Method for producing light olefins from waste plastics

Abstract

The present disclosure relates to a method for producing light olefins from waste plastics, comprising: a) pyrolyzing waste plastic raw materials to produce an oil-containing stream; b) reacting part or all of the oil-containing stream in the presence of a catalyst in at least one circulating fluidized bed reactor; and c) separating and recovering light olefins from the reaction products, wherein the oil-containing stream produced in step a) is fed into the reactor of step b) without a process for removing olefins and non-hydrocarbon materials.

Description

Technology Field

[0001] The present disclosure relates to a method for producing light olefins from waste plastics. Background Technology

[0002] Light olefins, such as ethylene, propylene, and C4 olefins, are widely used in the chemical industry as basic raw materials for plastic manufacturing. While light olefins are primarily produced through the thermal cracking of petroleum-derived naphtha, this method involves high-temperature reactions exceeding 850 degrees Celsius, resulting in high energy consumption and the generation of large amounts of greenhouse gases. Therefore, there is a need for energy-efficient technologies that produce light olefins using sustainable materials, such as waste plastics. Polyolefin-based plastics, such as polyethylene (PE) and polypropylene (PP), which are widely used as packaging materials, account for over 60% of global waste plastic generation due to their short service life. The widespread application of mechanical recycling for these waste plastics is currently difficult due to impurities originating from other plastics (such as polyethylene terephthalate (PET), polystyrene (PS), and polyurethane (PU)), additives, and fillers. Furthermore, disposal methods such as landfilling and incineration are unsuitable approaches as they are prone to causing environmental pollution. Therefore, to reduce the negative environmental impact of existing waste plastic disposal methods and transition to a circular economy with low carbon emissions, it is necessary to develop a new energy-efficient process that converts waste plastic into valuable light olefins.

[0003] In this context, methods for producing light olefins by utilizing pyrolysis oil generated from the pyrolysis of waste plastics as a feedstock for conventional naphtha cracking processes after hydrogenation are being actively developed (JP 6942178). In this method, waste plastics degrade in the absence of oxygen to produce gas, liquid oil, and residue. Waste plastic pyrolysis oil contains hydrocarbons ranging from C5 with various structures to polymer waxes. This composition is highly dependent on degradation conditions, such as reactor type, reaction temperature, and heating rate, as well as the type of waste plastic. The generated pyrolysis oil mainly contains olefins, paraffins, and aromatic compounds, with olefins being the main component. The generated pyrolysis oil undergoes hydrogenation to remove impurities and contaminants, after which it is converted into light olefins through conventional naphtha pyrolysis processes. However, waste plastic-derived pyrolysis oil has characteristics different from petroleum-derived naphtha, making it difficult to use directly as a feedstock for naphtha pyrolysis processes.

[0004] First, there is a problem regarding the hydrocarbon composition in the pyrolysis oil. The carbon number of waste plastic pyrolysis oil generally consists of a wide range from C5 to C24, whereas naphtha consists of carbon numbers from C5 to C9. Therefore, the fraction that can be processed in the existing naphtha cracking process is less than 40% of the pyrolysis oil.

[0005] Second, approximately 30–50% of olefins are generated in the pyrolysis oil during the pyrolysis of waste plastics. Since high olefin content causes coke formation during the cracking reaction, industrial companies limit the olefin content in naphtha to a maximum of 1–2 weight%. To address this, it is essential to remove olefins through a hydrogenation reaction before feeding the pyrolysis oil into the naphtha cracking process.

[0006] Third, pyrolysis oil derived from waste plastics contains a large number or amount of heteroatom compounds (N, S, halogens, O, P, etc.) and metals (Al, Sb, Ba, Ca, Cr, Cu, Fe, K, Na, Pb, Si, Ti, Zn, As, Hg, Ni, V, etc.) that are not present in conventional naphtha or have relatively low content. In particular, chlorine compounds generated by PVC or salt in waste plastics require thorough management because they can cause sudden accidents due to stress corrosion cracking within the facility. To address this, a process of removing impurities through a hydrogenation reaction is essential before feeding the pyrolysis oil into the naphtha cracking process.

[0007] However, this process of removing olefins and impurities through hydrogenation requires the installation of a separate reactor and consumes large quantities of expensive hydrogen, which can negatively impact economic feasibility. Therefore, there is a need for a new method to produce light olefins from waste plastics using low energy, without the use of hydrogen, and by utilizing the entire waste plastic pyrolysis oil.

[0008] Catalytic cracking reactions are a promising alternative capable of overcoming the existing problems associated with waste plastic pyrolysis oil compared to conventional non-catalytic pyrolysis reactions. Catalytic cracking reactions can utilize waste plastic pyrolysis oil composed of a wide range of carbon numbers containing large amounts of olefins as a raw material, enabling the production of high-yield light olefins with relatively low energy consumption. However, the coke generated during this process causes rapid catalyst deactivation, which limits the continuous use of the catalyst. Therefore, a reactor equipped with a continuous catalyst regeneration system, such as a circulating fluidized bed reactor, is required. Furthermore, zeolite-based catalysts, particularly ZSM-5, are known to be excellent for pyrolysis oil cracking. However, to selectively produce high-yield light olefins, controlling the catalyst's acid sites and ensuring hydrothermal stability are essential. Moreover, securing optimal operating conditions (reaction temperature, space velocity, etc.) is also necessary. The problem to be solved

