KR102188532B1 - Molecular size-selective hydrocracking catalysts for the production of light aromatic hydrocarbons from polycyclic aromatic hydrocarbons - Google Patents

Abstract

The present invention relates to a catalyst for molecular size-selective hydrocracking reaction for the production of light aromatic hydrocarbons in the range of C ₆ -C ₉ with increased BTX content from polycyclic aromatic hydrocarbons, a method for preparing the same, and a C ₆ -C ₉ range with increased BTX content using the same. It relates to a method for producing a light aromatic hydrocarbon, and more particularly, in a composite zeolite carrier of zeolite beta, zeolite Y containing mesopores, and zeolite ZSM-5, Mo alone or a group VIB metal Mo and a group VIIIB metal By using a catalyst supported with phosphorus Co, light aromatic hydrocarbons in the range of C ₆ -C ₉ with increased BTX content can be obtained in high yield from oils of high polycyclic aromatic hydrocarbons such as bicyclic aromatics and oils of petrochemical processes. You can achieve the effect.

Description

Molecular size-selective hydrocracking catalysts for the production of light aromatic hydrocarbons from polycyclic aromatic hydrocarbons}

The present invention relates to a catalyst for molecular size-selective hydrocracking reaction for the production of high valued light aromatic hydrocarbons from fractions with a high content of polycyclic aromatics among by-products of oil refining and petrochemical processes, and more particularly, of the FCC process of a hydrogenated refinery. Provides a catalyst for molecular size-selective hydrocracking reaction that produces high-value light aromatic hydrocarbons in high yield from Light Cycle Oil (LCO), a by-product, and uses them to benzene (B), toluene (T) and xylene (X). It relates to a technology for producing a light aromatic hydrocarbon in the range of C ₆ ~ C ₉ having a high (BTX) content.

In oil refining and petrochemical processes, many polycyclic aromatic hydrocarbons having a high content of naphthalene and alkyl-naphthalene are being produced. Representative examples include PFO (Pyrolysis Fuel Oil) in the Naphtha Cracking Center (NCC) process, C ₁₀ ⁺ heavy aromatics in the Para-xylene process, and Light Cycle Oil (LCO) in the Fluid Catalytic Cracker (FCC) process. Among them, FCC LCO, which has the most by-products, has a boiling point range of diesel, but has a high content of aromatics, sulfur and nitrogen and a low cetane value, so the amount used as diesel is very limited. Therefore, most of FCC LCO is used to adjust the viscosity of heavy fuel oil for low-value ships, and in the long term, the viscosity of diesel and heavy fuel oil is due to the strengthening of environmental regulations, the increase in eco-friendly vehicles and eco-friendly ships, and the increased use of clean fuel oil and power generation systems required for this. The amount of LCO used for control is also expected to decrease significantly. Therefore, there is a need to develop a catalytic process capable of converting polycyclic aromatic hydrocarbons including FCC LCO into high value products. In particular, as a way to add polycyclic aromatic hydrocarbons with a high content of naphthalenes such as FCC LCO, 1) diesel with a high cetane number (CN, Cetane Number) or 2) C ₆ -C containing BTX (Benzene, Toluene, Xylenes) Two options for conversion to light aromatic hydrocarbons in the ₉ range can be considered. The present invention relates to a catalyst required for a process capable of converting a polycyclic aromatic hydrocarbon into a high-value light aromatic hydrocarbon in consideration of the market demand and economy described above. The reaction route for preparing a light aromatic having a high BTX content from a polycyclic aromatic hydrocarbon is shown in [Scheme 1] below, for example, using (alkyl) naphthalenes (Alkyl-Naphthalenes, hereinafter referred to as "naphthalenes").

[Scheme 1]

In order to convert naphthalenes into high-added light aromatic hydrocarbons including BTX, as shown in [Scheme 1] above, only one benzene ring among two benzene rings of naphthalenes is selectively hydrogenated and naphthene ( naphthene) is converted to alkyl-tetralins (hereinafter referred to as "tetralins") having a ring, and the naphthenic ring of tetralins is decomposed by continuous hydrocracking (HDC, Hydrocracking) BTX can be generated.

Meanwhile, reactions between naphthalenes ↔ tetralins and tetralins ↔ decalins (alkyl-decalins, alkyl-decalins, hereinafter referred to as "decalins") in [Reaction Scheme 1] are all reversible reactions determined by thermodynamic equilibrium relations. And is activated by a metal catalyst. The hydrogenation reaction in which tetralins are generated from naphthalenes is a strong exothermic reaction in which the total number of moles decreases. The higher the pressure and the lower the reaction temperature, the higher the equilibrium conversion rate of naphthalenes. On the other hand, when the reaction temperature is high and the hydrogen pressure is low, the dehydrogenation reaction in which tetralins are converted back to naphthalenes is dominant and the conversion rate of naphthalenes decreases. In the hydrogenation reaction in which decalins are generated from tetralins, the higher the pressure and the lower the temperature, the higher the equilibrium conversion rate.

In [Scheme 1], since hydrocracking reaction (HDC) is generally carried out at high temperature and high pressure, tetralins can be re-converted to naphthalenes by dehydrogenation. In this case, the yield of light aromatic hydrocarbons including BTX is Becomes lower. In addition, if the hydrogenation activity of the hydrocracking catalyst is excessively high and the benzene ring of tetralins is further hydrogenated to generate a lot of decalin, the decalin is decomposed into LPG and naphtha by hydrocracking (HDC). As a result, the yield of light aromatic hydrocarbons including the final BTX decreases and hydrogen consumption increases.

Therefore, in order to obtain the maximum yield of light aromatic hydrocarbons containing high-value BTX, reconversion of tetralins to naphthalenes in the hydrocracking reaction of tetralins (dehydrogenation reaction) and tetralins become decalins. Hydrogenation reaction should be suppressed. To this end, there is a need for a hydrocracking catalyst that maximizes the yield of light aromatic hydrocarbons including BTX by appropriately controlling the hydrogenation function of the hydrocracking reaction catalyst to minimize the generation of LPG and naphtha.

However, in general, when a catalyst for hydrocracking reaction is used, for example, hydrocracking reaction of tetralin is C ₉ aromatics (trimethylbenzenes; 1,2,4-trimethylbenzene, 1,2,5-trimethylbenzene and 1, Various alkyl-benzenes in the C ₈ -C ₁₀ range including 3,5-trimethylbenzene, propylbenzene, ethyltoluene, etc.), ethylbenzene, butylbenzene, methylpropylbenzene, and ethylxylene (Alkyl-Benzenes, hereinafter "Alkyl-Bz") is produced in high yield, and the contents of C ₉ aromatic and ethylbenzene are particularly high among alkyl-benzenes. Here, the alkyl-benzenes can be converted to BTX in high yield in the transalkylation/dealkylation process that has been commercialized in the past, so it is considered as a high added light aromatic hydrocarbon along with BTX. Therefore, as described above, the hydrogenation function of the catalyst for hydrocracking reaction is properly adjusted and various alkyl-benzenes in the range of C ₈ -C ₁₀ are converted into light aromatic hydrocarbons having a high content of BTX through dealkylation reaction. By appropriately controlling the decomposition function of zeolite, it should be possible to obtain a high-added light aromatic hydrocarbon containing final BTX and Alkyl-Bz aromatic in high yield.

