DE2249022B2 - Process for the production of hydrous alumina and its use - Google Patents

Description

40

The invention relates to a process for the production of hydrous aluminum oxide and its use for the production of catalysts.

Hydrous aluminum oxide with a relatively high bulk density can be obtained by reacting Sodium aluminate and aluminum sulfate are produced. A hydrous alumina produced in this way can contain a considerable amount of bayerite contain.

It has now been found that catalysts with improved properties with respect to the hydrogenating Desulfurization can be made from hydrous aluminum oxide with a lower bulk density can.

The object of the invention was therefore to provide a water-containing aluminum oxide which consists essentially of pseudoboehmite and has a relatively low bulk density has to make available. This object is achieved by the invention

The process of the present invention for producing hydrous alumina by mixing an aqueous aluminum sulfate solution with an aq Sodium aluminate solution, separating the precipitated hydrous aluminum oxide from the reaction mixture and washing the reaction product is characterized in that an aluminum sulfate _{solution with a concentration of at least 2 percent by weight, calculated as Al 2} O ₃ , is mixed with a sodium aluminate solution up to a stoichiometric excess of 10 percent aluminum sulfate up to 10 percent sodium aluminate is added that the sodium aluminate solution is added with stirring at such a rate that at least half, preferably at least ² hours, of the hydrous aluminum oxide falls out of the reaction mixture, as long as it has a pH value in the acidic pH range, that one continues the addition of the sodium aluminate solution as long, until the reaction mixture has reached a pH value of 7.3 to 10.0, that one keeps the temperature of the reaction mixture in the range of 12 to 35 ° C or from 45 to 70 ⁰ C. that the resulting slurry of w Water-containing aluminum oxide is allowed to age in the alkaline range for a maximum of 3 hours by separating the water-containing aluminum oxide and optionally washing and / or drying and optionally calcining at temperatures in the range from 300 to 400.degree

In the process according to the invention, a slurry of the hydrous aluminum oxide is used a concentration of 2 to 7 percent by weight. The addition of the sodium aluminate solution is preferably carried out over a period of about 1 minute to 5 hours.

According to a particularly preferred procedure according to the invention, an aqueous aluminum sulfate solution with a concentration of 2 to 7.5 percent by weight, calculated as AbO ₃ , and an aqueous sodium aluminate solution with a concentration of 2 to 7 percent by weight, calculated as Al ₂ O ₃ , are used

Mixing is carried out while stirring the aluminum sulfate solution by gradually adding the sodium aluminate solution over a period of 15 minutes to 1 hour until the pH of the mixture is 73 to 10.0. Mixing is carried out so that during at least ^{2/3 of} the aforesaid The reaction mixture or the aluminum oxide slurry is kept at temperatures in the range from 12 to 35.degree. C. or from 45 to 70.degree. The resulting slurry is aged for a maximum of 2 hours. The slurry is then filtered to give a filter cake having a hydrous alumina concentration of 8 to 16 percent by weight calculated as Al ₂ O ₃ . The filter cake is expediently washed with water in an amount of at least its own volume and then expediently dried at a temperature of at most 150.degree

In order to control the concentration of the obtained hydrous alumina slurry, in the process of the invention aluminum sulfate and sodium aluminate in the by the following Equation given concentrations and proportions are used:

Weight percent Al ₂ O ₃ in the slurry = In the above equation, means A Percentage by weight of Na ₂ O in the sodium aluminate solution

solution, B percent by weight AIzO ₃ in the sodium aluminate solution sung,

C Weight percent excess sodium aluminate D Weight percent SO ₃ in the aluminum sulfate solution

and E weight percent alumina in the aluminum sulfate solution.

