A multi-stage catalytic pyrolysis apparatus and method

Abstract

The application discloses a multi-stage catalytic pyrolysis device and method, which adopts a catalytic ball with an inner core heating layer and a peripheral catalytic layer, a gas passage as a necked opening, a spiral pyrolysis reactor and a multi-stage catalytic reactor. After raw materials enter, the raw materials are heated by microwaves and turned by spiral blades, rapidly heated to pyrolysis, rapidly generate a large amount of pyrolysis gas, extruded by the spiral blades, rapidly pass through a gas guide cylinder through a gas permeable partition; the pyrolysis gas is accelerated through the necked opening gas passage, and then uniformly enters the multi-stage catalytic reactor; the catalytic balls in each catalytic zone of the multi-stage catalytic reactor absorb microwaves of a predetermined frequency to maintain different required catalytic temperatures; the pyrolysis gas successively passes through the outer layer channels of the catalytic balls in different catalytic zones to continuously catalyze and react, and finally target products are obtained through further separation and condensation. The device can simultaneously realize the best working condition of different catalytic processes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic pyrolysis, in particular to a multi-stage catalytic pyrolysis device and method. BACKGROUND

[0002] Catalytic pyrolysis is a high-efficiency means for treating organic solid waste (organic solid waste) such as biomass, household garbage, waste plastics, waste rubber, etc. Compared with traditional treatment methods, it has the advantages of short treatment period, high conversion efficiency, obvious volume reduction effect, efficient heavy metal solidification, and avoidance of the generation of harmful substances such as dioxin, etc. At the same time, it can also obtain high-value solid-liquid-gas three products, and is a technology with extremely application and promotion prospects in the current harmless disposal and high-value utilization technology of organic solid waste.

[0003] For non-in-situ catalytic pyrolysis process, the generation of products may need to go through multiple steps of reaction, so it may be difficult to completely realize the directional generation of catalytic products in one step by using only one catalyst for the catalysis of pyrolysis gas. In order to more efficiently catalyze pyrolysis gas, multiple reaction furnaces in series or multiple layers of catalysts arranged in the same reaction furnace are usually used to sequentially perform different catalytic processes. For the former, such as the two-stage catalytic reaction bed described in Chinese patent 201110451218.5, the temperature and operating state of different catalytic reaction regions can be well regulated to achieve the best working conditions respectively. However, fast pyrolysis liquefaction is an unstable process, and too long catalytic process is easy to cause pyrolysis gas to deteriorate, and at the same time, in order to provide additional reaction regions, it is also inevitable to reduce space utilization and increase operating costs. For the latter, such as Chinese patent 201811484122.7, since multiple catalytic beds with different pore sizes are continuously arranged in the same reaction furnace, it is not easy to adjust the working conditions for specific catalytic processes, and it is impossible to achieve the best working conditions at the same time. In addition, traditional wall heat exchange has large heat loss and slow response to regulation, and it is difficult to make timely adjustments in response to changes in raw material components, which inevitably reduces the catalytic effect.

[0004] Therefore, it is urgent to design a new multi-stage catalytic pyrolysis reaction device to achieve the best working conditions for different catalytic processes while maintaining the compactness and high-efficiency heat transfer of the device. SUMMARY

[0005] The main purpose of the present application is to provide a multi-stage catalytic pyrolysis device and method, which aims to solve the technical problems that the existing catalytic pyrolysis device has low heat exchange efficiency, poor catalytic effect, low space utilization, etc., and cannot simultaneously achieve the best working conditions for different catalytic processes.

[0006] To achieve the above-mentioned purpose, the multi-stage catalytic pyrolysis device provided by the present application comprises:

[0007] A spiral pyrolysis reactor, an axis of rotation of a spiral blade in the spiral pyrolysis reactor extends in a horizontal direction, a middle section of the spiral pyrolysis reactor is a pyrolysis zone, a top of the pyrolysis zone is provided with a gas collection port, and a plurality of sets of first microwave generators are arranged outside the spiral pyrolysis reactor and correspond to the pyrolysis zone.

[0008] A gas guide cylinder, a cross section of the gas guide cylinder gradually decreases from a bottom to a top, the bottom of the gas guide cylinder is connected to the gas collection port, the spiral pyrolysis reactor and the gas guide cylinder are separated by a gas-permeable partition plate, and the top of the gas guide cylinder is provided with a gas passage.

[0009] A multi-stage catalytic reactor, an air inlet at a bottom of the multi-stage catalytic reactor is connected to a top of the gas passage, and a gas outlet is arranged at a top of the multi-stage catalytic reactor; a plurality of catalytic zones are sequentially arranged from bottom to top in a middle section of the multi-stage catalytic reactor, each of the catalytic zones comprises a plurality of stacked catalytic balls, and a plurality of sets of second microwave generators are arranged outside the multi-stage catalytic reactor and correspond to each of the catalytic zones.

