Note: Descriptions are shown in the official language in which they were submitted.
Description
Method for Aromatization of Propane and Butane
The application claims priority from Chinese Patent Application No.
CN202011478719.8 filed on Dec. 15, 2020.
TECHNICAL FIELD
The present application relates to a method for an aromatization reaction
mainly
based on propane and butane, and specifically relates to a method for
implementing
aromatization after olefin preparation through dehydrogenation of propane and
butane so
as to produce naphtha.
BACKGROUND
It is well known that low-carbon alkanes are abundant in resources and low in
price.
The by-product liquefied petroleum gas of refinery enterprises in China is
rich in a large
amount of propane and butane. At present, there is a big gap between the
separation
technologies for propane and butane and deep processing and utilization of its
downstream
products in China and those of the United States, Europe, Japan and other
countries. Most
of propane and butane are burned as a civil fuel, resulting in waste of
resources. It can be
seen that it is a challenge in the refining and chemical industry today how to
effectively
utilize a large number of propane and butane resources produced by oil fields
and
produced as by-products of petrochemical plants.
Meanwhile, the demand for light aromatic hydrocarbons being as important
petrochemical raw materialsõ such as benzene, toluene and xylene (BTX)
increases year
by year with quick development of the three major synthetic materials
(synthetic rubber,
synthetic fiber, synthetic resin) and other fine chemicals. In addition, the
demand for
high-octane gasoline in fuel markets is growing rapidly, and light aromatic
hydrocarbon is
important blending components of high-octane gasoline, so it is particularly
necessary to
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develop production technologies for aromatic hydrocarbons.
Naphtha is used as a main raw material for traditional production of light
aromatic
hydrocarbons, which are prepared by using a catalytic reformer. A catalytic
reforming
technology is a main way for a refinery enterprise to obtain blending
components for
high-octane gasoline and high-quality aromatic hydrocarbons. According to this
technology, straight-run naphtha components are converted into aromatic
hydrocarbons
through reactions such as dehydrogenation, isomerization dehydrogenation and
cyclization
dehydrogenation under the action of catalysts PtRe/C1-A1203 or PtSn/C1-A1203.
Catalytic
reforming has relatively high requirements on the potential content of
aromatic
hydrocarbons and the content of impurities in the raw materials. In addition,
with gradual
increment of a market demand for light aromatic hydrocarbons and limited
supply of
conventional naphtha resources, the market demand on light aromatic
hydrocarbons
cannot be satisfied.
An aromatization technology is a petroleum processing technology developed in
recent years, in which low-carbon hydrocarbons are converted into light
aromatic
hydrocarbons such as BTX, etc. under the action of a modified zeolite catalyst
(ZSM-5
zeolites modified by Zn or Ga, etc.). In terms of raw materials, compared with
olefins with
the same carbon number alkanes, it is difficult for alkanes to generate
carbonium ions and
alkanes are low in aromatization activity. Therefore, when raw materials with
high alkane
content are used, endothermic cracking or dehydrogenation reaction is required
to generate
carbonium ions during activation, and thus the activated raw materials undergo
an
oligomerization cyclization reaction to generate aromatic hydrocarbons. In
recent years,
scholars have carried out a lot of research work on the aromatization of
propane and
butane, optimizing the reaction process conditions, improving the catalysts by
various
methods such as hydrothermal treatment, so as to improve the aromatization
activity and
stability of the catalysts and enhance the carbon deposition resistance of the
catalysts.
Nevertheless, the aromatization of propane and butane generates a large amount
of
methane and ethane by-products due to cracking. Ethane is more difficult to
aromatize due
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Date Recue/Date Received 2021-06-23
to its lower reaction activity, so this part of dry gas cannot be used with a
high value, the
economic evaluation of the device is poor. This limitation causes difficulty
in promotion
of this technology.
Based on the above-mentioned development situation, the present application
proposes a method and an improved device for an aromatization reaction of
olefins
produced by a dehydrogenation reaction of propane and butane to partially or
completely
improve the above-mentioned problems.
SUMMARY
A purpose of the present application is to increase the conversion rate of
catalytic
dehydrogenation of alkane.
Another purpose of the present application is to efficiently implement an
aromatization reaction from propane and butane produced in oil fields or in
petrochemical
plants.
Another purpose of the present application is to increase the conversion rate
of
dehydrogenation of propane and butane, thereby increasing the conversion rate
of
aromatization.
On one hand, the first purpose of the present application is achieved by a
method for
catalytic dehydrogenation of alkane; The method comprises: carrying out a
dehydrogenation reaction of alkane under the action of a dehydrogenation
catalyst to
obtain a dehydrogenation reaction product, wherein an active component in the
dehydrogenation catalyst includes at least one element selected from a group
consisting of
In, Ge, Al, Bi, and Ru.
In other words, in the dehydrogenation catalyst, the active component does not
contain the elements Pt, Cr or V except for the above-mentioned elements, or
the content
of the Pt, Cr or V element is lower than a detection limit of atomic
absorption
spectroscopy specified by IUPAC.
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Date Recue/Date Received 2021-06-23
A method for preparing the dehydrogenation catalyst comprises: carrying out a
reaction of a substance containing at least one element selected from a group
consisting of
In, Ge, Al, Bi and Ru with water; and then carrying out heating treatment to
obtain the
catalyst.
The substance containing element of In, Ge, Al, Bi, or Ru is a kind of
elementary
substance, alloy, carbon oxide or nitrogen oxide.
A temperature of the reaction of the substance containing at least one element
selected from a group consisting of In, Ge, Al, Bi and Ru with water is in a
range of 20
DEG C to 900 DEG C; preferably, the temperature of the reaction is in a range
of 20 DEG
C to 300 DEG C; and more preferably, the temperature of the reaction is in a
range of 100
DEG C to 200 DEG C. A reaction time is in a range of 0.5 h to300 h, preferably
the
reaction time is in a range of lh to 100 h.
