KR102063798B1 - Selective hydrotreating method for preparing light aromatic hydrocarbons from polycyclic aromatic hydrocarbons with high nitrogen content - Google Patents

Abstract

The present invention relates to a selective hydrogenation process for producing light aromatic hydrocarbons from polycyclic aromatic hydrocarbons having a high nitrogen content, and more particularly, by selectively hydrogenating polycyclic aromatic hydrocarbons, which are by-products of refinery processes having a high nitrogen content. 1) effectively lowering the nitrogen content, and 2) a technique that provides the effect of the conversion of the polycyclic aromatic compound of 2-Ring or higher to 1-ring aromatic with high selectivity. This has the effect of extending the catalyst life of the subsequent hydrocracking process and improving the yield of C ₆ -C ₉ light aromatic hydrocarbons.

Description

Selective hydrotreating method for preparing light aromatic hydrocarbons from polycyclic aromatic hydrocarbons with high nitrogen content}

The present invention relates to a selective hydrogenation process for producing light aromatic hydrocarbons from polycyclic aromatic hydrocarbons having a high nitrogen content, and more particularly, by selectively hydrogenating polycyclic aromatic hydrocarbons, which are by-products of refinery processes having a high nitrogen content. 1) effectively lowering the nitrogen content, and 2) a technique that provides the effect of the conversion of the polycyclic aromatic compound of 2-Ring or higher to 1-ring aromatic with high selectivity. This has the effect of extending the catalyst life of the subsequent hydrocracking process and improving the yield of C ₆ -C ₉ light aromatic hydrocarbons.

In the oil refining and petrochemical processes, many polycyclic aromatic hydrocarbons fractions containing high amounts of naphthalene and alkyl-naphthalene are being produced. Representative examples include pyrolysis fuel oil (PFO) from the Naphtha Cracking Center (NCC) process, C ₁₀ + heavy aromatics from the para-xylene process, and light cycle oil (LCO) from the fluid catalytic cracker (FCC) process. Among them, FCC LCO, which has the largest amount of Busan, has the boiling point range of light fuel oil (eg diesel), but it is very limited to be used as light fuel oil because of its high aromatic content and low cetane number. Therefore, the majority of FCC LCO is used to control the viscosity of heavy fuel oil for ships, and the use of LCO used to control the viscosity of heavy fuel oil will also decrease significantly in the long term due to the increase in eco-friendly vessels and the use of clean fuel and power generation system. It is expected. Therefore, there is a need for development of a catalytic process capable of converting polycyclic aromatic hydrocarbons including FCC LCO into high value products. In particular, high-addition of polycyclic aromatic hydrocarbons with high content of naphthalenes such as FCC LCO includes 1) diesel having high cetane number (CN) or 2) C ₆ -C containing BTX (benzene, toluene, xylenes). Two options for converting to the ₉ range of light aromatic hydrocarbons can be considered. Reaction pathways for the two approaches are shown below in [Reaction Scheme 1] and [Reaction Scheme 2] using naphthalene as an example. The hydrogen consumption required for obtaining the respective products is indicated in parentheses.

Scheme 1

In [Scheme 1], in order to convert naphthalene into a diesel component having a high CN (Cetane Number), the naphthalene is completely hydrogenated with decalin (HYD, Hydrogenation), and one or two lead ring are selectively ring opened (RO). Should be converted to maintain total carbon numbers. At least 6 moles or more of hydrogen are required to obtain components with a CN of 40 or greater in naphthalene.

Scheme 2

In order to convert naphthalene into a high value light aromatic hydrocarbon containing BTX, as shown in [Scheme 2], only one benzene ring is selectively hydrogenated among two benzene rings of naphthalene to have a naphthene ring. Converted to tetralin, the naphthenic ring of tetralin can be degraded by successive hydrocracking reactions (HYC, Hydrocracking) to produce BTX. In this case, at least 4 moles of hydrogen are required to obtain BTX in naphthalene, which results in less hydrogen consumption than in the case of diesel with high CN.

Meanwhile, in [Scheme 1] and [Scheme 2], the reaction between naphthalene ↔ tetralin and tetralin ↔ decalin are all reversible reactions determined by thermodynamic equilibrium and are activated by metal catalysts. The hydrogenation reaction of tetralin in naphthalene is a strong exothermic reaction with reduced total moles. 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, if the reaction temperature is high and the hydrogen pressure is low, the dehydrogenation reaction in which tetralin is converted back to naphthalene is superior, resulting in low conversion of naphthalene and low yield of tetralin. Hydrogenation of decalin in tetralin is also advantageous at higher pressures and at lower temperatures.

