KR20210077020A - Dehydrogenation catalyst - Google Patents

Abstract

The present invention relates to a dehydrogenation catalyst in which a platinum group metal, auxiliary metal and a cesium component are supported on an alumina support, wherein the dehydrogenation catalyst has a weight ratio of cesium to the total weight of the catalyst of 0.6 to 0.9 wt%, a weight ratio of the auxiliary metal to the total weight of the catalyst of 0.2 to 0.3 wt%, and an acid site amount of 20 to 150 μmol KOH/g catalyst when the catalyst is titrated with KOH. The dehydrogenation catalyst according to the present invention has a high hydrocarbon conversion rate, selectivity, performance stability and improved caulking resistance and can easily remove coke.

Description

Dehydrogenation catalyst {DEHYDROGENATION CATALYST}

The present invention relates to a catalyst used in the dehydrogenation reaction of hydrocarbons, and more particularly, the long-term operation performance of the catalyst is improved, and the dehydrogenation process can be operated even under the condition of a lower hydrogen consumption, so that the dehydration can improve the yield It relates to the digestion catalyst.

Catalytic dehydrogenation of alkanes to produce alkenes (olefinic hydrocarbons) is an important and well-known hydrocarbon conversion process in the petroleum refining industry. This is because alkenes are generally useful as intermediates in the production of other, more expensive hydrocarbon conversion products. For example, propylene can be used to make polymers and propylene glycol, butylene can be used for high octane motor fuels, and isobutylene can be used to make methyl-t-butyl ether, gasoline additives.

The dehydrogenation reaction of hydrocarbon gas, such as the catalytic dehydrogenation reaction of alkane, proceeds at a high temperature of 550 ° C. As the catalytic reaction proceeds at a high temperature, thermal decomposition and coke formation are accompanied as side reactions thereof, and the degree of these side reactions becomes a key factor determining the selectivity and activity of the catalyst. The coke generation reaction, one of the side reactions, covers the active material on the catalyst with coke to block contact with the reactants, thereby lowering the overall reaction conversion rate. In addition, as the coke is generated, the inlet of the pores present in the catalyst is blocked to promote deactivation of the active material present in the pores.

US Patent Publication No. 2015/0202601 A1 discloses a Group IIIA metal selected from gallium, indium, thallium and combinations thereof; Group VIII noble metal selected from platinum, palladium, rhodium, iridium, ruthenium, osmium and combinations thereof; at least one dopant selected from iron, chromium, vanadium, and combinations thereof; and an optional promoter metal selected from cesium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, and combinations thereof; Disclosed is an alkane dehydrogenation catalyst composition comprising a catalyst support selected from silica, alumina, silica alumina composites, rare earth controlled alumina, and combinations thereof.

Korean Patent Publication No. 2014-0123929 discloses a dehydrogenation catalyst composition for hydrocarbons, comprising: a nano-sized composite containing a group VIII component; a protective film forming agent containing a group IVA component and sulfur; alkaline component; halogen components; and a support having an inner core made of alpha alumina and an outer layer comprising a mixture of gamma alumina and delta alumina. In the prior known dehydrogenation catalyst related patents, the content of the active component of the catalyst and the type of the support is predominant.

In carrying out the dehydrogenation reaction, under high temperature and low hydrogenation reaction conditions, sintering of the metal occurs more easily, so it is very difficult to maintain a high degree of dispersion, and as the reaction proceeds, cracking and side reactions appear and coke (coke) ) is created. Accordingly, there is an urgent need to develop a dehydrogenation catalyst capable of improving catalyst stability by controlling the acidity at which cracking occurs, and having excellent catalyst activity, selectivity, and coke stability.

The present applicant has discovered that by adjusting the acidity of the catalyst to a predetermined range, the process yield can be significantly improved by performing the dehydrogenation process under the conditions of the hydrogen/hydrocarbon ratio downward. In particular, Applicants have discovered that catalysts with acid sites within the scope of the present invention provide lower coke-generation, better long-term stability or greater activity.

