KR101665577B1

KR101665577B1 - Hydrocracking catalysts for light alkyl-aromatic hydrocarbons, method for the preparation thereof and method for process for preparing light alkyl-aromatic hydrocarbons having the high content of xylene using the hydrocracking catalysts

Info

Publication number: KR101665577B1
Application number: KR1020140175029A
Authority: KR
Inventors: 이정규; 최예슬; 이지혜; 신재욱; 장순철; 강흥중; 강동일
Original assignee: 에쓰대시오일 주식회사; 동아대학교 산학협력단
Priority date: 2014-12-08
Filing date: 2014-12-08
Publication date: 2016-10-12
Also published as: KR20160069273A

Abstract

The present invention relates to a catalyst for hydrocracking reaction for producing a light aromatic hydrocarbon having an increased xylene content among BTX from polycyclic aromatic hydrocarbons, a process for producing the same, and a process for producing a light aromatic hydrocarbon having a high xylene content using the same . According to various embodiments of the present invention, a catalyst for the hydrogenolysis reaction of polycyclic aromatic hydrocarbons is a catalyst for hydrocracking reaction which inhibits the conversion of tetralin to naphthalene and the hydrogenation reaction to decalin, Among the light aromatic hydrocarbons containing BTX from tetralin and alkyl-tetralines obtained through hydrogenation in the presence of catalysts of polycyclic aromatic hydrocarbons such as naphthalene, alkyl-naphthalene and the like contained in the byproducts, Effect can be achieved.

Description

TECHNICAL FIELD The present invention relates to a catalyst for hydrocracking reaction for producing light aromatic hydrocarbons, a process for preparing the same, and a process for preparing a light aromatic hydrocarbon having a high xylene content using the catalyst, light alkyl-aromatic hydrocarbons having the high content of xylene using the hydrocracking catalysts}

The present invention relates to a catalyst for hydrocracking reaction for producing a light aromatic hydrocarbon having an increased xylene content among BTX from polycyclic aromatic hydrocarbons, a process for producing the same, and a process for producing a light aromatic hydrocarbon having a high xylene content using the same .

Among the byproducts of refinery and petrochemical processes, the LCO (Light Cycle Oil) of the Fluid Catalytic Cracker (FCC) process, the C10 ⁺ heavy aromatic of the Para-xylene process and the Pyrolysis Fuel Oil of the NCC (Naphtha Cracking Center) The content of hydrocarbons (Polycyclic Aromatic Hydrocarbons) is high, and the content of naphthalene and alkyl-naphthalene is high.

These byproducts are mainly sold at the bottom for viscosity control of heavy fuel oil or consumed in the fuel flow path of the self-process. However, since the demand for heavy fuel oil is rapidly declining, it is necessary to convert the by-products of the lower refinery and petrochemical processes, which have a low content of naphthalene and alkylnaphthalene, to high-value light aromatic hydrocarbons including BTX (Benzene, Toluene, Xylene) The economical efficiency of the related process can be greatly improved.

For example, in order to convert naphthalene into a high-value light aromatic hydrocarbon containing BTX, hydrogen is added in the presence of a catalyst to selectively hydrogenate only one benzene ring out of the two benzene rings of naphthalene, (Tetralin) with a Naphthene ring (Reaction Route 1), and the Tallaline ring of the Tetralin is degraded by subsequent hydrocracking (Reaction Route 2) to produce BTX have.

[Reaction Scheme 1]

Such BTX is used for various purposes after being produced in various kinds of resins in a petrochemical plant. In particular, BTX is used for polyester fiber in the case of xylene, and also used for mixing with volatiles when the demand for volatiles increases. It is necessary to secure the production amount.

On the other hand, both reaction pathways 1 and 1 'are reversible reactions determined by the thermodynamic equilibrium relationship and are activated by the metal catalysts. The hydrogenation reaction of tetralin in naphthalene is a strong exothermic reaction in which the total molar number decreases. The higher the pressure and the lower the reaction temperature, the higher the conversion of naphthalene and the higher the yield of tetralin. On the other hand, when the reaction temperature is high and the hydrogen pressure is low, the dehydrogenation reaction in which tetralin is converted back to naphthalene is dominant, resulting in a low conversion of naphthalene and a low yield of tetralin. The hydrogenation reaction in which tetralin is produced in tetralin is also advantageous as the pressure is higher and the temperature is lower.

Generally, the hydrocracking reaction is carried out at a high temperature and a high pressure so that tetralin can be re-converted to naphthalene by the dehydrogenation reaction (reverse reaction of reaction path 1), in which case the yield of the light aromatic hydrocarbons containing BTX is lowered . Further, when the hydrogenation activity of the hydrocracking catalyst is excessively high and the benzene ring of the tetralin is further hydrogenated to produce a large amount of decalin (Reaction Route 1 '), decalin is hydrocracked (Reaction Route 2'), To decompose into LPG and naphtha, resulting in a lower yield of light aromatic hydrocarbons including the final BTX and a higher hydrogen consumption.

Therefore, in order to maximize the yield of light aromatic hydrocarbons containing high-value BTX, the re-conversion of tetralin to naphthalene (reverse reaction of Reaction Route 1) and the hydrogenation of tetralin to decalin in the hydrogenolysis of tetralin (Reaction pathway 1 '). For this purpose, there is a need for a hydrocracking catalyst that maximizes the yield of light aromatic hydrocarbons including BTX by minimizing the production of LPG and naphtha by appropriately controlling the hydrogenation function of the catalyst for hydrocracking reaction.

