CA2112519A1 - Catalytic process for producing synthesis gas - Google Patents

Catalytic process for producing synthesis gas

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Publication number
CA2112519A1
CA2112519A1 CA002112519A CA2112519A CA2112519A1 CA 2112519 A1 CA2112519 A1 CA 2112519A1 CA 002112519 A CA002112519 A CA 002112519A CA 2112519 A CA2112519 A CA 2112519A CA 2112519 A1 CA2112519 A1 CA 2112519A1
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Prior art keywords
catalytic
oxygen
methane
fed
beds
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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CA002112519A
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French (fr)
Inventor
Domenico Sanfilippo
Luca Basini
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SnamProgetti SpA
Original Assignee
Domenico Sanfilippo
Luca Basini
Snamprogetti S.P.A.
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Application filed by Domenico Sanfilippo, Luca Basini, Snamprogetti S.P.A. filed Critical Domenico Sanfilippo
Publication of CA2112519A1 publication Critical patent/CA2112519A1/en
Abandoned legal-status Critical Current

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    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
    • C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
    • C01B3/382—Multi-step processes
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    • C01B3/00—Hydrogen; Gaseous mixtures containing hydrogen; Separation of hydrogen from mixtures containing it; Purification of hydrogen
    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
    • C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
    • C01B3/386—Catalytic partial combustion
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    • C01B3/02—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen
    • C01B3/32—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air
    • C01B3/34—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents
    • C01B3/38—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts
    • C01B3/40—Production of hydrogen or of gaseous mixtures containing a substantial proportion of hydrogen by reaction of gaseous or liquid organic compounds with gasifying agents, e.g. water, carbon dioxide, air by reaction of hydrocarbons with gasifying agents using catalysts characterised by the catalyst
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/0205—Processes for making hydrogen or synthesis gas containing a reforming step
    • C01B2203/0227—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step
    • C01B2203/0238—Processes for making hydrogen or synthesis gas containing a reforming step containing a catalytic reforming step the reforming step being a carbon dioxide reforming step
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/02—Processes for making hydrogen or synthesis gas
    • C01B2203/025—Processes for making hydrogen or synthesis gas containing a partial oxidation step
    • C01B2203/0261—Processes for making hydrogen or synthesis gas containing a partial oxidation step containing a catalytic partial oxidation step [CPO]
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    • C01—INORGANIC CHEMISTRY
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08—Methods of heating or cooling
    • C01B2203/0805—Methods of heating the process for making hydrogen or synthesis gas
    • C01B2203/0838—Methods of heating the process for making hydrogen or synthesis gas by heat exchange with exothermic reactions, other than by combustion of fuel
    • C01B2203/0844—Methods of heating the process for making hydrogen or synthesis gas by heat exchange with exothermic reactions, other than by combustion of fuel the non-combustive exothermic reaction being another reforming reaction as defined in groups C01B2203/02 - C01B2203/0294
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/08—Methods of heating or cooling
    • C01B2203/0872—Methods of cooling
    • C01B2203/0883—Methods of cooling by indirect heat exchange
    • C—CHEMISTRY; METALLURGY
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/10—Catalysts for performing the hydrogen forming reactions
    • C01B2203/1005—Arrangement or shape of catalyst
    • C01B2203/1011—Packed bed of catalytic structures, e.g. particles, packing elements
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/10—Catalysts for performing the hydrogen forming reactions
    • C01B2203/1041—Composition of the catalyst
    • C01B2203/1047—Group VIII metal catalysts
    • C01B2203/1064—Platinum group metal catalysts
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/10—Catalysts for performing the hydrogen forming reactions
    • C01B2203/1041—Composition of the catalyst
    • C01B2203/1047—Group VIII metal catalysts
    • C01B2203/1064—Platinum group metal catalysts
    • C01B2203/107—Platinum catalysts
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    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/10—Catalysts for performing the hydrogen forming reactions
    • C01B2203/1041—Composition of the catalyst
    • C01B2203/1082—Composition of support materials
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    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/12—Feeding the process for making hydrogen or synthesis gas
    • C01B2203/1205—Composition of the feed
    • C01B2203/1211—Organic compounds or organic mixtures used in the process for making hydrogen or synthesis gas
    • C01B2203/1235—Hydrocarbons
    • C01B2203/1241—Natural gas or methane
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/14—Details of the flowsheet
    • C01B2203/141—At least two reforming, decomposition or partial oxidation steps in parallel
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B2203/00—Integrated processes for the production of hydrogen or synthesis gas
    • C01B2203/80—Aspect of integrated processes for the production of hydrogen or synthesis gas not covered by groups C01B2203/02 - C01B2203/1695
    • C01B2203/82—Several process steps of C01B2203/02 - C01B2203/08 integrated into a single apparatus
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Abstract

"CATALYTIC PROCESS FOR PRODUCING SYNTHESIS GAS"
Abstract Catalytic process for producing synthesis gas by starting from methane, oxygen and, possibly carbon dioxide and water, in which a noble metal catalyst supported on a solid carrier is used, which catalyst is arranged as a cascade of a plurality of catalytic beds, and the process is carried out under adiabatic conditions:
-- by feeding the gas reactant stream upstream of the first catalytic bed and removing heat by heat exchange between the catalytic beds arranged in cascade, or -- by introducing the gas reactant stream partially upstream from the first catalytic bed and partially, as a cold stream, between the catalytic beds arranged in cascade.

