DE1667079B2 - METHOD FOR MANUFACTURING SILICIC ACID - CLAY CRACKING CATALYSTS - Google Patents

Description

35

The present invention relates to a process for the manufacture of silica-alumina products which are used as Petroleum cracking catalysts are suitable.

In the catalytic cracking of hydrocarbon oils, the feedstock is heated to 430 Vaporized up to 540 ° C at overpressure. These vapors are in intimate contact with a silica-alumina catalyst brought, whereby the high-boiling components are converted into gasoline. Next to the cracking reactions take place simultaneously with various complex side reactions, such as polymerizations, Alkylations and the like take place, causing a carbonaceous precipitate on the catalyst deposited. A catalyst coked in this way has only a low cracking effectiveness, which, however, is achieved by burning off the deposit is restored from the analyzer surface under an oxidizing gas, whereupon the catalyst is returned to the cracking process. Such regeneration will usually at temperatures higher than the cracking temperatures carried out. Since the regeneration of the catalyst is exothermic, this becomes considerable Heat free.

It is known that the short life and the fto decreasing catalytic activity is due to the low heat and steam resistance of the catalyst. It is therefore essential that the catalyst be relatively heat resistant. One criterion for the catalyst stability is the surface loss after a standard steam and heat treatment. For example, a common silica-alumina cracking catalyst has a surface area of about 500 m ² / g before it is subjected to a steam and heat treatment. After the surface has initially sunk, the catalyst is in “equilibrium” and maintains this equilibrium surface as long as it is operational.

The heat resistance is particularly important in fluidized bed systems when finely divided solids Catalysts are used. Because of the extremely large turbulence required in a fluidized bed the catalyst attacked and abraded, with considerable amounts of too fine material occurring. This is difficult to keep in the system and leads to losses which are intolerable. For this reason considerable efforts are made to develop catalysts with greater mechanical strength, especially abrasion resistance, and longer service life undertaken.

In the manufacture of silica-alumina catalysts, the procedure to date has been to gel a silicate solution with a mineral acid and then add an aluminum oxide precursor to the gel or the gel-forming mixture, for example US Pat. No. 3,216,922 GB-PS 7 96 756 aluminum sulfate is added to a silica gel which has been gelled with carbon dioxide as a gelling agent. According to US Pat. No. 3,140,249, a concentrated silicate solution containing more than 40% by weight of silicate is continuously mixed with sulfuric acid and aluminum sulfate and the resulting gel is isolated. This mixing process is necessary to ensure the effective reaction of the very concentrated silicate solution with the acid and the aluminum salt solution. GB-PS 7 99 757 also describes the joint addition of sulfuric acid and aluminum sulfate.

It has now been found that a silica-alumina catalyst with a high Davison abrasion index in the range of 10 to 50 and excellent stability without the use of acid by intimate mixing with careful adjustment of the reaction ratios and reaction conditions can be established.

The invention relates to a process for the production of silica-alumina cracking catalysts, in which an aqueous, 1 to 15 wt .-% silica containing in a reaction vessel Solution, an aqueous solution containing 10 to 90 g / l of aluminum sulfate is added, the two solutions have a temperature of 21 to 66 ° C, whereupon the formed slurry of the mixture is filtered, is washed and dried, which is characterized in that the non-acidified, alkaline silicate solution and the likewise non-acidic aluminum sulfate solution with a flow rate from 0.1 to 1 volume units of aluminum sulfate solution per volume unit of silicate solution at the same time allowed to flow into the reaction kettle and the resulting slurry to a pH of 6.0 brings up to 9.0.

The catalysts prepared by the process according to the invention have surfaces which are smaller than the fresh surfaces of the catalysts prepared by other processes. Nevertheless, the product according to the invention is very much more stable to steam and heat treatment. The catalysts prepared by the process according to the invention have surface areas in the range from 250 to 350 m ² / g, but show only a very low surface loss on steam treatment.

The product manufactured using the new method also has a unique pore size distribution measured using the mercury method. Most of the mercury pore volume of the catalyst is concentrated in pores on the order of 125 to 2000 Å. It has also been found that the pore volume of the catalyst can be regulated by adjusting the temperature of the reactants accordingly, the pore volume increasing with temperature. It was also found that at room temperature the pore volume increases in inverse proportion to the Al ₂ O ₃ concentration. Another possible way of adjusting the pore volume is to change the mixing or stirring of the reaction solutions during the reaction.

A suitable silicate solution has a silica / alkali metal ratio from about 4: 1 to 1: 1 and a silica content of about 1 to 10%. Although one can use any alkali silicate, sodium silicate is preferred. After the silicate solution is prepared this heated to a temperature of preferably 24 to 38 ° C and intimately with the aluminum sulfate solution mixed, which can be easily obtained by dissolving alumina trihydrate and sulfuric acid. The solutions are prepared to contain 1 to 10, and preferably 5% alumina.