However, in general, when using a catalyst for hydrocracking reaction, the content of xylene in BTX is lowest in the order of benzene> toluene >> xylene. Therefore, as described above, it is required to develop a new catalyst for increasing the content of xylene used in various fields in BTX.

A problem to be solved by the present invention is to provide a catalyst for the production of high-priced light aromatic hydrocarbons having increased xylene content among BTX from naphthalene or polycyclic aromatic hydrocarbons such as alkyl-naphthalene contained in by-products of refinery and petrochemical processes, And a method for producing a light aromatic hydrocarbon having an increased xylene content using the catalyst.

According to an exemplary aspect of the present invention, there is provided a method for producing a zeolite catalyst, comprising the steps of: (A) adding a zeolite carrier containing (B) a Group VIII metal alone or a Group VIII metal and a Group IV metal, A catalyst for hydrogenolysis reaction for producing light aromatic hydrocarbons, a process for preparing the same, and a process for producing a light aromatic hydrocarbon having an increased xylene content using the process.

According to various embodiments of the present invention, a catalyst for the hydrogenolysis reaction of polycyclic aromatic hydrocarbons is a catalyst for hydrocracking reaction which inhibits the conversion of tetralin to naphthalene and the hydrogenation reaction to decalin, Among the light aromatic hydrocarbons containing BTX from tetralin and alkyl-tetralines obtained through hydrogenation in the presence of catalysts of polycyclic aromatic hydrocarbons such as naphthalene, alkyl-naphthalene and the like contained in the byproducts, Effect can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a plot of BTX content (wt%) in the liquid product versus tetralin conversion according to one embodiment of the present invention.
Figure 2 is a plot of BTX yield (wt%) versus tetralin conversion according to one embodiment of the present invention.
FIG. 3 is a graph showing the hydrogenation reaction activity of tetralin against the metal component of the hydrocracking catalyst according to an embodiment of the present invention, wherein (a) shows the conversion of tetralin according to the reaction temperature and (b) And shows the yield of decalin according to the reaction temperature.
FIG. 4 is a graph showing gas chromatograms of a reactant used in an embodiment of the present invention and a liquid product according to an embodiment of the hydrogenolysis reaction, wherein (a) liquid product after C10 ⁺ heavy aromatic hydrotreatment in the actual Para- (b) The gas chromatogram of the liquid product according to the hydrocracking reaction of the C10 ⁺ heavy aromatic of the para-xylene process with hydrogenation as a reactant.

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

The term " hydrocracking reaction of polycyclic aromatic hydrocarbons "as used herein refers to hydrocracking an aromatic compound having a sulfone ring formed by adding hydrogen in the presence of a catalyst in the presence of a polycyclic aromatic hydrocarbon. The aromatic hydrocarbons include naphthalene For example, as shown in Reaction Scheme 2 below, naphthalene is hydrogenated in the presence of a catalyst to selectively hydrogenate only one benzene ring out of the two benzene rings constituting naphthalene to form tetralin Tetralin) is formed and the cascade ring of tetralin is opened and decomposed through a continuous hydrocracking reaction to finally produce a light aromatic hydrocarbon containing BTX.

[Reaction Scheme 2]

Techniques for converting polycyclic aromatic hydrocarbons having two or more benzene rings such as naphthalene and alkyl-naphthalene into high-value light aromatic hydrocarbons including BTX, which are included in byproducts of refinery and petrochemical processes using conventional hydrocracking catalysts However, the problem that the yield of BTX is not high can be solved. Particularly, according to one embodiment of the present invention, the hydrocracking catalyst is composed of two benzene rings of a bicyclic aromatic hydrocarbon such as naphthalene having a high content among polycyclic aromatic hydrocarbons, and one benzene ring is selectively hydrogenated to form naphthalene By controlling the conversion and hydrogenation reaction to decalin (see Reaction Scheme 1 above), the light aromatic hydrocarbons including the final BTX can be obtained in high yield.

Here, the by-products of the refinery and petrochemical processes include LCO (Light Cycle Oil) of the FCC process, C10 ⁺ heavy aromatic of the para-xylene process and PFO (Pyrolysis Fuel) of the NCC (Naphtha Cracking Center) The by-products mainly include bicyclic aromatic hydrocarbons such as naphthalene and methyl-naphthalene, and all hydrocarbons including polycyclic aromatic hydrocarbons. The light aromatic hydrocarbons include BTX (Benzene, Toluene, Xylene ) And a hydrocarbon having 6 to 9 carbon atoms including an alkyl-substituted benzene.

In one aspect of the present invention, there is provided a catalyst for hydrocracking reaction, which comprises (A) a zeolitic carrier containing (B) a Group VIIIB metal supported thereon and a light aromatic hydrocarbon having an increased xylene content from polycyclic aromatic hydrocarbons as,

The zeolite carrier comprises (A) a Group IV metal. A catalyst for hydrogenolysis reaction for producing a light aromatic hydrocarbon having an increased xylene content from polycyclic aromatic hydrocarbons is disclosed.

(i) 1.1 to 9.9% by weight, based on the total weight of the catalyst for hydrocracking reaction of hydrocarbons, of Group VIIIB metal is supported on the zeolitic carrier by itself,

(ii) When the group VIIIB metal and the group IV metal are supported together on the zeolitic carrier, the group VIIIB metal and the group IV metal are each contained in an amount of 1.1-7 wt% based on the total weight of the catalyst for hydrocracking reaction of hydrocarbon A catalyst for hydrocracking reaction for producing light aromatic hydrocarbons with increased xylene content from polycyclic aromatic hydrocarbons is disclosed.