When aluminum sulfate is in excess, C a negative value

The water-containing aluminum oxide with a low bulk density produced according to the invention consists mainly composed of pseudo-boehmite, however, it can also contain a small amount of bayerite. The term "Pseudoboehmite" means a hydrous aluminum oxide that is identical to the first through X-ray diffraction identifiable product This product is obtained when freshly precipitated hydrous aluminum oxide together with its mother liquor is left standing. The bands of this product in the X-ray spectrum are with the exception of the 6.11-A line identical to those of crystalline boehmite. In the In this specification, the terms "boehmite" and "bayerite" are used as defined in the ASTM X-ray Diffraction Index

In the process according to the invention, pseudoboehmite with a low bulk density can be produced which contains at most 10 percent by weight of bayerite. That is, not more than 5 percent by weight, contains Byerite. Such a pseudoboehmite can have a powder bulk density of less than 0.55 g / cm ³ .

When an aqueous sodium aluminate solution is placed in an aqueous aluminum sulfate solution, assumed that initially basic aluminum sulfate is formed and that this then with further Sodium aluminate reacts, whereby hydrous aluminum oxide precipitates. This hydrous aluminum oxide is obtained in the form of a slurry which contains dissolved sodium sulfate. The hydrous aluminum oxide falls during practically the entire addition time the aqueous sodium aluminate solution.

The aluminum sulfate solution initially reacts acidic. The addition of the sodium aluminate solution increases the pH of the mixture at, and if about 70 percent or more of the stoichiometrically required amount of the sodium aluminate are incorporated, the pH of the mixture has a value of 7 or higher.

If the rate of addition of the sodium aluminate solution and the agitation of the mixture are controlled sufficiently, a substantial portion, e.g. B. 50 percent or more of the hydrous alumina before the mixture reaches a pH of 7. The sodium aluminate is preferably added in such a way that the reaction mixture ^{reacts acidic for at least 2} Ii of the addition time.

The rate of addition of the sodium aluminate solution should be controlled in this way in conjunction with the strength of the stirring force that extreme conditions in the reaction mixture that lead to products with undesirable properties can lead to be avoided. The term "gradual" addition is understood to mean that the Addition takes place in such a way that there are no extreme conditions in the Reaction mixture occur. If the rate of addition is too high in relation to the strength of the agitation, Local volumes in the reaction mixture with pH values above 7 can arise from such volumes precipitated hydrous aluminum oxide can have an undesirably high bulk density.

The aqueous sodium aluminate solution does not need to be added at a constant rate take place, but the rate of addition can vary somewhat, e.g. to the extent as it is with a Feed controlled by gravity occurs. The sodium aluminate solution can also be added in portions be added, provided that each serving is one is a sufficiently small part of the total amount to be added or each portion with a suitable one Speed and with sufficient agitation. In practice, the rate of addition and the strength of the stirring depend on others Factors such as the shape and size of the reaction vessel and the amounts of the Reactants, from; In general, however, it is true that a higher or less constant rate of addition, a higher stirring force is required in order to Eliminate the occurrence of extreme conditions in the reaction mixture as far as possible. The reaction mixture will preferably stirred by means of a mechanical stirrer

When performing the process of the invention on a small scale using Solutions with a volume of a few hundred milliliters can be added during a short period Time span down to about 1 minute can be done while performing the procedure on a large scale Scale periods of 15 hours or longer may be appropriate. The addition of the aqueous According to the invention, sodium aluminate solution to the aqueous aluminum sulfate solution is preferably used during a period of at least 15 minutes to a maximum of 1 hour and in particular of about 30 Minutes upwards, e.g. B. from 30 minutes to a total of 45 minutes.

According to a method of the invention, the aluminum sulfate solution can be prepared by a series of Reactors flow, with a corresponding portion of the sodium aluminate solution being continuously fed into each reactor. The total addition time of the Sodium aluminate solution is in this case by the length of time in each reactor and by the Reactor flow rate determined

In the process according to the invention, the temperature of the reaction mixture has a great influence on the nature of the hydrous aluminum oxide obtained. At constant temperatures between about 35 to 45 ° C., the reaction product can contain a large part of bayerite. The aforementioned temperature range is therefore excluded in the process according to the invention. Particularly preferred is a temperature range of 55 to 70 ⁰ C, as in the range of about 35 to 55 ° C, traces can be formed from bayerite. The powder bulk density of the pseudoboehmite produced according to the invention appears to be lowest when the process is carried out within the preferred temperature range and in particular in the range from about 60 to 70.degree. C., for example at 65 or 66.degree.

