FR2623814A2 - Catalyst for cracking hydrocarbon feedstocks comprising an offretite, a zeolite and a matrix - Google Patents

Abstract

Process for catalytic cracking in the presence of a catalyst based on a zeolite and an offretite which are diluted in a matrix. The catalyst employed in the process contains in particular: a) from 20 to 95 % by weight of at least one matrix, b) from 1 to 70 % by weight of at least one zeolite with open structure in which the opening of the main channels is at least 7 x 10<-10> m, c) from 0.05 to 40 % by weight of at least one offretite in which the opening of the main dodecagonal channels is smaller than 6.8 x 10<-10> m, which has an SiO2/Al2O3 molar ratio of approximately 15 to approximately 500, elementary crystal lattice constants a and c of approximately 1.285 to 1.315 nm in the case of a and approximately 0.748 to 0.757 nm in the case of c, respectively, and a potassium content lower than 1.5 % by weight. The process makes possible an appreciable increase in the octane number of the petrol produced by cracking.

Description

The present application for an addition patent falls within the scope of the catalytic cracking in the fluid state of hydrocarbon feedstocks. It relates to the use of a catalyst described in the main French patent application No. 87-01802 of February 11, 1987 and which here undergoes various modifications with a view to better adaptation to catalytic cracking.

It is known that the petroleum industry routinely uses cracking processes, in which high molecular weight, high boiling hydrocarbon molecules are split into smaller molecules, which boil in lower temperature ranges. , suitable for the intended use.

The process most commonly used for this purpose, at the present time, is the process known as catalytic cracking in the fluid state (in English, Fluid Catalytic Cracking, or alternatively FCC process). In this type of process, the hydrocarbon feed is vaporized by bringing it into contact at high temperature with a cracking catalyst, which is kept in suspension in the feed vapors. After having reached by cracking the desired molecular weight range, with a corresponding lowering of the boiling points, the catalyst is separated from the products obtained, stripped, regenerated by combustion of the coke formed, then brought back into contact with the feedstock. to crack.

In new FCC processes, two regeneration zones can be used through which the spent catalyst circulates.

The charges to be cracked are usually injected into the reaction zone at a temperature generally between 480 ° C. and 540 ° C., under a relative pressure of 0.7 to 3.5 bar, while the temperature of the regenerated catalyst which arrives in this zone can be in the range of 600 to 950 C.

The catalyst is introduced at the base of an elevator of the ascending type (or "riser") in an amount determined for example by the opening or closing of a valve. The catalyst grains are then conditioned and accelerated to the top of the "riser" by injection at the base of the latter, of a gaseous fluid.

This injection is made using a fluid dispenser. The feed to be cracked is introduced at a higher level and at least partially vaporized with the aid of a suitable device in the dense flow of catalyst grains.

The "riser" emerges at its top in an enclosure which is for example concentric with it and in which the separation of the cracked feed is carried out, on the one hand, and, on the other hand, the stripping of the used catalyst. The catalyst is separated from the effluent, driven by a cyclonic system, then purified and purified.

The hydrocarbon feeds capable of being injected into units of the type described above may contain hydrocarbons having boiling points between 200 and 550 "C or more, and their density may vary between 10 and 35" API. These charges also, can be heavy charges containing hydrocarbons whose boiling point can go up to 7500C and more, and whose density can vary between 10 and 35 "API, even between
O and 25 "API.

For example, there may be mentioned as feeds, those having final boiling points of the order of 400 "C, such as vacuum gas oils, but also heavier hydrocarbon oils, such as crude and / or stabilized oils. , and residues from atmospheric distillation or vacuum distillation; these feeds may, where appropriate, have received a prior treatment such as, for example, a hydrotreatment in the presence for example of catalysts of the cobalt-molybdenum or nickel-molybdenum type.

These feeds may or may not be diluted by cuts of hydrocarbons which have already undergone the cracking operation, which are recycled, such as, for example, light recycling oils ("light cycle oil", LCO) and / or heavy oils from recycling ("heavy cycle oil", HCO) and / or the heaviest untransformed fraction generally boiling above 500 "C or 550" C and commonly called "slurry". According to the preferred embodiment of the invention, these charges are available and preheated in a temperature range of between 300 and 450 ° C. before their treatment.

The present addition relates to a catalytic cracking process using a particular catalyst which makes it possible to improve the flexibility on the structure of the product yields and the quality of the gasoline cut, that is to say the research and driving octane numbers of this. last.

It is recalled that in general, in the field of catalytic cracking, the implementation of the process depends in particular on the nature of the hydrocarbon effluents that the user wishes to obtain as a function of the refining objectives at the time, as well as generally. catalytic cracking of an oil makes it possible to obtain - light gases (hydrogen, hydrocarbons with 1 and 2 atoms of
carbon per molecule), - propylene, - propane (C3), - saturated hydrocarbons with 4 carbon atoms per molecule (C4
saturated and iso C4), - unsaturated hydrocarbons with 4 carbon atoms, - gasolines, - a relatively light oil or light diluent ("light cycle oil" or "LCO"), - a relatively heavy oil or heavy diluent (" heavy cycle oil "or" HCO "), - a residue or" slurry "which is generally purified - from the catalyst
trained to obtain a clarified oil or
CO) or a decanted oil ("Decanted oil or DO).

