RU2134157C1 - Method of preparing catalyst for removing injurious impurities - Google Patents

Abstract

FIELD: catalyst production. SUBSTANCE: invention relates to oxide-type catalysts preferably useful in ozone decomposition processes that may be likewise used in processes of deep oxidation of injurious organic impurities, carbon monoxide, and hydrogen, and also for treatment of industrial gas emissions. Preparation of such catalysts includes agitation of active material consisting of copper or manganese compound and binding agent, granulation, drying and heat treatment of granules. According to invention, activated aluminum hydroxide is used as binding agent and active material consists of at least one of compounds of metals selected from the group including copper, manganese, cobalt, nickel, or their mixture. In this case, binding agent and active material are preliminarily activated in common or separately to obtain particles no greater than 50 mcm in size which, if activation has been carried out separately, are further combined. Resulting material is plasticized and extruded. Extrudate is partially dried and then thermally treated at 450-550 C to form catalyst containing 25-95% of catalytic metal oxides, 0.1% of alkali metal oxides, and binding agent to 100%. EFFECT: increased activity and strength of catalyst. 9 cl, 1 tbl, 10 ex

Description

 The invention relates to methods for producing oxide catalysts. The proposed catalyst is preferably used in the decomposition of ozone. The catalyst can also be used in the deep oxidation of harmful organic impurities, carbon monoxide, hydrogen or in the purification of industrial gas emissions.

Known composition for cleaning gases containing oxides of nitrogen, sulfur, ozone, gases with an unpleasant odor, containing H ₂ S, acetaldehyde, lower fatty acids and exhaust gases. The composition is a reaction product between a powder metal of the type Cr, Ni, Zn, Al, Mn, Fe, Cu, Sn, Co, or an alloy of these metals with particles ≤ 50 μm in size and one of the oxygen-containing polybasic acids. The composition may contain a solid base such as CaO, MgO, etc. The disadvantage is the complexity of the preparation of the catalyst and insufficiently high activity in the processes of deep oxidation of hydrocarbons and decomposition of ozone (US patent N 5171726, CL B 01 J 31/04, 1989).

 A known catalyst for the decomposition of ozone and a method for its production (US patent N 5221649, CL B 01 J 21/16, 23/34, 1992). The catalyst is an inactive carrier of the type: clay, carbon, manganese dioxide, onto which one of the metal oxides from the group Cu, Co, Fe, Ni, Ag is deposited. The composition of the catalyst, wt.%: 10-50 clay, 20-90 manganese dioxide and one of the metal oxides from the group of Co, Ni and Ag in an amount of 1-30% of the total amount of manganese oxide. The disadvantage of the catalyst is its low activity in the decomposition of ozone. When using clay in the composition of the catalyst, the strength of the catalyst in the presence of water vapor is markedly reduced.

 A known catalyst for the decomposition of ozone (US patent N 5002920, class B 01 J 21/06, 1989), which has an increased duration of operation, but it includes such expensive metals as Ti, Ag, Au. In addition, Pt, Ru, Re, Os, Rh, Pd additives are added to the catalyst (US Pat. No. 5,002,920, CL B 01 J 21/06, 1989). The disadvantage of the catalyst is the use in its preparation of scarce noble metals.

 A known method of producing a catalyst for the decomposition of ozone (Japanese application N (B4) N 4-35223, CL B 01 J 23/84, 1987), removal of carbon monoxide. In the preparation of the catalyst, alkaline solutions of potassium permangate are used, which leads to a decrease in the activity of the catalyst, and, in addition, in the process of preparing the catalyst there is a large amount of wastewater.

A known method of preparing a granular oxide-copper catalyst for complete oxidation to remove harmful impurities in gas mixtures (RF patent N 2085284, CL B 01 J 37/04, 23/83, 21/04 // B 01 J 23/83, 1995) . In this method, the catalyst is obtained from porous copper oxide and a binder, which is used as an X-ray amorphous alumina powder, they are crushed together, mixed and formed by extrusion. The catalyst preparation technology is non-waste, but the catalyst drawback is insufficient activity in the processes of removing harmful impurities, especially in the processes of ozone decomposition (RF patent N 2085284, class B 01 J 37/04, 23/83, 21/04 // B 01 J 23/83, 1995)
The closest solution is a method of producing a catalyst for the decomposition of harmful impurities, including mixing aqueous suspensions of electrolytic manganese dioxide and copper oxide with a binder, granule formation, drying, crushing and heat treatment. The catalyst has increased activity in the processes of cleaning dry gas-air mixtures from ozone. The disadvantage of the catalyst is the difficulty of obtaining it, a large amount of wastewater (RF patent N 1806008, CL B 01 J 37/04, 1991 - prototype)
The problem solved by the invention is to develop a catalyst for removing harmful impurities with high activity and strength.

