Catalyst, method for preparation thereof, and a process of dehydrogenation of c3-c5-paraffin hydrocarbons into olefins
FIELD: petrochemical processes and catalysts.
SUBSTANCE: invention relates to the area of production of olefin hydrocarbons via catalytic dehydrogenation of corresponding C3-C5-paraffin hydrocarbons and can be applied in chemical and petrochemical industries. C3-C5-Paraffin hydrocarbon dehydrogenation catalyst is described containing chromium oxide, alkaline metal oxide, transition metals, and carrier, said carrier being nanostructured oxygen-containing aluminum compound of general formula: Al2O3-x(OH)x*nH2O, wherein x=0-0.28 and n=0.03-1.8, consisting of nanostructured primary particles 2-5 nm in size and characterized by disordered/imperfect layered structure similar to byerlyte structure. Method of preparing this catalyst as well as process of dehydrogenating C3-C5-paraffin hydrocarbons into olefins are also described, the latter being conducted in fluidized bed of described catalyst, which is recycled within the circuit: dehydrogenation reactor - regeneration reactor.
EFFECT: increased mechanical strength at high catalytic activity and stability.
20 cl, 1 dwg, 2 tbl, 10 ex
The invention relates to the field of production of olefinic hydrocarbons by catalytic dehydrogenation of the corresponding paraffin With3-C5hydrocarbons and may find application in the chemical and petrochemical industries.
Physico-chemical characteristics of the reactions of dehydrogenation materially affect technological design process and selection of catalytic systems. Among the main determinants of technological and structural design processes dehydrogenation include:
1. The need to supply a large amount of heat in the reaction zone due to the endothermic nature of the reactions.
2. Providing a high temperature to achieve cost-effective depths dehydrogenation.
3. Small contact time to obtain a high selectivity.
4. The need of burning coke deposits or create catalysts that are resistant to coke.
5. The need for rapid cooling of the reaction products to prevent the passage of the polymerization reaction.
Among the possible technological options dehydrogenation process, to the greatest extent allowing to solve the above problems is a method of dehydrogenation in a fluidized bed microspherical catalyst with catalyst circulation along the contour of the reactor - regenerator. However, the p variant of the process imposes a person requirements to catalyst: he must not only possess high activity, selectivity, thermal stability, but also to have a high resistance to abrasion and at the same time not to possess high abrasive characteristics, contributing to the abrasion equipment.
The literature describes a wide variety of solutions aimed at creating catalytic compositions having the above properties.
Known catalyst containing the oxides of potassium, chromium, silicon, aluminum oxide (SU 1366200, B0J 37/02, 23/26, 1988). The catalyst was prepared by impregnation of alumina previously calcined at 1000-1150°With first solutions of chromium compounds and potassium, followed by drying, and then re-impregnated with a solution of silicon compounds, followed by drying and calcination.
The disadvantage of the catalyst and the method is the low mechanical strength and selectivity.
There is a method of cooking alimohammadi catalyst for dehydrogenation of paraffin hydrocarbons (RF 1736034, B01J 37/02, 23/26, 21/04, 1995), which includes the calcination of aluminum hydroxide in suspension layer by the interaction of temperature 450-800°C for 0.05 to 2.0 with further decrease in temperature to 280-400°, peptization aluminum hydroxide nitric acid with the simultaneous introduction of chromium and potassium compounds, forming by spray drying and calcination, the calcination specified in the conditions subjected to 50-80 wt.% aluminum hydroxide, the rest of 20-50 wt.% aluminum hydroxide calcined at 950-1200°C for 2-10 hours
The catalyst is not sufficiently high activity and stability, low mechanical strength. The method of its production is complex and multi-stage. The molding of the catalyst is carried out at the stage spray drying.
A method of obtaining a catalyst dehydrogenation on the basis of Al, Cr, and Si for the process of dehydrogenation With3-C5-paraffin hydrocarbons (JP 7010350, B01J 23/26, 1995), which includes processing annealing at 500-700°With aluminum oxide particles in the form of microspheres, processing, roasting at a temperature of >1000°within a few hours, processing impregnation of the product of firing a solution containing compounds Cr and compounds For the treatment of drying the obtained product, process, impregnation product drying a solution containing a silicon compound and followed by the post-processing drying and roasting at <700°C.
The disadvantages of the obtained catalyst are also insufficient strength and stability, as well as the complexity and multi-stage process of receipt.
A method of obtaining olefinic hydrocarbons by dehydrogenation in the presence of a catalyst of the following composition, wt.%: Cr2O3- 10,0-30,0; ZnO - 30,0-45,0; Al2About3- OST the aspects [of the Russian Federation 2178398, SS 5/333, 1999]. As the carrier used microspherical beads on the basis of aluminium spinel. Maximum performance in this process, defined by the product of the conversion on selectivity, 52.4% of the original when isobutane flow rate of isobutane 400 h-1and a temperature of 590°C. However, this catalyst has an insufficient mechanical strength.
The known process of dehydrogenation of paraffin hydrocarbons in the presence of a chromium catalyst of the following composition, wt.%: Cr2O3- 10,0-20,0;2O3- 1,0-1,5; Me2O - 0,5-2,5; SiO2- 0,5-2,0; Al2About3- else, where Me is an alkaline metal. As a carrier for the catalyst used microspherical alumina-based gamma-, Delta-, theta-modifications in various ratios. The maximum yield of product (isobutene) was 51.7% at a flow rate of isobutane 400 h-1and temperature 574° [RF 2156233, SS 5/333, 20.09.2000].
