Selective isomerization of xylenes and conversion of ethylbenzene

 

Usage: the extraction of aromatic compounds. Essence: conduct the isomerization of non-equilibrium mixture of ethylbenzene and xylenes on the catalyst in the presence of hydrogen at a temperature of 300-600C, a pressure of 100 kPa to 5 MPa and an average hourly rate of feed of 0.5-100 h-1. When the catalyst contains a zeolite aluminosilicate having a pore diameter of from 5 to 8 E, the component represented by the platinum group metal, and aluminum phosphate or silica as a binder agent, and the finished catalyst has a water absorbing capacity at 4.6 mm RT.art., constituting less than 7 wt.%. The technical result is an increase in the concentration of the desired isomer of xylene. 9 C.p. f-crystals, 2 Il.

The technical field to which the invention relates

The present invention relates to the catalytic conversion of hydrocarbons, and more specifically to a method of isomerization of aromatic compounds.

The LEVEL of TECHNOLOGY

Xylenes - paraxylene, betaxolol and orthoxylene are important intermediate chemical compounds, which find wide and varied application in chemical synthesis. After oxidation of para-xylene is formed terephthal is used in the manufacture of plasticizers, the azo dyes, protective equipment for wood, etc., Orthoxylene is the raw material for the production of phthalic anhydride.

The isomers of xylene, the resulting catalytic reforming process (conversion) or from other sources, as a rule, do not meet the requirements regarding the composition requirements for chemical intermediate compounds, but also include ethylbenzene, which is difficult to separate or to convert. Paraxylene, in particular, is one of the main intermediate products, demand for which is growing rapidly, but its content in the normal flow8-aromatic compounds is not more than 20-25%. Regulation of the isomer ratio needs can be done by combining the selection isomer of xylene, for example, by means of adsorption to extract paraxylene, with isomerization to obtain additional quantities of the desired isomer. Isomerization converts non-equilibrium mixture of xylene isomers, depleted in parts of the desired xylene isomer in the mixture, which is approaching the equilibrium concentrations.

To implement the isomerization of xylene were developed by different catalysts and methods. When choosing the appropriate technology to strive, that is however, this results in more loss of cyclic compounds With8due to side reactions. The approach for achieving balance is a reasonable compromise between the high losses of cyclic compounds With8at high conversion (i.e., at very close approach to equilibrium) and the high cost of production cost because of the high degree of recycling of the unconverted aromatic compounds C8.

Catalysts for the isomerization of aromatic compounds With8usually classified by way of their impact on ethylbenzene associated with the isomers of xylene. Ethylbenzene is not easy isomerized to xylenes, but it is usually transformed into a device for isomerization, since the separation of it from the xylenes by sverhchetkih distillation or adsorption is very expensive. One approach is to conduct the reaction of ethylbenzene with formation of a mixture of xylenes by conversion to naphthenes and reconversion of the naphthenes in the presence of a solid acid catalyst as a function of hydrogenation-dehydrogenation. Alternative widely used approach is to dialkylamino ethylbenzene to education mainly benzene with isomerization of xylenes to obtain approximately the equilibrium mixture. The first approach increases the nversio ethylbenzene, what decreases the number of repeated returns to the extraction device paraxylene, which reduces the related production costs.

In the last nearly twenty years for use in the isomerization of xylene spread crystalline aluminosilicate zeolite-containing catalysts. For example, in US-A-3856872 describes the isomerization of xylene and the conversion of ethyl benzene with a catalyst containing ZSM-5, -12, or -21. In US-A-4626609 describes the conversion of xylene isomers using a catalyst comprising a composite, treated with water vapor at a temperature of from 200 to 500C.

US-A-4899012 describes the use of a catalyst containing lead, the metal of group VIII, the zeolite pentasil and as a bonding agent - inorganic oxide for isomerization of xylenes and ethylbenzene dealkylation. Ongoing research aimed at developing cost-effective isomerization catalysts that best combines the activity, selectivity and stability.

The INVENTION

The main task of the present invention is to develop a new method for isomerization of alkylaromatic hydrocarbons. More conclusively the concentration of the desired xylene isomer.

The present invention is based on the unexpected discovery of the fact that improved conversion of aromatic compounds With8and selectivity in the isomerization of xylene can be achieved when using a zeolite component in the finished catalyst, which has a low absorptivity and includes inert silicon dioxide or aluminum phosphate as a binder agent.

