DESCRIPTION
Title of Invention
PROCESS FOR PRODUCING REGENERATED HYDROTREATING
CATALYST AND PROCESS FOR PRODUCING PETROCHEMICAL
PRODUCT
Technical Field
[0001] The present invention relates to a process for producing a
regenerated hydrotreating catalyst for treating a distillate petroleum
jfraction and a process for producing a petroleum product made from a
distillate petroleum fraction.
Background Art
[0002] Sulfiir-containing compounds, nitrogen-containing compounds,
oxygen-containing compounds, and the like are contained in crude
petroleum as impurities and these impurities are also contained in
distillate petroleum fractions obtained by distilling the crude petroleum.
The impurities in these distillate petroleum fractions are reduced in their
contents by a step of bringing the fractions into contact with a catalyst
having a hydrogenation activity in the presence of hydrogen, the step
being referred to as hydrotreatment. Especially, desulfiirization for
reducing contents of the sulfur-containing compounds is well known.
Recently, from the viewpoint of reducing environmental load, there has
been stricter demand for controlling or reducing contents of the
impurities including the sulfijr-containing compounds in petroleum
products, and a large number of petroleum products referred to as
so-called "sulfiir free" are manufactured.
[0003] After a hydrotreating catalyst used for hydrotreatment of the
1
distillate petroleum fraction is used for a certain period of time, its
activity lowers due to deposition of coke or sulfur components, and the
like, and therefore, replacement is carried out. Especially, the "sulfur
free" is required, and a greater hydrotreating capability is required in
hydrotreating facilities for fractions such as kerosene, gas oil, and
vacuum gas oil. As a result, frequency of the replacement of the
catalyst is increased, which leads to an increase in catalyst cost and an
increase in an amount of waste catalyst.
[0004] To combat this, a regenerated catalyst (regenerated hydrotreating
catalyst) regenerated from a spent hydrotreating catalyst is partially
used in these facilities (For example, see Patent Literatures 1 and 2.).
Citation List
Patent Literature
[0005] Patent Literature 1: Japanese Patent Application Laid-Open
Publication No. 52-68890
Patent Literature 2: Japanese Patent Application Laid-Open Publication
No. 05-123586
Summary of Invention
Technical Problem
[0006] In the use of the regenerated catalyst, if it is possible to maintain
the activity of the hydrotreating catalyst even after hydrotreatment and
regeneration are repeated multiple times, advantages of using the
hydrotreating catalyst regenerated (hereinafter, referred to as
"regenerated hydrotreating catalyst" or just as "regenerated catalyst")
become greater. In conventional regeneration, it is possible to restore
the activity by regeneration in viewpoint of the deposition of coke or
2
sulflir which is the main cause of a decrease in the activity occurred in
the use of the hydrotreating catalyst. However, the catalyst activity
may be lowered because the regeneration itself changes a structure of an
active metal supported on the catalyst or something like that. In
addition, as the catalyst activity after regeneration varies depending on
the usage history before regeneration of the catalyst, a method of
regeneration, or the like, the regenerated catalyst, especially the
regenerated catalyst after regenerated multiple times does not always
have a sufficient activity steadily. Moreover, it may be necessary to
select conditions of regeneration depending on the usage history of the
spent catalyst or the like. Furthermore, when the activity is found to
be low after packing the regenerated catalyst in the hydrotreating
facilities and starting hydrotreating operation, there is a need for
reduction of a treatment speed of a feed oil or the like, which presents a
major problem.
[0007] For the reasons mentioned above, a real situation is that the
regenerated catalyst is not necessarily employed in the hydrotreating
facilities sufficiently. Therefore, it is strongly demanded that a
decrease in the activity by regeneration of the hydrotreating catalyst be
inhibited and a regenerated catalyst having a high activity steadily be
provided,
[0008] The present invention has been made in view of the
aforementioned circumstances, and an object of the present invention is
to provide a process for producing a regenerated hydrotreating catalyst
enabling production of a regenerated hydrotreating catalyst having a
high activity steadily from a spent hydrotreating catalyst. Another
3
object of the present invention is to provide an economically efficient
process for producing a petroleum product by using the regenerated
hydrotreating catalyst.
