A method of producing a catalyst for deep oxidation of hydrocarbons

 

(57) Abstract:

Usage: in catalytic chemistry, in particular in methods for producing catalyst for deep oxidation of hydrocarbons. The inventive method provides for mixing of the components in the presence of water with the addition of heat-resistant mineral fibers. The formation of lead with simultaneous withdrawal of fluid by vacuum, followed by drying and heat treatment. When this mixing is conducted in aqueous solution of transition metal salts, are able to form simple and complex oxides with spinel structure selected from the group comprising chromium, iron, cobalt, Nickel, copper. The total salt concentration is 100 to 600 g/l Mineral fiber injected to the concentration of the suspension of 0.1 - 0.8 wt.%. Before drying, the molded mass is heated to a temperature of from 75 to 95°C. for 1 h.p. f-crystals, 1 table.

The invention relates to the chemical industry, in particular the production of catalysts deposition for besplamennoju catalytic oxidation.

Such catalysts are used in the heat source based on the catalytic oxidation of hydrocarbons.

It is used in industry catalysts deep oxidized is ascioti to significant overheating, stable characteristics for a long time, the efficiency at high speed fuel supply.

Known method of preparing catalysts for deep oxidation of hydrocarbons, in which the catalysts are prepared by impregnation of fibrous materials (e.g., silica or kaolin fiber) with a solution of nitrate salts of cobalt and chromium, or by deposition on a carrier corresponding hydroxides.

However, this method is characterized by inhomogeneous distribution of the active component on the carrier surface, which leads to minor mechanical strength of the catalyst. In addition, for the application of the catalyst components in the amount of 30-55% by weight of the carrier should be repeated impregnation of the carrier, which leads to increase the time of preparation of the catalyst.

Known method of preparing a composite material for oxidation of hydrocarbon fuels in which the molded fibrous material includes mineral fiber dispersion in water with the inorganic binder and the subsequent dilution of the suspension, squeezing and molding material, drying and consolidation of the binder, impregnating the resulting material is property allows to obtain a gas-permeable composite material made of asbestos and ceramic fibers. The disadvantage of this method is a multistage process in its implementation, which leads to increased costs of time (labor).

There is a method of preparation of the catalyst for oxidation of hydrocarbons and carbon monoxide by mixing the catalytically active compounds of transition metals (manganese dioxide, chromium oxide and heat-resistant mineral fibers with a diameter of 5-9 μm, using as a binder Na-bentonite. Known catalyst is prepared by mixing the above components with the subsequent formation of the mixture in the presence of a binder in a dry process with simultaneous granulation mixture. A disadvantage of the known catalyst comprising a cemented conglomerates - large bulk, the presence of a significant number of inefficient use of the compounds.

Closest to the proposed to the technical essence and the achieved effect (prototype) is a method for preparing catalysts for deep oxidation of hydrocarbons, including the production of the molding material by mixing the components, wt. % : Manganese dioxide 20-40 chromium Oxide 5-20 PA-bentonite 2-8,5

Heat-resistant mineral fiber with the Rest of the binder, while the Poltva which use Na-bentonite or polyvinyl acetate, in the presence of water to obtain a suspension, then injected under stirring mineral fiber diameter of 1-15 μm and molding is carried out at a ratio of solid and liquid phases, is equal to 1:50 to 1:250, with simultaneous removal of water by vacuum. When carrying out the known method upon receipt of the catalyst on stage filter formed of waste water contaminated with harmful compounds of chromium, manganese, and organic binder that creates a tense ecological situation.

In the known composition of the catalyst comprises an active insoluble components, mineral fibers and binder in the form of a dispersion to bond the fiber between itself and the fixing insoluble active ingredients, however, due to the lack of communication between the binder, fiber and other components they are poorly retained in the fibrous mass, which results in reduced stability of the catalyst to thermocycles (sequence of rapid heating and cooling). The presence of the binder reduces the content of active compounds of the catalyst. In operation when the temperature is burning out the organic binder, which results in further lowering of physico-chemical characteristics the x velocities of gas flow.

