Note: Descriptions are shown in the official language in which they were submitted.
21S0205
SPECIFICATION N-9503
TITLE OF THE INVENTION
PROCESS FOR HYDROTREATING HEAVY HYDROCARBON OIL
BACKGROUND OF THE INVENTION
- 5 1. Field of the Invention
This invention relates to a process for
hydrotreating a heavy hydrocarbon oil (or so-called heavy
hydrocarbon oil feedstock) with greatly reduced carbonaceous
material formation, and more particularly, to a process for
hydrotreating a heavy hydrocarbon oil wherein the formation
of carbonaceous material can be reduced by incorporating a
small amount of specific additive oil into the heavy
hydrocarbon oil.
2. Background Art
A problem associated with the conventional process
for the hydrotreatment of asphaltene-containing heavy
hydrocarbon oils, such as atmospheric residual oils or vacuum
residual oils, is the formation of carbonaceous material
(coke) which causes clogging of heat exchangers thereby
increasing the pressure drop of preheaters and deactivating
the catalyst, thus deteriorating the quality of the product.
Several reports have appeared, showing that the
hydrotreatment of a heavy hydrocarbon oil ln the presence of
a hydrogen-donating substance is effective for controlling
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the formation of coke. Recycling of part of the hydrotreated
oil from the reactor has been practiced in this respect;
however, in these conventional processes, a great amount of
hydrogen-donating substance needs to be added or recycling of
a great amount of hydrotreated oil is required, in addition
to the fact that the effect of these additives for
controlling the formation of coke is still insufficient.
A principal object of the present invention is to
provide an improved process for hydrotreating a heavy
hydrocarbon oil so that remarkably less carbonaceous material
(coke) will form thereby allowing the hydrotreating operation
to continue for longer periods of time in a stable state and
to solve the problems associated with the formation of coke.
SUMMARY OF THE INVENTION
The applicant of the invention has intensively
researched to solve the foregoing problems, and as a result,
has found that the formation of carbonaceous material may be
greatly reduced by incorporating a small amount of specific
additive oil into the heavy hydrocarbon oil. The present
inventions are based on this finding.
That is, the first aspect of the present invention
is directed to a process for hydrotreating a heavy
hydrocarbon oil, wherein the process comprises hydrotreating
a mixed oil of the heavy hydrocarbon oil and at least one
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additive oil in an amount of 0.3 to 15% by weight with
respect to the feedstock at a temperature of 330 to 460C, a
hydrogen partial pressure of 50 to 250 Kg/cm , a liquid
hourly space velocity (LHSV) of 0.1 to 4.0 hr in the
presence of a hydrotreating catalyst, the additive oil being
selected.from the group consisting of coal-tar oils, tar-sand
oils, oil shale- or bitumen-derived oils, and oils obtained
by coal liquefaction.
The second aspect of the invention is directed to a
process for hydrotreating a heavy hydrocarbon oil, wherein
the process comprises hydrotreating a mixed oil of the heavy
hydrocarbon oil and at least one partially aromatic
ring-hydrogenated additive oil in an amount of 0.3 to 15% by
weight with respect to the heavy hydrocarbon oil, at a
temperature of 330 to 460C, a hydrogen partial pressure of
50 to 250 Kg/cm , a liquid hourly space velocity (LHSV) of
0.1 to 4.0 hr in the presence of a hydrotreating catalyst,
the additive oil being selected from the group consisting of
coal-tar oils, tar-sand oils, oil shale- or bitumen-derived
oils, and oils obtained by coal liquefaction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in further
detail hereinbelow.
The term "heavy hydrocarbon oil" refers to a
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petroleum hydrocarbon oil, 50% by weight or more of which
boils at 350C or higher. Examples of such heavy hydrocarbon
oils include atmospheric residual oils obtained by topping
crudes, and vacuum residual oils obtained from the
atmospheric residual oils by vacuum distillation.
The term "hydrotreating" refers to one of those
including hydrodesulfurization, hydrodemetallization,
hydrodenitrogenation and hydrocracking.
The hydrotreating is usually performed at a
temperature of 330 to 460C, preferably at 360 to 440C, more
preferably at 380 to 420C, and a hydrogen partial pressure
of 50 to 250 Kg/cm , preferably 70 to 200 Kg/cm , more
preferably 100 to 150 Kg/cm in the presence of a catalyst.