Solution to Problem
[0009] Aiming at solving the above problems, the present invention
provides a process for producing a regenerated hydrotreating catalyst by
regenerating a spent hydrotreating catalyst in a prescribed temperature
range, wherein the prescribed temperature range is a temperature range
of Ti - 30°C or more and T2 + 30°C or less, as determined by subjecting
the spent hydrotreating catalyst to a differential thermal analysis,
converting a differential heat in a measuring temperature range of
100°C or more and 600°C or less to a difference in electromotive force,
differentiating the converted value twice by temperature to provide a
smallest extreme value and a second smallest extreme value, and
representing a temperature corresponding to the extreme value on the
lower-temperature side as Ti and a temperature corresponding to the
extreme value on the higher-temperature side as T2.
[0010] Here, "differential thermal analysis" is an analysis method of
elevating a temperature of a sample under prescribed temperature
conditions and measuring variations in the amount of heat
accompanying gasification, oxidation, thermal decomposition, and the
like. Specifically, for example, measurement is performed by
measuring out about 5 mg of a sample into a platinum pan having an
internal diameter of 5 mm, setting it in a differential thermal analyzer,
and elevating a temperature of the sample fi-om room temperature to
700°C at 10°C/minute and a flow rate of air of 100 ml/minute.
4
[0011] Hereinafter, a description will be given of a calculation method
of Ti and T2 based on Figures 1 to 5.
Figure 1 is a chart representing a temperature range of 100°C or more
and 600°C or less of results of a differential thermal analysis on a
sample.
In this chart, two peaks (peak 1 and peak 2) are apparently observed;
however, it is necessary to carry out the following processing in order to
exactly obtain a temperature corresponding to an extreme value of the
peak.
[0012] On the chart shown in Figure 1, a value (AV/AT) obtained by
dividing a difference (AV) by a difference (AT), the difference (AT)
being a difference between a measurement temperature and the next
measurement temperature after elevating a temperature (for example, a
temperature elevated by 0.1 °C) and the difference (AV) being a
difference between values obtained by converting differential heats at
the measurement temperatures to differences in electromotive force, is
calculated, and this calculation is repeated from 100°C to 600°C, which
provides a chart shown in Figure 2.
[0013] Next, Figure 3 is provided by averaging out values in a
measurement temperature range including a temperature and ranging
from the temperature - 10°C to the temperature + 10°C, and a value of
the ordinate in the chart is referred to as "a value obtained by converting
a differential heat to a difference in electromotive force and
differentiating the converted value by temperature".
[0014] Furthermore, Figures 4 and 5 are provided by performing the
same processing as that mentioned above on the chart shown in Figure
5
3. Here, a value of the ordinate in the chart shown in Figure 5 is
referred to as "a value obtained by converting a differential heat to a
difference in electromotive force and differentiating the converted value
twice by temperature". Of a smallest extreme value and a second
smallest extreme value in this chart, a temperature corresponding to the
extreme value on the lower-temperature side is represented as Ti and a
temperature corresponding to the extreme value on the
higher-temperature side is represented as T2.
[0015] Ti and T2 correspond to the peak 1 and the peak 2 in Figure 1,
respectively. In addition, Ti is a benchmark of a temperature where a
sulfide of an active metal such as molybdenum in the spent catalyst
bums to turn into an oxide of the active metal and T2 is a benchmark of
a temperature where coke depositing on the spent catalyst bums.
[0016] In the process for producing a regenerated hydrotreating catalyst
of the present invention, it is preferred that a residual carbon content in
the regenerated hydrotreating catalyst be 0.2% by mass or more and
3.0% by mass or less.
[0017] In addition, in the process for producing a regenerated
hydrotreating catalyst of the present invention, it is preferred that the
hydrotreating catalyst be a catalyst obtained by supporting 10 to 30% by
mass of at least one selected from Group 6 metals of the periodic table
and 1 to 7% by mass of at least one selected from Group 8 to 10 metals
of the periodic table, based on a total mass of the catalyst, on an
inorganic support comprising an oxide of aluminum.
[0018] Moreover, in the process for producing a regenerated
hydrotreating catalyst of the present invention, it is preferred that the at
6
least one selected from Group 6 metals of the periodic table be
molybdenum, and the at least one selected from Group 8 to 10 metals of
the periodic table be cobalt and/or nickel.
[0019] Furthermore, in the process for producing a regenerated
hydrotreating catalyst of the present invention, it is preferred that the
spent hydrotreating catalyst be regenerated under an air flow having a
flow rate per unit volume of the catalyst of from 20 to 2000
NL/h-L-catalyst for 2 hours or more. In the units, "NL" means a flow
rate of air in a standard condition, "h" means hour, and "L-catalyst"
means a volume of the catalyst.
