U.S. patent application number 11/597441 was filed with the patent office on 2007-10-04 for process to produce a gas oil by catlaytic cracking of a fisher-tropsch product.
Invention is credited to Jan Lodewijk Maria Dierickx.
Application Number | 20070227946 11/597441 |
Document ID | / |
Family ID | 38557244 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070227946 |
Kind Code |
A1 |
Dierickx; Jan Lodewijk
Maria |
October 4, 2007 |
Process to Produce a Gas Oil by Catlaytic Cracking of a
Fisher-Tropsch Product
Abstract
Process to prepare a gas oil, by (a) isolating from a
Fischer-Tropsch synthesis product a first gas oil fraction and a
fraction boiling above the gas oil fraction, (b) contacting the
heavier fraction with a catalyst system comprising a catalyst,
which catalyst comprises an acidic matrix and a large pore
molecular sieve in a riser reactor at a temperature of between 450
and 650.degree. C. at a contact time of between 1 and 10 seconds
and at a catalyst to oil ratio of between 2 and 20 kg/kg, (c)
isolating from the product of step (b) a second gas oil fraction;
(d) combining the first gas oil fraction with the second gas
oil.
Inventors: |
Dierickx; Jan Lodewijk Maria;
(Amsterdam, NL) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
38557244 |
Appl. No.: |
11/597441 |
Filed: |
May 25, 2005 |
PCT Filed: |
May 25, 2005 |
PCT NO: |
PCT/EP05/52391 |
371 Date: |
November 22, 2006 |
Current U.S.
Class: |
208/113 |
Current CPC
Class: |
C10G 2300/1022 20130101;
C10G 11/18 20130101; C10G 2/332 20130101; C10G 2300/1059 20130101;
C10G 11/00 20130101; C10G 11/05 20130101; C10G 2300/4006 20130101;
C10G 2400/06 20130101 |
Class at
Publication: |
208/113 |
International
Class: |
C10G 2/00 20060101
C10G002/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2004 |
EP |
PCT EP04 050931 |
Nov 30, 2004 |
EP |
04106189.6 |
Claims
1. A process to prepare a gas oil, by (a) isolating from a
Fischer-Tropsch synthesis product a first gas oil fraction and a
heavier fraction boiling above the gas oil fraction; (b) contacting
the heavier fraction with a catalyst system comprising a catalyst,
which catalyst comprises an acidic matrix and a large pore
molecular sieve in a riser reactor at a temperature of between 450
and 650.degree. C. at a contact time of between 1 and 10 seconds
and at a catalyst to oil ratio of between 2 and 20 kg/kg; (c)
isolating from the product of step (b) a second gas oil fraction;
and (d) combining the first gas oil fraction with the second gas
oil fraction.
2. The process according to claim 1, wherein the heavier fraction
used in step (b) has a weight ratio of compounds having at least 60
or more carbon atoms, and compounds having at least 30 carbon
atoms, of at least 0.2, and wherein at least 30 wt % of the
compounds have at least 30 carbon atoms.
3. The process according to claim 2, wherein at least 50 wt % of
the compounds in the heavier fraction used in step (b) have at
least 30 carbon atoms.
4. The process according to claim 3, wherein the weight ratio of
compounds having at least 60 or more carbon atoms, and compounds
having at least 30 carbon atoms, in the Fischer-Tropsch product is
at least 0.4, in the heavier fraction used in step (b).
5. The process according to claim 1, wherein the temperature in
step (b) is below 600.degree. C.
6. The process according to claim 1, wherein the acidic matrix is
alumina.
7. The process according to claim 1, wherein the large pore
molecular sieve is of the Faujasite type.
8. The process according to claim 1, wherein the catalyst system in
step (b) also comprises zeolite beta, Erionite, Ferrierite, ZSM-5,
ZSM-11, ZSM-12, ZSM-22, ZSM-23, or ZSM-57.
9. The process according to claim 8, wherein iso and normal
pentenes and/or iso and normal hexenes produced in step (b) are
subjected to an oligomerisation step to prepare compounds boiling
in the gas oil range and wherein said compounds are combined with
the gas oil product as obtained in step (d).
10. The process according to claim 1, wherein the Fischer-Tropsch
synthesis product used as feed in step (a) is obtained by means of
a cobalt-catalyzed Fischer-Tropsch synthesis process.