In line with this, the main variant of the embodiment of the invention is directed to a method for the isomerization of alkylaromatic compounds using a catalyst comprising the zeolite aluminosilicate having a pore diameter of from about 5 to 8component, represented by a platinum group metal, and a binder agent, representing inert silicon dioxide or aluminum phosphate, and the catalyst is in the form of the resulting oil-drip method of spherical particles.

The method comprises the isomerization preferably raw materials, including non-equilibrium mixture of xylenes and ethylbenzene in the isomerization conditions to obtain a product having an increased content of paraxylene compared with its content in the feedstock. Suitable conditions arenecessary the feed rate from about 0.5 to 100 h-1. Particularly favorable working conditions - temperature of from about 350 to 500With an average hourly feed rate of the raw material from about 10 to 50-1. Preferred aluminosilicate zeolite is a zeolite of the MFI type. The catalyst has a low absorptivity at a pressure of 4.6 mm RT. senior constituting less than 7 wt.%, and preferably between 3 and 5 wt.%. The platinum group metal preferably includes platinum in low concentration component between 100 and 2000 wt.h. per million parts of catalyst, and optimally between about 200 and 800 mass parts per million parts of catalyst.

These and other objectives and embodiments of the invention will be better understood from the following detailed description of the invention.

BRIEF DESCRIPTION of DRAWINGS

Figure 1 shows the relative activity and selectivity of the catalysts according to the present invention and catalysts known in the art, from the point of view of technological losses of xylenes.

Figure 2 shows the process of the loss of xylenes depending on water number of catalysts.

DETAILED description of the INVENTION

The feedstock to the isomerization of aromatic compounds includes isomi an integer from 1 to 5, a R represents a CH3With2H5With3H7or C4H9in any combination and including all their isomers, for more valuable isomers of alkylaromatic compounds. Suitable alkylaromatic hydrocarbons include, for example, but without limiting this invention, orthoxylene, betaxolol, paraxylene, ethylbenzene, ethyltoluene, trimethylbenzene, propylbenzene, ethyldimethylamine, diethylbenzene, methylpropylketone, ethylpropylamine, triethylbenzene, diisopropylbenzene and mixtures thereof.

Isomerization of mixtures With8aromatic compounds containing ethylbenzene and xylenes, is a particularly preferred application of the invention. Typically, such a mixture has a content of ethylbenzene in the range from about 5 to 50 wt.%, the content of orthoxylene in the range from about 0 to 35 wt.%, the content of metaxalone in the range from about 20 to 95 wt.% and the content of paraxylene in the range from about 0 to 15 wt.% Preferably, the initial8-aromatic compounds include non-equilibrium mixture, i.e. that at least one8-aromatic isomer was present in concentrations significantly different from equally the orthoxylene from fresh raw materials With8aromatic compounds obtained in the production process, such as catalytic reforming and/or extraction destined for the extraction of the aromatics from other hydrocarbons.

In accordance with the present invention can be used alkylaromatic hydrocarbons, which are the respective fractions of different streams of oil refining plants, for example, in the form of individual components or fractions with a certain interval boiling points obtained by the selective fractionation and distillation is subjected to catalytic cracking or reforming of hydrocarbons. You do not want isomerizate aromatic hydrocarbons were concentrated; the method according to the present invention allows the containing isomerization of alkylaromatic compounds streams, such as the product of the catalytic reforming process, with subsequent extraction or without extraction of aromatic compounds, to obtain the desired isomers of xylene, and in particular, paraxylene. Source8-aromatic compounds for the method according to the present invention can contain aromatic opgevoerd consisted essentially of aromatic compounds to reliably obtain the pure products of the threads that go after extraction of the products.

In accordance with the method according to the present invention, the initial mixture of alkylaromatic hydrocarbons, preferably mixed with hydrogen, in contact with the catalyst described below type in the area of the isomerization of alkylaromatic hydrocarbons. The contacting can be performed using the system of the catalyst in a fixed bed system moving bed systems, fluidized bed, or by working in a periodic mode. Because of the risk of loss of expensive catalyst due to abrasive wear, as well as to simplify the operation, it is preferable to use a system with a fixed layer. In this system, enriched with hydrogen gas and the original raw mix is preheated using suitable heating device to the desired reaction temperature and then it is fed to the isomerization zone containing a fixed bed of catalyst. The conversion zone may constitute one or more separate reactors with suitable devices between them, ensuring that the desired temperaturebased or radial flow, and reagents in contact with the catalyst may be in the liquid state, the mixture of liquid and vapor or steam phase.

The original feed mixture of alkylaromatic compounds, preferably a non-equilibrium mixture With8-aromatic compounds, in contact with the catalyst under conditions suitable for the isomerization of alkylaromatic compounds. Such conditions include a temperature of from about 100 to 600With or higher and preferably in the range of from about 350 to 500C.