Usually an LHSV of 0.1 to 4.0 hr , preferably 0.2 to 1.0 hr
may be employed.
In the hydrotreating of the present invention, any
conventional hydrotreating catalyst may be used. Examples of
the catalyst include a catalyst comprising particles
containing one or more of the metals selected from Group V
through Group VIII metal components of the Periodic Table
supported on carrier particles such as alumina,
silica-alumina, or a cationic exchange zeolite. Oxides or
sulfides of these metals may be also used. Examples of these
metals include nickel, cobalt, molybdenum, vanadium, wolfram,
and mixtures thereof.
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Any type of hydrotreating reactor such as a
fixed-bed, moving-bed, or fluidized-bed may be employed.
In the present invention, an additive oil selected
from the group consisting of coal-tar oils, tar-sand oils,
oil shale- or bitumen-derived oils, and oils obtained by coal
liquefaction is added to the heavy hydrocarbon oil, 50~ by
weight or more of the additive oil boiling at 250C or
higher, preferably at 250 to 600C. Preferred percentage (~)
of the aromatic carbons of the additive oil is 60 or more.
The additive oil may be employed as mixtures thereof.
Further, instead of oils obtained by coal liquefaction,
powdered coal before liquefaction may be employable in the
present invention.
According to the first aspect of the present
invention, there is provided a process for hydrotreating a
heavy hydrocarbon oil wherein an additive oil selected from
the group consisting of coal-tar oils, tar-sand oils, oil
shale- or bitumen-derived oils, and oils obtained by coal
liquefaction is blended with the heavy hydrocarbon oil
without any pretreatment, such as a thermal treatment, of the
additive oil.
The additive oil is present in an amount of 0.3 to
15~ by weight, preferably 0.5 to 8% by weight on the basis of
the heavy hydrocarbon oil.
Although any blending technique may be used, the
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foregoing additive oil is preferably fed into the reactor
separately from the heavy hydrocarbon oil or after being
blended with the heavy hydrocarbon oil.
According to the second aspect of the present
invention, there is provided a process for hydrotreating a
heavy hydrocarbon oil wherein the foregoing additive oil is
partially aromatic ring-hydrogenated prior to being charged
into the hydrotreating reactor.
The partial hydrogenation of aromatic rings is
carried out so that a percentage of the aromatic carbon atom
of the resulting hydrogenated oil will be within the range of
from 5 to 50~, preferably 10 to 40%. The foregoing
percentage is represented by the following formula (1):
Percentage (%) of aromatic carbon atom =
(Number of aromatic ring carbon atoms present in given oil
amount (g))/(Total number of carbon atoms present in given
oil amount (g))xlOO ................................. (1)
Any method for the partial hydrogenation of
aromatic rings may be used. Usually the aromatic rings are
partially hydrogenated in the presence of a hydrogenation
catalyst in a pressurized hydrogen atmosphere.
Any conventional hydrogenation catalyst such as one
suitable for use in hydrotreating a petroleum fraction may be
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used herein. More particularly, a catalyst comprising
particles containing one or more of the metals selected from
Group V through Group VIII metal components of the Periodic
Table supported on inorganic carrier particles is employed.
Oxides or sulfides of these metal components may also be
used. Examples of such metal components include nickel,
cobalt, molybdenum, vanadium, and wolfram. Examples of such
inorganic carriers include alumina, silica-alumina, a cation
exchange zeolite, kieselguhr, and the like.
Aromatic ring-hydrogenation catalysts may also be
preferably employed. Examples of the catalyst include a
catalyst comprising particles containing one or more of the
metal components, such as nickel, nickel oxide,
nickel-copper, platinum, platinum oxide, platinum-rhodium,
platinum-lithium, rhodium, palladium, cobalt, ruthenium, or
Raney-cobalt, supported on inorganic carrier particles.
Examples of such inorganic carriers include active carbon,
alumina, silica-alumina, kieselguhr, zeolite, and the like.
