Mineral oils: processes and products – Chemical conversion of hydrocarbons – Cracking
Reexamination Certificate
2000-02-23
2002-02-05
Preisch, Nadine (Department: 1764)
Mineral oils: processes and products
Chemical conversion of hydrocarbons
Cracking
C208S109000, C208S110000, C208S111050, C208S111200, C208S111300, C208S111350
Reexamination Certificate
active
06344135
ABSTRACT:
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 m
2
/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 (390° 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 h
−1
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:
100XO
2
, mY
2
O
3
, pR
2
O
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.
TABLE 1
X ray diffraction table for IM-5 zeolite, as synthesised state
d
hkl
(Å)
I/I
max
11.8 ± 0.35
s to vs (1)
11.5 ± 0.30
s to vs (1)
11.25 ± 0.30
s to vs (1)
9.95 ± 0.20
m to s
9.50 ± 0.15
m to s
7.08 ± 0.12
w to m
6.04 ± 0.10
vw to w
5.75 ± 0.10
w
5.65 ± 0.10
w
5.50 ± 0.10
vw
5.35 ± 0.10
vw
5.03 ± 0.09
vw
4.72 ± 0.08
w to m
4.55 ± 0.07
w
4.26 ± 0.07
vw
3.92 ± 0.07
s to vs (2)
3.94 ± 0.07
vs (2)
3.85 ± 0.05
vs (2)
3.78 ± 0.04
s to vs (2)
3.67 ± 0.04
m to s
3.55 ± 0.03
m to s
3.37 ± 0.02
w
3.30 ± 0.015
w
3.099 ± 0.012
w to m
2.970 ± 0.007
vw to w
2.815 ± 0.005
vw
2.720 ± 0.005
vw
(1) Peaks forming part of the same feature.
(2) Peaks forming part of the same feature.
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.
TABLE 2
X ray diffraction table for IM-5 zeolite in its hydrogen form, H-IM-5,
obtained by calcining
d
hkl
(Å)
I/I
max
11.8 ± 0.30
s to vs (1)
11.45 ± 0.25
vs (1)
11.20 ± 0.20
s to vs (1)
9.90 ± 0.15
m to s
9.50 ± 0.15
m to s
7.06 ± 0.12
w to m
6.01 ± 0.10
vw to w
5.70 ± 0.10
w
5.30 ± 0.10
vw
5.03 ± 0.09
vw
4.71 ± 0.08
w
4.25 ± 0.07
vw
3.87 ± 0.07
m to s (2)
3.81 ± 0.05
m to s (2)
3.76 ± 0.04
m to s (2)
3.67 ± 0.04
w to m
3.54 ± 0.04
m to s
3.37 ± 0.03
w
3.316 ± 0.015
w
3.103 ± 0.102
w
3.080 ± 0.010
w to m
2.950 ± 0.010
vw to w
2.880 ± 0.007
vw
2.790 ± 0.005
vw
2.590 ± 0.005
vw
(1) Peaks form part of the same feature.
(2) Peaks form part of the same feature.
These diagrams were obtained using a diffractometer and a conventional powder method utilising the K
&agr;
line of copper. From the position of the diffraction peaks represented by the anole 2&thgr;, the characteristic interplanar distances d
hkl
of the sample can be calculated using the Bragg equation. The intensity is calc
Benazzi Eric
Kasztelan Slavik
Millen, WHite, Zelano & Branigan, P.C.
Preisch Nadine
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