Waste plastic catalytic cracking device and use method

Abstract

The invention discloses a waste plastic catalytic cracking device and a use method. The waste plastic catalytic cracking device comprises a three-strand impinging stream feeder, a downer reactor, a circulating fluidized bed, a backdraft device, a multi-stream riser, a primary separation tank, a secondary separation tank and a circulating pipeline which are connected in sequence, wherein the circulating pipeline is connected with the primary separation tank and the three-strand impinging stream feeder; the three-strand impinging stream feeder is provided with three feeding pipes, an impinging chamber is arranged in the three-strand impinging stream feeder, the three feeding pipes comprise a waste plastic feeding pipe, a first catalyst feeding pipe and a second catalyst feeding pipe, and catalysts are arranged in the first catalyst feeding pipe and the second catalyst feeding pipe; according to the waste plastic catalytic cracking device and the using method, the problems of low efficiency, high energy consumption, serious environmental pollution and the like in the waste plastic treatment process are solved, efficient mixing of waste plastic and a catalyst is achieved through the three impinging stream feeders, rapid cracking and conversion of the waste plastic are promoted, and the reaction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of waste plastic treatment, and in particular to a waste plastic catalytic cracking device and a use method thereof. Background Art

[0002] With the rapid expansion of the global plastics industry, plastic products have penetrated into every aspect of our lives, greatly facilitating human production and life. However, behind this prosperity lies a serious environmental challenge - the treatment and resource utilization of waste plastics are becoming increasingly prominent, becoming a major obstacle to sustainable development. According to statistics, the amount of waste plastics generated worldwide is growing exponentially each year. If not handled promptly and effectively, it will cause irreversible damage to the natural ecosystem.

[0003] Traditional methods of waste plastic disposal, such as landfill and incineration, have alleviated the pressure of waste plastic accumulation to a certain extent, but their disadvantages are also obvious. Landfill disposal requires a large amount of precious land resources, and plastics are difficult to degrade in the natural environment. Long-term accumulation may cause pollution to soil structure and groundwater. Although incineration can reduce the volume of plastics, the harmful gases and particulate matter produced in the process pose a threat to air quality. At the same time, if the heat energy generated by incineration cannot be effectively recycled, it is also a waste of energy.

[0004] In order to seek more efficient and environmentally friendly waste plastic treatment solutions, researchers are constantly exploring new technical paths. Among them, waste plastic cracking technology has attracted widespread attention because it can convert waste plastics into high-value-added chemicals or fuels. However, existing cracking technologies still face many challenges in practical applications: the cracking efficiency is affected by multiple factors such as the type of raw materials, particle size distribution, reaction conditions, etc., and it is difficult to maintain stable and efficient; there are many types of cracking products, and it is difficult to separate and purify them, resulting in low product purity, affecting the subsequent utilization value; the energy consumption during the cracking process is high, and some technologies may produce secondary pollution, such as wastewater, waste gas, etc., which require additional investment for treatment.

[0005] In addition, the imperfect separation and recovery mechanism of cracking products is also one of the bottlenecks restricting the development of technology. Many cracking technologies fail to form a closed-loop system, resulting in serious resource loss and poor economic benefits.

[0006] Therefore, it is necessary to provide a waste plastic catalytic cracking device and a method of use to solve the above technical problems. Summary of the invention

[0007] The present invention overcomes the shortcomings of the prior art and provides a waste plastic catalytic cracking device and a use method.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a waste plastic catalytic cracking device, comprising: three impinging stream feeders, a descending bed reactor, a circulating fluidized bed, a backfire device, a multi-flow type riser, a primary separation tank, a secondary separation tank, and a circulation pipeline connecting the primary separation tank and the three impinging stream feeders connected in sequence;

[0009] The three-strand impinging flow feeder is provided with three-strand feeding pipes, and the three-strand impinging flow feeder is provided with an impingement chamber, and the three-strand feeding pipes include: a waste plastic feeding pipe, a first catalyst feeding pipe and a second catalyst feeding pipe, and the first catalyst feeding pipe and the second catalyst feeding pipe are provided with catalysts;

[0010] The three feed pipes are used to respectively input waste plastics, a first catalyst and a second catalyst into the impact chamber, and the catalyst is a Fe-Zr / ZSM-5 catalyst.

[0011] In a preferred embodiment of the present invention, the down-flow bed reactor is used to receive the mixed materials for reaction, and a static fluid changing structure is provided inside the down-flow bed reactor.

