Production line system capable of realizing continuous degradation of polyethylene
By designing a continuous production line system, continuous flow degradation of polyethylene was achieved, solving the problem of catalyst and product separation, improving production efficiency and product quality, and making it suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-09
- Publication Date
- 2026-03-27
AI Technical Summary
Existing technologies make it difficult to achieve large-scale continuous degradation of polyethylene, and the catalyst is difficult to separate from the degradation products, resulting in low production efficiency, unstable product quality, and difficulty in meeting industrial needs.
A continuous production line system including a feeding vessel, a buffer vessel, a melt pump, and a fixed-bed reactor was designed. The continuous flow degradation of polyethylene is achieved through fluid pipeline connections. Inert gas protection and constant temperature heating are adopted. The catalyst is recycled in the fixed-bed reactor to avoid the problem of catalyst separation from the product.
It enables continuous degradation of polyethylene, improves catalyst lifespan and the reuse value of degradation products, significantly enhances production efficiency and product quality, and is suitable for industrial applications.
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Figure CN224040888U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a production line system that can realize the continuous degradation of polyethylene, belonging to the technical field of organic chemistry. BACKGROUND
[0002] Polyethylene plastic is the most common and widely used synthetic polymer plastic in modern life, and it plays an important role in agriculture, packaging, construction, automobiles and even aerospace. However, because the molecular chain of polyethylene is composed of extremely stable saturated C-C bonds and C-H bonds, it has relatively inert chemical properties, so it is difficult to degrade without special treatment. As a result, most polyethylene plastic waste is currently buried, discarded as "white pollution", and a small number is incinerated or physically recycled, while the proportion of chemical recycling is very small.
[0003] In addition, traditional chemical recycling methods usually involve thermal cracking, hydrocracking or oxidative cracking of polyethylene plastic at high temperatures. These methods require very high energy consumption or the use of environmentally unfriendly chemicals, and the resulting product components are complex and have low utilization value. Therefore, finding a polyethylene degradation technology that is mild in conditions, has good selectivity, produces fewer by-products, has high reaction conversion rate, produces products with high reuse value, is environmentally friendly, and is suitable for industrialization, has always been a technical problem that needs to be solved in the field.
[0004] A research group led by Huang Zheng of the Shanghai Institute of Organic Chemistry of the Chinese Academy of Sciences has disclosed in Chinese Patent No. 201410415203.7 a method for degrading polyethylene into liquid fuel or / and polyethylene wax by multiple cross-metathesis reactions between C2-C10 alkanes and polyethylene in the presence of an alkane dehydrogenation catalyst and an olefin metathesis catalyst. Although this patent technology can achieve the mild and controllable degradation and recycling of different types of polyethylene such as HDPE, LLDPE and LDPE, and has mild reaction conditions, it can overcome the shortcomings of traditional polyethylene degradation methods such as high reaction temperature, complex products and low product application value. However, the research group found in subsequent large-scale experiments that the reaction system has a very high viscosity, and if traditional tank reactors are used, there are problems such as non-uniform reaction, low degradation efficiency, and difficulty in separating the catalyst from the material, making it difficult to achieve large-scale application. In addition, intermittent reaction operations usually require multiple additions and removals of reactants, catalysts and solvents, which not only increases the complexity of the operation and reduces the production efficiency, but also may cause fluctuations in reaction conditions, thereby affecting the quality and yield of the product, making it difficult to meet the needs of large-scale industrial production. UTILITY MODEL CONTENTS
[0005] The utility model discloses a production line system that can realize the continuous degradation of polyethylene aims at the above-mentioned problems existing in prior art.
