RU2350594C1 - Alumina support, method for making alumina support and method for making dehydrogenation catalyst of c3-c5 paraffin hydrocarbons on this support - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions refers to supports (alumina support), to methods for making supports of catalysts activated in aerated layer and chrome-alumina catalyst for dehydrogenation of C₃-C₅ paraffin hydrocarbons to related olefines being monomers used for manufacturing of chemical rubbers, polymers, blending fuels. There is disclosed alumina support of boehmite morphology, specific surface 80 to 250 m²/g, pore size at least 0.2 cm³/g, microcrystallite size by coherent scattering region 500 to 3000 A. It contains interlayer water in amount corresponding to mole ratio aluminium oxide to water 0.8 to 1.2. There is described method for making support by high-temperature processing of hydrargillite in inert gas and/or ammonia, and/or carbon oxide medium at temperature 100 to 300°C and pressure 0.1 to 150 kgs/cm² and following drying. Besides, there is disclosed method for making dehydrogenation catalyst of C₃-C₅ paraffin hydrocarbons by impregnation of support produced as described above with precursor solutions of chrome oxide, potassium oxide and activating agent representing, at least, one oxide chosen from the group: copper oxide, zinc oxide, manganous oxide, tin oxide, boron oxide, zirconium oxide, there after dried and baked at temperature 600 to 900°C.

EFFECT: production of alumina support, development of production methods and methods for making dehydrogenation catalyst on this support of high mechanical strength, low abrasiveness and high activity and selectivity in dehydrogenation of propane, isobutane and isopentane.

7 cl, 2 tbl, 10 ex

Description

The group of inventions relates to the field of chemical technology and catalytic chemistry, in particular to supports, methods for producing supports for fluidized bed catalysts, and chromium-chromium catalysts for the dehydrogenation of C ₃ -C ₅ paraffinic hydrocarbons to the corresponding olefins, which are monomers for the production of synthetic rubbers , polymers, high-octane components of motor fuels.

Alumochromic catalysts for the dehydrogenation of paraffin hydrocarbons belong to the class of supported catalyst systems and are chromium oxides deposited on the surface of aluminum oxide. To ensure cost-effective values of activity and selectivity, the catalysts are promoted with oxides of alkali and alkaline-earth metals, various modifiers: oxides of silicon, zirconium, tin, lead, etc.

The process of dehydrogenation of paraffins is endothermic, carried out at a temperature above 500 ° C, preferably in a fluidized bed reactor of a microspherical catalyst. Coke deposits formed during the reaction require periodic regeneration of the catalyst at temperatures above 600 ° C. Elevated temperatures, constant residence in a variable redox environment and continuous circulation in the reactor-regenerator system place high demands on the performance of the catalyst: thermal and chemical stability, mechanical strength, abrasion on equipment, which are largely determined by the properties of the alumina carrier and depend from the method of its receipt.

The phase composition of the carrier formed during the synthesis determines the strength of fixing of the active components on its surface, the thermal stability of the finished catalyst. The presence in the composition of the carrier of impurities of aluminum trihydroxides (hydrargillite, bayerite) or low-temperature forms of aluminum oxides (χ-Al ₂ О ₃ , η-Al ₃ O ₃ ) promotes the formation of several crystallographic modifications of aluminum oxides in the catalyst after its thermal activation, which differ in the degree of interaction with precursors of active components, stability in high temperature reaction and regeneration conditions. The abrasion resistance of the catalyst in the fluidized bed, in turn, is determined by the substructural characteristics of the alumina precursors: texture, parameters of pore-forming particles, inherited by them due to the phenomenon of pseudomorphism. The strength of the contacts between the primary particles of aluminum oxide, the shape and size of the aggregates forming the microspherical support, determine both the mechanical strength of the catalyst and its ability to abrasively affect the elements of the dehydrogenation unit: lining of reactors, transfer pipes from the reactor to the regenerator. Therefore, when creating microspherical supports and dehydrogenation catalysts based on them, it is important to form a phase-uniform and mechanically strong support that does not have a significant abrasive effect when operating the catalyst in a fluidized bed.

Possible methods for producing microspherical carriers are spray drying of suspensions of aluminum hydroxides obtained using alumina reprecipitation technology, grinding large granules of aluminum oxides with the selection of particles with a given size distribution (fractional composition), and thermal treatment of hydrargillite.

