Note: Descriptions are shown in the official language in which they were submitted.
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PF 70061 1
As originally filed
Highly active water gas shift catalyst, preparation process and use thereof
Description
The present invention relates to a highly active water gas shift catalyst and
a process
for producing it, and also a process for converting a gas mixture comprising
at least
carbon monoxide and water into hydrogen and carbon dioxide in a wide
temperature
range using this catalyst.
In a fuel cell, electric energy is obtained by means of chemical reaction.
Most fuel cells
utilize the reaction of a reducing stream with an oxidizing stream, usually
hydrogen and
oxygen. To make a fuel usable in a fuel cell, this has to be converted
beforehand into a
hydrogen-rich stream.
The preliminary processing of fuels is often carried out in three steps:
The fuel is firstly reformed and in this way dissociated into CO and H2. This
is followed
by a water gas shift stage in which the CO formed is reacted with water in a
temperature-dependent equilibrium reaction to give CO2 and H2:
CO + H20 CO2 + H2
This equilibrium lies more to the side of H2 and 002, the lower the
temperature. A CO
fine purification stage usually follows.
High concentrations (greater than 50 ppm) of CO damage the anode of the fuel
cells.
The CO content therefore has to be minimized before the actual cell. This is
carried out
in the water gas shift stage and also in the CO fine purification stage. The
water gas
shift stage usually occurs in two temperature stages. A reaction at
temperatures in the
range from 150 C to 280 C is referred to as a low-temperature shift reaction
(LTS). The
LTS is usually carried out catalytically using Cu/Zn oxide catalysts. In the
range from
280 C to 550 C, the reaction is referred to as a high-temperature shift
reaction (HTS).
This is traditionally carried out over Fe/Cr catalysts. This reaction can also
be catalyzed
by Mo, Ni and further elements. Noble metals on cerium oxides have likewise
been
described a number of times as catalysts for this reaction.
The shift reaction not only leads to removal of the catalyst poison CO but
also
increases the proportion of the desired product H2 in the fuel stream. It is
therefore
important that a catalyst for the HTS catalyzes the production of H2 from CO
and H20
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but does not catalyze reactions which lead to elimination or depletion of the
desired
product H2. Such reactions include, in particular, methanation which can be
observed
over nickel catalysts at high temperatures and over noble metal catalysts even
at
temperatures above 350 C. This involves two reaction paths:
CO + 3 H2 ---> CH4 H20
CO2 + 4 H2 ¨> CH4 + 2 H20
Both reactions consume the desired product H2 and therefore reduce the
hydrogen
yield.
Processes and catalysts which give a very high yield of hydrogen and display a
very
low tendency for methanation to occur are known from the prior art.
EP 1 571 125 A2 discloses a catalyst for separating carbon monoxide from
hydrogen
gas. This comprises an oxidic support material comprising zirconium dioxide,
titanium
dioxide, aluminum oxide, silicon dioxide, silicon dioxide-aluminum oxide,
zeolites and
cerium oxide. Platinum is present as catalytically active metal. Furthermore,
alkali
metals such as lithium, sodium, potassium, rubidium or cesium can be present
as
further inorganic compounds so as to improve the activity of the catalyst for
removing
carbon monoxide by conversion into carbon dioxide in the water gas shift
reaction. The
catalytically active metal is, according to EP 1 571 125 A2, present in the
catalyst in an
amount of 2% by weight.
WO 2005/072871 A1 discloses a catalyst for the water gas shift reaction which
comprises metallic particles and particles of metal oxide. Suitable metal
oxides are, for
example, cerium oxide, titanium dioxide, iron oxide, manganese oxide or zinc
oxide.
Suitable metal particles are, for example, gold or platinum and are present in
an
amount of from 0.5 to 25% by weight, based on the oxidic material.
US 2006/0002848 A1 discloses a catalyst which has a support material composed
of,
for example, aluminum oxide, titanium dioxide, silicon dioxide, zirconium
dioxide or a
combination thereof. Furthermore, alkali or alkaline earth metals and also
metals
selected from among lead, bismuth, polonium, magnesium, titanium-vanadium-
chromium, manganese iron, nickel or cobalt, etc., can be present.
Catalytically active
metals present are, for example, platinum, palladium, copper, rhodium, etc.
