Aromatic hydrocarbon production method by coupling conversion of CO2 and polyolefins

Abstract

This invention discloses a method for producing aromatic hydrocarbons by coupling conversion of carbon dioxide and polyolefin, and belongs to the technical field of conversion and reuse of polyolefin plastics. The catalyst is a dual-function catalyst consisting of a metal, a metal oxide, and a molecular sieve, and the conversion reaction is carried out under the action of the catalyst using carbon dioxide and polyolefin as reaction raw materials. The reaction process not only enables the resource utilization of carbon dioxide, but also enables the recycling of polyolefin plastics, realizing high value-added utilization and producing high value-added aromatic hydrocarbon products. The reaction has very high product yield and product selectivity, with the yield of aromatic hydrocarbons reaching 50-80%, and the proportion of benzene, toluene, and xylene in the aromatic hydrocarbons being 60% or more. Furthermore, the catalyst can be reused after simple regeneration treatment, and it has high applicability as a new technology for the comprehensive utilization of polyolefin waste plastics and the reduction of carbon dioxide emissions.

Description

[Technical Field]

[0001] The present invention belongs to the technical field of producing high-value chemical products such as aromatic hydrocarbons by coupling conversion of CO2 and polyolefin-based plastics, and more specifically, relates to a catalyst and a method for producing aromatic hydrocarbons by coupling conversion of CO2 and polyolefins. [Background technology]

[0002] Plastics are important organic synthetic polymer materials and are widely used in various fields such as packaging, agriculture, construction, and automobiles. By 2019, the annual global production of plastics had already reached 460 million tons, making it one of the most produced synthetic materials. Of this, polyolefin plastics, represented by polyethylene and polypropylene, account for approximately 55% of the total plastic production. However, because polyolefins are chemically inert, large quantities of them are used in single-use products, and recycling remains difficult. The serious environmental pollution problems caused by this have already attracted the attention of researchers.

[0003] In polyolefins, the C(sp) on their skeleton 3 )-C(sp 3 The C-C bond is very stable and difficult to break. Therefore, when recovering polyolefins, it is necessary to introduce additional energy to break the C-C bond. However, in conventional polyolefin recovery technologies, such as pyrolysis and hydrolysis, the breaking of the C-C bond is random and disordered, and the resulting product is a pyrolysis oil mainly composed of long-chain alkanes or alkenes. This product has a wide boiling point range, relatively low added value, and cannot selectively produce high-value-added products. For this reason, there is a lack of economically viable driving force for the pyrolysis of plastics.

[0004] CO2 is a type of greenhouse gas, and with the clear proposal of carbon emission peak-out and carbon neutrality ("dual carbon targets"), how to reduce CO2 emissions has become an extremely important research area. Furthermore, developing efficient catalytic technologies to convert CO2 into high-value chemicals using CO2 as a C1 resource is an important direction for the resource utilization of CO2 and has significant implications for achieving dual carbon targets and the sustainable development of society. However, due to the linear geometric structure of the CO2 molecule and the high bond energy of the C=O double bond (~799 kJ / mol), catalytic conversion of CO2 is extremely difficult. Therefore, realizing the efficient conversion and utilization of CO2 also has important academic significance. Some studies have shown that high-value chemicals and liquid fuels (e.g., low-carbon olefins, aromatic hydrocarbons, or higher alcohols) can be produced under high temperature and pressure using CO2 and H2, but at present, the acquisition of H2 resources is extremely dependent on the consumption of fossil energy (coal, oil, and natural gas). In the absence of superior "green hydrogen" acquisition technologies, using large quantities of H2 resources means emitting more CO2. Therefore, achieving the utilization of CO2 as a resource without using hydrogen is both more appealing and a greater challenge.