A known method of producing a microspherical carrier and a catalyst for the dehydrogenation of paraffin hydrocarbons by spray drying suspensions of aluminum salts or aluminum hydroxides in the presence or absence of solutions of the precursors of chromium oxides and alkaline (alkaline-earth) metals. According to the well-known technological scheme (Kolesnikov IM Catalysis and production of catalysts. M .: Tekhnika Publishing House TUMA GROUP, 2004. P.314) a microspherical alumina-chromium paraffin dehydrogenation catalyst is prepared in a drying chamber at 290-300 ° C by spraying a catalyst suspension, including aqueous solutions of CrO ₃ , KOH, K ₂ SiO ₃ , as well as γ-Al ₂ O ₃ and kaolin clay, followed by calcining the obtained microspherical grains at 640-680 ° C in a suspended layer. The composition of the catalyst, wt.%: Al ₂ About ₃ - 72.5-74; SiO ₂ - 9.5-10.5; Cr ₂ O ₃ - 13-14.5; K ₂ O - 2.8-3.3; Fe ₂ O ₃ , CaO, MgO - 1.0. The disadvantages of the method of producing the catalyst are the complexity of the technology, significant energy consumption for water evaporation during spray drying, low mechanical strength due to the use of binders - potassium liquid glass and kaolin clay.

To give greater strength to the catalyst, a method is proposed (US Pat. No. 4,746,643, IPC B01J 23/04; B01J 23/26; publ. 05.24.88 g) for producing an alumina carrier with particle sizes of 20 to 150 microns by spray drying solutions of aluminum salts or aluminum hydroxide followed by two-stage calcination of microspherical granules at 600 ° С and 1100 ° С with the formation of a mixed alumina system consisting of δ-, θ- and α-Al ₂ О ₃ phases with a specific surface area of 40 to 65 m ² / g, volume pores 0.22-0.28 cm ³ / g and an average pore diameter of 20 microns. The dehydrogenation catalyst of the composition, wt.%: Cr ₂ O ₃ - 10-25; K ₂ O - 0.5-3; SiO ₂ - 0.5-3; Al ₂ O ₃ - the rest is prepared by separate impregnation of the support “at initial humidity” with solutions of the precursors of chromium, potassium and silicon oxides, drying in a stream of nitrogen and calcining at 700 ° C. The disadvantages of the method are to obtain a carrier of an inhomogeneous phase composition, consisting of high-temperature forms of aluminum oxides having a low specific surface area, which does not allow to firmly fix chromium oxide on the surface. Further operation of the catalyst in the fluidized bed leads to the entrainment of the active component from its surface.

A known method for producing a combined carrier for a dehydrogenation catalyst (RF Patent No. 2026110, IPC B01J 37/16, B01J 23/26; publ. 09.01.95) by mixing in a bead mill aluminum hydroxide obtained by reprecipitation, with a particle size of 1 up to 25 microns and alumina with a particle size of less than 30 microns. The catalyst is synthesized by repeated impregnation of the resulting combined support with a solution of chromic acid, plasticization in a bead mill, molding the prepared paste into bundles, drying, grinding to particles less than 1 mm in size after each impregnation, and heat treatment in a steam-air medium at 650 ° C. The disadvantages of the proposed method are the multi-stage process, the difficulty of regulating the characteristics of the finished catalyst, a significant amount of waste during grinding and selection of particles of the required size.

The number of stages in the preparation of a microspherical support is significantly reduced when coarse-grained hydrargillite with particles of the required size is used as a precursor. The thermal treatment of hydrargillite particles allows one to obtain X-ray amorphous alumina or crystalline aluminum hydroxide of boehmite morphology, which are used as carriers in the synthesis of paraffin dehydrogenation catalysts.

The formation of boehmite is possible during the solid-phase transformation of hydrargillite during high-temperature treatment in an atmosphere of air or in hydrothermal conditions. In the air atmosphere, the phase transition occurs in the temperature range of 250-350 ° С and is accompanied by the formation of a multiphase system including boehmite and undesirable χ-Al ₂ О ₃ oxide (G. Paglia, CE Buckley, ALRohl, K.Winter, AJStuder, BAHunter, JVHanna. The boemite derived γ-alumina system. 1: Structural evolution with temperature, with the identification and structural determination of a new transition phase, γ'-alumina // Chemistry of Materials. 2004. V.16. P.220). Heat treatment in an aqueous medium at a temperature of 155 ± 5 ° C and above contributes to the formation of monophasic boehmite (Wolf F.F., Kuznetsov S.I. The diagram of equilibrium states of the Al ₂ О ₃ -Na ₂ О-Н ₂ О system // Journal of Applied Chemistry. 1953. T.26. Issue 3. S.298). The process takes a long time - from 40 to 105 hours (Laubengayer AW, Weisz RS A hydrothermal study of equilibria in the system alumina-water // Journal of the American Society. 1943. V.65. No. 2. P.247) .

