Title of Invention: Method for producing aromatic hydrocarbons
technical field
[One]
Cross Citation with Related Applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2020-0072891 dated June 16, 2020 and Korean Patent Application No. 10-2020-0141070 dated October 28, 2020, All content disclosed in the literature is incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a method for producing an aromatic hydrocarbon, and more particularly, to a method for simultaneously producing benzene, xylene and styrene in one process.
background
[5]
Naphtha Cracking Center (hereinafter referred to as 'NCC') thermally decomposes naphtha, a gasoline fraction, at a temperature of about 950 ° C. to 1,050 ° C. to produce ethylene, propylene, butylene, and It is a process to produce BTX (Benzene, Toluene, Xylene), etc.
[6]
Conventionally, raw pyrolysis gasoline (RPG), which is a by-product of the process of producing ethylene and propylene using naphtha as a raw material, was used to manufacture benzene and styrene through separate processes.
[7]
The benzene manufacturing process is largely a hydrodesulfurization process (Gasoline Hydrogenation, GHT), a pre-separation process (Prefraction, PF), an extractive distillation process (EDP) and a dialkylation process (Hydrodealkylation, HDA) using an RPG raw material stream. ), including In this case, by supplying to the hydrodesulfurization process (GHT) without separate separation of C7+ hydrocarbons from the raw material stream, there was a problem in that the amount of hydrogen used due to an increase in the flow rate supplied to the hydrodesulfurization process (GHT) increases. In addition, since the C6 hydrocarbon and the C7+ hydrocarbon are separated after the hydrodesulfurization process (GHT), and the C7+ hydrocarbon is subjected to a dialkylation reaction, and then mixed again to separate benzene, there is a problem of double energy consumption. .
[8]
In addition, the styrene extractive distillation process is a process for directly producing styrene from RPG through an extractive distillation process (EDP) process, and may be located in front of the benzene manufacturing process. At this time, in order to separate the styrene-rich C8 hydrocarbons before supplying the RPG to the EDP, the prefractionation (PF) step of the RPG into C7- hydrocarbons, C8 hydrocarbons and C9+ hydrocarbons is performed in advance. . However, in this case, the separated C7- hydrocarbons and C8 hydrocarbons are mixed again because they are introduced into the benzene manufacturing process and undergo a hydrodesulfurization process (GHT) step. After performing the GHT step, the C7- hydrocarbon and the C8 hydrocarbon are separated again in the benzene manufacturing process. As such, performing the step of separating the C7- hydrocarbon and the C8 hydrocarbon twice is cost and energy in the process lead to waste
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
The problem to be solved in the present invention is a method of simultaneously producing benzene, xylene, and styrene in one process in order to solve the problems mentioned in the technology that is the background of the invention, simplifying the process, and saving energy is to provide
means of solving the problem
[10]
According to an embodiment of the present invention for solving the above problems, in the present invention, a raw material stream is supplied to a C6 separation column, an overheads stream of the C6 separation column is supplied to the first hydrodesulfurization unit, and the bottoms discharge stream is C7 feeding to a separation column; feeding the C7 separation column overhead effluent stream to a dialkylation reaction unit and feeding the bottom effluent stream to a C8 separation column; separating benzene from the first hydrodesulfurization unit effluent stream and the dialkylation reaction unit effluent stream; removing the bottoms draw stream from the C8 separation column and feeding the top draw stream to a second extractive distillation column; and separating styrene from the second extractive distillation column bottoms effluent stream and separating xylene from the top effluent stream.
Effects of the Invention
[11]
According to the method for producing an aromatic hydrocarbon of the present invention, benzene, xylene and styrene can be simultaneously produced in one process, and in this process, the process is simplified by omitting the pre-separation process step, which was a necessary process for benzene production, and steam Energy can be saved by reducing usage.
[12]
In addition, only the C6- hydrocarbon stream excluding C7+ hydrocarbons from the raw material stream is supplied to the first hydrodesulfurization unit, thereby reducing the flow rate supplied to the first hydrodesulfurization unit, thereby reducing the amount of hydrogen used in the first hydrodesulfurization unit, and the catalyst's It has the effect of increasing the lifespan.
[13]
In addition, by installing the second hydrodesulfurization unit, the second extractive distillation column overhead stream is supplied to the first hydrodesulfurization unit, undergoes a pre-separation process, is converted to benzene by dialkylation, and then benzene is separated. Without it, the second extractive distillation column overheads stream may be fed to a second hydrodesulfurization unit to further produce xylene.
[14]
In addition, by installing a C6 separation column in front of the C7 separation column, and supplying a raw material stream to the C6 separation column, C6- hydrocarbons and C7 hydrocarbons are separated, respectively, and the C6- hydrocarbons are supplied to the first hydrodesulfurization unit, and the C7 hydrocarbons are By supplying to the dialkylation reaction unit, it is possible to remove the columns for line separation at the rear end of the first hydrodesulfurization unit.
Brief description of the drawing
[15]
1 is a process flow diagram according to a method for producing an aromatic hydrocarbon according to Examples 1 and 2 of the present invention.
[16]
2 is a process flow chart according to the method for producing an aromatic hydrocarbon according to Comparative Example 1.
[17]
3 is a process flow chart according to the method for producing an aromatic hydrocarbon according to Comparative Example 2.
[18]
4 is a process flow chart according to the method for producing an aromatic hydrocarbon according to Comparative Example 3.
Modes for carrying out the invention
[19]
The terms or words used in the description and claims of the present invention should not be construed as being limited to their ordinary or dictionary meanings, and the inventor should properly understand the concept of the term in order to best describe his invention. Based on the principle that can be defined, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention.
[20]
In the present invention, the term 'stream' may mean a flow of a fluid in a process, and may also mean a fluid itself flowing in a pipe. Specifically, the 'stream' may mean both the fluid itself and the flow of the fluid flowing within a pipe connecting each device. In addition, the fluid may refer to a gas or a liquid.
[21]
In the present invention, the term 'C# hydrocarbon' in which '#' is a positive integer denotes all hydrocarbons having # carbon atoms. Accordingly, the term 'C8 hydrocarbon' denotes a hydrocarbon compound having 8 carbon atoms. Also, the term 'C#+ hydrocarbon' refers to any hydrocarbon molecule having # or more carbon atoms. Accordingly, the term 'C9+ hydrocarbon' denotes a mixture of hydrocarbons having 9 or more carbon atoms. Also, the term 'C#-hydrocarbon' refers to any hydrocarbon molecule having # or fewer carbon atoms. Thus, the term 'C7-hydrocarbons' denotes mixtures of hydrocarbons having up to 7 carbon atoms.
