A dual-cycle heat conversion device and method

Abstract

The present invention discloses a dual-circulation thermal conversion device and method, which utilizes a circulation path consisting of a pair of spiral reactors and a pair of return pipes, continuously distributed pyrolysis zones and gasification zones, a microwave generator that utilizes heating bulbs for effective temperature control, and a guide tube that utilizes gas expansion for automatic gas discharge. The raw materials are stirred and pushed by the spiral blades and fully mixed with the heating bulbs; under the action of the microwave generator, the raw materials are heated by the heating bulbs or directly absorb microwave energy to rapidly heat up, continuously passing through the dehydration zone, pyrolysis zone, and gasification zone, and undergoing dehydration, pyrolysis, and gasification processes in sequence under optimal working conditions; the water vapor generated by the dehydration of the raw materials is further fed into the gasification zone to participate in the reaction as a partial gasifying agent, eliminating harmful components while producing high-value gasified gas; the waste residue is finally separated and discharged by the slag discharge mechanism, and the heating bulbs re-enter the circulation. This device can achieve efficient pyrolysis and gasification processes through precise temperature control.

Description

Technical Field

[0001] The present invention relates to the technical field of harmless treatment of organic solid waste, and in particular to a double-circulation thermal conversion device and method. Background Art

[0002] Thermal conversion technologies include pyrolysis and gasification, among which pyrolysis is an efficient means of 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 formation of harmful substances such as dioxins. At the same time, three products of solid, liquid and gas can be obtained, and high-value chemicals or fuels can be further prepared. As a solid product, pyrolysis carbon and semi-coke are not easy to burn. Through gasification technology, they can be further converted into high-value gasification gas, which can be used for fuel cell power generation and other methods to improve the resource utilization rate of organic solid waste. Therefore, pyrolysis and gasification are technologies with great application and promotion prospects in the current harmless disposal and high-value utilization of organic solid waste.

[0003] A spiral reactor is a highly efficient pyrolysis and gasification device that typically uses wall heating or a solid heat carrier for heat exchange. A shaft with spiral blades rotates within a closed tube wall, pushing the feedstock forward gradually, achieving continuous pyrolysis or gasification. Compared to other pyrolysis devices, such as fixed and fluidized beds, it offers advantages such as controlled stages, continuous operation, and low heat loss. To improve resource utilization and reduce energy consumption, the device typically uses low-value product combustion to provide heat for the pyrolysis or gasification process. For example, the twin-spiral pyrolysis reactors described in U.S. Patent 15922304 and Chinese Patent 202011400145.2 heat the solid heat carrier by burning pyrolysis gas or residual char in one spiral reactor, which is then fed into the other spiral reactor to provide heat for pyrolysis of the feedstock. However, simply transferring heat from the outside to the inside of the wall can easily lead to uneven temperature distribution. Even with the use of a solid heat carrier for auxiliary heat exchange, the temperature gradually decreases along the spiral reactor axis due to the gradual decrease in the heat storage capacity of the heat carrier itself, making it difficult to maintain a stable and efficient reaction. At the same time, these traditional heat transfer methods require a long heat exchange cycle, a complex device structure, and many auxiliary equipment. In addition, due to the large thermal inertia of the device, the control response is very slow, making it difficult to flexibly control the temperature according to changes in raw material components and reaction stages. It is impossible to achieve an effective combination of pyrolysis and gasification processes, which is not conducive to the promotion and application of the technology.

[0004] Therefore, it is urgent to design a new thermal conversion device that can respond and regulate in time to maintain the optimal working conditions of the pyrolysis and gasification processes while ensuring a compact structure and efficient heat transfer. Summary of the Invention

[0005] The main purpose of the present invention is to provide a dual-circulation thermal conversion device and method, which aims to solve the technical problems that the existing devices have shortcomings such as uneven heat transfer, low space utilization, and inability to respond to regulation in a timely manner, and cannot achieve efficient pyrolysis and gasification processes.

[0006] To achieve the above objectives, the present invention provides a dual-cycle heat conversion device comprising:

[0007] A first spiral reactor is arranged obliquely and has a first feeding zone, a mixing zone, a dehydration zone, a pyrolysis zone, and a first discharging zone formed therein in sequence. The spiral blades in the first spiral reactor can transport the heating balls and materials from a lower position to the first discharging zone located at a higher position. The first feeding zone can be connected to a feeding system;

[0008] A second spiral reactor is arranged obliquely and has a second feeding zone, a gasification zone, and a second discharging zone formed therein in sequence. The spiral blades in the second spiral reactor can transport the heating balls and materials from the second feeding zone at a lower position to the second discharging zone at a higher position;

[0009] a first return pipe, wherein the feed end of the first return pipe is higher than the discharge end, the first discharge zone is connected to the feed end of the first return pipe, and the discharge end of the first return pipe is connected to the second feed zone;

[0010] a second return pipe, wherein the feed end of the second return pipe is higher than the discharge end, the second discharge zone is connected to the feed end of the second return pipe, and the discharge end of the second return pipe is connected to the mixing zone; a slag discharge mechanism is provided on the second return pipe; and

[0011] In which, multiple sets of microwave generators are provided on the sides of the dehydration zone, the pyrolysis zone and the gasification zone, and the heating ball contains absorbing material, and the microwave absorption frequency of the absorbing material corresponds to the microwave frequency emitted by the microwave generator; openings are provided above the dehydration zone, the pyrolysis zone and the gasification zone, and upper air-permeable baffles are provided in the openings; the opening of the dehydration zone is connected to the water vapor guide cylinder, the opening of the pyrolysis zone is connected to the pyrolysis gas guide cylinder, and the opening of the gasification zone is connected to the gasification gas guide cylinder; a gasifying agent channel is provided below the second spiral reactor, the lower end of the gasifying agent channel can be connected to the gasifying agent supply system, and the upper end of the gasifying agent channel is connected to the gas outlet above the water vapor guide cylinder; a plurality of branch pipes are provided in the middle of the gasifying agent channel, and the branch pipes are all connected to the second spiral reactor and the branch pipes are separated from the second spiral reactor by a lower air-permeable baffle.

