SU716584A1 - Method of preparing catalyst for organic substance deep oxidation - Google Patents

Description

one

The invention relates to the production of catalysts for the deep oxidation of organic substances, for example for burning the organic part of gaseous emissions, in particular, to the production of catalysts for deep oxidation consisting of metal oxides of variable valence and carrier.

A known method for the preparation of a catalyst for highly efficient purification of exhaust gases from carbon oxides and nitrogen fl. The catalyst is obtained by mixing cobalt and aluminum hydroxides in a ratio of 1: 0.8 and subsequent calcination for 2-5 hours at 500-800 C. The preparation of the catalyst according to this method has a significant disadvantage — the use of a high ratio of cobalt hydroxide to aluminum hydroxide, which greatly increases the cost of the catalyst.

There is also known a method for preparing a catalyst for deep oxidation, containing cobalt oxide and a carrier f2. Catalyst is obtained by heating a mixture of cobalt compounds that decompose when heated to form cobalt oxide,

aluminum nitrate and calcium nitrate to the first temperature (250-300 ° C) at which cobalt oxide is formed, but calcium nitrate does not decompose. Then, the catalyst particles are formed and heated to the second temperature (650-980 ° C) at which calcium nitrate reacts with aluminum compounds for a time sufficient to complete the reaction between them, with the second temperature not exceeding the temperature at which the cobalt oxide is deactivated. The use of aluminum and calcium nitrates in the process of obtaining a catalyst increases its cost and increases the amount of gaseous emissions in the form of nitrogen oxides during calcination of the catalyst.

A method for producing a catalyst for purifying exhaust gases is described. The catalyst is obtained by heating a mixture of silica powder, cobalt salt powder and a curing polymer composition. As silica, use is made of ground, kaolin, talc or bentonite, cobalt acetate and / or cobalt nitrate is used as a cobalt salt, and

a composition that has a decomposition temperature lower than the temperature of the catalytic reaction, and which can be oxidized by the action of 6 hardeners or heat. Heating the mixture at a temperature of less than causes curing of the polymer resin, decomposition of the metal salt, and calcining the catalyst. In this method of producing a catalyst, a distinguishing feature is the use of a polymer composition. The use of organic substances (cobalt acetate and polymer composition), on the one hand, increases the cost of the catalyst, and on the other hand, it does not allow to obtain a highly active catalyst. Of the known methods for producing a catalyst for the deep oxidation of organic substances by the number of operations and their sequence, the closest technical solution is. The method for producing catalyst 4, which consists in mixing, cobalt nitrate with a support, alumina, is added a sufficient amount of water to completely dissolve the cobalt nitrate, then evaporate the water, causing

The temperature in the reaction zone,

The degree of conversion of methanol,%

The specific oxidation rate of methanol, g of methanol / kg of catalyst. The aim of the invention is to obtain a catalyst for the deep oxidation of organic substances, which has high catalytic activity and low cost, the goal is achieved in the proposed method, which includes shifting the solution of cobalt nitric acid with a carrier, followed by suspensions, cyiiiKy pastes and calcination of the catalytic mass, as a carrier use the combustion ash of coal, composition, weight. %: - - -, SiOz, 43-55 AiEj Oj16-22 Fe Oj12-18 CaO 5-12 MgOi-3 CuO0.05-0.7 Products of incomplete combustion of coal (loss after calcination, vania) (Sec. i.), and the mixing of the water-soluble cobalt compounds with the ash is carried out at the initial pH. suspensions of 0.54

o6pa3ON known amount of cobalt on alumina. The catalyst was dried at 100 s and calcined at 400-1300 s for at least 30 minutes. Calcination results in the formation of cobalt aluminate with a blue spinel structure.

The disadvantage of the described method is that synthetic catalyst is used in the preparation of the catalyst.

 aluminum, the catalyst quickly loses its activity in the oxidation of carbon monoxide to dioxide, and therefore it needs to be regenerated frequently. All this increases the cost as

5 of the catalyst itself and the purification process using it. In addition, catalysis; 1, obtained by this method is not sufficiently active. For comparison, a catalyst was prepared with a cobalt content.

13, wt.% And its activity in the deep oxidation of methanol was determined. For this purpose, 0.1 g of catalyst was loaded into the reactor and missed

5 vapor-air mixture containing

1.2% by volume of methanol. The results are presented in table 1.

