KR100419288B1 - Method for preparing catalysts for dearomatization in distillate - Google Patents

Abstract

The present invention relates to a method for producing a catalyst for dearomatization of light oil (hydrocarbon compound having boiling point between 125 ° C and 400 ° C at atmospheric pressure), and more particularly, in a method for preparing catalyst for dearomatization of light oil. 0.1 to about 100 parts by weight of a mesoporous molecular sieve having a molar ratio of 30 to 300 SiO ₂ / Al ₂ O ₃ and a pore size of 25 to 50 GPa prepared by using a surfactant-type micelle template. Supporting 2.0 parts by weight; Shaping by adding 5 to 50 parts by weight of water-boehmite and 0.2 to 3.0 parts by weight of an acid solution to the supported mixture; And it relates to a method for producing a catalyst for dearomatization of light oil comprising the step of calcining the molded body at 300 to 600 ℃ for 4 to 6 hours.

The method for preparing a catalyst for dearomatization of light oil according to the present invention provides a catalyst capable of maximizing liquid yield and maintaining a high dearomatization activity by suppressing a cracking reaction.

Description

Method for preparing catalysts for dearomatization of light oils {Method for preparing catalysts for dearomatization in distillate}

The present invention relates to a process for preparing a catalyst for dearomatization of light oils (hydrocarbon compounds having boiling points between 125 ° C and 400 ° C at atmospheric pressure), more specifically platinum, palladium or mixtures thereof; Mesoporous molecular sieves; And a method for preparing a catalyst for dearomatization of light oil which can maintain high dearomatization activity using pseudo-boehmite and an acid solution.

With the development of various industries, there is an increasing demand for liquid saturated hydrocarbons with few aromatics such as aviation turbine oils, diesel oils, solvents and medical white oils, but the boiling point at atmospheric pressure distilled from crude oil is 125 Light oils having a temperature of ˜400 ° C. contain many aromatic compounds and require a process and a catalyst for removing them. In particular, diesel oil is a liquid hydrocarbon having a boiling point of 200 to 360 ° C. at atmospheric pressure, and when used as a fuel oil for automobiles, it causes air pollution. Contaminate Therefore, when the aromatic compound is removed, not only the source of environmental pollution can be eliminated, but also the fuel economy of the vehicle can be reduced by increasing the cetane number, and an excellent engine can be obtained. For example, naphthalene has a cetane number of 15, tetralin of 7, decalin of 48, butylcyclohexane of 50, and decane of 76. As a result, since the cetane number of the aromatic compound is small, in order to improve the performance of diesel oil, the aromatic compound has to be converted into a liquid hydrocarbon without a double bond through a hydrogenation reaction.

Recently, research on the dearomatization of light oils has been conducted by refineries in the US and Europe. US Patent No. 5,391,291 filed by Shell Oil is a zeolite Y having a molar ratio of SiO ₂ / Al ₂ O ₃ of 5 or more as a carrier. Disclosed are catalysts prepared using platinum and palladium as active metals. The catalyst according to the patent has an excellent dearomatization activity but has a disadvantage in that the yield of the liquid hydrocarbon is lowered because it is decomposed into a gaseous hydrocarbon. In addition, sodium ions are ion-exchanged in order to compensate for these disadvantages, but the process is not only complicated, but also lowers the dearomatization activity.

U.S. Patent No. 5,494,870, filed by Amoco, USA, uses a beta-zeolite as a carrier and platinum and palladium as active metals, and post-treatment of sodium ions to prevent decomposition of liquid hydrocarbons. It is starting. The process according to the patent not only involves a complicated process such as post-treatment of sodium ions, but also has a disadvantage of lowering dearomatization activity.

In addition, US Patent No. 5,225,383 and US Patent No. 5,346,874, filed by Amoco, disclose catalysts prepared using platinum, palladium as active metals, and modernite and borosilicate as carriers, respectively. The carriers rarely decompose liquid hydrocarbons, but have a disadvantage in that activity is less than zeolite Y having a SiO ₂ / Al ₂ O ₃ ratio of 5 or more in dearomatic performance.

Meanwhile, US Patent No. 5,500,109, filed by Mobil Oil, discloses a catalyst prepared by supporting nickel and tungsten as precursors on a zeolite Y carrier. The catalyst rarely causes side reactions and has a high resistance to sulfur components contained in light oil as impurities, but its dearomatization activity is lower than that of platinum or palladium.

