Technical Field
[0001] The present invention relates to a method for hydrorefining a hydrocarbon oil. More
particularly, the present invention relates to a hydrocarbon oil hydrorefining method
for effectively hydrorefining a heavy hydrocarbon oil contained in an oil mixture,
the oil mixture containing the heavy hydrocarbon oil and a specific hydrocarbon oil.
Background Art
[0002] In a conventional crude oil refining method, generally, crude oil is separated into
fractions through atmospheric distillation, and then each fractions are subjected
to desulfurization. However, such a method is not necessarily satisfactory, since
the method poses problems in that, for example, it requires a large number of oil-refining
facilities, intricate processes, and excessive energy due to repeated cooling and
heating of products. Therefore, demand has arisen for a new crude oil processing method.
From such viewpoints, in recent years, attempts have been made to process crude oil
or naphtha-fraction-free crude oil in one batch. For example, there have been proposed
(1) a method in which a naphtha fraction is separated from crude oil through distillation,
and the resultant naphtha-free residual oil is subjected to hydrodesulfurization all
together and then separated into products through distillation (Patent Document 1);
and (2) a method in which a naphtha fraction is separated from crude oil through distillation,
and the resultant naphtha-free residual oil is subjected to hydrodesulfurization all
together and then separated into a light oil fraction and a heavy oil fraction by
means of a high-pressure separation vessel, followed by hydrorefining of the light
oil fraction (Patent Document 2). Such methods proposed above, in which an oil mixture
containing two or more oil fractions is subjected to hydrotreatment, could achieve
effective hydrorefining.
[0003] Meanwhile, there has been proposed a method for facilitating desulfurization and
demetallization of heavy oil, which have been conventionally difficult to perform,
through dilution of the heavy oil. For example, Patent Document 3 discloses a method
in which residual oil is mixed with a diluent having a specific boiling point, and
the mixture is subjected to desulfurization and demetallization under specific conditions.
According to this method, desulfurization rate and/or demetallization rate increases,
thereby effectively lowering the sulfur and/or metal content of the hydrotreated residual
oil.
[0004] The aforementioned techniques; i.e., techniques employing a feedstock containing
two or more oil fractions, and the technique of diluting heavy oil, are very important
for enhancing performance in hydrorefining. However, from the viewpoints of environmental
issues and energy savings, a hydrorefining process of further enhanced performance
must be developed. The technique disclosed in Patent Document 3 is not necessarily
effective in terms of energy savings. Specifically, the technique leaves room for
improvement in terms of energy savings in the overall process of crude oil refining,
since the technique employs, as a low-boiling-point diluent which is mixed with heavy
oil, for example, light oil or distilled oil, which can be generally refined within
a shorter period of time under mild conditions, as compared with the case of the heavy
oil.
[0005] Regarding the aforementioned conventional techniques; i.e., techniques employing
a feedstock containing two or more oil fractions, and techniques of diluting heavy
oil, the effect of mixing a plurality of types of oil has not yet been elucidated
in detail. Therefore, difficulty is encountered in improving the conventional techniques
and developing a new oil refining method, even under the circumstances that such improvement
and development are required.
[0006]
Patent Document 1: Japanese Patent Application Publication (kokai) No. H03-294390
Patent Document 2: Japanese Patent Application Publication (kokai) No. H04-224890
Patent Document 3: Japanese Patent Application Publication (kokai) No. H04-239094
Disclosure of the Invention
Problems to be Solved by the Invention
[0007] Under such circumstances, an object of the present invention is to provide a hydrocarbon
oil hydrorefining method which, in hydrorefining of a hydrocarbon oil containing heavy
oil, can enhance performance in hydrorefining of the heavy oil, to thereby produce
an increased amount of a refined oil, to produce a high-quality refined oil, and to
attain mild hydrorefining conditions. Means for Solving the Problems
[0008] As has been known, in hydrodesulfurization reaction, there is a difference in processing
rate between a heavy hydrocarbon oil and a light hydrocarbon oil. In general, a heavy
hydrocarbon oil is processed at very low efficiency, as compared with the case of
a light hydrocarbon oil. Thus, conceivably, when a mixture of a heavy hydrocarbon
oil and a light hydrocarbon oil is subjected to hydrodesulfurization, hydrodesulfurization
reaction of the light hydrocarbon oil is completed in the vicinity of an inlet of
a reactor, and, after completion of the reaction, the light hydrocarbon oil serves
as an inert diluent. Therefore, since the heavy hydrocarbon oil is mixed with the
light hydrocarbon oil, even when LHSV increases, desulfurization conversion of the
heavy hydrocarbon oil does not decrease, and desulfurization proceeds effectively
(hereinafter, this effect of the light hydrocarbon oil may be referred to as the "dilution
effect"). However, such a hydrodesulfurization technique leaves room for improvement
in terms of energy savings in the overall process of crude oil refining, since, as
described above, the light hydrocarbon oil can be refined within a shorter period
of time under mild conditions, as compared with the case of the heavy hydrocarbon
oil. In view of the foregoing, the present inventors have conducted extensive studies,
and as a result have found that when a specific light hydrocarbon oil is added to
a heavy hydrocarbon oil, and the mixture is processed through a specific method, effects
other than the aforementioned dilution effect can be obtained, and hydrorefining can
be carried out more effectively. The present invention has been accomplished on the
basis of this finding. Accordingly, the present invention provides the following:
- (1) a hydrocarbon oil hydrorefining method, characterized by comprising providing
a mixture of a heavy hydrocarbon oil and a dissolved-hydrogen-concentration-increasing
hydrocarbon oil (i.e., a hydrocarbon oil exhibiting an effect of increasing the concentration
of dissolved hydrogen); mixing the oil mixture, which is subjected to hydrorefining,
with hydrogen; and causing the resultant mixture to pass through a reactor for carrying
out hydrorefining;
- (2) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
oil mixture of a heavy hydrocarbon oil and a dissolved-hydrogen-concentration-increasing
hydrocarbon oil has a dissolved hydrogen concentration which is 1.1 times or more
the highest possible hydrogen concentration of the heavy hydrocarbon oil;
- (3) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
heavy hydrocarbon oil is one or more species selected from among vacuum residual oil,
vacuum gas oil, atmospheric residual oil, topped crude oil, crude oil, deasphalted
oil, coal-liquefied oil, oil obtained from oil sand, and oil obtained from oil shale;
- (4) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
dissolved-hydrogen-concentration-increasing hydrocarbon oil is contained in a liquid
phase entirely or partially under the conditions in the reactor;
- (5) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
effect of increasing dissolved hydrogen concentration is estimated on the basis of
the equilibrium of hydrogen between gas and liquid in the reactor;
- (6) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
dissolved-hydrogen-concentration-increasing hydrocarbon oil is additionally fed, as
a quenching oil, into the reactor;
- (7) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
dissolved-hydrogen-concentration-increasing hydrocarbon oil is one or more species
selected from among a straight-run kerosene fraction, a straight-run light gas oil
fraction, a straight-run heavy gas oil fraction, cracked oil obtained from an FCC
unit, and thermally cracked oil obtained from a coker unit;
- (8) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
hydrorefining includes one or more steps selected from among a hydrodemetallization
step, a hydrodesulfurization step, a hydrocracking step, a hydrodenitrogenation step,
and a hydrodearomatization step;
- (9) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
hydrorefining is carried out under the following conditions: a reaction temperature
of 300 to 450°C, a hydrogen partial pressure of 5.1 to 25.3 MPa(G), a hydrogen/oil
ratio of 200 to 2,000 Nm3/kL, and an LHSV of 0.05 to 10 hr-1; and
- (10) a hydrocarbon oil hydrorefining method as described in (1) above, wherein the
hydrorefining is carried out under the following conditions: a reaction temperature
of 330 to 430°C, a hydrogen partial pressure of 10.1 to 20.3 MPa(G), a hydrogen/oil
ratio of 500 to 1,000 Nm3/kL, and an LHSV of 0.1 to 1.0 hr-1.