In one embodiment, according to the method, the substance containing the
element of
In, Ge, Al, Bi or Ru is firstly soaked in acid liquor/alkaline liquor before
reacting with
water.
The acid liquor is selected from inorganic acids or organic acids, preferably
the
inorganic acids. The alkaline liquor is selected from inorganic bases or
organic bases,
preferably the inorganic bases.
A molar concentration of the inorganic acids or inorganic bases is in a range
of 0.01%
to 20.0%, preferably 0.02% to 5.0%.
Alternatively, a method for preparing the dehydrogenation catalyst comprises:
loading the substance containing at least one element selected from a group
consisting of
In, Ge, Al, Bi and Ru on a carrier; and then carrying out a process for
heating treatment to
obtain the catalyst.
The reaction of loading the substance containing the element selected from a
group
consisting of In, Ge, Al, Bi and Ru on the carrier comprises an immersion
method, a
sol-gel method, a precipitation method, a hydrothermal method, a combustion
method, a
complexing method, a solvothermal method, a sonochemical method, a spraying
method,
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a roller coating method or an ion exchange method. The reaction is not limited
to utilize
the above-mentioned methods, and other methods for preparing catalyst may also
be
selected.
A content of the substance contained in the catalyst is in a range of lOwt% to
60
wt%.
Generally the content of active component in the catalyst refers to the weight
of
metallic oxide in the highest valence state.
In the preparation method of the dehydrogenation catalyst, the substance
containing
the element selected from a group consisting of In, Ge, Al, Bi, or Ru is a
kind of an
elementary substance, alloy, carbon oxide, nitrogen oxide, nitrate, sulfate or
chloride.
The carrier is selected from one or more materials selected from a group
consisting of
a zeolite, SiO2, MgO, ZnA1204, Zn(Gai_x)A1x04, Mg(Ga1_4A1x04, MgA1204, TiO2,
Ga203,
Ce02 and a hollow ceramic sphere. The zeolite is selected from A zeolites, X
zeolites, Y
zeolites, M zeolites, ZSM zeolites, aluminum phosphate zeolites, HMS zeolites,
SBA
zeolites, M4 1 s zeolites and isomorphous substitution of Al and Si zeolites
by heteroatoms
containing P and Ti.
In the above-mentioned two methods for preparing the dehydrogenation catalyst,
the
process of heating treatment includes drying and/or roasting. A drying
temperature is in a
range of 50-300 DEG C, preferably in a range of 80-180 DEG C. A roasting
temperature is
in a range of 300-1100 DEG C, preferably in a range of 500-700 DEG C.
In some embodiments, the method further includes the step of adding an
additive to
the reactants before reaction, or soaking a prepared catalyst in the additive.
The additive is
a compound including one or more elements selected from a group consisting of
alkaline
metals, alkaline earth metals, Ni, Cu, La, Y, Ce, Fe, and Zr.
An amount of the additive is in range of 0% to 30% of the substance (dry
basis), and
preferably the amount is in range of 0.005 wt% to10 wt%.
The additive is a compound including one or more elements selected from a
group
consisting of Ni, Cu, La, Y, Ce, Fe, and Zr.
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The dehydrogenation catalyst prepared by the above-mentioned two methods has a
shell layer with a specific surface area in a range of 100-400 m2/g and a pore
volume in a
range of 0.05-0.1 cm3/g.
For the catalyst with a shell layer structure, the transfer and
supplementation between
a surface material and lattice oxygen in a bulk-phase material is blocked, the
pretreatment
time and induction period of the catalyst are effectively shortened, and the
heat transfer
efficiency of the catalyst is improved as well. In addition, the shell layer
structure of the
catalyst has a dehydrogenation active surface with a relatively large specific
surface area
and a relatively short diffusion path. So the pretreatment time and induction
period of the
catalyst can be further shortened and simultaneously the mass transfer
efficiency is
improved.
The pore diameter of the shell layer of the dehydrogenation catalyst is in a
range of
3nm to 10 nm.
The shell layer of the catalyst has the characteristics of being stable in
structure and
not prone to falling off, so that the catalyst can still maintain an excellent
dehydrogenation
effect after repeated regeneration.
In some embodiments, aluminum oxide is as a dehydrogenation active center of
the
dehydrogenation catalyst.
In the present application, a reaction temperature of catalytic
dehydrogenation of
alkane is in a range of 500 to 660 DEG C.
A pressure at the top of the reactor is in a range of 0.1MPa to 0.5 MPa
(absolute
pressure), and a mass space velocity is in a range of 0.110 to 5 11-1.
A conversion rate of alkane and the selectivity of olefin in a single-pass can
be
improved via using the dehydrogenation catalyst.
In the present application, the number of carbon atoms of alkane is generally
no more
than 6; preferably the number of carbon atoms of alkane is in a range of 2 to
4.
Furthermore, the following reaction-regeneration device for dehydrogenation of
alkane is utilized to increase the conversion rate of alkane with low energy
consumption.
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Date Recue/Date Received 2021-06-23
The reaction-regeneration device for dehydrogenation of alkane of the present
application can also be combined with any dehydrogenation catalyst in the
prior art.
A reaction-regeneration device for dehydrogenation of alkane of the present
application includes:
a reactor,
a regenerator arranged above the reactor,
a spent catalyst riser pipe, being a straight pipe extending in an axial
direction of the
reactor; a first end of the spent catalyst riser pipe being located in a lower
part of the
reactor; a second end of the spent catalyst riser pipe being in the
regenerator from a top of
the reactor;
a regenerated catalyst delivery pipe, being a straight pipe extending in the
axial
direction of the reactor; a first end being located in the regenerator; a
second end of the
regenerated catalyst delivery pipe being in the reactor from a bottom of the
regenerator;
and
a lifting medium pipe, a first end of the lifting medium pipe being arranged
outside
the reactor; and a second end of the lifting medium pipe being located inside
the spent
catalyst riser pipe.
