Preparation method and device of high-purity furfural

Abstract

This invention belongs to the field of furfural preparation technology, specifically a method and apparatus for preparing high-purity furfural. The apparatus includes a horizontal reactor, a drive mechanism, a coking mechanism, a steam distribution mechanism, a waste heat recovery mechanism, and a discharge mechanism. Through the coordination of the coking mechanism, steam distribution mechanism, and waste heat recovery mechanism, the invention solves the defects of existing furfural preparation devices, such as severe coking, low steam utilization, high energy consumption, insufficient furfural purity, and difficulty in recycling residues. It achieves continuous and efficient furfural preparation, significantly improved product purity, and reduced production energy consumption, balancing production efficiency, product quality, and energy conservation and environmental protection. The coordination between the coking mechanism, steam distribution mechanism, waste heat recovery mechanism, and discharge mechanism effectively improves production stability and is suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the field of furfural preparation technology, specifically a method and apparatus for preparing high-purity furfural. Background Technology

[0002] Patent application number CN202421211479.9 discloses a furfural biomass raw material processing device, including a cooking kettle, a catalytic adjustment mechanism, a cooking mechanism, an extraction mechanism, and a waste carbonization mechanism. A raw liquid tank is fixedly located at the front of one side of the cooking kettle, and a water tank is fixedly located at the rear of one side of the cooking kettle. An injection pipe is connected to one side of the cooking kettle. A first water pump is connected to the other side of the raw liquid tank and the water tank. A first on / off valve is symmetrically connected to one side of the injection pipe. An electric telescopic rod is fixedly located at the upper end of the injection pipe, and a sealing plug is fixedly located at the telescopic end of the electric telescopic rod. A cooking mechanism is located inside the cooking kettle, and an extraction mechanism is connected below the cooking kettle. A waste carbonization mechanism is located below the cooking kettle. This invention adjusts the concentration by precisely delivering catalyst raw liquid and water into the injection pipe. The electric telescopic rod retracts, causing the sealing plug to rise, precisely controlling the amount of catalyst added to optimize reaction conditions. The byproduct biochar is obtained by igniting the gas supplied by the gas tank next to the burner using an igniter.

[0003] In existing technologies, including the aforementioned patents, furfural preparation mostly employs vertical batch hydrolysis reactors, which have the following main drawbacks: First, the coking problem is serious. During the hydrolysis process, biomass raw materials and catalysts are prone to side reactions under high temperature and high pressure. The generated coke will quickly adhere to the inner wall of the reactor, steam channel and heat exchange surface. This will not only block the steam flow path and reduce the heat exchange efficiency, but also cause uneven mixing of materials inside the unit. Frequent shutdowns are required for manual cleaning of the reactor, which not only increases maintenance costs, but also interrupts the continuous production process, affecting the continuity of production and the stability of production capacity. Second, the steam distribution is uneven. Steam is usually delivered by direct injection through a single pipe or by spraying with fixed nozzles. The steam cannot achieve uniform coverage of the material in the reactor, resulting in local overheating and underheating of the material. Overheated areas will further aggravate coking, while underheated areas will reduce the efficiency of hydrolysis reaction. At the same time, the unutilized steam will be lost with the exhaust gas or residue, resulting in low steam utilization and high energy and water consumption, which does not meet the requirements of energy-saving production. Third, the waste heat cannot be effectively recovered. The furfural hydrolysis reaction requires maintaining a high temperature environment of 170-190℃. During the reaction, the heat dissipation from the reactor wall, the waste heat from the solid residue after the reaction, and the waste heat from the gas discharge are all directly emitted without effective recovery and utilization. This not only causes a large amount of energy waste, but also leads to excessively high ambient temperature in the production workshop, increases workshop cooling costs, and further increases overall production energy consumption.