Description

"CATALYTIC PROCESS FOR PRODUCING SYNTHESIS GAS"
The present invention re~ates to the production of synthesis gas ("syngas") by starting from methane, oxygen and, possibily, carbon dioxlde and ~ater, ~hich process is carried out over a plurality of catalytic beds arranged in cascade and feeding the feedstock to the process as a plurality of subdivided streams fed upstream from each catalytic bed.
The synthesis gas, also referred to as "syngas"
is prevailingly constituted by a gas mixture of CO and H2. Producing the syngas mixture is presently the key passage in the technology of production of fuels for motor vehicles by means of Fischer-Tropsch synthesis, in the technology of production of methanol and higher alcohols, and in ammonia synthesis. The investment costs and energy consumptions for operating the production units for syngas are estimated to be approximately 60% of total costs of the above listed processes.
Syngas is presently produced by means of steam reforming or auto thermal reforming or processes of partial, non-catalytic, oxidation of hydrocarbons. The reactions which constitute the base of these conversions are the following~
:
CnHo + n/2 02 ~~~> n CO + m/2 H2 Cl]
CnH~ + n H20 -~-> n CO + (m + n/2) H2 C2]
Cn H~ + n C02 ~~~> 2n CO + m/2 H2 C3]
~: Cn H~ ~~~> Cn + m/2 H2 C4]
2CO ---> C ~ C02 C5]
C0 + H20 -~~> H2 + CO2 C6~

-- 2. 2 1 1 2 5 1 9 ;
~ . ~
. ~.....
In greater detail, the steam reforming processes catalytically convert hydrocarbonslsteam mixtures tH20:C=2.5 - 3.5~, yielding C0/H2 mixtures ~ith an H2/C0 ratio ~hich typically is of round 3. The chemical reactions involved in the process are ~2~
. . , ~
C4-5] and C 6 The H20/C ratio in the reactant mixture is both determined by the temperature and pressure conditions under which the reactions are carried out, and by the need of inhibiting the coal formation reactions C4-5]
The commonly used catalysts in these processes are based on Ni supported on Al, Mg, Si oxides. These carriers display high characteristics of heat stability and mechanical strength. The reactions are carried out inside tubular reactors installed inside a combustion chamber. The pressures inside the tubes are typically comprised within the range of from 1 to 5 MPa, and the gas temperature at tube outlets typically is of round 8500C (reference is made, for ;~nstance~ ~o "Catalysis Science and Technology"; Vol. 5 (1984), chapter 1, J.R. Rostrup-Nielsen).
The non-catalytic partial oxidation processes are less ~idely used and are employed in order to convert mixtures of oxygen, hydrocarbons, steam and water into syngas ~ith Hz/C0 ratios of typically round 2. The chemistry of the process can be represented by the e~uations C1], C4]-C6]. The facilities installed heretofore by Texaco and Shell (see Hydrocarbon -trocessing; April 1990, page 9q) use adiabatic reactors inside ~hich the reactions are initiated at - . . ~

.: - : - ~

: ~ . .: . :.

."~ , ".~,, reactors inlet by means of a burner in ~hich total hydrocarbon combustion reactions ~7~ take place. These reactions produce large heat, steam and C02 amounts.
Heat causes reactions of cracking of unburnt S hydrocarbons and favours the steam C2] and C02 C3]
reforming reactions.
The operating temperatures are typically comprised within the range of from 1250 to 1500C, and the pressure is allowed to range from 3 to 12 MPa.
The processes of autothermal reforming are carried out inside adiabatic reactors to which mixtures of hydrocarbons, oxygen and steam are fed. In a first reaction zone, the reactions are initiated of total combustion of hydrocarbons, represented by the equation:
CnH~ + (n + m/2) 02 ~~~> n C02 + m/2 H20 [7]
In a second zone inside a catalytic bed, the steam C2] and C 02 C3] reforming reactions take place.
In the catalytic bed, nickel-based catalysts are used, the characteristics of which are analogous to those as described above for steam reforming processes. In the autothermal reforming, mixtures of H2/C0 having values ranging from those of steam reforming processes to those of non~
catalytic partial oxidation, are obtained.
~ - The temperature of ; the gas streams at reactor outlets is typically comprised within the range of from 950 to 10000C, but ~;~ the temperature of the zone in which the burner is installed is considerably higher. The pressure inside the reactors is comprised within the range of from 2 ~' `:

