Rapid catalytic pyrolysis process for waste plastics

Abstract

The invention discloses a rapid catalytic pyrolysis process for waste plastics. A mixer, a downstream reactor, a cyclone dust collector, an integrated radial bed, a supergravity dust collector, a tar condensation separator and a fixed bed purification device are included; an output end of the mixer is connected with an input end pipeline of the downstream reactor, an output end of the downstream reactor is connected with an input end pipeline of the cyclone dust collector, a clean gas output end of the cyclone dust collector is connected with an input end pipeline of the integrated radial bed, and an output end of the integrated radial bed is connected with an input end pipeline of the supergravity dust collector; through the mixer, the downstream reactor, the cyclone dust collector, the integrated radial bed and the like, rapid catalytic pyrolysis of the waste plastic is achieved, the energy recovery rate is effectively increased, the waste plastic is rapidly decomposed under the action of high temperature and a catalyst, and a generated gas product is rich in energy value and can be used for power generation, heating or serving as a chemical raw material; and the dependence on native resources is obviously reduced.

Description

Technical Field

[0001] The invention relates to the field of waste plastic pyrolysis, and in particular to a process for rapid catalytic pyrolysis of waste plastic. Background Art

[0002] With the rapid development of the global economy and the continuous upgrading of consumption patterns, plastic products have been widely used in daily life and industrial production. However, this widespread application has also brought about an increasingly serious problem of plastic pollution. According to a report by the United Nations Environment Programme, less than 10% of plastic waste in the global plastic production process is effectively recycled and reused, and the vast majority of the rest is landfilled or incinerated, causing serious pollution and damage to the environment. Plastic waste decomposes very slowly in the natural environment, and harmful substances may be released during the decomposition process, causing long-term pollution to the soil, water and air.

[0003] Among the many waste plastics processing technologies, the pyrolysis process has attracted much attention because it can convert waste plastics into valuable energy products such as fuel oil and gas. However, the existing waste plastic pyrolysis process still faces many challenges in practical applications. First, the traditional pyrolysis process usually needs to be carried out under high temperature conditions, which not only leads to high energy consumption, but also may aggravate the loss and aging of equipment due to the high temperature environment. Secondly, there are many types of waste plastics and complex compositions. Different types of plastics may produce different by-products and impurities during the pyrolysis process, which will affect the purity and quality of the product. In addition, the traditional pyrolysis process also has certain shortcomings in environmental protection. For example, if the harmful gases and particulate matter that may be produced during the pyrolysis process are directly discharged into the environment without effective treatment, it will cause secondary pollution to the environment.

[0004] Therefore, it is necessary to improve a rapid catalytic pyrolysis process of waste plastics in the prior art to solve the above problems. Summary of the invention

[0005] The invention overcomes the shortcomings of the prior art and provides a rapid catalytic pyrolysis process for waste plastics.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a waste plastic rapid catalytic pyrolysis process, comprising: a mixer, a descending reactor, a cyclone dust collector, an integrated radial bed, a supergravity dust collector, a tar condensation separator and a fixed bed purification device;

[0007] The output end of the mixer is connected to the input end pipeline of the descending reactor, the output end of the descending reactor is connected to the input end pipeline of the cyclone dust collector, the clean gas output end of the cyclone dust collector is connected to the input end pipeline of the integrated radial bed, the output end of the integrated radial bed is connected to the input end pipeline of the supergravity dust collector, the output end of the supergravity dust collector is connected to the input end pipeline of the tar condensation separator, and the clean gas output end of the tar condensation separator is connected to the input end pipeline of the fixed bed purification device;

[0008] A product gas exhaust pipe is provided on one side of the fixed bed purification device, and a reflux assembly is provided between the fixed bed purification device and the mixer. The reflux assembly includes: a backfire device, a multi-flow riser and a primary separation tank. The output end of the fixed bed purification device is connected to the input end pipeline of the backfire device, and the exhaust gas output end of the cyclone dust collector is connected to the input end pipeline of the backfire device.