The regenerator includes a regeneration section and a settling section; and
the reactor
comprises a reaction section and a settling section.
A lifting medium is introduced into the lifting medium pipe to drive a spent
catalyst
at the bottom of the reactor to move upwards, and the spent catalyst enters
the regenerator
through the spent catalyst riser pipe.
In a preferable embodiment, the second end of the lifting medium pipe is
located
above an opening of the first end of the spent catalyst riser pipe. When the
lifting medium
is introduced, a negative pressure zone is generated near the first end of the
spent catalyst
riser pipe, and the spent catalyst at the bottom of the reactor can be sucked
into the spent
catalyst riser pipe.
In one embodiment, a gas stripping medium is introduced into the lower part of
the
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Date Recue/Date Received 2021-06-23
reactor to strip off oil gas carried by the spent catalyst falling into the
bottom of the reactor,
and thus oil gas loss is reduced.
In a preferable embodiment, a gas stripping medium distributor is arranged at
the
lower part of the reactor and is located above the first end of the spent
catalyst riser pipe.
The gas stripping medium is introduced into the gas stripping medium
distributor to strip
off the oil gas carried by the spent catalyst falling into the bottom of the
reactor.
The gas stripping medium distributor is one pipe in an annular shape or more
pipes in
annular shapes arranged on a same plane; and nozzles are arranged on the
pipe(s).
In addition, under the driving of the lifting medium, the spent catalyst is
well
suctioned and pushed around the bottom of the spent catalyst riser pipe while
continuously moving upwards along the spent catalyst riser pipe, and the
cyclic driving
force for the catalyst is great. Therefore, the circulation amount of the
catalyst is increased,
and the catalyst-gas ratio is increased, which is beneficial to conversion of
alkane
molecules.
In some embodiments, the first end of the spent catalyst riser pipe is close
to the
bottom of the reactor. After falling into the bottom of the reactor, the
deactivated catalyst
can be quickly delivered to the regenerator to be regenerated, thus occurrence
of a side
reaction is reduced, and the selectivity of olefin is improved.
In one embodiment, the second end of the spent catalyst riser pipe is
configured to be
stuck into a dilute-phase section of the regenerator. Namely, the second end
of the spent
catalyst riser is located at the lower part of the settling section of the
regenerator.
In one embodiment, the second end of the regenerated catalyst delivery pipe is
located in the reactor and located below the settling section of the reactor.
A raw material distributor is arranged at the lower part in the reaction
section of the
reactor, and the second end of the regenerated catalyst delivery pipe is
located above the
raw material distributor. Thus, the regenerated catalyst in the reactor is in
countercurrent
contact with raw materials, the distribution of the residence time of the
catalyst particles in
the reactor is narrow, and the degree of back mixing is low. During the
contact between
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the raw materials and the catalyst, the content of an active catalyst in a
unit contact area is
higher, which can increase the conversion rate of the raw materials.
In some embodiments, the raw material distributor is one pipe in an annular
shape or
more pipes in annular shapes which are arranged on the same plane, and nozzles
are
arranged on the pipe(s). The directions of the nozzles can be upward or
downward.
In the reaction-regeneration device for dehydrogenation of alkane of the
present
application, most sections of the spent catalyst riser pipe and the
regenerated catalyst
delivery pipe are both arranged inside the reactor and the regenerator. In a
catalyst
delivery process, heat loss is reduced and energy consumption is greatly
reduced. The
reactor and the regenerator are arranged in up and down direction, so the
structure is
compact and the occupied space is small.
A gas stripping medium distributor and a fuel distributor are arranged in the
regeneration section of the regenerator. The gas stripping medium distributor
is located
below the fuel distributor.
Both the gas stripping medium distributor and the fuel distributor are one
pipe in an
annular shape or more pipes in annular shapes which are arranged on the same
plane, and
nozzles are arranged on the pipe(s).
Cyclone separators, more preferably two-stage cyclone separators, are
respectively
arranged in the settling section of the regenerator and the settling section
of the reactor.
Other components of the regenerator and the reactor can adopt the arrangement
modes in the prior art, which are not repeated here.
On the other hand, another purpose of the present application is achieved by a
method for dehydrogenation and aromatization of propane and butane, and the
method
comprising:
carrying out a catalytic dehydrogenation reaction of propane and butane to
obtain a
dehydrogenation reaction product; and
carrying out an aromatization reaction of the dehydrogenation reaction product
under
the action of a catalyst to obtain an aromatization product,
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wherein, the above-mentioned catalyst is used as the catalyst for catalytic
dehydrogenation, and the reaction temperature is controlled to be in a range
of 500 DEG C
to 660 DEG C. Other dehydrogenation catalysts of the prior art can be adopted
as well.
Preferably, the above-mentioned dehydrogenation catalyst with the active
component
including at least one element selected from a group consisting of In, Ge, Al,
Bi and Ru is
used.
The catalytic dehydrogenation reaction of alkane in the present application is
preferably carried out in the above-mentioned reaction-regeneration device for
dehydrogenation of alkane.
In one embodiment, ZSM-5 zeolites are used as the catalyst in the
aromatization
reaction. Wherein, an atomic ratio of silicon to aluminum is larger than 10, a
crystal size is
in a range of lOnm to 300 nm, a specific surface area is larger than 150 m2/g,
and a pore
volume is in range of 0.25 cm3/g to 0.29 cm3/g.