4 2112~19 :

to 4 MPa. - ~
:
One from the main drawbacks ~hich limit the possibilities of technological innovation in the definition of new catalyt;c reactors and ne~ processes routes for syngas production and use is determined by the coal formation reactions C4]-C5~. Coal formation is not tolerated in the catalytic processes for syngas production and is prevented from occurring by using reactants mixtures containing steam and/or oxygen.
According to the syngas production processes and the operating conditions, therefore, restraints exist as to the composition of the reactant mixture and, in particular, as to its steam and/or oxygen contents;
such restraints are generally expressed in terms of . . .
15 H20/C and Oz/C ratios. -;- ;`~
Extending the threshold values of composition of : . ~.
the reactant mixture, would make it possible innovative solutions to be designed for syngas production processes, because one might state tha~ the characteristics of the reactors and of the process schemes in syngas production facilities are the result of complex ;nteractions between the chemical properties of the catalysts and mechanical constraints to the characteristics of the materials used in the ~ ~ .,i.
25 reactors. ;
In Italian patent application No. 19,162 A/90, fiLed on January 26th, 1990, to the same Applicant's ` ` `
name, disclosed is a process for syngas production by ~ ; d starting from carbon dioxide and light hydrocarbons, in particular methane, over a supported catalyst based .

5 2112519 ~
~ " ., on a metal from pLatinum group. Furthermore, in Italian paten~ application No. 21,326 Al90, filed on August 29th, 1990, to same Applicant's name, disclosed is a process for syngas production by means of a first step, of non-catalytic combustion of hydrocarbons with oxygen, followed by a second step, of reforming, in which the oxidation products from the first step are brought into contact with a further amount of hydrocarbons, in the presence of a supported cataLyst of a metal from platinum group.
The present Applicant found now, according to the present invention, that the use of noble metal catalysts considerably reduces the width of the regions inside which the coal formation reaction takes place and therefore makes it possible reaction mixtures with low H20/C (e.g., lower than 0.5) and 02/C ratios (e.g., lower than 0.5) to be used without that the coal formation reaction are initiated.
Such a finding makes it possible said catalysts to be used in a process for syngas production in a reaction system consisting of a plurality of adiabatic catalytic beds arranged in cascade, in which a differentiated feed of the reactant mixture is ~ . .
preferably provided, and in which the composition of : ~ :
said mixture at the inlet to said catalytic beds may even have values of H20/C and 02 /C ratios, which are lower than 0.5 and 0.5, respectively. Furthermore, a catalytic process which displays such characteristics -~
makes it possible syngas mixtures to be obtained 30 withour requiring that at its inlet a burner is ~;~

' ', ~

instaLled, because the combustion reactions are cataLyticaLLy initiated at Lou temperatures.
More particuLarly, the process for syngas production, carried out on a pluraLity of adiabatic cataLytic beds in cascade, according to the present invention, enables the foLlowing advantageous effects to be accompLished~
-- reduction of temperature gradients and also of the highest temperature values inside said catalytic ;,.,: - ~
beds, with consequent lower thermal stresses being applied to the materiaLs; in that ~ay, traditional building materiaLs can be used, with consequent savings in investment costs;
-- possibility of directLy obtaining, at the outlet from the catalytic partial oxidation reactor, syngas with H2/C0 ratios comprised within the range of from 0.9 to 3, without that the adjustment of the vaLue of such a ratio requires that a further reactor for water gas shift (WGS) reactions ~6] is used;
-- possibiLity of avoiding using a burner at reactor inlet, with consequent saving in reactor investment costs;
-- improvement of heat efficiency of syngas production process, both as compared to the commerciaL
processes of non-cataLyzed partiaL oxidation -~: ~ . . ~ . .. :
processes, and as compared to autothermaL reforming processes; such an improvement is made possibLe because the configuration of the reactor makes it possibLe the heat recovery rates to ~e optimized, ~: _.. _~,._.,.~_., _. ,. _, . _. ,, . _, ,, ~.. ., .. . _ . .. _ . ,.. ..... ... ,. _.__. ~___ ._~.. ,.. ~ .. _ .. _. __.. _ ,._ .. _. __ .. _~_..
_~ .. _._.. _ . _ .. .... _ : . :