[0009] In a preferred embodiment of the present invention, the output end of the flashback device is connected to the input end pipeline of the multi-flow type riser, and the output end of the multi-flow type riser is connected to the input end pipeline of the primary separation tank.

[0010] In a preferred embodiment of the present invention, two output ends are provided on one side of the primary separation tank, one of the output ends of the primary separation tank is connected to the mixer input end pipeline, and the other output end pipeline of the primary separation tank is connected to the secondary separation tank, and a second ash discharge pipe is provided at the bottom of the secondary separation tank.

[0011] In a preferred embodiment of the present invention, a tar outlet pipe is provided on one side of the tar condensation separator, an air inlet pipe is provided on one side of the multi-flow type riser, and a first ash discharge pipe is provided on one side of the multi-flow type riser.

[0012] In a preferred embodiment of the present invention, a method for using a rapid catalytic pyrolysis process for waste plastics comprises the following steps:

[0013] S1: The waste plastics and the catalyst are mixed evenly in a mixer and then sent to a descending reactor to generate a high-temperature mixture containing a gas, tar and a solid mixture;

[0014] S2: The high-temperature mixture enters the cyclone dust collector to remove large dust particles, obtaining clean gas containing smaller particles and tar vapor, and part of the incompletely burned fuel tail gas is sent to the backfire device;

[0015] S3: The clean gas from the cyclone dust collector is sent to the integrated radial bed to remove tiny particles and residual pollutants, and then the clean gas is transferred to the super gravity dust collector for deep dust removal, and then the clean gas enters the tar condensation separator to condense and separate the tar, thereby obtaining high-purity gas;

[0016] S4: High-purity gas is introduced into the fixed bed purification device to remove trace harmful substances in the gas to obtain product gas, and at the same time, the solid waste that has not been completely treated in the fixed bed purification device is refluxed to the backfire device for treatment;

[0017] S5: Part of the incompletely burned fuel tail gas and the incompletely treated solid waste are fully burned in the backfire device to form ash and incompletely burned solid residues, which fall into the multi-flow type riser by gravity;

[0018] S6: The multi-flow riser pipe transports the particles upward to the primary separation tank for preliminary separation. The recyclable part is sent back to the mixer for reuse, and the non-recyclable part is introduced into the secondary separation tank for treatment and discharged through the second row of ash pipes.

[0019] In a preferred embodiment of the present invention, in S1, the mass ratio of waste plastic to catalyst is in the range of 8-12:0.8-1.2, the treatment temperature in the descending reactor is in the range of 400-600°C, the pressure range is in the range of 0.1-1MPa, and the catalytic pyrolysis time range is in the range of 1-3h.

[0020] In a preferred embodiment of the present invention, in said S2, the rotation speed of the cyclone dust collector ranges from 1000 to 2000 rpm, and the exhaust gas temperature of the cyclone dust collector after dust removal ranges from 200 to 400°C.

[0021] In a preferred embodiment of the present invention, in S3, ceramic balls are arranged in the integrated radial bed, and the mass ratio of the ceramic balls to the clean gas is 1-2:100-200, so that the dust content is less than 1-2 mg / Nm 3 The cooling temperature range of the tar condensation separator is -5--15℃, and the tar is discharged through the tar outlet pipe.

[0022] In a preferred embodiment of the present invention, in S4, the fixed bed purification device is equipped with an adsorbent and a catalyst, and the purified product gas is discharged through a product gas exhaust pipe after the temperature is controlled at 30-50°C.

[0023] In a preferred embodiment of the present invention, in said S5, the combustion treatment temperature of the flashback device ranges from 700 to 900°C, and the treatment time is 30 to 100 minutes.

