Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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CATALYST COATING AND PROCESS FOR THE CONVERSION OF OXYGENATES TO
OLEFINS
The present invention relates to a catalyst in the form of a coated support
substrate for the
conversion of oxygenates to olefins, and to a process for preparation thereof.
The present
invention further relates to a process for conversion of oxygenates to
olefins, especially using
the inventive coated support substrate as a catalyst, and to the use of a
catalyst according to
the present invention in specific catalytic processes.
INTRODUCTION
In view of increasing scarcity of mineral oil deposits which serve as starting
material for
preparation of lower hydrocarbons and derivatives thereof, alternative
processes for preparing
such commodity chemicals are becoming increasingly important. In alternative
processes for
obtaining lower hydrocarbons and derivatives thereof, specific catalysts are
frequently used in
order to obtain lower hydrocarbons and derivatives thereof, such as
unsaturated lower
hydrocarbons in particular, with maximum selectivity from other raw materials
and/or chemicals.
In this context, important processes include those in which methanol as a
starting chemical is
subjected to a catalytic conversion, which generally gives rise to a mixture
of olefins, paraffins
and aromatics.
In the case of such catalytic conversions, it is a particular challenge to
refine the catalysts used
therein, and also the process regime and parameters thereof, in such a way
that a few very
specific products form with maximum selectivity in the catalytic conversion.
Thus, these
processes are named particularly according to the products which are obtained
in the main. In
the past few decades, particular significance has been gained by those
processes which enable
the conversion of methanol to olefins and are accordingly characterized as
methanol-to-olefin
processes (MTO process for methanol to olefins). For this purpose, there has
been
development particularly of catalysts and processes which convert methanol via
the dimethyl
ether intermediate to mixtures whose main constituents are ethene and propene.
Antia et at. in Ind. Eng. Chem. Res. 1995, 34, pages 140-147 describes the
coating of a support
substrate with ZSM-5 and the use thereof in a methanol-to-gasoline process
(MTG process).
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US 4,692,423 relates to a process for preparing a supported zeolitic catalyst
by applying a
mixture of a zeolite in a polymerizable solvent, for example tetrahydrofuran,
to a porous support
substrate, and the latter may consist of organic or inorganic material.
lvanova et al. in J. Phys. Chem. C 2007, 111, pages 4368-4374 relates to a
foamed molding
and to an extrudate composed of 13-silicon carbide, to each of which a ZSM-5
coating is applied,
and to the use of such a coated foam body and extrudate in methanol-to-olefin
processes (MTO
processes). Compared to the use of the pulverulent zeolite per se, an
improvement in the
catalytic activity/selectivity is observed here, the coated catalysts having a
higher stability with
respect to deactivation by coking.
Patcas, F. C. in Journal of Catalysis 2005, 231, pages 194-200, describes
ceramic foams
coated with ZSM-5 zeolite and the use thereof in methanol-to-olefin processes.
More
particularly, it is stated that, in comparison to zeolitic pellets, such
coated ceramic foams should
exhibit an improvement in activity and selectivity. At relatively low
temperatures and relatively
high space velocities, however, lower space-time yields are described compared
to the zeolitic
pellets.
WO 98/29519 Al describes nonzeolitic molecular sieves and especially SAPO
supported on
inorganic materials, and the use thereof in methanol-to-olefin processes.
WO 94/25151 Al describes zeolites and especially ZSM-5 supported on monoliths,
and the use
thereof as a molecular sieve in separation processes.
Hammon et al. in Applied Catalysis 1988, 37, pages 155-174 relates to
processes for producing
zeolite extrudates with little to no binder and the use thereof in methanol-to-
olefin processes.
However, Hammon et al. describes the use of extrudates shaped to monoliths as
catalysts as
being particularly disadvantageous due to rapid coking and correspondingly
short service lives.
Li et al. in Catal. Lett. 2009, 129, pages 408-415 relates to a foamed ZSM-5
monolith and to the
use thereof in a methanol-to-olefin process.
DD 238733 Al relates, for example, to a magnesium-doped zeolite and to the use
thereof in the
conversion of methanol to lower olefins, specifically of the carbon number
range 3. McIntosh
et al. in Applied Catalysis 1983, 6, p. 307-314 describes specifically ZSM-5
catalysts and the
use thereof in methanol-to-olefin processes, and the doping thereof with
various metals and
nonmetals, for example magnesium or phosphorus, and the influence thereof on
the yields and
product distribution in the catalytic conversion of methanol.
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US 4,049,573 relates to a catalytic process for conversion of lower alcohols
and ethers thereof,
and especially methanol and dimethyl ether, selectively to a hydrocarbon
mixture with a high
proportion of C2-C3 olefins and monocyclic aromatics and especially para-
xylene, the catalysts
used therein being doped with boron, magnesium and/or phosphorus.
Goryainova et al. in Petroleum Chemistry 2011, vol. 51, no. 3, p. 169-173
describes the catalytic
conversion of dimethyl ether to lower olefins using magnesium-containing
zeolites.
Ciambelli et al. "Acid-base catalysis in the conversion of methanol to olefins
over Mg-modified
ZSM-5 zeolite", Successful Design of Catalysts, Elsevier Science Publishers
B.V., Amsterdam,
1988, p. 239-246 examines the influence of magnesium in the MTO process and
especially in
combination with ZSM-5 zeolite as a catalyst.
Okado et al. in Applied Catalysis 1988, 41, p. 121-135 relates to methanol-to-
olefin processes
using the ZSM-5 catalyst and examines the influence of various alkaline earth
metals with
regard to deactivation of the catalyst during the service life thereof.
Even though some advances have been achieved in the prior art with regard to
the selectivities
and/or activities of the catalysts by alterations to their composition and/or
their configuration,
especially also in methanol-to-olefin processes, there is still a considerable
need for new
catalysts and processes which, as well as new and/or improved selectivities,
also have better
resistance to any deactivation in such processes. This is especially true of
those improvements
which can lead to lower coking of the catalyst, in order thus to be able to
enable a higher
efficiency of existing and new processes.
DETAILED DESCRIPTION
It is thus an object of the present invention to provide an improved catalyst,
especially for the
conversion of oxygenates to olefins, which enables a longer service life of
the catalyst with
comparable space velocity and conversion of oxygenates. In this context, it
was a particular
object of the present invention to bring about improvements with regard to the
coking of the
catalyst which, for example in methanol-to-olefin processes, decides the
service lives of a
catalyst before regeneration of the catalyst is required, in order to achieve
the desired selectivity
and/or an adequate space-time yield.
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It has been found that, surprisingly, a catalyst for the conversion of
oxygenates to olefins, which
comprises a support substrate and a layer applied to the substrate, the
catalytically active layer
comprising one or more zeolites of the MFI, MEL and/or MVVVV structure type,
each of which
comprise one or more alkaline earth metals, not only possesses a considerably
improved
service life but also a surprisingly high selectivity for C3- and C4-olefins.
More particularly, it has
also been found that, unexpectedly, the specific combination of the doping of
one or more
zeolites of the MFI, MEL and/or MWW structure type with one or more alkaline
earth metals in
combination with a configuration of the catalyst as a support substrate coated
with the one or
more zeolites results both in an unexpected improvement in the resistance of
the catalyst to
deactivation during the use thereof in a catalytic process and a surprisingly
high olefin selectivity
in the case of use of the catalyst for conversion of oxygenates.
The present invention thus relates to a catalyst for the conversion of
oxygenates to olefins,
comprising
- a support substrate and
- a layer applied to the substrate,
wherein the layer comprises one or more zeolites of the MFI, MEL and/or MVVW
structure type,
the one or more zeolites comprising one or more alkaline earth metals.
With regard to the support substrate used in the inventive catalyst, there is
in principle no
restriction whatsoever with regard to the form thereof. It is thus possible in
principle to select
any conceivable possible form for the support substrate, provided that it is
suitable for being at
least partially coated with a layer of the one or more zeolites of the MFI,
MEL and/or MVVW
structure type. According to the present invention, however, it is preferred
that the form of the
support substrate is selected from the group consisting of granules, pellets,
meshes, rings,
spheres, cylinders, hollow cylinders and mixtures and/or combinations of two
or more thereof.
With regard to the preferred mixtures, these relate preferably to those forms
of the support
substrate which are commonly used for production of beds, this relating
especially to the
preferred forms of the support substrate selected from the group of the
granules, pellets,
meshes, rings, spheres, cylinders and hollow cylinders. On the other hand,
with regard to the
combinations of forms of the support substrate according to the present
invention, preference is
given to those combinations of beds and monoliths where the beds preferably
comprise support
substrates selected from the group consisting of granules, pellets, meshes,
rings, spheres,
cylinders, hollow cylinders and mixtures of two or more thereof. More
particularly, such
combinations of beds and monoliths relate to preferred forms of the catalyst
in which a
sequence of one or more monoliths and one or more beds is present, in which
the bed(s) and
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monolith(s) form individual zones of the catalyst. Alternatively, however,
preference is also given
to embodiments of the inventive catalyst which comprise combinations of
monoliths as the form
of the support substrate, especially combinations of monoliths according to
the particular or
preferred embodiments as described in the present application. In particularly
preferred
embodiments of the present invention, the support substrate consists of one or
more monoliths,
and, in the case of use of a plurality of monoliths, a sequence and/or a
succession of individual
monoliths or plural monoliths arranged alongside one another at least in pairs
is preferably
present in the catalyst.
Thus, according to the present invention, preference is given to embodiments
of the catalyst
for the conversion of oxygenates to olefins in which the form of the support
substrate is
selected from the group consisting of granules, pellets, meshes, rings,
spheres, cylinders,
hollow cylinders, monoliths and mixtures and/or combinations of two or more
thereof, the
support substrate preferably being one or more monoliths.
With regard to the one or more monoliths which are preferably present as the
support substrate
in the inventive catalyst, there is again in principle no restriction with
regard to the form that the
one or more monoliths may take. According to the present invention, preference
is given to
monoliths selected from the group consisting of honeycombs, braids, foams and
combinations
of two or more thereof, and the one or more monoliths further preferably
comprise one or more
honeycombs and/or braids. More preferably, according to the present invention,
the one or more
monoliths which are preferably used as the support substrate are in honeycomb
form.
Thus, according to the present invention, preference is further given to
embodiments of the
catalyst for the conversion of oxygenates to olefins in which the one or more
monoliths as the
preferred support substrate are selected from the group consisting of
honeycombs, braids,
foams and combinations of two or more thereof, the one or more monoliths
preferably being in
honeycomb form.
In the preferred embodiments which comprise one or more monoliths in honeycomb
form, there
are no particular restrictions whatsoever with regard to the honeycomb form,
provided that it is
suitable for being at least partially coated with the one or more zeolites of
the MFI, MEL and/or
MVVW structure type. In particularly preferred embodiments, the honeycomb
consists of a
multitude of channels which run parallel to one another and which are divided
from one another
by the walls of the monolith, and the shape of the channels and/or preferably
the thickness of
the walls of the monolith which divide the channels from one another, up to a
certain tolerance,
are preferably the same both in terms of the shape of the channels and with
regard to the wall
thickness, the latter typically resulting from the material used for
production of the monolith or
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the mode of production of the honeycomb or the honeycomb form. For example,
preference is
given to channels which have an angular shape, preferably the shape of a
regular polyhedron
having three or more vertices, preferably having three, four or six vertices
and more preferably
having four vertices. With regard to the dimensions of the channels in the
preferred
embodiments of the monoliths in honeycomb form, there is no restriction in
principle, provided
that the selected dimensions allow at least partial coating of the monolith in
honeycomb form as
the support substrate in the inventive catalyst with the one or more zeolites
of the MFI, MEL
and/or MWW structure type.