[0012] Optionally, the inclination angle between the first spiral reactor and the horizontal plane is α, 0<α≤60°; the inclination angle between the second spiral reactor and the horizontal plane is β, 0<β≤60°.

[0013] Optionally, a buffer is provided in the middle of the first return pipe, and the buffer is an impeller rotatably provided in the first return pipe, and the axis of the impeller is perpendicular to the extension direction of the first return pipe.

[0014] Optionally, a wear-resistant layer is formed on the surface of the heating ball.

[0015] Optionally, the first spiral reactor and the second spiral reactor each include a circular tube, a rotating shaft rotatably supported in the circular tube by a bearing, the spiral blades coiled around the rotating shaft, and a drive system disposed outside the circular tube, one end of the rotating shaft extending from an end surface of the circular tube and being transmission-connected to the drive system;

[0016] The inner circumferential surface of the circular tube is provided with friction lines, and / or the spiral blade is provided with a stirring rod or friction lines.

[0017] Optionally, cross-sections of the water vapor guide tube, the pyrolysis gas guide tube, and the gasification gas guide tube gradually decrease from bottom to top.

[0018] Optionally, the gas outlet above the pyrolysis gas guide cylinder is connected to a liquid collection system via a separation and condensation system, and the gas outlet above the gasification gas guide cylinder is connected to a gas collection system.

[0019] Furthermore, the present invention provides a pyrolysis and gasification method using the above-mentioned dual-cycle thermal conversion device, which comprises the following steps:

[0020] The drive system starts to drive the spiral blades to rotate, driving the heating ball to circulate along the process of the first spiral reactor, the first return pipe, the second spiral reactor and the second return pipe; the microwave generator starts to emit microwaves of predetermined frequency and power into the dehydration zone, the pyrolysis zone and the gasification zone respectively, and the heating ball absorbs the microwave energy and heats up, thereby maintaining the required drying temperature, pyrolysis temperature and gasification temperature respectively;

[0021] The raw materials enter the first feeding zone of the first spiral reactor through the feeding system. After being stirred and pushed by the spiral blades, they are fully mixed with the heating balls in the mixing zone and then enter the dehydration zone.

[0022] In the dehydration zone of the first spiral reactor, the raw materials are heated by heating bulbs or directly absorb microwave energy to increase temperature, remove moisture and generate water vapor; under the action of its own expansion pressure, the water vapor passes through the upper air-permeable partition, mixes in the water vapor guide cylinder, and enters the gasification agent channel;

[0023] The dehydrated raw materials continue to enter the pyrolysis zone, where they are heated up and pyrolyzed to produce pyrolysis gas. Under the action of its own expansion pressure, the pyrolysis gas passes through the upper air-permeable partition and mixes in the pyrolysis gas guide cylinder. After separation and condensation by the separation and condensation system, the liquid product is collected. The remaining carbon residue and heating balls enter the second spiral reactor through the first return pipe.

[0024] In the gasification zone of the second spiral reactor, water vapor in the gasifying agent channel and / or the gasifying agent supplied by the gasifying agent supply system mix with the pyrolyzed carbon residue to produce a gasification reaction, which then generates gasified gas. Under the action of its own expansion pressure, the gasified gas passes through the upper air-permeable baffle, is mixed with the gasified gas guide cylinder, and is then collected by the gas collection system.

[0025] The waste residue remaining after gasification enters the second return pipe, is separated from the heating balls in the slag discharge mechanism, and is discharged for subsequent treatment; the separated heating balls pass through the second return pipe and re-enter the mixing zone of the first spiral reactor to continue to participate in the circulation.

[0026] The dual-circulation thermal conversion device of the present invention utilizes a circulation path formed by a pair of spiral reactors and a pair of return pipes, continuously distributed pyrolysis and gasification zones, a microwave generator that utilizes heating bulbs for effective temperature control, and a guide tube for automatic gas discharge using gas expansion. Raw materials enter the dual-circulation thermal conversion device, where they are stirred and pushed by the spiral blades, thoroughly mixing with the heating bulbs. Under the action of the microwave generator, the raw materials are heated by the heating bulbs or directly absorb microwave energy to rapidly increase in temperature, passing through the dehydration zone, pyrolysis zone, and gasification zone, where dehydration, pyrolysis, and gasification occur sequentially under optimal operating conditions. Large amounts of gas rapidly generated in the three reaction zones are automatically discharged through the upper air-permeable baffles and corresponding guide tubes under the action of their own expansion pressure. Water vapor generated by raw material dehydration is further fed into the gasification zone, where it participates in the reaction as a partial gasifying agent, eliminating harmful components and producing high-value gasified gas. The pyrolysis gas produced by pyrolysis is separated and condensed, then collected to produce a high-value liquid product. Finally, the waste residue remaining from the pyrolysis and gasification process is separated from the heating bulbs by a slag discharge mechanism and discharged, while the heating bulbs re-enter the circulation. Due to the adoption of the above technical solution, the present invention has the following effects:

[0027] 1. Fast heating rate, energy saving and high efficiency: There is no need for heat conduction from the outside to the inside. Microwaves can penetrate the device well and directly act on the raw materials and heating balls. They are directly absorbed by the raw material molecules or absorbing materials to increase the temperature. The heating rate is fast and the thermal gradient is small, which can shorten the reaction cycle. Other structures of the device cannot absorb microwaves, so the heat loss is small and energy consumption can be saved.

