CN106732523B - Catalyst support and method of preparation - Google Patents
Catalyst support and method of preparation Download PDFInfo
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- CN106732523B CN106732523B CN201710094079.2A CN201710094079A CN106732523B CN 106732523 B CN106732523 B CN 106732523B CN 201710094079 A CN201710094079 A CN 201710094079A CN 106732523 B CN106732523 B CN 106732523B
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- B01D53/34—Chemical or biological purification of waste gases
- B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
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- B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
- B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
- B01D53/945—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC] characterised by a specific catalyst
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Abstract
The invention provides a catalyst carrier and a preparation method thereof. The method comprises the following steps: mixing a sodium aluminate solution and a modifier solution and spraying the mixture into a base solution so as to obtain a raw material mixed solution, wherein the base solution contains a dispersing agent; sequentially carrying out precipitation treatment and aging treatment on the raw material mixed liquor so as to obtain a precipitate; washing, drying and calcining the precipitate in sequence; subjecting the precipitate subjected to the calcination treatment to a pulverization treatment to obtain the catalyst carrier. The catalyst carrier prepared by the method has the advantages of long service life, good thermal stability, good oxygen storage performance, large specific surface area, large pore volume and the like.
Description
Technical Field
The invention relates to the field of materials, in particular to a catalyst carrier and a preparation method thereof, and more particularly relates to preparation of a modified alumina powder material of an automobile exhaust purification catalyst carrier.
Background
Along with the development of the automobile industry, the harm of automobile exhaust to human environment is attracting more and more attention. The harmful components in the automobile exhaust mainly comprise: carbon monoxide (CO), Hydrocarbons (HC), Nitrogen Oxides (NO)X) Sulfur dioxide (SO)2) And the like. In areas where motor vehicles are more popular, motor vehicle emissions have become a major source of urban air pollution.
The catalytic purification of automobile exhaust is one of the effective means for controlling the pollution of automobile exhaust. The carrier of the automobile exhaust catalyst is mainly alumina with a porous structure. The preparation method of the prior alumina catalyst carrier mainly comprises the following steps: impregnation, coprecipitation, sol-gel, mechanical mixing, and the like. The modified alumina produced by the coprecipitation method and the sol-gel method has the advantages of long service life, good high-temperature thermal stability, good oxygen storage performance, low chemical impurity content and the like.
However, the current catalyst support and the preparation method thereof still need to be improved.
Disclosure of Invention
The present application is based on the discovery and recognition by the inventors of the following facts and problems:
the existing catalyst carrier generally has the problems of non-ideal effect of catalytic purification of tail gas, serious attenuation of catalytic effect along with the increase of service time and the like. The inventor finds that the main reason is that the existing automobile exhaust catalysts are modified or porous alumina loaded with catalysts. When the automobile exhausts tail gas, the environmental temperature of the catalyst carrier can reach 800-1100 ℃ in a transient state, and the structure of part of alumina at the moment is gamma-Al2O3Conversion to alpha-Al2O3. And alpha-Al2O3With gamma-Al2O3Compared with the prior art, the specific surface area, the pore volume and the oxygen storage and release energyThe forces are all greatly reduced and the light-off temperature is increased, thus not effectively catalyzing the conversion of NO, CO and incompletely combusted hydrocarbons (hydrocarbons) to N2、CO2And H2And O, further influencing the catalytic purification effect of the tail gas.
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.
In view of this, in a first aspect of the invention, a method of preparing a catalyst support is provided. According to an embodiment of the invention, the method comprises: mixing a sodium aluminate solution and a modifier solution and spraying the mixture into a base solution so as to obtain a raw material mixed solution, wherein the base solution contains a dispersing agent; sequentially carrying out precipitation treatment and aging treatment on the raw material mixed liquor so as to obtain a precipitate; washing, drying and calcining the precipitate in sequence; subjecting the precipitate subjected to the calcination treatment to a pulverization treatment to obtain the catalyst carrier. The method is simple and convenient to operate and low in production cost, and the prepared catalyst carrier has the advantages of long service life, good thermal stability, good oxygen storage performance, large specific surface area, large pore volume and the like.