The pressure is typically from about 100 kPa to 10 MPa, usually not higher than 5 MPa. In the isomerization zone contains a catalyst in a quantity sufficient to provide the average hourly feed rate of the raw material - the source of a mixture of hydrocarbons comprising from about 0.5 to 100 h-1preferably from about 2 to 50 h-1. Good results were obtained at hourly average flow rates of the raw materials that comprise at least about 10 h-1and above. Optimally, to the initial reaction mixture of hydrocarbons carried out in the presence of hydrogen at a molar ratio of hydrogen to hydrocarbon of about 0.5:1 to about 10:1 or higher; may be present and the others who desire the product of isomerization from the stream, resulting from reactor zone isomerization, is not critical to the present invention, and you can use any effective scheme of extraction known in the art.

When combining separation and isomerization related to technological processing of the mixture of ethylbenzene and xylenes, fresh stream8-aromatic compounds combined with the product of isomerization, including8-aromatics and naphthenes, coming from the reaction zone to the isomerization, and served in the area of separation of paraxylene from which extract pure paraxylene. Depleted in paraxylene stream comprising a non-equilibrium mixture With8-aromatic compounds, comprising xylenes and ethylbenzene, from the separation zone is fed to the reaction zone to the isomerization, where C8-aromatic isomers is subjected to isomerization to an estimated equilibrium levels, to obtain a product of isomerization. When such technological scheme uncovered8-aromatic isomers preferably serves for recycling as long as they either will not turn into a paraxylene, or will not be lost as a result of adverse reactions. The selection of orthoxylene, mainly by fractionation, and or, using a combination of both of these threads, preferably before allocating paraxylene.

The isomerization catalyst according to the present invention includes a molecular sieve and a refractory inorganic oxide. The preferred molecular sieve is zeolite aluminosilicates selected from those which have a ratio of Si:Al2average of higher than about 10, preferably above 20, and a pore diameter of from about 5 to 8 angstroms (). Specific examples of suitable zeolites are the following types of zeolites: MFI, MEL, EUO, FER, MFS, MTT, MTW, TON, MOR and FAU. Preferred zeolites group pentasil types MFI, MEL, MTW, and TON, a particularly preferred zeolites of the MFI type, often referred to as ZSM-5.

Relative quantitative content of zeolite in the catalyst may be in the range from about 10 to about 99 wt.% and preferably from about 20 to about 90 wt.%. There is an optimal ratio between the content of zeolite in the catalytic composite, and pressure, temperature and hourly feed rate of the feedstock in the isomerization process, which provides low loss of xylene.

To facilitate the manufacture of the isomerization catalyst used refractory svatuos conditions, used in this way. Suitable binding agents include inorganic oxides, such as one or more of the following: aluminum oxide, magnesium oxide, zirconium dioxide, chromium oxide, titanium oxide, boron oxide and silicon dioxide.

The first preferred binding agent is silicon dioxide. The preferred amorphous silica is a synthetic white amorphous powder of silica (silicon dioxide), which is classified as molded hydrated silicon dioxide. This type of silica is obtained by carrying out chemical reactions in aqueous solution, from which it precipitates in the form of ultrafine spherical particles. Preferably, the area of WET surface of the silicon dioxide was in the range of from about 50 to 800 m2/g, especially from 120 to 160 m2/, Preferably a low content of sulfate salts, preferably less than 0.3 wt.%. Particularly preferably, the amorphous silica binder was non-acidic, i.e., to a pH of 5% aqueous suspension was neutral or alkaline (pH of about 7 or above).

The second preferred binder is an amorphous aluminum phosphate (lumotast). Saalasti technology. The preferred method of obtaining zeolite/aluminophosphate media includes adding zeolite or solo (colloidal solution) of aluminum oxide, or a compound of phosphorus, with the formation of a mixture or Sol of aluminum oxide, zeolite, phosphorus compounds, in the form of particles, using the described oil-drop (oil-drop method, and the calcination of spherical particles.

