention, the microwave generating unit is embedded in the cavity wall of the reaction cavity, so that the microwaves generated by the microwave generating unit directly act on the biomass raw material and the heat transfer medium; or, the reaction device is built into the microwave generating unit, so that the microwaves generated by the microwave generating unit penetrate the reaction device and then act on the biomass raw material and the heat transfer medium.

[0008] According to a biomass depolymerization device provided by the present invention, the coil of the electromagnetic induction generating unit is evenly wound on the outer wall of the reaction device.

[0009] According to a biomass depolymerization device provided by the present invention, the reaction device is built into the microwave generating unit, and a hot air component is provided on the upper part of the microwave generating unit. The hot air component includes a hot air fan and a heating pipe. The air heated by the heating pipe is blown toward the reaction device under the action of the hot fan.

[0010] According to a biomass depolymerization device provided by the present invention, the hot air component also includes a reflective cover, which is fixed to the inner top wall of the microwave generating unit. The hot air fan and the heating tube are sequentially arranged below the reflective cover, and the reflective cover is used to radiate the heat of the heating tube to the reaction device.

[0011] According to a biomass depolymerization device provided by the present invention, the first frequency is between 300 MHz and 300 GHz, and the second frequency is between 50 kHz and 300 kHz.

[0012] According to a biomass depolymerization device provided by the present invention, the heat transfer medium is one of liquid metal, a liquid metal-ionic liquid mixture and a liquid metal-inorganic material composite.

[0013] According to a biomass depolymerization device provided by the present invention, the reaction device is provided with a temperature sensor and a pressure sensor for respectively monitoring the temperature and pressure in the reaction chamber.

[0014] According to the present invention, a biomass depolymerization device further includes: a product collection device connected downstream of the reaction device, used to separate and collect the gaseous products, liquid products and solid products after the depolymerization of the biomass raw material; and / or a pretreatment device, used to crush, and / or dry, and / or remove impurities from the biomass raw material to be treated.

[0015] The present invention also provides a biomass depolymerization method, which is applied to the above biomass depolymerization device and comprises the following steps: Mixing a biomass raw material to be processed with a heat transfer medium to obtain a reaction mixture, wherein the heat transfer medium is a liquid medium containing liquid metal; Microwaves of a first frequency and an alternating magnetic field of a second frequency are emitted to the reaction mixture, and the microwaves and the alternating magnetic field cooperate with the heat transfer medium to heat the biomass raw material to achieve depolymerization of the biomass raw material.

[0016] The biomass depolymerization device and method provided by the present invention use electromagnetic waves in conjunction with a liquid medium containing liquid metal to form a heat source for depolymerizing biomass. It can quickly and deeply depolymerize the complex macromolecular structure of biomass. Compared with traditional biomass treatment methods, it improves the reaction rate and shortens the reaction time, while making biomass depolymerization more complete, significantly improving product selectivity, and ensuring the quality of various types of products. By utilizing the efficient heating characteristics of electromagnetic waves and the good thermal conductivity of liquid metal, the high heat demand in traditional thermochemical treatment is reduced, and compared with traditional pyrolysis technology, energy consumption can be effectively reduced; the reaction process reduces the generation of pollutants in traditional biomass treatment processes, such as a significant reduction in the amount of tar generated during pyrolysis, while achieving the full utilization of biomass components, which is in line with the concepts of sustainable development and green chemistry. The heat transfer medium only serves as a medium and catalyst during the reaction process. After the reaction is completed, it can be recovered and reused through simple separation means, reducing production costs and reducing resource waste.

[0017] The present invention can be used to process various types of biomass raw materials, including different types of agricultural waste, forestry waste, and energy crops, and has relatively loose requirements on the quality and form of the raw materials, thereby broadening the scope of biomass resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is one of the structural schematic diagrams of the biomass depolymerization device provided by the present invention.

[0020] Figure 2 This is the second structural schematic diagram of the biomass depolymerization device provided by the present invention.

[0021] Figure 3 This is the third structural schematic diagram of the biomass depolymerization device provided by the present invention.