The purpose of the invention is the improvement of the mechanical properties, performance characteristics, reducing the complexity and environmental stress in the manufacture of the catalyst.

This objective is achieved in that in the method of producing a catalyst for deep oxidation of hydrocarbons, including the offset components in the presence of water with the addition of heat-resistant mineral fibers, molding with simultaneous removal of fluid by vacuum, followed by drying and heat treatment, the mixture is conducted in aqueous solution of transition metal salts, are able to form simple and complex oxides with spinel structure selected from the group comprising chromium, iron, cobalt, Nickel, copper while the total salt concentration is 100 to 600 g/l, mineral fiber injected to the concentration of the suspension of 0.1-0.8 wt.%, and before drying, the molded mass is heated to a temperature of 75-95aboutC.

Distinctive features of this method are:

use as the active material of aqueous solutions of salts of transition metals are able to form simple and complex oxides with spinel structure; such metals include Cu, Ag, Zn, Cd, Th, Ti, V, Cr, Mo, W, Mn, Re, Fe, Co, Ni; total up of slurry concentration 0.1-0.8 wt.%;

heating the molded mass before drying to a temperature of 75-95aboutWith the help of infrared radiation from an external source in the wavelength range 1-5 µm intensity 10-15 kW/m2.

Improved performance characteristics, mechanical properties, reducing the complexity and environmental stress in the manufacture of the catalyst is explained by the selected combination of active ingredients and process parameters, a uniform distribution of the active components on the surface of elementary fibers, and the amount of the resulting material.

The best indicators are provided only within the specified limits the total concentration of a solution of salts of 100-600 g/l

The concentration of a solution of salts of transition metals of less than 100 g/l reduces the concentration of active components in the catalyst, and consequently, reduces the operating characteristics of the catalyst. By increasing the concentration of solutions of more than 600 g/l increases the density of the catalyst, reduced gas permeability, elasticity.

The choice of the interval of slurry concentration (mineral fiber solid phase, solution, active components - liquid phase) in the range of 0.1-0.8 wt. % allows get katete, the permeability and high mechanical properties (strength, flexibility).

When the ratio of the solid and liquid phases is less than 0.1% decreases the performance of the molding process. With a ratio of more than 0.8 wt.% there is intense flocculation (flocculation) of the suspension, which leads to violation of the homogeneity of the molded material, and this in turn determines the uniformity of gas permeability and gas-dynamic mode, thereby providing the catalyst for the uniformity of the heat flux.

The original humidity weight 250-300% is achieved by removing excess moisture by vacuum in the vacuum of 0.2-04, ATM.

Selected limits heating this mass 75-95aboutTo exclude the possibility of decomposition of the active catalyst components on the oxides and ensure the preservation of the structure of the material during the heating of the deep and intense evaporation. At temperatures above 95aboutWith is an uncontrolled decomposition of the active components on the oxides, and at temperatures below 75aboutWith increasing duration of the process of preparation of the catalyst.

The parameters of infrared radiation from an external source (wavelength of 1-5 μm and intens who assy, as well as the optimal combination of optical characteristics of the emitter, the staging environment and the heated mass, which are characterized by high selectivity and are determined by the wavelength used thermal radiation and bandwidth of the material. The maximum radiant energy for a given material is allocated on the section of the wavelengths of 1-5 μm, which corresponds to the greatest absorptive capacity of the material in the wet state.

The best performance is achieved when the selected limits heating of the mass of the infrared radiation from an external source.

The process of preparation of the catalyst ends up drying (convective) at temperatures up to 95aboutC and heat treated at a temperature of 500-700aboutC. during the heat treatment causes the decomposition of salts of the above metals with the formation of volatile compounds that are removed from the reaction zone and catalytically active components mounted on the fibrous substrate. The catalytically active components are a mixture of amalfitani simple or complex oxides of the respective metals having a spinel structure. As microadditives (promoter) to improve operational hazy.