It may happen that an objective of refining in the context of catalytic cracking, is to obtain an increased quantity of liquefied petroleum gas (C3-C4 or LPG) and more particularly an increased quantity of propylene or even butenes. and / or isobutane. Moreover, it is well known that the general tendency is to reduce the content of lead-based additive in the gasolines constituting automobile fuels and that this will require the manufacture of gasolines, in particular by catalytic cracking, having octane numbers. clear search and improved engine Some users seek to either significantly increase the production of unsaturated C3 (propylene) without increasing the production of C4 hydrocarbons and saturated dry gases (H2, C1,
C2), either to significantly improve the production of unsaturated C3 (propylene) and iso C4 without significantly increasing the production of saturated dry gases (H2, C1, C2), or to significantly increase the production of unsaturated C3 (propylene) and optionally C4, in particular unsaturated, without increasing the production of saturated dry gases (H2, C1, C2). In all 3 cases, it is most often sought to combine it with a maximum production of gasoline with a particularly high octane number. These are the last 2 possibilities and the increase in octane which are sought in the present patent application and which can be obtained by the use of a new specific catalyst for catalytic cracking.

The process of the present invention in fact makes it possible to simultaneously achieve several of these objectives, in particular a notable improvement in the quality of the gasoline and an increase in the yields of propylene butenes and isobutane.

The process of the present invention consists in adding to the base catalyst, which contains at least one zeolite of faujasite structure (X or Y zeolites), a small amount of a zeolite with a main pore opening smaller than that of faujasite. , less than 7 x 10 10 m and for example between 0.60 and 0.68 nm.

Among the zeolites capable of making it possible to obtain a catalyst capable of improving the yields of light products with 3 and 4 carbon atoms and in particular of propylene, butenes and isobutane and above all of increasing very significantly, the indices d octane research and engine of gasoline (RON and MON), it was surprisingly discovered that zeolites of the erionite family, such as erionite ,offretite, or zeolites related to the latter such ZSM-34 or AG2 zeolites,
NO, ZKU or even zeolites made up of mixed crystals of erionite and offretite (erionite T for example) have these properties, thus making it possible to obtain yields of propylene, butenes and isobutane and octane numbers of l. 'gasoline clearly superior to those which can be obtained with conventional zeolitic cracking catalysts, especially when they are used as an additive to the latter. Among these zeolites of the erionite family, it has also been discovered that the stabilized and dealuminated offretites, characterized in particular by a silica to alumina molar ratio of greater than or equal to 15, make it possible to obtain particularly high-performance catalysts.

One of the preferred zeolites of the present invention is stabilized dealuminated offerite. It is obtained using modifying treatments which allow the aluminum and silicon composition of its aluminosilicate framework to be adjusted at will. Its preparation has been described in European patent application EP-A-190949.

In the present invention, we have used zeolites of the modified acid offretite type to prepare a catalyst for cracking hydrocarbon feeds, allowing to obtain an improved quality (higher octane numbers of gasoline) and an improved production of hydrocarbons. with 3 and 4 carbon atoms per molecule and in particular of propylene, and of butenes and isobutane.

Offenderite is a natural or synthetic zeolite, belonging to the chabazite group. Its structure has long been considered identical to that of erionite, a zeolite of the same family, by the similarities of their X-ray diffraction spectra (HEY MH & FEJER EE, Min. Mag. 33, 66, 1962). However, these two structures are different: on the one hand, the hexagonal mesh of theoffretite has a dimension along the c axis which is half that of erionite (BENNETT JM & GARD JA, Nature 214, 1005, 1967), and thus, the odd 1 lines present in the X-ray diffraction spectra of erionite (GARD JA & TAIT JM, Molecular Sieves
Zeolites-1, Advan. Chem.Ser. 101, 230, 1971); on the other hand, the stacking sequences in the two zeolites are different (WHYTE TT Jr, WU EL, KERR GT & VENUTO PB, J. Catal. 20, 88, 1971). Offerite thus has a much more open structure than erionite. Stacking faults can occur in these structures, giving rise to the formation of erionite T which is a zeolite of offretite structure with erionite-type stacking faults.

The structure of theoffretite has been clarified by many authors and in European Patent No. 190949. This European patent describes theoffretite used in the present invention, describes its means of characterization and its preferred methods of manufacture.

The catalyst used in the present invention contains a mixture of a matrix, of a zeolite with an open structure, the definition of which will be given below, and of a zeolite of the erionite family. Such a catalyst can be prepared by any methods well known to those skilled in the art. Thus it can be obtained by simultaneous incorporation of the zeolite of the erionite family and of the zeolite of open structure in the matrix according to the conventional methods for preparing cracking catalysts containing a zeolite. The catalyst can also be obtained by mixing mechanics of a product comprising a matrix and a zeolite of open structure (see below for the definition of the open structure) such as for example a Y zeolite, and of a product comprising the zeolite of the erionite family , for example, the offerite described above which is for example a mixture of said zeolite with a matrix.

The matrix-zeolite mixture of open structure employed in the preparation of the catalyst of the present invention is generally a conventional cracking catalyst according to the prior art (for example a commercial catalyst). The zeolite can be an X, beta, omega zeolite, and more particularly a Y zeolite, in particular ultrastable Y zeolites, enriched for example with at least one metal of the rare earth family or new Y zeolites enriched in silica by treatments. chemicals, called LZ210 and described in particular in US Patents 4,503,023 and 4,534,853, EP. 0.139.291 and 0.124.120 ;; the zeolite of the erionite family, for example an offrètite, described above which is used to manufacture the catalyst of the invention can then be considered as an additive which can be used as such in view of its mixture with the conventional cracking catalyst defined above or be incorporated beforehand in a matrix, the matrix-offretite assembly (for example) then constituting the additive which is mixed with the conventional cracking catalyst defined above, by example- after adequate shaping, by mechanical mixing of the grains containing, for example, offeretite and grains of conventional cracking catalyst.

