Note: Descriptions are shown in the official language in which they were submitted.
1~17Q58
The invention relates to a process for the preparation of one
or more atmospheric hydrocarbon oil distillates from an atmospheric hydro-
carbon oil residue.
In the atmospheric distillation of crude mineral oil, as applied
on a large scale in refineries for the preparation of atmospheric
distillates, a residual oil is obtained as a by-product. In some cases
this residual oil is suitable for use as the starting material in the
preparation of lubricating oil, but generally the residual oil, which
as a rule contains considerable quantities of sulphur, metals and
asphaltenes, is only suitable for use as fuel oil.
In view of the increasing demand for atmospheric distillates,
several processes were investigated in the past which were aimed at
converting the residual oils into atmospheric distillates. Examples
of such processes are catalytic cracking and hydrocracking. The use
of the residual oils as such as the feed for these processes has considerable
disadvantages which preclude their application on a commercial scale.
Thus, a major drawback of catalytic cracking of the residual oils
is that because of the very high coke and gas production only a low
yield of the desired atmospheric distillates is obtained. Hvdrocracking
of the residual oils involves a very rapid catalyst deactivation and/or
a very high gas production and/or a very high hydrogen consumption.
In view of the above and considering the f`act that in the atmospheric
distillation of crude mineral oil about half of the crude oil is left
behind as distillation residue, it will be clear that there is an urgent
need for a process which offers the possibility of converting atmospheric
hydrocarbon oil residues in an economically justifiable way into atmospheric
hydrocarbon oil distillates such as gasolines.
Since catalytic cracking and hydrocracking have proved in practice
to be excellent processes for the conversion of heavy hydrocarbon
oil distillates such as vacuum gas oils into light distillates such
as gasolines, the Applicant has carried out an investigation fo find
out to what extent these processes can be employed in the conversion
of the above-mentioned atmospheric residues. It has been found that
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by a proper combination of catalytic cracking and/or hydrocrack-
ing as the main operation(s) with a catalytic hydrotreatment and
a deasphalting as supplementary operations, a process can be
realized that is highly suitable for this purpose. The present
patent application relates to such a process.
Thus this invention provides a process or the prepara-
tion of one or more hydrocarbon oil distillates by means of cat-
alytic cracking or hydrocracking as the main operation in com-
bination with catalytic hydrotreatment and deasphalting as
supplementary operations starting from a hydrocarbon oil residue
obtained by atmospheric distillation, which process comprises
the steps of
(a) subjecting the said atmospheric distillation residue to a
catalytic hydrotreatment,
(b) separating a hydrotreated product obtained in step (a) into
one or more atmospheric distillates, a vacuum distillate and
a vacuum residue by means of distillation,
(c) separating the vacuum residue obtained in step (b) into a
deasphalted oil and asphalt by means of deasphalting,
(d) converting the vacuum distillate obtained in step (b) and
the deasphalted oil obtained in step (c) by means of cata-
lytic cracking or hydrocracking into one or more atmospheric
distillates, and
(e) subjecting at least 50% by weight of the asphalt obtained in
step (c) to a catalytic hydrotreatment, said catalytic hydro-
treatment being carried out under such conditions that more
than 50~ by weight of the asphalt present in the feed for the
catalytic hydrotreatment is converted into material that is
not precipitated in a deasphalting step carried out under
the same conditions as the deasphalting of the vacuum residue.
The process according to the invention comprises
catalytic cracking and/or hydrocracking of a vacuum distillate
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,.
11~7~58
and a deasphalted oil as the main operation(s). In these opera-
tions a considerable proportion of the feed concerned is con-
verted into the said atmospheric distillates. One or more
atmospheric distillates are separated as end products from the
cracked product by distillation. To increase the yield of
atmospheric distillates it is preferred to recycle at least part
of the atmospheric residue obtained in the distillation of the
cracked product to the catalytic cracker or hydrocracker. If
the process according to the invention comprises catalytic crack-
ing as one of the main operations and, in addition, at least partof the aforementioned atmospheric residue is recycled to the
catalytic cracking unit and/or a deasphalted oil is used as the
feed or as a feed component for the catalytic cracking unit,
these liquids are preferably given a light catalytic hydrotreat-
ment before they are subjected to catalytic cracking. In
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the catalytic cracking process, which is preferably carried out in
the presence of a zeolitic catalyst, coke is depcsited on the catalyst.
~his coke is removed from the catalyst by burning-off during a catalyst
regeneration step that is combined with the catalytic cracking, whereby
a waste gas is obtained which contains carbon monoxide and carbon
dioxide. Catalytic cracking is preferably carried out at an average
temperature of from 400 to 550C and in particular from 450 to 525C,
a pressure of from 1 to 10 bar and in particular from 1.5 to 7.5 bar,
a space velocity of from 0.25 to 4 kg.kg 1.h and in particular from
0.5 to 2.5 kg.kg .h and a rate of catalyst replenishment of from
0.1 to 5 and in particular from 0.2 to 2 tonnes of catalyst per 1000
tonnes of feed.