[22]
In the present invention, xylene may include ethyl benzene, m-xylene, o-xylene, and p-xylene. .
[23]
[24]
Hereinafter, the present invention will be described in more detail to help the understanding of the present invention.
[25]
According to the present invention, there is provided a method for producing an aromatic hydrocarbon. In the method for producing the aromatic hydrocarbon, the benzene, xylene, and styrene are simultaneously produced in one process, but the process is simplified and process energy can be reduced compared to the conventional case of producing benzene and styrene in each plant. there is an effect
[26]
Specifically, the conventional benzene manufacturing process is largely a hydrodesulfurization process (Gasoline Hydrogenation, GHT), a pre-separation process (Prefraction, PF), an extractive distillation process (EDP) and a dealkylation process using an RPG raw material stream. (Hydrodealkylation, HDA) was performed. In this case, by supplying to the hydrodesulfurization process (GHT) without separate separation of C7+ hydrocarbons from the raw material stream, there was a problem in that the amount of hydrogen used due to an increase in the flow rate supplied to the hydrodesulfurization process (GHT) increases. In addition, since the C6 hydrocarbon and the C7+ hydrocarbon are separated after the hydrodesulfurization process (GHT), and the C7+ hydrocarbon is subjected to a dialkylation reaction, and then mixed again to separate benzene, there is a problem of double energy consumption. .
[27]
In addition, the styrene extractive distillation process is a process for directly producing styrene from RPG through an extractive distillation process (EDP) process, and may be located in front of the benzene manufacturing process. In order to separate the C8 hydrocarbons before supplying the RPG to the EDP, a prefractionation (PF) step of the RPG into C7- hydrocarbons, C8 hydrocarbons and C9+ hydrocarbons is performed in advance. However, the separated C7- hydrocarbons and C8 hydrocarbons are mixed again because they are introduced into the benzene manufacturing process and undergo a hydrodesulfurization process (GHT) step. After performing the GHT step, the C7- hydrocarbon and the C8 hydrocarbon are separated again in the benzene manufacturing process. As such, performing the step of separating the C7- hydrocarbon and the C8 hydrocarbon twice is cost and energy in the process lead to waste
[28]
As such, conventionally, benzene and styrene were prepared through respective processes using RPG. In this case, there are problems such as unnecessary process steps and excessive energy consumption as described above.
[29]
In contrast, in the present invention, a process capable of simultaneously producing benzene and styrene, which cannot be technically derived from each process for producing benzene and styrene, and even xylene is designed, and in this process, the process is further simplified and maximized the production of benzene, xylene and styrene compared to the amount of raw material used while minimizing the use of process energy.
[30]
According to an embodiment of the present invention, a method for producing an aromatic hydrocarbon may be described with reference to FIG. 1 . As the method for producing the aromatic hydrocarbon, a raw material stream is supplied to a C6 separation column (DeC6), an overhead stream of the C6 separation column (DeC6) is supplied to a first hydrodesulfurization unit (1 st GHT), and the bottom discharge stream is feeding to a C7 separation column (DeC7); feeding the C7 separation column (DeC7) overhead stream to a dialkylation reaction unit (HDA), and feeding the bottoms exhaust stream to a C8 separation column (DeC8); separating benzene from the first hydrodesulfurization unit (1 st GHT) effluent stream and the dealkylation reaction unit (HDA) effluent stream; removing the bottom draw stream from the C8 separation column (DeC8) and feeding the top draw stream to a second extractive distillation column (2 nd EDC); and separating styrene from the second extractive distillation column (2 nd EDC) bottom effluent stream and separating xylene from the top effluent stream.
[31]
According to an embodiment of the present invention, the raw material stream may include Raw Pyrolysis Gasoline (RPG). The pyrolysis gasoline may be a by-product of a process of producing ethylene and propylene using naphtha as a raw material among units constituting a naphtha cracking center (NCC). The RPG as the feed stream may be a C5+ hydrocarbon mixture, specifically a mixture rich in C5 hydrocarbons to C10 hydrocarbons. For example, the RPG is, isopentane (Iso-Pentane), normal pentane (n-Pentane), 1,4-pentadiene (1,4-Pentadiene), dimethyl acetylene (Dimethylacetylene), 1-pentene (1- Pentene), 3-methyl-1-butene (3-Methyl-1-butene), 2-methyl-1-butene (2-Methyl-1-butene), 2-methyl-2-butene (2-Methyl-2 -butene), isoprene (Iso-Prene), trans-2-pentene (trans-2-Penstene), cis-2-pentene (cis-2-Penstene), trans-1,3-pentadiene (trans-1, 3-Pentadiene), cyclopentadiene, cyclopentane, cyclopentene, normal hexane (n-Hexane), cyclohexane, 1,3-cyclohexadiene (1,3- cyclohexadiene), normal heptane (n-Heptane), 2-methylhexane (2-methmethylh), 3-methylhexane (3-methylhexane), normal octane (n-Octane), normal nonane (n-Nonane), benzene (Benzene) ), toluene, ethylbenzene,
[32]
According to an embodiment of the present invention, in order to efficiently produce xylene along with benzene and styrene from the feed stream containing the C5 hydrocarbons to C10 hydrocarbons, the feed stream is first converted into C6-hydrocarbons, C7 hydrocarbons and C8+ hydrocarbons. can be separated. In this case, the stream including the C6- hydrocarbon and the stream including the C7 hydrocarbon may be a stream for producing benzene, and the stream including the C8+ hydrocarbon may be a stream for producing styrene and xylene.
[33]
According to an embodiment of the present invention, a C6 separation column (DeC6) and a C7 separation column (DeC7) are provided in order to separate the feed stream into C6- hydrocarbons, C7 hydrocarbons and C8+ hydrocarbons. Specifically, the feed stream is fed to a C6 separation column (DeC6), and the overheads stream containing C6- hydrocarbons from the C6 separation column (DeC6) is fed to a first hydrodesulfurization unit (1 st GHT), and C7+ The bottom draw stream comprising hydrocarbons was fed to a C7 separation column (DeC7). In addition, in the C7 separation column (DeC7), a top discharge stream containing C7 hydrocarbons and a bottom discharge stream containing C8+ hydrocarbons are separated, and the top discharge stream containing C7 hydrocarbons is a dealkylation reaction unit (HDA) and the bottoms effluent stream containing C8+ hydrocarbons was fed to a C8 separation column (DeC8).