Thus, according to the present invention, it is possible to use, for example,
monoliths in
honeycomb form having 62 to 186 channels per square centimeter (400 to 1200
cpsi = cells per
square inch), preference being given to monoliths in honeycomb form having 78
to 171
channels per square centimeter (500 to 1100 cpsi), further preference to those
having 93 to 163
(600 to 1050 cpsi), further preference to those having 109 to 155 (700 to 1000
cpsi), further
preference to those having 124 to 147 (800 to 950 cpsi) and further preference
to those having
132 to 144 (850 to 930 cpsi). In particularly preferred embodiments of the
present invention,
according to which the support substrate comprises one or more monoliths in
honeycomb form,
those having 136 to 141 channels per square centimeter (880 to 910 cpsi) are
used. In
alternative embodiments of the present invention, and especially in preferred
embodiments in
which the layer applied to the substrate in the inventive catalyst further
comprises a binder,
monoliths with honeycomb are used having 8 to 124 channels per square
centimeter (50 to
800 cpsi), preference being given to monoliths with honeycomb form having 23
to 109 channels
per square centimeter (150 to 700 cpsi), further preferably those having 31 to
93 (200 to
600 cpsi), further preferably those having 39 to 85 (250 to 550 cpsi) and
further preferably those
having 47 to 78 (300 to 500 cpsi). In the alternative embodiments of the
present invention,
particular preference is given to embodiments in which the one or more
monoliths with
honeycomb form have 54 to 70 channels per square centimeter (350 to 450 cpsi).
In alternative embodiments of the present invention which use one or more
monoliths as the
support substrate in the catalyst, no substrate foams are present therein.
Thus, preference is
likewise given to embodiments of the catalyst in which the support substrate
does not comprise
any foams and more particularly does not comprise any foams as a monolith.
With regard to the substance of which the support substrate consists, and
especially the beds
and/or monoliths present therein, according to the present invention, there
are no restrictions
whatsoever in this regard, provided that it is suitable for being at least
partially coated with the
one or more zeolites of the MFI, MEL and/or MWW structure type. Thus, it is
possible in
principle to use any suitable material and/or any material composite as the
substance for the
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support substrate, preference being given to using those materials which have
high thermal
stability and/or are inert to a high degree with regard to the chemical
reactivity thereof. Thus,
preference is given to using ceramic and/or metallic substances and composite
materials of
ceramic and/or metallic substances as the support substrate in the inventive
catalyst,
preference being given to using ceramic substances as the support substrate.
With regard to
the preferred ceramic substances, preference is given to using one or more of
these substances
selected from the group consisting of alumina, silica, silicates,
aluminosilicates, silicon carbide,
cordierite, mullite, zirconium, spinels, magnesia, titania and mixtures of two
or more thereof. In a
particularly preferred embodiment of the present invention, the ceramic
substances preferably
used for the support substrate are selected from the group consisting of a-
alumina, silicon
carbide, cordierite and mixtures of two or more thereof. In particularly
preferred embodiments,
the support substrate comprises cordierite, the support substrate further
preferably being a
cordierite substrate.
Thus, according to the present invention, preference is given to embodiments
of the catalyst
for the conversion of oxygenates to olefins in which the support substrate
comprises
ceramic and/or metallic substances, preferably ceramic substances, further
preferably one
or more substances selected from the group consisting of alumina, silica,
silicates,
aluminosilicates, silicon carbide, cordierite, mullite, zirconium, spinels,
magnesia, titania and
mixtures of two or more thereof, preferably from the group consisting of alpha-
alumina,
silicon carbide, cordierite and mixtures of two or more thereof, the support
substrate more
preferably being a cordierite substrate.
With regard to the one or more zeolites present in the catalyst, according to
the present
invention, there are no restrictions whatsoever either with regard to the type
or with regard to
the number of zeolites which can be used herein, provided that they are
zeolites of one or more
of the MFI, MEL and MWW structure types. If one or more of the zeolites
present in the catalyst
are of the MWW structure type, there is again no restriction whatsoever with
regard to the type
and/or number of MWW zeolites which can be used according to the present
invention. Thus,
these may be selected, for example, from the group of zeolites of the MWW
structure type
consisting of MCM-22, MCM-36, [Ga-Si-O]MVVW, [Ti-Si-0]-MWW, ERB-1, ITQ-1, PSH-
3, SSZ-
25 and mixtures of two or more thereof, preference being given to the use of
zeolites of the
MWW structure type which are suitable for the conversion of oxygenates to
olefins, especially
MCM-22 and/or MCM-36.
The same applies correspondingly to the zeolites of the MEL structure type
which can be used
according to the present invention in the catalyst, these being selected, for
example, from the
group consisting of ZSM-11, [Si-B-0]-MEL, boron-D (MFI/MEL mixed crystal),
boralite D, SSZ-
8
46, silicalite 2, TS-2 and mixtures of two or more thereof. Here too,
preference is given to using
those zeolites of the MEL structure type which are suitable for the conversion
of oxygenates to
olefins, especially [Si-B-01-MEL.
According to the present invention, however, especially zeolites of the MFI
structure type are used
in the inventive catalyst for the conversion of oxygenates to olefins. With
regard to these preferred
embodiments of the present invention, there is likewise no restriction with
regard to the type and/or
number of the zeolites of this structure type used, the one or more zeolites
of the MFI structure
type which are used in the inventive catalyst preferably being selected from
the group consisting
of ZSM-5, ZBM-10, [As-Si-0]-MFI, [Fe-Si-0]-MFI, [Ga-Si-0]-MFI, AMS-1B, AZ-1,
boron-C,
boralite C, encilite, FZ-1, LZ-105, monoclinic H-ZSM-5, mutinaite, NU-4, NU-5,
silicalite, TS-1,
TSZ, TSZ-III, TZ-01, USC-4, USI-108, ZBH, ZKQ-1B, ZMQ-TB and mixtures of two
or more
thereof. Further preferably, according to the present invention, the catalyst
comprises ZSM-5
and/or ZBM-10 as the zeolite of the MFI structure type, particular preference
being given to using
ZSM-5 as the zeolite. With regard to the zeolitic material ZBM-10 and the
preparation thereof,
reference is made, for example, to EP 0 007 081 Al and to EP 0 034 727 A2.
Thus, according to the present invention, preference is given to embodiments
of the catalyst for
the conversion of oxygenates to olefins in which the one or more zeolites are
of the MFI structure
type, and are preferably selected from the group consisting of ZSM-5, ZBM-10,
[As-Si-0]-MFI,
[Fe-Si-0]-MFI, [Ga-Si-0]-MFI, AMS-1B, AZ-1, boron-C, boralite C, encilite, FZ-
1, LZ-105,
monoclinic H-ZSM-5, mutinaite, NU-4, NU-5, silicalite, TS-1, TSZ, TSZ-III, TZ-
01, USC-4,
USI-108, ZBH, ZKQ-1B, ZMQ-TB and mixtures of two or more thereof, further
preferably from.
the group consisting of ZSM-5, ZBM-10 and mixtures thereof, the zeolite of the
MFI structure
type preferably being ZSM-5.
In a preferred embodiment of the present invention, the catalyst does not
comprise any
significant amounts of one or more nonzeolitic materials and especially does
not comprise any
significant amounts of one or more aluminosilicophosphates (SAP0s). In the
context of the
present invention, the catalyst is essentially free of or does not comprise
any significant amounts
of a specific material in cases in which this specific material is present in
the catalyst in an
amount of 0.1% by weight or less based on 100% by weight of the total amount
and the one or
more zeolites of the MFI, MEL and/or MVVVV structure type, preferably in an
amount of 0.05%
by weight or less, further preferably of 0.001% by weight or less, further
preferably of 0.0005%
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by weight or less and further preferably in an amount of 0.0001% by weight or
less. A specific
material in the context of the present invention particularly denotes a
particular element or a
particular combination of elements, a particular substance or a particular
substance mixture,
and also combinations and/or mixtures of two or more thereof.
The aluminosilicophosphates (SAP0s) in the context of the present invention
include especially
the SAPO materials SAPO-11, SAPO-47, SAPO-40, SAPO-43, SAPO-5, SAPO-31, SAPO-
34,
SAPO-37, SAPO-35, SAPO-42, SAPO-56, SAPO-18, SAPO-41, SAP0-39 and CFSAPO-1A.
According to the present invention, the one or more zeolites of the MFI, MEL
and/or MWW
structure type comprises one or more alkaline earth metals. In general,
according to the present
invention, there is no restriction whatsoever either with regard to the type
and/or the number of
alkaline earth metals present in the one or more zeolites, or with regard to
the manner in which
they are present in the one or more zeolites. Thus, the one or more zeolites
may comprise one
or more alkaline earth metals selected, for example, from the group consisting
of magnesium,
calcium, strontium, barium and combinations of two or more thereof. According
to the present
invention, the one or more alkaline earth metals, however, are preferably
selected from the
group consisting of magnesium, calcium, strontium and combinations of two or
more thereof,
and, in particularly preferred embodiments of the inventive catalyst, the
alkaline earth metal is
magnesium. In alternatively preferred embodiments of the present invention,
the catalyst does
not comprise any, or any significant amounts of, calcium and/or strontium.
Thus, according to the present invention, preference is given to embodiments
of the catalyst
for the conversion of oxygenates to olefins in which the alkaline earth metals
present in the
one or more zeolites of the MFI, MEL and/or MWW structure type are selected
from the group
consisting of Mg, Ca, Sr, Ba and combinations of two or more thereof,
preferably consisting of
Mg, Ca, Sr and combinations of two or more thereof, the alkaline earth metal
more preferably
being Mg.
With regard to the manner in which the one or more alkaline earth metals are
present in the one
or more zeolites in the catalyst, these may in principle be present in the
micropores of the one
or more zeolites and/or as a constituent of the zeolitic skeleton, especially
at least partly in
isomorphic substitution for an element in the zeolite skeleton, preferably for
silicon and/or
aluminum as a constituent of the zeolite skeleton and more preferably at least
partly in
isomorphic substitution for aluminum. With regard to the presence of the one
or more alkaline
earth metals in the micropores of the one or more zeolites, these may be
present as a separate
compound, for example as a salt and/or oxide therein, and/or as a positive
counterion to the
zeolite skeleton. According to the present invention, the one or more alkaline
earth metals are
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present at least partly in the pores and preferably in the micropores of the
one or more zeolites,
and, further preferably, the one or more alkaline earth metals are present
therein at least partly
as the counterion of the zeolite skeleton, as can arise, for example, in the
course of production
of the one or more zeolites in the presence of the one or more alkaline earth
metals and/or can
be brought about by performance of an ion exchange with the one or more
alkaline earth metals
in the zeolite already produced.
