Method and system for preparing high-quality bio-oil by biomass pyrolysis

Abstract

The invention relates to a method and a system for preparing high-quality bio-oil by biomass pyrolysis, belongs to the technical field of biomass oil preparation, and aims to reduce the production cost and improve the conversion efficiency and the product yield. The method comprises a pretreatment step, a drying step, a pyrolysis step and an oil collection step which are carried out in sequence. According to the method, an ultrasonic rotational flow deashing technology is combined with a suspended bed rotational flow drying and pyrolysis process, so that a scheme for efficiently converting biomass is formed, and high-quality bio-oil is successfully prepared. The method integrates the advantages of low consumption and high-efficiency deashing of ultrasonic rotational flow and the characteristic of high-efficiency mass and heat transfer in the drying and pyrolysis process of a controllable suspension rotational flow mode, not only obviously improves the conversion efficiency of biomass, the quality of bio-oil and the product yield, but also is green, environment-friendly, lower in cost and suitable for industrial production. And a new scheme with economical efficiency and sustainability is provided for preparing the bio-oil from the biomass (especially waste biomass).

Description

Technical Field

[0001] This invention belongs to the field of biomass oil production technology, specifically relating to a method and system for preparing high-quality bio-oil using biomass pyrolysis. Background Technology

[0002] There are numerous ways to utilize biomass resources. Given the current shortage of liquid fuels, converting biomass into liquid fuels that can replace fossil fuels through modern technology is of great significance. Rapid biomass pyrolysis technology has attracted much attention due to its advantages such as "high bio-oil yield and efficient energy conversion." Conventional rapid pyrolysis devices mainly include fixed-bed reactors, fluidized-bed reactors, and plasma reactors. However, these reactors suffer from problems such as high oxygen content, strong acidity, low pyrolysis efficiency, and high residual pyrolysis char in bio-oil production. Furthermore, biomass contains a large amount of inorganic elements, and it is difficult to remove these elements using simple and environmentally friendly methods without causing biomass framework collapse and component loss. These inorganic elements are prone to deposition or fly ash generation during pyrolysis, leading to pipeline blockage and even air pollution.

[0003] Chinese invention patent with authorization announcement number CN110467940B discloses a method for producing liquid fuel from biomass. The method uses biomass for pretreatment, pyrolysis and catalytic cracking to obtain liquid fuel. The biomass consists of pine needles, bamboo, tung tree branches, ginger stalks and leaves, toon tree branches, sweet potato vines, seaweed, and slaughterhouse waste. The specific pretreatment method is as follows: First, pine needles, bamboo, tung tree branches, ginger stalks and leaves, toon tree branches, sweet potato vines, and seaweed are each pulverized and mixed according to the formula. This mixture is then poured into a 2-3% hydrogen peroxide solution and stirred at 55-60°C for 60-70 minutes. After washing, it is added to a 3-5% acetic acid solution and stirred at 40-50°C for 50-60 minutes. After washing, it is dried to a moisture content of 4-5 wt.% to obtain the mixture. The seaweed is obtained by washing and sun-drying freshly harvested seaweed, then heating and drying it at 110-120°C for 2-3 hours. Finally, the slaughterhouse waste in the formula is heated and filtered. A mixture is obtained; finally, the mixture is mixed with the liquid to obtain the pretreated product; after the pyrolysis reaction, pyrolysis gas and residue are generated. The pyrolysis gas is passed into a first reactor containing a catalyst to carry out a catalytic cracking reaction to obtain a first part of the catalytic cracking product. The residue is transferred to a second reactor containing a composite additive to carry out a catalytic cracking reaction to obtain a second part of the catalytic cracking product. Finally, the first part of the catalytic cracking product and the second part of the catalytic cracking product are mixed and processed. The catalyst is obtained by mixing aluminum dihydrogen phosphate and zirconium nitride in a mass ratio of 1:0.2-0.3. The composite additive is obtained by mixing and grinding ferrocene, zirconium nitride, isooctyl nitrate and acetamide in a mass ratio of 1:0.5-0.6:1.5-2:0.3-0.4 until the average particle size is less than 300 μm.

[0004] Although the above-mentioned method for producing liquid fuel by using biomass can fully convert the biomass raw material through pyrolysis reaction and catalytic cracking reaction, and the combustion quality of the obtained liquid fuel is excellent, in order to improve the pretreatment effect, a large amount of chemical agents are added, and the acid-containing wastewater generated needs to be treated additionally, which not only increases the production cost, but also may cause environmental pollution. At the same time, high-temperature drying treatment is used, which has high energy consumption, further increasing the production cost of the liquid fuel. In addition, the pyrolysis method is single, the pyrolysis efficiency is not high, and the product yield of the liquid fuel is low. SUMMARY

[0005] The present application provides a method and system for preparing high-quality bio-oil by pyrolysis of biomass, aiming to reduce production cost and improve conversion efficiency and product yield.

[0006] The technical scheme adopted by the present application to solve the technical problem is: a method for preparing high-quality bio-oil by pyrolysis of biomass, comprising pretreatment step, drying step, pyrolysis step and oil collection step in sequence;

[0007] The pretreatment step is: after crushing the biomass, the biomass is added into a container together with a liquid deashing medium, and the ash in the biomass is removed through ultrasonic cyclone coupling treatment, and after deashing, the pretreated material is obtained through solid-liquid separation;

[0008] The drying step is: the pretreated material is subjected to controllable suspension cyclone drying treatment, so that the water content is reduced to below 10%, and the dried material is obtained;

[0009] The pyrolysis step is: the dried material is subjected to controllable suspension cyclone pyrolysis treatment, and pyrolysis oil gas and pyrolysis carbon are obtained;

[0010] The oil collection step is: the pyrolysis oil gas is subjected to low-temperature condensation treatment, and incondensable pyrolysis gas and high-quality bio-oil are separated; the yield of high-quality bio-oil is ≥40%, and the nitrogen content is ≤1.5% and the oxygen content is ≤40.5%.

[0011] Further, the biomass is waste biomass, which is at least one of corn straw, wheat straw, rice straw, vinasse, rice husk, sludge, wood chips, walnut shells and livestock manure.

[0012] Further, the ultrasonic cyclone coupling treatment is: the solid-liquid mixture of biomass particles and liquid deashing medium is treated by dynamically superimposing the cavitation effect of ultrasonic waves and the centrifugal field of cyclone field to remove the ash in the biomass; the ultrasonic cyclone coupling treatment time is 0.5-4h, the cyclone field angular velocity is 20-105rad / s, the ultrasonic wave frequency is 20-80kHz, and the ultrasonic wave power density is 1-5w / cm 3 ;

[0013] and / or, the controllable suspension cyclone drying treatment is: using a carrier gas to carry the pretreated material to form a cyclone field, so that the biomass particles produce self-rotation coupling motion and are in a stable suspension state, so as to realize rapid dewatering and drying; in the controllable suspension cyclone drying treatment process: the temperature is room temperature, the carrier gas used is air, and the gas-solid ratio of the air to the pretreated material is 8-16 m 3 / kg;

[0014] and / or, the controllable suspension cyclone pyrolysis treatment is: using a carrier gas to carry the dry material to form a cyclone field, so that the biomass particles produce self-rotation coupling motion and are in a stable suspension state, and realize rapid pyrolysis at high temperature; in the controllable suspension cyclone pyrolysis treatment process: the pyrolysis temperature is 450-600 DEG C, the pyrolysis time is 10-40 min, the carrier gas used is nitrogen, and the gas-solid ratio of the nitrogen to the dry material is 10-50 m 3 / kg;

[0015] and / or, the low-temperature condensation treatment is: under the condition of-25 DEG C to-15 DEG C, the pyrolysis oil gas is condensed and separated into non-condensed pyrolysis gas and high-quality bio-oil.

[0016] Further, in the low-temperature condensation treatment process, the condensing agent is used for heat exchange with the pyrolysis oil gas to condense and separate it;

[0017] The oil collection step further includes using an organic solvent spraying process to collect and separate the high-quality bio-oil.

[0018] The application also provides a system for preparing high-quality bio-oil by biomass pyrolysis, which is used for realizing the method for preparing high-quality bio-oil by biomass pyrolysis and comprises an ultrasonic cyclone device, a suspension bed cyclone drying device, a suspension bed cyclone pyrolysis device and a condensation and oil collection device.