The closest technical solution to the proposed method for producing a catalyst carrier is a known method of heat treatment of hydrargillite in an autoclave chamber in an aqueous medium at a temperature above 300 ° C and a pressure corresponding to the pressure of saturated water vapor (Usov L.V. On the nature of structural transformations of hydrargillite during heating in autoclave // Journal of Inorganic Chemistry. 1993. T.38. No. 8. P.1279). To accelerate the phase transition, preliminary exposure of hydrargillite in an aqueous solution of potassium bromide and sodium hydroxide is proposed. The disadvantages of this method of producing boehmite are the duration of phase transformations at relatively low temperatures and intensive mechanical destruction of aluminum hydroxide particles, leading to a change in the fractional composition (aluminum hydroxide particle size distribution) in an atmosphere of water vapor at high pressures, which does not allow the use of particles of forming hydroxide in as a catalyst carrier.

Closest to the proposed alumina support for a dehydrogenation catalyst of C ₃ -C ₅ paraffin hydrocarbons is a support that is an X-ray amorphous or partially crystallized aluminum compound of the formula Al ₂ O ₃ · nH ₂ O, where n = 0.3-1.5, with a specific surface 80-250 m ² / g, pore volume 0.1-0.3 cm ³ / g (RF Patent No. 2271248, IPC B01J 21/04, C01F 7/02; publ. 10.03.06). The disadvantages of the proposed carrier are the complexity of the production technology, the formation of a layered structure of an aluminum compound at the stage of rapid high-temperature processing. The conditions of high-temperature treatment of hydroxide determine the shift of hydroxyl packets in crystallites and their splitting into thin plates (Paramzin S.M., Krivoruchko O.P., Zolotovsky B.P., Buyanov R.A., Malakhov V.V., Kryukova G. N., Boldyreva NN Study of the nature of the products of mechanochemical activation of hydrargillite // Bulletin of the Siberian Branch of the Academy of Sciences of the USSR. Ser. Chemical. 1984. No. 17. Issue 6. C. 39. Zolotovsky BP, Buyanov RA, Bukhtiyarova G.A., Taraban E.A., Murin V.I., Grunwald V.R., Demin V.V., Sayfullin R.A. Development of technology and creation of production of spherical alumoxy media, adsorbents and catalysts // Journal of Applied Chemistry. 1997. V.70. Issue 2. P.299). As a result, the surface of aluminum oxide particles becomes heterogeneous, it is a combination of split crystallites with sharp edges and protrusions, which leads to a high abrasive effect of the resulting carrier.

Closest to the proposed method for producing a dehydrogenation catalyst of C ₃ -C ₅ paraffin hydrocarbons is the impregnation of a microspherical support, which is an X-ray amorphous alumina, with solutions of the precursors of chromium, potassium oxides and promoters, followed by drying and calcination at a temperature of 700-800 ° C (RF patent No. 2271860 IPC B01J 23/26, B01J 23/04, B01J 21/04, B01J 21/06, B01J 23/70, C07C 5/333; publ. 03.20.06). The catalyst consists of chromium, potassium, promoter and alumina oxides. The disadvantage of the catalyst is the high abrasive ability, which complicates its use in an industrial environment.

The objective of the proposed group of inventions is the development of a phase-uniform microspherical alumina carrier, a method for producing an alumina carrier and a method for producing a dehydrogenation catalyst of C ₃ -C ₅ paraffin hydrocarbons on this carrier with increased mechanical strength and high activity and selectivity.

The problem is solved by a method of obtaining a carrier of a dehydrogenation catalyst of C ₃ -C ₅ paraffin hydrocarbons by high-temperature treatment of hydrargillite in an atmosphere of inert gas and / or ammonia and / or carbon monoxide, and by a method of producing a catalyst based on it by impregnating the prepared carrier with solutions of chromium oxide precursors, potassium oxide and a promoter, which is at least one of the oxides selected from the group: copper oxide, zinc oxide, manganese oxide, tin oxide, boron oxide, qi rconium, drying and calcining at temperatures from 600 to 900 ° C. Hydrargillite may contain structural water in an amount of from 15 to 50 wt.%.

High-temperature processing of hydrargillite can be carried out at a temperature of from 100 to 300 ° C and a pressure of from 0.1 to 150 kgf / cm ² .