[0028] 2. Good selectivity and concentrated heat: Microwaves of predetermined frequency can only be absorbed by the corresponding raw material molecules or absorbing materials. The heating range is concentrated, making it easy to control the temperature of different reaction zones, while achieving the optimal working conditions for dehydration, pyrolysis, gasification and other processes, with high reaction efficiency. In the dual-circulation thermal conversion device, high temperature is concentrated in the reaction zone, avoiding high temperature in each feeding zone, and the raw materials are not easily softened and bonded during feeding.

[0029] 3. Small thermal inertia and fast response: Microwaves of predetermined frequency can only heat the raw material molecules or the heating balls containing absorbing materials, while other structures of the device have little waste heat. Therefore, the thermal inertia is small and there is no thermal hysteresis effect. The temperature can be adjusted in time and the start and stop can be done quickly, and the state of the reaction process in different areas can be flexibly changed. Temperature compensation is performed through the heating balls to maintain a stable temperature and uniform heat transfer when the raw material composition is constantly changing.

[0030] 4. Puffing and loosening are conducive to reaction: Microwaves can directly heat the internal components of the raw materials, quickly increase the temperature to produce a large amount of gas, and form many tiny channels, which make the raw materials expand and become loose, and are not prone to adhesion or accumulation, ensuring the stable operation of the equipment and facilitating the full effect of the subsequent gasification agent.

[0031] 5. Convenient reaction control and wide adaptability to raw materials: By controlling the feed rate of the device, the circulation volume of the heating ball, the microwave emission power and frequency in different reaction zones, the speed of the rotating shaft, etc., the reaction temperature, reaction time, reaction mode and other conditions of different processes can be flexibly adjusted, thereby regulating the pyrolysis and gasification reaction according to different raw materials and the required target products to achieve efficient conversion; in addition, microwaves can penetrate into the interior of the raw materials for uniform heating, and have lower requirements on the size and shape of the raw materials. At the same time, the collision and friction of the heating ball can also continuously crush the raw materials, which can reduce the power consumption of crushing pretreatment.

[0032] 6. Clean emissions and high resource utilization: Pyrolysis is an oxygen-free process that can produce reducing components such as H2 and CO. The temperature is relatively low, which can effectively inhibit the generation of harmful substances such as dioxins from the source and achieve effective dechlorination of raw materials. At the same time, the water vapor generated in the dehydration stage of the raw materials is further used as a gasifying agent to participate in the gasification reaction of pyrolytic carbon, eliminating the harmful components carried by the dehydration process, and producing gasification gas rich in CH4, H2, CO, etc., thereby improving the resource utilization of raw materials.

[0033] 7. Automatic exhaust and safe operation: The spiral reactor has a compact space and strong pressure resistance. When water vapor, pyrolysis gas and gasification gas expand rapidly, they can directly enter the corresponding guide cylinder through the breathable partition under the push of the spiral blades to achieve automatic exhaust, instead of remaining in the spiral reactor and causing pipeline blockage and equipment damage.

[0034] 8. Compact structure and easy to seal: eliminating additional auxiliary equipment such as heat exchange, water vapor purification, and heating ball circulation. 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.

[0035] In summary, this device has the advantages of fast heating rate, concentrated heating, good selectivity, fast control response, high heat transfer efficiency, energy saving and high efficiency, good sealing, high space utilization, wide adaptability of raw materials, high resource utilization, expanded raw materials, automatic exhaust, clean emissions, etc., and can achieve efficient pyrolysis and gasification processes through precise temperature control. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0037] Figure 1 A schematic structural diagram of a dual-cycle heat conversion device provided by the present invention;

[0038] Figure 2 for Figure 1 A schematic structural diagram of the dual-cycle heat conversion device from another perspective is shown;

[0039] Figure 3 This is a partial structural diagram of a second return pipe and a slag discharge mechanism in one embodiment;

[0040] Figure 4 A schematic diagram of the partial structure of the second return pipe and the slag discharge mechanism in another embodiment;

[0041] Figure 5 This is a schematic flow chart of the pyrolysis and gasification method provided by the present invention.

[0042] Description of labels:

[0043] 1-driving system; 2-feeding system; 3-slag discharge mechanism; 31a, 31b-slag discharge pipe; 32a, 32b-screen; 4-second return pipe; 5-second spiral reactor; 6-water vapor guide tube; 7-gasification gas guide tube; 8-pyrolysis gas guide tube; 9-upper breathable baffle; 10-first return pipe; 11-buffer; 12-gasifying agent channel; 13-microwave generator; 14-first spiral reactor; 15-spiral blade; 16-heating ball; 17-rotating axis.

[0044] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in this embodiment with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] It should be noted that all directional indications in this embodiment (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0047] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referenced. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this disclosure, "plurality" means at least two, such as two or three, unless otherwise specifically defined.

[0048] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0049] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0050] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] In response to the existing problems, the present invention provides a dual-circulation thermal conversion device and method, which has the advantages of fast heating rate, concentrated heating, good selectivity, fast control response, high heat transfer efficiency, energy saving and high efficiency, good sealing, high space utilization, wide raw material adaptability, high resource utilization, expanded raw materials, automatic exhaust, clean emissions, etc., and can achieve efficient pyrolysis and gasification processes through precise temperature control.

[0052] In order to implement the above technical solution, Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a dual-circulation thermal conversion device, which includes a first spiral reactor 14, a second spiral reactor 5, a first return pipe 10 and a second return pipe 4. The first spiral reactor 14 is tilted and has a first feed zone, a mixing zone, a dehydration zone, a pyrolysis zone and a first discharge zone formed therein in sequence. The spiral blades 15 in the first spiral reactor 14 can transport the heating balls 16 and the material from a lower position to the first discharge zone located at a higher position. The heating balls 16 move from the mixing zone to the first discharge zone, and the raw materials in the material move from the first feed zone to the first discharge zone. The first feed zone can be connected to the feed system 2, wherein the feed system 2 is a known technology. The second spiral reactor 5 is tilted and has a second feed zone, a gasification zone and a second discharge zone formed therein in sequence. The spiral blades 15 in the second spiral reactor 5 can transport the heating balls 16 and the material from the lower second feed zone to the higher second discharge zone. The inclination angle between the first spiral reactor 14 and the horizontal plane is α, 0<α≤60°, preferably 5°≤α≤30°; the inclination angle between the second spiral reactor 5 and the horizontal plane is β, 0<β≤60°, preferably 5°≤β≤30°. Figure 1 and Figure 2 As can be seen from the figure, the first spiral reactor 14 and the second spiral reactor 5 are arranged in a cross-shaped manner to form an X-shaped structure to reduce space occupation.