[0020] The present invention provides a process for producing a
petroleum product, comprising: a first step of producing a regenerated
hydrotreating catalyst by the process for producing a regenerated
hydrotreating catalyst of the present invention; and a second step of
hydrotreating a distillate petroleum fraction by using the regenerated
hydrotreating catalyst obtained in the first step.
[0021] In the process for producing a petroleum product of the present
invention, it is preferred that operating conditions of the second step be
a hydrogen partial pressure of from 3 to 13 MPa, a LHSV of from 0.05
to 5 h"\ a reaction temperature of from 200°C to 410°C, a ratio of
hydrogen/oil of from 100 to 8000 SCF/BBL, and distillation properties
of a feed oil of 150°C or more and 600°C or less.
[0022] The present invention also provides a regenerated hydrotreating
catalyst produced by the process for producing a regenerated
hydrotreating catalyst of the present invention.
Advantageous Effects of Invention
7
[0023] The process for producing a regenerated hydrotreating catalyst
of the present invention has an advantage of being capable of easily
producing a regenerated hydrotreating catalyst having a sufficient
activity. In addition, the process for producing a petroleum product of
the present invention can achieve a highly practical producing process
using a regenerated hydrotreating catalyst having a sufficient activity
with a lower price and is remarkably useful in terms of reduction of
cost, reduction of an emission amount of waste product, efficiency in
hydrotreatment of a distillate petroleum fraction, production of a
petroleum product with higher quality, and so on.
Brief Description of Drawings
[0024] [Figure 1] Figure 1 is a view for explaining a calculation method
ofTi andT2.
[Figure 2] Figure 2 is a view for explaining a calculation method of Ti
andT2.
[Figure 3] Figure 3 is a view for explaining a calculation method of Ti
and T2.
[Figure 4] Figure 4 is a view for explaining a calculation method of Ti
andT2.
[Figure 5] Figure 5 is a view for explaining a calculation method of Ti
andT2.
Description of Embodiments
[0025] Hereinafter, a detailed description will be given of preferred
embodiments of the present invention,
[0026] (Hydrotreating catalyst)
A hydrotreating catalyst used in the present invention preferably
8
comprises at least one of Group 6 metals of the periodic table and at
least one of Group 8 to 10 metals as active metals. Examples of the
Group 6 metals of the periodic table preferably include molybdenum,
tungsten, and chrome, more preferably include molybdenum and
tungsten, and especially preferably include molybdenum. Examples of
the Group 8 to 10 metals of the periodic table preferably include iron,
cobalt, and nickel, more preferably include cobalt and nickel, and
especially preferably include cobalt. These metals can be used alone
or in combination of two or more. Preferred examples of a specific
combination of the metals to be used include molybdenum-cobalt,
molybdenum-nickel, tungsten-nickel, molybdenum-cobalt-nickel, and
tungsten-cobalt-nickel. The periodic table herein means a long form
periodic table provided by International Union of Pure and Applied
Chemistry (lUPAC).
[0027] The hydrotreating catalyst according to the present invention is
preferably a catalyst in which the metals are supported on an inorganic
support comprising an oxide of aluminum. Preferred examples of the
inorganic support comprising an oxide of aluminum include alumina,
alumina-silica, alumina-boria, alumina-titania, alumina-zirconia,
alumina-magnesia, alumina-silica-zirconia, alumina-silica-titania, or a
support in which a porous inorganic compound such as various clay
minerals including various zeolites, sepiolite, and montmorillonite is
added to alumina, and of these, alumina is especially preferred.
[0028] The hydrotreating catalyst according to the present invention is
preferably a catalyst obtained by supporting 10 to 30% by mass of the at
least one selected from Group 6 metals of the periodic table and 1 to 7%
9
by mass of the at least one selected from Group 8 to 10 metals of the
periodic table, based on a total mass of the catalyst, on the inorganic
support comprising an oxide of aluminum. When supported amounts
of the Group 6 metals of the periodic table and the Group 8 to 10 metals
of the periodic table are less than their own lower limits, the catalyst
tends not to exert a sufficient hydrotreating activity, and on the other
hand, when the supported amounts exceed their own upper limits,
catalyst cost increases, and the catalyst tends not to exert a sufficient
hydrotreating activity because agglomeration of the supported metal is
likely to occur.
