METHOD FOR PREPARING SINTESIS GAS AND AROMATIC HYDROCARBON

Abstract

A method for preparing synthesis gas and aromatic hydrocarbons is provided, and more particularly, a method for preparing synthesis gas and aromatic hydrocarbons that includes: supplying a pyrolysis fuel oil (PFO) stream containing PFO and a pyrolysis gas oil (PGO) stream containing PGO to a distillation tower as a feed stream (S10), the PFO stream and the PGO stream being discharged from a naphtha cracking center (NCC) process; and supplying a bottom discharge stream from the distillation tower to a combustion chamber for a gasification process and supplying a top discharge stream from the distillation tower to a BTX preparation process (S20).

Description

METHOD FOR PREPARING SYNTHESIS GAS AND AROMATIC HYDROCARBON [Technical Field] The present invention relates to a method for preparing synthesis gas and aromatic hydrocarbons, and more particularly, to a method for using pyrolysis fuel oil discharged from a gasoline fractionator in a naphtha cracking center (NCC) process as a feedstock for a gasification process and recovering aromatic hydrocarbons in the pyrolysis fuel oil. [Precedent Technique] A naphtha cracking center process (hereafter referred to as NCC) is a process for cracking naphtha, which is a fraction of gasoline, at a temperature of approximately 950°C to 1050°C to produce ethylene, propylene, butylene, and benzene, toluene, and xylene (BTX), which are basic raw materials for a petrochemical product. In the related art, benzene, toluene, xylene, and styrene have been prepared using crude pyrolysis gasoline (RPG), a byproduct of a process for producing ethylene and propylene using naphtha as a feedstock, and the pyrolysis fuel oil (PFO) has been used as a fuel. However, since pyrolysis fuel oil has a high sulfur content and a high carbon dioxide (CO2) emission factor for use as a fuel without pretreatment, the > tu NCNNCC 2 au The market is getting smaller due to environmental regulations, and a situation must be prepared for where sales are impossible in the future. Meanwhile, synthesis gas (syngas) is artificially prepared gas, distinct from natural gas such as naturally derived gas, methane gas, or ethane gas that is expelled from the earth in oil fields and coalfields, and is prepared by a gasification process. The gasification process is a method for converting a hydrocarbon, such as coal, petroleum, or biomass, into synthesis gas, primarily composed of hydrogen and carbon monoxide, through pyrolysis or a chemical reaction with a gasifying agent such as oxygen, air, or steam. A gasifying agent and feedstock are supplied to a combustion chamber at the front end of the gasification process to produce synthesis gas through combustion at a temperature of 700°C or higher. Because the kinematic viscosity of the feedstock supplied to the combustion chamber is higher, the differential pressure within the chamber increases, or atomization becomes uneven, leading to impaired combustion performance or an increased risk of explosion due to excessive oxygen. In the related technique, as a raw material σ For a gasification process to prepare synthesis gas using a liquid-phase hydrocarbon feedstock, refinery residues, such as vacuum residues (VR) and bunker-C oil, discharged from a crude oil refinery, have been primarily used. However, because refinery residue has a kinematic viscosity, pretreatment, such as heat treatment or the addition of a diluent or water, is required to use it as a feedstock for the gasification process. Furthermore, because refinery residue has high sulfur and nitrogen content, the production of acidic gases such as hydrogen sulfide and ammonia increases during gasification. Thus, in order to meet stringent environmental regulations, there is a growing need to replace refinery residue with a feedstock that has low sulfur and nitrogen content. Therefore, a method for using pyrolysis fuel oil as a feedstock for a gasification process has been considered. However, in order to use pyrolysis fuel oil as the feedstock for the gasification process, the pyrolysis fuel oil must be heated to decrease its kinematic viscosity, but it is difficult to satisfy a kinematic viscosity condition for using σ fuel oil. pyrolysis as the raw material for the gasification process at a flash point or lower due to a significantly high kinematic viscosity of the pyrolysis fuel oil. Therefore, the present inventors have found that when pyrolysis fuel oil (PFO) in the naphtha cracking center (NCC) process is used as the feedstock for the gasification process, greenhouse gas emissions can be reduced, the operating costs of the gasification process can be reduced, and the efficiency of the process can be improved, as compared to the case of using refinery waste as a feedstock according to the related art, thus completing the present invention. [Description] [Technical Problem] An objective of the present invention is to provide a method for preparing synthesis gas whereby greenhouse gas emissions can be reduced, the operating costs of a gasification process can be reduced, and the efficiency of the process can be improved, as compared to the case of using a refinery residue as a feedstock according to the related art, by using pyrolysis fuel oil (PFO) discharged in a naphtha cracking center (NCC) process as the feedstock. or premium for the gasification process. [Technical Solution] In general terms, a method for preparing synthesis gas and aromatic hydrocarbons includes: supplying a pyrolysis fuel oil (PEO) stream containing PFO and a pyrolysis gas oil (PGO) stream containing PGO to a distillation column as a feed stream (S10), the PFO stream and the PGO stream being discharged into a naphtha cracking center (NCC) process; and supplying a bottom discharge stream from the distillation column to a combustion chamber for a gasification process and supplying a top discharge stream from the distillation column to a BTX preparation process (S20). [Advantageous Effects] According to the present invention, pyrolysis fuel oil (PFO) and pyrolysis gas oil (PGO) in the naphtha cracking center (NCC) process are pretreated and used as the raw material for the gasification process, such that greenhouse gas emissions can be reduced, the operating costs of the gasification process can be reduced, and the efficiency of the process can be improved, as compared to the case of using refinery residue as the raw material according to the related technique. NCNN Furthermore, the light pyrolysis fuel oil generated during the pyrolysis fuel oil (PFO) pretreatment process and the pyrolysis gas oil (PGO) are used as feedstocks to prepare BTX along with crude pyrolysis gasoline (RPG), thus increasing BTX production. [Description of Drawings] FIG. 1 is a process flow diagram for a method for preparing synthesis gas and aromatic hydrocarbons according to an exemplary embodiment of the present invention. FIG. 2 is a process flow diagram for a method for preparing synthesis gas and aromatic hydrocarbons according to Comparative Example 1 of the present invention. FIG. 3 is a process flow diagram for a method for preparing synthesis gas and aromatic hydrocarbons according to Comparative Example 2 of the present invention. FIG. 4 is a process flow diagram for a method for preparing synthesis gas and aromatic hydrocarbons according to Comparative Example 3 of the present invention. [Best Mode] The terms and words used in the description and claims of the present invention will not be σ or to be considered limited by having general or dictionary meanings, but rather to have meanings and concepts that fulfill the technical ideas of the present invention, based on a principle that inventors are able to appropriately define the concepts of the terms in order to describe their own inventions in the best way. The term "stream" in the present invention may refer to a flow of a fluid in a process, or it may refer to a fluid itself flowing in a pipe. Specifically, "stream" may refer to either a fluid itself flowing in a pipe connecting respective apparatuses or a flow of a fluid. Furthermore, "fluid" may refer to a gas or a liquid, and a solid substance is not excluded from the term "fluid." In the present invention, the term C#, where # is a positive integer, represents all hydrocarbons having # carbon atoms. Therefore, the term C8 represents a hydrocarbon compound having 8 carbon atoms. Furthermore, the term C#- represents all hydrocarbon molecules having # or fewer carbon atoms. Therefore, the term C8- represents a hydrocarbon compound having 8 or fewer carbon atoms. Furthermore, the term C#+ represents all hydrocarbon molecules having # or more carbon atoms. Therefore, the term σ or C1O+ represents a hydrocarbon compound that has 10 or more carbon atoms. The present invention will then be described in more detail with reference to FIG. 1 in order to aid in the understanding of the present invention. According to the present invention, a method for preparing synthesis gas (singas) and aromatic hydrocarbons is provided. The method for preparing synthesis gas and aromatic hydrocarbons may include: supplying a pyrolysis fuel oil (PFO) stream containing PFO and a pyrolysis gas oil (PGO) stream containing PGO to a distillation column 50 as a feed stream (S10), the PFO stream and the PGO stream being discharged into a naphtha cracking center process (SI); and supplying a lower discharge stream from the distillation column 50 to a combustion chamber for a gasification