JPS6261637A - Preparation of activated alumina carrier having high pore void volume - Google Patents

Abstract

PURPOSE:To easily form desired fine pore distribution, by granulating hydraulic alumina, obtained by treating aluminum hydroxide having specific particle size distribution and a specific average particle size in a hot air stream at specific temp., while water is sprayed to said alumina. CONSTITUTION:Aluminum hydroxide wherein the content of particles with a particle size of 5mum or less is 80% or more and an average particle size is 0.5-5mum is thrown in a hot air stream with temp. of 400-1,200 deg.C for 0.1-10sec to form hydraulic alumina. This hydraulic alumina is granulated while water is sprayed to prepare an activated alumina carrier wherein an entire void volume is 0.5-1.5cc/g and the volume of a pore size of 1,000-10,000Angstrom is 0.2-0.6cc/g. In the aforementioned method, for example, when granulation is performed by a pan type granulator, a powder is fine and filling property becomes inferior and, therefore, the filling density of the carrier can be regulated by the spray amount of water.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention is applicable to catalyst carriers for purifying automobile exhaust gas, catalyst carriers for pollution prevention such as deodorization and denitrification, and hydrogenation and desulfurization of heavy oil. , relates to a method for producing an activated alumina carrier having a high pore volume useful as a catalyst carrier for demetalization.

[Conventional technology]

In recent years, properties required for activated alumina supports include having a controlled pore distribution and high pore volume. The reason for this is that the pore distribution of activated alumina carriers is originally concentrated in areas with pore diameters of several hundred square meters or less, which results in insufficient diffusion within the pores and is susceptible to poisoning. Therefore, there is a demand for an alumina carrier having a larger pore diameter, and it is said that in particular, a carrier having a large pore volume with a pore diameter of 1,000 to 10,000× is easy to diffuse and is difficult to be poisoned.

Normally, the average particle size obtained industrially by the Bayer method is 10 to 5.
0 micron aluminum hydroxide, 400-1200
The carrier was rapidly dehydrated at ℃ to obtain hydraulic alumina, which was then granulated into spherical shapes using a spherical granulator while spraying water. Most of the pore diameter is 2001 or less, and the pore diameter is 1000 to 1000.
The volume of 0 Å is extremely small. Therefore, there is a method to control the pore volume and distribution in the gaps between the primary particles by adjusting the amount of water sprayed during granulation using a Nomonban granulator, but with an average particle size in this range, the filling of the powder is difficult. Because it is good.

The volume of pores fi1000-10000X does not increase at), and the volume of pores with a diameter of 10000X or more increases only slightly.

In addition to the above, as a method for obtaining a carrier with a high pore volume, organic polymers such as 4-livinyl alcohol and methylcellulose, and combustible substances such as cornstarch and carnoblack are added to the alumina carrier and removed by combustion. Many methods have been reported.

[Problem that the invention seeks to solve]

In the above-mentioned prior art, if a combustible substance is added to alumina, and if an attempt is made to obtain a support with a high pore volume and a desired pore distribution, the cost of the material increases. In addition, in order to prevent the pore distribution from shifting to a larger one than the desired one, and to prevent a decrease in mechanical strength, the type and amount of combustible material added, as well as the particle size, are adjusted.
The manufacturing process is complicated, as it must be uniformly dispersed in the alumina, and it is also expensive. Furthermore, when removing combustibles, heat may be generated and the alumina may transform and become inactive.

[Ninth way to solve the problem]

This invention makes it possible to produce a high pore volume activated alumina carrier having a desired pore distribution without adding combustible materials as in the prior art, compared to the conventional average particle size of 10 to 5.
The particles are made finer than 0 microns, the particle size of 80- or more particles is smaller than 5 microns, and the average particle size is 0.5 to 0.5 microns.
By setting the pore size to 5 microns, the pore diameter is 1000 to 1o.
It has been found that the volume of oooX can be easily increased.

Therefore, in the method for producing an activated alumina carrier having a high pore volume according to the present invention, the hydroxide alumina carrier as the raw material shown above is heated in a hot air stream at 400 to 1200°C.
By adding water for 0 seconds to obtain hydraulic alumina and granulating it while spraying water, the total pore volume is 0.5 to 1.
．． 5C9f, of which pore size is 1000-1000
The method is characterized in that an activated alumina support having an 0X volume of 0.2 to 0.6 eC/7 is produced.

Note that if the temperature is less than 400°C, moisture removal from aluminum hydroxide will be insufficient and hydraulic properties will also be lost. Also 12
If the temperature exceeds 00C or exceeds 10 seconds, the crystal form of alumina will change and it will no longer have hydraulic properties.

[Effect]

In the method of this invention, when granulating hydraulic alumina with a granulator such as a pan-type granulator while spraying water, the powder is fine and the filling properties are poor. The packing density of the carrier can be adjusted by adjusting the amount of water.
The volume can be increased by 10000X.