With regard to the amount of the one or more alkaline earth metals, as already
noted above,
there are no particular restrictions according to the present invention with
regard to the amount
in which they are present in the one or more zeolites. It is thus possible in
principle for any
possible amount of the one or more alkaline earth metals to be present in the
one or more
zeolites, for example in a total amount of the one or more alkaline earth
metals of 0.1-20% by
weight based on the total amount of the one or more zeolites. According to the
present
invention, however, it is preferred that the one or more alkaline earth metals
are present in a
total amount in the range of 0.5-15% by weight based on 100% by weight of the
total amount of
the one or more zeolites, further preferably of 1-10% by weight, further
preferably of 2-7% by
weight, further preferably of 3-5% by weight and further preferably of 3.5-
4.5% by weight. In
particularly preferred embodiments of the present invention, the one or more
alkaline earth
metals are present in a total amount of 3.8-4.2% by weight in the one or more
zeolites. For all of
the above percentages by weight for alkaline earth metal in the one or more
zeolites, these are
calculated proceeding from the one or more alkaline earth metals as the metal.
Thus, according to the present invention, preference is given to embodiments
of the catalyst
for the conversion of oxygenates to olefins in which the one or more zeolites
of the MFI,
MEL and/or MWW structure type comprise the one or more alkaline earth metals
in a total
amount in the range from 0.1 to 20% by weight, preferably from 0.5 to 15% by
weight,
further preferably from 1 to 10% by weight, further preferably from 2 to 7% by
weight, further
preferably from 3 to 5% by weight, further preferably from 3.5 to 4.5% by
weight, and further
preferably in the range from 3.8 to 4.2% by weight, based in each case on the
total amount
of the one or more zeolites of the MFI, MEL and/or MWW structure type and
calculated as
the metal.
With regard to the components which may be present in the layer applied to the
substrate in the
inventive catalyst, there are no restrictions, provided that the catalyst is
suitable for the
conversion of at least one oxygenate to at least one olefin. Thus, in
particular embodiments, the
layer applied to the substrate may consist of the one or more zeolites of the
MFI, MEL and/or
MWW structure type comprising one or more alkaline earth metals. In further
embodiments of
the inventive catalyst, the layer applied to the substrate comprises one or
more further
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components to the zeolites mentioned. With regard to the additional components
to the one or
more zeolites of the MFI, MEL and/or MWW structure type, there are no
restrictions whatsoever,
and so the layer applied to the substrate may comprise, for example, further
catalytically active
components, cocatalysts, fillers, support substances and/or binders, and
combinations of two or
more thereof. In preferred embodiments, the layer applied to the substrate
further comprises a
binder. In these preferred embodiments, any suitable binder may be present in
the layer, and so
one or more additional components which may be present in the layer applied
act as binders
and especially improve the coherence of the further components and especially
of the one or
more zeolites. Thus, for example, one or more components may be present in the
layer as
binders, selected from the group consisting of SiO2, A1203, TiO2, ZrO2, MgO,
clay minerals and
mixtures of two or more thereof, the layer in a particularly preferred
embodiment comprising
SiO2 as a binder in addition to the one or more zeolites of the MFI, MEL
and/or MWW structure
type.
With regard to the amount in which the one or more zeolites of the MFI, MEL
and/or MWW
structure type has been applied to the support substrate in the catalyst
according to the present
invention, there is in principle no restriction whatsoever, provided that a
layer comprising the
one or more zeolites can be formed at least partially on the support
substrate. Thus, the
inventive catalysts comprise, for example, the one or more zeolites of the
MFI, MEL and/or
MWW structure type in a total loading of 0.005-1 g/cm3. According to the
present invention, the
term "loading" represents the amount of applied components of a layer in grams
of dry
substance per unit total volume of the support substrate. The volume relates
here to the volume
of the coated support substrate, and this in the case of bodies and forms
comprising hollow
bodies and/or recesses also comprises those cavities and recesses. In an
alternative definition
according to the present invention, the volume in the case of the loading of
the support
substrate, in embodiments comprising beds, is based on the respective volume
of the bed
including the intermediate spaces and cavities present therein. In preferred
embodiments of the
present invention, the catalyst comprises the one or more zeolites of the MFI,
MEL and/or
MWW structure type in a total loading of 0.01-0.5 g/cm3 based on the volume of
the coated
support substrate and especially on the volume thereof according to the
aforementioned
particular and preferred definitions, further preferably in a total loading of
0.02-0.2 g/cm3, further
preferably of 0.04-0.1 g/cm3, further preferably of 0.055-0.08 g/cm3 and
further preferably of
0.065-0.075 g/cm3. In particularly preferred embodiments of the present
invention, the catalyst
comprises the one or more zeolites of the MFI, MEL and/or MWW structure type
in a total
loading of 0.07-0.072 g/cm3 based on the volume of the coated support
substrate according to
the particular and preferred definitions of the present application.
CA 02877796 2014-12-23
12
Thus, according to the present invention, preference is given to embodiments
of the catalyst
for the conversion of oxygenates to olefins in which the catalyst comprises
the one or more
zeolites of the MFI, MEL and/or MWW structure type in a total loading of 0.005
to 1 g/cm3 based
on the volume of the coated support substrate, preferably in a total loading
of 0.01 to 0.5 g/cm3,
further preferably of 0.02 to 0.2 g/cm3, further preferably of 0.04 to 0.1
g/cm3, further preferably
of 0.055 to 0.08 g/cm3, further preferably of 0.065 to 0.075 g/cm3, and
further preferably in a
total loading of 0.07 to 0.072 g/cm3.
In alternative embodiments of the present invention which are further
preferred, and especially
in preferred embodiments in which the layer applied to the substrate in the
inventive catalyst
further comprises a binder, the catalyst for the conversion of oxygenate to
olefins comprises the
one or more zeolites of the MFI, MEL and/or MWW structure type in a total
loading of 0.01 to
0.8 g/cm3 based on the volume of the coated support substrate, preferably in a
total loading of
0.05 to 0.5 g/cm3, further preferably of 0.08 to 0.3 g/cm3, further preferably
of 0.12 to 0.25 g/cm3,
further preferably of 0.15 to 0.23 g/cm3, further preferably of 0.17 to 0.21
g/cm3, and further
preferably in a total loading of 0.18 to 0.2 g/cm3.
The catalyst according to the present invention can be prepared in any
suitable manner,
provided that it comprises one or more zeolites of the MFI, MEL and/or MWW
structure type
which are present in a layer applied to a support substrate according to the
present invention
and especially according to one of the particular and preferred embodiments of
the invention as
described in the present application.
Thus, the present invention also relates to a process for preparing a catalyst
according to the
present invention, and especially according to one of the particular or
preferred embodiments
thereof, comprising
(i) providing the support substrate and the one or more zeolites of the
MFI, MEL
and/or MWW structure type;
(ii) impregnating the one or more zeolites of the MFI, MEL and/or MWW
structure type
with a solution comprising the one or more alkaline earth metals, preferably
by
means of spray impregnation;
(iii) optionally drying the one or more impregnated zeolites obtained in (ii);
(iv) optionally calcining the one or more impregnated zeolites obtained in
(ii) or (iii);
(v) preparing a mixture comprising the one or more impregnated and optionally
dried
and/or calcined zeolites of the MFI, MEL and/or MWW structure type and one or
more solvents;
(vi) homogenizing the mixture obtained in (v);
CA 02877796 2014-12-23
13
(vii) coating the support substrate with the homogenized mixture obtained in
(vi);
(viii) optionally drying the coated support substrate obtained in (vii);
(ix) optionally calcining the coated support substrate obtained in (vii) or
(viii).
With regard to the manner of impregnation in step (ii) of the process
according to the invention,
the impregnation can be performed by any suitable process, for example an
impregnation by
soaking, spray impregnation and/or capillary impregnation. In particularly
preferred
embodiments of the process according to the invention, however, the
impregnation in step (ii) is
achieved by spray impregnation.
In the process according to the invention for preparing the inventive
catalyst, especially in the
particular and preferred embodiments described in the present application,
there is in principle
no restriction whatsoever with regard to the properties and especially the
particle sizes and/or
morphologies of the one or more zeolites of the MFI, MEL and/or MWW structure
type provided
in step (i). According to the particle size of the zeolites provided in step
(i), however, one or
more steps are optionally performed during the process according to the
invention, preferably
after the impregnation in step (ii) or after the preparation of the mixture in
step (v), in order to
bring the one or more zeolites to a preferred particle size. In this
connection, there is at first no
particular restriction with regard to the particle size of the one or more
zeolites, provided that
this is suitable for the performance of the further steps in the process
according to the invention,
especially according to the particular and preferred embodiments of the
present invention, and
the particle size should especially be suitable for performance of the coating
in step (vii), more
particularly depending on the nature and form of the support substrate used
according to the
present invention and especially according to the particular or preferred
embodiments of the
support substrate as described in the present application. Thus, in particular
embodiments of
the process according to the invention, one or more steps are performed after
the impregnation
in step (ii) or after the preparation of the mixture in step (v), preferably
after the preparation of
the mixture in step (v) and more preferably in step (vi) of the homogenizing
of the mixture
obtained in (v), in order to bring the one or more impregnated and optionally
dried and/or
calcined zeolites of the MFI, MEL and/or M1NW structure type to a particle
size D50 in the range
from 0.01 to 200 pm. In further preferred embodiments of the process according
to the
invention, the one or more zeolites, after one or more of the aforementioned
steps, are brought
in one or more steps to a particle size D50 in the range from 0.03 to 150 pm,
further preferably
from 0.05 to 100 pm, further preferably from 0.1 to 50 pm, further preferably
from 0.3 to 30 pm
and even further preferably from 0.4 to 20 pm. In yet further preferred
embodiments of the
process according to the invention, the one or more impregnated and optionally
dried and/or
calcined zeolites, after the preparation of the mixtures in step (v) and
preferably in step (vi) of
CA 02877796 2014-12-23
14
the homogenizing of the mixture obtained in (v), is brought in one or more
steps to a particle
size DOO in the range from 0.5 to 15 pm.
In further embodiments of the process according to the invention which are
preferred, and
especially in preferred embodiments in which a binder is used in the process
according to the
invention, one or more steps are performed after the impregnation in step (ii)
or after the
preparation of the mixture in step (v), preferably after the preparation of
the mixture in step (v)
and more preferably in step (vi) of the homogenizing of the mixture obtained
in step (v), in order
to bring the one or more impregnated and optionally dried and/or calcined
zeolites of the MFI,
MEL and/or MWW structure type to a particle size D90 in the range from 0.5 to
50 pm. In further
preferred embodiments of the process according to the invention, the one or
more zeolites, after
one or more of the aforementioned steps, are brought in one or more steps to a
particle size DgO
in the range from 1 to 30 pm, further preferably from 3 to 20 pm, further
preferably from 5 to
15 pm, and even further preferably from 9 to 11 pm. In yet further preferred
embodiments of the
process according to the invention, the one or more impregnated and optionally
dried and/or
calcined zeolites, after the preparation of the mixture in step (v) and
preferably in step (vi) of the
homogenizing of the mixture obtained in (v), is brought in one or more steps
to a particle size
Dgo in the range from 7 to 13 pm.
With regard to the number of steps and the manner in which the one or more
zeolites are
brought to a particular or preferred particle size DOO and/or DgO, according
to the present
invention, there are no restrictions whatsoever, and so it is possible in
principle to use any
suitable process for this purpose. According to the present invention, the one
or more zeolites,
however, are preferably subjected to one or more grinding steps after one or
more of steps (ii)
and (v), and the one or more zeolites are more preferably brought to one of
the particular or
preferred particle sizes D50 by the operation of homogenizing in step (vi),
especially according to
the particular and preferred embodiments of the present invention.
