A method for recycling plastic waste

Abstract

The present invention belongs to the technical field of plastic modification and processing, and relates to the field of recycling of marine plastic waste. A method for recycling plastic waste is disclosed, which includes the following steps: sorting the plastic waste to be recycled to obtain heavy plastics and light plastics; subjecting the heavy plastics to catalytic amine cracking to obtain heavy plastic-derived additives; melting, mixing and kneading virgin asphalt, recycled asphalt, asphalt rejuvenator and heavy plastic-derived additives in a preset ratio to obtain heavy plastic-derived agent-modified recycled asphalt; catalytically pyrolyzing the light plastics to prepare carbon nanotubes and hydrogen-rich gas. The present invention separately prepares modified asphalt, as well as carbon nanotubes and hydrogen-rich gas based on the heavy plastics and light plastics obtained by sorting; it can solve the segregation problem of plastic-modified asphalt, and at the same time can achieve the efficient recycling and high-value utilization of plastic waste.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic modification and processing, relates to the field of recycling of marine plastic waste, and particularly relates to a method for recycling plastic waste. Background Art

[0002] As one of the products of petrochemical industry, plastics are widely used in many fields due to their light weight, easy to carry, low production cost and other characteristics. At present, the global annual production of plastics exceeds 300 million tons, and a large number of plastic products are discarded at will; among them, more than 8 million tons of plastic waste enter the ocean every year, accounting for 80% of all marine waste. The physical and chemical structures of plastics are stable, and they will not be decomposed in the natural environment for dozens or even hundreds of years, which will pollute the ocean for a long time, not only threatening the survival of marine organisms, but also having a serious impact on food safety, human health and coastal tourism, and it is one of the top ten environmental problems in the world today.

[0003] In addition, with the rapid development of cities, asphalt is widely used in highway construction; under the natural actions of sunlight, rain, oxidation, etc., asphalt will undergo a series of volatilization, oxidation, and polymerization reactions, resulting in essential changes in the internal structure and properties of asphalt. This similar asphalt aging process makes the road surface dry and brittle, and then cracks and loosens, leading to deterioration of road performance. Explanatorily, the aging of asphalt is mainly manifested by the change of its components, a large reduction in oil content, an increase in asphaltene, and a change in the colloidal structure, which increases the viscosity of asphalt and decreases the rheological index, resulting in a decline in asphalt performance.

[0004] Based on the above situation, using waste plastic waste to modify asphalt is an environmentally friendly modified asphalt method for resource recycling. The current treatment methods mostly mix the waste plastics into asphalt after physical treatment to improve the performance of asphalt. However, in the above existing methods, when the plastic waste is mixed with asphalt in a high-temperature molten state, the plastic will decompose, and there are many unstable factors in the components, which will have an unstable impact on the asphalt modification process and will also affect the storage stability of the modified asphalt at room temperature, and it is difficult to effectively solve the segregation problem of plastic-modified asphalt. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for recycling plastic waste to solve one or more of the above technical problems. In the technical solution provided by the present invention, first, the plastic waste is sorted, and based on the heavy plastics and light plastics obtained by sorting, modified asphalt, carbon nanotubes and hydrogen-rich gas are respectively prepared; the segregation problem of plastic-modified asphalt can be solved, and at the same time, the efficient recycling and high-value utilization of plastic waste can be realized.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for recycling plastic waste provided by the first aspect of the present invention includes the following steps:

[0008] Sort the plastic waste to be recycled to obtain heavy plastics and light plastics;

[0009] Subject the heavy plastics to catalytic aminolysis to obtain heavy plastic-derived additives; melt, mix and knead virgin asphalt, recycled asphalt, asphalt rejuvenator and the heavy plastic-derived additives in a preset ratio to prepare heavy plastic-derived agent modified recycled asphalt;

[0010] Subject the light plastics to catalytic pyrolysis to prepare carbon nanotubes and hydrogen-rich gas.

[0011] A further improvement of the method of the present invention lies in that in the step of sorting the plastic waste to be recycled to obtain heavy plastics and light plastics,

[0012] The sorting method used is wind density sorting method or buoyancy density sorting method.

[0013] A further improvement of the method of the present invention lies in that in the step of subjecting the heavy plastics to catalytic aminolysis to obtain heavy plastic-derived additives,

[0014] The aminolysis agent is triethylenediamine or ethylenediamine ；

[0015] The catalyst is sodium acetate or sodium carbonate;

[0016] The reaction temperature of catalytic aminolysis is 80°C to 110°C.

[0017] A further improvement of the method of the present invention lies in that in the step of melting, mixing and kneading virgin asphalt, recycled asphalt, asphalt rejuvenator and the heavy plastic-derived additives in a preset ratio to prepare heavy plastic-derived agent modified recycled asphalt,

[0018] The preset ratio is, by mass, 40 to 80 parts of virgin asphalt, 60 to 120 parts of recycled asphalt, 10 to 20 parts of asphalt rejuvenator, and 1 wt% to 4 wt% of heavy plastic-derived additives.

[0019] A further improvement of the method of the present invention lies in that in the step of melting, mixing and kneading virgin asphalt, recycled asphalt, asphalt rejuvenator and the heavy plastic-derived additives in a preset ratio to prepare heavy plastic-derived agent modified recycled asphalt,

[0020] The molten kneading and mixing includes: stirring recycled asphalt and brand-new asphalt at 210°C to 240°C, heating and blending the asphalt until it becomes molten and fully mixed; then, adding an asphalt rejuvenator and continuing to stir to adjust the viscosity of the blend to 1.8 Pa·s to 2.3 Pa·s, obtaining a recycled asphalt binder; gradually cooling the recycled asphalt binder while continuously stirring, and adding heavy marine plastic-derived additive particles when the temperature drops to 150°C to 180°C, and stirring to obtain a heavy marine plastic-derived additive modified recycled asphalt.

