U.S. patent application number 12/299215 was filed with the patent office on 2009-12-24 for method for producing hydrocarbon fractions.
This patent application is currently assigned to JAPAN ENERGY CORPORATION. Invention is credited to Koichi Matsushita.
Application Number | 20090314683 12/299215 |
Document ID | / |
Family ID | 38723083 |
Filed Date | 2009-12-24 |
United States Patent
Application |
20090314683 |
Kind Code |
A1 |
Matsushita; Koichi |
December 24, 2009 |
METHOD FOR PRODUCING HYDROCARBON FRACTIONS
Abstract
A method for producing an LPG fraction, a gasoline fraction, a
kerosene fraction, a gas oil fraction, monocyclic aromatic
hydrocarbon and a non-aromatic naphtha fraction from hydrocracked
oil includes hydrocracking hydrocarbon oil containing polycyclic
aromatic hydrocarbon to convert into a light hydrocarbon fraction,
and efficiently and selectively producing monocyclic aromatic
hydrocarbon with higher valuable alkylbenzenes. The method for
producing hydrocarbon fraction comprises subjecting hydrocarbon
feedstock containing polycyclic aromatic hydrocarbon and in which
the ratio of carbons constituting an aromatic ring to the total
carbons in the hydrocarbon oil (the aromatic ring-constituting
carbon ratio) is 35 mole % or more to catalytic cracking in the
presence of hydrogen. 40% or more of a fraction with a boiling
point of 215.degree. C. or higher in the hydrocarbon feedstock is
converted into a fraction with a boiling point lower than
215.degree. C., producing hydrocracked oil containing 30 vol % or
more of monocyclic aromatic hydrocarbon.
Inventors: |
Matsushita; Koichi;
(Saitama, JP) |
Correspondence
Address: |
YOUNG & THOMPSON
209 Madison Street, Suite 500
Alexandria
VA
22314
US
|
Assignee: |
JAPAN ENERGY CORPORATION
Tokyo
JP
|
Family ID: |
38723083 |
Appl. No.: |
12/299215 |
Filed: |
May 17, 2007 |
PCT Filed: |
May 17, 2007 |
PCT NO: |
PCT/JP2007/000529 |
371 Date: |
October 31, 2008 |
Current U.S.
Class: |
208/111.3 ;
208/108; 208/110; 208/111.35; 208/112 |
Current CPC
Class: |
B01J 23/24 20130101;
B01J 21/06 20130101; B01J 35/108 20130101; C10G 47/12 20130101;
C10G 69/06 20130101; B01J 23/30 20130101; C10G 2300/4018 20130101;
C10G 2400/28 20130101; B01J 35/1019 20130101; C10G 69/04 20130101;
B01J 35/10 20130101; C10G 2400/06 20130101; B01J 35/1023 20130101;
B01J 2229/42 20130101; C10G 2400/02 20130101; C10G 47/16 20130101;
B01J 21/14 20130101; B01J 27/053 20130101; B01J 23/10 20130101;
C10G 2400/08 20130101; B01J 21/12 20130101; B01J 23/74 20130101;
C10G 2400/30 20130101; B01J 29/48 20130101; B01J 21/08 20130101;
C10G 2300/1096 20130101; B01J 35/1061 20130101; C10G 2300/301
20130101 |
Class at
Publication: |
208/111.3 ;
208/112; 208/110; 208/108; 208/111.35 |
International
Class: |
C10G 47/04 20060101
C10G047/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 23, 2006 |
JP |
2006-142419 |
Aug 30, 2006 |
JP |
2006-233334 |
Mar 23, 2007 |
JP |
2007-075778 |
Claims
1. A method for producing hydrocarbon fractions comprising a step
of catalytically hydrocracking a hydrocarbon feedstock containing
polycyclic aromatic hydrocarbons and having not less than 35 mol %
of an aromatic ring-constituting carbon ratio, which is the ratio
of carbon atoms constituting aromatic rings to the total number of
carbon atoms of the hydrocarbon oil, in the presence of hydrogen to
convert not less than 40% of the fractions having a boiling point
of not less than 215.degree. C. to fractions having a boiling point
of less than 215.degree. C. and produce a hydrocracked oil
containing 30 vol % or more of monocyclic aromatic
hydrocarbons.
2. The method according to claim 1, wherein the operating
conditions in the hydrocracking step are 2 to 10 MPa of a pressure,
200 to 450.degree. C. of a temperature, 0.1 to 10.0 h.sup.-1 of a
LHSV, 100 to 5000 NL/L of a hydrogen/oil ratio, and not less than
0.5 of an aromatic ring carbon remaining ratio, which is the ratio
of the aromatic ring-constituting carbon ratio of the hydrocracked
oil to the aromatic ring-constituting carbon ratio of the
hydrocarbon feedstock.
3. The method according to claim 1, wherein the hydrocarbon
feedstock is a hydrocarbon oil fraction obtained from a catalytic
cracker, a thermal cracker, an ethylene cracker, a supercritical
fluid cracker, or a catalytic reformer or a mixture of two or more
of these hydrocarbon oil fractions.
4. The method according to claim 1, wherein the hydrocarbon
feedstock has distillation properties of a 10 vol % distillate
temperature of 140 to 230.degree. C. and a 90 vol % distillate
temperature of 230 to 600.degree. C.
5. The method according to claim 1, further comprising a separation
step of obtaining at least two hydrocarbon fractions selected from
an LPG fraction, a gasoline fraction, a kerosene fraction, a gas
oil fraction, a non-aromatic naphtha fraction, and a monocyclic
aromatic hydrocarbons from a hydrocracked oil obtained by
hydrocracking.
6. The method according to claim 1, wherein the hydrocracking
catalyst comprises a carrier which comprises a composite oxide and
a binder combining the composite oxide and at least one metal
selected from the Group VI metals and Group VIII metals of the
periodic table supported on the carrier, and has properties of a
specific surface area of 100 to 800 m.sup.2/g, a median pore
diameter of 3 to 15 nm, and a pore volume occupied by pores with a
pore diameter of 2 to 60 nm of 0.1 to 1.0 mL/g.
7. The method according to claim 6, wherein the composite oxide
contains at least one of silica-alumina, silica-titania,
silica-zirconia, silica-magnesia, silica-alumina-titania,
silica-alumina-zirconia, tungstated zirconia, sulfated zirconia,
and zeolite.
8. The method according to claim 6, wherein the binder comprises at
least one of alumina, silica-alumina, and boria-alumina.
9. The method according to claim 2, wherein the hydrocarbon
feedstock is a hydrocarbon oil fraction obtained from a catalytic
cracker, a thermal cracker, an ethylene cracker, a supercritical
fluid cracker, or a catalytic reformer or a mixture of two or more
of these hydrocarbon oil fractions.
10. The method according to claim 2, wherein the hydrocarbon
feedstock has distillation properties of a 10 vol % distillate
temperature of 140 to 230.degree. C. and a 90 vol % distillate
temperature of 230 to 600.degree. C.
11. The method according to claim 3, wherein the hydrocarbon
feedstock has distillation properties of a 10 vol % distillate
temperature of 140 to 230.degree. C. and a 90 vol % distillate
temperature of 230 to 600.degree. C.
12. The method according to claim 2, further comprising a
separation step of obtaining at least two hydrocarbon fractions
selected from an LPG fraction, a gasoline fraction, a kerosene
fraction, a gas oil fraction, a non-aromatic naphtha fraction, and
a monocyclic aromatic hydrocarbons from a hydrocracked oil obtained
by hydrocracking.
13. The method according to claim 3, further comprising a
separation step of obtaining at least two hydrocarbon fractions
selected from an LPG fraction, a gasoline fraction, a kerosene
fraction, a gas oil fraction, a non-aromatic naphtha fraction, and
a monocyclic aromatic hydrocarbons from a hydrocracked oil obtained
by hydrocracking.
14. The method according to claim 4, further comprising a
separation step of obtaining at least two hydrocarbon fractions
selected from an LPG fraction, a gasoline fraction, a kerosene
fraction, a gas oil fraction, a non-aromatic naphtha fraction, and
a monocyclic aromatic hydrocarbons from a hydrocracked oil obtained
by hydrocracking.
15. The method according to claim 2, wherein the hydrocracking
catalyst comprises a carrier which comprises a composite oxide and
a binder combining the composite oxide and at least one metal
selected from the Group VI metals and Group VIII metals of the
periodic table supported on the carrier, and has properties of a
specific surface area of 100 to 800 m.sup.2/g, a median pore
diameter of 3 to 15 nm, and a pore volume occupied by pores with a
pore diameter of 2 to 60 nm of 0.1 to 1.0 mL/g.
16. The method according to claim 3, wherein the hydrocracking
catalyst comprises a carrier which comprises a composite oxide and
a binder combining the composite oxide and at least one metal
selected from the Group VI metals and Group VIII metals of the
periodic table supported on the carrier, and has properties of a
specific surface area of 100 to 800 m.sup.2/g, a median pore
diameter of 3 to 15 nm, and a pore volume occupied by pores with a
pore diameter of 2 to 60 nm of 0.1 to 1.0 mL/g.
17. The method according to claim 4, wherein the hydrocracking
catalyst comprises a carrier which comprises a composite oxide and
a binder combining the composite oxide and at least one metal
selected from the Group VI metals and Group VIII metals of the
periodic table supported on the carrier, and has properties of a
specific surface area of 100 to 800 m.sup.2/g, a median pore
diameter of 3 to 15 nm, and a pore volume occupied by pores with a
pore diameter of 2 to 60 nm of 0.1 to 1.0 mL/g.
18. The method according to claim 5, wherein the hydrocracking
catalyst comprises a carrier which comprises a composite oxide and
a binder combining the composite oxide and at least one metal
selected from the Group VI metals and Group VIII metals of the
periodic table supported on the carrier, and has properties of a
specific surface area of 100 to 800 m.sup.2/g, a median pore
diameter of 3 to 15 nm, and a pore volume occupied by pores with a
pore diameter of 2 to 60 nm of 0.1 to 1.0 mL/g.
19. The method according to claim 9 wherein the hydrocarbon
feedstock has distillation properties of a 10 vol % distillate
temperature of 140 to 230.degree. C. and a 90 vol % distillate
temperature of 230 to 600.degree. C.
20. The method according to claim 9 further comprising a separation
step of obtaining at least two hydrocarbon fractions selected from
an LPG fraction, a gasoline fraction, a kerosene fraction, a gas
oil fraction, a non-aromatic naphtha fraction, and a monocyclic
aromatic hydrocarbons from a hydrocracked oil obtained by
hydrocracking.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for producing
various hydrocarbon fractions by hydrocracking specific hydrocarbon
oils containing polycyclic aromatic hydrocarbons. More
particularly, the present invention relates to a method for
producing hydrocarbon fractions by obtaining a hydrocracked oil
which selectively contains a large amount of monocyclic aromatic
hydrocarbons and then efficiently producing light hydrocarbon
fractions such as an LPG fraction, a gasoline fraction, a kerosene
fraction, a gas oil fraction, a non-aromatic naphtha fraction, and
a monocyclic aromatic hydrocarbon.
BACKGROUND ART
[0002] In recent years, the demand of petroleum products tends to
lighten, particularly, petrochemical feeds represented by BTX
(benzene, toluene, and xylene), is increasing more and more.
Furthermore, in addition to BTX, aromatic hydrocarbons are widely
used as a gasoline blending stock due to the generally high octane
value. A fluid catalytic cracking process can be given as a method
for producing fractions containing monocyclic aromatic hydrocarbons
represented by BTX. Although the method can produce about 50 vol %
of a naphtha fraction, the content of monocyclic aromatic
hydrocarbons in the naphtha fraction is about 20% at most, and the
content of BTX is less than 10%. A catalytic reforming process can
also be given as a method for selectively producing aromatic
hydrocarbons. However, the feed for the catalytic reforming process
is limited to naphtha fractions having the same boiling point
range, whereby restrained quantitatively. For this reason, in order
to deal with diversification of feeds and to get more inexpensive
feeds, a method for producing monocyclic aromatic hydrocarbons from
fractions heavier than BTX has been desired.
[0003] In addition to the fluid catalytic cracking process, a
vacuum gas oil hydrocracking process has been widely adopted as a
method for producing light hydrocarbon oils by cracking of heavy
oils. In the vacuum gas oil hydrocracking method, the target
fractions are obtained by causing a feed to come in contact with a
catalyst at a high temperature in the presence of high pressure
hydrogen gas. These methods have been generally used for producing
only fractions such as gas oils and jet fuels with a boiling point
of about 150 to 370.degree. C. in the past. Therefore, a method of
obtaining a product having desired properties for use as gas oils
and jet fuels, that is, a method of possibly minimizing the
aromatic content has been adopted.
