Catalyst, method for preparation thereof, and a method for dehydration of hydrocarbons using this catalyst
FIELD: hydrogenation-dehydrogenation catalysts.
SUBSTANCE: invention relates to production of olefin or diolefin hydrocarbons via dehydrogenation of corresponding paraffinic C3-C5-hydrocarbons carried out in presence of catalyst comprising chromium oxide and alkali metal deposited on composite material including alumina and aluminum wherein percentage of pores larger than 0.1 μm is 10.0-88.5% based on the total volume of open pores equal to 0.10-0.88 cm3/g. Preparation of catalyst involves treatment of carrier with chromium compound solution and solution of modifying metal, preferably sodium or sodium and cerium. Carrier is prepared by from product resulting from thermochemical activation of amorphous hydrargillite depicted by formula Al2O3·nH2O, where 0.25<n<2.0, added to homogenous mass in amount 1.0 to 99.0% using, as additional material, powdered aluminum metal, which is partly oxidized in hydrothermal treatment and calcination stages. Hydrocarbon dehydrogenation process in presence of the above-defined catalyst is also described.
EFFECT: increased activity and selectivity of catalyst.
3 cl, 2 dwg, 4 tbl, 7 ex
The invention relates to the field of production of olefinic or diolefines hydrocarbons by dehydrogenation of the corresponding paraffin With3-C5hydrocarbons and may find application in the chemical and petrochemical industries.
A method of obtaining olefinic hydrocarbons by dehydrogenation in the presence of a catalyst composition, wt.%: CR2O3- 10,0-30,0; ZnO - 30,0-45,0; Al2About3- the rest [U.S. Pat. Of the Russian Federation No. 2178398, C 07 C 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.
The known process of dehydrogenation of paraffin hydrocarbons in the presence of a chromium catalyst composition, wt.%: CR2About3- 10,0-20,0;2About3- 1,0-1,5; IU2O - 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° [U.S. Pat. OF THE RUSSIAN FEDERATION NO. 2156233, C 07 C /333, 2000].
The processes described above is carried out in a fluidized bed.
Closest to the present invention is a catalyst for the dehydrogenation process in a fixed bed composition, wt.%: CR2O3- 15,0-25,0); Me (alkali metal) ≤ 0,5; Al2O3- the rest [U.S. Pat. UK No. 2162082, B 01 J 23/26, 21/04, 1985]. As a carrier for the catalyst used granules Al2About3size ~3 mm, an apparent density of 1.36 g/cm3the true density of 3.53 g/cm3, bulk density 0,836 g/cm3total pore volume 0,435 cm3/g, an average pore size of 11 nm. Maximum performance isobutene is 59.5% at a flow rate of isobutene 367 h-1and a temperature of 620° C. the Disadvantage of this catalyst is the lack (or small number) in the medium then large (>100 nm) size - 1.5% of the total volume of open pores, which is determined from the difference between inverse values of apparent and true density of the granules media [Kinetics and catalysis, 2000, Vol.41, B.6, s]. The absence of pores of large size is reflected in a very low average pore size (table 1), which leads to a diffusion inhibition of gaseous reactants and reaction products. The latter leads to the reduction performance of the catalyst and the deterioration of the characteristics of the process of dehydrogenation of hydrocarbons in General. UTS is DTIE metal in the composition of the medium can lead to local overheating and greater coking of the catalyst.
The increase of pores of large size granules media possibly adding in pasta-extrudate or powdery mixture of large particle size or particle viraemic at burning supplements. However, this usually leads to a significant reduction in the mechanical strength and reduce the apparent density of the granules. The last value is usually corallium with a bulk density of pellets and determines the efficiency of a unit volume of reaction space, which is crucial when replacing one catalyst to another.
The invention solves the problem of increasing the efficiency of the process of dehydrogenation of olefinic hydrocarbons through the use of catalyst-based carrier having a sufficiently large proportion of pores of large size while maintaining a high apparent strength of the granules. When this goal is to maintain high activity of the catalyst due to the high specific surface of the carrier to increase the dispersion of the active component when it is applied by impregnation, and also increase thermal conductivity of pellets of the catalyst due to the presence of metal particles in the media.