process (S3) and supplying an upper discharge stream from the distillation column 50 to a BTX preparation process (S4) (S20). Synthesis gas is artificially prepared gas, distinct from natural gas such as naturally derived gas, methane gas or ethane gas that is expelled from the earth in oil fields or coal fields, and is prepared by the gasification process. The gasification process is a process for σ Converting a hydrocarbon such as coal, petroleum, or biomass as a feedstock into synthesis gas containing primarily hydrogen and carbon monoxide by pyrolysis or a chemical reaction with a gasifying agent such as oxygen, air, or steam. Specifically, in the present invention, the synthesis gas may contain hydrogen and carbon monoxide. A gasifying agent and a feedstock are supplied to a combustion chamber positioned at the forward end of the gasification process to produce synthesis gas by combustion at a temperature of 700°C or higher. As the kinematic viscosity of the feedstock supplied to the combustion chamber increases, the differential pressure in the combustion chamber increases, or atomization is not uniform, resulting in impaired combustion performance or an increased risk of explosion due to excessive oxygen. In the related art, refinery residues, such as vacuum residues (VR) and bunker oil-C, discharged from a crude oil refinery, have been primarily used as feedstocks for a gasification process to prepare synthesis gas from a liquid-phase hydrocarbon feedstock. However, because the refinery residue has a high kinematic viscosity, pretreatment, such as heat treatment or the addition of a diluent or water, is required to use it as the feedstock for the gasification process. Furthermore, because the refinery residue has high sulfur and nitrogen content, the production of acidic gases, such as hydrogen sulfide and ammonia, increases during the gasification process.Thus, in order to comply with stringent environmental regulations, a need has arisen to replace refinery residue with a feedstock that has low sulfur and nitrogen content. For example, among refinery residues, vacuum residue can contain approximately 3.5% sulfur by weight and approximately 3,600 ppm nitrogen, and bunker C oil can contain approximately 4.5% sulfur by weight. Meanwhile, pyrolysis fuel oil (PFO) discharged from a naphtha cracking plant—a process used to crack naphtha to prepare petrochemical base materials such as ethylene and propylene—is commonly used as a fuel. However, because pyrolysis fuel oil has a high sulfur content, making it unsuitable for use as a fuel without pretreatment, the market is shrinking due to environmental regulations, and a future scenario where sales become impossible must be anticipated. Therefore, one method for using σ oil Pyrolysis fuel has been considered as a feedstock for a gasification process. However, in order to use pyrolysis fuel oil as the feedstock for the gasification process, the pyrolysis fuel oil must be heated to decrease its kinematic viscosity. However, it is difficult to meet the kinematic viscosity requirement for using pyrolysis fuel oil as a feedstock for the gasification process at or below its flash point due to the significantly high kinematic viscosity of the pyrolysis fuel oil. Therefore, the present invention is proposed to reduce greenhouse gas emissions, lower the operating costs of a gasification process, and improve process efficiency, as compared to using refinery residue as a feedstock according to the related art, by developing a pretreatment process (S2) to utilize the pyrolysis fuel oil (PFO) stream containing PFO and the pyrolysis gas oil (PGO) stream containing PGO, which are discharged from the naphtha cracking center process, as feedstocks for the gasification process. Furthermore, a light PFO stream discharged in the pretreatment process (S2) is recovered to prepare aromatic hydrocarbons, thereby increasing the production of these hydrocarbons. According to an exemplary embodiment of the present invention, the crude pyrolysis gasoline (RPG) stream containing RPG, the pyrolysis fuel oil (PFO) stream containing PFO, and the pyrolysis gas oil (PGO) stream containing PGO can be discharged into the naphtha cracking center (SI) process. Specifically, the naphtha center cracking process is a process for cracking naphtha containing paraffin, naphthenes, and an aromatic compound (aromatics) to produce ethylene, propylene, butylene, and benzene, toluene, and xylene (BTX) used as petrochemical raw materials, and the naphtha center cracking process can be largely composed of a cracking process, a rapid cooling process, a compression process, and a refining process. The cracking process is a method for breaking down naphtha into hydrocarbons with fewer carbon atoms in a cracking furnace at 800°C or higher, and it can discharge cracked gas at a high temperature. Here, the naphtha can undergo a preheating process with high-pressure steam before entering the cracking furnace, and then the preheated naphtha can be fed into the cracking furnace. The rapid cooling process is a process for cooling the cracked gas to a high temperature, in order to suppress σ A hydrocarbon polymerization reaction in the high-temperature cracked gas discharged from the cracking furnace is used to recover waste heat and reduce the heat load in a subsequent process (compression process). Here, the rapid cooling process may include primary cooling of the high-temperature cracked gas with rapid cooling oil and secondary cooling with rapid cooling water. Specifically, in primary cooling, the cracked gas can be fed to a gasoline fractionator to separate light oil containing hydrogen, methane, ethylene, propylene, and similar compounds, crude pyrolysis gasoline (RPG), pyrolysis fuel oil (PFO), and pyrolysis gas oil (PGO) from the cracked gas. The light oil can then be conveyed to a subsequent compression process. The compression process can be a process to produce compressed gas that has a reduced volume by raising the pressure of light oil under high pressure to economically separate and refine the light oil. The refining process is a process of cooling compressed gas, which is compressed at high pressure, to a cryogenic temperature and then separating the components in stages by a difference in boiling point, and can produce hydrogen, ethylene, propylene, propane, C4 oil, σ or crude pyrolysis gasoline (RPG), and the like. As described above, in the rapid cooling process of the naphtha cracking center (SI) process, crude pyrolysis gasoline (RPG), pyrolysis fuel oil (PEO), and pyrolysis gas oil (PGO) can be discharged. Generally, pyrolysis fuel oil (PEO) contains approximately 0.1% by weight or less of sulfur and approximately 20 ppm or less of nitrogen. When used as a fuel, sulfur oxides (SOx) and nitrogen oxides (NOx) are released during combustion, potentially increasing environmental concerns. However, when pyrolysis fuel oil (PEO) is used as a synthesis gas feedstock, the environmental impact is minimal. Therefore, in the present invention, the above problems can be solved by pretreating the pyrolysis fuel oil (PEO) and pyrolysis gas oil (PGO) by means of the pretreatment process (S2) and using them as the feedstocks for the gasification process to prepare synthesis gas, and greenhouse gas emissions can be reduced, the operating costs of the gasification process can be reduced, and the efficiency of the process can be improved, as is compared to the case of using refinery residue as the feedstock σ and for the gasification process according to the related technique. In addition, a light PFO stream discharged in the pretreatment process (S2) is used as a feedstock for aromatic hydrocarbons, such that it can increase the production of aromatic hydrocarbons. According to an exemplary embodiment of the present invention, the PFO stream and the PGO stream of the present invention may contain pyrolysis fuel oil (PFO) and pyrolysis gas oil (PGO) discharged from a gasoline fractionator 10 in the naphtha cracking center (SI) process, respectively. As a specific example, in the total number of stages of gasoline fractionator 10, when an upper stage is expressed as a 1% stage and a bottom stage is expressed as a 100% stage, the pyrolysis fuel oil (PFO) can be discharged at a stage of 90% or more, 95% or more, or 95% to 100%, of the total number of stages of gasoline fractionator 10. In addition, the pyrolysis gas oil (PGO) can be discharged at a stage of 10% to 70%, 15% to 65%, or 20% to 60%, of the total number of stages of gasoline fractionator 10.For example, when the total number of stages of the gasoline fractionator 10 is 100, an upper stage may be the first stage and a bottom stage may be the 100th stage, and a stage that is 90% or more of the total number of stages of the gasoline fractionator 10 may refer to the 90th stage to the 100th stage of the gasoline fractionator 10. The PGO stream is discharged from a side portion of the gasoline fractionator 10 in the naphtha cracking center (SI) process and may be a bottom discharge stream that is discharged from a bottom portion of a first separator 20 after supplying a side discharge stream containing pyrolysis gas oil (PGO) to the first separator 20. In addition, the PFO stream is discharged from a bottom portion of the gasoline fractionator 10 in the naphtha cracking center (SI) process and may be a bottom discharge stream that is discharged from a bottom portion of a second separator 30 after supplying a bottom discharge stream containing