[0004] The three defects mentioned above are interconnected and influence each other, severely restricting the efficiency of furfural preparation. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus for preparing high-purity furfural, so as to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A high-purity furfural preparation apparatus includes a horizontal vessel, a drive mechanism, a coke breaking mechanism, a steam distribution mechanism, a waste heat recovery mechanism, and a discharge mechanism. The coke breaking mechanism includes a main shaft and a coke breaking blade assembly. The inner cavity of the main shaft is provided with a channel for steam flow and is arranged along the axial direction of the horizontal vessel. The coke breaking blade assembly is provided with wear-resistant scrapers that fit against the inner wall of the horizontal vessel. The steam distribution mechanism includes a main steam pipe connected to the inner cavity of the main shaft and multiple rotating nozzles. The waste heat recovery mechanism includes a jacket wrapped around the outside of the horizontal vessel. The jacket is divided into three independent heat exchange chambers along the axial direction: a preheating section, a reaction section, and a heat preservation section, and is connected in series with a boiler feedwater preheating pipeline.

[0007] Preferably, the horizontal reactor body is provided with a biomass inlet and a catalyst inlet at the top, a solid phase outlet at the bottom of the other end, and a gas phase outlet at the top.

[0008] Preferably, the driving mechanism includes two driving motors, both of which are fixed on the side wall of the horizontal vessel, and the output ends of the two driving motors are respectively connected to the main shaft and the discharge mechanism.

[0009] Preferably, the coke breaking knife assembly further includes a ventilation rod, multiple spirally arranged spiral scraper rods, and multiple feeding rods located inside the spirally arranged spiral scraper rods. The feeding rods and spiral scraper rods are all connected to the outer wall of the main shaft through the ventilation rod. Multiple ventilation rods are provided and are connected to the inner cavity of the main shaft. The other end of the ventilation rod is provided with multiple fan-shaped atomizing high-temperature nozzles. Multiple wear-resistant scrapers are provided on the outer wall of the spiral scraper rod and are arranged sequentially according to the spiral path of the spiral scraper rod. The front end of the wear-resistant scraper head is stepped.

[0010] Preferably, one end of the main steam pipe is connected to a high-temperature steam conveying pipe, which is located at one end of the horizontal vessel. The outer wall of the main steam pipe is provided with multiple air holes communicating with the rotating nozzles, and the multiple rotating nozzles are rotatably connected to the outer wall of the main shaft.

[0011] Preferably, the discharge mechanism includes a conveying chamber, a twin screw, and a neutralization spray assembly. The inlet end of the conveying chamber is sealed and connected to the solid phase outlet of the horizontal reactor. The twin screw is horizontally arranged in the conveying chamber, and its surface is coated with a tungsten carbide wear-resistant and corrosion-resistant coating. The twin screw is connected to the output end of a drive motor adjacent to the drive mechanism. The neutralization spray assembly is located at the top of the conveying chamber, and the spraying direction is towards the conveying working surface of the twin screw.

[0012] Preferably, the top of the preheating section is connected to a heating pipe, and the other end of the heating pipe is connected to two preheating ring pipes located in the jacket. The other ends of the two preheating ring pipes are connected to a reaction pipe and a first external guide pipe. The reaction pipe is located in the reaction section, and the other end of the reaction pipe is connected to a heat preservation pipe and two second external guide pipes. The other end of the second external guide pipe is connected to the other end of the horizontal vessel and communicates with the inner cavity of the horizontal vessel. The heat preservation pipe is located in the heat preservation section. Both the first and second external guide pipes are equipped with electromagnetic delivery pumps, and both ends of the electromagnetic delivery pumps are equipped with gas filters.