Preferred conditions for partially hydrogenating
aromatic rings are as follows: a temperature of 300 to ~00C
and a pressure of 30 to 150 Kg/cm , when a catalyst for use
in hydrotreating a petroleum fraction is employed; a
temperature of 150 to 300C and a pressure of 30 to 150
kg/cm , when a catalyst for use in hydrogenating aromatic
rings is employed.
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Any type of apparatus such as a fixed-bed,
moving-bed, fluidized-bed or a batch type apparatus may be
employed.
The partially aromatic ring-hydrogenated oil thus
obtained is charged into a hydrotreating reactor.
The partially aromatic ring-hydrogenated oil to be
added to the heavy hydrocarbon oil is present in an amount of
0.3 to 15% by weight, preferably 0.5 to 8% by weight with
respect to the weight of the heavy hydrocarbon oil. The
hydrogenated oil may be charged into the reactor separately
from the heavy hydrocarbon oil, or charged after being
blended with the heavy hydrocarbon oil.
The partially aromatic ring-hydrogenated oil
according to the present invention has remarkable
hydrogen-donating properties, and can effectively control the
formation of carbonaceous material even when added to the
heavy hydrocarbon oil in a small amount.
In addition, the specific oil as an additive in
accordance with the present invention is further converted to
aromatic ring-hydrogenated substances of high
hydrogen-donating activity in the hydrogenation reactor,
whereby the formation of carbonaceous material can be reduced
likewise.
The invention will be further illustrated by the
following examples but in no way limited by the examples.
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EXAMPLE 1
A Middle East topped crude having properties as
specified in Table 1 was treated in a downward fixed-bed
reactor (internal diameter; 10 mm, height; 0.5 m, catalyst
volume; 30 cm ) in the presence of a commercially available
Ni-Mo/silica-alumina catalyst at a temperature of 413C, a
hydrogen partial pressure of 165 atm, and a LHSV of 0.50
hr~1. In this experiment, an additive oil obtained by the
procedure that follows was added to the heavy hydrocarbon oil
in an amount of 3% by weight with respect to the heavy
hydrocarbon oil.
That is, the foregoing specific additive oil was
obtained from a decrystallized anthracene oil by removing the
fraction boiling up to 250C. The resulting oil was
determined to contain 89~ by weight aromatic carbons.
The hydrotreating was continued for about 260 hr.
The properties, amount of dried sludge and toluene insolubles
of the resulting product after 240 hr are set forth in Table
2.
EXAMPLE 2
The procedure in Example 1 was followed with the
exception that an additive oil obtained by the procedure that
follows was added to the heavy hydrocarbon oil in an amount
of 3% by weight with respect to the heavy hydrocarbon oil.
~ 1 5020~
That is, the additive oil was obtained by
hydrogenating the substance used as the additive oil in
Example 1 at a temperature of 380C, a hydrogen partial
pressure of 120 atm for 40 min in the presence of a
commercially available hydrodesulfurization catalyst
(Co-Mo/alumina type) in an autoclave. The resulting
hydrotreated additive oil was added to the heavy hydrocarbon
oil without further removing the low-boiling fractions. The
additive oil thus obtained was determined to contain 31% by
weight aromatic carbons by means of H-NMR and C-NMR.
The properties, amount of dried sludge and toluene
insolubles of the resulting product are set forth in Table 2.
EXAMPLE 3
The procedure in Example 1 was followed with the
exception that an additive oil obtained by the procedure that
follows was added.
That is, the additive oil was obtained by
distilling a tar-sand oil to recover the fraction boiling at
between 300 and 550C. The additive oil was determined to
contain 82% by weight aromatic carbons.
The properties, amount of dried sludge and toluene
insolubles of the resulting product are also set forth in
Table 2.
-- 10 --
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EXAMPLE 4
The procedure in Example 1 was followed with the
exception that an additive oil obtained by the procedure that
follows was added in an amount of 1.5% by weight with respect
to the heavy hydrocarbon oil feedstock.
That is, the additive oil was obtained by
hydrogenating the substance used as the additive oil in
Example 3 in an autoclave at 350C, a hydrogen partial
pressure of 130 atm for 60 min in the presence of a
commercially available catalyst (Co-Mo/alumina type) for use
in hydrodesulfurizing a petroleum fraction.
