A continuous pyrolysis device and method

Abstract

The embodiment of the present invention provides a continuous pyrolysis device and method. The device includes a spiral tube, a rotating shaft, spiral blades, a driver, a microwave generator, etc. The spiral tube is divided into a feeding section, a discharging section and a multi-stage reaction section, and a sealing section is arranged between each adjacent area. After the raw material enters, it is stirred and pushed by the spiral blades, and passes through each stage of the reaction section in turn. The raw material is efficiently pyrolyzed in different reaction sections by microwave heating; a continuous expansion section and a compression section are arranged in the reaction section, and the expansion section provides expansion space for a large amount of gas rapidly generated by the pyrolysis of the raw material. Under the expansion pressure and the compression of the compression section, the gas automatically passes through the breathable baffle and is mixed in the mixing and exhaust unit and discharged for subsequent processing and utilization. The device and method have centralized heating, fast control response, good selectivity, automatic exhaust, clean discharge, and reasonable structural changes, and can realize efficient and continuous pyrolysis processes of different raw material components or different reaction stages.

Description

Technical Field

[0001] The present invention belongs to the technical field of harmless treatment of organic solid waste, and in particular relates to a continuous pyrolysis device. The present invention also provides an organic solid waste pyrolysis method, which realizes pyrolysis of organic solid waste based on the continuous pyrolysis device. Background Art

[0002] Pyrolysis is an efficient method for treating organic solid waste (organic solid waste) such as biomass, domestic garbage, waste plastics, and waste rubber. Compared with traditional treatment methods, it has the advantages of short treatment cycle, high conversion efficiency, obvious volume reduction effect, efficient solidification of heavy metals, and avoidance of the generation of harmful substances such as dioxins. At the same time, it can also obtain three products of solid, liquid, and gas, and further prepare high-value chemicals or fuels. Therefore, pyrolysis has great application and promotion prospects in the current field of harmless disposal and high-value utilization of organic solid waste.

[0003] The spiral reactor is a commonly used pyrolysis device, which usually uses wall heating or solid heat carrier for heat exchange. It relies on the shaft with spiral blades to rotate in the closed tube wall to push the raw materials forward gradually to achieve continuous pyrolysis reaction. Compared with other pyrolysis devices such as fixed beds and fluidized beds, it has the advantages of stage controllable, continuous operation, and low heat loss. However, simply transferring heat from the wall from the outside to the inside can easily lead to uneven temperature distribution. Even if solid heat carriers are used for auxiliary heat exchange, the temperature will gradually decrease along the axial direction of the spiral tube due to the gradual decrease in the heat storage capacity of the heat carrier itself, and it is difficult to stably maintain an efficient reaction. At the same time, for these traditional heat transfer methods, not only do they occupy a large space, but also due to the large thermal inertia of the device, the regulation response is very slow, and it is difficult to flexibly control the temperature according to the changes in raw material components and reaction stages, and an efficient pyrolysis process cannot be achieved.

[0004] Microwaves are an efficient heating method. Microwaves form a high-frequency electromagnetic field, which causes specific molecules inside the raw materials to vibrate violently, resulting in strong collisions and friction, generating heat, and eventually the temperature rises sharply, and the raw material components are directly precipitated or decomposed. Unlike external heating methods such as hot air, flames, and electric heating, microwaves can directly heat the molecules inside the raw materials without any heat conduction process, and the heating rate is fast and uniform. Microwaves can achieve precise heating of special components and timely regulation of working conditions by pyrolysis devices, but there are still many problems with microwave pyrolysis technology. For conventional microwave pyrolysis devices, such as international patent WOCN14076479 and Chinese patent document CN103923673A, propeller blades or conveyor belts are set in the microwave reaction chamber to transport raw materials. The reaction space is large, which is conducive to the rapid expansion of pyrolysis gas, but it will cause the dissipation of microwaves, making it difficult to concentrate heat and reduce heating efficiency. The organic combination of microwave technology and spiral reactor, such as Chinese patent documents CN104560074A and CN106738435A, etc., the outer edge of the spiral blade is close to the wall of the drying chamber pipe, and the gas is released only through a small exhaust pipe, which can reduce heat loss. However, this exhaust process is only suitable for raw materials with low volatility and low moisture or slow pyrolysis. Otherwise, the rapid heating of microwaves will cause a large amount of gas to be released sharply, the volume will increase suddenly, and it cannot be removed in time, and eventually the pressure will be too high to damage the equipment.