7 211251~
"~
by preventing the unnecessary~ extremely high temperatures ~hich occur inside the interior of the reactors (in particular at inlet regions) used in the exisiting processes;
-- possibility of kinetically controlLing the coal generation reactions and, therefore, of reducing the vaLues of HzO/C (steam mols/carbon mols) and 02 /C (oxygen mols/carbon mols) ratios in the reactant mixture;
-- possibility of optimizing the process conditions, with in each layer the conditions of maximaL
reaction speed being reached, with the catalyst amount being consequently decreased (decreasing the catalyst amount is a determinative factor when noble metal-based catalytic system are used).
In accordance therewith, the present invention relates to a catalytic process for preparing synthesis gas by starting from methane, oxygen and, possibily, carbon dioxide and water, characterized in that~
2û -- the catalyst used is a noble metal catalyst supported on a solid carrier, arranged as a~ ~L
plurality of fixed catalytic beds in cascade to `~
each other; ~ --- the gas feed stream contains methane, oxygen, carbon dioxide and water in the following molar proportions: r~
methane 1.0;
oxygen from û.2 to 1.0;
carbon dioxide from 0 to 3.û;
wate~ from 0 to 3.0; and , .::

2112519 ;~;

-- the process is carried out under adiabatic conditions;
by feeding the gas reactant stream upstream from the first catalytic bed and removing heat, by heat exchange between the catalytic beds arranged in cascade, or ~ ~ -by feeding the gas reactant stream partially upstream from the first catalytic bed and partially, as a cold stream, between the catalytic beds arranged in cascade, with said partial feeds being of same composition, or having different compositions from each other, with the proviso that methane is at least partially fed to the first catalytic bed and oxygen is subdivided between all of the catalytic beds.
The catalysts useful for the process according to ~ ~ -the present invention are constituted by one or more metals from platinum group, selected from Rh, Ru, Ir, Pt and Pd, supported on a carrier selected from aluminum, magnesium, zirconium, silicon, cerium and/or lanthanum oxides and/or spinels.
Said carrier can also be provided with surface-grafted silica moieties, and suitable processes for preparing such carriers with surface-grafted silica moieties are reported in the experimental examples supplied in the following in the present application, in the above mentioned Italian patent applications and in United Kingdom patent application ~B 2,240,284.
Preferred carriers for such catalysts are alumina and/or magnesium oxide, possibiLy provided with surface-grafted silica moieties.

9 2112519 -: ~

The catalysts of the first cataLytic bed contain rhodium in association with platinum or palladium, and the catalysts of the subsequent catalytic beds preferably contain two metals selected from rhodium, 5 ruthenium and iridium, with the overall percent ~t contents of noble metals in the supported catalyst being comprised ~ithin the range of from û.05 to 1.5X
by weight, and preferably of from 0.1 to 1% by weight. ;~
In order to be used as a stationary catalytic 10 bed, the catalysts will preferably be in granular form, with particle size comprised within the range of from 1 to 20 mm.
The catalytic beds used will be at least two, with their maximal number, dictated by practical 15 reasons, being of four or five. Preferably, the process will be carried out with either two or three catalytic beds in series to each other. These catalytic beds can be arranged inside a plurality of reactors arranged in series to each other, but 20 preferably, one single reactor containing a plurality ;-~
of catalytic beds will be used. -~
According to the present invention, to the catalytic beds a gas stream is fed ~hich contain methane and oxygen, and possibly also carbon dioxide 25 and/or water, preferably in the following molar ~-proportions:
methane 1.0; ; ~-~
oxygen 0.4-0.6;
carbon dioxide 0-1.0; and 30 water û-1Ø