[0021] A further improvement of the method of the present invention lies in that in the step of catalytic pyrolysis of the light plastic to obtain carbon nanotubes and hydrogen-rich gas,

[0022] The catalytic pyrolysis of the light plastic is carried out by a two-stage method.

[0023] A further improvement of the method of the present invention lies in that the step of catalytic pyrolysis of the light plastic by a two-stage method specifically includes:

[0024] Dissolve Fe(NO3)3·9H2O in an ethanol solvent, then add γ-Al2O3 to form a suspension, dry, calcine, and grind to obtain an Fe / γ-Al2O3 cracking catalyst; wherein, by mass, 0.5 to 1.0 parts of Fe(NO3)3·9H2O, 2 to 4 parts of ethanol solvent, and 0.5 to 1.0 parts of γ-Al2O3;

[0025] Under a N2 protective atmosphere, the light plastic particles and the Fe / γ-Al2O3 cracking catalyst are catalytically pyrolyzed at a temperature of 500°C to 600°C; wherein, by mass, the ratio of the light plastic to the Fe / γ-Al2O3 cracking catalyst is (4 to 20):1;

[0026] Under a N2 protective atmosphere, the pyrolysis gas obtained by catalytic pyrolysis is catalytically reformed using a Ni-Al2O3 metal catalyst at a temperature of 800°C to 1000°C to obtain carbon nanotubes and hydrogen-rich gas.

[0027] A method for recycling marine plastic waste provided in the second aspect of the present invention is based on the method for recycling plastic waste described in the first aspect of the present invention;

[0028] Wherein, the plastic waste to be recycled is marine plastic waste.

[0029] A further improvement of the present invention lies in that the step of sorting the plastic waste to be recycled to obtain heavy plastic and light plastic includes:

[0030] Sort out the plastic with a density greater than 1.3 g·cm -3 as heavy plastic, and the plastic with a density less than 1.15 g·cm -3; the plastic is lightweight plastic.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] In the technical solution provided by the present invention, first, plastic waste is sorted, and based on the heavy plastic and lightweight plastic obtained by sorting, modified asphalt, carbon nanotubes, and hydrogen-rich gas are respectively prepared; the segregation problem of plastic modified asphalt can be solved, and at the same time, the efficient recycling and high-value utilization of plastic waste can be realized. Specifically, in the present invention, part of the raw material of asphalt is replaced with aged recycled asphalt, supplemented with derivative additives obtained by amine cracking of heavy plastic, and recycled modified asphalt is prepared. By consuming a large amount of plastic waste and reducing the consumption of new asphalt, the recycling of plastic waste is completed, achieving a win-win situation of resource reuse and environmental protection; further emphasized is that the recycled modified asphalt prepared by using heavy plastic derivative additives has an increased softening point, a decreased penetration, and improved technical properties such as high-temperature performance, extending its service life.

[0033] The present invention uses lightweight plastic as a raw material, and carbon nanotubes and hydrogen-rich gas are prepared in a two-stage fixed bed by pyrolysis and catalytic reaction. The application of this method can not only solve the problem of a large amount of plastic waste, but also provide a cheap carbon source for the preparation of carbon nanotubes with unrestricted source and transportation. At the same time, this method has the advantages of high carbon conversion rate, high product quality, flexible operation, and low operating cost.

[0034] The present invention also provides a new method for the efficient recycling of marine plastic waste. Based on the above method, through the classified recycling of marine waste, the preparation of recycled modified asphalt from heavy marine plastic derivative additives, carbon nanotubes using lightweight marine plastic as a carbon source, and the by-product hydrogen-rich gas is completed. This method also broadens the treatment route of marine plastic waste, can efficiently turn marine plastic waste into treasures, and improves the added value of marine plastic waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the description of the embodiments or the prior art; obviously, the following drawings are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 is a schematic flow chart of a method for recycling plastic waste provided by an embodiment of the present invention;

[0037] Figure 2 is a schematic flow chart of a method for the efficient recycling of marine plastic waste provided by an embodiment of the present invention;

[0038] Figure 3 It is a schematic diagram of the preparation process of the heavy marine plastic-derived additive and its recycled modified asphalt in the embodiments of the present invention;

[0039] Figure 4 It is a schematic diagram of the process for preparing carbon nanotubes and their associated hydrogen-rich gas products using light marine plastics as a carbon source in the embodiments of the present invention. Specific embodiments

[0040] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the protection scope of the present invention.

[0041] The following illustrates the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0042] It should be noted that the process equipment or devices not specifically noted in the following embodiments all adopt conventional equipment or devices in the art.

[0043] In addition, it should be understood that one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combined steps or the insertion of other method steps between these clearly mentioned steps, unless otherwise stated; it should also be understood that the combined connection relationship between one or more devices / devices mentioned in the present invention does not exclude the existence of other devices / devices before and after the combined devices / devices or the insertion of other devices / devices between these two clearly mentioned devices / devices, unless otherwise stated. Moreover, unless otherwise stated, the numbers of the method steps are only convenient tools for identifying the method steps, rather than limiting the arrangement order of the method steps or the scope in which the present invention can be implemented. The change or adjustment of their relative relationship, without substantial change in the technical content, should also be regarded as the scope in which the present invention can be implemented.