[34]
As a result, the feed stream passes through a C6 separation column (DeC6) and a C7 separation column (DeC7) and is divided into a stream containing C6- hydrocarbons, a stream containing C7 hydrocarbons, and a stream containing C8+, A stream containing C6- hydrocarbons is supplied to a first hydrodesulfurization unit (1 st GHT) to produce benzene, and a stream containing C7 hydrocarbons may pass through a dialkylation reaction unit (HDA) to produce benzene. and a stream comprising C8+ hydrocarbons may be fed to a C8 separation column (DeC8) to produce styrene and xylene.
[35]
In addition, the C6 separation column (DeC6) can be recycled in the C6 separation column (DeC6) used in the pre-separation step in the existing BTX manufacturing process.
[36]
According to an embodiment of the present invention, the C6 separation column (DeC6) overhead discharge stream is supplied to the first hydrodesulfurization unit (1 st GHT) and hydrodesulfurization process step of hydrodesulfurization in the presence of separately supplied hydrogen and catalyst can be rough The catalyst may be a catalyst capable of selective hydrogenation. For example, the catalyst may include at least one selected from the group consisting of palladium, platinum, copper and nickel. In some cases, the catalyst may be used by being supported on at least one support selected from the group consisting of gamma alumina, activated carbon, and zeolite.
[37]
According to an embodiment of the present invention, it may be prepared by separating benzene from the first hydrodesulfurization unit (1 st GHT) discharge stream. Specifically, the first hydrodesulfurization unit (1 st GHT) outlet stream is fed to a first extractive distillation column (1 st EDC), and benzene is separated from the first extractive distillation column (1 st EDC) bottoms outlet stream. can
[38]
More specifically, the first hydrodesulfurization unit (1 st GHT) may include a first hydrodesulfurization reactor and a second hydrodesulphurization reactor, and the top discharge stream of the C6 separation column (DeC6) is transferred to the first hydrodesulfurization reactor. feeding the first hydrodesulfurization reactor effluent stream to a second hydrodesulfurization reactor, feeding the second hydrodesulphurization reactor effluent stream to a first extractive distillation column (1 st EDC), and the first extractive distillation Benzene may be separated from the column (1 st EDC) bottoms draw stream. At this time, the second hydrodesulfurization reactor outlet stream may be fed to a first extractive distillation column (1 st EDC) after passing through a stripper.
[39]
In addition, the first hydrodesulfurization unit (1 st GHT) may further include a separately required device in addition to the first hydrodesulfurization reactor and the second hydrodesulfurization reactor. For example, the first hydrodesulfurization unit (1 st GHT) may further include a C5 separation column, and the C5 separation column may be located between the first hydrodesulfurization reactor and the second hydrodesulfurization reactor. Through this, the C6 separation column (DeC6) overhead stream passes through the first hydrodesulfurization unit (1 st GHT), and from the C6 separation column (DeC6) overhead discharge stream, C5 hydrocarbons and fuel gas (Fuel gas, F/ Impurities such as G) may be removed.
[40]
The operating temperature of the first hydrodesulfurization reactor may be 50 °C to 200 °C, 60 °C to 170 °C or 60 °C to 140 °C. The first hydrodesulfurization reactor may be operated at a temperature within the above range, whereby the hydrogenation reaction may proceed in a liquid phase. Specifically, in the first hydrodesulfurization reactor, a hydrogenation reaction may be performed in a liquid phase at a low temperature in order to remove olefins. For example, the olefin is a hydrocarbon having a double bond, and may include styrene and diolefin. These olefins may be converted into saturated hydrocarbons by breaking a double bond due to a hydrogenation reaction in the first hydrodesulfurization reactor.
[41]
The operating temperature of the second hydrodesulfurization reactor may be 250 °C to 400 °C, 280 °C to 360 °C or 280 °C to 320 °C. The second hydrodesulfurization reactor may be operated at a temperature in the above range, whereby the hydrogenation reaction may proceed in the gas phase. Specifically, in the second hydrodesulfurization reactor, the residual olefin that has not been removed in the first hydrodesulfurization reactor may be removed, and a hydrogenation reaction may be performed in a gas phase to remove sulfur. Through this, the second hydrodesulfurization reactor effluent stream from which olefins and sulfur have been removed may be fed to the first extractive distillation column (1 st EDC) in whole volume after passing through a stripper without additional pre-separation.
[42]
Specifically, in the case of the conventional benzene production process, the entire raw material stream undergoes hydrodesulfurization, and columns for a pre-separation process are required to separate C6 hydrocarbons and C7+ hydrocarbons therefrom, and dialkyl for the separated C7+ hydrocarbons. After the reaction was carried out, the process was complicated because it had to be mixed with the C6 hydrocarbon again. In addition, even if the conventional benzene production process and the styrene extractive distillation process are theoretically combined, in the styrene extractive distillation process, the raw material stream is supplied to the C7 separation column (DeC7), and the C7-hydrocarbon-containing C7 separation column (DeC7) upper part Since the discharge stream is supplied to the first hydrodesulfurization unit (1 st GHT), the flow rate of the first hydrodesulfurization unit (1 st GHT) increases , and C6 hydrocarbons and A C6 separation column (DeC6) is required to separate C7+ hydrocarbons. Accordingly, unnecessary processes in the conventional process are still required. However, in the present invention, the feed stream is fed to a C6 separation column (DeC6), and only the overheads stream containing C6-hydrocarbons is fed to the first hydrodesulfurization unit (1 st GHT), and the bottoms offstream is C7 separation. The first hydrodesulfurization unit 1 st GHT), and at the same time, no additional separation is required, saving energy and utility costs.
