U.S. patent application number 13/138082 was filed with the patent office on 2011-11-03 for catalyst for producing monocyclic aromatic hydrocarbons, and method for producing monocyclic aromatic hydrocarbons.
Invention is credited to Yuko Aoki, Kazuaki Hayasaka, Masahide Kobayashi, Shinichiro Yanagawa.
Application Number | 20110270004 13/138082 |
Document ID | / |
Family ID | 43410665 |
Filed Date | 2011-11-03 |
United States Patent
Application |
20110270004 |
Kind Code |
A1 |
Yanagawa; Shinichiro ; et
al. |
November 3, 2011 |
CATALYST FOR PRODUCING MONOCYCLIC AROMATIC HYDROCARBONS, AND METHOD
FOR PRODUCING MONOCYCLIC AROMATIC HYDROCARBONS
Abstract
A catalyst for producing monocyclic aromatic hydrocarbons of 6
to 8 carbon number from a feedstock oil having a 10 volume %
distillation temperature of at least 140.degree. C. and an end
point temperature of not more than 400.degree. C., or a feedstock
oil having a 10 volume % distillation temperature of at least
140.degree. C. and a 90 volume % distillation temperature of not
more than 360.degree. C., wherein the catalyst contains a
crystalline aluminosilicate, gallium and/or zinc, and phosphorus,
and the amount of phosphorus supported on the crystalline
aluminosilicate is within a range from 0.1 to 1.9% by mass based on
the mass of the crystalline aluminosilicate; and a method for
producing monocyclic aromatic hydrocarbons, the method involving
bringing a feedstock oil having a 10 volume % distillation
temperature of at least 140.degree. C. and an end point temperature
of not more than 400.degree. C., or a feedstock oil having a 10
volume % distillation temperature of at least 140.degree. C. and a
90 volume % distillation temperature of not more than 360.degree.
C., into contact with the above-mentioned catalyst for producing
monocyclic aromatic hydrocarbons.
Inventors: |
Yanagawa; Shinichiro;
(Tokyo, JP) ; Kobayashi; Masahide; (Tokyo, JP)
; Aoki; Yuko; (Tokyo, JP) ; Hayasaka; Kazuaki;
(Tokyo, JP) |
Family ID: |
43410665 |
Appl. No.: |
13/138082 |
Filed: |
March 26, 2010 |
PCT Filed: |
March 26, 2010 |
PCT NO: |
PCT/JP2010/002171 |
371 Date: |
June 28, 2011 |
Current U.S.
Class: |
585/400 ;
502/214; 502/61 |
Current CPC
Class: |
C07C 4/06 20130101; C10G
2300/301 20130101; C07C 2529/40 20130101; C10G 2300/1051 20130101;
B01J 37/28 20130101; C07C 2529/06 20130101; C10G 2300/1033
20130101; C10G 2300/1059 20130101; C07C 2529/87 20130101; B01J
29/061 20130101; C10G 45/68 20130101; C10G 2400/30 20130101; C10G
2300/1048 20130101; C10G 2300/1055 20130101; B01J 29/405 20130101;
C10G 2300/1044 20130101; B01J 2229/37 20130101 |
Class at
Publication: |
585/400 ;
502/214; 502/61 |
International
Class: |
C07C 15/02 20060101
C07C015/02; B01J 29/40 20060101 B01J029/40; B01J 29/18 20060101
B01J029/18; B01J 27/182 20060101 B01J027/182 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 30, 2009 |
JP |
2009-155984 |
Claims
1. A catalyst for producing monocyclic aromatic hydrocarbons, used
for producing monocyclic aromatic hydrocarbons of 6 to 8 carbon
number from a feedstock oil having a 10 volume % distillation
temperature of at least 140.degree. C. and an end point temperature
of not more than 400.degree. C., or a feedstock oil having a 10
volume % distillation temperature of at least 140.degree. C. and a
90 volume % distillation temperature of not more than 360.degree.
C., wherein the catalyst comprises a crystalline aluminosilicate,
gallium and/or zinc, and phosphorus, and the amount of phosphorus
supported on the crystalline aluminosilicate is within a range from
0.1 to 1.9% by mass based on the mass of the crystalline
aluminosilicate.
2. A catalyst for producing monocyclic aromatic hydrocarbons, used
for producing monocyclic aromatic hydrocarbons of 6 to 8 carbon
number from a feedstock oil having a 10 volume % distillation
temperature of at least 140.degree. C. and an end point temperature
of not more than 400.degree. C., or a feedstock oil having a 10
volume % distillation temperature of at least 140.degree. C. and a
90 volume % distillation temperature of not more than 360.degree.
C., wherein the catalyst comprises a crystalline aluminosilicate,
gallium and/or zinc, and phosphorus, and the amount of phosphorus
is within a range from 0.1 to 5.0% by mass based on the mass of the
catalyst.
3. The catalyst for producing monocyclic aromatic hydrocarbons
according to claim 1 or 2, wherein the crystalline aluminosilicate
is a pentasil-type zeolite.
4. The catalyst for producing monocyclic aromatic hydrocarbons
according to claim 1 or 2, wherein the crystalline aluminosilicate
is an MFI-type zeolite.
5. A method for producing monocyclic aromatic hydrocarbons of 6 to
8 carbon number, the method comprising bringing a feedstock oil
having a 10 volume % distillation temperature of at least
140.degree. C. and an end point temperature of not more than
400.degree. C., or a feedstock oil having a 10 volume %
distillation temperature of at least 140.degree. C. and a 90 volume
% distillation temperature of not more than 360.degree. C., into
contact with the catalyst for producing monocyclic aromatic
hydrocarbons according to claim 1 or 2.
6. The method for producing monocyclic aromatic hydrocarbons of 6
to 8 carbon number according to claim 5, wherein a cracked gas oil
produced in a fluid catalytic cracking is used as the feedstock
oil.
7. The method for producing monocyclic aromatic hydrocarbons of 6
to 8 carbon number according to claim 5, wherein the feedstock oil
is brought into contact with the catalyst for producing monocyclic
aromatic hydrocarbons in a fluidized bed reactor.
Description
TECHNICAL FIELD
[0001] The present invention relates to a catalyst for producing
monocyclic aromatic hydrocarbons and a method for producing
monocyclic aromatic hydrocarbons that enable the production of
monocyclic aromatic hydrocarbons from an oil containing a large
amount of polycyclic aromatic hydrocarbons.