In addition, FCC LCO contains a large amount of tricyclic or more aromatic compounds (eg, Anthracene and Penanthrene) having a large molecular size. In order for these to be converted into high-added light aromatic hydrocarbons including BTX and Alkyl-Bz through a hydrocracking reaction, it is required to appropriately control the pore size of the zeolite.

Therefore, the present inventors exhibit the above-described characteristics in order to obtain light aromatic hydrocarbons containing high added BTX and Alkyl-Bz from LCO (Light Cycle Oil) of the hydrotreated FCC (Fluid Catalytic Cracker) process in high yield. Focusing on the necessity of developing a new catalyst, the present invention was completed.

Patent Document 1. Korean Laid-Open Patent Publication No. 10-2013-0055047 Patent Document 2. Korean Laid-Open Patent Publication No. 10-2015-0116412

The present invention has been conceived in consideration of the above problems, it is an object of the present invention are C ₆ high value of the BTX content is increased from a polycyclic aromatic hydrocarbon included in the Light Cycle Oil (LCO) a by-product of oil refining and petrochemical process -C ₉ intended to provide a method of manufacturing a light aromatic hydrocarbon molecule for the manufacture size-selective hydrogenolysis catalysts, their preparation and in the high value-added increase BTX content using this C ₆ -C ₉ aromatic hydrocarbon environment.

One aspect of the present invention for achieving the above object is (i) zeolite beta having a 12-MR (membered ring) pore size, zeolite Y having a 12-MR pore size and mesopores of 2 to 50 nm, and A composite zeolite of zeolite ZSM-5 having a 10-MR pore size; And (ii) a group VIB metal, or a mixed metal of a group VIB metal and a group VIIIB metal; it relates to a catalyst for a molecular size-selective hydrocracking reaction.

Another aspect of the present invention is (a) dissolving a group VIB metal precursor or a mixed metal precursor of group VIB and group VIIIB in distilled water to prepare an aqueous metal precursor solution; (b) impregnating the composite zeolite of zeolite beta, zeolite Y and zeolite ZSM-5 with the aqueous metal precursor solution obtained in step (a); And (c) drying the metal-supported composite zeolite obtained in step (b), and then calcining in an oven flowing with oxygen to obtain a composite zeolite-based catalyst containing metal together; It relates to a method for producing a reaction catalyst.

Another aspect of the present invention is a method for producing a light aromatic hydrocarbon in the range of C ₆ -C ₉ from a polycyclic aromatic hydrocarbon using the catalyst for molecular size selective hydrocracking reaction according to the present invention, in a reactor, (1) the Drying the hydrocracking reaction catalyst; (2) after raising the temperature of the reactor to 400 to 500° C., the pressure is adjusted to 400 to 1500 psig, and sulfurizing the hydrocracking reaction catalyst in a gas stream containing hydrogen; (3) After lowering the reactor temperature to 120° C. or less, the pressure is adjusted to 500 to 1600 psig, and the hydrogen flow rate is adjusted to 30 to 100 cc/min·g-cat; (4) flowing a polycyclic aromatic hydrocarbon at a flow rate of 0.01 to 3.3 cc/min·g-cat; And (5) raising the reactor temperature to 350 to 450° C. to react, and then recovering the reaction liquid product in a gas/liquid separator; characterized in that it comprises a C ₆ -C ₉ range from a polycyclic aromatic hydrocarbon. It relates to a method for producing light aromatic hydrocarbons.

According to the present invention, molecular size-selective hydrocracking reaction for the production of C ₆ -C ₉ light aromatic hydrocarbons with increased BTX content from polycyclic aromatic hydrocarbons contained in Light Cycle Oil (LCO), a by-product of oil refining and petrochemical processes A catalyst can be prepared, and through this, a C ₆ -C ₉ light aromatic hydrocarbon having an increased BTX content can be produced in high yield.

1 is a diagram illustrating a molecular size-selective hydrocracking function for each zeolite having different acidity and pore size included in a catalyst for hydrocracking in a hydrocracking reaction of LCO treated with hydrogenation according to embodiments of the present invention.
FIG. 2 is a result of hydrocracking LCO treated with hydrogenation using catalysts 1, 2 and 5 for hydrocracking reactions prepared from Preparation Example 2, respectively, in Comparative Examples 2, 3 and 4 of the present invention, ZSM- 5 It is a graph showing the yield of BTX and Alkyl-Bz according to the content [reaction temperature 400 ℃].
3 is a result of hydrocracking LCO treated with hydrogenation using catalysts 6, 7 and 2 for hydrocracking reactions prepared from Preparation Example 2 in Examples 1 to 2 and Comparative Example 1 of the present invention, respectively, It is a graph showing the yield of BTX, BTX+Alkyl-Bz and C ₁₁ ⁺ aromatic according to the content of zeolite Y having mesopores [reaction temperature 400° C.].

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

In the present specification, the term "hydrocracking reaction of polycyclic aromatic hydrocarbons" is defined as hydrocracking the leadene ring of an aromatic compound having a leadene ring produced by adding hydrogen to a reaction product containing a polycyclic aromatic hydrocarbon in the presence of a hydrotreating catalyst. do. When naphthalene is described as an example among polycyclic aromatic hydrocarbons, as shown in the following [Reaction Scheme 2], when hydrogen is added in the presence of a hydrotreating catalyst, naphthalene is selectively selected from two benzene rings constituting naphthalene. It is hydrogenated to produce tetralin. Thereafter, as hydrogen is added in the presence of a continuous hydrocracking reaction catalyst, the leadene ring of tetralin is opened and decomposed, thereby finally producing a light aromatic hydrocarbon including high added BTX and Alkyl-Bz.

