JPH07121358B2 - Method for producing fluidized catalysts based on alumina - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method for producing a fluidized catalyst in which a metal component is supported on an alumina carrier.

The fluidized bed reaction has a high reaction rate due to high gas-solid contact efficiency, and has advantages such as easy removal or supply of heat in reactions involving exothermic or endothermic reactions. Has been.

<Problems to be Solved by the Invention> When the catalyst particles in the fluidized bed reaction are pulverized by collision between the particles and the vessel wall of the apparatus, the pressure loss of the catalyst layer increases,
Especially, it is required to have excellent wear resistance, since it causes deterioration of fluidity due to the particle size distribution and scattering of the catalyst.

Accurate measurement of wear resistance is difficult, and because the required wear resistance strength varies depending on the operating conditions, it cannot be said unequivocally.
It is preferable that the wear loss by the measuring method described below does not exceed 10%, and more preferably 5% or less.

The mechanical strength of the catalyst depends to a large extent on the pore structure, which also has a large effect on the catalyst activity.

The pore structure is characterized by the pore diameter and pore volume, and its function is not simple, but generally, the smaller the pore volume, the better the strength but the lower activity, and conversely, the larger the pore volume, the higher the activity. However, there is a tendency for the strength to be inferior, and the requirements of the two are usually contradictory. Therefore, it is necessary to harmonize the two in catalyst production.

<Means for Solving Problems> The present inventors have arrived at the present invention as a result of extensive studies to solve the problems. Therefore, the gist of the present invention is to provide a method for producing a fluidized catalyst by spray-drying and firing a slurry containing alumina as a carrier component and a metal component,
Alumina sol was added to and mixed with the slurry prior to spray drying, and then the average particle size of the slurry particles was adjusted to 0.
The present invention provides a fluidized catalyst having a fine pore size of 6 μm or less, which is characterized in that it is finely pulverized, and has excellent wear resistance and an appropriate pore volume.

To explain the present invention in more detail, the carrier component alumina is preferably γ-alumina, but may be a commercially available product or a product obtained by firing pseudo-boehmite gel at 600 to 1000 ° C. This γ-alumina is mixed with water to form an aqueous slurry of 5 to 60 wt%, preferably 10 to 40 wt%, and then mixed with a raw material compound such as cobalt, manganese, or ruthenium which is a metal component.

The raw material compound of the metal component may be any soluble compound, but a nitrate is preferable in terms of economy and easiness of handling, and is generally used as an aqueous solution. The amount of the metal component supported depends on the purpose of use of the catalyst.

Next, an alkali-containing solution is added to the above-mentioned alumina slurry containing the metal component to deposit the metal component as a sparingly soluble hydroxide on the carrier, and the like. When nitrate is present in the slurry, it is preferably washed with an alkali-containing solution, and nitrate or alkali metal is removed by filtration or decantation.

The obtained overcake is mixed with water to form a slurry of 5 to 60 wt%, preferably 10 to 30 wt% again.

Then, the alumina sol was used as AI ₂ O ₃ and the carrier component γ
After adding 1 to 7 wt%, preferably 2 to 5 wt% to alumina, it is finely pulverized by a wet method until the average particle diameter of slurry particles becomes 0.6 μm or less, preferably 0.5 μm or less.

The alumina sol used here is not particularly limited and may be a commercially available product.

If no alumina sol is added, a catalyst with excellent wear resistance cannot be obtained unless it is pulverized to a slurry average particle size of about 0.4 μm. Abrasion strength deteriorates extremely. Therefore, it is necessary to make it 0.3 μm or less in consideration of the fluctuation of the manufacturing conditions, but when it is carried out industrially, a great deal of energy and cost are required for fine pulverization, which is not a good idea.

Further, as the slurry particle size is reduced, the pore volume decreases linearly, leading to a decrease in catalyst activity.

On the other hand, in a system to which an appropriate amount of alumina sol was added, excellent wear resistance was exhibited at a slurry average particle size of 0.6 μm or less, and the degree of deterioration of wear resistance strength when the slurry particle size was increased was also moderate. . Furthermore, the pore volume did not decrease even if the slurry particle size was reduced to 0.3 to 0.6.
An almost constant value is obtained in the range of μm.

If the amount of alumina sol added exceeds the appropriate amount, the wear resistance is deteriorated as the pore volume increases.

Next, the finely pulverized slurry is spray-dried and then calcined at an appropriate temperature in an air atmosphere to obtain a catalyst.

Although the drying or calcination step does not affect the physical properties of the catalyst, it is the preparation process of the catalyst intermediate that is dominant for the wear resistance strength and the pore volume. It is important to finely pulverize to 0.6 μm or less.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following inventions unless the gist thereof is exceeded.

The wear resistance strength shown here is known as "Test Method for Synthetic Cracki", which is known as a test method for fluid catalytic cracking catalysts.
ng Catalysts "American Cyanamid 6/31 4m−1 /
It is the value of the wear loss obtained by the following formula, which was performed according to the method described in 57.