[0012] In a preferred embodiment of the present invention, the impact chamber is used to achieve impact mixing of materials, and an impact angle and an impact surface are provided in the impact chamber.

[0013] In a preferred embodiment of the present invention, the static fluid changing structure comprises: multiple layers of staggered baffles.

[0014] In a preferred embodiment of the present invention, both the primary separation tank and the secondary separation tank are provided with a filter layer.

[0015] In a preferred embodiment of the present invention, an ash discharge pipe is provided at the bottom of the secondary separation tank.

[0016] A method for using a waste plastic catalytic cracking device based on any one of the above items comprises the following steps:

[0017] S1: At a temperature of 15-25°C, waste plastics and catalysts are fed into a three-stream impinging stream feeder at a total feed rate of 500 g / min to form a mixed material;

[0018] S2: Entering the descending bed reactor, the mixed material reacts for 25-35 minutes under the action of the static fluid structure, and the reaction temperature is 350-450℃;

[0019] S3: Entering the circulating fluidized bed for treatment, the combustible gas is sent to the backfire device for combustion;

[0020] S: transported upward through a multi-flow riser to the primary separation tank for preliminary separation;

[0021] S: The recyclable part is sent back to the three-stream impinging stream feeder for reuse, and the non-recyclable part is introduced into the secondary separation tank for treatment and discharged through the ash discharge pipe.

[0022] In a preferred embodiment of the present invention, in S1, the mass ratio of waste plastics to catalyst is in the range of 1-3:1-3, and the mixing time is in the range of 5-10 min.

[0023] In a preferred embodiment of the present invention, in S3, the temperature range of the circulating fluidized bed is 250-350°C, the processing time is 30-40 minutes, the temperature range of the backfire device is 800-1000°C, and the combustion time is 5-15 minutes.

[0024] In a preferred embodiment of the present invention, in S5, the processing temperature of the primary separation tank and the secondary separation tank is 25-30°C.

[0025] The present invention solves the defects existing in the background technology and has the following beneficial effects:

[0026] (1) The present invention provides a waste plastic catalytic cracking device and a method of use. The present invention solves the problems of low efficiency, high energy consumption, and serious environmental pollution in the waste plastic treatment process. A three-stream impact flow feeder is used to achieve efficient mixing of waste plastic and catalyst, thereby promoting rapid cracking and conversion of waste plastic and improving reaction efficiency. The multi-stage separation tank design is used to achieve fine separation and recycling of reaction products, thereby improving product purity and recovery rate, while reducing waste generation and environmental pollution.

[0027] (2) The present invention adopts a three-stream impinging flow feeder, which is provided with a waste plastic feed pipe, a first catalyst feed pipe and a second catalyst feed pipe. An impingement angle and an impingement surface are provided in the impingement chamber to ensure that the materials are fully mixed. The impinging flow technology utilizes the turbulence effect generated by high-speed impact to make the materials reach a highly mixed state in a short time, which is conducive to the full contact between the catalyst and the waste plastic, thereby accelerating the reaction process. The mixing efficiency of the waste plastic and the catalyst is significantly improved, the reaction time is shortened, and the energy consumption is reduced. Compared with traditional stirring or mixing methods, the impinging flow technology has higher mixing efficiency and lower energy consumption, and can more effectively promote the cracking and conversion of waste plastics. Due to the improvement of reaction efficiency, the overall processing capacity of the system is enhanced, and a larger amount of waste plastics can be processed. At the same time, the by-products generated by incomplete reaction are reduced, and the quality and market value of the product are improved.

[0028] (3) In the present invention, the primary separation tank and the secondary separation tank are both equipped with a filter layer for achieving fine separation of the reaction products. At the same time, an ash discharge pipe is provided at the bottom of the secondary separation tank to facilitate the treatment of the non-recyclable part. The design of the multi-stage separation tank can gradually remove impurities and unreacted products in the product, thereby improving the purity of the product. The selective filtering effect of the filter layer ensures that only products that meet the requirements can pass through, while the ash discharge pipe effectively treats waste that cannot be reused; significantly improves the purity and recovery rate of the product, reduces waste generation, and reduces environmental pollution; compared with a single separation or simple filtration method, the design of the multi-stage separation tank is more sophisticated and efficient, and can more thoroughly separate the target product while reducing the negative impact on the environment; due to the improvement in product purity, the subsequent processing process is simpler and more efficient, reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] 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.