In order to solve the above problems, the inventors have conducted extensive research, and the cracking reaction can be suppressed by using platinum, palladium or mixtures thereof and mesoporous molecular sieve to obtain high liquid hydrocarbon yield and excellent activity. In addition, a method of preparing a catalyst for dearomatization of a light oil capable of increasing activity by simultaneously performing a role of a carrier through heat treatment during the preparation of a catalyst using a sudo boehmite as a binder, and the present invention was completed based on this.

Accordingly, it is an object of the present invention to provide a process for preparing a catalyst for dearomatization of light oil which can maximize the yield of liquid and maintain a high dearomatization activity.

The method for preparing a catalyst according to the present invention for achieving the above object is a method for producing a catalyst for the dearomatization of light oil, prepared using a cationic surfactant micelle template 30 to 300 SiO ₂ / Al ₂ O ₃ Supporting 0.1 to 2.0 parts by weight of platinum, palladium or a mixture thereof in 100 parts by weight of the mesoporous molecular sieve having a molar ratio of 25 to 50 GPa; Shaping by adding 5 to 50 parts by weight of water-boehmite and 0.2 to 3.0 parts by weight of an acid solution to the supported mixture; And calcining the molded body at 300 to 600 ° C. for 4 to 6 hours.

Hereinafter, the present invention will be described in more detail.

According to the invention, most preferred are mesoporous materials as dearomatization catalyst carriers. Synthesis of the material has already been disclosed in Korean Patent No. 158759. The patent is a mesoporous crystalline compound having a uniform pore size and excellent thermal properties using all kinds of silica, and is composed of SiO ₂ alone, or has a molar ratio of SiO ₂ / Al ₂ O ₃ or SiO ₂ / TiO ₂ of 10 or more. A method for preparing a molecular sieve compound of mesoporous structure consisting of SiO ₂ / Al ₂ O ₃ (or TiO ₂ ) in a short time at low temperature and atmospheric pressure is disclosed.

The present invention prepared a mesoporous molecular sieve using a cationic surfactant micelle template according to the method disclosed in the Republic of Korea Patent No. 158759, the mesoporous molecular sieve of the present invention has a pore size of about 25 ~ 50Å in the mesoporous region It is not only uniform, but also has excellent thermal properties and has a large specific surface area of 500-1000m ² / g. The framework consists of SiO ₂ / Al ₂ O ₃ and consists of two dimensions like a hexagonal honeycomb structure. Has a scatter point This property increases the activity by causing the active ingredient to be well dispersed, and does not interfere with the diffusion of the reactants because the pore size is larger than that of the zeolite, which is a carrier of the catalyst already developed. In addition, since the acidity is not strong, the cracking reaction hardly occurs to increase the yield of light oil. The mesoporous molecular sieve may prepare a catalyst having excellent properties by controlling the molar ratio of SiO ₂ / Al ₂ O ₃ .

The molar ratio of SiO ₂ / Al ₂ O ₃ of the mesoporous molecular sieve according to the present invention is preferably 30 to 300. At this time, if the molar ratio of SiO ₂ / Al ₂ O ₃ is less than 30, the alumina is excessively present and most of the pores are present. It is present in the structure to form a tetrahedral structure to form a scattering point, but some of the octahedral structure in the amorphous state of the pore surface to block the active point of platinum or palladium to reduce the dearomatization activity. On the other hand, when the molar ratio of SiO ₂ / Al ₂ O ₃ exceeds 300, the number of acid points is small and the dearomatization activity is lowered. The molar ratio of SiO ₂ / Al ₂ O ₃ of the carrier according to the invention is most preferably 100 showing the greatest activity.

It is preferable to use platinum, palladium or a mixture thereof as the active ingredient of the present invention. However, when platinum and palladium are used together, it is more preferable to use a mixture thereof because it can reduce the deactivation of the catalyst by the sulfur component. On the other hand, it is also important to control the molar ratio of SiO ₂ / Al ₂ O ₃ of the mesoporous molecular sieve, but also a technique for dispersing platinum or palladium, which is an active ingredient, in a carrier. Since this high dispersion technique can make as many active sites as possible, it can maximize the activity with a small amount of platinum or palladium, which is essential for economical catalyst production. The content of the platinum or palladium is determined according to the content of the aromatic compound of the light oil to be treated. The content of the platinum is preferably 0.1 to 2.0 parts by weight of the platinum precursor in terms of platinum with respect to 100 parts by weight of the carrier. The content is preferably 0.1 to 2.0 parts by weight in terms of palladium precursor in terms of amount of palladium. Here, when the content of platinum or palladium is less than 0.1 parts by weight, the activity is too small to be used. When it exceeds 2.0 parts by weight, the activity is improved, but there is a problem that the economic efficiency is lowered. On the other hand, when platinum or palladium is used alone, the activity is low, and in particular, the resistance to sulfur is lowered, and therefore, it is more preferable to use these two metals together. Here, the weight ratio of palladium to platinum is preferably 0.1 to 10. When the weight ratio is less than 0.1, the platinum content is small and the activity is small. When the weight ratio is more than 10, the palladium content is small and the resistance to sulfur is lowered.