[43]
According to an embodiment of the present invention, a raw material stream including C5 and C6 hydrocarbons may be separately supplied to the first hydrodesulfurization unit (1 st GHT). In this case, the raw material stream supplied to the first hydrodesulfurization unit (1 st GHT) may not include styrene. For example, a feed stream comprising C5 and C6 hydrocarbons separately supplied to the first hydrodesulfurization unit (1 st GHT) is a bottom draw stream of a C4 separation column (not shown) in the NCC process, cyclopentadiene, pentadiene , isoprene, cyclopentene, 1-pentene, 3-methyl-1-butene, cyclopentane, 2-methyl-butene, normal pentane, benzene, and may include at least one selected from the group consisting of C6 non-aromatic hydrocarbons. Conventionally, the C4 separation column bottoms effluent stream is mixed with the RPG described above and used as a feed stream for a benzene manufacturing process and a styrene manufacturing process. However, since the C4 separation column bottom discharge stream contains benzene and does not contain styrene, when supplied to the C6 separation column (DeC6), additional processes such as unnecessary separation and mixing are performed. Accordingly, in the present invention, the C4 separation column (not shown) bottom discharge stream is separately supplied to the first hydrodesulfurization unit (1 st GHT) to reduce the flow rate supplied to the C6 separation column (DeC6), and unnecessary process steps are not performed. energy could be saved.
[44]
The content of the olefin in the feed stream separately supplied to the first hydrodesulfurization unit (1 st GHT) may be 40 wt% or more, 40 wt% to 70 wt%, or 40 wt% to 60 wt%.
[45]
According to an embodiment of the present invention, the stream discharged from the first hydrodesulfurization unit (1 st GHT) may include C6 aromatic hydrocarbons. As a specific example, the first hydrodesulfurization unit (1 st GHT) discharge stream may be a stream rich in benzene, which is supplied to the first extractive distillation column (1 st EDC) and undergoes an extraction process to separate benzene. have.
[46]
The first extractive distillation column (1 st EDC) may be prepared by separating benzene from the first hydrodesulfurization unit (1 st GHT) discharge stream using an extraction solvent . For example, the extraction solvent is at least one selected from the group consisting of sulfolane, alkyl-sulfolane, N-formyl morpholine, N-methyl pyrrolidone, tetraethylene glycol, triethylene glycol and diethylene glycol. may include In addition, the extraction solvent may further include water as a co-solvent.
[47]
In the first extractive distillation column (1 st EDC), aromatic hydrocarbons and non-aromatic hydrocarbons in the first hydrodesulfurization unit (1 st GHT) discharge stream may be separated using an extraction solvent . Specifically, the aromatic hydrocarbons in the first hydrodesulfurization unit (1 st GHT) discharge stream in the first extractive distillation column (1 st EDC) are selectively extracted and discharged to the bottom of the first extractive distillation column (1 st EDC), Non-aromatic hydrocarbons may be separated from the top of the first extractive distillation column (1 st EDC).
[48]
A device separately required may be further included at the rear end of the first extractive distillation column (1 st EDC). For example, the first extractive distillation column (1 st EDC) bottom discharge stream is an extract, and may contain an extraction solvent along with an aromatic hydrocarbon. Accordingly, the first extractive distillation column (1 st EDC) bottom discharge stream may be separated into an extraction solvent and an aromatic hydrocarbon while passing through a separate solvent recovery column.
[49]
According to an embodiment of the present invention, the C7 separation column (DeC7) overhead discharge stream may be supplied to a dialkylation reaction unit (HDA) to undergo a dealkylation reaction. The C7 separation column (DeC7) overheads stream may comprise C7 aromatic hydrocarbons. The dialkylation reaction unit (HDA) may be to produce benzene by performing a dealkylation reaction of C7 aromatic hydrocarbons in the supplied C7 separation column (DeC7) overhead discharge stream. The dialkylation reaction may be a reaction in which an alkyl group is removed from a benzene ring by adding hydrogen to an aromatic hydrocarbon containing an alkyl group. In addition, since the hydrodesulfurization reaction occurs in addition to the dialkylation reaction in the dialkylation reaction unit (HDA), unsaturated hydrocarbons can be converted into saturated hydrocarbons. In this case, the C7 separation column (DeC7) overhead stream is a stream rich in toluene, and benzene may be produced by desorbing an alkyl group bonded to a benzene ring of toluene during the dialkylation reaction. At this time, the dialkylation reaction unit (HDA) discharge stream is a stream rich in benzene, from which benzene may be separated.
[50]
The first extractive distillation column (1 st EDC) bottoms effluent stream, for example, a first extractive distillation column (1 st EDC) bottoms effluent stream comprising aromatic hydrocarbons separated through a solvent recovery column and a dealkylation reaction unit The (HDA) effluent stream is then passed through one or more benzene separation columns (BZ) through which benzene from the first extractive distillation column (1 st EDC) bottoms effluent stream and the dealkylation reaction section (HDA) effluent stream can be separated. In addition, the benzene separation column (BZ) bottom discharge stream contains a trace amount of C7+ hydrocarbons, and a toluene separation column (TOL) for separating C7 hydrocarbons therefrom may be additionally provided. In the TOL, an overhead effluent stream containing C7 hydrocarbons may be supplied to a dealkylation reaction unit (HDA), and C8+ hydrocarbon heavy materials may be discharged from the bottom. At this time, the first extractive distillation column (1 st EDC) bottom discharge stream and the dialkylation reaction unit (HDA) discharge stream are respectively fed to the benzene separation column (BZ) as separate streams, or benzene after forming a mixed stream It may be fed to the separation column (BZ).
[51]
According to an embodiment of the present invention, the C7 separation column (DeC7) bottoms discharge stream is supplied to the C8 separation column (DeC8) as a stream containing C8+ hydrocarbons, and the C8 separation column (DeC8) contains C8 hydrocarbons. It may be separated into a top effluent stream and a bottoms effluent stream comprising C9+ hydrocarbons. At this time, the stream containing the C9+ hydrocarbon is removed by discharging to the outside through the C8 separation column (DeC8) bottom discharge stream, hydrodesulphurizing the components not required in the BTX manufacturing process, and removing after separation unnecessary process can be removed.
[52]
According to an embodiment of the present invention, the C8 separation column (DeC8) overhead stream containing the C8 hydrocarbon may be supplied to a second extractive distillation column (2 nd EDC) to undergo an extraction process.