11. The process according to claim 10, wherein the cobalt catalyst
is obtained by (aa) mixing (1) titania or a titania precursor, (2)
a liquid, and (3) a cobalt compound, which is at least partially
insoluble in the amount of liquid used, to form a mixture; (bb)
shaping and drying of the mixture thus obtained; and (cc)
calcination of the composition thus obtained.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a process to prepare a gas oil, in
combination with a gasoline, by catalytic cracking of a
Fischer-Tropsch product.
BACKGROUND OF THE INVENTION
[0002] It is known that paraffinic products boiling in the gas oil
range can be prepared from a Fischer-Tropsch derived synthesis
product. However, Preparing a gasoline having an acceptable octane
number, and a paraffinic gas oil, from a Fischer-Tropsch product,
using a single conversion process, is not straightforward. This
because the Fischer-Tropsch product as such consists for a large
portion of normal paraffins which have a low octane value or
contribution. Various publications are known which describe
catalytic cracking as a process to prepare a gasoline having an
acceptable octane value from a Fischer-Tropsch product. For example
U.S. Pat. No. 4,684,756 discloses a process to prepare a gasoline
fraction directly by catalytic cracking of a Fischer-Tropsch wax as
obtained in an iron catalysed Fischer-Tropsch process. The gasoline
yield is 57.2 wt %.
[0003] A disadvantage of some of the above processes involving
catalytic cracking is that the cetane number of the gas oil
fraction, which is produced in combination with the gasoline, is
too low, and the gas oil yield is low.
[0004] The object of the present invention is to prepare a high
quality paraffinic gas oil in a catalytic cracking process of a
Fischer-Tropsch product which process has as the main product a
gasoline.
SUMMARY OF THE INVENTION
[0005] Process to prepare a gas oil, by [0006] (a) isolating from a
Fischer-Tropsch synthesis product a first gas oil fraction and a
fraction boiling above the gas oil fraction, [0007] (b) contacting
the heavier fraction with a catalyst system comprising a catalyst,
which catalyst comprises an acidic matrix and a large pore
molecular sieve in a riser reactor at a temperature of between 450
and 650.degree. C. at a contact time of between 1 and 10 seconds
and at a catalyst to oil ratio of between 2 and 20 kg/kg, [0008]
(c) isolating from the product of step (b) a second gas oil
fraction; [0009] (d) combining the first gas oil fraction with the
second gas oil.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Applicants found that the first gas oil fraction, obtained
in step (a), will improve the cetane number of the second gas oil
obtained by catalytically cracking a Fischer-Tropsch synthesis
product. In a preferred embodiment, a relatively heavy
Fischer-Tropsch product is used as feed to the catalytic cracking
step (b). The enrichment of the catalytically cracked gas oil
fraction with paraffins, as obtained in step (a), increases the
cetane number to the level that makes the gas oil suitable as a
diesel fuel blend component. Another advantage is that use can be
made of well-known processes known for fluid catalytic cracking
(FCC), step (b).
[0011] The Fischer-Tropsch synthesis product may in principle be
any reaction product as obtained when performing the well know
Fischer-Tropsch synthesis reaction. Preferably use is made of a
relatively heavy Fischer-Tropsch product in step (b). This heavy
feed preferably has at least 30 wt %, preferably at least 50 wt %,
and more preferably at least 55 wt % of compounds having at least
30 carbon atoms. Furthermore the weight ratio of compounds having
at least 60 or more carbon atoms and compounds having at least 30
carbon atoms of the Fischer-Tropsch product is at least 0.2,
preferably at least 0.4 and more preferably at least 0.55.
Preferably the Fischer-Tropsch product comprises a C.sub.20+
fraction having an ASF-alpha value (Anderson-Schulz-Flory chain
growth factor) of at least 0.925, preferably at least 0.935, more
preferably at least 0.945, even more preferably at least 0.955.
[0012] The initial boiling point of the Fischer-Tropsch product
used in step (b) may suitably range from below 200 up to
450.degree. C. Preferably the initial boiling point is between 300
and 450.degree. C. in case all compounds having a boiling point in
the gas oil range are separated from the Fischer-Tropsch synthesis
product before the Fischer-Tropsch synthesis product is used in
step (b). Applicants found that a high yield to gas oil can be
achieved starting from such a Fischer-Tropsch product, thus
excluding the Fischer-Tropsch fractions boiling in the gas oil
range. The relatively heavy Fischer-Tropsch synthesis product can
be obtained by any process, which yields a relatively heavy
Fischer-Tropsch product. Not all Fischer-Tropsch processes yield
such a heavy product. Preferred processes are the cobalt catalysed
Fischer-Tropsch processes. An example of a suitable Fischer-Tropsch
process is described in WO-A-9934917 and in AU-A-698391. These
processes may yield a Fischer-Tropsch product as described
above.