pyrolysis fuel oil (PFO) to the second separator 30. The first separator 20 and the second separator 30 may be devices in which a process for separating and removing gas or vapor dissolved in a liquid is carried out, and may be carried out by methods such as direct contact, heating, and pressurization, for example, by steam, inert gas, or the like. As a specific example, the side discharge stream from the gasoline fractionator 10 is supplied to the first separator 20, such that an upper discharge stream containing a light fraction separated from the side discharge stream of the gasoline fractionator can be refluxed from the first separator 20 to the second separator 30. gasoline fractionator 10. In addition, the lower discharge stream from gasoline fractionator 10 is supplied to the second separator 30, such that an upper discharge stream containing a light fraction separated from the lower discharge stream of gasoline fractionator 10 can be refluxed from the second separator 30 to gasoline fractionator 10. According to an exemplary embodiment of the present invention, the PGO stream may contain 70 wt% or more, or 70 wt% to 95 wt%, of C12 to C13 hydrocarbons, and the PFO stream may contain 70 wt% or more, or 70 wt% to 98 wt%, of C13+ hydrocarbons. For example, the PGO stream containing 70 wt% or more of C12 to C12 hydrocarbons may have a kinematic viscosity at 40°C of 1 to 200 cSt and a flash point of 10 to 50°C. Furthermore, for example, the PFO stream containing 70 wt% or more of C13+ hydrocarbons may have a kinematic viscosity at 40°C of 400 to 100,000 cSt and a flash point of 70 to 200°C. As such, the PFO stream containing more heavy hydrocarbons than the PGO stream may have a higher kinematic viscosity and a higher flash point than pyrolysis gas oil under the same temperature conditions. According to an exemplary embodiment of the present invention, a boiling point of the PGO stream can be σ u be 200 to 288°C or 210 to 270°C, and a boiling point of the PFO stream can be 289°C to 550°C or 300 to 500°C. The boiling points of the PGO stream and the PFO stream can refer to the boiling points of a PGO stream and a PFO stream in bulk form, each composed of a plurality of hydrocarbons. Here, the types of hydrocarbons included in the PGO stream and the types of hydrocarbons contained in the PFO stream can be different from each other, and some types can be the same as in each. As a specific example, the types of hydrocarbons contained in the PGO stream and the PFO stream can be included as described above. According to an exemplary embodiment of the present invention, the crude pyrolysis gasoline (RPG) stream containing RPG discharged from the gasoline fractionator 10 in the naphtha cracking center process (SI) can be supplied to the BTX preparation process (S4). As a specific example, the crude pyrolysis gasoline (RPG) stream can be discharged in a stage of 5% or less, or 1% to 5%, of the total number of stages of the gasoline fractionator 10. The RPG stream is discharged from an upper portion of the gasoline fractionator 10 in the naphtha cracking center (SI) process. The upper discharge stream containing crude pyrolysis gasoline (RPG) is σ It can supply a subsequent NCC process (not illustrated) to remove hydrogen and C4- hydrocarbon substances, thereby separating the RPG stream. The RPG stream can be a mixture of C5+ hydrocarbons, and specifically, it can be a mixture in which the O5 to CIO hydrocarbons are rich. For example, the RPG stream may include one or more selected from the group consisting of isopentane, n-pentane, 1,4-pentadiene, dimethylacetylene, 1-pentene, 3-methyl-1-butene, 2-methyl-1-butene, 2-methyl-2-butene, isoprene, trans-2-pentene, cis-2-pentene, trans-1,3-pentadiene, cyclopentadiene, cyclopentane, n-hexane, cyclohexane, 1,3-cyclohexadiene, n-heptane, 2-methylhexane, 3-methylhexane, n-octane, n-nonane, benzene, toluene, ethylbenzene, m-xylene, o-xylene, p-xylene, styrene, dicyclopentadiene, and indane. Here, a C6 to O8 hydrocarbon content in the RPG stream can be 40% by weight or more, 45% by weight to 75% by weight, or 50% by weight to 70% by weight. The RPG stream can be supplied to the BTX (S4) preparation process to prepare one or more of benzene, toluene, and xylene. For example, in the BTX (S4) preparation process, either benzene or BTX can be prepared. BTX is an abbreviation for benzene, toluene, and xylene, and xylene can include ethylbenzene, m-xylene, o-xylene, and p-xylene. σ u According to an exemplary embodiment of the present invention, the PFO stream containing pyrolysis fuel oil (PFO) and the PGO stream containing pyrolysis gas oil (PGO) can be supplied to the distillation tower 50 as a distillation stream, the PFO stream and the PGO stream being discharged into the naphtha cracking center (SI) process. The feed stream supplied to distillation column 50 includes both the PGO and PFO streams and may contain both heavy and light oil. Therefore, the feed stream containing both heavy and light oil is supplied to distillation column 50, and the upper discharge stream containing a light PFO stream is discharged from an upper portion of distillation column 50, such that a lower discharge stream with a adjusted kinematic viscosity and flash point can be discharged from a lower portion of distillation column 50.As a specific example, the PFO stream that has a higher heavy oil content than the PGO stream may have a higher kinematic viscosity and a higher flash point than the PGO stream, and the PGO stream that has a higher light oil content than the PFO stream may have a lower kinematic viscosity and flash point. or lower flammability than the PFO stream. In the feed stream that includes both of the two conflicting streams, a stream that has a desired kinematic viscosity and flash point can be discharged from the lower portion of the distillation column 50 by removing the light oil, as described above. According to an exemplary embodiment of the present invention, the feed stream may be a mixed oil stream obtained by mixing the PFO stream and the PGO stream. In this case, for example, the ratio of the flow rate of the mixed oil stream to the flow rate of the PGO stream contained within the mixed oil stream (hereinafter referred to as the PGO stream flow rate ratio) may be, but is not limited to, 0.35 to 0.7, 0.4 to 0.65, or 0.4 to 0.6. Herein, the flow rate may refer to a flow rate of one unit weight per hour. As a specific example, a unit of flow rate may be kg / h. The boiling point of a mixed oil stream can be 200°C to 600°C, 210°C to 550°C, or 240°C to 500°C. The boiling point of a mixed oil stream can refer to the boiling point of a mixed oil stream in a bulk form composed of a plurality of hydrocarbons. According to an exemplary modality of the present σ According to this invention, the mixed oil stream can pass through a first heat exchanger 40 before being supplied to the distillation column 50, and then can be supplied to the distillation column 50. The mixed oil stream is produced by mixing the PGO stream and the PEO stream at a high temperature discharged from the first separator 20 or the second separator 30, and the temperature of the mixed oil stream at the time of supply to the distillation column 50 can be optimally adjusted and the process energy can also be reduced by reusing the sensible heat of the mixed oil stream in the process, if necessary. According to an exemplary embodiment of the present invention, the mixed oil stream can be supplied to a stage of 10% to 70%, 15% to 60%, or 20% to 50% of the total number of stages of the distillation tower 50. Within this range, the distillation tower 50 can be operated efficiently, and unnecessary energy consumption can be significantly reduced. According to an exemplary embodiment of the present invention, a ratio of a flow rate of the feed stream supplied to the distillation column 50 to a flow rate of the top discharge stream of the distillation column 50 (hereinafter referred to as a distillation ratio of the distillation column 50) can be σ or be 0.01 to 0.2, 0.01 to 0.15, 0.03 to 0.15, or 0.1 to 0.2. That is, the distillation ratio of distillation column 50 can be adjusted to 0.01 to 0.2, 0.01 to 0.15, or 0.03 to 0.15. The distillation ratio of the distillation column in the above range can be adjusted by means of a flow rate adjustment device (not illustrated) installed in a tube through which the top discharge stream of the distillation column 50 is carried, and the performance of the distillation column 50 can be achieved by adjusting a reflux ratio of the top discharge stream of the distillation column 50 using the distillation ratio and a second heat exchanger 51.Here, the reflux ratio can refer to the ratio of the flow rate of a reflux stream to the flow rate of an outlet stream. As a specific example, the reflux ratio of the top discharge stream from distillation column 50 can refer, when a portion of the top discharge stream from distillation column 50 branches off and refluxes back into distillation column 50 as a reflux stream, and the remainder is supplied to the BTX (S4) preparation process as an outlet stream, to the ratio of the flow rate of the reflux stream to the flow rate of an outlet stream (hereafter referred to as a reflux ratio). More specifically, the reflux ratio can be 0.01 to σ. or 10, 0.1 to 7, or 0.15 to 5. A gasifying agent and a feedstock can be supplied to the combustion chamber (not illustrated) located at the forward end of the gasification process (S3) to produce