KR20200055472A - Method for Benzene, Toluene and Xylene from pyrolysis fuel oil - Google Patents

Abstract

Provided is a method for manufacturing benzene, toluene, and xylene, comprising: a first step of performing a selective hydrogenation reaction with the entire amount of pyrolyzed fuel oil, which is a by-product generated in a naphtha cracking center, as a raw material; and a second step of performing a hydrocracking reaction of the entire amount of reactants in the first step. According to the present invention, it is possible to solve the high heat of reaction generated during the hydrogenation reaction, suppress the rapid deactivation of a catalyst generated during the hydrocracking reaction with aromatic compounds with at least three rings, and secure an economic effect of not having to add a distillation process separately in order to reduce polycyclic aromatic compounds.

Description

Method for producing benzene, toluene, and xylene using pyrolysis fuel oil {Method for Benzene, Toluene and Xylene from pyrolysis fuel oil}

The present invention relates to a method for producing benzene, toluene, and xylene (BTX) having high added value from pyrolysis fuel oil (PFO) generated as a by-product of a naphtha cracking center (NCC), more specifically As a raw material, a method for producing benzene, toluene, and xylene, which is characterized in that it sequentially undergoes a selective hydrogenation reaction and a hydrolysis reaction by utilizing a pyrolysis fuel oil containing a polycyclic aromatic compound as a raw material.

Naphtha occupies a very important position in the petrochemical industry. The naphtha is a raw material for petrochemicals such as ethylene, propylene, butadiene, benzene, toluene, and xylene, as well as petrochemical products in a wide range of fields including synthetic resins, dyes, and pharmaceuticals. Because it makes. Although the demand for naphtha has steadily increased, manufacturing techniques using naphtha have limited use of only naphtha, a fraction of a narrow boiling range produced in the atmospheric distillation stage of crude oil, and increase in naphtha demand in the global market due to an increase in crude oil prices. There was an unresponsive problem.

In response to this, research has been conducted to apply naphtha as a raw material for the production of various aromatic products using by-products generated during the process of decomposition of a naphtha decomposition facility, which is a high-temperature pyrolysis process of 800 ° C or more as a raw material. Research is being conducted to use low-cost pyrolysis fuel oil as a by-product that is essentially generated at the bottom of the gasoline refinery tower.

For example, the benzene, toluene, and xylene contents are increased from the polycyclic aromatic hydrocarbons contained in the pyrolysis fuel oil by using catalysts carrying Group VIII and VIB metals on the composite zeolite support of zeolite beta and zeolite ZSM-5. A method for producing light aromatic hydrocarbons has been developed.

In addition, a method using a nano-sized zeolite catalyst in which zinc and lanthanum are impregnated, or a effluent oil obtained by distilling off oil containing a large amount of a bicyclic aromatic compound by distillation is hydrogenated and desulfurized / denitrified hydrogenated in the presence of a shape-selective catalyst. A method of manufacturing by removing one of the sulfur or nitrogen compounds in a decomposition reaction and converting it to one or more aromatic products of benzene, toluene and xylene was also studied.

However, the techniques using such a zeolite as a support have a problem in that the strength of the surface acid point of the zeolite is strong, so that a large amount of coke is generated during the hydrocracking reaction to block the acid point, thereby reducing the catalytic activity. The reaction of the catalyst had a problem in that the reaction was rapidly deactivated.

Thus, in the present invention, the whole product is used as a raw material in the pyrolysis fuel oil, which is a by-product of the naphtha cracking center, and the whole product is converted into a monocyclic aromatic compound through a selective hydrogenation reaction without any additional process, and then the hydrolysis reaction is performed on the reaction product. It is a manufacturing method that produces high value-added benzene, toluene, and xylene. While suppressing catalyst deactivation, benzene, toluene, and xylene that can improve the economic efficiency of the process without reducing polycyclic aromatic compounds having three or more rings It is to provide a manufacturing method.