[Scheme 2]

Converting polycyclic aromatic hydrocarbons having two or more benzene rings such as naphthalene and alkyl-naphthalene contained in by-products of refinery and petrochemical processes into high-value light aromatic hydrocarbons including BTX using conventional catalysts for hydrocracking reactions Although the techniques for this have been suggested, not only alkyl-benzenes in the C ₈ -C ₁₀ range having 1-ring aromatics other than light aromatic hydrocarbons including BTX, but also 2-ring aromatic hydrocarbons of C ₁₁ ⁺ having a large molecular size in high yield. There is a problem that the yield of C ₆ -C ₉ light aromatic hydrocarbons including final BTX is not high. Therefore, the catalyst for hydrocracking reaction according to the present invention has excellent activity to convert alkyl-benzenes other than BTX and 2-ring aromatic hydrocarbons of C ₁₁ ⁺ having a large molecular size to BTX, so that the final high-value BTX and Alkyl-Bz are It can solve the problem that the yield of is not high. In particular, the catalyst for the hydrocracking reaction according to the present invention is the reconversion of tetralins to naphthalenes in which only one of the two benzene rings of bicyclic aromatic hydrocarbons such as naphthalenes having a high content among polycyclic aromatic hydrocarbons is selectively hydrogenated. By suppressing the hydrogenation reaction to and decalin (see Scheme 2 above), a C ₆ -C ₉ light aromatic hydrocarbon including the final high-added BTX and Alkyl-Bz can be obtained in high yield.

Here, the refining and petrochemical process by-products include Light Cycle Oil (LCO) of the FCC process and C ₁₀ ⁺ of the para-xylene process. There are heavy aromatics and PFO (Pyrolysis Fuel Oil) of the Naphtha Cracking Center (NCC) process, and the by-products include bicyclic aromatic hydrocarbons such as naphthalene and methyl-naphthalene, and anthracene, methyl-anthracene, and penan. A large amount of tricyclic aromatic hydrocarbons such as penanthrene are contained, and the light aromatic hydrocarbon is a hydrocarbon having 6-9 carbon atoms including benzene, toluene, and xylene (BTX) and benzene substituted with an alkyl group.

One aspect of the present invention is (i) a zeolite beta having a 12-MR (membered ring) pore size, a 12-MR (membered ring) pore size, and a zeolite Y having a mesopores of 2 to 50 nm having a larger pore size, and A composite zeolite of zeolite ZSM-5 having a 10-MR pore size; And (ii) a Group VIB metal, or a mixed metal of a Group VIB metal and a Group VIIIB metal; comprising, a catalyst for a molecular size-selective hydrocracking reaction, wherein the catalyst for a molecular size-selective hydrocracking reaction is pseudo- Boehmite (Pseudo Boehmite) may be further included.

In general, zeolite has pores of micro (<2 nm) size, and the 12-MR pore size ranges from 0.6 to 0.7 nm, and the 10-MR pore size ranges from 0.5 to 0.6 nm. That is, since it has a pore size that is about the size of a benzene molecule, it exhibits shape-selective catalysis.

In particular, the catalyst for molecular size-selective hydrocracking reaction according to the present invention is different from the case of using zeolite beta, zeolite ZSM-5, or zeolite Y as a zeolite component, respectively, zeolite beta and zeolite ZSM- having a smaller pore size. By using a composite zeolite in which zeolite Y, which has a larger pore size than that of 5 and zeolite beta, and has mesopores inside the crystal, is used, various kinds of alkyl-benzenes in the range of C ₈ -C _{10 in} addition to BTX can be used in dealkylation reactions. By this, it was confirmed that not only the conversion to BTX was promoted, but also the unconverted C ₁₁ ⁺ aromatic compound having a large molecular size was smoothly converted, and finally, the yield of high added BTX and Alkyl-Bz was significantly increased. (See FIGS. 1 to 3).

In particular, although not explicitly described in the following Examples or Comparative Examples, zeolite beta having 12-MR (membered ring) pore size as the composite zeolite, 12-MR pore size and mesopores of 2 to 50 nm In the case of including both zeolite Y and zeolite ZSM-5 having a 10-MR pore size, destruction of the composite zeolite, changes in external roughness, and even after carrying out the hydrocracking reaction according to Experimental Example 2 300 times at a high temperature of 500°C or higher, and It was confirmed through a scanning electron microscope (SEM) that no defects were observed, and that the metal catalyst was uniformly supported on the entire surface of the composite zeolite without any aggregation and loss of metal catalysts. However, the composite zeolite It does not contain any one of zeolite beta having 12-MR (membered ring) pore size, zeolite Y having 12-MR pore size and mesopores of 2 to 50 nm, and zeolite ZSM-5 having 10-MR pore size If not, it was confirmed that, as a result of the same hydrocracking reaction as described above, not only the destruction of the composite zeolite, changes in external roughness, or defects were observed, but also the loss and aggregation of the metal supported on the surface of the composite zeolite occurred remarkably.

According to one embodiment, the zeolite beta is a form consisting of SiO ₂ and Al ₂ O ₃ in a molar ratio of 50 to 90:1, a specific surface area of 550 to 750 m ² /g, and a total pore volume of 0.2 to 0.4 cc /g, the average pore size is 1 nm or less; The zeolite Y is a form consisting of SiO ₂ and Al ₂ O ₃ in a molar ratio of 10 to 50:1, a specific surface area of 650 to 850 m ² /g, a total pore volume of 0.4 to 0.6 cc/g, and an average pore It contains two kinds of pores of size 2 to 10 nm and 1 nm or less; The zeolite ZSM-5 has SiO ₂ and Al ₂ O ₃ in a molar ratio of 60 to 100:1, a specific surface area of 300 to 500 m ² /g, and a total pore volume of 0.01 to 0.3 cc/g, The average pore size may be 1 nm or less.

In particular, when the size of the mesopores of the zeolite Y having mesopores is less than 2 nm, the diffusion resistance of the large molecular size C ₁₁ ⁺ aromatics into the zeolite pores is large, and the conversion rate of the decomposition reaction of C ₁₁ ⁺ aromatics is low, so BTX and The improvement of the yield of Alkyl-Bz is limited, and the non-selective decomposition reaction proceeds excessively even when the size of the mesopores of zeolite Y with mesopores exceeds 10 nm, resulting in the yield of gaseous gas products such as LPG at room temperature. It increases and the yield of the liquid product decreases, consequently lowering the final BTX yield and increasing the amount of hydrogen consumption.

According to another embodiment, the group VIB metal may be Mo, the group VIIIB metal may be Co, and the group VIB and group VIIIB metals are preferably in the form of sulfides.

According to another embodiment, the content of the composite zeolite may be 50 to 95% by weight based on the total weight of the hydrocracking reaction catalyst, and it was confirmed that the tetralin conversion rate was significantly lowered when it was outside the above range.

According to another embodiment, with respect to the total weight of the composite zeolite, the zeolite beta may include 65 to 90 wt%, the zeolite Y 1 to 20 wt%, and the zeolite ZSM-5 1 to 30 wt%.

When the content of zeolite beta is less than 65% by weight, a problem may occur in which the reverse reaction of reconversion to naphthalene occurs due to the dehydrogenation of tetralin, and when the content of zeolite beta exceeds 90% by weight Since the decomposition reaction proceeds excessively, the yield of the gaseous product as a gas at room temperature such as LPG increases and the yield of the liquid product decreases. As a result, there is a problem that the final BTX yield decreases and the hydrogen consumption increases.