synthesis gas by combustion at a temperature of 700°C or higher. Here, the synthesis gas production reaction takes place under a high pressure of 20 to 80 atm, and the feedstock in the combustion chamber must be moved at a high flow rate of 2 to 40 m / s. Therefore, the feedstock must be pumped at a high flow rate under high pressure for the synthesis gas production reaction. When the kinematic viscosity of the feedstock supplied to the combustion chamber is higher than an appropriate range, a high-cost pump must be used due to reduced pumpability, or costs increase due to increased energy consumption, and pumping may be impossible under the desired conditions.Furthermore, since the pumping is not uniform, the raw material cannot be supplied uniformly to the combustion chamber. Additionally, because the differential pressure in the combustion chamber increases, or because the atomization of the raw material is not uniform due to its small particle size, combustion performance can deteriorate, productivity can decrease, and a quantity σ can be reduced. A large amount of gasifying agent may be required, and the risk of explosion may increase due to excessive oxygen. Here, an appropriate kinematic viscosity range may vary slightly depending on the type of synthesis gas being synthesized, the combustion process conditions in the combustion chamber, and similar factors. However, in general, a lower kinematic viscosity of the feedstock is preferable in terms of cost, productivity, and safety, at the feedstock temperature at the time of delivery to the combustion chamber during the gasification process (S3). The preferred kinematic viscosity is 300 cSt or less. A differential pressure rise in the combustion chamber is prevented within this range, and atomization is achieved uniformly, thus improving combustion performance and reactivity due to the more consistent combustion reaction. Furthermore, when the flash point of the raw material supplied to the combustion chamber is below an appropriate range, a flame may ignite in the burner before combustion occurs due to the low flash point. This can lead to an explosion due to flashback fire in the combustion chamber, and the refractories in the combustion chamber may be damaged. Here, a σ range The appropriate flash point may vary depending on the type of synthesis gas being synthesized in the combustion chamber, the combustion process conditions within the chamber, and similar factors. However, in general, the flash point of the preferred feedstock may be 25°C or more higher than the feedstock temperature at the time of delivery to the combustion chamber during the gasification process (S3). Within this range, a loss of feedstock, a risk of explosion, and damage to the refractories in the combustion chamber can be prevented. Therefore, in the present invention, in order to control the kinematic viscosity and flash point of the lower discharge stream from distillation column 50, which is the feedstock supplied to the combustion chamber in the gasification process (S3), at appropriate intervals, the distillation ratio of distillation column 50 can be adjusted. That is, by adjusting the distillation ratio of distillation column 50, the kinematic viscosity and flash point of the lower discharge stream from distillation column 50 can be controlled at appropriate intervals, at a temperature at which the lower discharge stream from distillation column 50 is supplied to the combustion chamber. Furthermore, by adjusting the distillation ratio of the column of σ In distillation 50, the composition in the top discharge stream of distillation tower 50 is controlled, and when the top discharge stream of distillation tower 50 is supplied to the BTX preparation process (S4), the production of BTX can be increased. According to an exemplary embodiment of the present invention, a third heat exchanger 52 can be operated as a general boiler. According to an exemplary embodiment of the present invention, the temperature of the lower discharge stream from distillation column 50 at the time of delivery to the combustion chamber may be 25°C or more lower than the flash point of the lower discharge stream from distillation column 50 at the time of delivery to the combustion chamber, and may be at a temperature that has a kinematic viscosity of 300 cSt or less. That is, the kinematic viscosity of the lower discharge stream from distillation column 50 at the time of delivery to the combustion chamber may be 300 cSt or less, or 1 cSt to 300 cSt, and the flash point of the lower discharge stream from distillation column 50 may be 25°C or more higher than the temperature at the time of delivery to the combustion chamber, or 25°C to 150°C.Here, the temperature of the lower discharge stream of the distillation tower at the time of supply to the combustion chamber can > your NCNNCC 28 σ u. be 20°C to 90°C or 30°C to 80°C. The kinematic viscosity of the lower discharge stream from distillation tower 50 at the temperature at the time of supply to the combustion chamber within the range may be 300 cSt or less and the temperature at the time of supply to the combustion chamber may also be less than the flash point by 25°C or more, and in this way, it can satisfy the process operating conditions for use as the feed material for the gasification process (S3). Specifically, by adjusting the distillation ratio of distillation column 50 from 0.01 to 0.2, 0.01 to 0.15 or 0.03 to 0.15, when the bottom discharge stream from distillation column 50 is supplied to the combustion chamber, the flash point of the bottom discharge stream from distillation column 50 may be 25°C or more higher than the temperature of the bottom discharge stream from distillation column 50 at the time of supply, and its kinematic viscosity may be 300 cSt or less at the temperature of the bottom discharge stream from distillation column 50 at the time of supply. When the distillation ratio of distillation column 50 is 0.01 to 0.2, a light material with a low flash point is removed in the situation where both the flash point and the kinematic viscosity σ The flash point and kinematic viscosity are low, such that the flash point increase interval is greater than the kinematic viscosity increase interval. Therefore, the flash point and kinematic viscosity when the bottom discharge stream from distillation column 50 is supplied to the combustion chamber can be controlled to the flash point and kinematic viscosity intervals described above. On the other hand, when the distillation ratio of distillation column 50 is less than 0.01, it is difficult to control the flash point when the bottom discharge stream from distillation column 50 is supplied to the combustion chamber to be higher than the temperature when the bottom discharge stream from distillation column 50 is supplied to the combustion chamber by 25°C or more, and when the distillation ratio of distillation column 50 is greater than 0.01.2, the kinematic viscosity increase range is more increased than the flash point increase range, and thus, it is difficult to control the kinematic viscosity at 300 cSt or less. As such, by adjusting the distillation ratio of distillation column 50, the flash point and kinematic viscosity of the lower discharge stream from distillation column 50 at the time of supply to the combustion chamber can be controlled, and in this way, σ The lower discharge stream from the distillation tower may have physical properties suitable for use as the feedstock for the gasification process (S3). Meanwhile, for example, when the PFO stream is supplied directly to the combustion chamber without the pretreatment process (S2) as illustrated in FIG. 2, the PGO stream is supplied directly to the combustion chamber without the pretreatment process (S2) as illustrated in FIG. 3, or the oil stream mixed from the PGO stream and the PFO stream is supplied directly to the combustion chamber without the pretreatment process (S2) according to the present invention as illustrated in FIG. 4, a temperature that satisfies both the kinematic viscosity and the flash point in the appropriate ranges described above cannot exist.As such, when the PFO stream, the PGO stream, or the mixed oil stream is supplied to the combustion chamber at a temperature that does not satisfy either the kinematic viscosity and flash point within the appropriate ranges, a differential pressure in the combustion chamber may rise, or atomization may not be carried out uniformly, impairing combustion performance, and an explosion risk may be increased due to excessive oxygen, or a flame may occur in the burner before the combustion reaction occurs, and an explosion risk may be present due to a flashback phenomenon in the combustion chamber, and the refractories in the combustion chamber may be damaged. In general, the PFO and PGO streams are the heaviest residues in the NGC process and have been used as a simple fuel. When used as such, their compositions and physical properties do not need to be adjusted. However, as in the present invention, to use the stream as the feedstock for synthesis gas, specific physical properties must be met, such as kinematic viscosity and flash point. The PGO stream meets the kinematic viscosity requirement but has a very low flash point, while the PFO stream has a high flash point but a very high kinematic viscosity. Therefore, neither stream can satisfy both the kinematic viscosity and flash point requirements, making it difficult to use either stream as a