KR100305482B1 - Catalyst for Dehydrogenation with Macropores - Google Patents

Abstract

The present invention relates to a catalyst to which an improved carrier which improves the activity, selectivity, and activity stability of a catalyst used for dehydrogenation of a saturated hydrocarbon gas having 5 or less carbon atoms has a pore size of 1, OOo, or more and 10 micron or less. Platinum is used as an active ingredient by applying an alumina carrier having a macropore of at least 0.05cc / g and a maximum of 0.5cc / g and a micropore having a distribution of 10 to 500Å at least 0.10cc / g and at most 0.9cc / g. Pt) is 0.05-2.0% by weight of the final catalyst, tin (Sn) is 0.05-1,0% by weight of the final catalyst, 0.05-3.0% by weight of the alkali group 1 component, chlorine content It is characterized by having a 0.05 to 2.0% by weight, the catalyst formed according to the present invention the greater the performance improvement effect the harsher the reaction conditions for increasing the olefin yield, the less the performance decrease by the repetition of the reaction and regeneration Strong water Physical stability.

Description

Catalyst for Dehydrogenation with Macropores

The present invention relates to a catalyst to which an improved carrier which improves the activity, selectivity, and activity stability of a catalyst used for dehydrogenation of a saturated hydrocarbon gas having 5 or less carbon atoms is applied.

Specifically, the present invention relates to the performance improvement of catalysts for the dehydrogenation of hydrocarbons, in particular for the conversion of saturated hydrocarbons having chains of 5 or less carbon atoms to olefins of the same structure.

It is mainly used for gas phase reactions, and has high conversion, high conversion rate, low hydrogen / hydrocarbon ratio, steam addition, and so on. The present invention relates to a composite metal supported catalyst applying a carrier having macropores and to a preparation thereof.

Conventionally known catalysts have been developed using alumina (Al ₂ O ₃ ) as a carrier and supporting catalysts containing platinum (Pt) and tin (Sn) and catalysts based on chroma (Cr ₂ 0 ₃ ) to form hydrocarbons. It has been used commercially in conversion reactions such as reforming of refined oils and in dehydrogenation reactions (US Pat. No. 3,779,947).

These catalysts are reactions such as dehydrogenation, dehydrogenation reaction, isomerization reaction, aromatization reaction, hydrogenated cracking, etc., which are thermodynamically easy to react at a low temperature of 500 ° C. Has been applied.

Hydrocarbons with 4 or less carbon atoms are very difficult to dehydrogenate, requiring severe reaction conditions and the improvement of catalytic properties that work efficiently under these conditions, altering or adding alkali metal components (US Pat. No. 4,886,928), Catalysts (US Pat. No. 5,012,027) with controlled dispersion and distribution characteristics have been developed.

In order to increase the reaction efficiently, a technique for improving the dehydrogenation performance by changing the structural properties of the alumina carrier effective for the dehydrogenation reaction (US Pat. No. 4,672,146) has been proposed.

Alumina having a gamma-type crystal structure is plastically modified at a high temperature of 900 to 1050 ° C. to apply a theta-type crystal structure alumina having a small surface area but enlarged micropores, and an acidic metal compound and a basic metal using known chelating agents. Techniques for improved catalyst preparation (US Pat. No. 5,482,910) have been proposed in which complex components of a compound are effectively supported by coprecipitation.

The basic direction of the dehydrogenation catalyst for low molecular weight hydrocarbons is a carrier with a specific surface area of more than 150 m2 / g with nitrogen adsorption, and a gamma (γ) crystalline alumina (Al ₂ 0 ₃ ) with a high purity of 99.9% or more. The dehydrogenation performance was improved by supporting effective metal components.

Effective metals include platinum (Pt) as the main metal among the components on the periodic table, and are limited to Group 4B components on the periodic table, especially tin (Sn), lead (Pb), alkalis, especially potassium (K) and sodium. It is well known that a combination of complex metal components such as (Na) and lithium (Li) and components such as chlorine, phosphorus and fluorine is applied.