Effects of the Invention
[0009] According to the present invention, there is provided a hydrocarbon oil hydrorefining
method which, in hydrorefining of a hydrocarbon oil containing heavy oil, can further
enhance performance in hydrorefining of the heavy oil, to thereby produce an increased
amount of a refined oil, to produce a high-quality refined oil, and to attain mild
hydrorefining conditions. The hydrorefining method comprises adding a specific light
hydrocarbon oil to a heavy hydrocarbon oil, and processing the resultant mixture under
specific conditions. Therefore, according to the hydrorefining method, a defect that
the light hydrocarbon oil is subjected to hydrorefining for a long period of time
under severe conditions is solved and the energy savings can be achieved in the overall
process of crude oil.
Brief Description of the Drawings
[0010]
[Fig. 1]
Fig. 1 schematically shows a diagram of steps included in the present invention.
[Fig. 2]
Fig. 2 schematically shows another diagram of steps included in the present invention.
[Fig. 3]
Fig. 3 schematically shows still another diagram of steps included in the present
invention.
[Fig. 4]
Fig. 4 schematically shows yet another diagram of steps included in the present invention.
Description of Reference Numerals
[0011]
- 1:
- Hydrodemetallization step
- 2:
- Hydrodesulfurization step
- 3:
- Separation-refinement step
- 4:
- Hydrocracking step
- 5:
- Hydrodenitrogenation step
- 6:
- Bottom oil recycling
- 7:
- Hydrogen recycling
- 8:
- Quenching hydrogen
- 9:
- Quenching oil
- 11:
- Heavy hydrocarbon oil
- 12:
- Dissolved-hydrogen-concentration-increasing hydrocarbon oil
- 13:
- Hydrogen
- 14:
- Refined heavy hydrocarbon oil
- 15:
- Refined light hydrocarbon oil
Best Modes for Carrying Out the Invention
[0012] In the hydrocarbon oil hydrorefining method of the present invention, hydrogen is
mixed with an oil mixture containing a heavy hydrocarbon oil and a dissolved-hydrogen-concentration-increasing
hydrocarbon oil, and the hydrogen-mixed oil mixture is caused to pass through a reactor
for carrying out hydrorefining.
[0013] The heavy hydrocarbon oil may be selected from among vacuum residual oil, vacuum
gas oil, atmospheric residual oil, topped crude oil, crude oil, deasphalted oil, coal-liquefied
oil, oil obtained from oil sand, and oil obtained from oil shale, and these oils may
be employed singly or in combination of two or more species. Since effects of the
present invention are difficult to obtain when a heavy hydrocarbon oil incapable of
forming a liquid phase in the reactor is employed, an appropriate heavy oil must be
selected, or appropriate reaction conditions must be provided. The present invention
is intended to achieve enhancement of performance in heavy hydrocarbon oil hydrorefining,
which has been conventionally difficult to attain. Therefore, the heavy hydrocarbon
oil employed in the present invention preferably contains asphaltene (as used herein,
"asphaltene" refers to an n-heptane-insoluble fraction of heavy oil obtained through
extraction of the heavy oil with n-heptane) in an amount of 2 mass% or more, more
preferably 4 mass% or more.. Even when a heavy hydrocarbon oil having an asphaltene
content of less than 2 mass% is employed, the resultant refined oil exhibits no problematic
features. However, employment of such a low-asphaltene-content heavy hydrocarbon oil
is not preferred from the viewpoints of cost-effectiveness and energy savings, since
the heavy hydrocarbon oil is relatively easily hydrogenated without application of
the present invention. No particular limitation is imposed on the maximum asphaltene
content of the heavy hydrocarbon oil employed in the present invention, but the asphaltene
content is preferably less than 15 mass%, from the viewpoint of operation of the reactor.
For reasons similar to those described above, the heavy hydrocarbon oil employed in
the present invention preferably contains vanadium in an amount of 10 mass ppm or
more, nickel in an amount of 10 mass ppm or more, and sulfur in an amount of 0.1 mass%
or more.
[0014] The heavy hydrocarbon oil employed is preferably pretreated as desired. For example,
when the heavy hydrocarbon oil has a high salt content, preferably, the hydrocarbon
oil is subjected to desalting treatment so as to have a sodium chloride content of
10 mass ppm or less. When the heavy hydrocarbon oil has a high solid content, the
hydrocarbon oil is preferably filtered with a filter (about 10 µm).
[0015] The present invention employs a dissolved-hydrogen-concentration-increasing hydrocarbon
oil. As used herein, "dissolved-hydrogen-concentration-increasing hydrocarbon oil"
refers to a hydrocarbon oil which has an average boiling point of 100°C or higher,
which has a density of 0.70 to 0.95 g/mL, and which exhibits the effect of increasing
the dissolved hydrogen concentration of the resultant oil mixture so that the dissolved
hydrogen concentration of the oil mixture as measured under the conditions (temperature
and pressure) becomes higher than the highest possible hydrogen concentration of the
heavy hydrocarbon oil as measured at the same conditions. When a hydrocarbon oil having
an average boiling point lower than 100°C or a density lower than 0.70 g/mL is employed,
the amount of the hydrocarbon oil present in a liquid phase is considerably reduced,
and the hydrocarbon oil tends to exhibit poor effect of increasing hydrogen concentration.