feedstock for synthesis gas.Furthermore, in a case where the full stream with respect to the PFO stream and the PGO stream is used as the syngas feedstock, a ratio of the flow rate of the PGO stream to a flow rate of the full stream of the PFO and PGO streams is generally approximately 0.35 to 0.7, and in this case also, the kinematic viscosity condition for use as the feedstock for the gasification process at or below the flash point cannot be met and it is difficult to use the stream as the syngas feedstock.In this respect, in the present invention, the full quantity of the PFO stream and the PGO stream is supplied to the distillation column 50 and pretreated, such that when the lower discharge stream from the distillation column 50 is supplied to the combustion chamber, the flash point of the lower discharge stream from the distillation column 50 can be controlled to a range higher than the temperature of the lower discharge stream from the distillation column 50 at the time of supply by 25°C or more, and the kinematic viscosity can also be controlled to a range of 300 cSt or less at the temperature of the lower discharge stream from the distillation column 50 at the time of supply, and in this way, the conditions for the use of the stream as the feedstock for synthesis gas can be met. According to an exemplary embodiment of the present invention, the lower discharge stream from the distillation column 50 can pass through a fourth heat exchanger 53 before being supplied to the gasification process (S3), and then can be supplied to the σ process or gasification (S3). In this case, the temperature of the lower discharge stream of the distillation tower 50 at the time of supply to the gasification process (S3) can be adjusted and the process energy can also be reduced by reusing the sensible heat of the lower discharge stream of the distillation tower 50 that can be discarded as waste heat in the process using the heat exchanger. According to an exemplary embodiment of the present invention, the top discharge stream from the distillation tower 50 can be supplied to the BTX (S4) preparation process for preparing aromatic hydrocarbons. According to an exemplary embodiment of the present invention, the lower discharge stream of the distillation tower 50 may have a C10+ hydrocarbon content of 80% by weight or more, or 80% by weight to 98% by weight, and a C8- hydrocarbon content of 5% by weight or less, or 0.01% by weight to 5% by weight, and the upper discharge stream of the distillation tower 50 may have a C6 to C8 aromatic hydrocarbon content of 50% by weight or more, 55% by weight to 95% by weight, or 55% by weight to 85% by weight. For example, the C8- hydrocarbon may include one or more selected from the group consisting of pentane, pentene, pentadiene, methylbutene, cyclopentane, cyclopentene, hexane, cyclohexane, heptane, methylhexane, octane, benzene, toluene, xylene, and styrene. As a specific example, the C8- hydrocarbon may include all the types of C8 hydrocarbons described above, but the present invention is not limited to them. Furthermore, for example, the C10+ hydrocarbon may include one or more selected from the group consisting of dicyclopentadiene, naphthalene, methylnaphthalene, tetramethylbenzene, fluorene, and anthracene. As a specific example, the C10+ hydrocarbon may include all the types of C10+ hydrocarbons described above, but the present invention is not limited to them. Furthermore, for example, C6 to C8 aromatic hydrocarbons may include one or more selected from the group consisting of benzene, toluene, xylene, and styrene. As a specific example, C6 to C8 aromatic hydrocarbons may include all types of C6 to C8 aromatic hydrocarbons described above, but the present invention is not limited to them. As such, the lower discharge stream from distillation tower 50 is used as the feedstock for synthesis gas, and the upper discharge stream from distillation tower 50 in which the C6 to C8 aromatic hydrocarbon content is 50% by weight or more is supplied to the BTX (S4) preparation process, such that the > tu NCNNC C σ u pyrolysis fuel oil can be used as the σ The raw material for the gasification process, and the aromatic hydrocarbons in the pyrolysis fuel oil can be recovered to increase the production of benzene, toluene, and xylene. According to an exemplary embodiment of the present invention, the combustion of the lower discharge stream from distillation column 50 supplied to the combustion chamber in the gasification process (S3) at a temperature of 700°C or higher, from 700°C to 2,000°C, or from 800°C to 800°C may also be included. Furthermore, the lower discharge stream from distillation column 50 may be supplied to the combustion chamber together with the gasifying agent. Herein, the gasifying agent may include one or more agents selected from the group consisting of oxygen, air, and water vapor, and as a specific example, the gasifying agent may be oxygen or water vapor. As such, the lower discharge stream from distillation column 50 is burned at a high temperature in the presence of the gasifying agent, such that synthesis gas can be prepared. The synthesis gas prepared according to the preparation method of the present invention contains carbon monoxide and hydrogen and may further contain one or more selected from the group consisting of carbon dioxide, ammonia, hydrogen sulfide, hydrogen cyanide, and carbonyl sulfide. σ u According to an exemplary embodiment of the present invention, the top discharge stream from the distillation tower 50 can be supplied to the BTX (S4) preparation process together with the RPG stream, and one or more selected from the group consisting of benzene, toluene, and xylene can be prepared. According to an exemplary embodiment of the present invention, the top discharge stream from the distillation column is supplied to a hydrodesulfurization unit in the BTX (S4) preparation process along with the RPG stream to cause hydrodesulfurization in the presence of separately supplied hydrogen and a catalyst. The catalyst may be a catalyst capable of selective hydrogenation. For example, the catalyst may include one or more selected from the group consisting of palladium, platinum, copper, and nickel. In some cases, the catalyst may be supported on one or more carriers selected from the group consisting of gamma alumina, activated carbon, and zeolite. A discharge stream from the hydrodesulfurization unit can be supplied to a C5 separation column. An upper discharge stream containing C5- aromatic hydrocarbons can be discharged from the C5 separation column, and a lower discharge stream containing C6+ aromatic hydrocarbons can be supplied to an O7 separation column. σ u An upper discharge stream containing C7- aromatic hydrocarbons can be supplied from the C7 separation column to an extractive distillation column, and a lower discharge stream containing C8+ aromatic hydrocarbons can be supplied to a xylene separation column. In the extractive distillation column of the BTX process unit, aromatic and non-aromatic hydrocarbons contained in the overhead discharge stream of the C7 separation column can be separated using an extraction solvent. Specifically, in the extractive distillation column, the aromatic hydrocarbons contained in the overhead discharge stream of the C7 separation column can be selectively extracted and separated as a bottom discharge stream, and the non-aromatic hydrocarbons can be separated as a top discharge stream. For example, the extraction solvent can include one or more sulfolone compounds selected from the group consisting of sulfolane, alkylsulfolane, N-formylmorpholine, N-methylpyrrolidone, tetraethylene glycol, triethylene glycol, and diethylene glycol. Additionally, the extraction solvent can also include water as a co-solvent. The lower discharge stream from the extractive distillation column contains C7 aromatic hydrocarbons and can be fed to a σ benzene separation column To separate benzene from an upper discharge stream of the benzene separation column, a lower discharge stream from the benzene separation column can be fed to a toluene separation column. Here, the lower discharge stream from the extractive distillation column fed to the benzene separation column can be supplied to a solvent recovery column to remove the extraction solvent, and then fed back to the benzene separation column. The lower discharge stream from the benzene separation column contains C7 aromatic hydrocarbons, and can be supplied to the toluene separation column to separate toluene from an upper discharge stream of the toluene separation column, and a lower discharge stream from the toluene separation column can be supplied to a xylene separation column. The lower discharge stream from the C7 separation column and the lower discharge stream from the toluene separation column can be supplied to the xylene separation column to separate the xylene from an upper discharge stream, and the remaining heavy C9+ hydrocarbon substances can be discharged from a bottom portion. According to an exemplary embodiment of the present invention, in the method for preparing synthesis gas e σ or aromatic hydrocarbons, if necessary; in addition, devices such as a valve, a pump, a separator, and a mixer can be installed. Previously herein, the method for preparing synthesis gas and aromatic hydrocarbons according to the present invention has been described and illustrated in the drawings, but the description and illustration in the drawings are the description