Method for producing feedstock for naphtha cracking center

Abstract

There is provided a method of producing a feedstock for a naphtha cracking center, comprising: preparing a pyrolysis composition comprising a polyolefin or comprising a blend of a polyolefin and a hydrogen donor; and pyrolyzing the pyrolysis composition to obtain a pyrolysis product.

Description

[0001] Citation of Related Applications

[0002] This application claims priority to Korean Patent Application No. 10-2023-0011092 filed on January 27, 2023, the entire contents of which are incorporated herein as a part of this specification. Technical Field

[0003] The present application relates to a method for producing feedstock for a naphtha cracking center, and more particularly, to a method for further improving the yield of high-quality feedstock for a naphtha cracking center by pyrolyzing polyolefins in the presence of a hydrogen donor. Background Art

[0004] By pyrolyzing polyethylene (PE) and polypropylene (PP) from waste plastics at high temperature and pressure, pyrolysis fractions can be obtained as the initial raw materials for the naphtha cracking center (NCC). The pyrolysis fractions can be used as NCC raw material feed to generate basic fractions (including ethylene and propylene) through the naphtha cracking center process. These basic fractions are the basic raw materials for petrochemical products and can therefore be used to manufacture products in various industrial fields.

[0005] However, the pyrolysis fraction obtained by pyrolysis of polyethylene and polypropylene is of low quality and its yield does not meet the expected effect. Therefore, in order to preferably use the pyrolysis fraction as a raw material for a naphtha cracking center, a method is needed that can obtain high-quality pyrolysis fractions and further improve the yield of the pyrolysis fractions. Summary of the invention

[0006] Technical issues

[0007] In order to solve the problems mentioned in the background art, an object of the present invention is to provide a method for obtaining high-quality pyrolysis fractions while further improving the yield of pyrolysis fractions.

[0008] Technical Solution

[0009] In one general aspect, a method for producing a feedstock for a naphtha cracking center includes: preparing a pyrolysis composition comprising a polyolefin or a blend comprising a polyolefin and a hydrogen donor; and pyrolyzing the pyrolysis composition to obtain a pyrolysis product.

[0010] Beneficial Effects

[0011] According to the method for producing raw materials for naphtha cracking center of the present invention, a pyrolysis composition comprising a polyolefin or a blend comprising a polyolefin and a hydrogen donor can be pyrolyzed to obtain a pyrolysis product. Here, the polymer chains in the pyrolysis composition may be more easily destroyed by the hydrogen donor contained in the pyrolysis composition. Therefore, the amount of gasoline in the pyrolysis product can be effectively increased, and the amount of heavy hydrocarbons with more than 23 carbon atoms that are not suitable as raw materials for naphtha cracking center can also be significantly reduced. Therefore, according to the present invention, the yield of the pyrolysis fraction can be further increased, and a high-quality pyrolysis fraction can be obtained at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a flow chart of a method for producing a feedstock for a naphtha cracking center according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0013] The terms and words used in the specification and claims of the present invention should not be understood restrictively as having conventional or dictionary meanings, but should be understood as having meanings and concepts consistent with the technical concept of the present invention based on the principle that inventors can appropriately define the concepts of the terms in order to best describe their own inventions.

[0014] In the present invention, "#" is a term of a positive integer, and "C#" means a mixture including all hydrocarbon compounds having # carbon atoms. Therefore, the term "C8" means a mixture containing hydrocarbon compounds having 8 carbon atoms. In addition, the term "C#-" means all hydrocarbon molecules having # or less carbon atoms. Therefore, the term "C8-" means a mixture of hydrocarbons having 8 or less carbon atoms. In addition, the term "C#+" means all hydrocarbon molecules having more than # carbon atoms. Therefore, the term "C10+" means a mixture of hydrocarbons having more than 10 carbon atoms.

[0015] In the following, reference will be made to Figure 1 The present invention is described in more detail for better understanding of the present invention.

[0016] According to an exemplary embodiment of the present invention, a method for producing a feedstock for a naphtha cracking center is provided, comprising: preparing a pyrolysis composition comprising polyolefin or a blend comprising polyolefin and a hydrogen donor; and pyrolyzing the pyrolysis composition to obtain a pyrolysis product.

[0017] First, a method for producing a feedstock for a naphtha cracking center according to an exemplary embodiment of the present invention may include preparing a pyrolysis composition comprising polyolefin or a blend comprising polyolefin and a hydrogen donor. The blend is a blend comprising polyolefin and may refer to all compositions comprising polyolefin.