High temperature treatment can be carried out for from 0.1 to 20 hours

The alumina support of the C ₃ -C ₅ paraffin hydrocarbon dehydrogenation catalyst has boehmite morphology, the BET specific surface area is from 80 to 250 m ² / g, the pore volume is not less than 0.2 cm ³ / g, the microcrystallite sizes according to the X-ray diffraction data according to the values of the regions coherent dispersion from 500 to 3000 Å, contains interlayer water in an amount corresponding to a molar ratio of water to alumina from 0.8 to 1.2. The carrier may contain from 0 to 10 wt.% Hydrargillite.

The catalyst may have the following composition, wt.%:

chromium oxide 10-20 potassium oxide 0.1-5 promoter 0.1-5 alumina carrier rest

High-temperature processing is carried out by heating hydrargillite in a closed volume, for example in an autoclave chamber. The pressure in the autoclave is created by an inert gas and / or ammonia and / or carbon monoxide, as well as partially by water vapor released by the dehydroxylation of hydrargillite with the formation of boehmite. The temperature range of high-temperature processing is determined by the range of endothermic effect due to the release of structural water from hydrargillite during its transition to boehmite, observed on the differential thermal analysis curves at temperatures from 100 to 300 ° C (Fig. 1). The process at a temperature of less than 100 ° C is impractical, since there is no phase transition of hydrargillite to boehmite. Heat treatment of hydrargillite at temperatures above 300 ° C is accompanied by intense hydroxide dehydration, a significant increase in pressure in the autoclave chamber, which leads to mechanical destruction of the aggregates and a change in the fractional composition of the powder with the formation of smaller particles.

High-temperature processing of hydrargillite in a confined space in an atmosphere of inert gas and / or ammonia and / or carbon dioxide in the temperature range from 100 to 300 ° C and pressure up to 150 kgf / cm ² ensures the preservation of the fractional composition of the powder and high mechanical strength of aluminum hydroxide aggregates due to reducing the partial pressure of water vapor generated only by isolating hydrargillite from the structure by the dehydroxylation reaction, reducing the structural mobility of crystallites and slowing down the hydroxyl tion-dehydroxylation. In this case, a single-phase coarse-grained boehmite is formed with high mechanical strength, crystallite sizes according to the value of coherent scattering regions from 500 to 3000 Å, the particles of which have the form of smoothed aggregates with a diameter of 50 to 500 μm (Fig. 2).

In contrast to the proposed method, in the prototype, a carrier for a dehydrogenation catalyst for paraffin hydrocarbons is obtained by quickly, within a few seconds, dehydration of hydrargillite, most often in a gas stream, and subsequent cooling, which is accompanied by a violation of the structural ordering of crystallites. The finished carrier is an X-ray amorphous or partially crystallized aluminum compound of the formula Al ₂ O ₃ · nH ₂ O, where n = 0.3-1.5. The formation of microcrystalline pseudoboehmite occurs only during hydration or in the interaction of the carrier with aqueous solutions of the precursors of the catalyst components. In this case, the microspherical carrier retains an inhomogeneous surface with sharp protrusions and edges and exhibits a high abrasive effect.

The catalyst according to the invention is prepared by impregnating a support obtained by high-temperature treatment of hydrargillite in a closed volume in an atmosphere of inert gas and / or ammonia and / or carbon dioxide and representing crystalline aluminum hydroxide boehmite morphology with an interlayer water content corresponding to the molar ratio of water to alumina from 0.8 to 1.2, microcrystallite sizes according to the value of coherent scattering regions from 500 to 3000 Å, specific surface area from 80 to 250 m ² / g, pore volume not less than 0.2 cm ³ / g The impregnation is carried out with aqueous solutions of the precursors of chromium oxide, potassium oxide, the promoter, which is at least one of the oxides selected from the group: copper oxide, zinc oxide, manganese oxide, tin oxide, boron oxide, zirconium oxide, taken from the calculation of the composition finished catalyst, wt.%:

chromium oxide 10-20 potassium oxide 0.1-5 promoter 0.1-5 alumina carrier rest

The carrier is placed in the chamber of the vacuum mixer and degassed. Then, aqueous solutions of the active components and promoters are dosed at a residual pressure of about 30 mm Hg. in an amount corresponding to the moisture capacity of the carrier. The carrier is impregnated with solutions for 0.5-2 hours. After impregnation, the catalyst is dried in vacuum at a residual pressure of 10-30 mm Hg. for 4-6 hours and calcined in air at a temperature of 600-900 ° C for 4-6 hours

Nitrogen, argon, krypton, xenon, or mixtures thereof are used as a source of inert gas.

Ammonia gas is used as a source of ammonia, as well as compounds upon decomposition of which ammonia is released, such as ammonium carbonate, ammonium nitrate, ammonium hydroxide, ammonium fluoride, ammonium chloride, ammonium sulfate, ammonium sulfite, ammonium sulfide, ammonium iodide, etc.