and illustration of only core constitutions for the understanding of the present invention, and in addition to the process and devices described above and illustrated in the drawings, the process and devices not described and illustrated separately may be appropriately applied and used to carry out the method for preparing synthesis gas and aromatic hydrocarbons according to the present invention. The present invention will then be described in more detail by Examples. However, the following Examples are provided to illustrate the present invention. It is evident to those skilled in the art that various modifications and alterations can be made without departing from the scope and spirit of the present invention, and the scope of the present invention is not limited to the same. Examples Examples 1 to 5 According to the process flow diagram illustrated in FIG. 1, BTX and synthesis gas were prepared. Specifically, an upper discharge stream from a stage representing 1% of the total number of stages of a gasoline fractionator 10 in a naphtha cracking center (SI) process was fed to a subsequent NCC process (not illustrated), and an RPG stream was discharged into the subsequent NCC process. Additionally, a side discharge stream from a stage representing 40% of the total number of stages of the gasoline fractionator 10 was fed to a first separator 20, and then a pyrolysis gas oil (PGO) stream containing PGO was discharged from a lower portion of the first separator 20. At this point, the hydrocarbon content of CIO to C12 in the PGO stream was confirmed to be 86% by weight.Furthermore, a bottom discharge stream from one stage of the gasoline fractionator 10, representing 100% of the total number of stages, was fed to a second separator 30. A pyrolysis fuel oil (PEO) stream containing PEO was then discharged from a bottom portion of the second separator 30. At this point, the C13+ hydrocarbon content in the PFO stream was confirmed to be 89% by weight. Additionally, the PGO stream had a flash point of 25.5°C and a kinematic viscosity at 40°C of 75 cSt, while the PFO stream had a flash point of 98°C and a kinematic viscosity at 40°C of 660 cSt. A mixed oil stream obtained by mixing > your NCNNCC 41 σ u The PGO and PEO streams were fed to distillation column 50. A distillation ratio was then set for column 50, and an upper discharge stream was discharged. A lower discharge stream was fed to a combustion chamber in a gasification process (S3) along with oxygen and steam to produce synthesis gas containing hydrogen and carbon monoxide. At this time, the ratio of the PGO flow rate to the mixed oil flow rate was 0.42. The mixed oil stream had a flash point of 70°C and a kinematic viscosity at 40°C of 365 cSt. The reflux ratio of the mixed oil stream from distillation column 50 was set to 2.5. A mixed RPG stream obtained by mixing the RPG stream and the top discharge stream from distillation tower 50 was supplied to a BTX (S4) preparation process to prepare benzene, toluene, and xylene using a hydrodesulfurization unit, a C5 separation column, a C7 separation column, an extractive distillation column, a benzene separation column, a toluene separation column, and a xylene separation column. The content relationships of hydrocarbons σ The concentration of C6 to C8 aromatics in the lower and upper discharge streams of distillation column 50, the distillation ratio of distillation column 50, and the temperature and flash point of the lower discharge stream of distillation column 50 at the time of delivery to the combustion chamber were measured. The results are shown in Table 1. Furthermore, compliance with process operating standards was verified based on the measurement results. At this time, the delivery time of the lower discharge stream from distillation column 50 to the combustion chamber was adjusted to maintain the kinematic viscosity at 300 cSt using a fourth heat exchanger 53.Specifically, in order to derive temperature conditions to control kinematic viscosity at 300 cSt, the kinematic viscosity of the corresponding sample was measured by temperature, and then a correlation between temperature and viscosity was established and calculated using interpolation. In addition, the production of benzene, toluene, and xylene produced in the BTX (S4) preparation process is shown in Table 3. Kinematic viscosity and flash point were measured as follows, and applied to all Examples and Comparative Examples. σ o (1) Kinematic viscosity: A sample was obtained from the sample stream being measured, and the measurement was performed according to ASTM D7042 using an SVM 3001 instrument available from Anton Paar. Furthermore, the temperature of each sample was maintained at a temperature 10°C lower than the kinematic viscosity measurement temperature, and the sample was stored in a sealed container to prevent vaporization of light materials and minimize the occurrence of a gas phase. (2) Flash point: A sample was taken from the sample stream being measured and the measurement was performed according to ASTM D93 using apm-8 available from TANAKA. In addition, the temperature of each sample was maintained at a temperature 10°C lower than the expected flash point, and the sample was stored in a sealed container to prevent vaporization of light materials and minimize the occurrence of a gas phase. Comparative Examples Comparative Example 1 According to the process flow diagram illustrated in FIG. 2, synthesis gas was prepared. Specifically, the lower discharge stream discharged at 100% of the total number of stages of the gasoline fractionator 10 in the naphtha cracking center (SI) process was supplied to the second separator 30, and the σ The pyrolysis fuel oil (PFO) stream containing PFO is discharged from the lower portion of the second separator 30. The PFO stream was supplied to the combustion chamber in the gasification process (S3) along with oxygen and steam. At that time, the C13+ content in the PFO stream was confirmed to be 89% by weight, and the PFO stream had a flash point of 98 °C and a kinematic viscosity at 40 °C of 660 cSt. Furthermore, the top discharge stream discharged in stage 1% of the total number of stages of the gasoline fractionator 10 in the naphtha cracking center process (SI) was supplied to the subsequent NCC process (not illustrated), the RPG stream was discharged in the subsequent NCC process, and the RPG stream was supplied to the BTX preparation process (S4), in order to prepare benzene, toluene and xylene using the hydrodesulfurization unit, the C5 separation column, the C7 separation column, the extractive distillation column, the benzene separation column, the toluene separation column and the xylene separation column. The temperature of the PFO stream at the time of delivery to the combustion chamber was measured. The result is shown in Table 2. In addition, it was confirmed whether the process operating standards were met according to the σ The measurement results. At this time, the time when the PFO stream was supplied to the combustion chamber was adjusted to the temperature conditions to control the kinematic viscosity to 300 cSt using the heat exchanger. In addition, the production of benzene, toluene, and xylene produced in the BTX (S4) preparation process is shown in Table 3. Comparative Example 2 According to the process flow diagram illustrated in FIG. 3, synthesis gas was prepared. Specifically, the side discharge stream discharged at stage 40% of the total number of stages of the gasoline fractionator 10 in the naphtha cracking center (SI) process was supplied to the first separator 20, and the pyrolysis gas oil (PGO) stream containing PGO was discharged from the lower portion of the first separator 20. The PGO stream was supplied to the combustion chamber in the gasification process (S3) along with oxygen and steam. At this time, the CIO content at C12 in the PGO stream was confirmed to be 86% by weight, and the PGO stream had a flash point of 25.5°C and a kinematic viscosity at 40°C of 75 cSt. Furthermore, the upper discharge current discharged in the 1% stage of the total number of stages of the fractionator σ or gasoline 10 in the naphtha cracking center process (SI) was supplied to the subsequent NCC process (not illustrated), the RPG stream was discharged into the subsequent NCC process and the RPG stream was supplied to the BTX preparation process (S4) to thereby prepare benzene, toluene, and xylene using the hydrodesulfurization unit, the C5 separation column, the C7 separation column, the extractive distillation column, the benzene separation column, the toluene separation column, and the xylene separation column. The temperature of the PGO stream at the moment it was supplied to the combustion chamber was measured. The result is shown in Table 2. Furthermore, it was confirmed whether the process operating standards were met based on the measurement results. At this point, the time during which the PGO stream was supplied to the combustion chamber was adjusted to maintain the kinematic viscosity at 300 cSt using the heat exchanger. In addition, the production of benzene, toluene, and xylene produced in the BTX (S4) preparation process is shown in Table 3. Comparative Example 3 According to the process flow diagram illustrated in FTG. 4, synthesis gas was prepared. σ u Specifically, the side discharge stream from stage 40% of the total number of stages of gasoline fractionator 10 in the naphtha cracking center (SI) process was fed to the first separator 20. The