Also, a hydrocarbon oil having a density higher than 0.95 g/mL tends to exhibit poor
effect of increasing dissolved hydrogen concentration. Specific examples of the dissolved-hydrogen-concentration-increasing
hydrocarbon oil include a straight-run kerosene fraction, a straight-run light gas
oil fraction, a straight-run heavy gas oil fraction, cracked oil obtained from an
FCC unit, and thermally cracked oil obtained from a coker unit. These may be employed
singly or in combination of two or more species. The present invention may employ
a non-petroleum-origin hydrocarbon. In general, a light hydrocarbon having a boiling
point lower than that of the heavy hydrocarbon oil serving as a starting oil exhibits
the effect of increasing the dissolved hydrogen concentration of a liquid phase in
the reactor. However, when a light hydrocarbon having a very low boiling point is
excessively fed into the reactor, since the light hydrocarbon is generally present
in a gas phase in the reactor, the hydrogen partial pressure in the gas phase is reduced,
and the light hydrocarbon may fail to exhibit an effect of increasing dissolved hydrogen
concentration.
[0016] The aforementioned dissolved-hydrogen-concentration-increasing hydrocarbon oil must
be present in a liquid phase entirely or partially under the temperature and pressure
conditions in the reactor. When the hydrocarbon oil is entirely or partially present
in the liquid phase, hydrorefining performance can be enhanced. Under the temperature
and pressure conditions in the reactor, the ratio of the amount of the hydrocarbon
oil present in the liquid phase to the entire amount of the hydrocarbon oil is preferably
10% or more, more preferably 20% or more.
[0017] When the dissolved-hydrogen-concentration-increasing hydrocarbon oil is subjected
to hydrorefining together with the heavy oil, hydrorefining performance can be further
enhanced by effects other than the aforementioned dilution effect. In the present
invention, preferably, the mixture of the heavy hydrocarbon oil and the dissolved-hydrogen-concentration-increasing
hydrocarbon oil has a dissolved hydrogen concentration which is 1.1 times or more
the highest possible hydrogen concentration of the heavy hydrocarbon oil. When the
dissolved hydrogen concentration is less than 1.1 times the highest possible hydrogen
concentration of the heavy hydrocarbon oil, since the dissolved-hydrogen-concentration-increasing
hydrocarbon oil (e.g., a light hydrocarbon oil) must be subjected to hydrorefining
for a long period of time under severe conditions, problems are likely to arise in
terms of production cost and energy savings in the overall process of crude oil refining.
For the aforementioned reasons, the light hydrocarbon oil is fed so that the dissolved
hydrogen concentration of the hydrocarbon oil mixture is elevated to more preferably
1.15 times or more, much more preferably 1.2 times or more, the highest possible hydrogen
concentration of the heavy hydrocarbon oil.
[0018] In the present invention, the dissolved-hydrogen-concentration-increasing hydrocarbon
oil may be selected by means of a tool which can estimate dissolved hydrogen concentration
and the equilibrium of hydrogen between gas and liquid in the reactor. Now will be
specifically described the case where a process simulator Pro/II (ver. 6.01) (product
of Invensys Process Systems) is employed.
[0019]
- (1) A mixer and a flusher (located downstream of the mixer) are selected from a PFD
process unit.
- (2) Hydrogen is selected as a fluid fed through an inlet of the mixer, and the feed
rate of hydrogen is input.
- (3) Petroleum (Petroleum Assay) is selected as a type of fluid fed through another
inlet of the mixer, and the feed rate, density (g/cm3), and distillation characteristics of a heavy hydrocarbon oil which is fed are input.
- (4) Conditions (temperature and pressure) of the flusher for separation are input.
- (5) The SRK equation (SRK01) is selected from among general thermodynamic equations,
and employed for obtaining thermodynamic data [the SRK equation is one of the most
commonly used thermodynamic equations in process simulators in the field of petroleum
refining].
- (6) Through calculation by means of the process simulator, the mass flow rate of hydrogen
contained in a liquid phase at an outlet of the flusher was divided by the total mass
flow rate of the liquid phase at the outlet of the flusher, and the hydrogen content
(wt.%) of the liquid phase is determined, to thereby estimate the dissolved hydrogen
concentration of the liquid phase at an inlet of the reactor in the case where the
heavy hydrocarbon oil is fed singly.
In a manner similar to that described above, in step (3), a light hydrocarbon oil
is selected as a fluid which is fed, in addition to the heavy hydrocarbon oil, through
the inlet of the mixer, and the feed rate, density, and distillation characteristics
of the light hydrocarbon oil are input. Thereafter, calculation is performed in a
manner similar to that described above. Comparison of the resultant data with the
above-obtained data can determine a change in dissolved hydrogen concentration of
the liquid phase in the reactor in the case where the light hydrocarbon oil is fed
under certain conditions. Through this procedure, the dissolved hydrogen concentration
of the liquid phase at the inlet of the reactor is estimated.
[0020] In order to estimate the dissolved hydrogen concentration of the liquid phase at
the outlet of the reactor in the case where hydrorefining reaction is actually carried
out, in step (2), the composition and discharge rate of offgas are input, and, in
step (3), the density, distillation characteristics, and recovery rate of the thus-refined
oil are input. In addition to the SRK equation, the PR equation or the GS equation
may be employed as a thermodynamic equation. It was previously found that when the
mixture of the heavy hydrocarbon oil and the light hydrocarbon oil is caused to pass
through the reactor, and an increase in dissolved hydrogen concentration of the liquid
phase is determined by use of each of these three equations, there is no difference
between data obtained by use of these equations. Even when the composition of offgas
discharged from the outlet of the reactor is unknown, the dissolved hydrogen concentration
of the liquid phase may be estimated only on the basis of parameters of the fluid
fed through the inlet of the reactor.
[0021] In addition, the optimum mixing ratio of the heavy hydrocarbon oil to the dissolved-hydrogen-concentration-increasing
hydrocarbon oil may be estimated by means of the aforementioned process simulator.
When hydrorefining reaction conditions are determined on the basis of the effect of
increasing dissolved hydrogen concentration, hydrorefining reaction is readily controlled,
and energy can be saved in hydrorefining.
[0022] The hydrocarbon oil hydrorefining method will next be more specifically described.
In the hydrorefining method of the present invention, a hydrocarbon oil mixture is
mixed with hydrogen, and then the resultant mixture is caused to pass through the
reactor for carrying out hydrorefining. Preferably, the heavy hydrocarbon oil is mixed
with the dissolved-hydrogen-concentration-increasing hydrocarbon oil (e.g., light
hydrocarbon oil), to thereby prepare an oil mixture; the oil mixture is pressurized
and preheated by means of a heat exchanger, and then mixed with hydrogen; the pressurized,
hydrogen-mixed oil mixture is heated to a reaction temperature in a heating furnace;
and the thus-heated oil mixture is fed to the reactor. When the oil mixture is mixed
with hydrogen before being pressurized or subjected to the heat exchange process,
pressurization or heat exchange of the resultant gas-liquid mixture is required, and
performance in pressurization or heating tends to lower. When the oil mixture is mixed
with hydrogen after the oil mixture has been caused to pass through the heating furnace,
the time for dissolving hydrogen in the oil mixture may be insufficient.