[0019] The ultrasonic cyclone device is used for ultrasonic cyclone coupling treatment of a solid-liquid mixture of biomass particles and liquid deashing medium, so as to remove the ash in the biomass and obtain pretreated material; the ultrasonic cyclone device comprises a medium tank, a stirring mechanism, an ultrasonic transducer and a solid-liquid separator.

[0020] The tank cavity of the medium tank is a deashing cavity, and the bottom of the deashing cavity is provided with a solid-liquid discharge port.

[0021] The stirring mechanism is arranged on the medium tank, and the stirring paddle thereof is in the deashing cavity, and is used for stirring the solid-liquid mixture in the deashing cavity to form a cyclone.

[0022] The ultrasonic transducer is arranged in the deashing cavity and is used for emitting ultrasonic waves to excite cavitation effect and acoustic streaming effect in the solid-liquid mixture in the deashing cavity.

[0023] The feed inlet of the solid-liquid separator is connected with the solid-liquid outlet, and is used for separating the solid-liquid mixture treated by the ultrasonic cyclone coupling device;

[0024] The suspension bed cyclone drying device can use the carrier gas to carry the pretreated material to form a cyclone field, and make the biomass particles produce a self-rotation coupling motion to be in a stable suspension state, so as to realize rapid dewatering and drying, and obtain dried material;

[0025] The suspension bed cyclone pyrolysis device can use the carrier gas to carry the dried material to form a cyclone field, and make the biomass particles produce a self-rotation coupling motion to be in a stable suspension state, and realize rapid pyrolysis at high temperature, so as to obtain pyrolysis oil gas and pyrolysis carbon;

[0026] The condensation oil collecting device is used for condensing and separating the pyrolysis oil gas, and collecting high-quality bio-oil.

[0027] Further, the ultrasonic cyclone device further comprises a first feeding hopper and a liquid injection pump;

[0028] The first feeding hopper is arranged on the medium tank, and the discharge port thereof is communicated with the deashing cavity, and is used for adding the biomass particles into the deashing cavity.

[0029] The liquid injection pump is arranged on the medium tank, and the liquid outlet thereof is communicated with the deashing cavity, and is used for pumping the liquid deashing medium into the deashing cavity.

[0030] Further, an isolation plate in an open type is arranged in the inner cavity of the solid-liquid separator, the isolation plate separates the inner cavity of the solid-liquid separator into a separation cavity in the upper part and a storage bin in the lower part, a liquid discharge port communicated with the separation cavity is arranged on the solid-liquid separator, and a filter structure is arranged at the liquid discharge port.

[0031] Further, the suspension bed cyclone drying device comprises a cyclone dryer, a first feeding mechanism and a cyclone separator.

[0032] The cyclone dryer comprises a dryer main body, a first overflow discharge pipe and a first bypass riser pipe; the bottom of the dryer main body is provided with a dryer bottom opening, and a first multi-way connector is connected with the dryer bottom opening; the first multi-way connector has a first connecting port and a second connecting port communicated correspondingly, and a third connecting port communicated with the first connecting port and / or the second connecting port; the third connecting port is connected with the dryer bottom opening; the first overflow discharge pipe is arranged at the upper end of the dryer main body, and the lower part thereof extends into the upper part of the inner cavity of the dryer main body, and the dryer main body and the first overflow discharge pipe jointly form a first annular channel; the side of the dryer main body is provided with a first tangential feeding port communicated with the first annular channel; the lower end of the first bypass riser pipe is connected with the second connecting port, and the upper end of the first bypass riser pipe is connected with the first tangential feeding port.

[0033] The first feeding mechanism includes a second feeding hopper, a first screw feeder, and a first blower; the inlet of the second feeding hopper is connected to the outlet of the ultrasonic vortex device; the inlet of the first screw feeder is connected to the outlet of the second feeding hopper, and the outlet of the first screw feeder is connected to a first connection port; the outlet of the first blower is connected to the feeding channel of the first screw feeder or to the first connection port.

[0034] The cyclone separator has a second tangential feed inlet, an overflow exhaust pipe and a dry material outlet. The second tangential feed inlet is connected to the outlet of the first overflow discharge pipe, and a receiving bin is connected to the dry material outlet.

[0035] Furthermore, the suspended bed cyclone pyrolysis device includes a cyclone pyrolyzer, a second feeding mechanism, and a carbon storage bin;

[0036] The cyclone pyrolyzer includes a pyrolyzer body, a second overflow pipe, a second bypass riser, and a pyrolysis heater. The bottom of the pyrolyzer body has a pyrolyzer bottom port and a second multi-port connector connected to the bottom port. The second multi-port connector has a fifth and a sixth port correspondingly connected, a seventh port connected to the fifth and / or sixth port, and an eighth port correspondingly connected to the seventh port. The seventh port is connected to the bottom port. The second overflow pipe is located at the upper end of the pyrolyzer body, with its lower part extending into the upper part of the inner cavity of the pyrolyzer body, forming a second annular channel with the pyrolyzer body. The side of the pyrolyzer body has a third tangential feed port connected to the second annular channel. The lower end of the second bypass riser is connected to the sixth port, and the upper end is connected to the third tangential feed port. The pyrolysis heater is located on the pyrolyzer body and is used to heat the material inside the pyrolyzer body.

[0037] The second feeding mechanism includes a third feed hopper, a second screw feeder, a second blower, and a gas preheater; the feed inlet of the third feed hopper is connected to the discharge outlet of the cyclone dryer; the feed inlet of the second screw feeder is connected to the discharge outlet of the third feed hopper, and the discharge outlet of the second screw feeder is connected to a fifth connection port; the second blower is connected to the feeding channel of the first screw feeder through the gas preheater or to the fifth connection port;

[0038] The feed inlet of the carbon storage bin is connected to the eighth connection port.

[0039] Furthermore, the condensation and oil collection device includes a condenser, a sprayer, and a product collection tank;

[0040] The inner cavity of the condenser is a condensation chamber. The condenser is provided with a pyrolysis oil and gas inlet pipe that communicates with the bottom of the condensation chamber, a tail gas outlet that communicates with the top of the condensation chamber, and a bio-oil outlet that communicates with the bottom of the condensation chamber. The inlet of the pyrolysis oil and gas inlet pipe is connected to the outlet of the slurry bed cyclone pyrolysis device.

[0041] The sprayer is installed on the inner top surface of the condenser, with its nozzle facing the condensation chamber;

[0042] The inlet of the product collection tank is connected to the bio-oil outlet.

[0043] The beneficial effects of this invention are as follows:

[0044] 1) This invention employs an ultrasonic vortex coupling treatment method with zero reagent addition to pretreat biomass. By dynamically superimposing the cavitation effect of ultrasound with the centrifugal force field of the vortex field, the cavitation effect under the ultrasonic vortex field is fully utilized to release a large number of hydroxyl radicals, which can promote the removal of a large number of unfavorable inorganic elements in biomass, thereby improving the quality of bio-oil and alleviating problems such as equipment corrosion and pipeline blockage. In addition, the ultrasonic vortex coupling treatment method also has the advantages of low energy consumption and cost, no secondary pollution, and environmental friendliness.

[0045] 2) This invention uses a controllable suspension cyclone drying process to dry and dehydrate pretreated materials. It can be carried out at room temperature and pressure. It not only utilizes the self-revolution-suspension recirculation coupled motion of biomass particles in the cyclone field to enhance the dehydration efficiency of biomass particles, but also extends the effective treatment time of biomass particles in the suspension-cyclone field, so as to achieve low-energy consumption and high-efficiency drying of biomass particles.

[0046] 3) This invention employs a controllable suspension swirling pyrolysis process to thermally decompose dried materials. It can utilize the oscillation and swirling effect of airflow under thermal conditions to achieve dual regulation of the suspension and swirling of biomass particles, thereby enhancing the real-time updating of mass and heat transfer on the surface of biomass particles. Compared with traditional pyrolysis processes, this invention not only achieves efficient pyrolysis of biomass particles, but also effectively avoids further condensation of volatiles in a high-gas-velocity environment, thus improving the yield of the product (high-quality bio-oil).