According to an embodiment of the present invention, when only the Group VIIIB metal constituting the catalyst is supported on the zeolitic carrier and the amount is less than 1.1 wt% based on the total weight of the catalyst, the number of active sites of the catalyst is decreased, And the amount of C ₉ ⁺ heavy aromatics is increased, so that the BTX content in the liquid product is low and the stability of the hydrocracking catalyst due to coke deposition or the like is lowered. When the amount of 4.9 wt% , The hydrogenation function of the catalyst is excessively high, so that after the conversion of tetralin to decalin, decomposition occurs to increase the production of LPG and Naphtha, resulting in a decrease in the yield of liquid product and final BTX, and an increase in hydrogen consumption There is a problem.

In addition, when the hydrogenation activity of the Group VIII metal is excessively high, there is a problem in that the conversion of tetralin to decalin decomposes after decomposition to increase the production of LPG and naphtha, When used together, the hydrogenation activity of a Group VIII metal is inhibited and the final BTX yield can be improved.

At this time, it is preferable that the Group VIIIB metal and the Group IV metal are contained in a weight ratio of 2-5: 3-5. If the ratio is out of the above range, a decrease in tetralin conversion, decalin selectivity and decalin yield is conspicuous .

Meanwhile, in another embodiment of the present invention, when the polycondensation reaction of polycyclic aromatic hydrocarbons is performed using tetralin or methyl-tetralin and a C ₁₀ aromatic isomer, the xylene content may be increased in BTX There is an effect.

In another embodiment of the present invention, the C ₁₀ aromatic isomer is selected from the group consisting of 1,2,4,5-tetramethylbenzene (durene), 1,2,3,5-tetramethylbenzene (isodurene) And 3,4-tetramethylbenzene (prehnitene).

In another embodiment of the present invention, the group VIIIB metal is at least one selected from the group consisting of Ni, Co, Mo and Fe, the group IV metal is at least one selected from Sn, Ge and Pb, Group metals are Ni and Group IV metals are Sn.

In another embodiment of the present invention, the zeolite carrier (B) is at least one selected from zeolite Beta, ZSM-5 and mordenite, and the zeolite carrier is preferably zeolite Beta, The carrier is characterized in that SiO ₂ and Al ₂ O ₃ are mixed in a molar ratio of 15-40: 1.

When the molar ratio of SiO ₂ and Al ₂ O ₃ is out of the above range among the above-mentioned zeolite carriers, especially when the molar ratio is low, the acidity is high and the decomposition reaction is excessive, so that the amount of gas (LPG) and naphtha is large, And the hydrogen partial pressure is excessively low, the conversion of tetralin to naphthalene is reduced due to the thermodynamic equilibrium relationship in the hydrogenolysis reaction of tetralin, and the conversion of tetralin decreases, The yield of hydrocarbons was reduced.

According to another aspect of the present invention, there is provided a process for producing a catalyst for hydrocracking reaction of polycyclic aromatic hydrocarbons,

(a) preparing an aqueous solution by dissolving Group VIII alone or Group VIII metal and Group IV metal precursor together in distilled or aqueous hydrochloric acid;

(b) impregnating the zeolite-based catalyst with the aqueous solution obtained in step (a);

(c) drying the support obtained in the step (b), and then calcining the support in an oven in which oxygen flows, thereby obtaining a zeolite catalyst containing a Group VIII metal alone or a Group VIII metal and a Group IV metal A process for preparing a catalyst for hydrocracking reaction to produce a light aromatic hydrocarbon having an increased xylene content from polycyclic aromatic hydrocarbons.

According to another aspect of the present invention, there is provided a process for producing a light aromatic hydrocarbon using a catalyst for hydrocracking reaction of polycyclic aromatic hydrocarbons,

(1) drying or reducing a catalyst for hydrocracking reaction of polycyclic aromatic hydrocarbons;

(2) lowering the reactor temperature to 150 ° C or less, adjusting the pressure to 400-1500 psig, and adjusting the hydrogen flow rate to 20-100 cc / min · g-cat;

(3) flowing polycyclic aromatic hydrocarbons at a flow rate of 0.3-3.3 cc / min · g-cat;

(4) a step of raising the temperature of the reactor to 350-450 DEG C to react, and recovering the reaction liquid product in a gas / liquid separator.

In one embodiment of the present invention, the light aromatic hydrocarbon is at least one selected from benzene, toluene, xylene, ethylbenzene, propyl-benzene, and trimethyl-benzene.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It is natural that it belongs to the claims.

Example 1 Preparation of Ni (5) -Sn (3) / H-Beta (Si / Al = 37.5)

A 1M HCl solution in which a nickel precursor was dissolved in a zeolite Beta (Si / Al = 37.5) powder and a tin precursor was impregnated to prepare a catalyst such that the nickel and tin contents were 5 wt% and 3 wt%, respectively. Nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ .6H ₂ O, hereinafter referred to as "NNH") was used as the nickel precursor used in the preparation, and tin chloride dihydrate (SnCl ₂ .2H ₂ O, Hereinafter "TCD") was used.