[0005] Aromatic hydrocarbons, particularly benzene, toluene, and xylene (BTX), are essential raw materials for the organic chemical industry with high demand, and are generally obtained by catalytic reforming and rectification of naphtha. Obtaining aromatic hydrocarbons under mild conditions by catalytic pyrolysis using waste polyolefins as raw materials is an economically viable technique. Zhang et al. at the University of California, Santa Barbara, converted polyolefins to long-chain alkyl aromatic hydrocarbons by reacting them at 280°C for 24 hours using a Pt / γ-Al2O3 catalyst, achieving a yield of over 70% of aromatic hydrocarbons. Although this method enables conversion at a mild temperature such as 280°C, the product contains very little benzene, toluene, and xylene, which have higher added value (Non-Patent Document 1). Patent Document 1 discloses a method for producing aromatic hydrocarbons, synthesis gas, olefins, and carbon materials by coupling the pyrolysis of waste plastics with carbon dioxide reduction, and by simultaneously supplying flue gas and waste plastics and performing high-temperature pyrolysis, aromatic hydrocarbon products can be obtained. However, this method requires relatively high reaction temperatures; while the claims specify 300-800°C, all the examples show reaction temperatures above 600°C. High reaction temperatures mean high energy input and heat dissipation, which increases the energy consumption of the reaction, and potentially the cost of energy input may exceed the product value. Producing high value-added aromatic hydrocarbons by coupling conversion reactions of CO2 with polyolefins and plastics at relatively low temperatures, such as below 300°C, remains a challenge. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Chinese Patent Application Publication No. 115161051 Specification [Non-patent literature]

[0007] [Non-Patent Document 1] Fan Zhang et al. Science 370(2020)437-441 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] This invention has been made in view of the above-mentioned problems, and provides a catalyst and a method for producing aromatic hydrocarbons by coupling conversion of CO2 and polyolefin. [Means for solving the problem]

[0009] The technical means of the present invention are as follows: The present invention provides a catalyst for producing aromatic hydrocarbons by coupling conversion of carbon dioxide and polyolefin, wherein the catalyst is a binary functional catalyst consisting of a metal and a molecular sieve, and the conversion reaction is carried out in a kettle reactor under the action of the catalyst using carbon dioxide and polyolefin as reaction raw materials. The catalyst is a binary functional catalyst in which one functional component consists of a metal, a metal oxide, or both, and the other functional component consists of a molecular sieve, wherein the metal or metal oxide component exhibits an effect of activating CO2, and the molecular sieve exhibits an effect of activating polyolefin, and the combination method of the metal or metal oxide and the molecular sieve is physical mixing or support, and the molecular sieve is a molecular sieve having MFI, MEL, and MWW topological structures.

[0010] In the above technical means, preferably, the metal or metal oxide comprises one or more elements from Fe, Co, Ni, Mn, Ce, Cu, Ru, Zn, Ga, Rh, Pd, Ir, and Pt, and the mass fraction of the metal or metal oxide to the binary functional catalyst is 0.1 wt% to 60 wt%, preferably 0.5 wt% to 50 wt%.

[0011] In the above technical means, preferably, the metal or metal oxide is directly supported on the molecular sieve, or the metal or metal oxide is dispersed on a metal oxide support and then physically mixed with the molecular sieve to constitute a binary functional catalyst, wherein the metal oxide support is Al2O3, TiO2, CeO2, ZnO, MoO x , MnO x Includes one or more of the following.

[0012] In the above technical means, preferably, the skeletal elements of the molecular sieve having the MFI, MEL, and MWW topological structures include at least one of Si-O, Si-O-Al, Si-O-Al-P, Si-O-Al-B, and Si-O-Al-Ge, and preferably the molecular sieve having the MFI, MEL, and MWW topological structures is at least one of MCM-22, ZSM-11, or ZSM-5.

[0013] In the above technical means, preferably, the molecular sieve having the MFI, MEL, and MWW topological structures contains a moderate acid, and the amount of moderate acid sites is ≥0.1 mol / kg, preferably ≥0.2 mol / kg, and more preferably ≥0.25 mol / kg.

[0014] The acid strength is defined by the NH3-TPD peak, and there are three levels of acidity: weak, medium-strong, and strong. The NH3-TPD corresponds to the position of the NH3 desorption peak. The position of the desorption peak is determined by recording the thermal conduction signal of NH3 desorption with a TCD under standard test conditions, i.e., the ratio of sample mass w to carrier gas flow rate f (w / f) = 100 g·h / L and the heating rate 10 °C / min, drawing a desorption curve, and classifying the inorganic solid into three levels of acid strength according to the peak position of the curve. A weak acid refers to an acidic site where the NH3 desorption temperature is less than 245 °C, a medium-strong acid refers to an acidic site where the NH3 desorption temperature is between 275 and 500 °C, and a strong acid refers to an acidic site where the NH3 desorption temperature is greater than 500 °C. The molecular sieve may be synthesized in the laboratory or commercially purchased, as long as it satisfies the requirements of the present invention.