[53]
In the second extractive distillation column (2 nd EDC), an aromatic hydrocarbon and a vinyl aromatic hydrocarbon may be separated from the C8 separation column (DeC8) overhead effluent stream using an extraction solvent. Specifically, in the second extractive distillation column (2 nd EDC), styrene-rich C8 vinyl aromatic hydrocarbons in the C8 separation column (DeC8) overhead effluent stream are selectively extracted and separated into the bottom of the second extractive distillation column (2 nd EDC) and xylene-rich C8 aromatic hydrocarbons can be separated from the top of a second extractive distillation column (2 nd EDC). In this case, the extraction solvent is, for example, one selected from the group consisting of sulfolane, alkyl-sulfolane, N-formyl morpholine, N-methyl pyrrolidone, tetraethylene glycol, triethylene glycol and diethylene glycol. It may include more than one species. In addition, the extraction solvent may further include water as a co-solvent.
[54]
The second extractive distillation column (2 nd EDC) may separate styrene from the bottom draw stream, and separate xylene from the second extractive distillation column (2 nd EDC) top draw stream, respectively.
[55]
A device separately required may be further included at the rear end of the second extractive distillation column (2 nd EDC). For example, the second extractive distillation column (2 nd EDC) bottoms outlet stream is an extract, and may contain an extraction solvent along with C8 vinyl aromatic hydrocarbons. Accordingly, the second extractive distillation column (2 nd EDC) bottom discharge stream may be separated into an extraction solvent and a C8 vinyl aromatic hydrocarbon while passing through a separate solvent recovery column, through which the C8 vinyl aromatic hydrocarbon, that is, styrene is separated can do.
[56]
The second extractive distillation column (2 nd EDC) overhead discharge stream is a stream including xylene-rich C8 aromatic hydrocarbons, and may pass through a second hydrodesulfurization unit (2 nd GHT) to produce xylene. Specifically, in the second hydrodesulfurization unit (2 nd GHT), residual olefins and sulfur in the second extractive distillation column (2 nd EDC) overhead stream may be removed by hydrogenation, and the second hydrodesulfurization unit (2 nd ) Xylene (MX) can be produced directly from the second extractive distillation column (2 nd EDC) overheads stream passed through GHT).
[57]
Hydrogen and a catalyst are separately supplied to the second hydrodesulfurization unit (2 nd GHT), and a hydrodesulfurization process step of performing a hydrodesulfurization reaction in the presence of hydrogen and a catalyst may be performed. The catalyst may be a catalyst capable of selective hydrogenation. For example, the catalyst may include at least one selected from the group consisting of palladium, platinum, copper and nickel. In some cases, the catalyst may be used by being supported on at least one support selected from the group consisting of gamma alumina, activated carbon, and zeolite.
[58]
The second hydrodesulfurization unit (2 nd GHT), unlike the first hydrodesulfurization unit (1 st GHT), does not include two hydrodesulfurization reactors, and is provided with only one third hydrodesulfurization reactor, so the size of the plant can be reduced and energy use can be minimized. Specifically, the second extractive distillation column (2 nd EDC) overheads stream fed to the third hydrodesulfurization reactor contains xylene-rich C8 aromatic hydrocarbons, and olefins such as styrene and diolefins are hardly present. Therefore, the hydrogenation reaction for removing the olefin through the liquid phase reaction at a low temperature can be omitted. For example, the content of the olefin contained in the second extractive distillation column (2 nd EDC) overhead effluent stream may be 0.1 wt% or less or 0.01 wt% to 0.1 wt%.
[59]
Specifically, the second extractive distillation column (2 nd EDC) overhead effluent stream is fed to a third hydrodesulfurization reactor, and in the third hydrodesulfurization reactor, from 250 °C to 400 °C, 280 °C to 360 °C or 280 °C to The hydrogenation reaction may proceed at a temperature of 320 °C. The third hydrodesulfurization reactor may be operated at a temperature within the above range, whereby the hydrogenation reaction may proceed in the gas phase. Specifically, in the third hydrodesulfurization reactor, residual olefins in the second extractive distillation column (2 nd EDC) overhead stream are removed, and a hydrogenation reaction may be performed in a gas phase to remove sulfur. Thereby, olefins and desulfurized xylene-rich C8 aromatic hydrocarbons are discharged from the third hydrodesulphurization reactor, and xylene (MX) can be produced without further separation from the third hydrodesulphurization reactor discharge stream.
[60]
On the other hand, even if the conventional benzene production process and the styrene extractive distillation process are theoretically combined, the stream containing the C8 aromatic hydrocarbon separated in the styrene extractive distillation process, that is, the second extractive distillation column (2 nd EDC) overhead stream will be fed to the first hydrodesulfurization unit (1 st GHT) as a raw material for the benzene manufacturing process together with the C7 separation column (DeC7) overhead effluent stream.
[61]
When the second extractive distillation column (2 nd EDC) overhead stream is supplied to the first hydrodesulfurization unit (1 st GHT) as a raw material for a benzene manufacturing process together with the C7 separation column (DeC7) overhead discharge stream , the first hydrodesulfurization Due to an increase in the flow rate supplied to the part (1 st GHT), there is a problem in that the amount of hydrogen used increases and the life of the catalyst is reduced. In addition, the second extractive distillation column (2 nd EDC) overheads stream contains very small amounts of olefins, so that both the first hydrodesulfurization reactor and the second hydrodesulfurization reactor like the first hydrodesulfurization unit (1 st GHT) are used. This leads to unnecessary use of energy. In addition, since the stream discharged from the first hydrodesulfurization unit (1 st GHT) includes C8 aromatic hydrocarbons as well as C6 aromatic hydrocarbons and C7 aromatic hydrocarbons, the rear end of the first hydrodesulfurization unit (1 st GHT) discharge stream There is a problem in that a plurality of separation columns are required to separate them from the , and must go through a dialkylation reaction unit (HDA) again.
[62]
In addition, even if the conventional benzene manufacturing process and the styrene extractive distillation process are theoretically designed to be combined more similarly to the present application, the second extractive distillation column (2 nd EDC) overhead stream is C7 separation column (DeC7) overhead discharge together with the stream will be fed to the dialkylation reaction unit (HDA).