Preferably, the atomic ratio of silicon to aluminum is larger than 30.
By reducing the acid center density (high silicon-to-aluminum ratio) and the
crystal
size (nano-scale), the accessibility of the active center is improved, and the
micro-environment in the pores of the zeolites is improved, so as to increase
the selectivity
of gasoline components and delay coking deactivation.
Further, the ZSM-5 zeolites can be loaded with metal elements.
In some embodiments, the aromatization temperature is in a range of 360 DEG C
to
440 DEG C.
The pressure is in a range of 0.5 MPa to 1.0 MPa (absolute pressure), and the
mass
space velocity is in a range of 0.8 11-1 to 1.5 10.
In the present application, the dehydrogenation reaction of alkane is carried
out in a
fluidized bed, and the aromatization reaction of the dehydrogenation product
is carried out
in a fixed bed.
Propane and butane can be mixed according to any ratio.
According to the present application, propane and butane are used as raw
materials,
Date Recue/Date Received 2021-06-23
the dehydrogenation reaction and the aromatization reaction of alkane are
combined to
increase the conversion rate of aromatization and the yield of aromatic
hydrocarbon,
because more olefins are produced by the dehydrogenation reaction of alkane.
The
aromatized product is absorbed by naphtha to produce the gasoline with low-
olefin and
high-octane. Alternatively the olefin of the aromatized product is
hydrogenated and
saturated to produce conventional naphtha which is convenient to transport or
used for
being blended with crude oil. The contradiction between supply and demand of
aromatic
hydrocarbon production is significantly alleviated, high-efficiency conversion
of
low-carbon alkane resources is realized, the production cost is effectively
reduced, and the
comprehensive utilization level of oil gas resources is increased.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 illustrates an embodiment of the reaction-regeneration device for
catalytic
dehydrogenation of propane and butane according to the present application.
Fig. 2 illustrates a flow chat of the aromatization after catalytic
dehydrogenation of
propane and butane according to the present application.
Fig. 3 is schematic view of the pipe in annular shape (including the feeding
annular
pipe in the reactor, the gas stripping medium annular pipe, as well as the
annular pipe
which is used for introducing the fuel or the gas stripping medium into the
regenerator).
DETAILED DESCRIPTION
A method for aromatization from propane and butane as raw materials of the
present
application is further described below in detail. The protection scope of the
present
application is not limited and is defined by the claims. The disclosed
specific details
provide a comprehensive understanding of each disclosed embodiment. However,
those
skilled in the relevant art know that the embodiments can also be implemented
by using
other materials and the like without using one or more of these specific
details.
Unless there is required by the context, in the description and claims, the
terms
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Date Recue/Date Received 2021-06-23
"comprising" and "including" should be understood as open meaning of
comprising, that
is," including, but not limited to".
The "embodiment", "one embodiment", "another embodiment" or "some
embodiments" mentioned in the description refer to that the described specific
features,
structures or characteristics related to the embodiments are included in at
least one
embodiment. Therefore, "the embodiment," "one embodiment," "another
embodiment," or
"some embodiments" do not need to refer to the same embodiment. Moreover,
specific
features, structures or characteristics can be combined in any manner in one
or more
embodiments. Each feature disclosed in the description can be replaced by any
alternative
feature that can provide the same, equal or similar purpose. Therefore, unless
otherwise
specified, the disclosed features are only general examples of equal or
similar features.
The experimental methods that do not indicate specific conditions in the
following
embodiments usually refer to the conventional conditions or the conditions
recommended
by the manufacturer. Unless otherwise specified, all percentages, ratios,
proportions, or
parts are calculated based on the weight.
The term "aromatization" refers to the conversion of low-molecular-weight
hydrocarbons into mixed aromatic hydrocarbons containing benzene, toluene and
xylene
through an aromatization reaction under the action of a catalyst, and
meanwhile a gas
phase containing hydrogen, methane and C2-05 fractions is generated. After
being
separated, mixed aromatic hydrocarbons, light aromatic hydrocarbons and heavy
aromatic
hydrocarbons that meet the standards are finally produced.
'Naphtha" is also called as crude gasoline, which generally contains alkane,
monocyclic alkane, bicyclic alkane, alkylbenzene, benzene, indane and
tetralin. The main
components are C5¨C7 of alkane.
Embodiment 1
According to this embodiment, the dehydrogenation catalyst is prepared by the
following method.
20.0 g of aluminum powder (Al) was added to a 0.15 mo1.1:1 NaOH solution to be
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Date Recue/Date Received 2021-06-23
soaked for 5 minutes. After being filtered, washed with deionized water, the
above treated
aluminum was transferred to a reaction kettle with a PTFE lining and a volume
of 250 mL,
and mixed with 150 mL of deionized water. The reaction kettle containing the
mixture was
sealed, allowed to stand in an oven at 120 DEG C for 12 h. The materials in
the reaction
kettle was taken out and dried in the oven at 120 DEG C to obtain the
dehydrogenation
catalyst for later use.
The prepared catalyst was subjected to being pre-reduced in an H2 (30 mL=min-
1)
atmosphere for 1 h, and then was in contact with propane for reaction at the
reaction
temperature 600 DEG C and the mass space time 4.46 h. The initial conversion
rate,
propylene selectivity and coke yield of the catalyst were tested respectively,
wherein the
initial conversion rate is 38.2%, the propylene selectivity is 64.3%, and the
coke yield is
5.6%.