[0004] On the other hand, in regard to various oil stocks obtained
from petroleum refining processes, the consumption of fractions
with high sulfur content or a high aromatic content tends to
decrease as a fuel oil from the view of domestic and international
environmental measure. For example, since the gas oil fraction,
which is also called light cycle oil (LCO), obtained from a fluid
catalytic cracking process or the gas oil fraction obtained from a
thermal cracking process has a high sulfur content or a high
polycyclic aromatic content, these fractions discharge sulfur oxide
and particulate matter when used for a diesel fuel. Therefore, it
is difficult to blend a large amount of these fractions.
[0005] Patent Document 1 describes the use of LCO and the like as
feed for a hydrocarbon conversion reaction. However, the proposed
method is still just a technique for producing gas oil and
kerosene. Patent Document 1 does not describe production of
aromatic compounds represented by BTX. Patent Document 2 discloses
a method of treating aromatic hydrocarbons with hydrogen to reduce
particulate matter generated during combustion. However, the object
of the technology is to produce chain hydrocarbons by reducing
aromatics. Patent Document 3 discloses a method for hydrogenating a
polycyclic aromatic compound using a solid catalyst. The method
aims to produce gas oil having an improved cetane number. This is
not such a technology that reduces the molecular weight of the
polycyclic aromatic compounds and converts the compounds even into
a feed for petrochemical. The Patent Documents 4 and 5 propose
methods for producing gasoline fractions by hydrocracking of LCO
fractions. These methods aim to control the conversion rate to
gasoline fractions by a comparatively mild reaction in order to
have a certain amount of gas oil fractions remain. Patent Document
6 discloses a method for producing kerosene fractions, gas oil
fractions, and naphtha fractions by hydrocracking a mixture of LCO
fractions and VGO (vacuum gas oil) fractions. The main purpose of
the method is production of kerosene and gas oil fractions.
Preferential production of BTX is not intended.
[0006] Patent Document 7 discloses a method for lightening heavy
aromatic hydrocarbons having nine or more carbon numbers, but
contains no description on the number of aromatic rings. The
difficulty of converting aromatic hydrocarbons having two or more
rings to monocyclic aromatic hydrocarbons is not recognized.
Non-patent Document 1 proposes a method for partially producing BTX
using LCO as feed. However, the object of the method is production
of diesel oil and gasoline. This is not a method for preferentially
producing BTX. Non-patent Document 2 also discloses a method for
producing high octane gasoline by hydrocracking
1-methylnaphthalene, which is a bicyclic aromatic hydrocarbon
contained in LCO fractions in large quantity. However, since the
reaction produces a large amount of cycloparaffins and
isoparaffins, the octane number of the product is still low as
about 85. This is thus not a method for selectively producing
monocyclic aromatic hydrocarbons.
[0007] As described above, although many methods for producing
naphthenes by hydrogenating the aromatic nuclei of polycyclic
aromatic hydrocarbons or methods for partially hydrogenating the
aromatic nuclei of polycyclic aromatic hydrocarbons are disclosed,
there has never been established method for selectively producing
alkylbenzenes represented by BTX using heavy hydrocarbon as a feed.
[0008] [Patent Document 1] JP-A-2004-148314 [0009] [Patent Document
2] JP-A-H08-183962 [0010] [Patent Document 3] JP-A-2000-226589
[0011] [Patent Document 4] Japanese Patent No. 3001963 [0012]
[Patent Document 5] JP-B-H03-170598 [0013] [Patent Document 6] WO
2006/062712 [0014] [Patent Document 7] Japanese Patent No. 3302553
[0015] [Non-patent Document 1] Thakkar et al., National
Petrochemical & Refiners Association, Annual Meeting, AM-05-53
(2005) [0016] [Non-patent Document 2] Demirel et al., Fuel, Vol.
77, No. 4, p 301-311 (1998)
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0017] Under the above circumstances, an object of the present
invention is to provide a method for producing at least two
hydrocarbon fractions selected from an LPG fraction, a gasoline
fraction, a kerosene fraction, a gas oil fraction, a monocyclic
aromatic hydrocarbon fraction, and a non-aromatic naphtha fraction
from the hydrocracked oil, by hydrocracking a hydrocarbon fraction
containing polycyclic aromatic hydrocarbons to convert into light
hydrocarbon fractions without causing a problem such as coking, at
the same time efficiently and selectively forming monocyclic
aromatic hydrocarbons which are high value-added alkylbenzenes.
Means for Solving the Problems
[0018] As a result of extensive studies, the inventor of the
present invention has found that monocyclic aromatic hydrocarbons
represented by alkylbenzenes and various light hydrocarbon
fractions can be efficiently produced by selecting the type of
carbon structures constituting the hydrocarbon feeds used for
hydrocracking and the operating conditions and highly controlling
the balance of the hydrogenation activity and cracking activity in
the hydrocracking. This finding has led to the concept of the
method for producing hydrocarbon fractions of the present
invention.
[0019] Specifically, the present invention is a method as described
below.
[0020] (1) A method for producing hydrocarbon fractions comprising
a step of catalytically hydrocracking a hydrocarbon feedstock
containing polycyclic aromatic hydrocarbons and having not less
than 35 mol % of an aromatic ring-constituting carbon ratio, which
is the ratio of carbon atoms constituting aromatic rings to the
total number of carbon atoms of the hydrocarbon feedstock, in the
presence of hydrogen to convert not less than 40% of the fractions
having a boiling point of not less than 215.degree. C. to fractions
having a boiling point of less than 215.degree. C. and produce a
hydrocracked oil containing 30 vol % or more of monocyclic aromatic
hydrocarbons.
[0021] (2) The method according to (1), wherein the operating
conditions in the hydrocracking step are 2 to 10 MPa of a pressure,
200 to 450.degree. C. of a temperature, 0.1 to 10.0 h.sup.-1 of a
LHSV, 100 to 5000 NL/L of a hydrogen/oil ratio, and not less than
0.5 of an aromatic ring carbon remaining ratio, which is the ratio
of the aromatic ring-constituting carbon ratio of the hydrocracked
oil to the aromatic ring-constituting carbon ratio of the
hydrocarbon feedstock.
[0022] (3) The method according to (1) or (2), wherein the
hydrocarbon feedstock is a hydrocarbon oil fraction obtained from a
catalytic cracker, a thermal cracker, an ethylene cracker, a
supercritical fluid cracker, or a catalytic reformer or a mixture
of two or more of these hydrocarbon oil fractions.
[0023] (4) The method according to any one of (1) to (3), wherein
the hydrocarbon feedstock has distillation properties of a 10 vol %
distillate temperature of 140 to 230.degree. C. and a 90 vol %
distillate temperature of 230 to 600.degree. C.
[0024] (5) The method according to any one of (1) to (4), further
comprising a separation step of obtaining at least two hydrocarbon
fractions selected from an LPG fraction, a gasoline fraction, a
kerosene fraction, a gas oil fraction, a non-aromatic naphtha
fraction, and a monocyclic aromatic hydrocarbons from a
hydrocracked oil obtained by hydrocracking.
[0025] (6) The method according to any one of (1) to (5), wherein
the hydrocracking catalyst comprises a carrier which comprises a
composite oxide and a binder combining the composite oxide and at
least one metal selected from the Group VI metals and Group VIII
metals of the periodic table supported on the carrier, and has
properties of a specific surface area of 100 to 800 m.sup.2/g, a
median pore diameter of 3 to 15 nm, and a pore volume occupied by
pores with a pore diameter of 2 to 60 nm of 0.1 to 1.0 mL/g.
[0026] (7) The method according to (6), wherein the composite oxide
contains at least one of silica-alumina, silica-titania,
silica-zirconia, silica-magnesia, silica-alumina-titania,
silica-alumina-zirconia, tungstated zirconia, sulfated zirconia,
and zeolite.
[0027] (8) The method according to (6), wherein the binder
comprises at least one of alumina, silica-alumina, and
boria-alumina.
EFFECT OF THE INVENTION
[0028] According to the method for producing hydrocarbon fractions
of the present invention, high-boiling-point hydrocarbon fractions
are converted into low-boiling-point hydrocarbon fractions, and
also high value-added alkylbenzenes (monocyclic aromatic
hydrocarbons) represented by BTX are efficiently produced by using
a hydrocarbon oil containing a large amount of polycyclic aromatic
hydrocarbons as a feed and contacting the hydrocarbon oil with an
optimal hydrocracking catalyst in the presence of hydrogen, while
avoiding catalyst poisoning. In addition, since a hydrocracking
catalyst which is most suitable for the hydrocracking and has a
specified composition and specified properties suitably balanced in
hydrocracking activity and hydrogenation activity is used, gas
generation by excessive cracking can be controlled and a decrease
in the activity by coking due to insufficiency of hydrogenation
activity can be suppressed. In addition to the capability of
producing alkylbenzenes at a high efficiency and a high
selectivity, an LPG fraction, a gasoline fraction, a kerosene
fraction, a gas oil fraction, a non-aromatic naphtha fraction, and
a monocyclic aromatic hydrocarbons can be obtained by separating
the resulting hydrocracked oil using an appropriate known method.
These fractions can be effectively used as a low-sulfur-content LPG
blending stock, a high-octane-number low-sulfur-content gasoline
blending stock, a low-sulfur-content kerosene blending stock, a
high-cetane-number low-sulfur-content gas oil blending stock, a
low-sulfur-content non-aromatic naphtha stock and a petrochemical
feed and contribute to a reduction of environmental load.
BEST MODE FOR CARRYING OUT THE INVENTION
[0029] The term "polycyclic aromatic hydrocarbons" used in the
present invention refers to hydrocarbons having two or more
aromatic rings, and the term "monocyclic aromatic hydrocarbon"
refers to compounds which hydrogen atoms of benzene are
unsubstituted with 0 to 6 chain hydrocarbon groups, and are also
called "alkylbezenes". The term "1.5-cyclic aromatic hydrocarbons"
refers to compounds having one aromatic ring and one saturated
naphthenic ring in a molecule such as
tetralin(1,2,3,4-tetrahydronaphthalene) and
indan(2,3-dihydroindene).
[0030] The method for producing hydrocarbon fractions of the
present invention will now be described in detail in the order of
feeds for hydrocracking reaction, pre-treatment step, hydrocracking
reaction, hydrocracking catalyst, production method of
hydrocracking catalyst, refining method of hydrocracked oil, and
product hydrocarbons.
[Feeds for Hydrocracking Reaction]
[0031] The hydrocarbon oil used as the feed for the hydrocracking
reaction in the present invention contains polycyclic aromatic
hydrocarbons. In the hydrocarbon oil, the ratio of carbon atoms
constituting aromatic rings to the total number of carbon atoms of
the hydrocarbon oil (the aromatic ring-constituting carbon ratio)
is not less than 35 mol %, preferably not less than 40 mol %, and
particularly preferably not less than 45 mol %. If the ratio of
carbon atoms constituting aromatic rings to the total number of
carbon atoms is less than 35 mol %, the aimed monocyclic aromatic
hvdrocarbons (alkylbenzenes) cannot unpreferably be obtained at a
high yield. The aromatic ring-constituting carbon ratio can be
calculated by analyzing .sup.13C-NMR using a nuclear magnetic
resonance apparatus (NMR).
[0032] More is not necessarily better for the number of aromatic
rings. From the viewpoint of eventually producing monocyclic
aromatic compounds preferentially, preferable polycyclic
hydrocarbons in the feed are bicyclic aromatic hydrocarbons. In
particular, a feed containing a small amount of tri-ring or larger
polycyclic aromatics hydrocarbons and a large amount of 1.5 ring
and 2-ring aromatic hydrocarbons is preferable. The amount of the
tri- or larger polycyclic aromatic hydrocarbons is preferably 5.0
vol % or less, more preferably 3.0 vol % or less, and particularly
preferably 1.0 vol % or less; and the amount of the bi- or larger
polycyclic aromatic hydrocarbons is preferably 10 vol % or more,
more preferably 20 vol % or more, and particularly preferably 30
vol % or more. A feed containing 50 vol % or more, more preferably
60 vol % or more, and particularly preferably 70 vol % or more of
aromatic hydrocarbons with less than tricyclic aromatic
hydrocarbons (the total of mono-cyclic, 1.5-ring and 2-ring
aromatic hydrocarbons) is preferably used.
[0033] Preferable distillation properties may be determined based
on the above aromatic composition. Specifically, taking the boiling
point (218.degree. C.) of naphthalene of bicyclic aromatic
hydrocarbon into account, at least the content of 215 to
280.degree. C. fractions is 10 vol % or more, and the content of
215.degree. C. or higher fractions is 30 vol % or more, and more
preferably 40 vol % or more. Therefore, as preferable distillation
properties of feeds, 10% distillation temperature is 100 to
230.degree. C., more preferably 140 to 230.degree. C., and still
more preferably 150 to 220.degree. C., and 90% distillation
temperature is 230 to 600.degree. C., more preferably 230 to
400.degree. C., and still more preferably 230 to 310.degree. C.,
and particularly preferably 265 to 300.degree. C.