Although all the zeolites of the erionite family, in particular groupite, or ZSM34, or the zeolites AG2, NO or ZKU or else the erionite T, can be suitable for the present invention, it has been discovered that the most efficient catalysts for the selective production of propylene contained offretites strongly enriched in silica. More precisely, these offretites have the. following characteristics - SiO 2 / Al 2 O 3 molar ratio greater than about 15 and preferably
greater than about 20 (especially between 15 and 500 and more
particularly between 20 and 300), - crystalline parameters a and c respectively included for a between
about 1.285 to about 1.315 nm and preferably between about
1.290 and about 1.310 nm, for c between about 0.748 and about
0.757 nm, - potassium content less than 1.5% by weight and preferably less than
0.5% by weight, and with further - nitrogen adsorption capacity at 77 K and at a P / Po ratio of 0.19,
greater than 0.15 cm3 liquid per gram and preferably at
0.20 cm3 liquid per gram, - adsorption capacity of cyclohexane at 25 C and at a P / Po ratio
0.25, greater than 3 and preferably 4% by weight, - water adsorption capacity, at 25 C for a P / Po ratio of 0.1
less than 15% and preferably less than about 10% in
weight, and preferably with the existence of a secondary microporosity, measured by the BJH method (defined in EP N 190 949), located between 3 and 5 nm and corresponding to approximately 5 to 50% of the total pore volume of the zeolite.

It also goes without saying that the modifying treatments known for offeritis can be applied to all structures of the erionite-offretite type and in particular to zeolite.
ZSM-34, and with zeolites AG-2, NO, ZKU and erionite T.

The catalyst used in the present invention contains a) from 20 to 95% and preferably from 30 to 80% and in a manner
often advantageous from 50 to 80% by weight of at least one matrix
(component A); b) from 1 to 70% and preferably from 4 to 60% and often
advantageous from 10 to 50% by weight of at least one zeolite of
open structure other than a zeolite of the family of
erionite (constituent B);. the term structural zeolite
open designates in the present invention a zeolite whose
the opening of the main 12-sided channels has one dimension
such that it is equivalent to a circular opening having a
diameter of at least 7 Angtroms (7 x 10 10 m); c) from 0.05 to 40% and preferably from 0.1 to 30%, and in a manner
often advantageous from 0.5 to 10% by weight, of at least one
zeolite from the erionite family (offretite, ZSM34, AG2, NO, ZKU ,.

or erionite T for example) having a potassium content
less than 4% by weight, the total content of alkali metals
preferably being less than 4% by weight (component C).

The sum of the percentages by weight of constituents A, B and
C contained in the catalysts is equal in each case to 100%.

In the case where the zeolite of the erionite family is added to the main catalyst in the form of spherical particles separated from the latter but of the same particle size as the latter, the weight of the zeolite of the erionite family is between 1 and 90% (preferably 5 and 60%) relative to the weight of said particles (other than those of the main catalyst).

Component A comprises at least one matrix generally chosen from the group formed by alumina, silica, magnesia, clay, titanium oxide, zirconia, the combinations of at least two of these compounds and the combinations alumina-boron oxide.

Component B comprises at least one zeolite of open structure, having dodecagonal channels of at least 7
Angstroms (7 x 10-10 m) opening, generally chosen from the group formed by X, Y, L, omega and beta zeolites. The zeolites of faujasite structure and in particular the Y zeolites, preferably stabilized, commonly called ultrastable or USY, or enriched in silica such as the LZ210 zeolite described in US Patents 4,403,023 and 4,534,853, EP, are preferably used. O 139.291 and 0.124.120, either in the form at least partially exchanged with cations of alkaline earth metals and especially with cations of rare earth metals of atomic number 57 to 71 inclusive, or in hydrogen form.

Component C of the catalyst according to the invention is preferably based on at least one offretite, the opening of the main dodecagonal channels of which is less than 6.8 x 10 10 m (6.8
Angstroms), (component C) having a SiO2 / A1203 molar ratio of about 15 to about 500, crystal parameters a and c of the unit cell of about 1.285 to 1.315 nm for and about 0.748 to 0.757 nm for, respectively r, and a potassium content of less than 1.5% by weight, the total content of alkali metals preferably being less than 1.5% by weight.

In the present invention, the offerite can be used in the hydrogen form, therefore containing practically no metal cation apart from the very small quantity of alkali metal cations (potassium in particular) which are residual cations resulting from the synthesis of the zeolite. Thenetite can also be used in the form at least partially exchanged by multivalent metal cations; part of the cationic sites of the alumino-silicate framework is then occupied by these cations; such cations are for example cations of alkaline earth metals and preferably cations of rare earth metals of atomic number 57 to 71 inclusive and more especially lanthanum; these cations are intended to block the structural evolution of the particular offerite employed which indeed risks occurring under the severe conditions of the regenerator of the industrial cracking unit.

The offretite used in the present invention is an offretite whose alumino-silicate framework consists only of aluminum atoms and silicon atoms; however, it is also possible to use an offretite as described above in which part of the aluminum and / or silicon of the aluminosilicate framework is replaced, at the end of the synthesis, by other elements, metals or metalloids , such as for example
B, P, Ti, V, Cr, Fe, Mn, Ga, Ge and Zr.

The general conditions of catalytic cracking reactions are particularly well known so as not to be repeated here in the context of the present invention (see for example USP 3,293,192; 3,449,070; 4,415,438; 3,518,051 3,607,043).

The following examples illustrate the present invention without limiting its scope.