P R I m e R 1. To a mixture consisting of 1280 g setevogo cobalt nitrate (Co(NO3)26H2O) and 560 g deviational chromium nitrate (Cr(NO3)39H2O) add 3 l of distilled water at a temperature of 50 5aboutC; then, with vigorous stirring, adding water in small portions to bring the volume of the solution up to 8 HP To the resulting solution was added 40 g of thin quartz fiber with a diameter of 0.8 to 2 μm and is dispersed in the roll for 2-3 minutes

While the total concentration of salts in a solution of 230 g/l, the concentration of silica fibers in suspension to 0.5 wt.%.

The resulting suspension is molded on the molding table and remove excess solution by degassing under vacuum 02,0.4 ATM. The resulting material is heated by infrared radiation from an external source with a wavelength of 3.0 μm with an intensity of 13 kW/m2for 150 s to a temperature of 80 3oC, dried in a convection dryer at 85 10aboutAnd thermoablative for 1 h at 600 10aboutC.

The catalyst is an elastic fibrous tile, containing in its composition, wt.%: Quartz fiber 77,0 Co3O49,5 Co2CrO411,5 CoCr2O2CrO4and CoCr2O4have spinel structure. The relative amounts of oxides of various compositions were calculated from the intensities of the corresponding peaks in the x-ray.

P R I m m e R 2. Analogously to example 1, except that for the preparation of 8 liters of a solution to take 3200 grams of Co(NO3)26H2O and 1400 grams Cr(NO3)39H2O, which corresponds to the total concentration of salts 575 g/l

The composition of the catalyst, wt. %: Quartz fiber 55,0 Co3O418,0 Co2CrO422,5 CoCr2O44,5

P R I m e R 3. Analogously to example 1, except that for the preparation of 8 liters of a solution to take 640 grams of Co(NO3)26H2O and 280 grams CR(NO3)39H2O, which corresponds to the total concentration of salt 115 g/L.

The catalyst composition, wt.%: Quartz fiber 88,0 Co3O45,0 Co2CrO46,0 CoCr2O41,0

P R I m e R 4. Analogously to example 1, except that 8 l of a solution for the preparation of suspensions add 65 g thin quartz fiber, which corresponds to the concentration of fibers in suspension 0,81%.

The catalyst composition similar to that shown in example 1.

P R I m e R 5. Analogichnogo fiber, which corresponds to the concentration of fibers in the suspension of 0.13%.

The catalyst composition similar to that shown in example 1.

P R I m e R 6. Analogously to example 1, except that heating of the molded mass is carried out at a wavelength of infrared radiation from an external source to 0.8 μm.

The catalyst composition similar to that shown in example 1.

P R I m e R 7. Analogously to example 1, except that heating of the molded mass is carried out at a wavelength of infrared radiation from an external source 6 microns.

The catalyst composition similar to that shown in example 1.

P R I m e R 8. Similar to example 1, except that for the preparation of 8 liters of a solution to take 250 grams of Co(NO3) 6H2O, 320 g of Fe(NO3)39H2O and 230 grams Cr(NO3)39H2O, which corresponds to the total concentration of salt 100 g/l, the concentration of fibers in the suspension is similar to example 1 (0,5%).

The catalyst composition, wt.%: Quartz fiber 89,0 CoFe2O45,5 Co2CrO42,0 CoCr2O43,5

P R I m e R 9. Analogously to example 1, except that for the preparation of 8 liters of a solution to take 1920 Co(NH3)26H2O, 1440 g of Ni(NO g/L.