Republic of Korea Registered Patent Publication No. 10-1815056 (Dec. 28, 2017) Republic of Korea Patent Publication No. 10-2018-0045594 (2018.05.04) Republic of Korea Patent Publication No. 10-2014-0068598 (2014.06.09)

The present invention was designed to solve the problems of the prior art described above, and the object of the present invention is to perform the selective hydrogenation reaction using the entire amount of pyrolysis fuel oil, which is a by-product of the naphtha cracking center, as a raw material, and of the reaction products of the above steps. Through the two steps of hydrogenation and decomposition reaction using the whole amount as a raw material, the polycyclic aromatic compound contained in the pyrolysis fuel oil is reduced and the high reaction heat problem arising from the hydrolysis reaction is solved without additional distillation process, and the catalyst is rapidly deactivated. It is to provide a method for producing benzene, toluene, and xylene that can suppress.

In order to achieve the above object, the present invention uses the pyrolysis fuel oil, which is a by-product generated in the naphtha cracking center, as a raw material, and performs the first step of selectively hydrogenating the whole raw material, and the reactant amount of the first step. It provides a benzene, toluene, xylene production method comprising a second step of the hydrocracking reaction.

Here, the pyrolysis fuel oil is a by-product that is fished at the naphtha cracking center, and the effect of the present invention can be achieved even when the total amount of the pyrolysis fuel oil is used without a separate separation step. It is preferable that the above aromatic compound contains 50% or more.

The selective hydrogenation of the first step uses NiMo / Al ₂ O ₃ or CoMo / Al ₂ O ₃ catalyst, and the second step of the hydrocracking reaction uses NiMo / zeolite or CoMo / zeolite catalyst. The first step and the second step of the invention are carried out in a fixed bed reactor.

In the present invention, the NiMo / Al ₂ O ₃ or CoMo / Al ₂ O ₃ catalyst of the first step can be added to the pyrolysis fuel oil to perform a selective hydrogenation reaction, and polycyclic aromatics having three or more rings through the above reaction The compound is converted to a monocyclic or bicyclic aromatic compound.

First step process: PFO + H ₂ → monocyclic or bicyclic aromatic compounds

In the present invention, the hydrolysis and decomposition reaction may be performed by adding the NiMo / zeolite or CoMo / zeolite catalyst of the second step to the entire amount of the first step reaction product, and the steps including benzene, toluene, and xylene may be performed through the reaction. Monocyclic aromatic compounds can be prepared.

Second step process: monocyclic or bicyclic aromatic compounds + H ₂ → BTX (benzene, toluene, xylene)

The zeolite in the second step uses any one of ZSM-5 zeolite, beta zeolite, mordenite zeolite, and Y zeolite.

In the second step process, the aromatic compound having 10 or more unconverted carbon atoms during the hydrocracking reaction is recycled to the hydrocracking reaction to convert to benzene, toluene, and xylene.

As described above, the method for producing benzene, toluene, and xylene of the present invention converts a large amount of polycyclic aromatic compounds contained in a pyrolysis fuel oil into a monocyclic or bicyclic aromatic compound through a selective hydrogenation reaction, and then catalyzes the hydrolysis reaction It relates to a method for producing benzene, toluene, and xylene having high added value without deactivation, and solves the problem of thermal runaway of high reaction heat generated during the hydrogenation reaction, and in particular, hydrogenation with 3 or more aromatic compounds During the decomposition reaction, the rapid deactivation of the catalyst was suppressed, and as a result, there was no need to add a distillation process separately to reduce the polycyclic aromatic compound of three or more rings. Toluene and xylene production methods can be provided.

1 is a graph showing the conversion efficiency of Example 1 of the present invention after the selective hydrogenation reaction of the PFO, followed by a hydrocracking reaction.
2 is a graph showing the conversion efficiency of Comparative Example 1 of the present invention in which the total amount of PFO is directly hydrolyzed.
3 is a graph showing the conversion efficiency of Comparative Example 2 of the present invention in which the total amount of PFO having a tricyclic aromatic of 5.2% is directly hydrolyzed.
4 is a graph showing the conversion efficiency of Comparative Example 3 of the present invention in which the total amount of PFO having tricyclic aromatics is 1.9% is directly hydrocracking.

Hereinafter, preferred embodiments of the present invention will be described in detail, but the scope of the present invention is not limited to the following embodiments.