[0002] Priority is claimed on Japanese Patent Application No.
2009-155984, filed Jun. 30, 2009, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] Light cycle oil (hereinafter also referred to as LCO), which
is a cracked gas oil produced in a fluid catalytic cracking,
contains a large amount of polycyclic aromatic hydrocarbons, and
has been used as a gas oil or a heating oil. However, in recent
years, investigations have been conducted into the possibilities of
obtaining, from LCO, monocyclic aromatic hydrocarbons of 6 to 8
carbon number (such as benzene, toluene, xylene and ethylbenzene),
which can be used as high-octane gasoline base stocks or
petrochemical feedstocks, and offer significant added value.
[0004] For example, Patent Documents 1 to 3 propose methods that
use zeolite catalysts to produce monocyclic aromatic hydrocarbons
from the polycyclic aromatic hydrocarbons contained in large
amounts within LCO and the like.
[0005] However, in the methods disclosed in Patent Documents 1 to
3, the yields of monocyclic aromatic hydrocarbons of 6 to 8 carbon
number were not entirely satisfactory.
[0006] When monocyclic aromatic hydrocarbons are produced from a
heavy feedstock oil containing polycyclic aromatic hydrocarbons,
large amounts of carbon matter are deposited on the catalyst,
causing a rapid deterioration in the catalytic activity, and
therefore a catalyst regeneration process that removes this carbon
matter must be performed frequently. Further, in those cases where
a circulating fluidized bed is employed, which is a process in
which the reaction and catalyst regeneration are repeated in an
efficient manner, the temperature for the catalyst regeneration
must be set to a higher temperature than the reaction temperature,
resulting in a particularly severe temperature environment for the
catalyst.
[0007] Under these types of severe conditions, if a zeolite
catalyst is used as the catalyst, then the catalyst tends to suffer
from hydrothermal degradation, causing a deterioration in the
reaction activity over time, and therefore improvements in the
hydrothermal stability of the catalyst are required. However, the
zeolite catalysts disclosed in Patent Documents 1 to 3 employ no
measures to improve the hydrothermal stability, and offer very
little practical usability.
[0008] Examples of known methods for improving the hydrothermal
stability include a method that uses a zeolite having a high Si/Al
ratio, a method in which the catalyst is subjected to a preliminary
hydrothermal treatment to stabilize the catalyst, such as USY
zeolite, a method in which phosphorus is added to a zeolite, a
method in which a rare earth metal is added to a zeolite, and a
method that involves improving the structure-directing agent used
during the synthesis of a zeolite.
[0009] Of these methods, the addition of phosphorus not only
improves the hydrothermal stability, but also provides other known
effects such as an improvement in selectivity due to suppression of
carbon matter deposition during fluid catalytic cracking, and an
improvement in the abrasion resistance of the binder. Accordingly,
this method is frequently applied to catalysts used in catalytic
cracking reactions.
[0010] Examples of catalytic cracking catalysts prepared by adding
phosphorus to a zeolite include those disclosed in Patent Documents
4 to 6.
[0011] Namely, Patent Document 4 discloses a method for producing
olefins from naphtha using a catalyst containing ZSM-5 to which has
been added phosphorus, as well as gallium, germanium and/or tin. In
Patent Document 4, phosphorus is added for the purposes of
suppressing the production of methane and aromatics in order to
enhance the selectivity for olefin production, and ensuring a high
degree of activity even for a short contact time, thereby improving
the yield of olefins.
[0012] Patent Document 5 discloses a method for producing olefins
in a high yield from heavy hydrocarbons by using a catalyst
prepared by supporting phosphorus on ZSM-5 containing zirconium and
a rare earth element, and a catalyst containing a USY zeolite, an
REY zeolite, kaolin, silica and alumina.
[0013] Patent Document 6 discloses a method for producing ethylene
and propylene in a high yield by transforming hydrocarbons using a
catalyst containing ZSM-5 having phosphorus and a transition metal
element supported thereon.
[0014] As mentioned above, the addition of phosphorus to zeolites
has been disclosed in Patent Documents 4 to 6, but in each of these
documents, the main purpose was improvement of the olefin yield,
and monocyclic aromatic hydrocarbons of 6 to 8 carbon number were
not able to be produced at high yield. For example, Table 2 in
Patent Document 6 discloses the yields for olefins (ethylene and
propylene) and BTX (benzene, toluene and xylene), and whereas the
yield for the olefins was 40% by mass, the yield for BTX was a low
value of approximately 6% by mass.
[0015] Accordingly, a catalyst for producing monocyclic aromatic
hydrocarbons that is capable of producing monocyclic aromatic
hydrocarbons of 6 to 8 carbon number in a high yield from a
feedstock oil containing polycyclic aromatic hydrocarbons, and also
capable of preventing any deterioration over time in the yield of
the monocyclic aromatic hydrocarbons is currently not known.
DOCUMENTS OF RELATED ART
Patent Document
[Patent Document 1]
[0016] Japanese Unexamined Patent Application, First Publication
No. Hei 3-2128
[Patent Document 2]
[0016] [0017] Japanese Unexamined Patent Application, First
Publication No. Hei 3-52993
[Patent Document 3]
[0017] [0018] Japanese Unexamined Patent Application, First
Publication No. Hei 3-26791
[Patent Document 4]
[0018] [0019] Published Japanese Translation No. 2002-525380 of
PCT
[Patent Document 5]
[0019] [0020] Japanese Unexamined Patent Application, First
Publication No. 2007-190520
[Patent Document 6]
[0020] [0021] Published Japanese Translation No. 2007-530266 of
PCT
SUMMARY OF INVENTION
Problems to be Solved by the Invention
[0022] An object of the present invention is to provide a catalyst
for producing monocyclic aromatic hydrocarbons and a method for
producing monocyclic aromatic hydrocarbons that enable the
production of monocyclic aromatic hydrocarbons of 6 to 8 carbon
number in a high yield from a feedstock oil containing polycyclic
aromatic hydrocarbons, and also enable the prevention of any
deterioration over time in the yield of the monocyclic aromatic
hydrocarbons of 6 to 8 carbon number.