On the other hand, although the surface area is small, it is possible to reduce the acidity of the carrier itself to minimize the alkali content, or to improve the fine pores of the carrier as measured by nitrogen adsorption method (N2 BET) or to apply the improved carrier to increase the fine pore volume. It has been made.

Alumina with high surface area has been proved experimentally, commercially and usefully that it has a thermal stability and is a considerably superior carrier material due to the ease of carrying active ingredients, ease of control of structural properties, etc. in addition to an active auxiliary role.

However, it is relatively effective in the dehydrogenation and dehydrogenation of hydrocarbons having low temperature or 5 or more carbon atoms, but extremely deficient in the dehydrogenation of low molecular weight hydrocarbons having 5 or less carbon atoms at 550 to 900 ° C, which is 100 to 400 ° C or higher. Accelerating deactivation of the catalyst due to caulking, structural changes in long-term use, and reduction of the active active ingredient area, resulting in deterioration of catalyst performance and shortening of life.

Commercially widely used gamma (γ) crystalline alumina has a strong acidic point and is likely to cause side reactions. The strong acid point causes cracking of the hydrocarbons, thereby lowering the olefin selectivity of the dehydrogenation reaction or increasing the deposition (coking) of the hydrocarbons during the reaction, leading to loss of raw hydrocarbon components and lowering of olefin yield.

A catalyst technique (US Pat. No. 4,677,237), which improves performance by supporting basic alkali metals in alumina to prevent acid control and reduction of surface area, has also been proposed.

However, it is difficult to maintain the intended catalytic performance due to the easy operation of basic operating conditions including reaction conditions requiring high temperature, such as changing the mixing ratio of hydrogen to suppress coking, steam, or hydrogen and steam or carbon monoxide and carbon dioxide. It may lack its own stability

As the reaction temperature increases, the loss of alkali metal used for acid point control may easily occur, which leads to a decrease in dehydrogenation performance.

In the case of a catalyst using a gamma (γ) crystalline alumina as a carrier, there may be a problem of catalyst loss due to changes in inlet gas pressure, catalyst crushing and abrasion with respect to physical strength when the catalyst is moved or replaced.

Reaction conditions, especially temperature close to the plastic transition region of gamma (γ) crystalline alumina, or structural changes such as reduction of the surface area of alumina occur in repeated reaction cycles (repetition of reaction and catalyst regeneration). And ultimately lead to lower catalyst life.

For example, a reduction in surface area can lead to the sintering and condensation of finely dispersed active ingredients, making the catalytic active action itself impossible. This problem can be effectively reduced by using plastically modified theta (θ) alumina.

However, while the maximization and stability of the intrinsic activity of the catalyst itself have been achieved by conventional methods, there have been limitations in reducing the diffusion resistance of reactants and products that may occur under operating conditions in actual commercial application processes.

In particular, the yield of olefin which is dehydrogenated and produced through the reactor increases, so that the reaction of olefin is close to the chemical equilibrium composition, and the reverse reaction is increased, or the conversion performance of the active ingredient or active point is very high, and thus the overall dehydrogenation performance is increased by the catalytic activity. Rather than being controlled, dehydrogenation performance can be limited by the carrier properties that support it relatively.

That is, mass transfer of the reactants or reaction products through the carrier that distributes the active site tends to be restricted, resulting in a general performance degradation. In this case, it is possible to improve the performance by reducing the catalyst particle size used mainly, but it is not easy to actually improve the reaction performance due to various problems such as changes in the reactant flow rate, increased catalyst filling requirements, and pressure loss.

On the other hand, in the case of undesired coking (carbon deposition) generated during the dehydrogenation reaction at high temperature, the active site itself is deposited with a carbon material to decrease the activity, but it prevents the pores of the carrier, which is a delivery path to the active site, to fine. It is also possible to make the active site in the connected micropores unusable for the reaction.