'. . :,'':':~
-, 1o. ~:
2 ~ 1 2 5 1 9 As said hereinabove, the process is carried out ;
under adiabatic conditions by feeding the gas reactant stream totaLly upstream from the first bed and removing heat, by heat exchange, from points between ` ~ -S the catalytic beds arranged in cascade.
According to a preferred embodiment, the process is carried out under adiabatic conditions by feeding - ~`
the gas reactant stream partially upstream from the ~-first catalytic bed and partially, as a coLd stream, 10 between the catalytic beds arranged in cascade. The ` -;
gas streams fed to the individual catalytic beds can ~ -have the same composition, or compositions different ; ;
from one another. In the latter case, methane will be ~ ;3"'.
at least partially fed to the first catalytic bed and 15 the oxygen feed stream will suitably be subdivided --,: ~- :-between all catalytic beds.
In any case, by operating according to the , . ,.,..:, .
present invention, synthesis gas is obtained by the effect of partial methane oxidation, and, possibly, -~
also owing to reforming phenomena, as a function of the fed reactants. ~ -~
According to an embodiment of the present ;invention, to the first catalytic bed a gas stream is ~-fed which contains methane, oxygen, carbon dioxide and steam, and to the subsequent catalytic beds an oxygen stream is fed. Preferably, the process will be carried out with a moLar ratio of methane, carbon dioxide and ;~
water fed to the first catalytic bed, of 1:û.5-1:0.3 1, and with a total oxygen amount of 0.4-0.6 mols per 30 each methane mol, fed as subdivided streams to each of - -1 1 .
2112519 ~-~
ir the several caeaLytic beds.
According to another embodiment, to the first catalytic bed a gas stream is fed which contains methane and oxygen, and to the subsequent catalytic beds a mixture is fed which contains methane, oxygen and carbon dioxide. Preferably, the process will be carried out with a molar ratio of methane to oxygen fed to the catalytic beds of the order of 1:0.4, and with an amount of carbon dioxide of the order of 0.4 mols per each mol of methane.
According to a further embodiment, to the first catalytic bed, and to the subsequent ones, a gas stream is fed which contains methane, oxygen and carbon dioxide. The molar ratios of these reactants to each other will preferably be of the order of 1:0.6:0.7-0.8.
According to a further embodiment, to the first catalytic bed a gas stream is fed which contains methane, oxygen and carbon dioxide, and to the Z0 subsequent catalytic bed an oxygen stream will be fed.
The process will preferably be carried out with a molar ratio of methane to carbon dioxide fed to the first catalytic bed of 1:0.3-0.6, and with a total oxygen amount of 0.5-0.6 mol per each mol of methane, subdivided to the various catalytic beds.
It should be observed that according to the present disclosure, the term "oxygen" is understood to mean pure or substantially pure oxygen, or oxygen mixed with an inert gas, such as nitrogen, e.g., air.
In general, the process will be carried out with ' Z 2 1 1 2 ~ 1 9 inlet temperatures to the tirst bed of the order of 300-4000C and ~ith outlet temperatures from said first bed, of the order of 700-8700C. The inLet temperatures to the beds downstream from the first bed will be of the order of 450-7300C, and the outlet temperatures will be of the order of 770-8500C. The cooling bet~een two adjacent beds will cause a decrease in temperature of from 10OC, up to as high values as 420OC and will normally be of the order of 120-1700C. The pressures under which the process is carried out may generally be comprised within the range of from 0.1 to 10 MPa.
The space velocities, under the reaction conditions, may generally be comprised within the range of from 1,000 to 50,0ûO h-l and will normally be of the order of 5,000-20,000 h-~
8y operating under these conditions, the mixture recovered at the outlet from the last catalytic bed, will contain hydrogen and carbon monoxide in a molar ratio to each other comprised within the range of from 20 about 0.9 to about 3 and normally of from about 1 to about 2.3.
It should be observed that in the case of exothermic reactions like the reaction of partial hydrocarbon oxidation C1], the expected reactant 25 conversion rates as calculated by means of equilibrium thermodynamic computations, vary as a function of temperature, according to the trend schematically sho~n in Figure 1. On the other hand it is known (O.
Levenspiel, "Chemical Reaction Engineering", John Wiley and Sons, .

- 2 1 1 2 5 ~ 9 Inc., New York London) that the conversion rates, the reaction temperature and the reaction speed are m~tuaLly linked parameters. For exothermic reversible reaction (like the partial oxidation react;on C1 which are catalyzed in a "Plug-Flow" reactor, a temperature increase kinetically favours the transformation of the reactants into the reaction products, but, opposite to this trend, the temperature increase decreases the max;mal conversion rate which can be obtained. In these cases, the optimal temperature variation can be obtained in reactors with a plurality of adiabatic layers with intermediate coolings induced by means of heat exchanges with heat recovery, or by means of the introduction of "cold"
gas streams of reactants between the layers~ In Figure 1, "isospeed" curves are reported (i.e., curves along which the reaction speed remains constant with varying values of temperature and of reactants conversion), according to the typical trend of exothermic processes. The peak points of isospeed lines determine pairs of values of temperature (T) and conversion (Xa). The line which connects all of these points with each other (i.e., the line which makes it possible the maximal reaction speed values to be obtained with varying temperature) describes the optimal temperature progression for a Plug-Flow reactor in which an exothermic chemical process is being carried out.
~ Similar considerations may be made in the case of;~ endothermic processes. Such a curve can be e-perimentally followed by means of a catalytic, ., t~