In the process of the present invention for producing silica-alumina, there are three important variables to consider: the mixing speed, the concentration of the reagents, and the reaction temperature. At the end of the experiment, the mixture is treated with ammonia in order to adjust the pH to preferably 7.5 to 9. The catalyst is filtered and washed, preferably with ammonium sulfate and / or ammonium carbonate solutions. This wash can be with ^e: ner 1 to 10% ammonium sulfate solution of 24 to 70 ° C take place. If washing is carried out with ammonium sulfate, this is usually followed by another washing with ammonium carbonate and rinsing with deionized water. The ammonium carbonate wash solution is prepared at a concentration of 1 to 10, and preferably 3 to 6%. This washing can be done at temperatures from 24 to 70 ° C and preferably between 55 and 63 ° C.

Following intimate mixing, the slurry is filtered to remove the silica-alumina ingredients to remove, and then dried, washed and dried again. This washing and drying are purely mechanical process steps and can be modified accordingly. That filtered material can be washed before drying, or the washed material can be spray dried to give silica alumina spheres or microspheres. Then will the product is finally dried at Ί 50 ° C.

A stabilized zeolite can be incorporated into the co-precipitated silica-alumina according to the invention and / or clay are incorporated so that the do catalyst consists of a silica-alumina matrix, which contains an activator or promoter. To do this, one intervenes at any point in time adjusting the pH of the slurry and before drying a rare earth aluminosilicate to and adjusts the pH to a value above 7.0 by adding ammonium hydroxide. On the other hand, can one or more of the basic or neutral solutions or slurries with a natural offset the occurring tone.

In the previously known processes, an additional ion exchange with a non-alkali Mctallion required to remove the harmful alkalis, after the aluminum silicate ir the gel mixture has been dispersed. These; naturally requires further processing times Cost and are other ways of contaminating the catalyst. The previously known procedures did not attempt to solve this problem in the present way; in particular one has, inter alia always assumed that non-alkali metals are unsuitable because they are either still undesirable Amounts of alkali ions, generally containing sodium ions, or because of an ion exchange with non-alkali ions with a metal, usually a rare earth metal, was reversible. As a result, would a large proportion of the non-alkali ketone by one Re-exchange with other undesirable cations in the process of making the catalysts get lost. Since most of these cations were rare earth metals, their loss and the result thereof required, additional repeated measure one; further ion exchange relatively expensive It has been found that the use of the so-called "stabilized" non-alkali aluminiumsi Likate to rule out a further cation exchange process step that occurs in the previously known process ren was required. This is possible without any disadvantages resulting from the previous ones Procedures using non-alkali aluminum silicates occurred. These "stabilized" non-Al Potassium aluminum silicates have a very low level Alkali content on the order of 0.3-0.4% has been found to be ineffective have to enter into a renewed ion exchange with any undesired ions that ir the solutions used in the preparation of the catalyst are available.

The stabilized non-alkali aluminum silicates, di « Can be used in the present method by the following general form represent:

χ My _n : O: AI2O3: 2 - 7 SiO ₂ : y H ₂ O

in which M denotes a Η ion or a rare earth catalyst and η is its valence, where y has a value from 0 to 9 and α · has a value from 0 to 1.

The zeolites used in the process according to the invention are given in general Formula:

A- M ₂ / ": Al ₂ O ₃ : 3.5-7 SiO ₂ : y H ₂ O
a- M ₂ ,,,: Al ₂ O ₃ : 2-3 SiO ₂ : y H ₂ O

where, with M in the second formula, a rare one; Earth metal can be included.

To produce a zeolite-activated or improved catalyst, an aqueous alkali silicate solution with 1 to 15 and preferably 5.5% by weight SiO _{2 is first} produced, which is kept at a temperature of 21 to 66 ° C and preferably 24 to 38 ° C will. An aluminum sulfate solution with an Al ₂ O3 concentration of 10 to 90 g / l depending on the amount of AbO3 desired in the catalyst matrix

by dissolving the appropriate amount of
Al ₂ (SO ₄ J ₃ - 18H ₂ O

made in water

These two solutions are then mixed in a suitable mixing vessel by adding the two solutions together, in an inflow ratio of about 0.10 to I ₁ C and preferably 0.25 volume of aluminum sulfate solution per minute per volume of silicate solution per minute. An intimate mixture with gel-like properties forms immediately when the solutions are mixed. The mixed solutions are then tumbled for about 15 minutes; these solutions, which are now a slurry, have a pH value of 3.0 to 4.5 depending on the type of alkali silicate solution used and the concentration of the aluminum sulfate solution.

After agitation of the slurry, the pH will pass above 7.0 and preferably to 7.1 to 8.0 Addition of a 14% ammonium hydroxide solution adjusted. At this point, if necessary a sufficient amount of stabilized aluminum silicate with no alkali added to the desired To achieve concentration in the catalyst. The slurry is then aged to full Ensure distribution of the aluminum silicate.

The addition of the stabilized aluminum silicate generally results in a drop in the pH value of the Slurry. Then sufficient 14% ammonium hydroxide is added to the Adjust the solution to the same pH value that prevailed before the stabilized aluminum silicate was added, d. H. to a value of over 7.0. The slurry is then filtered and re-slurried with water, until it has a solids content of 5 to 20%. The slurry is then spray dried and the solid catalyst obtained is washed. The washing can be done through several washes and multiple filtering of the catalyst with dilute ammonium sulfate solution, preferably with a 4% by weight solution, followed by a second washing process with an ammonia solution, This is followed, preferably with a pH of 9.0, followed by a final wash with water. The catalyst is filtered off after each washing and dried after the last filtering, preferably at 205 ° C.