In addition, the carbon deposit is subjected to a regeneration process to remove the carbon precipitate to recover the catalytic activity after a certain period of use of the reaction, when the fine pore structure is applied, it is not easy to penetrate the oxygen The combustion of carbon components is not effectively removed, or changes in the surface structure due to the heat of combustion of carbon deposits, for example, shrinkage of the surface area, and blockage of pores due to sintering of the carrier components, may further reduce the catalyst activity.

The present invention aims to provide a catalyst having improved dehydrogenation reaction performance by applying a carrier having macropores.

1 and 2 are cross-sectional photographs of catalyst particles prepared by Comparative Example 1 and Example 2, respectively.

The catalyst of the present invention has a micropore of at least 0.05cc / g and a maximum of 0.5cc / g with a pore size of at least 1, OOÅ or more and 10 microns or less, and a micropore having a distribution of 10 to 500Å is at least 0.10cc / g or more An alumina carrier having 0.9cc / g or less is applied, and as an active ingredient, platinum (Pt) is 0.05 to 2.0% by weight as elemental weight of the final catalyst, 0.05 to 1.0% by weight of tin (Sn) and 0.05% of alkali group 1 component. It is presumed to have a ˜3.0% by weight and a chlorine content of 0.0 to 2.0% by weight.

Hereinafter, the present invention will be described in detail.

The present invention uses a dehydrogenated composite metal active component and alumina component well known by the prior art, but by applying a carrier having a macroporous structure to prepare a catalyst for the dehydrogenation reaction, the activity is reduced by material transfer, pores by severe caulking It has a function to prevent problems related to dehydrogenation reaction conditions such as clogging and sintering of active ingredients, and it is possible to easily regenerate the catalyst after the reaction and to use a stable catalyst.

Saturated hydrocarbons of 5 or less carbon atoms are the main target reactants of ethane, propane, butane, isobutane and pentane, olefins with a carbon skeleton corresponding to the saturated hydrocarbons used as reactants by dehydrogenation, ie ethylene, propylene, 1-or Converted to 2-butylene, isobutylene, pentene.

Dehydrogenation of the components is an equilibrium reaction in which the maximum olefin yield is limited thermodynamically. Due to the nature of the reaction, endothermic and volume increase reactions, the maximum conversion is limited by chemical equilibrium, so to increase the conversion rate, the reaction temperature should be increased and the reaction pressure should be kept as low as possible.

As the reaction conditions preferred by the catalyst of the present invention, the dehydrogenation reaction temperature is 400 to 900 ° C, specifically 600 to 900 ° C for ethane dehydrogenation, 550 to 700 ° C for propane and 400 to 650 'for butane. For C and isobutane, 450 to 650 ° C, pentane is preferred to 200 to 500 ° C, and the reaction pressure is preferably 0.1 to 10 atm.

In order to continuously or effectively induce the reaction, components added in addition to the saturated hydrocarbons may be a mixture of saturated hydrocarbons and hydrogen or a mixture of the components of the saturated hydrocarbons with hydrogen, or steam or carbon monoxide instead of or together with hydrogen. Is from 0 to 100 mole percent of the amount of hydrocarbon influent to be dehydrogenated.

A liquid space velocity of the saturated hydrocarbon and the catalyst flowing (Liquid Hourly Space Velocity) is 0.1~30hr ^-1, in particular high availability by use of the catalyst composed according to the invention in 0.1~16 hr ^-1. Industrial catalytic reactor types are applicable to all commercially known reactor types, of which fixed bed or fluidized bed reactors are preferred.

The catalyst should have the function of increasing the rate of dehydrogenation to increase the thermodynamic airfoil attainment rate, suppress the formation of structural isomers, and inhibit the thermal decomposition of hydrocarbons that can occur under the reaction conditions, and maintain stable activity under industrial conditions. Should show.

Stability has the effect of increasing the rate of change of activity and selectivity over the use time and the period of continuous use as a catalyst after a specific time, i.e., increasing the economic life of the catalyst.