The sodium aluminate solution preferably has a concentration of at most 10 percent by weight, for example from 2 to 7.5 percent by weight, calculated as AI2O3. The aluminum sulfate solution preferably has

a concentration of at most 7.5 percent by weight and in particular of. at most 6 percent by weight, calculated as Al ₂ O ₃ . According to a particularly advantageous procedure, an aluminum sulfate solution with a concentration of 5 percent by weight and a sodium aluminate solution with a concentration of 24 percent by weight, each calculated as AI2O3, are used added at a practically constant rate, with hydrous aluminum oxide precipitating from the still acidic reaction mixture over about 20 minutes

The composition of the reaction mixture can be determined by using certain amounts of reagents certain concentrations or by stopping the addition of aluminum sulfate at a certain level pH of the reaction mixture can be regulated. In practice, the composition is regulated of the reaction mixture by ending the addition of sodium aluminate when the pH of the mixture is 7.3 to 10.0, in particular from 7.5 to 9.0.

It was found to be incomplete because of the Implementation always at least a small amount of practically insoluble sulfate in the water-containing one Alumina remains. When using a pH method to control the composition of the With the reaction mixture, the amount of sulfate remaining in the water-containing aluminum oxide can be controlled in a satisfactory manner. This is therefore important because in different applications of the hydrous alumina different amounts of sulfate in the Range from 03 to 5 percent by weight calculated as SO3, are preferred. Amounts of sulfate in the foregoing According to the invention, the range is achieved by stopping the addition of the sodium aluminate solution at pH values of the Reaction mixture obtained from 73 to 10.0.

The residual sulfate in the hydrous alumina affects both its powder density and Pore volume as well as the steam stability and the initial activity of catalysts obtained by dispersing metal oxides on the water-containing Alumina and subsequent calcining can be produced. The higher the sulphate content, the lower is the powder density and the higher the pore volume of the hydrous aluminum oxide. The higher the Sulphate content, the lower the initial activity and the higher the vapor stability of the catalysts produced from the hydrous aluminum oxide.

After all of the sodium aluminate has been added, the mixture has an alkaline reaction. The immediate Filtration of the resulting slurry may not always be feasible. When the reaction product ages in an alkaline medium, there is a tendency to Increase in the bulk powder weight of the reaction product. Excessive aging of the reaction product in an alkaline medium can change the structure of the water-containing medium prepared according to the invention Alumina, as determined by X-ray diffraction measurements. The effects of aging on the reaction product appear to be greater at higher temperatures. The slurry should be no more than 3 hours, preferably no more than it 2 hours and especially a maximum of 45 minutes. The addition of the sodium aluminate solution and the aging of the water-containing aluminum nium oxide should be regulated in such a way that the hydrous aluminum oxide is in an alkaline medium for the longest 3 hours

The weight fraction of the pseudo boehmite, calculated as Al ₂ Oj, in the filter cake obtained has a significant influence on the bulk density of the reaction product. The filtration is preferably carried out in such a way that a filter cake with a hydrous aluminum oxide content of 8 to 16 percent, calculated as Al2O3, is obtained.

The filter cake is preferably washed with water. The soluble sodium salts dissolve in the Water, which lowers the content of such salts in the hydrous alumina. That Washing can be done under such conditions that the soluble sulfate is completely removed and only the water-insoluble sulfate remains. The filter cake containing the water-containing aluminum oxide can also be slurried again in water and again up to an aluminum oxide concentration of 8 to 16 percent by weight, calculated as AI2O3, to be filtered.