[0034] As inhibitory substances to the hydrocracking reaction,
usually 0.1 to 3,000 wt ppm of nitrogen and 0.1 to 3 wt % of sulfir
are contained in feeds for the hydrocracking reaction. Main sulfur
compounds include benzothiophenes, dibenzothiophenes, and sulfides.
In the boiling range of the feed used in the present invention,
benzothiophenes and dibenzothiophenes are included in large amount.
Since dibenzothiophene is known to be stable due to the
electronically delocalized structure and to react only with
difficulty, the feed used in the present invention preferably does
not contain dibenzothiophene too much.
[0035] Any hydrocarbon oil may be used as the hydrocarbon oil
containing polycyclic aromatic hydrocarbons used as feed for the
hydrocracking reaction of the present invention, insofar as the
ratio of carbon atoms constituting an aromatic ring to the total
number of carbon atoms of the hydrocarbon oil (aromatic
ring-constituting carbon ratio) is 35 mol % or more, and the
hydrocarbon oil contains 30 vol % or more of fractions having a
boiling point of 215.degree. C. or more.
[0036] Specifically, fractions obtained by atmospheric distillation
of crude oil, vacuum gas oil obtained by vacuum distillation of
atmospheric residue, distillates obtained by various heavy oil
cracking processes (catalytic cracker, thermal cracker, etc.) such
as catalytic cracking oil (particularly LCO) obtained from a
catalytic cracker and thermal cracking oil obtained from a thermal
cracker (a coker, a visbreaker, etc.), ethylene cracker heavy
residue obtained from an ethylene cracker, catalytic reformate
obtained from a catalytic reformer, an aromatic-rich catalytic
reformate obtained from the catalytic reformate by further
extraction, distillation, or membrane separation ("aromatic-rich
catalytic reformate" herein refers to fractions obtained from a
catalytic reformer consisting of aromatic compounds with 10 or more
carbon numbers and containing 50 vol % or more of aromatic
compounds), fractions obtained from an aromatic extraction process
for producing lubricating base oil, aromatic-rich fractions
obtained from a solvent dewaxing process, and the like can be
given. Other hydrocarbon fractions obtained by a desulfurization
process or a hydroconversion process (for examples heavy oil
cracking processes such as an H-Oil process and an OCR process and
a supercritical fluid cracking process of heavy oil) which refines
an atmospheric distillation residue, a vacuum distillation residue,
a dewaxed oil, oil sand, oil shale, coal, and biomass may be also
preferably used.
[0037] Distillates obtained by two or more of the above-mentioned
refining units in any optional order may also be used as the
hydrocarbon feedstock for the hydrocracking reaction. These
hydrocarbon feedstocks may be used alone or in combination of two
or more insofar as the above-mentioned boiling point range and
aromatic ring-constituting carbon ratio are satisfied the
definition of hydrocarbon feedstock for the hydrocracking reaction.
The hydrocarbon feedstocks having a boiling point range and
aromatic ring-constituting carbon ratio outside of the
above-mentioned range may also be used by adjusting the boiling
point range and the aromatic ring-constituting carbon ratio to fall
within the above ranges. Among the above-mentioned hydrocarbon
feedstocks, the catalytic cracking oil, thermal cracking oil,
vacuum gas oil, ethylene cracker heavy residue, catalytic
reformate, and supercritical fluid decomposition oil are
preferable, with the light cycle oil (LCO) being particularly
preferable.
[Pre-Treatment Step]
[0038] Polycyclic aromatic hydrocarbons are selectively converted
into monocyclic aromatic hydrocarbons by hydrocracking in the
present invention, and it is also possible to pre-treat the
polycyclic aromatic hydrocarbons before the hydrocracking as
required. There are many feeds for the hydrocracking reaction as
mentioned above, and the contents of the sulfur compounds and
nitrogen compounds which is contained in the feeds are also
various. The hydrocracking catalyst may not fully function
particularly when the concentration of the sulfur compounds and
nitrogen compounds is too high. Therefore, it is preferable to
previously reduce the sulfur content and the nitrogen content by
using a known method as a pre-treatment step prior to the
hydrocracking step. As the pre-treatment method, hydrorefining,
adsorption separation, sorption separation, oxidation, and the like
can be given. Among these, hydrorefining is particularly
preferable. When the hydrorefining method is used, the
hydrocracking reaction feed is caused to come in contact with a
hydrorefining catalyst in the presence of hydrogen at a temperature
of preferably 150 to 400.degree. C., more preferably 200 to
380.degree. C., and still more preferably 250 to 360.degree. C.,
under a pressure preferably of 1 to 10 MPa, and more preferably 2
to 8 MPa, at an liquid hourly space velocity (LHSV) preferably of
0.1 to 10.0 h.sup.-1, more preferably 0.1 to 8.0 h.sup.-1, and
still more preferably 0.2 to 5.0 h.sup.-1, at a
hydrogen/hydrocarbon oil ratio by volume preferably of 100 to 5,000
NL/L, and more preferably 150 to 3,000 NL/L.
[0039] By the above treatment, the sulfur content is reduced
preferably to 500 ppm by weight or less, more preferably 100 ppm by
weight or less, and particularly preferably 50 ppm by weight or
less; and the nitrogen content is reduced preferably to 50 ppm by
weight or less, more preferably 20 ppm by weight or less, and
particularly preferably 10 ppm by weight. Along with the
desulfurization and denitrification by this hydrorefining
treatment, hydrogenation of aromatic compounds may be also
partially proceeded. In the present invention, reducing the amount
of polycyclic aromatic hydrocarbons causes no problem, but it is
undesirable to reduce the amount of monocyclic aromatic
hydrocarbons. Therefore, it is preferable to treat under the
reaction conditions which the hydrogenation can be stopped when the
polycyclic aromatic hydrocarbons have been hydrogenated to
monocyclic or 1.5-cyclic aromatic hydrocarbons. To this end, it is
preferable to control the hydrogenation reaction so that the
remaining amount (on a volume basis) of the total aromatic
hydrocarbons after the reaction is 0.90 or more of the amount
before the reaction, more preferably 0.95 or more, and still more
preferably 0.98 or more.
[0040] There are no specific limitations to the hydrorefining
catalyst used in the pre-treating hydrofinishing step. A catalyst
containing at least one metal selected from the Group VI or the
Group VIII of the Periodic Table supported on a refractory oxide
carrier is preferably used. As specific examples of such a
catalyst, catalysts containing at least one metal selected from
molybdenum, tungsten, nickel, cobalt, platinum, palladium, iron,
ruthenium, osmium, rhodium, and iridium as the Group VI metals or
the Group VIII metals of the Periodic Table supported on a carrier
comprising at least one selected from alumina, silica, boria, and
zeolite can be given. The hydrorefining catalysts are used after
treatments such as drying, reducing, sulfiding, and the like before
hydrogenation as required. The amount of the catalyst used in the
pre-treatment step is preferably from 10 to 200 vol % of the amount
of the hydrocracking catalyst. If the amount of the catalyst is 10
vol % or less, the sulfur removal is insufficient; on the other
hand, if 200 vol % or more, a large unit is required, which makes
it inefficient. The pre-treatment step and the hydrocracking step
may be carried out in one reaction column having separate catalyst
layers filled with respective catalysts or may be carried out in
the separate reaction columns. In order to accelerate the reaction,
a hydrogen feed line may be installed between the two catalyst
layers, and a gas discharge line for the reacted gas may be
installed upstream of the hydrogen feed line to discharge the
reacted gas and to introduce fresh hydrogen gas. It is needless to
mention that the pre-treatment step and the hydrocracking step may
respectively be carried out in separate units.
[Hydrocracking Reaction]
[0041] In the hydrocracking reaction of the present invention, a
hydrocarbon oil is contacted with a hydrocracking catalyst which is
described later in detail in the presence of hydrogen to convert
40% or more, preferably 50% or more of the fractions having a
boiling point of 215.degree. C. or more to fractions having a
boiling point of less than 215.degree. C., thereby producing
various light hydrocarbon fractions, including monocyclic aromatic
hydrocarbons. Specifically, a hydrocracked oil containing 30% or
more of the monocyclic aromatic hydrocarbons and other various
light hydrocarbon fractions is produced from a hydrocarbon
feedstock by converting hydrocarbon fractions having a boiling
point higher than a specified temperature in the hydrocarbon
feedstock, in other words, by converting polycyclic hydrocarbons
into monocyclic aromatic hydrocarbons (alkyl benzenes) by reducing
the number of aromatic rings of the polycyclic aromatic
hydrocarbons.
[0042] The reaction configurations for hydrocracking hydrocarbon
oil in the present invention are not particularly limited. A
generally used reaction configuration such as a fixed bed,
ebullating bed, fluidized bed, moving bed, and the like may be
used. Among these, a fixed bed reaction is preferable because of
the simple equipment composition and ease of operation.
[0043] The hydrocracking catalyst used in the hydrocracking of
hydrocarbon oil in the present invention is filled into a reactor
and subject to a pre-treatment such as drying, reducing, sulfiding,
and the like prior to the use for hydrocracking. These methods of
pre-treatment are commonly known to a person having an ordinary
skill in the art and carried out in the reaction column or outside
of the reaction column by a well-known method. The activation of
the catalyst by sulfiding is generally carried out by treating the
hydrocracking catalyst in a stream of a mixture of hydrogen and
hydrogen sulfide at 150 to 800.degree. C., and preferably 200 to
500.degree. C.
[0044] Hydrocracking operation conditions such as reaction
temperature, reaction pressure, hydrogen flow rate, liquid hourly
space velocity, and the like may be appropriately adjusted
according to the properties of the feed, the quality of the product
oil, the production amount, and the capability of the refining and
post-treatment facilities. The hydrocracking reaction feed is
contacted with the hydrocracking catalyst in the presence of
hydrogen at a temperature of 200 to 450.degree. C., more preferably
250 to 430.degree. C., and still more preferably 280 to 400.degree.
C. under a pressure of 2 to 10 MPa, and more preferably 2 to 8 MPa
at a LHSV of 0.1 to 10.0 h.sup.-1, more preferably 0.1 to 8.0
h.sup.-1, and still more preferably 0.2 to 5.0 h.sup.-1 at a
hydrogen/hydrocarbon oil ratio (by volume) of 100 to 5000 NL/L, and
preferably 150 to 3000 NL/L. Polycyclic aromatic hydrocarbons in
the hydrocarbon feedstock for the hydrocracking reaction are
decomposed and converted into desired monocyclic aromatic
hydrocarbons (alkylbenzenes) by hydrocracking under the above
conditions. Operation conditions outside the above range are
undesirable because of insufficient cracking activities, rapid
degradation of the catalyst, and the like.
[Hydrocracking Catalyst]
[0045] The hydrocracking catalyst of the present invention
comprises a carrier made from a composite oxide and a binder which
bonds the composite oxide and at least one metal selected from the
Group VI and the Group VIII of the periodic table, supported on the
carrier. The catalyst is shaped into the form of pellet
(cylindrical pellet, particular shaped pellet), granule, sphere,
and the like. The catalyst preferably has a specific surface area
of 100 to 800 m.sup.2/g, a median pore diameter of 3 to 15 nm, and
a pore volume occupied by pores with a diameter of 2 to 60 nm of
0.1 to 1.0 mL/g.
[0046] The specific surface area is a value of the BET specific
surface area which is determined by nitrogen adsorption based on
ASTM D3663-78. A more preferable specific surface area is 150 to
700 m.sup.2/g, and still more preferably 200 to 600 m.sup.2/g. If
the BET specific surface area is smaller than the above-mentioned
range, dispersion of the active metal is insufficient and the
activity is not increased. If the BET specific surface area is
larger than the above range on the other hand, sufficient pore
volume cannot be retained, thus the reaction products are not
sufficiently dispersed, and progress of reaction may be rapidly
inhibited, unpreferably.
[0047] The median pore diameter of the hydrocracking catalyst is
more preferably 0.4 to 12 nm, and particularly preferably 5.0 to 10
nm. The pore volume occupied by pores with a diameter of 2 to 60 nm
is more preferably 0.15 to 0.8 mL/g, and particularly preferably
0.2 to 0.7 mL/g. Since there are appropriate ranges for the median
pore diameter and pore volume in relation to the size of the
molecules involved in the reaction and dispersion of the molecules,
either too large or too small values of the median pore diameter or
pore volume is not preferable.