The problem is solved by a method for producing a catalyst for removing harmful impurities, preferably for ozone decomposition, including mixing an active mass consisting of at least one metal compound selected from the group: copper, manganese, cobalt, nickel, or a mixture thereof, and a binder, molding granules, drying, heat treatment. Activated aluminum hydroxide is used as a binder, the active mass and the binder are preliminarily activated together or separately to obtain particles no larger than 50 microns, with separate activation of the components, they are mixed, then the catalyst charge is plasticized, formed with subsequent drying of the granules, heat treatment is carried out at a temperature of 450 -500 ^o C, and the catalyst has the following composition, wt.%:
At least one metal oxide selected from the group: copper, manganese, cobalt, nickel, or a mixture thereof - 25-95
Oxide or mixture of alkali metal oxides - Not more than 0.10
Binder - Else
Copper oxide is preferably prepared by thermal decomposition of malachite.

 Silica gel or calcium oxide, or calcium hydroxide, or talyum, or mixtures thereof, in an amount of up to 10% by weight are added to the activated aluminum hydroxide.

 Before use, the active mass and the binder are washed with water until the content of alkali metal group compounds (in terms of oxides) is not more than 0.1 wt.%.

 After activation, the number of particles with a size of less than 20 microns is at least 70 wt.%.

 At the stage of mixing the components, the plasticization of the catalyst mixture is carried out with water.

 Plasticization of the catalyst charge is carried out with an aqueous acid solution capable of forming water-soluble aluminum salts.

 The catalyst charge is plasticized with an aqueous acid solution based on the acid module Mk = 0.13-0.20.

 With separate activation of the components, the binder is additionally plasticized at room temperature before mixing with the active mass.

Thus, the proposed method for producing a catalyst, in contrast to the known one, is characterized by a number of significant differences:
- activated aluminum hydroxide is used as a binder;
- the active mass is at least one of a metal compound selected from the group: copper, manganese, cobalt, nickel or a mixture thereof;
- the binder and the active mass are preliminarily subjected to activation together or separately to obtain particles no larger than 50 microns in size;
- with separate activation of the components from then mixed;
- the catalyst mixture is plasticized;
- the catalyst mixture is formed with subsequent drying of the granules;
- heat treatment is carried out at a temperature of 450-550 ^o C;
- the catalyst has the following composition, wt.%:
At least one metal oxide selected from the group: copper, manganese, cobalt, nickel, or a mixture thereof - 25-95
Oxide or mixture of oxides of alkali metals - Not more than 0.10
Binder - Else
The proposed set of distinctive features allows to obtain a catalyst for removing harmful impurities, which has high activity and strength.

 The preparation conditions and test results of the catalysts are presented in the table.

 The catalysts of the prototype and obtained by the present method were tested in the processes of decomposition of ozone, deep oxidation of hydrocarbon and carbon monoxide in model mixtures in excess oxygen.

 As a measure of the catalytic activity of the catalysts in the ozone decomposition reaction, the degree of ozone decomposition is taken at fixed values of the humidity of the gas-air mixture, volumetric flow rate, and temperature.

As a measure of the catalytic activity of the catalysts in the n-butane oxidation reaction, the reaction rate (cm ³ C ₄ H _{10 /} g.s.) of n-butane oxidation at a volume fraction of 0.2% and a temperature of 400 ^o C. was taken. Higher reaction rate oxidation of butane corresponds to a more active catalyst.

 The temperature at which an 85% degree of oxidation of carbon monoxide is reached is taken as a measure of the catalytic activity of the catalyst in the oxidation of carbon monoxide. The lower the temperature at which the carbon monoxide reaches 85% oxidation, the higher the activity of the catalyst.

 The mechanical strength of the granules by crushing along the generatrix was determined on an MP-9C device. As a measure of mechanical strength, the ultimate compressive force is taken, at which the destruction of the granules occurs, referred to the conditional section.

 Example 1 (prototype).

Take 30 kg of paste of copper oxide with a moisture content of 60% (CuO content is 12.0 kg), 160 kg of paste of electrolytic manganese dioxide with a moisture content of 50% (MnO ₂ content is 80 kg), load into the mixer, add 150 l of water, mix in for 1.5 hours. The resulting suspension is filtered, the precipitate is discharged into a paddle mixer with a steam jacket. 11 kg of binder (bentonite powder) is added and the plasticization process is carried out for 1 h until the paste reaches a moisture content of 33%. Granules are formed on a screw granulator (at a pressure of 40 atm and a temperature of 105-120 ^o C), the latter are dried at a temperature of 80 ^o C for 12 hours. The dried granules are crushed, the 1-3 mm fraction is sieved and the heat treatment is carried out in a fluidized bed furnace at a temperature of 290 ^o C for 20 minutes