The present invention, by using the thermal decomposition fuel oil, a by-product generated in the naphtha cracking center, as a raw material, by selectively hydrogenating the entire amount of the raw material to a polycyclic aromatic compound having three or more rings as an aromatic compound having one or two rings In the first step of converting, the second step of hydrocracking the entire amount of reactants in the first step may provide a method for producing a monocyclic aromatic compound including a method of producing benzene, toluene, and xylene.

The pyrolysis fuel oil used in the present invention includes the composition of the aromatic compound for each ring number as shown in Table 1 below.

PFO 9%
heavy cut 25%
heavy cut 38%
heavy cut 2 or less compounds 82.4 85.2 94.8 98.1 Tricyclic compound 15.0 14.3 4.1 1.9 4 or more compounds 2.26 0.5 1.1

Note: 9% Heavy cut is PFO with 9% high boiling point compound removed

The present invention uses the entire amount of pyrolysis fuel oil, which is a by-product essential in the naphtha cracking center, as a raw material, and does not require a separate reduction or separation process.

The selective hydrogenation reaction in the first step of the present invention uses the entire amount of the pyrolysis fuel oil as a raw material, and a polycyclic aromatic having three or more rings using a NiMo / Al ₂ O ₃ or CoMo / Al ₂ O ₃ catalyst. Selective hydrogenation reaction of the compound with hydrogen at a temperature of 250 to 400 ° C. and a pressure of 30 to 100 barg produces a monocyclic or bicyclic aromatic compound.

The hydrocracking reaction in the second step of the present invention uses the entire amount of the product of the selective hydrogenation reaction in the first step as a raw material, and uses a NiMo / zeolite or CoMo / zeolite catalyst to monocyclic or bicyclic aromatic As a hydrocracking reaction in which the compound is reacted with hydrogen at a temperature of 250 to 450 ° C. and a pressure of 30 to 100 barg, a monocyclic aromatic compound containing benzene, toluene, and xylene is produced.

The zeolite in the second step of the present invention may be any one of ZSM-5 zeolite, beta zeolite, mordenite zeolite or Y zeolite.

In the above two kinds of steps, a process of adding a sulfur compound such as DMDS may be added to maintain catalytic activity if necessary.

As the product of the hydrolysis reaction in the second step, unconverted oil contained in an aromatic compound including benzene, toluene, and xylene may be added to the process of circulating the above process.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1]

According to the method of the present invention, after converting the concentration of the compound having three or more rings contained in the pyrolysis fuel oil to 5% or less through the selective hydrogenation reaction of the first step using the total amount of the pyrolysis fuel oil without a separate separation step, A monocyclic aromatic compound including benzene, toluene, and xylene was prepared by introducing the entire amount of the reaction product into a hydrocracking reactor in the second step according to the method of the present invention to perform a hydrocracking reaction.

NiMo / Al ₂ O ₃ was used as a catalyst in the step 1 selective hydrogenation, and reaction conditions were a reaction temperature of 280 degrees, a reaction pressure of 80 barg, a hydrogen / hydrocarbon ratio of 800, and a PFO LHSV of 0.5 hr ⁻¹ . In the two-step hydrocracking step, CoMo / Beta was used as a catalyst, the reaction temperature was 300 degrees, the reaction pressure was 80 barg, the hydrogen / hydrocarbon ratio 800, and the hydrogenated PFO LHSV 0.5 hr ^{-1 was} .

By converting a polycyclic aromatic compound having 3 or more rings into an aromatic compound having 2 or less rings, the deactivation of the catalyst was drastically reduced, and the possibility of thermal runaway occurred by dispersing the reaction heat due to hydrogenation into a reactor in 2 stages. Was minimized.

FIG. 1 is a graph showing the results of experiments of a hydrocracking reaction after a selective hydrogenation reaction using pyrolysis fuel oil as a feed according to Example 1 above. According to Figure 1, it can be seen that the activation of the hydrocracking catalyst does not drop and remains constant for more than 7 days.

[Comparative Example 1]

The entire amount of pyrolysis fuel oil was introduced to the hydrocracking reactor to perform a hydrocracking reaction, but a rapid deactivation of the hydrocracking catalyst occurred due to a polycyclic aromatic compound having 3 or more rings, so long-term operation of more than 6 months is impossible In the case of the hydrocracking reaction, there was a fear of thermal runaway due to the rapid temperature rise.

※ Conversion rate (% by weight): The conversion rate of two or more aromatic compounds.