[0009] The present disclosure aims to provide a method for producing light olefins from waste plastics that is environmentally friendly by reducing greenhouse gas emissions through the production of light olefins from waste plastics, utilizes the entire oil-containing stream generated by the pyrolysis of waste plastic raw materials, enables process simplification by eliminating a separate removal process for olefin or non-hydrocarbon materials contained in the oil-containing stream, and significantly improves the yield of light olefins, thereby enhancing process economics. means of solving the problem

[0010] The present disclosure may provide a method for producing light olefins from waste plastics, comprising: a) pyrolyzing waste plastic raw materials to produce an oil-containing stream; b) reacting part or all of the oil-containing stream in the presence of a catalyst in at least one circulating fluidized bed reactor; and c) separating and recovering light olefins from the reaction products, wherein the oil-containing stream produced in step a) is fed into the reactor of step b) without a process for removing olefins and non-hydrocarbon materials.

[0011] In one embodiment according to the present disclosure, the oil-containing stream may comprise 20 to 60 weight% of olefins, 5 to 30 weight% of aromatic hydrocarbons, and 15 to 40 weight% of hydrocarbons in the naphtha region.

[0012] In one embodiment according to the present disclosure, the oil-containing stream may contain 100 to 7000 ppm of nitrogen, 10 to 3000 ppm of sulfur, and 1 to 5000 ppm of halogen.

[0013] In one embodiment according to the present disclosure, a method for producing a light olefin from the waste plastic may further include the step of contacting the oil-containing stream with any one of an adsorbent selected from activated carbon, ion exchange resin, silica gel, clay, zeolite, molecular sieve, activated aluminum oxide, and layered double hydroxide.

[0014] In another embodiment of the present disclosure, the catalyst may be one in which phosphorus (P) has been introduced.

[0015] In one embodiment according to the present disclosure, the catalyst may be pre-steamed.

[0016] In one embodiment according to the present disclosure, the catalyst may be a spherical or elliptical molded body with a diameter of 30 μm to 200 μm.

[0017] In one embodiment according to the present disclosure, the catalyst may be synthesized by adding a zeolite seed.

[0018] In one embodiment according to the present disclosure, step b) may be performed in a circulating fluidized bed reactor comprising a reactor, a stripper, and a regenerator.

[0019] In one embodiment according to the present disclosure, the light olefin may be ethylene, propylene, or a C4 olefin.

[0020] In one embodiment according to the present disclosure, the sum of the light olefin yields may be 40 to 70 weight percent with respect to 100 weight percent of the oil-containing stream.

[0021] In one embodiment according to the present disclosure, the reaction may be carried out at a reaction temperature of 590 to 720 ℃.

[0022] In one embodiment according to the present disclosure, the reaction is at a space velocity (WHSV, Weight Hourly Space Velocity) of 4 h, defined as the ratio of the mass flow rate of the oil-containing stream to the mass of the catalyst. -1 to 24 h -1 It may be performed as.

[0023] In one embodiment according to the present disclosure, the catalyst may comprise a zeolite.

[0024] In one embodiment according to the present disclosure, the zeolite may comprise at least one selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-48, zeolite X, zeolite Y, zeolite-L, zeolite-β, zeolite-Ω, mordenite, erionite, chabazite, and MFI zeolite. Effects of the invention

[0025] The method for producing light olefins from waste plastics according to the present disclosure is environmentally friendly by reducing greenhouse gas emissions and can utilize the entire oil-containing stream generated by the pyrolysis of waste plastic raw materials. Furthermore, since there is no separate process for removing olefin or non-hydrocarbon materials contained in the oil-containing stream, process simplification is possible, and it is possible to establish a process with improved economic efficiency by significantly increasing the yield of light olefins.

[0026] In particular, the method for producing light olefins from waste plastics according to the present disclosure can prevent catalyst deactivation by steam at high temperatures during catalyst regeneration by carrying out the reaction in the presence of a catalyst to which phosphorus (P) has been introduced, and can achieve a significantly superior light olefin yield by using a catalyst to which phosphorus (P) has been introduced after pre-steaming treatment. In addition, a significantly superior light olefin yield can be achieved by using a pre-steamed catalyst to which phosphorus (P) has been introduced by utilizing a zeolite seed. Brief explanation of the drawing

[0027] Figure 1 is an SEM image of a catalyst prepared according to Preparation Example 3 below. FIG. 2 is a schematic diagram showing an example of a circulating fluidized bed reactor according to the present disclosure. Specific details for implementing the invention

[0028] Hereinafter, a method for producing light olefins from waste plastics according to the present disclosure is described in detail.

[0029] Unless otherwise defined, technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the disclosure are omitted in the following description.

[0030] Additionally, the singular form used in this specification may be intended to include the plural form unless specifically indicated otherwise in the context.

[0031] Additionally, units used herein without special reference are based on weight, and, for example, units of % or ratio mean weight % or weight ratio, and weight % means the weight percentage of any one component of the total waste mixture within the waste mixture unless otherwise defined.

[0032] Additionally, numerical ranges used herein include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in the specification of this disclosure, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0033] The term "comprising" in this specification is an open description having an equivalent meaning to expressions such as "comprising," "containing," "having," or "characterizing," and does not exclude elements, materials, or processes not additionally listed.

