Catalyst – solid sorbent – or support therefor: product or process – Zeolite or clay – including gallium analogs – And additional al or si containing component
Reexamination Certificate
2002-09-23
2004-04-06
Dunn, Tom (Department: 1725)
Catalyst, solid sorbent, or support therefor: product or process
Zeolite or clay, including gallium analogs
And additional al or si containing component
C502S064000, C502S065000, C502S073000, C502S077000, C502S079000
Reexamination Certificate
active
06716784
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
This invention belongs to the field of catalysts for catalytic cracking of hydrocarbons and more particularly to the sector of zeolitic catalysts.
STATE OF THE ART PRIOR TO THE INVENTION
Owing to the elimination of tetraethyl lead from gasolines, and to the possible future elimination of methyl tert butyl ether (MTBE) as an additive for gasolines, there is considerable interest in increasing the octane rating of each of the streams making up the final gasoline. Among these streams, the one coming from fluid catalytic cracking (FCC) represents on average terms a value close to 30% of the total. Owing to its relative importance, any increase occurring in the barrel octane rating of FCC gasoline has a considerable economic impact. The octane rating of gasoline produced in the FCC unit can currently be increased by modifying the operating conditions of the unit, such as for example increasing the temperature of the reactor. Nevertheless, this solution entails a major increase in gases and, in particular, in undesired dry gas, with the consequent loss of gasoline. Better results are obtained by using new catalyst compositions that include the use of zeolite mixtures. So, in the bibliography of patents (see for example, U.S. Pat. Nos. 3,758,403, 3,894,931, 3,894,933, 4,309,279, 4,309,279, 4,339,354 and 4,309,280, among others), as well as in the available literature (see for example: Biswas, J., and Maxwell, I. E., Applied Catalysis 58, 1-18 (1990); Dwyer, F. G. and Degnan, T. F., Studies in Surface Science and Catalysis 76, 499 (1993)), it has been demonstrated that an increase in the octane rating of FCC gasoline occurs when Y zeolite mixed with ZSM-5 is used in the same FCC catalysis particle, or when using a mixture of different particles in which some correspond to the conventional cracking catalyst which uses Y zeolite and other particles contain ZSM-5 zeolite. The use of ZSM-5 zeolite as an additive in FCC catalysts also leads to an increase in C
3
and C
4
olefins which are also of great interest from the commercial point of view (see for example, U.S. Pat. Nos. 3,758,403, 3,769,202, 3,894,931, 3,894,933, 3,894,934, 3,926,782, 4,309,280, 4,309,279, 437,458 and Buchanan, J. S., and Adewuyi, Y. G., Applied Catalysis: A General, 134, 247 (1996); Madon, R. J., Journal of Catalysis 129 (1), 275 (1991)).
Nevertheless, it is known (Studies in Surface Science and Catalysis, vol. 76, 499 (1993)) that the introduction of ZSM-5 zeolite has little or no influence on the total conversion and it also produces a diminution in the total quantity of gasoline produced.
It would be interesting from the point of view of both producing an increase in the barrel octane rating of gasoline and in increasing the yield of C
3
and C
4
olefins to find other zeolites which would also permit the feed to be converted with the minimum loss of gasoline. Numerous medium and large pore zeolites have been studied for this purpose. The use of MCM-22, Omega, L, mordenite and BEA zeolites can be highlighted (see for example: J. Catal. 165, 102 (1997); Stud. Surf. Sci. and Catal. 46, 115 (1989); U.S. Pat. No. 5,314,612, EP 489324, U.S. Pat. Nos. 474,292, 4,137,152, EP 350331, FR 2661621).