The catalyst has the following composition, wt.%:
MnO ₂ - 77.67
CuO - 11.65
Binder - 10.68
Example 2

950 g of copper oxide are mixed with 76.4 g of activated aluminum hydroxide. The resulting powder mixture is washed with 4 times the amount of distilled water with stirring, filtered, the wet cake is dried at a temperature of 110 ^° C. for 6 hours. The washed powder mixture is activated and placed in a mixer. Particle size less than 50 microns is 100 wt.%. The plasticizer of the mixture is carried out with water for 30-40 minutes until the composition reaches a moisture content of 30-33 wt.%, After which the catalyst mass is formed.

The formed granules are dried in air at room temperature for 12 hours, then dried at a temperature of 110 ^° C. for 6 hours. The catalyst is calcined at 550 ^° C. for 4 hours, maintaining a temperature rise rate of 150 ^° C./h
The resulting catalyst has the following composition, wt.%:
CuO - 95
Alkali metal oxide - 0.03
Al ₂ O ₃ - Other
Example 3

The catalyst preparation conditions are similar to Example 2, only the washing steps from alkali metal compounds and the activation of copper oxide and aluminum hydroxide are carried out separately. Calcination of the catalyst is carried out at a temperature of 450 ^o C for 4 hours

The resulting catalyst has the following composition, wt.%:
CuO - 95
Alkali metal oxide - 0.015
Al ₂ O ₃ - Other
Example 4

The catalyst preparation conditions are similar to Example 2, only copper oxide is obtained by thermal decomposition of the basic carbonic salt of copper (malachite). 1321 g of malachite are calcined at a temperature of 450 ^° C. for 2 hours. The yield of copper oxide is 950 g. Then, 950 g of copper oxide and 76.4 g of activated aluminum hydroxide are mixed and subjected to joint activation.

Plasticization of the catalyst charge is carried out with an aqueous solution of nitric acid at the rate of Mk = 0.13 in relation to aluminum oxide (435 cm ^{3 of} water are added to 5 cm ³ with a concentration of 800 g / l HNO ₃ ).

The resulting catalyst has the following composition, wt.%:
CuO - 95
Alkali metal oxides - 0.018
Al ₂ O ₃ - Other
Example 5

 The preparation conditions of the catalyst are similar to example 2, only the activation of 250 g of copper oxide and 1147 g of aluminum hydroxide is carried out separately. Then 250 g of aluminum hydroxide (of the total amount of aluminum hydroxide) is plasticized with an aqueous solution of nitric acid at the rate of Mk = 0.20 with respect to alumina at atmospheric pressure and room temperature.

Then, copper oxide, powdered aluminum hydroxide and acid-treated aluminum hydroxide with a total moisture content of 75% by weight are mixed in a blender-mixer for 40 minutes. The catalyst mass is formed into granules, dried in air at room temperature for 10 hours, dried at a temperature of 110 ^° C. for 6 hours and calcined at 550 ^° C., withstanding a temperature rise rate of 220 ^° C./h.

The resulting catalyst has the following composition, wt.%:
CuO - 25
Alkali metal oxides - 0.1
Al ₂ O ₃ - Else
Example 6

The conditions for the preparation of the catalyst are similar to example 2, only for the preparation of the catalyst use 250 g of manganese dioxide and 1147 g of activated aluminum hydroxide. After the activation stage, the content of particles less than 40 microns in size is 97.5 wt.%. Plasticization of the catalyst charge is carried out with an aqueous solution of hydrochloric acid at the rate of Mk = 0.20 with respect to aluminum oxide (420 cm ^{3 of} water are added to 178 cm ^{3 of} acid with a concentration of 300 g / l HCl).

The resulting catalyst has the following composition, wt.%:
MnO ₂ - 25
Alkali metal oxides - 0.045
Al ₂ O ₃ - Other
Example 7

The catalyst preparation conditions are similar to Example 2, only the following components are used for the preparation of the catalyst: 450 g of copper oxide, 158.8 g of cobalt carbon dioxide, 66.1 g of manganese carbon dioxide, 100 g of thallium and 459 g of activated aluminum hydroxide. Plasticization of the catalyst mixture is carried out with an aqueous solution of acetic acid at the rate of Mk = 0.15 with respect to alumina (474 cm ^{3 of} water is added to 29 cm ^{3 of} acid with a concentration of 900 g / l CH ₃ COOH).

