The catalyst for high-temperature combustion of hydrocarbon fuel (options)

 

(57) Abstract:

The invention relates to the preparation of catalysts for deep oxidation of organic compounds. The catalyst can be used in the processes of high-temperature combustion of the hydrocarbon fuel and the treatment of industrial gas emissions and vehicle exhaust. The problem solved by the invention: improvement of thermostability magnetoluminescence catalyst at temperatures of its use 1100-1300oWith increasing service life of the catalyst under these conditions. This is achieved by the fact that as the source of aluminum compounds use the product of thermal decomposition of gibbsite containing a mixture-Al2O3and-Al2O3in the ratio (65-85 wt.%) -Al2O3and (35-15% by weight) -Al2O3, in the following ratio, wt.%: compounds of manganese in terms of MnO23-10, the carrier - aluminum oxide - rest. The media may further comprise modifying additives of oxides of magnesium, lanthanum, cerium or a mixture. The proposed catalytic composition can be applied as a secondary coating applied to the native complex geometric shapes, for example, B. p. f-crystals, 4 PL.

The invention relates to the field of chemistry, namely the preparation of catalysts for deep oxidation, used to process high-temperature combustion of hydrocarbon fuel in the flue gases of industrial plants. Temperature range implementation of these processes is 400-1300oWith that determines the requirement for high thermal stability of the catalysts.

It is known that the oxides of manganese and oxide systems based on them, for example, halomonadaceae, are effective catalysts for deep oxidation. Catalysts based on oxides of manganese contain individual oxides, usually MnO2or mixed with oxides of other elements. Individual oxides prepared by thermal decomposition of salts of manganese (II) or precipitation of manganese hydroxide with subsequent annealing [z Jaworska-Galas, W. Mista, J. Wrzyszcz, M. on show include //Catal. Lett., 1994, V. 24, p. 133]. Mixed catalysts are prepared by impregnation of a granular carrier with solutions of salts of Mn (II), for example, nitrates or acetates of manganese [P., tsyrulnikov, C. S. Salnikov, etc. //Kinu. and Catala, 1991, T. 32, 2, S. 439] a mixture of the corresponding oxides (such as oxides of aluminum, oxides of manganese) and then what to their low activity in oxidation reactions of hydrocarbons and carbon monoxide after high temperature overheating up to 1100-1300oC.

Closest to the technical nature of the claimed is manganocolumbite catalyst for deep oxidation of organic compounds and carbon monoxide, containing, after annealing at 900 to 1000oWith 2.7-11.5 wt.% Mn (or 4.3-20.2 wt.% per MnO2) on a medium consisting of 72-95 wt.% -Al2O3and sheet 18-5 wt.% (+)-Al2O3and derived from different source hydroxides of aluminum (pseudoboehmite, bayerite, hydro-argillite) [U.S. Pat. RF 2063803, IPC601 J 23/34, publ. 20.07.96]. Of these hydroxides at 550oWith the formed low-temperature oxides, type -, -, -Al2O3, respectively; and at temperatures above 1000oWith the mix-and-Al2O3[Z. R. Ismagilov, R. A. Skrbina, N. A. Koryabkina. //Alumina media: production, properties and application in catalytic processes for environmental protection. (Ser. Ecology. Vol. 50), Novosibirsk, 1998, 82 S.]. In the presence of manganese indicated a mixture of phases of Al2O3there is, according to the prototype, at 900-1000oWith and provides high activity of deposited manganese.

The catalyst of the prototype is prepared by impregnating one of the forms of alumina media (pseudoboehmite, bayerite, Al2O3, -Al2O32with the subsequent stages of drying, calcination at 500oWith and thermo-activation in the range of 900-1000oC.

The main disadvantage of this catalyst is limited (900-1000oC) temperature in the region of its application. In real conditions the processes of high-temperature combustion of hydrocarbon fuels where possible overheating to 1300oWith the use of such a catalyst is impractical, because at temperatures above 1000oWith the activity falls.

The problem solved by the invention: improvement of thermostability magnetoluminescence catalyst at temperatures of its use 1100-1300oWith increasing service life of the catalyst under these conditions.

This is achieved by the fact that as the source of aluminum compounds, a mixture of Al2ABOUT3and-Al2ABOUT3in particular, aluminum oxide, obtained from the product of thermal decomposition of gibbsite (formed in the catalytic heat generator) after processing in the low-alumina [Z. R. Ismagilov, R. A. Skrbina, N. A. Koryabkina. //Alumina media: production, properties and application in catalytic processes protect okrugayw> and disordered oxide structure type-Al2ABOUT3for example, in the ratio: (85-65% by weight) -Al2ABOUT3+ (35-15% by weight) -Al2ABOUT3. The presence in the medium of low-temperature disordered phase-Al2ABOUT3promotes the formation of highly dispersed compounds of manganese with-and-Al2ABOUT3. A more complete interaction with the low-temperature aluminium oxide provides a more stable manganocolumbite compounds that can provide a high activity of the catalysts after calcination at 1100-1300oC. Additionally increase the stability, and hence the service life of the catalyst at these temperatures is achieved by introducing into the original medium single-or double-modifying additives (2-15 wt.%) oxides of Mg, La or CE.