[0048] Pore characteristics of so-called mesopores, that is, the
above mentioned pore diameter and pore volume, can be measured by a
nitrogen gas absorption method and the relationship between the
pore volume and pore diameter can be calculated by the BJH method
or the like. The median pore diameter is defined as a pore diameter
corresponding to an accumulated pore volume when the accumulated
pore volume is one half of total pore volume (V) in an accumulated
pore volume curve obtained by accumulating all of the volume of
each pore diameter, wherein the total pore volume (V) is the
accumulation of the pore volume occupied by the pores with a
diameter of 2 to 60 nm, and determined under a relative pressure of
0.9667 in the nitrogen gas absorption method.
[0049] A catalysts having macropores, mesopores, or micropores may
be used as the hydrocracking catalyst in the present invention.
Since the mesopore characteristics of a composite oxide carrier can
be usually maintained until the catalyst is formed, the mesopore
characteristics of the hydrocracking catalyst can be basically
adjusted by controlling kneading conditions (time, temperature,
torque) and calcining conditions (time, temperature, kind and flow
rate of circulation gas) so that the composite oxide carrier may
have the above mesopore characteristics.
[0050] The macropore characteristics may be adjusted by controlling
the voids between the composite oxide particles and the content of
binder. The voids between the composite oxide particles may be
controlled by the diameter of the composite oxide particles and the
content may be controlled by the blending amount of binder.
[0051] The micropore characteristics largely depend on the pores
inherently possessed by composite oxides such as zeolite, but it
may also be controlled by dealuminization treatment such as
steaming and the like.
[0052] The pore characteristics of mesopores and macropores may
further be affected by the properties and kneading conditions of
the binder which are mentioned later. The composite oxide is mixed
with an inorganic oxide matrix (binder) to prepare the carrier.
[Composite Oxide]
[0053] The composite oxide as used in the present invention refers
to a composite oxide with solid acidity. For example, there are
known many binary composite oxides, in addition to the composite
oxides of which acidity exhibition is confirmed in K. Shibata, T.
Kiyoura, J. Kitagawa, K. Tanabe, Bull. Chem. Soc. Jpn., 46, 2985
(1973). Among such composite oxides, silica-alumina,
silica-titania, silica-zirconia, and silica-magnesia may be
preferably used as a composite oxide used in the present invention.
As ternary composite oxides, silica-alumina-titania and
silica-alumina-zirconia can be preferably used. The composite oxide
as used in the present invention includes zeolite such as a USY
zeolite.
[0054] Either one or two or more of the composite oxides selected
from silica-alumina, silica-titania, silica-zirconia,
silica-magnesia, silica-alumina-titania, silica-alumina-zirconia,
tungstated zirconia, sulfated zirconia, alumina sulfate, and
zeolite may be used alone or in a combination as the composite
oxides, respectively. In particular, when silica-alumina is used as
the composite oxide, the silica/alumina ratio (molar ratio) is
preferably 1 to 20.
[0055] Although there are no particular limitations with respect to
the zeolite, the zeolite is preferably an X-type, a Y-type, a
.beta.-type, an MOR-type, or an MFI-type zeolite, among them a
Y-type, a .beta.-type, or an MFI-type zeolite may be particularly
suitably used. Among the Y-type zeolites, an acidic zeolite such as
H--Y-type zeolite obtained by ion-exchanging the alkali metal is
more preferable than the alkali metal type such as a Na--Y-type
zeolite. A USY-type zeolite (ultra stable Y-type zeolite) obtained
by dealuminization of an H--Y-type zeolite may also be used. The
USY-type zeolite is obtained by an acid treatment, a high
temperature treatment, a steam treatment, and the like, and is
characterized in that it has strong resistance against crystalline
deterioration, an alkali metal ion content of less than 1.0 wt %,
preferably less than 0.5 wt %, a lattice constant of 2.46 nm or
less, and a silica/alumina (SiO.sub.2/Al.sub.2O.sub.3) molar ratio
of 5 or more.
[0056] Any H--Y-type zeolite and USY-type zeolite may be used in
the present invention without a problem irrespective of he
production method insofar as the zeolite has a aluminum: silicon
molar ratio of 1:2.0 to 1:10.0 and a faujasite structure. In the
present invention, it is preferable that a crystalline
aluminosilicate having a lattice constant of 2.43 to 2.46 nm is
obtained by dealkalizing the Y-type zeolite in the first instance,
followed by a steam treatment and/or an acid treatment. If the
lattice constant is more than 2.46 nm, the crystal structure may be
collapsed, and the cracking activity of the catalyst and the yield
of the aimed fractions decrease when the aluminosilicate is caused
to come in contact with an aqueous solution with a pH of less than
3 during the acid treatment described later. The aluminosilicate
having a lattice constant of less than 2.43 nm has poor
crystallinity and also poor acidity. The catalyst has low cracking
activity and produces the objective fractions only at a low yield.
The lattice constant is calculated using the lattice spacing d
obtained by the X-ray diffraction method according to the following
equation.
Lattice constant=d.times.(h.sup.2+k.sup.2+l.sup.2).sup.1/2
wherein h, k, and l are miller's indices.
[0057] The dealkalization is carried out by dipping a Y-type
zeolite in an ammonia containing solution or the like to
ion-exchange an alkali metal such as Na.sup.+ with ammonium ions or
the like, and calcining the resulting product. In this way a
H--Y-type zeolite is firstly obtained, and a USY (ultra stable
Y)-type zeolite with a further reduced alkali metal content can be
prepared by repeating the above series of treatment several times
via an SY (stable Y)-type zeolite. The alkali metal content of
dealkalized USY-type zeolite is preferably less than 1.0 wt %, and
more preferably less than 0.5 wt %.
[0058] The steam treatment may be carried out by causing the
dealkalized zeolite to come in contact with steam of 500 to
800.degree. C., and preferably 550 to 750.degree. C. The acid
treatment may be carried out by dipping the zeolite in an aqueous
nitric acid solution with pH3 or less or the like. Either one of
the steam treatment and acid treatment may be applied effectively,
but crystalline aluminosilicate having the above-mentioned lattice
constant may be prepared by partially dealuminizing using in
combination of both steam treatment and acid treatment, followed by
drying and calcining.
[0059] In addition to the Y-type zeolite, an MOR-type zeolite
represented by .beta.-type zeolite and mordenite, and an MFI-type
zeolite represented by ZSM-5 may also be used. Since these types of
zeolites have a high silica/alumina ratio, these may be used
without particularly applying a dealuminization treatment.
[0060] The crystalline aluminosilicate of which the silica/alumina
ratio is adjusted in this manner may be converted into transition
metal-containing crystalline aluminosilicate or a rare
earth-containing crystalline aluminosilicate by dipping in a
solution containing a salt of a transition metal such as iron,
cobalt, nickel, molybdenum, tungsten, copper, zinc, chromium,
titanium, vanadium, zirconia, cadmium, tin, or lead, or a salt of a
rare earth such as lanthanum, cerium, ytterbium, europium, or
dysprosium to introduce these metal ions. The crystalline
aluminosilicate, transition metal-containing crystalline
aluminosilicate, and rare earth-containing crystalline
aluminosilicate may be used alone or in combination of two or more
thereof when using in the hydrocracking reaction described
later.
[Binder]
[0061] As a binder, a porous and amorphous material such as
alumina, silica-alumina, titania-alumina, zirconia-alumina,
boria-alumina, and the like may be suitably used. Of these,
alumina, silica-alumina, and boria-alumina are preferable because
of the high strength bonding with a composite oxide and high
specific surface area. These inorganic oxide not only have a
function for supporting an active metal, but also have a function
as a binder bonding with the composite oxide and serve to increase
the catalyst strength. The specific surface area of the binder is
preferably 30 m.sup.2/g or more.
[0062] Fine particles of aluminum hydroxide and/or hydrated
aluminum oxide (hereinafter may be referred to simply as "alumina
powder"), particularly aluminum oxide monohydrate having a boehmite
structure such as pseudo-boehmite (hereinafter may be referred to
as simply "alumina") may be preferably used as a binder, which is
one of the components of the carrier, because of their capability
of increasing hydrocracking activity and selectivity. Fine
particles of aluminum hydroxide and/or hydrated aluminum oxide
containing boria (boron oxide), particularly aluminum oxide
mono-hydrate having a boehmite structure such as pseudo-boehmite
containing boria may also be preferably used as a binder because of
their capability of increasing hydrocracking activity and
selectivity.
[0063] As aluminum oxide mono-hydrate, commercially available
alumina sources (for example, PURAL (registered trademark), CATAPAL
(registered trademark), DISPERAL (registered trademark), and DISPAL
(registered trademark) commercially produced by SASOL, VERSAL
(registered trademark) commercially produced by UOP and HIQ
(registered trademark) commercially produced by ALCOA, and the
like) may be used. It is also possible to prepare aluminum oxide
mono-hydrate by the commonly known method of partially dehydrating
aluminum oxide tri-hydrate. When the aluminum oxide mono-hydrate is
in the form of gel, the gel may be peptized by water or acidic
water. When alumina is synthesized by a precipitation method, a
source of acidic aluminum may be selected from aluminium chloride,
aluminium sulfate, aluminium nitrate, and the like, and a source of
basic aluminum may be selected from sodium aluminate, potassium
aluminate, and the like.
[0064] The blending amount of the binder is preferably 5 to 70 wt
%, and particularly preferably 10 to 60 wt % of the total amount of
the composite oxide and the binder constituting the catalyst. If
the amount is less than 5 wt %, the mechanical strength of the
catalyst tends to decrease; and if more than 70 wt %, hydrocracking
activity and selectivity may decrease on the whole. When the USY
zeolite is used as a composite oxide, the amount of the USY zeolite
is preferably 1 to 80 wt % of the total amount of the composite
oxide and the binder forming the catalyst, and particularly
preferably 10 to 70 wt %. If the amount is less than 1 wt %, the
effect of increase in the hydrocracking activity on basis of the
use of the USY zeolite is hardly exhibited; and if more than 80 wt
%, the middle distillate selectivity relatively decreases.
[Metal Component]
[0065] The hydrocracking catalyst of the present invention contains
a metal selected from Group VI and Group VIII of the periodic table
as an active component. Among the metals of Group VI and Group
VIII, molybdenum, tungsten, iron, ruthenium, osmium, cobalt,
rhodium, iridium, nickel, palladium, and platinum are particularly
preferably used. The metals may be used alone or in combination of
two ore more. The metals is preferably added at an amount so that
the total amount of the metals of Group VI and Group VIII is
preferably 0.05 to 35 wt % of the hydrocracking catalyst, and
particularly preferably 0.1 to 30 wt %. When molybdenum is used as
a metal, the molybdenum content in the hydrocracking catalyst is
preferably 5 to 20 wt %, and particularly preferably 7 to 15 wt %.
When tungsten is used as a metal, the tungsten content in the
hydrocracking catalyst is preferably 5 to 30 wt %, and particularly
preferably 7 to 25 wt %. The amount of molybdenum or tungsten less
than the above-mentioned range is undesirable, because the
hydrogenation function of the active metal required for the
hydrocracking reaction is insufficient. If the amount of molybdenum
or tungsten is more than the above-mentioned range, on the other
hand, the active metal component unpreferably tends to easily
aggregate.
[0066] When molybdenum or tungsten is used as the metal, further
addition of cobalt or nickel may more preferably increase the
hydrogenation function of the active metal. In this instance, the
total amount of cobalt or nickel is preferably 0.5 to 10 wt % in
the hydrocracking catalyst, and particularly preferably 1 to 7 wt
%. When using one or more of the metals among rhodium, iridium,
platinum, and palladium, the content of these metals is preferably
0.1 to 5 wt %, and particularly preferably 0.2 to 3 wt %. If the
amount is less than the above range, sufficient hydrogenation
function cannot be obtained. If the amount is more than the above
range, unpreferably the addition efficiency becomes worse,
resulting in uneconomical.
[0067] The Group VI metal component to be supported on the carrier
as an active ingredient may be added by impregnating the carrier
with an aqueous solution of a compound such as ammonium
paramolybdate, molybdic acid, ammonium molybdate, molybdophosphoric
acid, ammonium tungstate, tungstic acid, tungstic anhydride, and
tungstophosphoric acid.
[0068] As the Group VIII metal component, an aqueous solution of a
compound such as nitrate, sulfate, chloride, fluoride, bromide,
acetate, carbonate, or phosphate of nickel or cobalt; or an aqueous
solution of a compound such as chloroplatinic acid,
dichlorotetraammine platinum, tetrachlorohexammine platinum,
platinum chloride, platinum iodonium, potassium chloroplatinate,
palladium acetate, palladium chloride, palladium nitriate,
palladium acetylacetonate, rhodium acetate, rhodium chloride,
rhodium nitrate, ruthenium chloride, osmium chloride, iridium
chloride, and the like may be used.
[0069] Furthermore, phosphorus, boron, potassium and a rare earth
such as lanthanum, cerium, ytterbium, europium, and dysprosium may
be added as a third component.