Known catalyst for dehydrogenation of paraffin hydrocarbons (RF 2148430, B01J 23/26, 2000), which contains the oxides of chromium 12-23%, the compound of alkaline and/or alkaline-earth metal in the amount of 0.5-3.5% and the connection of non-metal: boron and/or silicon in an amount of 0.1-10%. The catalyst also contains at least one compound of the modifier metal (Ti, Zr, Sn, Fe, Ga, Co, Mn, Mo) in an amount of 0.5 to 1.5%. The catalyst formed by heat treatment of aluminum compounds of the formula Al2About3·nH2Oh, where n=0,3-1,5, x-ray amorphous structure together with other compounds. The catalyst has high activity and selectivity. However, the chemical composition is complex, which creates certain difficulties when playing its properties during preparation.
A known catalyst for the dehydrogenation of paraffin hydrocarbons (RF 2271860, B01J 23/26, 20.03.06)containing chromium oxide compound of alkali metal, Zirconia, promoter and aluminum oxide, the precursor medium - compound of aluminium of the formula Al2About3·nH2Oh, where: n=0,3-1,5, ingenuitea patterns. The catalyst contains as a promoter, at least one compound of a metal selected from the group of zinc, copper, iron in an amount of 0.03-2.0 wt.%. The catalyst preferably formed during the heat treatment of the carrier - aluminum compounds of the formula Al2O3·nH2Oh, where: n=0.3 to 1.5, x-ray amorphous structure, together with compounds of chromium, zirconium, alkali metal promoter from the group of zinc, copper, iron. The catalyst has a high initial activity and selectivity, however, achieving this effect by introducing obivok iron and copper should inevitably lead to an increase in the degree of zakoksovanie catalyst. In addition, it is known that iron oxide isostructural with α-Al2About3and for this reason in the literature was repeatedly described the situation when the presence of large amounts of iron impurities in almograve the catalyst was reduced and its service life due to gradual education in the process of operation inactive solid solution of the active component α- Cr2About3in α-Al2About3.
The closest technical solution is the catalyst contains chromium oxide in quantity 12-23 wt.%, connection alkaline and/or alkaline-earth metal in the amount of 0.5 to 3.5 wt.%, the Zirconia in an amount of 0.1-5 wt.% and at least one oxide promoter from the group of niobium, tantalum, hafnium in an amount of 0.001-2 wt.% aluminum oxide (RF 2200143, SS 5/333, B01J 23/26, 37/02, 10.03.2003). The catalyst formed during the heat treatment of aluminum compounds of the formula Al2O3·nH2O where: n=0.3 to 1.5, x-ray amorphous structure together with the compounds of the above elements. For the preparation of the catalyst is used as a compound of aluminum layered x-ray amorphous structure of the formula Al2O3·nH2O where: n=0.3 to 1.5, preferably with the surface of 50-250 m2/, This compound can be obtained by any known means, for example by rapid dehydration hydrargyri the A.
The disadvantage of this catalyst is that it has no practical application because of the scarcity and high cost of the used compounds of hafnium, niobium, tantalum. In addition, this catalyst does not solve the stability problem.
The objective of the invention is to develop a microspherical catalyst for dehydrogenation of paraffin With3-C5hydrocarbon olefins in a fluidized bed with high mechanical strength, catalytic activity and stability.
The problem is solved by dehydrogenation catalyst With3-C5-paraffin hydrocarbons into olefins, which contains chromium oxide, alkali metal oxide, transition metal oxides, and as a carrier it contains nanostructured oxygen-containing compound of aluminum General formula: Al2O3(OH)x*nH2O, where: x=0-0,28, n=0,03-1,8 consisting of nanostrukturirovannyh primary particles of 2-5 nm in size and characterized by disordered/defective layered structure similar to the structure bayerite.
Oxygen-containing compound of aluminum General formula: Al2O3(OH)x*nH2O get in nonequilibrium conditions by rapid centrifugal termoparnaya processing of aluminum hydroxide in saturated water vapor at elevated temperatures followed riodically cooling the obtained product.
As the source of aluminum hydroxide use hydro-argillite (gibbsite or bayerite.
The catalyst contains, wt%: an 8.0-23.0 chromium oxide - Cr2About3; 0.05 to 5.0 alkali metal oxide - M2About; 0,1-5,0 oxide of the transition metal M O2the rest of the media.
The alkali metal M selected from a number of: Li, Na, K, Rb, Cs.
Transition metal M' selected from the series: Zr and/or CE, and/or U.
The catalyst is an microspheres, with the following distribution of particle size, wt.%: <50 μm - <30; 50-80 μm - 20-30; 80-100 μm - 15-25; 100-120 μm - 15-20; 120-140 µm - 10-15; >140 μm <5.
The active component of the catalyst is microdispersed with a particle size equal to 2-5 nm, oxide α-Cr2About3solid solution of Cr3+in γ-Al2About3composition of Al(21,33-x)CrxAbout32where: x=0,1-2,67, cubic structure.
In the proposed solution as a starting material for the synthesis of the catalyst using oxygen-containing compound of aluminum General formula Al2O3(OH)x*nH2O, where: x=0-0,28, n=0,03-1,8 containing aluminium cations in 4, 5 and 6 coordinated state relative to the oxygen with the surface of 50-250 m2/g, amorphous or poorly crystalsound, or partly crystalline structure, the average particle size of the powder is from 20 to 200 μm. On thermograms this connection the work is characterized by the presence of ecoeffect in the temperature range of 780-850° With appropriate ordering of the crystal structure.
Obtaining oxygen-containing aluminum compounds is carried out using a rapid centrifugal termoparnaya activation of aluminum hydroxide structure hydrargillite (gibbsite) or bayerite at elevated temperature in the insulated chamber under the action of centrifugal forces and subsequent forced cooling (RF 2237019, C01F 7/02, 27.09.2004). According to scanning electron microscopy oxygen-containing compound of aluminum General formula: Al2O3(HE)x*nH2O, where: x=0-0,28, n=0,03-1,8 obtained by the method of centrifugal termoparnaya activation, then the product - CTA, has a particle shape close to spherical.