When the water-containing alumina produced by this invention is to be used for drying of gases or of organic solvents or as a dehydration catalyst is alumina, preferably after drying, calcining, when the calcination at temperatures is carried out from about 300 to 400 ⁰ C, the pseudo-boehmite structure is maintained .

The water-containing aluminum oxide produced according to the invention is also excellently suitable as a carrier for catalysts and is in particular a suitable carrier for at least one compound of a metal from groups Ib, VIa and VIII of the periodic table (with regard to the group name of the periodic table, see Cotton Sc. Wilkinson, "Inorganic Chemistry") ). Such catalysts can be prepared in such a way that a catalyst precursor is first formed by subjecting the water-containing aluminum oxide to at least one metal compound and, if appropriate, subsequent drying. The catalyst is then prepared from the catalyst precursor by calcining

Some of the catalysts that can be prepared in this way are used for hydrodesulfurization The metal compounds used in the production of catalysts for hydrated desulphurization are oxides or compounds of cobalt and nickel (group VIII) and of molybdenum (group VIa) which provide oxides The water-containing aluminum oxide is preferably used with compounds of at least two metals, such as cobalt and molybdenum

The cobalt and molybdenum compounds can be added to the dried hydrous aluminum oxide will. Preferably, however, at least 50 percent of the cobalt and molybdenum compounds are Washed filter cake produced according to the invention added before drying The filter cake is preferably treated beforehand with a phosphate-containing solution. For this, reference is made to the US Pat 24 41 297, in particular Example 3, and ZA-PS 70/6810 are referred to. According to a 'special The preferred embodiment is practically the total amount of the cobalt and molybdenum compounds added to the washed moist filter cake

The aqueous alumina-based catalyst precursor is either dried and

calcined or, if the cobalt and molybdenum compounds were added to the hydrous aluminum oxide only after drying, only calcined. The required for producing an activated catalyst calcination temperature is generally above about 45O ⁰ C. At these temperatures, the pseudoboehmite changes its structure and loses most of its water, wherein a y-alumina is formed. The calcining is preferably carried out at temperatures of 450 to 650.degree. ι ο

The hydrous aluminum oxide produced according to the invention or catalyst precursors produced therefrom can be tabletted or extruded in a known manner. The extrudates are optionally dried and then calcined as described above. The bulk density of the caicinated extrudates can to a certain extent by regulating the temperature and the water content during extrusion can be varied.

The pseudoboehmite produced according to the invention with a low powder bulk density is particularly suitable for the production of catalysts for hydrogenation desulphurisation which contain metal oxides of group VIa and group VIII. In contrast to bayerite, the moist pseudoboehmite filter cake easily accepts the metal compounds that produce oxides. The water-containing aluminum oxide with a low bulk density produced according to the invention and the catalysts produced therefrom have a large surface area per unit weight. They have a greater catalytic activity both per unit weight of hydrous aluminum oxide and per unit weight of metal oxide, compared to aluminum oxides with a higher bulk density or catalysts made therefrom. The catalysts which contain a water-containing aluminum oxide produced according to the invention as a carrier have a comparatively large pore volume. For this reason, the hydrogenated desulfurization catalysts prepared according to the invention are particularly advantageous for the treatment of heavy hydrocarbon oil charges: - '
The examples illustrate the invention.

Examples 1 to 8
and comparative examples V1 to V3

An aqueous sodium aluminate solution (2.5 percent by weight Al2O3) is introduced at a practically constant rate for 30 minutes with stirring into a beaker containing an aqueous aluminum sulfate solution (5.0 percent by weight Al2O3), a mixture being obtained which has a sodium aluminate excess of 5 percent contains. The neutral point is reached after 20 minutes, and the pH value remains below 10 throughout the reaction. The temperature is maintained at the values given in Table I below. The resulting slurry is allowed to age for 30 minutes at the reaction _{temperature and then filtered to the specified Al 2} O ₃ gel. The filter cake is washed three times with 1 liter of water at room temperature. The washed filter cake is ^{dried at 100 °} C., ground and sieved to a particle size of less than 150 microns.