When the content of the zeolite ZSM-5 is less than 1% by weight, the conversion rate of alkyl-benzenes other than BTX to BTX is low, so the improvement of the total BTX yield is limited, and the ZSM-5 content may exceed 30% by weight. In this case, the decomposition reaction proceeds excessively, resulting in an increase in the yield of a gaseous gas product such as LPG at room temperature and a decrease in the yield of the liquid product, resulting in a decrease in the final BTX yield and an increase in hydrogen consumption.

When the content of zeolite Y having mesopores is less than 1% by weight, the conversion rate of C ₁₁ ⁺ aromatic having a large molecular size to BTX and Alkyl-Bz is low, so that the improvement in the yield of total BTX and Alkyl-Bz is limited. , When the content of zeolite Y having mesopores exceeds 20% by weight, the non-selective decomposition reaction proceeds excessively, resulting in an increase in the yield of a gaseous gas product such as LPG at room temperature and a decrease in the yield of the liquid product. There is a problem that the final BTX yield is lowered and the hydrogen consumption is increased.

According to another embodiment, the composite zeolite may be in a form in which SiO ₂ and Al ₂ O ₃ have a molar ratio of 10-100:1, and when the molar ratio is lower than the lower limit, the acidity of the zeolite is high and the decomposition reaction is performed. Excessively, gas (LPG) and naphtha production amount increases, the yield of light aromatic hydrocarbons including BTX decreases, and hydrogen consumption increases. On the other hand, when the molar ratio exceeds the upper limit, the acidity of zeolite is low and a high reaction temperature is required. Accordingly, the reverse reaction of reaction route 1 of [Scheme 2] (reconversion to naphthalene by dehydrogenation of tetralin) ) Is increased, there is a problem that the life of the catalyst is shortened due to acceleration of coke deposition.

According to another embodiment, the Mo content may be 5-20 wt% based on the total weight of the hydrocracking reaction catalyst, and the Co content may be 0-10 wt% based on the total weight of the hydrocracking reaction catalyst. . When the metal supported on the composite zeolite is contained below the lower limit of the above range, the hydrogenation function is reduced due to a decrease in the number of active points of hydrogenation of the catalyst, and thus tetralin is reconverted to naphthalene through a dehydrogenation reaction, or C ₁₀ ⁺ heavy aromatic There is a problem that the amount of BTX in the liquid product increases due to the increase in the amount of production, and the stability of the hydrocracking catalyst is lowered due to coke deposition. After conversion, it is decomposed to increase the production of LPG and Naphtha, resulting in a decrease in the yield of the liquid product and final BTX, and an increase in hydrogen consumption (refer to Scheme 2).

In particular, when the catalyst for hydrocracking reaction according to the present invention does not contain any one of zeolite beta, zeolite ZSM-5, zeolite Y and VIB group metals having mesopores, a liquid product compared to the case of including all of the above configurations. It was confirmed that the selectivity of BTX and the yield of BTX were significantly reduced.

Another aspect of the present invention is (a) dissolving a group VIB metal precursor or a mixed metal precursor of group VIB and group VIIIB in distilled water to prepare an aqueous metal precursor solution; (b) impregnating the composite zeolite of zeolite beta, zeolite Y and zeolite ZSM-5 with the aqueous metal precursor solution obtained in step (a); And (c) drying the metal-supported composite zeolite obtained in step (b), and then calcining in an oven flowing with oxygen to obtain a composite zeolite-based catalyst containing metal together; It relates to a method for producing a reaction catalyst.

According to an embodiment, the drying in step (c) is performed at room temperature for 1 to 10 hours, preferably 2 to 8 hours, more preferably 4 to 7 hours, and then 1 to 20 at 60 to 100°C. It is carried out for an hour, preferably 5 to 18 hours, more preferably 8 to 14 hours, and the firing of step (c) is 8 to 12° C./min from room temperature to the first heat treatment temperature between 100 to 300° C. A first heat treatment step of raising the temperature to; And a second heat treatment step of raising the temperature from the first heat treatment temperature to a second heat treatment temperature between 400 and 600° C. at 1 to 7° C./min.

Another aspect of the present invention is a method for producing a light aromatic hydrocarbon in the range of C ₆ -C ₉ from a polycyclic aromatic hydrocarbon using the molecular size selective hydrocracking reaction catalyst according to the present invention, in a reactor, (1) the hydrogenation Drying the catalyst for the decomposition reaction; (2) after raising the temperature of the reactor to 400 to 500° C., the pressure is adjusted to 400 to 1500 psig, and sulfurizing the hydrocracking reaction catalyst in a gas stream containing hydrogen; (3) After lowering the reactor temperature to 120° C. or less, the pressure is adjusted to 500 to 1600 psig, and the hydrogen flow rate is adjusted to 30 to 100 cc/min·g-cat; (4) flowing a polycyclic aromatic hydrocarbon at a flow rate of 0.01 to 3.3 cc/min·g-cat; And (5) raising the reactor temperature to 350 to 450° C. to react, and then recovering the reaction liquid product in a gas/liquid separator; characterized in that it comprises a C ₆ -C ₉ range from a polycyclic aromatic hydrocarbon. If directed to a method of producing aromatic hydrocarbons, the C ₆ ring 1 and bicyclic polycyclic aromatic hydrocarbons BTX content is the increased C ₆ -C ₉ aromatic light from such as aromatic through the manufacturing method of the light -C ₉ aromatic hydrocarbons range The effect of obtaining a hydrocarbon in high yield can be obtained.

According to one embodiment, in the polycyclic aromatic hydrocarbon, the sum of the monocyclic and bicyclic aromatic hydrocarbon contents may be 50 to 95% by weight based on the total weight of the polycyclic aromatic hydrocarbon.

In particular, although not explicitly described in the following Examples or Comparative Examples, etc., in the catalyst for molecular size selective hydrocracking reaction according to the present invention, for various kinds of supported metals, whether pseudo-boehmite is included, supported metals Sulfidation treatment, content of composite zeolite, content of zeolite beta, content of zeolite ZSM-5, content of zeolite Y, average size of mesopores of zeolite Y, molar ratio of SiO ₂ and Al ₂ O ₃ to SiO ₂ and Al ₂ O ₃ of the composite zeolite and supported After carrying out the hydrocracking reaction according to Experimental Example 2 300 times using a catalyst for a molecular size-selective hydrocracking reaction with a changed metal content, it was confirmed whether the metal supported on the catalyst was lost through scanning electron microscope (SEM) analysis. I did.