Centrifugal thermal activation hydrargillite (gibbsite) or bayerite carried out in the installation, which is a chamber inside which rotates a solid carrier is shaped in a special way the plate. The rotation speed can be changed and determines the contact time. Under the plate there are heating elements. The temperature of the coolant regulate three thermocouples. Technical hydrate of alumina (hydro-argillite) or bayerite of the bin is served on a heated plate, abruptly heated under the action of centrifugal force moves along the surface of the heat transfer medium to the chamber walls, nubiennes the cooling jacket. When you blow the heated particles of the product activation on cold walls of the chamber is rapid cooling (quenching). The camera is equipped with holes for steam to escape and receiving bin for powder.
Media-based product CTA is an oxygen-containing compound of aluminum General formula: Al2About3(OH)x*nH2O, where: x=0-0,28, n=0,03-1,8, which includes amorphous phase formed of nanostructured primary particles with a size of 2-5 nm.
The drawing shows the curves of the radial distribution of atoms in the products of thermal decomposition (A) and phases of pseudoboehmite (1) and bayerite (2) (B).
The study of x-ray amorphous phase by the method of radial distribution of electron density with the construction of the model curves for various oxide and hydroxide phases (drawing) has allowed to establish that the product CTA differs from THA product. It is especially noticeable distinction in the field of interatomic distances 4-6 A. This difference is due to the presence of a product CTA atomic bonds, characteristic for disordered/defective layered structure similar to the structure bayerite. According to NMR Al27the intensity of the lines belonging to the aluminium cations in 4, 5 and 6 coordinated state, in relation to oxygen in the product CTA differs from the similar distribution in THA product (A.Isupova, Yu.Yu.Tanashev, I.V.Kharina, E.M.Moroz et al. // Chemical engineering Journal 2005 v.107, issue 1-3, pp.163-169).
Product CTA has a high chemical activity, which speeds up subsequent hydration at the stage of synthesis of the catalyst in the presence of water in the acidic environment in pseudoboehmite.
These properties of the product contribute to obtaining a catalyst for the dehydrogenation of lower3-C5paraffins having high catalytic activity, selectivity, stability and mechanical strength at low abrasive properties.
Prepared using the product CTA catalyst contains as a promoter of alkali metal and at least one oxide compound of the metal selected from the group of Zr, Ce, U, in the amount of 0.05-5.0 wt.%; and the catalyst has the following composition, wt.% (in terms of oxide): oxide of chromium, 10 to 20, the connection of the alkali metal - 1-2, zirconium oxide is 0.05 to 5, the cerium oxide is 0.05 to 5, the uranium oxide is 0.05-5, the alumina - rest.
The task is also solved by a method of preparation of the catalyst.
The catalyst is prepared by combining the stages of the hydration product CTA in pseudoboehmite and deposition of the active component and modifying additives. Application components carried out by simultaneous impregnation product - CTA impregnating solution containing compounds of chromium, modifying additives del knogo metal and join one of the transition metals Zr, CE or U. When the preparation of the impregnating solution, the volume of water take approximately 30-40% more than required by the capacity of the media, taking into account the fact that an excessive amount of water consumed in the hydration product CTA in pseudoboehmite - AlOOH. The impregnation is carried out in a period of 1-4 hours at a solution temperature of 20 to 100°With (preferably 40-100° (C) with constant stirring in a closed volume at constant partial pressure of water vapor. The additional heat generated by exothermic reaction of hydration product-CTA in pseudoboehmite used in the preparation of large quantities of catalyst (weight ˜50 kg or more) for the subsequent drying of the catalyst. Drying of the catalyst is carried out for one hour with continuous stirring with the open propitiates.
The forming of the catalyst by calcination for 1-4 hours at a temperature of 700-780°preferably 750°C.
As starting substances for the preparation of the impregnating solution used chromic anhydride or solutions of chromic acid, hydroxides or carbonates of alkali metal chromates and/or bichromate alkali metal M2CrO4or M2Cr2O7, nitrates, chlorides, acetates or sulfates of zirconium and/or cerium.
According to XRD active component of the catalyst is and is microdispersed with particle size, equal to 2-5 nm, oxide α-Cr2O3solid solution of Cr3+in γ-Al2About3composition of Al(21,33-x)CrxAbout32where: x=0,1-2,67, cubic structure. Promoting additives of oxides of alkali metals, oxides of Zr, CE and/or U are x-ray amorphous state. The composition of the solid solution depends on the content of chromium in the catalyst and depth hydration oxygen-containing compound of aluminum General formula Al2O3·nH2O (n=0,1-2,0) pseudoboehmite. The composition of the solid solution was calculated from the change of the parameter cubic alumina phase in the catalyst with respect to parameter γ-Al2About3phase. Calculation of the lattice parameter was performed on a line (422) in the field 66.6-67.2 deg 2θ.
The phase composition of the original product CTA and catalyst were determined by the methods of x-ray phase analysis (XRD) and derivatographic (DTA). XRD was carried out on the apparatus HZG-4c in the field angles from 10 to 80 degrees on 2θ with computer recording the results. DTA was carried out on the machine NETZSCH STA 449C with a heating rate of 10 deg/min
The morphological shape of the catalyst particles was controlled by the method of raster scanning electron microscopy (SEM) microscope brand JSM-6460 LV (Jeol).
Specific surface area and porous structure of the original products CTA and catalysts on regulaly on the machine company Quantachrome Corporation on adsorption and desorption of nitrogen. To calculate the magnitude of the specific surface area BET, pore size and distribution of pore sizes was performed with the program "Gas Sorpsion Report Autosob for Windows for AS-3 and AS-6" Version 1.23.