When carrying out the process according to the invention for producing a clay-activated catalyst, an aqueous alkali metal silicate solution with a content of 1 to 15 and preferably 5.5% by weight of SiO _{2 is first} produced. A naturally occurring clay is added to this solution in the desired amount, preferably from 30 to 70%. Preferably a kaolin clay is used; however, other naturally occurring clays can also be used. An aluminum sulfate solution is then prepared by dissolving hydrated aluminum sulfate in enough water to obtain 10 to 90 and preferably 30 to 70 g / l Al2O3. This solution and the silicate solution are then continuously pumped into a mixing chamber. The silicate solution is usually pumped in at a rate of 1 to 10 volumes per minute per volume of aluminum sulfate solution. The temperature of the solution should be between 21 and 65 ° C and preferably between 24 and 38 ° C. It has been found that the pore volume can be easily regulated by changing or adjusting the temperature and concentration of the reaction solutions within the ranges given above.

When the solutions are mixed, an intimate mixture of silica-alumina is formed almost immediately. That jointly precipitated silica-alumina precipitate in which the clay particles are now within the matrix is dispersed sinti, and the solutions are further mixed together and by agitation aged, although other mixing methods are also used

Formation of the slurry can be used.

The slurry is then made up with ammonia

a pH greater than 7 and preferably in

a range from 7 to 9. The slurry is filtered and re-slurried with water, so that the solids content is 10 to 20%. The reslurried mixture is spray dried. That Spray drying and washing can of course be modified; a good drying and washing process is explained in more detail in Example 12 below.

The process described above can be modified in the essential process steps. For example The clay can be added after the aluminum sulfate solution and the silicate solution with each other have been mixed; the process can be carried out either batchwise or continuously or a combination of continuous and intermittent work can be used will.

The products prepared by the process of the invention and activated with zeolite and clay have a significantly improved initial activity compared to the non-activated silica-alumina catalysts; at the same time, they retain the thermal stability and vapor stability of the non-activated ones intimate catalyst mixtures.

Eventually it was found that by using a combination of naturally occurring clay and aluminum silicate an excellent catalyst is obtained. The exact reason for this effect is not known; however, it is believed that the clay serves as a matrix for the aluminum silicate and the Promotion of implementation not only on the active zeolite areas, but also on the matrix itself relieved.

The stabilized non-alkali aluminosilicate to be used with clay is already the one above mentioned product, which can also be used on its own.

When carrying out this part of the process according to the invention, an aqueous alkali metal silicate solution containing _{1 to 15 and preferably 5.5% SiO 2 is first prepared.} Enough naturally occurring clay is added to this solution to achieve the desired amount in the catalyst. The clay can be added to any basic or neutral solution or slurry prior to spray drying, although it is preferred to add the clay before the aluminosilicate. Kaolin is the preferred clay, although other naturally occurring clays can also be used.

After that, an aluminum sulfate solution is made by mixing hydrated aluminum sulfate in enough Dissolves water to obtain a solution of 10 to 90 and preferably 30 to 70 g / l. This solution and the silicate solution are then continuously pumped into a mixing chamber. The silicon solution is with at a rate of 1 to 10 volumes ie minute

pumped in per volume of aluminum sulfate solution. The temperature of the solution should be between 21 and 66 ° C and preferably between 24 and 38 ° C. It was found that the pore volume and the surface area by changing or adjusting the temperature and concentration of the reaction solutions within of the range specified above can be regulated.

When the solutions are mixed, an intimate mixture of silica-alumina is formed almost immediately. This intimate mixture of silica-alumina, in which the clay particles are now dispersed in their matrix and the solutions are mixed together and aged by agitation, although different Mixing techniques can be used to form the slurry.

The slurry is then adjusted to pH with sufficiently dilute ammonium hydroxide greater than 7.0 and usually in the range of 7.0 to 8.0. The slurry usually has Depending on the amounts of silicate and aluminum sulfate solution present, a pH of 3.3 to 5.0. Sufficient stabilized aluminum silicate is added to this solution to achieve the desired percentage in the end product. Although it is preferred that the stabilized aluminosilicate be used in this step is added, it can also be added to any nearly neutral or basic solution or slurry including added to the original silicate solution prior to spray drying. The slurry will then aged and diluted sufficiently with ammonium hydroxide to keep the pH of the slurry that normally drops below 7, then set back to 7 and usually between 7 and 8 can.

The slurry is then filtered and washed and dried as described above. Suitable Washing and drying processes are also illustrated in the following examples.

The silica-alumina catalyst according to the invention or the matrix of the activated catalyst according to the invention can be referred to as a hydrocarbon cracking catalyst based on silica-alumina with a low surface area, consisting essentially of an intimate silica-alumina mixture with a surface area of 250 up to 350 m ² / g and a Davison abrasion index of 10 to 50.

The invention will be explained in more detail below with the aid of examples.

example 1

This example illustrates a continuous process for producing a 13% Al2O3 in intimate Mixture-containing catalyst according to the invention, wherein at a reaction temperature of 26.1 ° C is being worked on.