[0053] Furthermore, the feed end of the first return pipe 10 is higher than the discharge end, and the first discharge zone is connected to the feed end of the first return pipe 10, that is, the lower opening of the first discharge zone is connected to the inlet of the first return pipe 10; the discharge end of the first return pipe 10 is connected to the second feed zone, that is, the upper opening of the second feed zone is connected to the outlet of the first return pipe 10; the feed end of the second return pipe 4 is higher than the discharge end, and the second discharge zone is connected to the feed end of the second return pipe 4, that is, the lower opening of the second discharge zone is connected to the inlet of the second return pipe 4; the discharge end of the second return pipe 4 is connected to the mixing zone, that is, the upper opening of the mixing zone is connected to the outlet of the second return pipe 4; the second return pipe 4 is provided with a slag discharge mechanism 3 for removing waste residue after pyrolysis and gasification. A pair of spiral reactors and a pair of return pipes form a circulation path to achieve the circulation of the heating ball 16 and the material. The material can include raw materials, pyrolysis carbon residue, and other materials at different processing stages.

[0054] Multiple microwave generators 13 are installed on the sides of the dehydration zone, pyrolysis zone, and gasification zone. The heating balls 16 contain an absorbing material whose microwave absorption frequency corresponds to the microwave frequency emitted by the microwave generators 13. The absorbing material can be any of silicon nitride, silicon carbide, boron nitride, aluminum nitride, graphene, and the like. For example, if the absorption frequency of a certain silicon carbide material is 12-18 GHz, with an optimal frequency of 15 GHz, the microwave generator 13's emission frequency can be set to 15 GHz. If the absorption frequency of an FeCo / graphene composite material is 7-11 GHz, with an optimal frequency of 9 GHz, the microwave generator 13's emission frequency can be set to 9 GHz. The multiple microwave generators 13 are arranged in pairs and symmetrically around the central axis of the spiral reactor to ensure uniform heating. Furthermore, the surface of the heating balls 16 is formed with a wear-resistant layer, which can be composed of boron nitride, silicon carbide, or other similar materials, to extend the service life of the heating balls 16.

[0055] A microwave generator (also known as a microwave oscillator) is an instrument that uses frequency synthesis technology to generate the required frequency or waveform signal. It is an existing known device. Frequency synthesis technology is to perform linear operations in the frequency domain on a low-frequency standard reference signal with high spectral purity and high stability generated by a crystal oscillator. Through frequency multiplication, mixing, frequency division and other technologies, one or more frequencies or frequency bands with the same stability and low phase noise that meet various indicators are obtained. From the development history of frequency synthesis, the frequency synthesis method has successively gone through the process of direct analog synthesis, phase-locked technology, and direct digital synthesis. The microwave generator 13 can emit microwaves of a predetermined frequency according to demand. The microwaves can penetrate the device well into the interior and directly heat the heating ball 16 and the material. They are directly absorbed by the raw material molecules or the absorbing material to increase the temperature. The heating rate is fast, the thermal gradient is small, and the reaction cycle can be shortened. The other structures of the device cannot absorb microwaves, so the heat loss is small, which can save energy. Moreover, microwaves of a predetermined frequency can only be absorbed by specifically corresponding raw material molecules or absorbing materials. By controlling the microwave emission power and emission time, the desired heating temperature can be flexibly controlled. The heating range is concentrated, and it is easy to control the temperature of different reaction zones, while achieving the optimal working conditions for dehydration, pyrolysis, gasification and other processes, with high reaction efficiency. In the dual-circulation thermal conversion device, high temperature is concentrated in the reaction zone, avoiding high temperature in each feed zone, and the raw materials are not easily softened and bonded during feeding.

[0056] Microwaves of a predetermined frequency only heat the raw material molecules or the heating bulb containing the absorbing material, while the remaining structures of the device produce minimal waste heat. Consequently, thermal inertia is minimal and there is no thermal hysteresis. This allows for timely temperature control and rapid start and stop operations, flexibly altering the state of the reaction process in different regions. Temperature compensation is provided through the heating bulb to maintain a stable temperature and uniform heat transfer despite the changing composition of the raw material. Microwaves directly heat the internal components of the raw material, rapidly heating it to produce a large amount of gas and forming numerous tiny pores. This causes the raw material to expand and become loose, making it less prone to sticking or accumulation, ensuring stable operation of the equipment and facilitating the full effect of the subsequent gasification agent. Furthermore, microwaves can penetrate the raw material and heat it evenly, requiring less specific size and shape. The friction of the heating bulb also continuously crushes the raw material, reducing the power consumption of the crushing pre-processing process.

[0057] In the above embodiment, the dehydration zone, pyrolysis zone, and gasification zone are each provided with an opening above, each of which is provided with an upper air-permeable baffle 9 for gas separation. The opening of the dehydration zone is connected to the water vapor guide tube 6, the opening of the pyrolysis zone is connected to the pyrolysis gas guide tube 8, and the opening of the gasification zone is connected to the gasification gas guide tube 7. A gasifying agent channel 12 is provided below the second spiral reactor 5. The lower end of the gasifying agent channel 12 can be connected to the gasifying agent supply system, and the upper end of the gasifying agent channel 12 is connected to the gas outlet above the water vapor guide tube 6. A plurality of branch pipes are provided in the middle of the gasifying agent channel 12. The branch pipes are connected from the bottom of the second spiral reactor 5 to the interior of the second spiral reactor 5, and the branch pipes are separated from the second spiral reactor 5 by a lower air-permeable baffle. The gasifying agent includes oxygen, water vapor, air, etc., and the specific gasifying agent can be determined according to the actual gasification type.