The source of carbon monoxide is gaseous carbon monoxide, gaseous carbon dioxide, as well as compounds, the decomposition of which emits carbon dioxide, such as carbonic acid, ammonium carbonate, sodium carbonate, potassium carbonate, oxalic acid, formic acid, acetic acid, trichloroacetic acid and etc.

As a precursor of chromium oxide, chromic anhydride, potassium chromate, potassium dichromate, chromium hydroxide, chromium nitrate, chromium acetate, chromium oxalate, chromium acetylacetonate, chromium alcoholates, organometallic complex compounds of chromium are used.

As the potassium oxide precursor, potassium carbonate, potassium hydroxide, potassium nitrate, potassium nitrite, potassium sulfate, potassium permanganate, potassium oxalate, potassium acetate or mixtures thereof are used.

Zirconium hydroxide, nitric acid zirconyl, zirconium nitrate, zirconium alkoxy derivatives, zirconium acetylacetonate, zirconium carbonate, zirconium chromate, zirconium dichromate, zirconium chromite, organometallic complexes and other zirconium compounds are used as a precursor of zirconium oxide.

As the precursor of copper oxide, copper sulfate, copper hydroxide, copper nitrite, copper carbonate, copper chromite, copper chromate, copper dichromate, copper acetate, copper acetylacetonate, copper complexes with polyhydric alcohols (e.g. copper glycerate, etc.) or mixtures thereof, organometallic complex compounds of copper, etc.

Zinc hydroxide, zinc nitrate, zinc nitrite, zinc carbonate, zinc chromate, zinc dichromate, zinc chromite, zinc acetate, zinc oxalate, organometallic zinc complexes, etc. are used as a precursor of zinc oxide.

Potassium permanganate, potassium manganate, manganese nitrate, manganese carbonate, manganese acetate, manganese oxalate, manganese chromite, manganese chromate, manganese dichromate, organometallic complex compounds of manganese, etc. are used as a precursor of manganese oxide.

As a precursor of tin oxide, tin hydroxide, tin sulfate, tin fluoride, tin chloride, tin chloride, tin hydrochloric acid, tin acid, tin oxalate, tin acetate, tin acetylacetonate, organometallic complex compounds of tin, and others are used.

As a precursor of boron oxide, boron hydroxide, boron fluoride, boron chloride, boron hydride, metaboric acid, orthoboric acid, sodium metaborate, potassium metaborate, sodium tetraborate, lithium tetraborate, potassium tetraborate, sodium pentaborate, potassium pentaborate, potassium pentaborate, decaborate , calcium triborate, calcium hexaborate, organic borates, orthoboric acid esters, borides, organometallic complex compounds of boron, etc.

The phase composition of the carrier and catalyst is determined by x-ray diffraction. Radiographs are taken using long-wavelength radiation CuKα and a graphite monochromator on a diffracting beam. The range of recording angles in the 2θ scale is from 5 to 95 degrees.

The abrasion resistance is determined by the mass fraction of losses during abrasion of the catalyst in an air stream for 2 hours. The method is based on the destruction of catalyst particles in a fluidized bed and measuring the mass of particles not carried away by a stream of air whose speed is stabilized.

The fractional composition of the carrier is determined by laser readout of the particle size of the powder in suspension. The volume fraction of particles smaller and larger than 70 μm is estimated after an abrasion test in an air stream for 2 hours. The essence of the method for determining the fractional composition is described in ASTM D 031A-930-10-P.

The specific surface area and pore volume are determined by low-temperature nitrogen adsorption. The essence of the method for determining the parameters of a porous system is described in ASTM D 3663-99, “Standard Method for Studying the Surface Area and Pore Volume of Catalysts and Catalyst Carriers.

The particle size is determined by the sieve method.

The external shape of the catalyst particles is determined using an electron scanning microscope.

The content of structural water in hydrargillite is estimated by the magnitude of losses during calcination of aluminum hydroxide at a temperature of 800 ° C for 1 h.