Thus, according to the present invention, preference is given to embodiments
of the process
for preparing a catalyst according to the present invention, and especially a
catalyst according
to one of the particular or preferred embodiments thereof, in which the
impregnation in step (ii)
or the preparation of the mixture in step (v), preferably the preparation of
the mixture in step (v)
and more preferably in step (vi) of the homogenizing of the mixture obtained
in (v), is followed
by bringing of the one or more impregnated zeolites of the MFI, MEL and/or MWW
structure
type to a particle size Doo in the range from 0.01 to 200 pm, further
preferably from 0.03 to 150
pm, further preferably from 0.05 to 100 pm, further preferably from 0.1 to 50
pm, further
preferably from 0.3 to 30 pm, further preferably from 0.4 to 20 pm, even
further preferably from
0.5 to 15 pm. Accordingly, preference is likewise given in accordance with the
present invention
CA 02877796 2014-12-23
to embodiments of the process for preparing a catalyst, and especially a
catalyst according to
one of the particular or preferred embodiments thereof, in which, after the
impregnation in
step (ii) or after the preparation of the mixture in step (v), preferably
after the preparation of the
mixture in step (v) and more preferably in step (vi) of the homogenizing of
the mixture obtained
in (v), the one or more impregnated zeolites of the MFI, MEL and/or MWW
structure type is
brought to a particle size 090 in the range from 0.5 to 50 pm, further
preferably from 1 to 30 pm,
further preferably from 3 to 20 pm, further preferably from 5 to 15 pm,
further preferably from 9
to 11 pm, and even further preferably from 7 to 13 pm.
According to the present invention, in the process according to the invention,
a drying step is
performed according to step (iii) and/or (viii). With regard to the manner in
which the optional
drying is achieved in one or more of these steps, there is no restriction in
principle, and so the
drying can be performed at any suitable temperature and in any suitable
atmosphere. Thus, the
optional drying can be effected under a protective gas atmosphere or in air,
the optional drying
preferably being effected in air. With regard to the temperature at which the
drying is effected, it
is possible, for example, to select a temperature in the range from 50 to 220
C. According to the
present invention, the optional drying according to step (iii) and/or (viii)
is effected at a
temperature in the range from 70 to 180 C, further preferably from 80 to 150
C, further
preferably from 90 to 130 C and further preferably in the range from 100 to
125 C. In
particularly preferred embodiments of the process according to the invention,
the drying
according to step (iii) and/or (viii) is effected at a temperature in the
range from 110 to 120 C.
With regard to the duration of the one or more optional drying steps,
especially in particular and
preferred embodiments of the process according to the invention, there is no
particular
restriction, provided that drying suitable for the further process steps can
be achieved, for
example after a drying step having a duration of 1 to 50 hours. In particular
embodiments of the
process according to the invention, the optional drying is performed for a
period of 5 to 40 h,
further preferably of 8 to 30 h, further preferably of 10 to 25 h, further
preferably of 12 to 20 h
and still further preferably of 14 to 18 h.
Thus, according to the present invention, preference is given to embodiments
of the process
for preparing a catalyst according to the present invention, and especially a
catalyst according
to one of the particular or preferred embodiments thereof, in which the drying
in (iii) and/or (viii)
is effected at a temperature in the range from 50 to 220 C, preferably from 70
to 180 C, further
preferably from 80 to 150 C, further preferably from 90 to 130 C, further
preferably from 100 to
125 C, and further preferably from 110 to 120 C.
With regard to the optional calcining steps according to the present
invention, the same applies
in principle as with regard to the optional drying steps, and so no particular
restriction exists
CA 02877796 2014-12-23
16
here either, either with regard to the temperature or with regard to the
atmosphere in which the
calcination is performed, and finally also not with regard to the duration of
a calcination
according to the particular and preferred embodiments of the present
invention, provided that
the product of the calcination is an intermediate suitable for being processed
in the further steps
of the process according to the invention to give a catalyst according to the
present invention.
Thus, for example, with regard to the temperature of the optional calcination
in step (iv) and/or
(ix), a temperature in the range from 300 to 850 C may be selected, preference
being given to
selecting a temperature in the range from 350 to 750 C, further preferably
from 400 to 700 C,
further preferably from 450 to 650 C and even further preferably from 480 to
600 C. In yet
further preferred embodiments of the present invention, the calcination in the
optional step (iv)
and/or (ix) is performed at a temperature of 500 to 550 C. With regard to the
atmosphere in
which the optional calcination according to one or more of the aforementioned
steps of the
process according to the invention is performed, this may be either an inert
atmosphere or air,
the optional calcination in step (iv) and/or (ix) preferably being performed
in air. Finally, there is
also no restriction whatsoever with regard to the duration of the calcination
step in the optional
step (iv) and/or (ix), provided that the product of the calcination is
suitable for further use,
especially as an intermediate according to the optional step (iv), in the
process according to the
invention for preparing a catalyst, especially a catalyst according to one of
the particular or
preferred embodiments of the present application. Thus, the duration of the
calcination
according to one or more of the optional calcination steps in (iv) and/or (ix)
may, for example, be
0.5 to 20 hours, preference being given to a duration of Ito 15 h, further
preferably of 2 to 10 h,
further preferably of 3 to 7 h, and particular preference to a duration of 4
to 5 h.
Thus, according to the present invention, preference is given to embodiments
of the process
for preparing a catalyst according to the present invention, and especially a
catalyst according
to one of the particular or preferred embodiments thereof, in which the
calcining in (iv) and/or
(ix) is effected at a temperature in the range from 300 to 850 C, preferably
from 350 to 750 C,
further preferably from 400 to 700 C, further preferably from 450 to 650 C,
further preferably
from 480 to 600 C, and further preferably from 500 to 550 C.
In step (ii) of the process according to the invention, the one or more
zeolites of the MFI, MEL
and/or MWW structure type are first impregnated with a solution comprising one
or more
alkaline earth metals. According to the present invention, there is no
restriction whatsoever in
step (ii) with regard to the type and/or number of solvents used for this
purpose. Thus, it is
possible in principle to use any suitable solvent or solvent mixture in step
(ii), provided that it is
suitable for bringing about a corresponding impregnation of the materials
defined therein,
especially according to one of the particular and preferred embodiments of the
present
invention. This is equally true of the one or more solvents which are used in
step (v) for
CA 02877796 2014-12-23
17
preparation of the mixture defined therein, provided that the one or more
solvents used for this
purpose are suitable for enabling homogenization in step (vi) and the coating
in step (vii). For
example, it is possible in step (ii) and/or (v) to use one or more solvents
selected from the group
consisting of alcohols, water, mixtures of two or more alcohols and mixtures
of water and one or
more alcohols. In preferred embodiments of the present invention, the one or
more solvents
used in (ii) and/or (v) are selected from the group consisting of (Ci-C6)-
alcohols, water, mixtures
of two or more (Ci-C6)-alcohols and mixtures of water and one or more (Ci-C6)-
alcohols, the
one or more solvents further preferably being selected from the group
consisting of (C1-C4)-
alcohols, water, mixtures of two or more (Ci-C4)-alcohols and mixtures of
water and one or
more (Ci-C4)-alcohols. In further preferred embodiments, the one or more
solvents in steps (ii)
and/or (v) are selected from the group consisting of methanol, ethanol, n-
propanol, isopropanol,
water and mixtures of two or more thereof, further preferably from the group
consisting of
methanol, ethanol, water and mixtures of two or more thereof, the solvent even
further
preferably being water, preferably distilled water.
Thus, according to the present invention, preference is given to embodiments
of the process
for preparing a catalyst according to the present invention, and especially a
catalyst according
to one of the particular or preferred embodiments thereof, in which the
solution used in (ii)
and/or the mixture prepared in (v) comprises one or more solvents selected
from the group
consisting of alcohols, water, mixtures of two or more alcohols, and mixtures
of water and one
or more alcohols, preferably from the group consisting of (Ci-C6) alcohols,
water, mixtures of
two or more (C1-C6) alcohols, and mixtures of water and one or more (Ci-C6)
alcohols, further
preferably (Ci-C4) alcohols, water, mixtures of two or more (C1-C4) alcohols,
and mixtures of
water and one or more (C1-04) alcohols, further preferably consisting of
methanol, ethanol, n-
propanol, isopropanol, water and mixtures of two or more thereof, further
preferably consisting
of methanol, ethanol, water and mixtures of two or more thereof, the solvent
further preferably
being water, preferably distilled water.
With regard to the solids concentration of the mixture provided in (v),
according to the present
invention, there are no particular restrictions whatsoever, provided that
homogenizing of the
mixture in step (vi) and the use of the homogenized mixture obtained in (vi)
for the coating in
(vii) are possible. Thus, the solids concentration of the mixture provided in
(v) may, for example,
be in the range of 5-50% by weight, the solids concentration according to the
present invention
preferably being in the range of 10-30% by weight and further preferably in
the range of 15-25%
by weight. In particularly preferred embodiments of the process according to
the invention for
preparing a catalyst, the solids concentration of the mixture provided in (v)
is in the range of 18-
22% by weight.
CA 02877796 2014-12-23
18
Thus, according to the present invention, preference is given to embodiments
of the process for
preparing a catalyst according to the present invention, and especially a
catalyst according to
one of the particular or preferred embodiments thereof, in which the solids
concentration of the
mixture prepared in (v) is in the range from 5 to 50% by weight, preferably
from 10 to 30% by
weight, further preferably from 15 to 25% by weight, and further preferably
from 18 to 22% by
weight.
In further embodiments which are preferred as an alternative, and especially
in preferred
embodiments in which a binder is used in the process according to the
invention, the solids
concentration of the mixture provided in (v) is in the range of 10-70% by
weight, the solids
concentration according to the present invention preferably being in the range
of 20-50% by
weight and further preferably in the range of 30-40% by weight. In
particularly preferred
embodiments of the process according to the invention for preparing a
catalyst, the solids
concentration of the mixture provided in (v) is in the range of 32-36% by
weight.
With regard to the homogenizing in step (vi) too, according to the present
invention, there is no
particular restriction whatsoever, and so it is possible to select any
conceivable procedure in
order to obtain a homogeneous mixture of the mixture prepared in step (v), for
which purpose it
is possible to use, for example, one or more processes selected from the group
consisting of
stirring, kneading, agitating, vibration, or a combination of two or more
thereof. According to the
present invention, the mixture prepared in step (v) is preferably homogenized
by stirring and/or
by vibration in step (vi), the homogenization in step (vi) further preferably
being effected by
vibration, preferably by means of ultrasound, for example by use of an
ultrasound bath into
which the mixture to be homogenized is introduced.
Thus, according to the present invention, preference is given to embodiments
of the process
for preparing a catalyst according to the present invention, and especially a
catalyst according
to one of the particular or preferred embodiments thereof, in which the
homogenizing in (vi) is
effected by stirring, kneading, agitating, vibration or combinations of two or
more thereof,
preferably by stirring and/or vibration, further preferably by vibration, and
further preferably by
means of ultrasound.
With regard to the components which may be present in the mixture prepared in
(v) and
homogenized in (vi), there is no restriction whatsoever in principle, provided
that a coated
support substrate is obtained in (vi). Thus, in particular embodiments, the
mixture prepared in
(v) and/or homogenized in (vi) may consist of the one or more impregnated and
optionally dried
and/or calcined zeolites of the MFI, MEL and/or MVVW structure type and one or
more solvents.