The preferred oil-drip method of producing catalyst, linked by a phosphate of aluminum, is described in the patent US-A-4629717, which is included in the present description by reference. The method described in the above patent includes gelation of the Hydrosol dioxide aluminum containing compound of phosphorus, using well-known oil-drop method. Usually this method includes obtaining Hydrosol by dissolving aluminum in aqueous hydrochloric acid at temperatures of phlegmy from about 80 to 105C. the Ratio of aluminum to chloride in the ash is from about 0.7:1 to 1.5:1 (by weight). After that, add Sol connection phosphorus. The preferred phosphorus compounds are phosphoric acid, phosphorous acid and ammonium phosphate. The relative amount of phosphorus and al is ntary composition. The Hydrosol of aluminum phosphate type zeolite and the mixture turned into a gel. One way of gelling the mixture includes combining a gelling agent with the mixture, followed by dispersion obtained combined mixture in an oil bath or tower heated to elevated temperatures, so that gelation occurs with the formation of spherical particles. Gelling agents that can be used in this way include hexamethylenetetramine, urea or mixtures thereof. Gelling agents at elevated temperatures produce ammonia, which utverjdaet or turns hydrosaline spherical particles spherical particles of hydrogel. Then these spherical particles are continuously removed from the oil bath and typically subjected to specific treatments, consisting of the extract and drying in oil and in ammoniacal solution, to improve their physical characteristics. Received sustained and gel particles are then washed and dried at relatively low temperatures, comprising from about 100 to 150With, and then subjected to a calcination procedure at a temperature of from about 450 to 700C for from about 1 to 20 hours. The number is recorded in the interval from 10 to 70 wt.%, and preferably from about 20 to 50 wt.%.

The combined mixture is preferably dispersed in an oil bath in the form of drops coming from the nozzle, nozzle or a rotating disk. Alternatively, particles can be molded by spray drying the mixture at a temperature of from about 425 to 760C. In any case, the conditions and equipment should be chosen so as to obtain fine spherical particles; the particles should preferably have an average diameter of less than about 1.0 mm, more preferably from about 0.2 to 0.8 mm and preferably from about 0.3 to 0.8 mm

The degree of crystallinity aluminophosphate a bonding agent can be controlled by varying the content of the phosphate component. Material that is not in the amorphous phase, as a rule, is in the form of gamma alumina; therefore, when the phosphorus content is reduced, the degree of crystallinity increases. Apparent bulk density of spherical particles also varies depending on the content of phosphorus, because the higher content of phosphorus reduces the average bulk density. Surface area is also governed by the content of phosphorus: received Mac is shining up to about 250 m2/g, while the spheroidal particles of aluminum phosphate may have a surface area, comprising up to about 450 m2/, the Atomic ratio Al/P a bonding agent/matrix, typically, ranges from about 1/10 to 100/1, and more typically from about 1/5 to 20/1.

An alternative form of the catalytic composite is extrudate. Extrusion is preferred as the binder agent used silicon dioxide. A well-known method of extrusion includes first mixing the molecular sieve, either before or after addition of the metal components with a bonding agent and a suitable peptization, until a homogeneous pasty mass or thick paste, which have the required moisture content, allowing you to shape extrudates with acceptable level of integrity that can withstand directly following this operation the calcination. The ability to extrusion (extraterrest) is determined by analyzing the moisture content in the doughy mass, and it is preferable for the moisture content in the range from 30 to 50 wt.%. There are many different geometric forms of extrudates, including, but not limited to nizheperechislennyh.

The catalyst according to the present invention may contain a halogen component. Halide component may be a fluorine, chlorine, bromine or iodine, or mixtures thereof, with the preferred is chlorine. Halide component is typically present in a combined state with the carrier of the inorganic oxide. Optional halogen component are preferably well dispersed throughout the catalyst and may comprise from more than 0.2 to about 15 wt.% in the calculation of the elemental composition of the finished catalyst. However, it is preferable that the catalyst did not contain any other additional halogen, moreover, which is associated with other components of the catalyst.

Molded catalyst composite is dried at a temperature of from about 100 to about 320C for from about 2 to about 24 hours or more and usually calicivirus at a temperature of from about 400 to about 650C in air atmosphere for from about 0.1 to about 10 hours up until the present metallic compound will not turn on the merits in oxide form.

Optimally, if the catalytic composite is subjected to treatment with water vapor to bring up is usually required by, processing the composite of zeolite and a binder agent, before the introduction of the platinum group metal. The steam treatment conditions include the concentration of water constituting from about 5 to 100 vol.%, pressure from about 100 kPa to 2 MPa and a temperature of from about 600 to about 1200With; preferably the temperature of the steam treatment is at least about 750With, and not necessarily it can be about 775C or higher. In some cases it can be used in temperatures from about 800 to 850C or higher. Steam processing should be performed for at least one hour, and preferably from 6 to 48 hours.