[0023] Hydrorefining is carried out under, for example, the conditions of reaction temperature:
300 to 450°C, hydrogen partial pressure: 5.1 to 25.3 MPa(G), hydrogen/oil ratio: 200
to 2,000 Nm
3/kL, and LHSV: 0.05 to 10 hr
-1; or the conditions of reaction temperature: 330 to 430°C, hydrogen partial pressure:
10.1 to 20.3 MPa(G), hydrogen/oil ratio: 500 to 1,000 Nm
3/kL, and LHSV: 0.1 to 1.0 hr
-1.
[0024] Examples of hydrorefining steps include a hydrodemetallization step, a hydrodesulfurization
step, a hydrocracking step, a hydrodenitrogenation step, and a hydrodearomatization
step. No particular limitation is imposed on the hydrotreatment step employed in the
method of the present invention, and the method may employ two or more of the aforementioned
hydrotreatment steps. When the aforementioned hydrotreatment steps are sequentially
carried out, no particular limitation is imposed on the order of the steps, but preferably,
the hydrodemetallization step is carried out first. In general, firstly, the hydrodemetallization
step is carried out; subsequently, the hydrodenitrogenation step, the hydrocracking
step, or a similar hydrotreatment step is carried out; and finally, the hydrodesulfurization
step is carried out. As desired, the hydrocracking step or a similar hydrotreatment
step may be further carried out after the hydrodesulfurization step. No particular
limitation is imposed on the type of reactor employed in any of these hydrotreatment
steps, and, for example, a fixed-bed, moving-bed, fluidized-bed, ebullient bed, or
slurry-bed reactor may be employed. The dissolved-hydrogen-concentration-increasing
hydrocarbon oil may be fed, as a quenching oil, into the reactor.
[0025] The aforementioned hydrodemetallization step is carried out in one or more reactors
after the hydrogen-mixed hydrocarbon oil mixture has been pressurized and heated.
[0026] The catalyst employed in the hydrodemetallization step is preferably a catalyst prepared
by supporting, on a carrier (e.g., a porous inorganic oxide such as alumina, silica,
silica-alumina, or sepiolite, or a natural mineral), an active metal (i.e., at least
one species selected from among metals of Groups 8, 9, and 10 of the periodic table)
and a promoter metal (i.e., at least one species selected from among metals of Group
6 of the periodic table). The active metal content of the hydrodemetallization catalyst
is preferably 2 to 8 mass%, more preferably 2 to 4 mass%, as reduced to metal oxide.
The promoter metal content of the hydrodemetallization catalyst is preferably 0.5
to 5 mass%, more preferably 1 to 5 mass%, as reduced to metal oxide. Specifically,
the active metal (i.e., a metal of Groups 8, 9, and 10 of the periodic table) is more
preferably nickel, cobalt, or rhodium, and the promoter metal (i.e., a metal of Group
6 of the periodic table) is more preferably molybdenum or tungsten. The amount of
the catalyst employed in the hydrodemetallization step may be appropriately determined
in consideration of the metal concentration of the hydrocarbon oil mixture. However,
the amount of the hydrodemetallization catalyst is preferably 10 to 50 vol.% on the
basis of the total amount of the catalysts employed in all the hydrotreatment steps.
[0027] The hydrodemetallization step is preferably carried out under the conditions of
reaction temperature: 300 to 450°C (more preferably 330 to 430°C), hydrogen partial
pressure: 5 to 25 MPa(G) (more preferably 10 to 20 MPa(G)), hydrogen/oil ratio: 200
to 2,000 Nm
3/kL (more preferably 500 to 1,000 Nm
3/kL), and LHSV (liquid hourly space velocity): 0.1 to 20 hr
-1 (more preferably 0.2 to 2 hr
-1). When hydrogen partial pressure and hydrogen/oil ratio are below the above ranges,
reaction efficiency tends to lower, whereas when hydrogen partial pressure and hydrogen/oil
ratio exceed the above ranges, production cost tends to increase. When LHSV is below
the above range, production cost tends to increase, whereas when LHSV exceeds the
above range, reaction efficiency tends to lower.
[0028] The aforementioned hydrodesulfurization step is generally carried out after the hydrodemetallization
step or a similar hydrotreatment step. Therefore, when reaction temperature control
is required, preferably, the reaction temperature is controlled by means of a heat
exchanger, quenching hydrogen gas, or quenching oil. The hydrodesulfurization step
is carried out in one or more reactors.
[0029] The catalyst employed in the hydrodesulfurization step may be a hydrodesulfurization
catalyst generally used for heavy oil; for example, a catalyst prepared by supporting,
on a carrier (e.g., alumina, silica, silica-alumina, zeolite, or a mixture thereof),
at least one species selected from among metals of Groups 5, 6, 8, 9, and 10 of the
periodic table. The carrier preferably has an average pore size of 8 nm or more, and
the supported metal content of the hydrodesulfurization catalyst is preferably 3 to
30 mass% as reduced to metal oxide.
[0030] The hydrodesulfurization step is preferably carried out under the conditions of reaction
temperature: 300 to 450°C (more preferably 330 to 430°C), hydrogen partial pressure:
5 to 25 MPa(G) (more preferably 10 to 20 MPa(G)), hydrogen/oil ratio: 200 to 2,000
Nm
3/kL (more preferably 500 to 1,000 Nm
3/kL), and LHSV (liquid hourly space velocity): 0.1 to 20 hr
-1 (more preferably 0.2 to 2 hr
-1). When reaction temperature, hydrogen partial pressure, and hydrogen/oil ratio are
below the above ranges, reaction efficiency tends to lower, whereas when reaction
temperature, hydrogen partial pressure, and hydrogen/oil ratio exceed the above ranges,
production cost tends to increase. When LHSV is below the above range, production
cost tends to increase, whereas when LHSV exceeds the above range, reaction efficiency
tends to lower.
[0031] The aforementioned hydrocracking step is generally carried out after the hydrodemetallization
step or a similar hydrotreatment step. Therefore, when reaction temperature control
is required, preferably, the reaction temperature is controlled by means of a heat
exchanger, hydrogen-quenching, or oil-quenching. The hydrocracking step is carried
out in one or more reactors.
[0032] The catalyst employed in the hydrocracking step is preferably a catalyst prepared
by supporting, on a carrier made of a mixture of iron-containing aluminosilicate and
alumina, a metal having hydrogenation activity (i.e., at least one species selected
from among metals of Groups 6, 8, 9, and 10 of the periodic table). The metal of Group
6 of the periodic table is preferably tungsten or molybdenum. A plurality of metals
may be employed in combination. Preferably, a combination of nickel-molybdenum, cobalt-molybdenum,
nickel-tungsten, or nickel-cobalt-molybdenum is employed, from the viewpoints of high
hydrogenation activity and low degradation.