[0058] The dual-circulation thermal conversion device of the present invention utilizes a circulation path formed by a pair of spiral reactors and a pair of return pipes, continuously distributed pyrolysis and gasification zones, a microwave generator that utilizes heating bulbs for effective temperature control, and a guide tube for automatic gas discharge using gas expansion. Raw materials enter the dual-circulation thermal conversion device, where they are stirred and pushed by the spiral blades, thoroughly mixing with the heating bulbs. Under the action of the microwave generator, the raw materials are heated by the heating bulbs or directly absorb microwave energy to rapidly increase in temperature, passing through the dehydration zone, pyrolysis zone, and gasification zone, undergoing dehydration, pyrolysis, and gasification processes under optimal operating conditions. The large amounts of gas rapidly generated in the three reaction zones are automatically discharged through the upper air-permeable baffles and corresponding guide tubes under the action of their own expansion pressure. Water vapor generated by raw material dehydration is further fed into the gasification zone, where it participates in the reaction as a partial gasifying agent, eliminating harmful components while producing high-value gasified gas. The pyrolysis gas produced by pyrolysis is separated and condensed, then collected to produce a high-value liquid product. Finally, the waste residue remaining from the pyrolysis and gasification process is separated from the heating bulbs by a slag discharge mechanism and discharged, while the heating bulbs re-enter the circulation cycle.

[0059] By controlling the feed rate, the heating bulb circulation rate, the microwave power and frequency in different reaction zones, and the rotational speed of the rotating shaft, the reaction temperature, reaction time, and reaction mode can be flexibly adjusted for different processes. This allows the pyrolysis and gasification reactions to be tailored to the specific feedstock and desired target product, achieving efficient conversion. Pyrolysis is an oxygen-free process that produces reducing species such as H2 and CO. Its low temperature effectively suppresses the formation of harmful substances such as dioxins at the source, effectively dechlorinating the feedstock. Simultaneously, the water vapor generated during the dehydration stage is further utilized as a gasifying agent in the gasification of the pyrolytic carbon, eliminating harmful components carried over from the dehydration process and producing gasification gas rich in CH4, H2, and CO, thereby improving the resource utilization of the feedstock. The spiral reactor is compact and highly pressure-resistant. During rapid expansion, the water vapor, pyrolysis gas, and gasification gas are directly propelled by the spiral blades through the permeable baffles into the corresponding guide tubes for automatic exhaust, rather than remaining within the spiral reactor and causing pipe blockage and equipment damage. Eliminating the need for additional auxiliary equipment such as heat exchange, water vapor purification, and heating ball circulation, 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, resulting in a lower temperature, which helps to improve the overall sealing of the device.

[0060] In a preferred embodiment, see again Figure 1 A buffer 11 is provided in the middle of the first return pipe 10. The buffer 11 is an impeller or other similar structure that is rotatably disposed within the first return pipe 10. The axis of the buffer 11 is perpendicular to the extension direction of the first return pipe 10. The buffer 11 can be passively rotated (i.e., driven by the impact force generated by the falling heating balls 16), or actively rotated (e.g., driven by a servo motor). The buffer 11 is used to slow the descent of the heating balls 16 and evenly distribute the heating balls 16. The heating balls 16 will briefly stop when they fall on the impeller blades, and then fall one by one as the impeller rotates, continuing the cycle.

[0061] In addition, the slag discharge mechanism 3 can be in various forms, such as screening type, centrifugal type or magnetic separation type. Figure 3 The second return pipe 4 is tilted, and a slag discharge port is provided on the lower wall of the second return pipe 4; the slag discharge mechanism 3 may include a screen 32a provided in the slag discharge port and a slag discharge pipe 31a connected to the slag discharge port. The mesh diameter of the screen 32a is smaller than the diameter of the heating ball 16. The screen 32a allows the waste slag to be screened and dropped, while the heating ball 16 remains in the circulation pipe, thereby achieving separation and slag discharge. Alternatively, in other embodiments, see Figure 4The second return pipe 4 can also comprise a first vertical pipe, an inclined connecting pipe, and a second vertical pipe connected in sequence, with a slag discharge port defined on the lower wall of the inclined connecting section. The upper end of the first vertical pipe serves as the feed port, while the lower end of the second vertical pipe serves as the discharge port. The slag discharge mechanism 3 includes a screen 32b disposed within the slag discharge port and a slag discharge pipe 31b connected to the slag discharge port. The mesh size of the screen 32b is smaller than the diameter of the heating bulb 16, and the axis of the slag discharge pipe 31b is collinear with the axis of the first vertical pipe. In actual production, either slag discharge method can be selected based on demand.

[0062] See again Figure 1 and Figure 2 The first spiral reactor 14 and the second spiral reactor 5 both include a circular tube, a rotating shaft 17 supported in the circular tube by bearings, a spiral blade 15 coiled on the rotating shaft 17, and a drive system 1 arranged outside the circular tube. The circular tube and the rotating shaft 17 are coaxially arranged, one end of the rotating shaft 17 extends from the end face of the circular tube and is connected to the drive system 1 in a transmission manner. The rotating shaft 17 and the end face can be dynamically sealed by a labyrinth seal, and the other end face of the circular tube is also in a sealed state. Among them, the material of the circular tube can be non-metallic materials such as quartz and ceramics, which are strong and pressure-resistant. The feed port is opened at the top of the first feed area, and the feed port is connected to the feed system 2. The drive system 1 can be a servo motor, etc., which can drive the rotating shaft 17 to rotate around its axis and drive the spiral blade 15 to rotate, thereby pushing the heating ball 16 and the material forward. In a preferred embodiment, friction lines are also provided on the inner circumferential surface of the circular tube; and / or, a stirring rod or friction lines are provided on the spiral blade 15, the stirring rod can be a short rod with intervals formed by protruding from the surface of the structure, and the friction lines can be ridges with even intervals, etc., to enhance the stirring and mixing effect of the raw materials and the heating balls 16.