[0013] A method for preparing high-purity furfural, using the apparatus for preparing high-purity furfural as described in any of the preceding claims, includes the following steps: S1: Raw material pretreatment: Crush corn cobs, sugarcane bagasse or straw biomass raw materials to 20-40 mesh, and mix them evenly with 1.5%-3% by mass of dilute sulfuric acid catalyst at a solid-liquid ratio of 1:3-1:5 to obtain a mixture. S2: After feeding, start the device to continuously feed the mixed material into the inner cavity of the horizontal reactor body through the biomass feed port at one end of the horizontal reactor body. Start the drive mechanism to drive the main shaft, coke breaking knife group, spiral scraper and wear-resistant scraper to rotate at a speed of 5-15r / min. At the same time, open the high temperature steam delivery pipeline to send high temperature steam into the main steam pipe, and distribute it through the inner cavity of the main shaft to the atomizing high temperature nozzles of the rotating nozzle and the ventilation rod. S3: Segmented reaction and waste heat recovery. The temperature of the reaction section is controlled at 170-190℃ and the reaction pressure is 0.8-1.2MPa. The material stays in the horizontal reactor for 3-5 hours. The feeding rod carries the material through the preheating section, reaction section and heat preservation section in sequence. When the material enters the reaction section, the electromagnetic conveying pump on the second external guide pipe is started to recover the high-temperature steam in the heat preservation section and preheat the reaction section. When the material enters the heat preservation section, the electromagnetic conveying pump on the first external guide pipe is started to transfer the waste heat in the heat preservation section to the preheating section. S4: Furfural collection and purification. The furfural gas phase generated by hydrolysis is discharged through the gas phase outlet at the top of the horizontal reactor. After removing coke powder and tar impurities, it is sent to the distillation column for atmospheric distillation, condensation and separation, vacuum distillation and dehydration purification in sequence to obtain furfural product with a purity ≥99.5%. S5: Residue treatment and recycling. The solid residue after hydrolysis enters the discharge mechanism through the solid discharge port at the other end of the horizontal kettle. The neutralization spray component sprays lime slurry to neutralize the residual acid in the residue. The waste heat of the residue is recovered during the twin-screw conveying process. The neutralized residue is dried and used to prepare biomass organic fertilizer or biomass fuel.

[0014] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. This invention uses the spiral scraper, wear-resistant scraper and rotating nozzle of the coke breaking mechanism to break up and stir the material, ensure uniform contact between the catalyst and the material, reduce coking in the side reaction, and scrape off the coke on the inner wall of the horizontal reactor, the steam channel and the heat exchange surface in real time. This inhibits coking and blockage from the source, eliminates the need for frequent shutdowns to clean the reactor, reduces the maintenance cost of the equipment, ensures the continuity of production and improves the stability of production capacity. 2. The steam distribution mechanism of this invention adopts a combination of steam delivery through the steam flow channel in the main shaft cavity and spraying through the rotating nozzle, along with the atomizing high-temperature nozzle of the ventilation rod, to achieve uniform coverage and heating of the material in the horizontal reactor, avoiding the problems of local overheating exacerbating coking and local underheating reducing efficiency, improving the utilization rate of steam, solving the defects of low steam utilization rate in the prior art, reducing energy and water consumption, and meeting the requirements of energy-saving production. 3. The waste heat recovery mechanism of this invention consists of three independent heat exchange chambers: a preheating section, a reaction section, and a heat preservation section. Combined with an external guide pipe and an electromagnetic transfer pump, it realizes the cascade recovery and recycling of heat dissipation from the wall of the horizontal vessel, as well as the waste heat from residue and gas phase. This reduces energy waste, lowers the cooling cost of the workshop, and further reduces the overall production energy consumption. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention; Figure 2 This is a schematic diagram of the structure of the coke breaking mechanism of the present invention; Figure 3 This is a schematic diagram of the structure of the coke breaking knife assembly of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram at point A; Figure 5 This is a schematic diagram of the main steam pipe of the present invention; Figure 6 For the present invention Figure 5 Enlarged structural diagram at point B; Figure 7 This is a schematic diagram of the jacket structure of the present invention; Figure 8 This is a schematic diagram of the waste heat recovery mechanism of the present invention; Figure 9 This is a schematic diagram of the solid phase discharge port structure of the present invention; Figure 10 This is a schematic diagram of the material discharge mechanism of the present invention; Figure 11 This is a flowchart of the preparation method of furfural according to the present invention.