〔Example〕

Example 1 Aluminum hydroxide obtained industrially by Bayer method,
A powder in which 85% of the particles had a particle size smaller than 5 microns and an average particle size of 2 microns was suspended in a hot air stream at 1000° C. for 2 seconds to obtain a hydraulic alumina powder.

This powder was granulated into spheres using a pan-type granulator while spraying water for 120 seconds to obtain an alumina carrier having an average diameter of 5. This was rehydrated in saturated steam at 50°C for 12 hours, and
Hydrothermal treatment was performed at 0°C.9. Thereafter, it was thoroughly dried at 120°C and fired at 600°C for 3 hours to obtain activated alumina carrier A.

The physical properties of the obtained carrier A were measured and the results are shown in the table below. In addition, the pore distribution of carrier A was measured, and the results are shown in the figure as a pore distribution diagram.

Example 2 Hydraulic alumina powder was obtained in the same manner as in Example 1 using the same aluminum hydroxide as in Example 1. This powder was granulated into spheres using a Nononya granulator while spraying water for 60 seconds to obtain an alumina carrier having an average particle size of 5 .mu.m. Thereafter, activated alumina carrier B was obtained in the same manner as in Example 1.

The physical properties of the obtained carrier B were measured and the results are shown in the table below. In addition, the pore distribution of carrier B was measured, and the results are shown in the figure as a pore distribution diagram.

Comparative Example 1 Aluminum hydroxide obtained industrially by Bayer method,
Hydraulic alumina was obtained in the same manner as in Example 1 from a powder in which 40% of the particles had a particle size smaller than 5 microns and the average particle size was 15 microns, and activated alumina carrier C was obtained in the same manner as in Example 1. Get it.

The properties of the obtained carrier C were measured and the results are shown in the table below. In addition, the pore distribution of carrier C was measured, and the results are shown in the figure as a pore distribution diagram.

Comparative Example 2 The same aluminum hydroxide as in Comparative Example 1 was used to obtain hydraulic alumina powder. An activated alumina carrier was obtained from this powder in the same manner as in Example 2.

The properties of the obtained carrier were measured and the results are shown in the table below. The pore distribution of the TW carrier was determined and the results are shown in the figure as a pore distribution diagram.

Comparative Example 3 The same hydraulic alumina powder as in Example 1 was used, and the powder was mixed in an amount of 90% by weight and cornstarch having an average particle size of 10 microns was mixed in an amount of 10% by weight. Activated alumina carrier E was obtained from this mixed powder in the same manner as in Example 1.

The results are shown in Figure 9 as a pore distribution map.

A poisoning durability test was carried out by supporting platinum at 1.0 II/A on carriers A-E, which were better than the poisoning durability test, and catalyzing them.

The durability test conditions were as follows: A converter capable of filling 1 sample of catalyst (40 d) was concentrically connected to a 1600 CC 4-cylinder engine, and the catalyst bed temperature was set at 700 to 800°C. The fuel was commercially available unleaded gasoline with the addition of tricresyl fluoride, and P O,0311/U, S, gallon, pbO,oIII/U, S, gallon of P and pb.
Containing gasoline was used. A 30-hour resistance test was conducted under the above conditions.

1000 ppm of the above catalyst), C3H6500 ppme,
C3H42000ppmo, C02, H20 10 each
1. The col1023 residue was prepared by using a synthesis gas consisting of N2 gas at a catalyst input gas temperature of 50°C and a space velocity of 30. OQ O
The purification rate was measured by flowing at hr, and the results are shown in Table 2.

Table 2 @HC and CO are each hydrocarbon and carbon monoxide.

〔Effect of the invention〕

1st! ! As shown in , according to the production method of the present invention, it is possible to obtain an activated alumina carrier with a high pore volume in which the pore diameter is 1000 to 10000 mm and the volume is in the range of 0.2 to 0.6 cc/II. Since the activated alumina support obtained by the method of the present invention has a large pore volume, diffusion within the pores is sufficient and it is not easily poisoned as shown in Table 2.

[Brief explanation of drawings]

The figure is an O pore distribution diagram for an activated alumina support having a high pore volume obtained by the manufacturing and processing method of the present invention. Out Mm Patent attorney Takehiko Kinko #11-1Lτ艷 (in)

Claims (1)

[Claims] Particles with a particle size smaller than 5 microns account for more than 80%,
Aluminum hydroxide with an average particle size of 0.5 to 5 microns is poured into a hot air stream at 400 to 1200°C for 0.1 to 10 seconds to obtain hydraulic alumina, which is then granulated while spraying water. By doing so, the total pore volume is 0.5 to 1.5
cc/g, of which the pore size is 1000-10000
A method for producing an activated alumina carrier having a high pore volume, the method comprising producing an activated alumina carrier having a volume of 0.2 to 0.6 cc/g.