Process of selective hydrogenation of acetylene hydrocarbons in olefin-rich gas mixtures

FIELD: petrochemical processes.

SUBSTANCE: invention relates to hydrogenation of acetylene hydrocarbons in olefin-rich gas mixtures on heterogeneous catalysts. Hydrogen and olefin containing stream with admixtures of acetylene hydrocarbons is passed through catalyst bed, which is composed of (a) geometrically structured system including fibers of high-silica fibrous carrier characterized by presence in IR specter of hydroxyl group absorption band having wavelength υ=3620-3650 cm-1 and half-width 65-75 cm-1, having specific surface SAr=0.5-30 m2/g as measured by BET method from thermal desorption of argon, surface area SNa=5-150 m2/g as measured by alkali titration method, at ratio SNa/SAr=5-50; and (b) active element. Active element is made in the form of charged either metallic or bimetallic clusters characterized in diffuse-reflection UV-Vis specter by specific bands in region 34000-42000 cm-1 and ratio of (i) integral intensiveness of the band related to charged either metallic or bimetallic clusters to (ii) integral intensiveness of the band related, respectively, either to metallic or bimetallic particles is at least 1.0.

EFFECT: increased activity and selectivity of process at high ethylene/acetylene ratios.

5 cl, 1 dwg, 3 tbl

 

The invention relates to the field of chemistry, namely the selective hydrogenation of acetylenic hydrocarbons in the olefin in gas mixtures rich in olefins, heterogeneous catalysts.

Used in industry olefins such as ethylene and propylene, usually contain small amounts of acetylenic hydrocarbons such as acetylene, methylacetylene, the presence of which is usually undesirable in the further use of olefins. The main task of the effective management of the process of selective hydrogenation of mixtures rich in olefins is the most complete removal of acetylene impurities without losing the main product - olefins due to their undesirable hydrogenation to the saturated hydrocarbon - paraffins.

Known methods for the selective hydrogenation of acetylenic compounds in the ethylene-acetylene gas mixtures, which include passing the gaseous mixture through the catalyst bed, which is usually used palladium deposited on oxide carriers in the form of cylindrical pellets, beads, rings. As well known process for the selective hydrogenation of acetylenic compounds in the presence of excess olefin such as ethylene and propylene (U.S. Patent No. 3113980, "Catalysts and process for the selective hydrogenation of acetylenes", IPC B 01 J 23/44, C 07 C 05/08, priority from 18.02.1960, publ. 10.12.1963). The method includes passing g the gas mixture of olefins, containing about 2% vol. acetylene hydrocarbon through the catalyst bed. The catalyst comprises 0.001-5.0 wt.% Pd, preferably 0.01-0.4 wt.% Pd supported on alumina having a pore size 200-1400 And, preferably 200-700 And the value of the specific surface 5-65 m2/g, preferably 10-30 m2/g, made in the form of granules of spherical or cylindrical shape size ˜3 mm Temperature process 60-150°C, the volumetric rate of gas 1-20000 h-1.

The disadvantage of this method is the low selectivity to ethylene due to the fact that in the conditions of the process hereroense not only acetylene, but a significant portion of the ethylene hereroense in ethane.

One method of increasing the selectivity of the process is the use of Pd catalysts promoted with different elements. Thus, the known method of selective hydrogenation of small amounts of acetylene in the gas mixture with an excess of ethylene using a catalyst comprising a palladium 0.001-1.0 wt.% preferably 0.005-0.25 wt.%, promoted by zinc in the amount of 0.0005-2.5 wt.% Zn, preferably 0.001-1.0 wt.% Zn, and deposited on granular silica with a specific surface area 25-400 m2/g, grain size 3-6 mm (U.S. Patent 3821323 "Selective hydrogenation of minor amounts of acetylene in a gas mixture containing major amounts of ethylene", IPC C 07 C 11/00, priority is from 14.11.1972, publ. 28.06.1974).

Also known process for the selective hydrogenation of acetylene hydrocarbons containing 2 or 3 carbon atoms into the corresponding olefins in the presence of catalysts in the form of spherical or cylindrical granules containing a carrier of aluminum oxide with a specific surface area 5-60 m2/g, the active element palladium in the amount of 0.01-0.5 wt.% and as promoters of at least one element of group 1B, preferably silver in an amount of from 0.001 to 0.02% and at least one alkaline or alkaline-earth metal in a weight ratio of the metal of group 1B to a palladium 0.05/1-0.25/1, and more than 80% of the silver is located in a thin surface layer of the device (U.S. Patent 5648576 "Catalytic hydrogenation process and catalyst for use in the process". IPC B 01 J 23/44, C 07 C 05/09, priority from 06.06.95, publ. 15.07.97).

A disadvantage of known methods using promoted palladium catalysts is the lack of stability of the process over time due to gradual poisoning of the catalysts deposited on the surface of products of oligomerization of hydrocarbons. In addition, the catalysts of the traditional geometric shapes in the form of a relatively large spheres or cylindrical pellets do not provide good heat and mass transfer in the catalytic layer. And poor mass transfer and, consequently, the diffusion hindered the I in the course of adsorption-desorption processes contribute to complete hydrogenation to ethane, not only undesirable impurities acetylene, and ethylene, i.e. lead to the loss of the main product. Strong heating of the layer due to poor heat sink reduces the selectivity and promotes the formation of oligomers, leading to deactivation of the catalyst. With decreasing size of the granules in bulk layers of granular catalysts with increasing flow rate of the supply of the mixture increases the hydraulic resistance that limits the productivity of industrial reactors.