EXAMPLE 1 Preparation of an OFF1 offretite with a molar SiO 2 / Al 2 O 3 ratio equal to 52.

1200 g of a synthetic offretite with an opening of the main dodecagonal canals of 6.4 x 10-10 m, (W. MEIER and
DH OLSON, Atlas of Zeolite Structure Types, 1978) with a Si02 / A12O3 molar ratio equal to 8, containing 9.9% by weight of potassium and 2.8% by weight of tetramethylammonium ions, were calcined at 550 C under a mixture of 80% nitrogen and 20% air (total flow 3 1h-1) for one hour then in pure air (flow 3 1h-1g-1) for one hour so as to remove the TMA + cations.

The product obtained was then exchanged three times with a 2M solution of ammonium nitrate, at 100 ° C. for 4 hours, with stirring, with a volume of solution to weight of dry solid (V / P) ratio equal to 5 cm3g- 1.

The solid obtained at the end of these treatments and reference 1A contains 2.8% by weight of potassium and its molar ratio
SiO2 / A1203 is 8. Its diffraction pattern is shown in Table 1.

The opening of the main dodecagonal ducts of the offeretitis was not modified by the treatments.

Solid 1A is subjected to the following successive treatments - self-steaming at 5500C for 2 hours (obtaining product 2A), - 2 successive cation exchanges in a 2M NH4 NO3 solution,
at 100 C for 4 hours with stirring with a volume ratio of
solution on dry solid weight (V / P) equal to cm3 g-1 - self-steaming at 650 C for 2 hours, - 2M NH4NO3 at 100 C for 4 hours with stirring with a ratio
volume of solution by weight of dry solid (V / P) equal to 5 cm3g-1, - 1 acid attack in 1N HCl at 100 C for 2 hours with a
ratio volume of solution to weight of dry solid equal to 15
cm3g-1.

cristallinité (DX)....................91 %
Volume microporeux N2................. 0.28 cm3 g-1
Capacité d'adsorption d'eau (% pds)... 3 %
Capacité d'adsorption de
cyclohexane.(% pds)................ 7.1 %
Comme l'indiquent les caractéristiques précédentes, le solide OFF1 est une offrètite désaluminée de rapport SiO2/A1203, égal à 52, bien cristallisée-, à très faible teneur résiduelle en potassium et dont le volume microporeux est élevé.This then leads to the solid referenced OFF1, the characteristics of which are as follows
(SiO2 / Al2O3) mole ............. 52
% K .......................... 0.13% weight parameters a, l3.01 A crystalline c> 7.53

crystallinity (DX) .................... 91%
Microporous volume N2 ................. 0.28 cm3 g-1
Water adsorption capacity (wt%) ... 3%
Adsorption capacity of
cyclohexane. (wt%) ................ 7.1%
As indicated by the preceding characteristics, the solid OFF1 is a dealuminated offrètite of SiO2 / A1203 ratio, equal to 52, well crystallized-, with very low residual potassium content and of which the microporous volume is high.

TABLE 1
X diffraction pattern of product 1A

<tb> 2 <SEP> theta <SEP> d <SEP> (nm) <SEP> Intensity <SEP> 2 <SEP> theta <SEP> d (nm) <SEP> Intensity <SEP>
<tb> 7.10 <SEP> 1.145 <SEP> 66 <SEP> 28.10 <SEP> 0.317 <SEP> 10 <SEP>
<tb> 11.75 <SEP> 0.752 <SEP> 7 <SEP> 28.40 <SEP> 0.314 <SEP> 24
<tb> 13.40 <SEP> 0.661 <SEP> 37 <SEP> 30.55 <SEP> 0.292 <SEP> 5 <SEP>
<tb> 14.10 <SEP> 0.268 <SEP> 7 <SEP> 31.25 <SEP> 0.286 <SEP> 62
<tb> 15.50 <SEP> 0.572 <SEP> 18 <SEP> 31.50 <SEP> 0.284 <SEP> 59
<tb> 17.85 <SEP> 0.496 <SEP> 2 <SEP> 33.50 <SEP> 0.267 <SEP> 24
<tb> 19.50 <SEP> 0.455 <SEP> 26
<tb> 20.50 <SEP> 0.433 <SEP> 54
<tb> 23.31 <SEP> 0.382 <SEP> 31
<tb> 23.70 <SEP> 0.375 <SEP> 100
<tb> 24.90 <SEP> 0.357 <SEP> 66 <SEP>
<tb> 26.20 <SEP> 0.340 <SEP><<SEP> 1 <SEP>
<tb> 27.00 <SEP> 0.330 <SEP> 23
<tb> 27.30 <SEP> 0.327 <SEP> 7
<tb>
EXAMPLE 2 Preparation of an offretite OFF2 with a molar SiO2 / A1203 ratio equal to 105.

The product referenced OFF1 of Example 1 is used as the starting base. This product is subjected to the following treatments - self-steaming at 7500C for 2 hours, - acid attack in 3N HCl at 100 C for 4 hours with a ratio
volume of solution by weight of dry solid (V / P) equal to 15 cm3g 1.

This leads to the solid reference OFF2, which has the following characteristics SiO2 / A1203) 103% K .............................. 0.04 % weight

<tb> parameters <SEP>(<SEP> a <SEP> 12.97 <SEP> A0 <SEP><SEP> I &num;,%)
<tb> crystallinstc <SEP>. <SEP> 7.54 <SEP><SEP>(<SEP> ot7.54 <SEP> A
<tb>
Crystallinity (DX) 87%
Microporous volume N2 ............ 0.27 cm3g-1
Water adsorption capacity 1.1%
(% wt)
6.8% adsorption capacity
cyclohexane
Like the solid OFF1, OFF2 is a very dealuminated offrètite, with a SiO2 / Al203 molar ratio = 105, well crystallized, with a low residual potassium content and with a high microporous volume.