In the scheme 2, since hydrocracking reaction (HYC) is generally performed at high temperature and high pressure, tetralin may be converted back to naphthalene by dehydrogenation reaction, in which case the yield of light aromatic hydrocarbon containing BTX is lowered. . In addition, if the hydrogenation activity of the hydrocracking catalyst is excessively high and the benzene ring of tetralin is further hydrogenated to generate a lot of decalin, decalin is decomposed into LPG and naphtha by hydrocracking reaction (HYC) The yield of light aromatic hydrocarbons containing BTX is lowered and the hydrogen consumption is higher.

Therefore, in order to obtain the maximum yield of light aromatic hydrocarbon containing high valued BTX, in the hydrocracking reaction of tetralin, reconversion of tetralin to naphthalene (dehydrogenation reaction) and hydrogenation reaction of tetralin to decalin It must be restrained. To this end, there is a need for a hydrocracking catalyst that maximizes the yield of light aromatic hydrocarbons including BTX by minimizing the generation of LPG and naphtha by appropriately adjusting the hydrogenation function of the catalyst for hydrocracking reaction.

On the other hand, FCC LCO, which has a high content of polycyclic aromatic hydrocarbons in naphthalenes, has a high content of nitrogen compounds of several hundreds to thousands of ppm. In order to prepare a high valued light aromatic hydrocarbon containing BTX from FCC LCO as described in [Scheme 2], first, hydrotreating the FCC LCO (HDT, Hydrotreating), and then hydrocracking on a catalyst including an acid catalyst such as zeolite ( HYC, Hydrocracking). Nitrogen compounds contained in FCC LCO poison the hydrocracking catalyst containing acid function, so they should be almost completely removed by hydrodenitration (HDN) in the previous hydrotreating process. High hydrogen pressure is required to achieve a high hydrodenitrification effect, which lowers the total nitrogen compound content to several ppm or less, under which condition naphthalene can be fully hydrogenated to decalin, as shown in the above Reaction Scheme 2, which is followed by subsequent hydrocracking. The yield of light aromatic hydrocarbons including BTX obtained in the reaction can be lowered.

Accordingly, the present inventors, in order to obtain a high yield of light aromatic hydrocarbon containing high value added BTX from light cycle oil (LCO) of the FCC (Fluid Catalytic Cracker) process with a high nitrogen compound content, 1) with a high hydrodesulfurization effect 2 The present invention has been completed in view of the need for a hydrogenation method in which a polycyclic aromatic compound is not completely hydrogenated and is converted into a 1-ring aromatic compound with high yield and selectivity.

Patent Documents 1. Korean Unexamined Patent Publication No. 10-2013-0055047

The present invention has been devised in view of the above problems, and an object of the present invention is to provide a high effect of hydrodenitrification conversion conditions for polycyclic aromatic hydrocarbons having high nitrogen content, such as by-products from oil refining and petrochemical processes such as LCO of FCC process. In order to provide a selective hydrogenation process technology capable of converting a polycyclic aromatic compound into a 1-ring aromatic compound in high yield and selectivity.

One aspect of the present invention for achieving the above object is a pretreatment step of physically removing a portion of the high boiling fraction in the polycyclic aromatic compound; And a step of hydrotreating the pretreated polycyclic aromatic compound on a hydrogenation catalyst. The method relates to a selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds.

Another aspect of the present invention comprises the steps of (a) dissolving Group VIB and Group VIII metal precursors in distilled water to prepare a metal precursor aqueous solution; (b) impregnating the aqueous metal precursor solution obtained in step (a) into gamma alumina; And (c) drying the gamma alumina in step (b) and calcining in an oxygen-flowing oven to obtain a hydrotreating catalyst comprising a Group VIB and Group VIII metal together. A method for producing a selective hydrotreating catalyst of this highly polycyclic aromatic compound.

Another aspect of the present invention is a selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds using a hydrogenation catalyst prepared by the production method according to the present invention, in a reactor, (1) the hydrogenation treatment Drying the catalyst; (2) after raising the reactor temperature to 400-500 ° C., the pressure was adjusted to 400-1500 psig, and sulfiding the hydrotreating catalyst under a gas stream comprising hydrogen; (3) lowering the reactor temperature below 120 ° C., adjusting the pressure to 500 to 1600 psig, and adjusting the hydrogen flow rate to 30 to 100 cc / min · g-cat; (4) flowing polycyclic aromatic hydrocarbons at a flow rate of 0.01 to 3.3 cc / min · g-cat; And (5) increasing the reactor temperature to 350 to 400 ° C., and then recovering the reaction liquid product in a gas / liquid separator, wherein the polycyclic aromatic compound having a high content of nitrogen compound is selected. It relates to a hydrogenation treatment method.