In each example, the powder bulk density of the hydrous alumina is determined as described below, measured. Two weighed and graduated 15 ml centrifuge tubes are added to the 10 ml mark filled with the sample, avoiding both jarring of the glasses and the formation of air pockets will. The centrifuge tubes are placed in a laboratory centrifuge The centrifuge is brought to maximum speed for 1 minute, one held at top speed for another minute and then delayed so that it was after another Minute comes to a standstill. The volume and weight occupied by the sample are then determined Sample determined.

Weight of the sample, g

in the present uci riuu IC, g / Uli i React AI2O3 in Filtra I Ia together Powder- 45 occupied volume, ml la percent Identification by means of i if UgCWlCIIl Description of the r term tion tem- filter functional Schütt Table 1 SO3,
related to X-ray diffraction 1 "Powder bulk density" used is this temperature. cake, Time, weight Weight the dry I. Size has been determined as described above. C. Weight Minutes Washing Example, loss
with him ken weight I. The results are in Tables I and
represents pruzcni Time, 50 Comp.-
example heat, 1.24 Pseudo-boehmite Φ. Minutes percent 2.17 ¥ · Table 9
20th
30th IU
11.8
11.8 10
7th
4th 0.56
0.46
0.45 23.95 1.37 Pseudo-boehmite S. Example, 39 11.6 6th 0.62 V 1 24.48 <l, 0 Bayerite and I. Maybe 43 11.9 5 0.49 55 1 23.64 Pseudo-boehmite 1 example 48 11.8 4th 26th
44
17th 0 ^ 3 2 24.86 <l, 0 Pseudo-boehmite and ι 53
57 11.9
11.9 5
4th 12th 0.42
0.41 V2 <l, 0 <5.0 percent bayerite
Pseudo-boehmite I. 65 11.4 2 20th 036 60 22.08 <l, 0 Pseudo-boehmite and 66 10.7 2 16 0.31 V3 22.34 <5.0 percent bayerite Vl
1
2 72 11.0 2 20th 0.42 3 21.45 <l, 0 Pseudo-boehmite V2 17th 4th <l, 0 Pseudo-boehmite V3 14th 65 2L24 <l, 0 Pseudo-boehmite 3 13th 5 21.67 <l, 0 Pseudo-boehmite and 4th
5 6th 22.14 <5.0 percent bayerite 6th 7th 21.88 7th 8th 8th

Examples 12-13
and comparative examples C4 to C16

The method according to Example 1 to 8 and Comparative Example VI to V3 is repeated with the Except that the concentrations of the aqueous

10

Solutions of aluminum sulfate and sodium aluminate as given in Table II below varied will. Furthermore, in some examples the mixing of the solutions is varied, i. i.e., the aluminum sulfate solution is placed in a sodium aluminate solution. The reaction temperature is 20 ± 3 ° C. The Results are shown in Table II.

Table II

Sodium aluminate concentration (as Al ₂ O ₃ )

Aluminum sulfate concentration (as AI2O3) 1.0 2.5 5.0

Addition of sodium aluminate too Aluminum sulfate

1.0 2.5 5.0

Addition of aluminum sulfate to sodium aluminate

V4
0.84
2.8

V6
0.84
2.6

V7
0.82
1.7

0.38

5.7

0.30

4.7

0.42

2.4

V5
0.73
8.4

11

0.41

6.4

13th

0.31

2.8

V8
1.02
2.8

V 11
0.66
2.6

V 14
0.99
1.7

V9
0.74
5.7

V 12
0.66

4.7

V 15
1.00
2.4

V 10
0.79
8.4

V 13
0.64
6.4

V 16
0.86
2.8

Ex BD C.

Ex BD C.

Ex BD C.

In Table II, Ex denotes the number of the corresponding example or comparative example, BD denotes the powder bulk density and C denotes the aluminum oxide content of the slurry based on the weight, calculated as Al2O3.