According to the embodiment of the invention, the concentration of the sodium aluminate in the sodium aluminate solution is 80-300 g/L. Thereby, a catalyst carrier with a moderate particle size is advantageously obtained.
According to an embodiment of the invention, the modifier in the modifier solution contains at least one of lanthanum, cerium, zirconium, praseodymium, neodymium, barium, dysprosium. Thereby, the performance of the catalyst carrier can be further improved.
According to the embodiment of the invention, the modifier solution is obtained by adding the modifier into a nitric acid solution with the mass fraction of 15-35%, and the content of the modifier in the modifier solution is 1-40 wt% based on the mass of Al in the sodium aluminate solution. Thereby, the performance of the catalyst carrier can be further improved.
According to an embodiment of the present invention, the dispersant includes at least one of PEG-2000, sodium dodecylbenzenesulfonate, polyvinylpyrrolidone, tween 80, polyethylene glycol fatty acid ester, and polyoxyethylene ester of fatty acid. This can further increase the specific surface area, pore volume, and particle size distribution of the catalyst support obtained by the method.
According to the embodiment of the invention, the content of the dispersing agent in the base solution is 0.1-10 wt% based on the mass of Al in the sodium aluminate solution. Thereby, the specific surface area, the pore volume and the particle size distribution of the catalyst carrier obtained by the method are further improved.
According to the embodiment of the invention, when the raw material mixed solution is subjected to the precipitation treatment in sequence, the temperature of the precipitation treatment is 20-80 ℃, and the pH value of the raw material mixed solution is 6.5-8.5. Thereby, the high-temperature thermal stability, the specific surface area and the pore volume of the catalyst carrier obtained by the method are further improved.
According to the embodiment of the invention, the temperature of the aging treatment is 65-95 ℃, and the time of the aging treatment is 1-100 hours. Therefore, the method is favorable for further improving the pore volume of the catalyst carrier obtained by the method and enabling the catalyst carrier to have better high-temperature thermal stability.
According to an embodiment of the present invention, before the calcination treatment, further comprising: carrying out washing sodium removal treatment on the precipitate, wherein the washing sodium removal treatment is realized by the following steps: and (2) washing the precipitate for multiple times by adopting an ammonia water solution with the pH value of 8.0-10.0, wherein the solid-to-liquid ratio of the ammonia water solution to the precipitate is (9-15): 1, the washing temperature is 60-95 ℃, and the washing time is 10-60 minutes. This can further improve the activity of the catalyst carrier.
According to the embodiment of the invention, the temperature of the calcination treatment is not lower than 800 ℃, and the time of the calcination treatment is 1.5-4 hours. This is advantageous in further improving the high-temperature thermal stability of the catalyst support obtained by the method.
According to an embodiment of the invention, the comminution process is a jet comminution process. Thereby, it is advantageous to obtain a catalyst support having an appropriate particle size.
In another aspect of the invention, a catalyst support is provided. According to an embodiment of the present invention, the catalyst support is prepared by the method described above. Therefore, the catalyst carrier has at least one of the advantages of long service life, good thermal stability, good oxygen storage performance, large specific surface area, large pore volume and the like.
According to an embodiment of the present invention, γ -Al in the catalyst carrier is at a temperature of not less than 800 degrees celsius2O3The content is not less than 50 wt%.
Drawings
FIG. 1 shows a schematic flow diagram of a preparation method according to one embodiment of the present invention;
FIG. 2 shows a schematic flow diagram of a preparation process according to another embodiment of the present invention;
FIG. 3 shows a schematic flow diagram of yet another preparation method according to the present invention;
FIG. 4 shows a scanning electron microscope image of a catalyst support according to one embodiment of the invention; and
fig. 5 and 6 show the high-temperature thermal stability test results of the catalyst carrier according to one embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
In a first aspect of the invention, a method of preparing a catalyst support is presented. According to an embodiment of the invention, with reference to fig. 1, the method comprises:
s100: mixed spraying
According to an embodiment of the present invention, in this step, a sodium aluminate solution and a modifier solution are mixed and sprayed into a base solution so as to obtain a raw material mixed solution.