※ A1 yield (weight%): Yield of the monocyclic aromatic compound in the reaction product.

※ C1-C4 yield (% by weight): The yield of hydrocarbon compounds up to 1-4 carbons in the reaction product.

In the hydrocracking step, CoMo / Beta was used as the catalyst, the reaction temperature was 280 degrees, the reaction pressure was 80 barg, the hydrogen / hydrocarbon ratio was 2,500, and the PFO LHSV was 0.1 hr ^-1 .

Figure 2 is a graph showing the conversion efficiency results through a hydrocracking reaction experiment using the total amount of pyrolysis fuel oil as a feed. As shown in FIG. 2, it can be seen that the activation efficiency of the hydrocracking reaction catalyst decreases from about 20 hours.

[Comparative Example 2]

The high boiling point compound contained in the pyrolysis fuel oil was removed by 25%, and the feed having a concentration of 5.2% or more of polycyclic aromatic compounds having three or more rings was subjected to hydrocracking reaction. In this case, the deactivation of the catalyst was reduced compared to the case where the entire amount of pyrolysis fuel oil was subjected to a hydrocracking reaction, but it was not possible to completely suppress the deactivation.

In the hydrocracking step, CoMo / Beta was used as the catalyst, the reaction temperature was 280 degrees, the reaction pressure was 80 barg, the hydrogen / hydrocarbon ratio was 2,500, and the PFO LHSV was 0.1 hr ^-1 .

3 is a graph showing the conversion efficiency of the catalyst through a hydrocracking catalyst used as a feed by removing 25% of the high boiling point compound contained in the pyrolysis fuel oil. According to FIG. 3, the deactivation of the hydrocracking catalyst was relatively reduced, but still decreased, rather than the result in Comparative Example 1, and the complete deactivation of the hydrocracking catalyst was not suppressed.

[Comparative Example 3]

The total amount of pyrolysis fuel oil was distilled to minimize the concentration of polycyclic aromatic compounds having 3 or more rings to 5% or less, followed by a hydrocracking reaction. In this case, the rapid deactivation of the hydrocracking catalyst could be reduced, but the process efficiency and economic efficiency were lowered by the addition of a distillation process.

In the hydrocracking step, CoMo / Beta was used as the catalyst, the reaction temperature was 280 degrees, the reaction pressure was 80 barg, the hydrogen / hydrocarbon ratio was 2,500, and the PFO LHSV was 0.1 hr ^-1 .

4 is a graph showing the results of experiments of activation of the hydrocracking catalyst used as a feed by removing 38% of the high boiling point compound contained in the pyrolysis fuel oil through distillation. When compared with Comparative Examples 1 and 2, it was confirmed that the rapid deactivation of the hydrocracking catalyst was reduced to the level of the Examples.

Claims (7)

Pyrolysis fuel oil, a by-product generated in the naphtha cracking center, is a raw material containing 50% or more of two or more aromatic compounds, and the first step of selectively hydrogenating the whole amount of the above raw materials, and the entire amount of reactants in the first step A second step of performing a hydrocracking reaction; The benzene, toluene, xylene production method comprising a.
The method of claim 1, wherein the pyrolysis fuel oil is a by-product of the pyrolysis fuel oil containing 50% or more of two or more aromatic compounds without a separate separation step, as a by-product of the naphtha cracking center, characterized in that, Method of manufacturing toluene and xylene. The method for preparing benzene, toluene, and xylene according to claim 1, wherein the selective hydrogenation reaction of the first step uses a NiMo / Al ₂ O ₃ or CoMo / Al ₂ O ₃ catalyst. The method for preparing benzene, toluene, and xylene according to claim 1, wherein the hydrocracking reaction in the second step uses a NiMo / zeolite or CoMo / zeolite catalyst. The method of claim 4, wherein the zeolite is one of ZSM-5 zeolite, beta zeolite, mordenite zeolite, and Y zeolite. The method according to claim 1, wherein the first step is a selective hydrogenation reaction under a temperature of 250 to 400 ° C. and 30 to 100 barg. The method of claim 1, wherein the second step is a benzene, toluene, and xylene production method, which is a hydrocracking reaction at a temperature of 250 to 450 ° C and 30 to 100 barg.

Images