`
14. 2112519 : .- ~ . ~. ..
adiabatic-layer reactor provided with a plurality of reaction zones separated by temperature adjustment zones, as in the case of the process disclosed herein.
:~- : . ~, ~;
The following experimental examples are reported in order to better illustrate the present invention.
E_3m~
A laboratory reactor is used wh;ch is provided w;th two reaction zones, to which two different catalysts are charged.
The reactor was so accomplished as to make it possible the reactants tmixtures of methane, oxygen, steam and carbon dioxide) to be fed both to the reactor head, directly to the first catalytic bed (first adiabatic layer), and in the separation zone between both catalytic beds (i.e., between the first and the second adiabatic layers).
The reactor is constituted by an alumina tube with an extremely low porosity and displaying high heat resistance and mechanical strength characteristics. The alumina tube was fitted into a steel jacket. Around the steel tube, in the region of both reaction zones, two resistors are installed, the function of ~hich is of compensating for the heat losses caused by the non-perfect adiabatic character of the reactor (this is a drawback which is impossible to remove in such a type of testing in smaL~-size laboratory reactors). Inside the alumina tube, there is fitted a thermocouple well. The steel sheath of the thermocouple ~ell was coated with a thin gold layer in order to prevent coal from being formed on its - '5 2112~19 ., . ~ .
surface. The temperatures inside both adiabatic layers ~
were measured with the aid of two thermocoupLes which could be longi~udinally moved along said beds~
The two catalysts used in these tests were 5 prepared according to the following procedures. -~
C 3 t _ l y _ _ _ _ f o r _ _ b e _ f i r s _ _ r e a _ _ i o n _ z o n _ _ ( _ i r s _ _ 3 d i a b 3 t l c 3Y__) Into a slurry constituted by a suspension of alpha-alumina in n-hexane, à solution of Rh4tC0)l2 and ~Pd(CsHsO2~z] in the same solvent, was added dropwise.
The solvent was then evaporated under vacuum and, after drying, the solid powder was pressed into . .: , ~. ~
pellets which, by crushing, yielded a granular solid -~
with maximal particle diameter comprised within the i5 range of from 2 to 2.5 mm. The catalyst volume charged to the first catalyt;c bed is of 5 cm3, the Rh content in the catalyst is of 0.1% by weight, the palladium content is of 0.5% by weight.
C3t3ly_t__or_tb___eçong_r_3Ç_1QD_Z-o-n--t--eç-o-ng-3gl3g3 l3y__) In this case, a typical carrier for steam -reforming catalysts was prepared, which contains ;
magnesium oxides and alumina (Mg/AL = 7l1 mol/mol), and was obtained by means of a process comprising~
(i) co-precipitating aluminum and magnesium -`
hydroxides, by increasing the pH value of an -`-aqueous solution of Mg(N03)z and AltN03)3.9HzO;
tii) filtering the precipitate off and washing it;
tii;) drying and calcining the precipitate at 4000C, - i tiv) "pelletizing" the solid powder;
", ..

16. 2 1 1 2 ~ i 9 (v) treating the pellets by further calcining them up to 1000OC and, after cooLing, crushing the pelLets in order to obtain a granular material with a maximal particle diameter of 2-2.5 mm.
The percent sodium level in the resulting carrier is lower than 0.1%. The carrier was then dispersed in a soLution of n-hexane into which a solution, in the same solvent, of Rh4(C0)12 and Rua(C0)l2 had been added dropwise. After evaporation and vacuum drying, a granular material was obtained which contained 0.1% by weight of Rh and 0.5% by weight of Ru. The catalyst volume charged to the second catalytic bed is of 5 cm~
Prior to the reaction, the catalysts were treated at the temperature of 5000C, with H2/N2 streams containing increasing hydrogen levels. Then, to the inlet to the first catalytic bed a stream was fed which contained CH~:COz :02 :H20 in molar ratios of 1:1:0.5:0.3. The total flowrate of feedstock fed to the first catalytic bed was of 50 Nl/hour, the gas stream inlet temperature was kept at 3000C, the inner reactor pressure was kept at 10 atm. Before entering the second adiabatic layer, the leaving stream from the first catalytic bed was mixed with a second stream of oxygen pre-heated at 3000C, fed at a flowrate of 2.3 Nl/hour.
In Table 1, the main features of this experiment are reported.
_A~jLE~
I-t-3-dl3-b3-i--l3 i: :

~ 17 2112~19 Catalyst~
-- composition: Rh (0,1%) + Pt (0~5X) on Al20 -- amount: S cc Inlet composition:
-- CH4:CO2 02:H20 = 1:1:0.5:0.3 tvolume ratios) . , ~ ....
Feed flowrate:
-- CH4 = 17.90 Nl/hour ;
-- COz = 17.90 Nl/hour ~- 02 = 8 70 Nl/hour ~--- H20 = 5 30 Nl/hour -- total = 50 00 NL/hour Temperatures P
-- ;nlet = 3000C ```~
-- outlet = 7450C
II-g--gi_ba_ Catalyst: ! --- composition Rh (0 1%)+Ru (0.5%) on MgAlOx ;
Inlet composition: ~ i -- gas product from the Ist layer + added 02 -- 02 feed flowrate: Z.30 Nl/hour Temperatures: `
-- inlet = 7300C
-- outlet = 8100C
_om eo i tioo_3t_rea__or_outl__:
% by mol Mols/hour ~;~ -- CH~ 5.20 0.16 -,~
-- CO2 23.46 0.73 -- HzO 21.59 0.67 `~