[0005] Therefore, in order to give full play to the advantages of microwave technology and spiral reactors, achieve accurate and efficient pyrolysis of organic solid waste raw materials, and improve the safety of the device and space utilization, it is necessary to develop a new type of pyrolysis device. Summary of the invention

[0006] The present invention aims to solve the technical problem that the existing pyrolysis devices have shortcomings such as uneven heat transfer, long pyrolysis cycle, slow regulation response, low space utilization, difficulty in timely exhaust, and inability to adapt to pressure changes, making it difficult to achieve efficient and continuous pyrolysis processes with different raw material components or different reaction stages.

[0007] In order to solve the above technical problems, an embodiment of the present invention provides a continuous pyrolysis device, including a spiral feeding system and a microwave generating system;

[0008] The spiral feeding system comprises a spiral tube, a rotating shaft, spiral blades and a driver. The spiral tube is a hollow circular tube arranged transversely, a feeding section is arranged at one end, a feeding port for feeding raw materials is arranged at the top of the feeding section, and a discharging section is arranged at the other end, a discharging port for discharging materials is arranged at the bottom of the discharging section; the rotating shaft is coaxially arranged in the spiral tube and passes through from the feeding section to the discharging section, the spiral blades are continuously fixedly arranged around the rotating shaft, and the driver is connected to and drives the rotating shaft to rotate; the microwave generating system comprises a plurality of microwave generators;

[0009] Between the feed section and the discharge section, there are one or more reaction sections for raw material pyrolysis reaction; between two adjacent reaction sections, and between the feed section, the discharge section and the reaction section, there are sealing sections respectively; wherein:

[0010] The reaction section of each stage is divided into a continuous expansion section and a compression section along the raw material conveying direction, and the shaft diameter of the rotating shaft gradually decreases in the expansion section and gradually increases in the compression section along the raw material conveying direction;

[0011] A plurality of microwave generators are arranged axially on the side of each reaction section, and are used to emit microwaves into the reaction section to heat the raw materials;

[0012] A sealing sheet is installed on the edge of the spiral blade in the sealing section, and the sealing sheet is attached to the inner wall of the spiral tube to form a seal;

[0013] A mixing exhaust unit for mixing and exhausting the water vapor in the reaction section is connected to the top of each reaction section.

[0014] Preferably, each of the mixed exhaust units comprises a hollow box whose cross-sectional area gradually increases from top to bottom, the top of the box is connected to a mixing air duct, a spiral channel for gas mixing is arranged in the mixing air duct; the bottom of the box is open, a breathable baffle with holes is arranged at the opening, and the box is connected to the top of the reaction section through the bottom opening; the water vapor in the reaction section passes through the breathable baffle into the box under the action of its own expansion pressure and the extrusion of the compression section, mixes in the mixing air duct, and is discharged through the mixing air duct for subsequent processing and utilization.

[0015] Further preferably, an opening is provided at the top of the reaction section of each stage in the entire area of ​​the compression section and a partial area of ​​the expansion section to communicate with the bottom of the box of the mixing and exhaust unit.

[0016] Preferably, the length of the sealing section of the spiral tube is not less than the pitch of the spiral blade in the sealing section.

[0017] Preferably, the reaction section inside the spiral tube is filled with a heating ball, the heating ball is made of a microwave absorbing material, and the heating ball absorbs microwaves to increase the temperature, thereby indirectly heating the raw material to cause a pyrolysis reaction.