[0022] Figure 4 This is the fourth structural schematic diagram of the biomass depolymerization device provided by the present invention.

[0023] Figure 5 It is a schematic flow chart of the biomass depolymerization method provided by the present invention.

[0024] Reference numerals: 10. Reaction device; 11. Microwave generating unit; 12. Electromagnetic induction generating unit; 121. Coil; 13. Hot fan; 14. Heating tube; 15. Temperature sensor; 16. Pressure sensor; 17. Product collecting device; 171. Condensing device; 172. Filtering device; 173. Distillation device; 174. Centrifugal separation device. DETAILED DESCRIPTION

[0025] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0026] like Figures 1 to 4As shown, the present invention provides a biomass depolymerization device, comprising: a reaction device 10 having a reaction chamber, the reaction chamber providing a storage space for a biomass raw material to be processed and a heat transfer medium, the heat transfer medium being a liquid medium containing liquid metal, and the heat transfer medium being distributed on the surface of the biomass raw material; an electromagnetic wave generating device, comprising a microwave generating unit 11 and an electromagnetic induction generating unit 12, the microwave generating unit 11 being used to emit microwaves of a first frequency into the reaction chamber, the electromagnetic induction generating unit 12 being used to emit an alternating magnetic field of a second frequency into the reaction chamber, the microwaves and the alternating magnetic field cooperating with the heat transfer medium to heat the biomass raw material to achieve depolymerization of the biomass raw material.

[0027] The heat transfer medium is a liquid medium containing liquid metal. When the electromagnetic wave generating device is in operation, the microwaves emitted by the microwave generating unit 11 can directly act on the biomass raw material, causing the polar molecules in the biomass to vibrate rapidly in the microwave alternating electric field, generating frictional heat, thereby achieving rapid and uniform heating of the biomass. Different components in the biomass, such as lignin and cellulose, have different microwave absorption capacities, which can specifically promote the decomposition of specific components. At the same time, the free electrons in the liquid metal move violently under the action of microwaves and collide with each other to provide heat that acts on the biomass, further promoting the depolymerization reaction of the biomass. The microwaves can also excite the liquid metal to generate local high-temperature plasma, destroying the chemical bonds of cellulose, hemicellulose, and lignin in the biomass, making the depolymerization reaction of the biomass more complete. The alternating magnetic field emitted by the electromagnetic induction generating unit 12 can cause the liquid metal to generate eddy currents and rapidly heat up. This heat heats the biomass through heat conduction and heat radiation, which is beneficial to improving heating uniformity and further promoting the depolymerization reaction of the biomass. Specifically, the alternating magnetic field generated by the electromagnetic induction generating unit 12 directly heats the liquid metal to a high temperature through the eddy current effect. The liquid metal, as a heat transfer medium, can transfer heat to the biomass raw material through heat conduction, convection or radiation, thereby causing the biomass to undergo a depolymerization reaction. Liquid metal has fast heat transfer and can reduce heat loss. In addition, the convection characteristics of liquid metal can avoid local overheating, making the biomass heated more evenly and improving the reaction efficiency. The heat transfer medium of the present invention can stably maintain a liquid state at the reaction temperature, and by adjusting the electromagnetic induction parameters and the type and content of the metal in the heat transfer medium, it is possible to achieve precise control of the biomass heating process.

[0028] Since the use of microwave heating technology alone has the problem of uneven heating or difficulty in deeply depolymerizing the complex macromolecular structure of biomass, and the use of electromagnetic induction heating technology alone has the problem of poor synergistic depolymerization effect on cellulose, hemicellulose and lignin in biomass, it is impossible to fully release the effective components in biomass, which limits the high-value utilization of biomass. Therefore, the present invention combines the two heating technologies and cooperates with liquid metal to further improve the heating temperature and heat conduction / radiation uniformity, thereby comprehensively improving the depolymerization effect of biomass. Through a mixed system of biomass raw materials and liquid metals in a specific mass ratio, and a reaction device with good electromagnetic wave penetrability, high temperature resistance and corrosion resistance, the effective transmission of electromagnetic wave energy and the smooth progress of the reaction are guaranteed, while ensuring the stability of the liquid metal during the reaction process.