Embodiment 2
According to this embodiment, the dehydrogenation catalyst is prepared by the
following method:
2.5 g of aluminum chloride (A1C13) and 1.0 g of ruthenium chloride
(RuC13.3H20)
were dissolved in 100 g of water to form a solution A; 10 g of an all-Si
zeolite was added
to 100 g of water and stirred at 60 DEG C to form suspension liquid B. The
solution A was
dropped into the suspension liquid B to get a mixture; the pH of the mixture
was adjusted
.. to about 9 with ammonia water; and then a certain amount of polyethylene
glycol was
added as a dispersant to get a second mixture. The second mixture was
subjected to
reaction in a water bath for 2 h, and subjected to filtration and washing
until no chlorine
ions was detected by using silver nitrate, and then a solid product without
chlorine ions
was obtained. The solid product was carried out drying at 120 DEG C and
roasting at 600
DEG C for 4 hours to obtain the dehydrogenation catalyst.
The prepared catalyst was subjected to being pre-reduced in a CO (30 mL.min-1)
atmosphere for 0.5 h, and then was in contact with propane for reaction at the
reaction
temperature 600 DEG C and the mass space time 4.46 h. The initial conversion
rate,
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propylene selectivity and coke yield of the catalyst were tested respectively,
wherein the
initial conversion rate was 46.5%, the propylene selectivity was 75.2%, and
the coke yield
was 5.0%.
Embodiment 3
According to this embodiment, the dehydrogenation catalyst is prepared by the
following method:
2.5 g of aluminum powder (Al), 2.5 g of ruthenium powder (Ru), 2.5 g of
germanium
powder (Ge) and 2.5 g of indium powder (In) were added to 0.15 mol=L-1 HNO3
solution
to be soaked for 10 min, filtered, washed with deionized water, and
transferred to a reactor
with 250 mL and a PTFE lining. 150 mL of deionized water, 0.5 g of sodium
bicarbonate
(NaHCO3) as an additive, 5 g of tetrapropyl ammonium bromide and 10 g of SiO2
pellets
were added in the reactor to obtain a mixture. The mixture was sealed in the
reactor,
allowed to stand in an oven at 150 DEG C for 6 h, and taken out. After drying,
the SiO2
pellets (named as CAT-1) and matrix products (homogeneous growth, named as CAT-
2)
were sieved out, and both were roasted at 600 DEG C for 4 h.
The prepared catalyst CAT-1 was subjected to being pre-reduced in a CO (30
mL=min-1) atmosphere for 0.5 h and then was in contact with propane for
reaction at the
reaction temperature 600 DEG C and the mass space time 4.46 h. The initial
conversion
rate, propylene selectivity and coke yield of the catalyst were tested
respectively, wherein
the initial conversion rate is 38.0%, the propylene selectivity was 86.3%. The
catalytic
property of the catalyst slowly declined after about 16 h of reaction of the
catalyst, and the
coke yield was about 2.1%.
The prepared catalyst CAT-2 was subjected to being pre-reduced in a CO (30
mL=min-1) atmosphere for 0.5 h and then was in contact with propane for
reaction at the
reaction temperature 600 DEG C and the mass space time 4.46 h. The initial
conversion
rate, propylene selectivity and coke yield of the catalyst were tested
respectively, wherein
the initial conversion rate was 43.3%, the propylene selectivity was 82.3%.
The catalytic
property of the catalyst slowly declined after about 9 h of reaction of the
catalyst, and the
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Date Recue/Date Received 2021-06-23
coke yield was about 3.7%.
Specific Surface Pore Volume Pore Diameter
Area (m2/g) (cm3/g) (nm)
Embodiment 3
(CAT-1) 320.20 0.89 8.41
Embodiment 3
(CAT-2) 160.21 0.15 3.91
Embodiment 4
The dehydrogenation-regeneration reaction device for alkane as shown in Fig. 1
includes a reactor and a regenerator, wherein the regenerator is arranged
above the reactor.
The reactor includes a reactor reaction section 7 and a reactor settling
section 9; and the
regenerator includes a regenerator regeneration section 17 and a regenerator
settling
section 18.
The cross sections of the reactor and the regenerator are both circular.
io A spent
catalyst riser pipe 8 is a straight pipe extending in the axial direction of
the
reactor. The first end of the spent catalyst riser pipe 8 is located in the
reactor reaction
section 7; and the second end of the spent catalyst riser pipe 8 is located in
the regenerator
through the top of the reactor. A regenerated catalyst delivery pipe 11 is a
straight pipe
extending in the axial direction of the reactor. The first end of the
regenerated catalyst
delivery pipe 11 is located in the regenerator; and the second end of the
regenerated
catalyst delivery pipe 11 is located in the reactor through the bottom of the
regenerator.
In this embodiment, the first end of the spent catalyst riser pipe 8 is close
to the
bottom of the reactor; and the second end of the spent catalyst riser pipe 8
is located in the
dilute-phase section of the regenerator regeneration section.
The first end of the regenerated catalyst delivery pipe 11 is close to the
bottom of the
regenerator. A regenerated catalyst can be conveniently conveyed into the
second end
located in the reactor through the first end of the regenerated catalyst
delivery pipe 11, and
then enters the reactor.
Control valves are arranged at appropriate positions in the spent catalyst
riser pipe 8
and the regenerated catalyst delivery pipe 11 to facilitate to control the
flow rate of the
Date Recue/Date Received 2021-06-23
catalyst. In this embodiment, the control valves (111, 81) of both the spent
catalyst riser
pipe 8 and the regenerated catalyst delivery pipe 11 are located at positions
outside the
regenerator and the reactor.
Reactor:
A lifting medium pipe 2 is further arranged in the reactor; the first end of
the lifting
medium pipe 2 is arranged outside the reactor; and the second end of the
lifting medium
pipe 2 is located in the spent catalyst riser pipe 8. A lifting medium is
introduced into the
lifting medium pipe 2; negative pressure is generated near the first end of a
spent catalyst
riser pipe; a spent catalyst at the bottom of the reactor is sucked into the
lifting medium
pipe 2; and the spent catalyst is driven to be lifted and enter the
regenerator. The lifting
medium is selected from water vapor or nitrogen.