It is one object of the present invention to provide catalysts suitable for dehydrogenation reactions which enable increased catalyst long-term performance, low-coke generation and good process yields.

Another object of the present invention is to provide a process for dehydrogenation that achieves increased catalyst long-term performance, low-coke generation and good process yields.

One aspect of the present invention for achieving the above object is,

As a dehydrogenation catalyst in which a platinum group metal, sub-group, and cesium component are supported on an alumina support, the weight ratio of cesium to the total weight of the catalyst is 0.6 to 0.9 wt%, and the weight ratio of the sub-group to the total weight of the catalyst is 0.2 to 0.3 wt% , relates to a dehydrogenation catalyst, characterized in that it has an acid site amount of 20 to 150 μmol KOH/g catalyst when the catalyst is titrated with KOH.

The catalyst is one in which 0.3 to 0.8 wt% of platinum is supported on a support based on the total weight of the catalyst.

The catalyst has a volume density of 0.55 to 0.9 g/cc.

The catalyst support has an average pore size of 5 to 100 nm, a total pore volume of 0.1 to 2.1 cm 3 /g, mesopores having an average pore size of 0.1 to 20 μm, and a total pore volume of 0.1 to 21 cm 3 /g It has a double pore size distribution including all macropores.

Another aspect of the present invention is

In the method for producing a catalyst for the dehydrogenation reaction of hydrocarbons,

providing a support having binary pore properties;

dispersing a cesium precursor in the support to support cesium in the support;

A step of sequentially impregnating, drying and calcining the cesium/support catalyst with tin and platinum to prepare a platinum-tin-cesium/alumina support catalyst,

The weight ratio of cesium to the total weight of the catalyst is 0.6 to 0.9 wt%, the weight ratio of the subsidy to the total weight of the catalyst is 0.2 to 0.3 wt%, and when the catalyst is titrated with KOH, the acid content of 20 to 150 μmol KOH/g catalyst is calculated. It relates to a method for producing a dehydrogenation catalyst, characterized in that it has.

Another aspect of the present invention relates to a process for dehydrogenation of hydrocarbons comprising the step of contacting with a dehydrogenation catalyst of the present invention.

The dehydrogenation catalyst according to the present invention can improve the stability of the catalyst by supporting cesium on platinum-tin/alumina to control the acidity of the carrier and suppress coking of the catalyst. In addition, by increasing the weight ratio of the subsidy to platinum, it is possible to optimize the promotion effect of the subsidy and platinum to improve the catalyst long-term operation performance by increasing the propylene yield and reducing coke.

The dehydrogenation catalyst of the present invention can provide high hydrocarbon conversion and selectivity, stability of performance, improved resistance to coking and ease of coking.

In addition, the catalyst of the present invention adjusts the acid point of the catalyst to a predetermined range to prevent a rapid increase in coke when the hydrogen/hydrocarbon ratio is lowered in the hydrocarbon dehydrogenation reaction, thereby improving the process production. This can improve process economics.

The catalyst of the present invention increases the catalyst volume density to increase the catalyst input mass within the same reactor volume, thereby improving reactor performance and improving process yield.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

It should be noted that, as used herein, the terms 'comprising' or 'comprising' do not exclude the presence of other elements. Likewise, it should also be understood that, in the description of a method including specific steps, the description of 'comprising' a specific step does not exclude the inclusion of other steps.

According to the present invention, cesium is supported on platinum-tin/alumina used in the propane dehydrogenation reaction to control the acidity of the carrier and to suppress coking of the catalyst, thereby improving the stability of the catalyst.

The dehydrogenation catalyst of an embodiment of the present invention is a dehydrogenation catalyst in which a platinum group metal, a sub-group, and a cesium component are supported on an alumina support, and the weight ratio of the sub-group to the total weight of the catalyst is 0.2 to 0.3 wt%, and the catalyst is titrated with KOH It has an acid site weight of 20-150 ml KOH/g catalyst.