[0006] To realize the above-mentioned purpose, the utility model adopts the technical scheme as follows:
[0007] A production line system that can realize the continuous degradation of polyethylene, comprising a feed tank, a buffer tank, a melt pump, a fixed bed type reaction device with constant temperature and heating function and a one-in-two-out three-way ball valve V, wherein the discharge port of the feed tank is connected to the feed inlet of the buffer tank through a fluid pipeline, the discharge port of the buffer tank is connected to the feed inlet of the melt pump through a fluid pipeline, the discharge port of the melt pump is connected to the inlet of the one-in-two-out three-way ball valve V through a fluid pipeline, one outlet of the one-in-two-out three-way ball valve V is connected to the feed inlet of the fixed bed type reaction device through a fluid pipeline, and the other outlet is empty, and the discharge port of the fixed bed type reaction device is connected to a product receiver.
[0008] In one embodiment, the fixed bed type reaction device is a single one.
[0009] In another embodiment, the fixed bed type reaction device is a plurality of devices, and the plurality of devices are connected in series, one outlet of the one-in-two-out three-way ball valve V is connected to the feed inlet of the first fixed bed type reaction device, and the product receiver is connected to the discharge port of the last fixed bed type reaction device.
[0010] In a preferred embodiment, the production line system further comprises a vacuum oil pump, and each of the feed tank and the buffer tank is provided with an exhaust port connected to the vacuum oil pump through a silica gel tube.
[0011] In a preferred embodiment, the production line system further comprises an inert gas cylinder, and each of the feed tank and the buffer tank is provided with an air inlet connected to the pressure reducing valve of the inert gas cylinder through a silica gel tube.
[0012] In a preferred embodiment, each of the feed tank and the buffer tank is provided with an electric heating jacket made of aluminum silicate fiber.
[0013] In a preferred embodiment, each of the feed tank and the buffer tank is provided with a magnetic coupling mechanical stirrer.
[0014] In a preferred embodiment, each of the feed tank and the buffer tank is provided with a digital display controller for real-time monitoring of the temperature, pressure and mechanical stirring speed inside the tank.
[0015] One embodiment, the fixed bed reactor with constant temperature and heating function is composed of a fixed bed reactor and an oven with constant temperature and heating function, the fixed bed reactor is fixed in the oven by a clamp, and the fluid pipeline through holes for connecting the feed inlet or discharge outlet of the fixed bed reactor are arranged on both side walls of the oven.
[0016] A preferred embodiment, the fixed bed reactor is an axial adiabatic fixed bed reactor.
[0017] A preferred embodiment, the discharge outlet of the fixed bed reactor is arranged at the top end of the fixed bed reactor, and the feed inlet of the fixed bed reactor is arranged at the bottom end of the fixed bed reactor.
[0018] A preferred embodiment, the fluid pipeline is a stainless steel pipe.
[0019] A preferred embodiment, the fluid pipeline is wound with a heating belt.
[0020] A further preferred embodiment, the heating belt is a glass fiber electric heating belt.
[0021] Compared with the prior art, the beneficial technical effects of the present application are that:
[0022] The production line system can realize continuous flow degradation reaction of polyethylene, not only realizing continuous degradation production of polyethylene, but also effectively avoiding the bottleneck of difficult separation of catalyst and degradation products, so that the polyethylene degradation products have high reuse value, and the service life of the catalyst is significantly improved and efficient recycling of the catalyst is realized. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 is a structure schematic view of a production line system capable of realizing continuous degradation of polyethylene provided in embodiment 1;
[0024] Figure 2 is a structure schematic view of a feed kettle in embodiment 1;
[0025] Figure 3 is a structure schematic view of a buffer kettle in embodiment 1;
[0026] Figure 4 is a structure schematic view of a fixed bed reactor with constant temperature and heating function in embodiment 1;
[0027] Figure 5 is a structure schematic view of another production line system capable of realizing continuous degradation of polyethylene provided in embodiment 2. DETAILED DESCRIPTION
[0028] The technical scheme of the utility model is further described in detail below in combination with the drawings and examples. In addition, it should be noted that the terms used in the utility model are only for the purpose of describing specific examples, and are not intended to limit the utility model. Unless otherwise defined, the technical terms or scientific terms used in the utility model should be understood as the general meaning understood by those skilled in the art. The experimental methods not specified in the following examples are selected according to the conventional methods and conditions, or according to the product instructions.