[0018] As a preferred embodiment of the aforementioned continuous pyrolysis device, a stirring rod may be fixedly connected to the spiral blade and / or friction patterns may be provided on the inner wall of the spiral tube to enhance the stirring effect on the raw material.

[0019] The embodiment of the present invention further provides a method for pyrolyzing organic solid waste, which uses the above-mentioned continuous pyrolysis device to pyrolyze organic solid waste, comprising the following steps:

[0020] Step 1. Turn on the rotating shaft to drive the spiral blade to rotate, and start the microwave generator to emit microwaves into the reaction section of the spiral tube;

[0021] Step 2. The raw material is fed into the spiral tube from the feed port, and is stirred and pushed by the spiral blades to pass through each level of reaction section in sequence. The raw material is heated by microwaves in each level of reaction section, and its components are separated or decomposed;

[0022] Step 3. The gas generated by each stage of the reaction passes through the air-permeable baffle and enters the corresponding mixed exhaust unit, and then is discharged through the mixed air duct for subsequent treatment and utilization;

[0023] Step 4. The residual carbon and waste residue remaining after the pyrolysis of the raw materials are discharged from the spiral tube through the discharge port for subsequent treatment.

[0024] Preferably, in step 2, the raw materials are directly heated by absorbing microwaves in each reaction section, and / or are indirectly heated by absorbing microwaves through heating balls filled in each reaction section.

[0025] The core of the continuous pyrolysis device and method provided by the technical solution of the present invention is a multi-stage reaction section connected in sequence in a spiral tube, a continuous expansion section and compression section in the reaction section, a sealing sheet for sealing the reaction section, a microwave generator for effective temperature control, and a mixed exhaust unit for automatic exhaust by gas expansion. The raw material enters the continuous pyrolysis device, is stirred and pushed by the spiral blades, passes through the reaction sections of each level in sequence, and is rapidly volatilized or decomposed by microwave heating to achieve efficient pyrolysis of different raw material components or different reaction stages; the expansion section in different reaction sections provides expansion space for a large amount of rapidly generated gas, and these gases automatically pass through the air-permeable partition under their own expansion pressure and the extrusion of the compression section to enter their respective mixed exhaust units for mixing, and are discharged through the mixed air duct for subsequent treatment and utilization; and the residual carbon and waste residue left by pyrolysis are discharged through the discharging unit for subsequent treatment.

[0026] The beneficial effects of the above technical solution of the embodiment of the present invention are as follows:

[0027] 1. The pyrolysis reaction uses microwave heating and has the following excellent characteristics:

[0028] Fast heating rate, energy saving and high efficiency: Microwaves directly act on raw materials or heat without heat conduction, with a fast heating rate and small thermal gradient, which can shorten the reaction cycle; other structures of the device cannot absorb microwaves, so heat loss is small and energy consumption is saved.

[0029] 2. Good selectivity and concentrated heat: Microwaves of a specific frequency can only be absorbed by special raw material components or absorbing materials, and the heating range is concentrated. It is easy to control the temperature of different reaction sections and the objects that absorb microwave energy, achieve the best working conditions for different reaction processes, and ensure efficient directional reactions.

[0030] 3. Small thermal inertia and fast response: Microwaves of a specific frequency can only heat the heating ball composed of raw material components or absorbing materials, while other structures of the device have little waste heat, small thermal inertia, and no thermal hysteresis effect. The temperature can be adjusted in time and started and stopped quickly, the state of the reaction process in different areas can be flexibly changed, and a stable reaction temperature can be maintained.

[0031] 4. Make the raw materials puffed and loose: Microwaves can directly heat the raw material components, quickly heat up to produce a large amount of gas, and form many tiny channels, so that the raw materials expand and become loose, and are not prone to sticking or accumulation, thus ensuring the stable operation of the equipment.