[0018] Polyolefins may be derived from waste plastics, which may include one or more resins such as polyolefins, polystyrene, polyvinyl chloride, polyethylene terephthalate, and ABS. Waste plastics are a type of polymer waste, and due to the increase in the amount generated, treatment methods may become problematic, so there is a need for more efficient methods of recycling waste plastics.

[0019] The polyolefin of the present invention or a blend comprising polyolefin can be obtained by pre-treating waste plastics. The pre-treatment process of waste plastics can refer to sorting and crushing waste plastics suitable for the present invention in waste plastics to increase the yield of raw materials in the naphtha cracking center in the pyrolysis of the pyrolysis composition described later. Herein, the composition of waste plastics suitable for the present invention may include 60% to 100% by weight of polyolefins. Since the waste plastics to be discarded can be recovered by the pre-treatment process of the above-mentioned waste plastics, the environmental pollution caused by discarding the waste plastics can be reduced. According to an exemplary embodiment of the present invention, polyolefins or a blend comprising polyolefins can come from the crushed products of waste plastics.

[0020] According to the present invention, polyolefin may include one or more of polyethylene (PE) and polypropylene (PP). Here, polyethylene may include high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) according to density. Here, when pyrolyzing low-density polyethylene, polyethylene may be more easily decomposed than in the case of pyrolyzing high-density polyethylene.

[0021] According to an exemplary embodiment, the polyolefin may include polyethylene and polypropylene, and the ratio of the amount of polyethylene to the amount of polypropylene in the pyrolysis composition may be 40:60 to 60:40.

[0022] The hydrogen donor of the present invention can provide hydrogen free radicals during the pyrolysis process of the pyrolysis composition, specifically polyolefin. When the pyrolysis composition is pyrolyzed, the hydrogen free radicals can help the polymer polyolefin in the pyrolysis composition to be better pyrolyzed.

[0023] According to an exemplary embodiment of the present invention, the hydrogen donor may include one or more of formic acid, benzoic acid, ethylene glycol and phenol, preferably formic acid. When formic acid is used as a hydrogen donor, formic acid can further promote the pyrolysis of the polymer polyolefin in the pyrolysis composition to improve the yield of the raw material of the naphtha cracking center obtained in the present invention.

[0024] The amount of hydrogen donor in the pyrolysis composition may be 5 wt% or more, 6 wt% or more, or 7 wt% or more, and 20 wt% or less, 15 wt% or less, or 12 wt% or less, relative to a total of 100 wt% of the pyrolysis composition.

[0025] Specifically, the amount of hydrogen donor in the pyrolysis composition may be 5 wt % to 20 wt %, more specifically, 7 wt % to 20 wt %, 7 wt % to 15 wt %, or 5 wt % to 15 wt %. When the amount of hydrogen donor in the pyrolysis composition is less than 5 wt %, the amount of hydrogen donor contained in the pyrolysis composition is too low, so during the pyrolysis process of the pyrolysis composition, it may be difficult to obtain the effect to be achieved by the hydrogen donor, that is, it may be difficult to pyrolyze polyolefins well by providing hydrogen radicals. When the amount of hydrogen donor in the pyrolysis composition exceeds 20 wt %, after the pyrolysis of the pyrolysis composition, the hydrogen donor will remain in the pyrolysis product, or the hydrogen donors will react with each other during the pyrolysis of the pyrolysis composition, thereby reducing the pyrolysis efficiency of the pyrolysis composition. In addition, the amount of gas generated during the pyrolysis of the pyrolysis composition may increase, thereby reducing the yield of the raw material of the naphtha cracking center.

[0026] Meanwhile, according to another exemplary embodiment of the present invention, the pyrolysis composition may further comprise one or more of a metal catalyst and an acid catalyst. The metal catalyst may comprise one or more of zeolite, aluminum phosphate and aluminum oxide. Under the action of the metal catalyst and / or the acid catalyst, the polyolefin in the pyrolysis composition may be efficiently pyrolyzed.

[0027] A method for producing a feedstock for a naphtha cracking center according to an exemplary embodiment of the present invention may include pyrolyzing a pyrolysis composition including a polyolefin or a blend including a polyolefin and a hydrogen donor to obtain a pyrolysis product.