[0047] 4) This invention combines ultrasonic cyclone deashing technology with suspended bed cyclone drying and pyrolysis processes to form a highly efficient biomass conversion scheme, successfully producing high-quality bio-oil. It integrates the advantages of ultrasonic cyclone deashing (low energy consumption and high efficiency) with the efficient mass and heat transfer characteristics of controllable suspended cyclone drying and pyrolysis. This not only significantly improves biomass conversion efficiency, bio-oil quality, and product yield, but is also environmentally friendly and lower in cost, providing a new, economical, and sustainable solution for biomass (especially waste biomass) bio-oil production.

[0048] The technical effects brought about or directly generated by other technical features of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the implementation structure of the system of the present invention;

[0050] Figure 2 This is a schematic diagram of the implementation structure of the ultrasonic vortex device in the system of the present invention;

[0051] Figure 3 This is a schematic diagram of the implementation structure of the suspension bed cyclone drying device in the system of the present invention;

[0052] Figure 4 This is a schematic diagram of the implementation structure of the suspended bed cyclone pyrolysis device in the system of the present invention;

[0053] Figure 5 This is a schematic diagram of the implementation structure of the condensation and oil collection device in the system of the present invention;

[0054] The diagram is labeled as follows: 1-Ultrasonic cyclone device; 101-First feed hopper; 102-Ultrasonic transducer; 103-Stirring motor; 104-Liquid injection pump; 105-Media tank; 106-Solid-liquid separator; 107-Isolation plate; 108-Storage bin; 109-Solid-liquid outlet; 110-Drain outlet; 2-Suspension bed cyclone drying device; 201-First screw feeder; 202-First blower; 203-Cyclone dryer; 204-Receiving bin; 205-First bypass lift pipe; 206-First overflow outlet pipe; 207-Cyclone separator; 208-Overflow exhaust pipe; 209-Second feed hopper. 210-Dryer bottom opening; 211-First tangential feed inlet; 3-Suspension bed cyclone pyrolysis device; 301-Second screw feeder; 302-Second blower; 303-Gas preheater; 304-Cyclone pyrolyzer; 305-Pyrolysis heater; 306-Third feed hopper; 307-Pyrolyzer bottom opening; 308-Second bypass riser; 309-Third tangential feed inlet; 310-Second overflow outlet pipe; 311-Coal storage bin; 4-Condensation and oil collection device; 401-Condenser; 402-Sprayer; 403-Product collection tank; 404-Tail gas outlet; 405-Pyrolysis oil and gas inlet pipe. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings and embodiments. The same reference numerals in the drawings denote components with the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0056] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or position and dimensional relationship based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of description and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0057] In the description of this invention, "connection" can be a direct connection or an indirect connection formed by an intermediate medium or material flow. "Room temperature" means 25±5°C. "Ambient pressure" usually refers to standard atmospheric pressure. Unless otherwise specified, all percentage contents mentioned in this invention refer to mass percentages. The term "biomass" includes all plants, microorganisms, and animals that feed on plants and microorganisms and their waste products. The term "transmission connection" refers to a connection method used to transmit power or motion in a mechanical system, such as direct connection or connection through transmission mechanisms such as couplings, reducers, gear assemblies, and worm gear assemblies. The term "rotatably set or connected" refers to a connection method between two parts that allows one part to rotate relative to the other; this connection method is usually achieved using mechanical components such as bearings, bushings, and shaft-hole fits. The term "high-quality bio-oil" refers to a liquid fuel product obtained from the decomposition of biomass, which has higher stability, higher calorific value, and higher quality components compared to traditional bio-oil, and is therefore more valuable. The terms "about" and "around" when used to describe numerical ranges usually indicate an allowable error within ±2%. When the term "many" indicates quantity, it usually refers to three or more; for example, "multiple" typically means three or more. The expression "mainly composed of or constitutes" implies that it may also contain structural components not mentioned in the sentence. The term "and / or" merely describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone. Furthermore, the terms "first," "second," and "third," etc., are used only for descriptive purposes and should not be interpreted as indicating or implying relative importance.

[0058] A method for preparing high-quality bio-oil using biomass pyrolysis includes a pretreatment step, a drying step, a pyrolysis step, and an oil collection step performed sequentially.

[0059] The pretreatment steps are as follows: After crushing the biomass, it is added to a container along with a liquid deashing medium. The ash is removed from the biomass through ultrasonic vortex coupling treatment. After deashing, solid-liquid separation is performed to obtain the pretreated material. In this step, the biomass is generally crushed into particles with an average diameter of <5mm. The liquid deashing medium is usually water or a water-based solution. The ultrasonic vortex coupling treatment involves dynamically superimposing the cavitation effect of ultrasound with the centrifugal force field of the vortex field to form an ultrasonic vortex field, which treats the solid-liquid mixture of biomass particles and the liquid deashing medium. This treatment method fully utilizes the cavitation effect under the ultrasonic vortex field, releasing a large number of hydroxyl radicals, promoting the removal of a large amount of undesirable inorganic elements from the biomass. It not only has low energy consumption but also requires no added reagents, making it environmentally friendly and cost-effective. The removal rate of elements such as K, Na, and Fe, which are prone to corroding equipment, from the biomass ash is close to 100%. Solid-liquid separation is usually carried out using methods such as sedimentation, filtration, and centrifugation.

[0060] The drying step is as follows: the pretreated material is subjected to controlled suspension cyclone drying to reduce its moisture content to below 10%, thus obtaining dried material. This step can increase the calorific value of the raw material and reduce the energy consumption of subsequent pyrolysis. The controlled suspension cyclone drying process involves using a carrier gas to carry the pretreated material to form a cyclone field, causing the biomass particles to undergo self-revolution coupled motion and thus be in a stable suspension state, thereby achieving rapid dehydration and drying. This treatment method can be carried out at room temperature and pressure. It not only utilizes the self-revolution-suspension recirculation coupled motion of the biomass particles in the cyclone field to enhance the dehydration efficiency of the biomass particles, but also extends the effective treatment time of the biomass particles in the suspension-cyclone field, enabling low-energy and high-efficiency drying of biomass particles.

[0061] The pyrolysis steps are as follows: the dried material is subjected to controlled suspension cyclone pyrolysis to obtain pyrolysis oil and gas and pyrolysis char. The controlled suspension cyclone pyrolysis process involves using a carrier gas to carry the dried material to form a cyclone field, causing the biomass particles to undergo self-rotation coupled motion and thus be in a stable suspension state, achieving rapid pyrolysis at high temperature. This treatment method can utilize the oscillation and cyclone effect of the airflow in a thermal environment to achieve dual control of the suspension and cyclone of biomass particles, enhancing the real-time update of mass and heat transfer on the surface of the biomass particles. This not only achieves efficient pyrolysis of biomass particles, but also the high gas velocity environment can effectively avoid further condensation of volatiles, improving product yield.

[0062] The oil recovery process involves: subjecting the pyrolysis oil and gas to low-temperature condensation treatment to separate non-condensable pyrolysis gas and high-quality bio-oil; the yield of high-quality bio-oil is ≥40%, with a nitrogen content ≤1.5% and an oxygen content ≤40.5%; the temperature of the low-temperature condensation treatment is generally determined based on the boiling point of the hydrocarbon components in the pyrolysis oil and gas.

[0063] This method combines the advantages of low energy consumption and high efficiency of ultrasonic swirling for deashing with the characteristics of efficient mass and heat transfer during drying and pyrolysis by controllable suspension swirling. It is particularly suitable for the preparation of high-quality bio-oil from high-ash materials. It not only significantly improves the conversion efficiency of biomass, the quality of bio-oil and the product yield, but is also green, environmentally friendly and lower in cost.

[0064] Common high-ash materials include corn stalks, wheat stalks, rice stalks, distiller's grains, rice husks, sludge, sawdust, walnut shells, livestock manure, and other waste biomass. One or more of these materials can be used as raw materials for the preparation of high-quality bio-oil in this invention.