[0013] A preferred catalyst to be used to obtain the relatively
heavy Fischer-Tropsch product is suitably a cobalt-containing
catalyst as obtainable by (aa) mixing (1) titania or a titania
precursor, (2) a liquid, and (3) a cobalt compound, which is at
least partially insoluble in the amount of liquid used, to form a
mixture; (bb) shaping and drying of the mixture thus obtained; and
(cc) calcination of the composition thus obtained.
[0014] Preferably at least 50 weight percent of the cobalt compound
is insoluble in the amount of liquid used, more preferably at least
70 weight percent, and even more preferably at least 80 weight
percent, and most preferably at least 90 weight percent. Preferably
the cobalt compound is metallic cobalt powder, cobalt hydroxide or
an cobalt oxide, more preferably Co(OH).sub.2 or Co.sub.3O.sub.4.
Preferably the cobalt compound is used in an amount of up to 60
weight percent of the amount of refractory oxide, more preferably
between 10 and 40 wt percent. Preferably the catalyst comprises at
least one promoter metal, preferably manganese, vanadium, rhenium,
ruthenium, zirconium, titanium or chromium, most preferably
manganese. The promoter metal(s) is preferably used in such an
amount that the atomic ratio of cobalt and promoter metal is at
least 4, more preferably at least 5. Suitably at least one promoter
metal compound is present in step (aa). Suitably the cobalt
compound is obtained by precipitation, optionally followed by
calcination. Preferably the cobalt compound and at least one of the
compounds of promoter metal are obtained by co-precipitation, more
preferably by co-precipitation at constant pH. Preferably the
cobalt compound is precipitated in the presence of at least a part
of the titania or the titania precursor, preferably in the presence
of all titania or titania precursor. Preferably the mixing in step
(aa) is performed by kneading or mulling. The thus obtained mixture
is subsequently shaped by pelletising, extrusion, granulating or
crushing, preferably by extrusion. Preferably the mixture obtained
has a solids content in the range of from 30 to 90% by weight,
preferably of from 50 to 80% by weight. Preferably the mixture
formed in step (aa) is a slurry and the slurry thus-obtained is
shaped and dried by spray-drying. Preferably the slurry obtained
has a solids content in the range of from 1 to 30% by weight, more
preferably of from 5 to 20% by weight. Preferably the calcination
is carried out at a temperature between 400 and 750.degree. C.,
more preferably between 500 and 650.degree. C. Further details are
described in WO-A-9934917.
[0015] The Fischer-Tropsch process is typically carried out at a
temperature in the range from 125 to 350.degree. C., preferably 175
to 275.degree. C. The pressure is typically in the range from 5 to
150 bar abs., preferably from 5 to 80 bar abs., in particular from
5 to 70 bar abs. Hydrogen (H.sub.2) and carbon monoxide (synthesis
gas) is typically fed to the process at a molar ratio in the range
from 0.5 to 2.5. The gas hourly space velocity (GHSV) of the
synthesis gas in the process of the present invention may vary
within wide ranges and is typically in the range from 400 to 10000
Nl/l/h, for example from 400 to 4000 Nl/l/h. The term GHSV is well
known in the art, and relates to the volume of synthesis gas in Nl,
i.e. litres at STP conditions (0.degree. C. and 1 bar abs), which
is contacted in one hour with one litre of catalyst particles, i.e.
excluding interparticular void spaces. In the case of a fixed
catalyst bed, the GHSV may also be expressed as per litre of
catalyst bed, i.e. including interparticular void space. The
Fischer-Tropsch synthesis can be performed in a slurry reactor or
preferably in a fixed bed. Further details are described in
WO-A-9934917.
[0016] Synthesis gas may be obtained by well known processes like
partial oxidation and steam reforming and combinations of these
processes starting with a (hydro) carbon feedstock. Examples of
possible feedstocks are natural gas, associated gas, refinery
off-gas, residual fractions of crude oil, coal, pet coke and
biomass, for example wood. Partial oxidation may be catalysed or
non-catalyzed. Steam reforming may be for example conventional
steam reforming, autothermal (ATR) reforming and convective steam
reforming. Examples of suitable partial oxidation processes are the
Shell Gasification Process and the Shell Coal Gasification
Process.