Means to Solve the Problems
[0023] [1] A catalyst for producing monocyclic aromatic
hydrocarbons, used for producing monocyclic aromatic hydrocarbons
of 6 to 8 carbon number from a feedstock oil having a 10 volume %
distillation temperature of at least 140.degree. C. and an end
point temperature of not more than 400.degree. C., or a feedstock
oil having a 10 volume % distillation temperature of at least
140.degree. C. and a 90 volume % distillation temperature of not
more than 350.degree. C., wherein
[0024] the catalyst contains a crystalline aluminosilicate, gallium
and/or zinc, and phosphorus, and the amount of phosphorus supported
on the crystalline aluminosilicate is within a range from 0.1 to
1.9% by mass based on the mass of the crystalline
aluminosilicate.
[2] A catalyst for producing monocyclic aromatic hydrocarbons, used
for producing monocyclic aromatic hydrocarbons of 6 to 8 carbon
number from a feedstock oil having a 10 volume % distillation
temperature of at least 140.degree. C. and an end point temperature
of not more than 400.degree. C., or a feedstock oil having a 10
volume % distillation temperature of at least 140.degree. C. and a
90 volume % distillation temperature of not more than 360.degree.
C., wherein
[0025] the catalyst contains a crystalline aluminosilicate, gallium
and/or zinc, and phosphorus, and the amount of phosphorus is within
a range from 0.1 to 5.0% by mass based on the mass of the
catalyst.
[3] The catalyst for producing monocyclic aromatic hydrocarbons
according to [1] or [2], wherein the crystalline aluminosilicate is
a pentasil-type zeolite. [4] The catalyst for producing monocyclic
aromatic hydrocarbons according to any one of [1] to [3], wherein
the crystalline aluminosilicate is an MFI-type zeolite. [5] A
method for producing monocyclic aromatic hydrocarbons of 6 to 8
carbon number, the method including bringing a feedstock oil having
a 10 volume % distillation temperature of at least 140.degree. C.
and an end point temperature of not more than 400.degree. C., or a
feedstock oil having a 10 volume % distillation temperature of at
least 140.degree. C. and a 90 volume % distillation temperature of
not more than 350.degree. C., into contact with the catalyst for
producing monocyclic aromatic hydrocarbons according to any one of
[1] to [4]. [6] The method for producing monocyclic aromatic
hydrocarbons of 6 to 8 carbon number according to [5], wherein a
cracked gas oil produced in a fluid catalytic cracking is used as
the feedstock oil. [7] The method for producing monocyclic aromatic
hydrocarbons of 6 to 8 carbon number according to [5] or [6],
wherein the feedstock oil is brought into contact with the catalyst
for producing monocyclic aromatic hydrocarbons in a fluidized bed
reactor.
Effect of the Invention
[0026] The catalyst for producing monocyclic aromatic hydrocarbons
and the method for producing monocyclic aromatic hydrocarbons of 6
to 8 carbon number according to the present invention enable the
production of monocyclic aromatic hydrocarbons of 6 to 8 carbon
number in a high yield from a feedstock oil containing polycyclic
aromatic hydrocarbons, and also enable the prevention of any
deterioration over time in the yield of the monocyclic aromatic
hydrocarbons of 6 to 8 carbon number.
DESCRIPTION OF EMBODIMENTS
[0027] (Catalyst for Producing Monocyclic Aromatic
Hydrocarbons)
[0028] The catalyst for producing monocyclic aromatic hydrocarbons
according to the present invention (hereinafter often referred to
as "the catalyst") is used for producing monocyclic aromatic
hydrocarbons of 6 to 8 carbon number (hereinafter often abbreviated
as "monocyclic aromatic hydrocarbons") from a feedstock oil
containing polycyclic aromatic hydrocarbons and saturated
hydrocarbons, and contains a crystalline aluminosilicate, gallium
and phosphorus.
[0029] [Crystalline Aluminosilicate]
[0030] Although there are no particular limitations on the
crystalline aluminosilicate, medium pore size zeolites such as
zeolites with MFI, MEL, TON, MTT, MRE, FER, AEL and EUO type
crystal structures are preferred, and in terms of maximizing the
yield of monocyclic aromatic hydrocarbons, pentasil-type zeolites
are more preferred, and zeolites with MFI-type and/or MEL-type
crystal structures are particularly desirable.
[0031] MFI-type and MEL-type zeolites are included within the
conventional zeolite structures published by The Structure
Commission of the International Zeolite Association (Atlas of
Zeolite Structure Types, W. M. Meiyer and D. H. Olson (1978),
distributed by Polycrystal Book Service, Pittsburgh, Pa.
(USA)).
[0032] The amount of the crystalline aluminosilicate within the
catalyst, relative to a value of 100% for the entire catalyst, is
preferably within a range from 10 to 95% by mass, more preferably
from 20 to 80% by mass, and still more preferably from 25 to 70% by
mass. Provided the amount of the crystalline aluminosilicate is not
less than 10% by mass and not more than 95% by mass, a
satisfactorily high level of catalytic activity can be
achieved.
[0033] [Gallium]
[0034] Examples of the form of the gallium contained within the
catalyst of the present invention include catalysts in which the
gallium is incorporated within the lattice framework of the
crystalline aluminosilicate (crystalline aluminogallosilicates),
catalysts in which gallium is supported on the crystalline
aluminosilicate (gallium-supporting crystalline aluminosilicates),
and catalysts including both of these forms.
[0035] A crystalline aluminogallosilicate has a structure in which
SiO.sub.4, AlO.sub.4 and GaO.sub.4 structures adopt tetrahedral
coordination within the framework. A crystalline
aluminogallosilicate can be obtained, for example, by gel
crystallization via hydrothermal synthesis, by a method in which
gallium is inserted into the lattice framework of a crystalline
aluminosilicate, or by a method in which aluminum is inserted into
the lattice framework of a crystalline gallosilicate.
[0036] A gallium-supporting crystalline aluminosilicate can
obtained by supporting gallium on a crystalline aluminosilicate
using a conventional method such as an ion-exchange method or
impregnation method. There are no particular limitations on the
gallium source used in these methods, and examples include gallium
salts such as gallium nitrate and gallium chloride, and gallium
oxide.
[0037] The amount of gallium within the catalyst of the present
invention, relative to a value of 100% for the total mass of the
crystalline aluminosilicate, is preferably within a range from 0.01
to 5.0% by mass.