EP 1 908 517 A1 discloses a catalyst for converting H20/carbon monoxide into
hydrogen and the use of this catalyst for increasing the concentration of
hydrogen in a
stream used for supplying a fuel cell. This catalyst is a solid comprising an
active phase
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3
comprising elements of group VIII on a support material comprising aluminum
oxide,
silicon dioxide, zirconium dioxide or mixtures thereof and a promoter from the
group of
the rare earths, for example lanthanum or cerium.
US 2005/0207958 A1 discloses a process for reducing the amount of carbon
monoxide
in a water gas shift reactor without formation of methane. A catalyst having a
support
material based on cerium oxide and zirconium oxide or cerium oxide and
lanthanum
oxide is used for this purpose. As promoters to avoid methanation, use is made
of
copper, manganese, iron compounds or combinations. Further promoters can be
alkali
or alkaline earth metals. The amount of platinum present on the catalyst is at
least 1%
by weight.
US 2005/0191224 A1 discloses a catalyst for separating off carbon monoxide
from
hydrogen gas. The catalyst used for this purpose has a support composed of
metal
oxide and has a platinum component and an alkali metal applied to this
support.
According to this document, zirconium dioxide, titanium dioxide, aluminum
oxide,
silicon dioxide, silicon dioxide-aluminum oxide, zeolites or cerium oxide, for
example,
are suitable as support material.
It was therefore an object of the invention to find an active catalyst which
can be used
over a wide temperature range and forms little methane. The catalyst should
ideally
have a low noble metal input.
Catalysts comprising noble metals are produced either by impregnating a shaped
support material with metal salt solutions of the noble metal component or by
impregnating the support powder and subsequently shaping it. It was therefore
a
further object of the invention to provide a process in which very little
noble metal
component is deposited in places inaccessible to the reaction.
The objects are achieved according to the invention by a catalyst comprising
at least
one noble metal in an amount of from 0.001 to 1.10% by weight, based on the
total
weight of the catalyst, at least one alkali metal and/or alkaline earth metal
and at least
one dopant selected from the group consisting of Fe, Cr, Cu, Zn and mixtures
thereof
on a support material.
The present invention further comprises a process for producing such a
catalyst and
also a process for converting a gas mixture comprising at least carbon
monoxide and
water into hydrogen and carbon dioxide using such a catalyst.
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The embodiments of the present invention may be found in the claims, the
description
and the examples. It goes without saying that the abovementioned features and
the
features still to be explained below of the subject matter of the invention
can be used
not only in the combinations indicated in each case but also in other
combinations
without going outside the scope of the invention.
It has surprisingly been found that when a supported noble metal catalyst
which has at
least one noble metal in an amount of from 0.001 to 1.10% by weight, based on
the
total weight of the catalyst, at least one alkali metal and/or alkaline earth
metal and at
least one dopant selected from the group consisting of Fe, Cr, Cu, Zn and
mixtures
thereof on a support material is used, the water gas shift reaction can be
carried out
successfully in a wide temperature range and undesirable methanation is
suppressed,
particularly at elevated temperatures as occur in the HTS. It is precisely the
combination of features of the catalyst of the invention which gives the
advantages
mentioned.
It is known that an increase in the shift activity combined with an increased
tendency
for methanation to occur is brought about in a noble metal-comprising shift
catalyst by
addition of, for example, sodium. A reduction in the shift activity combined
with a
decreased tendency for methanation to occur is brought about by addition of,
for
example, iron. For this reason, an optimum has to be found between addition
of, for
example, iron and alkali metal which both gives a satisfactory shift activity
and
suppresses the tendency for methanation to occur to a sufficient extent.
The catalyst of the invention comprises at least one noble metal and at least
one alkali
metal and/or alkaline earth metal, in each case in specified amounts, and also
a dopant
comprising at least one element selected from the group consisting of Fe, Cr,
Cu, Zn
and mixtures thereof on a support material.
The at least one noble metal is preferably selected from the group consisting
of Au, Pt,
Pd, Rh and Ru. Particular preference is given to using Pt. Combinations of Pt
with one
or more of the noble metals mentioned or combinations of one or more of the
noble
metals mentioned without Pt are also advantageous.