[0065] In some embodiments, the ultrasonic swirling coupling treatment time is 0.5–4 hours, the angular velocity of the swirling field is 20–105 rad / s, the frequency of the ultrasonic wave is 20–80 kHz, and the power density of the ultrasonic wave is 1–5 W / cm². 3 By controlling and matching the ultrasonic and vortex parameters, the effect of ultrasonic vortex coupling treatment can be further optimized. For example, a combination of low-frequency, high-energy ultrasonic parameters (20kHz + 5w / cm²) can be used. 3 This can generate strong cavitation. During ash removal, a high-speed vortex (100 rad / s) can instantly remove the ash through strong shearing and centrifugal force, preventing re-adsorption. For example, using high-frequency ultrasound (80 kHz) combined with a medium-high speed vortex (60 rad / s) can ensure uniform cavitation, release a large number of hydroxyl radicals, and ensure thorough mixing and mass transfer. Another example is using high-power-density ultrasound (5 W / cm²). 3 Combining high-speed vortex (100 rad / s) with low-power density ultrasound can shorten the processing time to about 0.5 hours, resulting in high efficiency; conversely, low-power density ultrasound (1 W / cm²) can be used for high-speed vortex (100 rad / s). 3 The combination of low-speed swirl (20 rad / s) and slow swirl is time-consuming, but it is suitable for biomass that requires gentle treatment to maximize the protection of the biomass structure.

[0066] In some embodiments, during the controlled suspension cyclone drying process: the temperature is room temperature, the carrier gas used is air, and the gas-solid ratio of air to pretreated material is 8–16 m³. 3 / kg, to ensure the drying efficiency and effect of the pretreated materials. The gas-solid ratio of air to pretreated materials is generally determined based on factors such as the specific gravity of the pretreated materials and the size of the suspension-swirl field.

[0067] In some embodiments, during the controlled suspension cyclone pyrolysis process: the pyrolysis temperature is 450–600°C, the pyrolysis time is 10–40 min, the carrier gas used is nitrogen, and the gas-solid ratio of nitrogen to the dried material is 10–50 m³ / g. 3 / kg, to ensure the efficiency and effectiveness of pyrolysis of the dried material. The pyrolysis temperature and time are generally determined based on factors such as the characteristics of the biomass feedstock, the composition of the target product, and the heat and mass transfer effects of the suspension-swirl flow field. The gas-solid ratio of nitrogen to the dried material is generally determined based on factors such as the specific gravity of the dried material and the size of the suspension-swirl flow field.

[0068] Preferably, in order to further improve the product yield, in some embodiments, the low-temperature condensation treatment is: under the condition of -25 to -15°C, the pyrolysis oil and gas are condensed and separated into non-condensable pyrolysis gas and high-quality bio-oil.

[0069] Specifically, based on the previous embodiment, the low-temperature condensation process utilizes a condenser to exchange heat with the pyrolysis oil and gas, causing them to condense and separate. The condenser is the heat exchange medium, which can be of various types, preferably a mixed solution of ethylene glycol and water, and more preferably an aqueous solution with an ethylene glycol content of 30-60 wt.%.

[0070] Preferably, for safe and efficient oil recovery, based on the previous embodiment, the oil recovery step further includes collecting the separated high-quality bio-oil using an organic solvent spraying process. The organic solvent spraying process involves intermittent high-pressure spraying using an organic solvent. The organic solvent can be various, preferably ethanol or acetone, or a mixture of ethanol and acetone.

[0071] Combination Figures 1 to 5 As shown, a system for preparing high-quality bio-oil using biomass pyrolysis is used to realize the above-mentioned method for preparing high-quality bio-oil using biomass pyrolysis. It includes an ultrasonic cyclone device 1, a suspended bed cyclone drying device 2, a suspended bed cyclone pyrolysis device 3, and a condensation and oil collection device 4.

[0072] The ultrasonic cyclone device 1 is used to perform ultrasonic cyclone coupling treatment on the solid-liquid mixture of biomass pellets and liquid deashing medium to remove ash from the biomass and obtain pretreated material; the ultrasonic cyclone device 1 includes a medium tank 105, a stirring mechanism, an ultrasonic transducer 102 and a solid-liquid separator 106.

[0073] The medium tank 105 has a deashing chamber, and the bottom of the deashing chamber is provided with a solid-liquid discharge port 109.

[0074] The stirring mechanism is set on the medium tank 105, and its stirring paddle is located in the deashing chamber. It is used to stir the solid-liquid mixture in the deashing chamber to form a swirling flow. The stirring speed is usually controlled at 200 to 1000 rpm so that the angular velocity of the swirling flow field reaches 20 to 105 rad / s.

[0075] The ultrasonic transducer 102 is installed in the deashing chamber and is used to emit ultrasonic waves to excite cavitation and acoustic flow effects in the solid-liquid mixture in the deashing chamber; the ultrasonic transducer 102 is a piezoelectric transducer that uses the piezoelectric effect of piezoelectric crystals to convert energy.

[0076] The feed inlet of the solid-liquid separator 106 is connected to the solid-liquid outlet 109, and is used to separate the solid-liquid mixture after ultrasonic cyclone coupling treatment; the solid-liquid separator 106 can be a sedimentation separator, a filter separator, a centrifugal separator, or a variety of other types.

[0077] The suspended bed cyclone dryer 2 can use carrier gas to carry pretreated materials to form a cyclone field, and make biomass particles generate self-revolution coupling motion and thus be in a stable suspension state, so as to achieve rapid dehydration and drying and obtain dried materials.

[0078] The suspended bed cyclone pyrolysis device 3 can use carrier gas to carry dry materials to form a cyclone field, and make biomass particles generate self-revolution coupling motion and thus be in a stable suspension state, and achieve rapid pyrolysis at high temperature to obtain pyrolysis oil and gas and pyrolysis char.

[0079] The condensation oil collection device 4 is used to condense and separate pyrolysis oil and gas, and collect high-quality bio-oil.

[0080] Combination Figure 1 and Figure 2 As shown, in some embodiments, there are two or more ultrasonic transducers 102, which are evenly distributed on the bottom surface of the medium tank 105. Typically, the ultrasonic waves emitted by the multiple ultrasonic transducers 102 completely cover the de-ashing chamber to ensure effective de-ashing.

[0081] Specifically, and then combined Figure 1 and Figure 2 As shown, in some embodiments, the stirring mechanism includes a stirring motor 103 and a stirring paddle; the stirring motor 103 is disposed on the upper side of the medium tank 105; the stirring paddle includes a stirring shaft rotatably disposed in the deashing chamber and drivenly connected to the stirring motor 103, and stirring blades disposed on the stirring shaft.

[0082] Specifically, and then combined Figure 1 and Figure 2 As shown, in some embodiments, the ultrasonic vortex device 1 further includes a first feed hopper 101 and a liquid injection pump 104; the first feed hopper 101 is disposed on the medium tank 105, and its outlet is connected to the deashing chamber for adding biomass pellets into the deashing chamber; the liquid injection pump 104 is disposed on the medium tank 105, and its outlet is connected to the deashing chamber for pumping liquid deashing medium into the deashing chamber. The positions of the first feed hopper 101 and the liquid injection pump 104 are usually required to be higher than the liquid level line of the medium tank 105 to prevent backflow of the solid-liquid mixture.

[0083] Combined Figure 1 and Figure 2 As shown, in order to ensure smooth discharge, in some embodiments, the feed inlet of the solid-liquid separator 106 is connected to the solid-liquid discharge outlet 109 through a vertical circular pipe with an inner diameter of not less than 10 mm.

[0084] Combined Figure 1 and Figure 2 As shown, in some embodiments, a split partition plate 107 is provided in the inner cavity of the solid-liquid separator 106. The partition plate 107 divides the inner cavity of the solid-liquid separator 106 into an upper separation chamber and a lower storage bin 108. The solid-liquid separator 106 is provided with a drain port 110 communicating with the separation chamber, and a filter structure is provided at the drain port 110. The split partition plate 107 is easy to open and close and has a guiding function, which facilitates the entry of the separated pre-treated material into the storage bin 108. The storage bin 108 is used to temporarily store the pre-treated material, and it can have various structures, preferably a conical structure that facilitates material discharge.