The catalyst composition, wt.%: Quartz fiber 59,0 NiCo2O423,0 NiCr2O413,0 Co2CrO45,0

P R I m e R 10. Analogously to example 1, except that for the preparation of 8 l of solution take 215 g of Cu(NO3)26H2O and 585 g Fe(NO3)39H2O, which corresponds to the total concentration of salt 100 g/l

The catalyst composition, wt.%: Quartz fiber 90,0 CuFe2O410,0

P R I m e R 11. Analogously to example 1, except that for the preparation of 8 liters of a solution to take 1290 g of Cu(NO3)26H2O and 3500 g of Fe(NO3)39H2O, which corresponds to the total concentration of salts 598 g/l

The catalyst composition, wt.%: Quartz fiber 61,0 CuFe2O439,0

P R I m e R 12. Analogously to example 1, except that for the preparation of 8 liters of a solution to take 2100 g of cobalt acetate Co(CH3COO)24H2O, 360 g of chromic anhydride (CrO3and 0.010 g of platinum chloride PtCl4that represents the total concentration of salts 375 g/l

The catalyst composition, wt.%: Quartz fiber 63,0 Co3O414,0 Co2CrO418,5 CoCr2O44,5 Pt 0,0005

Physico-mechanical and operational characteristics of polycentrality.

Flexibility in this case means the ability of a material to maintain its integrity when it is bending on the cylindrical surface. Index of flexibility of taking the smallest diameter of the roller, when the winding on which the sample thickness of 5 mm will not be detected cracks.

Indicators of catalytic activity are:

a) specific heat removal, i.e., the amount of heat released by passing through the catalyst with a given thickness of gasoline vapor in the operating mode in a unit of time, referred to the unit of surface of the tile;

b) complete oxidation of the fuel, calculated as the ratio of the volume of non-toxic oxidation products (i.e., no carbon monoxide) to their total in the operating mode in the first 100 hours of operation.

The analysis of the table shows that when the concentration of the salt solutions in the range 100-600 g/l catalyst has better physical-mechanical and operational characteristics. By increasing the concentration of solutions of more than 600 g/l increases the density of the catalyst, reduced flexibility, complicated by its heat treatment, which leads, in spite of the increase in the content of catalytically active components, to reduce operational pokazateli, but markedly reduced lifespan (example 3, 8, 10).

The use of suspensions with fiber content more than 0.8% makes it difficult to obtain a catalyst with uniform properties in the bulk of the material (example 4), and when the content in the suspension fiber less than 0.1% of the performance of the manufacturing process is reduced due to the necessary use of large quantities of solution (example 5).

Heating the molded mass of the infrared radiation with a wavelength that is outside the specified limits (1-5 μm), reduces the efficiency of the process (examples 6, 7). Decreasing the intensity of the heat flux less than 10 kW/m2grows warm-up time. Increasing it above 15 kW/m2leads to intense evaporation in the material volume, heaving the molded mass and enhanced migration of active ingredients to the surface.

To obtain the catalyst of the proposed method, the concentration of metal salts in solution remains constant during repeated up to 40 times) use, which minimizes liquid effluents contaminated with heavy metal ions.

Thus, the proposed method allows to reduce the environmental tensions in the manufacture catalytical obtaining a catalyst with high physical and mechanical performance characteristics.

It should be noted that the proposed method is promising for the creation of technological equipment periodic and continuous action, and will also help to reduce labor and material costs of production and thereby reduce its cost.

1. A METHOD of producing a CATALYST for DEEP OXIDATION of HYDROCARBONS, comprising mixing the components in the presence of water with the addition of heat-resistant mineral fibers, molding with simultaneous removal of fluid by vacuum, followed by drying and heat treatment, characterized in that the mixing is conducted in aqueous solution of metal salts, are able to form simple and complex oxides with spinel structure selected from the group of chromium, iron, cobalt, Nickel and copper, while the total salt concentration is 100 to 600 g/l, mineral fiber injected to the concentration of the suspension of 0.1 - 0.8 wt.%, and before drying, the molded mass is heated to 75 - 95oC.

2. The method according to p. 1, characterized in that warming-up exercise infrared radiation from an external source in the wavelength range of 1 - 5 µm intensity of 10 to 15 kW/m2.

 

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