[0038] [Zinc]
[0039] Examples of the form of the zinc contained within the
catalyst of the present invention include catalysts in which the
zinc is incorporated within the lattice framework of the
crystalline aluminosilicate (crystalline aluminozincosilicates),
catalysts in which zinc is supported on the crystalline
aluminosilicate (zinc-supporting crystalline aluminosilicates), and
catalysts including both of these forms.
[0040] A crystalline aluminozincosilicate has a structure in which
SiO.sub.4, AlO.sub.4 and ZnO.sub.4 structures exist within the
framework. A crystalline aluminozincosilicate can be obtained, for
example, by gel crystallization via hydrothermal synthesis, by a
method in which zinc is inserted into the lattice framework of a
crystalline aluminosilicate, or by a method in which aluminum is
inserted into the lattice framework of a crystalline
zincosilicate.
[0041] A zinc-supporting crystalline aluminosilicate can obtained
by supporting zinc on a crystalline aluminosilicate using a
conventional method such as an ion-exchange method or impregnation
method. There are no particular limitations on the zinc source used
in these methods, and examples include zinc salts such as zinc
nitrate and zinc chloride, and zinc oxide.
[0042] The amount of zinc within the catalyst of the present
invention, relative to a value of 100% for the total mass of the
crystalline aluminosilicate, is preferably within a range from 0.01
to 5.0% by mass.
[0043] The catalyst of the present invention may be a catalyst that
contains either one of gallium or zinc, or a catalyst that contains
both gallium and zinc. Further, the catalyst may also contain one
or more other metals in addition to the gallium and/or zinc.
[0044] [Phosphorus]
[0045] The amount of phosphorus supported on the crystalline
aluminosilicate in the catalyst of the present invention, relative
to a value of 100% for the total mass of the crystalline
aluminosilicate, is preferably within a range from 0.1 to 1.9% by
mass. Moreover, the lower limit for this range is more preferably
at least 0.2% by mass, whereas the upper limit is more preferably
not more than 1.5% by mass, and still more preferably not more than
1.2% by mass. By ensuring that the amount of phosphorus supported
on the crystalline aluminosilicate is at least 0.1% by mass,
deterioration over time in the yield of the monocyclic aromatic
hydrocarbons can be prevented, whereas ensuring that the amount is
not more than 1.9% by mass enables the yield of the monocyclic
aromatic hydrocarbons to be increased.
[0046] The upper limit for the amount of phosphorus within the
catalyst of the present invention is considerably lower than the
upper limit for the amount of phosphorus within the catalysts
disclosed in Patent Documents 4 to 6. It is thought that one reason
for this difference is the fact that the feedstock oil for the
reaction in which the catalyst of the present invention is used
contains a large amount of polycyclic aromatic hydrocarbons and
exhibits relatively low reactivity. If the amount of phosphorus is
increased too much, then the feedstock oil is even less likely to
undergo reaction and the aromatic activity decreases, resulting in
a deterioration in the yield of the monocyclic aromatic
hydrocarbons. In contrast, the feedstock oils in Patent Documents 4
to 6 (such as a vacuum gas oil used as the feedstock oil for a
fluid catalytic cracking) are heavy, have large molecular weights
and are adsorbed readily onto the catalyst, and are therefore
cracked more readily than fractions such as LCO. Moreover, because
cracking to form light olefins is relatively easy, even if a large
amount of phosphorus is supported on the catalyst and the aromatic
activity decreases to some extent, this does not cause significant
problems.
[0047] There are no particular limitations on the method used for
incorporating the phosphorus within the catalyst of the present
invention, and examples include methods in which an ion-exchange
method or impregnation method or the like is used to incorporate a
phosphorus compound within a crystalline aluminosilicate,
crystalline aluminogallosilicate or crystalline
aluminozincosilicate, thereby substituting a portion of the
framework of the crystalline aluminosilicate with phosphorus, and
methods in which a crystallization promoter containing phosphorus
is used during synthesis of the zeolite. Although there are no
particular limitations on the phosphate ion-containing aqueous
solution used during the above method, a solution prepared by
dissolving phosphoric acid, diammonium hydrogen phosphate, ammonium
dihydrogen phosphate or another water-soluble phosphate salt in
water at an arbitrary concentration can be used particularly
favorably.
[0048] The catalyst of the present invention can be obtained by
calcining (at a calcination temperature of 300 to 900.degree. C.)
an above-mentioned phosphorus-supporting crystalline
aluminogallosilicate or crystalline aluminozincosilicate, or a
crystalline aluminosilicate having gallium/zinc and phosphorus
supported thereon.
[0049] [Form]
[0050] The catalyst of the present invention is used in the form of
a powder, granules or pellets or the like, depending on the
reaction format. For example, a powder is used in the case of a
fluidized bed, whereas granules or pellets are used in the case of
a fixed bed. The average particle size of the catalyst used in a
fluidized bed is preferably within a range from 30 to 180 .mu.m,
and more preferably from 50 to 100 .mu.m. Further, the bulk density
of the catalyst used in a fluidized bed is preferably within a
range from 0.4 to 1.8 g/cc, and more preferably from 0.5 to 1.0
g/cc.
[0051] The average particle size describes the particle size at
which the particle size distribution obtained by classification
using sieves reaches 50% by mass, whereas the bulk density refers
to the value measured using the method prescribed in JIS R
9301-2-3.
[0052] In order to obtain a catalyst in granular or pellet form, if
necessary, an inert oxide may be added to the crystalline
aluminosilicate or catalyst as a binder or the like, with the
resulting mixture then molded using any of various molding
apparatus.
[0053] In those cases where the catalyst of the present invention
contains an inorganic oxide such as a binder, a compound that
contains phosphorus may also be used as the binder.
[0054] Further, in those cases where the catalyst contains an
inorganic oxide such as a binder, the catalyst may be produced by
mixing the binder and the crystalline aluminosilicate, and
subsequently adding the gallium and/or zinc and the phosphorus, or
by mixing the binder and the gallium- and/or zinc-supporting
crystalline aluminosilicate, or mixing the binder and the
crystalline aluminogallosilicate and/or crystalline
aluminozincosilicate, and subsequently adding the phosphorus.