The task is solved in that:
a) a ceramic matrix, providing mechanical strength of the medium, has a high specific surface area;
b) material of diperkirakan the second ceramic matrix media does not have a high specific surface area and represents the metal aluminum. When the total volume of open pores of the carrier 0,10-0,88 cm3/g proportion of macropores larger than 0.1 ám is about.%: 10,0 88.5 in.
The catalyst prepared using the above media, contains chromium oxide with additives of alkali metal, preferably sodium or sodium and cerium oxide.
The task is also solved by a method of preparation of a catalyst for the dehydrogenation process.
For the preparation of the catalyst containing the oxides of chromium and aluminum in the prototype [U.S. Pat. UK No. 2162082, B 01 J 23/26, 21/04, 1985] based media aluminum oxide impregnated with solutions containing compounds of chromium and alkali metal, followed by drying and calcination.
In the proposed method as a carrier using a composition containing aluminum oxide and aluminum, with the parameters of the porous structure described above, which is impregnated with solutions of chromium compounds and sodium or chromium, sodium and cerium. The media are synthesized from a powder mixture comprising powdered aluminum and adhesive component is a product of thermochemical activation trihydroxide aluminum (THA) in an amount of 1.0 to a 99.0 wt.%. The mixture is poured into a special mold, permeable to water vapor. The mold with the mixture treated with the hydrothermal conditions. After hydrothermal treatment of the obtained granulated product is removed from the mold, dried and calcined. The resulting carrier containing aluminum oxide of the gamma-, ETA-, theta - and other modifications and aluminum, the remaining unoxidized after hydrothermal treatment and annealing. The proportion of pores with a diameter of more than 0.1 μm is 11,0 was 87.5% vol. of the total pore volume of the carrier.
Product THA used to prepare the mixture, obtained by dehydration under conditions of pulsed heating process of hydrate of alumina - hydrargillite Al(Oh)3[Zolotovskiy BP, Buyanov R.A., Balashov, VA, Krivoruchko OP// Scientific basis of preparation of the catalysts. Collection of scientific papers. Novosibirsk; Institute of catalysis SB RAS. 1990. S]. Thus obtained product THA is amorphous and has a composition of Al2About3·mo2O, where is 0.25<n<a 2.0. The product has high reactivity, and is easily hydrated in the presence of water or vapor environment with the formation of aluminum hydroxide pseudoboehmite patterns l. Product introduction THA batch provides extra strength and high specific surface area of the granules. Aluminum in partial oxidation in hydrothermal conditions provides a seal granules while maintaining high proportion of macropores and increase their diploproa the property.
The properties of these media are given in table 1. The true density of the pre-milled granules determined based way. The volume of pores smaller than 100 nm and a specific surface area determined from isotherms-adsorption of nitrogen. For comparison, the properties of the medium on the basis of aluminum oxide from a prototype [U.S. Pat. UK No. 2162082, B 01 J 23/26, 21/04, 1985]. As can be seen from table 1, compared to a net product of THA and aluminium fraction of macropores in carriers, obtained by blending less. However, the specific surface area and apparent density of the granules in carriers obtained by mixing, as a rule, increases. This is reflected in the non-monotonic change of the bulk density of the granules. An optimum value of specific surface area and apparent density are compounds containing 40-80 wt.% product THA in the original charge. Qualitatively the presence of a large number of pores with a size of 1-10 μm is illustrated in Figure 1.
Prepared by the method described above, the carrier is calcined in a stream of air at temperatures of 600-1000° C, preferably 700-800° With, for 2-10 hours, preferably 4-6 h, and used for preparation caused oxenkrug catalyst. The catalyst is prepared by impregnating pellets of the carrier with an aqueous solution SGAs3on the capacity of the media. The concentration of chromic acid in the solution Russ is icyhot from the need to obtain in the finished calcined catalyst 12-25 wt.%, preferably 18-20 wt.%, CR2About3. Simultaneously with chromic acid in the impregnating solution is injected soluble salts modifying additives: sodium and cesium. The content of additives in terms of oxides is, wt.%: 0.2-1.0 Na2O, 0.1-2.0 SEO2.