[0044] Please refer to Figure 1 , a method for recycling plastic waste disclosed in the embodiments of the present invention, includes the following steps:

[0045] Step 1, sorting the plastic waste to be recycled to obtain heavy plastics and light plastics;

[0046] Step 2: Catalytic amine cracking is performed on the heavy plastics to obtain heavy plastic-derived additives; new asphalt, recycled asphalt, asphalt rejuvenator, and the heavy plastic-derived additives are melt-blended and kneaded according to a preset ratio to prepare heavy plastic-derived agent-modified recycled asphalt.

[0047] Step 3: Catalytic pyrolysis of the light plastics is performed to obtain carbon nanotubes and hydrogen-rich gas.

[0048] In the plastic waste recycling method provided by the embodiments of the present invention, first, the plastic waste is sorted. Based on the sorted heavy plastics and light plastics, modified asphalt, carbon nanotubes, and hydrogen-rich gas are respectively prepared; the segregation problem of plastic-modified asphalt can be solved, and at the same time, efficient recycling and high-value utilization of plastic waste can be achieved.

[0049] Further exemplarily, in Step 1, the plastic waste fragments can be sorted into heavy plastics and light plastics by using the wind density sorting method or the buoyancy density sorting method; among them, the plastics with a density greater than or equal to the first preset density threshold are heavy plastics, and the plastics with a density less than or equal to the second preset density threshold are light plastics; further specifically exemplarily, the first preset density threshold can be selected as 1.3 g·cm -3 , and the second preset density threshold can be 1.15 g·cm -3 .

[0050] Further exemplarily, in Step 2, the new asphalt, recycled asphalt, and the derived additives can be melt-blended and kneaded in a certain proportion by using melt mechanical blending; among them, the amine cracking agent is triethylenediamine or ethylenediamine ， The catalyst is sodium acetate or sodium carbonate.

[0051] Further exemplarily, in Step 3, the light plastics can be catalytically pyrolyzed by using a two-stage method to obtain carbon nanotubes and the by-product hydrogen-rich gas.

[0052] Exemplarily and optionally, in Step 1, before sorting the plastic waste to be recycled, the recycled plastic waste can be washed with clean water, crushed, and dried to obtain plastic waste fragments; and sorting treatment is performed based on the obtained plastic waste fragments.

[0053] In a further exemplary embodiment of the present invention, in step 2, in the step of catalytic amination cracking of heavy plastics using an amine cracking agent and a catalyst to obtain heavy plastic-derived additives, by mass: 5-10 parts of heavy plastics, 15-20 parts of ethylenediamine, 0.25-0.5 parts of sodium acetate; wherein, the amination cracking reaction temperature is 80°C to 110°C, and the reaction proceeds until the amination cracking is completely finished. Further specifically explanatory, the heavy plastic particles, the amine cracking agent, and the catalyst are added to the amination cracking reaction device according to the above ratio range; wherein, the addition amount of the amine cracking agent needs to ensure that the catalyst is completely dissolved and covers the heavy plastic particles to ensure that the heavy plastic particles are fully wetted. The device is gradually heated to the reaction temperature and continuously stirred, and the amination cracking reaction temperature is between 80°C and 110°C; it should be noted that a higher temperature can promote the amination cracking reaction, but if the temperature is too high, the amine cracking agent will volatilize in large amounts, so this reaction temperature range is limited. When the solution is uniform and the amination cracking is completely finished, the heating can be stopped, the reactor is cooled to room temperature, the solid product therein is collected and dried by ventilation, and the dried solid is crushed to obtain heavy marine plastic-derived additive particles.

[0054] In a further exemplary embodiment of the present invention, in step 2, when the brand-new asphalt, the aged recycled asphalt, the asphalt rejuvenator and the heavy plastic-derived additive are melt-kneaded and mixed in a certain proportion, calculated by mass, the preparation raw materials include the following components: 60-120 parts of aged asphalt, 40-80 parts of new asphalt, 10-20 parts of RA101 type asphalt rejuvenator, and 1 wt% - 4 wt% of heavy marine plastic-derived additive particles. Further specifically explanatory, aged asphalt and new asphalt are added to the kneader at 210°C to 240°C, and stirred at a stirring speed of 250 r / min to 350 r / min. The blended asphalt is heated to a molten state and fully mixed. Then, the rejuvenator is added to the kneader and stirred for another 20 min to 30 min, and the viscosity of the blend is adjusted to 1.8 Pa·s to 2.3 Pa·s to obtain the recycled asphalt binder. The recycled asphalt binder is cooled and continuously stirred at the original stirring speed. When the temperature is cooled to 150°C to 180°C, the heavy marine plastic-derived additive particles are added, the stirring speed is increased to 600 r / min to 650 r / min, and stirred for 10 min to 20 min to obtain the heavy marine plastic-derived additive modified recycled asphalt. Among them, when adding the heavy marine plastic-derived additive particles, there is an upper limit to the temperature of the recycled asphalt binder to avoid denaturation of the heavy marine plastic-derived additive particles, and the stirring speed needs to be increased to ensure uniform mixing in a short time.

[0055] Exemplarily, in step 3 of the embodiment of the present invention, first dissolve Fe(NO3)3·9H2O in an ethanol solvent, then add γ-Al2O3 to the prepared solution to form a suspension, and obtain an Fe / γ-Al2O3 cracking catalyst after drying, calcining and grinding; wherein, by mass, 0.5-1.0 parts of Fe(NO3)3·9H2O, 2-4 parts of ethanol solvent, and 0.5-1.0 parts of γ-Al2O3;

[0056] Then add the light plastic particles and the cracking catalyst into a fixed-bed cracking reactor in a ratio of (4-20):1, set the heating rate of the fixed-bed reactor to 5 °C / min, heat up to 500 °C - 600 °C, and at the same time introduce a protective atmosphere N2 into the reactor, keep the temperature for 1.5-2 hours, and the light plastic fragments will undergo a pyrolysis reaction as the temperature inside the reactor rises to obtain pyrolysis reaction gas;

[0057] Connect the gas outlet of the fixed-bed reactor to a catalytic reforming reactor, place a Ni-Al2O3 metal catalyst in the catalytic reforming reactor, set the heating rate of the catalytic reforming reactor to 10 °C / min, heat up to 800 °C - 1000 °C, keep the temperature for 1-1.5 hours, and at the same time introduce a protective atmosphere N2 to carry out a catalytic reaction on the pyrolysis gas. After the reaction, the pyrolysis product is converted into carbon nanotubes and hydrogen-rich gas; wherein, by mass, 5-10 parts of light plastic and 0.5-1.0 parts of Ni-Al2O3 metal catalyst.

