DE1442833C - Process for the catalytic cracking of hydrocarbons - Google Patents

Description

In the catalytic splitting of hydrocarbons, where z. B. Hydrocarbon oils of higher boiling ranges into hydrocarbons of lower boiling ranges, especially in the motor fuel area boiling hydrocarbons are converted solid materials that are acidic are mainly used as catalysts.

Although acidic catalysts of this type have one or more beneficial properties, they have very many of these catalysts have undesirable characteristics, such as lack of thermal stability, availability or mechanical strength, etc. Synthetic silica-alumina compounds, the most common of the catalysts proposed so far offer only a limited yield of gasoline at a given coke yield and also have the disadvantage that in the presence of steam, in particular at temperatures above 538 ° C, they quickly become inactive. Other less common catalysts include clayey materials, e.g. B. bentonite and montmorillonite, which are treated with acid to have cleavage properties. Catalysts are of this general type relatively cheap, but they have only moderate activity and show a decrease in activity many change and regeneration cycles. Some synthetic materials such as B. silica-magnesia complexes are more active than conventional ones Silica-Alumina Catalysts and are subject to normal aging they have however, limited usefulness because of their low product distribution, as is the case with e.g. B. by receiving Shows low octane gasoline.

It is also known to produce bentonite catalysts, both dried and powdered Bentonite is treated with concentrated sulfuric acid without subsequent washing. The treatment takes place in a temperature range known per se for the ion exchange with an amount of acid, which equals the ion exchangeability of bentonite, or which is based on a factor of 1.1 to 1.15 on bentonite free of acid-consuming contaminants, is higher. These catalysts are strongly acidic and can, for example, in phenol alkylation and dehydration, isomerization, Cyclizations or dehydrogenations find application.

Finally, it is also the production of fission catalysts from bentonites by acid treatment known, with the bentonites used as starting material practically of all proportions soluble in acid completely freed and then with calculated amounts of a dissolved aluminum compound impregnated and this is thermally or chemically decomposed.

These catalysts are acid-treated clays. but those by the acid treatment so high a number of hydrogen ions cannot be introduced as they are found to be is required for a particularly advantageous catalytic cracking of hydrocarbons.

It also describes the preparation of certain crystalline zeolites from crystalline aluminum silicate in which about two thirds of the sodium is replaced by a metal ion. It is finally known to use crystalline sodium aluminosilicate as a carrier for platinum metal groups. When using such zeolites cannot give excellent results in catalytic cracking can be obtained from hydrocarbons.

The object of the invention is to create a method for the catalytic cracking of hydrocarbons using a crystalline, hydrogen-containing aluminosilicate in which a very favorable product distribution in terms of the yields of desired products with a long service life at the same time the catalysts is achieved.

ίο The method according to the invention for catalytic Columns of hydrocarbons, in which the feedstock is based on a catalyst of a crystalline, hydrogen-containing aluminosilicate brought into contact under dissociation conditions is characterized in that one uses an aluminosilicate which is less than 0.25 gram equivalents Contains alkali and at least 0.5 gram equivalents of hydrogen per gram atom of aluminum and is dispersed through a matrix, optionally with a mild steaming treatment 428 to 816 ° C.

The activated aluminosilicate used as the catalyst contains at least 0.5 gram equivalents, preferably but more than 0.9 graphic equivalents

as hydrogen per gram atom of aluminum. Except the Alkali cations containing up to less than 0.25 gram equivalents per gram atom of aluminum as impurities may be present, no metallic cations are associated with the aluminosilicate. With subsequent combination, dispersion or intimate mixing in another way of the Aluminosilicates with a grain size of less than 40 microns with an inorganic oxide gel proved found this product to be an unusually active catalyst for catalytic cracking.

The catalyst can be used in the powdered, granular or pressed state, formed into spheres or tablets of finely divided particles with a particle size between the mesh numbers of 2 to 500 sieve units. In cases where the catalyst has been pressed, e.g. B. extrusion, the aluminosilicate can be pressed or dried or partially dried and then pressed prior to drying. The catalyst product is then preferably precalcined, in an inert atmosphere near the temperature intended for conversions, but can also be calcined initially during use in the conversion process. Generally, the catalyst at temperatures of 65-600 ° C is dried and afterwards in air or in an inert atmosphere of nitrogen, hydrogen, helium, flue gas or other inert gas at temperatures ranging from about 260-815 ⁰ C for 1 to 48 Calcined for hours or more.

A preferred embodiment of the in the Ver · ^ drive according to the invention to be used catalyst consists in a catalyst that by Dispersion of finely divided particles of the critical

staline aluminum silicates in a silicon-containing one Gel carrier is obtained in such proportions that the resulting product is about 2 to 95 percent by weight, preferably about 5 to 50 percent by weight of aluminum in the final composition contains.