Alternatively, or in addition to treatment with water vapor composite may be washed one or more of the following substances: solution of ammonium nitrate, mineral acid and/or water. Regarding the first alternative, the catalyst can be washed with a solution containing from about 5 to 30 wt.% ammonium nitrate. When using acid leaching, the preferred mineral acid such as Hcl or an NGO3; add the amount of acid sufficient to obtain a pH of more than 1 to about 6, preferably from about the Asses, preferably from about 1 to 24 hours. Washing can be done at any stage of receiving, it is also possible to apply two or more stages of washing.

Before you add a component that represents a platinum group metal, the composite is preferably subjected to ion-exchange treatment with a salt solution containing at least one forming a hydrogen cation, such as NH4or Quaternary ammonium. Forming a hydrogen cation replaces mainly cations of alkali metals, resulting in the formation after the calcination of the hydrogen form of the zeolite component.

The platinum group metal, including one or more of the following: platinum, palladium, rhodium, ruthenium, osmium and iridium, is an essential component of the present catalyst. The preferred platinum group metals are platinum and palladium, and particularly preferred platinum. Component representing a platinum group metal, can be inside of the finished catalyst composition, in the form of such connection, as the oxide, sulfide, halide, oxysulfide, etc., or as atomic metal or in combination with one or more other components of the catalyst composition. Believe that nailu who is in restored condition. Component representing a platinum group metal, usually ranges from about 100 to about 5000 mass ppm from the finished catalyst composition in the calculation of the elemental composition, particularly suitable is the level of content, comprising from about 100 to about 2000 mass ppm. When using the platinum component of the preferred very low levels, comprising from about 200 to 800 mass parts of platinum per million parts of catalyst, based on the elementary composition; excellent results give the levels that make up less than about 600 mass ppm, and particularly from about 300 to about 500 mass ppm. When using palladium component, the preferred levels, comprising from about 400 to 2000 mass parts of palladium per million parts of catalyst per elementary composition; and particularly preferred levels constituting from about 500 to about 1200 mass parts per million.

Component representing a platinum group metal, can be included in the catalyst composition in any suitable way. One method of preparation of the catalyst involves the use of the fragmented composition sieve/binder agent. Alternatively, the compound of the platinum group metal can be added during preparation of the composition represents the sieve component and a bonding agent.

Another way to implement the appropriate distribution of metal is composed of a metal component with a bonding agent before co-extrusion sieve and a binder agent. Complexes of platinum group metals, which can be used in accordance with the above or with other methods, include hexachloroplatinic acid, chloropalladite acid, chloroplatinic ammonium bromopurine acid, trichloride platinum, tetrachlorethene platinum dichloride dichlorocarbene platinum chloride tetramine platinum, dinitrogen platinum, tetranitromethane (II) sodium, palladium chloride, palladium nitrate, palladium sulfate, hydroxide diamine palladium (II) chloride tetramine palladium (II), etc.

Within the scope of the present invention is that the catalyst may contain other metal components for which it is known that they can modify the action of the component, which is a metal of the platinum group.

After adding the metal component on the Sabbath. C for from about 1 to about 24 hours or more. Then the dried composition calicivirus at a temperature of from about 400 to about 600°C in air for from about 0.1 to 10 hours up until the present metallic compound will not turn on the merits in oxide form.

To provide a uniform and fine dispersion of the optional metal components, whether the composite is better to expose stage essentially anhydrous recovery. Recovery of the catalyst if necessary, you can implement when it is loaded into the reactor for isomerization according to the present invention, to start the process of isomerization. As the reductant at this stage it is preferable to use essentially pure and dry hydrogen (i.e., containing less than 20 parts by volume per million of H2O). The reducing agent contacts the catalyst at conditions including a temperature of from about 200 to about 650With, for from about 0.5 to about 10 hours, effective to recover essentially all of the components, which is a metal of group VIII, the metal state. In some cases, the recovered catalyst composition can be subjected to a prior is lo 0.01 to about 0.5 wt.% sulfur calculated on an elemental composition.

The final catalyst has a water absorbing capacity of the Mac-baine at a pressure of 4.6 mm RT.art., component of between about 2.0 and 7 wt.%, preferably between about 3.0 and about 5.0 wt.%, usually the optimum ratio is between about 3.5 and about 4.5 wt.%. Absorptivity can be measured using the following method.

Stage activation

Record readings (W1) for empty containers, then the catalyst was activated under vacuum for about 16 hours until the next day at a temperature of from 375 to 400With; the vacuum system should be less than 1 millitorr (less than 0.001 mm RT. Art.). The catalyst is cooled to room temperature, and tube Mac-baine, containing the activated catalyst is closed; then record the reading (W2) for the activated catalyst at room temperature. Then around the tank with water build an ice bath to maintain the temperature of the water during the stage of adsorption at level 0C.