Example 14

61.65 kg of solid aluminum sulfate (16.7 percent by weight Al ₂ O ₃ , 37.8 percent by weight SO ₃ ) are dissolved in 145 liters of water in a reactor, a solution with a content of 5 percent by weight Al ₂ O _{3 being} obtained. 86.65 kg of sodium aluminate (21.9 percent by weight Na ₂ O, 25.9 percent by weight Al ₂ O ₃ ) are dissolved in 818 liters of water, a solution with a content of 23 percent by weight Al ₂ O _{3 being} obtained. The sodium aluminate solution is continuously introduced into the sodium sulfate solution at a practically constant rate for 30 minutes, the pH of the equipment being 7 or below for the first 20 minutes and below 10.0 for the entire time. The mixture is at 65.degree continuously stirred by means of a mechanical stirrer. After stirring for an additional 30 minutes, the mixture is run on camber-free filters and washed with distilled water. The filter cake is mixed with a Z-blade mixer for 2 minutes, and cobalt formate, ammonium paramolybdate and water are added. The mixture obtained in this way is mixed for 15 minutes and then poured into dishes and dried at about 90 ⁰ C. After the marriage the powder is mixed with aluminum stearate as a lubricant and the mixture is made into 3.18 mm molds tabletted. The maximum bulk density of the calcined product is 0.3 g / ml. The powder bulk weight of the dried product is 0.22 g / ml.

The term "maximum bulk density" means that which is determined in the manner described below Bulk weight:

The bulk density of a weighed portion of the sample is determined in a 250 ml measuring cylinder BS 604 using a vibrating machine. The jogger is designed so that the graduated cylinder is raised at a rate of 6 to 7 per second and then dropped over a distance of 7.94 mm. The lifting and dropping by means of a helical thumb whose radius is reached during a full revolution uniformly around 7.94 mm increases when the vibrating machine after power has reached its operating speed, the sample-by means of a 25 ml beaker with a

Transferred to the measuring cylinder at a rate of 25 ml per 15 seconds. A total of 220 to 230 ml of the sample are placed in the measuring cylinder. The vibrating machine is then operated for a further 15 seconds allowed to run and then switched off The surface of the sample is attached to a metal rod by means of a attached rubber stoppers leveled. The volume of the sample is then read. After removing the The cylinder contents are weighed using the measuring cylinder from the machine.

Maximum bulk density U / ml -

Volume of the sample, ml

The product is in a standard fixed bed apparatus for hydrodesulphurization using a light hydrocarbon oil fraction with the following properties:

Table III

Specific weight (15.6 ⁰ C)

Sulfur content, ppm

Initial boiling point

Final boiling point

Typical hydrocarbons,

Volume percentage:

Olefins

Aromatics

Paraffins

0.72

350 to 400

40 ⁰ C

175 ⁰ C

0.1
7.1
92.8

IO CoO, percent by weight
MoO ₃ , weight percent
Diameter, mm
Maximum bulk weight

The properties of the hydrocarbon oils to be desulfurized are summarized below.

Kataly Kataly sator A sator B 3.4 3.9 11.6 12.9 2.18 2.46 0.6 0.8

The sulfur is added at 357 ° C., a liquid middle distillate gas oil space velocity of 1.5 and a pressure of 15.1 kgf / cm ² using 36 parts by volume of a 70:30 hydrogen-nitrogen mixture per part by volume of hydrocarbon oil 99 percent away.