[Production Method of Hydrocracking Catalyst]
[0070] The hydrocracking catalyst of the present invention can be
prepared by forming the carrier from the composite oxide and the
binder by kneading, forming the resultant mixture, then drying and
calcining the formed mixture, and impregnating the carrier with an
aqueous solution of a metal component, followed by drying and
calcining. The method of preparing the hydrocracking catalyst of
the present invention will be described below, but the method is
not limited to the following method. Other methods which can
prepare the catalyst possessing the specified pore characteristics
and performance may also be used.
[0071] Any kneader generally used for catalyst preparation can be
used for the above kneading. In general, a method of charging
feeds, adding water, and stirring the mixture with stirring blades
is suitably used. The addition order of the feeds and additives and
the like are not particularly limited. Water is added during
kneading, but the water does not need to add when the feed is a
slurry. An organic solvent such as ethanol, isopropanol, acetone,
methyl ethyl ketone, methyl isobutyl ketone or the like may be
added in addition to or instead of water. The kneading temperature
and the kneading time may vary depending on the composite oxides
and binders used as feeds. There are no particular limitations to
the temperature and kneading time insofar as a desired pore
structure can be obtained. In a similar way, other components, for
example, an acid such as nitric acid, a base such as ammonia, an
organic compound such as citric acid and ethylene glycol, a water
soluble high molecular compound such as cellulose ethers and
polyvinyl alcohol, ceramic fiber, and the like may be added and
kneaded to the extent that the properties of the catalyst of the
present invention are maintained.
[0072] After kneading, the kneaded materials may be formed by a
forming method commonly used in catalyst preparation. In
particular, the extrusion molding using a screw extruder which can
efficiently form the catalyst into any form such as pellets
(cylindrical pellets, particular shaped pellets), granules,
spheres, and the like, and the oil drop method which can
efficiently form into a sphere may be preferably used. Although
there are no particular limitations to the size of the formed
product, for example, cylindrical pellets with a diameter of 0.5 to
20 mm and a length of 0.5 to 15 mm may be easily obtained.
[0073] The formed product obtained in this manner is dried and
calcined to obtain a carrier. The calcining may be carried out in a
gas atmosphere such as air or nitrogen at a temperature of 300 to
900.degree. C. for 0.1 to 20 hours.
[0074] There are no particular limitations to the method for
supporting the metal component on the carrier. An aqueous solution
of the oxide or its salt of the metal to be supported such as a
nitrate, an acetate, a carbonate, a phosphate, or a halide is
prepared, and the metal component is supported by a spray method,
an impregnation method by immersing, an ion-exchange method, and
the like. More metal component may be supported by repeating the
supporting and drying treatments.
[0075] For example, after impregnating the carrier with an aqueous
solution containing the Group VI metal component, the carrier is
dried at a temperature from room temperature to 150.degree. C., and
preferably 100 to 130.degree. C. for 0.5 hours or more, or the
carrier as is without drying may be successively impregnated with
an aqueous solution containing the Group VIII metal component, then
dried at a temperature from room temperature to 150.degree. C., and
preferably 100 to 130.degree. C. for 0.5 hours or more, followed by
calcining at 350 to 800.degree. C., and preferably 450 to
600.degree. C. for 0.5 hours or more, to obtain a catalyst.
[0076] The metal of Group VI or Group VIII supported in the
catalyst of the invention may be any form such as a metal, an
oxide, a sulfide, or the like.
[Mechanical Strength of Hydrocracking Catalyst and Carrier]
[0077] The stronger mechanical strength of the hydrocracking
catalyst is, the more preferable the catalyst become. For example,
a cylindrical pellet with a diameter of 1.6 mm has side crush
strength preferably of 3 kg or more, and more preferably 4 kg or
more. When preparing the catalyst by supporting the metal component
on the formed carrier by impregnation, it is desirable that the
formed carrier itself have sufficient mechanical strength in order
to produce the catalyst with a high yield. Specifically, as a
mechanical strength of the formed carrier in the present invention,
a cylindrical pellet with a diameter of 1.6 mm has similarly
preferably 3 kg or more of side crush strength, and more preferably
4 kg or more.
[0078] The bulk density of the catalyst is preferably 0.4 to 2.0
g/cm.sup.3, more preferably 0.5 to 1.5 g/cm.sup.3, and particularly
preferably 0.6 to 1.2 g/cm.sup.3.
[Properties of Hydrocracked Oil]
[0079] In the hydrocracking step, 40 vol % or more of the fractions
having a boiling point of 215.degree. C. or more in the hydrocarbon
feedstocks are converted into fractions having a boiling point of
less than 215.degree. C. The content of the fractions having a
boiling point of not more than 215.degree. C., that is, hydrocarbon
lighter than naphthalene, in the hydrocracked oil is 40 vol % or
more, preferably 50 vol % or more, more preferably 60 vol % or
more, and particularly preferably 75 vol % or more. The content of
monocyclic aromatic hydrocarbons (alkylbenzenes) in the
hydrocracked oil obtained by the hydrocracking is preferably 30 vol
% or more, more preferably 35 vol % or more, and still more
preferably 40 vol % or more; the content of 1.5-cyclic aromatic
hydrocarbons is preferably 30 vol % or less, and more preferably 28
vol % or less; and the content of polycyclic aromatic hydrocarbons
is preferably 10 vol % or less, more preferably 7 vol % or less,
and still more preferably 5 vol % or less.
[0080] Furthermore, the ratio of the aromatic ring-constituting
carbon ratio of the hydrocracked oil to the aromatic
ring-constituting carbon ratio of the feed (aromatic ring carbon
remaining ratio) is 0.5 or more, more preferably 0.6 or more, and
particularly preferably 0.7 or more. If aromatic ring carbon
remaining ratio is smaller than 0.5, it is undesirable that the
cracking reaction is excessively progress, which results in coking
and reduces the catalyst life.
[Post-Treatment Step]
[0081] A post-treatment step similar to the pre-treatment step may
be provided in the method of the present invention as required in
order to refine the hydrocracked oil obtained by hydrocracking.
Although there are no particular limitations to the post-treatment
step, the kind and amount of the catalyst and operating conditions
as applied to the pre-treatment step can be applied to the
post-treatment step. The post-treatment step may be installed
immediately after the hydrocracking step to process the
hydrocracked oil, or may be installed after a separation step to
separately process each hydrocarbon fraction obtained in the
separation step. It is possible to significantly reduce impurities
in the product by installing the post-treatment step. For example,
the sulfur content and nitrogen content may be reduced to 0.1 ppm
by weight or less.
[Separation Method of Hydrocracked Oil]
[0082] The obtained hydrocracked oil may be separated into products
such as an LPG fraction, a gasoline fraction, a kerosene fraction,
a gas oil fraction, a non-aromatic naphtha fraction, and monocyclic
aromatic hydrocarbons by an appropriate separation step. Although
these fractions as is may be used as LPG, gasoline, kerosene, gas
oil or feed for petrochemicals if the petroleum product
specification is satisfied, usually these fractions may be used as
stocks for producing these petroleum products through blending or
refining. There are no particular limitations to the separation
process. Any generally known methods such as precision
distillation, adsorption separation, sorption separation,
extraction separation, membrane separation, and the like may be
adopted according to the product properties. The operating
conditions thereof may be appropriately selected.
[0083] Distillation is a widely-used method, which separates a
hydrocracked product oil into, for example, an LPG fraction, a
gasoline fraction, a kerosene fraction, and a gas oil fraction by
utilizing the difference of boiling point. Specifically, an LPG
fraction which is a lighter fraction than a boiling point of around
0 to 30.degree. C.; a gasoline fraction having a boiling point
higher than the LPG fraction up to around 150 to 215.degree. C.; a
kerosene fraction having a boiling point higher than the gasoline
fraction up to around 215 to 260.degree. C.; and a gas oil fraction
having a boiling point higher than the kerosene fraction up to
around 260 to 370.degree. C. can be obtained from the hydrocracked
product oil. The factions heavier than the gas oil fraction may be
recycled as an unreacted product to be treated again in the
hydrocracking step or may be used as a blending stock for fuel oil
A and the like.
[0084] The extraction method of separating aromatics, which can
separate into aromatic component and non-aromatics component using
an appropriate solvent, may be used by appropriately combining with
the above distillation method. In this case, a gasoline fraction
and/or a kerosene fraction obtained by distillation are mixed with
a solvent such as sulforane (tetrahydrothiophene dioxide) which
selectively extracts aromatics. The mixture is separated into an
extract fraction in which aromatic compounds are selectively
extracted with sulforane and a raffinate fraction in which paraffin
hydrocarbons which are not extracted with sulforane are
concentrated, by treating the mixture under extraction conditions
of a temperature of 20 to 100.degree. C. and a pressure of from
normal pressure to 1.0 MPa. Since the extract fraction containing
components having a boiling point of at least 80.degree. C. or
higher obtained by the extraction treatment contains selectively
extracted aromatic compounds, this fraction may be used for product
as an aromatic stock after hydrorefining if necessary. Since the
raffinate fraction contains a relatively large amount of
isoparaffins and naphthens, the fraction as is may be used as a
gasoline blending stock for producing a high octane gasoline
composition, further may be used as a feed for a catalytic
reforming and converted into aromatic hydrocarbons.
[0085] The aromatic components and sulforane in the extract
fraction which is extracted with sulforane may be easily separated
by distillation. The separated sulforane may be used again as an
extraction solvent. The separated aromatic components may be
converted into paraxylene, benzene, and the like having a higher
valuable via transalkylation, isomerization, and the like.
[Product Hydrocarbons]
[0086] As examples of the hydrocarbon products obtained through the
above-mentioned separation methods, an LPG fraction with a boiling
point of -10 to 30.degree. C., a gasoline fraction with a boiling
point of 30 to 215.degree. C., a kerosene fraction with a boiling
point of 215 to 260.degree. C., a gas oil fraction with a boiling
point of 260 to 370.degree. C., and a residue remaining after
separation of these fractions can be given. In the present
invention, the smaller the amount of the residue the better. The
residue may be lightened by recycling to the hydrocracking step
again.
[0087] It is also possible to extract the gasoline fraction with a
solvent such as sulforane to obtain an extract fraction and a
raffinate fraction. The raffinate fraction is a non-aromatic
naphtha fraction and is useful as a gasoline stock, a feed of a
solvent, and the like. The extract fraction is useful monocyclic
aromatic hydrocarbons (alkylbenzenes) as a feed for
petrochemicals.
Example
[0088] The method for producing hydrocarbon fractions of the
present invention will be explained in detail and specifically by
way of Examples and Comparative Examples below.
[Preparation of Hydrocracking Catalyst]
[0089] 1078 g of USY-type zeolite (HSZ-350HUA manufactured by Tosoh
Corp.) having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 10.5, a lattice
constant of 2.439 nm, and a specific surface area of 650 m.sup.2/g
was mixed with 1303 g of alumina powder (Pural SB manufactured by
SASOL Corp.), and 500 mL of 4.0 wt % nitric acid solution, and 875
g of ion exchanged water were added. The mixture was kneaded,
extruded into the form of trilobe pellets, dried at 130.degree. C.
for six hours, and calcined at 600.degree. C. for six hours to
obtain a carrier.
[0090] The carrier was impregnated with an aqueous solution of
ammonium molybdate by spraying, dried at 130.degree. C. for six
hours, impregnated with an aqueous solution of nickel nitrate by
spraying, dried at 130.degree. C. for six hours, and calcined at
500.degree. C. for 30 minutes in an air stream to obtain a catalyst
A. The composition (supported metal content) and typical properties
of the catalyst A are shown in Table 4.
[0091] The pore characteristics of the catalyst A were measured
using the nitrogen gas adsorption method to find that the specific
surface area was 387 m.sup.2/g, the pore volume occupied by pores
with a diameter of 2 to 60 nm was 0.543 mL/g, and the median pore
diameter was 9.6 nm. The catalyst A had a stable diameter of 1.2
mm, an average length of 4.0 mm, an average side crush strength of
12.0 kg, and a bulk density of 0.668 g/cm.sup.3. The stable
diameter refers to the height of pellets when fixed to a flat
board.
[0092] The following devices and methods were used for measuring
the catalyst properties.
[Method of Measuring Pore Characteristics]
[0093] ASAP 2400 manufactured by Micromeritics was used for
measuring the pore characteristics (specific surface area, pore
volume occupied by pores with a diameter of 2 to 60 nm, and median
pore diameter) by the nitrogen gas adsorption method.
[Method of Measuring Average Side Crush Strength]
[0094] The side crush strength of trilobe samples was measured
using a tablet breaking-strength meter, TH-203CP manufactured by
Toyama Sangyo Co., Ltd. A round measuring probe with a tip diameter
of 5 mm was used. The measuring probe was abutted to and pressed
the center of the cylindrical sample to measure the pressure when
the sample was broken. The average side crush strength was
determined by averaging the results of measurement of 20 randomly
selected samples.