[0032] 5. Reasonable reaction space structure: The reaction section is a continuous expansion section and compression section, and the shaft diameter first decreases and then increases, providing a reasonable reaction space to adapt to pressure changes; the raw material components absorb heat and rapidly produce a large amount of gas, and the expansion section can provide expansion space for the raw material and gas to effectively release the pressure; in the later stage of the reaction, the gas precipitated from the raw material decreases, and the volume of the raw material becomes smaller, the compression section can reduce the invalid space, assist in exhaust, compress the residual raw material, and provide a space basis for the next reaction section expansion section.

[0033] 6. Convenient reaction control and wide adaptability of raw materials: By controlling the feed speed of the device, the microwave emission power and frequency of different reaction sections, the rotation speed of the rotating shaft, etc., the reaction temperature, reaction time, reaction mode and other conditions of different processes can be adjusted in time. At the same time, the spiral equipment with different reaction section combinations can be flexibly replaced, so as to accurately control the pyrolysis process based on different raw materials and the required target products and achieve efficient conversion; in addition, microwaves can penetrate into the raw materials for uniform heating, and have lower requirements on the size and shape of the raw materials, which can reduce the power consumption of crushing pretreatment.

[0034] 7. Effective dechlorination and clean emission: Pyrolysis is an anaerobic process that can produce reducing components such as H2 and CO, and the temperature is relatively low. It can effectively inhibit the generation of harmful substances such as dioxins from the source and achieve efficient dechlorination.

[0035] 8. Automatic exhaust and safe operation: The spiral device has a compact space and strong pressure resistance. The spiral blades with sealing sheets in the sealing section can effectively seal the spiral tube to prevent gas from escaping and avoid mutual interference between gases in different reaction sections. At the same time, when the gas in each reaction section expands rapidly, it can directly enter the corresponding mixed exhaust unit through the breathable baffle to achieve automatic exhaust, instead of staying in the spiral tube, causing pipeline blockage and equipment damage.

[0036] 9. Compact structure and easy to seal: No additional auxiliary equipment such as heat exchange is required. At the same time, different reaction sections are arranged in the same spiral tube. The device corresponding to the unit raw material processing is small in size, compact in structure, and has high space utilization. In addition, the device has few rotating parts and is not directly heated, so the temperature is low, which helps to improve the overall sealing of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A structural front view of a continuous pyrolysis device provided by an embodiment of the present invention;

[0038] Figure 2 for Figure 1 A cross-sectional view of the continuous pyrolysis device shown;

[0039] Figure 3 A flow chart of the steps of a method for pyrolysis of organic solid waste provided in an embodiment of the present invention.

[0040] [Description of main component symbols]

[0041] 1- spiral tube; R1-feeding section; R2-discharging section; R3-reaction section; R31-compression section; R32-expansion section; R4-sealing section; 11-feeding port; 12-discharging port; 2-rotating shaft; 3-spiral blade; 31-sealing sheet; 4-driver; 5-mixing exhaust unit; 51-box; 52-breathable partition; 53-mixing air guide pipe; 531-spiral channel; 6-microwave generator. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0044] In view of the existing technical problems, the present invention provides a continuous pyrolysis device and a solid waste pyrolysis method using the continuous pyrolysis device, which has the characteristics of fast heating rate, concentrated heat, good selectivity, fast regulation response, expanded raw materials, automatic exhaust, good sealing, high space utilization, wide raw material adaptability, clean discharge, and effective adaptation to pressure and raw material volume changes, and can realize efficient and continuous pyrolysis process of different raw material components or different reaction stages.