There was prepared an aluminum sulfate solution by 3075 g of analytically pure 105% Al ₂ (SO ₄ J _3-18 H ₂ O dissolved in enough water to obtain 14.21 solution Then, a 5 by dissolving a suitable amount of sodium silicate in water. , 5% SiO prepared _2-containing silicate solution. The. silicate solution was pumped at a temperature of 26.1 ° C at a rate of 3.8 liters per minute into a mixing chamber, the sulfate solution held at 233 ° C at a rate of 0351 per These two solutions were pumped into the mixing chamber for a total of 133 minutes. When these two solutions came into contact with one another, the catalyst mixture formed. The solutions, which were now in the form of a slurry, were then aged by circulating for 15 minutes 0.98 liters of 14% ammonium hydroxide solution was added to raise the pH from 3.8 to 8.1 and this slurry was added de then aged another 5 minutes. The filtered product was reslurried with water, the strength content being 8.8%; this material was then spray-dried, the container pressure being 3.5 kg / cm ² , the spray pressure 2.5 kg / cm ² , the inlet temperature 315 ° C. and the outlet temperature 107 ° C.

The catalyst was then washed, one ml of washing solution being used per cubic centimeter of catalyst, namely with a three-fold two-liter wash with a 14% ammonium sulfate solution at 60 ° C and a subsequent three wash with 2 liters of a 5% strength ammonium carbonate solution at 6O ⁰ C. the mixture was then dried, the catalyst was washed twice with 2 liters of water at 6O ⁰ C and then 4 hours at 205 ⁰ C.

Example 2

The procedure was analogous to Example 1, except that the reaction temperature was 38.degree.

The same aluminum sulfate solutions, with a concentration of 34.8 g Al2O3 per liter, and Silicate solutions, this time at a temperature of 39 ° C, combined, and 14 minutes and 15 seconds pumped together, again circulated for 15 minutes, with 850 ml of a 14% ammonium hydroxide solution treated to bring the pH from 4.15 to 7.9, whereupon the slurry is filtered and the Filter cake was reslurried with water to a solids content of 10.2%. This slurry was then also spray-dried, washed and dried as in Example 1.

Example 3

The following example shows a continuous process for the preparation of an _{intimate catalyst mixture according to the invention containing 25% Al 2} O ₃ , with reaction temperatures of 23.9 ° C being used.

There were 6805 g of analytically pure 105%

Al ₂ (SO-O _3-18 H ₂ O

dissolved in water to produce a solution of 28.5 liters with a concentration of 38.6 g Al ₂ O ₃ per liter. A silicate solution containing 5.5% SiO ₂ at a temperature of 23.9 ° C. was pumped into a mixing chamber at a rate of 3.8 liters per minute .9 liters per minute pumped into the mixing chamber. When these two solutions came into contact, an intimate mixture was formed. These solutions were pumped together for 15 minutes, after which the resulting slurry was aged by agitation for 15 minutes. Then 5.6 liters of 14% Na ₄ OH were added to raise the pH from 3.6 to 7.05. The slurry was then filtered and the filter cake was slurried again with water so that the product obtained had a solids content of 9.0%. This repeated slurry was then spray-dried, washed

609550/437

¥

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see and dry as described in Example 1 is.

Example 4

The procedure was analogous to Example 3, but the reaction now took place at 38.degree. The silicate solution was brought into the mixing chamber at a temperature of 38 ° C and the aluminum sulfate solution at a temperature of 39 ° C, which took 14 minutes and 45 seconds. Otherwise, the procedure was exactly as in Example 3, the suspension being brought from a pH of 3.9 to 7.3 _{with 5.3 liters of a 14% NH 4 OH solution.} The reslurried filter cake had a solids content of 9.6%.

In the case of the products of these four examples, the pore volumes and the surfaces were determined after calcination for three hours at 540 ^° C. according to the customary Brunauer-Emmett-Teller method using nitrogen. The abrasion index according to Da ν i so η was determined by treating the catalyst to be examined in a strong jet of air and determining the weight of the -20 micron particles formed. This test was carried out for 5 hours, weighing after 30 minutes, after one hour and then at hourly intervals until the total test time of 5 hours had elapsed. The Davison abrasion index is then determined according to the following equation:

Davison abrasion index =

100 (A - B)

where / 4 = the content of the catalyst after abrasion of parts ranging in size from 0 to 20 microns, including any fines collected during the abrasion test; B = the level of particles in the catalyst prior to attrition of 0-20 microns in size ; and C = the level of the catalyst's level of particles larger than 20 microns measured prior to attrition.

The results of these experiments and the chemical composition of the reaction products from the Examples 1 to 4 are given in the following table:

Table 1

Examples 2 3 4th 1 38.0 23.9 38.0 Reaction temp. in ° C 26.1 Wt% of 13.9 24.4 25.0 A12Ü3 13.9 _ 18.1 24.6 Reactive clay 8.5 0.001 0.02 0.01 NazO 0.02 0.04 0.21 0.09 SO4 0.04 276 141 193 Surface in m ² / g 261 0.78 0.82 Pore volume, g / ml 0.66 32.3 43.6 45.5 Abrasion index 20.4

The above table shows that the silica-alumina catalysts according to the invention have both a low surface area and good abrasion resistance and consequently a considerable improvement over the known silica-alumina catalysts represent with low surface.