[0016] In the diagram: 1. Horizontal vessel body; 2. Drive mechanism; 3. Coke breaking mechanism; 31. Main shaft; 32. Coke breaking knife assembly; 321. Ventilation rod; 322. Spiral scraper rod; 323. Feeding rod; 324. Atomizing high-temperature nozzle; 325. Wear-resistant scraper; 4. Steam distribution mechanism; 41. Main steam pipe; 42. Rotary nozzle; 43. High-temperature steam conveying pipeline; 5. Waste heat recovery mechanism; 51. Jacket; 511. Preheating section 512. Reaction section; 513. Insulation section; 52. Heating pipe; 53. Preheating ring pipe; 54. Reaction pipe; 55. First external guide pipe; 56. Insulation pipe; 57. Second external guide pipe; 58. Electromagnetic conveying pump; 6. Discharge mechanism; 61. Conveying chamber; 62. Twin screw; 63. Neutralization spray assembly; 7. Biomass inlet; 8. Catalyst inlet; 9. Solid phase outlet; 10. Gas phase outlet. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "comprising" or "including," and similar terms used in this invention, mean that the element or object preceding the term encompasses the element or object listed following the term and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but may also include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0019] like Figures 1 to 11As shown, a high-purity furfural preparation device includes a horizontal vessel 1, a drive mechanism 2, a coke breaking mechanism 3, a steam distribution mechanism 4, a waste heat recovery mechanism 5, and a discharge mechanism 6. The coke breaking mechanism 3 includes a main shaft 31 and a coke breaking knife assembly 32. The inner cavity of the main shaft 31 is provided with a channel for steam circulation and is arranged along the axial direction of the horizontal vessel 1. The coke breaking knife assembly 32 is provided with a wear-resistant scraper 325 that fits against the inner wall of the horizontal vessel 1. The steam distribution mechanism 4 includes a main steam pipe 41 connected to the inner cavity of the main shaft 31 and multiple rotating nozzles 42. The rotating nozzles 42 are connected to the main shaft 31 to ensure steam distribution. The waste heat recovery mechanism 5 includes a jacket 51 wrapped around the outside of the horizontal vessel 1. The jacket 51 is divided into three independent heat exchange chambers along the axial direction: a preheating section 511, a reaction section 512, and a heat preservation section 513, and is connected in series with a boiler feedwater preheating pipeline. The jacket 51 is segmented to realize the cascade utilization of waste heat, with a reasonable layout to meet the heating needs of different zones at different temperatures.

[0020] The horizontal reactor body 1 has a biomass inlet 7 and a catalyst inlet 8 at the top, a solid phase outlet 9 at the bottom, and a gas phase outlet 10 at the top. The separate biomass inlet 7 and catalyst inlet 8 allow for precise and separate feeding of raw materials and catalysts, avoiding uneven catalyst distribution caused by mixed feeding and improving the efficiency of the hydrolysis reaction. The separate solid phase outlet 9 and gas phase outlet 10 allow for the separate discharge of residue and furfural gas phase, avoiding cross-contamination. At the same time, the gas phase outlet 10 is located at the top to facilitate the rapid discharge of furfural gas phase, while the solid phase outlet 9 is located at the bottom to facilitate the smooth discharge of residue, ensuring the continuity of production.

[0021] The drive mechanism 2 includes two drive motors, both of which are fixed to the side wall of the horizontal reactor body 1. The output ends of the two drive motors are respectively connected to the main shaft 31 and the discharge mechanism 6. The drive mechanism 2 is fixed to the side wall of the horizontal reactor body 1, which ensures the stability of the installation and avoids shaking during operation. The output ends of the two drive motors are connected to the main shaft 31 and the discharge mechanism 6, providing stable power support for the coke scraping and feeding of the coke crushing knife group 32 and the conveying of the solid residue after reaction by the twin screw 62.