Therefore, to improve the efficiency of the process along with the selection of the optimal chemical composition of the essential selection of optimal textural characteristics of the used catalyst: the values of specific surface area, pore size, and the choice of the optimal geometric shapes and grain sizes of the catalysts.

A known process for the selective hydrogenation of acetylene to remove it from the gas mixture containing ethylene, ethane, methane and 0.3-2.0 wt.% acetylene, using a catalyst comprising palladium in the amount of 0.005-0.1 wt.%, and promoting the elements Cu, Ag, Ni, Fe in an amount of 0.005-0.25 wt.%, put on α-Al2About3made in the form of multi-channel units with a specific surface area not less than 50 m2/g and macroporous structure in which no man is e 33% then should be larger than 500 a (Patent of great Britain No. 1596959 "Selective hydrogenation of C2 minus fractions", IPC B 01 J 23/44, priority from 30.05.78, publ. 03.09.81). The use of multi-channel modular media reduces diffusion difficulties for mass and heat transfer.

The disadvantage of the process to block the catalyst is insufficient activity.

To improve the efficiency of processes of selective hydrogenation are encouraged to use catalysts optimal geometric shape in the form of membranes (C.K.Lambert, R.D.Gonzalez. "Activity and selectivity values of Pd/γ-Al2O3catalytic membrane in the partial hydrogenation reactions of acetylene and 1,3-butadiene". // Catalysis Letters, V.57, 1999, P.1-7). There is a method of hydrogenation of hydrocarbon membranes, made of metal foil Pd, or alloys of Pd/Ni, Pd/Ru, Pd/Ag (U.S. Patent 4132668. "Method of preparing a hydrogen-permeable membrane catalyst on a base of palladium or its alloys for the hydrogenation of unsaturated organic compounds", IPC B 01 J 31/28; B 01 J 31/06; C 07 C 5/16, priority from 06.04.1977, publ. 02.01.1979).

The lack of selective hydrogenation of such membrane catalysts is more expensive process due to the large consumption of precious metals and the reduction of strength of the membranes in terms of process under the action of hydrogen present in the reaction mixture.

More efficient and simple method is selective hydrogenation using a geometrically structured catalytic systems on the basis of available and simple to manufacture carriers from silicate glass the fibers.

Closest to the proposed method is selective hydrogenation of acetylene or diene hydrocarbons present in the mixture with monoolefins, using catalysts based on glass fiber media (Patent RF №2164814, "Catalyst for selective hydrogenation of acetylene and/or diene hydrocarbons", ITUC B 01 J 23/40, B 01 J 35/06, C 07 C 7/167, B 01 J 23/40, 01 J 103:38, 01 J 103:50, 01 J 103:52, priority dated 05.10.1999, publ. 10.04.2001). In the known method for increasing the resistance of the catalyst to poisoning by sulfur compounds and products of oligomerization using a catalyst comprising at least one active component selected from the metals of group VIII in the amount of 0.001-1.0 wt.%, on the media, which is used fiberglass silicate material with a silicon dioxide content 50-99 .9 wt.% and a specific surface area of 0.1-200 m2/, Fiberglass media is a woven or non-woven structure with a diameter of elementary fibers of 1-20 μm. The catalyst contains a promoter in the amount of 0.01-2.0 wt.%, selected from the group of alkali or alkaline earth metal, tin, molybdenum, tungsten. The catalyst has high thermal stability, are resistant to the action of serosoderjaschei compounds, moisture and has a high activity and selectivity in the temperature range 40-130°C, flow rate CAS -1when the test gas mixture with a relatively low ratio of ethylene/acetylene ˜1 (1.0% vol. ethylene, 1.0 vol.% acetylene, 2.0 vol.% hydrogen, 96.0% vol. argon,

The disadvantage of this method is that the catalyst is not sufficiently active (conversion of acetylene less than 80%) and selective (hydrogenation of ethylene to ethane over 3%) with an excess of ethylene, i.e. at high ratios of ethylene/acetylene characteristic of industrial feed mixtures for which the ratio of ethylene/acetylene is typically 50-200.

The objective of the invention was to develop a method of hydrogenation of acetylenic compounds in gas mixtures rich in olefins, providing high conversion and selectivity in the conversion of acetylene hydrocarbons into olefins, without loss of olefins.

This physico-chemical and geometrical properties of the catalyst should provide high activity and selectivity, as well as satisfactory aerodynamic properties with low hydraulic resistance, good mass and heat transfer.