30-- H2 27.04 0.84 ~ 18. 2 1 1 2 ~ 1 9 -- C0 22.68 0.71 Molar ratio of H2:C0 at reactor outlet: 1.18:1. ~ ~
Ex_mel__2 '.:5~ ,.'' The same experimental devices and the same catalysts as disclosed ;n experiment 1 were used, by feeding to the inlet to the first catalytic bed a reactant stream with a total flo~rate of 50 Nl/hour and having the;~
composition CH4:C02:02:H20 = 1:0.5:0.4:1 and feeding, upstream from the second catalytic bed, a stream of~~
oxygen pre-heated at 3000C, with a flo~rate of 3 Nl/hour. -~
The main features of this second experiment are reported in Table 2 _ABLE__ I_t_3g13g3_ic_l3yer Catalyst:
-- composition: Rh (0,1%) ~ Pt (û,5X.) on Al20 -- amount: 5 cc Inlet composition:
ZO -- CH4 :C02 :02 :H20 = 1:0.5:0~4:1 (volume ratios) Feed flo~rate:
-- CHg = 17.20 Nl/hour -- C02 = 8.60 Nl/hour -- 02 = 7.00 Nl/hour ~
-- H20 = 17 20 Nl/hour - ---- total = 50.00 NL/hour Temperatures:
-- inlet = 300OC
~: : , -- outlet = 705OC
II_g__gi_b__i~ y_r -9. 2112519 Catalyst~
-- composition: Rh (O.lY.) + Ru (0.5%) on MgAlOY
-- amount: 3 cc ~".,.','!:,.'"
Inlet composition:
-- gas product from the Ist layer + added 02 -- Oz feed flowrate: 3.00 Nl/hour -~
Temperatures:
-- inlet = 6900C -~
-- outlet = 8050C
__mp__i_i_n____________outl_t:
% by mol Mols/hour -- CH4 5.10 0.16 C02 16.60 0.52 -~
-- H20 29.27 0.92 -- Hz 34.11 1.07 C0 14.93 0.47 Molar ratio of H2:C0 at reactor outlet: 2.28:1.
___mpl__3 In this experiment, the same exerimental devices as disclosed in Examples 1 and 2 were used, but catalysts were used which contained nobLe metals deposited on alumina with surface-grafted silica moieties ar,d magnesium carriers.
_a _ly_t_for__b___ir___reac_ion_z_n__( f i _ _ _ a g i abati-A commercial alumina sypplied by AKI0, having a surface area of approximately of 200 m2/g was ;~
suspended, with stirring, in a tetraethyl silicate 30 (TES) solution. The temperature was kept comprised `- -20. 2 1 1 2 5 1 9 within the range of from 80 to 900C~ Under these conditions, a trans-esterification reaction took place which is represented by equation C8~ and led to the development of ethanol in gas form~
Si(OC2Hs)4 ~ Al-OH ---> Al-O-SitOC2Hs)3 + C2Hs-OH
A gas stream of anhydrous nitrogen ~as fed to the reaction environment. Gas-chromatographic analyses on the leaving gas showed that ethanol had been formed.
The reaction was regarded as concluded when in the gas stream the presence of ethanol was no longer detectable. At this point, the temperature was increased up to 180C, in order to distil off any unreacted TES. The unreacted ethoxy groups bonded to silicon atoms which, in their turn, were anchored to the surface, were then hydrolized by feedir,g, at 2000C, a nitrogen stream saturated with steam. The so obtained solid material was heated up to 8000C and was kept at this temperature during 10 hours. After cooling, the material was used as a carrier, onto which rhodium and platinum were deposited. The finished catalyst contained 0.1X of rhodium and 0.5%
by weight of platinum.
Ca_3ly___f___t_e_s___nd___3__i_ _zQ___lse_ond_3gi3b3tic - ~. ;
l3ye_) The surface silica-grafting process as disclosed above was repeated on a carrier of commercial magnesium oxide having a surface area of 150 m2lg.
Onto this magnesium oxide with surface-grafted silica moieties obtained by means of this procedure, 0.1X by weight of Rh and 0.5% by ~eight of Ru were then , .

21. 2112~19 ~

deposited according to the same procedure as disclosed ; ~ ;
;n Example 1. `;;
The catalytic test was carried out according to -the same procedure as disclosed in Examples 1 and 2.
After a reducing treatment, a stream containing CH4:C02:02:H20 in molar ratios of 1.û:1.0:û.4:1.0 was fed to the inlet to the first catalytic bed. Before entering the second catalytic bed, the stream leaving from the first catlytic bed was admixed with an oxygen ;- -~ r 10 stream fed at a flowrate of 1.8 Nl/hour. ` - i~
The main features of this experiment are ;-disclosed in Table 3 TABLg_3 , `
___3gl3b3ti__l3yer Catalyst~
-- composition: Rh (0,1%) ~ Pt (0,5%) on silica~
grafted alumina ?~ ~--- amount: 5 cc Inlet composition: ;
~ 2û -- CH4:C02:02:H20 = 1.0:1.0:0.4:1.û tvolume ratios) ;~ Feed flowrate:
-- CH4 = 14.70 Nlthour -- C02 = 14.70 Nl/hour -- 02 = 5.90 Nl/hour 25 -- H20 = 14.70 Nl/hour ' -- total = S0.00 Nl/hour i` ` Temperatures: ~ --- inlet = 300~C
outlet 698 C ; `
II0d_adi_b__i _l_ye~