Example 1
[0095] A light fraction (feed A) prepared by fractionating a light
cycle oil (LCO) into two fractions at 240.degree. C. was used for a
hydrocracking reaction using the catalyst A under a reaction
pressure of 3.0 MPa, LHSV of 1.0 h.sup.-1, hydrogen/oil ratio of
1,400 NL/L, and a reaction temperature of 380.degree. C. The
properties of the feed A are shown in Table 1 and the properties of
the product oil are shown in Table 2. In Table 2, the conversion
rate of 215.degree. C. or higher fractions is a value obtained by
the following equation.
Conversion rate of 215.degree. C. or higher fractions
(%)=100-215.degree. C. or higher fractions in product oil (vol
%)/215.degree. C. or higher fractions in feed (vol %).times.100
[0096] The ratio of the aromatic ring-constituting carbon ratio of
the hydrocracked oil to the aromatic ring-constituting carbon ratio
of the feed (aromatic ring carbon remaining ratio) is also shown in
Table 2. The reaction liquid yield is the residual ratio (wt %) of
the fractions with 5 or more carbon numbers after the reaction.
Example 2
[0097] The hydrocracking reaction was carried out under the same
conditions as in Example 1 except for the reaction temperature of
400.degree. C. The properties of the product oil obtained by the
reaction are shown in Table 2.
Example 3
[0098] The hydrocracking reaction was carried out under the same
conditions as in Example 1 except for the LHSV of 0.5 h.sup.-1. The
properties of the product oil obtained by the reaction are shown in
Table 2.
Example 4
[0099] A hydrocracking reaction was carried out using a feed C (a
mixture of 30 vol % of 1-methylnaphthalene, 30 vol % of o-xylene,
and 40 vol % of normal dodecane) having properties shown in Table 1
and the catalyst A as the hydrocracking catalyst under a reaction
pressure of 3.0 MPa, LHSV of 1.0 h.sup.-1, hydrogen/oil ratio of
683 NL/L, and a reaction temperature of 380.degree. C. The
properties of the product oil obtained by the reaction are shown in
Table 2.
Example 5
[0100] The hydrocracking reaction was carried out under the same
conditions as in Example 4 except for the LHSV of 0.3 h.sup.-1. The
properties of the product oil obtained by the reaction are shown in
Table 2.
Comparative Example 1
[0101] The hydrocracking reaction was carried out under the same
conditions as in Example 1 except for using a feed B (light cycle
oil: LCO) having the properties shown in Table 1. The properties of
the product oil obtained by the reaction are shown in Table 2.
Comparative Example 2
[0102] The hydrocracking reaction was carried out under the same
conditions as in Example 2 except for using a feed B (light cycle
oil: LCO) having the properties shown in Table 1. The properties of
the product oil obtained by the reaction are shown in Table 2.
Comparative Example 3
[0103] The hydrocracking reaction was carried out under the same
conditions as in Example 3 except for using a feed B (light cycle
oil: LCO) having the properties shown in Table 1. The properties of
the product oil obtained by the reaction are shown in Table 2.
Comparative Example 4
[0104] The hydrocracking reaction was carried out under the same
conditions as in Example 4 except for the reaction pressure of 1.0
MPa. The properties of the product oil obtained by the reaction are
shown in Table 2.
Comparative Example 5
[0105] A reaction was carried out using a feed D (vacuum gas oil of
Middle East crude oil: VGO) having properties shown in Table 1 and
the catalyst A under a reaction pressure of 4.0 MPa, LHSV of 0.3
h.sup.-1, a hydrogen/oil ratio of 400 NL/L, and a reaction
temperature of 388.degree. C. The properties of the product oil
obtained by the reaction are shown in Table 2.
[0106] The hydrocracked oils obtained in Examples 1 to 3 and
Comparative Example 5 were separated into an LPG fraction
(30.degree. C. or lower), a gasoline fraction (30 to 215.degree.
C.), a kerosene fraction (215 to 260.degree. C.), a gas oil
fraction (260 to 370.degree. C.), and a residue by distillation.
The yield (vol %) of each fraction of each product oil is shown in
Table 3.
TABLE-US-00001 TABLE 1 Feed A Feed B Feed C Feed D Density
g/cm.sup.3 0.9018 0.9136 0.8688 0.9357 Sulfur content wt ppm 580
1380 2270 23890 Nitrogen content wt ppm 143 260 3.5 1210 Bromine
number g-Br.sub.2/100 g 5 4 0.0 5.0 Total aromatic hydrocarbons vol
% 72.2 70.9 60.0 51.7 Monocyclic aromatic hydrocarbons vol % 15.1
10.4 30.0 7.3 1.5-Cyclic aromatic hydrocarbons vol % 21.7 17.0 0
13.2 Bicyclic aromatic hydrocarbons vol % 35.5 37.4 30.0 18.1 Tri-
or larger polycyclic aromatic hydrocarbons vol % 0 6.0 0 13.1
Aromatic ring-constituting carbon ratio mol % 52.9 52.6 45.7 31.6
Distillation Initial boiling point (IBP) .degree. C. 143 146.5 140
196 properties 10 vol % Distillate temperature .degree. C. 200.5
206.0 145 319 90 vol % Distillate temperature .degree. C. 272.5
315.50 240 533 End point (EP) .degree. C. 286.0 355.5 250 601
215.degree. C. or higher fractions vol % 73.0 80.0 70 99
TABLE-US-00002 TABLE 2 Example Comparative Example 1 2 3 4 5 1 2 3
4 5 Feed A A A C C B B B C D Hydrocracking catalyst A A A A A A A A
A A Reaction temperature .degree. C. 380 400 380 380 380 380 400
380 380 388 Reaction pressure MPa 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
1.0 4.0 LHSV h.sup.-1 1.0 1.0 0.5 1.0 0.3 1.0 1.0 0.5 1.0 0.3
Hydrogen/oil ratio NL/L 1400 1400 1400 683 683 1400 1400 1400 683
400 Reaction solution yield wt % 86 80 84 91 70 89 87 90 98 87
Sulfur content wt ppm 2 2 0.8 22 7 4 6 4 32 100 Nitrogen content wt
ppm <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
<0.5 29 Distil- 10 vol % Distillate temperature .degree. C. 78.5
88.5 85.5 30.0 <30.0 125.5 125.5 126.5 146.0 229.5 lation 50 vol
% Distillate temperature .degree. C. 166.0 173.0 171.5 164.0 85.0
218.0 219.5 226.0 198.0 375.0 properties 90 vol % Distillate
temperature .degree. C. 245.0 254.5 253.0 230.0 157.0 304.0 307.5
310.0 239.0 495.0 Conversion rate of 215.degree. C. or higher %
69.9 63.0 64.4 52.2 90.3 35.0 33.8 30.0 2.2 7.5 fractions
Monocyclic aromatic hydrocarbons vol % 31.0 38.7 39.0 43.0 52.0
16.9 25.0 24.3 26.5 6.8 Benzene vol % 1.2 1.6 1.5 1.9 5.3 0.7 1.0
0.9 0.2 0 Toluene vol % 6.0 7.1 7.0 9.0 21.2 3.3 4.3 3.8 0.5 0
Xylenes vol % 8.2 8.2 8.7 23.7 20.5 4.8 5.2 4.9 24.9 0 Ortho vol %
2.1 2.0 2.1 5.9 4.7 1.4 1.3 1.3 19.5 0 Meth vol % 4.3 4.3 4.6 12.8
11.0 2.4 2.7 2.5 4.8 0 Para vol % 1.8 1.9 2.0 5.0 4.8 1.0 1.2 1.1
0.6 0 Ethyl benzene vol % 1.8 1.7 1.8 0.5 0 0.6 1.1 1.0 0 0
1.5-Cyclic aromatic hydrocarbons vol % 27.4 22.0 18.3 7.8 0.0 33.7
26.1 27.9 27.9 18.8 Bicyclic aromatic hydrocarbons vol % 8.6 6.8
4.1 0.3 0.0 16.1 13.1 10.3 9.3 13.8 Tri- or larger polycyclic
aromatic vol % 0.3 1.2 0.9 0.0 0.0 1.8 2.3 0.8 0.0 5.9 hydrocarbons
Aromatic ring-constituting carbon ratio mol % 43.6 47.1 43.4 36.9
42.2 46.1 48.5 42.9 43.6 13.7 Aromatic ring carbon remaining ratio
-- 0.82 0.89 0.82 0.81 0.92 0.87 0.92 0.82 0.95 0.43
TABLE-US-00003 TABLE 3 Exam- Comparative Example 1 Example 2 ple 3
Example 5 LPG fraction vol % 27 31 27 13 Gasoline fraction vol % 65
58 60 8 Kerosene fraction vol % 14 16 15 10 Gas oil fraction vol %
5 6 7 32 Residue vol % 1 1 1 51 Total vol % 112 112 110 114
[0107] As shown by Examples 1 to 3 in Table 2, it has been
confirmed that as compared with the case of using vacuum gas oil
which has been widely used as a feed for a hydrocracking reaction
(Comparative Example 5), by hydrocracking using hydrocarbon
feedstocks having a suitable aromatic ring-constituting carbon
ratio and a suitable boiling point range under suitable
hydrocracking reaction conditions, target monocyclic aromatic
hydrocarbons (alkylbenzenes), particularly BTX fractions such as
higher valuable benzene and toluene can be obtained at a high
yield. In addition, it can be also understood from Table 3 showing
the yield of each fraction obtained from the hydrocracked oils that
a higher valuable gasoline fraction can be produced at a high
yield, while coproducing an LPG fraction, a gasoline fraction, and
kerosene and gas oil fractions and reducing impurities such as
sulfur and nitrogen components.
Examples 6 to 10
[0108] 1,036 g of H--Y-type zeolite (HSZ-350HSA manufactured by
Tosoh Corp.) having an SiO.sub.2/Al.sub.2O.sub.3 ratio of 5.6, a
lattice constant of 2.45 nm, and a specific surface area of 650
m.sup.2/g was mixed with 1,390 g of alumina powder (Versal 250 by
UOP Corp.), and 652 mL of 4.0 wt % nitric acid solution and 163 g
of ion exchanged water were added. The mixture was kneaded,
extruded into the form of trilobe pellets, dried at 130.degree. C.
for six hours, and calcined at 600.degree. C. for one hour to
obtain a carrier.
[0109] The carrier was impregnated with an aqueous solution of
ammonium molybdate by spraying, dried at 130.degree. C. for six
hours, impregnated with an aqueous solution of nickel nitrate by
spraying, dried at 130.degree. C. for six hours, and calcined at
500.degree. C. for 30 minutes in an air stream to obtain a catalyst
B. Properties of catalyst B are shown in Table 4.
[0110] Hydrocracking of the feed C was carried out using the
catalyst B instead of the catalyst A under the operation conditions
shown in the upper part of Table 5 (Examples 6 to 10). The liquid
yield and properties of the product oil are shown in Table 5.
Examples 11 to 15
[0111] A catalyst C was prepared in the same manner as the catalyst
B, except for using 1,202 g of NH.sub.4--Y type zeolite (HSZ-341NHA
manufactured by Tosoh Corp.) having an SiO.sub.2/Al.sub.2O.sub.3
ratio of 6.9, a lattice constant of 2.452 nm, and a specific
surface area of 700 m.sup.2/g and 1,202 g of alumina powder (Versal
250 manufactured by UOP Corp.). Properties of the catalyst C are
shown in Table 4.
[0112] Hydrocracking of Examples 11 to 15 was carried out under the
same conditions as in Examples 6 to 10, except for using the
catalyst C instead of the catalyst B as shown in the upper part of
Table 5. The liquid yield and properties of the product oil are
shown in Table 5.
Examples 16 to 19
[0113] A catalyst D was prepared in the same manner as the catalyst
C, except for using 1,684 g of NH.sub.4-Y type zeolite (HSZ-341NHA
manufactured by Tosoh Corp.), 834 g of alumina powder (Versal 250
manufactured by UOP Corp.), 500 mL of 4.0 wt % nitric acid
solution, and 50 g of ion-exchanged water. Properties of catalyst D
are shown in Table 4.
[0114] Hydrocracking of Examples 16 to 19 was carried out under the
same conditions as in Examples 6 to 9, except for using the
catalyst D instead of the catalyst B as shown in the upper part of
Table 6. The properties of the product oil are shown in Table
6.
Examples 20 to 24
[0115] A catalyst E was prepared in the same manner as the catalyst
B, except for using 1,719 g of NH.sub.4-.beta. type zeolite (CP814E
manufactured by Zeolyst International) having an
SiO.sub.2/Al.sub.2O.sub.3 ratio of 23.6 and a specific surface area
of 680 m.sup.2/g, 834 g of alumina powder (Versal 250 manufactured
by UOP Corp.), 500 mL of 4.0 wt % nitric acid solution, and 100 g
of ion-exchanged water. Properties of catalyst E are shown in Table
4.