The problem is solved in that in the method for selective hydrogenation of acetylenic compounds in gas mixtures rich in olefins comprising passing through the catalyst bed of the stream of hydrogen and olefins containing impurities of acetylene hydrocarbons, as the catalysis of the Torah uses geometrically structured system, includes microfiber vysokokremnezemnstogo fibrous media, which is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3620-3650 cm-1and the width of 65-75 cm-1has a specific surface area measured by the BET method by thermal desorption of argon, SAr=0.5 to 30 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa5-150 m2/g at a ratio of SNa/SAr5-50, and at least one active element, wherein the active element is made with the possibility of the formation of charged either metallic or bimetallic clusters, characterized in UV-visible spectrum of the diffuse reflection of specific bands in the region 34000-42000 cm-1and the ratio of the integrated intensity of the bands related to charged either metallic or bimetallic clusters, to the integrated intensity of the band related, respectively, or to the metal or bimetallic particles, not less than 1.0. Metal clusters are formed from atoms or platinum, or palladium, or rhodium, or iridium, or silver, or Nickel, or copper, or tin, or gold. Bimetallic clusters formed from compound atoms or palladium, or platinum atoms, or silver, or cob is the LTE, either Nickel or copper, or tin, or gold. This microfiber vysokokremnezemnstogo fibrous media contain 50-98,8% SiO2and at least one element selected from the group comprising the metals aluminum, iron, molybdenum, titanium, zirconium, chromium, manganese, alkaline, alkaline earth and rare earth elements.

The technical effect of the proposed method lies in the fact that the hydrogenation of acetylenic hydrocarbons in the feed mixtures with an excess of olefin is held with high activity and selectivity, i.e. at high conversion of acetylenes to olefins, with no or minimal conversion of olefins to paraffins. This results in efficient purification of gas mixtures from acetylenes without loss of olefins.

The method is illustrated in the drawing, which shows UV-visible spectra of diffuse reflection, and tables 1 and 2, which shows the degree of conversion of acetylenic compounds: acetylene and methylacetylene and changes in the concentration of olefins: ethylene and propylene in the selective hydrogenation of acetylene-ethylene and methylacetylene-propylene mixtures.

Proposed in the invention vysokoglinozemistyj media, comprising 50-98 .8 wt.% silicon dioxide, characterized by the following physicochemical properties:

in the infrared spectrum has absorption band of hydroxyl gr is PP with wave number 3620-3650 cm -1and the width of 65-75 cm-1.

the carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=0.5 to 30 m2/g and the magnitude of the surface, measured by the method of alkaline titration, SNa5-150 m2/g, the ratio of SNa/SAr5-50.

The totality of the claimed features demonstrates the specific structure of the fibrous medium and the possibility of forming on the active state of the applied component. For example, in the infrared spectrum absorption bands of Oh groups in the region of wave numbers 3620-3650 cm-1and the small width of this band indicates the presence in the medium of a significant number of Oh groups, not localized on the outer surface, as for traditional silica, and in small and fairly homogeneous in terms of the geometry of the cavities. Similar bands described in the literature for silicate materials containing Oh groups in the volume of globules or in very small pores (Iler R. the Chemistry of silica. M.: Mir, 1982. Vol.2. S. Chukin GD, Abramova A.I., Seliverstova IV // Kinetics and catalysis. 1994. T.35. S). In addition, the present invention claimed large differences in the values of specific surface area measured by the BET method by physical adsorption of argon SAr=0.5 to 30 m2/g and the method of Sears by chemisorption of charged particles - cations h is Tria S Na5-150 m2/g (G.W.Sears // Anal. Chem. - 1956. - V.28. - R. Railer. The chemistry of silica. - M.: Mir, 1982. - Vol.2. - S). A significant excess of the surface, measured by chemisorption of sodium SNa, the values of specific surface area determined by the BET method by physical adsorption of argon, SNa/SAr5-50 shows the presence of fibrous media of active sites available for chemisorption of charged particles - cations Na+(diameter ˜1.4 (a) and partially available for the physical adsorption of molecules of Ar.

The presence of these symptoms may lead to the formation of the highly active state of the applied active element in the form of charged metal clusters Meδ+, characterized in UV-visible spectrum of the diffuse reflection of a specific band 38000-42000 cm-1. Moreover, the proportion of charged clusters should be large enough: the ratio of the integral intensity of the band with a maximum at 38000-42000 cm-1related to charged metal clusters, to the integrated intensity of the band with a maximum at 48000 cm-1related to metal particles IU0must be at least 1 , Icluster/Imeth≥1.0.

Microfiber vysokokremnezemnstogo fibrous media contain 50-98 .8 wt.% SiO2and at least one element selected from the group comprising metals aluminum is, iron, molybdenum, titanium, zirconium, chromium, manganese, alkaline, alkaline earth and rare earth elements.

The presence of fibrous media claimed promoters alters the composition and structure of the inner circle of the applied active elements and, accordingly, may further affect their properties: size and electronic state (amount of charge) of the cluster.

Microfiber vysokokremnezemnstogo media with a diameter of 5-20 μm should be structured in the form of a woven or extruded material such as wool felt, or threads with a diameter of 0.5-5.0 mm, or in the tissues of these threads weave type : sateen, canvas, mesh with a cell size of 0.5-5.0 mm, Such a geometric structure ensures the absence of diffusion problems in heat and mass transfer, and this can give an additional contribution to the increase in activity and selectivity. In addition, the geometrical structuring improves the technological parameters of reaction: increases the permeability of the catalyst layer, reduces its hydraulic resistance, which is important for achieving a high volumetric flow rate, and, consequently, high performance industrial process.