The solution prepared by dissolving TCD (0.12 g) in 1M HCl (2.6 ml) was impregnated with 2.0 g of zeolite Beta (Si / Al = 37.5) dried at 80 ° C. in air, After drying, the aqueous solution prepared by dissolving NNH (0.55 g) in distilled water (2.4 ml) is impregnated with zeolite Beta powder (2.1 g) impregnated with TCD solution. Thereafter, the catalyst was dried at 80 ° C. overnight, and then calcined at 400 ° C. for 4 hours in air to prepare a Ni (5) -Sn (3) / H-Beta catalyst.

The numbers in parentheses in Ni (5) -Sn (3) / H-Beta represent weight percent of Ni and Sn based on the total weight of the catalyst.

Example 2: Preparation of Ni (5) -Sn (3) / H-Beta (Si / Al = 19)

A catalyst was prepared in the same manner as in Example 1 except that zeolite Beta (Si / Al = 19) powder having different Si / Al ratio was used.

Example 3 Preparation of Ni (5) -Sn (5) / H-Beta (Si / Al = 37.5)

A catalyst was prepared in the same manner as in Example 1 except that the Sn content was 5 wt% based on the total weight of the catalyst.

Example 4: Preparation of Ni (2) -Sn (3) / H-Beta (Si / Al = 37.5)

A catalyst was prepared in the same manner as in Example 1 except that the Ni content was 2 wt% and the Sn content was 3 wt% based on the total weight of the catalyst.

Example 5: Preparation of Ni (2) / H-Beta catalyst

Zeolite Beta (Si / Al = 37.5) powder was impregnated with an aqueous solution of a nickel (Ni) precursor to prepare a catalyst having a nickel content of 2 wt%. Nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ .6H ₂ O, hereinafter referred to as "NNH") was used as the nickel precursor used in the production.

An aqueous solution prepared by dissolving NNH (0.52 g) in distilled water (2.6 ml) was impregnated with zeolite Beta (Si / Al = 37.5) powder dried at 80 ° C in air and dried overnight at 80 ° C. Thereafter, the resultant was fired in air at 500 DEG C for 2 hours to prepare Ni (2) / H-Beta (Si / Al = 37.5).

The numbers in parentheses in Ni (2) / H-Beta represent the weight percent of Ni based on the total weight of the catalyst.

Comparative Example 1: H-Beta (Si / Al = 37.5) catalyst

Zeolite Beta (SiO ₂ / Al ₂ O ₃ = 75, Si / Al = 37.5) powder was used as a catalyst.

Comparative Example 2: Preparation of Ni (1) / H-Beta (Si / Al = 37.5) catalyst

A catalyst was prepared in the same manner as in Example 5 except that the content of Ni was 1 wt% based on the total weight of the catalyst.

Comparative Example 3: Preparation of Ni (5) / H-Beta (Si / Al = 37.5) catalyst

A catalyst was prepared in the same manner as in Example 5 except that the content of Ni was 5 wt% based on the total weight of the catalyst.

Comparative Example 4: Preparation of Ni (10) / H-Beta (Si / Al = 37.5) catalyst

A catalyst was prepared in the same manner as in Example 5 except that the content of Ni was 10 wt% based on the total weight of the catalyst.

Comparative Example 5: Ni (5) /? - Al ₂ O ₃ Catalyst preparation

A catalyst was prepared in the same manner as in Comparative Example 3, except that gamma-alumina (? -Al ₂ O ₃ ) was used instead of zeolite Beta as a catalyst support.

Comparative Example 6: Ni (5) -Sn (3) / gamma -Al ₂ O ₃ Catalyst preparation

A catalyst was prepared in the same manner as in Example 1, except that gamma-alumina (? -Al ₂ O ₃ ) was used instead of zeolite Beta as a catalyst support.

Experimental Example 1: Hydrogenolysis of tetralin

Tetraline was used as a model reaction, and the catalysts obtained in Examples 1 to 5 and Comparative Examples 1 to 4 were dried and reduced in the following manner, followed by hydrocracking reaction, 1] to [Table 3] and [Figure 1] to [Figure 2].

In order to further illustrate the principles of the present invention, catalysts prepared by the methods of all of the preceding and comparative examples were formed into 250-500 μm size. 0.58 g of the shaped catalyst was charged to a fixed bed flow reactor and either reduced or dried at 450 DEG C for 1-2 hours under hydrogen flow (60 cc / min) or helium flow (10 cc / min). At this time, the reduction and drying time were differently applied to each catalyst.

That is, all Ni-Sn and Ni supported catalysts (Examples 1-5 and Comparative Examples 1-4) were subjected to reduction treatment at 450 ° C under hydrogen flow for 1 hour, and in the case of H-Beta catalyst (Comparative Example 1) Lt; RTI ID = 0.0 > 450 C < / RTI > for 2 hours.

After the catalyst was dried and reduced, the temperature of the reactor was lowered to 120 ° C., and the conditions were changed at a pressure of 588 psig and a hydrogen flow rate of 45 cc / min · g-cat, and the reactant was flowed at a flow rate of 0.034 cc / min · g-cat. Tetralin was used as the reactant, and the hydrogen / tetralin molar ratio was 8.0. The reactant flow rate corresponds to a weight hourly space velocity (WHSV) of 2 h ^-1 on the basis of tetralin. The reaction liquid product was recovered from the bottom of the gas / liquid separator after the reactor temperature was raised to the reaction temperature and reached the steady state, and the components in the liquid product were analyzed by GC-FID and confirmed by GC / MS analysis. The performance of the catalyst was calculated by comparing the conversion of tetralin, the selectivity and yield of BTX in the liquid product as shown in the following equations (1) to (4).