[0022] The coke breaking knife assembly 32 also includes a ventilation rod 321, multiple spirally arranged spiral scraper rods 322, and multiple feeding rods 323 located inside the spirally arranged spiral scraper rods 322. The feeding rods 323 and the spiral scraper rods 322 are all connected to the outer wall of the main shaft 31 through the ventilation rod 321. There are multiple ventilation rods 321 and the ventilation rods 321 are connected to the inner cavity of the main shaft 31. The other end of the ventilation rod 321 is provided with multiple fan-shaped atomizing high-temperature nozzles 324. Multiple wear-resistant scrapers 325 are provided on the outer wall of the spiral scraper rods 322 and are arranged sequentially along the spiral path of the spiral scraper rods 322. The front end of the wear-resistant scraper 325 is stepped. The ventilation rod 321 is connected to the inner cavity of the main shaft 31, which can accurately deliver steam to the atomizing high-temperature nozzle 324. The fan-shaped atomization can achieve uniform spraying of high-temperature steam on the surface of the material for heating, thereby improving the hydrolysis efficiency. The spiral scraper rod 322 works in conjunction with the feeding rod 323 to disperse the material to ensure uniform contact of the catalyst and to stably transport the material, avoiding material accumulation. The wear-resistant scraper 325 is arranged along the spiral route. The stepped front end of the wear-resistant scraper 325 can completely scrape off the coke on the inner wall of the horizontal reactor body 1, extending the service life of the wear-resistant scraper 325 and preventing coking and blockage from the source.

[0023] One end of the main steam pipe 41 is connected to a high-temperature steam conveying pipe 43, which is located at one end of the horizontal vessel body 1. Multiple air holes communicating with rotating nozzles 42 are opened on the outer wall of the main steam pipe 41. These rotating nozzles 42 are rotatably connected to the outer wall of the main shaft 31. The high-temperature steam conveying pipe 43, located at one end of the horizontal vessel body 1, facilitates rapid steam delivery to the main steam pipe 41. The air hole design of the main steam pipe 41 ensures uniform steam distribution to each rotating nozzle 42. The rotating nozzles 42, rotatably connected to the main shaft 31, can rotate autonomously using the propulsive force of the steam ejection. Combined with the rotation of the main shaft 31, this achieves uniform spray heating of the material throughout the horizontal vessel body 1, preventing localized overheating and coking, and improving steam utilization.

[0024] The discharge mechanism 6 includes a conveying chamber 61, a twin screw 62, and a neutralization spray assembly 63. The feed end of the conveying chamber 61 is sealed and connected to the solid discharge port 9 of the horizontal reactor body 1. The twin screw 62 is horizontally arranged inside the conveying chamber 61. The surface of the twin screw 62 is coated with a tungsten carbide wear-resistant and corrosion-resistant coating. The twin screw 62 is connected to the output end of the drive motor adjacent to the drive mechanism 2. The neutralization spray assembly 63 is arranged at the top of the conveying chamber 61, and the spraying direction is towards the conveying working surface of the twin screw 62. The conveying chamber 61 is sealed and connected to the solid discharge port 9 to prevent residue leakage and environmental pollution. The horizontally positioned twin screws 62 enable stable conveying of the residue. The tungsten carbide wear-resistant and corrosion-resistant coating enhances the wear resistance and corrosion resistance of the twin screws 62, extending the service life of the device. The neutralization spray assembly 63 sprays water towards the conveying working surface of the twin screws 62, which can neutralize the acid in the residue in real time, preventing acid from corroding the conveying chamber 61 and the twin screws 62, while also providing conditions for the subsequent resource recycling of the residue.