The compositions of the aluminosilicate and the silicon-containing gel can be made by several methods be produced, whereby the aluminum

3 4

Silicate is combined with the silicon dioxide, solution has been dispersed and this mixture then

while the latter is in a water-containing additive with sulfuric acid-aluminum sulfate solution in the

was located, such as B. in the form of a hydrosol, nozzle mixer was dispersed. This way of working

Hydrogel, a wet, gelatinous precipitate leads to the formation of pearl-shaped hydrogel in which

or a mixture thereof. Thus, silicon 5 can dissolve the aluminum silicate very finely in the matrix

Dioxydgel is dispersed in the hydrolysis of alkali silicate. .

an acid, such as hydrochloric acid, sulfuric acid, etc., un- The resulting hydrogel was _{mixed with NH 4} Cl (admixtures 1 and 2 with finely divided aluminum silicate), CO ₂ water (Example 3) or NH, HCO ₃ , which has a grain size of less than (Example 4) exchanged for the remaining sodium 40 microns, but preferably less than 2 to 10 microns from both the crystalline aluminosilicate and 7 microns. The mixing of the two silica-alumina hydrogel to the resulting parts can be removed in any desired way. . be taken, such as B. in a ball-bearing mill. Analyzes have found that the sodium or in other types of kneading mills. The resulting mixture of silicon-containing gels with aluminum was 0.1 to 0.2 percent by weight, based on the finished sodium silicate, which was washed free of soluble salts. The gram equivalents of water and then, if desired, dried and / or substance per gram atom of aluminum were all calcined. Examples above 0.5.

The silicon-containing gel carrier can also consist of a multicomponent gel with a predominant proportion of Si. B. by its ability to convert a silicon dioxide with one or more oxides of gas oils (Mid-Continent Gas Oil) with a boiling group II, III, VI, V, VI, VII and VIII of the range from 232 to 510 ^c C to gasoline. with an endodic system. In particular, multi-be boiling point of 21O ⁰ C to catalyze. Vapors of the substance gel of silicon dioxide with metal oxides of the gas oil are for 10 minutes at temperatures groups IIA, IHB and IVA of the periodic 25 of 468 or 482 ° C, preferably under normal pressure system, the metal oxide being magnesium oxide, aluminum and at a feed rate of 1, 5 minium oxide, zirconium oxide, beryllium oxide or tho- to 16.0 volumes of liquid oil per volume of potassium oxide is preferred. The production of multipliers per hour passed through the catalyst, material gels is generally known and generally comprises either separate precipitation or common precipitation techniques, with one suitable . .

Salt of the metal is added to an alkali silicate and an acid Example 1 or base, as required / required, in order to precipitate the corresponding 25 parts by weight of a synthetic crystalline speaking oxide. The silicate content of the aluminosilicate of the zeolite X type in a pebble-like gel carrier intended here is in the 35 silicon dioxide-aluminum oxide matrix ■ from 93 common compounds within the range of 55 to 100 percent by weight SiO ₂ and 7 percent by weight Al ₂ O _a weight percent, with the Metal oxide content dispersed between, which gels with sulfuric acid, with water: 0 and 45 ° / “is. washed and dried. The together! In one embodiment, aluminum * exposure was then six 2-hour and two _/ silicate catalysts with unusually high levels of activity with a two-molar '! ity orders of magnitude are used, which are subjected to the solution of ammonium chloride, ge! Incorporation of a Metallaluminiumsilicats in a wash until the effluent contained no chloride, geanorganischen Oxydgelträger be prepared WOR ion and dried for 20 hours at about 663 ⁰ C on the aluminosilicate with hydrogen or treated with 100 ° / "steam at atmospheric pressure. \ Ammonium ions convertible into hydrogen ions 45 The aluminosilicate obtained had a sodium contact. content of 1.09 percent by weight. It was about 0.21 j. Furthermore, it has proven to be useful that up to 0.23 gram equivalents of sodium per gram atom! the treated aluminosilicate precedes a mild steam aluminum in the finished catalyst. treatment in the range of 428 to 816 ^C C, preferred The catalyst has been used to crack gas oil at temperatures up to about 704 ° C, below about 468.5 ° C, with the following results. The treatment can in an atmosphere: sphere of 100 ° / ₀ steam or in an atmosphere table Γ made of steam and gas. the

Steam treatment apparently produces beneficial conversion, 50.9% by volume

Properties in the aluminum silicate. 55 Room air velocity / h .... 1.5

In the manufacture of the catalytic converters for the after- gasoline, percent by volume