[0015] In the above technical means, preferably, the metal or the metal oxide is complexed with the molecular sieve by an impregnation method, a deposition precipitation method, a vapor deposition method, or physical mixing.

[0016] In the above technical means, preferably, the dual-functional catalyst is pre-reduced, and the pre-reduction conditions are that the reduction atmosphere is H2 or CO, etc., the reduction temperature is 300°C to 500°C, and the reduction time is 0.5 h to 10 h.

[0017] In the above technical means, the present invention further provides a method for producing aromatic hydrocarbons by coupling conversion of carbon dioxide and polyolefin-based plastics. Using carbon dioxide and polyolefin-based plastics as reaction raw materials, and using the catalyst obtained by the above technical means, when the reaction is carried out in a batch reactor, the residence time of the reactants is 0.5 to 20 h, and when the reaction is carried out in a moving bed reactor, the gas hourly space velocity (GHSV) of the reaction is 20 to 2000 mL·g -1 ·h -1 is.

[0018] In the above technical means, preferably, the polyolefin-based plastic includes one or more of polyethylene, polypropylene, and polybutylene, and plastic products or used waste plastics processed from the polyolefin as raw materials.

[0019] In the above technical means, preferably, the pressure of the carbon dioxide is 0.2 to 6 MPa, preferably 0.5 to 3 MPa, the reaction temperature is 180 to 400°C, preferably 230 to 300°C, the mass ratio of the catalyst to the polyolefin is ≥1:500, preferably ≥1:100, and the reaction time is 0.5 to 20 h, preferably 1 to 10 h, more preferably 2 to 10 h.

Advantages of the Invention

[0020] According to the present invention, it has the following advantages. 1. Unlike conventional plastic pyrolysis techniques, the present invention utilizes a composite catalyst to couple CO2 with polyolefins in a single step, enabling highly selective conversion to high-value aromatic hydrocarbons such as benzene, toluene, and xylene. By adding CO2, it not only serves as a raw material for aromatic hydrocarbons but also reacts with H species generated by hydrogen transfer during the aromatization process, thereby suppressing the formation of alkanes and improving the selectivity of aromatic hydrocarbon components.

[0021] 2. Unlike the high-temperature thermal decomposition mechanism of polyolefins, at low temperatures (reaction temperature below 300°C), polyolefins cannot produce aromatic hydrocarbons through the dehydrogenation aromatization process (Equation 1), but can produce aromatic hydrocarbons solely through the hydrogen transfer aromatization process (Equation 2). Therefore, the yield of aromatic hydrocarbons at low temperatures is limited by its reaction mechanism and does not exceed 50%. [ka] [ka]

[0022] This invention utilizes hydrogen spillover between catalyst components to consume hydrogen leaked from the hydrogen transfer aromatization reaction of the molecular sieve using CO2, thereby preventing the formation of alkanes and disrupting the conventional reaction equilibrium. This allows for the highly selective production of high-value aromatic hydrocarbon products under relatively mild reaction conditions (reaction temperature below 300°C), making it highly applicable.

[0023] 3. The present invention uses polyolefin as a raw material. The polyolefin may be polyolefin itself, or plastic products made by processing polyolefin as a raw material, such as plastic bags, plastic containers, wraps, various films, and waste food packaging. Because the raw material has a wide supply source and high potential for use, this is an efficient and scalable method of utilizing polyolefin.

[0024] 4. The present invention can be applied not only to the resource utilization of low-concentration CO2 exhaust gases generated in processes such as petroleum refining, cement production, steelmaking, and power generation, but also to the resource utilization of high-concentration CO2 exhaust gases generated from lime kilns, oil field gases, and grain fermentation gases. Because the raw materials have a wide range of supply sources and high applicability, it can significantly promote the reduction of greenhouse gas CO2. For example, the CO2 content in exhaust gas from the steelmaking industry is approximately 6% to 18%, and this exhaust gas can be converted using the method of the present invention without separation or purification, thereby significantly saving separation costs.

[0025] 5. The catalyst of the present invention can be recycled after undergoing a regeneration process of air roasting and hydrogen reduction, without significant catalyst loss, and can greatly reduce cost problems caused by catalyst deactivation.