[0033] The hydrocracking step is preferably carried out under the conditions of reaction
temperature: 300 to 450°C (more preferably 380 to 420°C), hydrogen partial pressure:
5 to 25 MPa(G) (more preferably 10 to 20 MPa(G)), hydrogen/oil ratio: 200 to 2,000
Nm
3/kL (more preferably 500 to 1,000 Nm
3/kL), and LHSV (liquid hourly space velocity): 0.1 to 20 hr
-1 (more preferably 0.2 to 2 hr
-1). When reaction temperature, hydrogen partial pressure, and hydrogen/oil ratio are
below the above ranges, reaction efficiency tends to lower, whereas when reaction
temperature, hydrogen partial pressure, and hydrogen/oil ratio exceed the above ranges,
production cost tends to increase. When LHSV is below the above range, production
cost tends to increase, whereas when LHSV exceeds the above range, reaction efficiency
tends to lower.
[0034] When vacuum gas oil is subjected to the hydrocracking step, preferably, the aforementioned
hydrodenitrogenation step is carried out before the hydrocracking step. The hydrodenitrogenation
step is carried out in one or more reactors. The hydrodenitrogenation step may be
carried out through a conventionally known method; for example, the method disclosed
in Japanese Patent Application Publication (
kokai) No.
2003-049175.
[0035] The aforementioned hydrodearomatization step is carried out for the purpose of obtaining
a lubricating oil base from a refined oil produced through the aforementioned hydrorefining
steps. The hydrodearomatization step is carried out in one or more reactors. The hydrodearomatization
step is preferably carried out under the conditions of reaction temperature: 300 to
450°C (more preferably 380 to 420°C), hydrogen partial pressure: 10 to 25 MPa(G) (more
preferably 15 to 23 MPa(G)), hydrogen/oil ratio: 200 to 2,000 Nm
3/kL, and LHSV (liquid hourly space velocity): 0.1 to 20 hr
-1 (more preferably 0.2 to 2 hr
-1) When reaction temperature, hydrogen partial pressure, and hydrogen/oil ratio are
below the above ranges, reaction efficiency tends to lower, whereas when reaction
temperature, hydrogen partial pressure, and hydrogen/oil ratio exceed the above ranges,
production cost tends to increase. When LHSV is below the above range, production
cost tends to increase, whereas when LHSV exceeds the above range, reaction efficiency
tends to lower.
[0036] The above-hydrorefined oil is introduced to a separation step according to a customary
method, and is separated into a gas fraction and a liquid fraction through treatment
by means of a plurality of separation vessels. Subsequently, hydrogen sulfide, ammonia,
etc. are removed from the gas fraction, and then the gas fraction is subjected to,
for example, a treatment for increasing hydrogen purity. Thereafter, the resultant
gas fraction is mixed with a fresh feed gas, and then recycled to the reaction step.
The liquid fraction obtained through the separation step is introduced into an atmospheric
separation tower (called "stripper"). Subsequently, hydrogen sulfide by-produced through
desulfurization is removed, and a light oil fraction is separated from the resultant
refined oil.
[0037] Embodiments of the hydrocarbon oil hydrorefining method of the present invention
will now be described with reference to Figs. 1 to 4.
Fig. 1 shows a method in which a light hydrocarbon oil is mixed with atmospheric residual
oil or vacuum residual oil, and is caused to pass through a direct desulfurization
unit for the residual oil (method 1). Fig. 2 shows a refining method (modification
of method 1), wherein the light hydrocarbon oil is also employed as a quenching oil
(method 2). Fig. 3 shows a method in which a light hydrocarbon oil is mixed with atmospheric
residual oil or vacuum residual oil, and is caused to pass through a hydrocracking
unit for the residual oil (method 3). Fig. 4 shows a method in which a light hydrocarbon
oil is mixed with vacuum gas oil, and is caused to pass through a hydrocracking unit
for the vacuum gas oil (method 4). In method 4, bottom oil recycling is not necessarily
carried out. Method 4 (except for the hydrocracking step) can be applied to the case
where a light hydrocarbon oil is mixed with vacuum gas oil, and is caused to pass
through a desulfurization unit for the vacuum gas oil (i.e., a so-called indirect
desulfurization unit).
Examples
[0038] The present invention will next be described in more detail by way of examples, which
should not be construed as limiting the invention thereto.
[0039] Table 1 shows characteristics of heavy hydrocarbon oils serving as feedstock. Tables
2 and 3 show characteristics of hydrocarbon oils serving as mixing oils. Data shown
in the Tables were obtained through the following methods.
(Tables 1 and 2)
[0040] Density: JIS K2249
Sulfur content: JIS K2541 Nitrogen content: JIS K2609 Vanadium content: JPI 5S-10,11
Nickel content: JPI 5S-10,11 Residual carbon content: JIS K2270 Kinematic viscosity:
JIS K2283
(Table 3)
[0041] Specific Gravity: ASTM D2598
Kinematic viscosity: JIS K2283
Vapor pressure: ASTM D1267
[0042] [Table 1]
Table 1
|
Heavy hydrocarbon oil A |
Heavy hydrocarbon oil B |
Heavy hydrocarbon oil C |
Arabian heavy atmospheric residual oil |
Arabian heavy vacuum gas oil |
Arabian heavy vacuum residual oil |
Density (g/mL) |
0.9873 |
0.9171 |
1.0409 |
S content (wt.%) |
4.41 |
2.94 |
5.54 |
N content (wt.ppm) |
2,500 |
740 |