The main metal of the catalyst of the present invention is a platinum group metal. The platinum group component may include a noble metal component such as platinum, palladium, ruthenium, rhodium, iridium, osmium, or mixtures thereof. The platinum group metal may be present as a metal element or in a chemical combination with one or more of the other components of the complex as a compound such as an oxide, sulfide, halide, acid halide, etc. in the dehydrogenation catalyst. The platinum component comprises 0.3 to 0.8 wt % of the dehydrogenation catalyst, calculated on an elemental basis.

The catalyst of the present invention comprises 0.3-0.8 wt% of platinum and 0.2-0.3 wt% of tin with respect to the total weight. If the content of the platinum component is less than 0.3 wt%, the reaction activity of the dehydrogenation reaction may be reduced, and if it exceeds 0.8 wt%, the selectivity of propylene may be reduced by the cracking reaction of hydrocarbons by platinum.

As the subsidy, one selected from the group consisting of tin, germanium, gallium, indium, copper, zinc, antimony, bismuth and manganese may be used, and tin is particularly preferred.

The dehydrogenation catalyst according to the present invention is a catalyst having a high weight ratio of the subsid to platinum, and the weight ratio of the subsid to the total weight of the catalyst is preferably 0.2 to 0.3 wt%. If the weight ratio in the subsidy is less than 0.2wt%, the tin prevents the sintering of the platinum particles and improves the dispersion by keeping the particle size of the platinum small. When the weight ratio exceeds 0.3wt%, the accelerating effect on the reaction activity of the catalyst may be reduced due to an excess of auxiliary metal.

The dehydrogenation catalyst according to the present invention is characterized in that cesium is used, and the physical properties of the catalyst can be adjusted by using the content of cesium with respect to the total weight of the catalyst as a variable. Cesium has an excellent effect of blocking acid sites on the support compared to other metals, thereby reducing or substantially blocking unwanted side reactions, and at the same time enhancing the catalytic activity of active metals such as platinum and inhibiting carbon deposition, thereby improving the stability of the catalyst. improve

In the dehydrogenation catalyst according to the present invention, the weight ratio of cesium to the total weight of the catalyst is preferably 0.6 to 0.9 wt%. In addition to further reducing the overall acidity of the catalyst, the presence of cesium can block sites on the metal surface that are active for undesirable side reactions. If the content of the cesium component is less than 0.6 wt%, the acid point of the support cannot be properly controlled, and the acidity of the support increases, thereby increasing the cracking reaction and coke generation. Therefore, the selectivity of the dehydrogenation reaction decreases, and the content of the cesium component increases. If it exceeds 0.9 wt%, cesium may be supported in excess to block the active point of platinum, thereby reducing catalytic activity and reducing the conversion rate of the dehydrogenation reaction.

The catalyst of the present invention may optionally further comprise an alkali metal or alkaline earth metal selected from the group consisting of calcium, potassium, magnesium, lithium, strontium, barium, radium and beryllium.

In the present invention, the acidity amount is a measure of the free acid component on the catalyst support, and is expressed as a value of the amount (μmol) of potassium hydroxide (KOH) neutralized by the acid sites present in 1 g of the catalyst support. .

In the present invention, if the acid point of the catalyst is less than 20 ml KOH/g, if the acid point of the support is too small, the interaction is weak and metal movement occurs a lot and sintering may occur, and if it exceeds 150 ml KOH/g, the excessive acid point is hydrocarbon pyrolysis, producing undesirable methane, and forming carbon deposits on the catalyst, leading to rapid catalyst deactivation.

In the hydrocarbon dehydrogenation reaction, when the hydrogen/hydrocarbon ratio (H ₂ /HC) is lowered, the coke increases rapidly. When the acid content of the catalyst is adjusted within the above range, the coke increases rapidly even when the hydrogen/hydrocarbon ratio is lowered. can be prevented Therefore, when the catalyst of the present invention is used, the dehydrogenation process can be operated under the conditions of the hydrogen/hydrocarbon ratio downward in which the production of the dehydrogenation process is improved, and thus the process yield can be significantly increased.