[0028] The pyrolysis product may include gasoline (C5 to C12), diesel (C13 to C22) and heavy hydrocarbon compounds with more than 23 carbon atoms, which are classified according to the number of carbon atoms. In addition, it may further include gas. The gas may be the gas after the pyrolysis composition is pyrolyzed in the pyrolysis reactor, and the gas may include CO2, methane, ethane, propane, hydrogen and acetaldehyde.

[0029] Specifically, gasoline may be a mixture containing hydrocarbon compounds having 5 to 12 carbon atoms as a main component, and diesel may be a mixture containing hydrocarbon compounds having 13 to 22 carbon atoms as a main component. In addition, a heavy hydrocarbon compound having more than 23 carbon atoms may be a hydrocarbon compound containing hydrocarbon compounds having more than 23 carbon atoms as a main component. Here, the main component refers to a component present in an amount of 95% by weight or more or 100% by weight in a mixture, for example, in the case of gasoline, it may refer to a hydrocarbon compound having 5 to 12 carbon atoms in a content of 95% by weight or more or 100% by weight in gasoline.

[0030] More specifically, the pyrolysis product may be obtained through the following reaction: When the pyrolysis composition including polyolefin and hydrogen donor is pyrolyzed, the polymer polyolefin in the pyrolysis composition is decomposed into low molecular weight molecules by heat.

[0031] In the conventional pyrolysis process of polyolefins, the bonds between carbon and hydrogen (CH bonds) in the polymer may break before the bonds between carbon and carbon (single bonds or multiple bonds), thereby generating hydrogen free radicals. The hydrogen free radicals generated in this way can make other carbon-carbon bonds more easily pyrolyzed (i.e., carbon-carbon bonds are more easily broken). The action of hydrogen free radicals and the pyrolysis of polyolefins can be carried out continuously.

[0032] Since the present invention adds a hydrogen donor for providing hydrogen free radicals in the pyrolysis process to the pyrolysis composition containing polyolefin, in addition to the hydrogen free radicals generated by the breaking of carbon-hydrogen bonds, a higher amount of hydrogen free radicals participate in the pyrolysis of polyolefin, thereby promoting the smooth pyrolysis of polyolefin. Therefore, the efficiency of pyrolysis can be improved as a whole, so that the amount of gasoline in the pyrolysis product reaches the level required by the present invention, thereby obtaining high-quality raw materials for the naphtha cracking center.

[0033] Meanwhile, pyrolysis may be carried out in a pyrolysis reactor, which may include one or more of a rotary kiln, a continuous stirred tank reactor (CSTR), a tubular reactor, and a batch reactor.

[0034] In addition, pyrolysis can be carried out at a temperature of 380°C to 520°C. More specifically, it can be carried out at a temperature of 400°C to 500°C, or 430°C to 470°C. When pyrolysis is carried out under the temperature conditions within the above range, the hydrogen donor contained in the pyrolysis composition can release hydrogen radicals, which more easily destroys the polymer chains in the pyrolysis composition. Therefore, the amount of heavy hydrocarbon compounds having more than 23 carbon atoms in the pyrolysis product is reduced, while the total amount of gasoline and diesel is relatively increased, thereby further obtaining the pyrolysis fraction described later.

[0035] According to an exemplary embodiment of the present invention, the amount of gasoline, diesel and heavy hydrocarbon compounds having 23 or more carbon atoms in the pyrolysis product obtained by pyrolysis may be 50 wt% or more, 70 wt% or more, or 80 wt% or more and 90 wt% or less, 88 wt% or less, or 85 wt% or less, relative to a total of 100 wt% of the pyrolysis composition.

[0036] Meanwhile, according to an exemplary embodiment of the present invention, the gas chromatography (GC) area of ​​gasoline contained in the pyrolysis product can be 65% to 90% relative to the gas chromatography area of ​​gasoline, diesel and heavy hydrocarbon compounds with more than 23 contained in the total 100% of the pyrolysis product. More specifically, it can be 67% to 88%, or 70% to 85%. When the area of ​​gasoline contained in the pyrolysis product is within this range, the raw material of the naphtha cracking center obtained by the present invention can be used as a high-quality raw material for the naphtha cracking center. Generally, the boiling point of light naphtha added as a raw material to the naphtha cracking center is below 100°C, and the boiling point of gasoline in the pyrolysis product may also be close to it. Therefore, according to an exemplary embodiment of the present invention, the pyrolysis fraction containing a higher amount of gasoline can be a high-quality raw material for the naphtha cracking center. Therefore, the raw material light naphtha of the naphtha cracking center is replaced with a pyrolysis fraction containing gasoline derived from waste plastics, thereby satisfying the carbon reduction of the naphtha cracking center, and is therefore preferred from an environmental perspective.