pyrolysis gas oil (PGO) stream containing PGO was then discharged from the bottom portion of the first separator 20, and at this point, the C12 CIO content in the PGO stream was confirmed to be 86% by weight. Furthermore, the bottom discharge stream from stage 100% of the total number of stages of gasoline fractionator 10 was fed to the second separator 30. The pyrolysis fuel oil (PFO) stream containing PFO was then discharged from the bottom portion of the second separator 30, and at this point, the C13+ content in the PFO stream was confirmed to be 89% by weight. A mixed oil stream was then produced by mixing the PGO and PFO streams. At this time, the PGO stream had a flash point of 25.5°C and a kinematic viscosity at 40°C of 75 cSt, and the PFO stream had a flash point of 98°C and a kinematic viscosity at 40°C of 660 cSt. Furthermore, the ratio of the PGO flow rate to the mixed oil flow rate was 0.42. The mixed oil stream was then supplied to the combustion chamber in the gasification process (S3) along with oxygen and steam. Furthermore, the top discharge stream discharged in stage 1% of the total number of stages of the gasoline fractionator 10 in the naphtha cracking center process (SI) was supplied to the subsequent NCC process (not illustrated), the RPG stream was discharged in the subsequent NCC process and the RPG stream was supplied to the BTX preparation process (S4), to prepare benzene, toluene and xylene in this way using the hydrodesulfurization unit, the C5 separation column, the C7 separation column, the extractive distillation column, the benzene separation column, the toluene separation column and the xylene separation column. The flash point of the mixed oil stream and the temperature at which the mixed oil stream was supplied to the combustion chamber were measured. The results are shown in Table 2. Furthermore, it was confirmed whether the process operating standards were met based on the measurement results. At this point, the time during which the mixed oil stream was supplied to the combustion chamber was adjusted to maintain the kinematic viscosity at 300 cSt using the heat exchanger. In addition, the production of benzene, toluene, and xylene, produced in the BTX (S4) preparation process, is shown in Table 3. Comparative Example 4 Synthesis gas and aromatic hydrocarbons were prepared in the same manner as in Example 1, except that the top discharge stream from distillation tower 50 was not supplied to the BTX (S4) preparation process in Example 1. In addition, the production of benzene, toluene, and xylene produced in the BTX (S4) preparation process is shown in Table 3. [Table 1] Distillation ratio Aromatic hydrocarbon ratio from C6 to C8 Lower discharge stream temperature at delivery (°C) Lower discharge stream kinematic viscosity at delivery (cSt) Lower discharge stream flash point (°C) If process operating standards are met Upper discharge stream Lower discharge stream Example 1 0.05 0 1 48.3 300 73 Example 2 0.01 0.08 0.92 49.2 300 75 0 Example 3 0.1 1 0 60 300 90.5 0 Example 4 0.2 1 0 73.3 300 99 0 Example 5 0.3 1 0 97.6 300 105.5 X [Table 2] Flash point of the stream (°C) Kinematic viscosity of the stream at the time of delivery (cSt) Temperature of the stream at the time of delivery (°C) If the process operating standards are met Comparative Example 1 (PFO) 98 300 78 X Comparative Example 2 (PGO) 25.5 300 14 X Comparative Example 3 (Mixed Oil) 70 300 47 X [Table 3] Benzene Production (%) Toluene Production (%) Xylene Production (%) Example 1 100.0 100.0 100.0 Example 2 100.1 100.1 100.0 Example 3 100.2 100.8 109.3 Example 4 100.2 100.8 109.3 Example 5 100.2 100.8 109.3 Comparative Example 1 100.0 100.0 100.0 Example 100.0 100.0 100.0 σ u Comparative 2 Comparative Example 3 100.0 100.0 100.0 Comparative Example 4 100.0 100.0 100.0 In Tables 1 and 2, whether the process operating standards were met was indicated by O when the temperature at the time the stream supplied to the combustion chamber in each of Examples 1 to 5 and Comparative Examples 1 to 3 was supplied to the combustion chamber in which the kinematic viscosity at the time of supply to the combustion chamber was 300 cSt, was less than the flash point by 25 °C or more, and was indicated by X when the temperature did not meet the condition described above. Additionally, in Table 3, the production of each of benzene, toluene, and xylene was expressed as a relative production ratio of each of benzene, toluene, and xylene calculated on the basis of the production (100%) of each of benzene, toluene, and xylene in Comparative Example 1. With reference to Tables 1 and 2, in Examples 2 to 4 in which, according to the method for preparing synthesis gas of the present invention, the distillation ratio of distillation column 50 was adjusted to the appropriate range (0.01 to 0.2) to produce the lower discharge stream, and the lower discharge stream of distillation column 50 was supplied to the combustion chamber σ For the gasification process (S3), it could be confirmed that when the lower discharge stream from distillation column 50 was supplied to the combustion chamber, the flash point of the lower discharge stream from distillation column 50 was 25°C or more higher than the temperature of the lower discharge stream from distillation column 50 at the time of supply to the combustion chamber, and its kinematic viscosity was within 300 cSt or less at the temperature of the lower discharge stream from distillation column 50 at the time of supply to the combustion chamber. It was confirmed that, since both the flash point and kinematic viscosity were within these ranges, the process operating conditions for its use as the feedstock for the gasification process (S3) were met. In particular, as illustrated in FIG. 1, in Example 3 in which the distillation ratio of distillation column 50 in the pretreatment process (S2) was controlled to a range of 0.03 to 0.15, it was confirmed that when the lower discharge stream of distillation column 50 was supplied to the combustion chamber, the flash point of the lower discharge stream of distillation column 50 was higher than the temperature of the lower discharge stream of distillation column 50 at the time of supply to the combustion chamber by 30 °C or more to allow for more stable operation. Furthermore, in Examples 1 to 5 in which the lower discharge stream being discharged from distillation column 50 was formed in the state where the distillation ratio of distillation column 50 was not adjusted to the appropriate range (0.01 to 0.2), it was observed that when the kinematic viscosity at the temperature of the lower discharge stream from distillation column 50 at the time of supply to the combustion chamber was controlled to 300 cSt, the temperature of the lower discharge stream from distillation column 50 at the time of supply to the combustion chamber was not controlled to be less than the flash point by 25°C or more. Furthermore, when the PFO stream was supplied directly to the combustion chamber without the pretreatment process (S2) as illustrated in FIG. 2 (Comparative Example 1), the PGO stream was supplied directly to the combustion chamber without the pretreatment process (S2) as illustrated in FIG. 3 (Comparative Example 2), or the oil stream mixed from the PGO and PFO streams was supplied directly to the combustion chamber without the pretreatment process (S2) according to the present invention as illustrated in FIG. 4 (Comparative Example 3), it could be confirmed that a temperature that satisfies both the viscosity σ The kinematic viscosity and flash point within the appropriate ranges described above did not exist. As such, it was confirmed that each of the streams in Comparative Examples 1 to 3 that did not meet both the kinematic viscosity and flash point within the appropriate ranges did not meet the process operating conditions for use as feedstock for the gasification process (S3). When the raw material for the gasification process (S3) is supplied to the combustion chamber at a temperature that does not meet either the kinematic viscosity and flash point within the appropriate ranges, a differential pressure in the combustion chamber may rise or atomization may not be carried out uniformly, impairing combustion performance, and an explosion risk may increase due to excessive oxygen, or a flame may occur in the burner before the combustion reaction occurs, and an explosion risk may arise due to a flashback phenomenon in the combustion chamber, and refractories in the combustion chamber may be damaged. Furthermore, with reference to Table 3, it can be confirmed that in Examples 1 to 5, the production of benzene, toluene, or xylene in the BTX (S4) preparation process varies depending on the distillation ratio of distillation column 50, and the production is increased compared to the Comparative Examples. Specifically, it could be confirmed that when the distillation ratio of distillation column 50 was controlled to 0.01 or higher, aromatic hydrocarbons from C6 to C8 were discharged through the upper discharge stream of distillation column 50, and in particular, when the distillation ratio of distillation column 50 was 0.1 or higher, the full amount of aromatic hydrocarbons from C6 to C8 was discharged through the upper portion of distillation column 50. Therefore, it could be confirmed that controlling the distillation ratio of distillation column 50 at 0.1 to 0.2 was the optimal process condition for preparing BTX together with the synthesis gas.