Fractional composition of the catalyst was determined by laser scattering instrument Shimadzu SALD 2101.
Chemical analysis of the catalyst was performed by atomic absorption apparatus Saturn.
The task is also solved by a process for the dehydrogenation of C3-C5-paraffin hydrocarbons (isobutane or propane) olefinic hydrocarbons, which is carried out in a fluidized layer of the above-described catalyst in catalyst circulation along the contour: the dehydrogenation reactor - reactor regeneration. The temperature of the dehydrogenation 520-610°C, the temperature of regeneration - 560-650°C, the volumetric feed rate of 400-800 h-1time dehydrogenation 10-30 min, the regeneration time of 5-30 min, purge time the inert gas between stages of dehydrogenation - regeneration - dehydration - 3-15 minutes
The invention is illustrated by the following examples.
Example 1. 40 kg technical hydrate of alumina (hydrargillite) with initial moisture content of 4.5% and a temperature of 25°served with a speed of 15 kg/h heated to 450°With the plate, the contact time 1.5 C. the resulting product CTA Tsevaot on the sieve of 70 μm.
Chemical and phase composition and texture characteristics polucen the th media are shown in table 1.
The product fraction size 70-250 μm serves on the stage of impregnation.
Prepare an impregnating solution with the desired composition of the catalyst based on oxides, wt.%: chrome - 16, K - 1,5, zirconium - 1.0, alumina rest. In a container with stirring to sleep with 21.3 g of chromic anhydride, 1.9 grams of potassium hydroxide, 3.03 g of zirconium carbonate and poured 1.25 ml of concentrated nitric acid and distilled water to obtain the estimated volume of impregnating solution. The solution is heated to a temperature of 40-60°C.
94,2 g sifted product CTA is placed in a mixer with a Z-shaped blades and poured obtained impregnating solution. Impregnation lead for 1 hour, then the impregnated mass is discharged from the mixer and dried in an oven at 100-120°C for 24 h and calcined in a muffle furnace at a temperature of 750°C for 1 h
Data on chemical composition, textural characteristics and catalytic properties of the samples are shown in table 2.
Example 2. The preparation of a carrier and a catalyst is prepared analogously to example 1, the difference is that in the impregnating solution is added to the cerium nitrate to obtain in the finished catalyst 1 wt.% cerium oxide.
Example 3. The preparation of a carrier and a catalyst is prepared analogously to example 1, the difference lies in the fact that impregnated the full solution add nitrate of uranium to obtain in the finished catalyst 1 wt.% uranium oxide.
Example 4. 40 kg technical hydrate of alumina (hydrargillite) with initial moisture content of 4.5% and a temperature of 25°served with a speed of 15 kg/h heated to 650°With the plate, the contact time 1.5 C.
Preparation of the catalyst is carried out analogously to example 1.
Example 5. 100 kg technical hydrate of alumina, with an initial moisture content of 4.5% and a temperature of 25°served with a speed of 43 kg/h heated to 550°With the plate. The resulting product CTA Tsevaot on the shale shakers 70 μm. The resulting product fraction size 70-200 μm serves on the stage of impregnation.
Prepare an impregnating solution analogously to example 1. The difference lies in the fact that they use the following sample damage components in terms of oxides:
chromic anhydride - 11,1 kg
the potassium oxide - 0,94 kg
zirconium oxide - 0,52 kg
water - 4,9 liters
The total volume of impregnating solution of 8.8 liters of This solution is impregnated with 48 kg of product CTA size part 70-250 μm. The mass ratio of liquid:solid = 0,183.
In the Z-shaped mixer pour impregnating solution, the impregnation was carried out under continuous stirring at the closed lid of the mixer to raise the temperature of the impregnating solution to 90-100°C due To the exothermic hydration reaction product CTA. Then open the lid of the mixer, and conducting drying at 100-80°With continuous paramashiva the AI to the formation of the granular mass. The dried catalyst is calcined at 750°1 p.m.
Example 6. 100 kg technical hydrate of alumina, with an initial moisture content of 4.5% and a temperature of 20°served with a speed of 37 kg/h heated to 550°With the plate. Preparation of the catalyst is carried out analogously to example 5. The difference lies in the fact that the ratio of liquid:solid - 0,198.
Example 7. 100 kg technical hydrate of alumina, with an initial moisture content of 4.5% and a temperature of 20°served with a speed of 40 kg/h heated up to 450°With the plate.
Preparation of the catalyst is carried out analogously to example 5. The difference lies in the fact that the ratio of liquid:solid - 0,239.
Example 8. 40 kg technical hydrate of alumina is served with a speed of 15 kg/h heated to 400°With the plate, the contact time of 1.5 C. the resulting product Tsevaot on the sieve of 70 μm. Received the product fraction is larger than 70 μm, and serves on the stage of impregnation.
Preparation of the catalyst is carried out analogously to example 1.
Example 9. Product CTA receive analogously to example 8. Preparation of the catalyst is carried out analogously to example 1. The difference is that the sizing on the screens of different sizes prepare the catalyst of the next fractional composition, wt.%: <50 μm - <30%; 50 to 80 μm - 20-30%; 80-100 μm - 15-25%; 100-120 μm - 15-20%; 120-140 µm - 10-15%; >140 μm <5%.
Example 10 (prototype).