[0010] The inner core of the catalytic ball is a heating layer, and the periphery of the catalytic ball is wrapped with a catalytic layer; the material of the catalytic layer comprises a catalytically active component, and the material of the heating layer comprises a wave-absorbing material; all the catalytic balls in the same catalytic zone correspond to the same wave-absorbing material, and the microwave absorption frequencies of the wave-absorbing materials in different catalytic zones are different; the microwave frequency generated by the second microwave generator corresponding to any catalytic zone corresponds to the microwave absorption frequency of the wave-absorbing material in the same catalytic zone.

[0011] Optionally, each of the catalytic zones comprises a support net and a plurality of catalytic balls stacked on the support net; the diameter of the air inlet of the multi-stage catalytic reactor gradually increases from bottom to top, and a gas distribution structure is arranged inside the air inlet; the gas distribution structure comprises a plurality of shunt partition plates arranged at intervals, the top end of the shunt partition plate is fixed to the bottom surface of the lowermost support net, the bottom end of the shunt partition plate faces the gas passage, and the horizontal distance between adjacent shunt partition plates gradually increases from bottom to top.

[0012] Optionally, a spiral guide vane is arranged in the gas passage.

[0013] Optionally, the spiral pyrolysis reactor comprises a cylindrical shell, the spiral blade rotatingly supported in the cylindrical shell, and a feeding motor for driving the spiral blade to rotate; a feeding port of the cylindrical shell is connected to a feeding system, and a discharging port of the cylindrical shell is connected to a discharging system; the top of the middle section of the cylindrical shell is provided with the gas collection port.

[0014] Optionally, the gas outlet is connected to a separation and condensation system.

[0015] Optionally, the catalytic layer is composed of a porous wear-resistant material loaded with catalytically active components; the catalytically active components of the catalytic balls and / or the pore types of the catalytic layer in any one of the catalytic zones are different from those of the other catalytic zones.

[0016] Optionally, the diameter of the catalytic balls is 10-100 mm.

[0017] Further, the application also provides a multi-stage catalytic pyrolysis method using the multi-stage catalytic pyrolysis device described above, which comprises the following steps:

[0018] The first microwave generator is started and emits microwaves into the spiral pyrolysis reactor, and the second microwave generator is started and emits microwaves into the multi-stage catalytic reactor, so that the catalytic balls in the catalytic zones absorb microwaves and are heated; the microwave frequency generated by the second microwave generator corresponding to any one of the catalytic zones corresponds to the microwave absorption frequency of the wave-absorbing material of the same stage.

[0019] The raw material enters the spiral pyrolysis reactor through the feeding system; under the continuous microwave heating of the first microwave generator and the stirring of the spiral blades, the raw material is heated and pyrolyzed to produce pyrolysis gas.

[0020] The pyrolysis gas passes through the gas-permeable partition plate, enters the gas guide cylinder, and then enters the gas passage; in the gas passage, the pyrolysis gas is mixed and accelerated; under the distribution of the gas uniform distribution structure, the pyrolysis gas uniformly passes through the multi-stage catalytic zones in turn and catalytically reacts with the catalytic balls.

[0021] The catalyzed pyrolysis gas is finally discharged through the gas outlet, and the liquid product is collected after separation and condensation; the remaining carbon residue is discharged through the discharging system and collected.

[0022] The multi-stage catalytic pyrolysis device in the technical scheme of the present application adopts catalytic balls with a core heating layer and a peripheral catalytic layer, a gas passage with a necked opening and an internal spiral flow guide vane, a pressure-resistant spiral pyrolysis reactor, and a multi-stage catalytic reactor. The raw material enters the spiral pyrolysis reactor and is heated by microwaves and stirred by the spiral vane, so that pyrolysis occurs with a sharp temperature rise, and a large amount of pyrolysis gas is rapidly generated. In the pressure-resistant spiral pyrolysis reactor, the pyrolysis gas expands and is extruded by the spiral vane, and then rapidly passes through the gas distribution plate into the gas guide cylinder. The pyrolysis gas passes through the necked gas passage to accelerate, and is fully mixed under the action of the internal spiral flow guide vane. Under the distribution of the gas uniform distribution structure, the pyrolysis gas then uniformly enters the multi-stage catalytic reactor. The catalytic balls in each catalytic zone of the multi-stage catalytic reactor absorb microwaves of a predetermined frequency to maintain the required different catalytic temperatures. The pyrolysis gas successively passes through the outer channels of the catalytic balls in different catalytic zones to undergo continuous catalytic reactions, and finally target products are obtained through further separation and condensation. Due to the adoption of the above technical scheme, the present application has the following effects:

[0023] 1. Fast heating rate and high energy efficiency: There is no need for heat conduction from the outside to the inside, microwaves can well penetrate the device, directly act on the raw material and catalytic balls, and be directly absorbed by the raw material molecules or wave-absorbing materials to heat up, so that the heating rate is fast, the thermal gradient is small, the reaction period can be shortened, and the energy consumption can be saved.