According to the present invention, a selective hydrogenation process of a polycyclic aromatic hydrocarbon having a high nitrogen content has a high removal efficiency of nitrogen compounds under hydrogenation conditions with low operating severity, and a high yield and selection of a polycyclic aromatic compound having at least two rings. Road to monocyclic aromatic (1-Ring aromatic) compounds can be provided.

1 is a light aromatic hydrocarbon containing BTX from a selective hydrotreating process (process including C1 and RP1) and hydrocracking process from a polycyclic aromatic hydrocarbon having a high content of nitrogen compounds according to one embodiment of the present invention; [F: polycyclic aromatic compound with high nitrogen compound content (reactant), C1: distillation column, D1: high boiling point nitrogen compound and reactant with reduced tricyclic aromatic compound content, D2: high boiling point removed from C1 Oil, RP1: hydrotreating process, RP2: hydrocracking process, P1: LPG product, P2: Naphtha (Gasoline) product, P3: C ₆ -C ₉ aromatic product, P4: C ₁₀ + aromatic product (P4 is ultra low sulfur (ULSD) or can be reused as RP2 reactant).
2 is a graph showing the content of nitrogen compounds in the product according to the Di + ring aromatic conversion rate (see Equation 1) according to the Examples and Comparative Examples of the present invention.
3 is a graph showing the selectivity of Mono-ring aromatics in the product according to Di + ring aromatic conversion (see Equation 1) according to Examples and Comparative Examples of the present invention (see Equation 2 below).

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

Techniques for converting polycyclic aromatic hydrocarbons having two or more benzene rings, such as naphthalene and alkyl-naphthalene, included in by-products of refinery and petrochemical processes into high valued light aromatic hydrocarbons, including BTX, have been proposed. There is a lack of technology for the selective hydrogenation process to increase the efficiency of removing nitrogen compounds from polycyclic aromatic compounds with high content at low operating severity and to convert bicyclic or higher polycyclic aromatic compounds into monocyclic aromatic compounds with high yield and selectivity.

Meanwhile, "selective hydrogenation of a polycyclic aromatic hydrocarbon having a high nitrogen compound content" refers to selective hydrogenation of some aromatic compounds of a polycyclic aromatic hydrocarbon under conditions of high nitrogen compound removal efficiency, and naphthalene as an example of polycyclic aromatic hydrocarbons. For example, as shown in [Scheme 3], naphthalene is a reaction in which only one benzene ring is selectively hydrogenated among two benzene rings constituting naphthalene when hydrogen is added in the presence of a catalyst. Can be defined. Through successive hydrocracking reactions, the lead senchol ring of tetralin can be ring-opened and decomposed to yield light aromatic hydrocarbons, including BTX.

Scheme 3

According to the present invention, the refinery and petrochemical process by-products containing polycyclic aromatic hydrocarbons having a high content of nitrogen compounds are subjected to hydrotreating to carry out two or three or more benzene rings such as naphthalene, alkyl-naphthalene and anthracene. It was found that the hydrocarbons were selectively converted to aromatic hydrocarbons having one benzene ring.

Particularly, among the polycyclic aromatic compounds having a high content of nitrogen compounds, high boiling point nitrogen compounds having low hydrodenitrification reactivity and high boiling point polycyclic aromatic fractions more than tri-ring which are difficult to convert to light aromatic hydrocarbons such as BTX are simplified. By lowering it in advance through continuous distillation, it is possible to achieve high nitrogen compound removal efficiency without increasing the operating severity of the hydrotreating process, and to prevent the partial hydrogenation of some of the polycyclic aromatic compounds in the process so that BTX and The same light aromatic hydrocarbons can be obtained in high yields.

One aspect of the invention, the pre-treatment step of physically removing a portion of the high boiling fraction in the polycyclic aromatic compound; And a step of hydrotreating the pretreated polycyclic aromatic compound on a hydrogenation catalyst. The method relates to a selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds.

According to one embodiment of the invention, the pretreatment step is a continuous distillation process; The boiling point of the pretreated polycyclic aromatic compound may be less than 360 ° C.

If the end boiling point of the pre-treated polycyclic aromatic compound exceeds 360 ℃, the conversion rate of the polycyclic aromatic hydrocarbon having a bicyclic, tricyclic or higher benzene ring is significantly lowered and the nitrogen compound content in the product is very high, dozens of ppm or more. It was.