The present invention particularly preferably provides the catalyst according
to the
invention in which the noble metal is selected from the group consisting of
Au, Pt, Pd,
Rh, Ru and mixtures thereof. Very particular preference is given to using Pt
as noble
metal; in particular, Pt is preferably present as sole noble metal on the
catalyst of the
invention.
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The concentration of the at least one noble metal is, according to the
invention,
advantageously from 0.001 to 1.10% by weight, preferably from 0.01 to 1.00% by
weight, particularly preferably from 0.1 to 0.99% by weight, for example from
0.1 to
0.96% by weight, in each case based on the total weight of the catalyst. The
specific
combination of features of the catalyst of the invention makes it possible to
use very
small amounts of expensive noble metal and nevertheless achieve a high
catalytic
activity.
According to the invention, Li, Na, K, Rb, Cs, Mg, Ca and/or Sr are preferably
used as
at least one alkali metal and/or alkaline earth metal. Particular preference
is given to Li,
Na, K and Rb, in particular Na or K.
The present invention therefore particularly preferably provides the catalyst
of the
invention in which the alkali metal and/or alkaline earth metal is selected
from the
group consisting of Li, Na, K, Rb, Cs, Mg, Ca, Sr and mixtures thereof.
In a preferred embodiment, the concentration of the at least one alkali metal
and/or
alkaline earth metal is from 1.0 to 4.0% by weight, particularly preferably
from 1.2 to
4.0% by weight, very particularly preferably from 1.8 to 3.5% by weight, in
particular
from 2.0 to 3.2% by weight, in each case based on the total weight of the
catalyst. In a
further preferred embodiment, from 1.2 to 3.5% by weight, based on the total
weight of
the catalyst, of K or Na is used.
The present invention therefore provides, in a preferred embodiment, the
catalyst of the
invention in which the at least one alkali metal and/or alkaline earth metal
is present in
an amount of from 1.0 to 4.0% by weight, based on the total catalyst.
As further component, the catalyst of the invention comprises at least one
dopant
selected from the group consisting of Fe, Cr, Cu, Zn and mixtures thereof.
Very
particular preference is given, according to the invention, to using iron as
dopant. In
particular, exclusively Fe is used as dopant.
In the catalyst of the invention, the at least one dopant, in particular iron,
is present in a
concentration of generally from 0.01 to 5% by weight, preferably from 0.05 to
2.5% by
weight, particularly preferably from 0.1 to 1.5% by weight, in each case based
on the
total weight of the catalyst.
Apart from the at least one alkali metal and/or alkaline earth metal and the
at least one
dopant, the catalyst of the invention can comprise further dopants, for
example rare
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earth metals and/or main group elements of groups 13 to 15. Such further
dopants can
have total concentrations of not more than 15% by weight.
Suitable support materials for the purposes of the invention are all materials
which can
customarily be used for these purposes in catalyst chemistry and have a
sufficiently
high BET surface area.
The BET surface area should advantageously be at least 50 m2/g.
Preference is given to using support materials comprising combinations of
lanthanide
oxides and transition metals, particularly preferably Ce/Zr oxide. Here, the
ratio of Ce
oxide to Zr oxide should advantageously be 15 - 25 : 85 - 75% by weight, in
each case
based on the total weight of the support material. In an advantageous
embodiment, the
Ce/Zr oxide support material contains further oxides as dopants, for example
A1203
and/or La oxide. For example, a ratio of A1203 to Ce/Zr oxide which is
preferred
according to the invention is 5 - 20 : 95 - 80, particularly preferably 8 - 12
: 92 - 88, for
example 10: 90.
The amount of La oxide (La203) can be, for example, from 1 to 10% by weight,
preferably from 3 to 8% by weight, particularly preferably from 4 to 6% by
weight, in
each case based on the total weight of the support material.
The present invention therefore particularly preferably provides the catalyst
of the
invention in which the support material comprises at least Ce and/or Zr. In a
preferred
embodiment, the present invention provides the catalyst of the invention in
which the
support material additionally comprises La and/or Al.
In a particularly preferred embodiment, the present invention provides the
catalyst of
the invention in which Pt is present as noble metal, the alkali metal and/or
alkaline
earth metal is selected from among Li, Na, K, Rb, Cs, Mg, Ca, Sr and mixtures
thereof,
the dopant is Fe and a support material comprising Ce and/or Zr is present.
