Source: {"pile_set_name": "USPTO Backgrounds"}

The present invention relates to a hydrocracking process comprising at least one matrix, an IM-5 zeolite, at least one hydrodehydrogenating metal preferably selected from the group formed by metals from group VIB and group VIII of the periodic table, optionally at least one promoter element selected from the group formed by phosphorous, boron and silicon, optionally at least one group VIIA element, optionally at least one group VIIB element and optionally at least one group VB element. The invention also relates to a catalyst based on IM-5 zeolite, containing at least one hydrodehydrogenating metal selected from the group formed by group VI and group VIII metals, and containing at least one promoter element selected from the group formed by boron and silicon.
Hydrocracking heavy petroleum feeds is a very important refining process which produces lighter fractions such as gasoline, jet fuel and light gas oil from surplus heavy feeds of low intrinsic value, which lighter fractions are needed by the refiner to enable production to be matched to demand. Some hydrocracking processes can also produce a highly purified residue which can constitute an excellent base for oils. The advantage of catalytic hydrocracking over catalytic cracking is that it can provide very good quality middle distillates, jet fuels and gas oils. The gasoline produced has a much lower octane number than that resulting from catalytic cracking.
All catalysts used for hydrocracking are bifunctional, combining an acid function and a hydrogenating function. The acid function is supplied by large surface area supports (150 to 800 m2/g in general) with a superficial acidity, such as halogenated aluminas (in particular fluorinated or chlorinated), combinations of boron and aluminum oxides, amorphous silica-aluminas and zeolites. The hydrogenating function is supplied either by one or more metals from group VIII of the periodic table, or by a combination of at least one metal from group VIB of the periodic table, and at least one group VIII metal.
The equilibrium between the two, acid and hydrogenating, functions is the fundamental parameter which governs the activity and selectivity of the catalyst. A weak acid function and a strong hydrogenating function produces low activity catalysts which generally operate at a high temperature (390xc2x0 C. or above), and at a low supply space velocity (HSV, expressed as the volume of feed to be treated per unit volume of catalyst per hour, and is generally 2 hxe2x88x921 or less), but have very good selectivity for middle distillates. In contrast, a strong acid function and a weak hydrogenating function produces very active catalysts but selectivities for middle distillates are poorer. The search for suitable catalysts thus revolves around the proper selection of each of the functions to adjust the activity/selectivity balance of the catalyst.
Thus one of the great interests of hydrocracking is to have a high degree of flexibility at various levels: flexibility as regards the catalysts used, which provides flexibility in the feeds to be treated and in the products obtained. One parameter which is easily mastered is the acidity of the catalyst support.
The vast majority of conventional hydrocracking catalysts are constituted by low aridity supports such as amorphous silica-aluminas. These systems are more particularly used to produce very high quality middle distillates and again, when their acidity is very low, base oils.
Amorphous silica-aluminas are low acidity supports. Many of the catalysts in the hydrocracking industry are based on silica-alumina associated either with a group VIII metal or, as is preferable when the heteroatomic poison content in the feed to be treated exceeds 0.5% by weight, a combination of sulphides of group VIB and VIII metals. These systems have very good selectivity for middle distillates, and good quality products are formed. The least acid of such catalysts can also produce lubricating bases. The disadvantage of all of such catalytic systems based on an amorphous support is, as has been stated, their low activity.
Catalysts comprising a Y zeolite with structure type FAU, or beta type catalysts have a catalytic activity which is higher than that of amorphous silica-aluminas, but have hither selectivities for light products.
The research carried out by the Applicant on numerous zeolites and microporous crystalline solids have led to the surprising discovery that a catalyst based on an IM-5 zeolite can achieve a catalytic activity and kerosine and gasoline selectivities which are substantially improved over catalysts containing a prior art zeolite.
More precisely, the invention provides a process for hydrocracking hydrocarbon-containing feeds in which the feed to be treated is brought into contact with a catalyst comprising at least one amorphous or low crystallinity matrix of an oxide type, at least one IM-5 zeolite and at least one hydrodehydrogenating element.