[0029] Example 1
[0030] Please see Figure 1 As shown in the drawings, the production line system capable of realizing continuous degradation of polyethylene provided in the embodiment comprises a feeding kettle 1, a buffer kettle 2, a melt pump 3, a fixed bed type reaction device 4 with constant temperature and heating functions and a one-in-two-out three-way ball valve V. The discharge port of the feeding kettle 1 is connected with the feeding port of the buffer kettle 2 through a fluid pipeline 6-1, the discharge port of the buffer kettle 2 is connected with the feeding port of the melt pump 3 through a fluid pipeline 6-2, the discharge port of the melt pump 3 is connected with the inlet of the one-in-two-out three-way ball valve V through a fluid pipeline 6-3, one outlet of the one-in-two-out three-way ball valve V is connected with the feeding port of the fixed bed type reaction device 4 through a fluid pipeline 6-4, and the other outlet is emptied, and the discharge port of the fixed bed type reaction device 4 is connected with a product receiver 5. In the embodiment, the fixed bed type reaction device 4 with constant temperature and heating functions is single.
[0031] Specifically, please see Figure 2As shown, the feed kettle 1 described in the embodiment includes a kettle body 1-1 and a kettle cover 1-2 made of stainless steel, an electric heating jacket 1-3 made of aluminum silicate fiber is arranged outside the kettle body 1-1, and an anchor stirring paddle 1-4 is arranged in the kettle body 1-1; a magnetic coupling mechanical stirrer 1-5 is further arranged on the kettle body 1-1, the magnetic coupling mechanical stirrer 1-5 is a commercially available known product, including a stirring head 1-51 and a driving motor 1-52; a feeding port 1-21 is arranged on the kettle cover 1-2, the upper end of the feeding port 1-21 is sealed by a stud 1-211 and a rubber gasket 1-212, and the setting position of the feeding port 1-21 is not specially limited, as long as it does not interfere with other designs on the kettle cover 1-2; a discharge port 1-22 is further arranged on the kettle cover 1-2, the discharge port 1-22 is provided with a stainless steel pipe 1-221, the lower end of the stainless steel pipe 1-221 extends to the bottom of the kettle body 1-1, and the upper end of the stainless steel pipe 1-221 is provided with a two-way ball valve 1-222, the upper end of the two-way ball valve 1-222 is connected with a fluid pipeline 6-1; an air inlet 1-23 is further arranged on the kettle cover 1-2, the air inlet 1-23 is provided with a stainless steel pipe 1-231, the lower end of the stainless steel pipe 1-231 extends to about 50 mm deep inside the kettle body 1-1, and the upper end of the stainless steel pipe 1-231 is provided with a two-way needle valve 1-232; an exhaust port 1-24 is further arranged on the kettle cover 1-2, the exhaust port 1-24 is provided with a stainless steel pipe 1-241, the lower end of the stainless steel pipe 1-241 is parallel to the top end of the kettle body 1-1, and the upper end of the stainless steel pipe 1-241 is provided with a two-way needle valve 1-242; a temperature probe insertion pipe 1-25 is further arranged on the kettle cover 1-2, the lower end of the temperature probe insertion pipe 1-25 extends to the middle section inside the kettle body 1-1; a pressure gauge 1-26 is further arranged on the kettle cover 1-2; in addition, the feed kettle 1 is further provided with a digital display controller (not shown in the figure, the position of the digital display controller can be designed according to the prior art) for real-time monitoring of the temperature, pressure and mechanical stirring speed inside the kettle body 1-1, the kettle body 1-1 can withstand a pressure of 4 MPa, and the working temperature can reach 200℃.