The
present invention particularly preferably provides this catalyst according to
the
invention in which the support material additionally comprises La.
According to the invention, the components present or optionally present in
the catalyst
of the invention, i.e. the abovementioned noble metals, alkali metals and/or
alkaline
earth metals, dopants and support materials can be present in elemental and/or
oxidic
form.
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In a further preferred embodiment, the present invention provides the catalyst
according to the invention in which the at least one noble metal, in
particular Pt, is
present in an amount of from 0.001 to 1.10% by weight, preferably from 0.01 to
1.00(3/0
by weight, particularly preferably from 0.1 to 0.99% by weight, for example
from 0.1 to
0.96% by weight, the at least one alkali metal and/or alkaline earth metal, in
particular
Na or K, is present in an amount of from 1.2 to 4.0% by weight, preferably
from 1.8 to
3.5% by weight, particularly preferably from 2.0 to 3.2% by weight, and the at
least one
dopant, in particular Fe, is present in an amount of from 0.05 to 2.5% by
weight,
particularly preferably from 0.1 to 1.5% by weight, in each case based on the
total
weight of the catalyst, and the support material comprises at least Ce and/or
Zr.
Very particularly preferred embodiments of the present invention comprising
specific
combinations of noble metal, alkali metal and/or alkaline earth metal, dopant
and
support material are disclosed in the examples.
It is precisely the combination according to the invention of noble metal,
alkali metal
and/or alkaline earth metal, dopant and support material, especially in
combination with
the specified amounts, which give a catalyst which, when used in a shift
reaction,
displays a very high reactivity combined with a very high efficiency. The high
reactivity
of the catalysts of the invention can be shown, for example, by the fact that
the
aforesaid shift reaction takes place with virtually complete thermodynamically
possible
conversion even at a relatively low temperature. Furthermore, the particularly
high
efficiency of the catalyst of the invention can be shown by the fact that the
catalyst
displays only a small tendency for methanation to occur in the shift reaction,
i.e. only a
small proportion of the hydrogen formed is reacted by formation of methane.
It goes without saying that the abovementioned features and features still to
be
indicated below of the catalyst can be employed not only in the combinations
and value
ranges indicated but also in other combinations and value ranges within the
boundaries
of the main claim without going outside the scope of the invention.
The catalyst of the invention can be produced by impregnation of the support
material
with the individual components. In a further advantageous production variant,
the active
components are applied to pulverulent support material which is then at least
partly
kneaded and extruded. It is also possible to combine the production variants
with one
another and, for example, apply only part of the active components to the
pulverulent
support material, knead and extrude the latter and then apply the remaining
active
components or the remaining partial amounts thereof.
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The active components are preferably used in the form of their salts or their
oxides.
Salts which are suitable for the purposes of the invention are, for example,
oxides,
nitrates, hydroxides, acetates, acetylacetonates, carbonates, nitrosyl
nitrates or halides
such as fluorides, chlorides, bromides and iodides.
To ensure good accessibility of the noble metal, the components are, in an
advantageous embodiment, applied onto the support material. Since various
metal
salts can usually not be applied in parallel due to conditions which have to
be adhered
to, for example pH, concentrations, etc., a catalyst having various promoters
is often
but not exclusively produced in a plurality of impregnation steps, for example
two
impregnation steps, which are carried out in succession.
The introduction of the active component by application to the support
material can be
carried out in a conventional way, e.g. as washcoat on a monolith.
lf, according to further advantageous embodiments, the active material is
firstly applied
at least partly to the support material, preferably pulverulent support
material, and then
kneaded and subsequently extruded, the kneading and extrusion of the support
material with the active compositions can be carried out in a conventional way
using
known apparatuses.
The present invention therefore provides, in particular, a process for
producing the
catalyst of the invention, wherein the at least one noble metal, the at least
one alkali
metal and/or alkaline earth metal and the at least one dopant are applied as
solution or
dispersion to the support material
Or
part or all of the at least one noble metal, the at least one alkali metal
and/or alkaline
earth metal and/or the at least one dopant is applied as solution or
dispersion to a
support material and this support material is mixed with the remaining part of
the
components.