[Equation 1]

Conversion of tetralin (wt%) = (100 - Tetraline content in liquid product, wt.%) / 100 x 100

&Quot; (2) "

Selectivity of BTX (%) = (content of BTX in liquid product, wt%) / (conversion of tetralin) x 100

&Quot; (3) "

BTX content in liquid product (wt%) = (conversion of tetralin) x (selectivity of BTX) / 100

&Quot; (4) "

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

&Quot; (5) "

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

Hydrogenolysis of Tetralin (hydrogen / tetralin = 8) catalyst reaction
Temperature
(° C) Tetralin
Conversion Rate
(wt%) 1-Cyclic Aromatic Hydrocarbon Content Without Having a Hexane Ring (wt%) BTX content in liquid product (%) Liquid product
yield
(wt%) BTX yield (wt%) Example 1 425 98.5 88 60.6 73.6 44.6 450 99.5 91.1 64.2 71.8 46.1 Example 2 425 99.0 80 54.6 68.9 37.7 450 99.5 86 60.4 67.1 40.5 Example 3 425 99.0 84.6 57.3 74.6 42.8 450 99.5 86 67.1 71.7 48.1 Example 4 425 94.7 72.4 34.3 84.5 29.0 450 97.9 76.6 43.0 82.2 35.4 Example 5 425 99.0 73.7 54.3 55.6 30.2 450 99.5 85.7 69.5 58.5 40.7 Comparative Example 1 425 88.3 62.3 29.3 94 27.6 450 83.7 59.1 34.8 95.2 33.1 Comparative Example 2 425 95.0 55.8 31.9 89.5 28.5 450 96.1 66.3 39.3 83.3 32.7 Comparative Example 3 425 96.8 57.7 28.1 81.4 22.9 450 99.1 69.8 45.7 67.6 30.9 Comparative Example 4 425 94.6 69.5 44.2 55.6 24.6 450 94.8 47.7 24.9 28.2 7

As shown in Table 1 and FIGS. 1 and 2, the Ni-Sn / H-Beta catalyst and the Ni / H-Beta catalyst according to the embodiment of the present invention all have a high The conversion rate was shown, but the final BTX yield showed a large difference.

On the other hand, the hydrocracking catalyst of Comparative Example 1 (H-Beta) containing no metal showed low conversion of tetralin, BTX content in liquid product and BTX yield. The hydrocracking catalysts of Comparative Examples 2 to 4 in which Sn was not added to the Ni metal as a cocatalyst were also compared with the catalysts of Examples 1 to 5 under the same reaction conditions to determine the amount of monocyclic aromatic hydrocarbons And the final BTX yield was low. In particular, in the hydrocracking catalyst (Comparative Example 4) in which Sn was not added and the Ni content was excessively high, the yield of liquid product and BTX was extremely low due to the hydrogenation reaction of tetralin to decalin and the subsequent hydrocracking reaction.

Among the hydrocracking catalysts according to Examples 1 to 5 according to the present invention, the hydrocracking catalysts according to Example 1 and Examples 3 to 4, in which Sn was added as a co-catalyst to Ni metal, The decomposition reaction showed high tetralin conversion and BTX yield.

The detailed distribution of the liquid product obtained in the hydrogenolysis reaction of tetralin on the hydrocracking catalyst according to Example 3 of the present invention is shown in Table 2 below. As shown in Table 2 below, the content of BTX (Benzene, Toluene, Xylene) was in the order of Benzene> Toluene >> Xylene at a hydrogenation reaction temperature of 425-450 ° C., and the content of ethylbenzene was 7.7- 10 wt%.

Distribution (unit: wt%) of liquid product by hydrocracking reaction of tetralin on the hydrocracking catalyst according to Example 3 main ingredient Reaction temperature (캜) 425 450 Tetralin 1.0 0.5 Non-aromatic hydrocarbon 8.3 7.3 Ethylbenzene 10.0 7.7 benzene 30.4 31.8 toluene 21.0 26.4 Xylene 6.0 8.9 C ₉ aromatic hydrocarbons 7.9 6.6 Indan 0.1 0.0 Methyl-indane 0.1 0.0 Decalin 0.0 0.0 naphthalene 2.4 2.5 2-methylnaphthalene 2.4 2.5 1-methylnaphthalene 1.1 1.1 Other C ₁₀ aromatic hydrocarbons 5.9 2.8 Other C ₁₁ aromatic hydrocarbons 1.8 0.7 Other C ₁₁ ⁺ aromatic hydrocarbons 1.6 1.2 Sum 100.0 100.0

Further, in order to analyze the effect of hydrogen partial pressure in the hydrogenolysis reaction of tetralin, other conditions on the hydrocracking catalyst according to Example 1 were the same as in the above experimental example, but the molar ratio of hydrogen / tetralin was reduced to 4.0, Were compared to those in Table 3 below.

Influence of hydrogen partial pressure on hydrogenolysis of tetralin catalyst Hydrogen / tetralin mole ratio reaction
Temperature
(° C) Tetralin
Conversion rate (wt%) Non-tethered
1 Cyclic Aromatic Hydrocarbon Content (wt%) Among liquid products
BTX content (wt%) Among liquid products
Naphthalene content (wt%) Liquid product yield (wt%) BTX yield (wt%) Example 1 4 450 95.7 76.7 43.6 5.0 81.5 35.5 8 450 99.5 91.1 64.2 1.3 71.8 46.1

As shown in the above Table 3, when the hydrogen / tetralin molar ratio in the hydrogenolysis of tetralin using the hydrogenolysis catalyst of Example 1 according to the present invention is as low as 4, The lower BTX yield was due to lower triral conversion and BTX content in the liquid product. Particularly, when the hydrogen / tetralin molar ratio is as low as 4, the hydrogen partial pressure is low, so that in the high temperature reaction, tetralin is converted into naphthalene, and naphthalene is produced in a large amount.