[0026] 6. The present invention not only provides a simple manufacturing process for the composite catalyst, operates under mild conditions, and simultaneously achieves high value-added utilization of polyolefins and CO2 during the reaction process, but also results in a product with high space-time yield and selectivity, with a yield of 50-80% for the mixed aromatic hydrocarbons, and the proportion of benzene, toluene, and xylene in the aromatic hydrocarbons being 60% or more. The yield of aromatic hydrocarbons is approximately twice that of the conventional thermal decomposition process of polyolefins under inert gas conditions. [Modes for carrying out the invention]

[0027] The present invention will be described in more detail below with reference to examples, but the scope of the claims of the present invention is not limited by these examples. Furthermore, the examples only illustrate some of the conditions for achieving this objective, and do not mean that this objective cannot be achieved unless these conditions are met.

[0028] 1. Manufacturing of molecular sieves In this invention, the moderately strong acid is measured by methods such as solid-state NMR H spectrum (1H NMR), NH3-TPD, infrared spectroscopy, and chemical titration. However, the method of measuring acidity is not limited to the methods described above.

[0029] The molecular sieves having the MFI, MEL, and MWW topological structures described in this invention can be produced by various methods and conditions, and in this invention, production by hydrothermal synthesis is described as an example.

[0030] 1) Molecular sieves having an MFI topology structure are manufactured by the following process. The oxide SiO2:Al2O3:Na2O:R:H2O = 5:0.02:2:1.5:200 (mass ratio) is used to weigh 30% silica sol (mass concentration), aluminum sulfate, sodium hydroxide, tetrapropylammonium hydroxide (R), and deionized water as raw materials. The mixture is stirred at 30°C and aged for 2 hours. After 2 hours, it is transferred to a hydrothermal reaction vessel and crystallized at 180°C for 48 hours. The mixture is rapidly cooled to room temperature in a water bath, and repeated centrifugal washing is performed until the pH of the supernatant reaches 7 at the end of centrifugal washing. The precipitate is dried at 110°C for 17 hours, and then roasted in an air atmosphere at 600°C for 3 hours to obtain a ZSM-5 molecular sieve with an MFI topology structure, which is used as component 1.

[0031] 2) Molecular sieves having a MEL topological structure are manufactured by the following process. Silica sol, aluminum isopropoxide, sodium hydroxide, TBAOH(R), and deionized water are weighed as raw materials in the oxide SiO2:Al2O3:Na2O:R:H2O = 10:0.3:1:2:200 (mass ratio). After stirring overnight at room temperature, the gel is placed in a 65°C oven to dry, then pulverized and placed in a crystallization vessel. A certain amount of deionized water is added, and crystallization is carried out at 170°C for 3 days. The resulting product is subjected to suction filtration, washing, drying, and ammonium exchange, and then roasted in a muffle oven at 600°C for 6 hours to obtain a ZSM-11 molecular sieve having a MEL topology structure, which is designated as component 2.

[0032] The framework element composition of the molecular sieve having the MFI, MEL, and MWW topological structures may be at least one of Si-O, Si-Al-O, Si-Al-P-O, Si-Al-B-O, and Si-Al-Ge-O.

[0033]

Table 1

[0034] 2. Preparation of Binary Functional Catalyst A binary functional catalyst is formed by compounding a metal and a molecular sieve by an impregnation method, a deposition-precipitation method, a vapor deposition method, or physical mixing. Here, for example, the binary functional catalyst is prepared by an impregnation method. The impregnation process can be carried out by either equal-volume impregnation or excess impregnation as follows. Dissolve the metal source in deionized water and place it in the precursor solution. Place the molecular sieve in the precursor solution and stir well to uniformly disperse the precursor solution and the solute therein in the molecular sieve. Then, obtain the molecular sieve modified with the necessary metal oxide by drying and calcination. When adopting the equal-volume impregnation method, it is necessary to measure the pore volume V p of the molecular sieve in advance. The volume of the precursor solution used is V0 = V p . When adopting the excess impregnation method, the volume of the precursor solution used is V0 < V p . The preparation of the catalyst and its parameter characteristics are specifically shown in Table 2-3.