3,760 |
V content (wt.ppm) |
84 |
0.5 |
152 |
Ni content (wt.ppm) |
27 |
0.5> |
50 |
n-Heptane insoluble components (wt.%) |
7.89 |
- |
- |
Conradson's Carbon content (wt.%) |
14.1 |
0.33 |
25.2 |
Distillation characteristics (°C) |
IBP |
340 |
348 |
479 |
5% |
362 |
360 |
527 |
10% |
380 |
370 |
548 |
20% |
418 |
388 |
576 |
30% |
457 |
406 |
601 |
40% |
499 |
425 |
630 |
50% |
543 |
442 |
661 |
60% |
589 |
460 |
688 |
70% |
648 |
478 |
- |
80% |
- |
498 |
- |
90% |
- |
522 |
- |
[0043] [Table 2]
Table 2-1
|
Mixing oil A |
Mixing oil B |
Mixing oil C |
Arabian heavy straight-run kerosene |
Arabian heavy straight-run light gas oil |
Arabian heavy desulfurized gas oil |
Density (g/mL) |
0.7922 |
0.8554 |
0.8339 |
S content (wt.ppm) |
2410 |
13000 |
10 |
N content (wt.ppm) |
1> |
120 |
1> |
Kinematic viscosity (mm2/s, 30°C) |
1.358 |
6.393 |
4.858 |
Monocyclic aromatics (vol.%) |
16.7 |
14 |
16.9 |
Dicyclic aromatics (vol.%) |
0.9 |
9.7 |
2 |
Tricyclic aromatics (vol.%) |
0.1> |
2.5 |
0.1 |
Distillation characteristics (°C) |
IBP |
125 |
200 |
138 |
5% |
160 |
247 |
215 |
10% |
167 |
265 |
238 |
20% |
176 |
281 |
262 |
30% |
185 |
293 |
279 |
40% |
195 |
304 |
290 |
50% |
201 |
313 |
300 |
60% |
210 |
323 |
311 |
70% |
218 |
334 |
322 |
80% |
224 |
346 |
336 |
90% |
234 |
363 |
354 |
95% |
238 |
378 |
370 |
97% |
240 |
380 |
376 |
EP |
248 |
385 |
380 |
Table 2-2
|
Mixing oil D |
Mixing oil E |
R-FCC unit Light cycle oil |
Delayed Coker unit Coker gas oil |
Density (g/mL) |
0.9370 |
0.8496 |
S content (wt.ppm) |
22000 |
22300 |
N content (wt.ppm) |
830 |
440 |
Kinematic viscosity (mm2/s, 30°C) |
4.377 |
4.618 |
Monocyclic aromatics (vol.%) |
21.2 |
19 |
Dicyclic aromatics (vol.%) |
38.1 |
22 |
Tricyclic aromatics (vol.%) |
11.5 |
4 |
Distillation characteristics (°C) |
IBP |
203 |
125 |
5% |
234 |
160 |
10% |
243 |
175 |
20% |
256 |
198 |
30% |
264 |
218 |
40% |
273 |
236 |
50% |
284 |
252 |
60% |
297 |
267 |
70% |
311 |
283 |
80% |
328 |
298 |
90% |
348 |
314 |
95% |
362 |
323 |
97% |
365 |
330 |
EP |
370 |
354 |
[0044] [Table 3]
Table 3
|
Mixing oil F |
Straight-run n-butane |
Specific gravity |
(60/60F) |
0.5847 |
Kinematic viscosity |
(mm2/s, 20°C) |
0.299 |
Vapor pressure |
(kg/cm2, 37.8°C) |
3.9 |
Average molecular weight |
- |
58 |
[0045] Table 4 shows characteristics of catalysts employed in hydrorefining. The alumina-boria
carrier of a hydrodesulfurization catalyst (catalyst B) and the steamed iron-containing
zeolite of a hydrocracking catalyst (catalyst C) were respectively prepared according
to Example 1 of Japanese Patent Application Publication (
kokai) No.
H06-319994 and Example 1 of Japanese Patent Application Publication (
kokai) No.
H02-289419.
[0046] [Table 4]
Table 4
|
Catalyst A |
Catalyst B |
Catalyst C |
Hydrodemetalizing catalyst |
Hydrodesulfurizing catalyst |
Hydrocracking catalyst |
Carrier (wt.%, carrier base) |
Alumina |
100 |
90 |
35 |
Boria |
- |
10 |
- |
Iron-containing aluminosilicate |
- |
- |
65 |
Active metal (wt.%, catalyst base) |
Nickel oxide |
2.3 |
- |
- |
Molybdenum oxide |
8.3 |
14 |
10 |
Cobalt oxide |
- |
3.7 |
4 |
Physical properties |
Specific surface area (m2/g) |
143 |
228 |
445 |
Pore volume (mL/g) |
0.76 |
0.71 |
0.62 |
Mean pore size (Å) |
190 |
124 |
158 |
[Example 1]
[0047] As shown in Table 5, catalyst A (25 mL) and catalyst B (75 mL) were sequentially
loaded into a reaction tube, followed by hydrorefining reaction. In this reaction,
Arabian heavy atmospheric residual oil (heavy hydrocarbon oil A) shown in Table 1
was fed at an LHSV of 0.21 h
-1, and Arabian heavy straight-run kerosene (mixing oil A) shown in Table 2 was fed
so that the total LHSV of the oil mixture was regulated to 0.315 h
-1. Hydrogen partial pressure was maintained at 13.2 MPa(G); hydrogen/oil ratio was
maintained at 800 Nm
3/kL; and reaction temperature was maintained at 380°C. Hydrogen was mixed with the
oil mixture after the oil mixture had been heated to the aforementioned reaction temperature
and before the oil mixture was caused pass through the reactor. The oil mixture was
caused to pass through the reactor for 1,500 hours so as to stabilize hydrogenation
activity, followed by production of a refined oil. The refined oil was subjected to
distillation by means of a 15-stage distillation apparatus according to the method
specified by ASTM D2892-84, to thereby yield fractions. Table 5 shows the percent
cracking, sulfur content, and metal content of an atmospheric residual oil fraction
(boiling point of 343°C or higher) of the refined oil (hereinafter, this residual
oil fraction may be referred to as the "343°C+ fraction").
[Examples 2 to 10]
[0048] The hydrorefining procedure of Example 1 was repeated, except that the feedstock
and the reaction conditions were changed as shown in Table 5. In Example 10, the temperature
of a hydrodemetallization zone and a hydrodesulfurization zone was controlled to 380°C,
and the temperature of a hydrocracking zone was controlled to 400°C.
[Comparative Examples 1 to 5]
[0049] The hydrorefining procedure of Example 1 was repeated, except that hydrocarbon oils
and reaction conditions were changed as shown in Table 6. In Comparative Example 5,
the temperature of a hydrodemetallization zone and a hydrodesulfurization zone was
controlled to 380°C, and the temperature of a hydrocracking zone was controlled to
400°C.