[0058] Further explanation of the invention points of the embodiment of the present invention: The heavy plastics in plastic waste are used to prepare heavy plastic-derived additives through catalytic amine cracking, and the derived additives are used to enhance the stability, corrosion resistance, physical properties, etc. of recycled asphalt, and solve the segregation problem of plastic-modified asphalt; the light plastics in plastic waste are prepared into carbon nanotubes and hydrogen-rich gas through a two-stage catalytic pyrolysis method, providing a cheap carbon source for the preparation of carbon nanotubes with unrestricted source and transportation. At the same time, this method has the advantages of high carbon conversion rate and simple synthesis process. In the embodiment of the present invention, through the wind density sorting of plastic waste and the above two recovery methods, the efficient recovery and high-value utilization of plastic waste are completed.

[0059] Please refer to Figures 2 to 4 , a method for the efficient recovery and utilization of marine plastic waste provided by the embodiment of the present invention, comprising the following steps:

[0060] First, rinse, crush and dry the recovered marine plastic waste to obtain marine plastic waste fragments;

[0061] Secondly, the marine plastic waste fragments are sorted into heavy marine plastics and light marine plastics by wind density separation method. Among them, the heavy marine plastics are catalytically aminated with amine cracking agent and catalyst to obtain heavy marine plastic-derived additives, and the new asphalt, recycled asphalt and the derived additives are melt-mixed by melting mechanical blending according to a certain ratio to obtain heavy marine plastic-derived agent modified recycled asphalt. Among them, the light marine plastics are pyrolyzed by a two-stage catalytic method to produce carbon nanotubes and by-product hydrogen-rich gas. Explanatorily, there are various plastics in marine plastic waste, such as low-density polyethylene (LDPE, mainly used for making plastic bags and plastic films, widely used in food packaging, etc.), polystyrene (PPS, commonly used for making foam plastics), polypropylene (PP, with very wide applications, can be used for making various containers), and polyethylene terephthalate (PET, mainly used for making polyester fibers and beverage bottles, etc.). In order to achieve the efficient recycling and utilization of marine plastic waste, it is necessary to classify and recycle marine plastic waste. In addition, if the old asphalt mixture is to be recycled, the performance regeneration of asphalt should be considered.

[0062] Specifically and explanatorily, how to achieve the clean and high-value utilization of marine waste plastics has important engineering significance for reducing marine white pollution and bringing resource-saving benefits. The above embodiments of the present invention provide a method for the efficient recycling and utilization of marine plastic waste. First, the recycled marine plastic waste is washed, crushed and dried by clean water to obtain dry marine plastic fragments, and then the fragments are separated into heavy marine plastics and light marine plastics by wind density separation method. Then, the recycled heavy marine plastics are modified by catalytic amination technology, and the products are dried and pulverized to obtain heavy marine plastic-derived additives. Then, the heavy marine plastic-derived additives are mixed with molten recycled asphalt to obtain recycled modified asphalt. Secondly, the light marine plastics are treated by pyrolysis process to co-produce carbon nanotubes and hydrogen-rich gas. The present invention realizes the classified recycling and efficient utilization of marine plastic waste and alleviates the problem of marine environmental pollution.

[0063] Further explanatorily, the embodiments of the present invention combine the modification of waste plastics with the recycling and reuse of aged asphalt, which not only solves the problem of white garbage pollution but also solves the problem of performance degradation caused by asphalt aging. Among them, the heavy plastic components in marine plastic waste (with a higher density, greater than 1.3 g·cm -3 and mainly composed of PET plastics) are prepared into derived additives by catalytic amination. Its properties are more stable. When mixed with recycled asphalt, it can effectively improve the high-temperature performance and storage stability of recycled asphalt and extend the service life of recycled asphalt. In addition to removing the heavy components, the light plastic components in marine plastic waste (with a lower density, less than 1.15 g·cm -3And the main components are PA, PP plastics, etc.) also need to be efficiently recycled, and thermal decomposition recycling can pyrolyze and gasify these lightweight plastic components, effectively converting them into high value-added products. In recent years, many researchers have tried to prepare hydrogen from waste plastics as ammonia sources. Researchers have also found that waste plastics can also be used as a source of carbon materials under suitable catalysts. Carbon nanotubes, as an emerging material that can be synthesized using hydrocarbons, have excellent mechanical, thermal and electrical properties. In fields that require low density, low weight, high tensile strength or elastic modulus (such as transportation, structural materials, high-tech applications, etc.), carbon nanotubes are ideal application materials. The traditional synthesis of carbon nanotubes uses aromatic compounds (such as toluene, benzene, etc.), ethylene, etc. These petroleum by-products are controlled, limited in source, and inconvenient in transportation. The lightweight plastic components in marine plastic waste can be used to produce carbon nanotubes and their high value-added byproducts such as hydrogen through catalytic thermal cracking, which can make full use of their rich carbon and hydrogen elements, solve the problem of limited sources of raw materials for carbon nanotube synthesis, and complete the recycling of remaining marine plastic waste, which has important application value.