[0037] The above-mentioned GC area can be analyzed by gas chromatography (GC) analysis. GC analysis refers to an analysis or method thereof for sorting the contents of an object to be measured. GC analysis may include a chromatographic column for separating various compounds and a detector for measuring the atomic mass of the material introduced from the chromatographic column. When the sample to be analyzed is measured by GC analysis, a GC graph depicting the amount of each component ultimately included in the sample can be obtained. Therefore, the relative comparison of various amounts can be measured by the area ratio of the GC graph.

[0038] Specifically, the gas chromatography area of ​​gasoline contained in the pyrolysis product is a value expressed by the ratio of the GC area of ​​gasoline contained in the pyrolysis product to the GC area of ​​gasoline, diesel and heavy hydrocarbon compounds having 23 or more carbon atoms contained in the pyrolysis product in the GC chart obtained by the GC analysis method.

[0039] The raw material production method of the naphtha cracking center according to an exemplary embodiment of the present invention may further include separating heavy hydrocarbon compounds having more than 23 carbon atoms from the pyrolysis product to obtain a pyrolysis fraction. When the pyrolysis product is added as a raw material to the naphtha cracking center without separating the heavy hydrocarbon compounds having more than 23 carbon atoms, the naphtha cracking center may experience a blocking phenomenon and promote the formation of tar. In addition, the yield of the base fraction obtained in the naphtha cracking center may be reduced. The blocking phenomenon may refer to the narrowing of the conveying path in the cracking furnace tube of the naphtha cracking center as carbon is deposited in the cracking furnace tube of the naphtha cracking center. Due to the occurrence of the blocking phenomenon, the operation of the naphtha cracking center may be stopped, and therefore, it is not desirable from an economic point of view. Therefore, it is necessary to separate and remove the heavy hydrocarbon compounds having more than 23 carbon atoms contained in the pyrolysis product separately. The pyrolysis fraction obtained by separating and removing the heavy hydrocarbon compounds having more than 23 carbon atoms may include gasoline (C5 to C12) and diesel (C13 to C22).

[0040] The separation and removal of heavy hydrocarbon compounds having 23 or more carbon atoms contained in the pyrolysis product can be performed by supplying the pyrolysis product to one or more distillation towers. First, when the process is performed by one distillation tower, gas can be separated from the upper part of the distillation tower, gasoline and diesel can be separated from the side part, and heavy hydrocarbon compounds having 23 or more carbon atoms can be separated from the lower part.

[0041] Meanwhile, when the process is carried out in two or more distillation towers, it can be carried out by one or more distillation towers for separating gasoline and diesel from the lower part and one or more distillation towers for separating heavy hydrocarbon compounds having 23 or more carbon atoms from the lower part. Gas can be separated from the upper part of the two or more distillation towers. Here, the gas separated from the upper part of the two or more distillation towers can be added as fuel for a boiler provided in a naphtha cracking center.

[0042] According to the present invention, the pyrolysis fraction can be a raw material feed of a naphtha cracking center. Specifically, the pyrolysis fraction can be a raw material feed of a naphtha cracking center (NCC) as a fuel of the NCC in different technical fields. The NCC can be carried out by including a cracking process, a quenching process, a compression process and a refining process. The pyrolysis fraction is used to generate a basic fraction of a petrochemical basic raw material containing ethylene and propylene through the NCC, and the basic fraction can be used to obtain various chemical raw materials, such as synthetic resins, synthetic fibers, synthetic rubbers and other chemical products.

[0043] Meanwhile, before the pyrolysis fraction is introduced into the raw material feed of the NCC, the pyrolysis fraction may be supplied to a distillation process. More specifically, the distillation process may be a process of distilling the pyrolysis fraction to obtain naphtha alone, and removing impurities from the naphtha or adding hydrogen to the naphtha for refining. Therefore, the naphtha obtained in the pyrolysis fraction may be further refined and supplied to the raw material feed of the NCC.