Stage adsorption

The pipeline is blown from the water vapor by opening the water tank; a mercury U-shaped pressure gauge should show a pressure of 4.6 Torr (4.6 mm RT.cent.). Open the tube and recording the end time and take a reading (W3) of the catalyst, which was equilibrated with water vapor. Absorptivity calculated as follows.

Absorptivity, wt.%: =[(W2-W3)/(W1-W2)]100

The gradual accumulation of carbon and other deactivating carbonaceous deposits on the catalyst during the isomerization process eventually reduces the activity and selectivity of this process to such a level that it becomes desirable regeneration. When the behavior of the catalyst has deteriorated to a condition requiring regeneration of the catalyst, the introduction of hydrocarbons into a conversion zone containing catalyst, stop, and the conversion zone product stream of a suitable gas. Regeneration can be done to restore the activity and selectivity of the catalyst either in situ or after unloading of the catalyst, outside the production line.

INFORMATION CONFIRMING the POSSIBILITY of carrying out the INVENTION

EXAMPLES

Example I

To illustrate how transaminirovania (parallelomania) according to the present invention have the MFI catalyst associated with aluminum phosphate. The first solution is obtained by adding phosphoric acid to the aqueous solution of hexa is 11 wt.%. The second solution is obtained by adding ammonium exchange of the MFI type zeolite having a ratio Si/Al2at around 39, to sufficient Sol of aluminum oxide obtained by dissolving metallic aluminum in hydrochloric acid, to obtain the content of zeolite in the finished catalyst equal to about 67 wt.%. These two solutions are combined, to obtain a homogeneous mixture NMT, phosphorus, Zola alumina and zeolite. This mixture is dispersed as droplets into an oil bath, which maintain a temperature of about 93C. the Droplets remained in the oil bath until then, until they zahustovali and do not form spherical hydrogel particles having a diameter of about 1.6 mm, These spherical particles are removed from the oil bath, water washed, dried in air and calicivirus at a temperature of about 550C. Then, whether spherical particles subjected to the treatment with water vapor at a temperature of about 660C in an atmosphere of 40% of the water vapor in the air within 12 hours.

Then steamed spherical particles impregnorium (impregnate) the metal with a solution of chloride of tetraamine platinum. At the end of projno in an amount of about 460 mass parts per million (ppm). This isomerization catalyst used to illustrate the method according to the present invention, designated as catalyst A.

Example II

To illustrate how parallelomania according to the present invention have the MFI catalyst associated with silica. Ammonium exchange MFI type zeolite having a ratio Si/Al2at around 38, and Methocel mixed in a machine for the formation of the molding mixture. Powder of hydrated amorphous silica, Ludox AS-40 added in the same proportion, to ensure that the MFI content in the finished catalyst, of about 67 wt.%. Mix and enough deionized water, allowing to obtain an extrudable doughy mass with a water content of about 40 wt.%, carefully mix in the car for the formation of the molding mixture. Then doughy mass ekstragiruyut through the cylindrical head, receiving the cylindrical extrudates with a diameter of about 1.6 mm, Then the catalyst is washed with water, dried in air and calicivirus at a temperature of about 550C, then treated with water vapor at a temperature of about 660C in an atmosphere of 40% of the water vapor in the air 88C for 5 hours, and then washed with deionized water and dried at 510C for about 9 hours. The dried extrudates impregnorium metal by treating them with a solution of hexachloroplatinic acid at temperatures of 60-100C for 6-7 hours. After impregnation, the composite is dried, oxidized and restore, receiving as a result, the catalyst containing platinum in an amount of about 460 mass parts per million (ppm). This isomerization catalyst used to illustrate the method according to the present invention, designated as catalyst A’.

Example III

Associated with oxide catalyst was prepared for use as a control for comparison of the results of isomerization with catalyst A. Get the first solution of aluminium nitrate, to which is added a second solution of NH4OH. The second solution is added slowly, maintaining the pH of the first solution at level 8, until, until gelation of the alumina. The hydrogel of aluminum oxide suspended in water and filtered, the obtained filter cake has a moisture content of about 90 wt.%. Part of the sludge is dried at 150

Extrudable doughy mass produced by combining and mixing about 67 wt.% the MFI zeolite with a hydrogel of aluminum oxide and powdered aluminum oxide. Then doughy mass ekstragiruyut, receiving cylindrical extrudates. The extrudate is immediately subjected to calcination in an air stream at a temperature of approximately 600C.