[0029] Examples of a precursor of the metal species used in supporting
the metal on the inorganic support include, but are not limited to,
inorganic salts of the metals and organic metal compounds, and
preferably include water-soluble inorganic salts. In a supporting step,
it is preferred to carry out supporting by using a solution, preferably an
aqueous solution, of the precursor of the metal. As supporting
operation, for example, a known method such as an immersion method,
an impregnation method, and a coprecipitation method is preferably
employed.
[0030] It is preferred that the support on which the precursor of the
metal is supported be calcined preferably in the presence of oxygen
after dried to once convert the metal species to an oxide. Furthermore,
before hydrotreating a distillate petroleum fraction, it is preferred to
convert the metal species to a sulfide by a sulfiding process referred to
as "pre-sulfiding".
[0031] (Regeneration step)
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The hydrotreating catalyst which has been used at a
hydrotreating facility for a distillate petroleum fraction for a certain
period of time and then represents the activity lower than a certain level
is subjected to regeneration. A preferred example of a facility for
carrying out the regeneration includes, but is not especially limited to, a
facility different from the hydrotreating facility for a distillate petroleum
fraction. Specifically, the regeneration is not carried out with keeping
the catalyst packed into a reactor of the hydrotreating facility for a
distillate petroleum fraction; it is preferred to pull out the catalyst from
the reactor, move the pulled-out catalyst to a facility for regeneration,
and carry out the regeneration at the facility.
[0032] A procedure for carrying out the regeneration of the spent
catalyst used in the present invention, but is not limited, preferably
comprises, in the following order, a step of removing, by sieving, a
pulverized catalyst from the spent catalyst, and optionally components
other than the catalyst, such as a filler, a step of removing oil attached to
the spent catalyst (deoiling step), and a step of removing coke, sulfiir
components, and the like depositing on the spent catalyst (regeneration
step).
[0033] Of these, as the deoilmg step, a method of volatilizing the oil
components by heating the spent catalyst in an atmosphere where
oxygen is not substantially present, for example, in a nitrogen
atmosphere, or the like is preferably employed. The conditions
preferably include, for example, heating at a temperature of from about
300°C to 400°C and a flow rate of nitrogen in terms of a flow rate per
unit volume of the catalyst of from 5 to 150 NL/h-L-catalyst for 3 to 7
11
hours. Alternatively, the deoiling step may be conducted by a method
of cleaning the oil components by light hydrocarbons, a method of
removing the oil components by steaming, or the like.
[0034] When the regeneration is carried out in an air flow, a flow rate of
air in terms of a flow rate per unit volume of the spent catalyst is
preferably from 20 to 2000 NL/h-L-catalyst, more preferably from 30 to
1000 NL/h-L-catalyst, and especially preferably from 40 to 500
NL/h-L-catalyst. When the flow rate is less than 20 NL/h-L-catalyst,
there is a tendency that coke, sulfur components, or the like depositing
on the spent catalyst is not removed sufficiently and the activity of a
regenerated catalyst is not improved sufficiently. On the other hand,
when the flow rate exceeds 2000 NL/h-L-catalyst, there is a need to
increase a size of a compressor, which impairs economic efficiency.
[0035] In the regeneration step, the regeneration is carried out at a
temperature of Ti - 30°C or more and T2 + 30°C or less. The lower
limit of the temperature of the regeneration is Ti - 30°C or more,
preferably Ti - 20°C or more, and especially preferably Ti - 10°C or
more in order to convert the active metal having a sulfide state in the
spent catalyst back to an oxide state. On the other hand, the lower
limit of the temperature of the regeneration is T2 + 30°C or less,
preferably T2 + 20°C or less, and especially preferably T2 + 10°C or less
because the activity of the regenerated catalyst decreases if coke
depositing on the catalyst is burned and removed completely.
[0036] The time of the regeneration is preferably 2 hours or more, more
preferably 2.5 hours or more, and especially preferably 3 hours or more.
When the treatment time is less than 2 hours, removal of substances
12
which have reduced the catalyst activity, such as coke and sulfur
components, tends not to proceed efficiently. It is noted that "coke" in
the present application means a substance in which a hydrocarbon
depositing on a surface of the hydrotreating catalyst in the use of the
hydrotreating catalyst is highly cyclized and condensed and which is
similar in appearance to carbon.