[0034] The term 'Weight Hourly Space Velocity (WHSV)' in this specification is defined as the ratio of the mass flow rate of an oil-containing stream to the mass of a catalyst.

[0035] Hereinafter, a method for producing light olefins from waste plastics according to the present disclosure is described in detail.

[0036] The present disclosure provides a method for producing light olefins from waste plastics, comprising: a) pyrolyzing waste plastic raw materials to produce an oil-containing stream; b) reacting part or all of the oil-containing stream in the presence of a catalyst in at least one circulating fluidized bed reactor; and c) separating and recovering light olefins from the reaction products, wherein the oil-containing stream produced in step a) is fed into the reactor of step b) without a process for removing olefins and non-hydrocarbon materials.

[0037] The method for producing light olefins from waste plastics according to the present disclosure is environmentally friendly by reducing greenhouse gas emissions through the production of light olefins from waste plastics, and allows for the utilization of the entire oil-containing stream generated by the pyrolysis of waste plastic raw materials. Furthermore, since there is no separate process for removing olefin or non-hydrocarbon substances contained in the oil-containing stream, process simplification is possible, and the yield of light olefins is significantly improved, thereby enhancing process economics.

[0038] In particular, the method for producing light olefins from waste plastics according to the present disclosure enables the process to be configured without a process for removing olefins or non-hydrocarbon substances, even if the oil-containing stream generated by the pyrolysis of waste plastic raw materials contains olefins or non-hydrocarbon substances such as nitrogen, sulfur, oxygen, and halogen components. Therefore, there is an advantage in that the process can be simplified and a process with improved economic efficiency can be established.

[0039] Step a) above is a step of pyrolyzing waste plastic raw materials, which is a process of converting waste plastic into an oil-containing stream containing hydrocarbon products within a pyrolysis unit.

[0040] The above waste plastics may specifically include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), etc., but are not limited thereto.

[0041] The above oil-containing stream is produced by pyrolyzing waste plastic raw materials, and may further be mixed with biomass pyrolysis oil, recycled lubricating oil, high-chlorine content crude oil, Fischer-Trropsch process products, or mixtures thereof as needed.

[0042] Step a) above may use a pyrolysis method using a batch reactor, for example, a rotary quilline type batch reactor, and may proceed with pyrolysis after uniformly melting the waste plastic, but is not limited thereto.

[0043] The above step a) may include, but is not limited to, a pretreatment step for purposes such as removing impurities and an additive injection step.

[0044] In one embodiment, the method may further include the step of filtering the oil-containing stream through a filter.

[0045] In one embodiment, the method may further include the step of contacting the oil-containing stream with any one of an adsorbent selected from activated carbon, ion exchange resin, silica gel, clay, zeolite, molecular sieve, activated aluminum oxide, and layered double hydroxide.

[0046] The above method further includes the step of contacting the oil-containing stream with an adsorbent selected from activated carbon, ion exchange resin, silica gel, clay, zeolite, molecular sieve, activated aluminum oxide, and layered double hydroxide, thereby removing solid components contained in the oil-containing stream or substances that can be easily converted into coke in the reactor before being introduced into the reactor of step b), thereby ensuring stable process operation and achieving the desired process yield.

[0047] Step a) above may be performed at a temperature of 700°C or lower, 200 to 600°C, 350 to 500°C, or 400 to 500°C. Additionally, Step a) above may be performed at a pressure of 0 to 3 bar,g or 0 to 0.3 bar,g, but is not limited thereto.

[0048] Step a) above may involve pyrolysis for 30 minutes to 16 hours, preferably for 3 hours to 10 hours, but is not limited thereto.

[0049] In one embodiment, the oil-containing stream may contain 1 to 80 weight%, 10 to 70 weight%, or 20 to 60 weight% of olefin.

[0050] In one embodiment, the oil-containing stream may contain 1 weight% or more, 2 weight% or more, 3 weight% or more, or 4 weight% or more and 5 weight% or more of aromatic hydrocarbons. Additionally, the oil-containing stream may contain 50 weight% or less, 45 weight% or less, 40 weight% or less, 35 weight% or less, or 30 weight% or less of aromatic hydrocarbons. The oil-containing stream may contain 1 to 50 weight%, 3 to 40 weight%, or 5 to 30 weight% of aromatic hydrocarbons.

[0051] In one embodiment, the oil-containing stream may contain hydrocarbons in the naphtha region composed of C5-C9 hydrocarbons in an amount of 1 wt% or more, 3 wt% or more, 5 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, or 10 wt% or more. Additionally, the oil-containing stream may contain naphtha containing C2-C12 hydrocarbons in an amount of 50 wt% or less, 45 wt% or less, or 40 wt% or less. The oil-containing stream may contain hydrocarbons in the naphtha region composed of C5-C9 hydrocarbons in an amount of 1 to 50 wt%, 10 to 45 wt%, or 15 to 40 wt%.

[0052] In one embodiment, the oil-containing stream may simultaneously contain 20 to 60 weight% of olefins, 5 to 30 weight% of aromatic hydrocarbons, and 15 to 40 weight% of hydrocarbons in the naphtha region composed of C5-C9 hydrocarbons.

[0053] The above non-hydrocarbon material may include at least one material selected from the group consisting of nitrogen component materials, sulfur component materials, oxygen component materials, and halogen component materials, but is not limited thereto.

[0054] In one embodiment, the oil-containing stream may contain 100 to 7000 ppm of nitrogen components.