[63]
When the second extractive distillation column (2 nd EDC) overheads stream is fed to the dialkylation reaction unit (HDA) together with the C7 separation column (DeC7) overheads stream, additional production of benzene is possible, but the C7 separation column ( DeC7) mixing with the overhead effluent stream, dialkylation reaction, mixing with the bottom effluent stream of the first extractive distillation column (1 st EDC), and benzene separation, resulting in a long path and complicated process There is a problem, and it does not produce xylene.
[64]
[65]
According to an embodiment of the present invention, in the method for producing an aromatic hydrocarbon, if necessary, a distillation column (not shown), a condenser (not shown), a reboiler (not shown), a valve (not shown), a pump (not shown), Devices such as a separator (not shown) and a mixer (not shown) may be additionally installed.
[66]
[67]
As mentioned above, although the method for producing an aromatic hydrocarbon according to the present invention has been shown in the description and drawings, the description and drawings are only described and illustrated for the essential components for understanding the present invention. In addition to the process and apparatus, processes and apparatus not separately described and not shown may be appropriately applied and used for carrying out the method for producing an aromatic hydrocarbon according to the present invention.
[68]
[69]
Hereinafter, the present invention will be described in more detail by way of Examples. However, the following examples are intended to illustrate the present invention, and it is apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention, and the scope of the present invention is not limited thereto.
[70]
[71]
Example
[72]
Example 1
[73]
With respect to the process flow diagram shown in FIG. 1, the process was simulated using Aspen Plus simulator of Aspen Corporation.
[74]
Specifically, a feed stream comprising C5 to C10 hydrocarbons is supplied to a C6 separation column (DeC6), and a feed stream comprising C5 and C6 hydrocarbons without styrene is fed to a first hydrodesulfurization unit (1 st GHT). supplied.
[75]
The C6 separation column (DeC6) overhead effluent stream containing C6- hydrocarbons was fed to the first hydrodesulfurization unit (1 st GHT), and the bottoms effluent stream containing C7+ hydrocarbons was fed to the C7 separation column (DeC7). In addition, from the C7 separation column (DeC7), the top discharge stream containing C7 hydrocarbons was supplied to the dealkylation reaction unit (HDA), and the bottom discharge stream containing C8+ hydrocarbons was supplied to the C8 separation column (DeC8).
[76]
The C6 separation column (DeC6) overhead effluent stream containing the C6-hydrocarbons is fed to a first hydrodesulfurization unit (1 st GHT), and the first hydrodesulfurization unit (1 st GHT) containing the C6 aromatic hydrocarbon hydrocarbons is discharged The stream was fed entirely to the first extractive distillation column (1 st EDC).
[77]
The first extractive distillation column (1 st EDC) bottoms discharge stream contains C6 aromatic hydrocarbons, and as a stream from which non-aromatic hydrocarbons are removed, the dialkylation reaction unit (HDA) discharge stream and the benzene separation column (BZ) are benzene was separated from the upper part of the benzene separation column (BZ), and the bottom effluent stream was supplied to a toluene separation column (TOL). In the toluene separation column (TOL), C7 aromatic hydrocarbons were separated from the upper part and supplied to the dialkylation reaction unit (HDA), and heavy materials including C8+ hydrocarbons were separated and removed from the lower part.
[78]
The C7 separation column (DeC7) bottoms discharge stream containing C8+ hydrocarbons is supplied to a C8 separation column (DeC8), and the bottoms discharge stream containing C9+ hydrocarbons from the C8 separation column (DeC8) is discharged to the outside and removed, The C8 separation column (DeC8) overhead effluent stream containing the C8 hydrocarbons was fed to a second extractive distillation column (2 nd EDC).
[79]
The bottom discharge stream of the second extractive distillation column (2 nd EDC) contains styrene, and is supplied to a solvent recovery column to remove the solvent, and then styrene is separated.
[80]
In addition, the second extractive distillation column (2 nd EDC) overhead stream is a xylene-rich stream, which is supplied to the second hydrodesulfurization unit (2 nd GHT), and the second hydrodesulfurization unit (2 nd GHT) discharge Xylene was produced from the stream.
[81]
In the process simulation, the flow rate (ton/hr) of the stream according to the process flow is shown in Table 1 below. In addition, the total amount of steam used in the process was measured as the total amount of energy used in the process, and it is shown in Table 2 below as a reference (100.0) for the total amount of steam used in the remaining examples and comparative examples.
[82]
[83]
Example 2
[84]
The same process as in Example 1 was performed, except that the feed stream containing C5 and C6 hydrocarbons without styrene was supplied to the C6 separation column (DeC6) instead of the first hydrodesulfurization unit (1 st GHT). .
[85]
As a result of the process simulation, the flow rate (ton/hr) of the stream according to the process flow is shown in Table 1 below. In addition, as the total energy consumption in the process, the total amount of steam used in the process was measured, and it is shown in Table 2 below as a relative amount compared to the amount of steam used in Example 1 of 100.0.
[86]
[87]
comparative example
[88]
Comparative Example 1
[89]
With respect to the process flow diagram shown in FIG. 2, the process was simulated using Aspen Plus simulator of Aspen Corporation.
[90]
Specifically, a feed stream comprising C5 to C10 hydrocarbons as a feed stream was supplied to a first hydrodesulfurization unit (1 st GHT), and the first hydrodesulfurization unit (1 st GHT) outlet stream was transferred to a C6 separation column (DeC6). supplied with In the C6 separation column (DeC6), a top draw stream comprising C6 aromatic hydrocarbons is fed to a first extractive distillation column (1 st EDC), and a bottom draw stream comprising C7+ aromatic hydrocarbons is fed to a C9 separation column (DeC9). did.
[91]
From the C9 separation column (DeC9), C8+ aromatic hydrocarbons were discharged to the bottom, and a stream containing C7 and C8 aromatic hydrocarbons was supplied to the dialkylation reaction unit (HDA).
[92]
The bottom discharge stream of the first extractive distillation column (1 st EDC) and the dialkylation reaction unit (HDA) discharge stream are mixed to separate benzene while passing through a benzene separation column (BZ), and the benzene separation column (BZ) The bottom draw stream was fed to a toluene separation column (TOL). In the toluene separation column (TOL), C7 aromatic hydrocarbons were separated from the upper part and supplied to the dialkylation reaction unit (HDA), and heavy materials including C8+ hydrocarbons were separated and removed from the lower part.
[93]
As a result of the process simulation, the flow rate (ton/hr) of the stream according to the process flow is shown in Table 1 below.