[0085] Combination Figure 1 and Figure 3 As shown, in some embodiments, the slurry bed cyclone drying device 2 includes a cyclone dryer 203, a first feeding mechanism, and a cyclone separator 207;

[0086] The cyclone dryer 203 includes a dryer body, a first overflow discharge pipe 206, and a first bypass riser pipe 205. The bottom of the dryer body is provided with a dryer bottom port 210 and a first multi-port connector connected to the dryer bottom port 210. The first multi-port connector has a first connection port and a second connection port that are correspondingly connected, and a third connection port that can communicate with the first connection port and / or the second connection port. The third connection port is connected to the dryer bottom port 210. The first overflow discharge pipe 206 is located at the upper end of the dryer body, with its lower part extending into the upper part of the inner cavity of the dryer body, forming a first annular channel with the dryer body. The side of the dryer body is provided with a first tangential feed port 211 that communicates with the first annular channel. The lower end of the first bypass riser pipe 205 is connected to the second connection port, and the upper end of the first bypass riser pipe 205 is connected to the first tangential feed port 211.

[0087] The first feeding mechanism includes a second feeding hopper 209, a first screw feeder 201, and a first blower 202; the inlet of the second feeding hopper 209 is connected to the outlet of the ultrasonic vortex device 1; the inlet of the first screw feeder 201 is connected to the outlet of the second feeding hopper 209, and the outlet of the first screw feeder 201 is connected to a first connecting port; the outlet of the first blower 202 is connected to the feeding channel of the first screw feeder 201 or to the first connecting port.

[0088] The hydrocyclone separator 207 has a second tangential feed inlet, an overflow exhaust pipe 208 and a dry material outlet. The second tangential feed inlet is connected to the outlet of the first overflow discharge pipe 206, and a receiving bin 204 is connected to the dry material outlet.

[0089] The working process of the above-mentioned suspended bed cyclone dryer 2 is as follows: the pre-treated material enters the first screw feeder 201 from the second feed hopper 209 and is conveyed to the first connection port by the first screw feeder 201. Under the action of the carrier gas introduced by the first blower 202, the pre-treated material forms a first material flow, which is then divided in the first multi-port connector. Part of the first material flow enters the cyclone dryer 203 from the dryer bottom port 210, and the other part of the first material flow rises along the first bypass riser pipe 205 and enters the cyclone dryer 203 from the first tangential feed port 211 to form a cyclone field, and causes the biomass pellets to generate a self-revolution coupling motion. The material is in a stable suspended state to achieve rapid dehydration and drying. By adjusting the flow rate of the first bypass riser 205 and / or the air volume of the first blower 202, the suspension height of the pre-treated material in the cyclone dryer 203 can be adjusted, and deep dehydration can be achieved. When the moisture content of the pre-treated material is less than 10%, the biomass pellets cannot maintain a suspended state due to the change in specific gravity. They will be driven by the rising airflow in the middle of the cyclone field and enter the cyclone separator 207 through the first overflow outlet pipe 206. Then, under the centrifugal separation action of the cyclone separator 207, gas-solid separation is achieved, and the dried material is collected by the receiving bin 204.

[0090] Combined Figure 1 and Figure 3 As shown, in some embodiments, the dryer body is preferably cylindrical (zero cone angle). This allows for well-controlled suspension of the pretreated material, resulting in a higher dehydration rate, and effectively avoids short-circuit flow.

[0091] To facilitate operator monitoring of the suspension state of the pretreated materials, an observation window is provided on the dryer body in some embodiments. To improve visibility and make the cyclone dryer 203 more suitable for laboratory use, in some embodiments, the entire cyclone dryer 203 is made of a transparent material. The transparent material is preferably acrylic, which has high strength and transparency.

[0092] Combination Figure 1 and Figure 4 As shown, in some embodiments, the slurry bed cyclone pyrolysis device 3 includes a cyclone pyrolyzer 304, a second feeding mechanism, and a carbon storage bin 311;

[0093] The cyclone pyrolyzer 304 includes a pyrolyzer body, a second overflow discharge pipe 310, a second bypass riser pipe 308, and a pyrolysis heater 305. The bottom of the pyrolyzer body is provided with a pyrolyzer bottom port 307, and a second multi-port connector connected to the pyrolyzer bottom port 307. The second multi-port connector has a fifth and a sixth port correspondingly connected, a seventh port that can communicate with the fifth and / or the sixth port, and an eighth port correspondingly connected to the seventh port. The seventh port is connected to the pyrolyzer bottom port 307. The two overflow discharge pipes 310 are located at the upper end of the pyrolyzer body, with their lower parts extending into the upper part of the inner cavity of the pyrolyzer body and forming a second annular channel with the pyrolyzer body; the side of the pyrolyzer body is provided with a third tangential feed port 309 that communicates with the second annular channel; the lower end of the second bypass riser pipe 308 is connected to the sixth connection port, and the upper end of the second bypass riser pipe 308 is connected to the third tangential feed port 309; the pyrolysis heater 305 is located on the pyrolyzer body and is used to heat the material inside the pyrolyzer body;

[0094] The second feeding mechanism includes a third feed hopper 306, a second screw feeder 301, a second blower 302, and a gas preheater 303; the feed inlet of the third feed hopper 306 is connected to the discharge outlet of the cyclone dryer 2; the feed inlet of the second screw feeder 301 is connected to the discharge outlet of the third feed hopper 306, and the discharge outlet of the second screw feeder 301 is connected to the fifth connection port; the second blower 302 is connected to the feeding channel of the first screw feeder 201 or to the fifth connection port through the gas preheater 303;

[0095] The feed inlet of the carbon storage bin 311 is connected to the eighth connection port.

[0096] The working process of the above-mentioned suspended bed cyclone pyrolysis device 3 is as follows: the dried material enters the second screw feeder 301 from the third feed hopper 306 and is conveyed to the fifth connection port by the second screw feeder 301. At the same time, the carrier gas blown out by the second blower 302 is preheated by the gas preheater 303 and mixed with the dried material to form a second material flow. The second material flow is divided in the second multi-port connector. Part of the second material flow enters the cyclone pyrolysis unit 304 from the bottom port 307 of the pyrolysis unit, and the other part of the second material flow rises along the second bypass riser pipe 308 and enters the cyclone pyrolysis unit 304 from the third tangential feed port 309 to form a cyclone field. The biomass pellets are made to undergo self-revolutionary coupling motion and thus be in a stable suspension state. By adjusting the flow rate of the second bypass riser 308 and / or the air volume of the second blower 302, the suspension height of the dried material in the cyclone pyrolyzer 304 can be adjusted to accelerate heat and mass transfer. Then, under the heating action of the pyrolysis heater 305, the material is rapidly pyrolyzed into pyrolysis oil and gas and pyrolysis char. The pyrolysis oil and gas will flow out through the second overflow outlet pipe 310 under the drive of the rising airflow in the middle of the cyclone field. Then, by slowly reducing the carrier gas flow rate, the pyrolysis char can no longer maintain a suspension state and enters the char storage bin 311 from the eighth connection port to be collected.

[0097] Combined Figure 1 and Figure 4 As shown, in some embodiments, the pyrolyzer body is preferably cylindrical (zero cone angle). This allows for well-controlled suspension of the dried material, resulting in higher pyrolysis efficiency, and effectively avoids short-circuit flow.

[0098] To facilitate operator monitoring of the suspension state of the dried material, in some embodiments, the pyrolyzer body is provided with an observation window. To improve visibility and make the cyclone pyrolyzer 304 more suitable for laboratory use, in some embodiments, the entire cyclone pyrolyzer 304 is made of a high-temperature resistant transparent material. The high-temperature resistant transparent material is preferably high-temperature resistant quartz.