The present invention has the aim of overcoming the aforementioned drawbacks of catalytic materials found in the state of the art by means of zeolitic material based on a new zeolite known as ITQ-7 (Villaescusa, L. A., Factores directores de estructura en la sintesis de zeolitas en medio fluoruro. Doctoral thesis from the Polytechnic University of Valencia, Valencia, Spain (1999), (Angw. Chem. Int. Ed., 38, 1997 (1999)) in compositions suitable for FCC, and the use of those materials in catalytic cracking. The pore topology in ITQ-7 zeolite confers on it activity for converting FCC feeds, and also, both on its own and in combination with other zeolites, it enables it to produce a good barrel octane rating of the gasoline that is produced and a good yield of C
3
and C
4
olefins, with good yields of gasoline being obtained at the same time.
DESCRIPTION OF THE INVENTION
The present invention refers on the one hand to a catalytic composition for hydrocarbons cracking containing at least two zeolitic components of which at least one zeolitic component containing aluminium in its structure is selected from among ITQ-7 zeolites, intergrowths of ITQ-7 zeolites, ITQ-7 zeolites exchanged with rare earths, intergrowths of ITQ-7 zeolites exchanged with rare earths, and combinations of them.
In accordance with the invention, the first component can be present in a proportion of between 2 and 40% of the total weight of zeolitic components present in the composition, in particle form and/or embedded in a matrix, alone or in combination with other components.
In one design of the composition of the invention, the zeolitic components also consist of, as well as the first zeolitic component, at least a second zeolitic component selected from among faujasite zeolites, faujasite zeolites at least partially exchanged with rare earths, cracking catalysts based on faujasite and combinations of them, in which case the composition can, with respect to the total weight of zeolitic components, include 2-40% by weight of the first zeolitic component and 2-98% by weight of the second zeolitic component. In this case, the first zeolitic component can be embedded in a matrix stabilised with phosphorus in which the weight of the first zeolitic component referring to the sum of the weights of the first zeolitic components and of the matrix lies between 10 and 70% by weight.
In another design of the invention, the composition consists of a mixture of particles of zeolitic components which includes
particles of the first component in a matrix,
particles of the second component, and
particles of ZSM-5 zeolite in a matrix.
This mixture of particles of zeolitic components preferably consists of a maximum of 80% by weight of particles corresponding to the first component in the matrix and ZSM-5 zeolite in a ratio by weight of ZSM-5 zeolite/first component≦10, and at least 20% of the second component.
The composition can also consist of at least one binder selected from among silica, silica-alumina, alumina, P
2
O
5
and combinations of them, and optionally, a conventional catalytic cracking additive as well. In this case, the binder can be present from 5 to 20% by weight referring to the total weight of the matrix, and the conventional additive can be present from between 0 and 60% by weight referring to the total of the composition.
In accordance with the invention, the zeolitic components contain Si and they can also contain at least one T element chosen from among the group made up of Fe, Ga, Ti and B, and optionally also a maximum of 8% by weight of phosphorus.
The second component is preferably a faujasite zeolite selected from among ultra-stable type Y zeolites, exchanged faujasite zeolites selected from among ultra-stable type zeolites partially exchanged with rare earths (REUSY), ultra-stable type zeolites partially exchanged with rare earths and calcined (CREY).
The particle size of the composition can lie between 1 and 1000 micrometres or between 100 and 200 micrometres.
Moreover, the invention also refers to the use of compositions with the characteristics described above as a catalytic material in fluid catalytic cracking processes.
The invention furthermore refers to the use of a zeolitic material containing aluminium in its structure and selected from among ITQ-7 zeolites, intergrowths of ITQ-7 zeolites, ITQ-7 zeolites exchanged with rare earths, intergrowths of ITQ-7 zeolites exchanged with rare earths, and combinations of them, as catalytic materials in hydrocarbon catalytic cracking processes.
In this case too, the zeolitic material can be contained in particles embedding at least the zeolitic material in a matrix. In this case, the zeolitic material can consist of 10 to 70% by weight along with a matrix stabilised with phosphorus, and the matrix can also include particles of at least one binder selected from
Canós Avelino Corma
Diaz Caba{overscore (n)}as María
Martinez Triguero Joaquín
Consejo Superior de Investigaciones Cientificas
Dunn Tom
Ildebrando Christina
Klauber & Jackson
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