After impregnation the catalyst is dried in air at room temperature for 12 h, then at 110° C for 6 h and calcined in air at 600 to 800° C for 4-6 hours Rise of temperature to the final temperature of the calcination is carried out at step exposure for 1-2 h at 400° C.
The invention is illustrated by the following examples.
Example 1. The catalyst is prepared by impregnation of 70 g of the carrier 46 (table 1) with the initial ratio of the components THA:Al=60:40 (wt.%) 40 ml of an aqueous solution containing 20,1 g SGAs3and 1,035 g NaNO3. The sample is dried in air at room temperature for 12 h, then in a heating Cabinet at 110° 6 h and calcined at 400° 1 h at 700° 4 hours
Example 2. The catalyst prepared according to example 1, but additionally in the impregnating solution add 2.181 g CE(NO)3·6N2O.
Example 3. The catalyst prepared according to example 2, but using the media 2 (table 1) with the initial value THA:Al=99:1 (wt.%).
Example 4. The catalyst prepared according to example 2, but using the media 3 (table 1) with the initial zootoxin who eat THA:Al=80:20 (wt.%).
Example 5. The catalyst prepared according to example 2, but using the carrier 4A (table 1) with the initial value THA:Al=60:40 (wt.%).
Example 6. The catalyst prepared according to example 2, but using the media 5 (table 1) with the initial value THA:Al=40:60 (wt.%).
Example 7. The catalyst prepared according to example 2, but using the media 7 (table 1) with the initial value THA:Al=1:99 (wt.%).
The catalyst was tested in the reactions of dehydrogenation of propane, isobutane and n-butane at a temperature of from 540 to 620° C. the dehydrogenation Process is carried out in a flow quartz reactor in a stationary catalyst bed with a fraction size of 2.5-3.5 mm. Granules of the catalyst are uniformly mixed with quartz granules of the same size in the ratio of catalyst:quartz=1:1. Testing is carried out both at atmospheric and reduced partial pressure negidrirovannogo hydrocarbon. The reduction in the partial pressure of the hydrocarbon hold due to its dilution with helium. Gas volumetric feed rate of the hydrocarbon range from 150 to 1200 h-1. The process carried out by the cycles in the following sequence: dehydration - 12 min, purge with an inert gas to 10 minutes, the regeneration air is 15 min, purge with an inert gas to 10 minutes, and then the cycle is repeated. The degree of conversion, the yield of olefin to missed and decomposed (selectivity) hydrocarbon assessed the t by gas chromatographic analysis of the sample, taken ten minutes after the beginning of the dehydrogenation.
Figure 2 and in tables 2-4 presents data on the catalytic properties of the catalysts prepared according to examples 1-7 in the reactions of dehydrogenation of isobutane, propane and n-butane.
Figure 2 presents the dependence of the selectivity to isobutene from the degree of conversion of isobutane to the claimed catalyst on a carrier of alumina of Karamata (1) and prototype (2). 1 - example 2 (medium 4B, THA:Al=60:40 wt.%, table 1).
The test results show that in the reaction of dehydrogenation of isobutane at comparable temperatures (580-590° (C) proposed in the present invention, the catalyst has a significantly higher activity and selectivity than the catalyst taken as a prototype. The maximum yield of the product offer of the catalyst and process based on it (67,7%) significantly exceeds the maximum output product prototype (59,5%). The output of isobutene exceeds the output product prototype in the whole studied range of degrees of conversion of isobutane. In the reaction of dehydrogenation of propane at similar conditions, the tests offer us the catalyst has a yield of propylene to 47.4% (610° C, 600 h-1table 3), while its nearest analogue output - 35,3% (620° C, 600 h-1) [U.S. Pat. Of the Russian Federation No. 2178398, C 07 C 5/333, 1999].