[0055] In one embodiment, the oil-containing stream may contain 10 to 3000 ppm of sulfur.

[0056] In one embodiment, the oil-containing stream may contain 0.01 to 4 weight percent of an oxygen component.

[0057] In one embodiment, the oil-containing stream may contain 1 to 5000 ppm of halogen components.

[0058] In one embodiment, the oil-containing stream may simultaneously contain 100 to 7000 ppm of nitrogen, 10 to 3000 ppm of sulfur, 0.01 to 4 weight% of oxygen, and 1 to 5000 ppm of halogen.

[0059] Step b) above is a step of catalytic cracking the oil-containing stream, which is a process of converting the oil-containing stream into light olefins within a reactor.

[0060] In one embodiment, step b) may be performed in the presence of a catalyst in at least one circulating fluidized bed reactor, but is not limited thereto.

[0061] In one embodiment, step b) may be performed in a circulating fluidized bed reactor comprising a reactor, a stripper, and a regenerator, but is not limited thereto.

[0062] When step b) above is performed in a circulating fluidized bed reactor, the method for producing light olefins from waste plastics according to the present disclosure utilizes the entire oil-containing stream generated by the pyrolysis of waste plastic raw materials, and simplifies the process by eliminating the removal of olefins or non-hydrocarbon substances contained in the oil-containing stream. Furthermore, due to the structural characteristics of the circulating fluidized bed reactor, the residence time of the reaction product within the reactor is short, which significantly improves the yield of light olefins, and it is possible to construct a process with significantly improved economic efficiency by continuously removing coke from the catalyst.

[0063] In one embodiment, the reactor may be one in which steam is injected as a moving gas along with an oil-containing stream generated by pyrolyzing waste plastic raw materials into the reactor.

[0064] In step b) above, the reaction may be performed at 900°C or lower, 800°C or lower, 750°C or lower, 720°C or lower, 700°C or lower, or 680°C or lower. Additionally, in step b), the reaction may be performed at 300°C or higher, 400°C or higher, 450°C or higher, 500°C or higher, 540°C or higher, 550°C or higher, 570°C or higher, 580°C or higher, 590°C or higher, 600°C or higher, 620°C or higher, 640°C or higher, or 650°C or higher. Step b) above may be performed at 500 to 800°C, 520 to 750°C, or 590 to 720°C.

[0065] If the reaction temperature is below 590°C, the oil-containing stream produced by pyrolyzing waste plastic raw materials is not sufficiently converted into light olefins, and if it exceeds 720°C, the light olefins produced are converted into aromatic hydrocarbons due to the influence of excessive secondary reactions, which may result in a problem of reduced light olefin yield.

[0066] The above reaction is performed at a space velocity (WHSV, Weight Hourly Space Velocity) of 1 to 100 h, defined as the ratio of the mass flow rate of the oil-containing stream to the mass of the catalyst. -1 , 1 to 80 h -1 , 1 to 70 h -1 , 1 to 60 h -1 , 2 to 60 h -1 , 2 to 50 h -1 3 to 50 h -1 , 4 to 48 h -1 , 6 to 24 h -1 or 6 to 10 h -1 It can be performed as.

[0067] The spatial velocity is 24 h -1 In the case of excess, the oil-containing stream generated by the pyrolysis of waste plastic raw materials is not sufficiently converted into light olefins, and 6 h -1 If it is less than that, the light olefins produced are converted into aromatic hydrocarbons due to the influence of excessive secondary reactions, which may result in a problem of reduced light olefin yield.

[0068] As the catalyst, zeolite, clay, SAPO (silica-alumina-phosphate), ALPO (aluminum phosphate), MOF (Metal Organic Framework), amorphous silica-alumina, or a mixture thereof may be used. In addition, waste zeolite, waste clay, etc. can be utilized as is or after undergoing simple treatment to further improve activity. To use the waste zeolite, waste clay, etc. as a catalyst, air combustion may be carried out to remove coke, or solvent treatment may be performed to remove oil.

[0069] The above zeolite may include at least one selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-48, zeolite X, zeolite Y, zeolite-L, zeolite-β, zeolite-Ω, mordenite, erionite, chabazite, and MFI zeolite.

[0070] The catalyst may further include a carrier or binder comprising carbon, alkaline earth metal oxide, alkali metal oxide, alumina, silica, silica-alumina, zirconia, titania, silicon carbide, niobia, aluminum phosphate, alumina hydrate, or a mixture thereof.

[0071] In one embodiment, the catalyst may have phosphorus (P) introduced into it.

[0072] The method for producing light olefins from waste plastics according to the present disclosure can maintain an excellent yield of light olefins by preventing catalyst deactivation by steam during the catalytic reaction or regeneration process in the presence of the catalyst in which phosphorus (P) is introduced.

[0073] In one embodiment, the catalyst may be pre-steamed.

[0074] The method for producing light olefins from waste plastics according to the present disclosure can achieve a significantly superior yield of light olefins by using a catalyst to which phosphorus (P) has been introduced and pre-steamed. That is, compared to the case where a catalyst is used without pre-steaming treatment, the catalyst used after pre-steaming treatment exhibits the effect of showing a significantly superior yield of light olefins.

[0075] In one embodiment, the catalyst may be a spherical or elliptical molded body.