Table

280

270

300

70

87

57

2400 2980

1955 The use of the proposed method for the preparation of a catalyst not only increases the activity of the oxide-cobalt catalyst for the deep oxidation of organic substances by 1.2-1.4 times, but also reduces the cost of 1 ton of catalyst according to CI, with the cost of the catalyst obtained by the prototype and having the same weight ratio the active component to the carrier, at 300-400 rubles. and also partially dispose of waste during the combustion of coal at CHP. The catalytic activity of the obtained catalysts of the present method was determined on a flow-circulation installation in the deep methanol oxidation reaction and evaluated by the specific oxidation rate expressed in g of methanol / kg of catalyst. Example 1. Pour 60 ml of distilled water and a solution into a heat-resistant beaker. 4.93 g of cobalt co {NOg) 2-6H20 are added to it under stirring, then 10 g of coal ash of the composition,% by weight: SiOg 46 ;. ACnOj 18.2; 15.6; Sab 11.8; MgO 2.0; CuO 0.48; ppt 5.1 .. After stirring for 10 minutes, the suspension was adjusted to 1.0 by adding the necessary amount of a 10-30% solution of nitric acid to the suspension and the suspension was evaporated at ОО-EO С, then the paste was dried at lOO-llOC for 8 h and calcined catalyst

The temperature in the reaction zone,

The degree of conversion of methanol,%

The specific oxidation rate of methanol, g of methanol / kg of catalyst h

Example 2. 60 ml of distilled water is poured into a heat-resistant beaker and 3.45 g of cobalt nitrate is dissolved in it, 10 g of coal ash of the composition coal are added, wt.%: SiO 43.2; 16,4s

at 4 hours. A supported oxide cobalt catalyst containing 10% by weight of cobalt is obtained on the combustion ash of coal. lei. 0.1 g of the obtained catalyst is loaded into the reactor and the vapor-air mixture containing 1.2% by volume of methanol is passed at a volume rate of 20 l / h. The results are shown in table 2.

table 2

280

270

300

79.0 91.0

100

3120

2710

3430

, 16.4; CaO 11.6; MgO 2.6; CuO 0.7; P.P.P. 7.5. The remaining operations, as in example 1. Get the catalyst containing 7 weight.%

cobalt on the ashes of the combustion of coal. The results when: shown in table 3, table 3

Specific oxidation rate, methanol, g methanol / kg catalyst-h

Example 3. In a heat-resistant beaker, 60 ml of distilled water is poured and 6.4 g of cobalt nitrate are dissolved therein with stirring, 10 g of combustion ash of 5 5% coal of the composition, wt.% Are added: SiO2 54.7;

Temperature in the reaction zone, C270

The degree of conversion of methanol,% 83.2

The specific oxidation rate of methanol, g of methanol / kg catalyst is h2850

EXAMPLE 4 An oxide-cobalt catalyst is obtained, containing 10% by weight of cobalt on coal combustion ash, as in Example 1 / but with a different initial pH of the suspension.

2360 2720

3300

.Oz 20f3; Fe-jOj 12.1; CaO 5.8; MgO 1.9; CuO Oh; ppt 2,46. The remaining operations as in Example 1. A catalyst is obtained containing 13% by weight of cobalt on the coal ash. The results are shown in table 4.

Table 4

280 300 94.5 100

3240 3430

The results of determining the activity of samples of the same composition, depending on the initial pH of the suspension at a temperature of 280 ° C at 65, are listed in Table 5.

pH of suspensions

Increase degree IretKi Mötöy at 280 ° C,%

Specific icitopec-Tb oxidation of methanol at 280 / C, g of methanol / kg of catalyst h 3140

Formula. . 1. Method for producing a catalyst for the deep oxidation of organic substances, including a solution of cobalt nitrate with a carrier, followed by evaporation of the suspension, drying the paste and calcining the catalyst mass, so that with the aim of obtaining a catalyst increased activity, as well as its cost, as a carrier, use coal ash, and mixing is carried out at an initial pH of the suspension equal to 0.5-1.0, and the coal ash has the following composition in, wt.%: SiO243-55

AEgOz16-22

Table 5 1.0 2.0 3.0

0.5

91.0. 82.4 76.1

91.5

3120 2820 2510

FegOj12-18

CaO5-12

5 MdO1-3

SiO0.05-0.7

Incomplete Products

coal combustion 1-8.

Sources of information taken into account in the examination

 1. Japan patent No. 51-11596, cl. 2ei), 1973,

2 Patent of Great Britain 1310969, cl. In I, 1973.

3. For Japan No. 50-22955, cl. 1973.

4. For France 2228032, 0 кл. On 01.J., 1973 (prototype).

Claims (1)

1. A method of obtaining a catalyst for the deep oxidation of organic 15 substances, comprising mixing a solution of cobalt nitrate with a carrier, subsequent evaporation of the suspension, drying the paste and calcining ka. · Talizatornogo mass, with the exception of the fact that, in order to obtain a catalyst with increased activity, as well as reducing its cost, coal __ ash combustion is used as a carrier, and mixing is carried out at ** the initial pH of the suspension, equal to 0.51.0, and the ash of combustion of coal has the following composition, wt.%: SiO ₂ 43-55 Ae ₂ 0s 16-2230 Fe ₂ 0 ₃ CaO MDO CIO Products'complete combustion of coal 12-18 '5-12 1-3 0.05-0.7 1-8.