Preferably, the dehydrogenation catalyst of the present invention has a volume density of 0.55 to 0.9 g/cc, and the volume density of the catalyst determines the amount of catalyst input in the process, and is a factor determining the total active density of the catalyst input in the process to be. If the volume density of the catalyst is less than 0.55 g/cc, the catalytically active metal per unit volume is reduced and the catalytic performance is deteriorated, and when it exceeds 0.9 g/cc, the specific surface area is reduced due to the phase change of the support and the dispersion of the metal is reduced. Catalyst performance may be reduced.

A preferred shape of the catalyst in the present invention is spherical particles having a pellet size of 1.2 to 2.0 mm. The spherical support particles may be continuously prepared by well-known oil-dropping methods, which may be prepared by any technique known in the art. For example, a spherical alumina catalyst support is formed by reacting hydrochloric acid with aluminum metal to form an alumina slurry with Ziegler alumina or alumina hydrosol, and combining the obtained hydrosol or slurry with a suitable gelling agent, thereby maintaining the obtained mixture at a high temperature. It can be manufactured by the method of dripping into an oil bath machine. When the droplets of the mixture form gelled spheres, they are recovered and aged and dried to further improve the physical properties of the support. The aged and gelled particles may then be washed and calcined to obtain a spherical crystalline alumina support.

The catalyst according to the present invention may further include 0.1 to 3.0 wt% of a halogen component based on the total weight of the catalyst. As the halogen component, one selected from the group consisting of chlorine, phosphorus and fluorine is used, and chlorine is particularly preferable. When the halogen content is less than 0.1 wt%, the rate of coke formation on the catalyst is rapidly increased, the coke regeneration property of the catalyst is lowered, and the dispersion of platinum during catalyst regeneration is lowered. When the halogen content exceeds 3.0 wt%, the noble metal caused by halogen The poisoning of the catalyst lowers the activity of the catalyst. That is, the halogen component, particularly chlorine, is combined with the aluminum element of the alumina support to attenuate the properties of the Lewis acid of the alumina itself, thereby facilitating the desorption of the product, and thus has the effect of suppressing the generation of coke. The production of coke is adsorbed on the support itself and the reaction is completed, or the main product/by-product generated at the active site spills-over and accumulates on the support and is finally produced through an additional coking reaction, but it is also a Lewis acid. If the desorption of the product is facilitated by weakening it, the amount accumulated on the support is reduced, thereby reducing coke formation. In addition, the halogen component controls the sintering phenomenon of platinum during the regeneration process of the catalyst.

In the catalyst according to the present invention, the support _{selected from the group consisting of TiO 2} , SiO ₂ , Al ₂ O ₃ , ZrO ₂ , Cr ₂ O ₃ and Nb ₂ O ₅ and mixtures thereof may be used, preferably Alumina is suitable. The θ-crystallinity of alumina is a factor determining the degree of coke generation, and the alumina (Al ₂ O ₃ ) support preferably has a θ-crystal phase of 90% or more. The use of γ-alumina has a large side-reactivity due to the acid site of alumina itself, causes a change in alumina crystallinity during the reaction and a change in structural properties that decreases the specific surface area, and α-alumina is a platinum group active metal due to its low specific surface area. Since the dispersion degree is lowered and the overall active area of platinum is reduced, thereby exhibiting low catalytic activity, it is preferable that the alumina support has a θ-crystal phase of 90% or more.

In the present invention, the support has an average pore size of 5 to 100 nm, mesopores having a total pore volume of 0.1 to 2.1 cm 3 /g, an average pore size of 0.1 to 20 μm, and a total pore volume of 0.1 to 21 cm 3 /g. It has a double pore size distribution including all macropores. Due to this double pore size distribution characteristic, the catalyst of the present invention shows improved activity and ease of regeneration in dehydrogenation during the reaction.