[0050] [Table 5]
Table 5-1
|
Example |
1 |
2 |
3 |
4 |
5 |
Feedstock |
Heavy oil |
A |
A |
A |
A |
A |
Mixing oil |
A |
B |
B |
B |
C |
Reaction conditions |
Catalyst |
A 25 mL |
A 25 mL |
A 25 mL |
A 25 mL |
A 25 mL |
B 75 mL |
B 75 mL |
B 75 mL |
B 75 mL |
B 75 mL |
Reaction temp. (°C) (hydrocracking zone) |
380 |
380 |
380 |
380 |
380 |
Partial H2 pressure (MPaG) |
13.2 |
13.2 |
13.2 |
13.2 |
13.2 |
H2/oil (Nm3/kL) |
800 |
800 |
800 |
800 |
800 |
Total LHSV for feedstock (hr-1) |
0.315 |
0.287 |
0.364 |
0.519 |
0.296 |
343°C+ Fraction content in feedstock (vol.%) |
66.2 |
72.6 |
57.3 |
47.9 |
70.4 |
LHSV for 343°C+ fraction (hr-1) |
0.209 |
0.209 |
0.209 |
0.209 |
0.209 |
Table 5-2
|
Example |
6 |
7 |
8 |
9 |
10 |
Feedstockl |
Heavy oil |
A |
A |
C |
B |
A |
Mixing oil |
D |
E |
B |
B |
B |
Reaction conditions |
Catalyst |
|
|
|
|
A 25 mL |
A 25 mL |
A 25 mL |
A 25 mL |
A 25 mL |
C 33 mL |
B 75 mL |
B 75 mL |
B 75 mL |
B 75 mL |
B 42 mL |
Reaction temp. (°C) (hydrocracking zone) |
380 |
380 |
380 |
380 |
380 (400) |
Partial H2 Pressure (MPaG) |
13.2 |
13.2 |
13.2 |
13.2 |
13.2 |
H2/oil (Nm3/kL) |
800 |
800 |
800 |
800 |
800 |
Total LHSV for feedstock (hr-1) |
0.297 |
0.305 |
0.315 |
0.287 |
0.287 |
343°C+ Fraction content in feedstock (vol.%) |
70.2 |
68.4 |
66.2 |
72.6 |
72.6 |
LHSV for 343°C+ fraction (hr-1) |
0.209 |
0.209 |
0.209 |
0.209 |
0.209 |
Table 5-3
|
Example |
1 |
2 |
3 |
4 |
5 |
Evaluation of refined oil (343°C+ fraction) |
Conversion (volume basis %) |
16.5 |
16.4 |
18.2 |
20.4 |
16.4 |
S content (wt.%) |
0.38 |
0.40 |
0.35 |
0.30 |
0.41 |
Metal content (V+Ni) (wt.ppm) |
30.6 |
31.6 |
27.3 |
23.1 |
32.0 |
Desulfurization conversion (wt.%) |
91.3 |
91.0 |
92.1 |
93.3 |
90.8 |
Desulfurization rate constant (second order) (hr-1) |
49.6 |
47.8 |
55.1 |
65.8 |
46.7 |
Calculated by Pro/II |
Hydrogen content of liquid phase (reactior inlet) (wt.%) |
0.108 |
0.113 |
0.130 |
0.157 |
0.114 |
Hydrogen content of liquid phase (reactior outlet) (wt.%) |
0.186 |
0.172 |
0.195 |
0.229 |
0.167 |
Hydrogen content (av., inlet and outlet) (wt.%) |
0.147 |
0.143 |
0.163 |
0.193 |
0.140 |
Table 5-4
|
Example |
6 |
7 |
8 |
9 |
10 |
Evaluation of refined oil (343°C+ fraction) |
Conversion (volume basis %) |
16.5 |
16.5 |
6.8 |
16.5 |
46.5 |
S content (wt.%) |
0.40 |
0.40 |
1.00 |
0.19 |
0.91 |
Metal content (V+Ni) (wt.ppm) |
31.9 |
31.9 |
36.0 |
0.1> |
26.2 |
Desulfurization conversion (wt.%) |
90.9 |
90.9 |
81.9 |
93.5 |
79.4 |
Desulfurization rate constant (second order) (hr-1) |
47.2 |
47.2 |
17.1 |
101.5 |
18.2 |
Calculated by Pro/II |
Hydrogen content of liquid phase (reactior inlet) (wt.%) |
0.115 |
0.113 |
0.087 |
0.175 |
0.113 |
Hydrogen content of liquid phase (reactior outlet) (wt.%) |
0.166 |
0.168 |
0.175 |
0.187 |
0.172 |
Hydrogen content (av., inlet and outlet) (wt.%) |
0.141 |
0.141 |
0.131 |
0.181 |
0.143 |
[0051] [Table 6]
Table 6-1
|
Comparative Example |
1 |
2 |
3 |
4 |
5 |
Feedstockl |
Heavy oil |
A |
A |
C |
B |
A |
Mixing oil |
- |
F |
- |
- |
- |
Reaction conditions |
Catalyst |
|
|
|
|
A 25 mL |
A 25 mL |
A 25 mL |
A 25 mL |
A 25 mL |
C 33 mL |
B 75 mL |
B 75 mL |
B 75 mL |
B 75 mL |
B 42 mL |
Reaction temp. (°C) (hydrocracking zone) |
380 |
380 |
380 |
380 |
380 (400) |
Partial H2 pressure (MPaG) |
13.2 |
13.2 |
13.2 |
13.2 |
13.2 |
H2/oil (Nm3/kL) |
800 |
800 |
800 |
800 |
800 |
Total LHSV for feedstock (hr-1) |
0.210 |
0.315 |
0.209 |
0.209 |
0.210 |
343°C+ Fraction content in feedstock (vol.%) |
99.3 |
66.2 |
100.0 |
100.0 |
99.3 |
LHSV for 343°C+ fraction (hr-1) |
0.209 |
0.209 |
0.209 |
0.209 |
0.209 |
Table 6-2
|
Comparative Example |
1 |
2 |
3 |
4 |
5 |
Evaluation of refined oil (343°C+ fraction) |
Conversion (volume basis %) |
14.4 |
14.0 |
3.8 |
15.0 |
42.1 |
S content (wt.%) |
0.48 |
0.50 |
1.82 |
0.22 |
1.08 |
Metal content (V+Ni) (wt.ppm) |
38.1 |
39.0 |
75.0 |
0.1> |
32.0 |
Desulfurization conversion (wt.%) |
89.1 |
88.7 |
67.1 |
92.5 |
75.5 |
Desulfurization rate constant (second order) (hr-1) |
38.6 |
37.1 |
7.7 |
87.7 |
14.6 |
Calculated by Pro/II |
Hydrogen content of liquid phase (reactior inlet) |
0.090 |
0.087 |
0.060 |
0.152 |
0.090 |
Hydrogen content of liquid phase (reactior outlet) (wt.%) |
0.142 |
0.138 |
0.061 |
0.164 |
0.143 |
Hydrogen content (av., inlet and outlet) (wt.%) |
0.116 |
0.113 |
0.061 |
0.158 |
0.117 |
[0052] "LHSV for 343°C+ fraction" shown in Tables 5 and 6 is obtained by multiplying the
total LHSV for feedstock employed in the experiment by the volume-basis amount of
a fraction having a boiling point of 343°C or higher (i.e., a 343°C+ fraction) contained
in the feedstock. Therefore, "LHSV for 343°C+ fraction" corresponds to the substantial
LHSV for 343°C+ fraction fed into the reactor. The present invention is not intended
to enhance hydrorefining performance by the dilution effect, but intended to enhance
performance in hydrorefining of a heavy oil fraction by the aforementioned dissolved
hydrogen concentration increasing effect. Therefore, hydrorefining performance was
evaluated by focusing on, for example, the sulfur content of the 343°C+ fraction of
the refined oil. Desulfurization conversion for the 343°C+ fraction was determined
by use of the following calculation formula.

[0053] Under the assumption that the desulfurization reaction is a second-order reaction,
apparent reaction rate constant was determined by use of the following formula.

[0054] The composition of a gas phase or a liquid phase at the inlet or outlet of the reactor
was estimated by means of a process simulator Pro/II (ver. 6.01) (product of Invensys
Process Systems) as described above.