Contrary to the assumption that the relative activity should be lower in the
case of a
directly kneaded catalyst because of the homogeneous distribution of the
active
components over the entire volume of the catalyst particles compared to a
catalyst
having the same active composition but produced by impregnation, a similar
activity
has been found according to the present invention.
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The production of shaped bodies from pulverulent raw materials can be carried
out by
conventional methods known to those skilled in the art, for example tableting,
aggregation or extrusion, as described, inter alia, in Handbook of
Heterogeneous
Catalysis, Vol. 1, VCH Verlagsgesellschaft Weinheim, 1997, pages 414-417.
Auxiliaries known to those skilled in the art, e.g. binders, lubricants and/or
solvents, can
be added during shaping or application.
The production processes described are simple and inexpensive. The catalyst of
the
invention is highly active in respect of the shift reaction but suppresses the
methanation
reaction; for example, a methane content of less than 100 ppm, preferably less
than
50 ppm (in each case at 350 C) and less than 500 ppm, preferably less than 300
ppm
(in each case at 450 C) is achieved using the catalyst of the invention.
The catalyst described can be used in the process of the invention for
converting a gas
mixture comprising at least carbon monoxide and water into hydrogen and carbon
dioxide.
The process can be carried out under the usual conditions of a shift reaction,
both in
the LTS range at temperatures of usually 150 - 280 C and in the HTS range at
temperatures of usually 280 - 550 C.
Owing to the low tendency for methanation to occur when the catalyst of the
invention
is used, even at high temperatures, this catalyst is particularly useful for
the HTS in
which the previous catalysts of the prior art are unsuitable. The shift
reaction according
to the invention proceeds particularly successfully in a temperature range
from 180 to
550 C. It is therefore possible and advantageous to use the catalyst of the
invention
both in the stage of the HTS and in the stage of the LTS.
The catalyst of the invention also allows a reduction to only one shift stage
which can
then be carried out at a moderate temperature, for example from 230 C to 450
C,
since the high activity of the catalyst at low temperatures still allows good
conversions.
The process of the invention for reducing the concentration of carbon monoxide
(CO)
by the process of a shift reaction over the highly active shift catalyst of
the invention is
carried out in conventional apparatuses and under customary conditions for
carrying
out a shift reaction, as are described, for example, in Handbook of
heterogeneous
catalysis, 2nd edition, Vol. 1, VCH Verlagsgesellschaft Weinheim, 2008, pages
354-
355, and with a process gas comprising CO and water being passed over the
catalyst.
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The process gas used is a gas mixture which usually comprises further gases,
e.g.
hydrogen, carbon dioxide and nitrogen, in addition to the carbon monoxide and
hydrogen which are reacted in the shift reaction described.
The present invention therefore also provides for the use of the catalyst of
the invention
for converting carbon monoxide and water into carbon dioxide and hydrogen.
Furthermore, the present invention provides a process for converting a gas
mixture
comprising at least carbon monoxide and water into carbon dioxide and hydrogen
using a catalyst according to the invention.
Figure:
Figure 1 shows an illustrative measurement scheme. Here, the abbreviations
have the
following meanings:
A amount of CO at the reactor outlet in ppm
B methane content in ppm
T temperature in C
MG, methane content at 350 C in ppm
MG2 methane content at 450 C in ppm
The invention is illustrated by the following examples without these examples
constituting any restriction:
Examples
Catalysts according to the invention and catalysts serving as comparison are
produced
by the following methods:
1. Production by impregnation (I):
The catalysts according to the invention and the comparative catalysts can be
produced by impregnation, as is shown by the following example of the
production of a
catalyst:
Starting materials:
Ce/Zr oxide extrudates 1.5 mm 1040 g
(water uptake (WU): 0.34 cm3/g)
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Pt nitrate solution 83 g
(w pt: 12.9 /0)
Fe(NO3)3 x 9 H20 15 g
Fe203: 19.88 0/0)
KOH 40% strength 72 g
(w K20: 33.68 %)
Procedure:
The required amount of iron nitrate is dissolved in the indicated amount of
platinum
nitrate solution and diluted with distilled H20 to a volume corresponding to
90% of the
water uptake of the Ce/Zr support material. The extrudates are placed in a
vessel and
spray-impregnated with the platinum/iron nitrate solution with circulation.