The characteristics of the media.
|No.||The contents of THA in the charge wt. %||The apparent density of the granules, g/cm3||The true density of the granules, g/cm3||Total pore volume, cm3/g||Pore volume of less than 0.1 μm, cm3/g||The proportion of macropores (>0.1 ám), %||Specific surface area, m2/g||The bulk density of pellets (2-3 mm), g/cm3||The mechanical strength of granules, MPa|
|*Hydrothermal treatment at 100° other examples 200° C.|
Dehydrogenation of propane on Cr2About3/Al2About3-Al catalyst (example 2, the carrier 4B, the ratio in the charge THA:Al=60:40 wt. %, table 1) at different temperatures and dilutions inert gas.
|Dilution With3H8:He volume||T°||Catalytic properties|
|V3H8h-1||V(C3H8+H) h-1||The degree of conversion %||Exit C3H6mol. %||Selectivity With3H6mol. %|
The dehydrogenation of n-butane on SG2About3/Al2About3the catalyst (example 2, the carrier 4B, the ratio in the charge THA:Al=60:40 wt. %, table 1) at different temperatures.
|Dilution With3H10:He volume.||Catalytic properties|
|V4H10h-1||V (C4H10+Not) h-1||T°||The degree of conversion %||Exit C4H6mol. %||Output (C4H6+C4H8) mol. %||The selectivity of C4H6+C4H8mol. %|
1. The catalyst for the process of dehydrogenation of hydrocarbons, containing in its composition chromium oxide, alkali metal supported on a carrier, wherein the carrier is a composite material including alumina and aluminum, while the share of pore size greater than 0.1 μm in the total volume of open pores of the carrier, 0.10-0,88 cm3/g media is 10.0 and 88.5%.
2. The preparation method of catalyst for the process of dehydrogenation of hydrocarbons containing chromium oxide, aluminum oxide and modifying additive comprising processing the carrier with a solution of chromium compounds and the solution of the modifying metal, preferably sodium or sodium and cerium, wherein the medium for use porous composite material containing aluminum oxide and aluminum obtained from the product of thermochemical Akti the purpose of hydrargillite, representing an amorphous compound Al2O3·mo2O, where is 0.25<n<2,0 added to a homogeneous mass in the amount of 1.0 to a 99.0 wt.%, and as an additional material used powdered aluminum metal, which is partially oxidized in the stages of hydrothermal treatment and annealing, while the share of pore size greater than 0.1 μm in the total volume of open pores of the carrier, 0.10-0,88 cm3/g media is 10.0 and 88.5%.
3. The process of dehydrogenation of hydrocarbons at the oxide-chromium-oxide-aluminum catalyst, characterized in that the use of the catalyst according to any one of claims 1 and 2.
FIELD: polymerization catalysts.
SUBSTANCE: invention relates to chromium oxide catalysts on inorganic carriers as components of double catalytic systems also including supported chromocene catalyst and used for synthesis of high-strength, crack-resisting low-pressure polyethylene. According to invention, preparation procedure comprises preliminarily drying silica (carrier), applying chromium and aluminum compounds thereon from solutions in organic solvent, removing solvent, drying resulting product and subsequent thermal-oxidative activation in dry air flow within temperature range between 450 and 750°C. Long-term polymerization activity of double catalytic system is achieved owing to using, as aluminum compound solution, solution of alkoxyalumoxane of general formula [Al(OR)n (OR')1-nO]m, where R denotes ethyl or isopropyl, R' group C6H9O2, n = 0.6 or 0.7, and m = 2-5, in water-free lower aliphatic alcohol and. as chromium compound solution, solution of dicyclopentadienylchromium in toluene, and preliminary drying of silica is carried out in fluidized bed in presence of ammonium hexafluorosilicate at constant temperature within the range 330-400°C. Invention is also characterized by that thermal-oxidative activation of catalytic product is followed by thermal-reductive activation thereof in flow of purified nitrogen mixed with dry carbon dioxide at constant temperature within the range 350-390°C.