[0055] In those cases where the catalyst contains an inorganic
oxide such as a binder, the amount of phosphorus relative to the
total mass of the catalyst is preferably within a range from 0.1 to
5.0% by mass, and the lower limit for this range is more preferably
at least 0.2% by mass, whereas the upper limit is more preferably
not more than 3.0% by mass, and still more preferably not more than
2.0% by mass. By ensuring that the amount of phosphorus is at least
0.1% by mass of the total mass of the catalyst, deterioration over
time in the yield of the monocyclic aromatic hydrocarbons can be
prevented, whereas ensuring that the amount of phosphorus is not
more than 5.0% by mass enables the yield of the monocyclic aromatic
hydrocarbons to be increased.
(Method for Producing Monocyclic Aromatic Hydrocarbons)
[0056] The method for producing monocyclic aromatic hydrocarbons
according to the present invention involves bringing a feedstock
oil into contact with the above-mentioned catalyst to effect a
reaction.
[0057] In this reaction, saturated hydrocarbons function as
hydrogen donor sources, and a hydrogen transfer reaction from the
saturated hydrocarbons is used to convert polycyclic aromatic
hydrocarbons into monocyclic aromatic hydrocarbons.
[0058] [Feedstock Oil]
[0059] The feedstock oil used in the present invention is either an
oil having a 10 volume % distillation temperature of at least
140.degree. C. and an end point temperature of not more than
400.degree. C., or an oil having a 10 volume % distillation
temperature of at least 140.degree. C. and a 90 volume %
distillation temperature of not more than 360.degree. C. With an
oil having a 10 volume % distillation temperature of less than
140.degree. C., the reaction involves production of BTX from light
compounds, which is unsuitable in the present embodiment, and
therefore the 10 volume % distillation temperature is preferably at
least 140.degree. C., and more preferably 150.degree. C. or higher.
Further, if an oil having an end point temperature exceeding
400.degree. C. is used, then not only is the yield of monocyclic
aromatic hydrocarbons low, but the amount of coke deposition on the
catalyst also tends to increase, causing a more rapid deterioration
in the catalytic activity, and therefore the end point temperature
of the feedstock oil is preferably not more than 400.degree. C.,
and more preferably 380.degree. C. or lower. Furthermore, if a
feedstock oil having a 90 volume % distillation temperature that
exceeds 360.degree. C. is used, then the amount of coke deposition
on the catalyst tends to increase, causing a more rapid
deterioration in the catalytic activity, and therefore the 90
volume % distillation temperature for the feedstock oil is
preferably not more than 360.degree. C., and more preferably
350.degree. C. or lower.
[0060] In this description, the 10 volume % distillation
temperature, the 90 volume % distillation temperature and the end
point temperature refer to values measured in accordance with the
methods prescribed in JIS K2254 "Petroleum products--determination
of distillation characteristics".
[0061] Examples of feedstock oils having a 10 volume % distillation
temperature of at least 140.degree. C. and an end point temperature
of not more than 400.degree. C., or feedstock oils having a 10
volume % distillation temperature of at least 140.degree. C. and a
90 volume % distillation temperature of not more than 350.degree.
C. include cracked gas oils (LCO) produced in a fluid catalytic
cracking, coal liquefaction oil, hydrocracked oil from heavy oils,
straight-run kerosene, straight-nm gas oil, coker kerosene, coker
gas oil, and hydrocracked oil from oil sands. Of these, cracked gas
oils (LCO) produced in a fluid catalytic cracking are particularly
desirable.
[0062] Further, if the feedstock oil contains a large amount of
polycyclic aromatic hydrocarbons, then the yield of monocyclic
aromatic hydrocarbons of 6 to 8 carbon number tends to decrease,
and therefore the amount of polycyclic aromatic hydrocarbons (the
polycyclic aromatic content) within the feedstock oil is preferably
not more than 50 volume %, and more preferably 30 volume % or
less.
[0063] In this description, the polycyclic aromatic content
describes the combined total of the amount of bicyclic aromatic
hydrocarbons (the bicyclic aromatic content) and the amount of
tricyclic and higher aromatic hydrocarbons (the tricyclic and
higher aromatic content) measured in accordance with JPI-5S-49
"Petroleum Products--Determination of Hydrocarbon Types--High
Performance Liquid Chromatography".
[0064] [Reaction Format]
[0065] Examples of the reaction format used for bringing the
feedstock oil into contact with the catalyst for reaction include
fixed beds, moving beds and fluidized beds. In the present
invention, because a heavy oil fraction is used as the feedstock, a
fluidized bed is preferred as it enables the coke fraction adhered
to the catalyst to be removed in a continuous manner and enables
the reaction to proceed in a stable manner. A continuous
regeneration-type fluidized bed, in which the catalyst is
circulated between the reactor and a regenerator, thereby
continuously repeating a reaction-regeneration cycle, is
particularly desirable. The feedstock oil that makes contact with
the catalyst is preferably in a gaseous state. Further, the
feedstock may be diluted with a gas if required. Furthermore, in
those cases where unreacted feedstock occurs, this may be recycled
as required.
[0066] [Reaction Temperature]
[0067] Although there are no particular limitations on the reaction
temperature during contact of the feedstock oil with the catalyst
for reaction, a reaction temperature of 350 to 700.degree. C. is
preferred. In terms of achieving satisfactory reactivity, the lower
limit is more preferably 450.degree. C. or higher. On the other
hand, an upper limit temperature of not more than 650.degree. C. is
preferable as it is not only more advantageous from an energy
perspective, but also enables reliable regeneration of the
catalyst.
[0068] [Reaction Pressure]
[0069] The reaction pressure during contact of the feedstock oil
with the catalyst for reaction is preferably not more than 1.0
MPaG. Provided the reaction pressure is not more than 1.0 MPaG, the
generation of by-product light gases can be prevented, and the
pressure resistance required for the reaction apparatus can be
lowered.
[0070] [Contact Time]
[0071] There are no particular limitations on the contact time
between the feedstock oil and the catalyst, provided the desired
reaction proceeds satisfactorily, but in terms of the gas transit
time across the catalyst, a time of 1 to 300 seconds is preferred.
The lower limit for this time is more preferably at least 5
seconds, and the upper limit is more preferably 150 seconds or
less. Provided the contact time is at least 1 second, a reliable
reaction can be achieved, whereas provided the contact time is not
more than 300 seconds, deposition of carbon matter on the catalyst
due to coking or the like can be suppressed. Further, the amount of
light gas generated by cracking can also be suppressed.