According to another embodiment of the present invention, the polycyclic aromatic hydrocarbon may have a nitrogen compound content of 0.01 to 0.12% by weight.

According to another embodiment of the present invention, the hydrotreating catalyst may include (i) a metal oxide-based support, and (ii) a Group VIB and Group VIII metal supported on the support, and as a binder, pseudo- It may further comprise Pseudo Boehmite.

According to another embodiment of the present invention, the content of the Group VIB metal and Group VIII metal may be 5 to 25% by weight and 2 to 6% by weight based on the total weight of the hydrotreating reaction catalyst, respectively.

According to another embodiment of the present invention, the Group VIB metal is one selected from Mo and W; The Group VIII metal may be at least one selected from Ni and Co.

According to another embodiment of the invention, the Group VIB metal and Group VIII metal is preferably in the form of sulfides.

According to another embodiment of the present invention, the metal oxide carrier may be gamma alumina.

According to another embodiment of the invention, on all catalysts used for the hydrotreating, a portion of the high boiling fraction of the refinery and petrochemical process by-products containing polycyclic aromatic hydrocarbons with a high nitrogen compound content is removed in advance and the hydrotreating reaction is carried out. It was confirmed that the removal rate of the nitrogen compound was 98% or more by proceeding. Otherwise, when directly hydroprocessing polycyclic aromatic hydrocarbons having a high content of nitrogen compounds, it was confirmed that the amount of monocyclic aromatic compounds was decreased due to the thermodynamically disadvantageous hydrogenation reaction at the time of increasing the temperature in order to increase the removal rate of the nitrogen compounds. In this case, there is a problem in that the lifetime of the catalyst is shortened by increasing the operating temperature by increasing the reaction temperature. In addition, in the case of direct hydrogenation of polycyclic aromatic hydrocarbons with high nitrogen compound content without removing some of the high-boiling fractions in advance, if hydrogen pressure is increased to increase the removal rate of nitrogen compounds, some of the polycyclic aromatic compounds are completely hydrogenated, resulting in a final monocyclic aromatic compound. It is expected that the yield will be reduced.

In particular, although not explicitly described in the following Examples or Comparative Examples, in the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds according to the present invention, for various types of hydrogenation catalysts, The hydrotreating according to Experimental Example 1 was carried out by changing the conditions, the end point range of the pretreated polycyclic aromatic, the content of the metal on the hydrotreated catalyst, the form of the hydrotreated catalyst and the content of the nitrogen compound in the polycyclic aromatic compound. After performing it once, it was confirmed whether the metal supported on the catalyst is lost.

As a result, unlike other types of hydrotreating catalysts, forms and other numerical ranges, no loss of metal supported on the hydrotreating catalyst was observed even after 300 times of hydrotreating when all of the following conditions were satisfied.

(i) the pretreatment step is a continuous distillation step, (ii) the boiling point of the pretreated polycyclic aromatic compound is less than 360 ° C., (iii) the polycyclic aromatic compound has a nitrogen compound content of 0.01 to 0.12% by weight, and (i) the hydrogenation catalyst (A) Gamma alumina, and (B) Ni and Mo supported on the gamma alumina, (iii) The content of Ni and Mo is 2 to 4% by weight and 7 to 12%, respectively, based on the total weight of the hydrotreating catalyst. % By weight, (iii) Ni and Mo are sulfide forms.

However, when any of the above conditions were not satisfied, it was confirmed that after the hydrotreating 300 times, the loss of the hydrotreating catalyst appeared remarkably.

Another aspect of the present invention comprises the steps of (a) dissolving Group VIB and Group VIII metal precursors in distilled water to prepare a metal precursor aqueous solution; (b) impregnating the aqueous metal precursor solution obtained in step (a) into gamma alumina; And (c) drying the gamma alumina in step (b) and calcining in an oxygen-flowing oven to obtain a hydrotreating catalyst comprising a Group VIB and Group VIII metal together. A method for producing a selective hydrotreating catalyst of this highly polycyclic aromatic compound.

The drying of step (c) is carried out at room temperature for 1 to 10 hours, preferably 2 to 8 hours, more preferably 4 to 7 hours, then 1 to 20 hours at 60 to 100 ℃, preferably 5 To 18 hours, more preferably 8 to 14 hours.

As the carrier, it is preferable to use gamma alumina having almost no acid point as described above.