Factors that reduce the stability of the catalyst include the generation of carbon deposits, i.e., reduction of the contact efficiency with the reactants on the active surface by caulking and the sintering of the active components between the active components generated for various reasons during the reaction or catalyst regeneration. It is mainly due to the decrease of the contact area with the reactants, the change in the conditions of use of the catalyst under industrial conditions, and sometimes caused by the loss into the reactants due to the crushing of the catalyst and the partial loss of the catalyst component.

In order to increase the dehydrogenation performance of the catalyst, selection of appropriate active ingredients and improvement of physical stability of the catalyst itself are also very important. Also, in order to increase the overall activity and to increase the production efficiency of the desired reaction product, that is, the selectivity of pyrolysis and isomerization, etc. The function to reduce side reactions of the polymers should be imposed, and the production and treatment of physicochemical catalysts are required to maintain this performance stably.

According to the conventional published effect, the reaction yield is found to range from 40% to 90% of the theoretical maximum yield (thermodynamic yield) under the conditions under which the comparative test was made.

The dehydrogenation of saturated hydrocarbons of 5 or less carbon atoms is carried out very quickly by the diffusion and reaction of the saturated hydrocarbons, which are reactants, on the catalyst.

It is known that the chemical reaction at the surface of the catalyst is relatively slow as the microscopic reaction characteristic, and the rate of the entire reaction is controlled by the catalyst surface reaction. In this case, the diffusion rate refers to the structure and the structure of active components or components contained microscopically in the catalyst particles when they come into contact with the catalyst in the gas flow of the hydrocarbon reactant, and to the reaction active sites formed by electrochemical effects. After the surface reaction of, all of the unsaturated hydrocarbons generated after the reaction, ie, the rate of migration of olefins out of the catalyst particles, are included.

However, although the olefin yield by the reaction can be easily obtained by varying the catalyst composition and the content to some extent, it is understood that the closer the thermodynamic equilibrium yield, which is the theoretical limit olefin yield, the better the performance by the catalyst is.

In particular, as the reaction temperature is increased to a high temperature or the mixture molar ratio of hydrocarbon to hydrogen is increased to increase the yield of olefins, the mass transfer rate or diffusion rate is relatively slower than the reaction rate of the catalyst surface, that is, the active material of the reaction system in diffusion resistance. Phenomena that can be interpreted as being accelerated are observed.

Increasing the mass transfer or diffusion resistance in the catalyst before and after the reaction, ie, the increase in the effective residence time of the reaction, delays the reaching of the catalytically active component of the reacted saturated hydrocarbons, resulting in good intrinsic activity but overall improvement in the reaction rate. In addition to the dropping phenomenon, it is possible to increase the likelihood of undesirable side reactions such as resorption of the product into the catalyst particles after the reaction, re-reaction of the reaction products, formation of skeletal isomers and conversion to carbon deposits.

In addition, as the reaction proceeds, carbon deposits accumulated in the micropores of the catalyst reduce the function of the transfer and transport passage of reaction-related materials, and thus the main functions of the catalyst, such as catalyst activity, selectivity, and catalyst stability, accelerate the degradation.

In addition to the composition of the catalyst component having a component that exhibits excellent activity, the present invention has a structural structure that facilitates the transfer phenomenon and reduces the diffusion resistance to have a physical structure of the carrier and maximizes such that the improved catalytic activity is sustained. Apply pore.

More specifically, in order to minimize the diffusion resistance, that is, to facilitate mass transfer before and after the reaction, the large pores of the catalyst were imparted to the carrier, and the fine pores and the pore volume were intentionally increased to improve the mass transfer distance between the active ingredient and the catalyst. Pore and surface structure were adjusted to minimize.

The macropores of the present invention have a function as a mass transfer channel that minimizes the mass transfer distance to a set of micropores or minimizes the diffusion resistance.

The expression of the fine pore structure is such that the enlargement of the pores and the reduction of the surface area are close to the active ingredients finely supported on the catalyst, and rather the sintering of the active ingredients can be facilitated, but the change in the structural properties due to the large pores Therefore, it has excellent high temperature resistance and fine dispersibility, leading to an improvement in catalyst performance stability.