The compound of aluminium of the formula Al2About3·nH
|Characteristics of the source of oxygen-containing compounds of aluminum Al(OH)x·nH2O|
|Example||SPT, wt.%||The content phase, wt.%||Al2O3(HE)x·nH2O||SUD,m2/g||Vlongcm3/g|
|GG - hydro-argillite|
|Be - boehmite|
|Composition, physicochemical and catalytic properties of the catalysts in the dehydrogenation reaction of isobutane and propane in a fluidized bed|
|Example||Fractional composition of,|
mcm - wt.%
|SUD, m2/g||Vlong< / br>cm3/g||Losses abrasion for 1 h wt.%||Content, wt.%||Catalytic characteristics at|
|EAP wt.%||BP wt.%||X %|
|1||70-90 - 6%||132||0,16||4||15,7||1,5||1,0||-||-||54,6||91,9||to 59.4|
|91-160 - 66%|
|161-200 - 28%|
|4||70-90 - 8%||114||0,17||3||16,6||1,5||53,2||90,0||59,2|
|91-160 - 60%|
|161-200 - 32%|
|5||70-90 - 1.0%||101||0,17||5||11,8||1,7||1,0||-||-||54,3||for 91.3||59,5|
|161-200 - 38%|
|6||70-90 - 0%||84||0,15||8||15,4||1,7||1,0||-||-||55,4||92,0||60,2|
|91-160 - 66%|
|7||70-90 - 0%||98||0,17||4||17,1||1,7||1,0||-||-||54,6||92,3||59.1|
|8||70-90 - 6%||102||0,17||5||16,0||1,5||1,0||-||-||50,4||92,8||54,3|
|91-160 - 78%||36,0*)||88,7*)||40,6*)|
|161-200 - 28%||Ȋ|
|9||<5 - <30%||102||0,17||7||16,0||1,5||1,0||-||-||53,1||93,2||57,0|
|50-80-20 - 30%|
|80-100-15 - 25%|
|100-120-15 - 20%|
|120-140-10 - 15%|
|>140 - <5%.|
|The placeholder||100-200 - 100%||100||3,4||18||3,0||1,0||Niobium - 1,0||52||92||56,5|
|EAP - out of isobutylene on missed isobutane|
|*) the yield of propylene missed on propane|
|BP - out of isobutylene to spread out isobutane (selectivity)|
|*) the yield of propylene in the unfolded propane|
|X is the degree of conversion of isobutane|
|*) the degree of conversion of propane|
1. The dehydrogenation catalyst With3-C5-paraffin hydrocarbons into olefins containing chromium oxide, alkali metal oxide, transition metal oxides, and the media, wherein the media it contains nanostructured oxygen-containing compound of aluminum General formula Al2O3(HE)x·nH2O, where x=0-0,28, n=0,03-1,8 consisting of nanostructured primary particles of 2-5 nm in size and characterized by time is porjadochnoi/defective layered structure, close to the structure bayerite.
2. The catalyst according to claim 1, characterized in that the oxygen-containing compound of aluminum General formula Al2O3(OH)x·nH2O get in nonequilibrium conditions by rapid centrifugal termoparnaya processing of aluminum hydroxide in saturated water vapor at elevated temperature, followed by forced cooling of the obtained product.
3. The catalyst according to claim 2, characterized in that as the source of aluminum hydroxide use hydro-argillite (gibbsite or bayerite.
4. The catalyst according to claim 1, characterized in that it contains, wt%: an 8.0-23.0 chromium oxide Cr2About3; 0,05-5,0 oxide of an alkali metal M2About; 0,1-5,0 oxide of the transition metal M O2the rest of the media.
5. The catalyst according to claim 1, characterized in that the alkali metal M selected from a number of: Li, Na, K, Rb, Cs.
6. The catalyst according to claim 1, characterized in that the transition metal M' selected from the series: Zr and/or CE, and/or U.
7. The catalyst according to claim 1, characterized in that it represents the microspheres, with the following distribution of particle size, wt.%.: <50 μm - <30; 50-80 μm - 20-30; 80-100 μm - 15-25; 100-120 μm - 15-20; 120-140 µm - 10-15; >140 μm <5.
8. The catalyst according to claim 1, characterized in that the active component is microdispersed with a particle size equal to 2-5 nm, oxide α-Cr2About3solid R is the target Cr 3+in γ-Al2About3composition of Al(21,33-x)CrxAbout32where x=0,1-2,67, cubic structure.
9. The preparation method of catalyst for the dehydrogenation of C3-C5-paraffin hydrocarbons into olefins containing chromium oxide, alkali metal oxide, transition metal oxides, and the media, making connections active components and modifying additives on the carrier, drying and calcination, characterized in that as the carrier used oxygen-containing compound of aluminum General formula Al2O3(OH)x*nH2O, where x=0-0,28, n=0,03-1,8 consisting of nanostructured primary particles of 2-5 nm in size and characterized by disordered/defective layered structure similar to the structure bayerite.
10. The method according to claim 9, characterized in that the oxygen-containing compound of aluminum General formula Al2O3(OH)x·nH2O get in nonequilibrium conditions by rapid centrifugal termoparnaya processing of aluminum hydroxide in saturated water vapor at elevated temperature and subsequent forced cooling and subsequent hydration at the stage of impregnation of the active compounds of components and modifiers.
11. The method according to claim 10, characterized in that as the source of aluminum hydroxide used hydrargyri the (gibbsite or bayerite.
12. The method according to claim 10, characterized in that the hydration of oxygen-containing aluminum compounds is carried out at a temperature of 40-100°in a closed vessel under stirring in the presence of water vapor.
13. The method according to any of PP and 10, characterized in that the heat released during the hydration of oxygen-containing compounds of aluminum impregnating solution used for the subsequent drying of the resulting catalyst at a temperature of 80-100°in open vessel with constant stirring.
14. The method according to claim 9, characterized in that compounds active ingredients containing chromium use such as chromic acid, chromates and/or bichromate alkali metal M2CrO4or M2Cr2O7.
15. The method according to claim 9, characterized in that as chromates or bichromates alkali metals use chromates and/or bichromate alkali metal selected from the range of: Li, Na, K, Rb, Cs.