[0017] The Fischer-Tropsch product will contain no or very little
sulphur and nitrogen containing compounds. This is typical for a
product derived from a Fischer-Tropsch reaction, which uses
synthesis gas containing almost no impurities. Sulphur and nitrogen
levels will generally be below the detection limits, which are
currently 5 ppm for sulphur and 1 ppm for nitrogen. The
Fischer-Tropsch product can advantageously be directly used in step
(a) without having to hydrotreat the feed to remove olefins and/or
oxygenates.
[0018] The catalyst system used in step (b) will at least comprise
of a catalyst comprising of a matrix and a large pore molecular
sieve. Examples of suitable large pore molecular sieves are of the
faujasite (FAU) type as for example Zeolite Y, Ultra Stable Zeolite
Y and Zeolite X. The matrix is preferably an acidic matrix. The
acidic matrix will suitably comprise amorphous alumina and
preferably more than 10 wt % of the catalyst is amorphous alumina.
The matrix may further comprise, for example, aluminium phosphate,
clay and silica and mixtures thereof. Amorphous alumina may also be
used as a binder to provide the matrix with enough binding function
to properly bind the molecular sieve. Examples of suitable
catalysts are commercially available catalysts used in fluid
catalytic cracking processes which catalysts comprise a Zeolite Y
as the molecular sieve and at least alumina in the matrix.
[0019] The temperature at which feed and catalyst contact is
between 450 and 650.degree. C. More preferably the temperature is
above 475.degree. C. and even more preferably above 500.degree. C.
Good gasoline yields are seen at temperatures above 600.degree. C.
However higher temperatures than 600.degree. C. will give rise to
thermal cracking reactions and the formation of non-desirable
gaseous products like for example methane and ethane. For this
reason, the temperature is more preferably below 600.degree. C. The
process may be performed in various types of reactors. Because the
coke make is relatively small, as compared to an FCC process
operating on a petroleum-derived feed, it is possible to conduct
the process in a fixed bed reactor. In order to be able to
regenerate the catalyst more simply, preference is nevertheless
given to either a fluidised bed reactor or a riser reactor. If the
process is performed in a riser reactor, the preferred contact time
is between 1 and 10 seconds and more preferred between 2 and 7
seconds. The catalyst to oil ratio is preferably between 2 and 20
kg/kg. It has been found that good results may be obtained at low
catalyst to oil ratios of below 15 and even below 10 kg/kg.
[0020] This is advantageous because this means a higher
productivity per catalyst resulting in, e.g. smaller equipment,
less catalyst inventory, less energy requirement and/or higher
productivity.
[0021] The catalyst system may advantageously also comprise of a
medium pore size molecular sieve such to also obtain a high yield
of propylene and other lower olefins next to the gasoline fraction.
It has also been found that the yield to gas oil increases when
such medium pore molecular sieves are present. Preferred medium
pore size molecular sieves are zeolite beta, Erionite, Ferrierite,
ZSM-5, ZSM-11, ZSM-12, ZSM-22, ZSM-23 or ZSM-57. The weight
fraction of medium pore crystals on the total of molecular sieves
present in this process is preferably between 2 and 20 wt %. The
medium pore molecular sieve and the large pore molecular sieve may
be combined in one catalyst particle or be present in different
catalyst particles. Preferably, the large and medium pore molecular
sieves are present in different catalyst particles for practical
reasons. For example, the operator can thus add the two catalyst
components of the catalyst system at different addition rates to
the process. This could be required because of different
deactivation rates of the two catalysts. A suitable matrix is
alumina. The molecular sieve may be dealuminated by for example
steaming or other known techniques.
[0022] It has been found that the combination of the large pore
molecular sieve, more preferably of the FAU type, in combination
with the medium pore size molecular sieve, results in a high
selectivity to the lower olefins. Applicants have found that, by
performing the process according the invention with a large pore
molecular sieve, more preferably of the FAU type, in combination
with the medium pore size molecular sieve, as described above, not
only lower olefin yield improves, but also the yield to the iso and
normal pentenes and hexenes increases. In such an embodiment these
pentenes and hexenes are preferably oligomerised to compounds
boiling in the gas oil range. This is preferred for at least two
reasons, namely that the ultimate yield to gas oil increases and
also because low octane contributing compounds are removed from the
gasoline. Oligomerisation is a well known process and is for
example exemplified in US-A-20020111521.