[0032] See Figure 3As shown, the buffer kettle 2 also includes a kettle body 2-1 and a kettle cover 2-2 made of stainless steel, an electric heating jacket 2-3 made of aluminum silicate fiber is arranged outside the kettle body 2-1, an anchor stirring paddle 2-4 is arranged inside the kettle body 2-1, a discharge port 2-5 is arranged at the bottom of the kettle body 2-1, the discharge port 2-5 is provided with a stainless steel pipe 2-51, the lower end of the stainless steel pipe 2-51 is provided with a ball valve 2-52 for controlling the discharge, the stainless steel pipe 2-51 at the lower end of the ball valve 2-52 is connected with the fluid pipeline 6-2 through a reducing joint; the side of the kettle body 2-1 is provided with a pressure-resistant glass observation window 2-6, the pressure-resistant glass observation window 2-6 is provided with a liquid level scale; a magnetic coupling mechanical stirrer 2-7 is further arranged on the kettle body 2-1, the magnetic coupling mechanical stirrer 2-7 is a commercially available known product, which includes a stirring head 2-71 and a driving motor 2-72; the kettle cover 2-2 is provided with a feeding port 2-21, the feeding port 2-21 is provided with a stainless steel pipe 2-211, the lower end of the stainless steel pipe 2-211 extends to about 50 mm deep inside the kettle body 2-1, the upper end of the stainless steel pipe 2-211 is provided with a two-way ball valve 2-212, the two-way ball valve 2-212 is connected with the fluid pipeline 6-1; the kettle cover 2-2 is further provided with an air inlet 2-22, the air inlet 2-22 is provided with a stainless steel pipe 2-221, the lower end of the stainless steel pipe 2-221 extends to about 50 mm deep inside the kettle body 2-1, the upper end of the stainless steel pipe 2-221 is provided with a two-way needle valve 2-222; the kettle cover 2-2 is further provided with an exhaust port 2-23, the exhaust port 2-23 is provided with a stainless steel pipe 2-231, the lower end of the stainless steel pipe 2-231 is parallel to the top end of the kettle body 2-1, the upper end of the stainless steel pipe 2-231 is provided with a two-way needle valve 2-232; the kettle cover 2-2 is further provided with a temperature probe insertion tube 2-24, the lower end of which extends to the middle section inside the kettle body 2-1; the kettle cover 2-2 is further provided with a pressure gauge 2-25; in addition, the buffer kettle 2 is further provided with a digital display controller (not shown in the figure, the position of the digital display controller can be designed according to the prior art) for real-time monitoring of the temperature, pressure and mechanical stirring speed inside the kettle body 2-1, the kettle body 2-1 can withstand a pressure of 1 MPa, and the working temperature can reach 200℃.
[0033] As a preferred solution, please see Figure 1As shown, the production line system described in the embodiment further comprises a vacuum oil pump 7 and an inert gas cylinder 8, the gas inlet 1-23 of the supply tank 1 is connected to the pressure reducing valve of the inert gas cylinder 8 via a two-way needle valve 1-232 and a silica gel tube 9-1, and the gas outlet 1-24 of the supply tank 1 is connected to the vacuum oil pump 7 via a two-way needle valve 1-242 and a silica gel tube 9-2; the gas inlet 2-22 of the buffer tank 2 is connected to the pressure reducing valve of the inert gas cylinder 8 via a two-way needle valve 2-222 and a silica gel tube 9-3, and the gas outlet 2-23 of the buffer tank 2 is connected to the vacuum oil pump 7 via a two-way needle valve 2-232 and a silica gel tube 9-4, which is beneficial to realize inert atmosphere operation in the supply tank 1 and the buffer tank 2.