[0063] In a preferred embodiment, Figure 1 and Figure 2 As shown, the steam guide tube 6, the pyrolysis gas guide tube 8, and the vaporized gas guide tube 7 can all be hollow box-shaped structures, with their cross-sections gradually decreasing from bottom to top. That is, the bottom opening has a larger cross-sectional area to facilitate large-area collection of the corresponding gas, while the top opening is smaller to facilitate connection to the corresponding pipeline for gas transportation. Furthermore, the gas outlet above the pyrolysis gas guide tube 8 is connected to the liquid collection system via a separation and condensation system, while the gas outlet above the vaporized gas guide tube 7 is connected to the gas collection system. The gas collection system, separation and condensation system, and liquid collection system are all currently known technologies.

[0064] The following further describes the technical solution of the present invention based on the optimal embodiment. Specifically, the diameter of the first spiral reactor 14 and the second spiral reactor 5 is 200 mm, and the two are crossed and arranged at an angle of 15° to the horizontal plane to form an X-shaped structure. The first spiral reactor 14 is divided into a first feed zone, a mixing zone, a dehydration zone, a pyrolysis zone and a first discharge zone connected in sequence along the oblique upward direction, with lengths of 200 mm, 200 mm, 400 mm, 1000 mm and 200 mm respectively; the second spiral reactor 5 is divided into a second feed zone, a gasification zone and a second discharge zone connected in sequence along the oblique upward direction, with lengths of 200 mm, 1500 mm and 200 mm respectively; the first spiral reactor 14 and the second spiral reactor 5 each have a coaxially arranged rotating shaft 17 inside, and the shaft diameter is 80 mm; Two rotating shafts 17 extend from the feed end respectively and are connected to the drive system 1 outside the corresponding spiral reactor; the rotating shaft 17 is covered with spiral blades 15 with a pitch of 100 mm, and friction patterns are set on the spiral blades 15 to enhance the stirring effect; the interior of the first spiral reactor 14 and the second spiral reactor 5 is filled with heating balls 16 with a diameter of 10 mm, and the heating balls 16 are made of wear-resistant boron nitride absorbing material; the drive system 1 can drive the rotating shaft 17 to rotate around its axis, and drive the spiral blades 15 to rotate, thereby pushing the heating balls 16 and the raw materials forward.

[0065] The upper opening of the first feed zone of the first spiral reactor 14 is connected to the feed system 2, the upper opening of the mixing zone is connected to the outlet of the second return pipe 4, and the lower opening of the first discharge zone is connected to the inlet of the first return pipe 10; the upper opening of the second feed zone of the second spiral reactor 5 is connected to the outlet of the first return pipe 10, and the lower opening of the second discharge zone is connected to the inlet of the second return pipe 4; a buffer 11 is provided in the first return pipe 10 to slow down the falling of the heating balls 16 and evenly distribute the heating balls 16; a slag discharge mechanism 3 is provided in the middle of the second return pipe 4 to remove waste slag after pyrolysis and gasification and clean the heating balls 16.

[0066] The dehydration zone and the pyrolysis zone of the first spiral reactor 14 are both opened above and are connected to the steam guide tube 6 and the pyrolysis gas guide tube 8 respectively; the gasification zone of the second spiral reactor 5 is opened above and is connected to the gasification gas guide tube 7; 3 sets, 5 sets and 9 sets of microwave generators 13 are evenly arranged on both sides of the axis of the first spiral reactor 14 and the second spiral reactor 5 corresponding to the dehydration zone, the pyrolysis zone and the gasification zone respectively (see Figure 1 and Figure 2). The water vapor guide tube 6, the pyrolysis gas guide tube 8 and the gasification gas guide tube 7 are all composed of a trapezoidal hollow box, the cross-sectional diameter of the box gradually decreases from bottom to top, and the heights are 150mm, 200mm and 200mm respectively; the water vapor guide tube 6, the pyrolysis gas guide tube 8 and the gasification gas guide tube 7 are separated from the corresponding first spiral reactor 14 and the second spiral reactor 5 by an upper breathable partition 9 for gas separation. One end of the gasification agent channel 12 is connected to the gas outlet above the water vapor guide tube 6, and the other end is connected to the oxygen supply system; five branch pipes are arranged in the middle of the gasification agent channel 12 and are evenly connected to the bottom of the second spiral reactor 5, and these branch pipes are separated from the second spiral reactor 5 by a lower breathable partition; the gas outlet above the pyrolysis gas guide tube 8 is connected to the liquid collection system via the separation condensation system, and the gas outlet above the gasification gas guide tube 7 is connected to the gas collection system.

[0067] In order to better implement the above technical solution, the present invention also provides Figure 5 A pyrolysis and gasification method using a dual-cycle thermal conversion device is shown, comprising the following steps:

[0068] S1. The dual-circulation heat conversion device begins operation. The drive system starts to drive the spiral blades to rotate, driving the heating bulbs to circulate along the first spiral reactor, the first return pipe, the second spiral reactor, and the second return pipe. Simultaneously, the microwave generator starts to emit microwaves of predetermined frequency and power into the dehydration zone, the pyrolysis zone, and the gasification zone, respectively. The heating bulbs absorb the microwave energy and heat up, thereby maintaining the desired drying temperature, pyrolysis temperature, and gasification temperature, respectively.