[0099] Combination Figure 1 and Figure 5As shown, in some embodiments, the condensation and oil collection device 4 includes a condenser 401, a sprayer 402, and a product collection tank 403. The inner cavity of the condenser 401 is a condensation chamber. The condenser 401 is provided with a pyrolysis oil gas inlet pipe 405 communicating with the bottom of the condensation chamber, a tail gas outlet 404 communicating with the top of the condensation chamber, and a bio-oil outlet communicating with the bottom of the condensation chamber. The inlet of the pyrolysis oil gas inlet pipe 405 is connected to the outlet of the slurry bed cyclone pyrolysis device 3. The sprayer 402 is disposed on the inner top surface of the condenser 401, with its nozzle facing the condensation chamber. The inlet of the product collection tank 403 is connected to the bio-oil outlet. A heat exchange structure is provided in the condensation chamber, preferably an inner-liner type multi-channel parallel pipe, for continuous heat exchange between the circulating condensate and the pyrolysis oil gas. The tail gas outlet 404 is used to discharge the separated non-condensable pyrolysis gas, which can be used as fuel for the pyrolysis heater 305. The sprayer 402 is used to spray organic solvent into the condensation chamber to efficiently collect and separate high-quality bio-oil; the sprayer 402 can be of various types, preferably a sprayer 402 with multi-directional high-pressure nozzles to ensure efficient and stable operation.

[0100] Example 1

[0101] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention, using high-ash materials as raw materials, comprises the following steps:

[0102] S1: The biomass raw material is a blend of 70% corn straw, 10% wheat straw, and 20% rice straw; the biomass is crushed into particles with an average diameter of <5mm; the crushed biomass enters the medium tank 105 through the first feed hopper 101, and water is pumped into the medium tank 105 through the injection pump 104 to form a solid-liquid mixture. The stirring speed is controlled at 200rpm, the ultrasonic frequency is 80kHz, and the ultrasonic power density is 5w / cm³. 3 After being treated by ultrasonic vortex coupling for 3 hours, the solid-liquid mixture is introduced into the solid-liquid separator 106 for solid-liquid separation. After separation, wet biomass is obtained and the isolation plate 107 is opened to let it fall into the storage bin 108 to obtain pretreated material.

[0103] S2: The pre-treated material enters the first screw feeder 201 from the second feed hopper 209 and is conveyed to the first connection port. Under the action of the airflow introduced by the first blower 202, the pre-treated material forms the first material flow, and the air-to-solid ratio of the air to the pre-treated material is controlled at 14m. 3 / kg; The first material flow is split in the first multi-port connector. Part of the first material flow enters the cyclone dryer 203 from the bottom port 210 of the dryer, and the other part of the first material flow rises along the first bypass riser pipe 205 and enters the cyclone dryer 203 from the first tangential feed port 211 to form a cyclone field. The biomass particles generate self-revolution coupling motion and thus are in a stable suspension state, achieving deep dehydration. When the moisture content of the pretreated material is less than 10%, the biomass particles are driven by the rising airflow in the middle of the cyclone field and enter the cyclone separator 207 through the first overflow discharge pipe 206. Then, under the centrifugal separation action of the cyclone separator 207, gas-solid separation is achieved, and the dried material is obtained and collected by the receiving bin 204. The separated gas is discharged from the overflow exhaust pipe 208.

[0104] S3: The dried material enters the second screw feeder 301 from the third feed hopper 306 and is conveyed to the fifth connection port by the second screw feeder 301. At the same time, the nitrogen blown out by the second blower 302 is preheated by the gas preheater 303 and mixed with the dried material to form a second material flow. The gas-solid ratio of nitrogen to dried material is controlled at 50m. 3 / kg; The second material flow is split in the second multi-port connector. Part of the second material flow enters the cyclone pyrolyzer 304 from the bottom port 307 of the pyrolyzer, and the other part of the second material flow rises along the second bypass riser pipe 308 and enters the cyclone pyrolyzer 304 from the third tangential feed port 309 to form a cyclone field. The biomass particles generate self-revolution coupling motion and thus enter a stable suspension state. Then, under the heating action of the pyrolysis heater 305, they are rapidly pyrolyzed into pyrolysis oil and gas and pyrolysis char. The pyrolysis temperature is 550℃ and the pyrolysis time is 35min. The pyrolysis oil and gas flows out along the second overflow outlet pipe 310 under the drive of the rising airflow in the middle of the cyclone field. Then, by slowly reducing the nitrogen flow rate, the pyrolysis char enters the char storage bin 311 from the eighth connector and is collected.

[0105] S4: The pyrolysis oil gas first enters the condenser 401 through the pyrolysis oil gas inlet pipe 405, where it exchanges heat with the condenser in the condenser tube, causing the pyrolysis oil gas to condense and separate into non-condensable pyrolysis gas and condensed bio-oil; the condenser is a mixed solution of ethylene glycol and water, and the condensation temperature is -15℃.

[0106] S5: Turn on the sprayer 402 to spray organic solvent onto the condensed bio-oil. The bio-oil dissolved in the organic solvent flows into the product collection tank 403 to obtain high-quality bio-oil. Ethanol is selected as the organic solvent. The organic solvent spraying process is an intermittent high-pressure spraying process.

[0107] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0108] Example 2

[0109] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention are used to prepare high-quality bio-oil from high-ash materials.

[0110] The steps in this embodiment are the same as those in Embodiment 1, except that: in S1, the stirring speed is 600 rpm, the ultrasonic frequency is 50 kHz, and the ultrasonic power density is 2 W / cm². 3 The ultrasonic vortex coupling treatment time was 0.5 h; the gas-solid ratio of air to pretreated material in S2 was 12 m³ / s. 3 / kg; the pyrolysis temperature in S3 is 500℃, the pyrolysis time is 15min, and the gas-solid ratio of nitrogen to dried material is 35m. 3 / kg.

[0111] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0112] Example 3

[0113] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention are used to prepare high-quality bio-oil from high-ash materials.

[0114] The steps in this embodiment are the same as those in Embodiment 1, except that: in S1, the stirring speed is 1000 rpm, the ultrasonic frequency is 20 kHz, and the ultrasonic power density is 2.5 W / cm³. 3 The ultrasonic vortex coupling treatment time was 2 hours; the gas-solid ratio of air to pretreated material in S2 was 10 m³ / s. 3 / kg; the pyrolysis temperature in S3 is 600℃, the pyrolysis time is 25min, and the gas-solid ratio of nitrogen to dried material is 30m. 3 / kg.

[0115] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0116] Example 4

[0117] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention are used to prepare high-quality bio-oil from high-ash materials.

[0118] The steps in this embodiment are the same as those in Embodiment 1, except that: in S1, the stirring speed is 800 rpm, the ultrasonic frequency is 60 kHz, and the ultrasonic power density is 1 W / cm³. 3 The ultrasonic vortex coupling treatment time was 1 hour; the gas-solid ratio of air to pretreated material in S2 was 8 m³ / s. 3 / kg; the pyrolysis temperature in S3 is 450℃, the pyrolysis time is 40min, and the gas-solid ratio of nitrogen to dried material is 40m.3 / kg.

[0119] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0120] Example 5

[0121] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention are used to prepare high-quality bio-oil from high-ash materials.

[0122] The steps in this embodiment are the same as those in Embodiment 1, except that: in S1, the stirring speed is 400 rpm and the ultrasonic power density is 4 W / cm³. 3 The ultrasonic vortex coupling treatment time was 2 hours; the gas-solid ratio of air to pretreated material in S2 was 16 m³ / s. 3 / kg; the pyrolysis time in S3 is 30 min, and the gas-solid ratio of nitrogen to dried material is 15m. 3 / kg.

[0123] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0124] Example 6

[0125] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention are used to prepare high-quality bio-oil from high-ash materials.

[0126] The steps in this embodiment are the same as those in Embodiment 1, except that: in S1, the stirring speed is 500 rpm, the ultrasonic frequency is 50 kHz, and the ultrasonic power density is 3.5 W / cm³. 3 The gas-solid ratio of air to pretreated materials in S2 is 12m. 3 / kg; the pyrolysis temperature in S3 is 500℃, the pyrolysis time is 20min, and the gas-solid ratio of nitrogen to dried material is 20m. 3 / kg.

[0127] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0128] Example 7

[0129] The method and system for preparing high-quality bio-oil using biomass pyrolysis provided by this invention are used to prepare high-quality bio-oil from high-ash materials.

[0130] The steps in this embodiment are the same as those in Embodiment 1, except that: in S1, the stirring speed is 700 rpm, the ultrasonic frequency is 70 kHz, and the ultrasonic power density is 3 W / cm². 3The ultrasonic vortex coupling treatment time was 2 hours; the gas-solid ratio of air to pretreated material in S2 was 8 m³ / s. 3 / kg; the pyrolysis temperature in S3 is 600℃, the pyrolysis time is 10min, and the gas-solid ratio of nitrogen to dried material is 10m. 3 / kg.