[0023] In step (c) a second gas oil fraction is isolated from the
product of step (b) from the main gasoline product. Isolation of
said fractions is suitably performed by means of distillation. In
this invention a gasoline or gasoline fraction is a fraction
boiling for more than 90 wt % between 25 and 215.degree. C.,
preferably boiling for more than 95 wt % in said boiling range. A
gas oil or gas oil fraction is a fraction boiling for more than 90
wt % between 200 and 370.degree. C., preferably boiling for more
than 90 wt % between 215 and 350.degree. C.
[0024] The first and second gas oil fraction may separately or in a
mixture be subjected to an additional catalytic dewaxing step in
order to reduce the pour point to an acceptable level if required.
Such a treatment is not only advantageous for reducing the pour
point but will also decrease the content of any aromatic compounds
formed in step (a). The pour point is preferably below -10.degree.
C. and even more preferably below -15.degree. C. Catalytic gas oil
dewaxing may suitably be performed using a catalyst comprising a
binder, a molecular sieve and a hydrogenation metal component. The
binder may be any binder, suitably alumina, silica-alumina or
silica. The molecular sieve is preferably a zeolite or a
silica-aluminophosphate (SAPO) material. The zeolites preferably
have a pore diameter of between 0.35 and 0.8 nm. Suitable
intermediate pore size zeolites are mordenite, Zeolite Beta, ZSM-5,
ZSM-12, ZSM-22, ZSM-23, MCM-68, SSZ-32, ZSM-35 and ZSM-48.
Preferred silica-aluminophosphate (SAPO) materials are SAPO-11. The
hydrogenation component is preferably a Group VIII metal, more
preferably nickel, cobalt, platinum or palladium. Most preferably
the noble metal Group VIII metals are used. Catalytic dewaxing
conditions are known in the art and typically involve operating
temperatures in the range of from 200 to 500.degree. C., suitably
from 250 to 400.degree. C., hydrogen partial pressures in the range
of from 10 to 200 bar, preferably from 15 to 100 bar, weight hourly
space velocities (WHSV) in the range of from 0.1 to 10 kg of oil
per litre of catalyst per hour (kg/l/hr), suitably from 0.2 to 5
kg/l/hr, more suitably from 0.5 to 3 kg/l/hr and hydrogen to oil
ratios in the range of from 100 to 2,000 litres of hydrogen per
litre of oil. Examples of suitable dewaxing processes and catalysts
are described in WO-A-200029511 and EP-B-832171.
EXAMPLES A-D
[0025] A Fischer-Tropsch product having the properties as listed in
Table 1 was contacted with a hot regenerated catalyst at different
temperatures and contact times at a catalyst to oil ratio of 4
kg/kg. The catalyst was a commercial FCC catalyst comprising an
alumina matrix and Ultra Stable Zeolite Y, which had been obtained
from a commercially operating FCC unit. The Zeolite Y content was
10 wt %. The operating conditions are presented in Table 3.
TABLE-US-00001 TABLE 1 Initial boiling point 100.degree. C.
Fraction boiling between 25 and 215.degree. C. (wt %) 46.8 Fraction
boiling between 215 and 325.degree. C. (wt %) 42.2 Fraction boiling
above 325.degree. C. (wt %) 11.0
EXAMPLES 1-4
[0026] A Fischer-Tropsch product having the properties as listed in
Table 2 was contacted with a hot regenerated catalyst at different
temperatures and contact times as in Examples A-D. The
Fischer-Tropsch product was obtained according to Example VII using
the catalyst of Example III of WO-A-9934917. The operating
conditions are presented in Table 3. TABLE-US-00002 TABLE 2 Initial
boiling point 280.degree. C. Weight Fraction having 10 or less
carbon 0 atoms(%) Weight Fraction having more than 30 carbon 80
atoms(%) Weight Fraction having more than 60 carbon 50 atoms(%)
Ratio of C.sub.60+/C.sub.30+ 0.63
[0027] TABLE-US-00003 TABLE 3 Temperature Contact Time Experiment
Example (.degree. C.) (seconds) A 1 500 4.06 B 2, 5 525 0.7 C 3, 6
525 4.06 D 4, 7 625 0.7
[0028] TABLE-US-00004 TABLE 4 Middle Gasoline distillate Gasoline
normal yield (wt % on yield (wt % on and iso-pentenes total total
(wt % in gasoline Example product) (*) product) (**) fraction) A --
-- -- 1 74.00 11.06 16.92 B 52.58 35.38 2.01 2 52.90 13.27 18.85 C
68.70 13.63 13.66 3 70.29 5.91 39.75 D 53.86 26.24 24.09 4 46.12
7.43 36.32 (*) Gasoline fraction defined as the distillation cut
boiling between 25 and 215.degree. C. (**) Middle distillate
defined as the distillation cut boiling between 215 and 325.degree.