~he process according to the invention may comprise hydrocracking
as one of the main operations. Hydrocracking is effected by contacting
the feed at elevated temperature and pressure and in the presence of
hydrogen with a suitable hydrocracking catalyst. Hydrocracking is preferably
carried out as a two-stage process, in which the hydrocracking proper,
which is effected in the second stage, is preceded by a catalytic hydro-
treatment which serves mainly to reduce the nitrogen and polyaromatics
contents of the feed to be hydrocracked. Catalysts suitable for use
in the single stage hydrocracking process as well as in the second
stage of the two-stage hydrocracking process are moderately and strongly
acidic catalysts comprising one or more metals having hydrogenation
activity on a carrier. Catalysts suitable for use in the first stage
f the two-stage hydrocracking process are weakly and moderately acidic
catalysts comprising one or more metals having hydrogenation activity
on a carrier. Hydrocracking is preferably carried out at an average
temperature of from 250 to 450C and in particular from 300 to 425C,
a hydrogen partial pressure of from 25 to 300 bar and in particular
from 50 to 150 bar, a space velocity of from 0.1 to 10 kg.l .h
and in particular from 0.25 to 2 kg.l .h 1 and a hydrogen-to-feed
ratio of from 200 to 3000 Nl.kg and in particular from 500 to 2000
Nl.kg . If the hydrocracking is carried out according to the two-stage
process it is preferred to use the whole reaction product from the
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first stage (without ammonia, hydrogen sulphide or other volatile components
being separated from it) as the feed for the second stage.
The process according to the invention comprises a supplementary
operation in which deasphalting is applied to the vacuum residue of
the hydrotreated product. The deasphalting is preferably carried out
at elevated temperature and pressure and in the presence of an excess
of a lower hydrocarbon such as propane, butane or pentane.
The process according to the invention comprises a further supple-
mentary operation in which a catalytic hydrotreatment is applied to
a mixture of an atmospheric residue and asphalt. This catalytic hydro-
treatment has to be carried out under such conditions that more than
50 %w of the asphalt present in the feed for the catalytic hydrotreatment
is converted into material which does not precipitate in a deasphalting
step effected under the same conditions as the deasphalting of the
vacuum residue. This catalytic hydrotreatment is preferably carried
out as a two-stage process, in which the conversion proper of asphalt,
which conversion is effected in the second stage, is preceded by a
catalytic hydrotreatment intended mainly to reduce the metal content
of the feed to be converted. Catalysts suitable for use in the one-stage
catalytic hydrotreatment as well as in the second stage of the two-stage
catalytic hydrotreatment comprise one or more metals having hydrogenation
activity on a carrier, which carrier consists of more than 40 ~Ow alumina.
Catalysts suitable for use in the first stage of the two-stage catalytic
hydrotreatment consist of more than 80 ~Ow silica. The catalytic hydro-
treatment is preferably carried out at an average temperature of from
; 375 to 475C and in particular from 390 to 450C, a hydrogen partial
pressure of from 25 to 300 bar and in particular from 50 to 200 bar,
a space velocity of from 0.1 to 3.0 kg.l .h and in particular from
0.2 to 2.0 kg.l .h and a hydrogen-to-feed ratio of from 250 to 2500
Nl.kg 1 and in particular from 500 to 2000 Nl.kg . If the catalytic
hydrotreatment is carried out in two stages, the first stage is preferably
effected in the presence of a quantity of H2S corresponding to an H2S
content of the gas at the reactor inlet of more than 10 ~v and the
second stage in the presence of a quantity of X2S corresponding to
an H2S content of the gas at the reactor inlet of less than 5 ~Ov.
1117058
As stated hereinbefore, the catalytic hydrotreatment according
to the invention has to be carried out under such conditions that
more than 50 ~w of the asphalt present in the feed for the catalytic
hydrotreatment is converted into products which do not precipitate
in a deasphalting step effected under the same conditions as the deasphalting
of the vacuum residue, Among these products are atmospheric distillates
which are suitable as end products.
In the process according to the invention two streams are obtained
which have to be subjected to catalytic cracking or hydrocracking,
viz, a deasphalted oil and a vacuum distillate. For the conversion
of the two streams preference is given to the same treatment and to
treatment in one unit.