The micropores to be classified in the present invention is measured by nitrogen adsorption method (N2 BET) having a size of 500Å or less, mainly 200Å or less, and the macropores which are important in the present invention have a pore size of 1,000Å or more and 10 micron. Below, it can be observed on the cross section or surface at an enlargement ratio of 100 times or more with an electron microscope, and the size distribution of pores can be quantified when the maximum penetration pressure of 15,000 pounds (1b) or more is applied with a mercury (Hg) porosimetry.

The large pores of the present invention may also be expressed as a passage or a void or a hole or cavity. The macropores are not easily measured by nitrogen adsorption because nitrogen gas does not condense in the macropores.

Important considerations in the present invention are the size distribution of total porosity, the total volume, the uniform distribution thereof, the micropore size distribution present in the large pore structure, and the total volume thereof in the unit catalyst weight.

In the present invention, a category that is considered effective for the dehydrogenation of low molecular weight hydrocarbons having 5 or less carbon atoms has a minimum pore volume of at least 0.05 cc / g and a maximum of 0.5 cc / g, and has a pore distribution of 10 to 500 kPa and a minimum of 0.10. It is interconnected structure of more than cc / g and up to 0.9cc / g. At this time, the carrier of the preferred catalyst is alumina having fine porosity, and can be easily prepared to have such a structure.

Preferred catalysts in the present invention have a form, and the presence of such macropores and enlargement of micropores may result in poor catalyst strength. In order to increase the strength, when preparing a carrier having macropores, plastic deformation is performed at 900 to 1200 ° C to impart crystallinity. The crystalline form of the carrier formed in the present invention corresponds to alumina in which theta or alpha and two crystalline forms (alpha and theta) coexist.

The catalyst prepared by the present invention has improved performance which is more differentiated than the catalyst by the conventional method, that is, the harsher the dehydrogenation conditions, the higher the hydrocarbon conversion and selectivity and the performance stability, and the improved resistance to coking and the ease of coking removal. . In the known hydrocarbon conversion reaction, there is no knowledge in the art of improving the performance by utilizing a carrier having such a large pore.

The catalyst structure having high performance in the present invention has a large pore volume of 0.05 to 0.30 cc / g and a fine pore volume of 0.20-0.80, which is basically a double modal having two pore distributions that are apparent in tens of thousands and hundreds of thousands. Has a distribution. The application of such macroporous carriers shows improved activity and ease of regeneration in the dehydrogenation reaction at the time of reaction with the catalyst.

In order to prevent the weakening of the strength caused by the macropores, plastic deformation at 1 to 24 hours at a high temperature of 900 to 1,200 ° C. results in particle breaking strength of 3.Okgf or more. The surface area of the final catalyst has a nitrogen adsorption specific surface area of 150 mm 2 / g or less. Reducing the surface area also requires microdispersion of platinum with major activity, but can lower the total content of effective platinum.

The preferred alkali group 1 component in the catalyst of the invention is potassium (K). It can be prepared from a compound having potassium (K) by various methods, and the final calcining treatment forms a stable oxide. Preferred compounds of potassium (K) are aqueous salts, chlorides and nitrates.

Tin can easily prepare tin-containing alumina by mixing with aluminum-containing components which can be converted to alumina in a high temperature oxidizing atmosphere. The raw material of the tin component is tin chloride salt, which is preferably SnCl ₂ in the solid phase and SnCl ₄ in the liquid phase.

The applied macropore properties of the present invention are determined during the preparation of the carrier material, which can be purchased commercially and applied to the catalyst. Such alumina carriers are obtained through a molding process in various organoaluminum slurries. The preferred carrier in the present invention is organic aluminum having 4 to 14 carbon atoms or less.

The obtained alumina needs heat treatment to have a suitable strength and pore distribution for industrial applications. In the present invention, the gas hourly space velocity (GHSV) in the oxygen or nitrogen gas atmosphere is 300 to 5,000 hr ⁻¹ and 900 to 1,200. hr ^-1 to processes the substrate applicable in the present invention by a high temperature firing process 0.5~20hr ^-1 degree.