The supported powder catalyst may be prepared into a molded body after preparation, and may be easily introduced into the reactor. Since the porosity is large, the reactant may be passed without resistance. Sudo boehmite of the present invention is known as a binder that can act as a carrier because it is converted to gamma alumina when heated to 400 ℃ or more in the air. However, in the case of preparing the molded body with kaolin and bentonite, which are general inorganic binders, the pores of the carrier are blocked to decrease the pore size and the specific surface area, thereby reducing the dearomatization activity. Therefore, the supported catalyst is added to the sudo boehmite to make a molded body, an acid solution is added to gel it, and then an extrudate is manufactured using an extruder. At this time, the smaller the content of the sudo boehmite is preferred, but in view of strength, the content of the sudoboehmite of the present invention is preferably 5 to 50 parts by weight, and the strength of the molded article is weak when the content of the sudo boehmite is less than 5, If it exceeds 50, the strength of the molded body is improved, but the activity is lowered. On the other hand, the acid solution of the present invention is preferably a concentrated acetic acid, dilute nitric acid or dilute hydrochloric acid aqueous solution, the content of the acid solution is preferably 0.2 to 3.0 parts by weight. The molded body is generally used in a cylindrical or trilobe type (trilobe type).

The molded article prepared as described above is heat treated at 300 to 600 ° C. for 4 to 6 hours to remove organic matter remaining in the molded article, and heat-treat the boehmite to form pores while changing phase to gamma-alumina to serve as a carrier. Binders can be prepared.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following examples.

Examples 1 to 3

A mesoporous molecular sieve was prepared according to the method described in Korean Patent No. 158759. 100 g of 24% hydrogen fluoride solution was taken in each of three polyethylene beakers and 3 g of silica (white carbon) was completely dissolved. _0.930 g, 0.279 g, and 0.140 g of Al (NO ₃ ) _{3 ˙} 9H ₂ O were added to the solution to dissolve uniformly. 100 g of distilled water was taken in three separate beakers, 4 g of cetyltrimetylammonium bromide was dissolved, added to the respective solutions, and stirred at 60 ° C. for 30 minutes. 25 g of 28% ammonia water was added thereto, and the mixture was vigorously stirred at 60 ° C. for 1 hour and then aged while maintaining at 70 ° C. for 16 hours in a drier. Each of them was filtered to recover the precipitate, and then sufficiently washed with distilled water. Each dried powder was calcined at 600 ° C. for 4 hours. The molar ratio of SiO ₂ / Al ₂ O ₃ were respectively 30, 100, 200. 0.027 g of Pt (NH ₃ ) ₄ Cl _2˙ H ₂ O (Alfa, 99.99%) and _0.037 g of Pd (NH ₃ ) ₄ Cl _2˙ H ₂ O (Alfa, 99.999%) After dissolving in 3.74 mL of primary distilled water (Pt 0.5 part by weight, Pd 0.5 part by weight) according to the initial wetness (incipient wetness) method, and dried at 100 ℃. Each dried material was calcined at 450 ° C. for 4 hours to remove organics, thereby preparing a catalyst.

1 g of each catalyst was accurately weighed and placed in a hydrogen reduction apparatus. The hydrogen flow rate was 250 cc / min, the temperature was raised to 400 ° C., hydrogen was passed through for 2 hours, the catalyst was reduced, cooled to room temperature, and the reduced catalyst was placed in an autoclave reactor as soon as possible. Each reactant used for activity measurement was then simulated diesel oil using naphthalene as an aromatic compound and hexadecane as solvent in view of the boiling point of diesel oil. 5 g of naphthalene was dissolved in 95 g of hexadecane, put into each reactor, and the atmospheric pressure was increased to 5 MPa with hydrogen. The concentration change of naphthalene over time was measured at 300 ° C. From these results, the rate constant was determined and the rate constant was obtained. The results are shown in Table 1 below. As shown in Table 1, the molar ratio of SiO ₂ / Al ₂ O ₃ of the mesoporous molecular sieve was the most active at 100, the decomposition rate of hexadecane is less than 1%, so that almost no cracking reaction occurs. It can be seen that.