[0025] A heating pipe 52 is connected to the top of the preheating section 511. The other end of the heating pipe 52 is connected to two preheating ring pipes 53 located in the jacket 51. The other ends of the two preheating ring pipes 53 are connected to a reaction pipe 54 and a first external guide pipe 55. The reaction pipe 54 is located in the reaction section 512. The other end of the reaction pipe 54 is connected to a heat preservation pipe 56 and two second external guide pipes 57. The other end of the second external guide pipes 57 is connected to the other end of the horizontal vessel body 1 and communicates with the inner cavity of the horizontal vessel body 1. The heat preservation pipe 56 is located in the heat preservation section 513. Electromagnetic transfer pumps 58 are provided on both the first external guide pipe 55 and the second external guide pipes 57. Gas filters are provided in the air inlet and outlet of both ends of the electromagnetic transfer pumps 58 to filter impurities contained in the gas. The heating pipe 52, connected to the top of the preheating section 511, serves as an input channel for external high-temperature steam or waste heat steam, used to supply heat to the jacket 51. Two sets of preheating ring pipes 53, connected to the other end of the pipe, are located within the preheating section 511, ensuring that the steam input from the heating pipe 52 is evenly distributed throughout the preheating section 511, achieving uniform and stable preheating of the materials within the preheating section 511 and preventing localized coking. The reaction pipe 54, located within the reaction section 512, receives the steam supplied by the preheating ring pipes 53. Simultaneously, high-temperature steam from the other end of the horizontal reactor 1 can be introduced through the second external guide pipe 57, providing a stable and controllable reaction temperature of 170-190℃ for the reaction section 512 to ensure efficient hydrolysis of the material to produce furfural. The insulation pipe 56, located within the insulation section 513, receives the steam supplied by the reaction pipe 54, providing a suitable insulation temperature for the insulation section 513 and cooperating with steam extraction to achieve precise temperature control. One end of an external guide pipe 55 is connected to the preheating ring pipe 53, and the other end is connected to the interior of the horizontal vessel 1. One end of a second external guide pipe 57 is connected to the reaction pipe 54, and the other end is connected to the other end of the horizontal vessel 1 and communicates with the inner cavity of the horizontal vessel 1. Both the first external guide pipe 55 and the second external guide pipe 57 are equipped with electromagnetic transfer pumps 58, which serve as power components for directional steam transfer. They can respectively pump excess high-temperature water vapor in the insulation section 513 to the preheating section 511 to achieve waste heat recovery, and pump high-temperature steam near the insulation section 513 of the horizontal vessel 1 to the reaction section 512 to achieve steam reuse, thereby realizing controllable circulation of temperature and waste heat distribution in each section. The gas filters set at both ends of the electromagnetic transfer pump 58 can filter impurities such as coke powder and residue in the steam to prevent pipeline blockage, ensure stable operation of the device, and ensure smooth steam flow and heat exchange efficiency.

[0026] A method for preparing high-purity furfural includes the following steps: S1: Raw material pretreatment: Crush corn cobs, sugarcane bagasse or straw biomass raw materials to 20-40 mesh, and mix them evenly with 1.5%-3% by mass of dilute sulfuric acid catalyst at a solid-liquid ratio of 1:3-1:5 to obtain a mixture. S2: After feeding, start the device to continuously feed the mixed material into the inner cavity of the horizontal reactor 1 through the biomass feed port 7 at one end of the horizontal reactor 1. Start the drive mechanism 2 to drive the main shaft 31, the coke breaking knife group 32, the spiral scraper 322 and the wear-resistant scraper 325 to rotate at a speed of 5-15r / min. At the same time, open the high-temperature steam conveying pipeline 43 to send high-temperature steam into the main steam pipe 41, and distribute it through the inner cavity of the main shaft 31 to the atomizing high-temperature nozzles 324 of the rotating nozzle 42 and the ventilation rod 321 for spraying. S3: Segmented reaction and waste heat recovery. The temperature of the reaction section 512 is controlled at 170-190℃ and the reaction pressure is 0.8-1.2MPa. The material stays in the horizontal reactor 1 for 3-5 hours. The feeding rod 323 drives the material through the preheating section 511, the reaction section 512 and the heat preservation section 513 in sequence. When the material enters the reaction section 512, the electromagnetic transfer pump 58 on the second external guide pipe 57 is started to recover the high-temperature steam in the heat preservation section 513 and preheat the reaction section 512. When the material enters the heat preservation section 513, the electromagnetic transfer pump 58 on the first external guide pipe 55 is started to transfer the waste heat of the heat preservation section 513 to the preheating section 511. S4: Furfural collection and purification. The furfural gas phase generated by hydrolysis is discharged through the gas phase outlet 10 at the top of the horizontal reactor body 1. After removing coke powder and tar impurities, it is sent to the distillation column for atmospheric distillation, condensation and separation, vacuum distillation and dehydration purification in sequence to obtain furfural product with a purity ≥99.5%. S5: Residue treatment and recycling. The solid residue after hydrolysis enters the discharge mechanism 6 through the solid discharge port 9 at the other end of the horizontal kettle body 1. The neutralization spray component 63 sprays lime milk to neutralize the residual acid in the residue. The twin screw 62 recovers the waste heat of the residue during the conveying process. The neutralized residue is dried and used to prepare biomass organic fertilizer or biomass fuel.