16. The method according to claim 9, characterized in that compounds containing the modifying additive, use of nitrates, chlorides, acetates or sulfates cation M O2+the transition metal M' selected from a number of: Zr, Ce, U.
17. The method according to claim 10, characterized in that the hydration of oxygen-containing compounds of aluminum to 100 weight parts of the product of the centrifugal termoparnaya processing of aluminum hydroxide is dobavlaut 18-25 weight parts of a solution, containing 14-20 parts of water, chromic acid, chromate and/or bichromate of alkali metal M2CrO4or M2Cr2About7, nitrate, chloride, acetate, or sulfate cation M O2+
18. The process of dehydrogenation With3-C5-paraffin hydrocarbons into olefins, wherein the catalyst using the catalyst according to claims 1 to 8, or cooked PP-17.
19. The process p, characterized in that it is carried out in a fluidized bed of catalyst in catalyst circulation along the contour of the dehydrogenation reactor - reactor regeneration.
20. The process according to any one of p and 19, characterized in that the temperature of the dehydrogenation 520-610°C, the temperature of regeneration 560-650°C, the volumetric feed rate of 400-800 h-1time dehydrogenation 10-30 min, the regeneration time of 5-30 min, purge time the inert gas between stages of dehydrogenation - regeneration of the dehydrogenation 3-15 minutes
FIELD: hydrogenation-dehydrogenation catalysts.
SUBSTANCE: invention relates to methods of preparing alumino-chromium catalysts for dehydrogenation of paraffin hydrocarbons, preferably С2-С5, into corresponding olefins using low-temperature plasma. Plasma-chemical method for preparing catalyst comprises heat treatment of starting reactants taken in the form of aluminum and chromium carbonyl powders in the flow of low-temperature air plasma, said reactants being fed separately to the air plasma stream and to reactor in the form of argon-carried air sol in amount large enough to obtain catalyst containing 10-25% chromium oxide and 75-90% aluminum oxide. Resulting catalyst is cooled in the form of dust-gas stream to 30-50°C and recovered.
EFFECT: increased productivity of procedure, yield, and purity of target material, and increased catalyst activity.
FIELD: hydrogenation-dehydrogenation catalysts.
SUBSTANCE: invention relates to methods of preparing alumino-chromium catalysts and their compositions for dehydrogenation of С2-С5-paraffin hydrocarbons into corresponding olefins. A method for preparing above-said alumino-chromium catalyst and catalyst prepared by this method are disclosed. Method comprises providing saturated solution of water-soluble chromium and aluminum salts, heating solution to 80-90°C, precipitating alumino-chromium hydroxide by passing ammonia gas through saturated solution until pH 9.5-10 is attained, drying resulting slurry of hydroxides at 100-120°C and subsequent calcination of dry powder for 5 h at temperature not higher than 550°C. Starting components are taken in such amounts as to ensure, after calcination, contents of chromium oxide 10-30% (the rest: aluminum oxide). Chromium oxide is composed of chromium(VI) and chromium(III) oxides, wherein proportion of chromium(VI) oxide in chromium oxide mixture is at least 20 wt %.
EFFECT: simplified catalyst preparation procedure and increased activity and selectivity of catalyst in paraffin hydrocarbon dehydrogenation process.
4 cl, 2 ex
FIELD: industrial organic synthesis.
SUBSTANCE: invention relates to an isoprene production process involving dehydrogenation of isoamylene fraction in presence of overheated steam and iron oxide-based catalyst and is characterized by that catalyst has loose density at least 1.0 g/cc and not higher than 2.00 g/cc, apparent density at least 2.0 g/cc and not higher than 3.5 g/cc, and following composition. wt %: potassium compound 5-30, magnesium oxide 0.5-10, cerium(IV) oxide 5-20, calcium carbonate 1-10, molybdenum oxide 0.5-5, and ferric oxide - the rest.
EFFECT: improved selectivity of dehydrogenation process and increased activity and service cycle of catalyst.
2 cl, 1 tbl, 7 ex
FIELD: hydrogenation-dehydrogenation catalysts.
SUBSTANCE: invention provides catalyst based on iron oxide and lanthanide compound wherein at least part of iron oxide is prepared via a method including thermal decomposition of iron halide and which contains lanthanide in amount corresponding to 0.07 to 0.15 mole per mole iron oxide found in catalyst (calculated as Fe2O3). A catalyst is also described wherein part of iron oxide contains residual halide. Preparation of catalyst involves providing a mixture containing sufficient amounts of at least iron oxide and lanthanide compound followed by calcination of the mixture. Alkylaromatic compound dehydrogenation process is further described involving contact of raw feed containing alkylaromatic compound with above-described catalyst as well as polymer or copolymer production process involving production of alkenylaromatic compound as described above and subsequent polymerization thereof or copolymerization with a monomer.
EFFECT: enabled production of alkenylaromatic compounds with improved characteristics owing de decreased formation of by-products.
18 cl, 2 ex
FIELD: petrochemical process catalysts.
SUBSTANCE: reaction gas is passed in reaction zone through at least one fixed catalyst bed wherein reaction gas is subjected to dehydrogenation to produce molecular hydrogen and at least one dehydrogenated hydrocarbon. Reaction gas, before and/or after entering reaction zone, is supplemented by at least one molecular oxygen-containing gas, which partially oxidizes molecular hydrogen contained in reaction gas to form water steam. Gas product containing molecular hydrogen, water steam, at least one dehydrogenated hydrocarbon, and at least one hydrocarbon to be dehydrogenated is withdrawn from reaction zone, and divided into two parts, one of which is recycled into reaction zone.
EFFECT: simplified process and increased propylene formation selectivity.
12 cl, 2 dwg, 3 tbl, 4 ex
FIELD: petrochemical processes.