Then whether the extrudates are subjected to the application, using a solution of chloride of tetraamine platinum. Thereafter, the catalyst is dried, oxidized and restore, receiving as a result, the catalyst containing platinum in an amount of about 400 mass ppm. The reference catalyst is designated as catalyst X.

Example IV

Second control catalyst was prepared for comparison with the catalyst according to the present invention. This catalyst consists essentially of about 11 wt.% the hydrogen form of ZSM-5 and to 0.29 wt.% platinum, and the rest binder is alumina. The MFI zeolite is added to the colloidal solution of aluminum oxide obtained by processing the aluminum metal in hydrochloric acid, in a quantity sufficient to obtain the content of zeolite in the finished catalyst, SOS is Eolica and aluminum oxide, after obtaining a homogeneous mixture. This mixture is dispersed as droplets into an oil bath, which maintain a temperature of about 93C. Drops leave in an oil bath at 150With as long as they are not thick and does not form spherical particles of hydrogel. These spherical particles are removed from the oil bath, washed with 0.5% solution of ammonia in water, dried in air and calicivirus at a temperature of about 650C. Then, whether spherical particles impregnated with a solution of hexachloroplatinic acid, lead as Pb(NO3)2and hydrochloric acid, receiving the content of platinum in the finished catalyst, of about 0.2 wt.% and the lead content is about 0.8 wt.%. Impregnated spherical particles oxidize expose reducing environment N2at a temperature of 565And sarnaut H2S. This catalyst known in the art, is designated as catalyst Y.

Example V

The efficiency of the catalyst according to the present invention and the control catalyst at isomerization evaluated using a pilot plant for processing of ishl 7.3 to 7.4

Paraxylene 0,1

Betaxolol 70,8-71,3

Orthoxylene from 21.3 to 21.8

This initial reaction mixture is subjected to isomerization at a pressure of 1.3 MPa, average hourly feed rate of the raw material 10 h-1and a molar ratio of hydrogen to hydrocarbons of 4. The temperature of the reactor is adjusted to affect the range of the degree of conversion, characterized by the number of ethylbenzene, disappearing in one pass. Ethylbenzene plus a small amount of xylene become mainly benzene and toluene with small amounts of light gases. The results of these tests, in comparison with the losses of valuable xylenes, with 65% conversion of ethylbenzene is presented below:

The catalyst according to the present invention under similar conditions isomerization demonstrates significantly lower loss of xylenes than the catalysts known in the art. The catalyst And’ according to the present invention demonstrates exceptional activity, as evidenced by the low temperature required to achieve a 65% conversion of ethylbenzene, along with low loss of xylenes in comparison with the catalysts known in the art. Relatively is established with representation in Fig.1.

Example VI

Receive a series of catalysts according to the present invention, in order to compare the effect of the concentration of platinum group metal on the efficiency of the isomerization process.

Get whether spherical particles containing zeolite of about 67 wt.%, and process them steam in accordance with the procedure described in example I. Then the spherical particles impregnorium with a solution of chloride of tetramine platinum, dried, oxidized and restore. These spherical particles give the signs, and they contain platinum in amounts specified below, in the mass parts per million (ppm):

Example VII

The effectiveness of the catalysts according to the present invention having a different content of platinum, when isomerization is assessed through experimental setup for technological processing of the initial non-equilibrium mixture With8-aromatic compounds, having the following composition in mol% of:

Ethylbenzene 7,3

Paraxylene 0,1

Betaxolol 71,3

Orthoxylene 21,3

This original blend is subjected to isomerization at a pressure of 1.3 MPa, average hourly feed rate of the raw material 10 h-1and a molar ratio of hydrogen to the reactor is adjusted to affect the range of the degree of conversion, characterized by the number of ethylbenzene, disappearing in one pass. The results of these tests, showing the loss of valuable xylene at 65% conversion of ethylbenzene, is presented below:

Loss of xylene were brought to a minimum content of platinum in the catalyst of about 400 mass ppm or less. The catalytic activity was higher when the content of platinum in the catalyst of about 400 mass ppm and above.