[0027] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. An apparatus for preparing high-purity furfural, characterized in that, It includes a horizontal vessel body (1), a drive mechanism (2), a coke breaking mechanism (3), a steam distribution mechanism (4), a waste heat recovery mechanism (5), and a discharge mechanism (6); The coke breaking mechanism (3) includes a main shaft (31) and a coke breaking knife assembly (32). The inner cavity of the main shaft (31) is provided with a channel for steam circulation and is arranged along the axial direction of the horizontal vessel body (1). The coke breaking knife assembly (32) is provided with a wear-resistant scraper (325) that fits against the inner wall of the horizontal vessel body (1). The steam distribution mechanism (4) includes a main steam pipe (41) connected to the inner cavity of the main shaft (31) and multiple rotating nozzles (42). The waste heat recovery mechanism (5) includes a jacket (51) wrapped around the outside of the horizontal vessel body (1). The jacket (51) is divided into three independent heat exchange chambers along the axial direction: a preheating section (511), a reaction section (512), and a heat preservation section (513), and is connected in series with the boiler feedwater preheating pipeline.

2. The apparatus for preparing high-purity furfural according to claim 1, characterized in that, The horizontal reactor body (1) is provided with a biomass inlet (7) and a catalyst inlet (8) at the top, a solid phase outlet (9) at the bottom of the other end, and a gas phase outlet (10) at the top.

3. The apparatus for preparing high-purity furfural according to claim 1, characterized in that, The driving mechanism (2) includes two driving motors, both of which are fixed on the side wall of the horizontal vessel body (1). The output ends of the two driving motors are respectively connected to the main shaft (31) and the discharge mechanism (6).

4. The apparatus for preparing high-purity furfural according to claim 1, characterized in that, The coke breaking knife assembly (32) also includes a ventilation rod (321), a plurality of spiral scraper rods (322) arranged in a spiral shape, and a plurality of feeding rods (323) located inside the spiral scraper rods (322) arranged in a spiral shape. The feeding rods (323) and the spiral scraper rods (322) are all connected to the outer wall of the main shaft (31) through the ventilation rod (321). There are a plurality of ventilation rods (321) and the ventilation rods (321) are connected to the inner cavity of the main shaft (31). The other end of the ventilation rod (321) is provided with a plurality of atomizing high temperature nozzles (324) arranged in a fan shape. Multiple wear-resistant scrapers (325) are disposed on the outer wall of the spiral scraper (322) and arranged sequentially along the spiral path of the spiral scraper (322). The front end of the wear-resistant scraper (325) is stepped.

5. The apparatus for preparing high-purity furfural according to claim 1, characterized in that, One end of the main steam pipe (41) is connected to a high-temperature steam conveying pipe (43), which is located at one end of the horizontal vessel body (1). Multiple air holes communicating with rotating nozzles (42) are opened on the outer wall of the main steam pipe (41), and the multiple rotating nozzles (42) are rotatably connected to the outer wall of the main shaft (31).