SUBSTANCE: invention concerns reactor with fluidized bed of fine catalyst, which reactor contains upright cylindrical body, sectioning grids with their free area increasing along the height of reactor, connecting pipes for supplying feedstock and evacuating contact gas, and receiving and withdrawing recycled catalyst, and cyclones with dust-removing risers. More specifically, upper grid has free area larger than 60 and lesser than 90% of the body section, ends of connecting pipes receiving recycled catalyst and ends of dust-removing risers are disposed above upper grid and below fluidized bed.
EFFECT: increased output of reactor, improved performance of dehydrogenation (increased yield of olefins and reduced consumption of catalyst), and improved environmental condition.
FIELD: petrochemical processes.
SUBSTANCE: feed stream is passed with admixed oxygen and diluent through catalyst bed at 400-500°C and constant flow rate 50 mL/min, said catalyst being catalytic system for heterogeneous reactions and representing geometrically structured system including microfibers of high-silica fibrous carrier, which is characterized by presence in IR absorption band of hydroxyl groups with wave number ν=3620-3650 cm-1 and half-width 65-75 cm-1. The carrier has specific surface as measured according to BET method from heat desorption of argon SAr=0.5-30 m2/g, surface area as measured by alkali titration method SNa=5-150 m2/g at ratio SNa/SAr=5-50, and at least one active element, whose principal portion is composed in the form of charged either metallic, or bimetallic clusters characterized in UV-vis diffuse reflection spectrum by specific bands in the region 34000-42000 cm-1 and ratio of integral intensity of band attributed to charged either metallic, or bimetallic clusters to integral intensity of band belonging to, respectively, either metallic, or bimetallic particles is not less than 1.0.
EFFECT: increased choice of oxidative dehydrogenation catalysts.
4 cl, 5 ex
FIELD: petrochemical processes.
SUBSTANCE: branched olefins are obtained via dehydrogenation of isoparaffin composition containing 0.5% or less quaternary aliphatic carbon atoms in presence of suitable catalyst. Isoparaffin composition is prepared via hydrocracking and hydroisomerization of paraffin wax and contains paraffins with 7 to 18 carbon atoms, these paraffins or at least a part of them are branched with average number of branches between 0.5 and 2.5 per paraffin molecule, the branches including methyl and optionally ethyl ones. Original paraffin wax is prepared using Fischer-Tropsch reaction. Resulting branched olefins are characterized by content of quaternary aliphatic structures 0.5% or less. Branched aromatic hydrocarbon and compositions of branched olefins, branched aromatic hydrocarbon, and branched alkylarenesulfonates are also disclosed.
EFFECT: improved quality characteristics of target products.
10 cl, 19 ex
FIELD: petrochemical processes.
SUBSTANCE: branched olefins are obtained via catalytic dehydration of isoparaffin composition including 0.5% or less of quaternary aliphatic carbon atoms. This isoparaffin composition comprises paraffins with number of carbons within a range of 7 to 35, said paraffins or at least a part thereof being branched with average number of branches from 0.7 to 2.5 and said branches including methyl and optionally ethyl branches. Indicated isoparaffin composition with is obtained via hydrocracking and hydroisomerization of wax. Thus obtained branched olefins contain 0.5% or less of quaternary aliphatic carbon atoms.
EFFECT: upgraded quality characteristics of desired products.
8 cl, 4 tbl, 11 ex
FIELD: industrial organic synthesis.
SUBSTANCE: ethylbenzene blend obtained through blending fresh ethylbenzene and recycled ethylbenzene with styrene content not above 0.1 wt % is subjected to catalytic dehydrogenation in presence of water steam at feed-to-steam weight ratio 1:2, temperature 600°C, ethylbenzene blend supply space velocity 0.5-1.0 h-1, and reactor pressure maintained within a range of 45 to 80 kPa absolute. Multistep rectification gives rectified styrene with concentration of desired product at least 99.8% and phenylacetylene impurity level not higher than 0.01 wt %. Recycled ethylbenzene is blended with fresh ethylbenzene and resulting ethylbenzene blend containing no more than 0.1 wt % styrene is supplied to dehydrogenation unit.
EFFECT: increased ethylbenzene-to-styrene conversion, improved process selectivity, and reduced level of phenylacetylene in commercial product.
FIELD: instrument engineering; protective coatings for the components of the electronic equipment.
SUBSTANCE: the invention is pertaining to the field of instrument engineering. The technical result of the invention consists in the development of the protective coating having the high persistence to the action of the ionizing radiations at the small specific gravity of the structure. The substance of the invention consists that the protective coating is made in the form of the nanostructure. The nanostructure includes the totality of the atoms of the rare-earth elements introduced into the structure of the reinforcing is atomic-molecular metallic matrix array. The nanostructure may be the constituent part of the protected structure or the protective coating of the structure.
EFFECT: the invention ensures the development of the protective coating having the high persistence to the action of the ionizing radiations at the small specific gravity of the structure.
FIELD: chemical industry; production of the nanocomposite materials on the basis of the high-molecular compounds with application of carbon in the nanostucturized coatings.
SUBSTANCE: the invention is pertaining to the composite materials on he basis of the high-molecular compounds with usage of the carbon in the nanostructurized coatings including the additional devices and connections, and may be used as the anode of the electrolytic capacitor due to storage of the electrical potential in the current-carrying layers. The nanostructurized coating of the current-carrying basis is bound directly to the layer of the amorphous carbon sp3 - the hybridized state of the carbon atoms and additionally has the metal layer with the depth of 25-250 nanometers. The surface of the film basis has a flutings of 10-30 nanometers depth and-or is equipped with the pores of 0.2-6 microns and the total volume of 10-60 %. At that 1/5-1/3 part of the pores is through. The invention ensures the adhesion bond and improvement of the electro-physical performances of the material.