In combination with the above, the active state of the input of the active element, it may cause characteristic declare what about the method of selective hydrogenation, the high activity and selectivity in the hydrogenation of acetylenic compounds with an excess of olefin.

Applied catalysts used in the invention, can be prepared, for example, by impregnation of a high glass fiber media with the claimed properties of aqueous solutions of salts of active elements with the subsequent removal of the impregnating solution and the heat treatment of the catalyst in air and hydrogen.

Included in the media modifying elements selected from the group comprising the metals aluminum, iron, molybdenum, titanium, zirconium, chromium, manganese, alkaline, alkaline earth and rare earth elements are either at the stage of preparation of media, or just before the introduction of the active element.

Methods of measurement of catalytic activity in the reaction of selective hydrogenation of mixtures of ethylene/acetylene or methylacetylene/propylene. Tests are conducted in flow-through installation using tubular metal reactor with an inner diameter of 25 mm at atmospheric pressure and temperatures up to 200°C. the Catalyst loaded into the reactor in the form of several circles with a diameter of 25 mm, perpendicular to the gas flow. The total sample ranged from 1 to 2, Before catalytic testing, the catalyst for 1 hour soak in flux is e hydrogen 2 l/h at a temperature of 200° C. Then the catalyst was cooled in a stream of hydrogen to a temperature of 80°and in the reactor serves the reaction mixture, containing 1% acetylene hydrocarbon, 1.2-1.6% hydrogen and 97.8-97.4% of the olefin is ethylene or propylene. Analysis of the composition of the initial reaction mixture and the products is carried out chromatographically using chromatograph Crystal-2000 Meters

In the drawing 1 shows the UV spectra for the four typical Pd-containing catalysts described in examples 1-4, Issledovanie the presence of clusters was based on UV-visible spectra of diffuse reflection shot spectrometer Shimadzu 4501, equipped console ISR-250. In table Pd-containing catalysts were progulivali in air at 350°was restored in hydrogen at 200°C for 1 hour and cooled in a stream of hydrogen to room temperature. Samples densely filled in a quartz cuvette and the cuvette was placed in a console BEFORE. Estimate of the ratio of integrated intensity was performed after decomposition of the observed spectrum at the individual Gaussian components. Intensity was defined as the area under the Gaussian curve describing the contours of the selected absorption bands 38000±4000 cm-1and 48000±4000 cm-1.

Presented in the drawing 1F-type spectra of diffuse reflection can be seen that in the inventive catalysts palladium can have Itsa in three States:

Pd2+- in the form of ions of bivalent palladium (strip 22000-26000 cm-1),

Pd0- in the form of metal particles (lanes 48000±4000 cm-1),

Pdδ+0<δ<2 - in the form of charged metal clusters (strip 38000±4000 cm-1).

For optimal samples in examples 3 and 4 in the spectrum of UV-a view of the most intense band is about 50,000 cm-1. This suggests that a significant proportion of palladium is present in the form of metal particles on the outer surface of optical fibers. Simultaneously recorded bands in the range of 22000-26000 cm-1proving the presence of divalent ions of palladium, and the band relating to the charged clusters Pdδ+0<δ<2. But the share of small clusters: Icluster/Imeth=0.15 and 0.4 for samples No. 3 and 4, respectively.

Optimal samples No. 1 and 2 of examples 1 and 2 are characterized by a band with a maximum in the area of 38000 cm-1characteristic of charged metal clusters, whereas the palladium ions are practically absent, and the share of small metal particles: the ratio of Icluster/Imeth=1 and 3.

This is due to the use of a catalyst comprising Pd deposited on vysokoglinozemistyj fibrous media with the claimed set of physico-chemical and geometrical properties, which leads to the formation of an asset is the th element Pd in the form of charged metal clusters Pd δ+.

The inventive method is illustrated by the following examples.

Example 1.

Produce selective hydrogenation of the ethylene-acetylene mixture, which gas mixture containing 1% acetylene, 1.6% hydrogen, 97.4% vol. ethylene ratio (ethylene/acetylene = 97.7) passed at 100°and flow rate of 5000 h-1through the layer of geometrically structured catalytic systems.

Vysokoglinozemistyj fibrous media system is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3630 cm-1and a width of 70 cm-1. The carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=1.2 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa=26 m2/g and the ratio of SNa/SAr=21.7. The catalytic system contains 0.02 wt.% Pd, most of the palladium is present in the form of charged clusters Pdδ+0<δ<2, characterized in UV-visible spectrum of the diffuse reflection band with a maximum 38000 cm-1(drawing, curve 1). The ratio of the integrated intensity of the band with a maximum at 38000 cm-1relating to the charged clusters of palladium to the integrated intensity of the band with the maximum at 48000 cm-1related to use the m particles of palladium, is 1 (Icluster/Imeth=1.0).