[0029] To ensure more uniform heat conduction, a liquid medium is used to fully contact the biomass raw material. For example, the biomass raw material is completely immersed in the liquid medium, or at least the liquid medium is evenly attached to the surface of the biomass raw material to form a wrapping effect, so that the liquid medium can evenly transfer heat to the biomass raw material during the subsequent reaction process, ensuring that all biomass raw materials are fully depolymerized. To ensure a uniform heating effect, the biomass raw material and the heat transfer medium are fully mixed before the reaction. The mixing operation can be performed before loading into the reaction device 10, or after loading into the reaction device 10, to ensure that the biomass raw material and the heat transfer medium are fully mixed when the electromagnetic wave generating device is operating.

[0030] In an optional embodiment of the present invention, the reaction device 10 is used as both a reaction container and a mixing container, and the biomass raw material and the heat transfer medium can be directly added to the reaction device 10 for sufficient mixing before starting the reaction.

[0031] In other optional embodiments of the present invention, the biomass depolymerization device further includes a mixing device, wherein the biomass raw material and the heat transfer medium are first placed in the mixing device and mixed evenly before being poured into the reaction device 10 for reaction. Preferably, the mixing device is equipped with a stirrer, such as a stirring paddle, which stirs the mixture at an appropriate speed to achieve sufficient mixing.

[0032] In order to improve the flexibility of microwave heating, the present invention can flexibly arrange the microwave generating unit 11 and the reaction device 10 to provide diverse structural configurations and heating effects.

[0033] In one embodiment, Figure 1As shown, the microwave generating unit 11 is embedded in the cavity wall of the reaction cavity, so that the microwaves generated by the microwave generating unit 11 directly act on the biomass raw material and the heat transfer medium. This embodiment can greatly shorten the microwave propagation distance, make the microwaves act evenly on the biomass raw material and the heat transfer medium from all directions, improve the heating efficiency, and help the biomass raw material to quickly heat up and reach a higher temperature. The reaction device 10 is similar to the principle of a "microwave oven", directly heating the material in the reaction cavity, which can promote the full depolymerization of the biomass raw material. Integrating the microwave generating unit 11 into the reaction device 10 can reduce the number of structural parts, promote the compactness of the structural arrangement, and help to achieve the miniaturization of the overall biomass depolymerization device, making it more convenient to use and easy to store.

[0034] To ensure uniform microwave heating, the microwave generating unit 11 may include multiple subunits evenly distributed along the walls of the reaction chamber. This allows heat to be radiated from multiple directions, uniformly heating the biomass feedstock and preventing localized underheating or overheating that could affect product selectivity and conversion efficiency. In this embodiment, the reaction apparatus 10 is provided with, for example, an insulation layer to reduce heat loss and improve thermal efficiency.

[0035] In another embodiment, Figure 2 As shown, the reaction device 10 is built into the microwave generating unit 11, so that the microwaves generated by the microwave generating unit 11 penetrate the reaction device 10 and then act on the biomass feedstock and the heat transfer medium. In this embodiment, the microwave generating unit 11 and the reaction device 10 are separately arranged, which helps to reduce the production requirements of each structure. The reaction device 10 can be made of a variety of materials such as high-temperature resistant glass, ceramics, graphite, etc., which increases the design flexibility of the reaction device 10. At the same time, the microwave generating unit 11 surrounds the outside of the reaction device 10 to assist in heat preservation and reduce heat loss. In this embodiment, the microwave generating unit 11 has an inner cavity, and the reaction device 10 is arranged in the inner cavity of the microwave generating unit 11. The microwave generating unit 11 includes, for example, a magnetron (for generating microwaves), a frequency converter (for adjusting the frequency), and a waveguide.

[0036] Based on the above embodiment, as a preferred embodiment of the present invention, the coil 121 of the electromagnetic induction generating unit 12 is evenly wound around the outer wall of the reaction device 10. In this way, when the electromagnetic induction generating unit 12 is energized, a high-frequency alternating magnetic field generated by high-frequency alternating current can be transmitted to the coil 121, thereby generating eddy currents in the liquid metal in the reaction chamber, thereby generating heat energy.