According to an embodiment of the present invention, the sodium aluminate solution may be prepared by alkali-dissolving aluminum hydroxide. In particular, metallurgical grade aluminum hydroxide may be mixed with flake caustic and dissolved. In the obtained sodium aluminate solution, the concentration of sodium aluminate can be 80-300 g/L. Thereby, a catalyst carrier with a moderate particle size is advantageously obtained.
According to the embodiment of the invention, the modifier solution can be obtained by adding the modifier into a nitric acid solution with the mass fraction of 15-35%. The modifier solution may contain 1 to 40 wt% of a modifier based on the mass of Al in the sodium aluminate solution. Thereby, the performance of the catalyst carrier can be further improved. The specific type of the modifier is not particularly limited according to the embodiment of the present invention, and those skilled in the art can select an appropriate exhaust gas purifying catalyst modifier according to actual needs. For example, according to an embodiment of the present invention, at least one of lanthanum, cerium, zirconium, praseodymium, neodymium, barium, dysprosium may be contained in the modifier. Thereby, the performance of the catalyst carrier can be further improved.
According to the embodiment of the invention, the sodium aluminate solution and the modifier solution are mixed and then added into the base solution in a spraying manner. The base solution is a solution containing a dispersant, and the dispersant can comprise at least one of PEG-2000, sodium dodecyl benzene sulfonate, polyvinylpyrrolidone, Tween 80, polyethylene glycol fatty acid ester and polyoxyethylene fatty acid ester. According to the embodiment of the present invention, the content of the dispersant in the base solution may be 0.1 to 10 wt% based on the mass of Al in the sodium aluminate solution. This can further increase the specific surface area and pore volume of the catalyst carrier obtained by the method.
Through a large number of experiments and intensive research, the inventor finds that the mixture of the sodium aluminate solution and the modifier solution is added into the base solution in a spraying mode to form the raw material mixed solution, so that the high-temperature thermal stability, the specific surface area and the pore volume of the obtained catalyst carrier can be remarkably increased. And moreover, the catalyst carrier with moderate granularity is obtained by mixing in a spraying mode.
S200: aging by precipitation
According to an embodiment of the present invention, in this step, the raw material mixed liquid is subjected to the precipitation treatment and the aging treatment in this order to obtain the precipitate.
According to the embodiment of the invention, when the raw material mixed solution is subjected to precipitation treatment, the temperature of the precipitation treatment can be 20-80 ℃, and the pH value of the raw material mixed solution can be 6.5-8.5. In this step, the specific manner of controlling the temperature at the time of the precipitation treatment and the specific manner of adjusting the pH are not particularly limited. For example, the temperature of the raw material mixture may be maintained within the above temperature range during the precipitation treatment by heating the raw material mixture including, but not limited to, a water bath. When the pH value of the raw material mixed liquor exceeds or is less than the range, the pH value of the raw material mixed liquor can be adjusted by adding weak acid or weak base solution into the raw material mixed liquor or adjusting the flow of the acid and the base of the precipitation raw material, so that the pH value of the raw material mixed liquor can be kept within the range during the precipitation treatment. The specific time of the precipitation treatment is also not particularly limited, and the time of the precipitation treatment may be 2 hours according to an embodiment of the present invention.
According to the embodiment of the present invention, after the precipitation treatment, the raw material mixed solution after the complete precipitation may be subjected to an aging treatment. The inventor finds out through a large amount of experiments that the pore diameter and the high-temperature stability of the finally obtained catalyst carrier can be adjusted by proper aging treatment. According to the embodiment of the invention, the temperature of the aging treatment can be 65-95 ℃, and the time of the aging treatment can be 1-100 hours. When the time of the aging treatment is too short, the pore diameter of the catalyst carrier cannot be effectively increased. However, if the aging treatment is carried out for a long time, the high-temperature stability of the catalyst support is liable to be deteriorated.