[0035]

Table 2

[0036] 3. Examples of Catalytic Reactions The catalyst can be used in a batch reactor. In the reaction device, a gas flow meter is installed to control the gas flow rate, and quantitative analysis of the product is carried out using gas chromatography. Let's explain using a kettle reactor as an example. A fixed amount of catalyst and a fixed amount of polyolefin are mixed and placed in a kettle reactor. The air in the reactor is replaced with CO2, CO2 gas (containing 5% Ar as an internal standard for chromatographic analysis) is injected at 0.2 to 6 MPa, and the temperature is raised to 180°C to 300°C to carry out the reaction. The product is quantitatively analyzed by chromatography. The gas-phase product is analyzed using Ar as an internal standard, and the yield is calculated. After the liquid product is collected, it is analyzed using n-undecane as an internal standard, and the yield is calculated. The reaction performance can be altered by changing the reaction temperature, reaction pressure, and the mass ratio of CO2 to polyolefin supply. The performance is as follows: The total selectivity for aromatic hydrocarbons reaches 50-80%, with benzene, toluene, and xylene (BTX) accounting for more than 60% of the aromatic hydrocarbons. The addition of CO2 not only serves as a raw material for aromatic hydrocarbons, but also reacts with hydrogen species generated by hydrogen transfer during the aromatization process, thereby suppressing the formation of alkanes and improving the selectivity of aromatic hydrocarbon components. The applications of the catalyst and the data on its effects are specifically shown in Table 3.

[0037] [Table 3]

[0038] The metal component contained in catalyst L used in Comparative Example 1 and its manufacturing method are the same as those of catalyst A. The molecular sieve component used is replaced with a molecular sieve of component 5, which is commercially available at the Nankai University Catalyst Factory and has a three-dimensional 8-membered ring pore.

[0039] The metal components contained in catalyst M used in Comparative Example 2 and the method of its production are the same as those of catalyst A. The molecular sieve component used is replaced with a molecular sieve of component 6, which is commercially available at the Nankai University Catalyst Factory and has a three-dimensional 12-membered ring pore.

[0040] The metal component contained in catalyst N used in Comparative Example 3 and its manufacturing method are the same as those of catalyst A. The molecular sieve component used is replaced with a molecular sieve of component 7, which is commercially available at the Nankai University Catalyst Factory and has pores with coexistence of one-dimensional 8-membered rings and 12-membered rings.

[0041] The metal component contained in catalyst O used in Comparative Example 4 and its manufacturing method are the same as those of catalyst A. The molecular sieve component used is replaced with a molecular sieve of component 8, which is commercially available at the Nankai University Catalyst Factory and has a one-dimensional 10-membered ring pore.

[0042] The reaction results of Comparative Examples 1-4 demonstrate that molecular sieves with different topological structures significantly affect product selectivity. SAPO-34, with its three-dimensional 8-membered ring pore structure, is unfavorable for the conversion of polyolefins and the generation of aromatic hydrocarbon products, while being suitable for the generation of hydrocarbons with short carbon chains, resulting in an aromatic hydrocarbon yield of only 4%. The USY molecular sieve with its three-dimensional 12-membered ring pore has relatively large pore openings, which allows for the very easy generation of heavy aromatic hydrocarbons (e.g., naphthalene), which are then deactivated by coal accumulation. As a result, the yield of heavy aromatic hydrocarbons and coal accumulation is high, with heavy aromatic hydrocarbons accounting for 68% of all aromatic hydrocarbon products. The commercially available MOR molecular sieve with a coexistence of one-dimensional 8-membered and 12-membered rings, and the SAPO-11 molecular sieve with its one-dimensional 10-membered ring pore, are unfavorable for the aromatization process, producing mainly decomposed gasoline as the product, with a low aromatic hydrocarbon content and an aromatic hydrocarbon yield of only 21%.

[0043] The metal component contained in catalyst P used in Comparative Example 5 and its manufacturing method are the same as those of catalyst A, but the molecular sieve component used is replaced with the molecular sieve of component 9, and the acid density of its medium-strong acid is only 0.07 mmol / g. The reaction performance of Comparative Example 5 was extremely poor, which is probably because the acid density was extremely low, resulting in a very weak aromatization ability of the reaction. Therefore, a certain medium-strong acid density is very important.

[0044] The catalyst Q used in Comparative Example 6 was obtained by directly immersing Pt in γ-Al2O3. As a result, almost no CO2 was converted, the conversion rate of polyolefins was very low, and both the yield of aromatic hydrocarbons and the yield of BTX were very low.

[0045] The molecular sieve component used in R in Comparative Example 7 is the same as that used in catalyst A (component 1), the only difference being that it does not contain the metal Pt component. Since the molecular sieve has almost no ability to catalytically activate CO2, only olefins react in the catalytic reaction process. That is, olefins are catalyzed by the molecular sieve and directly undergo the aromatization reaction, but the yield of aromatic hydrocarbons is not high (38%), and mainly long-chain alkanes are produced, and the conversion rate of CO2 is only 0.02 g·g. (ポリオレフィン) ·h -1 Therefore, it is not possible to produce aromatic hydrocarbons with very low and high selectivity while simultaneously reducing CO2 emissions.