In further embodiments of the inventive catalyst, the mixture prepared in (v)
and/or
CA 02877796 2014-12-23
19
homogenized in (vi) comprises one or more further components to the zeolites
and the solvent.
With regard to the additional components which may be present in the mixture
prepared in (v)
and/or homogenized in (vi), there are no restrictions whatsoever in principle,
and so the mixture
in (v) and/or (vi) may comprise, for example, further catalytic components,
cocatalysts, fillers,
assistants, support substances, binders and combinations of two or more
thereof. In particularly
preferred embodiments, the mixture in (v) and/or in (vi) comprises a binder,
in which case the
binder may comprise one or more substances. In principle, the binder can be
added to the
mixture in (v), to the mixture in (vi), or both to the mixture in (v) and to
the mixture in (vi), with
addition in preferred embodiments of the binder to the mixture in (vi).
In the preferred embodiments in which the binder is added in (vi), this can in
principle be added
either before the homogenization of the mixture or at any time during the
homogenization,
provided that a homogenized mixture is obtained in (vi). In relation to
preferred embodiments in
which the one or more zeolites are brought in step (vi) to a particular D50
and/or Dgo particle
size, particular preference is given to embodiments in which one or more
further components
are added to the zeolites and the solvent, and especially to those in which an
assistant is
added, only after the establishment of the particle size.
With regard to the binder which is optionally added in the process, there are
no restrictions, and
so it is possible in principle to use any substance suitable for this purpose
and any suitable
mixture, provided that it leads to the desired increase in the coherence of
the layer in the coated
support substrate. Thus according to the present invention, for example, SiO2,
Al2O3, TiO2, ZrO2,
MgO, clay minerals and mixtures of two or more thereof, and the respective
precursor
compounds thereof and mixtures of two or more thereof, and also mixtures of
two or more of the
former with two or more of the precursor compounds thereof can be used as
binder in the
inventive process.
A1203 binders and precursor compounds thereof which may be used are, for
example, clay
minerals and naturally occurring or synthetic aluminas such as alpha-, beta-,
gamma-, delta-,
eta-, kappa-, chi- or theta-alumina, and the inorganic and/or organometallic
precursor
compounds thereof, such as gibbsite, bayerite, boehmite, pseudoboehmite, or
trialkoxyaluminates such as aluminum triisopropoxide.
Further binders which can be used in the process are montmorillonite, kaolin,
bentonite,
halloysite, dickite or nacrite.
CA 02877796 2014-12-23
Preferred binders comprise SiO2 and/or one or more of the precursor compounds
thereof, more
preferably SiO2, preference being given to using colloidal SiO2. In
embodiments which are
further preferred, colloidal SiO2 is added as a binder in (v) and/or (vi) and
preferably in (vi).
With regard to the concentration of the binder in the homogenized mixture
obtained in (vi), there
are no restrictions, and so it is possible in principle to use any suitable
amount of binder,
provided that the resulting catalyst can be used for the conversion of at
least one oxygenate to
at least one olefin. Thus, the binder can be obtained, for example, in an
amount of 0.1 to 50%
by weight in (v) and/or (vi) and preferably in (vi), based on the total solids
content of the
homogenized mixture which is obtained in (vi). In further preferred
embodiments, from 0.5 to
35% by weight of binder is added in (v) and/or (vi) and preferably in (vi),
based on the total
solids content of the homogenized mixture obtained in (vi), further preferably
from 1 to 30% by
weight, further preferably from 5 to 25% by weight, further preferably from 7
to 20% by weight,
further preferably from 9 to 17% by weight, further preferably from 10 to 15%
by weight, and still
further preferably from 11 to 13% by weight.
With regard to the coating of the support substrate in step (vii) of the
process according to the
invention, there is in principle no restriction whatsoever with respect to the
performance thereof,
provided that a corresponding layer is formed at least partially on the
support substrate. Thus,
any suitable form of coating or of layer formation can be employed in the
process according to
the invention for preparing the inventive catalyst, the coating in step (vii)
preferably being
effected by spray coating and/or wash coating. In particularly preferred
embodiments of the
process according to the invention, the coating in step (vii) is effected by
wash coating, the
wash coating preferably being effected by dip coating. Such a preferred dip
coating operation is
effected, for example, by dipping the support substrate once or more than once
into the mixture
prepared in step (v) and homogenized in step (vi), and, according to the
present invention, the
dip coating is preferably followed by a treatment to remove excess mixture
from the support
substrate. In preferred embodiments of dip coating, in which the substrate is
dipped repeatedly
into the mixture prepared in step (v) and homogenized in step (vi), the
further preferred
treatment for removal of excess mixture can in principle be effected after the
repeated dipping
and/or between two or more dipping steps, each dipping step preferably being
followed by
removal of excess mixture by a suitable treatment of the coated support
substrate. More
preferably, however, according to the present invention, one dipping step into
the mixture
prepared in step (v) and homogenized in step (vi) is performed, followed by a
corresponding
treatment for removal of excess mixture. With regard to the particularly
preferred removal of
excess mixture according to the particular embodiments of the present process,
in which dip
coating is performed in step (vii), there is in principle no restriction
whatsoever with respect to
the way in which excess mixture is removed. Thus, a removal can be achieved,
for example, by
CA 02877796 2014-12-23
21
suitable hanging of the coated support substrate and/or leaving it to stand,
and/or directly or
indirectly by mechanical or other action, for example by mechanical stripping
and/or by removal
with a suitable gas blower and/or by suitable application of centripetal
forces, for example by
means of centrifugal forces directed in a suitable manner. According to the
present invention,
however, particular preference is given to removing excess mixture by means of
a gas blower,
more preferably with the aid of compressed air by suitable extractive blowing
of the excess
mixture.
Thus, according to the present invention, preference is given to embodiments
of the
process for preparing a catalyst according to the present invention, and
especially a catalyst
according to one of the particular or preferred embodiments thereof, in which
the coating in (vii)
is effected by spray coating and/or wash coating, preferably by wash coating,
the wash coating
preferably being effected by dip coating, which is preferably followed by a
treatment for removal
of excess mixture, the removal of excess mixture preferably being effected at
least partly with
compressed air.
In the process according to the invention, according to the present invention,
it is possible in
principle to provide the support substrate with a plurality of layers of the
same and/or different
composition, especially with respect to the one or more zeolites of the MFI,
MEL and/or MWW
structure type. Thus, preference is given to embodiments of the process
according to the
invention for preparing a catalyst according to the present invention in which
step (vii) is
repeated once or more than once, step (viii) and/or step (ix) and preferably
both step (viii) and
step (ix) preferably being executed between the repetitions. In such preferred
embodiments of
the process according to the invention in which two or more layers of
different composition,
especially with respect to the one or more zeolites, are applied to the
support substrate, steps
(v) and (vi) are also repeated correspondingly in the case of preparation of
the different
compositions of the mixture in step (v), and this may relate not just to the
chemical composition
but also to the further properties of the mixture, for example the average
particle size and/or the
optional drying and/or the optional calcining of the one or more zeolites of
the MFI, MEL and/or
MWW structure type. If the differences in the mixtures prepared in step (v)
for production of the
different layers on the support substrate in these preferred embodiments also
relate to the
impregnation of the one or more zeolites of the MFI, MEL and/or MWW structure
type in step (ii)
of the process according to the invention and/or to optional drying and/or to
optional calcining,
and also to the manner of impregnation in step (ii) and/or of drying in step
(iii) and/or of calcining
in step (iv), steps (ii) and optionally (iii) and/or (iv) are also
correspondingly repeated in these
embodiments. In particularly preferred embodiments of the process according to
the invention,
steps (vii) and (viii) and/or (ix), preferably steps (vii)-(ix), are repeated
once or more than once,
CA 02877796 2014-12-23
22
in order to achieve multiple coating of the support substrate with a mixture
prepared in step (v)
and homogenized in step (vi).
With regard to the number of repetitions which are performed in the preferred
embodiments of
the process according to the invention for preparing a catalyst according to
the present
invention, there is no restriction in principle, and the steps in the
repetitions of the particular and
preferred embodiments of the process according to the invention are preferably
repeated once
to five times, further preferably once to four times, further preferably once
to three times and
further preferably once or twice.
Thus, according to the present invention, preference is given to embodiments
of the
process for preparing a catalyst according to the present invention, and
especially a catalyst
according to one of the particular or preferred embodiments thereof, in which
step (vii) is
repeated once or more than once, preferably steps (vii) and (viii), further
preferably steps (vii) to
(ix), and steps are preferably repeated once to five times, further preferably
once to four times,
further preferably once to three times, further preferably once or twice, and
more preferably
twice.
With regard to the temperature at which the coated support substrate obtained
in (vii) is dried
(viii), and to the duration of drying, there is no restriction in principle.
For example, the optional
drying in (viii) can be effected at a temperature in the range from 50 to 220
C, the drying
preferably being effected at a temperature in the range from 80 to 200 C,
further preferably in
the range from 100 to 180 C, further preferably in the range from 110 to 170
C, further
preferably in the range from 120 to 160 C, further preferably in the range
from 130 to 150 C,
and further preferably in the range from 135 to 145 C. With regard to the
duration of drying,
there is likewise no restriction whatsoever, and so it can be performed, for
example, for a period
of 0.1 to 5 h, the drying in step (viii) preferably being performed for a
period of 0.2 to 2 h, further
preferably of 0.3 to 1.5 h, further preferably of 0.4 to 1.2 h, further
preferably of 0.5 to 1 h,
further preferably of 0.6 to 0.9 h, and further preferably of 0.7 to 0.8 h.
With regard to the temperature at which the coated support substrate obtained
in (vii) or (viii) is
calcined in (ix), and to the duration of calcination, there is in principle no
restriction whatsoever.
For example, the optional calcination in (ix) can be effected at a temperature
in the range from
250 to 1100 C, the calcination preferably being effected at a temperature in
the range from 350
to 900 C, further preferably in the range from 400 to 800 C, further
preferably in the range from
450 to 750 C, further preferably in the range from 500 to 700 C, further
preferably in the range
from 550 to 650 C, and further preferably in the range from 580 to 600 C. With
regard to the
duration of calcination, there is likewise no restriction whatsoever, and so
this can be performed,
for example, for a duration of 0.5 to 20 h, the calcination in step (ix)
preferably being performed
CA 02877796 2014-12-23
23
for a period of 0.75 to 15 h, further preferably of 1 to 10 h, further
preferably of 1.5 to 5 h, further
preferably of 2 to 4 h, further preferably of 2.5 to 3.5 h, and further
preferably of 2.8 to 3.2 h.
In particularly preferred embodiments of the process according to the
invention, the coated
substrate obtained in (vii) is both dried and then calcined.
As well as a catalyst for the conversion of oxygenates to olefins according to
the present
invention as described in the present application, and especially according to
the particular and
preferred embodiments thereof, the present invention likewise relates to those
catalysts for the
conversion of oxygenates to olefins which are obtainable by the preparation
process according
to the invention, i.e. including catalysts per se which can be obtained by the
preparation process
according to the invention, without necessarily having to be prepared by this
process. More
particularly, the present invention thus relates to catalysts for the
conversion of oxygenates to
olefins which can be prepared by the process according to the invention,
especially according to
the particular and preferred embodiments thereof described in the present
application, but can
be or have been prepared by another process suitable for this purpose.