Example 5

This example shows the production of a silica-alumina catalyst, the mixing temperature in the present case being 23.9 ° C. and the catalyst produced containing 13% by weight of Al ₂ O ₃ matrix and 5% by weight of a rare earth aluminum silicate (SE = rare earths) with a silica / alumina ratio of 2: 3.

ίο 3075 g of analytically pure AI ₂ (SO ₄ ^ ■ 18 H ₂ C were dissolved in enough water to produce a 14.2 liter _{solution with an Al 2} O ₃ content of 34.8 g per liter. This solution was at 23.9 ° C and at a rate of 0.95 liters per minute together with a _{sodium silicate solution containing 5.5% by weight SiO 2} at 23.9 ° C at a rate of 3.8 liters per minute into a mixing chamber to be intimately mixed in 13.5 minutes, and the resulting slurry was then added

aged by agitation for 15 minutes. The pH was adjusted from 4.15 to 8.4 by adding 600 ml of a 14% NH _{4 OH solution.} At this point 258 grams of the aluminum silicate was added, the pH dropping to 8.15.

The slurry was then filtered and reslurried to have 9.3% solids Form product. This slurry was then at a tank pressure of 3.5 atm and one Spray pressure of 2.5 atm with an inlet temperature of 315 ° C and an outlet temperature of 105 ° C sprayed.

The catalyst was then washed keeping the wash volume to the catalyst volume at a value of 2; it was washed five times with 4 liters of a 4% ammonium sulfate solution of 60 ° C and then three times with 4 liters of an ammonia solution having a pH of 9 at 60 ° C and then washed once with 4 liters of water at 6O ⁰ C, wherein after each wash was filtered. The catalyst was

then dried in an oven at 205 ° C for 4 hours.

Example 6 Catalyst activated with zeolite

The catalyst prepared according to this example had a 13% by weight Al ₂ O ₃ matrix and contained 7% by weight rare earth aluminum silicates with a silica / alumina ratio of more than 3: 7. The precipitation temperature was 23.9 ° C .

The aluminum sulfate solution and the silicate solution were together for 14.25 minutes as in Example 1 mixed. After aging, 1.05 liters of a 14% ammonia solution was added to adjust the pH from 4.0 to 7.75. Then 278 g of the

Aluminum silicate was added, whereupon 50 ml of a 14% NH ₄ OH solution was added in order to bring the pH from 7.0 to 7.5. The slurry was then filtered and reslurried with water until the solids content was 11%

fraud. This reslurried product was then spray dried, washed and dried as is it is described in Example 5.

Example 7 Zeolite activated catalyst

For the production of a catalyst with a 13% by weight AIzOrMatrix and a content of

f

25th

7.3% by weight of S.E. aliminium silicate with a silica / alumina ratio of 2: 3 at a common precipitation temperature of 38 ° C, the aluminum sulfate and silicate solutions mixed with one another for 15 minutes and aged as in Example 1, but with the temperature of the silicate solution was now 38 ° C and that of the aluminum sulfate solution was 39 ° C. After aging 900 ml of a 14% ammonia solution were added, to bring the pH of the slurry from 4.2 to 8.2. Then 442 g of aluminum silicate and then 60 ml of a 14% ammonia solution were added to bring the pH from 6.6 to 7.85 to adjust. The slurry was then filtered, reslurried with water to make a Solids content of 12.1% was obtained. This reslurried product was then spray dried, washed and dried as in example 5.

Example 8
Catalyst activated with zeolite

The catalyst produced according to this example had a 25% Al ₂ O ₃ matrix and contained 7% by weight rare earth aluminum silicates with a silica / alumina ratio of more than 3: 7. The precipitation temperature was 26.1 ° C.

There were 6805 g of an analytically pure

Al ₂ (SO ₄ J ₃ · 18H ₂ O

dissolved in water and prepared 14.2 liters of a solution which contained 77.1 g of Al ₂ O ₃ per liter. The solution was then mixed for 15 minutes and aged as in Example 1. After aging, 5.6 liters of a 14% ammonia solution was added to raise the pH from 3.5 to 7.6. Then 342 grams of the aluminum silicate was added and the slurry aged for 5 minutes. Then 200 ml of a 14% ammonia solution were added in order to bring the pH to 7.65. The slurry was then filtered and reslurried until it was 11.7% solids. The reslurried product was then spray dried, washed and dried as in Example 5.

Example 9

The catalyst produced according to this example had a 25% Al ₂ O3 matrix and contained 7% by weight rare earth aluminum silicates with a silica / alumina ratio of 2: 3. The co-precipitation was carried out at 23.9 ⁰ C. The aluminum sulphate prepared as in Examples umd silicic acid solutions were prepared according to Example 8 are mixed and aged, and then with 5.6 liters of ^e; 14% ammonia solution was added to bring the pH value from 3.5 to 7.4. Then 490 g of the aluminum silicate were added, whereupon the pH value of 6.9 with 300 ml

Table 3

a 14% ammonia solution was brought to 7.5. The slurry was filtered, again Slurried, spray dried, washed and dried as in Example 8.