[0064] Example 1

[0065] The embodiment of the present invention is to prepare heavy marine plastic derived additive regenerated modified asphalt, wherein the modified regenerated asphalt, calculated by weight, comprises the following components in its preparation raw materials:

[0066] 80 parts of recycled asphalt (selected from asphalt recycled from a highway in Shaanxi), 70 parts of new asphalt (its softening point is 48.5℃, the needle penetration at 25℃ is 63dmm, the elongation at 15℃ is greater than 100cm, and the Brookfield rotation viscosity at 135℃ is 0.450Pa·s), 10 parts of RA101 asphalt regeneration agent, 5 parts of heavy marine plastics after wind-sorted marine plastic waste, 20 parts of ethylenediamine, and 0.25 parts of catalyst sodium acetate;

[0067] The preparation method for synthesizing the heavy marine plastic-derived additive-modified recycled asphalt according to the embodiment of the present invention comprises the following steps:

[0068] Step 1: Use recycled marine plastic waste to classify, rinse with clean water and break into pieces of 16-25mm 2 The large and small fragments are dried at 65-85°C for 30 minutes to obtain completely dried marine plastic debris fragments; and they are divided into heavy marine plastic debris and light marine plastic debris by wind density sorting method;

[0069] Step 2: Add heavy marine plastic fragments into the reactor, add excessive ethylenediamine and 0.5 wt% catalyst sodium acetate, stir and heat at 105 °C until the solution is uniform and the amine cracking of heavy marine plastics is completed. Then stop heating, let the reactor cool to room temperature, collect the solid product therein, ventilate and dry it, and then crush it to obtain heavy marine plastic-derived additive particles;

[0070] Step 3: Add aged asphalt and new asphalt into the internal mixer, raise the temperature to 230 °C, adjust the stirring speed to 300 r / min, heat and blend until the asphalt becomes molten. Add the regenerant into the internal mixer, continue to stir for 30 min and adjust the viscosity of the blend to 2.0 Pa·s to obtain the regenerated asphalt binder;

[0071] Step 4: Stop heating and stirring the regenerated asphalt binder and keep it in a molten state. Wait for the regenerated asphalt to cool down to 160 °C, add heavy marine plastic-derived additive particles equivalent to 1% of the mass of the asphalt, adjust the stirring speed to 600 r / min, and continuously stir for 10 min to obtain the heavy marine plastic-derived additive modified regenerated asphalt binder.

[0072] To fully understand the performance of the heavy marine-derived additive modified regenerated asphalt, physical property tests were carried out on the 1 wt% heavy marine plastic-derived agent modified regenerated asphalt in accordance with the "Test Procedures for Bitumen and Bituminous Mixtures for Highway Engineering" (JTJ E20 - 2011). The softening point of the 1 wt% heavy marine plastic-derived additive modified regenerated asphalt is 49.5 °C, the penetration at 25 °C is 61 dmm, and the Brookfield rotational viscosity at 135 °C is 0.50 Pa·s, meeting the relevant requirements of the "Technical Specifications for Construction of Highway Asphalt Pavement".

[0073] Example 2

[0074] Example 2 of the present invention is basically the same as Example 1, except that: in the preparation process of the heavy marine plastic-derived additive modified regenerated asphalt, the addition amount of the heavy marine plastic-derived additive particles is 2 wt%.

[0075] Measured under the same test conditions, the softening point of the 2 wt% heavy marine plastic-derived additive modified regenerated asphalt is 50.1 °C, the penetration at 25 °C is 59 dmm, and the Brookfield rotational viscosity at 135 °C is 0.54 Pa·s.

[0076] Example 3

[0077] Example 3 of the present invention is basically the same as Example 1, except that: in the preparation process of the heavy marine plastic-derived additive modified regenerated asphalt, the addition amount of the heavy marine plastic-derived additive particles is 3 wt%.

[0078] Measured under the same test conditions, the softening point of the recycled asphalt modified with 3 wt% heavy marine plastic-derived additive is 50.6 °C, the penetration at 25 °C is 57 dmm, and the Brookfield rotational viscosity at 135 °C is 0.59 Pa·s.

[0079] Example 4

[0080] Example 2 of the present invention is basically the same as Example 1, except that: in the preparation process of the recycled asphalt modified with heavy marine plastic-derived additive, the addition amount of heavy marine plastic-derived additive particles is 4 wt%.

[0081] Measured under the same test conditions, the softening point of the recycled asphalt modified with 4 wt% heavy marine plastic-derived additive is 51.0 °C, the penetration at 25 °C is 56 dmm, and the Brookfield rotational viscosity at 135 °C is 0.63 Pa·s.

[0082] Comparative Example 1

[0083] Comparative Example 1 is basically the same as Example 1, except that: the addition amount of heavy marine plastic-derived additive particles is 0 wt% (i.e., no heavy marine plastic-derived additive particles are added).

[0084] Measured under the same test conditions, the softening point of the recycled asphalt with 0 wt% heavy marine plastic-derived additive is 48.9 °C, the penetration at 25 °C is 65 dmm, and the Brookfield rotational viscosity at 135 °C is 0.47 Pa·s.

[0085] Specifically and explanatorily, to further intuitively illustrate the comparison situation of the above Examples 1 to 4 and Comparative Example 1, the test results of the recycled asphalt modified with different heavy marine plastic-derived additives are shown in Table 1.