[0037] Specifically, for the reaction device 10 in which the microwave generating unit 11 is embedded in the cavity wall of the reaction cavity, the reaction device 10 includes an inner shell and an outer shell. The reaction cavity is formed in the inner shell. The inner shell can be made of stainless steel, ceramic, glass, etc., and the outer shell can be made of metal, etc. The required material can be selected according to actual needs.

[0038] In the case where the reaction device 10 is built into the microwave generating unit 11, the reaction device 10 can be made of materials such as glass and ceramics, which can ensure the microwave absorption effect. At the same time, the electromagnetic induction generating unit 12 can transmit the high-frequency alternating magnetic field generated by the high-frequency alternating current to the coil 121, so that the metal heat transfer medium in the reaction device 10 generates eddy currents, thereby heating the biomass.

[0039] As a preferred embodiment of the present invention, Figure 3 As shown, the reaction device 10 is built into the microwave generating unit 11. A hot air component is provided on the upper part of the microwave generating unit 11. The hot air component includes a hot air fan 13 and a heating pipe 14. The air heated by the heating pipe 14 is blown toward the reaction device 10 under the action of the hot air fan 13.

[0040] Since the reaction device 10 is built into the microwave generating unit 11, the microwaves need to penetrate the reaction device 10 to act on the biomass therein. To compensate for the low heating efficiency and uneven heating that may occur with microwave heating, this embodiment uses a hot air assembly to blow hot air into the reaction device 10, increasing the heat source and thereby improving the heating effect of the biomass. The heating tube 14 can be, for example, an infrared heating tube that supplies heat to the reaction device 10 by emitting infrared radiation; or the heating tube 14 can be a light wave heating tube that irradiates the biomass within the reaction device 10 to provide compensatory heating to the biomass, thereby heating the biomass more evenly.

[0041] Furthermore, in one embodiment, the hot air assembly further includes a reflector, which is fixed to the inner top wall of the microwave generating unit 11. The hot air fan 13 and the heating tube 14 are sequentially arranged below the reflector. The reflector is used to radiate the heat of the heating tube 14 toward the reaction device 10. The provision of the reflector facilitates the downward concentration of the heat from the heating tube 14 so that it can fully act on the reaction device 10, thereby improving heat utilization and enhancing the reaction efficiency of the biomass.

[0042] As a preferred embodiment of the present invention, the first frequency is between 300 MHz and 300 GHz, and the second frequency is between 50 kHz and 300 kHz.

[0043] In specific implementations, microwaves can use a frequency of 915 MHz, for example, which is suitable for processing large biomass with high moisture content (such as wood and straw). At this wavelength, microwaves can penetrate deeply into the material, reducing surface overheating and internal unreacted products. Due to their deep penetration and more dispersed energy distribution, the temperature difference between the material interior and surface is smaller, reducing localized overheating and resulting in coking or side reactions. This also makes them suitable for large-scale, continuous depolymerization. Using a microwave frequency of 2.45 GHz can induce more intense molecular vibrations within the biomass, leading to rapid temperature rise, which is beneficial for small-scale depolymerization reactions. Furthermore, the depolymerization effect is better for low-moisture biomass (such as pre-dried straw and sawdust). It should be noted that the values of the first frequency mentioned above include the end values of the set range, i.e., 300 MHz and 300 GHz, although the value of the first frequency can also be any other value within this range. The values of the second frequency include the end values of the set range, i.e., 50 kHz and 300 kHz, although the value of the second frequency can also be any other value within this range.

[0044] On the basis of the above embodiments, the heat transfer medium of the present invention may be one of liquid metal, liquid metal-ionic liquid mixture and liquid metal-inorganic material composite.

[0045] The liquid metal is one or more of a metal, alloy, and metal derivative having a melting point below 300° C. In some embodiments, the liquid metal comprises sodium, potassium, a sodium-potassium alloy, gallium, bismuth, indium, tin, a gallium-indium alloy, a gallium-tin alloy, a gallium-indium-tin alloy, a bismuth-indium alloy, a bismuth-tin alloy, or a bismuth-indium-tin alloy, preferably one or more of gallium, bismuth, indium, tin, a gallium-indium alloy, a gallium-tin alloy, a gallium-indium-tin alloy, or a bismuth-indium alloy.