[0044] Hereinafter, the present invention will be described in more detail by examples. However, the following examples are provided only to illustrate the present invention. It will be apparent to those skilled in the art that various modifications and changes may be made without departing from the scope and spirit of the present invention, and the scope of the present invention is not limited thereto.

[0045] Experimental example

[0046] The GC areas of gasoline, diesel, and heavy hydrocarbon compounds having 23 or more carbon atoms contained in the pyrolysis products prepared in the following Examples and Comparative Examples were measured by the following method. Specifically, the GC area was measured by gas chromatography, using an autosampler and Agilent 7890B as analysis devices and helium as carrier gas.

[0047] The pyrolysis product obtained by pyrolysis of a pyrolysis composition comprising pyrolysis fuel oil (comprising a first aromatic compound, a polyolefin and a hydrogen donor) is supplied to a centrifuge to separate gas and solid and to remove residue to prepare a sample. The sample is supplied to an autosampler (set to 0.2 μl (injection sample amount) and 400°C (injection sample temperature)). The sample is injected into an oven contained in an Agilent 7890B by an autosampler. The sample injected into the oven is added to a chromatographic column (Frontier UA-5 (MS / HT), 30m×250μm×0.2μm) provided in the oven. The component separated from the chromatographic column is supplied to a detector. At this time, a flame ionization detector (FID) is used as a detector, and the temperature is set to 400°C. A gas chromatogram is obtained from the detector.

[0048] In the gas chromatogram, the GC area corresponding to gasoline, the GC area corresponding to diesel, and the GC area corresponding to heavy hydrocarbon compounds having more than 23 carbon atoms are calculated, and the sum of these (total GC area) is regarded as 100%. At this time, the ratio of the GC area of ​​each component to the total GC area of ​​100% (i.e., the GC area fraction) is calculated. At this time, each component may refer to gasoline, diesel, and heavy hydrocarbon compounds having more than 23 carbon atoms.

[0049] Meanwhile, dodecane (C12) and docosane (C22) were used as standard reagents.

[0050] Example

[0051] Example 1

[0052] according to Figure 1 The flow chart shown obtains the feedstock for the naphtha cracking center.

[0053] Specifically, a pyrolysis composition containing 9 g of polyethylene, 6 g of polypropylene and 1.5 g of formic acid as a hydrogen donor was prepared. The amount of hydrogen donor in the pyrolysis composition was 9.2 wt%.

[0054] Then, the pyrolysis composition is supplied to a tubular reactor and pyrolyzed to obtain a pyrolysis product. At this time, the pyrolysis temperature in the pyrolysis reactor is 450° C. for 60 minutes. The pyrolysis product contains gasoline, diesel, heavy hydrocarbon compounds with more than 23 carbon atoms, and gas. The amount of gasoline, diesel, and heavy hydrocarbon compounds with more than 23 carbon atoms in the pyrolysis product is 80%.

[0055] Meanwhile, the GC area fraction of gasoline in the pyrolysis product was 72.62%. The GC area fraction of diesel was 25.05%, and the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms was 2.33%. At this time, the GC area fraction was measured by gas chromatography (using Agilent 7890B device).

[0056] Subsequently, heavy hydrocarbon compounds having more than 23 carbon atoms are separated and removed from the pyrolysis product to obtain a pyrolysis fraction containing gasoline and diesel. The pyrolysis fraction is added to the raw material feed of the naphtha cracking center as a raw material of the naphtha cracking center.

[0057] Example 2

[0058] The feedstock for the naphtha cracking center was prepared in the same manner as in Example 1, except that phenol was used instead of formic acid as the hydrogen donor in the pyrolysis composition.

[0059] The GC area fraction of gasoline in the pyrolysis product obtained by pyrolyzing the pyrolysis composition is 67.29%, the GC area fraction of diesel in the pyrolysis product is 29.04%, and the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms is 3.67%.

[0060] Example 2 demonstrates that, compared to Example 1, using phenol instead of formic acid as a hydrogen donor in the pyrolysis composition, the GC area fraction of gasoline in the pyrolysis product is reduced, while the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms is increased.

[0061] Example 3

[0062] In Example 3, a feedstock for a naphtha cracking center was prepared in the same manner as in Example 1, except that the amount of hydrogen donor (formic acid) in the pyrolysis composition was 4 wt%.