[0024] 2. Good selectivity and heat concentration: In the multi-stage catalytic reactor, microwaves of a predetermined frequency can only be absorbed by the corresponding wave-absorbing material, i.e. one wave-absorbing material corresponds to one microwave frequency, the heating range is concentrated, the temperature of different catalytic zones is easy to control, and the different catalytic processes can be optimized to achieve high catalytic efficiency. In the spiral pyrolysis reactor, high temperature is concentrated in the middle pyrolysis zone to avoid high temperature at the feed end, so that the raw material is not easy to soften and bond when feeding.

[0025] 3. Small thermal inertia and fast response: In the multi-stage catalytic reactor, the microwaves emitted by the second microwave generator can only heat the catalytic balls, and the residual heat of other structures in the device is small, so the thermal inertia is small, there is no thermal hysteresis effect, the catalytic temperature can be adjusted in time and started and stopped quickly, and the state of the catalytic process in different regions can be flexibly changed to adapt to the changes in the composition of the raw material.

[0026] 4. Long service life of catalyst: The temperature of different stages of the catalytic zone can be adjusted in time to avoid the catalyst working under abnormal conditions, reduce problems such as carbon deposition, and prolong the service life of the catalyst.

[0027] 5. Convenient regulation of reaction conditions: by controlling the feeding speed of the device, the microwave emission power of the pyrolysis zone and different catalytic zones, the catalytic active components of the catalytic balls, etc., the pyrolysis temperature, catalytic temperature, reaction time, and catalytic mode can be flexibly adjusted, so that the pyrolysis and catalytic reaction process can be flexibly regulated according to different raw materials and target products, and efficient conversion can be achieved.

[0028] 6. Short residence time and high space utilization: Since heat is directly transmitted to the inside of the catalytic ball by microwave, different catalytic zones are not easily affected by each other, so different catalytic zones can be arranged continuously, or the catalytic balls belonging to different catalytic zones can be directly stacked, improving the compactness of the device, thereby shortening the invalid path of the gas, ensuring timely reaction, and good catalytic effect; at the same time, additional catalytic reaction chambers and heat exchange auxiliary equipment are saved, improving the space utilization.

[0029] 7. Low requirement for raw material size and shape: The microwave energy emitted by the first microwave generator penetrates into the inside of the raw material for uniform heating, and the requirement for the size and shape of the raw material is low, which can reduce the power consumption of the crushing pretreatment.

[0030] 8. Automatic exhaust and safe operation: The spiral pyrolysis reactor is compact in space and has strong pressure resistance, and the cylindrical shell can be effectively sealed by the spiral blade to prevent gas from overflowing, so that the pyrolysis gas directly enters the gas guide cylinder through the gas permeable partition plate when it expands rapidly, realizing automatic exhaust, instead of remaining in the spiral pyrolysis reactor to cause pipeline blockage and equipment damage.

[0031] In summary, the device has the advantages of fast heating rate, concentrated heating, good selectivity, fast response to regulation, high heat transfer efficiency, energy saving and high efficiency, long service life of catalyst, avoidance of carbon deposition, high space utilization, wide adaptability of raw materials, automatic exhaust, etc., and can simultaneously realize the best working condition for different catalytic processes. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the structures shown in the drawings.

[0033] Figure 1 The structure schematic diagram of the multi-stage catalytic pyrolysis device provided by the present application;

[0034] Figure 2 The flowchart of the multi-stage catalytic pyrolysis method provided by the present application.

[0035] Label explanation:

[0036] 1 - spiral pyrolysis reactor; 2 - first microwave generator; 3 - gas guide cylinder; 4 - gas passage; 5 - multi-stage catalytic reactor; 6 - gas outlet; 7 - catalytic ball; 8 - gas distribution structure; 9 - gas-permeable partition; 10 - second microwave generator.

[0037] The purposes, functional features and advantages of the present application will be further described with reference to the embodiments in combination with the accompanying drawings. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments will be described clearly and completely below in combination with the drawings in the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0039] It should be noted that all the directionality indications (such as up, down, left, right, front, back, etc.) in the embodiments are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directionality indications also change accordingly.

[0040] In addition, the descriptions such as "first", "second" and the like in the present application are only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0041] In the present application, unless otherwise explicitly specified and limited, the terms "connection", "fixation" and the like should be understood broadly, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be direct connection, or indirect connection through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0042] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the fact that a person skilled in the art can realize it, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor is it within the scope of protection claimed by the present application.

[0043] It is to be understood that the specific embodiments described herein are merely illustrative of the present application and do not limit the present application.

[0044] The present application aims at the existing problems, and provides a multi-stage catalytic pyrolysis device and method, which has the characteristics of fast heating rate, heat concentration, good selectivity, fast response, high heat transfer efficiency, energy saving, long catalyst life, avoidance of carbon deposition, high space utilization, wide adaptability of raw materials, and automatic exhaust, etc., and can realize the best working condition of different catalytic processes while ensuring the compactness of the device.