[0034] In addition, please refer to Figure 4 As shown, the fixed bed reaction device 4 with constant temperature and heating function described in the embodiment is composed of a fixed bed reactor 4-1 and an oven 4-2 with constant temperature and heating function, the fixed bed reactor 4-1 is fixed in the oven 4-2 by a clamp 4-3 (in the figure, it is composed of a fixed rod 4-31 and a plurality of fixed clamps 4-32, the fixed rod 4-31 is fixedly connected to the inner wall of the rear side of the oven 4-2, a plurality of fixed clamps 4-31 are fixedly arranged on the fixed rod 4-31 at intervals, and the fixed clamps 4-32 can clamp the pipe body of the fixed bed reactor 4-1), and the two side walls of the oven 4-2 are both provided with perforations 4-21 for connecting the fluid pipelines 6-4 and 6-5 to the feed inlet 4-11 and the discharge outlet 4-12 of the fixed bed reactor. The fixed bed reactor 4-1 selects an existing axial adiabatic fixed bed reactor, the discharge outlet 4-12 of the fixed bed reactor is arranged at the top end of the fixed bed reactor 4-1, and the feed inlet 4-11 of the fixed bed reactor is arranged at the bottom end of the fixed bed reactor 4-1. The oven 4-2 is transformed from an existing oven, and the transformation is only to add the clamp 4-3 to the rear side inner wall 4-22 of the oven and add the perforations 4-21 to the left side wall 4-23 and the right side wall 4-24 of the oven.
[0035] In addition, the fluid pipelines 6-1 to 6-5 described in the embodiment are all stainless steel pipes, heating tapes are wound on the fluid pipelines 6-1 to 6-5 (the part of the fluid pipelines 6-4 and 6-5 located in the oven 4-2 does not need to be wound), the heating tapes select commercially available glass fiber electric heating tapes, the heating tapes are provided with a controller and a temperature measuring probe, and the maximum use temperature can reach 200°C. The melt pump 3 described in the embodiment preferably has a flow rate range of 0.1 mL / min to 100 mL / min, can withstand a temperature of 200°C, and can withstand a pressure of 20 MPa.
[0036] The production line system described in the embodiment can be used to continuously degrade polyethylene into polyethylene wax main product and liquid fuel byproduct under the condition that alkane dehydrogenation catalyst and olefin metathesis catalyst coexist, using alkane as solvent and common reaction substrate.
[0037] The operation of continuously degrading polyethylene using the production line system described in the embodiment includes the following sequential steps:
[0038] A) Add the first batch of proportioned amount of waste polyethylene raw material and alkane as solvent and common reaction substrate into the feed tank 1 through the feeding port 1-21 on the feed tank 1, then close the feeding port 1-21 on the tank cover 1-2, use the vacuum oil pump 7 and the inert gas cylinder 8 (argon cylinder is used in this embodiment) in combination to replace the inside of the feed tank 1 with argon for 3-5 times, then fill argon into the feed tank 1 until the pressure inside the tank reaches 0.1 MPa, so that the feed tank 1 always maintains a certain positive argon pressure for standby; use the same operation to replace the inside of the buffer tank 2 with argon for 3-5 times, and fill argon into the buffer tank 2 until the pressure inside the tank reaches 0.1 MPa, so that the buffer tank 2 always maintains a certain positive argon pressure for standby; then turn on the heating power through the two independent digital controllers on the two tanks to heat the respective tanks to the preset temperature (190°C in this embodiment), and open the respective stirrers at the preset stirring speed (120 r / min in this embodiment);
[0039] B) The proportioned amount of alkane dehydrogenation catalyst and olefin metathesis catalyst are pre-mixed to obtain a two-component alkane metathesis heterogeneous catalyst, which is then filled into the fixed bed reactor 4-1 in the fixed bed reactor of the fixed bed reactor 4 with constant temperature and heating function. The specific operation is as follows: in the argon-filled glove box, 500 mL round bottom flask is sequentially added with [Ir] catalyst (1.8 g in this embodiment), toluene (200 mL), and shaken until the solution is fully dissolved and the solution is deep red, then spherical granular γ-Al2O3 with particle size of 0.5-1 mm (90 g) is added, and the upper clear solution is shaken until it becomes colorless, so that the [Ir] catalyst is fully loaded on the