This carrier is a crystalline material, and the size distribution of the large pore in the unit carrier weight, the uniform distribution of the total volume, the fine pore size distribution in the large pore structure, and the total volume thereof are important.

In the present invention, the category which is considered to be effective for the dehydrogenation of low molecular weight hydrocarbons having 5 or less carbon atoms has a minimum macropore volume of at least 0.05cc / g and a maximum of 0.5cc / g and a fine pore having a distribution of 10-500Å and at least 0.10 It is interconnected structure of more than cc / g and up to 0.9cc / g.

The crystalline form of the carrier applied in the present invention corresponds to alumina in which theta or alpha and two crystalline forms (alpha and theta) coexist.

In the present invention, the active ingredient refers to a material that can affect the dehydrogenation reaction of saturated hydrocarbons electronically, physically and chemically, and broadly includes a carrier material to finally form metal microparticles, oxides, chlorides, sulfides, hydrides, Halogen salts, oxychlorides, carrier materials or other components in combination.

As a starting material of the platinum component in the present invention is preferably acid (H ₂ chloride are possible such as chloroplatinic acid, ammonium chloride, platinum salts, bromo-platinic acid, platinum chloride hydrate, platinum carbonyl compound or the acid, nitration platinum salt or acid PtCl ₆ ) is preferably supported on the carrier prepared above by a known impregnation method (adsorption method) together with hydrochloric acid.

On the other hand, the impregnation of the platinum-containing solution is applied to the aqueous solution after the final preparation of the carrier material 30% concentration hydrochloric acid of about 1% by weight compared to the carrier used, after 0.5 to 4 hours stirring supporting treatment at room temperature, 0.5- at 80-105 ℃ The supporting solution is stirred for 60 hours.

Thereafter, drying and firing processes are carried out, and dried at 100 to 700 ° C. for 0.5 to 60 hours, and then 500 to 700 ° C. for 0.5 to 20 hours at isothermal gas hourly space velocity (GHSV) at 100 to 5,000 hr. ^{A value of −1} is considered to be advantageous for preventing the condensation at high temperatures of the platinum metal fine particles and for removing excess residual chlorine.

In order to obtain an effective effect in the present invention, the amount of residual chlorine in the final catalyst should be 0.0 to 2.0% by weight, preferably 1.5% by weight or less. The chlorine in the catalyst can be vaporized with an aqueous hydrochloric acid solution after preparation of the final catalyst in addition to the platinum support, to adjust the chlorine content in the final catalyst to 0.0 to 2.0% by weight.

The catalyst of the present invention may also be suitable for the reduction operation to express the performance in the dehydrogenation reaction of the saturated hydrocarbon, which may be used in the actual process, or may be used through a reduction process in advance. The catalyst of this process flows hydrogen having a purity of 99.0% or more to 1.0 to 100 GHSV, and when sufficient is reduced for 0.1 to 48 hours at 400 to 600 ° C, sufficient activity can be expressed.

On the other hand, the catalyst of the present invention may regenerate the deactivated catalyst after the reaction by removing the periodic carbon deposits for long-term use or using steam to improve the activity.

Carbon deposits may be removed by combustion in a nitrogen atmosphere mixed with controlled oxygen, or may gently degass the carbon product in a controlled atmosphere of steam, nitrogen and air. In order to maintain the same activity after the coke component is removed, effective chlorine is supplemented by the vapor phase adsorption method to restore performance.

Embodiments of the present invention are as follows.

Comparative Example 1

Comparative catalysts were prepared using commercial carriers to ascertain the advantages of the catalysts obtained by the present invention. The carrier used lot number 1589 spherical gamma crystalline alumina, which was custom made and supplied by Condea in the Federal Republic of Germany. The preparation of the catalyst was in accordance with US Pat. No. 4,506,032. The size has an average diameter of 1.65 mm and detailed analysis characteristics are shown in Table 1.