It is noted that the specification of the aluminum silicate in% by weight in the catalyst is determined by multiplying the Al2O3: SiO ₂ content of the aluminum silicate (and not the total weight of the aluminum silicate) by 100 and then dividing by the total weight of the catalyst.

The corresponding surface areas and pore volumes of the catalysts according to the examples were calcined for three hours at 538 ° C. using the customary Brunauer-Emmett-Teller method determined with nitrogen. The results are summarized in the following table:

45

Tabel 2 % AI2O3- Reaction surfaces Pores Ex. matrix temperature area volume No. in ⁰ C in m ² / g in g / ml 13th 23.9 258 0.47 5 13th 23.9 142 0.34 6th 13th 37.8 358 0.61 7th 25th 23.9 212 0.89 8th 25th 23.9 256 0.93 9

30th

Examples 7 and 9 were selected as typical examples of such catalysts and the following tests were carried out on the products of these examples, comparative tests being carried out with customary, non-activated silica-alumina catalysts with a large surface area in which the Al ₂ O ₃ gel was carried out 25 to 30 <y>.

Comparative experiment 1
Deactivation by steam treatment

The samples were exposed to 100% water vapor at 675 ° C. for 20 hours, whereupon a further steam treatment with 20% steam and 80% air at 827 ° C followed.

Comparative experiment 2

There were determined the cracking properties of the catalysts according to the steam activation with 20% steam at 827 ⁰ C and compared with conventional a silica / alumina catalyst type, 25 to 30% and preferably 27% alumina contained.

The experiments were carried out in a fluidized bed cracking plant with Texas heavy gas oil, the ratio of catalyst to oil used being 4.0. The plant was carried out at 493 ^° C. with a throughput rate of 10 without circulation. The results of these comparative tests are shown in Tables 3 and 4 below.

Catalyst type S12O3 / AI2O3

Example 7 Example 9

At 664 ° C 100% steam
Surface in m ² / g
Pore volume, ml / g

At 827 ° C 20% steam
Surface in m ² / g
Pore volume, ml / g

300 0.6

140 0.47 155
0.38

79
0.25

127
0.30

79
0.18

Table 4
Crack activity

Catalyst type
SLO3 / AI2O3

Example 7 Example 9

Conversion in% by volume
Wt% hydrogen
Vol .-% Cs + gasoline
Wt% coke

From these tables it can be seen that the catalysts according to the example in spite of a smaller surface and pore volume both before and after steam deactivation compared to usual strong Alumina-containing silica / alumina catalysts have higher conversion and higher volume conversion of crude oil into the desired C5 and gasoline product without the undesired Coke deposit increases. This clearly shows the essential improvement over the previous ones known high alumina catalysts.

Example 10
(Clay activated catalyst)

This example shows a batch process according to the invention. 10 140 g of an “N-brand” sodium silicate with an SiO ₂ content of 28% were dissolved with water to form a _{solution containing 5.5% SiO 2} , to which 2910 kaolin clay were added. An aluminum sulfate solution was prepared which contained 3220 g of analytically pure Al ₂ (SOi) ₃ · 18 H ₂ O and 50 l of water. This solution was slowly added to the silicate / clay mixture until this mixture gelled. The reaction temperature was 39 ° C. The slurry was then aged for 15 minutes and the remainder of the aluminum sulfate solution added. This mixture was then adjusted to pH 9 with dilute ammonium hydroxide. The slurry was then filtered, reslurried, and spray dried. The catalyst was then freed from soluble salts by washing and treated at 205 ° C. for 3 hours. The catalyst obtained according to this example had a 13% Al ₂ O ₃ matrix and contained 40% kaolin clay.

Example 11
(Clay activated catalyst)

This process was carried out as in Example 10, but now 7200 g Al ₂ (SO ^ ₃ · 18 H2O were used, which was sufficient to obtain a 25% Al2O3 matrix. The clay content was again 40% by weight.

Example 12
(Clay activated catalyst)

This example relates to a continuous process according to the invention. There was a sodium silicate solution with 5.5% SiO ₂ prepared containing kaolin clay contained This solution was ₂ O ₃ each contained together with an aluminum sulfate solution containing 34.8 g Al liter, placed in a container with a capacity of 1 gallon, which has a had a high speed stirrer. The solutions were pumped in at 38 ° C and formed an intimate mixture when combined. This slurry was then

52.0 59.0 60.5 0.040 0.051 0.047 44.5 51.0 51.5 3.0 2.6 3.0

Aged for 15 minutes by circulating or pumping over and adjusted to a pH of 7.7 with dilute ammonium hydroxide. The slurry was then filtered, reslurried and then spray-dried. The spray drying took place at an inlet temperature of 315 ° C. and an outlet temperature of 108 ° C., a container pressure of 3.5 kg / cm ² and a spray pressure of 2.5 kg / cm ² . The dried catalyst was then washed when the volume of the washing liquid to that of the catalyst was 2: 1.

It was washed five times with 4% ammonium sulfate solution with a pH of 7.8 at a temperature of 54 ° C. and then three times with a dilute NH ₄ OH solution with a pH of 9 at 54 ° C., followed by washing was washed once with water at 6O ⁰ C. The catalyst was filtered after each wash. After the last wash with water, the catalyst was ^{dried at 205 °} C. for 3 hours. The catalyst obtained according to this example had a 25% Al ₂ O ₃ matrix and contained 40% by weight of kaolin.