EFFECT: prolonged long-term catalytic activity.
3 tbl, 22 ex
FIELD: powder metallurgy; method of impregnation by a metal(of VIII group) of a molecular sieve extrudate with cementing material with the help of ion exchange with an aqueous solution of metal salt of VIII group.
SUBSTANCE: the invention presents a method of impregnation by metal of VIII group of an extrudate of a molecular sieve with cementing material, in which the cementing material represents a refractory oxidic material with a low acidity, practically free of aluminum oxide, using: a) impregnation of porous volume of an extrudate of a molecular sieve with cementing material with an aqueous solution of nitrate of the corresponding metal of VIII group with pH from 3.5 up to 7, in which the molar ratio between cations of a metal of VIII group in a solution and a number of centers of the adsorption available in the extrudate, is equal to or exceeds 1; b) drying of the produced at the stage a) extrudate of the molecular sieve with the cementing material. The technical result is good distribution of the metal and a short period of drying.
EFFECT: the invention ensures good distribution of the metal and a short period of drying.
9 cl, 1 tbl, 4 ex
FIELD: alternate fuel manufacture catalysts.
SUBSTANCE: invention relates to generation of synthesis gas employed in large-scale chemical processes such as synthesis of ammonia, methanol, higher alcohols and aldehydes, in Fischer-Tropsch process, and the like, as reducing gas in ferrous and nonferrous metallurgy, metalworking, and on gas emission detoxification plants. Synthesis gas is obtained via catalytic conversion of mixture containing hydrocarbon or hydrocarbon mixture and oxygen-containing component. Catalyst is a complex composite containing mixed oxide, simple oxide, transition and/or precious element. Catalyst comprises metal-based carrier representing either layered ceramics-metal material containing nonporous or low-porosity oxide coating, ratio of thickness of metallic base to that of above-mentioned oxide coating ranging from 10:1 to 1:5, or ceramics-metal material containing nonporous or low-porosity oxide coating and high-porosity oxide layer, ratio of thickness of metallic base to that of nonporous or low-porosity oxide coating ranging from 10:1 to 1:5 and ratio of metallic base thickness to that of high-porosity oxide layer from 1:10 to 1:5. Catalyst is prepared by applying active components onto carrier followed by drying and calcination.
EFFECT: increased heat resistance and efficiency of catalyst at short contact thereof with reaction mixture.
13 cl, 2 tbl, 17 ex
FIELD: chemical industry, in particular two-component heterogeneous immobilized catalyst for ethylene polymerization.
SUBSTANCE: claimed catalyst includes alumina, mixture of transition metal complexes with nitrogen skeleton ligands (e.g., iron chloride bis-(imino)pyridil complex and nickel bromide bis-(imino)acetonaphthyl complex). According the first embodiment catalyst is prepared by application of homogeneous mixture of transition metal complexes onto substrate. iron chloride bis-(imino)pyridil complex and nickel bromide bis-(imino)acetonaphthyl complex (or vise versa) are alternately applied onto substrate. According the third embodiment catalyst is obtained by mixing of complexes individually applied onto substrate. Method for polyethylene producing by using catalyst of present invention also is disclosed.
EFFECT: catalyst for producing polyethylene with various molecular weights, including short chain branches, from single ethylene as starting material.
7 cl, 5 tbl, 27 ex
FIELD: alternative fuel production and catalysts.
SUBSTANCE: invention relates to (i) generation of synthesis gas useful in large-scale chemical processes via catalytic conversion of hydrocarbons in presence of oxygen-containing components and to (ii) catalysts used in this process. Catalyst represents composite including mixed oxide, simple oxide, transition element and/or precious element, carrier composed of alumina-based ceramic matrix, and a material consisting of coarse particles or aggregates of particles dispersed throughout the matrix. Catalyst has system of parallel and/or crossing channels. Catalyst preparation method and synthesis gas generation method utilizing indicated catalyst are as well described.