[0086] Table 1. Test results of recycled asphalt modified with different heavy marine plastic-derived additives

[0087]

[0088] Based on the data in Table 1, it can be seen that the softening points of the heavy marine plastic-derived additive modified recycled asphalt in Comparative Example 1, Example 1, Example 2, Example 3, and Example 4 are increased by 0.4 °C, 1.0 °C, 1.6 °C, 2.1 °C, and 2.5 °C respectively compared with the base asphalt, and their penetration degrees are decreased by 2 dmm, 6 dmm, 8 dmm, 10 dmm, and 11 dmm respectively compared with the base asphalt, meeting the relevant requirements of the "Technical Specification for Construction of Highway Asphalt Pavement", indicating that the incorporation of the heavy marine plastic-derived additive can significantly improve the high-temperature performance of asphalt, and with the increase of the dosage of the heavy marine plastic-derived additive, the viscosity of the modified recycled asphalt will increase accordingly. In summary, using the amine-cracked heavy marine plastic as a modifier can not only be effectively mixed at the mixing temperature of recycled asphalt, but also further improve the comprehensive performance of recycled asphalt; considering other physical properties and the economic benefits of modified recycled asphalt, the present invention embodiment also focuses on protecting the optimal dosage of the heavy marine plastic-derived additive of 3 wt%.

[0089] Example 5

[0090] Please refer to Figure 4 , in Example 5 of the present invention, a method for preparing carbon nanotubes and by-product hydrogen-rich gas using marine plastic as a carbon source is provided, including:

[0091] Calculated by mass fraction, the preparation raw materials include the following components: 5 parts of light plastics after wind sorting of marine plastic waste, 0.5 part of Ni-Al2O3 metal catalyst, 0.5 part of Fe(NO3)3·9H2O, 2 parts of ethanol solvent, and 0.5 part of γ-Al2O3;

[0092] Step 1: Classify the recycled marine plastic waste, rinse it with clean water and crush it into fragments with a size of 16 - 25 mm, dry it at a temperature of 65 - 85 °C for 30 minutes to obtain completely dry marine plastic waste fragments; and classify them into heavy marine plastics and light marine plastics by the wind density separation method; 2 Step 2: Prepare the Fe / γ-Al2O3 catalyst by the impregnation method; first, dissolve Fe(NO3)3·9H2O in the ethanol solvent, then add γ-Al2O3 to the prepared solution to form a suspension, and obtain the Fe / γ-Al2O3 cracking catalyst after drying, calcination, and grinding;

[0093] Step 3: Add the dried light plastics and the cracking catalyst into the fixed-bed cracking reactor at a ratio of 20:1, set the heating rate of the fixed-bed reactor to 5 °C / min, heat it to 600 °C, and simultaneously introduce the protective atmosphere N2 into the reactor, keep it warm for 1.5 hours, and the light marine plastic fragments will undergo pyrolysis reactions as the temperature inside the reactor rises;

[0094] Step 4: After the reaction is completed, cool the reactor to room temperature, and collect the carbon nanotubes and hydrogen-rich gas generated during the reaction;

[0095] Step 4: Connect the gas outlet of the fixed-bed reactor to the catalytic reforming reactor. Place the Ni-Al2O3 metal catalyst in the catalytic reforming reactor. Set the heating rate of the catalytic reforming reactor to 10 °C / min and heat it to 800 °C, then hold the temperature for 1 hour. Meanwhile, introduce the protective atmosphere N2 to carry out the catalytic reaction on the pyrolysis gas. After the reaction, the pyrolysis products are converted into carbon nanotubes and hydrogen-rich gas.

[0096] Example 6

[0097] Example 6 of the present invention is basically the same as Example 5, except that: in Step 3, the addition ratio of the light plastic particles to the Fe / γ-Al2O3 catalyst is 10:1.

[0098] Example 7

[0099] Example 7 of the present invention is basically the same as Example 5, except that: in Step 3, the addition ratio of the light plastic particles to the Fe / γ-Al2O3 catalyst is 5:1.

[0100] Example 8

[0101] Example 8 of the present invention is basically the same as Example 5, except that: in Step 3, the addition ratio of the light plastic particles to the Fe / γ-Al2O3 catalyst is 4:1.

[0102] Example 9

[0103] Example 9 of the present invention is basically the same as Example 5, except that: in Step 4, the temperature in the fixed-bed cracking reactor is raised to 850 °C.

[0104] Example 10

[0105] Example 10 of the present invention is basically the same as Example 5, except that: in Step 4, the temperature in the fixed-bed cracking reactor is raised to 900 °C.

[0106] Example 11

[0107] Example 11 of the present invention is basically the same as Example 5, except that: in Step 4, the temperature in the fixed-bed cracking reactor is raised to 1000 °C.

[0108] Based on Examples 5 to 11, to further illustrate the problem intuitively, the test results of the carbon conversion rate of the carbon nanotubes are shown in Table 2.

[0109] Table 2. Test results of the carbon conversion rate of the carbon nanotubes

[0110]

[0111]

[0112] As can be seen from the carbon conversion rates shown in Table 2, good results can be obtained in the above embodiments. However, due to the different usage amounts of the Fe / γ-Al2O3 cracking catalyst in Step 3 and the different cracking temperatures in Step 3, there are differences in the carbon conversion rates of the carbon nanotubes prepared from pyrolyzed light marine plastics. This shows that the carbon conversion rate of the carbon nanotubes first increases and then decreases with the increase in the usage amount of the cracking catalyst, and first increases and then decreases with the increase in the cracking temperature. There are preferred usage amounts of the cracking catalyst and waste plastic cracking temperatures during the preparation of carbon nanotubes.