[0076] In addition, in one embodiment, the catalyst may have a diameter of 1 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, 60 μm or more, or 70 μm or more. In addition, the catalyst may have a diameter of 500 μm or less, 400 μm or less, 300 μm or less, 250 μm or less, 200 μm or less, or 150 μm or less. The catalyst may have a diameter of 30 μm to 200 μm or 50 μm to 150 μm.

[0077] If the catalyst diameter is less than 50 μm, the oil-containing stream produced by the pyrolysis of waste plastic raw materials may not be sufficiently converted into light olefins due to the short residence time in the reactor, or it may be difficult to separate the catalyst and the product after the reaction. If the diameter is greater than 150 μm, the flow of the catalyst in the reactor may not be smooth, or problems such as catalyst wear may occur during flow.

[0078] In one embodiment, the catalyst may be synthesized by adding a zeolite seed. When the catalyst is synthesized by adding a zeolite seed, a significantly superior yield of light olefin can be achieved compared to when it is synthesized without adding a zeolite seed.

[0079] In one embodiment, the light olefin may include ethylene, propylene, or C4 olefin.

[0080] In one embodiment, the light olefin yield may be 40 wt% or more, 42 wt% or more, 44 wt% or more, 46 wt% or more, 48 wt% or more, 50 wt% or more, 52 wt% or more, 54 wt% or more, or 56 wt% or more, with respect to 100 wt% of the oil-containing stream of step a). Additionally, the sum of the light olefin yields may be 75 wt% or less, 70 wt% or less, 65 wt% or less, or 60 wt% or less. The sum of the light olefin yields may be 44 to 60 wt%, 40 to 70 wt%, or 44 to 70 wt% with respect to 100 wt% of the oil-containing stream.

[0081] The present disclosure is explained in more detail below based on examples and comparative examples. However, the following examples and comparative examples are merely illustrative of the present disclosure and are not limited by the following examples and comparative examples. Unless otherwise stated in the invention, all temperatures refer to units of °C, and unless otherwise stated, the amount of the composition used refers to units of weight %.

[0082] [Experimental Example 1]

[0083] Phase analysis of the catalyst product was performed by collecting 2θ 7–9° and 22–25° data corresponding to the characteristic peaks of ZSM-5 using an X-ray diffraction analyzer (e.g., Rigaku Model D / Max III).

[0084] [Preparation Example 1 - ZSM-5 Synthesis]

[0085] Solution 1 was prepared by adding 29.51 g of distilled water to 36.83 g of water glass and stirring for 30 minutes. Additionally, Solution 2 was prepared by mixing 3.95 g of aluminum sulfate, 0.19 g of sulfuric acid, and 29.51 g of distilled water and stirring for 20 minutes. Next, Solution 2 was added to Solution 1 and stirred, then placed in a Teflon container and hydrothermally synthesized at 170°C for 24 hours, followed by cooling at room temperature. After cooling, 4 g of ZSM-5 zeolite recovered through filtration and washing was mixed with 50 g of a 10 wt% ammonium sulfate solution and stirred for 30 minutes. Ion exchange was then performed by repeating the washing and filtration process three times in succession to produce ZSM-5.

[0086] Phase analysis of the product obtained according to the above method can be performed by collecting 2θ 7–9° and 22–25° data corresponding to the characteristic peaks of ZSM-5 using an X-ray diffraction analyzer (e.g., Rigaku Model D / Max III). From the analyzed X-ray diffraction pattern, it was confirmed that the prepared zeolite has a ZSM-5 crystal structure.

[0087] [Preparation Example 2 - Preparation of ZSM-5 Molded Catalyst]

[0088] A slurry was prepared by slowly adding 165.25 g of ZSM-5 (Si / Al = 11) synthesized in Preparation Example 1 to 321.23 g of distilled water while stirring. To the slurry, a solution in which 277.54 g of boehmite (Al2O3 content 72 wt%) was dispersed in a 2% nitric acid solution was additionally added and stirred for 1 hour. Then, 227 g of clay was added and thoroughly mixed for 2 hours using a high-viscosity slurry mixer. The slurry was spray-molded to obtain microspheres with a particle size of 75-200 μm, and calcined at 650°C for 5 hours. After calcination, a ZSM-5 molded catalyst was obtained.

[0089] [Preparation Example 3 - Preparation of P / ZSM-5 Molded Catalyst]

[0090] A slurry was prepared by slowly adding 165.25 g of ZSM-5 (Si / Al = 11) synthesized in Preparation Example 1 to 321.23 g of distilled water while stirring. Then, 71.47 g of 85% phosphoric acid was added, and the mixture was stirred at room temperature for 30 minutes. To the slurry, a solution of 277.54 g of boehmite (Al2O3 content 72 wt%) dispersed in a 2% nitric acid solution was added and stirred for 1 hour. Subsequently, 166.5 g of clay was added and thoroughly mixed for 2 hours using a high-viscosity slurry mixer. The slurry was spray-molded to obtain microspheres with a particle size of 75-200 μm, and calcined at 650°C for 5 hours. After calcination, a P / ZSM-5 molded catalyst was obtained.

[0091] [Preparation Example 4 - Preparation of Pre-steamed ZSM-5 Molded Catalyst]

[0092] After loading the ZSM-5 molded catalyst obtained in Preparation Example 2 into a steam treatment reactor, distilled water was injected at a rate of 5 cc / min using a liquid pump and vaporized into steam form, which was then brought into contact with a sample in a 100% steam atmosphere at 760°C for 24 hours to obtain a pre-steamed ZSM-5 molded catalyst.