When the pores of the support are less than 5 nm, the mass transfer rate is reduced, and when the pores of the support exceed 20 μm, the strength of the support is lowered. That is, when the pore size is 10 nm or less, Nunus diffusion occurs, and when the pore size is 10 to 1000 nm, transition diffusion occurs. In the dehydrogenation reaction, 10 to 100 nm pores are preferable.

The support has a specific surface area of 75 to 140 m 2 /g. When the specific surface area of the support is less than 75 m 2 /g, the dispersibility of the metal active component is lowered, and when it exceeds 140 m 2 /g, the gamma crystallinity of alumina is maintained high and side reactivity is increased.

The catalyst according to the present invention preferably has a strength of 16 to 75N, and increases the strength to have a rigidity with less crushing even in regeneration or circulation of the catalyst. If the strength of the catalyst is less than 16N, it is easily broken, making it difficult to apply to a continuous reaction system. The dehydrogenation catalyst is accompanied by coke generation and after a certain reaction, it is regenerated by burning coke through an oxidation reaction, and thermal cracking occurs during the process. In addition, under the condition that the catalyst is operated while circulating, friction or impact is applied during transport. In case of using a catalyst that is weak to impact, having high strength gives a great advantage to the operation of the process because the flow of the product is obstructed and the pressure in the reactor is increased to lower the conversion rate of the catalyst.

The dehydrogenation catalyst according to the present invention increases the molar ratio of subsidy to platinum to 0.3-1.6, thereby optimizing the promotion effect of subsidy and platinum to improve catalyst long-term operation performance by increasing propylene yield and reducing coke, and By adjusting the acid point to a predetermined range, it is possible to operate under the hydrogen/hydrocarbon ratio downward condition, which improves the process output by preventing the rapid increase in coke when the hydrogen / hydrocarbon ratio is lowered in the hydrocarbon dehydrogenation reaction, thereby improving process economics. , by increasing the catalyst volume density to increase the catalyst input mass within the same reactor volume, the reactor performance can be improved and the process yield can be improved.

Another aspect of the present invention relates to a method for preparing a catalyst for the dehydrogenation of hydrocarbons. When the dehydrogenation catalyst is prepared by the method of the present invention, a support having binary pore properties is provided.

In the present invention, various supports can be used as the support, and preferably, the support is alumina (Al ₂ O ₃ ) in which 90% or more of the theta-crystal phase can be used. The support having the binary pore property has an average pore size of 5 to 100 nm, a total pore volume of 0.1 to 2.1 cm 3 /g, and an average pore size of 0.1 to 20 μm, and a total pore volume of 0.1 to 21 cm 3 It may be a support including all macropores of /g.

The cesium precursor is dispersed in the support to support cesium in the support. Specifically, a cesium precursor solution is prepared by dissolving a cesium metal precursor in a solvent, and then the precursor solution is impregnated into an alumina carrier.

Subsequently, the cesium/support catalyst is sequentially impregnated with tin and platinum, dried and calcined to prepare a platinum-tin-cesium/alumina catalyst. First, a tin precursor is dissolved in a solvent to prepare a tin precursor solution, and the tin precursor solution is impregnated with cesium-alumina to obtain tin-cesium/alumina. Then, the platinum precursor is dissolved in a solvent to prepare a platinum precursor solution, and the platinum precursor solution is impregnated with tin-cesium-alumina to obtain a platinum-tin-cesium-alumina catalyst.

In the present invention, when the catalyst is titrated with KOH by adjusting the molar ratio of subsidy to platinum and the weight ratio of cesium to the total weight of the catalyst, the sintering temperature can be prepared to have an acid content of 20 to 150 mlKOH/g catalyst.

The solvent may be selected from water or alcohol, respectively, and water is preferable, but is not limited thereto.

As the precursor of the metal used in each step, any commonly used precursor can be used, and in general, metal chloride, nitrate, bromide, oxide, hydroxide ) or one or more selected from acetate precursors may be used.