[0046] Furthermore, the liquid metal-ionic liquid mixture can use a gallium-based liquid metal combined with 1-ethyl-3-methylimidazolium tetrafluoroborate. The addition of the ionic liquid effectively inhibits metal oxidation, while the mixture remains stable in a liquid state at reaction temperatures above 300°C. Other possible combinations include bismuth-based liquid metal combined with 1-butyl-3-methylimidazolium hexafluorophosphate, sodium-potassium alloys combined with pyridine-based ionic liquids, and gallium-indium alloys combined with fluorine-containing ionic liquids.

[0047] Furthermore, the inorganic material may be in powder or fiber form, including ferrite powder, carbonyl iron powder, various ultrafine metal powders, silicon carbide powder, silicon carbide fiber, carbon fiber, metal fiber and organic high molecular polymer, preferably iron, nickel and silicon carbide.

[0048] As a preferred embodiment of the present invention, the reaction device 10 is provided with a temperature sensor 15 and a pressure sensor 16 for monitoring the temperature and pressure in the reaction chamber respectively. By understanding the temperature and pressure during the reaction process, the power and action time of the electromagnetic wave can be more accurately controlled to ensure that the reaction is carried out under optimal conditions. Figure 4 As shown, the temperature sensor 15 can be in the form of a thermocouple, for example, which is inserted into the reaction device 10 from the top downward. By reasonably arranging one or multiple thermocouples set at intervals, the temperature in the reaction chamber is monitored to ensure that the temperature in the reaction chamber is uniform, thereby ensuring that the biomass raw materials are fully and evenly depolymerized.

[0049] Furthermore, the biomass depolymerization device also includes a control system, and the electromagnetic wave generating device, the temperature sensor 15 and the pressure sensor 16 are all electrically connected to the control system. The control system can automatically adjust the power, working time and other parameters of the microwave generating unit 11 and the electromagnetic induction generating unit 12 according to the obtained temperature, pressure and other data to ensure that the reaction is carried out under optimal conditions. When an agitator is provided in the reaction device 10 or the mixing device, the control system can also control the speed of the agitator. When an agitator is provided in the reaction device 10, the agitator can not only work in the material mixing stage, but also work intermittently during the biomass depolymerization reaction process, so that the biomass raw material is stirred to promote uniform heating of the material everywhere, thereby achieving sufficient depolymerization of the biomass raw material.

[0050] As a preferred embodiment of the present invention, the biomass depolymerization device further includes a product collection device 17 connected downstream of the reaction device 10 for separating and collecting gaseous products, liquid products and solid products after depolymerization of the biomass raw materials.

[0051] For example, Figure 4 As shown, the product collecting device 17 is integrated with a condensing device 171, a filtering device 172, a distillation device 173 and a centrifugal separation device 174, etc., which can not only realize the efficient separation of gaseous, liquid and solid substances in the reaction products, but also realize the recovery of liquid metal at the same time, realize the recycling of liquid metal, reduce production costs and reduce resource waste.

[0052] Furthermore, the biomass depolymerization device also includes a pretreatment device for performing at least one of crushing, drying and impurity removal on the biomass raw materials to be treated, thereby creating conditions conducive to the depolymerization reaction of the biomass raw materials and allowing the biomass raw materials to fully react in a shorter time.

[0053] The biomass depolymerization method provided by the present invention is described below. The biomass depolymerization method described below and the biomass depolymerization device described above can be referred to each other.

[0054] Figure 5 This is one of the flow diagrams of the biomass depolymerization method provided by the present invention, such as Figure 5 As shown, the method includes the following: Step 100: mixing a biomass raw material to be processed with a heat transfer medium to obtain a reaction mixture, wherein the heat transfer medium is a liquid medium containing liquid metal; Step 200: emitting microwaves of a first frequency and an alternating magnetic field of a second frequency to the reaction mixture; the microwaves and the alternating magnetic field cooperate with a heat transfer medium to heat the biomass raw material to achieve depolymerization of the biomass raw material.

