DE974205C - Process for the production of spherical catalysts or catalyst carriers with a diameter between 10 and 200ª - Google Patents

Description

(WiGBl. P. 175)

ISSUED OCTOBER 20, 1960

gg IVa / 12g D

In the case of a catalytic process with moving contacts, e.g. B. in splitting, reforming, hydrogenating, dehydrating, Cyclizing, aromatizing, alkylating, isomerizing, Polymerizing, desulphurising of petroleum products, coal tar products and related substances, According to a customary embodiment, the catalyst particles are in cocurrent or countercurrent passed through the reaction space with the flowing material to be treated. Afterward the catalyst particles and reaction products are separated from one another, and the catalyst is in regenerated in a separate zone before returning to the reaction vessel.

It has now been found that spherical catalysts or catalyst supports which are particularly suitable for such catalytic processes and have a diameter between 10 and 200 μ can be produced by washing out hydrogels or hydrogel mixtures produced in a known manner, dispersing them in water and then subjecting them to spray drying.

Catalyst particles in spherical shape with the specified dimensions, which are suitable for the use of Flow contact methods are suitable, according to the invention from materials such as oxides, sulfides and basic sulphides of iron, chromium, bismuth, boron,

009 622/14

Aluminum, gallium, copper, nickel, beryllium, titanium Indium, zircon, thorium, cerium, scandium, vanadium. Manganese, Magnesium, Silicon, Lantan, Germanium, Tin, tantalum, molybdenum, tungsten and their mixtures can be produced.

One can also use hydrogels that are made up of two or more oxides of the elements in question derive, produce by mixing several soluble salts of the catalytic substances with alkali or solutions

ίο acid (depending on the catalytic acting material) in such an amount and concentration that one of a mixed Hydrogel formed reaction product forms. The hydrogel is used before further treatment washed out. Washing is done with hot or cold water and by (several times if necessary) Decanting or filtering, etc. made. In the examples below, the preparation illustrated by hydrogels suitable for carrying out the invention.

Example ι

To prepare a tin oxide gel, an aqueous solution of 3 to 7 percent by weight sodium stannate, an acid solution, for example hydrochloric acid or sulfuric acid, is added until the hydrogen ion concentration of this mixture is within the range from ¹ ₁₀ to ⁵ ₁₀ mol / l ; vigorous stirring is carried out during the reaction. The sol formed in this way coagulates in a short time after the end of the reaction and forms the hydrogel.

Example 2

The hydrogel of titanium oxide is produced from sodium titanate in the manner described in Example ι.

Example 3

To prepare the hydrogel from tungsten oxide, a solution of is added with vigorous stirring 3 to 8 percent by weight of sodium tungstate to sulfuric or hydrochloric acid, with a precipitate forms. Only a small amount of acid is required for this. The reaction mass is stirred for so long until the precipitate dissolves again, after which more acid is added; the total amount to be applied Acid is measured in such a way that, after the reaction has ended, a final acidity of 0.1 η results in up to 0.5 η. At this acidity, the reaction mixture or the sol coagulates at room temperature forming a hydrogel of tungsten oxide within less than 30 minutes.

Example 4

By mixing equal amounts of an aqueous solution of aluminum sulfate that is about 5 to 10 percent by weight of the salt contains, with a 1N solution of an alkali, for example a sodium hydroxide or Ammonium hydroxide solution is used to make the hydrogel of aluminum oxide. The reaction will preferably carried out at a temperature of about 0 to 5 ° C with stirring. The aluminum oxide occurs as a hydrated gel ..

Example 5

You can also use the method of Examples 1 and 2 in conjunction with the aluminum oxide gels Manufacture of tin oxide and titanium oxide gel using sodium aluminate as the starting material used.

Example 6

Intensive mixing of a 10% hydrochloric acid solution and a sodium silicate solution with a specific gravity between 1.1 and 1.3 produces a silica sol which ^{coagulates at 50 °} C. with gel formation within 30 to 60 minutes.

The hydrogel or the mixture of hydrogels obtained in a manner known per se is after described washing treatment dispersed in water and by means of a suitable spraying or Atomizer introduced as a mist in a gas of such temperature that drying at least is effected to the point at which the spherical shape of the mist particles is stabilized.

In many cases it is beneficial to use the catalyst cake completely dry at this stage of the process. But it can also be useful at times be, the particles in this stage only partially up to a stabilization of their shape guaranteed Degrees to dry and then complete the drainage in a rotary kiln.

The particle size can be regulated as desired by the conditions during the atomization in a manner known per se. Advantageous for drying of the spray are temperatures of the drying air in the range 90-540 ⁰ C. It can be advantageous to about 8oo ° C, higher temperatures may also, in particular when a short residence time of the catalyst is desired in the drying step.