However, A: the weight of the catalyst that was scattered or lost due to wear for 0 to 5 hours B: the weight of the catalyst that lost due to wear for 5 to 20 hours C: the weight of the catalyst used in the test Examples-1 to 4 Obtained by calcining pseudo-boehmite gel Fine-grained γ-alumina 1
2.0 kg was added to 28.0 kg of water, and then 302 g of ruthenium nitrate aqueous solution (Ru = 18.1 g) and 9.88 kg of manganese nitrate aqueous solution (M
n = 1.51 kg), cobalt nitrate aqueous solution 17.90 kg (Co = 3.62 k
g) were added sequentially with stirring.

Then, a 10 wt% NaOH aqueous solution was added until the pH of the slurry reached 10.2 to precipitate hydroxide precipitates of ruthenium, manganese and cobalt on γ-alumina. Next, the slurry is filtered, the precipitate is washed, and then water is added again to make the total weight.
It was 97 kg of slurry. Next, divide this slurry into four equal parts,
Alumina sol (Nissan Chemical Alumina sol-200) diluted to Al ₂ O ₃ concentration of 3 wt% was 1.0 kg and 2.5 k, respectively.
g, 4.0 kg and 5.0 kg were added. The slurry added with this alumina sol was finely pulverized with a wet pulverizer to an average particle size of 0.45 μm, then spray-dried with a rotary disk type spray dryer, and the obtained dried product was calcined at 500 ° C. for 30 minutes in an air atmosphere. A catalyst was prepared.

Comparative Example-1 Fine-grained γ-alumina obtained by firing pseudo-boehmite gel 3.
Add 0 kg into 7.0 kg of water, then add ruthenium nitrate solution 74
g (Ru = 4.4g), manganese nitrate aqueous solution 2.41kg (Mn = 0.37k
g) and 4.36 kg of cobalt nitrate aqueous solution (Co = 0.88 kg) were added with stirring.

Next, a 10 wt% NaOH aqueous solution was added until the pH of the slurry reached 10.2, a hydroxide precipitate of each metal was deposited on γ-alumina, and after overwashing, water was added again to prepare a 26.1 kg slurry.

Next, this slurry was finely pulverized with a wet pulverizer to an average particle size of 0.45 μm, and then spray-dried and calcined in the same manner as in Examples 1-4 to prepare a catalyst.

Comparative Example-2 81 g (Ru = 4.9 g) of a ruthenium nitrate solution was added to a mixed slurry of the same γ-alumina 3.0 kg and water 7.0 kg used in Comparative Example-1.
After adding 2.65 kg (Mn = 0.41 kg) of manganese nitrate aqueous solution and 4.80 kg (Co = 0.97 kg) of cobalt nitrate aqueous solution, each metal hydroxide was precipitated by adjusting the pH of the slurry to 10.2 with 10 wt% NaOH aqueous solution, and then overwashed. After that, water was added again to make the total amount 18.8 kg.

Next, 10 kg of alumina sol with Al ₂ O ₃ concentration of 3 wt% was added to this slurry.
After the addition, was pulverized with a wet pulverizer to an average particle size of 0.45 μm. Then, spray drying and calcination were carried out in the same manner as in Examples-1 to 4 to obtain a catalyst. The physical properties of the catalysts obtained in Examples-1 to 4 and Comparative Examples-1 and 2 are shown in Table 1.

Examples-5 to 8 Wet a mixed slurry of ruthenium, manganese and cobalt hydroxide precipitates prepared in the same manner as in Example-2 and γ-alumina and 2.5 wt% alumina sol as Al ₂ O ₃ with respect to γ-alumina. Finely pulverized with a pulverizer to obtain an average particle size of 1.0μ
m, 0.6 μm, 0.4 μm, 0.3 μm, and then spray-dried and then calcined to obtain a catalyst.

Comparative Examples 3 to 5 A mixed slurry of ruthenium, manganese, and cobalt hydroxide precipitates and γ-alumina prepared in the same manner as in Comparative Example 1 was finely pulverized by a wet pulverizer to have an average particle diameter of 0.55 μm,
After being adjusted to 0.35 μm and 0.28 μm, spray drying and firing were performed to obtain a catalyst.

Example-2, Examples-5 to 8 and Comparative Example-1, Comparative Example-
The physical properties of the catalysts obtained in 3 to 5 are shown in (Table-2).

<Effects of the Invention> According to the present invention, it is possible to obtain an alumina carrier fluidized catalyst having sufficient activity and remarkably excellent in wear resistance.

Claims (3)

[Claims] 1. A method for producing a fluidized catalyst by spray-drying and firing a slurry containing alumina as a carrier component and a metal component, wherein an alumina sol is added to and mixed with the slurry prior to spray-drying, and then a wet grinder is used. A method for producing a fluidized catalyst, which comprises finely pulverizing slurry particles until the average particle diameter of the slurry particles becomes 0.6 μm or less. 2. The method according to claim 1, wherein the added amount of alumina sol is 1 to 7 wt% with respect to alumina as a carrier component as Al ₂ O ₃ . 3. The method according to claim 1, wherein the carrier component alumina is γ-alumina, and the metal element in the metal component is iron group metal and manganese or iron group metal, manganese and platinum group metal. Method.