Fractions boiling below 300C were removed from the
resulting hydrotreated oil by distillation. The additive oil
thus obtained was determined to contain 32% aromatic carbons
by means of H-NMR and C-NMR.
The properties, amount of dried sludge and toluene
insolubles of the resulting product are also set forth in
Table 2.
COMPARATIVE EXAMPLE 1
The procedure in Example l was followed, but
without addition of the additive oil.
The properties, amount of dried sludge and toluene
insolubles of the resulting product are also set forth in
Table 2.
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Table 1
Heavy Hydrocarbon Oil Arabian Heavy Atmospheric
Feedstock Residual Oil (Topped Crude)
Density (15C) 0.995
Viscosity (cSt, 50C) 4.120
Conradson Carbon Residue 15.0
(% by weight)
n-Heptane Insolubles 0.95
(% by weight)
Distillation Characteristics
( C)
IBP 276
5/10% 380/413
20/30 453/488
40/50 534/553
S (% by weight) 4.40
N (ppm by weight) 2400
V (ppm by weight) 93
Ni (ppm by weight) 35
Table 2
Properties of Hydrotreated Product Oils
Examples Compr.
Exam.
1 2 3 4
Density (15C) 0.992 0.989 0.983 0.989 0.980
Desulfurization 94.2 94.6 94.0 94.0 95.1
(%)
Demetallization 95.1 96.0 95.2 95.0 96.5
(V, Ni, %)
Amount of dried 0.06 0.05 0.07 0.04 0.71
sludge
(~ by weight)
Toluene 0.04 0.03 0.04 0.02 0.20
Insolubles
(% by weight)
EXAMPLE 5
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A Middle East vacuum residual oil (Table 3) was
hydrocracked at 415C, a hydrogen partial pressure of 170
atm, and a LHSV of 0.3 hr~~ in the presence of a commercially
available hydrocracking catalyst (Ni-Co-Mo/silica-alumina
type) in the same apparatus and the same catalyst volume as
used in Example 1. A 250-600C fraction obtained from a
bitumen-derived oil by distillatlon was added to the heavy
hydrocarbon oil in an amount of 2.5% by weight with respect
to the heavy hydrocarbon oil.
The properties, amount of dried sludge and toluene
insolubles of the resulting hydrocracked product are set
forth in Table 4.
COMPARATIVE EXAMPLE 2
The procedure in Examples 5 was followed, but
without addition of the additive oil.
The properties, amount of dried sludge and toluene
insolubles of the resulting hydrocracked product are also set
forth in Table 4.
- 13 -
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Table 3
Heavy Hydrocarbon OilArabian Heavy Vacuum
Feedstock Residual Oil
Density (15C) 1.030
Viscosity (cSt, 120C) 924.2
Conradson Carbon Residue22.31
(% by weight)
n-Heptane Insolubles 8.4
(% by weight)
S (% by weight) 5
N (ppm by weight) 4030
V (ppm by weight) 140
Ni (ppm by weight) 47
Table 4
Properties of Hydrocracked Product Oils
Example Compr.
Example
Density (15C) 0.990 0.987
% of Cracking (565C) 85 82
Desulfurization (%) 81 84
Demetallization (V, Ni, %) 87 90
Amount of dried sludge 0.09 1.58
(% by weight)
Toluene Insolubles 0.07 0.41
(% by weight)
As is evident from the results in Comparative
Example 1 as set forth in Table 2, when an Arabian Heavy
atmospheric residual oil is severely hydrotreated, a
significant amount of carbonaceous material forms; however,
when an additive oil in accordance with the present invention
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is added to the heavy hydrocarbon oil in an amount of 1.5% by
weight, the amount of dried sludge and toluene insolubles can
be reduced greatly. Although partially hydrogenated additive
oils (Examples 2 and 4) of the present invention prove more
effective for controlling the formation of coke than additive
oils not previously hydrogenated, a fairly good controlling
effect on the formation of coke can be observed even when the
additive oil of the invention is added without being
hydrogenated in advance (Examples 1 and 3).
In addition, it is also found that additive oils of
the present invention produce the intended effect when an
Arabian Heavy vacuum residual oil is hydrocracked as shown in
table 4.