[0024] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0025] (1) The present invention provides a rapid catalytic pyrolysis process for waste plastics. Through a mixer, a downward reactor, a cyclone dust collector and an integrated radial bed, etc., rapid catalytic pyrolysis of waste plastics is achieved, and the energy recovery rate is effectively improved. Waste plastics are rapidly decomposed under high temperature and catalyst action, and the generated gas products are rich in energy value and can be used for power generation, heating or as chemical raw materials, significantly reducing the dependence on primary resources. At the same time, the process also realizes the separation and recovery of tar. Tar, as a high value-added product, can be used to produce coatings, fuels or fine chemicals, further improving the efficiency of resource recycling. In addition, the incompletely burned fuel tail gas and solid residues are treated by secondary combustion through a backfire device, minimizing resource waste and environmental pollution.

[0026] (2) In the present invention, the combined use of cyclone dust collector and integrated radial bed effectively removes large dust particles and tiny particles in the gas, significantly reducing particulate matter emissions. The introduction of supergravity dust collector realizes the deep purification of residual pollutants in the gas, so that the final discharged product gas reaches an extremely high cleanliness standard. The application of tar condensation separator effectively avoids secondary pollution caused by direct emission of tar vapor. The adsorbent and catalyst in the fixed bed purification device further remove trace harmful substances in the gas, ensuring that the product gas meets environmental standards. This process improves resource recovery efficiency while achieving low pollution emissions, and has good environmental benefits.

[0027] (3) In the present invention, the incompletely burned fuel tail gas and solid residue are subjected to secondary combustion treatment through the backfire device, which not only reduces waste emissions, but also realizes energy recovery and utilization, further improving economic benefits. The recovery and utilization of by-products such as tar also creates an additional source of income for the enterprise. This process achieves higher economic benefits while ensuring environmental protection standards, and has broad market application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 is a structural diagram of the device layout of a preferred embodiment of the present invention;

[0030] Figure 2 It is a schematic structural diagram of the process of a preferred embodiment of the present invention.

[0031] In the figure: 1. mixer; 2. down-flow reactor; 3. cyclone dust collector; 4. backfire device; 5. integrated radial bed; 6. super gravity dust collector; 7. tar condensation separator; 8. fixed bed purification device; 9. multi-flow riser; 10. secondary separation tank; 11. primary separation tank. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0034] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present application. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention, unless otherwise specified, "multiple" means two or more.

[0035] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0036] like Figure 1As shown, a waste plastic rapid catalytic pyrolysis process comprises: a mixer 1, a descending reactor 2, a cyclone dust collector 3, an integrated radial bed 5, an ultra-gravity dust collector 6, a tar condensation separator 7 and a fixed bed purification device 8;

[0037] The output end of the mixer 1 is connected to the input end pipeline of the downstream reactor 2, the output end of the downstream reactor 2 is connected to the input end pipeline of the cyclone dust collector 3, the clean gas output end of the cyclone dust collector 3 is connected to the input end pipeline of the integrated radial bed 5, the output end of the integrated radial bed 5 is connected to the input end pipeline of the supergravity dust collector 6, the output end of the supergravity dust collector 6 is connected to the input end pipeline of the tar condensation separator 7, and the clean gas output end of the tar condensation separator 7 is connected to the input end pipeline of the fixed bed purification device 8.

[0038] A product gas exhaust pipe is provided on one side of the fixed bed purification device 8, and a reflux assembly is provided between the fixed bed purification device 8 and the mixer 1. The reflux assembly includes: a backfire device 4, a multi-flow riser 9 and a primary separation tank 11. The output end of the fixed bed purification device 8 is connected to the input end pipeline of the backfire device 4, and the exhaust gas output end of the cyclone dust collector 3 is connected to the input end pipeline of the backfire device 4.