[0131] The ash removal rate and bio-oil yield of this embodiment are shown in Table 1, and the composition distribution of high-quality bio-oil is shown in Table 2.

[0132] Comparative Example 1

[0133] The steps in this comparative example are the same as those in Example 1, except that step S1 is not involved, and un-ashed biomass is directly used for subsequent oil production.

[0134] The ash removal rate and bio-oil yield of this comparative example are shown in Table 1, and the bio-oil composition distribution is shown in Table 2.

[0135] Comparative Example 2

[0136] This study utilizes existing fixed-bed pyrolysis methods to produce high-quality bio-oil from high-ash materials. The apparatus used is a conventional fixed-bed pyrolysis reactor, the structure of which can be found in the literature (P. Wei, G. Chen, A. Zhang, H. Deng, X. Wen, F. Wang, Study on the pyrolysis and combustion characteristics of municipal solid waste in a fixed bed, Journal of Material Cycles and Waste Management, Volume 26, pages 1727–1735, (2024).).

[0137] The raw materials used were the same as in Example 1. The steps for preparing bio-oil were as follows: First, untreated biomass feedstock was placed in a fixed-bed pyrolysis reactor, and the reaction parameters were set as follows: pyrolysis temperature 550℃, residence time 30 min, and gas-to-solid ratio 15 m³ / s. 3 / kg. After the reaction is complete, the bio-oil is collected and its components are analyzed.

[0138] The bio-oil yield of this comparative example is shown in Table 1, and the bio-oil composition distribution is shown in Table 2.

[0139] Table 1: Biomass ash removal rate and bio-oil yield of each example and comparative example

[0140] Ash removal rate Bio-oil yield Example 1 40％ 52％ Example 2 41％ 50％ Example 3 43％ 49％ Example 4 45％ 46％ Example 5 55％ 51％ Example 6 53％ 54％ Example 7 50％ 49％ Comparative Example 1 0％ 42％ Comparative Example 2 0％ 37％ .

[0141] Table 2: Distribution of Bio-oil Components in Each Example and Comparative Example

[0142]

[0143]

[0144] As can be seen from Tables 1 and 2, the method and system for preparing high-quality bio-oil by biomass pyrolysis provided by this invention combines ultrasonic cyclone deashing technology with suspended bed cyclone drying and pyrolysis technology, achieving a high yield of 46% to 52% and high quality (0.6% to 1.5% nitrogen-containing impurities and 35.5% to 40.5% oxygen content) of bio-oil.

[0145] Compared with Comparative Example 1, the introduction of ultrasonic cyclone deashing technology can achieve a high ash removal rate of 40% to 55% for biomass. Furthermore, by controlling the cyclone drying and cyclone pyrolysis processes, compared with Comparative Example 1, the nitrogen impurities in the bio-oil components are reduced by at least 42.3%, and the oxygen content is reduced by at least 21.1%, effectively reducing the nitrogen impurities and oxygen content in the bio-oil and greatly improving its quality.

[0146] Compared with conventional fixed-bed pyrolysis (specifically, Comparative Example 5 and Comparative Example 2), it can be seen that the method and system for preparing high-quality bio-oil by biomass pyrolysis provided by the present invention can achieve a 37.8% increase in bio-oil yield and a 74.2% and 31.9% reduction in nitrogen impurities and oxygen content in bio-oil, respectively.

[0147] Furthermore, compared with traditional chemical, biological, and thermal pretreatment methods, this invention can remove ash from biomass under a relatively mild environment and avoid the loss of biomass components. The low-consumption and environmentally friendly ultrasonic cyclone deashing technology not only alleviates equipment corrosion and pipeline blockage problems in the biomass pyrolysis process but also effectively improves the quality of bio-oil. Combining the advantages of ultrasonic cyclone drying and suspended bed cyclone drying and pyrolysis, it highlights a green, low-consumption, and efficient pathway for preparing bio-oil from biomass.

[0148] This document presents a description of various embodiments of the invention for illustrative purposes only and is not intended to be exhaustive or 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 has been chosen to best explain the principles, practical applications, or technological advancements of the embodiments, or to enable others skilled in the art to understand the embodiments disclosed herein, compared to technologies found in the market.

[0149] In this document, various embodiments of the invention may be presented in the form of a scope. It should be understood that the scope description is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention. Therefore, the scope description should be considered to specifically disclose all possible sub-scopes and individual numerical values ​​within that scope. For example, a description of a scope such as 1 to 6 should be considered to specifically disclose sub-scopes, such as 1 to 3, 1 to 4, 1 to 5, 2 to 4, 2 to 6, 3 to 6, etc., and individual numerical values ​​within that scope, such as 1, 2, 3, 4, 5, 6, regardless of the width of the scope.

[0150] It should be understood that, for clarity, certain features of the invention described in the context of a single embodiment may also be provided in combination in a single embodiment. Conversely, for brevity, various features of the invention described in the context of a single embodiment may also be provided individually or in any suitable sub-combination, or, where appropriate, in any other described embodiment of the invention. Unless the embodiment does not function without those features, certain features described in the context of various embodiments are not considered essential features of those embodiments.

[0151] All publications, patents, and patent applications mentioned herein are incorporated herein by reference in their entirety, as if each individual publication, patent, or patent application were specifically and individually indicated as incorporated herein by reference. Furthermore, any reference or designation of any reference herein should not be construed as an admission that such reference is prior art to the invention. With regard to the use of section headings, section headings should not be construed as necessary limitations.

Claims

1. A method for preparing high-quality bio-oil using biomass pyrolysis, comprising a pretreatment step, a drying step, a pyrolysis step, and an oil collection step performed sequentially; characterized in that: The pretreatment steps are as follows: After the biomass is crushed, it is added to a container together with the liquid deashing medium. The ash in the biomass is removed by ultrasonic cyclone coupling treatment. After deashing, the pretreated material is obtained by solid-liquid separation. The drying step is as follows: the pretreated material is subjected to controlled suspension cyclone drying to reduce its moisture content to below 10% to obtain the dried material; The pyrolysis steps are as follows: the dried material is subjected to controlled suspension cyclone pyrolysis to obtain pyrolysis oil and gas and pyrolysis char. The oil recovery process involves: subjecting the pyrolysis oil and gas to low-temperature condensation treatment to separate non-condensable pyrolysis gas and high-quality bio-oil; the yield of high-quality bio-oil is ≥40%, and its nitrogen content is ≤1.5% and oxygen content is ≤40.5%.

2. The method for preparing high-quality bio-oil using biomass pyrolysis according to claim 1, characterized in that: Biomass refers to waste biomass, which includes at least one of the following: corn stalks, wheat stalks, rice stalks, distiller's grains, rice husks, sludge, sawdust, walnut shells, and livestock manure.

3. The method for preparing high-quality bio-oil by biomass pyrolysis according to claim 1 or 2, characterized in that: Ultrasonic vortex coupling treatment utilizes the dynamic superposition of the cavitation effect of ultrasound and the centrifugal force field of the vortex field to treat the solid-liquid mixture of biomass particles and liquid deashing medium, thereby removing ash from the biomass. The ultrasonic vortex coupling treatment time is 0.5–4 h, the angular velocity of the vortex field is 20–105 rad / s, the frequency of the ultrasound is 20–80 kHz, and the power density of the ultrasound is 1–5 W / cm³. 3 ; And / or, controlled suspension cyclone drying involves using a carrier gas to carry the pretreated material to form a cyclone field, causing the biomass particles to undergo self-rotational coupled motion and thus be in a stable suspension state, thereby achieving rapid dehydration and drying; during the controlled suspension cyclone drying process: the temperature is room temperature, the carrier gas used is air, and the gas-solid ratio of air to pretreated material is 8–16 m³ / s. 3 / kg; And / or, controlled suspension cyclone pyrolysis treatment involves: using a carrier gas to carry the dried material to form a cyclone field, causing the biomass particles to undergo self-rotational coupled motion and thus be in a stable suspension state, achieving rapid pyrolysis at high temperature; during the controlled suspension cyclone pyrolysis process: the pyrolysis temperature is 450–600℃, the pyrolysis time is 10–40 min, the carrier gas used is nitrogen, and the gas-solid ratio of nitrogen to the dried material is 10–50 m³ / s. 3 / kg; And / or, low-temperature condensation treatment is: under the condition of -25 to -15℃, the pyrolysis oil and gas are condensed and separated into non-condensable pyrolysis gas and high-quality bio-oil.