A feed distributor 6 for conveying a raw material 5 is arranged in the reactor
reaction
section 7, and a gas stripping medium distributor 4 for conveying a gas
stripping medium
3 is arranged under the feeding distributor 6. Both the feed distributor 6 and
the gas
stripping medium distributor 4 are pipes in annular shapes; and nozzles are
arranged on
the pipes in annular shapes. The raw material 5 or a gas medium is sprayed
into the reactor
through the nozzles of the pipes in annular shapes. The nozzles are arranged
toward
various directions.
The reactor settling section 9 is located above the reactor reaction section
7. The
reactor reaction section is divided into a dense-phase section and a dilute-
phase section;
and the dilute-phase section is located above the dense-phase section. The
second end of
the regenerated catalyst delivery pipe 11 is preferably located in the dilute-
phase section of
the reactor reaction section.
A cyclone separator 10 is arranged in the reactor settling section 9 to
separate the
catalyst from oil gas. The top of the reactor is provided with an oil gas
outlet 12, and the
oil gas is discharged out of the reactor through the oil gas outlet 12 after
being separated
from catalyst.
Re2enerator:
16
Date Recue/Date Received 2021-06-23
The regenerator regeneration section is divided into a dilute-phase section
and a
dense-phase section, and the dilute-phase section is located above the dense-
phase section.
The second end of the spent catalyst riser pipe 8 is located in the dilute-
phase section of
the regenerator regeneration section. Through this arrangement, the spent
catalyst is more
likely to fall into the dense-phase section of the regenerator regeneration
section for a
regeneration reaction.
A gas stripping medium distributor 14 and an air and fuel distributor 16 are
arranged
in the lower part of the regenerator, and the air and fuel distributor 16 is
located above the
gas stripping medium distributor 14. Both the gas stripping medium distributor
14 and the
air and fuel distributor 16 are pipes in annular shapes, and nozzles are
arranged on the
pipes in annular shapes. Air and fuel 15 or a gas stripping medium 13 is
sprayed into the
regenerator via the nozzles of the pipes in annular shapes. The nozzles are
arranged
toward various directions. The gas stripping medium may be water vapor or
nitrogen, etc.,
preferably water vapor. A regenerated catalyst in the regenerator is stripped
by the gas
stripping medium 13, so that flue gas carried by the regenerated catalyst is
lifted to the
regenerator settling section, thereby the amount of flue gas carried by the
catalyst into the
reactor is reduced.
A cyclone separator 10 is arranged in the regenerator settling section 18 to
separate
the catalyst from flue gas. The top of the regenerator is provided with a flue
gas outlet 19.
The flue gas is discharged out of the regenerator via the outlet 19 after the
catalyst is
separated from the flue gas.
All the pipes in annular shapes (including the feeding annular pipe in the
reactor, the
gas stripping medium annular pipe, as well as the annular pipe which is used
for
introducing the fuel or the gas stripping medium into the regenerator) are as
shown in Fig.
3, and nozzles are arranged on the pipes in annular shapes. Preferably, the
openings of the
nozzles are upward.
Embodiment 5
The dehydrogenation-regeneration device for alkane of Embodiment 4 is used to
17
Date Recue/Date Received 2021-06-23
implement a dehydrogenation reaction and a subsequent aromatization reaction.
The
specific process flow is shown in Fig. 2.
Dehydro2enation reaction
Propane and butane 5 as raw materials were fed in the reactor reaction section
7
through the feed distributor 6 after being preheated, wherein the preheating
temperature is
in a range of 300 DEG C to 550 DEG C, preferably 350 DEG C to 500 DEG C. The
raw
materials are in contact with a dehydrogenation catalyst for reaction, and any
one of
Embodiments 1-3 is selected as the dehydrogenation catalyst. In the
dehydrogenation
reaction process, the reaction temperature is in a range of 500 DEG C to 660
DEG C, the
pressure at the top of the reactor is in a range of 0.1 MPa to 0.5 MPa
(absolute pressure),
and the mass space velocity is in a range of 0.110 to 510.
The oil gas obtained is discharged from the reactor settling section 9 through
the oil
gas outlet 12. The spent catalyst is lifted by the lifting medium 1 to the
spent catalyst riser
pipe 8 and enters in the regenerator regeneration section 17. The air and fuel
15 are fed in
the regenerator through the air and fuel distributor 16 to burn the spent
catalyst for
regeneration, wherein the regeneration temperature is in a range of 600 DEG C
to 750
DEG C. After being stripped by the gas stripping medium 13, the regenerated
catalyst is
delivered to the reactor 7 along the regenerated catalyst delivery pipe 11,
and the flue gas
is discharged from the flue gas outlet 19 on the top of the regenerator
through the cyclone
separator 10.
Aromatization reaction:
After heat exchange, the oil gas obtained in the dehydrogenation reaction is
delivered
in a water washing tower 20 to remove fine catalyst powder in the oil gas.
Water 22
containing the fine catalyst powder is sent to a sedimentation basin, the oil
gas 23 after
being removed from the fine catalyst powder enters a liquid separation tank 25
through a
compressor 24. After oily sewage 26 is discharged, the oil gas 27 and oil 28
are subjected
to heat exchange, and then enter an aromatization reactor 29 together. In the
aromatization
reaction, a conventional aromatization catalyst is adopted; the aromatization
temperature
18
Date Recue/Date Received 2021-06-23
is in a range of 360 DEG C to 440 DEG C; the pressure is in a range of 0.5 MPa
to 1.0
MPa (absolute pressure); and the mass space velocity is in a range of 0.8 h1
to 1.5 h1. The
aromatization catalyst SHY-02 comprises elements Ga and Pt, and a nano ZSM-5
zeolite,
wherein, the content by weight of element Ga is 1.0%, and the content by
weight of
element Pt is 0.1%.