[0039] The output end of the backfire device 4 is connected to the input end pipeline of the multi-flow type riser 9, and the output end of the multi-flow type riser 9 is connected to the input end pipeline of the first-level separation tank 11; one side of the first-level separation tank 11 is provided with two output ends, one output end of the first-level separation tank 11 is connected to the input end pipeline of the mixer 1, and the output end pipeline of the other first-level separation tank 11 is connected to the second-level separation tank 10, and the bottom of the second-level separation tank 10 is provided with a second row of ash pipes; one side of the tar condensation separator 7 is provided with a tar outlet pipe, one side of the multi-flow type riser 9 is provided with an air intake pipe, and one side of the multi-flow type riser 9 is provided with a first row of ash pipes.

[0040] It should be noted that: through the mixer 1, the down reactor 2, the cyclone dust collector 3, the integrated radial bed 5, the super gravity dust collector 6, the tar condensation separator 7 and the fixed bed purification device 8, etc., not only the efficient resource recovery and utilization of waste plastics are achieved, and the waste is converted into valuable energy and chemicals, but also the significant effect of environmental protection and emission reduction is ensured. The multi-stage dust removal system effectively removes the dust and particulate matter generated during the pyrolysis process, and the tar condensation separation and fixed bed purification further improve the cleanliness of the exhaust gas and reduce the pollution to the environment. It can adapt to different types and qualities of waste plastic raw materials, and the setting of the reflux component enhances the stability and adaptability of the system. In addition, the process also brings significant economic benefits. Through resource recovery and by-product utilization, it creates additional sources of income for the enterprise and reduces environmental protection costs. The concept of technological innovation and sustainable development runs through the whole process, providing strong support for the realization of resource recycling and waste reduction, harmlessness and resource utilization.

[0041] like Figure 2 As shown, a method for using a waste plastic rapid catalytic pyrolysis process comprises the following steps:

[0042] S1: waste plastics and catalysts are mixed evenly in a mixer 1 and then sent to a descending reactor 2, wherein the mass ratio of waste plastics to catalysts is in the range of 8-12:0.8-1.2, the treatment temperature in the descending reactor 2 is 400-600°C, the pressure range is 0.1-1MPa, and the catalytic pyrolysis time range is 1-3h, to generate a high-temperature mixture containing a mixture of gas, tar and solids, and the waste plastics include but are not limited to PE, PP, PS, etc.;

[0043] S2: The high-temperature mixture enters the cyclone dust collector 3 to remove large dust particles. The rotation speed of the cyclone dust collector 3 is in the range of 1000-2000rpm. The tail gas temperature of the cyclone dust collector 3 after dust removal is in the range of 200-400℃, and clean gas containing smaller particles and tar vapor is obtained. Part of the incompletely burned fuel tail gas is sent to the backfire device 4;

[0044] S3: The clean gas from the cyclone dust collector 3 is sent to the integrated radial bed 5 to remove tiny particles and residual pollutants. The integrated radial bed 5 is provided with ceramic balls. The mass ratio of the ceramic balls to the clean gas is 1-2:100-200, so that the dust content is less than 1-2 mg / Nm 3 , then the clean gas is transferred to the super gravity dust collector 6 for deep dust removal, and then the clean gas enters the tar condensation separator 7 to condense and separate the tar. The cooling temperature range of the tar condensation separator 7 is -5--15°C, and the tar is discharged through the tar outlet pipe, thereby obtaining high-purity gas;

[0045] S4: High-purity gas is introduced into the fixed bed purification device 8, which is equipped with adsorbents and catalysts to remove trace harmful substances in the gas to obtain product gas, and the adsorbents include activated carbon, molecular sieves, silica gel, alumina, etc., and the catalysts include transition metal oxide catalysts and composite catalysts, etc. At the same time, the untreated solid waste in the fixed bed purification device 8 is refluxed to the backfire device 4 for treatment, and the purified product gas is discharged through the product gas exhaust pipe after the temperature is controlled at 30-50°C;

[0046] S5: Part of the incompletely burned fuel tail gas and the incompletely treated solid waste are fully burned in the backfire device 4. The combustion treatment temperature of the backfire device 4 is in the range of 700-900°C and the treatment time is 30-100 minutes, forming ash and incompletely burned solid residues. The ash and incompletely burned solid residues fall into the multi-flow type riser 9 by gravity.