If the catalyst particles are only to be pre-dried in the atomization stage until dimensional stability is achieved, temperatures significantly below 90 ^° C. down to room temperature can often suffice.

A process for making spherical silica-alumina catalyst particles which are particularly suitable for splitting petroleum products in flow contact processes is shown in the drawing illustrated.

In the illustrated embodiment, a sodium silicate solution with a specific gravity is used of about 1.2 transferred from the storage container 1 into the vessel 4, which is equipped with a stirrer 10, and mixed there with an aqueous hydrochloric acid solution (10 percent by weight) from container 2. From the container 5 an aqueous solution containing 7 percent by weight of aluminum sulfate is poured into the 11 provided with stirrer • ef äß 8 initiated and there with a 1N solution of ammonium hydroxide from container 6. From the vessels 4 and 8 get the Mixtures that essentially contain silicic acid hydrogel or aluminum oxide hydrogel, in the with

Vessel 9 provided with stirrer 12. From this vessel the mixture is passed to a continuous filter 13, in which the hydrogel mixture for the purpose of removing the remaining impurities, in particular from sulphates and chlorides, is washed exhaustively. The washed gel mixture will transferred into the vessel 14 provided with stirrer 15, where it is dispersed in water. The gel dispersion obtained in this way reaches the container 16 from the vessel 14, from which it passes through line 18 under a pressure of approximately 140 atm with the aid of the pump 17 to a spray nozzle 19, which sprays the dispersion into the upper part of the cyclone 20. This is done by the hot air or hot flue gas entering the cyclone via line 21 causes rapid evaporation of the water from the mist particles, and spherical alumina-silicic acid particles remain pass from the cyclone 20 through line 22 into the rotary kiln 23, where they are completely dried. the end Ao the furnace 23, the finished spherical catalyst particles pass through line 24 into the storage container 25th

If at point 19 of the apparatus a gas atomizer is used, as indicated at 7, a gas feed line should be provided through which air or flue gas or a similar atomizing medium can be supplied under pressure.

Small amounts of fine aluminum oxide-silica particles that can arise in cyclone 20, enter the second cyclone 27 with the exhaust gases via the line 26, where the main part of the fine particles is separated from the gas-water vapor mixture, which from cyclone 27 through the Line 29 exits. The fine particles collected in cyclone 27 are conveyed through line 28 to the container 14 returned, where they are fed to the hydrogel dispersion. These particles are doing it at least partially rehydrated to a form suitable for spraying. If the very fine particles are unsuitable for this, they can be removed from the system through line 3.

Traces of fine alumina-silica particles that were not precipitated in cyclone 27 with the escaping gas-water vapor mixture pass through line 29 to an electrostatic precipitator 30, in which the fine particles are practically completely removed. The ones down here Particles pass through lines 31 and 28 into container 14. The gas-water vapor mixture freed from the finest particles is discharged through line 32.

In the production of supported catalysts, such as boric acid on aluminum oxide, are spherical alumina particles or the like formed in the manner described above, and then boric acid is mixed with the dried particles, whereupon the impregnated particles are further dried will. Boric acid can also be added to an alumina gel before the spherical Particles are formed. In a corresponding manner, other supported catalysts can be impregnated spherical particles with a suitable acidic, alkaline or neutral compound or mixture of the material to be applied.

Spherical catalysts produced according to the invention can be of the most varied Embodiments of methods with moving catalysts can be used. Particularly beneficial is their use in flow contact processes with regeneration, i. H. in proceedings in which a catalyst with the aid of a vapor or a liquid from a reaction zone to a regeneration zone and is passed back to the reaction zone.

Claims (2)

Patent claims: 1. A process for the production of spherical catalysts or catalyst carriers having a diameter between 10 and 200 μ, characterized in that hydrogels or hydrogel mixtures produced in a known manner are washed out, dispersed in water and then subjected to spray drying. 2. The method according to claim 1, characterized in that that the hydrogel particles are only partially dried during spray drying and that the dewatering in a subsequent process stage, preferably in a rotary kiln, is carried out to the end. Considered publications: German patent specifications No. 119 279, 188 503, 225 705, 711 317, 725 080; French Patent Nos. 820 917, 855 378; British Patent No. 303 138; U.S. Patents Nos. 1,806,663, 1,773,273, 2250421, 1843576; Ullmanns Enzyklopadie der technischen Chemie, 2nd edition, 5th volume, 1930, pp. 437 to 442; 6th volume, 1930, p. 713; 9th Volume, 1932, p. 509; Alfred Kuhn, Dictionary of Colloid Chemistry, 1932, pp. 87/88. Older patents considered: German patents nos. 896 189, 764 705. 1 sheet of drawings © 009 622/14 10.60