In the present invention, the step of calcining at 1000 ° C. to 1400 ° C. for 1 hour to 2 hours before loading the active metal or auxiliary metal may be further included. Here, if the calcination temperature is less than 1000 ° C or the heat treatment time is less than 1 hour, the formation of metal-alumina is not sufficient, which is not preferable, and when the heat treatment temperature exceeds 1400 ° C or the heat treatment time exceeds 2 hours, the This is not preferable because there is a risk that the phase may be denatured.

Another aspect of the present invention is a dehydrogenation catalyst in which a platinum group metal, sub-group, alkali metal or alkaline earth metal component is supported on a support, wherein the weight ratio of cesium to the total weight of the catalyst is 0.6 to 0.9 wt %, and the total weight of the catalyst The weight ratio of the subsidy is 0.2 to 0.3 wt %, and when the catalyst is titrated with KOH, it has an acid site amount of 20 to 150 ml KOH / g catalyst. A method for dehydrogenating hydrocarbons comprising the step of contacting with a dehydrogenation catalyst will be. The process of the present invention is applicable to the dehydrogenation of linear hydrocarbons such as ethane, propane, normal butane, pentane, hexane, heptane or octane. For example, the method of the present invention may be used as a process for producing propylene through a dehydrogenation process of propane, but is not necessarily limited to this process.

Dehydrogenation can be carried out at atmospheric pressure or at elevated pressure. The hydrocarbon/hydrogen volume ratio is preferably in the range of 0.1 to 1.5 to optimize the dehydrogenation rate. Proportional to the inactivation ratio, other volumetric ratios may be used.

The method for dehydrogenation of hydrocarbons according to the present invention exhibits an improved effect in terms of long-term stability even when the catalyst performance is reduced and the deactivation is severe even when the reaction conditions are severe. When propane is dehydrogenated at a high temperature using the dehydrogenation catalyst of the present invention, the propane conversion rate, the propylene selectivity in the product, and the propylene yield can be improved.

The catalyst of the present invention is suitable for the hydrogenation and dehydrogenation of any hydrocarbon species. Certain non-limiting examples include hydrogenation reactions such as to convert unsaturated hydrocarbons to less saturated or fully saturated hydrocarbons; and dehydrogenation reactions such as conversion of ethane to ethylene, conversion of propane to propylene, conversion of isobutane to isobutylene, or conversion of ethylbenzene to styrene. The reactant hydrocarbons may be provided in pure form, treated with a diluent such as nitrogen or hydrogen, combined with air or oxygen, or by any method known in the art.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are only for illustrating specific embodiments of the present invention, and the content of the present invention is not limited by the examples.

Preparation Example: Preparation of Dehydrogenation Analytical Catalyst

Purchasing spherical alumina having gamma crystallinity manufactured according to US Patent No. 4,542,113 from Sasol, Germany, using a tubular electric furnace (Koryo Electric Furnace), 1050 at an air flow of 300 ml/min It was thermally deformed at a temperature of ℃ for 2 hours and used as a support for catalyst synthesis. The crystallinity of alumina was measured using X-ray analysis, and it had a theta crystallinity of 90% or more.