[0047] S6: The multi-flow riser 9 transports the particles upward to the primary separation tank 11 for preliminary separation. The recyclable part is returned to the mixer 1 for reuse, and the non-recyclable part is introduced into the secondary separation tank 10 for treatment and discharged through the second ash pipe.

[0048] It should be noted that:

[0049] In S1, waste plastics and catalysts are evenly mixed in mixer 1 to ensure uniform and efficient pyrolysis and improve product quality and yield. By precisely controlling mass ratio, temperature, pressure and time, product distribution is optimized and by-product generation is reduced. The high-temperature mixture generated by pyrolysis is rich in gas, tar and solids, achieving efficient conversion of waste plastics and energy recovery;

[0050] In S2, the cyclone dust collector 3 effectively removes large dust particles in the high-temperature mixture by high-speed rotation, reducing the burden on subsequent processing equipment. The exhaust gas temperature after dust removal is moderate and maintained in the range of 200-400°C, which is conducive to the smooth progress of subsequent processing steps. Part of the incompletely burned fuel exhaust gas is sent to the reburning device 4 for reprocessing, which improves energy utilization;

[0051] In S3, the integrated radial bed 5 uses ceramic balls to further remove tiny particles and residual pollutants in the gas, ensuring the cleanliness of the gas. The ultra-gravity dust collector 6 achieves deep dust removal of the gas through its unique structure and working principle, reducing the dust content to an extremely low level. The tar condensation separator 7 condenses and separates tar from the gas, improving the purity and value of the product.

[0052] In S4, the adsorbent and catalyst in the fixed bed purification device 8 effectively remove trace harmful substances in the gas, ensuring the quality and safety of the product gas. The temperature of the purified product gas is accurately controlled within the range of 30-50°C, which is conducive to subsequent use and storage. The untreated solid waste is returned to the reburning device 4 through the reflux mechanism for further treatment, thus maximizing the utilization of resources.

[0053] In S5, the high temperature environment in the backfire device 4 ensures that the incompletely burned fuel tail gas and solid waste can be fully burned to release more energy. Through full combustion, the emission of harmful substances is reduced, and the pollution to the environment is reduced. The ash and incompletely burned solid residues formed after combustion fall into the multi-flow type riser 9 by gravity, which is convenient for subsequent treatment.

[0054] In S6, the primary separation tank 11 returns the recyclable part to the mixer 1 for reuse, thus realizing the recycling of resources. The secondary separation tank 10 further processes the non-recyclable part and discharges it through the second row of ash pipes, thus ensuring the continuity and stability of the entire process. Through the multi-stage separation and recycling mechanism, the generation and emission of waste are reduced, thus meeting environmental protection requirements.

[0055] Embodiment 1:

[0056] S1: 100 kg of waste plastics and 10 kg of catalyst are uniformly mixed in mixer 1, and the mixture is sent to the descending reactor 2. The treatment temperature is set to 500°C, the pressure is set to 0.5 MPa, and the pyrolysis time is set to 2 hours. After the catalytic pyrolysis is completed, the generated high-temperature mixture is collected, which contains a mixture of gas, tar and solid.

[0057] S2: The high-temperature mixture enters the cyclone dust collector 3, and the speed is set to 1500rpm. After dust removal, the exhaust gas temperature is maintained at 300℃, large particles of dust are effectively removed, and part of the incompletely burned exhaust gas is sent to the reburning device 4 for treatment.

[0058] S3: The clean gas after cyclone dust removal enters the integrated radial bed 5 to further remove tiny particles and residual pollutants. The integrated radial bed 5 has built-in ceramic balls, the bed height is 50cm, and the mass ratio of ceramic balls to gas is set to 1:100. Then, the gas enters the supergravity dust collector 6 for deep dust removal to ensure that the dust content is less than 1mg / Nm 3 The gas enters the tar condensation separator 7, where the tar is condensed and separated at -10°C and discharged through the tar outlet pipe.