(In Examples 14 to 19 and in Comparative Example VI 7, the volumes are at standard temperature and -pressure measured.)

specific gravity (15.6 ° C) sulfur content, percent
Initial boiling point
mean boiling point
Final boiling point
Cloud point

25th

30th

Example 15

55.99 kg of solid aluminum sulfate are dissolved in 136 liters of water (4.9 percent by weight Al ₂ O ₃ ) and, with stirring, for 30 minutes at 65 ° C. at a practically constant rate with a solution of 89.4 kg of sodium aluminate in 836.2 liters Water (2.5 percent by weight Al ₂ O ₃ ) is added. The pH of the mixture remains below 10.0. The mixture is aged for 30 minutes at the reaction temperature. The reaction mixture is then added dropwise to filters over the course of 20 minutes and washed with water for 90 minutes. The Al ₂ O ₃ gel content of the filter cake is 11.8 percent. After cobalt formate and ammonium paramolybdate have been mixed in, the mixture obtained is dried. The dried product is ground and extruded through 2.38 mm openings. The extrudate is calcined. The powder bulk density of the dried product is 034 g / cm ³ . With the catalyst prepared in this way, a desulfurization of 76 is achieved at a middle distillate at a temperature of 357 ° C., a pressure of 15.1 kp / cm ² , a liquid space velocity of 2.0 and, using 178 parts by volume of hydrogen per part by volume of hydrocarbon oil Percent (without pretreatment) obtained.

heavy vacuum gas oil (petroleum mixture) specific gravity (37.8 ° C) sulfur content, percent
Nitrogen content, percent
Pour point

Vacuum distillation (approximate values) initial boiling point
mean boiling point
Final boiling point

0.876 2.06 268 ° C 324 ° C 393 ° C

0.882 1.55 0.13 32.2 ⁰ C

250 ° C 45O ⁰ C 58O ⁰ C

Examples 16
umi comparative example VI 7

Catalyst A used in Example 16 is prepared according to the procedure described in Example 15

In comparative example V17, leg is used as the catalyst Standard catalyst for hydrated desulphurisation based on aluminum oxide, which is produced in an analogous manner by precipitation of water-containing Aluminum oxide, which contains a considerable amount of Bavaria, is produced. Failing this Hydrous aluminum oxide is made from a reaction mixture of sodium aluminum and aluminum sulfate The process steps following the precipitation are carried out according to Example 15. The properties of the catalysts thus produced are summarized in Table III

50

55

60

65 percent desulfurization of the middle distillate *)

Liquid-Space Catalyst A Catalyst B

speed

1 89.0 90.9

2 76.8 82.0

3 67.2 71.6

4 59.5 62.4

*) At 357 ° C, 15.1 kp / cm ² and using parts by volume of hydrogen per part by volume of hydrocarbon oil.

Percentage desulfurization of the heavy vacuum gas oil *)

Liquid space velocity

Catalyst A

Catalyst B

1 93.9 93.9

2 85.2 85.2

3 78.8 75.6

4 67.0 62.6

*) At 371 "C, 53.7 kp / cm ² and using parts by volume of hydrogen per part by volume of hydrocarbon oil.

Examples 17 to 19

A solution of 140 kg of sodium aluminate in 1280 liters of water is converted into a solution of 180 kg aluminum sulphate immersed in 108 liters of water

The addition takes place continuously over 33 minutes, with a pH of 7 after 21 minutes is achieved. The temperature of the solutions is kept at 67 to 68 ° C. After all of the

Sodium aluminate solution is pH 5

Mixture 8.8. The mixture is then stirred for a further 30 minutes. The reaction mixture is then poured into shared two equal parts. Each half is filtered and washed 4 times with 805 liters of water each time. Afterward the two halves are reunited. Then ι ο the approach 3 parts of each Vs of the total amount taken. Each part is washed with a further 200 liters of water and for about 30 minutes with 100 percent Phosphoric acid mixed. The resulting mixture is coated with a cobalt formate slurry for about 15 minutes Slurried and then mixed with an Ammoniummoiybdatiösung for about 30 minutes All mixing and slurrying operations are carried out in a ball mill. The for Treatment of each of the above parts used amounts of 100 percent phosphoric acid, cobalt formate and ammonium molybdate are summarized in Table IV.