[0037] The regenerated hydrotreating catalyst obtained in the
regeneration step contains residual carbon at a content with a lower
limit preferably of 0.2% by mass or more, more preferably of 0.4% by
mass or more, and especially preferably of 0.5% by mass or more, and
with an upper limit preferably of 3.0% by mass or less, more preferably
of 2.5% by mass or less, and especially preferably of 2.0% by mass or
less based on a mass of the regenerated hydrotreating catalyst. When
the residual carbon content is less than 0.2% by mass or exceeds 3.0%
by mass, the hydrotreating activity of the regenerated catalyst tends to
be not high enough. It is noted that "residual carbon" in the present
application means carbon (coke) remaining in the regenerated catalyst
after regenerating the spent hydrotreating catalyst, and the residual
carbon content in the regenerated hydrotreating catalyst is measured in
accordance with "Coal and coke - Mechanical methods for ultimate
analysis" defined in JIS M 8819.
[0038] It is noted that a step of producing a regenerated hydrotreating
catalyst in the process for producing a petroleum product of the present
invention is a step of producing a regenerated hydrotreating catalyst by
the process for producing a regenerated hydrotreating catalyst of the
present invention, and includes the aforementioned steps. Aspects of a
13
hydrotreating catalyst and a regeneration step in the process for
producing a petroleum product of the present invention are the same as
those mentioned above, and the overlapping explanation will be omitted
here.
[0039] (Hydrotreatment step)
In a hydrotreatment step of a distillate petroleum fraction of the
present invention, it is preferred to convert the active metal species into
a metal sulfide by subjecting the regenerated catalyst packed in the
facility to a treatment of the catalyst using a sulfur compound referred to
as pre-sulfiding before a hydrotreatment reaction.
[0040] There is no particular restriction on conditions of the
pre-sulfiding, but it is preferred to add a sulfur compound to a feed oil
used for the hydrotreatment of a distillate petroleum fraction and bring
it into contact with the regenerated catalyst continuously under
conditions of a temperature of from 200 to 380°C, a LHSV of from 1 to
2 h"^, a pressure same as that in operation of the hydrotreatment, and a
treatment time of 48 hours or more. Examples of the sulfur compound
added to the feed oil preferably include, but are not limited to, dimethyl
disulfide (DMDS) and hydrogen sulfide, and it is preferred to add about
1% by mass of these compounds to the feed oil based on a mass of the
feed oil.
[0041] Operating conditions in the aforementioned hydrotreatment step
of a distillate petroleum fraction are not especially limited, but it is
preferred not to add a sulfur compound in particular because it is
generally possible to keep the active metal species of the catalyst in the
sulfide state by the sulfur compound already contained in the feed oil,
14
while a small amount of a sulfur compound such as DMDS may be
added to the feed oil in order to keep the active metal species of the
catalyst in the sulfide state.
[0042] A hydrogen partial pressure at an inlet of a reactor in the
hydrotreatment step is preferably from 3 to 13 MPa, more preferably
from 3.5 to 12 MPa, and especially preferably from 4 to 11 MPa.
When the hydrogen partial pressure is less than 3 MPa, there is a
tendency that generation of coke on the catalyst becomes intense and a
life-span of the catalyst becomes shortened. On the other hand, when
the hydrogen partial pressure exceeds 13 MPa, there is a fear that
construction cost of the reactor, surrounding equipment, and the like
increases and economical efficiency is impaired.
[0043] A LHSV in the hydrotreatment step can range preferably from
0.05 to 5 h'\ more preferably from 0.1 to 4.5 h'\ and especially
preferably from 0.2 to 4 h'\ When the LHSV is less than 0.05 Kthere is a fear that the construction cost of the reactor becomes
excessive and the economical efficiency is impaired. On the other
hand, when the LHSV exceeds 5 h'\ there is a fear that the
hydrotreatment of the feed oil is not achieved sufficiently.
[0044] A temperature of a hydrogenation reaction in the hydrotreatment
step is preferably from 200°C to 410°C, more preferably from 220°C to
400°C, and especially preferably from 250°C to 395°C. When the
reaction temperature is less than 200°C, the hydrotreatment of the feed
oil tends not to be achieved sufficiently. On the other hand, the case
where the reaction temperature exceeds 410°C is undesirable because, if
so, generation of a gas component which is a by-product increases, and
15
therefore, yield of an objective refined oil decreases.
[0045] A ratio of hydrogen/oil in the hydrotreatment step is preferably
fi-om 100 to 8000 SCF/BBL, more preferably from 120 to 7000
SCF/BBL, and especially preferably fi-om 150 to 6000 SCF/BBL.
When the ratio of hydrogen/oil is less than 100 SCF/BBL, there is a
tendency that generation of coke on the catalyst at an outlet of the
reactor progresses and the life-span of the catalyst becomes shortened.