As a result, unlike other types of supported metals, other conditions and other numerical ranges, (i) the supported metal is Mo, (ii) further includes Pseudo Boehmite, and (iii) the supported metal Is in the form of a sulfide, (iv) the content of the composite zeolite is 50 to 95% by weight based on the total weight of the hydrocracking reaction catalyst, (v) the content of zeolite beta is 65 to 90% by weight based on the total weight of the composite zeolite. , (Vi) The content of zeolite ZSM-5 is 1 to 30% by weight based on the total weight of the composite zeolite, (vii) the content of zeolite Y is 1 to 20% by weight based on the total weight of the composite zeolite, (viii) The average mesopores size of zeolite Y is 2 to 10 nm, (ix) the composite zeolite is in the form of SiO ₂ and Al ₂ O ₃ in a molar ratio of 10-100:1, and (x) Mo content is the hydrocracking reaction. When all the conditions of 5-20% by weight based on the total weight of the catalyst were satisfied, no loss of metal supported on the catalyst for hydrocracking was observed even after 300 hydrocracking reactions, but any one of the above conditions was satisfied. If not, it was confirmed that the supported metal was remarkably lost in the catalyst for hydrocracking reaction after carrying out hydrocracking 300 times.

Hereinafter, manufacturing examples and examples according to the present invention will be described in detail together with the accompanying drawings.

Preparation Example 1: Preparation of HDC reactant hydrogenated LCO (HDT-LCO)

As a reactant of the hydrocracking (HDC) reaction used in the Examples and Comparative Examples of the present invention, LCO is hydrogenated using a commercial hydrotreating (HDT) catalyst (Vacuum Gasoil HDS catalyst). HDT-LCO) was used, and two HDT-LCOs were prepared as follows.

(1) HDT-LCO 1: HDT-LCO 1 is the LCO collected from FCC (Fluid Catalytic Cracker) process as shown in [Table 1], WHSV = 0.7 h ^-1 , pressure = 60 bar, reaction temperature = 350- It shows the product obtained by hydrogenation at 358 °C and H ₂ /LCO = 2600 mL / mL conditions.

(2) HDT-LCO 2: HDT-LCO 2 is the LCO obtained from FCC (Fluid Catalytic Cracker) process, as shown in [Table 1], WHSV = 1.2 h ^-1 , pressure = 60 bar, reaction temperature 350-358 It shows the product obtained by hydrogenation under conditions of ℃ and H ₂ /LCO = 2600 mL / mL.

The analysis results of HDT-LCO 1 and HDT-LCO 2 are shown in Table 1 below. In common, the content of bicyclic and tricyclic or more aromatic compounds greatly decreased and the content of monocyclic aromatic compounds increased significantly. It can be seen that HDT-LCO 2 treated at high WHSV has a lower monocyclic aromatic content, higher bicyclic and tricyclic aromatic contents, and increased sulfur and nitrogen compounds compared to HDT-LCO 1.

LCO HDT-LCO HDT-LCO 1 HDT-LCO 2 Catalysts Commercial catalyst
(VGO HDS Catalyst) Commercial catalyst
(VGO HDS Catalyst) WHSV,h ^-1 0.7 1.2 Temperature, 350-358 350-358 Pressure, bar 60 60 H ₂ /Feed, mL/mL 2500 2500 API 15.7 22.1 20.6 Sulfur, wtppm 3000 27 301 Nitrogen, wtppm 570 3.3 36 Aromatics,
wt% Mono (1 ring) 19.2 79.4 74.3 Di (2 rings) 54.8 7.5 13.6 Tri ⁺ (3 or more) 8.5 0.4 1.2 Total 82.5 87.3 89.1 SIM-GC, IBP 157 145 151 5% 208 202 205 50% 281 271 274 95% 382 373 377 FBP 426 430 430

Zeolite H-Beta (B) H-ZSM-5 (Z) Zeolite H-Y (Y) SiO ₂ /Al ₂ O ₃ molar ratio 75.0 30.0 80.0 Specific surface area (m ² /g) 650 405 780 Total pore volume (Vp)(cc/g) 0.35 0.21 0.54 Average pore size (nm) <1 <1 4.4

Composite zeolite B BZ-1 BZ-2 BYZ-1 BYZ-2 Beta content, wt% 100 90 80 85 80 Zeolite Y, wt% - - - 5 10 ZSM-5 content, wt% - 10 20 10 10

Manufacturing example 2: Preparation of catalyst for hydrocracking reaction

Methods for preparing the catalysts used in Examples and Comparative Examples of the present invention are as shown below.

(1) Catalyst 1: Mo(8)-S/B

The zeolite H-Beta (SiO ₂ /Al ₂ O ₃ =75.0) powder of Table 2 was impregnated with an aqueous solution in which a molybdenum precursor was dissolved to prepare a catalyst so that the molybdenum content was 8% by weight. The molybdenum precursor used in the preparation was ammonium molybdate tetrahydrate (H ₂₄ Mo ₇ N ₆ O ₂₄ ·4H ₂ O, hereinafter "AMT").

An aqueous solution prepared by dissolving AMT (0.331 g) in distilled water (2.5 ml) was impregnated in zeolite H-Beta powder (2.0 g) dried overnight at 80°C in air, dried at room temperature for 5 hours, and then overnight at 80°C. It was dried (8-14 hours). Then, the temperature was raised in air to 10°C per minute, maintained at 150°C for 1 hour, heated from 150°C to 5°C per minute, and fired at 500°C for 3 hours.

In Mo(8)-S/B, the numbers in parentheses represent the weight percent of Mo based on the total weight of the catalyst.

(2) catalyst 2: Mo (8)-S/ BZ -One Catalyst preparation

A catalyst was prepared in the same manner as in Catalyst 1, but zeolite H-Beta (SiO ₂ /Al ₂ O ₃ =75.0) and H-ZSM-5 (SiO ₂ /Al ₂ O ₃ ) of the [Table 2] as a zeolite component =30.0) was mixed in a weight ratio of 90:10 and the composite zeolite (BZ-1) powder of [Table 3] was used.

(3) Catalyst 3: Ni(3)-Mo(8)-S/BZ-1 Catalyst preparation

As a zeolite component, the composite zeolite (BZ-1) powder of [Table 3] was used. The composite zeolite (BZ-1) powder was impregnated with an aqueous solution of a nickel precursor and an aqueous solution of a molybdenum precursor to prepare a catalyst such that the content of nickel and molybdenum was 3% by weight and 8% by weight, respectively. Nickel nitrate hexahydrate (Ni(NO ₃ ) ₂ ·6H ₂ O, hereinafter "NNH") was used as the nickel precursor used in the manufacture, and ammonium molybdate tetrahydrate (H ₂₄ Mo) was used as the molybdenum precursor. ₇ N ₆ O ₂₄ ·4H ₂ O, hereinafter "AMT") was used.

A solution prepared by dissolving NNH (0.334 g) and AMT (0.331 g) in distilled water (2.5 ml) was impregnated in mixed zeolite BZ-1 powder (2.0 g) dried at 80° C. in air, and then dried overnight at room temperature. And dried at 80° C. overnight (8 to 14 hours). Then, the temperature was raised in air to 10°C per minute, maintained at 150°C for 1 hour, heated from 150°C to 5°C per minute, and fired at 500°C for 3 hours.