Catalyst Activity According to Mole Ratio of SiO ₂ / Al ₂ O ₃ Body Active metal Velocity constant k (hr ^-1 ) Hexadecane decomposition rate (%) (after 5 hours) Example 1 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 30) 0.5 parts by weight of Pt 0.5 parts by weight of Pd 7.50 0.18 Example 2 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 0.5 parts by weight of Pt 0.5 parts by weight of Pd 11.56 1.49 Example 3 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 200) 0.5 parts by weight of Pt 0.5 parts by weight of Pd 3.15 0.50

1. Velocity Constant Calculation

Assuming a first order reaction, the equation

= kt

Where C _A0 is the initial naphthalene concentration, C _A is the naphthalene concentration after t hours, and k is the rate constant. The higher the rate constant, the better the reaction.

2. Hexadecane decomposition rate (%) =

Examples 4-6

According to the method of Example 2 to prepare a catalyst comprising the components shown in Table 2, and then to put 200ppm of dibenzothiophene (dibenzothiophene) on the basis of sulfur content to measure the degree of activity degradation by sulfur components Except after the catalytic activity experiment in the same manner as in Example 1, the results are shown in Table 2 below. When platinum and palladium were used together, the activity was much improved than when only platinum was used, and it was found that the addition of platinum and palladium together in terms of sulfur resistance was quite large.

Activity and sulfur resistance by using Pd / Pt Body Active metal Reactant Velocity constant k (hr ^-1 ) Example 4 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 1 part by weight -5 parts by weight of naphthalene-95 parts by weight of hexadecane-200 ppm of dibenzo thiophene based on sulfur 1.035 Example 5 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 1 part by weight -5 parts by weight of naphthalene-95 parts by weight of hexadecane 1.72 Example 2 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 0.5 parts by weight of Pt 0.5 parts by weight of Pd -5 parts by weight of naphthalene-95 parts by weight of hexadecane 11.56 Example 6 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 0.5 parts by weight of Pt 0.5 parts by weight of Pd -5 parts by weight of naphthalene-95 parts by weight of hexadecane-200 ppm of dibenzo thiophene based on sulfur 10.14

Examples 7-10

According to the method of Example 2 was prepared according to the same method as in Example 1 except for preparing a catalyst comprising the components shown in Table 3, the sulfur content based on dibenzothiophene (dibenzothiophene) in the reactor After performing the catalytic activity experiment, the results are shown in Table 3 below. It showed high activity when the weight ratio of palladium / platinum was 0.3 to 3, and showed the highest activity when the weight ratio was 1.

Activity change according to Pd / Pt weight ratio Body Active metal Velocity constant k (hr ^-1 ) Example 4 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 1 part by weight 1.035 Example 7 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 0.75 part by weight Pd 0.25 part by weight 7.22 Example 6 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 0.5 parts by weight of Pt 0.5 parts by weight of Pd 10.14 Example 8 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 0.25 part by weight Pd 0.75 part by weight 7.02 Example 9 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 0.1 part by weight Pd 0.9 part by weight 4.50 Example 10 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 1 part by weight of Pd 3.20

Comparative Examples 1 to 4

Using a zeolite Y, gamma alumina, modern knight and beta zeolite having a molar ratio of SiO ₂ / Al ₂ O ₃ of 60 as a commercially available carrier, a catalyst comprising the components shown in Table 4 was prepared according to the method of Example 2. After the experiment, the results are shown in Table 4 below. As can be seen in Table 4, the rate constant is the highest beta zeolite, but is not suitable as a dearomatic carrier due to the high rate of hexadecane degradation, the catalyst using zeolite Y and the mesoporous molecular sieve has similar activity but zeolite Y In the case of hexadecane, the decomposition rate was large, and it was found that the mesoporous molecular sieve was most suitable as a carrier for the dearomatization catalyst.