On the other hand, when the ratio of hydrogen/oil exceeds 8000
SCF/BBL, there is a fear that construction cost of a recycle compressor
becomes excessive and the economical efficiency is impaired.
[0046] A reaction style in the hydrotreatment step is not especially
limited, but can be generally selected fi*om various processes such as
fixed bed and moving bed, and the fixed bed is preferred. In addition,
the reactor is preferred to be tower shaped.
[0047] As the feed oil subjected to the hydrotreatment of a distillate
petroleum fi"action of the present invention, a feed oil having a
distillation temperature by a distillation test preferably of fi*om 130 to
600°C, more preferably of fi-om 140 to 550°C, and especially preferably
of fi-om 150 to 500°C is used. When a feed oil having a distillation
temperature of less than 130°C is used, there is a tendency that the
hydrotreatment reaction becomes a gas-phase reaction and the
aforementioned catalyst does not exert its performance sufficiently.
On the other hand, when a feed oil having a distillation temperature of
more than 600°C is used, a content of a poisoning substance to the
catalyst such as a heavy metal contained in the feed oil becomes larger
and the life-span of the catalyst decreases remarkably. There is no
16
particular restriction on other properties of the distillate petroleum
fraction used as the feed oil, but typical properties are that a density at
15°C is from 760.0 to 970.0 kg/m and a sulfiir component content is
from 0.02 to 4.0% by mass.
[0048] It is noted that the sulfiir content in the present invention means
a sulfiar content measured in accordance with "6. Energy-dispersive
X-ray fluorescence method" in "Crude oil and petroleum products -
Determination of sulfiir content" defined in JIS K 2541-1992. In
addition, the distillation test in the present application means a test
performed in accordance with "6. Determination of vacuum distillation
characteristics" in "Petroleum products - Determination of distillation
characteristics" defmed in JIS K 2254. Moreover, the density of a
distillate petroleum fraction in the present application means a density
measured in accordance with "5. Oscillating density test method" in
"Crude petroleum and petroleum products - Determination of
density-and petroleum measurement tables based on a reference
temperature (15 centigrade degrees) (excerpt)" defmed in JIS K 2249.
[0049] Furthermore, an example of means of directly evaluating the
hydrotreating activity of the regenerated catalyst includes a
desulfijrization rate constant under an identical operating condition.
The desulfiorization rate constant is defined by the following formula.
Desulfurization rate constant = LHSV x (1/sulfiir content in product oil
- 1/sulfiar content in feed oil)
[0050] It is noted that the activity of a new catalyst varies with its
manufacturer, its production unit, and the like, and therefore, it is
considered valid to evaluate the activity of the regenerated catalyst
17
obtained by regenerating a hydrotreating catalyst after using the
hydrotreating catalyst by relative activity based on the activity of a
corresponding new catalyst. Then, the activity of the regenerated
catalyst is evaluated by specific activity defined by the following
formula.
Specific activity = desulftirization rate constant of regenerated
catalyst/desulfurization rate constant of new catalyst
Examples
[0051] Next, a further detailed description will be given of the present
invention with reference to Examples and Comparative Examples, but it
should be construed that the invention is in no way limited to those
examples.
[0052] [Example 1] (Regenerated hydrotreating catalyst)
A spent hydrotreating catalyst 1 which was a catalyst containing
molybdenum and cobalt as active metals supported on an alumina
support and was pulled out after having been used in a hydrotreating
facility for kerosene for two years was prepared. 5.139 mg of the
spent hydrotreating catalyst 1 was measured out into a platinum pan, set
in a differential thermal analyzer (Thermo Plus 2 series/TGSllO
manufactured by Rigaku Corporation), and subjected to a differential
thermal analysis with elevating a temperature of a sample from room
temperature to 700°C by 10°C/minute at a flow rate of air of 100
ml/minute. Next, Ti and T2 were calculated by the aforementioned
method based on the results of the differential thermal analysis, which
revealed that Ti = 260°C and T2 = 360°C. Deoiling was carried out by
heating the spent hydrotreating catalyst 1 at 300°C for 3 hours in a
18
nitrogen flow having a flow rate per unit volume of the spent catalyst of
15 NL/h-L-catalyst in an electric furnace. After that, a regenerated
catalyst 1 was obtained by regenerating the deoiled catalyst at Ti + 40°C
for 5 hours in an air flow having a flow rate per unit volume of the
catalyst of 50 NL/h-L-catalyst in the electric furnace. Quantitative
determination of a residual carbon content in the obtained regenerated
catalyst 1 was carried out by the aforementioned test method. As a
result, the residual carbon content was 0.7% by mass based on the mass
of the regenerated catalyst.