The standing examples each have a sodium silicate (Reid vapor pressure of 10) 38.4

solution containing the dispersed crystalline aluminum. Excess of C ₄ compounds,

Contained silicate, with a sulfuric acid-aluminum volume percent .. . 15.7

sulfate solution gelled. A complete mixture of 60 C ₅ + gasoline, 37.1 percent by volume

this solution was achieved in that the Lö total C ₄ , percent by volume 15.4

Solutions through a nozzle with fixed flow drying gas, weight percent 5.7

speeds were allowed to flow. Coke, weight percent 2.7

The dispersion of the crystalline aluminum ■. . . '

silicats in the silicon dioxide-aluminum oxide matrix 65 e 1 s ρ 1 e

was brought about by first vigorously mixing the aluminum 10 parts by weight of a crystalline aluminosilicate with water and of the zeolite Y type in a silicon dioxide, then this slurry thoroughly in the sodium silicate-aluminum oxide matrix of 94% by weight SiO ₂

and 6 weight percent Al ₂ O ₃ dispersed, which was gelled with sulfuric acid, washed with water and dried. The composition was then subjected to twelve 2-hour treatments with 0.1 weight percent aqueous solution of ammonium chloride at room temperature, washed with water until the effluent contained no chloride ions, and for 24 hours at about 663 ° C with 100% steam at a pressure of about 1, 05 atü treated. The resulting aluminosilicate had a sodium content of 0.27 weight percent. There was about 0.01 to 0.09 gram equivalents of sodium per gram atom of aluminum in the catalyst.

The catalyst was used to crack gas oil at about 482 "C, with the following results were obtained:.

Table II

Conversion, volume percent 60.3

Room air velocity / h .... 2 gasoline, percent by volume
(Reid vapor pressure of 10) 49.4

Excess of C ₄ , percent by volume 12.7

C ₅ + gasoline, volume percentage 47.1

Total C ₄ , volume percent 14.9

Dry gas, weight percent 7.4

Coke, weight percent 1.7

H ₂ , weight percent 0.03

B e i s ρ i e 1 3

25 parts by weight of a crystalline aluminosilicate of the zeolite type were _{dispersed in a silica-alumina matrix composed of 94 percent by weight SiO 2} and 6 percent by weight Al ₂ O ₃ , which was gelled with sulfuric acid, washed with water and dried. The composition was then given twenty-two 2 hour saturated carbonic acid treatments, geysed with water until the effluent did not contain chloride ions, and treated with 100% steam at atmospheric pressure at about 663 ° C for 24 hours. The aluminosilicate obtained had a sodium content of 0.9% by weight. There was about 0.17 to 0.22 gram equivalents of sodium per gram atom of aluminum in the catalyst. When tested according to the procedure according to Example 2, the catalyst had the following cleavage properties:

Table III

Conversion, percent by volume 39.1

Room air velocity / h .... 4 gasoline, percent by volume

(Reid vapor pressure of 10) .. 31.6

Excess of C ₄ , percent by volume 7.0

C ₆ + gasoline, volume percentage 29.4

Total C ₄ , volume percent 9.2

Dry gas, weight percent 5.0

Coke, weight percent 2.7

H ₂ , weight percent 0.039

B e i s ρ i e 1 4

The procedure of Example 3 was repeated with the modification that instead of carbonic acid a 2 weight percent aqueous solution of ammonium carbonate would be used. The sodium content of the resulting catalyst was 0.45, with 0.06 to 0.08 gram equivalents of sodium each Gram atom of aluminum were present in the catalyst,

ίο its cleavage properties in the following Table shows:

Table IV

Conversion, percent by volume .... 39.4

Room air velocity / h 4

, Gasoline, volume percentage

(Reid vapor pressure of 10) 33.9 excess of C ₄ , volume percent 7.4

C ₅ + gasoline, volume percent 31.6

Total C ₄ , volume percent 9.7

Dry gas, weight percent 4.5

Coke, weight percent * .. 1.4

H ₂ , weight percent 0.024

Claims (5)

Patent claims: 1. Process for the catalytic cracking of hydrocarbons using the feedstock with a catalyst based on a crystalline aluminosilicate containing hydrogen cations is brought into contact under fission conditions, characterized in that that an aluminosilicate is used which has less than 0.25 gram equivalents of alkali and at least 0.5 gram equivalents Contains hydrogen per gram atom of aluminum and is dispersed through a matrix and that optionally a mild steam treatment at 428 to 816 ° C. 2. The method according to claim 1, characterized in that one uses an aluminosilicate, in which the atomic ratio of silicon to aluminum is greater than 5.0. 3. The method according to claim 1, characterized in that an aluminosilicate is used, wherein the atomic ratio of silicon to aluminum is greater than about 2.7 and less than about 5.0 is. 4. The method according to any one of claims 1 to 3, characterized in that the matrix consists of a inorganic oxide gel. 5. The method according to any one of claims 1 to 4, characterized in that the matrix consists of a silicon-containing material is formed.