[0030] Figure 1 It is a structural schematic diagram of a preferred embodiment of the present invention;

[0031] Figure 2 It is a schematic diagram of a preferred embodiment of the present invention;

[0032] Figure 3 This is the design idea of ​​the Fe-Zr / ZSM-5 catalyst of the preferred embodiment of the present invention;

[0033] In the figure: 1. Three-stream impinging flow feeder; 2. Downward bed reactor; 3. Circulating fluidized bed; 4. Backfire device; 5. Multi-flow riser; 6. Primary separation tank; 7. Secondary separation tank. DETAILED DESCRIPTION

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] like Figure 1 and Figure 3 As shown, the present invention provides a waste plastic catalytic cracking device, comprising: a three-stream impinging flow feeder 1, a downer reactor 2, a circulating fluidized bed 3, a backfire device 4, a multi-flow type riser 5, a primary separation tank 6, a secondary separation tank 7, and a circulation pipeline connecting the primary separation tank 6 and the three-stream impinging flow feeder 1, wherein:

[0039] The three-strand impinging stream feeder 1 is provided with three-strand feeding pipes, and the three-strand impinging stream feeder 1 is provided with an impingement chamber, and the three-strand feeding pipes include: a waste plastic feeding pipe, a first catalyst feeding pipe and a second catalyst feeding pipe, and the first catalyst feeding pipe and the second catalyst feeding pipe are provided with catalysts;

[0040] The three feed pipes are used to respectively input waste plastics, a first catalyst and a second catalyst into the impact chamber, and the catalyst is a Fe-Zr / ZSM-5 catalyst.

[0041] The down-going bed reactor 2 is used to receive the mixed materials for reaction, and a static fluid changing structure is arranged inside the down-going bed reactor 2; the impact chamber is used to realize the impact mixing of the materials, and an impact angle and an impact surface are arranged in the impact chamber, and the static fluid changing structure includes: multiple layers of staggered baffles, and both the primary separation tank 5 and the secondary separation tank 6 are provided with filtering layers; and an ash discharge pipe is arranged at the bottom of the secondary separation tank 6.

[0042] It should be noted that:

[0043] The core of the multi-component reaction and separation system provided by the present invention lies in the design of three impinging stream feeders, which realizes efficient impinging mixing of waste plastics and Fe-Zr / ZSM-5 catalysts. The Fe-Zr / ZSM-5 catalyst effectively promotes the cracking reaction of waste plastics with its excellent catalytic activity and selectivity, generating high-value cracking products. At the same time, the static fluid-changing structure in the down-flowing bed reactor, such as the multi-layer staggered baffles, further enhances the mass transfer and heat transfer efficiency between the material and the catalyst, and improves the effect of the cracking reaction. This efficient mixing and reaction mechanism not only shortens the reaction time, but also improves the reaction efficiency and product quality, laying a solid foundation for the resource utilization of waste plastics.

[0044] In addition to the efficient mixed reaction mechanism, another highlight of the present invention is its multi-stage separation and recovery system. The primary separation tank and the secondary separation tank perform fine separation of the cracking products through the filter layer, which effectively improves the purity and recovery rate of the target product. In particular, the ash discharge pipe design at the bottom of the secondary separation tank facilitates the regular cleaning of solid residues and ensures the continuous and stable operation of the system. In addition, the circulation pipeline connecting the primary separation tank and the three-strand impact flow feeder realizes the recycling of incompletely reacted materials or catalysts, improves resource utilization, and reduces waste emissions. This series of designs not only reduces production costs, but also conforms to the concepts of green chemistry and sustainable development, and contributes to the cause of environmental protection.

[0045] As a heat carrier and catalyst for rapid pyrolysis of organic solid waste, Fe-Zr / ZSM-5 catalyst has moderate acidity, fast mass transfer and diffusion rates, and certain shape selectivity. Compared with thermal cracking, the liquid yield is increased by 10-25%, and the selectivity of C5-C12 light components in pyrolysis oil and gas is increased by ≥50%. The catalyst can be efficiently regenerated during the riser burnout process. After 100 cycles of use, there is no obvious attenuation of catalytic performance. The loss caused by the discharge of fine powder produced by wear during a single cycle is ≤0.1%, and the catalyst cost is less than 30,000 yuan / ton.