The catalyst is tested in the processes of dehydrogenation of propane, isobutane and isopentane at a dehydrogenation temperature of 560-580 ° C, the volumetric feed rate of 300-400 h ^-1 . Regeneration is carried out with air at a temperature of 650 ° C, keeping the catalyst for 30 minutes. The tests are carried out in a flow-through laboratory type apparatus with a quartz tube reactor in a fluidized bed of a catalyst. The volume of the loaded catalyst is 100 cm ³ . The process is carried out in cycles in the following sequence: dehydrogenation - 15 minutes, inert gas purge - 5 minutes, air regeneration - 30 minutes, inert gas purge - 5 minutes, then the cycles are repeated. After holding the catalyst at a temperature of 580 ° C for 2 hours, two idle cycles are carried out. In the third cycle, during the dehydrogenation reaction, contact gas is taken from 6 to 15 minutes inclusive in an amount of 1 liter. Contact gas is analyzed by gas chromatography. According to the results of chromatographic analysis, the yield of the target olefin on the passed and decomposed paraffin is calculated — the activity and selectivity of the catalyst, respectively.

The specific implementation of the invention is illustrated by the following examples:

Example 1

A hydrargillite powder with a particle size of 50 to 200 μm with a structural water content of 15 wt.% Is placed in an autoclave chamber. High-temperature treatment of hydrargillite is carried out at a temperature of 150 ° C, a pressure of 4.7 kgf / cm ² in a nitrogen atmosphere for 20 hours. After high-temperature processing, the aluminum hydroxide powder is removed from the autoclave chamber and dried at a temperature of 120 ° C to constant weight.

The carrier is boehmite - 90 wt.%, Hydrargillite - 10 wt.%. Boehmite contains interlayer water corresponding to a molar ratio of water to alumina of 1.19, has a specific surface area of 229 m ² / g, a pore volume of 0.27 cm ³ / g, and the values of coherent scattering regions are 531 Å. The catalyst is prepared by impregnating the support with precursor solutions of chromium, potassium and promoter oxides, for which 150 g of support are placed in a vacuum mixer chamber and 60 ml of an aqueous solution containing 19.6 g of chromic anhydride, 11.7 g of potassium dichromate, 0.38 g of copper are dosed acetate monohydrate. The impregnation is carried out for 1 h at a residual pressure of 10 mm Hg The impregnated carrier is dried in vacuo at a residual pressure of 10 mm Hg. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 2

The catalyst carrier and the catalyst are obtained as described in example 1, but use hydrargillite with a structural water content of 16 wt.%, Performing high-temperature treatment at a temperature of 190 ° C, a pressure of 14 kgf / cm ² in an atmosphere of ammonia for 13 hours. The media represents boehmite - 96 wt.%, hydrargillite - 4 wt.%. Boehmite contains interlayer water corresponding to a molar ratio of water to alumina of 1.01, has a specific surface area of 154 m ² / g, a pore volume of 0.24 cm ³ / g, and the values of coherent scattering regions are 790 Å. The carrier is impregnated with an aqueous solution containing 30.5 g of chromic anhydride, 19.8 g of potassium dichromate, 14.3 g of manganese acetate tetrahydrate for 0.5 h at a residual pressure of 30 mm Hg, dried in vacuum at a residual pressure of 10 mmHg. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 3

The catalyst carrier and the catalyst are obtained as described in example 1, but use hydrargillite with a structural water content of 25 wt.%, Carrying out high-temperature processing at a temperature of 220 ° C, a pressure of 23 kgf / cm ² in an atmosphere of carbon dioxide for 10 hours represents boehmite - 99.9 wt.%, hydrargillite - 0.1 wt.%. Boehmite contains interlayer water corresponding to a molar ratio of water to alumina of 0.97, has a specific surface area of 121 m ² / g, a pore volume of 0.29 cm ³ / g, and the values of coherent scattering regions are 1012 Å. The carrier is impregnated with an aqueous solution containing 36.1 g of chromic anhydride, 26.3 g of potassium dichromate, 2.6 g of zirconyl nitrate dihydrate for 2 hours at a residual pressure of 30 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg .art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 4

The catalyst carrier and the catalyst are obtained as described in example 1, but use hydrargillite with a structural water content of 27 wt.%, Performing high-temperature treatment at a temperature of 270 ° C, a pressure of 55 kgf / cm ² in an atmosphere of nitrogen for 8 hours. The media represents It is boehmite, which contains interlayer water corresponding to a molar ratio of water to alumina of 0.91, has a specific surface area of 114 m ² / g, a pore volume of 0.21 cm ² / g, and the values of coherent scattering regions are 1115 Å. The carrier is impregnated with an aqueous solution containing 19.3 g of chromic anhydride, 3.7 g of potassium dichromate, 3 g of tin oxalate for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 5