Experimental Example 2: Tetralin's Hydrogenation reaction

As described above, the hydrocracking catalysts according to Examples 1 to 4, in which Sn was added as a co-catalyst to Ni metal catalyst, showed a high final BTX yield in hydrogenolysis of tetralin. Therefore, in order to analyze the catalytic effect of Sn added as a co-catalyst, Ni (5) / γ-Al ₂ O ₃ catalyst loaded with Ni only on a γ-Al ₂ O ₃ carrier having a low acidity and little hydrocarbons decomposition activity Comparative Example 5) and Ni (5) -Sn (3) /? -Al ₂ O ₃ catalyst with Sn added with Ni (Comparative Example 6) were prepared and the hydrogenation of tetralin was carried out. The hydrogenation reaction of tetralin was performed under the same conditions as the hydrogenolysis reaction of tetralin described in Experimental Example 1, wherein the hydrogen / tetralin molar ratio was 8.0. The results are compared in Table 4 and FIG. 3 using the above-described Equation 1 and the following Equations 6 to 9.

&Quot; (6) "

Selectivity of decalin (%)

= (Content of decalin in liquid product, wt%) / (conversion of tetralin) x 100

&Quot; (7) "

Selectivity of naphthalene (%)

= (Content of naphthalene in liquid product, wt%) / (conversion of tetralin) x 100

&Quot; (8) "

Yield of decalin (wt%)

= (Conversion of tetralin) x (degree of selectivity of decalin) / 100

&Quot; (9) "

Yield of naphthalene (wt%)

= (Conversion of tetralin) x (selectivity of naphthalene) / 100

Hydrogenation of Tetralin catalyst Reaction temperature
(° C) Tetralin
Conversion rate (wt%) Decalin
Selectivity (%) Decalin
Yield (wt%) Comparative Example 5 425 66.8 90.1 60.2 450 44.5 51.6 23.0 Comparative Example 6 425 28.8 75.1 21.6 450 21.9 14.7 3.2

As shown in [Table 4] and FIG. 3, the thermoluminescence equilibrium relationship related to the hydrogenation reaction indicated that the higher the reaction temperature, the lower the tetralin conversion, the decalin selectivity and the yield.

In particular, on the Ni (5) / γ-Al 2 O 3 catalyst (Comparative Example 5) and Ni (5) -Sn (3) / γ-Al 2 O 3 catalyst (Comparative Example 6), as compared to FIG. 3 (5) -Sn (3) / γ-Al ₂ O ₃ catalyst according to Comparative Example 6 was compared with the Ni (5) / γ-Al ₂ O ₃ catalyst according to Comparative Example 5 in the hydrogenation reaction of tetralin The conversion of tetralin and the yield of decalin were greatly reduced under the same conditions. It is interpreted that the addition of Sn as a cocatalyst inhibits the hydrogenation activity of Ni.

Therefore, in the catalysts according to Examples 1 and 3 to 4, in which Sn was added as a cocatalyst in the hydrocracking catalysts according to Examples 1 to 5, a high final BTX yield was exhibited because Sn was added to decrease the hydrogenation activity of Ni, The hydrogenation of tralline to decalin is inhibited, and as a result, it can be confirmed that most of the Tallaline rings of the Tallaline ring are ring-opened / decomposed and converted to BTX.

Experimental Example 3: C10 of para-xylene process ⁺ Hydrogenolysis of Heavy Aromatics

In order to confirm the performance of the hydrocracking catalyst according to the embodiment of the present invention, the hydrocracking reaction was tested using a C ₁₀ ⁺ heavy aromatics produced in an actual para-xylene process as an example of polycyclic aromatic hydrocarbons as a reactant. As shown in Reaction Schemes 1 and 2, naphthalene and alkyl-naphthalene having two benzene rings contained in polycyclic aromatic hydrocarbons are converted into tetralin and alkyl-tetralin by the addition of hydrogen in the presence of a catalyst, The composition of C ₁₀ ⁺ heavy aromatics before hydrotreating is shown in Table 5 below. As shown in Table 5, the content of naphthalene and methyl-naphthalene after the hydrogenation treatment was greatly decreased, but the contents of tetralin and methyl-tetralin were increased greatly. In addition, the C ₁₀ ⁺ heavy aromatics produced in the actual para-xylene process have a high content of tetramethylbenzene (C ₁₀ Aromatics), which has a benzene ring, and include methylbiphenyl having two or more benzene rings, Phenyl, and the like.