[0045] In order to realize the above technical scheme, as shown in the accompanying drawings, Figure 1 The embodiment of the present application provides a multi-stage catalytic pyrolysis device, which comprises a spiral pyrolysis reactor 1, a gas guiding cylinder 3 and a multi-stage catalytic reactor 5. The rotation axis of the spiral blade in the spiral pyrolysis reactor 1 extends along the horizontal direction. The middle section of the spiral pyrolysis reactor 1 is a pyrolysis zone. A gas collection port is arranged at the top of the pyrolysis zone. A plurality of first microwave generators 2 are arranged outside the spiral pyrolysis reactor 1 and correspond to the pyrolysis zone. The spiral blade comprises a rotating shaft and a spiral blade coiled on the rotating shaft to realize the conveying of raw materials. Specifically, the spiral pyrolysis reactor 1 comprises a cylindrical shell arranged transversely, a spiral blade rotatably supported in the cylindrical shell, and a feeding motor (not shown) for driving the spiral blade to rotate. The cylindrical shell is coaxial with the spiral blade. The ends of the rotating shaft of the spiral blade are rotatably supported in the cylindrical shell through a pair of bearings, respectively. The material of the cylindrical shell can be a non-metallic material such as quartz or ceramic, which is solid and pressure-resistant. Both opposite end faces of the cylindrical shell are sealed. One end of the rotating shaft extends out of the end face and is drivingly connected with the feeding motor. The rotating shaft and the end face can be dynamically sealed by a labyrinth seal ring. The feeding port is arranged at the top of the end face near one end of the cylindrical shell, and the discharging port is arranged at the bottom of the end face near the other end of the cylindrical shell. The feeding port of the cylindrical shell is connected with a feeding system, and the discharging port of the cylindrical shell is connected with a discharging system. The top of the middle section of the cylindrical shell is provided with a gas collection port. The plurality of first microwave generators 2 are arranged outside the cylindrical shell and are symmetrically distributed based on the central axis of the cylindrical shell to ensure uniform heating effect.

[0046] The microwave generator (also referred to as a microwave oscillator) is an instrument for generating a required frequency or waveform signal using frequency synthesis technology, which is a known device. The frequency synthesis technology is a technology for obtaining one or more signals of a frequency or a frequency band satisfying various index requirements, such as stability and low phase noise, by performing linear operation in the frequency domain, through frequency multiplication, frequency mixing, frequency division, and the like, on a low-frequency standard reference signal having high spectral purity and high stability generated by a crystal oscillator. From the development history of frequency synthesis, the frequency synthesis method has experienced the processes of direct analog synthesis, phase-locked technology, and direct digital synthesis. The first microwave generator 2 can emit microwaves of a predetermined frequency. The microwaves can well penetrate the cylindrical shell into the interior and directly heat the raw material, the thermal gradient is small, the uniform distribution of the temperature is maintained, and the heating temperature to be reached can be flexibly controlled by controlling the emission power and the emission time of the microwaves. Moreover, the requirements for the size and shape of the raw material are low, and the power consumption of the crushing pretreatment can be reduced.

[0047] The gas guide cylinder 3 is a hollow box, the horizontal cross section of which is gradually reduced from the bottom to the top. The opening at the bottom of the gas guide cylinder 3 can be square and is connected to the gas collection port. The spiral pyrolysis reactor 1 is separated from the gas guide cylinder 3 by the gas permeable partition 9. The opening at the top of the gas guide cylinder 3 can be circular and is connected to the gas channel 4. The spiral pyrolysis reactor 1 is compact in space and has strong pressure resistance. The cylindrical shell can be effectively sealed by the spiral blade to prevent gas overflow, so that when the pyrolysis gas rapidly expands, it directly enters the gas guide cylinder 3 through the gas permeable partition 9 to realize automatic exhaust, without remaining in the spiral pyrolysis reactor 1 to cause pipeline blockage and equipment damage. Moreover, the pyrolysis gas overflowing from the gas permeable partition 9 is collected and guided by the gas guide cylinder 3, and is mixed in the tapered gas channel 4, which can make the distribution of each component in the pyrolysis gas more uniform, thereby being beneficial to the subsequent catalytic process. In addition, the spiral guide vanes can be preferably arranged in the gas channel 4 to improve the efficiency and effect of the mixing of the pyrolysis gas. The spiral guide vanes can be shaftless spiral vanes, which are fixedly arranged on the inner wall of the gas channel 4. The axis of the spiral guide vanes is collinear with the axis of the gas channel 4. The pyrolysis gas flows along the spiral guide vanes, and the airflow is accelerated and better mixed in the process of rotating flow. Moreover, the arrangement of the spiral guide vanes can shorten the length of the gas channel 4 while ensuring the mixing effect, that is, better mixing effect is achieved in the shortest possible distance, saving installation space.