[0069] S2, the raw material enters the first feeding zone of the first spiral reactor through the feeding system, and is stirred and pushed by the spiral blades, and is fully mixed with the heating balls in the mixing zone and then enters the dehydration zone;

[0070] S3. In the dehydration zone of the first spiral reactor, the raw materials are heated by the heating bulb or directly absorb microwave energy, and the temperature rises sharply, rapidly removing moisture and generating a large amount of water vapor. Under the action of its own expansion pressure, the water vapor passes through the upper air-permeable partition, mixes in the water vapor guide cylinder, and enters the gasification agent channel;

[0071] S4: The dehydrated raw materials continue to enter the pyrolysis zone, where they are rapidly heated and pyrolyzed, producing a large amount of pyrolysis gas. Under the action of their own expansion pressure, the pyrolysis gas passes through the upper air-permeable baffle and mixes in the pyrolysis gas guide cylinder. After separation and condensation by the separation and condensation system, the liquid product is collected. The remaining carbon residue and heating balls further enter the second spiral reactor through the first return pipe.

[0072] S5. In the gasification zone of the second spiral reactor, water vapor in the gasifying agent channel or additionally supplied gasifying agent enters from below, fully mixes with the residual carbon, and a gasification reaction occurs, rapidly producing a large amount of gasified gas. Under the action of its own expansion pressure, the gasified gas passes through the upper air-permeable baffle, is mixed in the gasified gas guide tube, and is then collected by the gas collection system.

[0073] S6. The waste residue remaining after gasification enters the second return pipe, is separated from the heating balls in the slag discharge mechanism, and is discharged for subsequent treatment; the separated heating balls further pass through the second return pipe and re-enter the mixing zone of the first spiral reactor to continue participating in the cycle.

[0074] The following describes in detail the process flow of pyrolysis and gasification of organic solid waste raw materials using a dual-circulation thermal conversion device through specific examples, and each example uses a device with basically the same structure.

[0075] Example 1

[0076] Waste sawdust raw materials with an average particle size of 8 mm are continuously fed into the dual-circulation thermal conversion device through the feeding system, stirred and pushed by the spiral blades, and fully mixed with the heating balls; under the action of the microwave generator, the raw materials directly absorb microwave energy and rapidly heat up, and the temperature is maintained with the assistance of the heating balls, continuously passing through the dehydration zone, pyrolysis zone and gasification zone, and dehydration, pyrolysis and gasification processes occur at about 250°C, about 550°C and about 900°C respectively; the generated gasification gas generates electricity in the fuel cell, providing electricity for the device, effectively achieving self-sustaining operation; the generated pyrolysis gas is separated and condensed to collect high-value liquid products, with a liquid phase yield of 47.6wt%, of which high-value phenol products account for 33.7wt% of the liquid phase products, realizing high-value utilization of waste sawdust.

[0077] Example 2

[0078] Domestic waste raw materials with an average particle size of 8mm are continuously fed into the dual-circulation thermal conversion device through the feeding system, where they are stirred and pushed by the spiral blades and fully mixed with the heating balls. Under the action of the microwave generator, the raw materials directly absorb microwave energy and rapidly heat up, and the temperature is maintained with the assistance of the heating balls. They continuously pass through the dehydration zone, pyrolysis zone and gasification zone, and dehydration, pyrolysis and gasification processes occur at approximately 250°C, approximately 500°C and approximately 900°C respectively. The generated gasification gas generates electricity in the fuel cell, providing electricity for the device and effectively achieving self-sustaining operation. The entire device curbs the emission of harmful substances such as dioxins, with a weight reduction rate of 83.4wt%, realizing the harmless treatment of domestic waste.

[0079] Example 3

[0080] Waste rubber raw materials with an average particle size of 10 mm are continuously fed into the dual-circulation thermal conversion device through the feeding system, stirred and pushed by the spiral blades, and fully mixed with the heating balls; under the action of the microwave generator, the raw materials directly absorb microwave energy and rapidly heat up, and the temperature is maintained with the assistance of the heating balls, continuously passing through the dehydration zone, pyrolysis zone and gasification zone, and dehydration, pyrolysis and gasification processes occur at about 200°C, about 550°C and about 1000°C respectively; the generated gasification gas generates electricity in the fuel cell, providing electricity for the device, effectively achieving self-sustaining operation; the generated pyrolysis gas is separated and condensed to collect high-value liquid products, with a liquid phase yield of 52.6wt%, of which the target product olefins account for 45.7wt% in the liquid phase products, realizing the harmless disposal and high-value utilization of waste rubber.

[0081] Example 4

[0082] Corn cob raw materials with an average particle size of 10 mm are continuously fed into a dual-circulation thermal conversion device through a feeding system, stirred and pushed by spiral blades, and fully mixed with heating balls. Under the action of a microwave generator, the raw materials directly absorb microwave energy and rapidly heat up, and the temperature is maintained with the assistance of heating balls. They continuously pass through a dehydration zone, a pyrolysis zone, and a gasification zone, where dehydration, pyrolysis, and gasification processes occur at approximately 200°C, approximately 550°C, and approximately 1000°C, respectively. The generated gasification gas generates electricity in a fuel cell, providing electrical energy for the device and effectively achieving self-sustaining operation, while the generated pyrolysis gas is separated and condensed to collect high-value liquid products. The final yield of the target product furfural is 8.2wt%, realizing high-value utilization of the corn cob raw materials.