[0063] The GC area fraction of gasoline in the pyrolysis product obtained by pyrolyzing the pyrolysis composition is 65.7%, the GC area fraction of diesel in the pyrolysis product is 30.8%, and the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms is 3.5%.

[0064] Example 3 demonstrates that by reducing the amount of hydrogen donor in the pyrolysis composition compared to Example 1, the GC-MS area of ​​gasoline that can serve as a high-quality feedstock for a naphtha cracking center is reduced compared to Examples 1 and 2.

[0065] Example 4

[0066] In Example 4, a feedstock for a naphtha cracking center was prepared in the same manner as in Example 1, except that the amount of hydrogen donor (formic acid) in the pyrolysis composition was 20 wt%.

[0067] The GC area fraction of gasoline in the pyrolysis product obtained by pyrolyzing the pyrolysis composition was 77.4%, the GC area fraction of diesel in the pyrolysis product was 19.9%, and the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms was 2.7%.

[0068] Example 4 demonstrates that by increasing the amount of hydrogen donor in the pyrolysis composition compared to Example 1, the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms in the pyrolysis product is increased compared to Example 1.

[0069] Comparative Example

[0070] Comparative Example 1

[0071] In Comparative Example 1, a feedstock for a naphtha cracking center was produced in the same manner as in Example 1, except that a pyrolysis composition containing no hydrogen donor was pyrolyzed.

[0072] The GC area fraction of gasoline in the pyrolysis product obtained by pyrolyzing the pyrolysis composition is 63.79%, the GC area fraction of diesel in the pyrolysis product is 31.92%, and the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms is 4.29%.

[0073] In Comparative Example 1, a raw material for a naphtha cracking center was produced without a hydrogen donor in the pyrolysis composition, and the results confirmed that, among all the Examples and Comparative Examples, the GC area fraction of gasoline in the pyrolysis product in this case was the lowest, and the GC area fraction of heavy hydrocarbon compounds having more than 23 carbon atoms was the highest. This confirmed that when the pyrolysis composition did not contain a hydrogen donor, the pyrolysis of polyethylene and polypropylene in the pyrolysis composition was not easy to proceed.

Claims

1. A method for producing a feedstock for a naphtha cracking center, comprising: preparing a pyrolysis composition comprising a polyolefin or a blend comprising a polyolefin and a hydrogen donor; as well as The pyrolysis composition is pyrolyzed to obtain a pyrolysis product.

2. The method for producing a feedstock for a naphtha cracking center according to claim 1, further comprising separating heavy hydrocarbon compounds having more than 23 carbon atoms from the pyrolysis products to obtain a pyrolysis fraction.

3. The method for producing a feedstock for a naphtha cracking center according to claim 1, wherein: The polyolefin includes one or more of polyethylene and polypropylene.

4. The method for producing a feedstock for a naphtha cracking center according to claim 1, wherein: The hydrogen donor comprises one or more of formic acid, benzoic acid, ethylene glycol and phenol.

5. The method for producing a feedstock for a naphtha cracking center according to claim 1, wherein: The amount of the hydrogen donor in the pyrolysis composition is from 5 wt % to 20 wt %.

6. The method for producing a feedstock for a naphtha cracking center according to claim 1, wherein: The pyrolysis is performed at a temperature of 380°C to 520°C.

7. The method for producing a feedstock for a naphtha cracking center according to claim 1, wherein: The pyrolysis products include gasoline, diesel and heavy hydrocarbon compounds having more than 23 carbon atoms, and The amount of gasoline, diesel and heavy hydrocarbon compounds having more than 23 carbon atoms in the pyrolysis product is 50 wt % to 90 wt %.

8. The method for producing a feedstock for a naphtha cracking center according to claim 7, wherein: The gasoline is a mixture containing 95% by weight or more of hydrocarbon compounds having 5 to 12 carbon atoms.

9. The method for producing a feedstock for a naphtha cracking center according to claim 7, wherein: The gas chromatographic area of ​​gasoline contained in the pyrolysis product is 65% to 90% relative to the gas chromatographic area of ​​gasoline, diesel and heavy hydrocarbon compounds having 23 or more carbon atoms contained in the pyrolysis product, which is 100% in total, and The gas chromatographic area is measured from a gas chromatogram obtained by a gas chromatograph analyzer (Agilent 7890B).

10. The method for producing a feedstock for a naphtha cracking center according to claim 2, wherein: The pyrolysis fraction is the raw material feed to the naphtha cracking center.

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