[0048] The shell material at the position or path corresponding to the microwave emission of the multi-stage catalytic reactor 5 can be non-metallic material such as quartz or ceramic, so that the microwave can penetrate into the inside of the device; the gas inlet at the bottom of the multi-stage catalytic reactor 5 is in butt joint with the top of the gas channel 4, and the gas outlet 6 is arranged at the top of the multi-stage catalytic reactor 5. The middle part of the multi-stage catalytic reactor 5 is sequentially formed with multi-stage catalytic zones from bottom to top, each stage of the catalytic zones includes a plurality of stacked catalytic balls 7; a plurality of sets of second microwave generators 10 are arranged outside the multi-stage catalytic reactor 5 and correspond to each stage of the catalytic zones. Specifically, the multi-stage catalytic reactor 5 can be sequentially divided into a first-stage catalytic zone, a second-stage catalytic zone, and an Nth-stage catalytic zone from bottom to top, a plurality of sets of second microwave generators 10 are arranged outside the first-stage catalytic zone and are arranged at intervals, and the same is true for the second-stage catalytic zone and the Nth-stage catalytic zone. The second microwave generators 10 outside the first-stage catalytic zone emit first frequency microwaves, the second microwave generators 10 outside the second-stage catalytic zone emit second frequency microwaves, and the second microwave generators 10 outside the Nth-stage catalytic zone emit Nth frequency microwaves, and the microwave frequencies of the first frequency microwaves, the second frequency microwaves, and the Nth frequency microwaves are all different.

[0049] The catalytic ball 7 comprises a two-layer structure, with a heating layer as the core and a catalytic layer wrapped around the periphery. The material of the catalytic layer contains a catalytically active component, and the material of the heating layer contains a wave-absorbing material. All catalytic balls 7 in the same catalytic zone contain the same wave-absorbing material, and the microwave absorption frequencies of the wave-absorbing materials in different catalytic zones are different, i.e., different types of catalytic balls 7 are filled in different catalytic zones. The microwave frequency generated by the second microwave generator 10 corresponding to any catalytic zone corresponds to the microwave absorption frequency of the wave-absorbing material in the same catalytic zone. For example, the wave-absorbing material in the catalytic ball 7 in the first catalytic zone corresponds to absorbing only the first frequency microwave, the wave-absorbing material in the catalytic ball 7 in the second catalytic zone corresponds to absorbing only the second frequency microwave, and so on. The wave-absorbing material can be any one of silicon nitride, silicon carbide, boron nitride, aluminum nitride, graphene, etc. For example, the wave-absorbing frequency of a certain silicon carbide material is 12-18 GHz, and the best is 15 GHz, so the transmission frequency of the corresponding microwave generator can be set to 15 GHz. The wave-absorbing frequency of FeCo / graphene composite material is 7-11 GHz, and the best is 9 GHz, so the transmission frequency of the corresponding microwave generator can be set to 9 GHz. In addition, the catalytic layer is composed of a porous wear-resistant material loaded with a catalytically active component, and in the preferred embodiment, the catalytically active component of the catalytic ball 7 and / or the pore type of the catalytic layer in any catalytic zone is different from that in other catalytic zones. Here, the pore type is classified by pore size, generally less than 2 nm for micropores, greater than 50 nm for macropores, and 2-50 nm for mesopores / middle pores. The catalytically active component can be selected according to the type of catalytic reaction. The porous wear-resistant material can be various ceramics such as alumina, silicon carbide, and zirconia. The wear resistance relies on high material hardness, and the porosity relies on manufacturing process.

[0050] The above technical solution adopts a microwave heating mode, and does not need a heat conduction process from outside to inside. The microwave energy can well penetrate the device, directly acts on the raw material and the catalytic ball 7, is directly absorbed by the raw material molecules or the wave-absorbing material to be heated, the heating rate is fast, the thermal gradient is small, and the reaction period can be shortened. The device cannot absorb microwaves in other structures, and the heat loss is small, so that the energy consumption can be saved. Moreover, in the multi-stage catalytic reactor 5, microwaves of a predetermined frequency can only be absorbed by the corresponding wave-absorbing material, that is, one wave-absorbing material corresponds to one microwave frequency, the heating range is concentrated, and the temperature of different catalytic zones is easy to control, so that the different catalytic processes can be optimized, and the catalytic efficiency is high. In the spiral pyrolysis reactor 1, the high temperature is concentrated in the middle pyrolysis zone, so that the high temperature does not appear at the feeding end, and the raw material is not easy to soften and bond when feeding. In the multi-stage catalytic reactor 5, the microwaves emitted by the second microwave generator 10 can only heat the catalytic ball 7, and the heat inertia of other structures in the device is small, so that there is no thermal hysteresis effect, and the catalytic temperature can be timely adjusted and controlled, and the state of the catalytic process in different regions can be quickly started and stopped, so that the state of the catalytic process in different regions can be flexibly changed to adapt to the change of the raw material components. Moreover, by adjusting the microwave emission power of the second microwave generator 10 in different stages of the catalytic zone, the temperature of different stages of the catalytic zone can be timely adjusted, the catalyst can be prevented from working under abnormal conditions, the problems such as carbon deposition can be reduced, and the service life of the catalyst can be prolonged. More importantly, by controlling the feeding speed of the device, the microwave emission power of the pyrolysis zone and different catalytic zones, and the catalytic active components of the catalytic ball, the pyrolysis temperature, the catalytic temperature, the reaction time, and the catalytic mode can be flexibly adjusted, so that the pyrolysis and catalytic reaction processes can be flexibly adjusted according to different raw materials and target products, and high-efficiency conversion can be realized.