[0093] [Preparation Example 5 - Preparation of Pre-steamed P / ZSM-5 Molding Catalyst]

[0094] After loading the P / ZSM-5 molded catalyst obtained in Preparation Example 3 into a steam treatment reactor, distilled water was injected at a rate of 5 cc / min using a liquid pump and vaporized into steam form, which was then brought into contact with a sample in a 100% steam atmosphere at 760°C for 24 hours to obtain a pre-steamed P / ZSM-5 molded catalyst.

[0095] [Preparation Example 6 - Synthesis of ZSM-5 using ZSM-5 seed]

[0096] 0.1 g of aluminum isopropoxide, an alumina source, was added to 31.53 g of TPAOH, an organic structure-directing agent, and stirred for 30 minutes to prepare a homogeneous liquid. Then, 52.602 g of TEOS and 15.73 g of distilled water were added and stirred for 2 hours. The above reaction mixture was placed in a microwave synthesis reactor (CEM Corporation), and microwaves were irradiated in two stages: Stage 1 at 80°C for 90 minutes and Stage 2 at 130°C for 180 minutes to synthesize nanocrystalline ZSM-5 nuclei. After the synthesis was completed, ZSM-5 seeds were obtained from the mother liquor by centrifugation.

[0097] Solution 1 was prepared by adding 29.51 g of distilled water to 0.5 g of obtained ZSM-5 seeds with an average size of 100 nm and 36.83 g of water glass, and stirring for 30 minutes. Solution 2 was prepared by mixing 3.95 g of aluminum sulfate, 0.19 g of sulfuric acid, and 29.51 g of distilled water and stirring for 20 minutes. Then, Solution 2 was added to Solution 1 and stirred, placed in a Teflon container, hydrothermally synthesized at 170°C for 24 hours, and then cooled to room temperature. After cooling, 5 g of ZSM-5 zeolite recovered through filtration and washing was mixed with 50 g of a 10 wt% ammonium sulfate solution, stirred for 30 minutes, and then ion exchange was performed by repeating the washing and filtration process three times in succession to prepare ZSM-5 using the ZSM-5 seeds.

[0098] [Preparation Example 7 - Preparation of P / ZSM-5 molded catalyst using ZSM-5 seed]

[0099] A slurry was prepared by slowly adding 165.25 g of ZSM-5 (Si / Al = 11) using the ZSM-5 seed synthesized in Preparation Example 6 to 321.23 g of distilled water while stirring. Then, 71.47 g of 85% phosphoric acid was added, and the mixture was stirred at room temperature for 30 minutes. To the slurry, a solution of 277.54 g of boehmite (Al2O3 content 72 wt%) dispersed in a 2% nitric acid solution was added and stirred for 1 hour. Subsequently, 166.5 g of clay was added and thoroughly mixed for 2 hours using a high-viscosity slurry mixer. The slurry was spray-molded to obtain microspheres with a particle size of 75-200 μm, and calcined at 650°C for 5 hours. After calcination, a P / ZSM-5 molded catalyst using the ZSM-5 seed was obtained.

[0100] [Preparation Example 8 - Preparation of P / ZSM-5 molded catalyst using pre-steamed ZSM-5 seeds]

[0101] After loading the P / ZSM-5 molded catalyst using the ZSM-5 seed obtained in Preparation Example 7 into a steam treatment reactor, distilled water was injected at a rate of 5 cc / min using a liquid pump and vaporized into a steam form, which was then brought into contact with a sample in a 100% steam atmosphere at 760°C for 24 hours to obtain a P / ZSM-5 molded catalyst using a pre-steamed ZSM-5 seed.

[0102] [Example 1]

[0103] a) Waste mixed plastics (PE, PP, and PS) were fed into a rotary quilline reactor and pyrolyzed in an oxygen-free atmosphere to produce an oil-containing stream. Fuel was supplied to the bottom of the rotating reactor and combusted to heat the internal temperature of the reactor to 350 to 500°C. At this time, the gas emitted from the pyrolysis was condensed to produce an oil-containing stream with a density of 0.812 g / cm³ and a viscosity of 4.0 cP at 23.6°C.

[0104] b) The above oil-containing stream was fed into a simulated fluidized bed reactor loaded with 3g of catalyst, and catalyst cracking was carried out. (Feed rate 0.8 g / min, reaction temperature 680 ℃, space velocity (WHSV) 16 h -1 , reaction time 90 seconds)

[0105] At this time, the catalyst used was the catalyst prepared according to Preparation Example 3 above.

[0106] c) The light olefins were separated from the above reaction products through a conventional fractional distillation method and each was recovered. The recovered ethylene yield, propylene yield, C4 olefin yield, and light olefin yield sum, calculated based on 100 wt% of the input oil-containing stream, are shown in Table 1.

[0107] [Comparative Example 1]

[0108] The procedure was carried out in the same manner as Example 1, except that thermal decomposition was performed without using a catalyst in the reactor.

[0109] [Example 2]

[0110] The procedure was carried out in the same manner as Example 1, except that the catalyst prepared according to Preparation Example 4 was used as the catalyst.

[0111] [Example 3]

[0112] The procedure was carried out in the same manner as Example 1, except that the catalyst prepared according to Preparation Example 5 was used as the catalyst.