[0045] In order to realize the above technical solution, Figure 1 and Figure 2As shown, an embodiment of the present invention provides a continuous pyrolysis device, including a spiral feeding system and a microwave generating system, wherein the spiral feeding system includes a spiral tube 1, a rotating shaft 2, a spiral blade 3, a driver 4 and a mixed exhaust unit, wherein:

[0046] The spiral tube 1 is a hollow circular tube arranged horizontally, with a feed section R1 at one end, a feed port 11 at the top of the feed section R1, and a discharge section R2 at the other end, and a discharge port 12 at the bottom of the discharge section R2; the rotating shaft 2 is coaxially arranged in the spiral tube 1 and passes through the feed section R1 to the discharge section R2, the spiral blades 3 are continuously and fixedly arranged around the rotating shaft 2, and the driver 4 is connected to and drives the rotating shaft 2 to rotate; as a better embodiment, the driver 4 can be placed outside the spiral tube 1, and the rotating shaft 2 extends from the feed section to the spiral tube 1 and is connected to the driver 4; as another better embodiment, the inner wall of the spiral tube 1 can be provided with friction lines, and the spiral blades 3 can be fixedly connected to a stirring rod to enhance the stirring effect on the raw materials.

[0047] Between the feeding section R1 and the discharging section R2 of the spiral tube 1, there are more than one reaction section R3 for raw material pyrolysis reaction, which can be named as the first reaction section, the second reaction section, ... the Nth reaction section in the direction of raw material transportation. For the convenience of display, Figure 1 and Figure 2 Only one reaction section is shown in the simplified diagram, and the other reaction sections are omitted. Each stage reaction section R3 is divided into a continuous expansion section R32 and a compression section R31 along the raw material conveying direction. The shaft diameter of the rotating shaft 2 gradually decreases in the expansion section R32 and gradually increases in the compression section R31 along the raw material conveying direction.

[0048] A mixed exhaust unit 5 for mixing and exhausting the water vapor in the reaction section R3 is connected to the top of each stage of reaction section R3. The main body of each mixed exhaust unit 5 is a hollow box 51 with a cross-sectional area gradually increasing from top to bottom. The top of the box 51 is connected to a mixed air pipe 53, and a spiral channel 531 for gas mixing is arranged in the mixed air pipe 53; the bottom of the box 51 is open, and a perforated air baffle 52 is arranged at the opening. The box 51 is connected to the top of the reaction section R3 through the bottom opening; the water vapor in the reaction section R3 enters the box 51 through the permeable baffle 52, and is mixed and discharged in the mixed air pipe 53. As a more preferred embodiment, the top of each stage of reaction section R3 is provided with an opening in the entire area of ​​the compression section R31 and a part of the area of ​​the expansion section R32, which is connected to the bottom of the box 51 of the mixed exhaust unit 5.

[0049] A sealing section R4 is provided between two adjacent reaction sections R3, and between the feed section R1, the discharge section R2 and the reaction section R3; a sealing sheet 31 is installed on the edge of the spiral blade 3 in the sealing section R4, and the sealing sheet 31 is attached to the inner wall of the spiral tube 1 to form a seal. As a more preferred embodiment, the length of the sealing section R4 of the spiral tube 1 is not less than the pitch of the spiral blade 3 in the sealing section R4.

[0050] The microwave generating system includes a plurality of microwave generators 6. On the outer side of the spiral tube 1 corresponding to each stage of the reaction section R3, multiple sets of microwave generators 6 are evenly arranged along the axis to emit microwaves of a specific frequency into each stage of the reaction section R3. The raw materials in the reaction section R3 can directly absorb microwave energy to heat up, or as a better embodiment, a heating ball made of microwave absorbing material is filled in the reaction section R3 inside the spiral tube 1. Usually, the heating ball is set to have a microwave absorption frequency that is the same as the microwave frequency emitted by the microwave generator. The heating ball is used to absorb microwaves to heat up the raw materials indirectly, as a main or auxiliary heat source, so that the raw material components are rapidly precipitated or decomposed. For example, the heating ball can use silicon carbide as an absorbing material, and its absorbing frequency is 12-18 GHz, preferably 15 GHz, and the corresponding microwave generator 9 can be set to transmit at a frequency of 15 GHz.