The medium of sample No. 1 catalytic system is a microfiber vysokokremnezemnstogo media, including 95.8 wt.% SiO2and 1.55 wt.% Al, 0.04 wt.% Fe, 0.08 wt.% Na, 0.5 wt.% Sa, 0.3 wt.% Mg. The media has the structure of a fabric mesh netting, in which the fibers with a diameter of 10 μm spun into filaments with a diameter of 1.5 mm which form a grid with square cells 3.0×3.0 mm and hole size 1.5×1.5 mm

Table 1 shows that sample No. 1 of the catalyst of example 1 showed the highest conversion rate of acetylene 88.2% and an increase in the concentration of ethylene in the reaction products at 0.72%. No loss of ethylene testify to the high selectivity of the hydrogenation of acetylene to ethylene, without subsequent hydrogenation of ethylene to ethane.

Example 2

Produce selective hydrogenation of the ethylene-acetylene mixture, which gas mixture containing 1% acetylene, 1.6% hydrogen, about 97.4 % of ethylene ratio (ethylene/acetylene = 97.7) is passed through a layer of geometrically structured catalytic systems at 100°and flow rate of 5000 h-1.

Fibrous media of sample No. 2 geometrically structured catalytic system is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3620 cm-1poluchenii 65 cm -1. The carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=0.8 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa=35 m2/g and the ratio of SNa/SAr=44. The catalyst contains 0.02 wt.% Pd, most of the palladium is present in the form of charged clusters Pdδ+0<δ<2, characterized in UV-visible spectrum of the diffuse reflection band with a maximum 42000 cm-1(drawing, curve 2). The ratio of the integrated intensity of the band with a maximum at 42000 cm-1relating to the charged clusters of palladium (Icluster)to the integrated intensity of the bands in the interval 48000 cm-1related to metallic palladium particles (Imeth), is 3 (Icluster/Imeth=3).

Sample No. 2 geometrically structured catalytic system contains microfiber vysokokremnezemnstogo media, including 96.2 wt.% SiO2and 0.008 wt.% Na, 0.09 wt.% Al, and rare earth elements: 0.31 wt.% La, 0.26 wt.% Y, 0.91 wt.% Behold, 0.39 wt.% Pr, 0.17 wt.% Nd, 0.17 wt.% Sm, 0.69 wt.% Er. The media has the structure of a fabric mesh netting, in which the fibers with a diameter of 5 micron spun into filaments with a diameter of 1.0 mm of which is woven grid with square cells of 2.5×2.5 mm hole size is 1.5×1,5 mm

Table 1 show the but the catalyst according to example 2 showed the highest conversion rate of acetylene was 99.4% and the increase in the concentration of ethylene in the reaction products at 0.74%. No loss of ethylene testify to the high selectivity of the hydrogenation of acetylene to ethylene, without subsequent hydrogenation of ethylene to ethane.

Example 3

Similar to example 1. The difference is that the media is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3610 cm-1and a width of 80 cm-1. The carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=1.2 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa=2.4 m2/g and the ratio of SNa/SAr=2. The catalyst contains 0.2 wt.% Pd, and a significant part of the palladium is present in the form of metallic palladium (drawing, curve 3). The ratio of the integrated intensity of the band with a maximum at 38000 cm-1relating to the charged clusters of palladium to the integrated intensity of the bands related to metallic palladium particles is 0.15 (Icluster/Imeth=0.15).

Catalyst carrier No. 3 contains microfiber vysokokremnezemnstogo media, including 97.2 wt.% SiO2and 0.12 wt.% Na, 1.4 wt.% Al. The media has a fabric structure plain plait is to be placed, in which fiber with a diameter of 20 μm spun into filaments with a diameter of 0.5 mm, of which the woven fabric of plain weave.

Table 1 shows that the catalyst according to example 3 showed low conversion of acetylene 25% and the decrease of the concentration of ethylene in the reaction products at 0.04%, which indicate undesirable hydrogenation parts of ethylene to ethane.

Example 4.

Similar to example 1, characterized in that the medium is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3670 cm-1and a width of 60 cm-1the size of the specific surface by argon SAr=0.5 m2/g, the size of the surface, measured by the method of alkaline titration, SNa=5 m2/g and the ratio of SNa/SAr=10. The Pd content is 0.02 wt.%, the ratio of Icluster/Imeth=0.4. No loss of ethylene in the reaction products indicates higher than in example 3, the selectivity. The conversion of acetylene increases in comparison with example 3, where Icluster/Imeth=0.15 but less than in examples 1 and 2 where the Icluster/Imethis 1 and 3, respectively.

Example 5.

Similar to example 4. The difference is that the carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=0.2 m2/g, the magnitude of the surface, u is nnow using alkali titration, SNa=140 m2/g and the ratio of SNa/SAr=700. The catalyst contains 1.2 wt.% Pd. The ratio of Icluster/Imeth=0.11.

Table 1 shows that the catalyst according to example 5 showed low conversion of acetylene and low selectivity for ethylene, as there is a decrease in the concentration of ethylene in the reaction products at 0.05%.

Example 6

Similar to example 1. Characterized in that the fibrous carrier includes additional promoters Cr 0.02 wt.%, Mo 0.05 wt.%, Ti 0.05 wt.%, Mn 0.005 wt.%. The catalyst contains 0.005 wt.% Pd. The ratio of Icluster/Imeth=2.2.