The oil gas 30 obtained in aromatization process is subjected to heat
exchange, and
then flows in a liquid separation tank 31 to obtain liquid-phase components
and gas-phase
components by gas and liquid separation. The liquid-phase components are
pumped into
an absorption and desorption tower 32 by using a pump, and the gas-phase
components
flow in an air compressor 24, and then is delivered in the absorption and
desorption tower
32 after being compressed to 2 MPa. A part of naphtha 39 is used as absorbent
oil, dry gas
34 is discharged from the top of the absorption and desorption tower, and
absorbent oil 33
(naphtha rich in aromatic hydrocarbons) is discharged from the bottom of the
absorption
and desorption tower and enters a stabilization tower 35. The naphtha 39 is in
the bottom
of the stabilization tower, a part of the naphtha 39 is returned to the
absorption and
desorption tower 32 as absorbent oil, and another part is used as a product
discharged from
the device. The product at the top of the stabilization tower flows in a
liquid separation
tank 36 for separating liquid-phase components from gas-phase components.
Propane and
butane 38 in the gas-phase components are recycled back to the dehydrogenation
reactor 7
for the next cycle.
Aromatic hydrocarbons are prepared in combination with the aromatization
reaction
preparation process of Embodiment 5 below.
Experimental example 1:
The composition of raw materials is shown in Table 1. In the dehydrogenation
reaction, the temperature is 580 DEG C; the catalyst prepared in Embodiment 1
is used as
a dehydrogenation catalyst; the pressure at the top of the reactor is 0.18 MPa
(absolute
pressure); the mass space velocity is 3.0 h1. The product distribution after
the
dehydrogenation reaction in the dehydrogenation reactor 7 is listed in Table
2.
19
Date Recue/Date Received 2021-06-23
The oil gas obtained in the dehydrogenation reaction is fed in the
aromatization
reactor after dust removal, compression, and heat exchange. In the
aromatization reaction,
the temperature is 380 DEG C, the pressure is 0.8 MPa (absolute pressure), and
the mass
space velocity is 1.2 h1. The aromatization catalyst SHY-02 comprises elements
Ga and Pt,
and a nano ZSM-5 zeolite. In aromatization catalyst SHY-02, the content by
weight of
element Ga is 1.0%, the content by weight of element Pt is 0.1%. The
aromatization
product distribution is shown in Tables 3-4.
Experimental example 2:
The composition of raw materials is shown in Table 1. In the dehydrogenation
reaction, the catalyst prepared in Embodiment 1 is used as a dehydrogenation
catalyst; the
temperature of the dehydrogenation reaction is 600 DEG C; the pressure at the
top of the
reactor is 0.15 MPa (absolute pressure); the mass space velocity is 2.5 h1.
The product
distribution after the reaction in the dehydrogenation reactor 7 is listed in
Table 2.
The oil gas obtained in the dehydrogenation reaction is fed in the
aromatization
reactor after dust removal, compression, and heat exchange. In the
aromatization reaction,
the temperature is 400 DEG C, the pressure is 0.7 MPa (absolute pressure), and
the mass
space velocity is 1.1 h1. The aromatization catalyst SHY-02 comprises elements
Ga and Pt,
and a nano ZSM-5 zeolite. In aromatization catalyst SHY-02, the content by
weight of
element Ga is 1.0%, and the content by weight of element Pt is 0.1%. The
aromatization
product distribution is shown in Tables 3-4.
Experimental example 3: 100% propane is used as a raw material. In the
dehydrogenation reaction, the catalyst prepared in Embodiment 1 is used as a
dehydrogenation catalyst; the temperature of the dehydrogenation reaction is
600 DEG C;
the pressure at the top of the reactor is 0.2 MPa (absolute pressure); and the
mass space
velocity is 3.5 h1. The product distribution after the reaction in the
dehydrogenation
reactor 7 is listed in Table 6.
The oil gas obtained in the dehydrogenation reaction is fed in the
aromatization
reactor after dust removal, compression, and heat exchange. In the
aromatization reaction,
Date Recue/Date Received 2021-06-23
the temperature is 380 DEG C, the pressure is 0.9 MPa (absolute pressure), and
the mass
space velocity is 1.3 111. The aromatization catalyst SHY-02 comprises
elements Ga and Pt,
and a nano ZSM-5 zeolite. In aromatization catalyst SHY-02, the content by
weight of
element Ga is 1.0%, and the content by weight of element Pt is 0.1%. The
aromatization
product distribution is shown in Tables 7-8.
Experimental example 4: The composition of raw materials is shown in Table 10.
In
the dehydrogenation reaction, the catalyst prepared in Embodiment 1 is used as
a
dehydrogenation catalyst; the temperature of the dehydrogenation reaction is
580 DEG C;
the pressure at the top of the reactor is 0.15 MPa (absolute pressure); and
the mass space
velocity is 3.0 111. The product distribution after the reaction in the
dehydrogenation
reactor 7 is listed in Table 6.
The oil gas obtained in the dehydrogenation reaction is fed in the
aromatization
reactor after dust removal, compression, and heat exchange. In the
aromatization reaction,
the temperature is 400 DEG C, the pressure is 0.8 MPa (absolute pressure), and
the mass
space velocity is 1.210. The aromatization catalyst SHY-02 comprises elements
Ga and Pt,
and a nano ZSM-5 zeolite. In aromatization catalyst SHY-02, the content by
weight of
element Ga is 1.0%, and the content by weight of element Pt is 0.1%. The
aromatization
product distribution is shown in Tables 7-8.