6. The apparatus for preparing high-purity furfural according to claim 1, characterized in that, The discharge mechanism (6) includes a conveying chamber (61), a twin screw (62), and a neutralization spray assembly (63). The feed end of the conveying chamber (61) is sealed and connected to the solid discharge port (9) of the horizontal reactor body (1). The twin screw (62) is horizontally arranged in the conveying chamber (61). The surface of the twin screw (62) is coated with a tungsten carbide wear-resistant and corrosion-resistant coating. The twin screw (62) is connected to the output end of the drive motor adjacent to the drive mechanism (2). The neutralizing spray assembly (63) is located on the top of the conveying cavity (61), with the spraying direction facing the conveying working surface of the twin screw (62).

7. The apparatus for preparing high-purity furfural according to claim 1, characterized in that, The top end of the preheating section (511) is connected to a heating pipe (52), and the other end of the heating pipe (52) is connected to two preheating ring pipes (53) located in the jacket (51). The other ends of the two preheating ring pipes (53) are connected to a reaction pipe (54) and a first external guide pipe (55). The reaction tube (54) is located inside the reaction section (512). The other end of the reaction tube (54) is connected to a heat preservation tube (56) and two second external guide tubes (57). The other end of the second external guide tube (57) is connected to the other end of the horizontal vessel body (1) and communicates with the inner cavity of the horizontal vessel body (1). The insulation pipe (56) is located within the insulation section (513); Both the first external guide tube (55) and the second external guide tube (57) are equipped with electromagnetic delivery pumps (58), and both ends of the electromagnetic delivery pumps (58) are equipped with gas filters.

8. A method for preparing high-purity furfural, using the apparatus for preparing high-purity furfural according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Raw material pretreatment: Crush corn cobs, sugarcane bagasse or straw biomass raw materials to 20-40 mesh, and mix them evenly with dilute sulfuric acid catalyst with a mass fraction of 1.5%-3% at a solid-liquid ratio of 1:(3-5) to obtain a mixture. S2: After feeding, start the device to continuously feed the mixed material into the inner cavity of the horizontal reactor (1) through the biomass feed port (7) at one end of the horizontal reactor (1), start the drive mechanism (2) to drive the main shaft (31), the coke breaking knife group (32), the spiral scraper (322) and the wear-resistant scraper (325) to rotate at a speed of 5-15r / min, and at the same time open the high temperature steam conveying pipeline (43) to send the high temperature steam into the main steam pipe (41), and distribute it through the inner cavity of the main shaft (31) to the atomizing high temperature nozzle (324) of the rotating nozzle (42) and the ventilation rod (321) for spraying out; S3: Segmented reaction and waste heat recovery. The temperature of the reaction section (512) is controlled at 170-190℃ and the reaction pressure is 0.8-1.2MPa. The material stays in the horizontal kettle (1) for 3-5 hours. The feeding rod (323) drives the material through the preheating section (511), the reaction section (512) and the heat preservation section (513) in sequence. When the material enters the reaction section (512), the electromagnetic transfer pump (58) on the second external guide pipe (57) is started to recover the high temperature steam in the heat preservation section (513) and preheat the reaction section (512). When the material enters the heat preservation section (513), the electromagnetic transfer pump (58) on the first external guide pipe (55) is started to transfer the waste heat of the heat preservation section (513) to the preheating section (511). S4: Furfural collection and refining: The furfural gas phase generated by hydrolysis is discharged through the gas phase outlet (10) at the top of the horizontal kettle body (1). After removing coke powder and tar impurities, it is sent to the distillation column for atmospheric distillation, condensation and stratification, vacuum distillation and dehydration refining in sequence to obtain furfural product with a purity ≥99.5%. S5: Residue treatment and recycling. The solid residue after hydrolysis enters the discharge mechanism (6) through the solid discharge port (9) at the other end of the horizontal kettle body (1). The neutralization spray component (63) sprays lime milk to neutralize the residual acid in the residue. The residual heat is recovered during the twin screw (62) conveying process. The neutralized residue is dried and used to prepare biomass organic fertilizer or biomass fuel.

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