4. The method for preparing high-quality bio-oil by biomass pyrolysis according to claim 3, characterized in that: In the low-temperature condensation process, the condenser exchanges heat with the pyrolysis oil and gas to cause them to condense and separate. The oil collection process also includes collecting and separating high-quality bio-oil using an organic solvent spraying process.

5. A system for preparing high-quality bio-oil by biomass pyrolysis, for implementing the method for preparing high-quality bio-oil by biomass pyrolysis as described in any one of claims 1 to 4, comprising an ultrasonic cyclone device (1), a suspended bed cyclone drying device (2), a suspended bed cyclone pyrolysis device (3), and a condensation and oil collection device (4); Its features are: The ultrasonic cyclone device (1) is used to perform ultrasonic cyclone coupling treatment on the solid-liquid mixture of biomass particles and liquid deashing medium to remove ash from the biomass and obtain pretreated material; the ultrasonic cyclone device (1) includes a medium tank (105), a stirring mechanism, an ultrasonic transducer (102) and a solid-liquid separator (106). The medium tank (105) has a deashing chamber, and the bottom of the deashing chamber is provided with a solid-liquid discharge port (109). The stirring mechanism is set on the medium tank (105), and its stirring paddle is located in the deashing chamber to stir the solid-liquid mixture in the deashing chamber to form a swirling flow; The ultrasonic transducer (102) is installed in the deashing chamber and is used to emit ultrasonic waves to excite cavitation and acoustic flow effects in the solid-liquid mixture in the deashing chamber. The feed inlet of the solid-liquid separator (106) is connected to the solid-liquid outlet (109) for solid-liquid separation of the solid-liquid mixture after ultrasonic cyclone coupling treatment; The suspended bed cyclone drying device (2) can use carrier gas to carry pretreated materials to form a cyclone field and make biomass particles generate self-revolution coupling motion and thus be in a stable suspension state, so as to achieve rapid dehydration and drying and obtain dried materials. The suspended bed cyclone pyrolysis device (3) can use carrier gas to carry dry materials to form a cyclone field, and make biomass particles generate self-revolution coupling motion and thus be in a stable suspension state, and achieve rapid pyrolysis at high temperature to obtain pyrolysis oil and gas and pyrolysis carbon; The condensation and oil collection device (4) is used to condense and separate pyrolysis oil and gas, and collect high-quality bio-oil.

6. The system for preparing high-quality bio-oil by biomass pyrolysis according to claim 5, characterized in that: The ultrasonic cyclone device (1) further includes a first feed hopper (101) and a liquid injection pump (104); The first feed hopper (101) is set on the medium tank (105), and its outlet is connected to the deashing chamber for adding biomass pellets into the deashing chamber; The injection pump (104) is installed on the medium tank (105), and its outlet is connected to the deashing chamber for pumping liquid deashing medium into the deashing chamber.

7. The system for preparing high-quality bio-oil by biomass pyrolysis according to claim 6, characterized in that: The solid-liquid separator (106) has a split partition plate (107) in its inner cavity, which divides the inner cavity of the solid-liquid separator (106) into an upper separation chamber and a lower storage hopper (108). The solid-liquid separator (106) has a drain port (110) that communicates with the separation chamber, and a filter structure is provided at the drain port (110).

8. The system for preparing high-quality bio-oil by biomass pyrolysis according to claim 5, characterized in that: The suspended bed cyclone drying device (2) includes a cyclone dryer (203), a first feeding mechanism, and a cyclone separator (207); The cyclone dryer (203) includes a dryer body, a first overflow outlet pipe (206), and a first bypass riser pipe (205); the bottom of the dryer body is provided with a dryer bottom port (210) and a first multi-port connector connected to the dryer bottom port (210); the first multi-port connector has a first connection port and a second connection port that are connected to each other, and a third connection port that can be connected to the first connection port and / or the second connection port; the third connection port is connected to the dryer bottom port (210); the first overflow outlet pipe (206) is located at the upper end of the dryer body, and its lower part extends into the upper part of the inner cavity of the dryer body and forms a first annular channel with the dryer body; the side of the dryer body is provided with a first tangential feed port (211) that is connected to the first annular channel; the lower end of the first bypass riser pipe (205) is connected to the second connection port, and the upper end of the first bypass riser pipe (205) is connected to the first tangential feed port (211); The first feeding mechanism includes a second feed hopper (209), a first screw feeder (201), and a first blower (202); the feed inlet of the second feed hopper (209) is connected to the discharge outlet of the ultrasonic vortex device (1); the feed inlet of the first screw feeder (201) is connected to the discharge outlet of the second feed hopper (209), and the discharge outlet of the first screw feeder (201) is connected to a first connection port; the air outlet of the first blower (202) is connected to the feeding channel of the first screw feeder (201) or to the first connection port; The cyclone separator (207) has a second tangential feed inlet, an overflow exhaust pipe (208) and a dry material outlet. The second tangential feed inlet is connected to the outlet of the first overflow discharge pipe (206), and a receiving bin (204) is connected to the dry material outlet.

9. The system for preparing high-quality bio-oil by biomass pyrolysis according to claim 5, characterized in that: The suspended bed cyclone pyrolysis device (3) includes a cyclone pyrolyzer (304), a second feeding mechanism, and a carbon storage bin (311); The cyclone pyrolyzer (304) includes a pyrolyzer body, a second overflow outlet pipe (310), a second bypass riser pipe (308), and a pyrolysis heater (305); the bottom of the pyrolyzer body is provided with a pyrolyzer bottom port (307), and a second multi-port connector connected to the pyrolyzer bottom port (307); the second multi-port connector has a fifth and a sixth port correspondingly connected, a seventh port that can be connected to the fifth and / or the sixth port, and an eighth port correspondingly connected to the seventh port; the seventh port is connected to the pyrolyzer bottom port (307); The second overflow outlet pipe (310) is located at the upper end of the pyrolyzer body, with its lower part extending into the upper part of the inner cavity of the pyrolyzer body and forming a second annular channel with the pyrolyzer body; the side of the pyrolyzer body is provided with a third tangential feed port (309) that communicates with the second annular channel; the lower end of the second bypass riser pipe (308) is connected to the sixth connection port, and the upper end of the second bypass riser pipe (308) is connected to the third tangential feed port (309); the pyrolysis heater (305) is located on the pyrolyzer body and is used to heat the material inside the pyrolyzer body; The second feeding mechanism includes a third feed hopper (306), a second screw feeder (301), a second blower (302), and a gas preheater (303); the feed inlet of the third feed hopper (306) is connected to the discharge outlet of the cyclone dryer (2); the feed inlet of the second screw feeder (301) is connected to the discharge outlet of the third feed hopper (306), and the discharge outlet of the second screw feeder (301) is connected to a fifth connection port; the second blower (302) is connected to the feeding channel of the first screw feeder (201) or to the fifth connection port through the gas preheater (303); The feed inlet of the carbon storage bin (311) is connected to the eighth connection port.

10. The system for preparing high-quality bio-oil by biomass pyrolysis according to claim 5, characterized in that: The condensation and oil collection device (4) includes a condenser (401), a sprayer (402), and a product collection tank (403); The inner cavity of the condenser (401) is a condensation cavity. The condenser (401) is provided with a pyrolysis oil and gas inlet pipe (405) communicating with the bottom of the condensation cavity, a tail gas outlet (404) communicating with the top of the condensation cavity, and a bio-oil outlet communicating with the bottom of the condensation cavity. The inlet of the pyrolysis oil and gas inlet pipe (405) is connected to the outlet of the slurry bed cyclone pyrolysis device (3). The sprayer (402) is disposed on the inner top surface of the condenser (401), with its nozzle facing the condensation chamber; The inlet of the product collection tank (403) is connected to the bio-oil outlet.

Images