A catalyst was prepared using the heat-deformed alumina support by an adsorption support method at room temperature / elevated temperature. 0.0652 g of tin chloride (SnCl ₂ ,>99%, Sigma), 0.8571g of hydrochloric acid (HCl, >35%, JUNSEI), and 0.1071g of nitric acid (HNO ₃ , 70%, Yakuri) were dissolved in 41g of distilled water and then heat deformed 20 g of aged alumina was added and supported. The support solution was dried using a rotary evaporator (HAHNSHIN Scientific Co.), stirred at 25 rpm for 1.5 hours at room temperature, and then dried by rotating at 25 rpm at 80° C. under reduced pressure for 1.5 hours. For complete drying, it was dried in an oven at 105° C. for 15 hours, and heat-treated in a furnace at 700° C. for 3 hours. Thereafter, 20 g of tin-supported alumina was placed in _{39.3228 g of distilled water in which 0.2655 g of chloroplatinic acid (H 2} PtCl ₆ 6H ₂ O, 99.95%, Aldrich), 0.2857 g of hydrochloric acid, and 0.0714 g of nitric acid were dissolved and supported. The supporting solution was dried using a rotary evaporator, stirred at 25 rpm for 1.5 hours at room temperature, and dried by rotating at 25 rpm for 1.5 hours at 80° C. under reduced pressure, dried in an oven at 105° C. for 15 hours, 600 It was heat-treated in a furnace at ℃ for 3 hours. Then, 20 g of tin and platinum-supported alumina _{was placed in 39.7632 g of distilled water in which cesium nitrate (CsNO 3} , >99%, Sigma-Aldrich) 0.2053 g and hydrochloric acid 0.3257 g were dissolved, and supported. The supporting solution was dried using a rotary evaporator, stirred at 25 rpm for 1.5 hours at room temperature, and dried by rotating at 25 rpm for 1.5 hours at 80° C. under reduced pressure, dried in an oven at 105° C. for 15 hours, 600 A dehydrogenation catalyst was prepared by heat treatment in a furnace at ℃ for 3 hours.

Examples 1-4

As shown in Table 1 below, various dehydrogenation catalysts were prepared in which the weight ratio of cesium, the weight ratio of tin, or the amount of acid sites relative to the total weight of the catalyst were included in the scope of the present invention.

Comparative Examples 1-4

As shown in Table 1 below, a dehydrogenation catalyst was prepared in the same manner as in Example 1, except that the weight ratio of cesium to the total weight of the catalyst, the weight ratio of tin, or the amount of acid sites of the catalyst were changed.

Experimental Example 1: Performance test of dehydrogenation catalyst

The dehydrogenation reaction was performed according to the procedure described in the catalyst performance evaluation method while changing the weight ratio of cesium to the total weight of the catalyst or the amount of acid sites of the catalyst, and selectivity, conversion, and yield were measured. The measurement results are shown in Table 1 below.

[Method for evaluating catalyst performance]

The performance of the dehydrogenation catalyst according to the present invention was evaluated in the following manner. 3.2 ml of the catalysts prepared in Examples 1 to 4 and Comparative Examples 1 to 4 were charged into a quartz reactor having a volume of 7 ml, respectively, and then propane A mixed gas of hydrogen and hydrogen was supplied to perform dehydrogenation reactions, respectively. At this time, the ratio of hydrogen and propane was fixed at 0.2:1, and under adiabatic conditions, the reaction temperature was 620°C, the absolute pressure was 0.5 atm, and the dehydrogenation reaction was performed while maintaining the ^{liquid space velocity at 15hr -1.} The gas composition after the reaction was analyzed by gas chromatography connected to the reaction apparatus to measure propane conversion, propylene selectivity and yield in the product.

* In Table 1, wt% refers to the total weight of the catalyst.

As can be seen from the results of Table 1, the catalyst of Comparative Example 1 having a cesium content of 0.5 wt% had a small amount of cesium compared to the catalysts (Examples 1 to 4) of the present invention, and the deactivation rate was higher due to the large number of acid sites in the support. It was fast and a lot of coke was deposited. On the other hand, in the catalyst of Comparative Example 2 having a cesium content of 1.0 wt%, an excess of cesium was supported compared to the catalyst of the present invention (Examples 1 to 4), and thus the activity of the catalyst was reduced.

In addition, when the amount of acid sites is within the range of the present invention, it can be confirmed that the dehydrogenation process can be performed even under the conditions of the hydrogen/hydrocarbon ratio downward, and thus the process yield can be improved. In addition, as a result of performing the oxidative dehydrogenation reaction using the catalyst of the present invention with an adjusted acid site amount, the propane conversion rate, the propylene selectivity in the product, and the propylene yield were high, indicating very excellent catalytic activity. Therefore, it can be seen that the oxidative dehydrogenation catalyst of the present invention exhibits very high catalytic activity by showing high propane conversion rate, propylene selectivity in the product, and propylene yield in propane oxidative dehydrogenation reaction.