Thus, according to the present invention, preference is given to embodiments
of the catalyst
for the conversion of oxygenates to olefins in which the catalyst, and
especially the catalyst
according to one of the particular or preferred embodiments of the present
invention, is
obtainable by the process according to the invention for preparing a catalyst,
preferably by
one of the particular or preferred embodiments of the process according to the
invention.
As well as a catalyst for the conversion of oxygenates to olefins and a
process for preparing
such a catalyst, the present invention also relates to a process for
converting oxygenates to
olefins. More particularly, the present invention relates to such a process
comprising:
(1) providing a gas stream comprising one or more oxygenates;
(2) contacting the gas stream with a catalyst according to the present
invention.
With regard to the catalyst which can be used in the process according to the
invention for
converting oxygenates to olefins, there is in principle no restriction
whatsoever, provided that it
is a catalyst according to the present invention as obtainable, for example,
also by the process
according to the invention, and provided that this catalyst is suitable for
the conversion of at
least one oxygenate to at least one olefin. This is especially true of the
embodiments of the
inventive catalyst according to the particular and preferred embodiments of
the present
invention.
CA 02877796 2014-12-23
24
The same applies correspondingly to the one or more oxygenate(s) present in
the gas stream
according to (1), and so there is no restriction here whatsoever in principle
in the process
according to the invention, provided that the one or more oxygenates present
in the gas stream
according to (1) can be converted by one of the catalysts according to the
present invention and
especially according to the particular and preferred embodiments thereof to at
least one olefin
when contacted according to (2). According to the present invention, however,
it is preferable
that the one or more oxygenates present in the gas stream according to (1) is
selected from the
group consisting of aliphatic alcohols, ethers, carbonyl compounds and
mixtures of two or more
thereof. Further preferably, the one or more oxygenates are selected from the
group consisting
of (Cl-C6)-alcohols, di(Ci-C3)alkyl ethers, (Gi-C6)-aldehydes, (G2-C6)-ketones
and mixtures of
two or more thereof, further preferably consisting of (Gi-C4)-alcohols, di(Ci-
C2)alkyl ethers, (GI-
GO-aldehydes, (G2-C4)-ketones and mixtures of two or more thereof. In yet
further preferred
embodiments of the present invention, the gas stream according to (1)
comprises one or more
oxygenates selected from the group consisting of methanol, ethanol, n-
propanol, isopropanol,
butanol, dimethyl ether, diethyl ether, ethyl methyl ether, diisopropyl ether,
di-n-propyl ether,
formaldehyde, dimethyl ketone and mixtures of two or more thereof, the one or
more
oxygenates further preferably being selected from the group consisting of
methanol, ethanol,
dimethyl ether, diethyl ether, ethyl methyl ether and mixtures of two or more
thereof. In
particularly preferred embodiments of the process according to the invention
for conversion of
oxygenates to olefins, the gas stream according to (1) comprises methanol
and/or dimethyl
ether as the one or more oxygenates, and dimethyl ether is more preferably the
oxygenate
present in the gas stream according to (1).
Thus, according to the present invention, preference is given to embodiments
of the process
for converting oxygenates to olefins in which the gas stream according to (1)
comprises one or
more oxygenates selected from the group consisting of aliphatic alcohols,
ethers, carbonyl
compounds and mixtures of two or more thereof, preferably consisting of (C1-
C6) alcohols,
di(Ci-C3)alkyl ethers, (C1-C6) aldehydes, (G2-G6) ketones and mixtures of two
or more thereof,
further preferably consisting of (Ci-C4) alcohols, di(Ci-G2)alkyl ethers, (C1-
C4) aldehydes, (C2-
G4) ketones and mixtures of two or more thereof, further preferably from the
group consisting of
methanol, ethanol, n-propanol, isopropanol, butanol, dimethyl ether, diethyl
ether, ethyl methyl
ether, diisopropyl ether, di-n-propyl ether, formaldehyde, dimethyl ketone and
mixtures of two or
more thereof, further preferably from the group consisting of methanol,
ethanol, dimethyl ether,
diethyl ether, ethyl methyl ether and mixtures of two or more thereof, the gas
stream further
preferably comprising methanol and/or dimethyl ether, and more preferably
dimethyl ether.
On the other hand, with regard to the content of oxygenates in the gas stream
according to (1)
in the process according to the invention for converting oxygenates to
olefins, there is no
CA 02877796 2014-12-23
restriction according to the present invention here either, provided that,
when the gas stream is
contacted in (2) with a catalyst according to the present invention, at least
one oxygenate can
be converted to at least one olefin. In preferred embodiments, the content of
oxygenates in the
gas stream according to (1) is in the range from 30 to 100% by volume based on
the total
volume, the content especially being based on a gas stream at a temperature in
the range from
200 to 700 C and at a pressure of 101.3 kPa, preferably at a temperature in
the range from 250
to 650 C, further preferably from of 300 to 600 C, further preferably from 350
to 560 C, further
preferably from 400 to 540 C, further preferably from 430 to 520 C, and
further preferably in the
range from 450 to 500 C and at a pressure of 101.3 kPa. According to the
present invention, it
is further preferred that the content of oxygenates in the gas stream
according to (1) is in the
range from 30 to 99% by volume, further preferably from 30 to 95% by volume,
further
preferably from 30 to 90% by volume, further preferably from 30 to 80% by
volume, further
preferably from 30 to 70% by volume, further preferably from 30 to 60% by
volume and further
preferably from 30 to 50% by volume. In particularly preferred embodiments of
the process
according to the invention for converting oxygenates to olefins, the content
of oxygenates in the
gas stream according to (1) is in the range from 30 to 45% by volume.
Thus, according to the present invention, preference is given to embodiments
of the
process for converting oxygenates to olefins in which the content of
oxygenates in the gas
stream according to (1) is in the range from 30 to 100% by volume based on the
total volume,
preferably from 30 to 99% by volume, further preferably from 30 to 95% by
volume, further
preferably from 30 to 90% by volume, further preferably from 30 to 80% by
volume, further
preferably from 30 to 70% by volume, further preferably from 30 to 60% by
volume, further
preferably from 30 to 50% by volume, and further preferably from 30 to 45% by
volume.
With regard to the other components in the gas stream according to (1) in the
process according
to the invention, there is in principle no restriction whatsoever, provided
that the gas stream is
suitable overall for conversion of at least one of the oxygenates to at least
one olefin in step (2)
when contacted with a catalyst according to the present invention. In
addition, for example, as
well as the one or more oxygenates in the gas stream according to (1), one or
more inert gases
may also be present therein, for example one or more noble gases, nitrogen,
water and
mixtures of two or more thereof. In particular embodiments of the present
invention, the gas
stream according to (1) of the process according to the invention, as well as
the one or more
oxygenates, comprises water.
With regard to those preferred embodiments in which, as well as the one or
more oxygenates,
water is present in the gas stream according to (1), there is no restriction
in principle with
respect to the water content which may be present therein, provided that the
conversion of at
CA 02877796 2014-12-23
26
least one oxygenate in the gas stream to at least one olefin in step (2) of
the contacting of the
gas stream can be effected with a catalyst according to the present invention.
In these preferred
embodiments, however, it is preferable that the water content in the gas
stream is in the range
from 5 to 60% by volume based on the total volume, the water content more
preferably being in
the range from 10 to 55% by volume, further preferably from 20 to 50% by
volume and further
preferably from 30 to 45% by volume.
Thus, according to the present invention, preference is given to embodiments
of the
process for converting oxygenates to olefins in which water is present in the
gas stream
according to (1), preferably in the range from 5 to 60% by volume based on the
total volume,
preferably from 10 to 55% by volume, further preferably from 20 to 50% by
volume, and further
preferably from 30 to 45% by volume.
In particularly preferred embodiments of the process according to the
invention for converting
oxygenates to olefins, the gas stream provided in (1) originates from a
preliminary reaction,
preferably from the conversion of one or more alcohols to one or more ethers,
especially from
the conversion of one or more alcohols selected from the group consisting of
methanol, ethanol,
n-propanol, isopropanol and mixtures of two or more thereof, further
preferably from the group
consisting of methanol, ethanol, n-propanol and mixtures of two or more
thereof, the gas stream
provided in (1) more preferably originating from a preliminary reaction of
methanol and/or
ethanol and methanol further preferably being at least partly converted to one
or more di(C1-
C2)alkyl ethers, preferably to one or more di(Ci-C2)alkyl ethers selected from
the group
consisting of dimethyl ether, diethyl ether, ethyl methyl ether and mixtures
of two or more
thereof. For instance, the gas stream provided in (1), in a particularly
preferred embodiment,
originates from a preliminary reaction of conversion of methanol to dimethyl
ether.
In the particularly preferred embodiments of the process according to the
invention in which the
gas stream provided in (1) originates from a preliminary reaction of one or
more alcohols, there
is no particular restriction whatsoever in principle with respect to the
reaction and hence the
reaction product of the conversion of one or more alcohols, provided that this
leads to a gas
stream comprising one or more oxygenates which, when contacted in (2) with a
catalyst
according to the present invention, enables the conversion of at least one of
the oxygenates to
at least one olefin. In these particular embodiments, it is further preferable
that the preliminary
reaction leads to conversion of at least one alcohol to at least one ether and
especially to at
least one dialkyl ether, the preliminary reaction more preferably being a
dehydration in which
water is obtained as a coproduct to one or more dialkyl ethers. In the
particular and preferred
embodiments of the present invention in which the gas stream provided in (1)
originates from a
preliminary reaction, it is particularly preferred in the process according to
the invention that
CA 02877796 2014-12-23
27
such a gas stream originating from a preliminary reaction is supplied directly
and without workup
to the process according to the invention in step (1).
With respect to the manner of contacting the gas stream with a catalyst
according to the present
invention in step (2) of the process according to the invention for converting
oxygenates to
olefins, there is in principle no restriction whatsoever, provided that the
conversion of at least
one oxygenate to at least one olefin can be implemented. This applies, for
example, to the
temperature at which the contacting (2) takes place. Thus, for example, the
contacting in step
(2) of the process according to the invention can take place at a temperature
in the range from
200 to 700 C, preference being given to selecting temperatures in the range
from 250 to 650 C,
further preferably from 300 to 600 C, further preferably from 350 to 560 C,
further preferably
from 400 to 540 C and further preferably from 430 to 520 C. In particularly
preferred
embodiments of the present invention, the contacting according to (2) of the
process according
to the invention is performed at a temperature in the range from 450 to 500 C.
Thus, according to the present invention, preference is given to embodiments
of the
process for converting oxygenates to olefins in which the contacting according
to (2) is effected
at a temperature in the range from 200 to 700 C, preferably from 250 to 650 C,
further
preferably from 300 to 600 C, further preferably from 350 to 560 C, further
preferably from 400
to 540 C, further preferably from 430 to 520 C, and further preferably from
450 to 500 C.
The same applies correspondingly to the pressure at which the gas stream is
contacted in step
(2) of the process according to the invention with the catalyst according to
the present invention,
Thus, the contacting can in principle take place at any desired pressure,
provided that this
allows the conversion of at least one oxygenate to at least one olefin by
virtue of the contacting
of the gas stream with the catalyst. Thus, the pressure, for example in the
contacting in step (2),
may be in the range from 0.1 to 10 bar, the pressure according to the present
application
indicating the absolute pressure, such that a pressure of 1 bar in the
contacting accordingly
corresponds to the standard pressure of 1.03 kPa. According to the present
invention, the
contacting in step (2) takes place preferably at a pressure from 0.3 to 7 bar,
further preferably
from 0.5 to 5 bar, further preferably from 0.7 to 3 bar, further preferably
from 0.8 to 2.5 bar and
further preferably from 0.9 to 2.2 bar. In particularly preferred embodiments
of the process
according to the invention for converting oxygenates to olefins, the
contacting in step (2) takes
place at a pressure of 1 to 2 bar.