[0046] like Figure 2-Figure 3 As shown, a method for using a waste plastic catalytic cracking device comprises the following steps:

[0047] S1: at a temperature of 15-25° C., waste plastics and catalysts are fed into a three-stream impinging stream feeder 1 at a total feed rate of 500 g / min to form a mixed material, wherein the mass ratio of waste plastics to catalysts is in the range of 1-3:1-3, and the mixing time is in the range of 5-10 min;

[0048] S2: Entering the descending bed reactor 2, the mixed material reacts for 25-35 minutes under the action of the static fluid structure, and the reaction temperature is 350-450°C;

[0049] S3: Entering the circulating fluidized bed 3 for treatment, the combustible gas is sent to the backfire device 4 for combustion, the temperature range of the circulating fluidized bed 3 is 250-350°C, the treatment time is 30-40min, the temperature range of the backfire device 4 is 800-1000°C, and the combustion time is 5-15min;

[0050] S4: transported upward through the multi-flow riser 5 to the primary separation tank 6 for preliminary separation;

[0051] S5: The recyclable part is sent back to the three-stream impinging flow feeder 1 for reuse, and the non-recyclable part is introduced into the secondary separation tank 7 for treatment and discharged through the ash discharge pipe. The treatment temperature of the primary separation tank 6 and the secondary separation tank 7 is 25-30°C.

[0052] It should be noted that:

[0053] In step S1, the uniform mixing of the mixed materials in the three-stream impact stream feeder is ensured by precisely controlling the feed temperature (15-25°C) and feed rate (500g / min), combined with the appropriate mass ratio of waste plastics to catalysts (1-3:1-3). A good mixing effect can be achieved within a short mixing time (5-10min), laying the foundation for subsequent efficient reactions. The waste plastic is polyethylene (PE) as the experimental raw material, and its particle size is controlled at 5-10mm.

[0054] In step S2, the mixed material reacts in the down-flow reactor at a suitable reaction temperature (350-450°C) and time (25-35min) under the action of the static fluid structure. This design effectively promotes the cracking of waste plastics, improves reaction efficiency and product quality. Polyethylene (PE) is used as the experimental raw material, and its particle size is controlled at 5-10mm to ensure smooth feeding.

[0055] In step S3, the circulating fluidized bed performs preliminary treatment on the combustible gas produced by cracking, and then sends it to the high-temperature backfire device (800-1000°C) for full combustion, and the combustion time is controlled within 5-15 minutes. This not only reduces the emission of harmful gases, but also recovers heat energy and improves energy utilization.

[0056] In step S4, the reaction products are transported to the primary separation tank through the multi-flow riser for preliminary separation, and then the recyclable part is sent back to the three-stream impingement flow feeder for reuse, thus maximizing the utilization of resources. The secondary separation tank further processes the non-recyclable part and discharges it safely through the ash discharge pipe, thus avoiding environmental pollution.

[0057] In step S5, the primary and secondary separation tanks are operated at a relatively low temperature (25-30°C), which not only protects the separation materials from high temperature damage, but also prolongs the service life of the equipment while ensuring the stability and reliability of the separation effect.

[0058] The entire system process works together to achieve efficient control of the entire process from waste plastic pretreatment, catalytic cracking, gas treatment to product separation. By precisely controlling the operating conditions and parameters of each step, energy consumption and production costs are significantly reduced, and overall economic benefits are improved.

[0059] Embodiment 1:

[0060] S1: Weigh appropriate amounts of raw materials and catalysts according to the mass ratio of waste plastics to catalysts of 1:1. Waste plastics: polyethylene (PE) is selected as the experimental raw material with a particle size of 8 mm. At room temperature of 20°C, waste plastics and catalysts are simultaneously fed into the waste plastics feed pipe, the first catalyst feed pipe and the second catalyst feed pipe of the three-stream impact flow feeder at a total feed rate of 500 g / min. The mixing time is controlled to be 8 minutes to ensure that the materials are fully mixed in the impact chamber.

[0061] S2: The mixed materials enter the descending bed reactor and react under the action of the static fluid structure. The reaction temperature is set to 400℃ and the reaction time is 30min. In this stage, the waste plastics undergo cracking reaction under the action of the catalyst to generate cracking products;

[0062] S3: The combustible gas produced by cracking enters the circulating fluidized bed for preliminary treatment and is then sent to the backfire device. The temperature of the circulating fluidized bed is set at 300°C and the treatment time is 35 minutes. The temperature of the backfire device is controlled at 900°C and the combustion time is 10 minutes to ensure that the combustible gas is completely burned and reduce harmful emissions.