[0051] In order to make each stage of the catalytic zone more compact, the catalytic balls belonging to different catalytic zones can be directly stacked in order, or in other embodiments, each stage of the catalytic zone includes a support net and a plurality of catalytic balls 7 stacked on the support net, and the catalytic zone is divided by the support net. Whether the support net is arranged or not, since the heat is directly transmitted to the inside of the catalytic ball 7 through the microwave, the different catalytic zones are not easy to affect each other, so that the different catalytic zones can be continuously arranged, the invalid flow path of the gas can be shortened, the catalytic reaction can be ensured to be timely, and the catalytic effect is better; meanwhile, the additional catalytic reaction chamber and the heat exchange auxiliary equipment are omitted, and the space utilization rate is improved. The diameter of the catalytic ball 7 can be 10-100 mm, and the diameter of the catalytic ball 7 is greater than the mesh diameter of the support net.

[0052] In the preferred embodiment, referring again to Figure 1, the diameter of the gas inlet of the multi-stage catalytic reactor 5 gradually expands from bottom to top, and a gas distribution structure 8 is arranged inside, which includes multiple spaced distribution flow distribution baffles. The top end of the flow distribution baffles is fixed to the bottom surface of the lowermost support net, and the bottom end of the flow distribution baffles faces the gas passage 4. The horizontal distance between adjacent flow distribution baffles gradually expands from bottom to top. The gas distribution structure 8 can make the pyrolysis gas fully mixed in the converging-diverging gas passage 4 and uniformly dispersed to the entire horizontal cross section in the first-stage catalytic zone to ensure the catalytic effect. The flow distribution baffles can be conical cylindrical plates. Multiple conical cylindrical plates are coaxially arranged, and there is a space between adjacent conical cylindrical plates. The horizontal distance between adjacent conical cylindrical plates gradually expands from bottom to top to achieve uniform distribution of the pyrolysis gas. Alternatively, in other embodiments, the flow distribution baffles can also be flat plates. Referring to the structure in Figure 1 , the middle flat plate divides the gas inlet of the multi-stage catalytic reactor 5 into two halves, and the left and right flat plates further divide the two halves into two parts, respectively, and ensure that the horizontal distance between adjacent flat plates gradually expands from bottom to top.

[0053] The technical solutions of the application are further described based on the optimal embodiments. Specifically, the diameter of the spiral pyrolysis reactor 1 can be 200 mm, the feed inlet of the spiral pyrolysis reactor 1 is connected to the feed system, and the discharge outlet of the spiral pyrolysis reactor 1 is connected to the discharge system. The vertical upper part of the middle part of the spiral pyrolysis reactor 1 is provided with a gas collection port connected to the gas guide cylinder 3, and six sets of first microwave generators 2 are uniformly arranged on the horizontal two sides of the pyrolysis zone. The gas guide cylinder 3 is composed of a hollow box, the cross section of the box is a trapezoidal structure, the lower base length can be 1500 mm, the upper base length can be 150 mm, and the height can be 200 mm. The gas guide cylinder 3 is separated from the spiral pyrolysis reactor 1 by a gas-permeable partition 9. The upper part of the gas guide cylinder 3 is connected to the gas passage 4. The gas passage 4 can be a pipeline with a diameter of 150 mm and a height of 100 mm, and a spiral guide vane is arranged inside the pipeline for gas mixing. The upper part of the gas passage 4 is connected to the gas inlet of the multi-stage catalytic reactor 5. The cross section of the gas inlet of the multi-stage catalytic reactor 5 is also a trapezoidal structure, the lower base length can be 150 mm, the upper base length can be 800 mm, and the height can be 150 mm. Five shunt partitions are arranged inside the gas inlet of the multi-stage catalytic reactor 5 for uniform gas distribution. The multi-stage catalytic reactor 5 is divided into a first-stage catalytic zone and a second-stage catalytic zone, and the height of each stage of the catalytic zone can be 200 mm. The diameter of the catalytic ball 7 can be 10 mm, and the catalytic ball 7 is composed of two layers, including a heating layer of the core and a catalytic layer around the core. The heating layer of the catalytic ball 7 is composed of a wave-absorbing material, and the catalytic layer is composed of a porous wear-resistant material loaded with a catalytically active component. Different types of catalytic balls 7 are filled in different stages of the catalytic zone of the multi-stage catalytic reactor 5, and the catalytically active components and / or the catalytic layer pore types of the catalytic balls 7 in different stages of the catalytic zone and the microwave absorption frequency of the wave-absorbing material are different. Four sets of second microwave generators 10 are arranged on the outside of each stage of the catalytic zone of the multi-stage catalytic reactor 5. The upper part of the multi-stage catalytic reactor 5 is connected to the separation and condensation system via the gas outlet 6. The feed system, the discharge system and the separation and condensation system are all known technologies.