Thus, according to the present invention, preference is given to embodiments
of the
process for converting oxygenates to olefins in which the contacting according
to (2) is
effected at a pressure in the range from 0.1 to 10 bar, preferably from 0.3 to
7 bar, further
CA 02877796 2014-12-23
28
preferably from 0.5 to 5 bar, further preferably from 0.7 to 3 bar, further
preferably from 0.8 to
2.5 bar, further preferably from 0.9 to 2.2 bar, and further preferably from 1
to 2 bar.
In addition, there are no particular restrictions with respect to the manner
of performance of the
process according to the invention for converting oxygenates to olefins, and
so it is possible to
use either a continuous or a noncontinuous process, the noncontinuous process
being
performable, for example, in the form of a batch process. According to the
present invention, it
is preferable to conduct the process according to the invention for the
conversion of oxygenates
as a continuous process. Thus, according to the present invention, preference
is given to
embodiments of the process for converting oxygenates to olefins in which the
process is a
continuous process.
With respect to these preferred embodiments of a continuous process, there are
no restrictions
whatsoever with respect to the space velocity selected, provided that the
conversion of an
oxygenate to an olefin can be effected. Thus, it is possible to select, for
example, space
velocities in the contacting in step (2) which are in the range from 0,5 to 50
h-1, preference being
given to selecting space velocities (WHSV = weight hourly space velocity is
calculated as the
ratio of oxygenate reactant stream in kg/h to the amount of zeolite in the
reactor in kg) from 1 to
30 h-1, further preferably from 3 to 25 h-1, further preferably from 5 to 20 h-
1, further preferably
from 7 to 15 h-1 and further preferably from 8 to 12 h-1. In particularly
preferred embodiments of
the process according to the invention for converting oxygenates, space
velocities for the
contacting of the gas stream in step (2) in the range from 9 to 11 h-1 are
selected. In alternative
embodiments of the continuous process, and especially in preferred embodiments
in which the
layer applied to the substrate in the catalyst further comprises a binder,
space velocities in the
course of contacting in step (2) in the range from 0.1 to 20 h-1 may be
selected, preference
being given to selecting space velocities of 0.5 to 15 h-1, further preferably
of 1 to 10 h-1, further
preferably of 1.5 to 8 h-1, further preferably of 2 to 7 h-1, further
preferably of 2.5 to 6 h-1, further
preferably of 3 to 5 h-1, and further preferably of 3.5 to 4.5 h-1.
Thus, according to the present invention, preference is given to embodiments
of the
process for converting oxygenates to olefins in which the space velocity in
the course of
contacting according to (2) is in the range from 0.5 to 50 h-1, preferably
from 1 to 30 h-1, further
preferably from 3 to 25 h-1, further preferably from 5 to 20 h-1, further
preferably from 7 to 15 h-1,
further preferably from 8 to 12 h-1, and further preferably from 9 to 11 h-1.
Accordingly, preference
is likewise given in accordance with the present invention to embodiments of
the process for
converting oxygenates to olefins in which the space velocity in the course of
contacting in step (2)
is in the range from 0.1 to 20 h-1, preferably from 0.5 to 15 h-1, further
preferably from 1 to 10 h-1,
CA 02877796 2014-12-23
29
further preferably from 1.5 to 8 h-1, further preferably from 2 to 7 h-1,
further preferably from 2.5 to
6 h-1, further preferably from 3 to 5 h-1, and further preferably from 3.5 to
4.5 h-1.
As described above and shown in the examples of the present application, it is
possible to
achieve particularly long service lives with the inventive catalyst in a
process for converting
oxygenates as described in the present application, especially with respect to
the particular and
preferred embodiments of the process according to the invention. It has thus
been found that,
surprisingly, the use of a catalyst according to the present invention can
considerably increase
the service life of the catalyst before the process has to be interrupted for
regeneration of the
catalyst, at least with respect to the use of this catalyst batch compared to
the use of catalysts
according to the prior art. It is thus particularly preferable according to
the present invention to
select long service lives for the performance of the process for converting
oxygenates to olefins
at one of the particular or preferred space velocities, as described in the
present application.
Thus, preference is given to service lives in the range from 15 to 400 h,
further preferably in the
range from 20 to 300 h, further preferably from 60 to 250 h, further
preferably from 90 to 220 h,
further preferably from 110 to 200 h, further preferably from 130 to 180 h,
further preferably from
150 to 170 h and further preferably from 155 to 165 h. More particularly,
based on the particular
and preferred space velocities at which the process according to the invention
is performed,
preference is thus given, for example, to service lives of 15 to 400 h at a
space velocity in the
range from 0.5 to 50 h-1. Further preference is given to a service life of 20
to 300 h at a space
velocity of 1 to 30 h-1, further preference to a service life of 60 to 250 h
at a space velocity of 1
to 30 h-1, further preference to a service life of 90 to 220 h at a space
velocity of 3 to 25 h-1,
further preference to a service life of 110 to 200 h at a space velocity in
the range from 5 to
20 h-1, further preference to a service life of 130 to 180 h at a space
velocity in the range from 7
to 5 h-1 and further preferably of 150 to 170 h at a space velocity of 8 to 12
h-1. In a particularly
preferred embodiment of the process according to the invention, a service life
of the catalyst,
during which the continuous process is performed without interruption, in the
range from 155 to
165 h at a space velocity of 9 to 11 h-1 is selected.
In alternative embodiments of the present invention, and especially in
preferred embodiments in
which the layer applied to the substrate in the catalyst further comprises a
binder, preference is
given to service lives in the range from 5 to 800 h, further preferably in the
range from 10 to
600 h, further preferably in the range from 30 to 550 h, further preferably in
the range from 50 to
500 h, further preferably in the range from 70 to 450 h, further preferably in
the range from 80 to
420 h, further preferably in the range from 90 to 400 h, and further
preferably in the range from
100 to 380 h. More particularly, based on the particular and preferred space
velocities at which
the process according to the invention is performed in alternative
embodiments, and especially
CA 02877796 2014-12-23
in preferred embodiments in which the layer applied to the substrate in the
catalyst further
comprises a binder, preference is thus given, for example, to service lives of
5 to 800 h at a
space velocity in the range from 0.1 to 20 h-1. Further preference is given to
a service life of 10
to 600 h at a space velocity of 0.5 to 15 h-1, further preference to a service
life of 30 to 550 h at
a space velocity of 1 to 10 h-1, further preference to a service life of 50 to
500 h at a space
velocity of 1.5 to 8 h-1, further preference to a service life of 70 to 450 h
at a space velocity of 2
to 7 h-1, further preference to a service life of 80 to 420 h at a space
velocity of 2.5 to 6 h-1,
further preference to a service life of 90 to 400 h at a space velocity of 3
to 5 h-1, and further
preference to a service life of 100 to 380 h at a space velocity of 3.5 to 4.5
h-1.
According to the present invention, the particular and preferred embodiments
with respect to the
service life selected and especially the service lives selected in combination
with particular
space velocities preferably relate to a minimum conversion of the one or more
oxygenates
present in the gas stream according to (1) of the process according to the
invention, sustained
conversion below this value leading to subsequent performance of the
regeneration of the
catalyst. According to the present invention, there is no particular
restriction with respect to the
minimum conversion selected, this preferably allowing full conversion of the
one or more
oxygenates present in the gas stream according to (1) of the process according
to the invention
during the service life of the catalyst. Thus, in preferred embodiments of the
present invention, a
minimum conversion of 60% of the one or more oxygenates present in the gas
stream
according to (1) of the process according to the invention is selected,
sustained conversion
below this value leading to performance of the regeneration of the catalyst,
preferably a
minimum conversion of 70% or more, further preferably of 80% or more, further
preferably of
85% or more, further preferably of 90% or more, further preferably of 95% or
more, further
preferably of 97% or more, further preferably of 98% or more, and further
preferably of 99% or
more of the one or more oxygenates present in the gas stream according to (1)
of the process
according to the invention.
Thus, according to the present invention, further preference is given to
embodiments of the
process for converting oxygenates to olefins in which the service life of the
coated support
substrate as a catalyst, during which the continuous process is performed
without interruption, is
in the range from 15 to 400 h, preferably from 20 to 300 h, further preferably
from 60 to 250 h,
further preferably from 90 to 220 h, further preferably from 110 to 200 h,
further preferably from
130 to 180 h, further preferably from 150 to 170 h, and still further
preferably from 155 to 165 h.
The present invention further also relates to the use of the inventive
catalyst as described
above, and especially to the use of the inventive catalyst according to the
particular and
preferred embodiments as described in the present application. According to
the present
CA 02877796 2014-12-23
31
invention, there is no restriction whatsoever in principle with respect to the
use of the inventive
catalyst, and so it can be used either for the conversion of oxygenates to
olefins or in any
conceivable catalytic process in which the catalyst exhibits a corresponding
catalytic action with
respect to a chemical conversion. According to the present invention, however,
the inventive
catalyst is preferably used in a methanol-to-olefin process (MTO process), and
further
preferably in a methanol-to-gasoline process (MTG process), in a methanol-to-
hydrocarbon
process, in a methanol-to-propylene process (MTP process), in a methanol-to-
propylene/butylene process (MT3/4 process) and for alkylation of aromatics, or
in a fluid
catalytic cracking process (FCC process). According to the present invention,
however, the
inventive catalyst is preferably used in a methanol-to-olefin process (MTO
process), more
preferably in a methanol-to-propylene/butylene process (MT3/4 process),
especially in a
process for converting oxygenates to olefins in one of the particular or
preferred processes for
converting oxygenates to olefins according to the present invention.
EXAMPLES
Comparative example 1: Preparation of an extrudate comprising H-ZSM-5
380 g of H-ZSM-5 (ZEO-cat PZ2-100 H from Zeochem) with Si/AI = 50 were mixed
with 329 g of
pseudoboehmite (Pural SB; Sasol), 10 g of formic acid in 50 ml of water were
added, and the
mixture was processed with 300 ml of water in a kneader to give a homogeneous
material. The
starting weights were selected such that the zeolite/binder ratio in the
calcined extrudates
corresponds to 60:40. This kneaded material was pushed with the aid of an
extrudate press at
approx. 100 bar through a 2.5 mm die. The extrudates were subsequently dried
in a drying
cabinet at 120 C for 16 h and (after heating time 4 h) calcined in a muffle
furnace at 500 C for
4 h. Thereafter, the extrudates were processed in a sieving machine with 2
steel balls (diameter
approx. 2 cm, 258 g/ball) to give 1.6-2.0 mm spell.
Comparative example 2: Preparation of a support coated with H-ZSM-5 (loading:
71 g/l)
An aqueous suspension having a solids concentration of 40% by weight of H-ZSM-
5 zeolite
(ZEO-cat PZ2-100 H from Zeochem) with Si/AI = 50 was prepared and homogenized
in an
ultrasound bath. Cylindrical honeycomb pieces of cordierite (900 cpsi,
diameter 0.9 cm,
length = 11 cm) were dipped into this suspension and then blown dry with
compressed air. The
coated supports were then dried at 110 C for 1 h and subsequently calcined at
550 C for 3 h.
The coating step was repeated until a loading of 0.5 g of zeolite per
honeycomb piece
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(0.071 g/cm3) was attained, the amount of suspension applied being reported in
grams of dry
substance per liter of total honeycomb volume.