In addition, manganocolumbite catalysts proposed composition can be used as an active secondary coating in amounts of 10-25 wt. % media complex geometry, such as a block of ceramic media (cell blocks or multi-tile) based on aluminosilicate (block Al-Si-O), ceramic and metal highly permeable porous material is Oia 50% degree of conversion of methane (T50%CH4) after annealing at temperatures of 500oWITH 900oWITH 1100oWITH 1300oC for 4 h To evaluate thermal stability of the additionally measured the activity of the catalysts after calcination at 1100oC for 20 hours the Reaction of deep oxidation of methane chosen as the model reaction on the basis that the catalysts, oxidizing methane is the most stable of hydrocarbons, are active in oxidation reactions of other hydrocarbons and carbon monoxide. The tests were carried out in running the installation under the following conditions: the addition of catalyst 0.5 g, initial concentration of CH4- 1 vol.% in the air, the volumetric feed rate of the gas mixture - 1000 h-1.

The invention is illustrated by the following examples.

Example 1 (comparative).

Sample industrial catalyst ICT-12-40 with a content of 10 wt.% MnO2and temperature of annealing 950oC.

Example 2 (the prototype).

10 g-Al2ABOUT3with a specific surface area (Sbeats) 220 m2/g, having a water capacity of 0.43 ml/g, soaked in water holding capacity of the aqueous solution of manganese nitrate given concentration.

The impregnated sample dried at 1102).

Example 3.

10 g of granulated aluminum oxide, 85% -Al2ABOUT3+15% -AI2ABOUT3, (Sbeats=190 m2/g), previously calcined at 550oC for 4 h and having a water capacity of 0.60 ml/g, soaked in water holding capacity of the aqueous solution of manganese nitrate given concentration. The impregnated sample dried at 110oWith constant stirring for 2 hours After the stage of drying the catalyst calcined at temperatures of 500, 900, 1100 and 1300oC. the Time of annealing are listed in table 1.

The content of manganese in the catalyst is 5.4 wt.%.

Example 4.

Similar to example 3.

The difference is that for cooking take 10 g of granulated aluminum oxide, 65% -Al2O3+35% -Al2O3, (Sbeats=180 m2/g). The content of manganese in the catalyst is 4.9 wt.%.

Example 5.

Similar to example 3, but the original media pre-modified by the addition of 8 wt.% La2ABOUT3.

The content of manganese in the catalyst is 5.2 wt.%.

Example 6.

Analogous to example 5, but the original media pre-modified by the addition of 2 wt.% La2
Analogous to example 5, but the original media pre-modified by the addition of 15 wt.% La2ABOUT3.

The content of manganese in the catalyst is 6.0 wt.%.

Example 8.

Similar to example 3, but the original media pre-modified by the addition of 8 wt.% SEO2.

The content of manganese in the catalyst is 5.4 wt.%.

Example 9.

Similar to example 3, but the original media pre-modified by the addition of 2 wt.% MgO.

The content of manganese in the catalyst is 3.0 wt.%.

Example 10.

Similar to example 3, but the original media pre-modified additives 2 wt.% MgO and 12 wt. La2ABOUT3.

The content of manganese in the catalyst is 4.3 wt.%.

Example 11.

Similar to example 4, but the original media pre-modified by the addition of 5 wt.% MgO.

The content of manganese in the catalyst is 3.7 wt.%.

Example 12.

Similar to example 4, but the original media pre-modified additives 5 wt.% MgO and 8 wt.% La2ABOUT3.

The content of manganese in the catalyst is 5.2 wt.%.

The content of manganese in the catalyst is 5.2 wt.%.

Example 14.

Similar to example 3, but the original carrier calcined at 1200oC for 4 h

The content of manganese in the catalyst is 8.1 wt.%.

Example 15.

Analogously to example 5, but modified carrier calcined at 1200oC for 4 h

The content of manganese in the catalyst is 5.0 wt.%.

Example 16.

Similar to example 3, but the manganese content in the finished catalyst is 9.8 wt.%.

Example 17.

Analogous to example 5, but the manganese content in the finished catalyst is 10 wt.%.

Table 1 presents data on the activity manganocolumbite catalysts in the reaction of deep oxidation of methane.