1.68 g of tin chloride (SnCl ₂ ) was dissolved in 398 ml of water, and then 8.5 ml of hydrochloric acid was added to completely dissolve the tin chloride. The solution was loaded with 350 g of alumina for 2 hours. Alumina loaded with tin is dried for 2 hours or more under gentle conditions of dry air flow velocity (GHSV; Gas Hourly Space Velocity) at 100hr ^-1 and 150 ° C, and 1000hr dry gas hourly space velocity (GHSV). ^-1 was prepared through a calcination process at 680 ° C. for 3 hours.

A platinum solution was supported by adding a mixture containing 357 ml of a tin-containing carrier, an aqueous platinum chloride solution (platinum concentration 0.00587 g Pt / ml) and 87 ml of water. Thereafter, the mixture was dried at 150 ° C. for 2 hours in dry air, and then calcined at 600 ° C. for 2 hours.

The carrier material containing 350 g of tin and platinum components was immersed in 404 ml of an aqueous solution of 9.05 g of potassium nitrate, dried for 2 hours in 150 ° C. dry air, and calcined at 600 ° C. for 2 hours. This catalyst was referred to as A, and all the components were uniformly loaded through the catalyst particle whole cell and contained 0.58 wt% platinum, 0.3 wt% tin, 1.0 wt% potassium, and 0.78 wt% chlorine.

Example 1

According to the present invention, a catalyst was prepared by applying a macroporous carrier. The process of this example is part of the process illustrated for the invention and the catalyst of the invention is not limited to this process. The alumina used lot number TK 276 spherical gamma alumina which was custom-made in Condea of the Federal Republic of Germany.

The size of the alumina has an average diameter of 1.75 mm and detailed analysis characteristics are shown in Table 1. The alumina was heated in a rotary kiln for 5 hours from 1,000 hours ⁻¹ to 990 ° C. in a dry gas space velocity (GHSV), and then maintained for 3 hours to prepare a theta crystalline carrier.

Example 2

The catalyst was prepared using the carrier obtained in Example 1. 1.28 g of tin chloride (SnCl ₂ ) was dissolved in 398 mL of water, and then 8.5 mL of hydrochloric acid was added to completely dissolve the tin chloride. In this solution, 350 g of the carrier prepared by the method of Example 1 was supported for 4 hours.

Alumina loaded with tin components is dried for 2 hours or more under gentle conditions of 100hr ^-1 , 150 ℃ for dry hourly air velocity (GHSV), and gas hourly space velocity (GHSV) 1,000 It was prepared through a calcination process of 3 hours at 680 ℃ at hr ^-1 .

A platinum component was supported on a tin-containing carrier by adding a mixed solution of 271 ml of aqueous platinum chloride solution (platinum concentration 0.00587 g Pt / ml) and 172 ml of water. Thereafter, the mixture was dried at 150 ° C. for 2 hours in dry air and then calcined at 600 ° C. for 2 hours. 350 g of tin and platinum-containing carrier materials were supported in 404 ml of an aqueous solution in which 9.05 g of potassium nitrate was dissolved, and then dried in 150 ° C. dry air for 2 hours and then calcined at 600 ° C. for 2 hours.

This catalyst was referred to as B and all components were uniformly loaded throughout the catalyst particles and contained 0.45 wt% platinum, 0.22 wt% tin, 1.0 wt% potassium and 0.70 wt% chlorine.

Example 3

In this example, the physical properties of the A prepared by the conventional method and the catalyst B obtained by the present invention were analyzed. Micropore analysis of the catalyst was measured by the nitrogen adsorption method pore volume, average pore size, and surface area in the US Micromeritics ASAP 2000 instrument.

The macropore formation and size of the catalyst were confirmed by cutting the prepared catalyst particles with an electron scanning microscope, which is shown in FIG. The formation of micron-sized macropores is evident.

In addition, the total volume and distribution of macropores were measured on a Qantacron Autoscan Mercury Pore Meter. The macropore amount was measured by the volume of the mercury porosimetry, excluding the micropore amount by the nitrogen adsorption method.