Composition of C ₁₀ ⁺ heavy aromatic before and after hydrotreating (unit: wt%) main ingredient Before hydrotreatment
(C ₁₀ ⁺ heavy aromatic) After hydrotreating Non-aromatic hydrocarbon - 0.1 Ethylbenzene - 0.3 benzene - 0 toluene - 0.2 Xylene - 1.2 C ₉ aromatic hydrocarbons 0.1 2.4 1,2,4,5 tetramethylbenzene 2.2 2 1,2,3,5 tetramethylbenzene 4.3 4.5 1,2,3,4-tetramethylbenzene 9.6 9.3 Methyl-indane 2.4 2.5 Tetralin 0.2 11.9 Methyl-tetralin 0.6 6.6 naphthalene 9.8 0.5 2-methylnaphthalene 8.5 1.2 1-methylnaphthalene 4.1 0.4 Other C ₁₀ aromatic hydrocarbons 8.4 6.5 Other C ₁₁ aromatic hydrocarbons 11.6 22.9 Other C ₁₁ ⁺ aromatic hydrocarbons 38.2 27.3 Sum 100.0 100.0

In Experimental Example 3, the reaction product in the hydrocracking reaction in Experimental Example 1 was changed to the C ₁₀ ⁺ heavy aromatic of the actual para-xylene process which was hydrogenated, and the hydrogenation reaction of tetralin And the reaction was carried out under the same conditions as those described above. The results of hydrocracking reaction using the hydrocracking catalyst (Ni (5) -Sn (5) / H-Beta (Si / Al = 37.5) according to Example 3 are shown in Table 6 below. As shown in the following equations (10) to (14).

&Quot; (10) "

Conversion of tetralin (wt%)

= (Tetraline content in reactant, wt% - Tetralin content in liquid product, wt.%) / (Tetralin content in reactant, wt.%) X 100

&Quot; (11) "

Conversion of methyl-tetralin (wt%)

= Methyltetralin content in the reactant, wt.% - methyltetralin content in the liquid product, wt.%) / (Methyltetralin content in the reactant, wt.

&Quot; (12) "

Conversion of tetralin (wt%)

= (Content of tetralin in reactant,% by weight - content of tetralin in liquid product,% by weight) / (content of tetralin in reactant, wt.%) X 100

&Quot; (13) "

BTX selectivity (%)

= (Content of BTX in liquid product, wt%) / (conversion of tetralin) x 100

&Quot; (14) "

Yield (wt%) of BTX

= (BTX content in liquid product, wt%) x (yield of liquid product) / 100

Results of hydrocracking of hydrogenated C ₁₀ ⁺ heavy aromatic Reaction temperature (캜) 425 450 Reaction product component (wt%) Non-aromatic hydrocarbon 10.5 8.3 Ethylbenzene 2.5 1.7 benzene 3.8 4.1 toluene 17.0 19.8 Xylene 27.4 31.7 Ethyl toluene 7.9 5.6 1,3,5-trimethylbenzene 4.7 4.9 1,2,4-trimethylbenzene 10.9 11.6 1,2,3-trimethylbenzene 1.5 1.7 1,2,4,5 tetramethylbenzene 1.1 1.0 1,2,3,5 tetramethylbenzene 1.3 1.3 1,2,3,4-tetramethylbenzene 0.4 0.3 Tetralin 0.2 0.1 Methyl-tetralin 0.3 0.1 naphthalene 0.1 0.1 2-methylnaphthalene 0.1 0.2 1-methylnaphthalene 0.1 0.1 Other C9 aromatic hydrocarbons 0.6 0.3 Other C10 aromatic hydrocarbons 4.6 2.9 Other C11 aromatic hydrocarbons 1.3 0.6 Other C11 + aromatic hydrocarbons 3.5 3.6 Sum 100.0 100.0 Tetralin conversion, wt% 99.1 99.5 Methyl-tetralin conversion, wt% 98.7 99.5 Tetralin conversion, wt% 97.2 98.6 The BTX content in the liquid product, wt% 48.2 55.6 Liquid product yield, wt% 83.2 74.5 BTX yield, wt% 40.1 41.4

According to Experimental Example 3 of the present invention, Tetralin and methyl-tetralin contained in the C ₁₀ ⁺ heavy aromatic hydrotreated on the hydrocracking catalyst according to Example 3 and tetramethyl Benzene (1,2,4,5-, 1,2,3,5- and 1,2,3,4-tetramethylbenzene) was very high (Table 6). The conversion of other C ₁₀ -C ₁₁ ⁺ heavy aromatics is also very high. The final BTX yields were 40.1 and 41.4 wt% at the hydrocracking reaction temperatures of 425 캜 and 450 캜, respectively. In fact, in the production process of para-xylene, trimethylbenzenes (1,3,5-, 1,2,4- and 1,2,3-trimethylbenzene) can be converted to xylene by a disproportionation reaction with toluene The yields of total aromatic hydrocarbons in the C ₆ -C ₉ range including BTX and trimethylbenzenes were 57.2 and 59.6 wt% at the hydrocracking temperatures of 425 ° C and 450 ° C, respectively.

According to Experimental Example 3 of the present invention, the content of BTX in the liquid product as a result of hydrocracking of the hydrogenated C ₁₀ ⁺ heavy aromatics was in the order of Xylene> Toluene >> Benzene as shown in Table 6 above , And the content of ethylbenzene was 1.7-2.5 wt%. The results show a remarkable difference from the liquid product composition (Table 2) by the hydrogenolysis reaction using tetralin as a model component in the same hydrocracking catalyst (Example 3), and the high addition xylene content is high A low content of ethylbenzene is a very desirable result. A significant increase in the content of Xylene in BTX versus the hydrocracking reaction of tetralin in the hydrocracking of the hydrogenated C ₁₀ ⁺ heavy aromatics is interpreted as a result of the following reaction formula (3). That is, the tetra, which is much contained in the heavy C ₁₀ ⁺ aromatics Benzene and Toluene and actual process is obtained in a high yield in the hydrogenolysis of Te Neutral rinryu methyl benzenes (1,2,4,5, 2,3 , 5-and 1,2,3,4-tetramethylbenzene) (the following Reaction Scheme 3), the xylene yield is increased and the benzene yield is reduced. Also, the result of increasing the amount of trimethylbenzenes (C ₉ aromatic hydrocarbons) contained in the hydrotreated C ₁₀ ⁺ heavy aromatic by a hydrogenolysis reaction can also be explained by the following reaction formula (3). (C ₉ aromatic hydrocarbons) by the following reaction formulas (3-1) and (3-2).