After
impregnation, the extrudates are circulated for a further 5 minutes, then
dried and
subsequently calcined. In the next preparation step, potassium hydroxide
solution is
diluted with distilled H20 to a volume corresponding to 90% of the water
uptake of the
Pt/Fe-doped extrudates obtained. These extrudates are subsequently spray-
impregnated with the dilute potassium hydroxide solution obtained with
continual
circulation. After impregnation, the extrudates are again circulated for a
further 5
minutes, then dried and subsequently calcined.
Drying: 4h at 200 C in a convection drying oven
Calcination: 2h at 500 C
Weight of product: 1001.8 g
Doping obtained: 0.9 g of Pt /100 g of catalyst
0.2 g of Fe/100 g of catalyst
2.0 g of K/100 g of catalyst
2. Production by kneading (K):
The catalysts according to the invention and the comparative catalysts can be
produced by kneading, as is shown by the following example of the production
of a
catalyst:
Starting materials:
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Ce/Zr oxide - Extrudates 1.5 mm 155 g
(water uptake (WU): 0.34 cm3/g)
Pural SB 22 g
Platinum nitrate solution (w pto: 14.02%) 13 g
Fe(NO3)3 x 9 H20 (w Fe203: 19.88 %) 2.5 g
KOH 40% strength (w K2O: 33.68%) 6.1 g
HNO3 65% strength 7.1 g
Procedure: The Ce / Zr oxide powder is placed together with the Pural SB in
a
kneader. The nitric acid diluted with distilled H20 to a total volume of
20 ml is slowly added and the mixture is kneaded for 10 minutes. The
iron nitrate is subsequently dissolved in the platinum nitrate solution,
diluted with distilled H20 to a total volume of 30 ml, added and the
mixture is kneaded for another 5 minutes. The undiluted potassium
hydroxide solution is subsequently added and the mixture is kneaded
for another 10 minutes. Distilled H20 is added in small portions until a
plastic composition is formed. The plastic composition is shaped by
means of an extruder to give 1.5 mm extrudates.
Total consumption of distilled H20: 69 ml (comprises the distilled H20
for diluting the HNO3 and the Pt / Fe solution)
Pressing pressure: 60 bar
Kneading time: 49 minutes
Drying: 4 hours at 200 C in a convection drying oven
Calcination: 2 hours at 500 C in a convection furnace
Doping obtained: 0.9 g of Pt /100 g of catalyst
0.2 g of Fe /100 g of catalyst
1.0 g of K /100 g of catalyst
3. Testing of the catalysts:
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To demonstrate the suitability of the catalysts produced, these are used in a
shift
reaction. Testing is carried out as follows:
1. Catalyst installation: 15 ml of catalyst (bed) or from 8 to 12 ml (volume
of a
monolith) are installed in the reactor,
2. Testing that the total apparatus is free of leaks after installation of the
catalyst
and before start-up,
3. Heating to 220 C and simultaneous reduction of the catalyst using a 1:1
mixture
of H2 and N2,
4. On reaching a temperature of 220 C, this is maintained for 5 minutes and
the test
is then started,
5. Start data recording,
6. Start temperature program, i.e. heat from 220 C to 450 C in 600 minutes
(cont.),
7. Maintain at 450 C for 20 minutes,
8. Cooling from 450 C to 220 C in 600 minutes (cont.).
The composition of the reaction gas used for testing is:
7% by weight of CO,
7% by weight of CO2,
33% by weight of H2,
27% by weight of N2 and
26% by weight of H20
The GHSV over the catalyst is 12279/h during testing. This test variant will
hereinafter
be referred to as test method M.
As an alternative to this test method M, it is possible, for example, to
change the
temperature program, for example by reducing the final temperature to 380 C at
an
initial temperature and heating rate ( C/min) which are unchanged from method
M.
The following apparatuses are used:
- Heating: Convection furnace with temperature range up to max. 600 C,
- Temperature measurement against the outside of the reactor,
- Gas metering: Mass flow controller (Brooks)
- Water metering: Liquid flow
- Analytical instrument for CO and CO2: Siemens Ultramat 23
- Analytical instrument for methane: FID from J.U.M. Engineering Model 3-300A
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- Pressure regulation by means of Reco pressure regulating valve
- Linseis 36 channel recorder as interface for data storage
- Data evaluation by Software
The following parameters are measured:
1. Temperature T1 (temperature with the lowest CO content at the beginning of
the
first ramp [ C])
2. Temperature T2 (temperature with the lowest CO content after the first
temperature ramp [ C])
3. Methane content MG1 in ppm at a temperature of 350 C
4. Methane content MG2 in ppm at a temperature of 450 C
5. Method M (ramp from 220 to 440 C, Chevron etc.)
4. Results
The results for the catalysts according to the invention and the catalysts
produced for
comparison are shown in Table 1 below:
,
PF 70061
15 .