[0063] S4: The cracking products are transported to the primary separation tank through a multi-flow riser for preliminary separation;

[0064] S5: The treatment temperature of the primary separation tank is set to 28°C, and the recyclable part (hydrocarbon compounds) is sent back to the three-stream impingement flow feeder through the circulation pipeline for reuse; the non-recyclable part (solid residue) is introduced into the secondary separation tank for further treatment. The treatment temperature of the secondary separation tank is also set to 28°C, and finally it is safely discharged through the ash discharge pipe.

[0065] In general, multiple goals such as efficient cracking and conversion, environmental protection and emission reduction, efficient resource utilization, and stable and reliable process are achieved in the treatment of waste plastics. Through the precise mixing of the three-stream impact flow feeder and the optimization of the static fluid structure in the down-flow bed reactor, the waste plastics are rapidly cracked with the help of the catalyst to generate rich cracking products. At the same time, the circulating fluidized bed and the backfire device in the system work together to ensure the complete combustion of the combustible gas and greatly reduce harmful emissions. In addition, the recyclable part of the cracking product is effectively separated and sent back to the feeder for reuse, which not only reduces production costs, but also promotes the maximum utilization of resources. The entire processing flow is reasonably designed, and the components work together efficiently, ensuring the stability and reliability of the process, providing an economical, environmentally friendly and efficient solution for the resource utilization of waste plastics.

[0066] 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 waste plastic catalytic cracking device, characterized in that: include: A three-stream impinging flow feeder (1), a descending bed reactor (2), a circulating fluidized bed (3), a backfire device (4), a multi-flow type riser (5), a primary separation tank (6), a secondary separation tank (7), and a circulation pipeline connecting the primary separation tank (6) and the three-stream impinging flow feeder (1) connected in sequence; The three-strand impinging stream feeder (1) is provided with three-strand feeding pipes, and the three-strand impinging stream feeder (1) is provided with an impingement chamber, and the three-strand feeding pipes include: a waste plastic feeding pipe, a first catalyst feeding pipe and a second catalyst feeding pipe, and the first catalyst feeding pipe and the second catalyst feeding pipe are provided with catalysts; The three feed pipes are used to respectively input waste plastics, a first catalyst and a second catalyst into the impact chamber, and the catalyst is a Fe-Zr / ZSM-5 catalyst.

2. A waste plastic catalytic cracking device according to claim 1, characterized in that: The down-flow bed reactor (2) is used to receive the mixed materials for reaction, and a static fluid changing structure is provided inside the down-flow bed reactor (2).

3. A waste plastic catalytic cracking device according to claim 1, characterized in that: The impact chamber is used to achieve impact mixing of materials, and an impact angle and an impact surface are arranged in the impact chamber.

4. A waste plastic catalytic cracking device according to claim 2, characterized in that: The static fluid changing structure comprises: multiple layers of staggered baffles.

5. A waste plastic catalytic cracking device according to claim 1, characterized in that: The primary separation tank (6) and the secondary separation tank (7) are both provided with a filtering layer.

6. A waste plastic catalytic cracking device according to claim 1, characterized in that: The bottom of the secondary separation tank (7) is provided with an ash discharge pipe.

7. A method for using a waste plastic catalytic cracking device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: feeding the waste plastic and the catalyst into a three-stream impinging stream feeder (1) at a total feed rate of 500 g / min at a temperature of 15-25° C. to form a mixed material; S2: Entering the descending bed reactor (2), the mixed material reacts for 25-35 minutes under the action of the static fluid structure, and the reaction temperature is 350-450°C; S3: Entering the circulating fluidized bed (3) for treatment, the combustible gas is sent to the backfire device (4) for combustion; S4: transporting upward through a multi-flow riser (5) to a primary separation tank (6) for preliminary separation; S5: The recyclable part is sent back to the three-stream impinging flow feeder (1) for reuse, and the non-recyclable part is introduced into the secondary separation tank (7) for treatment and discharged through the ash discharge pipe.

8. The method for using the waste plastic catalytic cracking device according to claim 7, characterized in that: In the S1, the mass ratio of waste plastic to catalyst is in the range of 1-3:1-3, and the mixing time is in the range of 5-10 min.

9. The method for using the waste plastic catalytic cracking device according to claim 7, characterized in that: In S3, the temperature of the circulating fluidized bed (3) is in the range of 250-350°C, the treatment time is in the range of 30-40 minutes, the temperature of the backfire device (4) is in the range of 800-1000°C, and the combustion time is in the range of 5-15 minutes.

10. The method for using the waste plastic catalytic cracking device according to claim 7, characterized in that: In S5, the treatment temperature of the primary separation tank (6) and the secondary separation tank (7) is 25-30°C.

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