EFFECT: the invention ensures the adhesion bond and improvement of the electro-physical performances of the material.
FIELD: polymer materials.
SUBSTANCE: invention relates to composite materials based on high-molecular weight carbon-involving compounds and can be used for anodes of electrolytic condensers made from dielectric elastic film with current-conducting coating. Polyester-based film material has nano-sized metallic coating. A diamond-like layer 5-50 nm thick is disposed between modified surface of polyester base and metallic coating and, on the surface of metallic coating, spongy aluminum layer is deposited having surface development factor within a range of 80 to 400. Diamond-like nanolayer is characterized by sp3 hybridization of amorphous carbon atoms, amorphous carbon being deposited in vacuum from gas phase under action of ion-plasma source.
EFFECT: increased specific electrical capacity of condenser due to increased operation voltages and adhesion between high-developed surfaces of functional film coating nanolayers.
FIELD: manufacture of thin-layer films used in electronics, non-linear optics and magnetism.
SUBSTANCE: proposed substrate is coated with composite film on base of meso-porous inorganic layer containing nano-particles forming in-situ inside layer. Composite film has structure of periodic lattice in larger part of layer where nano-particles are present; nano-particles are arranged in periodic pattern in domain scale in at least four periods of film thickness. This structure may be obtained from meso-porous inorganic layer of periodic structure in domain scale in at least four periods of pores forming matrix on substrate by settling of at least one precursor in pores of matrix layer and growth of particles obtained from precursor at monitoring spatial distribution and sizes of structure of matrix pores.
EFFECT: possibility of obtaining material in form of layer containing nano-particles of regular structure.
26 cl, 5 dwg
FIELD: physics of semiconductors, in particular, engineering of semiconductor nano-structures with quantum wells, possible use for realization of powerful semiconductor devices.
SUBSTANCE: semiconductor nanostructure contains quantum well with two-dimensional electron gas, made in form of layer of narrow-zoned semiconductor i-GaAs with forbidden zone Eg1 having thickness d1 and levels of dimensional quantizing Em1 - main and Ep1 - excited, sandwiched between two layers of semiconductor AlxGa1-xAs with forbidden zone Eg2>Eg1 and main level of dimensional quantizing Em2 having thickness d2 each, which is positioned between two barrier layers of wide-zoned semiconductor i-AlAs with thicknesses temperature and differentsp and forbidden zone Eg, one of which contains δ-Si layer of admixture at distance t* from hetero-boundary i-AlAs and i-AlxGa1-xAs, and second one consists of non-alloyed i-AlAs spacer and layer AlAs(Si) alloyed homogeneously by silicon and layer i-GaAs covering the nanostructure. In composite quantum well of semiconductor nanostructure, formed on poly-insulating substrate GaAs(Cr) in form of serial layers i-GaAs(buffer)/i-AlAs(δ-Si)/i-ALxGa1-xAs/i-GaAs/i-AlxGa1-xAs/i-AlAs. By special selection of parameters Eg>Eg2>Eg1 and relation d1/d2, condition Em2<Ep1 is maintained as well as localization of two-dimensional electrons with maximum in center of symmetry of composite quantum well on levels Em1 and Em2.
EFFECT: increased mobility of μt 2D electrons in quantum well with simultaneous increase of concentration nS.
4 cl, 4 dwg
SUBSTANCE: proposed sensor component that uses axial symmetry to impart magnetic properties to materials has magnetic material in the form of nanomagnets whose sides measure 40 - 500 nm and thickness is 3 - 10 nm; they function as zero-hysteresis superparamagnetic components.
EFFECT: use of configurational anisotropy through component symmetry to set magnetic properties and to ensure zero hysteresis.
3 cl, 8 dwg
FIELD: optics; coherent electromagnetic radiation systems.
SUBSTANCE: novelty is that metal, such as silver, nanoparticles whose plasma resonance frequency is close to frequency of transfer of mentioned active particles to inverted population level are additionally placed in prior-art amplifier on quantum (active) points.
EFFECT: enhanced gain for low and high strengths of fields being amplified.
1 cl, 2 dwg, 1 ex
FIELD: electronic engineering.
SUBSTANCE: proposed substance related to materials acting on electromagnetic fields so as to control and change them and can be used for producing materials with preset optical, electrical, and magnetic characteristics has in its composition active-origin carrier in the form of clusters of atoms, nanoparticles, or microparticles, its insulating function being checked in the course of manufacture; this function is characteristic controlling interaction between substance and electromagnetic field.
EFFECT: improved characteristics of heterogeneous substance.
FIELD: magnetic materials whose axial symmetry is used for imparting magnetic properties to materials.
SUBSTANCE: memory element has nanomagnetic materials whose axial symmetry is chosen to obtain high residual magnetic induction and respective coercive force. This enlarges body of information stored on information media.
EFFECT: enhanced speed of nonvolatile memory integrated circuits for computers of low power requirement.
4 cl, 8 dwg
FIELD: alternative fuels.
SUBSTANCE: invention relates to catalysts and process of steam conversion of hydrocarbons to produce synthesis gas. Proposed catalyst for steam conversion of hydrocarbons contains nickel oxide (4.0-9.2%) and magnesium oxide (4.0-6.5%) supported by porous metallic nickel (balancing amount). Carrier has specific surface area 0.10-0.20 m2/g, total pore volume 0.07-0.12 cm3/g, predominant pore radius 1-30 μm, and porosity at least 40%. Described are also catalyst preparation method and generation of synthesis gas via steam conversion of hydrocarbons.
EFFECT: increased heat conductivity of catalyst resulting in stable activity in synthesis gas generation process.
8 cl, 1 tbl, 5 ex