The catalyst carrier and the catalyst are obtained as described in example 1, but use hydrargillite with a structural water content of 30 wt.%, Performing high-temperature treatment at a temperature of 300 ° C, a pressure of 85 kgf / cm ² in a nitrogen atmosphere for 2 hours. The media represents It is boehmite, which contains interlayer water corresponding to a molar ratio of water to alumina of 0.89, has a specific surface area of 93 m ² / g, a pore volume of 0.27 cm ³ / g, and the values of coherent scattering regions are 2040 Å. The carrier is impregnated with an aqueous solution containing 47.2 g of chromic anhydride, 10.5 g of potassium carbonate, 23.9 g of zinc acetate dihydrate for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg .art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 6

The catalyst carrier and the catalyst are obtained as described in example 1, but the high-temperature treatment of hydrargillite is carried out at a temperature of 300 ° C, a pressure of 150 kgf / cm ² in a nitrogen atmosphere for 0.1 h. The carrier is boehmite, which contains interlayer water, corresponding to a molar ratio of water to alumina of 0.80, has a specific surface area of 81 m ² / g, a pore volume of 0.22 cm ³ / g, the value of coherent scattering regions is 3000 Å. The carrier is impregnated with an aqueous solution containing 23.9 g of chromic anhydride, 5.5 g of potassium carbonate, 2.8 g of tin oxalate for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg. Art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 7

The catalyst carrier and catalyst are obtained as described in example 1, but the high-temperature treatment of hydrargillite is carried out at a temperature of 250 ° C, a pressure of 40 kgf / cm ² in an atmosphere of nitrogen and ammonia for 5 hours. The carrier is boehmite, which contains interlayer water, corresponding to a molar ratio of water to alumina of 0.84, has a specific surface area of 120 m ² / g, a pore volume of 0.24 cm ³ / g, the value of coherent scattering regions is 1240 Å. The carrier is impregnated with an aqueous solution containing 33.5 g of chromic anhydride, 8.2 g of potassium carbonate, 1.4 g of boric acid for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg. Art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 8

The catalyst carrier and catalyst are obtained as described in example 1, but the high-temperature treatment of hydrargillite is carried out at a temperature of 250 ° C, a pressure of 40 kgf / cm ² in an atmosphere of nitrogen and carbon dioxide for 5 hours. The carrier is boehmite, which contains interlayer water corresponding to a molar ratio of water to alumina of 0.9, has a specific surface area of 117 m ² / g, a pore volume of 0.22 cm ³ / g, the value of coherent scattering regions is 1200 Å. The carrier is impregnated with an aqueous solution containing 23.8 g of chromic anhydride, 5.5 g of potassium carbonate, 2.9 g of zirconyl nitrate dihydrate for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg .art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 9

The catalyst carrier and catalyst are obtained as described in example 1, but the high-temperature treatment of hydrargillite is carried out at a temperature of 250 ° C, a pressure of 40 kgf / cm ² in an atmosphere of ammonia and carbon dioxide for 5 hours. The carrier is boehmite, which contains interlayer water corresponding to a molar ratio of water to alumina of 0.87, has a specific surface area of 115 m ² / g, a pore volume of 0.21 cm ³ / g, the value of coherent scattering regions is 1300 Å. The carrier is impregnated with an aqueous solution containing 23.7 g of chromic anhydride, 5.5 g of potassium carbonate, 1.5 g of boric acid for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg. Art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and isopentane are shown in table 2.

Example 10 (comparisons)

The product of the thermochemical activation of hydrargillite, which is an X-ray amorphous alumina in which the molar ratio of water to alumina is 1.05, has a specific surface area of 115 m ² / g and a pore volume of 0.20 cm ³ / g. The carrier is impregnated with an aqueous solution containing 47.2 g of chromic anhydride, 10.5 g of potassium carbonate, 23.9 g of zinc acetate dihydrate for 1 h at a residual pressure of 20 mm Hg, dried in vacuum at a residual pressure of 10 mm Hg .art. and calcined in air at a temperature of 750 ° C for 4 hours

The properties of the obtained media are shown in table 1.

The composition, abrasion resistance and properties of the catalyst in the dehydrogenation reactions of pentane, isobutane and ispentane are shown in table 2.

As can be seen from the above examples, the proposed method allows to obtain a phase-uniform, well-crystallized carrier with sizes of microspherical particles from 50 to 200 μm, having the form of smoothed aggregates, which provides a low abrasive effect of the catalyst based on it. The catalyst prepared using this carrier has high mechanical strength and at the same time has high activity and selectivity in the dehydrogenation reactions of propane, isobutane and isopentane. The proposed method allows to significantly simplify the technology of obtaining a carrier for a paraffin dehydrogenation catalyst by eliminating the laborious stages of reprecipitation of alumina trihydrate, spray drying and thermochemical activation of alumina trihydrate.