In particular, although not explicitly described in the following Examples, Comparative Examples, etc., in the method for producing a selective hydrogenation catalyst of a polycyclic aromatic compound having a high content of nitrogen compounds according to the present invention, hydrogenation is carried out for various kinds of supported metals. By varying the content of the metal on the treated catalyst, the drying conditions of step (c) and the firing conditions of step (c), it is determined whether or not the metal supported on the catalyst is lost after performing the hydrogenation treatment 300 times according to Experimental Example 1. Confirmed.

As a result, unlike other types of hydrotreating catalysts, forms and other numerical ranges, no loss of metal supported on the hydrotreating catalyst was observed even after 300 times of hydrotreating when all of the following conditions were satisfied.

(i) Group VIB and Group VIII metals are Mo and Ni, and (ii) the Ni and Mo contents are 2-4 wt% and 7-12 wt%, respectively, based on the total weight of the hydrotreating catalyst, (iii) (c) ) Drying is carried out at room temperature for 4 to 7 hours, then at 60 to 100 ℃ for 8 to 14 hours, (iii) firing of step (c), the first heat treatment between 100 to 300 ℃ at room temperature A first heat treatment step of raising the temperature to 8 to 12 ° C./min; And a second heat treatment step of raising the temperature at 1 to 7 ° C./min from the first heat treatment temperature to a temperature between 400 and 600 ° C.

However, when any of the above conditions were not satisfied, it was confirmed that after the hydrotreating 300 times, the loss of the hydrotreating catalyst appeared remarkably.

Another aspect of the present invention is a selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds using a hydrogenation catalyst prepared by the production method according to the present invention, in a reactor, (1) the hydrogenation treatment Drying the catalyst; (2) after raising the reactor temperature to 400-500 ° C., the pressure was adjusted to 400-1500 psig, and sulfiding the hydrotreating catalyst under a gas stream comprising hydrogen; (3) lowering the reactor temperature below 120 ° C., adjusting the pressure to 500 to 1600 psig, and adjusting the hydrogen flow rate to 30 to 100 cc / min · g-cat; (4) flowing polycyclic aromatic hydrocarbons at a flow rate of 0.01 to 3.3 cc / min · g-cat; And (5) increasing the reactor temperature to 350 to 400 ° C., and then recovering the reaction liquid product in a gas / liquid separator, wherein the polycyclic aromatic compound having a high content of nitrogen compound is selected. The present invention relates to a hydrotreating process, and through the hydrotreating process, polycyclic aromatic hydrocarbons having two, three or more benzene rings can be converted into monocyclic aromatic hydrocarbons, and the content of nitrogen compounds can be reduced.

According to one embodiment of the present invention, the sum of the content of naphthalene and methyl-naphthalene may be 0.05 to 50% by weight based on the total weight of the polycyclic aromatic hydrocarbon.

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

Preparation Example 1 Preparation of LCO (Light Cycle Oil) Reactant

LCO used in the Examples and Comparative Examples of the present invention was prepared as follows.

(1) LCO 1: LCO 1 represents LCO taken from a Fluid Catalytic Cracker (FCC) process,

(2) LCO 2: LCO 2 was distilled LCO 1 to remove a portion of the high boiling fraction, but the end point (AST) below 340 ℃ according to ASTM D-86,

(3) LCO 3: LCO 3 distilled LCO 1 to remove a portion of the high boiling fraction, but the end point was lower than 310 ℃ based on ASTM D-86.

Table 1 shows the results of the analysis of LCO 1 to LCO 3, LCO 2 and LCO 3 has no significant difference in the total aromatic content compared to LCO 1, but the nitrogen compound content and the three-ring or more polycyclic aromatic content is significantly reduced You can check it.

LCO LCO 1
(Full range) LCO 2
(IBP ~ 340 ℃) LCO 3
(IBP ~ 300 ℃) Yield, wt% 100 77.2 57.6 API 15.7 18.3 19.9 Density (@ 15 ℃) 0.9607 0.9441 0.9341 Sulfur, wt% 0.30 0.21 0.14 Nitrogen, wtppm 570 290 190 Cetane Index 24.2 22.2 20.0 Aromatics,
wt% Mono 19.2 22.4 27.3 Di 54.8 54.4 53.9 Tri + 8.5 2.6 0.6 Nonaromatics 17.5 20.6 18.2 Total 100 100 100

Preparation Example 2 Preparation of Catalyst

The preparation method of the catalysts used in the Examples and Comparative Examples of the present invention is as shown below.