Claims

1. A method for preparing synthesis gas and aromatic hydrocarbons, the method characterized in that it comprises: supplying a pyrolysis fuel oil (PFO) stream containing PFO and a pyrolysis gas oil (PGO) stream containing PGO to a distillation tower as a feed stream (S10), the PFO stream and the PGO stream being discharged from a naphtha cracking center (NGC) process; and supplying a lower discharge stream from the distillation tower to a combustion chamber for a gasification process and supplying an upper discharge stream from the distillation tower to a BTX preparation process (S20).

2. The method according to claim 1, characterized in that the ratio of the flow rate of the upper discharge stream of the distillation tower to the flow rate of the feed stream supplied to the distillation tower is 0.01 to 0.

2.

3. The method according to claim 1, characterized in that the ratio of the flow rate of the upper discharge stream of the distillation column to the flow rate of the feed stream supplied to the distillation column is 0.1 to 0.

2. σ u 4. The method according to claim 1, characterized in that a kinematic viscosity of the lower discharge stream from the distillation tower at the time of delivery to the combustion chamber is 300 cSt or less and wherein a flash point of the lower discharge stream from the distillation tower is higher than a temperature at the time of delivery to the combustion chamber by 25 °C or more.

5. The method according to claim 1, characterized in that the temperature of the lower discharge stream of the distillation tower at the time of supply to the combustion chamber is 20°C to 90°C.

6. The method according to claim 1, characterized in that the lower discharge stream from the distillation tower passes through a fourth heat exchanger before being supplied to the combustion chamber.

7. The method according to claim 1, characterized in that the PGO stream contains 70% by weight or more of C12 to C13 hydrocarbons and the PFO stream contains 70% by weight or more of C13+ hydrocarbons.

8. The method according to claim 1, characterized in that a flash point of the PGO stream is 10 at 50°C and > tu N C N N N CC 58 σ u where a flash point of the PFO stream is 70 at 200°C.

9. The method according to claim 1, characterized in that a kinematic viscosity of the PGO stream at 40°C is 1 to 200 cSt and wherein a kinematic viscosity of the PFO stream at 40°C is 400 to 100,000 cSt.

10. The method according to claim 1, characterized in that a crude pyrolysis gasoline (RPG) stream containing RPG discharged from the naphtha cracking center (NCC) process is supplied to the BTX preparation process.

11. The method according to claim 1, characterized in that the PGO stream is a bottom discharge stream discharged from a bottom portion of a first separator after supplying a side discharge stream discharged from a side portion of a gasoline fractionator in the naphtha cracking center process to the first separator and wherein the PFO stream is a bottom discharge stream discharged from a bottom portion of a second separator after supplying a bottom discharge stream discharged from a bottom portion of the gasoline fractionator in the naphtha cracking center process to the second separator.

12. The method according to claim 11, characterized in that the lower discharge stream of the gasoline fractionator is discharged in a stage of 90% or more of a total number of stages of the gasoline fractionator and 5 wherein the side discharge stream of the gasoline fractionator is discharged in a stage of 10% to 70% of the total number of stages of the gasoline fractionator.

13. The method according to claim 1, characterized in that a reflux ratio of the distillation column is 0.01 to 10.

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