[0055] In step 100, the purpose of mixing the biomass raw material with the heat transfer medium is to make the biomass raw material fully contact with the heat transfer medium, such as making the biomass raw material completely immersed in the liquid medium, or at least making the liquid medium evenly attached to the surface of the biomass raw material to form a wrapping effect, so that the liquid medium can evenly transfer heat to the biomass raw material during the subsequent reaction process to ensure that all biomass raw materials are fully depolymerized.

[0056] The biomass raw material and the heat transfer medium are uniformly mixed in a mass ratio of 5:1-10:1. The mixing process can be carried out with the aid of an agitator such as a stirring paddle. For example, the stirring paddle is stirred at a speed of 150-200 r / min for 5-10 minutes to ensure that the biomass is fully in contact with the heat transfer medium.

[0057] In step 200, the electromagnetic wave generating device is started to enable the microwave generating unit to emit microwaves of 300MHz to 300GHz, and at the same time, the electromagnetic induction generating unit is enabled to emit an alternating magnetic field of 50kHz to 300kHz. Through the coordinated work of multiple heating effects, biomass heating is achieved to promote the depolymerization reaction of the biomass.

[0058] During the reaction process, the temperature and pressure inside the reaction device are monitored in real time by temperature sensors and pressure sensors. The control system is used to adjust the power and emission time of the electromagnetic wave to control the temperature at 400-600 °C and maintain the pressure at 0.1-0.3MPa.

[0059] Furthermore, the biomass depolymerization method further comprises: Step 300: Separate and collect the products after the depolymerization reaction. Specifically, by utilizing the differences in the physical and chemical properties of the different products, gaseous products (such as hydrogen, carbon monoxide, and methane, etc.), liquid products (bio-oil, mixtures containing liquid metals), and solid products (biochar, incomplete depolymerization residues) are separated through condensation, filtration, distillation, and other methods. Liquid metals mixed in the liquid products can be recovered by centrifugation or distillation for recycling.

[0060] Furthermore, the biomass depolymerization method further comprises: Step 400: Before mixing the biomass feedstock with the heat transfer medium, the biomass feedstock is pretreated. For example, the biomass feedstock is collected and impurities removed, and then crushed according to the feedstock type. Agricultural straw is crushed to a length of approximately 10-20 mm; forestry sawdust is crushed to a particle size of less than 5 mm. If the biomass feedstock has a high moisture content, it is dried to reduce the moisture content to 10%-15%.

[0061] The biomass depolymerization method of the present invention can be applied to the above-mentioned biomass depolymerization device. The advantages of the above-mentioned biomass depolymerization device are also possessed by the biomass depolymerization method, which will not be described in detail here.

[0062] The biomass depolymerization device and method provided by the present invention use electromagnetic waves in conjunction with a liquid medium containing liquid metal to form a heat source for depolymerizing biomass. It can quickly and deeply depolymerize the complex macromolecular structure of biomass. Compared with traditional biomass treatment methods, it improves the reaction rate and shortens the reaction time, while making biomass depolymerization more complete, significantly improving product selectivity, and ensuring the quality of various types of products. By utilizing the efficient heating characteristics of electromagnetic waves and the good thermal conductivity of liquid metal, the high heat demand in traditional thermochemical treatment is reduced, and compared with traditional pyrolysis technology, energy consumption can be effectively reduced; the reaction process reduces the generation of pollutants in traditional biomass treatment processes, such as a significant reduction in the amount of tar generated during pyrolysis, while achieving the full utilization of biomass components, which is in line with the concepts of sustainable development and green chemistry. The heat transfer medium only serves as a medium and catalyst during the reaction process. After the reaction is completed, it can be recovered and reused through simple separation means, reducing production costs and reducing resource waste.

[0063] The present invention can be used to process various types of biomass raw materials, including different types of agricultural waste, forestry waste, and energy crops, and has relatively loose requirements on the quality and form of the raw materials, thereby broadening the scope of biomass resource utilization.