[0054] In order to better realize the above technical solutions, the application also provides a multi-stage catalytic pyrolysis method using a multi-stage catalytic pyrolysis device as shown in Figure 2 The steps include:

[0055] S1, the first microwave generator is started and emits microwaves into the spiral pyrolysis reactor, and the second microwave generator is started and emits microwaves of a predetermined frequency into the multi-stage catalytic reactor, wherein the microwave frequency generated by the second microwave generator corresponding to any stage of the catalytic zone corresponds to the microwave absorption frequency of the wave-absorbing material of the same stage, so that the catalytic balls in different catalytic zones absorb microwave energy and rapidly heat up, and each stage of the catalytic zone reaches the required different catalytic temperature;

[0056] S2, the raw material enters the screw pyrolysis reactor through the feeding system; under the continuous microwave heating of the first microwave generator and the turning of the screw blade, the raw material is rapidly heated to pyrolysis, and a large amount of pyrolysis gas is rapidly generated;

[0057] S3, under the self-expansion effect, the pyrolysis gas rapidly passes through the gas permeable partition plate, enters the gas guide cylinder through the gas guide cylinder, and enters the gas passage; in the gas passage, the pyrolysis gas is fully mixed and accelerated; under the distribution effect of the gas uniform distribution structure, the pyrolysis gas uniformly passes through the first-stage catalytic zone, and the catalytic reaction is carried out in the catalytic ball hole; then the pyrolysis gas successively passes through the subsequent catalytic zones of the multi-stage catalytic reactor, and different catalytic processes occur;

[0058] S4, the catalyzed pyrolysis gas is finally discharged through the gas outlet, separated and condensed through the separation and condensation system, and the liquid product is collected; the remaining carbon residue is discharged through the discharging system and collected.

[0059] The process flow of the catalytic pyrolysis of organic solid waste raw material using the multi-stage catalytic pyrolysis device is described in detail through specific examples, and the devices used in each example have basically the same structure.

[0060] Example 1

[0061] The waste rubber raw material with an average particle size of 8 mm is continuously fed into the screw pyrolysis reactor through the feeding system; by continuously absorbing microwave energy and being turned by the screw blade, the raw material is heated to about 600°C and rapidly pyrolyzes, rapidly generating a large amount of pyrolysis gas; the generated pyrolysis gas is fully mixed in the gas passage and uniformly enters the multi-stage catalytic reactor under the action of the gas uniform distribution structure. The catalytic layer of the catalytic ball in the first-stage catalytic zone is prepared using magnesium oxide, and the temperature of the first-stage catalytic zone is maintained at about 350°C by adjusting the microwave power; the catalytic layer of the catalytic ball in the second-stage catalytic zone is prepared using HZSM-5, and the temperature of the second-stage catalytic zone is maintained at about 430°C by adjusting the microwave power; the pyrolysis gas successively passes through the catalytic ball hole of the different-stage catalytic zones, and continuous catalytic reactions occur, and finally the liquid product is collected by separation and condensation; the liquid phase yield is 47.4wt%, and the target product aromatic hydrocarbon accounts for 45.8wt% in the liquid phase product, realizing the high-value utilization of the waste rubber raw material.

[0062] Example 2

[0063] The waste paper with an average particle size of 10 mm is continuously fed into the screw pyrolysis reactor through the feeding system; by continuously absorbing microwave energy and being stirred by the screw blade, the raw material is heated to about 550 DEG C and rapidly pyrolyzed, and a large amount of pyrolysis gas is rapidly generated; the generated pyrolysis gas is fully mixed through the gas channel and uniformly enters the multi-stage catalytic reactor under the action of the gas uniform distribution structure. The catalytic ball catalytic layer of the first-stage catalytic zone is prepared by using mesoporous HZSM-5, and the temperature of the first-stage catalytic zone is maintained at about 430 DEG C by adjusting the microwave power; the catalytic ball catalytic layer of the second-stage catalytic zone is prepared by using microporous HZSM-5, and the temperature of the second-stage catalytic zone is maintained at about 450 DEG C by adjusting the microwave power; the pyrolysis gas successively passes through the catalytic ball channels of different stages of the catalytic zone, and continuous catalytic reaction occurs, and finally the liquid product is collected by separation and condensation; the liquid phase yield is 44.5wt%, and the target product aromatic hydrocarbon accounts for 40.1wt% in the liquid phase product, realizing high-value utilization of the waste paper raw material.

[0064] Example 3

[0065] The rape straw with an average particle size of 8 mm is continuously fed into the screw pyrolysis reactor through the feeding system; by continuously absorbing microwave energy and being stirred by the screw blade, the raw material is heated to about 500 DEG C and rapidly pyrolyzed, and a large amount of pyrolysis gas is rapidly generated; the generated pyrolysis gas is fully mixed through the gas channel and uniformly enters the multi-stage catalytic reactor under the action of the gas uniform distribution structure. The catalytic ball catalytic layer of the first-stage catalytic zone is prepared by using HZSM-5, and the temperature of the first-stage catalytic zone is maintained at about 470 DEG C by adjusting the microwave power; the catalytic ball catalytic layer of the second-stage catalytic zone is prepared by using MCM-41, and the temperature of the second-stage catalytic zone is maintained at about 530 DEG C by adjusting the microwave power; the pyrolysis gas successively passes through the catalytic ball channels of different stages of the catalytic zone, and continuous catalytic reaction occurs, and finally the liquid product is collected by separation and condensation; the liquid phase yield is 50.2wt%, and the target product aromatic hydrocarbon accounts for 41.5wt% in the liquid phase product, realizing high-value utilization of the waste paper raw material.