In Ni(3)-Mo(8)-S/BZ-1, the numbers in parentheses indicate the weight percent of Ni and Mo based on the total weight of the catalyst.

(4) Catalyst 4: Co(3)-Mo(8)-S/BZ-1 Catalyst preparation

A catalyst was prepared in the same manner as in Catalyst 3, but cobalt was used instead of nickel as a metal component. Cobalt (II) nitrate hexahydrate (Co(NO ₃ ) ₂ · 6H ₂ O, hereinafter "CNH", 0.333 g) was used as a precursor of cobalt, and AMT (0.331 g) was used as a precursor of molybdenum. .

In Co(3)-Mo(8)-S/BZ-1, the numbers in parentheses represent the weight percent of Co and Mo based on the total weight of the catalyst.

(5) Catalyst 5: Mo(8)-S/BZ-2 Catalyst preparation

A catalyst was prepared in the same manner as in Catalyst 1, but zeolite H-Beta (SiO ₂ /Al ₂ O ₃ =75.0) and H-ZSM-5 (SiO ₂ /Al ₂ O ₃ ) of the [Table 2] as a zeolite component =30.0) was mixed in an 80:20 weight ratio, and the composite zeolite (BZ-2) powder of Table 3 was used.

(6) Catalyst 6: Mo(8)-S/BYZ-1 Catalyst preparation

The catalyst was prepared in the same manner as in Catalyst 1, but the zeolite H-Beta (SiO ₂ /Al ₂ O ₃ =75.0) of [Table 2], zeolite HY (SiO ₂ /Al ₂ O ₃ =80.0) and H- ZSM-5 (SiO ₂ /Al ₂ O ₃ =30.0) was mixed in a weight ratio of 85:5:10 [Table 3] composite zeolite (BYZ-1) powder was used.

(7) Catalyst 7: Mo(8)-S/BYZ-2 Catalyst preparation

The catalyst was prepared in the same manner as in Catalyst 1, but the zeolite H-Beta (SiO ₂ /Al ₂ O ₃ =75.0) of [Table 2], zeolite HY (SiO ₂ /Al ₂ O ₃ =80.0) and H- ZSM-5 (SiO ₂ /Al ₂ O ₃ =30.0) was mixed in an 8:1:1 weight ratio of the composite zeolite (BYZ-2) powder of [Table 3].

Experimental Example 1: Hydrolysis reaction of model reactants (tetralin, Tetralin)

Prior to the hydrocracking experiment of hydrogenated HDT-LCO, a hydrocracking reaction was performed using tetralin as a model reactant to investigate the effect of the metal component of the hydrocracking catalyst. Among the catalysts for the hydrocracking reaction prepared in Preparation Example 2, the catalysts 2 to 4 having the same zeolite component but different metal components were dried and pretreated in the following manner, followed by hydrocracking reaction, and the result [ It is shown in Table 4].

In order to further illustrate the principle of the present invention, the catalysts for hydrocracking reaction prepared from Preparation Example 2 were molded into pellets having a size of 250 to 500 μm. 0.58 g of the shaped catalyst was charged to a fixed bed flow reactor, dried for 1 hour at 150° C. under argon flow (30 cc/min), and then reacted for sulfidation (10 vol%) under pressure 460 psi hydrogen flow (83.6 cc/min). A 1:1 molar ratio of toluene and 1,2,4-trimethylbenzene including dimethyl disulfide) is flowed at a flow rate of 0.168 cc/min, and the temperature is raised at a rate of 2.5 ℃/min and maintained at 400 ℃ for 2 hours. And sulfided.

After sulfiding the catalyst for hydrocracking reaction, lower the reactor temperature to 120°C at a rate of 2.5°C/min, change the conditions to a pressure of 882 psig and a hydrogen flow rate of 39.4 cc/min·g-cat, and change the reaction product to 0.02 cc/min. It was flowed at a flow rate of min·g-cat. Tetraline was used as the reactant, and the volume ratio of hydrogen/reactant was 1972 mL/mL. The flow rate of the reactant corresponds to WHSV (Weight Hourly Space Velocity) = 2.0 h ^-1 based on the tetralin flow rate and the catalyst mass. The reactor temperature was raised to the reaction temperature (350 to 450° C.), and after reaching a steady state, the reaction liquid product was recovered from the bottom of the gas/liquid separator, and the components of the liquid product were confirmed by GC-FID and GC/MS analysis. The performance of the catalyst was compared by calculating the yield of BTX, the yield of Alkyl-Bz and the yield of the liquid product, as shown in Equations 1 to 3 below.

[Equation 1]

Yield of BTX (wt%) = (BTX content in liquid product, wt%) × (Yield of liquid product) / 100

[Equation 2]

Alkyl-Bz yield (wt%) = (Alkyl-Bz content in liquid product, wt%) × (Liquid product yield) / 100

[Equation 3]

Yield of liquid product (wt%) = (weight of liquid product produced per unit time) / (weight of reactant injected per unit time) × 100

Temperature
(℃) Liquid product yield (wt%) BTX yield (wt%) Alkyl-Bz yield (wt%) BTX+Alkyl-Bz yield (wt%) Catalyst 2 375 74.6 42.1 12.4 54.5 Catalyst 3 375 78.9 31.8 10.2 42.0 Catalyst 4 375 76.5 41.0 11.6 52.6

[Table 4] The zeolite component is the same as the composite zeolite BZ-1 and shows the results of the hydrocracking reaction of tetralin, a model reactant, on three value catalysts 2 to 4 having different metal components.

On the catalyst 2 on which molybthenium (Mo) was supported and on the catalyst 4 on which cobalt (Co) and molybdenum (Mo) were supported together, the BTX yield was higher than 40 wt%, while nickel (Ni) and molybdenum The BTX yield was very low on the catalyst 3 on which (Mo) was supported together. The above result is interpreted as a result according to the difference in hydrogenation activity of the metal component since the zeolite components of catalysts 2 to 4 are the same. That is, in the case of Ni-Mo metal, it is interpreted that the hydrogenation activity is excessive and decalin is generated by the hydrogenation reaction of tetralin in the above [Scheme 2], and is converted to LPG and Naphtha by decomposition at the acid point of the zeolite, resulting in a low BTX yield. . On the other hand, the yields of BTX and BTX+Alkyl-Bz were very high on catalyst 2 or catalyst 4 on which Mo or Co-Mo, which has lower hydrogenation activity than Ni-Mo metal, is supported. Therefore, from the results of the hydrocracking reaction of tetralin according to Experimental Example 1, it can be confirmed that the effect of the hydrocracking reaction according to the difference in the metal component is significantly different when the zeolite component is the same in the catalyst for the hydrocracking reaction. .