Example VIII

The influence of treatment temperature water vapor on the properties and efficiency of the catalysts studied by obtaining and testing a series of catalysts. Whether spherical particles containing zeolite, comprising about 67 wt.%, receive and process steam in accordance with the method described in example I. the Processing of water vapor are carried out either by a gradual rise of temperature (labeled"ramp"), either directly exposing the catalyst to effect the specified temperature ("flat"). Spherical particles impregnorium, receiving the content of platinum in the catalyst component 350-460 mass parts on millioa 4.6 mm RT. Art., in wt.%, measured by the method described above determine the absorptivity for Mac-baine:

Example IX

The effectiveness of the catalysts obtained in accordance with example VII, when isomerization is assessed through experimental setup for technological processing of the initial non-equilibrium mixture With8-aromatic compounds, as described in example IV. The initial mixture is subjected to isomerization at a pressure of 1.3 MPa, average hourly feed rate of the raw material 10 h-1, a molar ratio of hydrogen to hydrocarbon of 4, at the following temperatures. The results of these tests at 65% conversion of ethylbenzene is presented below:

Reduced absorptivity associated with the activity of the catalyst, the loss of xylene low when carrying out high-temperature treatment with water vapor without the gradual rise in temperature. The results are presented in graphical form in Fig.2.

Example X

The following series of catalysts are obtained from the use of high temperature treatment with water vapor according to the present invention, and their effectiveness examined in accordance with the above po 67 wt.%, and process them steam in accordance with the method described in example I. the steam Treatment is carried out in the following one after the other zones at temperatures of about 725C and 850S, respectively. Catalysts O and Q are the ammonium exchange. Then spherical particles impregnorium, receiving the content of platinum in the catalyst component 350-460 mass ppm, dried, oxidized and restore. The final catalysts are the following indicators of water number 4.6 mm RT. Art., in wt.%, measured by the method described above determine the absorptivity for Mac-baine.

The efficiency of catalysts for isomerization evaluated using the experimental setup for technological processing of the initial non-equilibrium mixture With8-aromatic compounds, as described in example IV. The initial mixture is subjected to isomerization at a pressure of 1.3 MPa, average hourly feed rate of the raw material 10 h-1, a molar ratio of hydrogen to hydrocarbons of 4, and at the following temperatures.

The test results are presented below:

Example XI

Palladium catalysts soglashenie particles impregnorium chloride tetramine palladium. The finished catalysts include palladium content, mass ppm, based on the elemental composition of:

Catalyst L 540

Catalyst M 1130

Example XII

The effectiveness of palladium catalysts according to the present invention isomerization evaluated using the experimental setup for technological processing of the initial non-equilibrium mixture With8-aromatic compounds, having the following composition in mol% of:

Ethylbenzene 7,3

Paraxylene 0,1

Betaxolol 71,4

Orthoxylene 21,2

The initial mixture is subjected to isomerization at a pressure of 1.3 MPa, average hourly feed rate of the raw material 10 h-1and a molar ratio of hydrogen to hydrocarbons of 4. The temperature of the reactor is adjusted to affect the range of the degree of conversion, characterized by the number of ethylbenzene, disappearing in one pass. Ethylbenzene plus a small amount of loss of xylene become mainly benzene and toluene with small amounts of light gases. The results of these tests at 65% conversion of ethylbenzene is presented below:

Claims

1. The way isomerization ishidatami zeolite aluminosilicate, having a pore diameter of from 5 to 8 E, and the finished catalyst has a water absorbing capacity at 4.6 mm RT. senior constituting less than 7 wt.%, component, represented by a platinum group metal, and aluminum phosphate or silica as a binder agent, in the presence of hydrogen in an isomerization zone at a temperature of from 300 to 600°C., a pressure of from 100 kPa to 5 MPa, average hourly feed rate of the raw material constituting from 0.5 to 100 h-1to obtain the product of isomerization with a higher content of at least one xylene isomer than in the original mixture.

2. The method according to p. 1, in which the catalyst contains as a binder agent amorphous aluminum phosphate and has the form of spherical particles, the resulting oil-drop method.

3. The method according to p. 1, in which the catalyst contains as a binder agent inert silicon dioxide.

4. The method according to p. 1, in which the catalyst contains the resulting oil-drop method, the zeolite aluminosilicate and alumina as a binder agent.

5. The method according to any of paragraphs.1-3 or 4, in which the isomer of xylene is a para-xylene.

6. The method according to any of paragraphs.1-4, in which the isomerization conditions include a temperature from about 350 milking, component of from about 2 to 50 h-1.

7. The method according to any of paragraphs.1-4, in which the zeolite aluminosilicate comprises zeolite pentasil selected from the group including MFI, MEL, MTW, and TON.

8. The method according to any of paragraphs.1-4, in which the finished catalyst has a water absorbing capacity at 4.6 mm RT. Art., component of 3-5 wt.% or less.

9. The method according to p. 1, in which component representing the platinum group metal is from about 200 to 800 wt.h. per million of platinum, based on elemental composition.

10. The method according to p. 1, including the removal of ortho-xylene from one or both of the following sources: the product of isomerization and fresh feedstock With8-aromatic compounds.

 

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