From table 1 it is seen that, according to the invention, the activity of catalysts based media (65-85% and 15-35%-Al2O3), including modified, after calcination at 500oWith, at 10-80oWith superior activity of the comparative sample (example 2) prepared in conditions close to one of the examples described in the prototype.

After about what aktivnosti known industrial catalyst ICT-12-40 (example 1) and comparative example (example 2): 50% methane conversion on all of the above catalysts is achieved in the temperature range - 420-450oC.

After annealing at 1300oWith the proposed catalysts in comparison with the known industrial catalyst ICT-12-40 (example 1) and manganocolumbite catalyst on the basis of-Al2ABOUT3(example 2) have a significantly higher activity. Thus, the table shows that 50% methane conversion on the catalysts containing-Al2ABOUT3with modifying additives of oxides of La, Mg, CE (examples 5-7, 9-13, 15) or without them (examples 3, 4, 14), is achieved at temperatures at 65-120oWith lower in comparison with the known catalyst ICT-12-40 (example 1) and comparative catalyst on the basis of-Al2ABOUT3(example 2). This allows to significantly extend the temperature region of use of the present catalyst.

In addition, the modification of the media containing-Al2ABOUT3, additives of oxides of La, Mg and CE (2-15 wt.%) allows to increase thermostability of the proposed catalysts, and hence their service life, which follows from the data on the activity of these catalysts after their long-term calcinations (20 h) at 1100oFrom table 1, examples 5, 8, 9, 15). Temperatures reach 50% conversion of methane to these catalysts 60-70oSince n is OK oxides of La, Mg and CE (examples 3, 14), and at 150-160oWith lower compared with a catalyst based-Al2ABOUT3(example 2).

Thus, according to the invention, it is possible to provide a high activity manganocolumbite catalysts proposed composition in the temperature range from 500 to 1300oC.

Examples 18-26 (catalysts with a secondary coating suspension type) illustrate the possibility of the formation of active secondary coating containing 80 wt.% one of the catalysts prepared in accordance with examples 3-17, and 20 wt.% in the calculation of Al2ABOUT3inorganic binder, which is used, for example, pseudoboehmite.

Example 18.

ITEM based on metallic Ni or Ni-Cr (specific weight of 0.4-0.6 g/cm3the cell size of 2-3 mm, Sbeats= 0.1-0.5 m2/g) is immersed for 20 minutes in a suspension that provides secondary coverage to 80 wt.% the catalyst according to example 3 and 20 wt. % inorganic binder. After removal of excess slurry current air sample is dried first at room temperature for 24 hours and at a temperature of 110oC for 2 hours, and then calcined at a temperature of 900oC for 4 hours.

Example 20.

Similar to example 19. The difference lies in the fact that the finished catalyst contains 15 wt.% secondary coverage.

Example 21.

Analogously to example 18. The difference lies in the fact that the suspension contains a catalyst according to example 14. The finished catalyst contains 16 wt.% secondary coverage.

Example 22 (comparative).

Analogously to example 18. The difference lies in the fact that the suspension contains a catalyst according to example 2. The finished catalyst contains 15 wt.% secondary coverage.

Example 23.

Analogously to example 19. The difference is that an active secondary coating is applied to ITEM based on Tio2(specific weight of 0.5 g/cm3the cell size of 2-3 mm, Sbeats= 10 m2/g, pore volume of water (V)-0.2 ml/g) with an external diameter of 75 mm and a height of 20 mm, the Finished catalyst contains 17 wt.% secondary coverage.

Example 24.

Analogously to example 19. The difference is that an active secondary coating is applied to ITEM based on Si+SiC (specific weight of 0.2 g/cm3

Example 25.

Analogously to example 19. The difference is that an active secondary coating is applied to ITEM based on cordierite + mullite (specific weight of 0.3 g/cm3the cell size of 2-3 mm, Sbeats=1 m2/g) with external parameters HH mm, the Finished catalyst contains 15 wt.% secondary coverage.

Example 26.

Analogously to example 19. The difference is that an active secondary coating is applied to a block of ceramic-based media aluminosilicate (block Al-Si-O) with external dimensions of HH mm (the size of the channels 2x2 mm, wall thickness 0.4 mm, Sbeats=15 m2/g, V-0.25 ml/g). The finished catalyst contains 15 wt.% secondary coverage.

Example 27.

Analogously to example 19. The difference is that an active secondary coating is applied to a monolithic multi-channel ceramic tile-based aluminosilicate (tile Al-Si-O) with external dimensions of HH mm (diameter of 1 mm, wall thickness 1 mm, Sbeats=15 m2/g, V-0.3 ml/g). The finished catalyst contains 10 wt.% secondary coverage.