According to the embodiment of the present invention, after the raw material mixture is sequentially subjected to the precipitation treatment and the aging treatment, the obtained precipitate and the remaining raw material mixture may be separated by a simple filtering operation. The filtered residue is the precipitate, and the filtrate produced by filtering contains the raw material mixture which is not completely reacted. Therefore, the filtrate obtained by filtration is evaporated and concentrated to obtain sodium nitrate and pure water. Pure water may be used to dilute or make up the solution, while sodium nitrate may be sold as a by-product. Therefore, the method is beneficial to further improving the economic benefit of the method for production enterprises.
According to an embodiment of the present invention, in order to further improve the effect of the subsequent processing, referring to fig. 2, the method may further include:
s10: removing sodium by washing
According to an embodiment of the invention, in this step, the precipitate obtained from the precipitation ageing is subjected to a washing and sodium-removing treatment. Thus, NaNO in the precipitate can be removed3And further, the performance of the finally obtained catalyst carrier can be further improved. Specifically, the precipitate may be washed several times with an aqueous ammonia solution having a pH of 8.0 to 10.0 in this step. According to a specific embodiment of the present invention, in this step, the precipitate may be subjected to multiple counter-current washing with an aqueous ammonia solution having a pH value within the above-mentioned range. When the countercurrent washing is carried out, the solid-to-liquid ratio of the ammonia solution added into the precipitate for countercurrent washing to the precipitate and the precipitate can be (9-15): 1. in order to further improve the efficiency and effect of sodium removal by washing, the temperature of washing can be 60-95 ℃. The time of each countercurrent washing is 10-60 minutes. Repeating the above countercurrent washing process for several times to remove NaNO from the precipitate3The content is reduced to 1000 ppm. For example, according to an embodiment of the present invention, the Na content in the precipitate may be reduced to several hundred ppm or less after 8 counter-current washes. This can further improve the activity of the catalyst carrier.
According to the embodiment of the invention, in order to further reduce the production cost and improve the utilization rate of raw materials, the washing solution (namely, ammonia solution) can be recovered in the step. Because the washing liquid contains a large amount of NaNO3Therefore, the washing solution can be used as a solvent for preparing the sodium aluminate solution. Therefore, the dosage of the caustic soda flakes is saved, the production cost can be saved in one step, and the utilization rate of raw materials is improved.
It will be appreciated by those skilled in the art that the precipitate, after washing and sodium removal, may be first dried in a drying cabinet and then subjected to subsequent treatment steps.
S300: calcination treatment
According to an embodiment of the invention, in this step, the precipitate that has been subjected to the washing and sodium removal treatment is subjected to a calcination treatment. According to an embodiment of the present invention, the temperature of the calcination treatment may be not less than 800 degrees celsius. According to the embodiment of the present invention, the specific time of the calcination treatment is not particularly limited. For example, the time of the calcination treatment may be 1.5 to 4 hours. This is advantageous in further improving the high-temperature thermal stability of the catalyst support obtained by the method.
S400: pulverizing treatment
According to the embodiment of the present invention, in order to further improve the performance of the catalyst support prepared by the method, the calcined precipitate may be subjected to a pulverization treatment. Thereby, it is advantageous to obtain a catalyst support having an appropriate particle size. According to a particular embodiment of the invention, the comminution process may be jet comminution. This makes it possible to easily adjust the particle size of the precipitate.