[0051] In order to better implement the above technical solution, the present invention also provides a method for pyrolyzing organic solid waste, which uses the continuous pyrolysis device provided by the present invention to pyrolyze organic solid waste, and the steps include:

[0052] S1. Turn on the rotating shaft to drive the spiral blade to rotate, and start the microwave generator to emit microwaves into each reaction section of the spiral tube;

[0053] S2. The raw material is fed into the spiral tube from the feed port, and is stirred and pushed by the spiral blades to pass through the reaction sections at each level in sequence. The raw material is heated by microwaves in each reaction section, and its components are analyzed or decomposed;

[0054] S3. The gas generated by each stage of the reaction passes through the air-permeable baffle into the corresponding mixed exhaust unit, and then is discharged through the mixed air duct for subsequent treatment and utilization;

[0055] S4. The residual carbon and waste residue left after pyrolysis of the raw materials are discharged from the spiral tube through the discharge port for subsequent treatment.

[0056] As a better implementation of the above-mentioned organic solid waste pyrolysis method, in step S2, the raw material directly absorbs microwaves to be heated and heated in each reaction section, and / or is indirectly heated and heated by absorbing microwaves through heating balls filled in each reaction section.

[0057] The following is a detailed description of the process of using a continuous pyrolysis device to pyrolyze organic solid waste raw materials through specific embodiments, and each embodiment uses a device with basically the same structure.

[0058] Example 1

[0059] The diameter of the spiral tube is 200mm; the lengths of the feeding section and the discharging section of the spiral tube are 200mm and 100mm respectively, and the length of the sealing section is 120mm; in the expansion section of the reaction section, the diameter of the rotating shaft gradually decreases from 160mm to 70mm, and in the compression section of the reaction section, the diameter of the rotating shaft gradually increases from 70mm to 160mm; the height of the mixing and exhaust unit is 200mm.

[0060] Two-stage reaction sections are arranged in the continuous pyrolysis device, with lengths of 1200 mm and 600 mm respectively, and the pitches of the internal spiral blades are 100 mm and 50 mm respectively; the corresponding mixing air ducts above the two-stage reaction sections are connected to the liquid collection system via the separation condensation system; 6 and 3 sets of microwave generators are evenly arranged on both sides of the axis of the spiral tube corresponding to the two-stage reaction sections, respectively, which can emit microwaves with frequencies of 2.5 and 15 GHz into the reaction sections; the interior of the spiral tube is filled with a heating ball made of silicon carbide, and the optimal microwave absorption frequency is 15 GHz, so that the heating ball absorbs microwaves to heat up, and the reaction temperature is maintained at 550°C and 400°C respectively by controlling the microwave power.

[0061] The waste rubber raw material with an average particle size of 10mm is fed into the continuous pyrolysis device, and is stirred and pushed by the spiral blades, and continuous pyrolysis occurs in the two-stage reaction section. First, a large amount of volatile matter is rapidly precipitated from the raw material in the first stage reaction section with a higher temperature, and then carbonization is carried out in the second stage reaction section with a lower temperature. The pyrolysis gas produced at last is separated and condensed to collect high-value liquid products, with a liquid yield of 43.6wt%, of which the target product olefin accounts for 47.2wt% in the liquid product, and the pyrolysis carbon yield is 39.4wt%, realizing the high-value utilization of waste rubber.

[0062] Example 2

[0063] The difference between this embodiment and embodiment 1 is that two reaction sections are arranged in the continuous pyrolysis device, with lengths of 600 mm and 1200 mm respectively, and the pitch of the internal spiral blades is 100 mm; the first reaction section is a dehydration zone, the temperature is maintained at 250°C, and the corresponding water vapor guide pipe is connected to the purification system; the second reaction section is a pyrolysis zone, the temperature is maintained at 500°C, and the corresponding pyrolysis gas guide pipe is connected to the liquid collection system via a separation condensation system; 3 sets and 6 sets of microwave generators are evenly arranged on both sides of the spiral tube axis of the two reaction sections respectively.