EXAMPLE 3 (not in accordance with the invention): carried out on a reference industrial balanced catalyst (Cat E).

A catalytic cracking test is carried out using a hydrocarbon feed, the characteristics of which are shown in Table 2. The balanced industrial catalyst used (called Cat E) contains 70% of a conventional matrix based on a silica alumina rich in silica and kaolin and contains 30% of an ultrastable Y zeolite USY. It has the following characteristics
surface in m2.g-1 = 110
rare earth oxide in% weight = 1.6
Na20% wt = 0.3
V (ppm) = 4800
Ni (ppm) = 2800
Fe (ppm) = 10200.

This Cat E catalyst is placed in the reactor of a micro-test unit (also called MAT unit "Microactivity Test
Unit ") and brought into contact with the hydrocarbon feed under the following test conditions T = 520 C
C / O = 5 to 6.5 (*)
amount of catalyst: 5 g
injection duration: 40 seconds.

The research and engine octane numbers of light gasoline and heavy gasoline are calculated from detailed chromatographic analyzes of the C5 liquid effluent collected at the outlet of the reactor at the end of the catalytic test.

The results are shown in Table 3.

(*) In all the examples which follow, the value of the C / O ratio
will be calculated taking into account only the catalyst of
reference and therefore without taking into account the possible presence
of an additive. In other words: C = weight in grams of the
Cat E reference catalyst.

TABLE 2
Characteristics of the heavy load used
Density (20 C) 0.968
Viscosity (solid at 6O0C)
(80 C) 119.8 cSt (100 C) 52.2
Conradson% weight 5.1

Na ppm 2
Ni ppm 12
V ppm 1
C% weight 86.9
H% weight 12.2
N% weight 0.35
S% weight 0.21
N basic% weight 0.055
C aromatic% weight 22.3
Aromatic H% weight 2.7
Simulated distillation (C) 5% weight 367 10% weight 399 20% weight 436 40% weight 495 60% weight 575
FBP 575
TABLE 3

<tb> Catalyst <SEP> Cat <SEP> E
<tb> n <SEP> test <SEP> 1 <SEP> 2 <SEP> 3
<tb> C / O * <SEP> 5.0 <SEP> 5.5 <SEP> 6.5 <SEP>
<tb> (% <SEP> weight) <SEP>
<tb> Conversion <SEP> 62.36 <SEP> 69.69 <SEP> 73.60
<tb> j <SEP> C1-C4 <SEP> 1 <SEP> 12.75 <SEP> 1 <SEP> 16.63 <SEP> 1 <SEP> 17.98 <SEP> | <SEP>
<tb> j <SEP> Ess <SEP> (C5-150) <SEP> t <SEP> 30.22 <SEP> 1 <SEP> 33.39 <SEP> 1 <SEP> 32.93 <SEP> | <SEP>
<tb> ss <SEP> Ess <SEP> (150-221) <SEP> ss <SEP> 11.13 <SEP> 1 <SEP> 11.63 <SEP> 1 <SEP> 10.49 <SEP> | <SEP>
<tb> | <SEP> Total <SEP> gasoline <SEP> 1 <SEP> 41.35 <SEP> 1 <SEP> 45.02 <SEP> 1 <SEP> 43.42 <SEP> | <SEP>
<tb> | <SEP> LCO <SEP> (221-350) <SEP>;<SEP> 15.68 <SEP> 1 <SEP> 14.45 <SEP> 1 <SEP> 12.50 <SEP> | <SEP>
<tb> Slurry <SEP> (350+) <SEP> 21.97 <SEP> 15.86 <SEP> 13.90
<tb> | <SEP> Coke <SEP> 1 <SEP> 7.75 <SEP> 1 <SEP> 7.54 <SEP> 1 <SEP> 11.67 <SEP> 1 <SEP>
<tb> | <SEP> H2 <SEP> 1 <SEP> 0.51 <SEP> 1 <SEP> 0.50 <SEP> 1 <SEP> 0.54 <SEP> | <SEP>
<tb> C1 <SEP> 0.57 <SEP> 0.66 <SEP> 0.68
<tb> C2 <SEP> 0.45 <SEP> 0.47 <SEP> 0.49
<tb> j <SEP> C2 = <SEP> 1 <SEP> 0.60 <SEP> 1 <SEP> 0.77 <SEP> 1 <SEP> 0.84 <SEP> | <SEP>
<tb> ss <SEP> C2 <SEP> totals <SEP> 1 <SEP> 1.05 <SEP> 1 <SEP> 1.24 <SEP> 1 <SEP> 1.33 <SEP> | <SEP>
<tb> g <SEP> C3 <SEP> g <SEP> 0.63 <SEP> 1 <SEP> 1.02 <SEP> 1 <SEP> 1.18 <SEP> | <SEP>
<tb> j <SEP> C3 = <SEP> | <SEP> 3.20 <SEP> 1 <SEP> 3.82 <SEP> 1 <SEP> 4.10 <SEP>
<tb> C3 <SEP> totals <SEP> 3.83 <SEP> 4.84 <SEP> 5.28
<tb> 1 <SEP> iC4 <SEP> 1 <SEP> 1.56 <SEP> 1 <SEP> 2.92 <SEP> 1 <SEP> 3.36 <SEP> | <SEP>
<tb> | <SEP> nC4 <SEP> 1 <SEP> 0.49 <SEP> 1 <SEP> 0.85 <SEP> 1 <SEP> 0.98 <SEP> | <SEP>
<tb> iC4 = <SEP> 1 <SEP> 1.77 <SEP> 1 <SEP> 1.94 <SEP> 1 <SEP> 2.03 <SEP> | <SEP>
<tb> nC4 <SEP> 1 <SEP> 3.47 <SEP> 1 <SEP> 4.17 <SEP> 1 <SEP> 4.32 <SEP> | <SEP>
<tb> | <SEP> C4 <SEP> totals <SEP> 1 <SEP> 7.29 <SEP> 1 <SEP> 9.88 <SEP> 1 <SEP> 10.69 <SEP> | <SEP>
<tb> | <SEP> RON <SEP> ess <SEP> light <SEP> 1 <SEP> 92.4 <SEP> 1 <SEP> 92.8 <SEP> 1 <SEP> 93.3 <SEP> | <SEP>
<tb> RON <SEP> ess <SEP> heavy <SEP> 88.6 <SEP> 88.9 <SEP> 89.4
<tb> t <SEP> MON <SEP> ess <SEP> light <SEP> 1 <SEP> 77.9 <SEP> 1 <SEP> 78.3 <SEP> 1 <SEP> 78.5 <SEP> | <SEP>
<tb> MON <SEP> ess <SEP> heavy <SEP> 79.2 <SEP> 79.5 <SEP> 79.9
<tb> in C / O, C = weight of Cat E catalyst.