Example 4

In this example, the dehydrogenation performance of A prepared by the conventional method and catalyst B having macropores prepared by the present invention was measured using a laboratory reactor. In order to show improved performance in the use stability of the present invention, catalyst B was subjected to a performance comparison through a carbon deposit regeneration process after the reaction.

The dehydrogenation performance of the catalyst was first charged and reduced by 10cc of the catalyst at 10 hours at 550 ° C. at 200hr ^-1 of gas hourly space velocity (GHSV), followed by reduction of hydrogen and propane. The experiment was conducted.

The liquid space velocity (LHSV) of propane is 5hr ^-1 , the mixing molar ratio of hydrogen and propane is 1: 1, the reaction pressure is 1.5 atm absolute pressure, and the reactor inlet mixed gas is sufficiently preheated to 550 ° C before the reaction zone. After entering the reactor, the temperature of the catalyst packed bed in the reaction zone was maintained at 635 ℃ isothermal.

The gas composition before and after the reaction was analyzed by a gas analyzer connected with the reaction apparatus to determine the propane conversion and selectivity for propylene production in the product after the reaction. The results are shown in Table 2.

After 50 hours of reaction time, the reaction gas was evacuated with nitrogen, and dropped to room temperature. Then, the catalyst having a carbon deposition rate was burned at 550 ° C. for 12 hours to compare the total amount of coke generated in the catalyst with the loss of combustion. In order to compare the ease of combustion removal, the thermogravimetric analyzer was used to raise the temperature from room temperature to 800 ° C. in the air atmosphere, and the change in weight loss due to the combustion of carbon deposits was measured.

Finally, the lower the temperature, the less the change in weight is regarded as the final combustion temperature. The results are shown in Table 3.

As a result of the reaction test, it can be seen that the catalyst of the present invention having macropores shows very stable and excellent performance in the catalytic performance, that is, the conversion and selectivity according to the conversion, selectivity and reaction time. It can be seen that the catalyst B is excellent in terms of generation of carbon deposits and ease of carbon deposits. As a result of repeating the reaction and carbon deposit removal process, it can be seen that the catalyst B is more stable than the conventional catalyst A.

TABLE 1

TABLE 2

TABLE 3

The catalyst constituted by the present invention has a greater performance improvement effect as the reaction conditions are severely increased for increasing the yield of olefin, and the performance decreases due to repeated reaction and regeneration, and has a strong physical stability.

Due to the structural characteristics with large pores, there is little deactivation by caulking, high structural stability allows long-term use, and lower platinum content, which is more expensive than the prior art.

In evaluating the continuous usability of the catalyst, the use of the carrier used in the present invention showed an improved effect in terms of this long life stability. Although the mechanism of interaction between the microscopically and correctly supported catalyst components cannot be confirmed, at least by the use of a carrier constituting the present invention, the stability of continuous use of the catalyst is much improved, and thus it is considered as a category of the claims of the present invention.

Claims (4)

Micropores with pore sizes of more than 1, OOÅ and less than 70 microns have a minimum of 0.05cc / g and a maximum of 0.5cc / g, and a micropore with a distribution of 10 ~ 500 최소 at least 0.10cc / g and at most 0.9cc / g Platinum (Pt) is 0.05 to 2.0% by weight of the final catalyst, tin (Sn) is 0.05 to 1.0% by weight of the final catalyst, and the alkali group 1 component A catalyst for dehydrogenation with macropores, characterized in that it has 0.05 to 3.0 weight% by weight and chlorine content of 0.0 to 2.0 weight%. The catalyst for dehydrogenation reaction according to claim 1, wherein the alkali group I element is potassium (K). 2. The catalyst for dehydrogenation reaction according to claim 1, wherein the crystal state of alumina in the carrier used has a crystal structure of theta (theta) or alpha (α). The catalyst for macrohydrogen dehydrogenation according to claim 1, characterized in that a feather whose inner surface cross section is capable of checking the presence or absence of pores or pores at a magnification of 1,000 or more by pendulum scanning microscope.