[0113] Example 12

[0114] A method for recycling plastic waste provided by an embodiment of the present invention includes the following steps:

[0115] Step 1: Sort the plastic waste to be recycled to obtain heavy plastics and light plastics; among them, the sorting method used is the wind density sorting method;

[0116] Step 2: Catalytically amine crack the heavy plastics to obtain heavy plastic-derived additives; melt, mix, and knead virgin asphalt, recycled asphalt, asphalt rejuvenator, and the heavy plastic-derived additives in a preset ratio to prepare a heavy plastic-derived additive-modified recycled asphalt; among them, the amine cracking agent is triethylenediamine ； The catalyst is sodium acetate; the reaction temperature for catalytic amine cracking is 80°C; the preset ratio is, by mass, 40 parts of virgin asphalt, 60 parts of recycled asphalt, 10 parts of asphalt rejuvenator, and 1 wt% of heavy marine plastic-derived additives; the melt mixing and kneading include: stirring the recycled asphalt and virgin asphalt at 210°C, heating and blending the asphalt to a molten state and fully mixing; then, adding the asphalt rejuvenator and continuing to stir and adjusting the viscosity of the blend to 1.8 Pa·s to obtain a recycled asphalt binder; gradually cooling the recycled asphalt binder and continuously stirring, adding heavy marine plastic-derived additive particles when the temperature drops to 150°C, and stirring to obtain a heavy marine plastic-derived additive-modified recycled asphalt;

[0117] Step 3: Catalytically pyrolyze the light plastics to obtain carbon nanotubes and hydrogen-rich gas. Among them, the two-stage method is adopted for catalytic pyrolysis of light plastics, including: dissolving Fe(NO3)3·9H2O in an ethanol solvent, then adding γ-Al2O3 to form a suspension, drying, calcining, and grinding to obtain an Fe / γ-Al2O3 cracking catalyst. Among them, by mass fraction, 0.5 parts of Fe(NO3)3·9H2O, 2 parts of ethanol solvent, and 0.5 parts of γ-Al2O3; under a N2 protection atmosphere, catalytic pyrolysis of light plastic particles and the Fe / γ-Al2O3 cracking catalyst is carried out at a temperature of 500°C. Among them, by mass fraction, the proportional relationship between light plastics and the Fe / γ-Al2O3 cracking catalyst is 4:1; under a N2 protection atmosphere, the pyrolysis gas obtained by catalytic pyrolysis is catalytically reformed using a Ni-Al2O3 metal catalyst at a temperature of 800°C to obtain carbon nanotubes and hydrogen-rich gas.

[0118] Example 13

[0119] A method for recycling plastic waste provided by an embodiment of the present invention includes the following steps:

[0120] Step 1: Sort the plastic waste to be recycled to obtain heavy plastics and light plastics. Among them, the sorting method used is the buoyancy density sorting method.

[0121] Step 2: Catalytically amine crack the heavy plastics to obtain heavy plastic-derived additives; melt, mix, and knead virgin asphalt, recycled asphalt, asphalt rejuvenator, and the heavy plastic-derived additives in a preset ratio to obtain heavy plastic-derived additive-modified recycled asphalt. Among them, the amine cracking agent is ethylenediamine. ； The catalyst is sodium carbonate; the reaction temperature for catalytic amine cracking is 95°C; the preset ratio is, by mass fraction, 50 parts of virgin asphalt, 80 parts of recycled asphalt, 15 parts of asphalt rejuvenator, and 3 wt% of heavy marine plastic-derived additives added; the melt mixing and kneading includes: stirring recycled asphalt and virgin asphalt at 220°C, co-mixing and heating the asphalt to a molten state and fully mixing; then, adding the asphalt rejuvenator and continuing to stir and adjusting the viscosity of the blend to 2.0 Pa·s to obtain a recycled asphalt binder; gradually cooling the recycled asphalt binder and continuously stirring, adding heavy marine plastic-derived additive particles when the temperature drops to 170°C, and stirring to obtain heavy marine plastic-derived additive-modified recycled asphalt.

[0122] Step 3: Catalytically pyrolyze the light plastic to obtain carbon nanotubes and hydrogen-rich gas. Among them, the catalytic pyrolysis of the light plastic is carried out by a two-stage method, including: dissolving Fe(NO3)3·9H2O in an ethanol solvent, then adding γ-Al2O3 to form a suspension, drying, calcining, and grinding to obtain an Fe / γ-Al2O3 cracking catalyst. Among them, by mass, 0.8 parts of Fe(NO3)3·9H2O, 34 parts of ethanol solvent, and 0.8 parts of γ-Al2O3; under a nitrogen protection atmosphere, the light plastic particles and the Fe / γ-Al2O3 cracking catalyst are catalytically pyrolyzed at a temperature of 550°C. Among them, by mass, the ratio of the light plastic to the Fe / γ-Al2O3 cracking catalyst is 10:1; under a nitrogen protection atmosphere, the pyrolysis gas obtained by catalytic pyrolysis is catalytically reformed at a temperature of 900°C using a Ni-Al2O3 metal catalyst to obtain carbon nanotubes and hydrogen-rich gas.

[0123] Example 14

[0124] A method for recycling plastic waste provided by an embodiment of the present invention includes the following steps:

[0125] Step 1: Sort the plastic waste to be recycled to obtain heavy plastic and light plastic. Among them, the sorting method used is the wind density sorting method.