Table 1 Media number Media Properties Composition, wt.% H ₂ O / Al ₂ O ₃ mol / mol OCD, Å S _beats , m ² / g V _then cm ³ / g Fractional composition, vol.% Bm Gg less than 70 microns more than 70 microns one 90 10 1.19 531 229 0.27 40 60 2 96 four 1.01 790 154 0.24 46 54 3 99.9 0.1 0.97 1012 121 0.29 33 67 four one hundred - 0.91 1115 114 0.21 52 48 5 one hundred - 0.89 2040 93 0.27 57 43 6 one hundred - 0.80 3000 81 0.22 45 55 7 one hundred - 0.84 1240 120 0.24 twenty 80 8 one hundred - 0.90 1200 117 0.22 fifteen 85 9 one hundred - 0.87 1300 115 0.21 eighteen 82 10 (comparisons) X-ray amorphous Al ₂ О ₃ · nH ₂ О 1.05 115 0.20 89 eleven Gg - hydrargillite; Bm - boehmite; OCD - coherent scattering regions

table 2 Example No. The composition of the catalyst, wt.% Abrasion,% Dehydrogenation Media number Cr ₂ About ₃ K ₂ O Al ₂ O ₃ promoter Propane Isobutane Isopentane compound content VP,% BP,% VP,% BP,% VP,% BP,% one one 12 2.5 85,4 CuO 0.1 6.5 29th 82 49.1 88.2 45.1 86 2 2 17 3.8 76.7 MnO ₂ 2.5 6.2 32,7 84,4 49.2 88.7 42.9 86.1 3 3 twenty 4.9 74,4 ZrO ₂ 0.7 6 33,4 83 49.9 89.4 47.6 86.2 four four 10 1.7 87.1 Sno 1,2 3.6 28.9 86.3 50.1 90 46.8 86.5 5 5 twenty 4.0 71.1 Zno 4.9 1,5 31.5 83.5 48.3 88 47.1 85.8 6 6 12 2.5 84.3 Sno 1,2 3.8 31.8 82,2 fifty 91 46.8 85.9 7 7 16 3,5 80 B ₂ O ₃ 0.5 2 31.9 84.5 51,4 90.2 46.7 86.3 8 8 12 2.5 84.6 ZrO ₂ 0.9 6.4 30.8 82.7 54.6 90.9 47.5 86.1 9 9 12 2.5 85 B ₂ O ₃ 0.5 1.3 30.1 81.9 52,2 90.7 47.1 86 10 (comparisons) 10 12 2.5 85.6 ZrO ₂ 0.9 45.5 28 79 45.5 87.0 40.1 84 VP - the output of the olefin to the missed paraffin; BP - olefin yield on decomposed paraffin.

Claims (7)

1. The alumina carrier of the dehydrogenation catalyst C ₃ -C ₅ paraffin hydrocarbons boehmite morphology, characterized in that the carrier has a BET specific surface area of from 80 to 250 m ² / g, a pore volume of at least 0.2 cm ³ / g, microcrystallite sizes according to X-ray diffraction data, the values of coherent scattering regions are from 500 to 3000 Å, the interlayer water content corresponding to the molar ratio of aluminum oxide to water is from 0.8 to 1.2. 2. The alumina carrier according to claim 1, characterized in that it further comprises from 0 to 10 wt.% Hydrargillite. 3. A method of producing an alumina carrier according to any one of claims 1 and 2 for a dehydrogenation catalyst of C ₃ -C ₅ paraffin hydrocarbons by high-temperature treatment of hydrargillite and subsequent drying, characterized in that the high-temperature treatment of hydrargillite is carried out at a temperature of from 100 to 300 ° C, pressure from 1 to 150 kgf / cm ² in an atmosphere of inert gas and / or ammonia and / or carbon monoxide. 4. The method according to claim 3, characterized in that the hydrargillite contains structural water in an amount of from 15 to 50 wt.% 5. The method according to claim 3, characterized in that the high-temperature treatment of hydrargillite is carried out within 0.1-20 hours 6. A method of producing a dehydrogenation catalyst of C ₃ -C ₅ paraffin hydrocarbons by impregnating the carrier with solutions of the precursors of chromium oxide, potassium oxide and a promoter, which is at least one of the oxides selected from the group: copper oxide, zinc oxide, manganese oxide, tin oxide, boron oxide, zirconium oxide, drying and calcining at a temperature of from 600 to 900 ° C, characterized in that they use the carrier obtained according to claim 3. 7. The method according to claim 6, characterized in that a catalyst is obtained having the following composition, wt.%:
chromium oxide 10-20 potassium oxide 0.1-5 promoter 0.1-5 alumina carrier rest

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