The estimation data are shown in Tables 5 and 6.
[0055] [Table 7]
Table 7-1
|
Example |
1 |
2 |
3 |
4 |
5 |
Hydrogen content of liquid phase in reactor (av., inlet and outlet) |
0.147 |
0.143 |
0.163 |
0.193 |
0.140 |
Desulfurization rate constant (second order) |
49.6 |
47.8 |
55.1 |
65.8 |
46.7 |
Total LHSV for feedstock (hr-1) |
0.315 |
0.287 |
0.364 |
0.519 |
0.296 |
Corresponding Comp. Ex. |
1 |
1 |
1 |
1 |
1 |
Relative hydrogen content of liquid phase in reactor (Ex./Comp. Ex.) |
1.28 |
1.23 |
1.41 |
1.66 |
1.21 |
Relative reaction rate constant (Ex./Comp. Ex.) |
1.28 |
1.25 |
1.43 |
1.70 |
1.21 |
Relative LHSV (Ex./Comp. Ex.) |
1.50 |
1.37 |
1.73 |
2.47 |
1.41 |
Table 7-2
|
Example |
6 |
7 |
8 |
9 |
10 |
Hydrogen content of liquid phase in reactor (av., inlet and outlet) |
0.141 |
0.141 |
0.131 |
0.181 |
0.143 |
Desulfurization rate constant (second order) |
47.2 |
47.2 |
17.1 |
101.5 |
18.2 |
Total LHSV for feedstock (hr-1) |
0.297 |
0.305 |
0.315 |
0.287 |
0.287 |
Corresponding Comp. Ex. |
1 |
1 |
3 |
4 |
5 |
Relative hydrogen content of liquid phase in reactor (Ex./Comp. Ex.) |
1.22 |
1.22 |
2.15 |
1.15 |
1.22 |
Relative reaction rate constant (Ex./Comp. Ex.) |
1.22 |
1.22 |
2.23 |
1.15 |
1.25 |
Relative LHSV (Ex./Comp. Ex.) |
1.41 |
1.45 |
1.51 |
1.37 |
1.37 |
Table 7-3
|
Comparative Example |
1 |
2 |
3 |
4 |
5 |
Hydrogen content of liquid phase in reactor (av., inlet and outlet) |
0.116 |
0.113 |
0.061 |
0.158 |
0.117 |
Desulfurization rate constant (second order) |
38.6 |
37.1 |
7.7 |
87.7 |
14.6 |
Total LHSV for feedstock (hr-1) |
0.210 |
0.315 |
0.209 |
0.209 |
0.210 |
Corresponding Comp. Ex. |
- |
1 |
- |
- |
- |
Relative hydrogen content of liquid phase in reactor (Ex./Comp. Ex.) |
- |
0.97 |
- |
- |
- |
Relative reaction rate constant (Ex./Comp. Ex.) |
- |
0.96 |
- |
- |
- |
Relative LHSV (Ex./Comp. Ex.) |
- |
1.50 |
- |
- |
- |
[0056] The results of the Examples and Comparative Examples are collectively shown in Table
7.
In Example 1, the hydrogen content of the liquid phase in the reactor is higher by
28%, as compared with the case of Comparative Example 1. In Example 1, the reaction
rate of the 343°C+ fraction is higher, as compared with the case of Comparative Example
1, although the actual LHSV for feedstock is 1.5 times that in Comparative Example
1 (i.e., in Example 1, the reaction is carried out under more disadvantageous conditions).
Therefore, in Example 1, more effective hydrorefining is achieved. Comparison between
data of Example 1 and Comparative Example 1 shows that the hydrogen content of the
liquid phase in the reactor is correlated with the reaction rate of the 343°C+ fraction.
A tendency similar to that in Example 1 is also observed in Examples 2 to 10.
In contrast, in Comparative Example 2, in which straight-run n-butane having no effect
of increasing dissolved hydrogen concentration is employed, effective hydrorefining
is not achieved.
Industrial Applicability
[0057] According to the present invention, there is provided a hydrocarbon oil hydrorefining
method which, in hydrorefining of a hydrocarbon oil containing heavy oil, can enhance
performance in hydrorefining of the heavy oil, to thereby produce an increased amount
of a refined oil, to produce a high-quality refined oil, and to attain mild hydrorefining
conditions. According to the hydrorefining method, energy savings can be achieved
in the overall process of crude oil refining.
1. A hydrocarbon oil hydrorefining method, characterized by comprising providing a mixture of a heavy hydrocarbon oil and a dissolved-hydrogen-concentration-increasing
hydrocarbon oil; mixing the oil mixture, which is subjected to hydrorefining, with
hydrogen; and causing the resultant mixture to pass through a reactor for carrying
out hydrorefining.
2. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the oil mixture
of a heavy hydrocarbon oil and a dissolved-hydrogen-concentration-increasing hydrocarbon
oil has a dissolved hydrogen concentration which is 1.1 times or more the highest
possible hydrogen concentration of the heavy hydrocarbon oil.
3. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the heavy
hydrocarbon oil is one or more species selected from among vacuum residual oil, vacuum
gas oil, atmospheric residual oil, topped crude oil, crude oil, deasphalted oil, coal-liquefied
oil, oil obtained from oil sand, and oil obtained from oil shale.
4. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the dissolved-hydrogen-concentration-increasing
hydrocarbon oil is contained in a liquid phase entirely or partially under the conditions
in the reactor.
5. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the effect
of increasing dissolved hydrogen concentration is estimated on the basis of the equilibrium
of hydrogen between gas and liquid in the reactor.
6. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the dissolved-hydrogen-concentration-increasing
hydrocarbon oil is additionally fed, as a quenching oil, into the reactor.
7. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the dissolved-hydrogen-concentration-increasing
hydrocarbon oil is one or more species selected from among a straight-run kerosene
fraction, a straight-run light gas oil fraction, a straight-run heavy gas oil fraction,
cracked oil obtained from an FCC unit, and thermally cracked oil obtained from a coker
unit.
8. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the hydrorefining
includes one or more steps selected from among a hydrodemetallization step, a hydrodesulfurization
step, a hydrocracking step, a hydrodenitrogenation step, and a hydrodearomatization
step;
9. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the hydrorefining
is carried out under the following conditions: a reaction temperature of 300 to 450°C,
a hydrogen partial pressure of 5.1 to 25.3 MPa(G), a hydrogen/oil ratio of 200 to
2,000 Nm3/kL, and an LHSV of 0.05 to 10 hr-1.
10. A hydrocarbon oil hydrorefining method as described in claim 1, wherein the hydrorefining
is carried out under the following conditions: a reaction temperature of 330 to 430°C,
a hydrogen partial pressure of 10.1 to 20.3 MPa(G), a hydrogen/oil ratio of 500 to
1,000 Nm3/kL, and an LHSV: 0.1 to 1.0 hr-1.