[0046] Comparative Examples 6 and 7 show that when only one functional component, either a metal oxide or a molecular sieve, is present, the reaction effect is poor and the excellent reaction performance described in the present invention is completely absent.

[0047] Both the catalyst used in Comparative Example 8 and the catalyst used in Example 1 are catalyst A, but no olefin was added in Comparative Example 8. The experimental results show that when polyolefin is not added, CO2 is not effectively converted.

[0048] Both the catalyst used in Comparative Example 9 and the catalyst used in Example 1 are catalyst A, but in Comparative Example 9, CO2 was not added, and N2 was used as the pressurized atmosphere gas. The experimental results showed that when CO2 is not introduced, polyolefins can be converted to aromatic hydrocarbons by a dual-function catalyst consisting of a metal and a molecular sieve, and the reaction results were similar to those of Comparative Example 7, with a relatively low yield of aromatic hydrocarbons, only 36%, indicating that it does not possess the excellent reaction performance described in the present invention.

[0049] The reaction results in Comparative Examples 8 and 9 demonstrate that the conversion of CO2 and the conversion of polyolefins are mutually coupled and supportive. In the absence of polyolefins, CO2 is not effectively converted. Furthermore, in the absence of CO2, polyolefins are not highly selectively converted to aromatic hydrocarbons, and the amount of alkane byproducts increases.

[0050] The catalyst used in Comparative Example 10 was the same as catalyst A used in Example 1. However, in Comparative Example 10, the partial pressure of CO2 was low, resulting in insufficient CO2. Therefore, the effect of CO2 in promoting the selective production of aromatic hydrocarbons was small. Consequently, it is extremely important to ensure sufficient CO2 to promote the catalytic reaction.

[0051] The table above shows that the topological structure of the molecular sieve, its acidity, the supply ratio of CO2 to polyolefin waste plastics, and the compatibility between the metal or metal oxide and the molecular sieve all play extremely important roles and directly influence the selectivity of mixed aromatic hydrocarbons, the conversion rate of CO2, and the content of benzene, toluene, and xylene in the aromatic hydrocarbons.

[0052] (Note) (Note 1) Carbon dioxide and polyolefin are used as reaction raw materials, and a binary functional catalyst is used as the catalyst, wherein one functional component consists of a metal, a metal oxide, or both, and the other functional component consists of a molecular sieve. The molecular sieve is a molecular sieve having MFI, MEL, and MWW topological structures. A method for producing aromatic hydrocarbons by coupling conversion of carbon dioxide and polyolefin, characterized in that the metal or metal oxide contains one or more elements from Fe, Co, Ni, Mn, Ce, Cu, Ru, Zn, Ga, Rh, Pd, Ir, and Pt.

[0053] (Note 2) The manufacturing method according to Appendix 1, characterized in that the pressure of the carbon dioxide is 0.2 to 6 MPa, the reaction temperature is 180 to 400°C, and the mass ratio of the catalyst to the polyolefin is ≥ 1:500.

[0054] (Note 3) When the reaction is carried out in a kettle reactor, the residence time of the reactants is 0.5 to 20 hours, and when the reaction is carried out in a moving bed reactor, the gas space velocity of the reaction is 20 to 2000 mL·g. -1 ·h -1 The manufacturing method described in Appendix 2, characterized in that it is the same as described above.

[0055] (Note 4) The mass fraction of the metal or metal oxide in relation to the binary functional catalyst is 0.1 wt% to 60 wt%, and the binary functional catalyst is constructed by directly supporting the metal or metal oxide on the molecular sieve or by dispersing it on a metal oxide support and then physically mixing it with the molecular sieve, wherein the metal oxide support is Al2O3, TiO2, ZrO2, CeO2, ZnO, MoO x , MnO x The manufacturing method according to Appendix 1, characterized by including one or more of the above.

[0056] (Note 5) The manufacturing method according to Appendix 1, characterized in that the skeletal elements of the molecular sieve having the aforementioned MFI, MEL, and MWW topological structures include at least one of Si-O, Si-O-Al, Si-O-Al-P, Si-O-Al-B, and Si-O-Al-Ge, and the molecular sieve having the aforementioned MFI, MEL, and MWW topological structures is preferably at least one of MCM-22, ZSM-11, or ZSM-5.