[0113] [Comparative Example 2]

[0114] The experiment was carried out in the same manner as Example 1, except that oil-containing streams derived from waste plastic pyrolysis oil were not used as reactants for the catalyst evaluation, and naphtha derived from petroleum was used instead.

[0115] Ethylene yield (weight%) Propylene yield (weight%) C4 Olefin Yield (Weight%) Total light olefin yield (weight%) Example 1 19.7 23.9 10.4 54.0 Comparative Example 1 13.6 14.1 8.3 36.0 Example 2 14.9 24.3 15.7 54.9 Example 3 18.7 26.3 11.5 56.5 Comparative Example 2 10.3 16.7 8.2 36.2

[0116] As can be seen in Table 1 above, when compared to the case of thermal decomposition without using a catalyst as in Comparative Example 1, when using a catalyst with phosphorus (P) introduced as in Example 1 (Preparation Example 3), an excellent sum of light olefin yields can be achieved.

[0117] As can be seen in Table 1 above, when a catalyst without phosphorus (P) is used after pre-steaming treatment as in Example 2 (Preparation Example 4), a superior sum of light olefin yields can be achieved compared to when a catalyst with phosphorus (P) is used as in Example 1 (Preparation Example 3).

[0118] As can be seen in Table 1 above, when a catalyst with phosphorus (P) introduced as in Example 3 is used after pre-steaming treatment (Preparation Example 5), a higher sum of light olefin yields can be achieved than when a catalyst with phosphorus (P) introduced in Example 1 is used without pre-steaming treatment (Preparation Example 3).

[0119] Table 1 above can be seen that in a catalyst with phosphorus (P) introduced without prior steaming treatment (Preparation Example 3), when using a waste plastic-derived oil stream as in Example 1 compared to when using naphtha as a raw material as in Comparative Example 2, an excellent sum of light olefin yields can be achieved.

[0120] [Example 4-1]

[0121] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 540 ℃.

[0122] [Example 4-2]

[0123] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 570 ℃.

[0124] [Example 4-3]

[0125] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 590 ℃.

[0126] [Example 4-4]

[0127] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 610 ℃.

[0128] [Examples 4-5]

[0129] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 630 ℃.

[0130] [Examples 4-6]

[0131] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 650 ℃.

[0132] [Examples 4-7]

[0133] The procedure was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 700 ℃.

[0134] [Examples 4-8]

[0135] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 720 ℃.

[0136] [Examples 4-9]

[0137] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction temperature was 750 ℃.

[0138] Reaction temperature (°C) Ethylene yield (weight%) Propylene yield (weight%) C4 Olefin Yield (Weight%) Total light olefin yield (weight%) Example 4-1 540 3.3 15.6 14.2 33.2 Example 4-2 570 5.1 19.7 16.5 41.3 Example 4-3 590 7.9 23.1 17.0 48.0 Examples 4-4 610 11.4 25.5 16.0 52.9 Examples 4-5 630 12.6 25.8 14.9 53.3 Examples 4-6 650 16.7 26.4 13.0 56.1 Example 3 680 18.8 26.3 11.6 56.6 Examples 4-7 700 20.4 25.6 8.4 54.3 Examples 4-8 720 23.9 24.2 6.2 54.3 Examples 4-9 750 25.1 17.6 1.6 44.3

[0139] As can be seen in Table 2 above, excellent light olefin yields can be achieved in the reaction temperature range of 590 °C to 720 °C, as in Examples 3 and 4-3 to 4-8. Additionally, it can be seen that the best light olefin yields are achieved at reaction temperatures of 650 to 680 °C.

[0140] [Example 5-1]

[0141] By adjusting the amount of catalyst, the catalyst space velocity (WHSV) is 24 h -1Except for the fact that it was carried out in the same way as Example 3, it was carried out.

[0142] [Example 5-2]

[0143] By adjusting the amount of catalyst, the catalyst space velocity (WHSV) is 12 h -1 Except for the fact that it was carried out in the same way as Example 3, it was carried out.

[0144] [Example 5-3]

[0145] By adjusting the amount of catalyst, the catalyst space velocity (WHSV) is 8 h -1 Except for the fact that it was carried out in the same way as Example 3, it was carried out.

[0146] [Example 5-4]

[0147] By adjusting the amount of catalyst, the catalyst space velocity (WHSV) is 4 h -1 Except for the fact that it was carried out in the same way as Example 3, it was carried out.

[0148] Space velocity (h -1 ) C2 = Yield (weight%) C3 = Yield (weight%) C4 = Yield (weight%) Total olefin yield (weight%) Example 5-1 24 15.5 21.7 11.5 48.7 Example 3 16 18.8 26.3 11.6 56.6 Example 5-2 12 18.5 26.6 12.0 57.1 Example 5-3 8 20.0 28.0 12.4 60.4 Examples 5-4 4 20.4 26.2 10.8 57.3

[0149] 4 h as in Examples 3 and 5-1 to 5-4 -1 at 24 h -1 It can be confirmed from Table 3 above that excellent light olefin yields can be achieved in the space velocity region. In particular, 4 h -1 at 16 h -1 It can be seen that the best light olefin yield can be achieved in the space velocity region.

[0150] [Example 6-1]

[0151] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction time was 270 seconds.