γ-Al2O3, then the round bottom flask is sealed and taken out of the glove box, and a vacuum pump is connected to dry all the solvents in it, to obtain a pink alkane dehydrogenation heterogeneous catalyst, then the dried alkane dehydrogenation heterogeneous catalyst is re-moved into the argon-filled glove box, and the olefin metathesis catalyst 5% Re2O7 / γ-Al2O3 (90 g) pre-activated in the tube furnace is added, and shaken until the two are fully mixed and uniform, to obtain a two-component alkane metathesis heterogeneous catalyst; then the two-component alkane metathesis heterogeneous catalyst is filled into the fixed bed reactor 4-1, and the inlet and outlet ports of the fixed bed reactor 4-1 are sealed with plugs, then the fixed bed reactor 4-1 is removed from the argon-filled glove box and placed in the oven 4-2, the fixed bed reactor 4-1 is fixed by the clamp 4-3 in the oven 4-2, then the plugs at both ends of the fixed bed reactor 4-1 are unscrewed and quickly connected with the fluid pipeline penetrating into the oven 4-2;
[0040] C) The outlet of the three-way ball valve V is switched to communicate with the inlet of the fixed bed reactor 4, and the voltage of the melt pump 3 is set to 0.5 V (the conversion flow rate is about 60 mL / min), so that 200 mL of material is input into the fixed bed reactor 4-1 in the fixed bed reactor 4, then the heating power of the oven 4-2 is turned on and heated to the preset 190°C, and the heating power of the melt pump 3 and the glass fiber heating belt wrapped on the fluid pipeline are turned on and heated to the preset 190°C;
[0041] D) The argon gas is filled into the feed tank 1 until the pressure in the feed tank 1 reaches 0.4 MPa, then the two-way ball valve 1-222 on the outlet 1-22 of the feed tank 1 and the two-way ball valve 2-212 on the inlet 2-21 of the buffer tank 2 are opened, and the remaining material in the feed tank 1 is completely transported into the buffer tank 2 by the argon pressure, after the transportation is completed, the pressure in the buffer tank 2 is maintained (about 0.2 MPa), and the two-way ball valve 1-222 on the outlet 1-22 of the feed tank 1 and the two-way ball valve 2-212 on the inlet 2-21 of the buffer tank 2 are closed;
[0042] E) Set the voltage of the melt pump 3 to 0.1 V (equivalent flow rate of about 12 mL / min) to slowly transfer the material in the buffer tank 2 to the fixed bed reactor 4-1 for the olefin metathesis reaction, and the product obtained by the reaction is directly collected by the product receiver 5; at the same time, the second batch of the waste polyethylene raw material and the alkane as the solvent and the co-reactant are added into the feed tank 1 through the feeding port 1-21 on the feed tank 1, then the feeding port 1-21 on the tank cover 1-2 is closed, the inside of the feed tank 1 is replaced with argon for 3-5 times by using the vacuum pump 7 and the inert gas cylinder 8 (argon cylinder is used in this embodiment), and then the feed tank 1 is filled with argon to a pressure of 0.1 MPa, so that the feed tank 1 is always kept at a certain argon positive pressure for standby;
[0043] F) When it is observed through the pressure-resistant glass observation window 2-6 that the first batch of material in the buffer tank 2 is about to be transferred, the feed tank 1 is filled with argon to a pressure of 0.4 MPa, and then the two-way ball valve 1-222 on the discharge port 1-22 of the feed tank 1 and the two-way ball valve 2-212 on the feeding port 2-21 of the buffer tank 2 are opened, so that the remaining material in the feed tank 1 is transferred to the buffer tank 2 by argon pressure, after the transfer is completed, the pressure in the buffer tank 2 (about 0.2 MPa) is kept, and the two-way ball valve 1-222 on the discharge port 1-22 of the feed tank 1 and the two-way ball valve 2-212 on the feeding port 2-21 of the buffer tank 2 are closed, so as to realize the continuous degradation reaction of the second batch of material, and in this way, the continuous degradation reaction of multiple batches of material can be realized;
[0044] G) The degradation product collected in step F) is diluted and dispersed with n-pentane, filtered through a sand core funnel, and the filter cake is washed with n-pentane for multiple times (for example, 3-5 times), and then vacuum dried at 75°C until the weight is constant, to obtain the polyethylene wax main product, and the oil obtained by removing the n-pentane solvent from the filtrate at room temperature is the liquid fuel byproduct.
