FR2503731A1 - CATALYST SYSTEMS FOR THE CRACKING OF HIGH BOILING POINT HYDROCARBON FRACTIONS - Google Patents

Abstract

The invention relates to catalyst systems for cracking higher-boiling hydrocarbon fractions to give motor fuel components. The aim of the invention is to produce cracking catalysts having an improved selectivity in the formation of motor fuel components during the cracking of higher-boiling hydrocarbon fractions. The object of developing a catalyst system of an appropriate composition is achieved by a catalyst system which contains zeolitic alumosilicates, preferably of the NaY type, whose Na<+> cations have been exchanged to the extent of 60 to 95 equivalent % by hydrogen or ammonium cations and/or cations from the second main group and/or third main group and/or subgroup of the Periodic Table of the Elements, in a quantity from 1 to 50% by mass, an X-ray-amorphous alumosilicate having an Na2O content of 0.03% by mass and an SiO2 content from 1 to 90% by mass in a quantity from 5 to 90% by mass, if appropriate a peptisable binder in a quantity from 1 to 30% by mass, one or more heavy metal compounds on an oxide support, which contains 1 to 10% by mass of one or more compounds from the first to the second main group of the Periodic Table of the Elements, in a quantity from 0.1 to 20% by mass.

Description

The invention relates to catalyst systems for cracking high boiling hydrocarbon fractions into fuel products, which can be used in a catalytic cracking process with a mobile catalyst bed.

Catalytic cracking processes can be carried out in various technical ways. There are processes which are carried out with fixed catalysts, and others with a mobile catalyst bed. The most modern process of the latter type is the so-called "riser" process, according to which the cracking process operation 8 is carried out in what is called a cloud of flying dust. For this process it is necessary to use microspheric, abrasion resistant catalysts which exhibit high activity as well as good thermal and hydrothermal stability during pretreatment, reaction and regeneration. In addition, good resistance to poisoning with respect to nitrogen, sulfur and metal impurities is required. The catalysts which meet these conditions preferably consist of mixtures of crystallized, activated aluminosilicates and aluminosilicates of amorphous structure under X-rays, as well as in certain cases of aluminum oxide. These catalysts, however, have certain significant drawbacks.

1. For example, they form relatively a lot of pod and gas, at the expense of the formation of liquid products.

2. They only decompose the sulfur and nitrogen compounds in an insufficient proportion, so that the cracked gasoline formed must undergo further processing and / or a hydrorefined raw material must be used.

3. A relatively large proportion of naphthetic cyclic compounds undergo cracking, and these compounds are then no longer available for the formation of aromatics.

The defects mentioned limit the profitability of catalytic cracking processes.

The object of the invention is to provide catalyst systems for the catalytic cracking of hydrocarbon fractions into fuels, these systems exhibiting an improvement in the selectivity in the formation of liquid reaction products, in particular of fuels and aromatics, as well. than a higher activity for the decomposition of heterogeneous organic compounds.

The invention therefore proposes to develop a system of catalysts for the cracking of high-boiling hydrocarbon fractions, of suitable composition, the use of which allows, with better selectivity, higher fuel yields to be obtained. To this end, the invention provides catalyst systems for cracking high-boiling hydrocarbon fractions into fuels, characterized in that they contain:
- zeolitic aluminosilicates, preferably of the NaJ type, in which the Na + ions have been exchanged
Up to 60 to 95 * of equivalent by hydrogen, ammonium cations and / or cations of the 2nd and / or 3rd main groups and / or subgroups of the periodic system of the elements, in a proportion of 1 to 50 * in mass,
- an aluminosilicate with an X-ray amorphous structure, with an Na20 content of at least 0.03 * by mass and an SiO2 content of 1 to 90 * by mass, calculated on the material calcined at 1073 K, in a proportion from 5 to 90 * by weight,
- optionally a peptizable binding agent, in a proportion of 1 to 30% by weight,
- one or more heavy metal compounds of the 6th group of the periodic system deposited on an oxidized support, in a proportion of 0.1 to 20% by mass,
- this oxidized support, which comprises from 1 to 10 * by mass of one or more compounds of an element of the first or of the second main group of the periodic system of the elements, in a proportion of 0.1 to 20 * by mass .

These catalyst systems preferably contain 5 to 25% by mass of zeolite aluminosilicates, 10 to 80% by mass of X-ray amorphous aluminosilicates 10 to 25% by mass of Boehmite hydrogel as a peptizable binder, and 1 to 10 by mass of heavy metal compounds on an oxidized support.

Advantageously, the oxidized support contains aluminum oxide, silicon dioxide or aluminosilicate, and as elements of the 1st and 2nd main groups of the periodic table of the elements, potassium, cesium, calcium or magnesium.

As a combination of heavy metals, the oxides and / or sulphides of molybdenum and / or tungsten are used, in proportions of 1 to 10% by weight.