Table 1 Composition of Raw Materials (wt%)
No. Components Content
1 Ethane 4.83
2 Propane 38.98
3 Iso-butane 24.03
4 N-butane 27.92
5 Cis-2-butene 0.39
6 Iso-pentane 2.70
7 N-pentane 1.15
21
Date Recue/Date Received 2021-06-23
8 Sum 100.00
Table 2 Dehydrogenation Reactor Product Distribution (wt%)
Components Experimental Example 1 Experimental
Example 2
112 1.31 1.46
Methane 1.22 1.39
Ethane 5.18 5.08
Ethylene 1.43 1.72
Propane 27.28 26.17
Propylene 12.23 13.30
I so-butane 11.66 9.93
N-butane 15.52 14.21
Trans-2-butene 3.16 3.51
1-butene 2.52 2.80
I so-butene 11.54 13.22
Cis-2-butene 2.32 2.57
Butadiene 0.63 0.69
I so-pentane 1.23 1.25
N-pentane 0.63 0.65
C6+ 0.56 0.62
Coke 1.21 1.42
Table 3 Aromatization Reaction Product Distribution (wt%)
Components Embodiment 1 Embodiment 2
Dry Gas 3.94 1.80
Propane 32.24 27.93
Propylene 0.20 0.17
I so-butane 19.21 21.87
22
Date Recue/Date Received 2021-06-23
N-butane 15.10 15.75
Butene 0.26 0.27
Liquid Yield of C(>5): 29.05 31.41
Table 4 Composition of Aromatization Reaction Liquid Product Family (wt%)
Aroma
Com
Iso-alkan Cycloal Cyclool tic
pone N-alkane N-olefin Iso-
olefin Sum
e kane efin Hydro
nts
carbon
Embodiment 1
C5 8.06 20.37 0.98 0.00 0.14 0.17 0.00 29.73
C6 1.48 5.31 0.77 0.00 0.00 0.00 4.59 12.15
C7 0.22 2.27 1.41 0.00 0.00 0.00 17.28 21.17
C8 0.04 0.82 1.48 0.00 0.00 0.00 27.58 29.92
C9 0.10 0.22 0.54 0.00 0.00 0.00 5.98 6.83
C10 0.10 0.10 0.00 0.00 0.00 0.00 0.00 0.19
Sum 9.99 29.08 5.18 0.00 0.14 0.17 55.43
100.00
Embodiment 2
C5 9.21 22.80 0.73 0.00 0.16 0.16 0.00 33.05
C6 1.62 6.15 0.89 0.00 0.00 0.00 4.36 13.02
C7 0.22 2.24 1.40 0.00 0.00 0.00 16.27 20.13
C8 0.03 0.72 1.28 0.00 0.00 0.00 24.65 26.68
C9 0.10 0.16 0.39 0.00 0.00 0.00 6.34 6.99
C10 0.00 0.12 0.00 0.00 0.00 0.00 0.00 0.12
Sum 11.18 32.19 4.69 0.00 0.16 0.16 51.63
100.00
Table 5 Dehydrogenation Reactor Product Distribution (wt%)
Components Embodiment 3 Embodiment 4
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Date Recue/Date Received 2021-06-23
112 1.4 1.18
Methane 1.12 1.46
Ethane 1.18 1.18
Ethylene 0.73 0.51
Propane 61.28 0.81
Propylene 33 2.04
Iso-butane 0 27.05
N-butane 0 24.65
Trans-2-butene 0 4.40
1-butene 0 4.20
Iso-butene 0.36 25.55
Cis-2-butene 0 3.17
Butadiene 0 0.92
Iso-pentane 0.02 0.27
N-pentane 0.01 0.16
C6+ 0.08 0.99
Coke 0.82 1.47
Table 6 Aromatization Reaction Product Distribution (wt%)
Components Embodiment 3 Embodiment 4
Dry Gas 1.57 1.73
Propane 21.43 30.22
Propylene 0.02
Iso-butane 0.89 18.93
N-butane 0.70 16.31
Butene 0.06
Liquid Yield of C(>5): 25.41 32.73
24
Date Recue/Date Received 2021-06-23
Table 7 Composition of Aromatization Reaction Liquid Product Family (wt%)
Aroma
Com
Iso-alkan Cycloal Cyclool tic
pone N-alkane N-olefin Iso-
olefin Sum
e kane efin Hydro
nts
carbon
Embodiment 3
C5 12.48 21.83 0.84 0.00 0.09 0.15 0.00 35.39
C6 2.37 4.27 0.69 0.00 0.00 0.00 5.04 12.37
C7 1.37 3.01 1.39 0.00 0.00 0.00 15.21 20.98
C8 0.09 0.58 1.56 0.00 0.00 0.00 23.69 25.92
C9 0.30 0.48 0.31 0.00 0.00 0.00 3.38 4.47
C10 0.20 0.67 0.00 0.00 0.00 0.00 0.00 0.87
Sum 16.81 30.84 4.79 0.00 0.09 0.15 47.32 100
Embodiment 4
C5 11.66 23.45 0.96 0.00 0.13 0.16 0.00 36.36
C6 2.43 6.21 0.86 0.00 0.00 0.00 3.7 13.2
C7 0.21 2.45 1.43 0.00 0.00 0.00 14.77 18.86
C8 0.03 0.94 1.55 0.00 0.00 0.00 23.15 25.67
C9 0.10 0.23 0.43 0.00 0.00 0.00 4.89 5.65
C10 0.10 0.16 0.00 0.00 0.00 0.00 0.00 0.26
Sum 14.53 33.44 5.23 0.00 0.13 0.16 46.51 100
Table 8 Composition of Raw Materials (wt%)
Components Embodiment 4
Iso-butane 56.52
N-butane 43.48
Date Recue/Date Received 2021-06-23