For further ease of understanding, the specific scheme for preparing the catalyst support by this method is briefly described below in connection with some examples of the invention:
according to an embodiment of the present invention, referring to fig. 3, a sodium aluminate solution may be prepared by first mixing and dissolving aluminum hydroxide and flake caustic. To improve the efficiency and effectiveness of the dissolution, the aluminum hydroxide and the flake caustic soda can be first weighed and mixed in accordance with the sodium aluminate concentration described above. And then, diluting and filtering the mixed solution, and adding the filtered filter residue into the solution again, so that the dissolving efficiency of solid raw materials (aluminum hydroxide and flake caustic soda) can be improved on the premise of ensuring the accurate concentration of the prepared sodium aluminate solution. Meanwhile, according to the content of the modifier described above, the modifier is dissolved by a nitric acid solution to obtain a modifier solution. Mixing the sodium aluminate solution and the modifier solution, and adding the mixture into the base solution in a spraying mode. After the precipitation treatment and the aging treatment, the obtained precipitate is fully filtered and washed, the filter residue is washed and sodium-removed (washing and filtering as shown in the figure), and the subsequent drying, calcining and airflow crushing are carried out, so that the catalyst carrier is obtained. The filtrate was filtered and washed, and evaporated and concentrated to obtain sodium nitrate and pure water.
In conclusion, according to the method provided by the embodiment of the invention, the automobile exhaust purification catalyst carrier with appropriate particle size, low chemical impurity content, large specific surface area, large pore volume and long service life can be obtained through simple operation and low production cost. The catalyst carrier has Al content at 800 deg.c2O3The crystal form can still be kept as gamma-form. Moreover, the catalyst carrier obtained through the steps of mixed spraying, precipitation aging, calcination treatment and the like can ensure that the modifier is not only attached to Al2O3The surface of the catalyst carrier is taken into the inside of the alumina crystal lattice, so that the catalyst carrier prepared by the method has excellent product performance.
In another aspect of the invention, a catalyst support is provided. According to an embodiment of the present invention, the catalyst support is prepared by the method described above. Thus, the catalyst carrier has all the features and advantages of the catalyst carrier prepared by the method described above, and thus, the description thereof is omitted. Generally speaking, the catalyst carrier has at least one of the advantages of long service life, good thermal stability, good oxygen storage performance, large specific surface area, large pore volume and the like.
For example, according to an embodiment of the present invention, γ -Al in the catalyst carrier at a temperature of not less than 800 degrees Celsius of the catalyst carrier2O3The content of Na can also be not less than 50 wt%2The O content is less than 600ppm, and the fresh specific surface area is 170-240 m2The pore volume is between 0.4 and 1ml/g, and the specific surface area in an aging state is between 100 and 145m2The pore volume is between 0.2 and 1 ml/g.
The present invention is illustrated below by way of specific examples, which are intended to be illustrative only and not to limit the scope of the present invention in any way, and unless otherwise specified, conditions or steps not specifically recited are generally conventional and reagents and materials used therein may be commercially available.
Example 1
1) The aluminum hydroxide is dissolved by alkali to prepare NaAlO with the concentration of 100g/l2And (3) solution.
2) Preparing a nitric acid solution with the mass fraction of 23%, and adding 4% (calculated by alumina) of lanthanum nitrate modifier into the nitric acid solution.
3) A base solution containing PEG-20005% (calculated by alumina) is prepared.
4) The sodium aluminate solution and the nitric acid solution are sprayed into the base solution in a parallel flow mode, the precipitation temperature is 50 ℃, and the pH value of the precipitate is 6.5-7.0;
5) the precipitation slurry was aged at 90 ℃ for 72 h.
6) And filtering and washing the slurry, wherein the washing is carried out by countercurrent washing for 8 times by using weak ammonia water solution with the pH value of 9.0, the liquid-solid ratio is 10:1, the washing and sodium removal temperature is 85 ℃, and the washing and sodium removal time is 20 Min.
7) And after washing and sodium removal, drying filter residues in a drying box.
8) The modified aluminum hydroxide is calcined at 800 ℃ for 2 h.
9) And airflow crushing after calcination.