Table IV also contains the contents of the cobalt compound based on the calcined aluminum oxide support, calculated as CoO, and the molybdenum compound, calculated as MOO3, after this first Treatment stage in each of the aforementioned parts of catalyst C D

Cobalt hydroxide, g 22.4 23.9 5.5

Formic acid, ml 25 27 6.1

Water 60 60 14

Ammonium molybdate 270 175 90 solution *), ml

*) The ammonium molybdate solution contains 2½ percent by weight of molybdate, calculated as MOO3.

Each portion is then filtered, processed by extrusion to Peliets with a Soiidurchmesser of i, 59 mm, dried for 15 hours at 80 to 90 ⁰ C and then calcined 2 hours at 550 ⁰ C. The catalysts thus obtained are hydrogenated to their catalytic activity in the Desulfurization in a standard experimental facility at a temperature of 357 ° C, a pressure of 15.1 kgf / cm ² , a liquid space velocity of 2.0 and using 178 parts by volume of hydrogen per part by volume of hydrocarbon oil and a diesel oil charge with the values in the table VI specified characteristic values checked. The results are summarized in Table VII

catalyst D. will f E. 30th Table VI catalyst D. 1.78 Table IV Sulfur content C. 218 ⁰ C C. 0.623 filtered 48 0 Initial boiling point 0.595 0.575 mean boiling point 1.9 302 ° C 0.410 0.655 0.630 according to ASTM 1.1 3.70 358 ° C 0.588 1.487 1.435 35 Final boiling point 3.70 12.8 0.862 0.647 6.35 5.6 specific weight 13.4 H3PO4, kg 1.47 Table VII 342 Cobalt hydroxide, kg 6.25 3.20 3.60 326 0.54 Formic acid, kg 11.30 11.95 40 0.53 167 E. Water, kg 3.27 *) The Ammoniummoiybdatiösung contains 25 1 3weight 141 Ammonium molybdate 10.50 Percent molybdate calculated as M0O3. solution *), kg 0 Cobalt, percent CoO The parts thus obtained hours 45 Phosphate (percent P ₂ O ₅ ) 3.60 Molybdenum, percent MoO ₃ Cobalt oxide (percent CoO) 12.1 Molybdenum oxide (Percent MoO ₃ ) 312 50 surface 0.55 Bulk weight 119 VRA

dried at 80 to 90 "C and then ground. 4.15 kg are removed from each part and the like Treated in the same way as in the first stage with cobalt formate and ammonium molybdate The cobalt formate used and amounts of ammonium molybdate are shown in Table V.

In Table VI, VRA is a measure of the catalytic

Activity, with a high VRA value being good catalytic Properties in the hydrogen desulfurization indicates In Table VIl, the percentages are on the Weight of calcined catalysts based.

Claims (2)

Patent claims: 1. A process for the preparation of hydrous aluminum oxide by mixing an aqueous aluminum sulfate solution with an aqueous sodium ^: aluminate solution, separating the precipitated hydrous aluminum oxide from the reaction mixture and washing the reaction product, characterized in that an aluminum sulfate solution with a concentration of at least 2 percent by weight , calculated as Al ₂ O ₃ , mixed with a sodium aluminate solution up to a stoichiometric excess of 10 percent aluminum sulfate to 10 percent sodium aluminate so that the sodium aluminate solution is added with stirring at such a rate that at least half, preferably at least 2/3 of the hydrous aluminum oxide precipitates from the reaction mixture as long as it has a pH value in the acidic pH range, that the addition of the sodium aluminate solution continues until the reaction mixture has reached a pH value of 73 to 10.0, that one d holds ie temperature of the reaction mixture in the range of 12 to 35 ° C or from 45 to 7O ⁰ C, that is allowed to age more than 3 hours in the alkaline range, the obtained slurry of the hydrated alumina, which comprises separating the water-containing alumina and optionally washed and / or dries and, if necessary, calcined at temperatures in the range from 300 to 400.degree 2. Use of the hydrous aluminum oxide according to claim 1 for the production of Catalysts, especially those loaded with metal components and through a calcination bed treatment of activated catalysts for hydrogen desulfurization.