Examples 28-33 (catalysts with a secondary coating impregnating type) illustrate the possibility of the formation of active vtorichnoie, used for preparation of one of the catalysts according to examples 3-17, and 20 wt. % inorganic binder (Al2ABOUT3);

b) impregnation of the block obtained in paragraph a), the aqueous solution of manganese nitrate is similar to examples 3-17.

Example 28.

and ITEM on the basis of metal Ni-Cr (specific weight of 0.4-0.6 g/cm3the cell size of 2-3 mm, Sbeats=0.1-0.5 m2/g) is immersed for 20 minutes in a suspension that provides secondary coverage to 80 wt.% composition (85%-Al2O3+15%-Al2O3) appropriate medium according to example 3, and 20 wt.% inorganic binders. After removal of excess slurry current air sample is dried first at room temperature for 24 hours and at a temperature of 110oC for 2 hours, and then calcined at a temperature of 500oC for 4 hours.

Ready media contains 15 wt.% secondary coverage.

b) ITEM with secondary coverage under item (a) impregnated on capacity solution of manganese nitrate given concentration. The sample is dried at a temperature of 110oC for 2 hours and then calcined at a temperature of 900oC for 4 hours. The manganese content in the secondary coating is 5 Issa content of manganese in the secondary coating is 10 wt.%.

Example 30.

Analogous to example 28. The difference lies in the fact that for forming the secondary coating is used, the suspension containing composition composition (85% -Al2O3+15% -Al2O3modified 8 wt.% La2O3) corresponding to the carrier according to example 5. The manganese content in the secondary coating 5 wt.%.

Example 31.

a) Unit Al-Si-O (size channels 2x2 mm, wall thickness 0.4 mm, Sbeats=15 m2/g, V- 0.25 ml/g) is immersed for 20 minutes in a suspension that provides secondary coverage to 80 wt.% composition composition (85% -Al2O3+15% -Al2O3) appropriate medium according to example 3, and 20 wt.% inorganic binders. After removal of excess slurry current air sample is dried first at room temperature for 24 hours and at a temperature of 110oC for 2 hours, and then calcined at a temperature of 500oC for 4 hours.

Ready media contains 12 wt.% secondary coverage.

b) a Block of Al-Si-O with a secondary coating under item (a) impregnated on capacity solution of manganese nitrate given concentration. The sample is dried at a temperature of 110oC for 2 hours and then calcined at the e on MnO2.

Example 32.

Analogous to example 31. The difference lies in the fact that for forming the secondary coating is used, the suspension containing composition composition (85% -Al2O3+15% -Al2O3modified 8 wt.% La2O3) corresponding to the carrier according to example 5. The manganese content in the secondary coating is 5 wt.%.

Example 33 (comparative).

Analogous to example 31. The difference lies in the fact that for forming the secondary coating is used, the suspension containing-Al2O3corresponding to the carrier according to example 2. The manganese content in the secondary coating is 5 wt.%.

Analogously to examples 1-17, the activity manganocolumbite catalysts based media complex geometry is also characterized by the temperature reach 50% conversion of CH4. Data on the activity presented in tables 2, 3.

To assess thermal stability and stability of the catalysts in the reaction medium, the catalyst with a secondary coating in examples 20 and 22 with the temperature of annealing 900oWith subjected to processing in a reaction medium containing 9% of CH4when volume rate of flow is Antartic conditions. Data are presented in table 4.

1. The catalyst for high-temperature combustion of hydrocarbon fuel containing compounds of manganese and aluminum oxide, characterized in that as the source of aluminum compounds, a mixture-Al2O3and-Al2O3in relation 65-85 wt. % -Al2O3and 35-15 wt. % -Al2O3in the following ratio, wt. %:

Compounds of manganese in terms of MnO2- 3-10

Media - alumina - Rest

2. The catalyst p. 1, characterized in that the starting compound of aluminium is produced by thermal decomposition of gibbsite with subsequent annealing at 500-600oC.

3. The catalyst according to any one of paragraphs. 1 and 2, characterized in that the source carrier - aluminum oxide - further comprises modifying additives of oxides of magnesium, lanthanum, cerium or a mixture in the following ratio, wt. %:

Compounds of manganese in terms of Mno2- 3-10

Modifying additive in terms of oxide - 2-15

Media - alumina - Rest

4. The catalyst for high-temperature combustion of hydrocarbon fuel containing compounds of manganese and aluminum oxide, characterized the box is used as a secondary coating, incurred in the amount of 10-25 wt. % to the media.

5. The catalyst p. 4, characterized in that use media complex geometric shapes, for example, the unit cell structure, a monolithic multi-tile or highly permeable mesh material.

 

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