Experimental Example 2: Hydrolysis reaction of HDT-LCO

HDT-LCO 1 and HDT-LCO 2 prepared from Preparation Example 1 were used as reactants, and the catalysts for hydrocracking reaction prepared from Preparation Example 2 were used in the same manner as in Experimental Example 1, and the formed catalyst was filled in the reactor and dried. And after the pretreatment, a hydrocracking reaction was performed, and the results are shown in [Table 5] and [Table 6] below.

Example 1: Hydrocracking reaction of HDT-LCO 2 on catalyst 6

Using the HDT-LCO 2 prepared from Preparation Example 1 as a reactant, and drying and pretreatment in the same manner as in Experimental Example 2 using the hydrocracking catalyst 6 prepared from Preparation Example 2, the hydrocracking reaction was performed. Performed.

Example 2: Hydrocracking reaction of HDT-LCO 2 on catalyst 7

The experiment was conducted in the same manner as in Example 1, but the catalyst 7 for hydrocracking reaction prepared from Preparation Example 2 was used.

Comparative Example 1: Hydrocracking reaction of HDT-LCO 2 on catalyst 2

The experiment was conducted in the same manner as in Example 1, but the catalyst 2 for hydrocracking reaction prepared from Preparation Example 2 was used.

Comparative Example 2: Hydrocracking reaction of HDT-LCO 1 on catalyst 1

The experiment was conducted in the same manner as in Example 1, but the HDT-LCO 1 prepared from Preparation Example 1 was used as a reactant, and the catalyst 1 for hydrocracking reaction prepared from Preparation Example 2 was used.

Comparative Example 3: Hydrocracking reaction of HDT-LCO 1 on catalyst 2

The experiment was conducted in the same manner as in Comparative Example 2, but the catalyst 2 for hydrocracking reaction prepared from Preparation Example 2 was used.

Comparative Example 4: Hydrocracking reaction of HDT-LCO 1 on catalyst 5

The experiment was conducted in the same manner as in Comparative Example 2, but the catalyst 5 for hydrocracking reaction prepared from Preparation Example 2 was used.

Temperature
(℃) Liquid product yield (wt%) BTX yield (wt%) Alkyl-Bz yield (wt%) BTX+Alkyl-Bz yield (wt%) C ₁₁ ⁺ aromatic yield
(wt%) Comparative Example 2 375 80.4 17.9 21.2 39.1 7.1 400 77.4 23.1 21.3 44.4 4.2 Comparative Example 3 375 73.3 21.5 20.1 41.6 8.8 400 64.9 25.0 17.7 42.7 5.6 Comparative Example 4 375 61.4 24.0 14.1 38.1 6.7 400 55.3 27.9 10.9 38.8 3.8

Temperature
(℃) Liquid product yield
(wt%) BTX yield (wt%) Alkyl-Bz yield (wt%) BTX+Alkyl-Bz yield
(wt%) C ₁₁ ⁺ aromatic yield
(wt%) Example 1 400 66.1 25.1 16.8 42.0 5.6 425 55.2 26.9 13.8 40.7 3.0 Example 2 400 62.1 30.1 14.0 44.1 2.2 425 51.4 30.6 10.1 40.7 0.8 Comparative Example 1 400 68.2 23.5 16.9 40.4 10.3 425 59.7 25.1 13.6 38.7 8.3

The results of the hydrocracking reaction of HDT-LCO 1 and HDT-LCO 2 according to Preparation Example 1 are shown in [Table 5] and [Table 6], respectively.

The results of the hydrocracking reaction according to Comparative Examples (Comparative Examples 2 to 4) of the present invention for HDT-LCO 1 according to Preparation Example 1 were compared in [Table 5]. Hydrocracking reaction results according to catalysts 2 and 5 for hydrocracking reaction with the addition of H-ZSM-5 with high acidity and small pore size to promote the conversion to BTX through dealkylation of Alkyl-Bz other than BTX (comparative When comparing Examples 3 and 4) with the results of the hydrocracking reaction according to the catalyst 1 for hydrocracking reaction without H-ZSM-5 (Comparative Example 2), the yield of Alkyl-Bz decreases and the BTX yield at the same reaction temperature. This increasing effect can be confirmed (Fig. 2). As shown in FIG. 2, the above effect increases as the H-ZSM-5 content increases. When the H-ZSM-5 content of the composite zeolite is 20 wt% (Comparative Example 4), the liquid product is It can be seen that the yield is very low and the yield of gaseous products (mainly LPG) is greatly increased. Therefore, it can be expected that if the H-ZSM-5 content is excessively high, the yield of BTX+Alkyl-Bz will also decrease. However, as a result of the hydrocracking reaction of HDT-LCO 1 according to Comparative Examples 2 to 4, the conversion rate of the C ₁₁ ⁺ aromatic compound having a large molecular size was low and the yield was relatively high due to the limitation of the pore size of the zeolite used in the hydrocracking reaction catalyst. . Therefore, if the catalyst for the hydrocracking reaction is designed so that the C ₁₁ ⁺ aromatic compound having a large molecular size is further hydrocracked, the yield of high-added BTX and BTX+Alkyl-Bz can be improved.

Accordingly, the hydrocracking reaction results of the hydrocracked HDT-LCO 2 according to Preparation Example 1 in Examples (Examples 1 to 2) of the present invention were compared to the hydrocracking reaction results according to Comparative Example 1 and [Table 6]. I did. Having mesopores in the composite zeolite used in the hydrocracking catalyst to promote the hydrocracking reaction of the unconverted C ₁₁ ⁺ aromatic compound having a large molecular size, referring to the hydrocracking results according to Comparative Examples 2 to 4 above. Catalysts 6 and 7 using composite zeolites BYZ-1 and BYZ-2 to which a small amount of zeolite Y was added were developed as catalysts for hydrocracking reaction. Compared with the results according to Comparative Example 1 using a catalyst for hydrocracking reaction that does not include zeolite Y having mesopores, in the results according to Examples 1 and 2, the conversion of C ₁₁ ⁺ aromatic having a large molecular size was promoted. It can be seen that the yield of C ₁₁ ⁺ aromatic decreases and the yield of BTX and BTX + Alkyl-Bz is greatly increased. Referring to [Table 6] and FIG. 3, in the result according to Example 2, while the yield of C ₁₁ ⁺ aromatics was very low, the BTX content increased to 30 wt% or more, and the yield of BTX + Alkyl-Bz was also 44 wt% or more. Was high. In the catalyst for hydrocracking reaction, the yield of the liquid product decreases as the content of zeolite Y having mesopores increases.If the content of zeolite Y is higher than a certain level, the yield of gaseous products (mainly LPG) increases due to excessive decomposition reaction, and BTX+ It can be expected that the yield of Alkyl-Bz will decrease.