[0064] The domestic waste raw materials with an average particle size of 10mm are fed into the continuous pyrolysis device, and are stirred and pushed by the spiral blades, and continuous dehydration and pyrolysis occur in the two-stage reaction section; in the first-stage reaction section with a lower temperature, the raw materials first quickly precipitate a large amount of water, which is purified by the purification system and then discharged; then in the second-stage reaction section with a higher temperature, the raw materials are rapidly heated and pyrolyzed, and the pyrolysis gas produced is finally separated and condensed to collect the liquid phase product; the entire device curbs the emission of harmful substances such as dioxins, and the weight reduction rate reaches 82.5wt%, realizing the harmless treatment of domestic waste.

[0065] Example 3

[0066] The difference between this embodiment and embodiment 1 is that three reaction sections are arranged in the continuous pyrolysis device, with lengths of 400 mm, 600 mm and 800 mm respectively, and the pitches of the internal spiral blades are 100 mm, 80 mm and 80 mm respectively; the first reaction section is a dehydration zone, the frequency of the emitted microwaves is the characteristic frequency of moisture, and the corresponding water vapor guide pipe is connected to the purification system; the second reaction section is a holocellulose pyrolysis zone, the frequency of the emitted microwaves is the characteristic frequency of the holocellulose component, and the corresponding pyrolysis gas guide pipe is connected to the first liquid collection system via a separation and condensation system; the third reaction section is a lignin pyrolysis zone, the frequency of the emitted microwaves is the characteristic frequency of the lignin component, and the corresponding pyrolysis gas guide pipe is connected to the second liquid collection system via a separation and condensation system; 2 sets, 3 sets and 4 sets of microwave generators are evenly arranged on both sides of the axis of the spiral tubes corresponding to the three reaction sections.

[0067] Walnut shell raw materials with an average particle size of 8 mm are fed into a continuous pyrolysis device, where they are stirred and pushed by spiral blades, and continuous dehydration and pyrolysis occur in the three-stage reaction section; in the first-stage reaction section at a relatively low temperature, the raw material first rapidly precipitates a large amount of water, which is purified by a purification system and then discharged; then in the second-stage reaction section at a relatively high temperature, the holocellulose component of the raw material absorbs microwave energy and rapidly decomposes, and the generated pyrolysis gas is separated and condensed to collect liquid products rich in dehydrated sugars and furans; further in the third-stage reaction section at an even higher temperature, the remaining lignin component of the raw material absorbs microwave energy and rapidly decomposes, and the generated pyrolysis gas is separated and condensed to collect liquid products rich in phenols; the yield of the liquid products collected by the No. 2 collection system is 22.8wt%, of which the yield of the target phenolic product is 5.4wt%, thus realizing high-value utilization of walnut shell raw materials.

[0068] For the above-mentioned embodiments of the present invention, common knowledge such as the well-known specific structures and characteristics in the scheme is not described in detail; each embodiment is described in a progressive manner, and the technical features involved in each embodiment can be combined with each other under the premise that there is no conflict between each other, and the same and similar parts between the embodiments can be referred to each other.

[0069] In the description of the present invention, the terms "upper", "lower", "inner", "outer", "front", "rear", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and should not be understood as a limitation on the present invention; unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances; in addition, the terms "primary", "secondary", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0070] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as falling within the scope of protection of the present invention.