[0116] Hydrocracking of Examples 20 to 24 was carried out under the
same conditions as in Examples 6 to 10, except for using the
catalyst E instead of the catalyst B as shown in the upper part of
Table 6. The properties and the like of the product oil are shown
in Table 6.
Examples 25 to 29
[0117] A catalyst F was prepared in the same manner as the catalyst
B, except for using 1,000 g of H-.beta. type zeolite (HSZ-940 HOA
manufactured by Tosoh Corp.) having an SiO.sub.2/Al.sub.2O.sub.3
ratio of 36.9 and a specific surface area of 450 m.sup.2/g and
1,390 g of alumina powder (Versal 250 manufactured by UOP Corp.).
Properties of catalyst F are shown in Table 4.
[0118] Hydrocracking of Examples 25 to 29 was carried out under the
same conditions as in Examples 6 to 10, except for using the
catalyst F instead of the catalyst B as shown in the upper part of
Table 7. The properties and the like of the product oil are shown
in Table 7.
Examples 30 to 34
[0119] A catalyst G was prepared in the same manner as the catalyst
F, except for using 1,400 g of H-.beta. type zeolite (HSZ-940 HOA
manufactured by Tosoh Corp.), 834 g of alumina powder (Versal 250
manufactured by UOP Corp.), 500 mL of 4.0 wt % nitric acid
solution, and 100 g of ion-exchanged water. Properties of catalyst
G are shown in Table 4.
[0120] Hydrocracking of Examples 30 to 34 was carried out under the
same conditions as in Examples 6 to 10, except for using the
catalyst G instead of the catalyst B as shown in the upper part of
Table 7. The properties and the like of the product oil are shown
in Table 7.
Examples 35 to 39
[0121] A catalyst H was prepared in the same manner as the catalyst
B, except for using 1,533 g of NH.sub.4-ZSM-5 zeolite (CBV3020E
manufactured by Zeolyst International) having an
SiO.sub.2/Al.sub.2O.sub.3 ratio of 30.6 and a specific surface area
of 400 m.sup.2/g, 834 g of alumina powder (Versal 250 manufactured
by UOP Corp.), 500 mL of 4.0 wt % nitric acid solution, and 100 g
of ion-exchanged water. Properties of catalyst H are shown in Table
4.
[0122] Hydrocracking of Examples 35 to 39 was carried out under the
same conditions as in Examples 6 to 10, except for using the
catalyst H instead of the catalyst B as shown in the upper part of
Table 8. The properties and the like of the product oil are shown
in Table 8.
Examples 40 to 44
[0123] A catalyst I was prepared in the same manner as the catalyst
C, except for using a cobalt nitrate aqueous solution instead of a
nickel nitrate aqueous solution.
[0124] Properties of catalyst I are shown in Table 4.
[0125] Hydrocracking of Examples 40 to 44 was carried out under the
same conditions as in Examples 6 to 10, except for using the
catalyst I instead of the catalyst B as shown in the upper part of
Table 8. The properties and the like of the product oil are shown
in Table 8.
Comparative Examples 6 to 10
[0126] 2,000 g of alumina powder (Pural SB manufactured by SASOL
Corp.) was mixed with 363 g of boric acid (manufactured by Kanto
Chemical Co., Inc.), and 1,000 mL of 3.0 wt % nitric acid solution
and 250 g of ion exchanged water were added. The mixture was
kneaded, extruded into cylindrical pellets, dried at 130.degree. C.
for six hours, and calcined at 600.degree. C. for one hour to
obtain a carrier.
[0127] The carrier was impregnated with an aqueous solution of
ammonium molybdate by spraying, dried at 130.degree. C. for six
hours, impregnated with an aqueous solution of cobalt nitrate by
spraying, dried at 130.degree. C. for six hours, and calcined at
500.degree. C. for 30 minutes in an air stream to obtain a catalyst
J. Properties of catalyst J are shown in Table 4.
[0128] Hydrocracking of Comparative Examples 6 to 10 was carried
out under the same conditions as in Examples 6 to 10, except for
using the catalyst J instead of the catalyst A as shown in the
upper part of Table 9, and the reaction temperature in Comparative
Examples 6 to 8 was respectively 320.degree. C., 350.degree. C.,
and 380.degree. C. The liquid yield and properties of the product
oil are shown in Table 9.
TABLE-US-00004 TABLE 4 Catalyst A B C D E F G H I J Hydro- Carri-
Zeolite HSZ- HSZ- HSZ- HSZ- CP814E 940HOA 940HOA CBV HSZ- --
cracking er 350HUA 330HSA 341NHA 341NHA 3020E 341NHA catalyst
SiO.sub.2/ mol 10.5 5.6 6.9 6.9 23.6 39.6 39.6 30.6 6.9 --
Al.sub.2O.sub.3 Amount wt % 50 50 50 70 70 50 70 70 50 -- Alumina
Pural Versal Versal Versal Versal Versal Versal Versal Versal Pural
SB 250 250 250 250 250 250 250 250 SB Amount wt % 50 50 50 30 30 50
30 30 50 100 Si wt % 15.8 13.8 14.5 19.9 26.3 17.8 26.6 26.9 15.0 0
Al wt % 23.5 24.0 24.7 17.3 14.5 21.1 13.4 13.9 24.7 34.8 Na wt %
0.01 0.09 0.03 0.05 0.01 0.02 0.03 0.03 0.03 <0.01 Mo wt % 7.1
7.2 7.4 7.7 7.1 7.4 7.8 7.6 9.7 10.2 Ni wt % 3.0 2.8 2.8 2.8 3.0
2.8 3.0 3.0 -- -- Co wt % -- -- -- -- -- -- -- -- 3.1 3.2 Specific
surface m.sup.2/g 387 396 438 493 402 335 359 280 410 218 area Pore
volume cc/g 0.543 0.437 0.470 0.401 0.671 0.407 1.312 0.279 0.447
0.460 Median pore nm 9.6 6.3 6.1 4.0 12.9 6.6 4.1 5.9 6.0 7.8
diameter
TABLE-US-00005 TABLE 5 Example 6 7 8 9 10 11 12 13 14 15 Feed C C C
C C C C C C C Hydrocracking catalyst B B B B B C C C C C Reaction
temperature .degree. C. 300 320 350 350 350 300 320 350 350 350
Reaction pressure MPa 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 LHSV
h.sup.-1 1.0 1.0 1.0 1.5 0.5 1.0 1.0 1.0 1.5 0.5 Hydrogen/oil ratio
NL/L 1365 1365 1365 1365 1365 1365 1365 1365 1365 1365 Reaction
solution yield wt % 98 99 93 96 81 96 98 89 93 65 Sulfur content wt
ppm 6 4 3 2 3 2 1 0.8 0.4 3 Nitrogen content wt ppm <0.5 <0.5
<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
Distil- 10 vol % Distillate temperature .degree. C. 139.0 138.0
74.0 110.0 <30.0 139.0 110.0 <30.0 85.0 <30.0 lation 50
vol % Distillate temperature .degree. C. 208.0 208.0 199.0 207.0
137.0 208.0 206.0 144.0 203.0 66.0 properties 90 vol % Distillate
temperature .degree. C. 217.0 217.0 216.0 216.0 212.0 216.0 217.0
214.0 216.0 169.0 Conversion rate of 215.degree. C. or higher % 46
41 59 65 81 65 51 76 68 100 fractions Monocyclic aromatic
hydrocarbons vol % 35.4 36.4 41.3 38.9 41.3 39.8 40.3 40.6 40.4
36.4 Benzene vol % 0.3 0.5 1.3 0.8 2.6 0.4 0.8 2.0 1.3 3.2 Toluene
vol % 1.6 2.6 6.3 3.8 12.6 2.6 4.0 9.1 5.9 13.6 Xylenes vol % 27.7
25.7 25.4 27.9 18.1 27.1 26.5 21.5 26.3 14.4 Ortho vol % 15.0 11.6
8.3 13.6 4.1 12.5 10.6 6.1 12.1 3.2 Meth vol % 10.9 11.6 13.0 11.6
9.9 12.2 12.7 11.4 11.3 7.8 Para vol % 1.8 2.5 4.1 2.7 4.1 2.4 3.2
4.0 2.9 3.4 Ethyl benzene vol % 0 0.1 0.3 0.1 0.5 0.1 0.1 0.4 0.3 0
1.5-Cyclic aromatic hydrocarbons vol % 13.2 16.2 11.4 15.8 5.4 14.0
12.3 8.2 12.7 0 Bicyclic aromatic hydrocarbons vol % 0.3 0.3 0.2
0.6 0 0.2 1.0 0.6 0.4 0 Tri- or larger polycyclic aromatic vol % 0
0 0 0 0 0 0 0 0 0 hydrocarbons Aromatic ring-constituting carbon
ratio mol % 30.5 34.0 34.5 36.0 35.6 34.7 33.2 34.2 34.4 36.6
Aromatic ring carbon remaining ratio -- 0.67 0.74 0.76 0.79 0.78
0.76 0.73 0.75 0.75 0.80
TABLE-US-00006 TABLE 6 Example 16 17 18 19 20 21 22 23 24 Feed C C
C C C C C C C Hydrocracking catalyst D D D D E E E E E Reaction
temperature .degree. C. 300 320 350 350 300 320 350 350 350
Reaction pressure MPa 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 LHSV
h.sup.-1 1.0 1.0 1.0 1.5 1.0 1.0 1.0 1.5 0.5 Hydrogen/oil ratio
NL/L 1365 1365 1365 1365 1365 1365 1365 1365 1365 Reaction solution
yield wt % 90 91 83 91 97 77 69 75 65 Sulfur content wt ppm 3 2 2
0.8 3 3 6 7 2 Nitrogen content wt ppm <0.5 <0.5 <0.5
<0.5 <0.5 <0.5 <0.5 <0.5 <0.5 Distillation 10 vol
% Distillate temperature .degree. C. 139.0 110.0 <30.0 34.0 59.0
<30.0 <30.0 <30.0 <30.0 properties 50 vol % Distillate
temperature .degree. C. 207.0 203.0 130.0 189.0 144.0 81.0 105.0
90.0 104.0 90 vol % Distillate temperature .degree. C. 217.0 216.0
214.0 216.0 220.0 143.0 166.0 164.0 165.0 Conversion rate of
215.degree. C. or higher fractions % 40 59 81 65 51 97 100 92 100
Monocyclic aromatic hydrocarbons vol % 38.1 41.9 40.3 41.9 39.7
50.1 68.5 50.2 69.6 Benzene vol % 0.5 1.2 2.7 1.7 0.7 2.9 3.2 2.3
4.0 Toluene vol % 2.9 5.6 12.7 7.9 1.8 10.9 17.1 9.2 21.0 Xylenes
vol % 25.2 25.6 17.3 24.0 31.0 27.0 26.7 30.6 27.6 Ortho vol % 10.6
8.1 3.9 8.4 13.0 6.1 6.1 7.5 6.2 Meth vol % 12.1 13.6 9.5 12.0 14.4
14.7 14.3 16.2 14.9 Para vol % 2.5 3.9 3.9 3.6 3.6 6.2 6.3 6.9 6.5
Ethyl benzene vol % 0.1 0.2 0.6 0.4 0.2 1.4 1.6 1.2 1.2 1.5-Cyclic
aromatic hydrocarbons vol % 13.6 7.3 2.8 7.7 22.5 2.2 0 4.7 0
Bicyclic aromatic hydrocarbons vol % 0.2 0 0 0.2 0.4 0 0 0.5 0 Tri-
or larger polycyclic aromatic hydrocarbons vol % 0 0 0 0 0 0 0 0 0
Aromatic ring-constituting carbon ratio mol % 32.1 31.3 32.9 33.3
43.8 53.3 65.4 55.4 64.1 Aromatic ring carbon remaining ratio --
0.70 0.68 0.72 0.73 0.96 1.17 1.43 1.21 1.40
TABLE-US-00007 TABLE 7 Example 25 26 27 28 29 30 31 32 33 34 Feed C
C C C C C C C C C Hydrocracking catalyst F F F F F G G G G G
Reaction temperature .degree. C. 300 320 350 350 350 300 320 350
350 350 Reaction pressure MPa 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
3.0 LHSV h.sup.-1 1.0 1.0 1.0 1.5 0.5 1.0 1.0 1.0 1.5 0.5
Hydrogen/oil ratio NL/L 1365 1365 1365 1365 1365 1365 1365 1365
1365 1365 Reaction solution yield wt % 94 86 77 73 63 99 82 76 74
74 Sulfur content wt ppm 2 2 0.6 0.5 3 2 2 3 2 1 Nitrogen content
wt ppm <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
<0.5 <0.5 <0.5 Distil- 10 vol % Distillate temperature
.degree. C. 83.0 <30.0 <30.0 <30.0 <30.0 109.0 <30.0
<30.0 <30.0 <30.0 lation 50 vol % Distillate temperature
.degree. C. 197.0 115.0 119.0 85.0 104.0 203.0 109.0 128.0 86.0
119.0 properties 90 vol % Distillate temperature .degree. C. 215.0
202.0 165.0 150.0 166.0 216.0 173.0 168.0 161.0 169.0 Conversion
rate of 215.degree. C. or higher % 73 89 100 97 100 68 92 100 95
100 fractions Monocyclic aromatic hydrocarbons vol % 40.9 46.5 69.9
50.1 66.7 38.5 48.8 75.9 49.2 73.4 Benzene vol % 0.7 1.6 2.3 2.3
2.7 0.5 2.1 2.6 2.2 2.7 Toluene vol % 1.5 6.4 15.1 10.6 16.4 1.1
8.6 16.7 9.5 16.9 Xylenes vol % 30.2 28.1 28.8 26.8 26.5 31.2 27.4
30.0 28.0 28.4 Ortho vol % 12.5 7.4 6.7 6.4 6.1 14.0 6.5 6.9 7.0
6.5 Meth vol % 14.2 15.5 15.4 14.5 14.2 13.9 15.2 15.9 14.9 15.2
Para vol % 3.5 5.2 6.7 5.9 6.2 3.3 5.7 7.2 6.1 6.7 Ethyl benzene
vol % 0.2 0.9 1.7 1.4 1.3 0.2 1.3 1.9 1.3 1.7 1.5-Cyclic aromatic
hydrocarbons vol % 19.2 10.7 0 2.2 0 18.5 6.1 0 3.2 0 Bicyclic
aromatic hydrocarbons vol % 0.1 0.1 0 0 0 0.4 0.1 0 0.2 0 Tri- or
larger polycyclic aromatic vol % 0 0 0 0 0 0 0 0 0 0 hydrocarbons
Aromatic ring-constituting carbon ratio mol % 41.2 50.7 64.3 53.5
63.6 37.5 51.6 66.8 53.5 66.0 Aromatic ring carbon remaining ratio
-- 0.90 1.11 1.41 1.17 1.39 0.82 1.13 1.46 1.17 1.44
TABLE-US-00008 TABLE 8 Example 35 36 37 38 39 40 41 42 43 44 Feed C
C C C C C C C C C Hydrocracking catalyst H H H H H I I I I I
Reaction temperature .degree. C. 300 320 350 350 350 300 320 350
350 350 Reaction pressure MPa 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0
3.0 LHSV h.sup.-1 1.0 1.0 1.0 1.5 0.5 1.0 1.0 1.0 1.5 0.5
Hydrogen/oil ratio NL/L 1365 1365 1365 1365 1365 1365 1365 1365
1365 1365 Reaction solution yield wt % 70 31 41 32 39 100 100 96 98
80 Sulfur content wt ppm 4 61 14 3 1 3 1 2 3 2 Nitrogen content wt
ppm <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5 <0.5
<0.5 <0.5 Distil- 10 vol % Distillate temperature .degree. C.