The IM-5 zeolite used in the present invention has been described in French patent FR-A-2 754 809. The invention also encompasses any zeolite of the same structure type as that of IM-5 zeolite.
The zeolitic structure, termed IM-5, has a chemical composition with the following formula, expressed in terms of the mole ratios of the oxides for the anhydrous state:
100XO2, mY2O3, pR2/nO
where
m is 10 or less;
p is in the range 0 (excluded) to 20;
R represents one or more cations with valency n;
X represents silicon and/or germanium, preferably silicon;
Y is selected from the group formed by the following elements: aluminum, iron, gallium, boron, and titanium, Y preferably being aluminum; and is characterized by an X ray diffraction diagram, in its as synthesised state, which comprises the peaks shown in Table 1.
The IM-5 zeolite in its hydrogen form, designated H-IM-5, is obtained by calcining step(s) and/or ion exchange step(s) as will be explained below. The H-IM-5 zeolite has an X ray diffraction diagram which comprises the results shown in Table 2.
These diagrams were obtained using a diffractometer and a conventional powder method utilising the Kxcex1line of copper. From the position of the diffraction peaks represented by the anole 2xcex8, the characteristic interplanar distances dhkl of the sample can be calculated using the Bragg equation. The intensity is calculated on the basis of a relative intensity scale attributing a value of 100 to the line representing the strongest peak on the X ray diffraction diagram, and then:
very weak (vw) means less than 10;
weak (w) means less than 20;
medium (m) means in the range 20 to 40;
strong (s) means in the range 40 to 60;
very strong (vs) means more than 60.
The IM-5 zeolite can thus be used in its xe2x80x9cas synthesisedxe2x80x9d form and in forms obtained by dehydration and/or calcining and/or ion exchange. The expression xe2x80x9cin its as synthesised formxe2x80x9d means the product obtained by synthesis and washing with or without drying or dehydration. In its xe2x80x9cas synthesisedxe2x80x9d form, the IM-5 zeolite can comprise a cation of metal M, which is an alkali, in particular sodium, and/or ammonium, and it can comprise organic nitrogen-containing cations such as those described below or their decomposition products, or precursors thereof. These organic nitrogen-containing cations are designated here by the letter Q, which also includes decomposition products and precursors of said nitrogen-containing organic cations.
The calcined forms of the IM-5 zeolite contain no organic nitrogen-containing compounds, or a lower quantity than in the xe2x80x9cas synthesised formxe2x80x9d, provided that the majority of the organic substance has been eliminated, generally by a heat treatment consisting of burning the organic substance in the presence of air, the hydrogen ion (H+) thus forming the other cation.
Of the TM-5 zeolite form5 which can be obtained by ion exchange, the ammonium form (NH4+) is important as it can readily be converted into the hydrogen form by calcininig. The hydrogen form and forms containing metals introduced by ion exchange will be described below.
In some cases, the fact that the zeolite of the invention is subjected to the action of an acid can give rise to partial or complete elimination of a base element such as aluminum, as well as generation of the hydrogen form. This may constitute a means of modifying the composition of the substance after it has been synthesised.
IM-5 zeolite in its hydrogen form (acid form), termed H-IM-5, is produced by calcining and ion exchange as will be described below.
The IM-5 zeolite can also be used at least partially in its H+ form (as defined above) or in its NH4+ form or in its metallic form, said metal being selected from the group formed by groups IA, IB, IIA, IIB, IIIA, IIIB (including the rare earths), VIII, Sn, Pb and Si, preferably at least partially in its H+ form or at least partially in its metal form.
Preferably, the IM-5 zeolite is at least partially in its acid form (and preferably completely in its H form) or partially exchanged with metal cations, for example alkaline-earth metal cations.
The IM-5 zeolites which form part of the composition of the invention are used with the silicon and aluminum contents obtained on synthesis.
It is also possible to use dealuminated IM-5 zeolite, which is described in French patent FR-A-2