Activity Comparison of Mesoporous Molecular Sieves with Commercially Available Carriers Body Active metal Velocity constant k (hr ^-1 ) Hexadecane decomposition rate (%) (after 5 hours) Comparative Example 1 Zeolite Y (SiO ₂ / Al ₂ O ₃ = 60) Pt 1 part by weight 1.77 34.8 Comparative Example 2 Modern Knight (SiO ₂ / Al ₂ O ₃ = 20) Pt 1 part by weight 0.67 4.5 Comparative Example 3 Gamma alumina Pt 1 part by weight 0.68 3.2 Comparative Example 4 Beta zeolite (SiO ₂ / Al ₂ O ₃ = 25) Pt 1 part by weight 3.72 76.5 Example 5 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) Pt 1 part by weight 1.72 1.51

Example 11 and Comparative Example 5

According to the method of Example 2, after preparing a carrier having a ratio of SiO ₂ / Al ₂ O ₃ to 100 to 30g, 0.27g of Pt (NH ₃ ) ₄ Cl _2˙ H ₂ O (Alfa, 99.99%) and Pd ( 0.37 _{g of} NH ₃ ) ₄ Cl _2˙ H ₂ O (Alfa, 99.999%) was dissolved in 37.4 mL of distilled water, and then impregnated with an initial humidity method (0.5 parts by weight of Pt and 0.5 parts by weight of Pd) for 2 hours at 100 ° C. Dried. 12.99 g of sudo boehmite was added thereto, 0.65 g of acetic acid (99%, Jin Chemical) was mixed well, and about 35 g of water was added thereto, and then an extruder was used to prepare a cylindrical catalyst. The prepared molded product was dried at 100 ° C. for 2 hours and then calcined at 550 ° C. for 4 hours to prepare a catalyst. In addition, a catalyst was prepared according to the same method as above except that bentonite was used instead of sudoboehmite. After the activity was measured according to the activity test method of Example 1 by adding 200 ppm of dibenzocyiophene on the basis of sulfur content to each of the prepared catalysts, the results are shown in Table 5 below. In case of using sudoboehmite as a binder, the activity was slightly decreased. However, when bentonite was used, the activity was drastically decreased and the pores were blocked by the binder.

Activity change according to the type of binder carrier Active metal Binder Velocity constant k (hr ^-1 ) Example 11 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 0.5 parts by weight of Pt 0.5 parts by weight of Pd -30 parts by weight of sudoboehmite-70 parts by weight of catalyst carrier and active ingredient 8.92 Comparative Example 5 Mesoporous molecular sieve (SiO ₂ / Al ₂ O ₃ = 100) 0.5 parts by weight of Pt 0.5 parts by weight of Pd -30 parts by weight of bentonite-70 parts by weight of catalyst carrier and active ingredient 2.03

As described above, the present invention relates to a method for preparing a catalyst for dearomatization of light oil, and more particularly, platinum, palladium or a mixture thereof; Mesoporous molecular sieves; And a process for producing a catalyst for dearomatization of light oil which can maintain high dearomatization activity using water boehmite and an acid solution.

The method for preparing the catalyst for dearomatization of light oil according to the present invention increases the yield of the liquid hydrocarbon by suppressing the cracking reaction by using the mesoporous molecular sieve, and has a large surface area pore size and pore volume of the mesoporous molecular sieve. By using the active ingredient to be well dispersed, not only increases the activity, but also prevents deactivation by coke. In addition, the method according to the present invention increases the resistance to the activity and sulfur components of the catalyst by using a combination of platinum and palladium as the active ingredient, the carrier through the heat treatment process during the preparation of the catalyst using the sudo boehmite as a binder By simultaneously playing a role, the activity of the catalyst is improved.

Claims (4)

In the method for producing a catalyst for dearomatization of light oil, 100 parts by weight of a mesoporous molecular sieve prepared using a cationic surfactant micelle template and having a molar ratio of 30 to 300 SiO ₂ / Al ₂ O ₃ and a pore size of 25 to 50 Pa. Supporting 2.0 parts by weight; Shaping by adding 5 to 50 parts by weight of water-boehmite and 0.2 to 3.0 parts by weight of an acid solution to the supported mixture; And Method for producing a catalyst for the dearomatization of light oil, characterized in that it comprises the step of calcining the molded body at 300 to 600 ℃ for 4 to 6 hours. The method of claim 1, wherein the molar ratio of SiO ₂ / Al ₂ O ₃ is 100. The method of claim 1, wherein the weight ratio of palladium to platinum is in the range of 0.1 to 10. The method of claim 1, wherein the acid solution is an aqueous acetic acid solution, an aqueous nitric acid solution, or an aqueous hydrochloric acid solution.