Heavy metal compounds can be introduced into the catalyst system in different ways. The preferred variant consists in that starting from aluminum oxide, which can be stabilized by silicon dioxide, together with the heavy metal compound and the other compounds mentioned above, is prepared by separate routes, by dispersion and atomization, microspheric particles having a diameter of 10 to 150+, preferably 30 to 120fi, the mechanical mixtures of which in a ratio of 0.01 to 1, preferably 0.05 to 0.2 can be used as catalyst systems according to the invention. A possible variant also consists in that, from all the components indicated, an aqueous dispersion or a dispersion in a mineral acid is prepared, which is dried in the atomization of so as to give microspheric particles with a diameter of 10 to 150.4, preferably 30 to 120 T. Surprisingly, a catalyst system, which additionally contains heavy metal compounds, outperforms common catalysts in activity and selectivity.

The invention will be better understood with the aid of the examples below.

Example 1
Catalyst A (catalyst according to the prior art) is a microspheric FCC catalyst, which is prepared from a mixture of 20 by mass of
Boehmite, 60% by mass of aluminosilicate with a proportion of SiO2 of 85% by mass, and 20% by mass of an NaJ zeolite established at 90 * equivalent with bin + ions and a mixture of SE3 + ions, and which, after calcination at 873K for 8 hours, undergoes a hydrothermal treatment at 1023K
Example 2
The catalyst system B (according to the invention consists of a mixture of 5 parts of catalysts A and 1 part of an atomized aluminum oxide, which contains 1.8% by mass of CaO and 10% by mass of Mo03
Example 3 (comparison)
These catalysts are subjected to a micro-cat-A test.

Conditions:
amount of catalyst: 5g of dry substance
grain size: 63
catalyst / oil ratio; 2.8
temperature: 753K
pressure: 0.1 MPa
load: 20g / gh
crude material: distillation product
under vacuum (boiling
between 623 and 773 K with
0.33 * by mass of
sulfur) catalyst AB total reaction in% (mass) 80.5 72.1 liquid product ll n 74.1 84.1 gasoline (c5 + boiling ll ll 54.6 56.2 up to 453K) cracking gas "" 16.8 7.9 coke "" 9.1 8 selectivity 'I n 068 0.78 (gasoline)
By gasoline selectivity is meant the ratio of the proportion of gasoline to the total reaction. The data in% by mass refer to the raw material used.

Catalysts A and B have been tested for their ability to decompose sulfur products and the composition of liquid products. The reaction conditions were those of Example 3
Catalyst AB total reaction * by mass 80.5 72.1 liquid product II "74.1 84.1 of which aromatics" II 50.8 49.8 i-paraffins "n 28.6 34.9 olefins""3, 8 6 residual sulfur "" 0.32 0.21
The above examples show that a catalyst system according to the invention is distinguished from a common FCC catalyst by:
- improved selectivity in the formation of fuels, with practically equal activity;
- significantly reduced formation of gas and coke;
- a significantly better yield in aromatic products;
-a significantly greater decomposition of sulfur products.

Claims (6)

1- Catalyst systems for cracking high-boiling hydrocarbon fractions, containing as main compound a mixture of aluminosilicates which are on the one hand crystallized, modified by ion exchange, on the other hand with an amorphous structure to the rays X, largely free of alkalis, systems characterized in that they contain - zeolitic aluminosilicates, preferably of the NaJ type, in which the Na + ions have been exchanged up to 60 to 95% equivalent by hydrogen, ammonium cations and / or cations of the 2nd and / or 3rd main groups and / or sub- groups of the periodic system of elements, in a proportion of 1 to 50 * by mass, - an aluminosilicate of amorphous structure to X-rays, with an Na20 content of at least 0.03 * by mass and an SiO2 content of 1 to 90% by mass, calculated on the material calcined at 1073K, in a proportion of 5 to 90 * year mass, - optionally a peptizable binding agent, in a proportion of 1 to 30% by weight, - One or more heavy metal compounds, of the 6th group of the periodic system deposited on an oxidized support, in a proportion of 0.1 to 20% by mass. This oxidized support comprises 1 to 10% by mass of one or more compounds of an element of the first or of the second main group of the periodic system of the elements, in a proportion of 0.1 to 20% by mass. 2- Catalyst systems according to claim 1, characterized in that they contain from 5 to 25% by mass of zeolitic aluminosilicates, 10 to 80% by mass of amorphous aluminosilicates to X-rays, 10 to 25% by mass of Boehmite hydrogel as a peptizable binder, and 1 to 10% by mass of heavy metal compounds on an oxidized support. 3- Catalyst systems according to one of claims 1 and 2, characterized in that the oxidized support contains aluminum oxide, silicon dioxide or aluminosilicate, and that, as elements of the 1st and 2nd groups main elements of the Periodic Table of Elements, potassium, cesium, calcium or magnesium are used. 4- Catalyst systems according to one of claims 1 or 2, characterized in that as heavy metal compounds, the oxides and / or sulphides of molybdenum and / or tungsten are used, in proportions of 1 to 10 * by weight. 5- Catalyst systems according to any one of claims 1 to 4, characterized in that they consist of microspheric particles with a diameter of 10 to iso) U. 6- Catalyst systems according to any one of claims 1 to 4, characterized in that, from the oxidized support and the heavy metal compound, as well as the compounds mentioned above, microspherical particles of 10 to 120 fut are separately prepared. of diameter; the mechanical mixtures of which can be used, in a ratio of 0.01 to 1, for cracking into high-boiling point hydrocarbon fractional fuels.