The conversion of acetylene is 90%, the concentration of ethylene in the products is increased by 0.71%.

Example 7. Similar to example 1, characterized in that the bimetallic clusters catalytic system containing 0.03 wt.% Pd and 0.09 wt.% Au. The ratio of Icluster/Imeth=1.2. The conversion of acetylene is 98%, the concentration of ethylene in the products increases by 0.73%.

Example 8.

Similar to example 2, characterized in that the bimetallic clusters catalytic system containing 0.02 wt.% Pd and 0.03 wt.% Pt. The ratio of Icluster/Imethdecreased to 0.2. This has led to reduced conversion of acetylene to 30.9% while maintaining high selectivity, as evidenced by the increase in the concentration of ethylene in the products at 0.24%.

Example 9.

Similar is the iMER 2, but the sample of catalyst No. 2 was tested in the reaction of selective hydrogenation of a mixture of propylene with methylacetylene. As can be seen from table 2, the catalyst showed high conversion methylacetylene 93%, without losing the main product of propylene.

Example 10

Similar to example 1. The difference is that the media is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3610 cm-1and a width of 80 cm-1. The carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=1.2 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa=2.4 m2/g and the ratio of SNa/SAr=2. The catalyst contains 0.03 wt.% Pt, and a significant part of the metal present in the form of clusters and is characterized by a maximum in the UV-visible spectra at 36000 cm-1related to charged platinum clusters. The ratio of the integral intensity of the band relating to the charged clusters, to the intensity of the bands due to metal particles (Imeth)is 2 (Imeth=0,95).

Catalyst carrier No. 10 contains microfiber vysokokremnezemnstogo media, including 97.2 wt.% SiO2and 0.12 wt.% Na, 1.4 wt.% Al. The media has a fabric structure plain weave, in which the fibers with diameter is 20 μm spun into filaments with a diameter of 0.5 mm, of which woven fabric of plain weave.

Table 3 shows that the catalyst according to example 10 showed the magnitude of the conversion of acetylene to 96.5%. The decrease of the concentration of ethylene is not observed.

Example 11

Similar to example 10. The difference is that the carrier has a specific surface area measured by the BET method by thermal desorption of argon, SAr=0.5 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa=5 m2/g and the ratio of SNa/SAr=10. The catalyst contains 0.03 wt.% Pt. The ratio of the integrated intensity of the band with a maximum at 38000 cm-1related to charged platinum clusters, to the integrated intensity of the bands related to the metal particles of platinum, is 2.5 (Imeth=0.7).

Sample No. 11 geometrically structured catalytic system contains microfiber vysokokremnezemnstogo media, including 96.2 wt.% SiO2and 0.008 wt.% Na, 0.09 wt.% Al, and rare earth elements: 0.31 wt.% La, 0.26 wt.% Y, 0.91 wt.% Behold, 0.39 wt.% Pr, 0.17 wt.% Nd, 0.17 wt.% Sm, 0.69 wt.% Er. The media has the structure of a fabric mesh netting, in which the fibers with a diameter of 5 micron spun into filaments with a diameter of 1.0 mm which form a grid with square cells of 2.5×2.5 mm hole size is 1.5×1,5 mm

Table 3 shows that the catalyst according to example 11 show the l and a high value of conversion of acetylene 99,3%. The decrease of the concentration of ethylene is not observed. In General, the catalysts containing instead of the palladium clusters clusters of platinum, they have less activity in the hydrogenation, however, the selectivity of the hydrogenation in the formation of ethylene is maintained at a high level from 70 to 80%.

1. Process for the selective hydrogenation of acetylenic compounds in gas mixtures rich in olefins comprising passing through the catalyst bed of the stream of hydrogen and olefins containing impurities of acetylenic compounds, as a catalyst used geometrically structured system that includes microfiber vysokokremnezemnstogo fibrous media, which is characterized by the presence in the infrared spectrum absorption band of hydroxyl groups with wave number ν=3620-3650 cm-1and the width of 65-75 cm-1has a specific surface area measured by the BET method by thermal desorption of argon, SAr=0.5 to 30 m2/g, the magnitude of the surface, measured by the method of alkaline titration, SNa5-150 m2/g at a ratio of SNa/SAr=5-50, and the active element, wherein the active element is made in the form of charged either metallic or bimetallic clusters characterizing the I in the UV-visible spectrum of the diffuse reflection of specific bands in the region 34000-42000 cm -1and the ratio of integral intensity of the band relating to the charged either metallic or bimetallic clusters, to the integrated intensity of the band related, respectively, or to the metal or bimetallic particles, not less than 1.0.

2. The method according to claim 1, characterized in that the metal clusters are formed from atoms or platinum, or palladium, or rhodium, or iridium, or silver, or Nickel, or copper, or tin, or gold,

3. The method according to claim 1, characterized in that the bimetallic clusters formed from compound atoms or palladium, or platinum atoms, or silver, or cobalt, or Nickel, or copper, or tin, or gold.