(1) Catalyst 1: Ni (3) -Mo (8) -S / γ-Al ₂ O ₃ Catalyst manufacturing

Gamma-alumina (γ-Al ₂ O ₃ ) powder was impregnated with an aqueous solution in which the nickel precursor was dissolved and an aqueous solution in which the molybdenum precursor was dissolved, thereby preparing a catalyst such that the nickel and molybdenum contents were 3% by weight and 8% by weight, respectively. It was. Nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ · 6H ₂ O, hereinafter “NNH”) was used as the nickel precursor used in the preparation, and ammonium molybdate tetrahydrate (H ₂₄ Mo was used as the molybdenum precursor. a _{7 N 6 O 24 · 4H 2} O, or less "AMT") was used.

An aqueous solution prepared by dissolving NNH (0.334 g) and AMT (0.331 g) in distilled water (2.5 ml) was impregnated with gamma-alumina (γ-Al ₂ O ₃ ) powder (2.0 g) dried overnight at 80 ° C. in air. Then, the mixture was dried at room temperature for 5 hours and dried overnight at 80 ° C. Then, it heated up at 10 degree-C per minute in air, hold | maintained at 150 degreeC for 1 hour, heated up at 5 degree-C per minute at 150 degreeC, and baked at 500 degreeC for 3 hours.

In Ni (3) -Mo (8) -S / γ-Al ₂ O ₃ , the numbers in parentheses represent the weight percentages of Ni and Mo based on the total weight of the catalyst.

(2) Catalyst 2: CO (3) -Mo (8) -S / γ-Al ₂ O ₃ Catalyst manufacturing

A catalyst was prepared in the same manner as in Catalyst 1, 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. .

(3) Catalyst 3: Ni (3.5) -W (24) -S / γ-Al ₂ O ₃ Catalyst manufacturing

A catalyst was prepared in the same manner as in Catalyst 1, but tungsten was used instead of molybdenum as the metal component. Nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ · 6H ₂ O, hereinafter “NNH”) was used as the nickel precursor, and ammonium metatungstate ((NH ₄ ) ₆ H ₂ W ₁₂ O was used as the precursor of tungsten. ₄₀ · 5H ₂ O) was used. The impregnated catalyst was dried at room temperature for 5 hours, further dried overnight at 80 ° C., then heated to 2.5 ° C. per minute in air, and calcined at 500 ° C. for 3 hours.

Experimental Example 1: Hydrogenation Reaction of Light Cycle Oil (LCO)

LCO 1 to 2 prepared from Preparation Example 1 were used as a reactant, and the catalysts prepared from Preparation Example 2 were dried and pretreated in the following manner, followed by a hydrotreating reaction, and the results are shown in Table 2 below. It was.

In order to further explain the principle of the present invention, the catalysts prepared from Preparation Example 2 were molded to a size of 250 to 500 μm. 0.90 g of the shaped catalyst was charged to a fixed bed flow reactor and the Ni-Mo, Co-Mo and Ni-W supported catalysts were dried at 150 ° C. under argon flow (30 cc / min) for 1 hour, followed by a pressure of 460 psi hydrogen flow ( Under a flow rate of 0.198 cc / min at a flow rate of 0.198 cc / min under a flow rate of 0.198 cc / min under 100 cc / min) The temperature was raised at a rate of ° C / min and maintained at 400 ° C for 2 hours to sulfide.

After the sulfidation of the catalyst, the reactor temperature was lowered to 120 ° C. at a rate of 2.5 ° C./min, the conditions were changed to a pressure of 882 psig and a hydrogen flow rate of 30 cc / min · g-cat, and the reaction mass was 0.011 cc / min · g- The flow rate was cat. LCO 1 to LCO 2 were used as the reactants, and the hydrogen / LCO molar ratio was 30.0. Reactant flow rate corresponds to Weight Hourly Space Velocity (WHSV) = 0.7 h ^-1 based on LCO flow rate and catalyst mass. After the reactor temperature was raised to the reaction temperature and the steady state was reached, the reaction liquid product was recovered at the bottom of the gas / liquid separator, and the components of the liquid product were confirmed by GC-FID analysis and GC / MS analysis. The performance of the catalyst was confirmed by analyzing the content of Mono (monocyclic), Di (bicyclic) and Tri + (more than tricyclic) Aromatics (aromatic) content, sulfur compound and nitrogen compound in the following hydrotreating reaction products. In addition, as shown in Equation 1, it was confirmed through the conversion rate of bicyclic, polycyclic aromatic hydrocarbons having three or more benzene rings and the selectivity of monocyclic aromatic as shown in Equation 2 below.