[0059] S4: High-purity gas enters the fixed bed purification device 8, and trace harmful substances are removed through the activated carbon, molecular sieve and nickel-based catalyst in the fixed bed purification device 8. The temperature of the purified product gas is controlled at 40°C and discharged through the product gas exhaust pipe. The untreated solid waste is returned to the reburning device 4 through the reflux mechanism.

[0060] S5: The incompletely burned tail gas and solid waste are fully burned at 800° C. for 30 minutes in the backfire device 4 , and the ash and incompletely burned solid residues formed after combustion fall into the multi-flow riser 9 .

[0061] S6: The multi-flow riser 9 transports the material to the primary separation tank 11, the recyclable part is sent back to the mixer 1 for reuse, and the non-recyclable part is introduced into the secondary separation tank 10, and is discharged through the second ash pipe after further treatment.

[0062] In summary, by controlling the mass ratio of waste plastics to catalysts, processing temperature, pressure and time, a highly efficient and low-byproduct catalytic pyrolysis process is achieved, which significantly improves the conversion rate of waste plastics and the quality of products; secondly, the introduction of an integrated radial bed 5 and an ultra-gravity dust collector 6 realizes multi-stage deep purification of pyrolysis gases, which not only greatly reduces the dust content, but also ensures the effective separation of tar, thereby improving the purity and market value of the product; furthermore, the adsorbent and catalyst in the fixed bed purification device 8 can comprehensively remove trace harmful substances in the gas, ensuring the safety and environmental protection standards of the product gas; in addition, the exhaust gas and solid waste backburning mechanism designed in the process not only improves the energy utilization efficiency, but also reduces the emission of harmful substances.

[0063] Moreover, by efficiently converting waste plastics into reusable resources and energy, the environmental pollution caused by urban landfill and incineration is reduced, and the urban waste treatment capacity and resource utilization level are improved. At the same time, the advanced technology and equipment used in the process reduce energy consumption and emissions, and promote urban energy conservation, emission reduction and sustainable development.

[0064] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.

Claims

1. A rapid catalytic pyrolysis process for waste plastics, comprising: A mixer (1), a descending reactor (2), a cyclone dust collector (3), an integrated radial bed (5), a supergravity dust collector (6), a tar condensation separator (7) and a fixed bed purification device (8), It is characterized by: The output end of the mixer (1) is connected to the input end pipeline of the descending reactor (2), the output end of the descending reactor (2) is connected to the input end pipeline of the cyclone dust collector (3), the clean gas output end of the cyclone dust collector (3) is connected to the input end pipeline of the integrated radial bed (5), the output end of the integrated radial bed (5) is connected to the input end pipeline of the supergravity dust collector (6), the output end of the supergravity dust collector (6) is connected to the input end pipeline of the tar condensation separator (7), and the clean gas output end of the tar condensation separator (7) is connected to the input end pipeline of the fixed bed purification device (8); A product gas exhaust pipe is provided on one side of the fixed bed purification device (8), and a reflux component is provided between the fixed bed purification device (8) and the mixer (1), wherein the reflux component comprises: a backfire device (4), a multi-flow riser (9) and a primary separation tank (11), and the output end of the fixed bed purification device (8) is connected to the input end pipeline of the backfire device (4), and the tail gas output end of the cyclone dust collector (3) is connected to the input end pipeline of the backfire device (4).

2. A rapid catalytic pyrolysis process for waste plastics according to claim 1, characterized in that: The output end of the flashback device (4) is connected to the input end pipeline of the multi-flow type riser (9), and the output end of the multi-flow type riser (9) is connected to the input end pipeline of the primary separation tank (11).