4. The method according to claim 1, wherein the microfiber vysokokremnezemnstogo media contain 50-98,8% SiO2and at least one element selected from the group comprising the metals aluminum, iron, molybdenum, titanium, zirconium, chromium, manganese, alkaline, alkaline earth and rare earth elements.

5. The method according to claim 1, wherein the microfiber vysokokremnezemnstogo media with a diameter of 5-20 μm should be structured in the form of a woven or extruded material such as wool felt, or threads with a diameter of 0.5 to 5.0 mm, or in the tissues of these threads weave type : sateen, canvas, mesh with a cell size of 0.5-5.0 m is.



 

Same patents:

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention relates to technology for isolation and purification of butadiene prepared by thermal cracking of hydrocarbons followed by removing heavy by-side products from crude butadiene flow after the selective hydrogenation of undesirable impurities. The flow outgoing from the reaction zone of the selective hydrogenation is fed into evaporator with fraction zone for extraction of butadiene wherein this zone is sprayed with the raffinate flow from the zone of butadiene extraction. From the evaporator the vapor phase containing butadiene with reduced concentration of by-side products is removed and fed to the stage for isolating the concentrated liquid phase comprising heavy by-side products of the reaction. Butadiene-containing vapor phase is recovered to the zone for extraction of butadiene. The fraction zone comprises from 3 to 7 theoretical plates. The temperature in evaporator is maintained in the range from 27°C to 93°C under the pressure value from 375 to 790 kPa. Invention provides the improved technology in preparing the purified butadiene.

EFFECT: improved method for treatment.

5 cl

FIELD: petroleum chemistry, chemical technology.

SUBSTANCE: method involves contacting the parent flow with a catalyst of selective hydrogenation. Catalyst comprising polymeric compounds is contacted with solvent for polymers and hydrogen. Flow containing solvent for polymers and dissolved polymeric compounds are separated for a flow containing a solvent for polymers with the decreased concentration of polymeric compounds and a flow enriched with polymeric compounds. At least part of the first flow is recirculated and the second flow is removed. Flow of diolefin compounds with the decreased concentration of acetylene compounds is prepared. Invention provides increase of working cycle of the process and decrease of added fresh solvent.

EFFECT: improved method for treatment and preparing.

7 cl, 1 dwg, 2 ex

FIELD: petroleum chemistry, chemical technology.

SUBSTANCE: method involves preparing flow of C2- and C3-olefin raw containing acetylenes, diolefins and some low-molecular light gases taken among the group comprising hydrogen, carbon monoxide and methane. Method involves separation of light gases and C2- and C3-acetylene and diolefin impurities are hydrogenated in a single flow of raw under a catalyst layer by addition of hydrogen to the raw flow to obtain the olefin raw flow containing significantly lower content of C2- and C3-acetylene and diolefin impurities and without significant reducing the amount of C2- and C3-olefins in the raw flow followed by separation of C2- and C3-olefins. Method provides reducing in formation of oligomers, enhanced selectivity in the hydrogenation process.

EFFECT: improved method for hydrogenation.

15 cl, 3 dwg, 2 ex

The invention relates to the simultaneous selective hydrogenation of vinylacetylene, ETHYLACETYLENE and 1,2-butadiene in the flow of C4rich olefin

The invention relates to the production of monomers for synthetic rubber, namely the process of purification of isoprene from acetylene hydrocarbons by hydrogenation

FIELD: catalysts of selective hydrogenation of alkynes of C4 fractions.

SUBSTANCE: proposed catalyst contains 1-30 mass-% of copper used as first active component, 0.001-5 mass-% of palladium used as second active component, at least 0.001-6 mass-% of one metal selected from Al, Pt, Pb, Mn, Co, Ni, Cr, Bi, Zr and Mo as co-catalyst; the remainder being one carrier selected from aluminum oxide, silicon dioxide and titanium oxide. Method of production of catalyst includes impregnation of carrier calcined preliminarily with solutions of active components depending on their content in catalyst. Alkynes are removed from C4 fractions enriched with alkynes by means of selective hydrogenation with the use of said catalyst.

EFFECT: enhanced selectivity and stability of catalyst.

31 cl, 2 tbl, 13 ex

The invention relates to the field of chemical technology

The invention relates to catalytic systems for the selective hydrogenation of acetylenic hydrocarbons in the ethane-ethylene fraction of pyrolysis oil

The invention relates to the selective hydrogenation of diolefins and acetylene compounds in the stream enriched in olefins

FIELD: catalyst preparation methods.

SUBSTANCE: invention, in particular, relates to catalyst based on synthetic mesoporous crystalline materials and provides hydrocarbon conversion catalyst composed of: group VIII metal/SO42-/ZrO2-EOx, where E represents element of the group III or IV of Mendeleev's periodic table, x = 1.5 or 2, content of SO42- is 0.1 to 10% by weight, ZrO2/EOx molar ratio is 1:(0.1-1.0), which has porous crystalline structure with specific surface 300-800 m2/g and summary pore volume 0.3-0.8 cm3/g. Preparation method comprises precipitation of zirconium compounds, in particular zirconium hydroxide or zirconyl, under hydrothermal conditions in presence of surfactant to form mesoporous phase, which is stabilized with stabilizing agents: group III and IV elements. When stabilization is achieved, if necessary, acidity is adjusted and group VIII metal is added.