EXAMPLE 4 Preparation of the offerite-based cracking additives prepared in the preceding examples.

The two products OFF1 and OFF2 obtained in Examples 1 and 2 are respectively diluted in an amount of 30% by weight, in an amorphous silica of particle size comparable to that of the offretites used.

The two catalytic additives thus obtained are pelletized and then reduced into small aggregates using a crushing machine.

The fraction between 40 microns and 200 microns is then collected by sieving. These two additives obtained are mixed mechanically in a conventional manner in an amount of 6.7% or 16.7% by weight with the balanced industrial catalyst for catalytic cracking called in abbreviated form Cat E. The catalysts which result from these mixtures thus respectively contain 2% by weight or 5% by weight of OFF1 or OFF2 offretites.

EXAMPLE 5 (according to the invention):
Two catalysts made up of the following mechanical mixtures of the above Cat E catalyst and the additive containing the OFF 1 offender (SiO2 / Al2O3 = 52) are studied under the same conditions and with the same load as previously (example 3).
Cat E + 2% wt OFF1 and Cat E + 5% wt OFFI.

The results obtained are presented in table 4 (*).

They highlight the following main points in all cases the propylene yields are very clearly
improved, in all cases the search and engine octane numbers are
markedly improved, in all cases, the yields of gasoline, light diesel (LCO)
and heavy fraction HCO + slurry are lower, in test 4 of example 5 (table 4), the differences
of octane number and gasoline yield compared to the test
1 of example 3 above are
Gasoline yield = -3.89
RON light gasoline = + 1.8
RON heavy gasoline = + 8.9
MY light gasoline = + 3.6
MY heavy gasoline = + 5.2
Propylene yield = + 3.31 (i.e. 3.31 / 3.20 = 103% or more of the double)
Isobutane yield = + 2.40 (i.e. 2.40 / 1.56 = 154%)
Yield n butenes = + 2.0 (i.e. 2 / 3.47 = 58%).

These examples show that the addition of small amounts of boxite or conventional cracking catalyst significantly improves the quality of gasoline and the production of propylene and isobutane and, to a lesser extent, normal butenes.

EXAMPLE 6 (according to the invention)
A new catalyst consisting of the following mixture of the previous Cat E catalyst and the additive containing offerite
OFF2 (SiO2 / Al2O3 = 105) is studied under the same conditions and with the. same load as previously (examples 3 and 5):
CAT E + 5% by weight OFF2 (*) Remember that for all these results, the C / O value is equal to the weight of the Cat E reference catalyst.