[94]
[95]
Comparative Example 2
[96]
With respect to the process flow diagram shown in FIG. 3, the process was simulated using Aspen Plus simulator of Aspen Corporation.
[97]
Specifically, a feed stream comprising C5 to C10 hydrocarbons is supplied to a C7 separation column (DeC7), and a feed stream comprising C5 and C6 hydrocarbons without styrene is fed to a first hydrodesulfurization unit (1 st GHT). supplied.
[98]
The C7 separation column (DeC7) overhead draw stream comprising C7- hydrocarbons is fed to a first hydrodesulfurization unit (1 st GHT), and the C7 separation column (DeC7) bottoms draw stream comprising C8+ hydrocarbons is fed to a C8 separation column ( DeC8).
[99]
The overheads stream from which C9+ hydrocarbons have been removed from the C8 separation column (DeC8) is fed to a second extractive distillation column (2 nd EDC). In the second extractive distillation column (2 nd EDC), a stream containing styrene was separated from the bottom discharge stream and supplied to a solvent recovery column to separate styrene from which the solvent was removed. In addition, the second extractive distillation column (2 nd EDC) overhead stream is a xylene-containing stream and is fed to the first hydrodesulfurization unit (1 st GHT) together with the C7 separation column (DeC7) overhead effluent stream.
[100]
The first hydrodesulfurization unit (1 st GHT) discharge stream includes C6 to C8 aromatic hydrocarbons and is supplied to a C6 separation column (DeC6). The C6 separation column (DeC6) is divided into a top draw stream comprising C6 aromatic hydrocarbons and a bottom draw stream comprising C7+ aromatic hydrocarbons, and the top draw stream is fed to a first extractive distillation column (1 st EDC), the bottom The effluent stream is fed to the dialkylation reaction unit (HDA).
[101]
The bottom discharge stream of the first extractive distillation column (1 st EDC) is mixed with the dialkylation reaction unit (HDA) discharge stream to pass through a benzene separation column (BZ) to separate benzene, and the benzene separation column (BZ) ) the bottoms effluent stream was fed to a toluene separation column (TOL). In the toluene separation column (TOL), C7 aromatic hydrocarbons were separated from the upper part and supplied to the dialkylation reaction unit (HDA), and heavy materials including C8+ hydrocarbons were separated and removed from the lower part.
[102]
As a result of the process simulation, the flow rate (ton/hr) of the stream according to the process flow is shown in Table 1 below.
[103]
[104]
Comparative Example 3
[105]
With respect to the process flow diagram shown in FIG. 4, the process was simulated using Aspen Plus simulator of Aspen Corporation.
[106]
Specifically, a feed stream comprising C5 to C10 hydrocarbons is supplied to a C7 separation column (DeC7), and a feed stream comprising C5 and C6 hydrocarbons without styrene is fed to a first hydrodesulfurization unit (1 st GHT). supplied.
[107]
The C7 separation column (DeC7) overhead draw stream comprising C7- hydrocarbons is fed to a first hydrodesulfurization unit (1 st GHT), and the C7 separation column (DeC7) bottoms draw stream comprising C8+ hydrocarbons is fed to a C8 separation column ( DeC8).
[108]
The overheads stream from which C9+ hydrocarbons have been removed from the C8 separation column (DeC8) is fed to a second extractive distillation column (2 nd EDC). In the second extractive distillation column (2 nd EDC), a stream containing styrene was separated from the bottom discharge stream and supplied to a solvent recovery column to separate styrene from which the solvent was removed. In addition, the second extractive distillation column (2 nd EDC) overhead stream is a xylene-containing stream and is fed to the first hydrodesulfurization unit (1 st GHT) together with the C7 separation column (DeC7) overhead effluent stream.
[109]
The first hydrodesulfurization unit (1 st GHT) discharge stream includes C6 to C8 aromatic hydrocarbons and is supplied to a C6 separation column (DeC6). The C6 separation column (DeC6) is divided into a top draw stream comprising C6 aromatic hydrocarbons and a bottom draw stream comprising C7+ aromatic hydrocarbons, and the top draw stream is fed to a first extractive distillation column (1 st EDC), the bottom The effluent stream is fed to a xylene separation column (MX).
[110]
In the xylene separation column (MX), xylene is separated from the bottom discharge stream, and the top discharge stream is supplied to the dialkylation reaction unit (HDA) to undergo a dealkylation reaction.
[111]
The bottom discharge stream of the first extractive distillation column (1 st EDC) is mixed with the dialkylation reaction unit (HDA) discharge stream to pass through a benzene separation column (BZ) to separate benzene, and the benzene separation column (BZ) ) the bottoms effluent stream was fed to a toluene separation column (TOL). In the toluene separation column (TOL), C7 aromatic hydrocarbons were separated from the upper part and supplied to the dialkylation reaction unit (HDA), and heavy materials including C8+ hydrocarbons were separated and removed from the lower part.
[112]
As a result of the process simulation, the flow rate (ton/hr) of the stream according to the process flow is shown in Table 1 below. In addition, as the total energy consumption in the process, the total amount of steam used in the process was measured, and it is shown in Table 2 below as a relative amount compared to the amount of steam used in Example 1 of 100.0.
[113]
[114]
[Table 1]
Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3
S1 20.4 N/A 176.4 20.4 20.4
S2 156 176.4 N/A 156 156
S11 74.3 74.3 86.2 74.3 74.3
S12 75.4 75.4 89.4 83.2 75.4
S13 61 61 68.8 68.2 61
S21 88.6 109 N/A N/A N/A
S22 67.4 67.4 N/A N/A N/A
S23 22.6 22.6 N/A 111.2 111.2
S24 44.8 44.8 N/A 44.8 44.8
S25 20.4 20.4 N/A 20.4 20.4
S26 10.3 10.3 N/A 10.3 10.3
S27 10.1 10.1 N/A N/A N/A
S28 10.1 10.1 N/A N/A N/A
S30 N/A N/A 144 109.4 109.4
S31 N/A N/A 57.8 35.2 35.2
S32 N/A N/A 20.4 N/A 25.2
S33 N/A N/A 37.4 N/A 10.1
S40 N/A N/A N/A 10.1 10.1
S41 24.4 24.4 N/A 24.4 24.4
[115]
[Table 2]
Example 1 Example 2 Comparative Example 3
Total Steam Usage 100.0 105.7 118.7
[116]
* Total steam usage: Ratio of relative total steam usage compared to the reference (Example 1: 100.0)
[117]
[118]
Referring to Tables 1 and 2, in the case of Examples 1 and 2, in which xylene is prepared along with benzene and styrene by the method according to the present invention, the total amount of aromatic hydrocarbons produced is equivalent to or superior to that of Comparative Example. Able to know.