EFFECT: enabled preparation of cellular-structure catalyst with high specific surface area, which is effective at small contact times in reaction of selective catalytic oxidation of hydrocarbons.
6 cl, 2 tbl, 16 ex
FIELD: petrochemical process catalysts.
SUBSTANCE: preparation of catalyst comprises applying palladium compound onto silica cloth and heat treatment. Palladium compound is applied by circulation of toluene or aqueous palladium acetate solution through fixed carrier bed until palladium content achieved 0.01 to 0.5%. Palladium is introduced into cloth in dozed mode at velocity preferably between 0.1 and 5.9 mg Pd/h per 1 g catalyst. Heat treatment includes drying at temperature not higher than 150oC under nitrogen or in air and calcination in air or nitrogen-hydrogen mixture flow at temperature not higher than 450oC. Original silica cloth can be modified with 0.6 to 6.5% alumina. Palladium is uniformly distributed in silica cloth and has particle size preferably no larger than 15 Å. Invention can be used in treatment of industrial gas emissions and automobile exhaust to remove hydrocarbons.
EFFECT: deepened oxidation of hydrocarbons.
5 cl, 1 tbl, 4 ex
FIELD: petrochemical process catalysts.
SUBSTANCE: preparation of catalyst comprises two-step impregnation of preliminarily calcined carrier with first ammonium heptamolybdate solution and then, after intermediate heat treatment at 100-200°C, with cobalt and/or nickel nitrate solution followed by final heat treatment including drying at 100-200°C and calcination at 400-650°C. Catalyst contains 3.0-25.0% MoO3, 1.0-8.0% CoO and/or NiO on carrier: alumina, silica, or titanium oxide.
EFFECT: enhanced hydrodesulfurization and hydrogenation activities allowing involvement of feedstock with high contents of sulfur and unsaturated hydrocarbons, in particular in production of environmentally acceptable motor fuels.
3 cl, 4 tbl, 13 ex
FIELD: supported catalysts.
SUBSTANCE: invention claims a method for preparation of catalyst using precious or group VIII metal, which comprises treatment of carrier and impregnation thereof with salt of indicated metal performed at working pressure and temperature over a period of time equal to or longer than time corresponding most loss of catalyst metal. According to invention, treated carrier is first washed with steam condensate to entirely remove ions or particles of substances constituted reaction mixture, whereupon carrier is dried at 110-130oC to residual moisture no higher than 1%.
EFFECT: achieved additional chemical activation of catalyst, reduced loss of precious metal from surface of carrier, and considerably increased lifetime.
5 cl, 9 ex
FIELD: petrochemical synthesis catalysts.
SUBSTANCE: invention discloses a method for preparation of palladium catalyst comprising impregnation of alumina carrier with palladium chloride solution in presence of aqueous hydrochloric acid, treatment with reducing agent (hydrogen), washing with water, and drying, said carrier being preliminarily decoked exhausted catalyst containing alumina and group I and/or II, and/or VI, and/or VIII metals and subjected to washing with aqueous hydrochloric or nitric acid and then with water. Exhausted ethylene oxide production catalyst or methylphenylcarbinol dehydration catalysts can also be suitably used.
EFFECT: increased selectivity and activity of catalyst.
2 cl, 2 tbl, 21 ex
FIELD: petroleum processing catalysts.
SUBSTANCE: invention related to hydrofining of hydrocarbon mixtures with boiling range 35 to 250оС and containing no sulfur impurities provides catalytic composition containing β-zeolite, group VIII metal, group VI metal, and possibly one or more oxides as carrier. Catalyst is prepared either by impregnation of β-zeolite, simultaneously or consecutively, with groups VIII and VI metal salt solutions, or by mixing, or by using sol-gel technology.
EFFECT: increased isomerization activity of catalytic system at high degree of hydrocarbon conversion performed in a single stage.
40 cl, 2 tbl, 19 ex