C.
[0029] From Table 4, it can be derived that the process according
to the invention will provide high yields to gasoline and middle
distillate, or gas oil. In Examples 1-4, gas oil yields are lower
than in Examples B-D, but the gas oil content in the feed to
experiments B-D is 42.2 wt % (Table 1), which is higher than the
gas oil yield in any of experiments B-D. In addition, the gasoline
fractions from experiments 1-4 contain considerable amounts of
normal and iso-pentenes, which can be oligomerised to gas oil.
[0030] Table 4 also shows that a high gasoline yield is obtained at
high contact times and relatively mild temperatures (Examples B and
2).
EXAMPLES 5-7
[0031] Examples 2-4 were repeated with the Fischer-Tropsch product
having the properties as listed in Table 5 and the conditions of
Table 3. The feed in Table 5 can be obtained from the feed in Table
2, by removing 22 wt % of the gas oil and lighter fraction of Table
1. The yields are presented in Table 6. The gas oil yields are
higher than the yields in Examples 2-4, but considerably lower than
the sum of the gas oil yields from Examples 2-4 and the 9 wt % (on
total feed) gas oil that can be recovered from the fraction of
Table 1, and blended with the gas oil fractions obtained in
Examples 2-4, according to the invention. TABLE-US-00005 TABLE 5
Initial boiling point 100.degree. C. Weight Fraction having 10 or
less carbon 14 atoms (%) Weight Fraction having more than 30 carbon
62 atoms(%) Weight Fraction having more than 60 carbon 39 atoms(%)
Ratio of C.sub.60+/C.sub.30+ 0.63
[0032] TABLE-US-00006 TABLE 6 Middle Gasoline distillate Gasoline
normal yield (wt % yield (wt % on and iso-pentenes on total total
(wt % in gasoline Example product) (*) product) (**) fraction) 5
52.85 16.57 16.25 6 70.05 7.04 35.73 7 47.25 10.18 34.40 (*)
Gasoline fraction defined as the distillation cut boiling between
25 and 215.degree. C. (**) Middle distillate defined as the
distillation cut boiling between 215 and 325.degree. C.
EXAMPLE 8
[0033] Example 6 was repeated except that part of the catalyst was
exchanged for a 25 wt % ZSM-5 containing catalyst. The content of
ZSM-5 based catalyst on the whole catalyst charge was 20 wt % (as
calculated on the total catalyst weight). The gasoline yield was
47.99 wt %, and the middle distillate yield 9.27 wt % on total
product. The content of normal and iso-pentenes was 54.61 wt % in
the gasoline fraction.
EXAMPLE 9
[0034] Example 2 was repeated except that part of the catalyst was
exchanged for a 25 wt % ZSM-5 containing catalyst. The content of
ZSM-5 based catalyst on the whole catalyst charge was 20 wt % (as
calculated on the total catalyst weight). The results are presented
in Table 7.
EXAMPLE 10
[0035] Example 3 was repeated except that part of the catalyst was
exchanged for a 25 wt % ZSM-5 containing catalyst. The content of
ZSM-5 based catalyst on the whole catalyst charge was 20 wt % (as
calculated on the total catalyst weight). The results are presented
in Table 7. TABLE-US-00007 TABLE 7 Middle Gasoline distillate
Gasoline normal yield (wt % yield (wt % on and iso-pentenes on
total total (wt % in gasoline Example product) (*) product) (**)
fraction) 2 52.90 13.27 18.85 3 70.29 5.91 39.75 9 55.88 13.39
11.47 10 45.76 8.07 67.14 (*) Gasoline fraction defined as the
distillation cut boiling between 25 and 215.degree. C. (**) Middle
distillate defined as the distillation cut boiling between 215 and
325.degree. C.
Example 8-10 show that the addition of ZSM-5 increases oil
yields.
* * * * *