Claims

1. A continuous pyrolysis device, comprising a spiral feeding system and a microwave generating system, wherein the spiral feeding system comprises a spiral tube (1), a rotating shaft (2), spiral blades (3) and a driver (4), wherein the spiral tube (1) is a hollow circular tube arranged transversely, a feeding section (R1) is arranged at one end, a feeding port (11) for feeding raw materials is arranged at the top of the feeding section (R1), and a discharging section (R2) is arranged at the other end, and a discharging port (12) for discharging materials is arranged at the bottom of the discharging section (R2); the rotating shaft (2) is coaxially arranged in the spiral tube (1) and passes through from the feeding section (R1) to the discharging section (R2), the spiral blades (3) are continuously and fixedly arranged around the rotating shaft (2), and the driver (4) is connected to and drives the rotating shaft (2) to rotate; the microwave generating system comprises a plurality of microwave generators (6); and the characteristics are as follows: A plurality of reaction sections (R3) for raw material pyrolysis reaction are arranged between the feed section (R1) and the discharge section (R2); a sealing section (R4) is arranged between two adjacent reaction sections (R3), and between the feed section (R1), the discharge section (R2) and the reaction section (R3); wherein: The reaction section (R3) of each stage is divided into a continuous expansion section (R32) and a compression section (R31) along the raw material conveying direction, and the shaft diameter of the rotating shaft (2) gradually decreases in the expansion section (R32) and gradually increases in the compression section (R31) along the raw material conveying direction; a plurality of microwave generators (6) are arranged along the axial direction on the side of the reaction section (R3) of each stage, and are used to emit microwaves into the reaction section (R3); A sealing sheet (31) is installed on the edge of the spiral blade (3) in the sealing section (R4), and the sealing sheet (31) is attached to the inner wall of the spiral tube (1) to form a seal; A mixed exhaust unit (5) for exhausting the mixed water vapor in the reaction section (R3) is connected to the top of each reaction section (R3); Each of the mixing and exhaust units (5) comprises a hollow box (51) whose cross-sectional area gradually increases from top to bottom; the top of the box (51) is connected to a mixing air guide pipe (53); a spiral channel (531) for gas mixing is arranged in the mixing air guide pipe (53); the bottom of the box (51) is open, a permeable baffle (52) with holes is arranged at the opening; the box (51) is connected to the top of the reaction section (R3) through the bottom opening; water vapor in the reaction section (R3) enters the box (51) through the permeable baffle (52), and is mixed and discharged in the mixing air guide pipe (53); The top of each stage of the reaction section (R3) is provided with an opening in the entire area of ​​the compression section (R31) and a part of the area of ​​the expansion section (R32) so as to communicate with the bottom of the box (51) of the mixing and exhausting unit (5); The length of the sealing section (R4) of the spiral tube (1) is not less than the pitch of the spiral blade (3) in the sealing section (R4).

2. The pyrolysis device according to claim 1, characterized in that: The reaction section (R3) inside the spiral tube (1) is filled with a heating ball, and the heating ball is made of a microwave absorbing material.

3. The pyrolysis device according to claim 1 or 2, characterized in that: The spiral blade (3) is fixedly connected to a stirring rod.

4. The pyrolysis device according to claim 1 or 2, characterized in that: The inner wall of the spiral tube (1) is provided with friction patterns.

5. A pyrolysis method using the continuous pyrolysis device according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1. Turn on the rotating shaft to drive the spiral blade to rotate, and start the microwave generator to emit microwaves into each reaction section of the spiral tube; Step 2. The raw material is fed into the spiral tube from the feed port, and is stirred and pushed by the spiral blades to pass through each level of reaction section in sequence. The raw material is heated by microwaves in each level of reaction section, and its components are analyzed or decomposed; Step 3. The gas generated by each stage of the reaction passes through the air-permeable baffle and enters the corresponding mixed exhaust unit, and then is discharged through the mixed air duct for subsequent treatment and utilization; Step 4. The residual carbon and waste residue remaining after the pyrolysis of the raw materials are discharged from the spiral tube through the discharge port for subsequent treatment.

6. The pyrolysis method according to claim 5, characterized in that In step 2, the raw material is heated by absorbing microwaves directly in each reaction section, and / or is heated by absorbing microwaves indirectly through heating balls filled in each reaction section.

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