[0066] The above is only the preferred embodiment of the present application, and does not limit the patent range of the present application, and any equivalent structure or equivalent flow transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, are also included in the patent protection range of the present application.

Claims

1. A multi-stage catalytic pyrolysis device, characterized in that, include: The spiral pyrolysis reactor (1) has a spiral blade whose rotation axis extends horizontally. The middle section of the spiral pyrolysis reactor (1) is a pyrolysis zone. A gas collection port is provided at the top of the pyrolysis zone. Multiple sets of first microwave generators (2) are provided outside the spiral pyrolysis reactor (1) and corresponding to the pyrolysis zone. A gas guide tube (3) has a cross-section that gradually narrows from bottom to top. The bottom of the gas guide tube (3) is connected to the gas collection port. The spiral pyrolysis reactor (1) is separated from the gas guide tube (3) by a breathable baffle (9). A vertically extending gas channel (4) is provided at the top of the gas guide tube (3). A multi-stage catalytic reactor (5) is provided, with its bottom inlet connected to the top of the gas channel (4) and a gas outlet (6) at the top. The multi-stage catalytic reactor (5) has multiple catalytic zones formed sequentially from bottom to top in its middle section, each catalytic zone comprising multiple stacked catalytic balls (7). Multiple sets of second microwave generators (10) are provided outside the multi-stage catalytic reactor (5) and corresponding to each catalytic zone. The core of the catalytic ball (7) is a heating layer and the outer layer is wrapped with a catalytic layer; the material of the catalytic layer contains catalytically active ingredients, and the material of the heating layer contains microwave absorbing material; all catalytic balls (7) in the same level of the catalytic zone contain the same microwave absorbing material, and the microwave absorption frequencies of the microwave absorbing materials in different catalytic zones are different; the microwave frequency generated by the second microwave generator (10) corresponding to any level of the catalytic zone corresponds to the microwave absorption frequency of the microwave absorbing material in the same level; Each stage of the catalytic zone includes a support net and multiple catalytic balls (7) stacked on the support net; the diameter of the inlet of the multi-stage catalytic reactor (5) gradually increases from bottom to top and is provided with a gas distribution structure (8) inside. The gas distribution structure (8) includes multiple spaced-apart baffles. The top of the baffles is fixed to the bottom surface of the bottommost support net, and the bottom of the baffles faces the gas channel (4). The horizontal spacing between adjacent baffles gradually increases from bottom to top. The gas channel (4) is equipped with spiral guide vanes.

2. The multi-stage catalytic pyrolysis apparatus according to claim 1, characterized in that, The spiral pyrolysis reactor (1) includes a cylindrical shell, spiral blades rotatably supported inside the cylindrical shell, and a feed motor for driving the spiral blades to rotate; the feed inlet of the cylindrical shell is connected to the feed system, and the discharge outlet of the cylindrical shell is connected to the discharge system; the gas collection port is provided at the top of the middle section of the cylindrical shell.

3. The multi-stage catalytic pyrolysis apparatus according to claim 1, characterized in that, The gas outlet (6) is connected to the separation and condensation system.

4. The multi-stage catalytic pyrolysis apparatus according to claim 1, characterized in that, The catalyst layer is composed of a porous wear-resistant material loaded with catalytic active components; the catalytic active components of the catalyst ball (7) in any first-level catalyst zone and / or the pore type of the catalyst layer are different from those in other catalyst zones.

5. The multi-stage catalytic pyrolysis apparatus according to claim 1, characterized in that, The diameter of the catalyst ball (7) is 10~100mm.

6. A multi-stage catalytic pyrolysis method utilizing the multi-stage catalytic pyrolysis apparatus as described in any one of claims 1-5, characterized in that, Includes the following steps: The first microwave generator is activated and emits microwaves into the spiral pyrolysis reactor. The second microwave generator is activated and emits microwaves into the multi-stage catalytic reactor, causing the catalytic balls in the catalytic zone to absorb microwaves and heat up. The microwave frequency generated by the second microwave generator in any stage of the catalytic zone corresponds to the microwave absorption frequency of the microwave absorbing material in the same stage. The raw materials enter the spiral pyrolysis reactor through the feeding system; under the continuous microwave heating of the first microwave generator and the tumbling of the spiral blades, the raw materials heat up and undergo pyrolysis to produce pyrolysis gas. The pyrolysis gas passes through the permeable baffle and enters the gas channel through the gas guide tube; in the gas channel, the pyrolysis gas is mixed and accelerated; under the distribution effect of the uniform gas distribution structure, the pyrolysis gas passes through the multi-stage catalytic zone in sequence and undergoes continuous catalytic reaction with the catalytic balls; The catalytically decomposed gas is eventually discharged through the gas outlet, and the liquid product is collected through separation and condensation; the remaining carbon residue is discharged through the discharge system and collected.

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