TABLE 4

<tb> Cat <SEP> E +
<tb> Catalyst
<tb> 2 <SEP>% <SEP> pds <SEP> OFF1 <SEP> 5 <SEP>% <SEP> pad <SEP> OFF1
<tb> n <SEP> test <SEP> 4 <SEP> 5 <SEP> 6 <SEP> 7 <SEP> 8
<tb> C / O <SEP> (*) <SEP> 5.0 <SEP> 5.4 <SEP> 4 <SEP> 4.8 <SEP> 5.5
<tb> (% <SEP> weight)
<tb> Conversion <SEP> 1 <SEP> 68.89 <SEP> 1 <SEP> 71.36 <SEP> 1 <SEP> 60.99 <SEP> 1 <SEP> 68.47 <SEP> 1 <SEP > 73,1P <SEP> 1- <SEP>
<tb> C1-C4 <SEP> 1 <SEP> 23.29 <SEP> 1 <SEP> 26.08 <SEP> 1 <SEP> 23.91 <SEP> 1 <SEP> 27.62 <SEP> 1 <SEP> 33,26 <SEP> | <SEP>
<tb> | <SEP> Ess <SEP> (C5-150) <SEP> t <SEP> 28.41 <SEP> 1 <SEP> 27.56 <SEP> 1 <SEP> 24.01 <SEP> 1 <SEP> 24 , 63 <SEP> | <SEP> 23.07 <SEP> | <SEP>
<tb> | <SEP> Ess <SEP> (150-221) <SEP> 1 <SEP> 9.04 <SEP> 1 <SEP> 9.00 <SEP> 1 <SEP> 6.26 <SEP> 1 <SEP> 7 , 03 <SEP> 1 <SEP> 6.19 <SEP> | <SEP>
<tb> | <SEP> Gasoline <SEP> total <SEP> 1 <SEP> 37.46 <SEP> 1 <SEP> 36.56 <SEP> 1 <SEP> 30.27 <SEP> 1 <SEP> 31.66 <SEP > 1 <SEP> 29,27 <SEP> | <SEP>
<tb> LCO <SEP> (221-350) <SEP> 1 <SEP> 13.38 <SEP> 1 <SEP> 12.01 <SEP> 1 <SEP> 11.26 <SEP> 1 <SEP> 11 , 90 <SEP> 1 <SEP> 10.87 <SEP> | <SEP>
<tb> j <SEP> Slurry <SEP> (350+) <SEP> 1 <SEP> 17.73 <SEP> 1 <SEP> 16.18 <SEP> 1 <SEP> 27.76 <SEP> 1 <SEP> 19.64. <SEP> 1 <SEP> 16.03 <SEP> | <SEP>
<tb> Coke <SEP> 7.75 <SEP> 8.73 <SEP> 6.47 <SEP> 8.81 <SEP> 10.11 <SEP>
<tb> H2 <SEP> 0.39 <SEP> 0.45 <SEP> 0.34 <SEP> 0.39 <SEP> 0.47 <SEP>
<tb> | <SEP> Cl <SEP> 0.54 <SEP> 1 <SEP> 0.57 <SEP> 1 <SEP> 0.43 <SEP> 1 <SEP> 0.56 <SEP> 1 <SEP> 0.56 <SEP> | <SEP>
<tb> C2 <SEP> i <SEP> 0.40 <SEP> 1 <SEP> 0.41 <SEP> 1 <SEP> 0.35 <SEP> | <SEP> 0.41 <SEP> 1 <SEP> 0.45 <SEP> | <SEP>
<tb> j <SEP> C2 = <SEP> 1 <SEP> 1.04 <SEP> 1 <SEP> 1.23 <SEP> | <SEP> 0.99 <SEP> 1 <SEP> 1.48 <SEP> 1 <SEP> 2.00 <SEP> | <SEP>
<tb> | <SEP> C2 <SEP> totals <SEP> 1 <SEP> 1.44 <SEP> 1 <SEP> 1.64 <SEP> 1 <SEP> 1.35 <SEP> 1 <SEP> 1.88 <SEP > 1 <SEP> 2.46 <SEP> | <SEP>
<tb> C3 <SEP> 1 <SEP> 1.48 <SEP> 1 <SEP> 1.96 <SEP> 1 <SEP> 1.46 <SEP> 1 <SEP> 2.11 <SEP> 1 <SEP > 3.37 <SEP> | <SEP>
<tb> j <SEP> C3 = <SEP> t <SEP> 6.51 <SEP> 1 <SEP> 7.21 <SEP> 1 <SEP> 6.20 <SEP> 1 <SEP> 7.37 <SEP> 1 <SEP> 8.53 <SEP> | <SEP>
<tb> | <SEP> C3 <SEP> totals <SEP> 1 <SEP> 7.99 <SEP> 1 <SEP> 9.17 <SEP> 1 <SEP> 7.65 <SEP> | <SEP> 9.48 <SEP> 1 <SEP> 11.90 <SEP> | <SEP>
<tb> iC4 <SEP> | <SEP> 3.96 <SEP> 1 <SEP> 4.54 <SEP> 1 <SEP> 3.33 <SEP> 1 <SEP> 4.79 <SEP> 1 <SEP> 5.80 <SEP> 1
<tb> nC4 <SEP> 1 <SEP> 1.12 <SEP> 1 <SEP> 1.32 <SEP> 1 <SEP> 1.06 <SEP> 1 <SEP> 1.41 <SEP> 1 <SEP > 2,04 <SEP> i <SEP>
<tb> iC4 = <SEP> 1 <SEP> 2.78 <SEP> 1 <SEP> 3.02 <SEP> 1 <SEP> 4.25 <SEP> 1 <SEP> 3.78 <SEP> 1 <SEP> 4.16 <SEP> | <SEP>
<tb> nC4 <SEP> 1 <SEP> 5.46 <SEP> 1 <SEP> 5.82 <SEP> 1 <SEP> 5.84 <SEP> 1 <SEP> 5.72 <SEP> 1 <SEP > 6.35 <SEP> 1
<tb> j <SEP> C4 <SEP> totals <SEP> 1 <SEP> 13.32 <SEP> 1 <SEP> 14.70 <SEP> 1 <SEP> 14.48 <SEP> 1 <SEP> 15 , 70 <SEP> 1 <SEP> 18.35 <SEP> 1
<tb> j <SEP> RON <SEP> ess <SEP> light <SEP> 1 <SEP> 94.2 <SEP> 1 <SEP> 95.6 <SEP> | <SEP> 96.0 <SEP> 1 <SEP> 97.5 <SEP> 1 <SEP> 98.5 <SEP> | <SEP>
<tb> RON <SEP> ess <SEP> heavy <SEP> 1 <SEP> 97.5 <SEP> 98.2 <SEP> 1 <SEP> 93.4 <SEP> 1 <SEP> 98.8 <SEP > 1 <SEP> 99.1 <SEP> | <SEP>
<tb> j <SEP> MON <SEP> ess <SEP> light <SEP> 1 <SEP> 81.5 <SEP> 1 <SEP> 82.1 <SEP> 1 <SEP> 80.8 <SEP> 1 <SEP> 82.3 <SEP> 1 <SEP> 82.1 <SEP> | <SEP>
<tb> MON <SEP> ess <SEP> heavy <SEP> 84.4 <SEP> 85.5 <SEP> 82.2 <SEP> 85.7 <SEP> 85.6
<tb> (*) in C / O, C is equal to the weight of the reference Cat E catalyst.