[0072] In the method for producing monocyclic aromatic hydrocarbons
according to the present invention, hydrogen transfer occurs from
saturated hydrocarbons to the polycyclic aromatic hydrocarbons, and
the polycyclic aromatic hydrocarbons undergo partial hydrogenation
and ring opening, yielding monocyclic aromatic hydrocarbons.
[0073] In the present invention, the yield of monocyclic aromatic
hydrocarbons is preferably at least 15% by mass, more preferably at
least 20% by mass, and still more preferably 25% by mass or
greater. If the yield of monocyclic aromatic hydrocarbons is less
than 15% by mass, then the concentration of the target compounds
within the reaction product is low, and the efficiency with which
those compounds can be recovered tends to deteriorate.
[0074] In the above-mentioned production method of the present
invention, because the catalyst described above is used, monocyclic
aromatic hydrocarbons can be produced in a high yield, and
deterioration over time in the yield of the monocyclic aromatic
hydrocarbons can be prevented.
EXAMPLES
[0075] The present invention is described in more detail below
based on a series of examples and comparative examples, but the
present invention is in no way limited by these examples.
Catalyst Preparation Example 1
[0076] A solution (A) composed of 1706.1 g of sodium silicate (J
Sodium Silicate No. 3, SiO.sub.2: 28 to 30% by mass, Na: 9 to 10%
by mass, remainder: water, manufactured by Nippon Chemical
Industrial Co., Ltd.) and 2227.5 g of water, and a solution (B)
composed of 64.2 g of Al.sub.2(SO.sub.4).sub.3.14.about.18H.sub.2O
(special reagent grade, manufactured by Wako Pure Chemical
Industries, Ltd.), 369.2 g of tetrapropylammonium bromide, 152.1 g
of H.sub.2SO.sub.4 (97% by mass), 326.6 g of NaCl and 2975.7 g of
water were prepared independently.
[0077] Subsequently, with the solution (A) undergoing continuous
stirring at room temperature, the solution (B) was added gradually
to the solution (A). The resulting mixture was stirred vigorously
for 15 minutes using a mixer, thereby breaking up the gel and
forming a uniform fine milky mixture.
[0078] This mixture was placed in a stainless steel autoclave, and
a crystallization operation was performed under conditions
including a temperature of 165.degree. C., a reaction time of 72
hours, a stirring rate of 100 rpm, and under self-generated
pressure. Following completion of the crystallization operation,
the product was filtered, the solid product was recovered, and an
operation of washing the solid product and then performing
filtration was repeated 5 times, using a total of approximately 5
liters of deionized water in the 5 times of operations. The solid
material obtained upon the final filtration was dried at
120.degree. C., and was then calcined under a stream of air at
550.degree. C. for 3 hours.
[0079] Analysis of the resulting calcined product by X-ray
diffraction (apparatus model: Rigaku RINT-2500V) confirmed that the
product had an WI structure. Further, X-ray fluorescence analysis
(apparatus model: Rigaku ZSX101e) revealed a
SiO.sub.2/Al.sub.2O.sub.3 ratio (molar ratio) of 64.8. Based on
these results, the amount of aluminum element incorporated within
the lattice framework was calculated as 1.32% by mass.
[0080] A 30% by mass aqueous solution of ammonium nitrate was added
to the calcined product in a ratio of 5 mL of the aqueous solution
per 1 g of the calcined product, and after heating at 100.degree.
C. with constant stirring for 2 hours, the mixture was filtered and
washed with water. This operation was performed 4 times in total,
and the product was then dried for 3 hours at 120.degree. C.,
yielding an ammonium-type crystalline aluminosilicate.
Subsequently, the product was calcined for 3 hours at 780.degree.
C., yielding a proton-type crystalline aluminosilicate.
[0081] Next, 120 g of the obtained proton-type crystalline
aluminosilicate was impregnated with 120 g of an aqueous solution
of gallium nitrate in order to support 0.2% by mass of gallium
(based on a value of 100% for the total mass of the crystalline
aluminosilicate), and the resulting product was then dried at
120.degree. C. Subsequently, the product was calcined for 3 hours
at 780.degree. C. under a stream of air, yielding a
gallium-supporting crystalline aluminosilicate.
[0082] Subsequently, 30 g of the obtained gallium-supporting
crystalline aluminosilicate was impregnated with 30 g of an aqueous
solution of diammonium hydrogen phosphate in order to support 0.2%
by mass of phosphorus on the aluminosilicate (based on a value of
100% for the total mass of the crystalline aluminosilicate), and
the resulting product was then dried at 120.degree. C.
Subsequently, the product was calcined for 3 hours at 780.degree.
C. under a stream of air, yielding a catalyst containing the
crystalline aluminosilicate, gallium and phosphorus.
[0083] Tablet molding was performed by applying a pressure of 39.2
MPa (400 kgf) to the obtained catalyst, and the resulting tablets
were subjected to coarse crushing and then classified using a 20 to
28 mesh size, thus yielding a granular catalyst 1 (hereinafter
referred to as the "granulated catalyst 1").
Catalyst Preparation Example 2
[0084] With the exception of impregnating the gallium-supporting
crystalline aluminosilicate with 30 g of an aqueous solution of
diammonium hydrogen phosphate that had been prepared with a
concentration sufficient to support 0.7% by mass of phosphorus on
the aluminosilicate (based on a value of 100% for the total mass of
the crystalline aluminosilicate), a granular catalyst 2
(hereinafter referred to as the "granulated catalyst 2") was
obtained in the same manner as that described in catalyst
preparation example 1.
Catalyst Preparation Example 3
[0085] With the exception of impregnating the gallium-supporting
crystalline aluminosilicate with 30 g of an aqueous solution of
diammonium hydrogen phosphate so as to support 1.2% by mass of
phosphorus on the aluminosilicate (based on a value of 100% for the
total mass of the crystalline aluminosilicate), a granular catalyst
3 (hereinafter referred to as the "granulated catalyst 3") was
obtained in the same manner as that described in catalyst
preparation example 1.
Catalyst Preparation Example 4
[0086] 18 g of fumed silica was impregnated with 30 g of an aqueous
solution of diammonium hydrogen phosphate so as to incorporate 8.2%
by mass of phosphorus within the silica, and the resulting product
was dried at 120.degree. C. Subsequently, the product was calcined
for 3 hours at 780.degree. C. under a stream of air, yielding a
phosphorus-containing fumed silica. 18 g of this
phosphorus-containing fumed silica was mixed with 12 g of the
catalyst prepared in catalyst preparation example 2, the thus
obtained catalyst was subjected to tablet molding by applying a
pressure of 39.2 MPa (400 kgf), and the resulting tablets were
subjected to coarse crushing and then classified using a 20 to 28
mesh size, thus yielding a granular catalyst 4 (hereinafter
referred to as the "granulated catalyst 4").