In addition, according to Experimental Example 3 of the present invention, as shown in Table 5 and Table 6, other C ₁₁ and C ₁₁ ⁺ aromatic hydrocarbons, which are contained in the reactants in a considerable amount, It can be seen that it is converted to light aromatic hydrocarbons in the range of C ₆ -C ₉ .

[Reaction Scheme 3]

Therefore, according to various embodiments of the present invention, by using a catalyst for hydrocracking reaction according to an embodiment of the present invention, BTX is included from by-products of refinery and petrochemical processes having high content of polycyclic aromatic hydrocarbons such as naphthalene and alkyl-naphthalene It is possible to obtain an effect of obtaining xylene at a high yield in a high-cost light aromatic hydrocarbon, particularly BTX.

Claims

A catalyst for hydrocracking reaction for producing a light aromatic hydrocarbon having an increased xylene content from polycyclic aromatic hydrocarbons,
(B) a polycyclic aromatic compound containing a tetralin, a methyl-tetralin or a C ₁₀ aromatic isomer, including (A) a zeolitic carrier in which a Ni metal is in the form of pure metal, A catalyst for hydrocracking reaction for producing light aromatic hydrocarbons with increased xylene content from hydrocarbons.

The method according to claim 1,
Wherein the zeolite-based carrier further comprises (A) a Group IV metal. The catalyst for hydrocracking reaction according to claim 1, wherein the zeolite carrier comprises a Group IV metal.

The method according to claim 1,
(i) when the Ni metal is solely carried on the zeolitic carrier, the Ni metal is contained in an amount of 1.1-4.9 wt% based on the total weight of the catalyst for hydrocracking reaction of hydrocarbons. And a catalyst for hydrocracking reaction for producing the increased light aromatic hydrocarbons.

3. The method of claim 2,
(ii) Ni metal and a Group IV metal are contained in the zeolitic carrier in an amount of 1.1 to 7 wt% based on the total weight of the catalyst for hydrocracking reaction of hydrocarbon, respectively To produce a light aromatic hydrocarbon having an increased xylene content from polycyclic aromatic hydrocarbons.

3. The method of claim 2,
(ii) the Ni metal and the Group IV metal are contained in the zeolitic carrier in an amount of 2-5: 3-5 by weight, and the xylene content And a catalyst for hydrocracking reaction for producing the increased light aromatic hydrocarbons.

3. The method of claim 2,
Wherein the Group IV metal is at least one selected from the group consisting of Sn, Ge, and Pb. The catalyst for hydrocracking reaction according to claim 1,

The method according to claim 1,
Wherein the zeolite carrier is at least one selected from the group consisting of zeolite Beta, ZSM-5, and mordenite. The catalyst for hydrocracking reaction according to claim 1, wherein the zeolite carrier is at least one selected from zeolite Beta, ZSM-5 and mordenite.

The method according to claim 1,
Wherein the zeolite-based carrier is a mixture of SiO ₂ and Al ₂ O ₃ in a molar ratio of 15-40: 1, wherein the zeolite carrier is a hydrocarbons catalyst.

delete

The method according to claim 1,
The C ₁₀ aromatic isomers include 1,2,4,5-tetramethylbenzene (durene), 1,2,3,5-tetramethylbenzene (isodurene) and 1,2,3,4-tetramethylbenzene Wherein the catalyst comprises at least one tetramethylbenzene isomer selected from the group consisting of a polycyclic aromatic hydrocarbon and an aromatic hydrocarbon.

(a) preparing an aqueous solution by dissolving Ni metal alone in the form of pure metal, which is not in the form of a metal sulfide, or Ni metal and a metal precursor of Group IV together in distilled water or hydrochloric acid aqueous solution;
(b) impregnating the zeolite-based catalyst with the aqueous solution obtained in step (a); And
(c) drying the support obtained in the step (b) and calcining the support in an oven in which oxygen flows, thereby obtaining a zeolite catalyst containing the Ni metal alone or the Ni metal and the Group IV metal together; To produce a light aromatic hydrocarbon having an increased xylene content from polycyclic aromatic hydrocarbons.

Within the reactor
(1) drying or reducing a catalyst for hydrocracking reaction of polycyclic aromatic hydrocarbons;
(2) lowering the reactor temperature to 150 ° C or less, adjusting the pressure to 400-1500 psig, and adjusting the hydrogen flow rate to 20-100 cc / min · g-cat;
(3) flowing a reaction product containing polycyclic aromatic hydrocarbons and tetralin, methyl-tetralin or a C ₁₀ aromatic isomer at a flow rate of 0.3-3.3 cc / min · g-cat;
(4) recovering the reaction liquid product in a gas / liquid separator by raising the temperature of the reactor to 350 to 450 ° C,
Wherein the catalyst comprises (A) a zeolite-based carrier on which Ni metal in the form of a pure metal is supported rather than in the form of a metal sulfide, (B) a polycyclic aromatic hydrocarbon Way.