The results obtained are shown in Table 5.

Compared with the previous example n 4, the use of a strongly dealuminated offretite OFF2 with an Si / Al atomic ratio = 52.5 very higher than that of the offretite OFF1, results in a lower activity (conversion 65, 49 instead of about 68.5-69), lower propylene production (4; 79 instead of about 6.5 to 7%), lower isobutane production (3.14 instead of 4 to 4.5), higher gasoline production but with lower research and engine octane numbers.Nevertheless, when compared to those of Example 3, these results still clearly demonstrate the interest of this Offretite to improve the production of propylene, isobutane and butenes and to improve the research and engine octane ratings of gasoline.

Let us recall here again that for these results, the value C of the C / O ratio is equal to the weight of the reference catalyst Cat E.
TABLE 5

<tb> Catalyst <SEP> Cat <SEP> E <SEP> + <SEP> 5 <SEP>% <SEP> OFF2
<tb> n <SEP> test <SEP> 9
<tb> C / O <SEP> (*) <SEP> 4.9
<tb> (% <SEP> weight)
<tb> Conversion <SEP> 65.49
<tb> C1-C4 <SEP> j <SEP> 18.93 <SEP> l <SEP>
<tb> j <SEP> Ess <SEP> (C5-150) <SEP> 1 <SEP> 28.92 <SEP> l <SEP>
<tb> | <SEP> Ess <SEP> (150-221) <SEP> 1 <SEP> 9.72 <SEP> 1 <SEP>
<tb> j <SEP> Total <SEP> gasoline <SEP> 1 <SEP> 38.64 <SEP> 1
<tb> | <SEP> LCO <SEP> (221-350) <SEP> 1 <SEP> 13.91 <SEP> 1 <SEP>
<tb> Slurry <SEP> (350+) <SEP> ss <SEP> 20.37 <SEP> 1 <SEP>
<tb> Coke <SEP> 1 <SEP> 7.92 <SEP> 1 <SEP>
<tb> H2 <SEP> 0.51
<tb> C1 <SEP> 0.65
<tb> C2 <SEP> 0.49
<tb> C2 = <SEP> 1.09
<tb> C2 <SEP> totals <SEP> 1.58
<tb> C3 <SEP> 1.09
<tb> C3 = <SEP> 4.79
<tb> | <SEP> C3 <SEP> totals <SEP> 1 <SEP> 5.88 <SEP> 1 <SEP>
<tb> j <SEP> iC4 <SEP> 1 <SEP> 3.14 <SEP> 1
<tb> nC4 <SEP> 0.87
<tb> iC4 = <SEP> 2.12
<tb> t <SEP> nC4 <SEP> 1 <SEP> 4.69 <SEP> | <SEP>
<tb> C4 <SEP> totals <SEP> 10.82
<tb> RON <SEP> ess <SEP> light <SEP> 94.1
<tb> j <SEP> RON <SEP> ess <SEP> heavy <SEP> 1 <SEP> 93.8 <SEP> | <SEP>
<tb> 2 <SEP> MON <SEP> ess <SEP> light <SEP> 1 <SEP> 79.9 <SEP> 1 <SEP>
<tb> MON <SEP> ess <SEP> heavy <SEP> 82.1
<tb> (*) in C / O, it is equal to the weight of the reference cat E catalyst.

Claims (4)

CLAIM 1. Process for the catalytic cracking of a hydrocarbon feed in which the operation is carried out in the presence of a catalyst according to one of claims 1 to 8 of the main patent and which contains a) from 20 to 95% by weight of at least one matrix (component A), b) from 1 to 70% by weight of at least one zeolite of open structure other than a zeolite of the erionite family (component B) whose opening of the main 12-sided canals has a dimension such that it is equivalent to an opening circular having a diameter of at least 7 Angtroms (7 x 10-10 m), c) from 0.05 to 40% by weight, of at least one zeolite of the family erionite with a potassium content of less than 4% by weight, the total alkali metal content preferably being less than 4% by weight (component C). 2. The method of claim 1 wherein said component (C) is selected from the group consisting of erionite ,offretite, ZSM34, zeolites AG2, N-O and ZKU and erionite. T. 3. The method of claim 2 wherein the component (c) is predominantly made of offerite. 4. The method of claim 3 wherein said component C, of the catalyst is based on at least one offretite whose opening of the main dodecagonal channels is less than 6.8 x 10 10 m, has a SiO2 / Al203 molar ratio of about 15 to about 500, crystalline parameters ai and c of the elementary mesh respectively of approximately 1.285 to 1.315 nm for a and of approximately 0.748 to 0.757 nm for c, and a potassium content of less than 1.5% by weight, the said offretite also having - a SiO2 / A1203 molar ratio greater than about 15, - a nitrogen adsorption capacity of 77 K and a P / Po ratio of 0.19, greater than 0.15 cm3 liquid per gram and preferably at 0.20 cm3 liquid per gram, - an adsorption capacity of cyclohexane at 250C and at a ratio P / Po of 0.25, greater than 3 and preferably 4% by weight, - and a water adsorption capacity, at 25 C for a P / Po ratio of 0.1 less than 15% and preferably less than about 10% in weight.