Example 1: Preparation of a support coated with Mg-ZSM-5 (loading: 71 g/1)
H-ZSM-5 (ZEO-cat PZ2-100 H from Zeochem) with Si/AI = 50 powder was spray
impregnated
with an amount of magnesium nitrate solution corresponding to 90% of its water
uptake
capacity. The amount of Mg weighed in was such that the powder after the
calcination
comprises 4% by weight of Mg. For impregnation, 58.7 g of zeolite powder were
introduced into
a round-bottom flask and placed in a rotary evaporator. 43.9 g of magnesium
nitrate were
dissolved in water while heating, and made up to 54 ml of total liquid with
dist. water. The
resulting magnesium nitrate solution was introduced into a dropping funnel,
and sprayed
gradually onto the powder through a glass spray nozzle flooded with 100 l/h of
N2 while rotating.
At regular intervals during this time, the flask was detached and shaken by
hand, in order to
achieve homogeneous distribution. On completion of addition of the magnesium
nitrate solution,
the powder was rotated further for 10 min. Subsequently, the powder was dried
at 120 C in a
quartz rotary sphere flask for 16 h, then calcined at 500 C under air (20 1/h)
for 5 h, and the
calcined powder was subsequently ground to a small size with the aid of an
analytical mill and
sieved through a sieve having a mesh size of 1 mm.
The BET surface area of the resulting magnesium-impregnated zeolite was 303
m2/g.
Elemental analysis:
Mg: 4g/100g
The Mg-ZSM-5 powder prepared by spray impregnation was applied to honeycomb
pieces
according to comparative example 2, with a solids concentration of Mg-ZSM-5 in
the aqueous
suspension used for this purpose of 20% by weight. The coating step was
repeated according to
comparative example 2 until a loading of 0.5 g of Mg-ZSM-5 per honeycomb piece
(0.071 g/cm3) was attained.
Example 2: Preparation of a support coated with Mg-ZSM-5 (loading: -85 g/I)
Distilled water was initially charged in a vessel with a propeller stirrer.
While continuously stirring
and adjusting the speed, Mg-ZSM-5 powder which was prepared according to
example 1 was
added gradually until a solids content of 33% by weight had been attained.
This was followed by
grinding of the Mg-ZSM-5 starting suspension in a stirrer ball mill to a
particle size D90 of 10 pm.
During the grinding, the temperature did not exceed 30 C. After the grinding,
Ludox AS-40 was
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added as a binder. The solids content of the binder was 12% by weight overall,
based on the
total solids content of the final suspension.
To prepare the support substrate, the suspension was applied to a honeycomb
(cordierite
honeycomb having a cell density of 400 cpsi (62 cells/cm2) and a wall
thickness of 6-7 mil
(152.4 pm-177.8 pm)). For this purpose, the suspension was diluted to a solids
content of 28%.
The catalyst was immersed into the suspension over the full height, such that
all cells were
completely filled. After a wait time of 10 seconds, the substrate was
extracted from the
suspension, turned over and freed of excess suspension with compressed air
from the inlet to
the outlet side.
Subsequently, the catalyst was dried in a dryer by means of hot air (140 C),
alternately from
both sides with a respective cycle time of 10 seconds, for a total of 45
minutes. Thereafter, the
catalyst was calcined in a flow calciner at a maximum temperature of 590 C,
and the catalyst
during the operation passed through three heating zones, one constant
temperature zone and
one cooling zone within three hours.
The loading of the carrier substrate was calculated by means of a mass balance
to be
0.085 g/cm3.
Example 3: Preparation of a support coated with Mg-ZSM-5 (loading: -150 g/I)
The preparation method according to example 2 was repeated, except the support
substrate
was coated twice. For this purpose, the suspension was first diluted to a
solids content of 26%
with distilled water, and the catalyst was coated therewith according to
example 2, and the layer
was then thermally fixed. The suspension was then diluted further to a solids
content of 25%,
and the operation of coating and thermal fixing according to example 2 was
repeated with this
suspension, achieving a loading of the support substrate of 0.15 g/0m3.
Example 4: Preparation of a support coated with Mg-ZSM-5 (loading: -190 g/1)
The preparation method according to example 2 was repeated, except the support
substrate
was coated repeatedly as in example 3. For this purpose, the suspension was
first diluted to a
solids content of 28% with distilled water, and the catalyst was coated
therewith according to
example 2, and the layer was then thermally fixed. The suspension was then
diluted further to a
solids content of 25%, and the operation of coating and thermal fixing
according to example 2
was repeated with this suspension, achieving a loading of the support
substrate of 0.19 g/cm3.
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Example 5: Comparative tests in the methanol-to-propylene/butylene process
(MT3/4 process)
2 g of the catalyst prepared according to comparative example 1 were mixed
with 24 g of silicon
carbide and installed in a continuous, electrically heated tubular reactor,
such that the bed in the
reactor has a length of 30 cm and a diameter of 12 mm. For the tests using the
catalysts
prepared according to comparative example 2 and according to examples 1 to 4,
two of the
coated honeycomb bodies in each case were installed in the reactor and sealed
at the tube wall
with glass fiber cord.
Upstream of the test reactor, methanol vapor was produced to give a gas stream
comprising
75% by volume of methanol and 25% by volume of N2, which was converted to
dimethyl ether
by means of a preliminary reactor charged with 34 ml of alumina spall at 275 C
and an
(absolute) pressure of 1-2 bar. The stream comprising dimethyl ether was then
passed into the
tubular reactor, and converted therein at a temperature of 450 to 500 C, a
WHSV (= weight
hourly space velocity), according to the specimen, in the range from 3.6 to 10
h-1 based on
methanol and an (absolute) pressure of 1 to 2 bar, and the reaction parameters
were
maintained over the entire run time. Downstream of the tubular reactor, the
gaseous product
mixture was analyzed by on-line chromatography.
The results achieved in the MT3/4 process for the catalysts according to
comparative examples
1 and 2 and according to examples 1 to 4 with respect to the selectivities are
shown in table 1,
these reproducing the average selectivities during the run time of the
catalyst in which the
conversion of methanol was 95% or more.
Table 1: Average selectivities of a cycle (methanol conversion of >95%).
Comparative Comparative Example Example Example Example
example 1 example 2 1 2 3 4
Loading [g/1] 71 71 82 156 192
Service life [h] 33 53 160 99 271 381
WHSV [h-1] 10 7 10 8.4 4.4 3.6
Me0H load per
cycle [kgmeoH = 330 371 1600 832 1192 1372
kgzeolitel
Selectivity [%]:
ethylene 9 8 6 5.3 8.1 10.7
propylene 24 19 32 44.2 39.4 39.8
butylene 15 17 27 27.1 29.2 28.2
C4 paraffins 10 12 4 1.7 2.3 2.2
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C5+ (mixture) ixtu re) 16 18 25 15.3 13.4 10.2
aromatics 19 18 5 4.3 5.2 6.0
Ci-C3 paraffins 7 8 2 2.2 2.4 2.8
As can be inferred from the values in table 1, surprisingly, the specific use
of an alkaline earth
metal-comprising zeolite which has been applied to a support substrate in an
MT3/4 process
leads not only to very high selectivities with respect to propylene and
butylene in the product
stream, but these are also maintained over a surprisingly long period, as can
be seen from the
unexpectedly high service lives of the catalyst for which a conversion of
methanol of more than
95% can be maintained.
As can be seen from the results for comparative examples 1 and 2 and for
example 1 in table 1,
it has been found that an increase in the service life or an unexpected
increase in the Me0H
load per cycle which is achieved by the application of the zeolite to a
substrate can
unexpectedly be increased by several times through the additional use of an
alkaline earth
metal zeolite. All the more surprising, however, is the fact that this
simultaneously brings about
an unexpected and particularly also constant selectivity of the catalyst
according to example 1
extending as far as the C3 and C4 olefins propylene and butylene. Thus, the
present invention
provides a catalyst for the conversion of oxygenates to olefins which, as has
been shown by the
test results in the MT3/4 process according to example 5, has an unexpectedly
high selectivity
with respect to 03 and C4 olefins, which is associated with surprisingly long
service lives,
especially compared to a catalyst which is present in extrudate form (see
comparative example
1) or which has been applied to a support substrate but does not comprise any
alkaline earth
metal (see comparative example 2).
As can be seen from the results for the catalysts from examples 2, 3 and 4,
which comprise a
binder compared to example 1, the considerable improvement in service life was
observed in
spite of the use of a binder. More particularly, a constantly higher loading
of the catalyst in
examples 3 and 4 achieved a further considerable rise in the service life,
even though it was not
quite possible to attain the methanol load per cycle which is observed in
example 1. On the
other hand, however, the use of a binder leads to a catalyst having a much
higher durability
through the better adhesion of the layer.
Very surprisingly, however, it was found that the use of a binder leads to a
further rise in the
selectivity of the catalyst for the 03- and C4-olefins. More particularly, a
considerable jump is
observed in the selectivity for the 03-olefins in example 2 compared to
example 1, which already
shows a considerable rise compared to the selectivities for C3- and 04-olefins
in the comparative
examples. This occurs particularly without trade-offs with regard to the
selectivities for
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Ca-olefins, which corresponds to the results of example 1. In the case of each
increase in the
loading in examples 3 and 4, a likewise very high selectivity for C3-olefins
is observed compared
to example 1, and especially to the comparative examples. Surprisingly,
however, the selectivity
for Ca-olefins increases in examples 3 and 4, the highest selectivity being
observed for example
3.
Thus, the present invention also provides a catalyst for the conversion of
oxygenates to olefins
which, through the use of a binder, not only increases the durability of the
catalyst but also the
service life thereof through the possibility of using higher loadings of the
catalyst on the support
substrate. More particularly, however, it has been found that, surprisingly,
the specific use of a
binder in the inventive catalyst was able to result in to a further
improvement in the selectivity for
Ca-olefins, and more particularly also for C3-olefins. Accordingly, the
present invention provides
a greatly improved catalyst for the conversion of oxygenates to olefins, which
especially has
long services lives combined with simultaneously high selectivities for C3-
and Ca-olefins.
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Prior art documents cited
- Antia et al. in Ind. Eng. Chem. Res. 1995, 34, pages 140-147
- US 4,692,423
- lvanova et al. in J. Phys. Chem. C 2007, 111, pages 4368-4374
- Patcas, F. C. in Journal of Catalysis 2005, 231, pages 194-200
- WO 98/29519 Al
- WO 94/25151 Al
- Hammon et al. in Applied Catalysis 1988, 37, pages 155-174
- Li et al. in Catal. Lett. 2009, 129, pages 408-415
- DD 238733 Al
- McIntosh et al. in Applied Catalysis 1983, 6, p. 307-314
- US 4,049,573
- Goryainova et al. in Petroleum Chemistry 2011, vol. 51, no. 3, p. 169-173
- Ciambelli et at. "Acid-base catalysis in the conversion of methanol to
olefins over Mg-
modified ZSM-5 zeolite", Successful Design of Catalysts, Elsevier Science
Publishers
B.V., Amsterdam, 1988, p. 239-246
- Okado et al. in Applied Catalysis 1988, 41, p. 121-135