[0152] [Example 6-2]

[0153] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction time was 450 seconds.

[0154] [Example 6-3]

[0155] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction time was 630 seconds.

[0156] [Example 6-4]

[0157] The experiment was carried out in the same manner as Example 3, except that the catalyst cracking reaction time was 810 seconds.

[0158] [Example 6-5]

[0159] After regenerating the deactivated catalyst at 730°C for 8 hours in an air atmosphere following the 810-second reaction, the reaction was repeated under the same conditions as in Example 3.

[0160] Reaction time (seconds) C2 = Yield (weight%) C3 = Yield (weight%) C4 = Yield (weight%) Total olefin yield (weight%) Example 3 90 18.7 26.3 11.5 56.5 Example 6-1 270 15.8 25.0 13.4 54.2 Example 6-2 450 15.3 24.4 13.6 53.3 Example 6-3 630 15.2 24.4 14.0 53.6 Examples 6-4 810 14.7 23.7 14.1 52.5 Examples 6-5 After playback 18.8 26.2 12.0 57.0

[0161] As shown in Examples 3 and 6-1 to 6-5, it was confirmed that the catalyst activity decreased rapidly with reaction time, and as shown in Table 4 above, the initial catalyst activity can be recovered after regeneration. From this, it can be seen that the catalyst is not suitable for use in fixed-bed reactors due to rapid deactivation caused by coke deposition, but is suitable for fluidized-bed reactors that include a regeneration section, particularly circulating fluidized-bed reactors.

[0162] [Example 7]

[0163] The procedure was carried out in the same manner as Example 1, except that the catalyst prepared according to Preparation Example 8 was used as the catalyst.

[0164] catalyst C2 = Yield (weight%) C3 = Yield (weight%) C4 = Yield (weight%) Total olefin yield (weight%) Example 7 18.6 26.5 12.6 57.7 Example 3 18.7 26.3 11.5 56.5

[0165] As can be seen in Table 5 above, when compared to Example 3, the best olefin yield can be achieved when the catalyst prepared using a seed as in Example 7 is used after pre-steaming treatment (Preparation Example 8).

[0166] Although preferred embodiments of the present disclosure have been described above, it is clear that the present disclosure may be used with various variations and equivalent scopes, and that the above embodiments may be applied in the same way by appropriately modifying them. Accordingly, the above description does not limit the scope of the present disclosure as defined by the following claims.

Claims

Claim 1 a) a step of pyrolyzing waste plastic raw materials to produce an oil-containing stream; b) a step of reacting part or all of the oil-containing stream in the presence of a catalyst in a circulating fluidized bed reactor comprising at least one reactor, stripper, and regenerator; c) a step of separating and recovering light olefins from the product of the reaction step; wherein the oil-containing stream produced in step a) is fed into the reactor of step b) without a process of removing olefins and non-hydrocarbon materials. A method for producing light olefins from waste plastics. Claim 2 A method for producing light olefin from waste plastic according to claim 1, wherein the oil-containing stream comprises 20 to 60 weight% olefin, 5 to 30 weight% aromatic hydrocarbon, and 15 to 40 weight% hydrocarbon of the naphtha region. Claim 3 A method for producing light olefins from waste plastics according to claim 1, wherein the oil-containing stream comprises 100 to 7000 ppm of nitrogen components, 10 to 3000 ppm of sulfur components, and 1 to 5000 ppm of halogen components. Claim 4 A method for producing light olefins from waste plastics according to claim 1, further comprising the step of contacting the oil-containing stream with any one of an adsorbent selected from activated carbon, ion exchange resin, silica gel, clay, zeolite, molecular sieve, activated aluminum oxide, and layered double hydroxide. Claim 5 A method for producing light olefins from waste plastics according to claim 1, wherein the catalyst is one into which phosphorus (P) is introduced. Claim 6 A method for producing light olefins from waste plastics according to claim 1, wherein the catalyst is pre-steamed. Claim 7 A method for producing light olefins from waste plastics according to claim 1, wherein the catalyst is a spherical or elliptical molded body with a diameter of 30 μm to 200 μm. Claim 8 A method for producing light olefins from waste plastics according to claim 1, wherein the catalyst is synthesized by adding a zeolite seed. Claim 9 delete Claim 10 A method for producing a light olefin from waste plastic according to claim 1, wherein the light olefin is ethylene, propylene, or a C4 olefin. Claim 11 A method for producing light olefins from waste plastics according to claim 1, wherein the sum of the light olefin yields is 40 to 70 weight% with respect to 100 weight% of the oil-containing stream. Claim 12 A method for producing light olefins from waste plastics according to claim 1, wherein the reaction is carried out at a reaction temperature of 590 to 720 ℃. Claim 13 In claim 1, the reaction is space velocity (WHSV, Weight Hourly Space Velocity) 4 h, defined as the ratio of the mass flow rate of the oil-containing stream to the mass of the catalyst. -1 to 24 h -1 A method for producing light olefins from waste plastics, which is carried out as follows. Claim 14 A method for producing light olefins from waste plastics according to claim 1, wherein the catalyst comprises zeolite. Claim 15 A method for producing light olefins from waste plastics according to claim 14, wherein the zeolite comprises at least one selected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23, ZSM-48, zeolite X, zeolite Y, zeolite-L, zeolite-β, zeolite-Ω, mordenite, erionite, chabazite, and MFI zeolite.

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