EFFECT: increased specific surface area and heat resistance at simplified technology.

9 cl, 2 dwg, 2 tbl, 6 ex

FIELD: petrochemical processes and catalysts.

SUBSTANCE: invention provides catalyst composed of heteropolyacid: phosphorotungstic acid and/or phosphoromolybdenic acid, at least one precious metal deposited on essentially inert inorganic amorphous or crystalline carrier selected from group including titanium dioxide, zirconium dioxide, aluminum oxide, and silicon carbide, which catalyst retains characteristic structure of heteropolyacid confirmed by oscillation frequencies of the order 985 and 1008 cm-1 recorded with the aid of laser combination scattering spectroscopy and which has specific surface area larger than 15 m2/g, from which surface area in pores 15 Å in diameter is excluded. Method of converting hydrocarbon feedstock containing C4-C24-paraffins in presence of above-defined catalyst is likewise described.

EFFECT: increased catalyst selectivity and enhanced hydrocarbon feedstock conversion.

5 cl, 7 tbl, 7 ex

FIELD: petrochemical process catalysts.

SUBSTANCE: invention relates to catalytic methods of isomerizing n-paraffins and provides catalyst constituted by catalytic complex of general formula MexOy*aAn-*bCnXmH2n+2-m, where Me represents group III and IV metal, x=1-2, y=2-3, An- oxygen-containing acid anion, a=0.01-0.2, b=0.01-0.1; CnXmH2n+2-m is polyhalogenated hydrocarbon wherein X is halogen selected from a series including F, Cl, Br, I, or any combination thereof, n=1-10, m=1-22, dispersed on porous carrier with average pore radius at least 500 nm and containing hydrogenation component. Method of preparing this catalyst is also disclosed wherein above-indicated catalytic complex is synthesized from polyhalogenated hydrocarbon CnXmH2n+2-m wherein X, n, and m are defined above, group III and IV metal oxide, and oxygen-containing acid anion, and dispersed on porous carrier with average pore radius at least 500 nm, hydrogenation component being introduced either preliminarily into carrier or together with catalytic complex. Process of isomerizing n-paraffins utilizing above-defined catalyst is also described.

EFFECT: lowered isomerization process temperature and pressure and increased productivity of catalyst.

17 cl, 3 tbl, 25 ex

FIELD: petrochemical process catalysts.

SUBSTANCE: invention relates to catalytic methods of isomerizing n-butane into isobutane and provides catalyst constituted by catalytic complex of general formula MexOy*aAn-*bCnXmH2n+2-m, where Me represents group III and IV metal, x=1-2, y=2-3, An- oxygen-containing acid anion, a=0.01-0.2, b=0.01-0.1; CnXmH2n+2-m is polyhalogenated hydrocarbon wherein X is halogen selected from a series including F, Cl, Br, I, or any combination thereof, n=1-10, m=1-22, dispersed on porous carrier with average pore radius at least 500 nm and containing hydrogenation component. Method of preparing this catalyst is also disclosed wherein above-indicated catalytic complex is synthesized from polyhalogenated hydrocarbon CnXmH2n+2-m wherein X, n, and m are defined above, group III and IV metal oxide, and oxygen-containing acid anion, and dispersed on porous carrier with average pore radius at least 500 nm, hydrogenation component being introduced either preliminarily into carrier or together with catalytic complex. Process of isomerizing n-butane into isobutane utilizing above-defined catalyst is also described.

EFFECT: lowered butane isomerization process temperature and pressure and increased productivity of catalyst.

13 cl, 1 tbl, 24 ex

FIELD: exhaust gas neutralization catalysts.

SUBSTANCE: catalyst contains at least one zeolite and additionally at least one oxide carrier selected from alumina, silica, titanium dioxide, and aluminum silicate, and also at least one precious metal selected from platinum, palladium, rhodium, and iridium. The latter are characterized by average oxidation degree below +2.5, average number of metal ligands more than 3, and average number of oxygen ligands less than 3, whereas precious metal atoms are present on zeolites and oxide carriers in the form of crystallites with average particle size 1-6 nm. Catalyst is prepared on an solid cellular element, for which oxide carriers and zeolites are first separately impregnated with precious metal precursors and then calcined in yet wet state by blowing them into gaseous combustion gases at 500-1000°C for 0.1 to 10 sec. Thereafter, common coating dispersion is processed, which is further used to coat solid cellular element. Coating is then dried, calcined, and reduced.

EFFECT: increased catalytic activity, prolonged lifetime of catalyst, and lowered minimum working temperature at which carbon monoxide and hydrocarbons start being catalytically converted.

10 cl, 8 tbl, 11 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: 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

The invention relates to catalysts used in the dehydrogenation of hydrocarbons, and to methods of using catalysts

The invention relates to a catalytic method implementing the reaction of steam reforming of ethanol in order to obtain a synthesis gas or enriched hydrogen gas mixture, which can be used in various industries, including hydrogen energy, for example, as fuel for fuel cells
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