3. A rapid catalytic pyrolysis process for waste plastics according to claim 1, characterized in that: Two output ends are provided on one side of the primary separation tank (11), one of the output ends of the primary separation tank (11) is connected to a pipe at an input end of the mixer (1), and the other output end of the primary separation tank (11) is connected to a secondary separation tank (10) through a pipe, and a second ash discharge pipe is provided at the bottom of the secondary separation tank (10).

4. A rapid catalytic pyrolysis process for waste plastics according to claim 2, characterized in that: A tar outlet pipe is provided on one side of the tar condensation separator (7), an air inlet pipe is provided on one side of the multi-flow type riser (9), and a first ash discharge pipe is provided on one side of the multi-flow type riser (9).

5. A method for using a rapid catalytic pyrolysis process of waste plastics according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: waste plastics and catalysts are mixed uniformly in a mixer (1) and then sent to a descending reactor (2) to generate a high-temperature mixture containing a mixture of gas, tar and solids; S2: The high-temperature mixture enters the cyclone dust collector (3) to remove large dust particles, obtaining clean gas containing smaller particles and tar vapor, and part of the incompletely burned fuel tail gas is sent to the backfire device (4); S3: The clean gas from the cyclone dust collector (3) is sent to the integrated radial bed (5) to remove tiny particles and residual pollutants, and then the clean gas is transferred to the super gravity dust collector (6) for deep dust removal, and then the clean gas enters the tar condensation separator (7) to condense and separate the tar, thereby obtaining high-purity gas; S4: High-purity gas is introduced into the fixed bed purification device (8) to remove trace harmful substances in the gas to obtain product gas, and at the same time, the solid waste that has not been completely treated in the fixed bed purification device (8) is returned to the reburning device (4) for treatment; S5: Part of the incompletely burned fuel tail gas and the incompletely treated solid waste are fully burned in the backfire device (4) to form ash and incompletely burned solid residues, and the ash and incompletely burned solid residues fall into the multi-flow type riser (9) by gravity; S6: The multi-flow riser (9) is transported upward to the primary separation tank (11) for preliminary separation. The recoverable part is returned to the mixer (1) for reuse, and the non-recoverable part is introduced into the secondary separation tank (10) for treatment and discharged through the second ash pipe.

6. The method for using a waste plastic rapid catalytic pyrolysis process according to claim 5, characterized in that: In the S1, the mass ratio of waste plastic to catalyst is in the range of 8-12:0.8-1.2, the treatment temperature in the descending reactor (2) is in the range of 400-600°C, the pressure range is in the range of 0.1-1MPa, and the catalytic pyrolysis time range is in the range of 1-3h.

7. The method for using a waste plastic rapid catalytic pyrolysis process according to claim 5, characterized in that: In the S2, the rotation speed of the cyclone dust collector (3) is in the range of 1000-2000 rpm, and the exhaust gas temperature of the cyclone dust collector (3) after dust removal is in the range of 200-400°C.

8. The method for using a rapid catalytic pyrolysis process of waste plastics according to claim 5, characterized in that: In S3, ceramic balls are arranged in the integrated radial bed (5), and the mass ratio of the ceramic balls to the clean gas is 1-2:100-200, so that the dust content is less than 1-2 mg / Nm 3 The cooling temperature of the tar condensation separator (7) is in the range of -5 to 15°C, and the tar is discharged through the tar outlet pipe.

9. The method for using a waste plastic rapid catalytic pyrolysis process according to claim 5, characterized in that: In S4, the fixed bed purification device (8) is filled with adsorbent and catalyst, and the purified product gas is discharged through the product gas exhaust pipe after the temperature is controlled at 30-50°C.

10. The method for using a rapid catalytic pyrolysis process of waste plastics according to claim 5, characterized in that: In the step S5, the combustion treatment temperature of the flashback device (4) is in the range of 700-900°C, and the treatment time is 30-100 minutes.

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