The obtained product has impurity Na content of 550ppm, apparent density of 0.30g/l, specific surface area of 187.9352m at 800 deg.C for 2 hr2G, the pore volume is 0.891677 ml/g; specific surface area of 143.9452m at 1000 ℃ for 4h2The microstructure of the product in/g and a pore volume of 0.813590ml/g is shown in FIG. 4.
Example 2
1) The aluminum hydroxide is dissolved by alkali to prepare NaAlO with the concentration of 100g/l2And (3) solution.
2) Preparing a nitric acid solution with the mass fraction of 23%, and adding a combined modifier of 4% (calculated by alumina) of lanthanum nitrate and 0.4% (calculated by alumina) of praseodymium nitrate into the nitric acid solution.
3) Preparing a base solution containing PEG-20002% (calculated by alumina).
4) And (3) spraying the sodium aluminate solution and the nitric acid solution into the base solution in a parallel flow manner, wherein the precipitation temperature is 50 ℃, and the precipitation pH value is 7.0-7.8.
5) Aging the precipitation slurry at 80 ℃ for 24 h;
6) and filtering and washing the slurry, wherein the washing is carried out by countercurrent washing for 8 times by using weak ammonia water solution with the pH value of 9.0, the liquid-solid ratio is 10:1, the washing and sodium removal temperature is 85 ℃, and the washing and sodium removal time is 30 Min.
7) And after washing and sodium removal, drying filter residues in a drying box.
8) The modified aluminum hydroxide is calcined at 800 ℃ for 2 h.
9) And airflow crushing after calcination.
The obtained product has impurity Na content of 380ppm, apparent density of 0.33g/l, specific surface area of 191.6866m at 800 deg.C for 2 hr2G, the pore volume is 0.823945 ml/g; specific surface area of 129.8733m at 1000 ℃ for 4h2G, pore volume 0.622642 ml/g.
Example 3
1) The aluminum hydroxide is dissolved by alkali to prepare NaAlO with the concentration of 100g/l2And (3) solution.
2) Preparing a nitric acid solution with the mass fraction of 18%, and adding 1.6% (calculated by alumina) of lanthanum nitrate, 0.4% (calculated by alumina) of dysprosium nitrate, 12% (calculated by alumina) of cerium nitrate and 24% (calculated by alumina) of zirconium nitrate into the nitric acid solution to form a combined modifier.
3) A base solution containing Tween 801% (calculated on alumina) and polyethylene glycol fatty acid ester 3% (calculated on alumina) was prepared.
4) And (3) spraying the sodium aluminate solution and the nitric acid solution into the base solution in a parallel flow manner, wherein the precipitation temperature is 50 ℃, and the pH value of the precipitate is 6.7-7.5.
5) The precipitation slurry was aged at 85 ℃ for 10 h.
6) And filtering and washing the slurry, wherein the washing is carried out by countercurrent washing for 8 times by using weak ammonia water solution with the pH value of 8.5, the liquid-solid ratio is 15:1, the washing and sodium removal temperature is 85 ℃, and the washing and sodium removal time is 40 Min.
7) And after washing and sodium removal, drying filter residues in a drying box.
8) The modified aluminum hydroxide is calcined at 800 ℃ for 2 h.
9) And airflow crushing after calcination.
The obtained product has impurity Na content of 230ppm, apparent density of 0.45g/l, specific surface area of 162.7554m at 800 deg.C for 2 hr2G, the pore volume is 0.432440 ml/g; specific surface area of 100.5092m at 1000 ℃ for 4h2G, pore volume 0.234246 ml/g.
200km vehicle-mounted experiment:
the current national V emission standards are shown in the following table:
25g (which is the limit of testing and is usually tested by 30 g) of modified alumina prepared by adopting the embodiment carries noble metal, and then the modified alumina is coated on the framework of the catalytic purifier to carry out the real vehicle operation test, so that the test effect is excellent. Taking the modified catalyst carrier prepared in example 1 as an example, the modified catalyst carrier can maintain a good catalytic purification effect (compare with national V automobile exhaust emission standard) in the 200Km vehicle-mounted test process. The specific test result is as follows: THC, CO, NOx、CO2、CH4The results of the tests were 0.035g/km, 0.392g/km, 0.013g/km, 361g/km, 0.003g/km, 0.032g/km and 15.5g/km, respectively.