<30.0 <30.0 <30.0 <30.0 <30.0 139.0 137.0 59.0 109.0
<30.0 lation 50 vol % Distillate temperature .degree. C. 138.0
<30.0 84.0 <30.0 38.0 208.0 207.0 198.0 206.0 137.0
properties 90 vol % Distillate temperature .degree. C. 220.0 103.0
139.0 105.0 110.0 220.0 220.0 216.0 216.0 212.0 Conversion rate of
215.degree. C. or higher % 65 100 100 100 100 40 41 59 65 81
fractions Monocyclic aromatic hydrocarbons vol % 61.1 31.7 70.6
39.9 60.7 37.1 39.3 42.1 38.8 39.9 Benzene vol % 2.4 5.3 9.3 8.7
13.1 0.3 0.6 1.5 0.9 2.6 Toluene vol % 11.6 17.5 29.2 23.6 35.3 1.8
3.2 7.1 4.3 12.3 Xylenes vol % 35.6 8.8 26.2 7.6 12.4 27.2 27.0
25.2 27.3 17.2 Ortho vol % 7.5 0 5.6 0 0 15.1 11.8 8.2 13.4 4.0
Meth vol % 20.3 8.8 14.2 7.6 12.4 10.5 12.5 13.0 11.3 9.3 Para vol
% 7.8 0 6.4 0 0 1.6 2.7 4.0 2.6 3.9 Ethyl benzene vol % 1.5 0 0 0 0
0 0.3 0.3 0.2 0.5 1.5-Cyclic aromatic hydrocarbons vol % 17.2 0 0 0
0 17.6 14.6 9.9 15.3 4.8 Bicyclic aromatic hydrocarbons vol % 0.2 0
0 0 0 0.3 0.3 0.2 0.7 0 Tri- or larger polycyclic aromatic vol % 0
0 0 0 0 0 0 0 0 0 hydrocarbons Aromatic ring-constituting carbon
ratio mol % 57.3 63.0 77.0 69.0 75.3 35.2 33.5 34.8 35.7 34.3
Aromatic ring carbon remaining ratio -- 1.25 1.38 1.68 1.51 1.65
0.77 0.73 0.76 0.78 0.75
TABLE-US-00009 TABLE 9 Comparative Example 6 7 8 9 10 Feed C C C C
C Hydrocracking catalyst J J J J J Reaction temperature .degree. C.
320 350 380 350 350 Reaction pressure MPa 3.0 3.0 3.0 3.0 3.0 LHSV
h.sup.-1 1.0 1.0 1.0 1.5 0.5 Hydrogen/oil ratio NL/L 1365 1365 1365
1365 1365 Reaction solution yield wt % 83 84 83 90 70 Sulfur
content wt ppm 8 7 6 3 15 Nitrogen content wt ppm <0.5 <0.5
<0.5 <0.5 <0.5 Distillation 10 vol % Distillate
temperature .degree. C. 141.0 141.0 141.0 141.0 143.0 properties 50
vol % Distillate temperature .degree. C. 210.0 211.0 209.0 212.0
209.0 90 vol % Distillate temperature .degree. C. 228.0 232.0 233.0
238.0 224.0 Conversion rate of 215.degree. C. or higher fractions %
27 27 32 3 46 Monocyclic aromatic hydrocarbons vol % 28.9 29.9 30.6
25.6 33.2 Benzene vol % 0 0 0.1 0 0.1 Toluene vol % 0 0.1 0.2 0 0.1
Xylenes vol % 26.1 26.4 26.6 23.9 28.7 Ortho vol % 25.8 26.1 25.7
23.7 28.0 Meth vol % 0.3 0.3 0.8 0.2 0.6 Para vol % 0 0 0.1 0 0.1
Ethyl benzene vol % 0 0 0 0 0 1.5-Cyclic aromatic hydrocarbons vol
% 24.7 23.0 24.0 29.0 20.1 Bicyclic aromatic hydrocarbons vol % 1.6
3.7 5.2 8.4 2.4 Tri- or larger polycyclic aromatic hydrocarbons vol
% 0 0 0 0 0 Aromatic ring-constituting carbon ratio mol % 30.7 32.9
38.3 37.9 34.6 Aromatic ring carbon remaining ratio -- 0.67 0.72
0.84 0.83 0.76
Examples 45 to 47
[0129] The hydrocracking reactions were carried out under the same
conditions as in Example 4, except for the LHSV of 0.5 h.sup.-1,
the hydrogen/oil ratio of 1365 NL/L, the reaction temperature of
320.degree. C., and the reaction pressure of 5.0 MPa in Example 45,
the reaction pressure of 7.0 MPa in Example 46, and the reaction
pressure of 9.0 MPa in Example 47. The properties of the product
oil are shown in Table 10.
TABLE-US-00010 TABLE 10 Example 45 46 47 Feed C C C Hydrocracking
catalyst A A A Reaction temperature .degree. C. 320 320 320
Reaction pressure MPa 5.0 7.0 9.0 LHSV h.sup.-1 0.5 0.5 0.5
Hydrogen/oil ratio NL/L 1365 1365 1365 Reaction solution yield wt %
85 84 85 Sulfur content wt ppm 13 7 4 Nitrogen content wt ppm
<0.5 <0.5 <0.5 Distillation 10 vol % Distillate
temperature .degree. C. 121.0 110.5 110.5 properties 50 vol %
Distillate temperature .degree. C. 207.0 203.0 203.0 90 vol %
Distillate temperature .degree. C. 215.0 214.5 215.0 Conversion
rate of 215.degree. C. or higher fractions % 84 89 86 Monocyclic
aromatic hydrocarbons vol % 32.5 35.4 34.5 Benzene vol % 0.8 1.2
1.1 Toluene vol % 3.2 4.9 4.5 Xylenes vol % 18.5 18.7 18.2 Ortho
vol % 7.2 5.7 5.6 Meth vol % 9.3 10.2 9.9 Para vol % 2.0 2.8 2.7
Ethyl benzene vol % 0.1 0.2 0.2 1.5-Cyclic aromatic hydrocarbons
vol % 6.8 5.4 5.4 Bicyclic aromatic hydrocarbons vol % 0 0.1 0 Tri-
or larger polycyclic aromatic hydrocarbons vol % 0 0 0 Aromatic
ring-constituting carbon ratio mol % 28.6 30.9 30.0 Aromatic ring
carbon remaining ratio -- 0.63 0.68 0.66
[0130] As clearly shown by Examples 6 to 47 in Tables 5 to 8, and
10, it has been confirmed that as compared with the case of using a
conventional hydrocracking catalyst which has been widely used for
hydrocracking reaction (Comparative Examples 6 to 10),
hydrocracking of specific hydrocarbon feedstocks using a suitable
hydrocracking catalyst can effectively proceed the conversion of
bicyclic aromatic hydrocarbons to desired monocyclic aromatic
hydrocarbons (alkylbenzenes), and particularly high value-added BTX
fractions such as benzene and toluene can be obtained at a high
yield. It can also be seen that the hydrocracking is effective for
reducing impurities such as sulfur and nitrogen components.
[0131] The properties of the feeds and product oils in the above
Examples and Comparative Examples were analyzed using the following
methods.
[0132] The density was measured according to the oscillating
density test method of JIS K2249, and the distillation
characteristics were measured according to the atmospheric
distillation test method of JIS K2254.
[0133] The aromatic ring-constituting carbon ratio was measured by
a nuclear magnetic resonance (NMR) analyzer (GSX270 manufactured by
JEOL Ltd.) using deuteriochloroform as a solvent and
tetramethylsilane (0 ppm) as an internal standard.
[0134] The aromatic ring-constituting carbons and aliphatic
structure-forming carbons for each carbon-type group were
quantitatively determined by calculating from the integration ratio
of signals of the Fourier transformed spectrum based on the
measurement under the conditions of an SGNNE mode, 32768 data
points, observed frequency domain width of 27027 Hz, a pulse width
of 2 .mu.s, a pulse waiting time of 30 S and Number of Excitations
of 2000 times. The carbon atoms having 120 to 150 ppm shift values
in the resulting spectrum are deemed to belong to aromatic carbons
and indicated by mol % of the total carbon atoms.
[0135] The composition of monocyclic aromatic hydrocarbons
(alkylbenzenes) (benzene, toluene, and xylenes) and the composition
of 1.5-cyclic aromatic hydrocarbons (tetralins) were measured by a
total hydrocarbon composition analyzer (manufactured by Shimadzu
Corp.) and calculated according to JIS K2536.
[0136] The type analysis (ring analysis) of aromatic compounds was
carried out according to the method of Japan Petroleum Institute
(JPI-5S-49-97) using high performance liquid chromatography (HPLC),
in which n-hexane was used as a mobile phase and the RI method was
used as a detector.
[0137] The sulfur content was measured according to JIS K2541
Determination of sulfur content, in which X-ray fluorescence method
was applied to a high concentration sample and the coulometric
microtitration was applied to a low concentration sample. The
nitrogen content was analyzed by the chemiluminescence method
according to JIS K2609 Determination of nitrogen content.
[0138] The bromine number was determined by the electrometric
titration according to JIS K2605 Determination of bromine
number.
INDUSTRIAL APPLICABILITY
[0139] As mentioned above, according to the present invention
polycyclic aromatic hydrocarbons which have been used only for a
fuel such as heavy oil or gas oil can be effectively and
selectively converted into monocyclic aromatic hydrocarbons, which
are higher valuable alkylbenzenes, by hydrocracking specific
feedstocks under specific operating conditions without problems
such as coking. Therefore, it is possible to use the fractions
which have not been used as a feed for monocyclic aromatic
hydrocarbons, and thus to utilize petroleum resources
effectively.
* * * * *