[0053] (Hydrotreatment reaction)
The regenerated catalyst 1 was packed in a fixed-bed continuous
flow reactor, and at first, pre-sulfiding of the catalyst was carried out.
Specifically, 1% by mass of DMDS was added to a fi-action
corresponding to a gas oil having a density of 851.6 kg/m , a initial
boiling point of 231.0°C and an end boiling point of 376.0°C at a
distillation test, and a sulfur component in terms of a sulfur atom based
on a mass of a feed oil of 1.18% by mass, based on the mass of the
fi-action, and then, this was continuously supplied to the catalyst for 48
hours. After that, a hydrotreatment reaction was conducted by using
the fraction corresponding to a gas oil as a feed oil under the conditions
of a reaction temperature of 380°C, a hydrogen partial pressure of 6
MPa, a LHSV of 1 h'\ and a ratio of hydrogen/oil of 1000 SCF/BBL.
A desulfurization rate constant was obtained based on a sulfur
component content in a product oil. In addition, a desulfurization rate
constant was obtained by carrying out a similar reaction by using a new
catalyst corresponding to the spent catalyst used, and the specific
19
activity of the regenerated catalyst 1 was calculated by the
desulfurization rate constant. The results are shown in Table 1. It is
noted that the analysis on properties of the feed oil and the product oil
was all conducted by the aforementioned test method.
[0054] [Example 2] (Regenerated hydrotreating catalyst)
A regenerated catalyst 2 was obtained by using the same spent
hydrotreating catalyst 1 as that used in Example 1 and by carrying out
regeneration by the same operation as that in Example 1 except that
regeneration conditions were those shown in Table 1. The analysis
results of a residual carbon content in the regenerated catalyst 2 are
shown in Table 1.
[0055] (Hydrotreatment reaction)
A hydrotreatment reaction was carried out by the same operation
as that in Example 1 except that the regenerated catalyst 2 was used.
The results of specific activity are shown in Table 1.
[0056] [Example 3] (Regenerated hydrotreating catalyst)
A spent hydrotreating catalyst 2 which was a catalyst containing
molybdenum and cobalt as active metals supported on an alumina
support and was pulled out after having been used in a hydrotreating
facility for a gas oil for two years was prepared. The spent
hydrotreating catalyst 2 was subjected to a differential thermal analysis,
which revealed that Ti = 310°C and T2 = 410°C. Deoiling was carried
out by heating the spent hydrotreating catalyst 2 at 400°C for 3 hours in
a nitrogen flow having a flow rate per unit volume of the spent catalyst
of 15 NL/h-L-catalyst in an electric fiimace. After that, a regenerated
catalyst 3 was obtained by regenerating the deoiled catalyst at T2 - 10°C
20
for 5 hours in an air flow having a flow rate per unit volume of the
catalyst of 50 NL/h-L-catalyst in the electric furnace. Quantitative
determination of a residual carbon content in the obtained regenerated
catalyst 1 was carried out by the aforementioned test method. As a
result, the residual carbon content was 0.3% by mass based on the mass
of the regenerated catalyst.
[0057] (Hydrotreatment reaction)
A hydrotreatment reaction was carried out by the same operation
as that in Example 1 except that the regenerated catalyst 3 was used.
The results of specific activity are shown in Table 1.
[Example 4] (Regenerated hydrotreating catalyst)
A regenerated catalyst 4 was obtained by using the same spent
hydrotreating catalyst 2 as that used in Example 3 and by carrying out
regeneration by the same operation as that in Example 1 except that
regeneration conditions were those shown in Table 1. The analysis
results of a residual carbon content in the regenerated catalyst 4 are
shown in Table 1.
[0058] (Hydrotreatment reaction)
A hydrotreatment reaction was carried out by the same operation
as that in Example 1 except that the regenerated catalyst 4 was used.
The results of specific activity are shown in Table 1.
[0059] [Comparative Examples 1 to 4] (Regenerated hydrotreating
catalyst)
Regenerated catalysts 5 to 8 were obtained by using the same
spent hydrotreating catalysts 1 and 2 as those used in Examples 1 and 3
and by carrying out regeneration by the same operation as that in
21
Example 1 except that regeneration conditions were those shown in
Table 1. The analysis results of residual carbon contents in the
regenerated catalysts 5 to 8 are shown in Table 1.