Although preferred embodiments of the present invention have been described in detail above, these descriptions are for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains various modifications and changes within the spirit and scope of the present invention. It will be understood that , addition, etc. are possible, and such modifications and changes are to be understood as belonging to the protection scope of the present invention defined by the following claims.

Claims (16)

A dehydrogenation catalyst in which a platinum group metal, sub-group, and cesium component are supported on an alumina support, wherein the weight ratio of cesium to the total weight of the catalyst is 0.6 to 0.9 wt%, and the weight ratio of the sub-group to the total weight of the catalyst is 0.2 to 0.3 wt%. , a dehydrogenation catalyst, characterized in that it has an acid site amount of 20 to 150 μmol KOH/g catalyst when the catalyst is titrated with KOH.
The dehydrogenation catalyst according to claim 1, wherein the dehydrogenation catalyst comprises 0.3 to 0.8 wt% of a platinum group metal based on the total weight of the catalyst.
The dehydrogenation catalyst according to claim 1, wherein the dehydrogenation catalyst has a volume density of 0.55 to 0.9 g/cc.
The dehydrogenation catalyst according to claim 1, wherein the support is selected from the group consisting _{of TiO 2} , SiO ₂ , Al ₂ O ₃ , ZrO ₂ , Cr ₂ O ₃ and Nb ₂ O _{5 and mixtures thereof.} .
The dehydrogenation catalyst according to claim 4, wherein the support is 90% or more of alumina having a θ-crystalline phase.
According to claim 1, wherein the support has an average pore size of 5 to 100 nm, a total pore volume of 0.1 to 2.1 cm 3 /g mesopores, an average pore size of 0.1 to 20 ㎛, and a total pore volume of 0.1 to 21 A dehydrogenation catalyst, characterized in that it is a support including all of the macropores of cm 3 / g.
The dehydrogenation catalyst according to claim 1, wherein the platinum group metal is at least one selected from the group consisting of platinum, palladium, rhodium, ruthenium, iridium and osmium.
The dehydrogenation catalyst according to claim 1, wherein the sub-genus is at least one selected from the group consisting of tin, germanium, gallium, indium, zinc and manganese.
The dehydrogenation catalyst according to claim 1, wherein the sub-genus is tin.
The dehydrogenation catalyst according to claim 1, wherein the support has a specific surface area of 75 to 140 m 2 /g.
In the method for producing a catalyst for the dehydrogenation reaction of hydrocarbons,
providing a support having binary pore properties;
dispersing a cesium precursor in the support to support cesium in the support;
A step of sequentially impregnating, drying and calcining the cesium/support catalyst with tin and platinum to prepare a platinum-tin-cesium/alumina support catalyst,
The weight ratio of cesium to the total weight of the catalyst is 0.6 to 0.9 wt%, the weight ratio of tin to the total weight of the catalyst is 0.2 to 0.3 wt%, and when the catalyst is titrated with KOH, the acid content of 20 to 150 μmol KOH/g catalyst is calculated. A method for producing a dehydrogenation catalyst, characterized in that it has.
12. The method of claim 11, wherein the support having binary pore properties has an average pore size of 5 to 100 nm, a total pore volume of 0.1 to 2.1 cm 3 /g, and mesopores having an average pore size of 0.1 to 20 μm, and total pores A method for producing a dehydrogenation catalyst, characterized in that the support includes all macropores having a volume of 0.1 to 21 cm 3 /g.
12. The method of claim 11, wherein the support is alumina (Al ₂ O ₃ ) in which at least 90% of the theta-crystalline phase is a hydrocarbon dehydrogenation method.
12. The method of claim 11, wherein the method further comprises calcining at 1000°C to 1400°C for 1 hour to 2 hours before loading platinum or tin.
A process for dehydrogenating hydrocarbons comprising the step of contacting a hydrocarbon with the dehydrogenation catalyst according to claim 1 .
16. The method of claim 15, wherein the hydrocarbon comprises one of ethane, propane, propane, normal butane, pentane, hexane, heptane or octane.