The process according to the invention is suitable both for the
preparation of exclusively one or more light distillates as the end
products and for the preparation of one or more light distillates together
with one or more middle distillates as the end products. If the aim
is to prepare exclusively one or more light distillates as the end
products, a middle distillate to be separated from the cracked product
and having an initial boiling point above the final boiling point
of the heaviest light distillate desired is also eligible for repeated
cracking, In that case, besides the vacuum distillate of the hydro-
treated product, a middle distillate to be separated from the hydro-
treated product and having an initial boiling point above the final
boiling point of the heaviest light distillate desired is also eligible
for use as feed component for the catalytic cracking or hydrocracking
to be carried out as the main operation~
A process scheme for the conversion of atmospheric hydrocarbon
oil residues into light and medium hydrocarbon oil distillates will
be described hereinafter in more detail by reference to the a~pended
figure.
Process scheme (see figure)
The process is carried out in an apparatus comprising successively
a catalytic hydrotreating section (1), the first atmospheric distillation
section (2), a vacuum distillation section (3), a deasphalting section
i~70~8
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(4), a catalytic cracking section (5), and the second atmospheric
distillation section (6). A hydrocarbon oil residue (7) obtained by
atmospheric distillation is mixed with an asphalt (8) and the mixture,
together with a hydrogen stream (9), is subjected to a catalytic hydro-
treatment. After separation of a gas stream (10), substantially consisting
of C4 hydrocarbons and H2S, from the hydrotreated product, the liquid
reaction product ( 11 ) is separated by atmospheric distillation into
a gasoline fraction (12), a middle distillate fraction (13) and a
residue (14). The residue (14) is separated by vacuum distillation
into a vacuum distillate (15) and a vacuum residue (16). The vacuum
residue (16) is separated by deasphalting into a deasphalted oil (17)
and an asphalt (18). The asphalt (18) is separated into t~ro portions
(8) and (19) having the same composition. The vacuum distillate (15)
is mixed with the deasphalted oil (17) and the mixture is catalytically
cracked, In the regeneration of the catalyst in the catalytic cracking
unit a waste gas (20) is obtained which contains carbon monoxide and
carbon dioxide. The catalytically cracked product (21) is separated
by atmospheric distillation into a C4 fraction (22), a gasoline fraction
(23), a middle distillate fraction (24) and a residue (25) being a
mixture of heavy cycle oil and slurry oil.
The present patent application also comprises an apparatus for
carrying out the process according to the invention as schematically
shown in the appended figure.
The process according to the invention was applied to an atmospheric
distillation residue of a crude oil from the Middle East. The atmospheric
distillation residue had an initial boi'ing point of 370C. By vacuum
distillation of 100 pbw of the atmospheric residue, 44 pbw of a 520C
vacuum residue could be separated from it; by deasphalting these 44 pbw
vacuurn residue at 145C and 41 bar with butane as the solvent and
a solvent-to-oil weight ratio of 4:1, 21 pbw of C4 asphalt could be
obtained from it. The process was carried out according to the appended
process scheme. The following conditions were used in the various
sections.
The catalytic cracking was effected in the presence of a zeolitic
1~17(~58
catalyst at a temperature of 490C, a pressure of 2.2 bar and a space
velocity of 2 kg.kg .h
The catalytic hydrotreatment was effected in two stages in the
presence of an Ni/V/SiO2 catalyst comprising 0,5 pbw nickel and 2 pbw
vanadium per 100 pbw silica in the first stage, and an Ni/Mo/Al203
catalyst comprising 4 pbw nickel and 11 pbw molybdenum per 100 pbw
alumina in the second stage. The first stage of the catalytic hydro-
treatment was conducted at an average temperature of 420C, a hydrogen
partial pressure of 150 bar and a space velocity of 1.75 kg.1 .h
and a hydrogen-to-feed ratio of 1000 Nl.kg 1. The second stage of
the catalytic hydrotreatment was conducted at an average temperature
of 425C, a hydrogen partial pressure of 150 bar, a space velocity
of 1.9 kg.l .h and a hydrogen-to-feed ratio of 1500 Nl.kg
The deasphalting was carried out at 145C and 41 bar with butane
as the solvent and at a solvent-to-oil weight ratio of 4:1.
EXAMPLE
With 100 pbw of the 370C atmospheric distillation residue (7)
as the starting material, the quantities of the various streams were
as follows:
3.2 pbw hydrogen (9),
11.3 pbw C4 fraction + H2S (10),
102.6 pbw liquid product (11),
9.7 pbw C5-200C gasoline fraction (12),
18.2 pbw 200-370C middle distillate fraction (13),
74.7 pbw 370C residue (14),
39.4 pbw 370-520C vacuum distillate (15),
35.3 pbw 520C vacuum residue (16),
23.8 pbw deasphalted oil (17),
11.5 pbw asphalt (18),
10.7 pbw portion (8),
o.8 pbw portion (19),
9.7 pbw C4 fraction (22),
30.2 pbw C5-200C gasoline fraction (23),
10.1 pbw 200-370C middle distil]ate fraction (24), and
9.4 pbw 370C residue (25).