Example 13

_J5 (Sound Activated Catalyst)

The procedure was analogous to Example 11, except that the solutions were mixed at 27.8 ° C. and the Al ₂ O ₃ concentration of the aluminum sulfate _{solution was 72.4 g of Al 2} O ₃ per liter. The surface area, the pore volume and the microactivity calculated in% by volume of the converted products were then determined after calcining at 538 ° C. for three hours.

The surface and the pore volume were determined according to Brunauer-Emmett-Teller using stick

fabric determined. When determining microactivity, a small sample of West Texas gas oil was found with a syringe into a glass reactor, which is a small sample of the catalyst to be examined contained. The glass reactor was kept at a temperature of 482 ° C. during this process. The reaction products were then examined quantitatively and qualitatively in the usual way and the conversion in vol .-% certainly. The results are shown in Table 5 below.

Table 5

example 11th 12th 13th 10 38 38 27.8 Temperature of the vice 38 set product 35 32 32 % AI2O3 28 172 176 202 surface 194 0.68 0.66 0.81 Pore volume 0.50 713 65.6 70.6 Vol-% conversion 773 22nd 16 16 Throughput speed 22nd age

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The catalyst produced according to each example contained essentially 40% by weight kaolin clay. the Table shows that the inventively produced Catalysts have an excellent initial activity despite a lower surface area. In addition, s these catalysts have extremely low coking factors.

Example 14
(Catalysts activated with zeolite and clay)

This example demonstrates a method for preparing a catalyst according to the invention containing 25% AI ₂ O _3, 33% kaolin and 7 wt .-% (based on the AbOj: SiO2 content of the aluminum silicate) a stabilized Aiuminiumsilikats the following formula

x M ₂ / _n : Al ₂ O ₃ : 2-3 SiO ₂ : yH ₂ O

in which M is a rare earth metal cation such as yttrium and y is a value from 0 to 9 and χ is a value from 0 to 1.

A sodium silicate solution containing 5.5% by weight SiO ₂ at a temperature of 24.4 ° C. was fed into a mixing chamber at a rate of one gallon per minute together with an aluminum sulfate solution of 24.4 ° C. at a rate of 0.5 Gallons pumped per minute. The aluminum sulfate solution was obtained by dissolving 6505 g of analytically pure 105% strength

Al ₂ (SO ₄ ^ ■ 18H ₂ O

in sufficient water to make 7.5 gallons of a _{solution containing 38.6 Al 2} O ₃ per liter.

The resulting slurry was then agitated for 15 minutes. Then 5.8 l of a 14% NH ₄ OH solution were added in order to bring the pH of the slurry from 3.6 to 7.4. Then 2780 g of kaolin was added to the slurry and the slurry was divided into two parts. Part A contained all of the slurry minus two gallons, while Part B contained that two gallons of slurry. 733 g of the stabilized aluminum silicate were added to slurry A, the pH of the solution being reduced to 6.75. Then 200 ml of a 14% NH ₄ OH solution were added in order to bring the pH back to 7.4. Slurry A was then agitated for 15 minutes and then filtered. The filter cake was reslurried with water to give a 14.5% solids slurry. This slurry was then spray dried at an inlet temperature of 316 ° C, an outlet temperature of 106 ⁰ C at a tank pressure of 3.5 kg / cm ² and a Versprühdruck of 2.5 kg / cm ^2. The dried portion of sample A of about 1115 g had a volume of 2000 ml; this part was washed, the wash volume to the catalyst volume being 2: 1. It was washed five times with a 4% ammonium sulfate solution at 60 ° and a pH of 7.8, followed by three times with dilute NH ₄ OH with a pH of 9.0 at 60 ° C and then again with water at 6O ⁰ C was washed. The catalyst was filtered after each wash.

The other sample B of the slurry was treated in exactly the same way as sample A, except that 200 ml of a 14% NH ₄ OH solution were not now added. Samples A and B were dried separately at 205 ° C. for about 3 hours. Sample A corresponded to a catalyst according to the invention. Although sample B could be used as a catalyst, it did not correspond to a catalyst according to the invention.

Example 15

ίο The procedure was analogous to Example 14, except that the reaction temperature and the temperature of the silicate solution were 38 ° C. The pH of the slurries was slightly different so that only 100 ml of a 14% NH ₄ OH solution had to be added to slurry A, after which the stabilized aluminum silicate was added. The filter cake was reslurried and this slurry had a solids content of about

Example 16

The procedure was as in Example 14, except that the concentration of the aluminum sulfate solution was increased to 77.2 g Al2O3 per liter and the flow rate was reduced to 0.25 gallons per minute. The temperatures of the silicate solutions and the reaction were 27.8 ° C in this experiment. After the aluminum silicate had been added to solution A, 400 ml of 14% NH ₄ OH were added instead of 200 ml as in Example 14. The filter cake was reslurried and had a solids content of 17.2%.