Table 1: Results of the various catalysts according to the invention and the
catalysts for comparison
Pt Alkali metal/alkaline Production3-) T, T2
No. Doping
MG, [ppm] MG2[13Pm] M
[% by weight] earth metal'
[ C] [ C]
-
0.95 Fe; 0.2 K; 2 I 260.8 301.18
30.62 278.5 x
1
2 0.95 Fe; 0.2 K; 1 K 260
300 71.33- only 380 C
-
3 0.9 Fe; 0.2 K; 1 K 270
305 67.39 - only 380 C
n
-
4 0.8 Fe; 0.2 K; 1 K 280
310 54.49 only 380 C
0
I.)
0.9 Fe; 0.2 K; 2 K 292.44 345.22 28.66
145.54 x co
0
u-i
I.)
6 0.35 Fe; 0.2 K; 2 I . 320
325 19.67 285.33 x u-i
C741 0.35 Fe; 0.07 K; 0.7 I 330
345 180.69 1383.89 x I.)
0
H
8 0.95 Fe; 0.3 K; 2 I 268.66
280.96 48.62 216.3 x u.,
i
- 0
9 ' 0.95 Fe; 0.4 K; 2 I 285.22
314 17.77 101.96 x H
H
H
0.95 Fe; 0.25 K; 2 K 286.29 293.57
45.27 - x
-
11 0.95 Fe; 0.15 K; 2 K 284.81 285.2
68.98 - only 380 C
12 0.95 " Fe; 0.2 K; 3 I 262.48
321.29- - - only 380 C
C1341 0.95 Fe; 0.2 - I 282.23
307.46 291.56 1885.45 x
C1441 0.95 Fe; 0.5 - I 296.27
319.63 77.23 329.51 x
C1541 0.95 Fe; 0.8 - I 315.15
351.55 68.31 246.63 x
C1641 0.95 Fe; 1.0 Na; 2 I 310.87
331.72 - 30.07 43.38 x
17 0.95 Fe; 0.5 Na; 2 I 310.38
343.08 54.52 208.73 x
C1841 0.95 Fe; 1.0 Na; 2 K 331.61
363.68 30.89 75.98 x
,
PF 70061
.
16
C194) 0.95 - K; 5 292.74
346.69 72.06 913.61 x
C2041- 0.95 Fe; 5 Ni; 1 I 359.03
358.8 25698.78 32595.57 x
21 0.95 Fe; 0.5 Li; 2 l 285.63
297.78 104.51 786.67 x
22 0.95 Fe; 0.5 Rb; 2 ' 2=
93.08 304.74 52.34 179.14 x
23 0.95 Fe; 0.5 Cs; 2 l 259.89
- 109.03 554.88 x
C244) 0.95 Mn; 0.2 K; 2 l 276.89
314.25 291.41 4111.02 x
C254) 0.95 Co; 0.2 K; 2 l 304.19
318.84 590.55 4731.53 x
26 0.95 Fe; 0.2 Mg; 2 l 321.44
311.44 80.09 694.34 x
n
27 0.95 Fe; 0.2 Ca; 2 ' 3=
00.59 323.29 143.21 1194.77 x
2
28 0.95 Fe; 0.2 Cs; 2 l 293.18
294.92 178.32 1626.74 x
29 0.95 Fe; 0.2 K; 2 l 281.56
307.02 - - x
I.,
u-,
30 0.95 Fe; 0.5 ' K; 2 282.83
209.57 24.15 108.47 x
I.,
0
C314) 0.95 Fe; 5 - - 2=
65.95 298.15 43.72 388.31 x F-,
UJ
I
0
H
1)
I
element; Amount [% by weight] are reported
H
H
2) element; Amount [% by weight] are reported
3) I = impregnation; K = kneading
4) comparative experiment