Therefore, in order to obtain a light aromatic hydrocarbon containing BTX in high yield from LCO consisting mainly of monocyclic to tricyclic aromatics (bicyclic>monocyclic> tricyclic or more aromatic) having a wide molecular size distribution, the above results of the present invention Based on this, the catalytic roles of H-Beta, H-ZSM-5, and HY(USY) Zeolite constituting the catalyst for hydrocracking reaction are schematically expressed in FIG. 1. Among the aromatic compounds contained in LCO, the content of bicyclic aromatics is the highest (Table 1), so H-Beta having an appropriate pore size in the hydrocracking reaction of HDT-LCO is the main zeolite component and has the best selectivity for the decomposition reaction. In addition to BTX, there is a problem that various Alkyl-Bz and unconverted C ₁₁ ⁺ aromatic hydrocarbons having a large molecular size are combined with each other in high yield. Therefore, by adding an appropriate amount of H-ZSM-5 with high acidity and small pore size to promote the dealkylation/transalkylation reaction of Alkyl-Bz to improve the BTX yield, and to increase the BTX yield, and to add an appropriate amount of zeolite HY (USY) having mesopores. By adding it, it is possible to maximize the yield of BTX and BTX+Alkyl-Bz obtained by promoting the decomposition of C ₁₁ ⁺ aromatic compounds having a large molecular size. Here, the main components of Alkyl-Bz are trimethylbenzenes (C ₉ aromatics) and ethylbenzene (C ₈ aromatics). Trimethylbenzenes are useful substances for generating xylene through a separate transalkylation reaction with toluene, and ethylbenzene itself is a useful material that can be used as a high value petrochemical raw material or can be easily converted to benzene in a dealkylation/transalkylation reaction. It is a substance.

Therefore, according to the present invention, by using a catalyst in which a group VIB metal or a mixed metal of a group VIB and a group VIIIB metal is supported on the molecular size selectivity complex zeolite of zeolite beta, ZSM-5 and zeolite Y having mesopores, 1 C ₆ -C _{9 with} increased BTX content from LCO having various molecular sizes consisting of ring to three or more aromatic rings The effect of obtaining a range of light aromatic hydrocarbons in high yield can be achieved.

Claims (12)

(I) a composite zeolite of zeolite beta having 12-MR (membered ring) pore size, zeolite Y having 12-MR pore size and mesopores of 2 to 50 nm, and zeolite ZSM-5 having 10-MR pore size; And
(Ii) a Group VIB metal; including,
With respect to the total weight of the composite zeolite, the zeolite beta is 65 to 90% by weight, the zeolite Y is 1 to 20% by weight, and the zeolite ZSM-5 is 1 to 30% by weight,
The catalyst for molecular size selective hydrocracking reaction, characterized in that the group VIB metal is Mo. The method of claim 1,
The zeolite beta is a form consisting of SiO ₂ and Al ₂ O ₃ in a molar ratio of 50 to 90:1, a specific surface area of 550 to 750 m ² /g, a total pore volume of 0.2 to 0.4 cc/g, and an average pore Size is 1 nm or less;
The zeolite Y is a form consisting of SiO ₂ and Al ₂ O ₃ in a molar ratio of 10 to 50:1, a specific surface area of 650 to 850 m ² /g, a total pore volume of 0.4 to 0.6 cc/g, and an average pore It contains two kinds of pores of size 2 to 10 nm and 1 nm or less;
The zeolite ZSM-5 has SiO ₂ and Al ₂ O ₃ in a molar ratio of 60 to 100:1, a specific surface area of 300 to 500 m ² /g, and a total pore volume of 0.01 to 0.3 cc/g, Molecular size-selective hydrocracking catalyst, characterized in that the average pore size is 1 nm or less. The method of claim 1,
The catalyst for the molecular size selective hydrocracking reaction is a catalyst for a molecular size selective hydrocracking reaction, characterized in that it further comprises Pseudo Boehmite. delete The method of claim 1,
The group VIB metal is a catalyst for molecular size selective hydrocracking reaction, characterized in that the sulfide form. The method of claim 1,
The content of the composite zeolite is 50 to 95% by weight, based on the total weight of the hydrocracking reaction catalyst. delete The method of claim 1,
The Mo content is a molecular size selective hydrocracking catalyst, characterized in that 5-20% by weight based on the total weight of the hydrocracking reaction catalyst. (a) dissolving a group VIB metal precursor in distilled water to prepare an aqueous metal precursor solution;
(b) impregnating the composite zeolite of zeolite beta, zeolite Y and zeolite ZSM-5 with the aqueous metal precursor solution obtained in step (a); And
(c) drying the metal-supported composite zeolite obtained in step (b) and then firing it in an oven flowing with oxygen to obtain a composite zeolite-based catalyst containing metal together; and
With respect to the total weight of the composite zeolite, the zeolite beta is 65 to 90% by weight, the zeolite Y is 1 to 20% by weight, and the zeolite ZSM-5 is 1 to 30% by weight,
The method for producing a catalyst for molecular size-selective hydrocracking reaction, wherein the group VIB metal precursor is a Mo precursor. The method of claim 9,
The drying in step (c) is performed at room temperature for 4 to 7 hours, and then at 60 to 100°C for 8 to 14 hours,
The sintering of step (c) may include a first heat treatment step of raising the temperature from room temperature to a first heat treatment temperature between 100 to 300 °C at 8 to 12 °C/min; And a second heat treatment step of raising the temperature from the first heat treatment temperature to a second heat treatment temperature between 400 and 600° C. at 1 to 7° C./min., wherein the catalyst for molecular size-selective hydrocracking reaction Manufacturing method. A method for producing a light aromatic hydrocarbon in the range of C ₆ -C ₉ from a polycyclic aromatic hydrocarbon using the catalyst for molecular size selective hydrocracking reaction according to claim 1, in a reactor,
(1) drying the hydrocracking reaction catalyst;
(2) after raising the temperature of the reactor to 400 to 500° C., the pressure is adjusted to 400 to 1500 psig, and sulfurizing the hydrocracking reaction catalyst in a gas stream containing hydrogen;
(3) After lowering the reactor temperature to 120° C. or less, the pressure is adjusted to 500 to 1600 psig, and the hydrogen flow rate is adjusted to 30 to 100 cc/min·g-cat;
(4) flowing a polycyclic aromatic hydrocarbon at a flow rate of 0.01 to 3.3 cc/min·g-cat; And
(5) After reacting by raising the temperature of the reactor to 350 to 450 °C, recovering the reaction liquid product in a gas/liquid separator; characterized in that it comprises, from a polycyclic aromatic hydrocarbon in the range of C ₆ -C ₉ A method for producing aromatic hydrocarbons. The method of claim 11,
The polycyclic aromatic hydrocarbon is a method for producing a light aromatic hydrocarbon in the range of C ₆ -C ₉ from a polycyclic aromatic hydrocarbon, characterized in that conversion to a light aromatic hydrocarbon including BTX by using a monocyclic and a bicyclic aromatic hydrocarbon together.

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