[0064] The following describes the method for depolymerizing different types of biomass raw materials with reference to specific examples.

[0065] Example 1: Pretreatment: Corn stalks were selected as biomass raw materials and crushed into about 15 mm in length using a grinder. They were then placed in a dryer and dried at 80 °C to a moisture content of 12%.

[0066] Mixing treatment: Add the dried corn stalks and gallium-indium alloy into a mixing container at a mass ratio of 8:1, start the stirrer, stir at a speed of 180 r / min for 8 minutes, and after the two are fully mixed, transfer them to the reaction device.

[0067] Electromagnetic wave co-processing: The microwave generator was set to 2.45 GHz and a power of 1200 W. Simultaneously, the electromagnetic induction generator was activated, with a frequency of 100 kHz and a power of 900 W. During the reaction, a temperature sensor monitored the temperature inside the reactor in real time. When the temperature reached 500°C, the control system automatically adjusted the power of the microwave and electromagnetic induction devices to maintain a stable temperature of 500 ± 10°C and a pressure of approximately 0.2 MPa. After the reaction continued for 30 minutes, the electromagnetic wave generator was turned off.

[0068] Product separation and collection: After the reaction is completed, the reaction products are first cooled by a condenser to collect the synthesis gas. The remaining liquid and solid mixture is filtered to separate the biochar and liquid mixture. The liquid mixture is then purified by a distillation device to obtain high-quality bio-oil. Finally, the residue containing liquid metal is centrifuged by a centrifugal separation device to recover the liquid metal for future use. After testing, the synthesis gas yield was 45%, the H2 / CO ratio was 0.8:1, and the calorific value was 18MJ / m 3 , the bio-oil yield is 35%, and the specific surface area of biochar is 300m 2 / g.

[0069] Example 2: Pretreatment: Collect pine wood chips and crush them into particles less than 3mm in size using a crusher. The moisture content is 8% after testing, so no drying is required.

[0070] Mixing treatment: Pine wood chips and gallium-indium-tin alloy were added into a mixing container at a mass ratio of 6:1, stirred at a speed of 200 r / min for 6 minutes, and transferred to a reaction device after mixing evenly.

[0071] Electromagnetic wave co-processing: The microwave generator was operated at 2.45 GHz and set to 1300 W. Simultaneously, the electromagnetic induction generator was turned on at 150 kHz and 1000 W. The control system maintained the temperature at 550°C and the pressure at 0.25 MPa based on data from the temperature and pressure sensors. The reaction lasted for 25 minutes.

[0072] Product Separation and Collection: The reaction products were separated and processed using a similar separation process as in Example 1. The resulting products were syngas, bio-oil, biochar, and recovered liquid metal. Analysis showed a syngas yield of 65%, an H2 / CO ratio of 1.6:1, and a bio-oil yield of 25%. The oxygenated compound content in the bio-oil was 35% lower than that of conventional methods. The biochar can be used to prepare activated carbon.

[0073] Example 3: Pretreatment: Bagasse was selected as the biomass raw material, which was crushed and dried to a moisture content of 13%.

[0074] Mixing treatment: Bagasse and indium tin alloy were fully stirred in a mixing container at a mass ratio of 10:1 at a stirring speed of 160 r / min for 7 min, and then the mixture was transferred to a reaction device.

[0075] Electromagnetic wave co-processing: The microwave generator was operated at 915 MHz and set to 1100 W. Simultaneously, the electromagnetic induction generator was activated, adjusted to 200 kHz, and set to 850 W. The reaction was maintained at a temperature of 480°C and a pressure of 0.18 MPa for 32 min.

[0076] Product Separation and Collection: Products are separated and collected through condensation, filtration, distillation, and centrifugation. Testing showed a syngas yield of 50% and an H2 / CO ratio of 1.3:1. The syngas can be used as a raw material for synthesizing value-added chemicals. The bio-oil yield was 25%, which can be used as a chemical raw material for coatings. The liquid metal recovery rate reached 98%, achieving efficient biomass utilization and liquid metal recycling.