The granules are calcined at a temperature of 500 ^o C, withstanding a rate of temperature rise of 180 ^o C / h

The resulting catalyst has the following composition, wt.%:
CuO - 45
CoO - 10
MnO ₂ - 5
Alkali metal oxides - 0.085
Talum - 10
Al ₂ O ₃ - Other
Example 8

The catalyst preparation conditions are similar to Example 2, only the following feedstock is used for the preparation of the catalyst: 300 g of copper oxide, 300 g of nickel oxide, 66.1 g of manganese dioxide, 50 g of cobalt oxide, 50 g of calcium oxide, 66.1 calcium hydroxide and 306 g of activated aluminum hydroxide. After the activation stage, the content of particles smaller than 20 microns is 77.3 wt.%, Plasticization of the catalyst mixture is carried out with an aqueous solution of nitric acid at the rate of Mk = 0.15 with respect to alumina (to 26 cm ^{3 of} acid with a concentration of 700 g / l HNO ₃ add 460 cm ³ water).

The resulting catalyst has the following composition, wt.%:
CuO - 30
NiO - 30
MnO ₂ - 5
CoO - 5
Alkali metal oxides - 0.07
CaO - 10
Al ₂ O ₃ - Other
Example 9

The catalyst preparation conditions are similar to Example 2, only the following components are used for the preparation of the catalyst: 200 g of manganese dioxide, 100 g of copper oxide, 917.6 g of activated aluminum hydroxide, 50 g of calcium oxide and 50 g of silica gel. Plasticization of the catalyst charge is carried out with an aqueous solution of nitric acid at the rate of Mk = 0.13 with respect to aluminum oxide (500 cm ^{3 of} water are added to 60 cm ^{3 of} acid with a concentration of 800 g / l HNO ₃ ).

The resulting catalyst has the following composition, wt.:%
MnO ₂ - 20
CuO - 10
Alkali metal oxides - 0.09
CaO - 5
SiO ₂ - 5
Al ₂ O ₃ - Other
Example 10

The catalyst preparation conditions are similar to Example 2, only copper oxide is obtained by thermal decomposition of the basic carbonic salt of copper (malachite). 1182 g of malachite is calcined at 450 ^° C. for 2 hours. The yield of copper oxide is 850 g. The washing and activation steps of 850 g of copper oxide, 50 g of cobalt oxide and 152.9 g of activated aluminum hydroxide are carried out separately. Then the components are mixed and plasticization of the catalyst mixture is carried out with water to obtain a composition with a moisture content of 30 wt.%.

The resulting catalyst has the following composition, wt.%:
CuO - 85
CoO - 5
Alkali metal oxides - 0.03
Al ₂ O ₃ - Other
As can be seen from the above examples, the proposed method allows to obtain catalysts of different composition. The composition of the catalyst can be selected depending on operating conditions, gas humidity, type of harmful impurities, etc.

Claims (8)

1. A method of producing a catalyst for removing harmful impurities, preferably for decomposition of ozone, comprising mixing an active mass consisting of a metal compound and a binder, granule formation, drying, heat treatment, characterized in that activated aluminum hydroxide is used as the binder, the active mass is at least one of the metal compounds selected from the group: copper, manganese, cobalt, nickel, or a mixture thereof, a binder and an active mass are preliminarily subjected to activation together or zdelno to a particle size of not more than 50 microns, with separate activation components are mixed, then the catalyst is plasticized batch, shaped extrudates, followed by wilting, heat treatment is performed at 450 - 550 ^o C and the catalyst has the following composition, wt.%:
At least one metal oxide selected from the group: copper, manganese, cobalt, nickel, or a mixture thereof - 25 - 95
Oxide or mixture of oxides of alkali metals - Not more than 0.10
Binder - Else
2. The method according to claim 1, characterized in that the copper oxide is obtained, preferably, by thermal decomposition of malachite.  3. The method according to p. 1, characterized in that to the activated aluminum hydroxide is added either silica gel, or calcium oxide, or calcium hydroxide, or talyum, or a mixture thereof in an amount of up to 10 wt.%.  4. The method according to claim 1, characterized in that the active mass and the binder are washed before use with water until the content of the compounds of the alkali metal group (in terms of metal oxides) is not more than 0.10 wt.%.  5. The method according to claim 1, characterized in that after activation, the number of particles with a size of less than 20 microns is at least 70 wt.%.  6. The method according to p. 1, characterized in that the plasticization of the catalyst mixture is carried out with water.  7. The method according to p. 1, characterized in that the plasticization of the catalyst mixture is carried out with an aqueous solution of an acid capable of forming water-soluble aluminum salts.  8. The method according to PP. 1 and 7, characterized in that the plasticization of the catalyst mixture is carried out with an aqueous acid solution based on the acid module Mk = 0.13 - 0.20.  9. The method according to claims 1, 7 and 8, characterized in that when the components are separately activated, the binder is additionally plasticized at room temperature before mixing with the active mass.

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