Catalyst Preparation Example 5
[0087] With the exceptions of impregnating 120 g of the proton-type
crystalline aluminosilicate with 30 g of an aqueous solution of
zinc nitrate hexahydrate that had been prepared with a
concentration sufficient to support 0.2% by mass of zinc on the
aluminosilicate (based on a value of 100% for the total mass of the
crystalline aluminosilicate), thus yielding a zinc-supporting
crystalline aluminosilicate, and impregnating the zinc-supporting
crystalline aluminosilicate with 30 g of an aqueous solution of
diammonium hydrogen phosphate that had been prepared with a
concentration sufficient to support 0.7% by mass of phosphorus on
the aluminosilicate (based on a value of 100% for the total mass of
the crystalline aluminosilicate), a granular catalyst 5
(hereinafter referred to as the "granulated catalyst 5") was
obtained in the same manner as that described in catalyst
preparation example 1.
Catalyst Preparation Example 6
[0088] A mixed solution containing 106 g of sodium silicate (J
Sodium Silicate No. 3, SiO.sub.2: 28 to 30% by mass, Na: 9 to 10%
by mass, remainder: water, manufactured by Nippon Chemical
Industrial Co., Ltd.) and pure water was added dropwise to a dilute
sulfuric acid solution to prepare a silica sol aqueous solution
(SiO.sub.2 concentration: 10.2%). Meanwhile, distilled water was
added to 20.4 g of the catalyst prepared in catalyst preparation
example 2 and containing a crystalline aluminosilicate, gallium and
phosphorus to prepare a zeolite slurry. The zeolite slurry was
mixed with 300 g of the silica sol aqueous solution, and the
resulting slurry was spray dried at 250.degree. C., yielding a
spherically shaped catalyst. Subsequently, the catalyst was
calcined for 3 hours at 600.degree. C., yielding a powdered
catalyst 6 (hereinafter referred to as the "powdered catalyst 6")
having an average particle size of 85 .mu.m and a bulk density of
0.75 g/cc.
Catalyst Preparation Example 7
[0089] With the exception of impregnating the gallium-supporting
crystalline aluminosilicate with 30 g of an aqueous solution of
diammonium hydrogen phosphate so as to support 2.0% by mass of
phosphorus on the aluminosilicate (based on a value of 100% for the
total mass of the crystalline aluminosilicate), a granular catalyst
7 (hereinafter referred to as the "granulated catalyst 7") was
obtained in the same manner as that described in catalyst
preparation example 1.
Catalyst Preparation Example 8
[0090] With the exception of not impregnating the
gallium-supporting crystalline aluminosilicate with an aqueous
solution of diammonium hydrogen phosphate, a granular catalyst 8
(hereinafter referred to as the "granulated catalyst 8") was
obtained in the same manner as that described in catalyst
preparation example 1.
[0091] The initial reaction catalytic activity and the catalytic
activity following hydrothermal degradation of the thus obtained
granulated catalysts and powdered catalyst were evaluated using the
methods outlined below.
[Evaluation of Initial Reaction Catalytic Activity: Evaluation
1]
[0092] Using a circulating reaction apparatus in which the reactor
had been charged with a granulated catalyst (10 ml), a feedstock
oil having the properties shown in Table 1 was brought into contact
with the granulated catalyst and reacted under conditions including
a reaction temperature of 550.degree. C. and a reaction pressure of
0 MPaG. During the reaction, nitrogen was introduced as a diluent
so that the contact time between the feedstock oil and the
granulated catalyst was 7 seconds.
[0093] Reaction was continued under these conditions for 30 minutes
to produce monocyclic aromatic hydrocarbons of 6 to 8 carbon
number, and a compositional analysis of the products was performed
using an FID gas chromatograph connected directly to the reaction
apparatus in order to evaluate the initial reaction reactivity. The
evaluation results are shown in Table 2.
[0094] Within the products shown in Table 2, the heavy fraction
refers to hydrocarbons of 6 or more carbon number other than the
monocyclic aromatic hydrocarbons of 6 to 8 carbon number, the light
naphtha refers to hydrocarbons of 5 or 6 carbon number, the
liquefied petroleum gas refers to hydrocarbons of 3 or 4 carbon
number, and the cracked gas refers to hydrocarbons of not more than
2 carbon number.
[Measurement of Yield of Monocyclic Aromatic Hydrocarbons in
Initial Reaction: Evaluation 2]
[0095] Using a circulating reaction apparatus in which the reactor
had been charged with a powdered catalyst (400 g), a feedstock oil
having the properties shown in Table 1 was brought into contact
with the powdered catalyst and reacted under conditions including a
reaction temperature of 550.degree. C. and a reaction pressure of
0.1 MPaG. For the reaction, the powdered catalyst was packed in a
reaction tube with a diameter of 60 mm. During the reaction,
nitrogen was introduced as a diluent so that the contact time
between the feedstock oil and the powdered catalyst was 10
seconds.
[0096] Reaction was continued under these conditions for 10 minutes
to produce monocyclic aromatic hydrocarbons of 6 to 8 carbon
number, and a compositional analysis of the products was performed
using an FID gas chromatograph connected directly to the reaction
apparatus in order to evaluate the initial reaction reactivity. The
evaluation results are shown in Table 2.
[0097] Within the products shown in Table 2, the heavy fraction
refers to hydrocarbons of 6 or more carbon number other than the
monocyclic aromatic hydrocarbons of 6 to 8 carbon number, the light
naphtha refers to hydrocarbons of 5 or 6 carbon number, the
liquefied petroleum gas refers to hydrocarbons of 3 or 4 carbon
number, and the cracked gas refers to hydrocarbons of not more than
2 carbon number.
[Evaluation of Catalytic Activity Following Hydrothermal
Degradation: Evaluation 3]
[0098] The granulated catalysts 1 to 5 and 8 and the powdered
catalyst 6 were each subjected to a hydrothermal treatment under
conditions including a treatment temperature of 650.degree. C. and
a treatment time of 6 hours in a 100% by mass steam atmosphere,
thus preparing pseudo-degraded catalysts 1 to 6 and 8 that had
undergone a simulated hydrothermal degradation.