[0083] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A dual-circulation heat conversion device, characterized in that: include: a first spiral reactor (14), the first spiral reactor (14) being arranged at an angle and having a first feeding zone, a mixing zone, a dehydration zone, a pyrolysis zone and a first discharging zone formed therein in sequence; the spiral blades (15) in the first spiral reactor (14) being capable of transporting the heating ball (16) and the material from a lower position to the first discharging zone located at a higher position; the first feeding zone being capable of being communicated with the feeding system (2); a second spiral reactor (5), wherein the second spiral reactor (5) is arranged obliquely and has a second feeding zone, a gasification zone, and a second discharging zone formed therein in sequence, and the spiral blades (15) in the second spiral reactor (5) are capable of transporting the heating ball (16) and the material from the second feeding zone at a lower position to the second discharging zone at a higher position; a first return pipe (10), wherein the feed end of the first return pipe (10) is higher than the discharge end, the first discharge zone is connected to the feed end of the first return pipe (10), and the discharge end of the first return pipe (10) is connected to the second feed zone; a second return pipe (4), wherein the feed end of the second return pipe (4) is higher than the discharge end, the second discharge zone is connected to the feed end of the second return pipe (4), and the discharge end of the second return pipe (4) is connected to the mixing zone; a slag discharge mechanism (3) is provided on the second return pipe (4); and The sides of the dehydration zone, the pyrolysis zone, and the gasification zone are each provided with a plurality of microwave generators (13); the heating ball (16) contains an absorbing material, and the microwave absorption frequency of the absorbing material corresponds to the microwave frequency emitted by the microwave generator (13); the tops of the dehydration zone, the pyrolysis zone, and the gasification zone are each provided with an opening, and an upper air permeable baffle (9) is provided in each opening; the opening of the dehydration zone is connected to the water vapor guide cylinder (6), the opening of the pyrolysis zone is connected to the pyrolysis gas guide cylinder (8), and the The opening of the gasification zone is connected to the gasification gas guide cylinder (7); a gasifying agent channel (12) is provided below the second spiral reactor (5); the lower end of the gasifying agent channel (12) can be connected to the gasifying agent supply system, and the upper end of the gasifying agent channel (12) is connected to the gas outlet above the water vapor guide cylinder (6); a plurality of branch pipes are provided in the middle of the gasifying agent channel (12), and the branch pipes are all connected to the second spiral reactor (5) and the branch pipes are separated from the second spiral reactor (5) by a lower air-permeable partition.

2. The dual-cycle heat conversion device according to claim 1, characterized in that: The inclination angle between the first spiral reactor (14) and the horizontal plane is α, 0<α≤60°; the inclination angle between the second spiral reactor (5) and the horizontal plane is β, 0<β≤60°.

3. The dual-cycle heat conversion device according to claim 1, characterized in that: A buffer (11) is provided in the middle of the first return pipe (10). The buffer (11) is an impeller rotatably arranged in the first return pipe (10), and the axis of the impeller is perpendicular to the extension direction of the first return pipe (10).

4. The dual-cycle heat conversion device according to any one of claims 1 to 3, characterized in that: A wear-resistant layer is formed on the surface of the heating ball (16).

5. The dual-cycle heat conversion device according to any one of claims 1 to 3, characterized in that: The first spiral reactor (14) and the second spiral reactor (5) each comprise a circular tube, a rotating shaft (17) rotatably supported in the circular tube via a bearing, the spiral blades (15) wound around the rotating shaft (17), and a drive system (1) disposed outside the circular tube, one end of the rotating shaft (17) extending from an end surface of the circular tube and being in transmission connection with the drive system (1); The inner circumferential surface of the circular tube is provided with friction lines, and / or the spiral blade (15) is provided with a stirring rod or friction lines.

6. The dual-cycle heat conversion device according to any one of claims 1 to 3, characterized in that: The cross sections of the water vapor guide tube (6), the pyrolysis gas guide tube (8), and the gasification gas guide tube (7) are gradually reduced from bottom to top.

7. The dual-cycle heat conversion device according to any one of claims 1 to 3, characterized in that: The gas outlet above the pyrolysis gas guide cylinder (8) is connected to the liquid collection system via a separation condensation system, and the gas outlet above the gasification gas guide cylinder (7) is connected to the gas collection system.

8. A pyrolysis and gasification method using the dual-cycle thermal conversion device according to any one of claims 1 to 7, characterized in that: The following steps are involved: The drive system starts to drive the spiral blades to rotate, driving the heating ball to circulate along the process of the first spiral reactor, the first return pipe, the second spiral reactor and the second return pipe; the microwave generator starts to emit microwaves of predetermined frequency and power into the dehydration zone, the pyrolysis zone and the gasification zone respectively, and the heating ball absorbs the microwave energy and heats up, thereby maintaining the required drying temperature, pyrolysis temperature and gasification temperature respectively; The raw materials enter the first feeding zone of the first spiral reactor through the feeding system. After being stirred and pushed by the spiral blades, they are fully mixed with the heating balls in the mixing zone and then enter the dehydration zone. In the dehydration zone of the first spiral reactor, the raw materials are heated by heating bulbs or directly absorb microwave energy to increase temperature, remove moisture and generate water vapor; under the action of its own expansion pressure, the water vapor passes through the upper air-permeable partition, mixes in the water vapor guide cylinder, and enters the gasification agent channel; The dehydrated raw materials continue to enter the pyrolysis zone, where they heat up and undergo pyrolysis, generating pyrolysis gas. Under the action of its own expansion pressure, the pyrolysis gas passes through the upper air-permeable baffle and mixes in the pyrolysis gas guide cylinder. After separation and condensation by the separation and condensation system, the liquid product is collected. The remaining carbon residue and heating balls enter the second spiral reactor through the first return pipe. In the gasification zone of the second spiral reactor, water vapor in the gasifying agent channel and / or the gasifying agent supplied by the gasifying agent supply system mix with the pyrolyzed carbon residue to produce a gasification reaction, which then generates gasified gas. Under the action of its own expansion pressure, the gasified gas passes through the upper air-permeable baffle, is mixed with the gasified gas guide cylinder, and is then collected by the gas collection system. The waste residue remaining after gasification enters the second return pipe, is separated from the heating balls in the slag discharge mechanism, and is discharged for subsequent treatment; the separated heating balls pass through the second return pipe and re-enter the mixing zone of the first spiral reactor to continue to participate in the circulation.

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