[0126] Step 2: Catalytically amine crack the heavy plastic to obtain a heavy plastic-derived additive; melt, mix, and knead the virgin asphalt, recycled asphalt, asphalt rejuvenator, and the heavy plastic-derived additive in a preset ratio to obtain a heavy plastic-derived agent-modified recycled asphalt. Among them, the amine cracking agent is triethylenediamine ； The catalyst is sodium carbonate; the reaction temperature of catalytic amine cracking is 110°C; the preset ratio is, by mass, 80 parts of virgin asphalt, 120 parts of recycled asphalt, 20 parts of asphalt rejuvenator, and 4 wt% of the heavy marine plastic-derived additive; the melt mixing and kneading includes: stirring the recycled asphalt and virgin asphalt at 240°C, co-blending and heating the asphalt to a molten state and fully mixing; then, adding the asphalt rejuvenator and continuing to stir and adjusting the viscosity of the blend to 2.3 Pa·s to obtain a recycled asphalt binder; gradually cooling the recycled asphalt binder and continuously stirring, adding the heavy marine plastic-derived additive particles when the temperature drops to 180°C, and stirring to obtain a heavy marine plastic-derived additive-modified recycled asphalt.

[0127] Step 3: Catalytic pyrolysis of the light plastic to obtain carbon nanotubes and hydrogen-rich gas; among them, the catalytic pyrolysis of the light plastic is carried out by a two-stage method, including: dissolving Fe(NO3)3·9H2O in an ethanol solvent, then adding γ-Al2O3 to form a suspension, drying, calcining, and grinding to obtain an Fe / γ-Al2O3 cracking catalyst; among them, by mass, 1.0 part of Fe(NO3)3·9H2O, 4 parts of ethanol solvent, and 1.0 part of γ-Al2O3; under a N2 protection atmosphere, the light plastic particles and the Fe / γ-Al2O3 cracking catalyst are catalytically pyrolyzed at a temperature of 600 °C; among them, by mass, the ratio of the light plastic to the Fe / γ-Al2O3 cracking catalyst is 20:1; under a N2 protection atmosphere, the pyrolysis gas obtained by catalytic pyrolysis is catalytically reformed using a Ni-Al2O3 metal catalyst at a temperature of 1000 °C to obtain carbon nanotubes and hydrogen-rich gas.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: the specific implementation manners of the present invention can still be modified or equivalently replaced, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for recycling plastic waste, characterized in that, It includes the following steps: Sort the plastic waste to be recycled to obtain heavy plastics and light plastics; among them, the plastic waste to be recycled is marine plastic waste, and plastics with a density greater than 1.3 g·cm -3 are used as heavy plastics, and plastics with a density less than 1.15 g·cm -3 are used as light plastics; Carry out catalytic aminolysis on the heavy plastic to obtain a heavy plastic-derived additive; melt, mix and knead brand-new asphalt, recycled asphalt, asphalt rejuvenator and the heavy plastic-derived additive in a preset ratio to prepare a heavy plastic-derived agent-modified recycled asphalt; wherein, in the step of carrying out catalytic aminolysis on the heavy plastic to obtain a heavy plastic-derived additive, the aminolysis agent is triethylenediamine or ethylenediamine ； The catalyst is sodium acetate or sodium carbonate; the reaction temperature of catalytic aminolysis is 80°C to 110°C; Catalytically pyrolyze the light plastic to obtain carbon nanotubes and hydrogen-rich gas; among them, the catalytic pyrolysis of the light plastic by a two-stage method includes: dissolving Fe(NO3)3·9H2O in an ethanol solvent, then adding γ-Al2O3 to form a suspension, drying, calcining, and grinding to obtain an Fe / γ-Al2O3 cracking catalyst; among them, by mass, 0.5 to 1.0 parts of Fe(NO3)3·9H2O, 2 to 4 parts of ethanol solvent, and 0.5 to 1.0 parts of γ-Al2O3; under a nitrogen protection atmosphere, the light plastic particles and the Fe / γ-Al2O3 cracking catalyst are catalytically pyrolyzed at a temperature of 500°C to 600°C; among them, by mass, the proportion of the light plastic to the Fe / γ-Al2O3 cracking catalyst is (4 to 20):1; under a nitrogen protection atmosphere, the pyrolysis gas obtained by catalytic pyrolysis is catalytically reformed at a temperature of 800°C to 1000°C using a Ni-Al2O3 metal catalyst to obtain carbon nanotubes and hydrogen-rich gas.

2. The method for recycling plastic waste according to claim 1, characterized in that, In the step of sorting the plastic waste to be recycled to obtain heavy plastic and light plastic, The sorting method used is the wind density sorting method or the buoyancy density sorting method.

3. A method for recycling plastic waste according to claim 1, characterized in that, In the step of melting, mixing and kneading the virgin asphalt, recycled asphalt, asphalt rejuvenator and the heavy plastic-derived additive in a preset ratio to obtain the heavy plastic-derived agent modified recycled asphalt, The preset ratio is, by mass, 40 to 80 parts of virgin asphalt, 60 to 120 parts of recycled asphalt, 10 to 20 parts of asphalt rejuvenator, and the addition amount of the heavy marine plastic-derived additive is 1 wt% to 4 wt%.

4. A method for recycling plastic waste according to claim 3, characterized in that, In the step of melting, mixing and kneading the virgin asphalt, recycled asphalt, asphalt rejuvenator and the heavy plastic-derived additive in a preset ratio to obtain the heavy plastic-derived agent modified recycled asphalt, The melting, mixing and kneading include: stirring the recycled asphalt and the virgin asphalt at 210°C to 240°C, blending and heating the asphalt to a molten state and fully mixing; then, adding the asphalt rejuvenator and continuing to stir and adjusting the viscosity of the blend to 1.8 Pa·s to 2.3 Pa·s to obtain a recycled asphalt binder; gradually cooling the recycled asphalt binder and continuously stirring, and adding the heavy marine plastic-derived additive particles when the temperature is cooled to 150°C to 180°C, and stirring to obtain the heavy marine plastic-derived additive modified recycled asphalt.

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