[Equation 1]

Di + ring aromatic conversion (%) = [(Di + ring aromatic content in the reactants, wt%)-(Di + ring aromatic content in the liquid products, wt%)] / (Di + ring aromatic content in the reactants, wt %) × 100

[Equation 2]

Mono-ring aromatic selectivity (%) = (mono-ring aromatic content in the liquid product, wt%) / (total aromatic content in the liquid product, wt%) x 100

Example 1 Hydrotreating of LCO 2 on Catalyst 1

Using the LCO 2 prepared from Preparation Example 1 as a reactant, using the catalyst 1 prepared in Preparation Example 2 was dried and pretreated in the same manner as in Experimental Example 1 and then subjected to a hydrotreating reaction.

Example 2: Hydrotreating of LCO 2 over Catalyst 2

The experiment was carried out in the same manner as in Example 1, but using Catalyst 2 prepared from Preparation Example 2.

Example 3: Hydrotreating of LCO 2 over Catalyst 3

The experiment was carried out in the same manner as in Example 1, except that Catalyst 3 prepared from Preparation Example 2 was used.

Comparative Example 1: Hydrotreating of LCO 1 on Catalyst 1

The experiment was conducted in the same manner as in Example 1, except that LCO 1 prepared from Preparation Example 1 was used as a reactant, and Catalyst 1 prepared from Preparation Example 2 was used.

Comparative Example 2: Hydrotreating of LCO 1 on Catalyst 2

The experiment was conducted in the same manner as in Comparative Example 2, but Catalyst 2 prepared from Preparation Example 2 was used.

Comparative Example 3: Hydrotreating of LCO 1 on Catalyst 3

The experiment was conducted in the same manner as in Comparative Example 2, but Catalyst 3 prepared from Preparation Example 2 was used.

Temperature
(℃) Aromatics, wt% Di + conversion rate,% Sulfur compound (wtppm) Nitrogen Compound (wtppm) Mono Di Tri + Example 1 350 79.4 3.4 - 94.0 20 3 375 76.3 2.4 - 95.8 12 One Example 2 350 79.1 5.0 - 91.2 49 2 375 77.4 4.6 - 91.9 22 2 Example 3 350 75.4 3.0 - 94.7 12 3 375 69.4 2.3 - 96.0 3 4 Comparative Example 1 350 80.5 7.5 0.5 87.4 87 36 375 77.9 6.6 0.5 88.8 11 13 Comparative Example 2 350 75.7 12.6 1.0 78.5 428 143 375 78.3 9.6 0.7 83.7 56 59 Comparative Example 3 350 80.1 7.6 0.5 87.2 244 68 375 78.8 6.0 0.4 89.9 53 25

As shown in the LCO hydrogenation reaction results in Table 2, LCO HDT (Hydrotreating) analysis results according to Examples (Examples 1 to 3) of the present invention is compared with the analysis results according to Comparative Examples (Comparative Examples 1 to 3) When viewed, the amount of mono-ring aromatics was not significantly different, but the conversion of polycyclic aromatic hydrocarbons having Di and Tri + rings was higher in Examples, and the content of sulfur and nitrogen compounds was also lower. In particular, according to the results according to Examples 1 to 3, the nitrogen compound content in the product was very low at less than 5 ppm under conditions of high Di + ring aromatic conversion (see FIG. 2). The aromatic content and selectivity were slightly lower (see Figure 3). In Comparative Examples 1 to 3 using LCO 1 as a reactant, the content of the nitrogen compound in the product was several tens of ppm or more and the mono-ring aromatic selectivity was also low, which is considered to be disadvantageous (see FIG. 3).

Therefore, in order to obtain a high yield of light aromatic hydrocarbons including BTX from polycyclic aromatic hydrocarbons having a high nitrogen compound content, high nitrogen compound removal efficiency and selective hydrogenation of polycyclic aromatic compounds to monocyclic aromatic compounds are required in the hydrotreating process. For this purpose, it can be confirmed that a method of removing the high boiling point nitrogen compound having low denitrification reactivity and the high boiling point aromatic component which requires excessive hydrogen consumption in the LCO having a high nitrogen compound prior to the hydrotreating reaction is very effective. .