[0077] The application of the biomass depolymerization device or method of the present invention can significantly improve the quality of the biomass depolymerization product. The content of oxygen-containing compounds in the bio-oil is reduced by 30%-40%, and the quality is significantly improved. It can be directly used as fuel or as a chemical raw material; the content of combustible gases such as hydrogen and carbon monoxide in the synthesis gas is increased, and the calorific value is increased by 20%-30%; the specific surface area of the biochar is increased, and the adsorption performance is enhanced, which can be used to prepare high-performance adsorption materials or electrode materials.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A biomass depolymerization device, characterized in that: include: A reaction device (10) having a reaction chamber, wherein the reaction chamber provides a space for accommodating a biomass raw material to be processed and a heat transfer medium, wherein the heat transfer medium is a liquid medium containing liquid metal, and the heat transfer medium is distributed on the surface of the biomass raw material; An electromagnetic wave generating device comprises a microwave generating unit (11) and an electromagnetic induction generating unit (12), wherein the microwave generating unit (11) is used to emit microwaves of a first frequency to the reaction chamber, and the electromagnetic induction generating unit (12) is used to emit an alternating magnetic field of a second frequency to the reaction chamber, wherein the microwaves and the alternating magnetic field cooperate with the heat transfer medium to heat the biomass raw material to achieve depolymerization of the biomass raw material.

2. The biomass depolymerization device according to claim 1, characterized in that: The microwave generating unit (11) is embedded in the cavity wall of the reaction cavity, so that the microwaves generated by the microwave generating unit (11) directly act on the biomass raw material and the heat transfer medium; Alternatively, the reaction device (10) is built into the microwave generating unit (11), so that the microwaves generated by the microwave generating unit (11) penetrate the reaction device (10) and then act on the biomass raw material and the heat transfer medium.

3. The biomass depolymerization device according to claim 2, characterized in that: The coil (121) of the electromagnetic induction generating unit (12) is evenly wound on the outer wall of the reaction device (10).

4. The biomass depolymerization device according to claim 1, characterized in that: The reaction device (10) is built into the microwave generating unit (11). A hot air component is provided on the upper portion of the microwave generating unit (11). The hot air component comprises a hot air fan (13) and a heating pipe (14). The air heated by the heating pipe (14) is blown toward the reaction device (10) under the action of the hot air fan (13).

5. The biomass depolymerization device according to claim 4, characterized in that: The hot air assembly further includes a reflective cover, which is fixed on the inner top wall of the microwave generating unit (11). The hot air fan (13) and the heating tube (14) are sequentially arranged below the reflective cover, and the reflective cover is used to radiate the heat of the heating tube (14) to the reaction device (10).

6. The biomass depolymerization device according to claim 1, characterized in that: The first frequency is between 300 MHz and 300 GHz, and the second frequency is between 50 kHz and 300 kHz.

7. The biomass depolymerization device according to claim 1, characterized in that: The heat transfer medium is one of liquid metal, liquid metal-ionic liquid mixture and liquid metal-inorganic material composite.

8. The biomass depolymerization device according to any one of claims 1 to 7, characterized in that: The reaction device (10) is provided with a temperature sensor (15) and a pressure sensor (16) for respectively monitoring the temperature and pressure in the reaction chamber.

9. The biomass depolymerization device according to claim 8, characterized in that: Also includes: a product collecting device (17), connected to the downstream of the reaction device (10), for separating and collecting the gaseous products, liquid products and solid products after depolymerization of the biomass raw material; And / or, a pretreatment device is used to crush, and / or dry, and / or remove impurities from the biomass raw materials to be treated.

10. A biomass depolymerization method, characterized in that: The biomass depolymerization device according to any one of claims 1 to 9 comprises the following steps: Mixing a biomass raw material to be processed with a heat transfer medium to obtain a reaction mixture, wherein the heat transfer medium is a liquid medium containing liquid metal; Microwaves of a first frequency and an alternating magnetic field of a second frequency are emitted to the reaction mixture, and the microwaves and the alternating magnetic field cooperate with the heat transfer medium to heat the biomass raw material to achieve depolymerization of the biomass raw material.

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