[119]
In particular, in the case of Example 1, it can be seen that the total amount of steam used for heating in the process is the lowest compared to Examples 2 and 3, respectively. Specifically, in Example 1, the raw material stream containing C5 and C6 hydrocarbons without styrene is not supplied to the C6 separation column (DeC6), but is separately supplied to the first hydrodesulfurization unit (1 st GHT), By reducing the flow rate supplied to the C6 separation column (DeC6), it is possible to reduce the amount of steam used in the C6 separation column (DeC6). In addition, the C7 separation column (DeC7) overhead stream is not fed to the first hydrodesulfurization unit (1 st GHT) together with the C6 separation column (DeC6) overhead discharge stream , but is separately supplied to the dialkylation reaction unit (HDA) and , the second extractive distillation column (2 nd EDC) overhead stream is supplied to the first hydrodesulfurization unit (1 st GHT) or the dialkylation reaction unit (HDA) to avoid unnecessary separation, mixing and complex hydrogenation reaction. Since xylene is produced by supplying it to the second hydrodesulfurization unit (2nd GHT ) of In addition, in Example 2, the stream supplied to the C6 separation column (DeC6) increased, and it was confirmed that the amount of steam used was slightly increased than in Example 1.
[120]
In comparison, Comparative Example 1 did not produce styrene and xylene, but was not a comparison target as a process for producing only benzene, and thus comparative data on the total amount of steam used was not added. However, since the stream supplied to the first hydrodesulfurization unit (1 st GHT) is the largest at 176.4 ton/hr, the amount of hydrogen used in the first hydrodesulfurization unit (1 st GHT) is significantly large, and the life of the catalyst There is a problem in that the utility cost increases due to this decrease.
[121]
In Comparative Example 2, the benzene manufacturing process and the styrene manufacturing process were theoretically merged, and comparative data on the total amount of steam used was not added as a process in which xylene was not manufactured. However, in Comparative Example 2, compared to Example, the C7 separation column (DeC7) overhead stream containing C7 hydrocarbons is supplied to the first hydrodesulfurization unit (1 st GHT), and the second extractive distillation column (2 nd EDC ) ), unlike the embodiment in which xylene is produced by using the overheads stream separated from By inputting into the furnace, the stream supplied to the first hydrodesulfurization unit (1 st GHT) increases, thereby increasing the amount of hydrogen used, reducing the life of the catalyst, and increasing utility costs. In addition, since C7 and C8 hydrocarbons are introduced into the benzene manufacturing process, the C6 separation column (DeC6) for pre-separation in the benzene manufacturing process is not removed, so there is a problem in that the amount of steam is increased, and the dialkylation reaction unit (HDA) ), there is a problem in that the amount of hydrogen used in the dialkylation reaction unit (HDA) increases due to an increase in the stream supplied to the .
[122]
In addition, Comparative Example 3 was modified to a process for producing styrene as in the present application while theoretically merging the benzene production process and the styrene production process, and there is a problem in that the same problems as in Comparative Example 2 are still present. In addition, by separating xylene by additionally installing a xylene separation column (MX) under the C6 separation column (DeC6), energy consumption increases because C7 and C8 hydrocarbons have to undergo unnecessary separation, mixing, and re-separation processes. It can be seen that the total production of benzene, styrene and xylene has decreased.
Claims
[Claim 1]
the feed stream is fed to the C6 separation column, the top draw stream of the C6 separation column is fed to the first hydrodesulfurization unit, and the bottom draw stream is fed to the C7 separation column; feeding the C7 separation column overhead effluent stream to a dialkylation reaction unit and feeding the bottom effluent stream to a C8 separation column; separating benzene from the first hydrodesulfurization unit effluent stream and the dialkylation reaction unit effluent stream; removing the bottoms draw stream from the C8 separation column and feeding the top draw stream to a second extractive distillation column; and separating styrene from the second extractive distillation column bottoms draw stream and separating xylene from the top draw stream.
[Claim 2]
The method of claim 1 , wherein the feed stream comprises C5 hydrocarbons to C10 hydrocarbons.
[Claim 3]
The aromatic hydrocarbon of claim 1 , wherein the first hydrodesulphurizer effluent stream is fed to a first extractive distillation column, and benzene is separated from the first extractive distillation column bottoms effluent stream and the dialkylation reaction effluent stream. manufacturing method.
[Claim 4]
4. The method of claim 3, wherein the first extractive distillation column bottoms effluent stream and the dialkylation reaction effluent stream comprise C6 aromatic hydrocarbons.
[Claim 5]
4. The method of claim 3, wherein the first extractive distillation column bottoms effluent stream and the dialkylation reaction effluent stream form a mixed stream, and benzene is separated from the mixed stream.
[Claim 6]
The method of claim 1 , wherein the dialkylation reaction unit produces benzene by performing a dialkylation reaction of an aromatic hydrocarbon in the supplied stream.
[Claim 7]
The method of claim 1 , wherein the second extractive distillation column overheads stream is fed to a second hydrodesulfurization unit, and xylene is separated from the second hydrodesulfurization unit discharge stream.
[Claim 8]
The method of claim 7, wherein the second hydrodesulfurization unit includes a third hydrodesulfurization reactor, and the operating temperature of the third hydrodesulfurization reactor is 250°C to 350°C.
[Claim 9]
The process of claim 1 , wherein the C8 separation column bottoms effluent stream comprises C9+ hydrocarbons.
[Claim 10]
The process of claim 1 , wherein the second extractive distillation column overheads stream comprises C8 aromatic hydrocarbons and the bottoms draw stream comprises C8 vinyl aromatic hydrocarbons.
[Claim 11]
According to claim 1, wherein the first hydrodesulfurization unit feed stream comprising C5 hydrocarbons and C6 hydrocarbons is separately supplied, and the raw material stream supplied to the first hydrodesulfurization unit does not contain styrene. manufacturing method.