[0057] (Note 6) The production method according to Appendix 1, characterized in that the molecular sieve having the aforementioned MFI, MEL, and MWW topological structures contains a moderate acid, and the amount of moderate acid sites is ≥0.1 mol / kg.

[0058] (Note 7) The manufacturing method according to Appendix 1, characterized in that the metal or metal oxide is compounded with the molecular sieve by immersion, deposition, gas phase deposition, or physical mixing.

[0059] (Note 8) The manufacturing method according to Appendix 1, characterized in that the binary functional catalyst is pre-reduced, the reducing atmosphere is H2 or CO, the reduction temperature is 300°C to 500°C, and the reduction time is 0.5h to 10h.

[0060] (Note 9) The manufacturing method according to Appendix 1, characterized in that the metal and metal oxide component in the dual-function catalyst exhibit an activating effect on CO2, and the molecular sieve exhibits an activating effect on polyolefins.

[0061] (Note 10) The manufacturing method according to Appendix 9, characterized in that the polyolefin includes one or more of polyethylene, polypropylene, and polybutylene, and plastic products or used waste plastics processed using the polyolefin as a raw material.

Claims

1. Carbon dioxide and polyolefin are used as reaction raw materials, and a binary functional catalyst is used as the catalyst, wherein one functional component consists of a metal, a metal oxide, or both, and the other functional component consists of a molecular sieve. The molecular sieve is a molecular sieve having MFI, MEL, and MWW topological structures. A method for producing aromatic hydrocarbons by coupling conversion of carbon dioxide and polyolefin, characterized in that the metal or metal oxide contains one or more elements from Fe, Co, Ni, Mn, Ce, Cu, Ru, Zn, Ga, Rh, Pd, Ir, and Pt.

2. The manufacturing method according to claim 1, characterized in that the pressure of the carbon dioxide is 0.2 to 6 MPa, the reaction temperature is 180 to 400°C, and the mass ratio of the catalyst to the polyolefin is ≥ 1:

500.

3. When the reaction is carried out in a kettle reactor, the residence time of the reactants is 0.5 to 20 hours, and when the reaction is carried out in a moving bed reactor, the gas space velocity of the reaction is 20 to 2000 mL·g. －１ ・h －１ The manufacturing method according to claim 2, characterized in that it is the same.

4. The mass fraction of the metal or the metal oxide with respect to the dual-functional catalyst is 0.1 wt% to 60 wt%. The dual-functional catalyst is formed by directly supporting the metal or the metal oxide on the molecular sieve or dispersing it on a metal oxide support and then physically mixing it with the molecular sieve. The metal oxide support contains one or more of Al ２ O ３ , TiO ２ , ZrO ２ , CeO ２ , ZnO, MoO ｘ , MnO ｘ . The production method according to claim 1, characterized in that it includes one or more of these.

5. The manufacturing method according to claim 1, characterized in that the skeletal elements of the molecular sieve having the MFI, MEL, and MWW topological structures include at least one of Si-O, Si-O-Al, Si-O-Al-P, Si-O-Al-B, and Si-O-Al-Ge, and the molecular sieve having the MFI, MEL, and MWW topological structures is preferably at least one of MCM-22, ZSM-11, or ZSM-5.

6. The production method according to claim 1, characterized in that the molecular sieve having the aforementioned MFI, MEL, and MWW topological structures contains a moderate acid, and the amount of moderate acid sites is ≥ 0.1 mol / kg.

7. The manufacturing method according to claim 1, characterized in that the metal or metal oxide is combined with the molecular sieve by immersion, deposition, gas phase deposition, or physical mixing.

8. The aforementioned dual-function catalyst is pre-reduced, and the reducing atmosphere is H ２ The manufacturing method according to claim 1, characterized in that CO is used, the reduction temperature is 300°C to 500°C, and the reduction time is 0.5h to 10h.

9. The metal and metal oxide component in the aforementioned dual-function catalyst are CO ２ The manufacturing method according to claim 1, characterized in that the molecular sieve exhibits an activating effect on polyolefins.

10. The manufacturing method according to claim 9, characterized in that the polyolefin includes one or more of polyethylene, polypropylene, and polybutylene, and plastic products or used waste plastics obtained by processing the polyolefin as a raw material.

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