[0045] It should be noted that the selection of the alkane, the alkane dehydrogenation catalyst, the olefin metathesis catalyst and the reaction temperature in this embodiment is disclosed in the Chinese patent with the patent number 201410415203.7. The waste polyethylene raw material is a powder obtained by cleaning, drying and crushing the waste polyethylene products in the form of polyethylene plastic boxes, polyethylene preservative films, polyethylene shopping bags, etc.
[0046] Example 2
[0047] Please refer to Figure 5As shown, the production line system capable of realizing continuous degradation of polyethylene provided by the embodiment only differs from the production line system described in the embodiment 1 in that the fixed bed type reaction device 4 is two, and the two fixed bed type reaction devices are connected in series, one outlet of the three-way ball valve V is connected with the feed inlet of the first fixed bed type reaction device 4a, and the product receiver 5 is connected with the discharge outlet of the last fixed bed type reaction device 4b; the rest is the same as described in the embodiment 1.
[0048] The embodiment can increase the contact reaction time of the material and the catalyst by adding the fixed bed type reaction device 4, so as to improve the degradation efficiency of the polyethylene.
[0049] Finally, it is necessary to point out here that the above description is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A production line system enabling continuous degradation of polyethylene, characterized by: The production line system comprises a feed tank, a buffer tank, a melt pump, a fixed bed type reaction device with constant temperature and heating function, and a one-in-two-out three-way ball valve V.
2. The production line system enabling continuous degradation of polyethylene according to claim 1, characterized in that: The fixed bed type reaction device is single.
3. The production line system enabling continuous degradation of polyethylene according to claim 1, characterized in that: The fixed bed type reaction device is multiple, and the multiple fixed bed type reaction devices are connected in series.
4. The production line system enabling continuous degradation of polyethylene according to claim 1, characterized in that: The production line system further comprises a vacuum oil pump, and the feed tank and the buffer tank are both provided with exhaust ports connected with the vacuum oil pump through silica gel pipes.
5. The production line system enabling continuous degradation of polyethylene according to claim 1 or 4, characterized in that: The production line system further comprises an inert gas cylinder, and the feed tank and the buffer tank are both provided with gas inlets connected with a pressure reducing valve of the inert gas cylinder through silica gel pipes.
6. The production line system enabling continuous degradation of polyethylene according to claim 1, characterized in that: The feed tank and the buffer tank are both provided with an electric heating jacket of aluminum silicate fiber and a magnetic coupling mechanical stirrer.
7. The production line system enabling continuous degradation of polyethylene according to claim 1 or 6, characterized in that: The feed tank and the buffer tank are both provided with a digital display controller for monitoring the temperature, pressure and mechanical stirring speed in the tank in real time.
8. The production line system enabling continuous degradation of polyethylene according to claim 1, characterized in that: The fixed bed type reaction device with constant temperature and heating function is composed of a fixed bed reactor and an oven with constant temperature and heating function.
9. The production line system enabling continuous degradation of polyethylene according to claim 8, characterized in that: The fixed bed reactor is fixed in the oven through a clamp, and both sides of the oven are provided with perforations for connecting the fluid pipes with the inlets or outlets of the fixed bed reactor.
10. The production line system enabling continuous degradation of polyethylene according to claim 1, characterized in that: The fixed bed reactor is an axial adiabatic fixed bed reactor, and the outlet of the fixed bed reactor is arranged at the top end of the fixed bed reactor. The fluid pipe is a stainless steel pipe, and a heating belt is wound on the fluid pipe.
Citation Information
Patent Citations
Polyethylene degradation method, product and application thereof
CN105348557A