Claims (13)

A pretreatment step of physically removing a portion of the high boiling fraction from a light cycle oil (LCO) including a polycyclic aromatic compound having a nitrogen compound content of 0.01 to 0.12 wt%; And a step of hydrotreating the pretreated polycyclic aromatic compound on a hydrogenation catalyst, the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compound,
The pretreatment step is a continuous distillation process,
Selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compound, characterized in that the longitudinal boiling point of the pre-treated polycyclic aromatic compound is less than 360 ℃. delete delete The method of claim 1,
The hydrogenation catalyst comprises (i) a metal oxide-based support, and (ii) a group VIB and group VIII metal supported on the support, wherein the hydrogenation catalyst selectively hydrogenates polycyclic aromatic compounds having a high content of nitrogen compounds. Treatment method. The method of claim 4, wherein
The selective hydrogenation of the polycyclic aromatic compound having a high content of nitrogen compound, characterized in that the content of the Group VIB metal and Group VIII metal is 5 to 25% by weight and 2 to 6% by weight relative to the total weight of the hydrotreating catalyst, respectively. Treatment method. The method of claim 4, wherein
The Group VIB metal is at least one selected from Mo and W;
The group VIII metal is one or more selected from Ni and Co, characterized in that the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds. The method of claim 4, wherein
The group VIB metal and group VIII metal is sulfide form, characterized in that the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds. The method of claim 4, wherein
The metal oxide-based support is gamma alumina, characterized in that the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds. The method of claim 1,
The pretreatment step is a continuous distillation process;
The boiling point of the pretreated polycyclic aromatic compound is less than 360 ° C .;
The polycyclic aromatic compound has a nitrogen compound in an amount of 0.01 to 0.12 wt%;
The hydrotreating catalyst comprises (i) gamma alumina and (ii) Ni and Mo supported on the gamma alumina;
The content of Ni and Mo is 2 to 4% by weight and 7 to 12% by weight relative to the total weight of the hydrotreating catalyst;
The Ni and Mo is a sulfide form, characterized in that the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds. (a) dissolving Group VIB and Group VIII metal precursors in distilled water to prepare a metal precursor solution;
(b) impregnating the aqueous metal precursor solution obtained in step (a) into gamma alumina; And
(c) drying the gamma alumina in step (b) and calcining in an oven in which oxygen flows to obtain a hydrotreating catalyst comprising a Group VIB and Group VIII metal together; As a method for producing a selective hydrogenation catalyst of high polycyclic aromatic compounds,
Selective hydrogenation of a polycyclic aromatic compound having a high content of nitrogen compounds
A pretreatment step of physically removing a portion of the high boiling fraction from a light cycle oil (LCO) including a polycyclic aromatic compound having a nitrogen compound content of 0.01 to 0.12 wt%; And hydrotreating the pretreated polycyclic aromatic compound on a hydrotreating catalyst.
The pretreatment step is a continuous distillation process,
Method for producing a selective hydrogenation catalyst of a polycyclic aromatic compound having a high content of nitrogen compound, characterized in that the end point of the pre-treated polycyclic aromatic compound is less than 360 ℃. The method of claim 10,
The Group VIB and Group VIII metals are Mo and Ni, respectively;
The content of Ni and Mo is 2 to 4% by weight and 7 to 12% by weight relative to the total weight of the hydrotreating catalyst;
The drying of 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 firing of the step (c) may include a first heat treatment step of heating up at a temperature of 8 to 12 ° C./min from room temperature to a first heat treatment temperature between 100 to 300 ° C .; And a second heat treatment step of raising the temperature at 1 to 7 ° C./min from the first heat treatment temperature to a temperature between 400 and 600 ° C., wherein the selective hydrogenation of the polycyclic aromatic compound having a high nitrogen compound content is performed. Method for preparing a catalyst. The method of claim 1,
Hydrotreating the pretreated polycyclic aromatic compound on a hydrogenation catalyst, in the reactor,
(1) drying the hydrotreating catalyst;
(2) after raising the reactor temperature to 400-500 ° C., the pressure was adjusted to 400-1500 psig, and sulfiding the hydrotreating catalyst under a gas stream comprising hydrogen;
(3) lowering the reactor temperature below 120 ° C., adjusting the pressure to 500 to 1600 psig, and adjusting the hydrogen flow rate to 30 to 100 cc / min · g-cat;
(4) flowing the pretreated polycyclic aromatic compound at a flow rate of 0.01 to 3.3 cc / min g-cat; And
(5) increasing the reactor temperature to 350 to 400 ° C., and then recovering the reaction liquid product in a gas / liquid separator; selective hydrogenation of the polycyclic aromatic compound having a high nitrogen compound content Treatment method. The method of claim 12,
The polycyclic aromatic hydrocarbon has a sum of the content of naphthalene and methyl-naphthalene is 0.05 to 50% by weight relative to the total weight of the polycyclic aromatic hydrocarbon, the selective hydrogenation method of a polycyclic aromatic compound having a high content of nitrogen compounds.

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