[0099] With the exception of using these pseudo-degraded catalysts
1 to 5 and 8 instead of the granulated catalysts 1 to 5 and 8, the
same process as that described for evaluation 1 was used to react
the feedstock oil and then perform a compositional analysis of the
resulting products to evaluate the catalytic activity following
hydrothermal degradation. The evaluation results are shown in Table
2.
[0100] Further, with the exception of using the pseudo-degraded
catalyst 6 instead of the powdered catalyst 6, the same process as
that described for evaluation 2 was used to react the feedstock oil
and then perform a compositional analysis of the resulting products
to evaluate the catalytic activity following hydrothermal
degradation. The evaluation results are shown in Table 2.
[Catalyst Degradation]
[0101] A value was calculated for the ratio of the amount (% by
mass) of monocyclic aromatic hydrocarbons of 6 to 8 carbon number
in the catalytic activity evaluation following hydrothermal
degradation (evaluation 3) relative to the amount (% by mass) of
monocyclic aromatic hydrocarbons of 6 to 8 carbon number in the
initial reaction catalytic activity evaluation (evaluation 1 or
evaluation 2) (namely, [amount (% by mass) of monocyclic aromatic
hydrocarbons of 6 to 8 carbon number in evaluation 3]/[amount (% by
mass) of monocyclic aromatic hydrocarbons of 6 to 8 carbon number
in evaluation 1 or evaluation 2]), and this value was used to
determine the degree of catalyst degradation. The results are
summarized in Table 2. A larger value for this property indicates
superior resistance to catalyst degradation.
TABLE-US-00001 TABLE 1 Feedstock properties Analysis method Density
(Measurement temperature: 15.degree. C.) g/cm.sup.3 0.906 JIS K
2249 Kinematic (Measurement temperature: 30.degree. C. ) mm.sup.2/s
3.640 JIS K 2283 viscosity Distillation Initial boiling point
.degree. C. 175.5 JIS K2254 characteristics 10 volume %
distillation temperature .degree. C. 224.5 50 volume % distillation
temperature .degree. C. 274.0 90 volume % distillation temperature
.degree. C. 349.5 End point temperature .degree. C. 376.0
Compositional Saturated content volume % 35 JPI-5S-49 analysis
Olefin content volume % 8 Total aromatic content volume % 57
Monocyclic aromatic content Volume % 23 Bicyclic aromatic content
volume % 25 Tricyclic and higher aromatic content volume % 9
TABLE-US-00002 TABLE 2 Granulated catalyst preparation method
Example 1 Example 2 Example 3 Example 4 Amount of phosphorus within
the catalyst (% by mass) 0.2 0.7 1.2 0.7 Evaluation test Evalu-
Evalu- Evalu- Evalu- Evalu- Evalu- Evalu- Evalu- ation 1 ation 3
ation 1 ation 3 ation 1 ation 3 ation 1 ation 3 Catalyst Granu-
Pseudo- Granu- Pseudo- Granu- Pseudo- Granu- Pseudo- lated degraded
lated degraded lated degraded lated degraded cata- cata- cata-
cata- cata- cata- cata- cata- lyst 1 lyst 1 lyst 2 lyst 2 lyst 3
lyst 3 lyst 4 lyst 4 Products Heavy fraction 48 55 49 52 54 54 53
53 (% by mass) Monocyclic aromatic hydrocarbons of 6 to 8 43 31 38
34 26 27 32 29 carbon atoms Light naphtha 0 0 0 0 1 0 0 0 Liquefied
petroleum gas 1 6 5 5 11 10 6 9 Cracked gas 5 7 7 7 8 8 8 8
Hydrogen 2 1 1 1 1 1 1 1 [Amount (% by mass) of monocyclic aromatic
hydrocarbons 0.72 0.91 1.05 0.91 in evaluation 3]/[amount (% by
mass) of monocyclic aromatic hydrocarbons in evaluation 1 or
evaluation 2] Comparative Comparative Granulated catalyst
preparation method Example 5 example 1 example 2 Amount of
phosphorus within the catalyst (% by mass) 0.7 2.0 0 Evaluation
test Evalu- Evalu- Evalu- Evalu- Evalu- Evalu- ation 2 ation 3
ation 1 ation 3 ation 1 ation 3 Catalyst Granu- Pseudo- Granu- --
Granu- Pseudo- lated degraded lated lated degraded cata- cata-
cata- cata- cata- lyst 5 lyst 5 lyst 6 lyst 7 lyst 7 Products Heavy
fraction 50 52 60 -- 48 64 (% by mass) Monocyclic aromatic
hydrocarbons of 6 to 8 35 32 5 -- 42 14 carbon atoms Light naphtha
0 0 5 -- 0 3 Liquefied petroleum gas 6 7 22 -- 2 12 Cracked gas 8 8
7 -- 6 6 Hydrogen 1 1 0 -- 2 1 [Amount (% by mass) of monocyclic
aromatic hydrocarbons 0.91 -- 0.33 in evaluation 3]/[amount (% by
mass) of monocyclic aromatic hydrocarbons in evaluation 1 or
evaluation 2] Evaluation 1 or evaluation 2: Initial reaction
catalytic activity Evaluation 3: Catalytic activity following
hydrothermal degradation
[Results]
[0102] Examples 1 to 6, which employed the granulated catalysts 1
to 5 and the powdered catalyst 6 respectively, exhibited favorable
initial reaction catalytic activity and favorable catalytic
activity following hydrothermal degradation, and the monocyclic
aromatic hydrocarbons of 6 to 8 carbon number which are objective
products in the present embodiment were able to be obtained in high
yield, both during the initial reaction and following hydrothermal
degradation.
[0103] On the other hand, the results for Comparative Example 1
revealed that if a large amount of phosphorus is added, then the
yield of monocyclic aromatic hydrocarbons of 6 to 8 carbon number
decreases markedly, even during the initial reaction.
[0104] The results for Comparative Example 2 revealed that if a
catalyst with no phosphorus supported thereon is used, despite the
yield of monocyclic aromatic hydrocarbons of 6 to 8 carbon number
is favorable during the initial reaction, the yield decreases
significantly following hydrothermal degradation, and the
deterioration in the catalyst is marked, making the catalyst
impractical.
* * * * *