Example 17

In this example a stabilized rare earth aluminum silicate with a silica / alumina ratio of more than 3: 7 was used. A sodium sulphate solution at 25 ° C. containing 5.5% by weight SiO _{2 and} containing 2780 grams of clay per 15 gallons was pumped into a mixing chamber at a rate of one gallon per minute along with an aluminum sulphate solution of 27.8 ° C pumped at a rate of 0.25 gallons per minute. The aluminum sulfate solution became analytically pure 105% by dissolving 6805 g

Al ₂ (SO ₄ I ₃ ■ 18 H ₂ O

in enough water to produce a solution containing 14.2 liters with 77.2 g of Al ₂ O ₃ per liter. The solutions were pumped through for 15 minutes and then aged and circulated for a further 15 minutes. Then 5.6 liters of a 14% NH ₄ OH solution was added to bring the pH of the slurry from 3.5 to 7.6 at which time 530 g of aluminum silicate was added. Then 200 ml of a 14% NH ₄ OH solution was added to bring the pH of the slurry to 7.5. This slurry was then filtered and reslurried to 15% solids. This slurry was then made as in Example 14

(ίο spray dried, washed and dried.

Example 18

A catalyst was prepared analogously to Example 17, but now 420 g of aluminum silicate were used. The silicate solution and the mixing temperature were 23.9 ° C. The generated The catalyst contained 5% by weight of the aluminum silicate added.

Example 19

A catalyst was produced according to Example 18, but the aluminum sulfate solution concentration was reduced to 34.8 g Al2O3 per liter in order to produce a catalyst with 13% by weight Al2O3. The silica and alumina solutions were mixed at 39 ° C. The only significant difference in the present process was that 1 liter of 14% NH ₄ OH was added before the addition of 452 g of aluminum silicate and 60 ml after this addition.

Example 20

The catalyst prepared according to this example had a aboi content of 13% and an aluminum silicate content of 7% analogously to Example 14. The reaction temperature was 26.1 ⁰ C. The procedure was substantially analogous to Example 19, except that the aluminum sulphate and silicate solutions with each other 13, 75 minutes were mixed at 26.1 ° C, and 632 ° aluminum silicate was added and then 100 ml of a 14% NH ₄ OH solution was added. The corresponding surface areas and pore volumes of the products of these examples were determined after treatment at 538 ° C. for three hours. The results are summarized in Table 6 below. For the sake of simplicity, the aluminum silicate according to example 14 is designated as type “X” and the aluminum silicate according to example 17 as type “Y”.

Table 6 example

No.

% AI2O3

Precipitation temperature
in "C

Type and% aluminum silicate surface
in m ² / g

Pore volume
ml / g

14th 25th 24.4 X, 7 189 0.62 15th 25th 38 X, 7 187 0.68 16 25th 27.8 X, 7 204 0.63 17th 25th 26.7 X, 7 221 0.81 18th 25th 23.9 X, 5 183 0.65 19th 13th 38 X, 7 188 0.69 20th 13th 26.1 X. 7 172 0.47

The kaolin content was about 33% in each example. The contents of Aluminum silicate were only made on the AI2O3 · SiOj content of the aluminum silicate determined per total catalyst weight.

The products according to the examples showed the 25% Al2O3 and 7% stabilized aluminum silicate containing products as the most suitable. Further attempts were made with the products of these examples carried out in order to determine their microactivity in the form of volume% conversion. The Activities these catalysts were then compared with conventional high-alumina catalysts.

The microactivity test consists of pouring a small amount of West Texas gas oil over a Syringe into a glass reactor kept at 427 ° C and a small sample of the to it investigating catalyst contained. The reaction products were then quantitatively and qualitatively based investigated in the usual way and calculated the conversion in% by volume. The hourly throughput rate had a value of 16. The catalyst used for comparison with a large one The alumina content was a common silica / toner <ss de-catalyst with an Al2O3 content of 25 to 30% by weight, generally 27%.

The results of this study are summarized in the following table.

Table 7

Catalyst according to Vol% example conversion 14th 75 15th 77 16 84 17th 80 Highly alumina content 63

This table shows that the catalysts prepared according to Examples 14 to 17 greatly increased one Have conversion in vol .-%, which is 12 to 21% more than the usual high alumina catalyst. This results in a considerable advantage over the previously known catalysts with only small surface.

Claims (3)

Patent claims: 1. A process for the preparation of silica / alumina cracking catalysts, in which an aqueous solution containing 10 to 90 g / l aluminum sulfate is added to an aqueous solution containing 1 to 15% by weight of silica in a reaction vessel, the two Solutions have a temperature of 21 to 66 ° C, whereupon the ι ο formed slurry of the mixture is filtered, washed and dried, characterized in that the non-acidified, alkaline silicate solution and the likewise non-acidified aluminum sulfate solution at a flow rate of 0.1 Up to 1 volume unit of aluminum sulfate solution per volume unit of silicate solution is allowed to flow simultaneously into the reaction vessel and the resulting slurry is brought to a pH of 6.0 to 9.0. 2. The method according to claim 1, characterized in that one at any time a rare earth aluminosilicate between adjusting the pH of the slurry and before drying is added and the pH is adjusted to a value above 7.0 by adding ammonium hydroxide. 3. The method according to claim 1 or 2, characterized in that one or more of the basic or neutral solutions or slurries with a naturally occurring clay offset.