[0060] (Hydrotreatment reaction)
Hydrotreatment reactions were carried out by the same
operation as that in Example 1 except that the regenerated catalysts 5 to
8 were used respectively. The results of specific activity are shown in
Table 1.
22
I i F^ I I I I \ I I
^1 al '^ -^ "^ b ^ o
_P^
T3
JJ "^ •§ ^ S^ •-^
I * l | | - - -£F£; -" - o
U OH
•B -^5
§ ^ 1 g,| ^ ^ - H H" ^ d
_p^
• s - s 2 t o ^ ^ ^ ^ 2 ^
- H 5 > ^ g ^ v o v o o T + S 00 -J 00
- I l l " " ^ H-ff: ° -
_P^
• S | ^ g . f . O O o 2 2 o CN S
_^
I 1^___I
y q O ^^
f^
T3
J tl^____l
o -3 >^ o ^ ^
^ ^ i^ "^i ti 1
a -S j ^ " • " • ^ — — a — — — ' ^ — •>
^ ^ «3 S .2 "1= 2 -K .a
t l j on P^ Pii o Pk a 5 CO
[0062] The results in Table 1 show that the residual carbon content is
less than 2.0% by mass and the activity is maintained to be about 95%
or more in comparison with the new catalyst when the spent
hydrotreating catalyst is regenerated at a temperature of Ti - 30°C or
more and T2 + 30°C or less according to the method of the present
invention (Examples 1 to 4). On the other hand, in Comparative
Examples 5 to 8, the activity in comparison with the new catalyst is
about 89% or less and a decrease in the activity is large in each case,
while the same feeding oils as those used in Examples 1 to 4 are
hydrotreated.

CLAIMS
1. A process for producing a regenerated hydrotreating catalyst by
regenerating a spent hydrotreating catalyst in a prescribed temperature
range, wherein
the prescribed temperature range is a temperature range of Ti -
30°C or more and T2 + 30°C or less, as determined by subjecting the
spent hydrotreating catalyst to a differential thermal analysis, converting
a differential heat in a measuring temperature range of 100°C or more
and 600°C or less to a difference in electromotive force, differentiating
the converted value twice by temperature to provide a smallest extreme
value and a second smallest extreme value, and representing a
temperature corresponding to the extreme value on the
lower-temperature side as Ti and a temperature corresponding to the
extreme value on the higher-temperature side as T2.
2. The process for producing a regenerated hydrotreating catalyst
according to claim 1, wherein a residual carbon content in the
regenerated hydrotreating catalyst is 0.2% by mass or more and 3.0% by
mass or less.
3. The process for producing a regenerated hydrotreating catalyst
according to claim 1 or 2, wherein the hydrotreating catalyst is a
catalyst obtained by supporting 10 to 30% by mass of at least one
selected from Group 6 metals of the periodic table and 1 to 7% by mass
of at least one selected from Group 8 to 10 metals of the periodic table,
based on a total mass of the catalyst, on an inorganic support comprising
an oxide of aluminum.
4. The process for producing a regenerated hydrotreating catalyst
25
according to claim 3, wherein the at least one selected from Grroup 6
metals of the periodic table is molybdenum, and the at least o;ie selected
from Group 8 to 10 metals of the periodic table is cobalt and/or nickel.
5. The process for producing a regenerated hydrotreating catalyst
according to any one of claims 1 to 4, wherein the spent hydrotreating
catalyst is regenerated under an air flow having a flow rate per unit
volume of the catalyst of from 20 to 2000 NL/h-L-catalyst for 2 hours or
more.
6. A process for producing a petroleum product, comprising:
a first step of producing a regenerated hydrotreating catalyst by
the process for producing a regenerated hydrotreating catalyst according
to any one of claims 1 to 5; and
a second step of hydrotreating a distillate petroleum fraction by
using the regenerated hydrotreating catalyst obtained in the first step.
7. The process for producing a petroleum product according to
claim 6, wherein operating conditions of the second step are a hydrogen
partial pressure of from 3 to 13 MPa, a LHSV of from 0.05 to 5 h'\ a
reaction temperature of from 200°C to 410°C, a ratio of hydrogen/oil of
from 100 to 8000 SCF/BBL, and distillation properties of a feed oil of
150°C or more and 600°C or less.
8. A regenerated hydrotreating catalyst produced by the process for
producing a regenerated hydrotreating catalyst according to any one of
claims 1 to 5.