And (3) high-temperature thermal stability characterization:
the modified catalyst supports prepared in the above examples were subjected to a high-temperature calcination treatment to test their high-temperature thermal stability. After the high-temperature calcination treatment at 1000 ℃, at least 50% of the alumina in the above embodiment is still gamma-shaped. Taking the catalyst carrier prepared in example 1 as an example, referring to fig. 5, after calcining at 800 ℃ for 2h, the XRD pattern of the catalyst carrier shows that the alumina crystal form is still gamma-type; after calcination at 1000 c for 4h, referring to fig. 6, the XRD pattern of the catalyst support shows that also only about 45% of the alumina is converted to form theta.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (11)
1. A method of preparing a catalyst support, comprising:
mixing a sodium aluminate solution and a modifier solution and spraying the mixture into a base solution so as to obtain a raw material mixed solution, wherein the base solution contains a dispersing agent;
sequentially carrying out precipitation treatment and aging treatment on the raw material mixed liquor so as to obtain a precipitate;
washing, drying and calcining the precipitate in sequence;
subjecting the precipitate subjected to the calcination treatment to a pulverization treatment to obtain the catalyst carrier,
wherein the sodium aluminate solution is prepared by alkali dissolving aluminum hydroxide, the modifier solution is obtained by adding the modifier into 15-35% nitric acid solution by mass fraction,
in the sodium aluminate solution, the concentration of the sodium aluminate is 80-300 g/L;
in the modifier solution, based on the mass of Al in the sodium aluminate solution, the content of the modifier is 1-40 wt%,
the specific surface area of the catalyst carrier in an aging state is 100-145 m2The pore volume is between 0.2 and 1 ml/g.
2. The method of claim 1, wherein the modifier in the modifier solution comprises at least one of lanthanum, cerium, zirconium, praseodymium, neodymium, barium, dysprosium.
3. The method of claim 1, wherein the dispersant comprises at least one of PEG-2000, sodium dodecylbenzene sulfonate, polyvinylpyrrolidone, tween 80, polyethylene glycol fatty acid ester, and polyoxyethylene ester of fatty acid.
4. The method as claimed in claim 3, wherein the dispersing agent is contained in the base solution in an amount of 0.1 to 10 wt% based on the mass of Al in the sodium aluminate solution.
5. The method according to claim 1, wherein when the raw material mixture is subjected to the precipitation treatment sequentially, the temperature of the precipitation treatment is 20 to 80 ℃, and the pH of the raw material mixture is 6.5 to 8.5.
6. The method according to claim 1, wherein the temperature of the aging treatment is 65 to 95 degrees centigrade, and the time of the aging treatment is 1 to 100 hours.
7. The method of claim 1, further comprising, prior to the calcining treatment:
carrying out washing sodium removal treatment on the precipitate, wherein the washing sodium removal treatment is realized by the following steps:
and (2) washing the precipitate for multiple times by adopting an ammonia water solution with the pH value of 8.0-10.0, wherein the solid-to-liquid ratio of the ammonia water solution to the precipitate is (9-15): 1, the washing temperature is 60-95 ℃, and the washing time is 10-60 minutes.
8. The method according to claim 1, wherein the temperature of the calcination treatment is not lower than 800 ℃, and the time of the calcination treatment is 1.5 to 4 hours.
9. The method of claim 1, wherein the comminution process is a jet comminution process.
10. A catalyst support prepared by the method of any one of claims 1 to 9.
11. The catalyst carrier of claim 10, wherein γ -Al in the catalyst carrier is at a calcination temperature of not less than 800 degrees celsius2O3The content is not less than 50 wt%.
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