~ 22. 2112~19 ;~

Catalyst~
-- composition: Rh (0.1%) + Ru tO.5X) on silica~
grafted magnesium oxide -- amount: 3 ~c ~ .t ' Inlet composition~
-- gas product from the Ist layer + added 02 -- 02 feed flowrate: 1.47 Nl/hour ~ r~r Temperatures --- inlet = 6850C
-- outlet = 790 _om eo _1tion_at_ reactor_outl_t~
% by mol Mols/hour -- CH4 4.41 0.13 -- CO2 21 11 0.64 ~~ 02 ___ ___ -- H2 29.65 0.90 -- CO 18.01 0.55 Molar ratio of H2:CO at reactor outlet: 1.64:1. ;~
EX3-mel-e-4 In this experiment, to the first catalytic bed, a volume of S cm3 was charged of a catalyst containing ;~
0.1'~ by weight of Rh and O.SX by ~eight of Pd. The metals were deposited according to the same procedure as disclosed in Example 1, on a carrier constituted by magnesium and aluminum oxides (Mg:Al = 7:1 mol/mol), using a solution containing Rh4(C0)12 and CPd(CsHsO2)2] in a hydrocarbon solvent.
To the second catalytic bed, a volume of 4 cm3 was then charged of a catalyst containing O.SX by 23. 2~ 12~19 . . " . .~ - .. ...
weight of Ru and O.5Y by weight of Ir, deposited on magnesium and aluminum mixed oxide. The deposition of -these metals onto the carr;er ~as accomplished by ~-~
adding, dropwise, a solution of Ir4(CO)l2 and --S Ru3~CO)12 in a hydrocarbon soLvent, to a suspension of ~ ~H
the carrier in the same solvent, as discLosed in Example 1.
After a treatment in a Hz-N2 stream at 500oC, a stream of CH4 and 02 (CH4:02 = 60:25 by vol/vol) was t .
10 added to the first catalytic bed, and upstream from the second catalytic bed, a stream of CH4, 2 and C02 ~-.. `
(CH4:02 :C02 = 40:25:40 by vol/vol) was admixed to the 3 gas stream from the first catalytic bed.
The main features obtained during the catalytic 15 test are reported in Table 4.
TA@LE_4 I_ _3diaba_i__l3y__ Catalyst:
-- composition: Rh (0,1Y.) + Pt (0,5%) on MgAlOx 20 -- amount: 5 cc Inlet composition:
-- CH4:02 = 60:25 (volume ratios) Feed flowrate:
-- CH4 = 15.78 Nl/hour -- 02 = 6.60 Nl/hour -- total = 22.38 N~/hour -Temperatures:
-- inlet = 3000C
-- outlet = 745oc IIng_3d13b3t7__~3Ye_ ~ -~

24~
2 1 1 2 ~ 1 9 ~ ~

Catalyst: i~' -- composition: Ir (005%) + Ru (0.5%) on HgAlOy .
~ -- amount: 4 cc Inlet composition: ~ e ;a -- gas product from the Ist layer + CH~ + 02 + CO
added ~ , -- feed flourate:
-- CH~ = 10.52 Nl/hour .~
-- 02 = 6.50 Nl/hour ~ ~
10 -- CO2 = 10.50 Nl/hour -- total = 27.52 Nl/hour -~: R
Temperatures~
-- inlet = 581C
-- outlet = 815C
_omeositicn_at re___or outlet:
% by mol Mols/hour -- CH~ 13.95 0.43 ;~
-- CO2 14.47 0.45 -- H20 14.90 0.46 - ;~
20 -- 02 ~~~ . I---- Hz 32.40 1.01 I :: ~
-- CO 24.28 0.76 .~:~
Molar rat;o of H2:CO at reactor outlet: 1.33:1.
.
E x 3 m e l e _ 5 In this case, the procèss of catalytic partial ~
oxidation in an adiabatic reactor ~ith layer --configuration ~as studied by using three Plug-Flou reactors (uhich are referred to in the folLouing as "R1", "R2'', "R3"), each containing one catalytic bed. :~
`~

~ ~:

,.. ~,~, . . . . . .

25.
2 1 1 2 ~ 1 9 ...... ........

A m i x t u r e of CH~, 02, CO2, fed ~ith a total gas flowrate of 149 Nl/hour (CH~ :2 :C2 = 1:0.6:0.~ by vol/vol) was subdivided into three streams. The first stream (flowrate 60.1 Nl/h) was fed to the inlet to reactor R1; the second stream tflowrate 53.3 Nl/h) was fed to a point between reactor R1 and reactor R2; the third stream tflowrate 35.6 Nl/h) was fed to a point between reactor R2 and reactor R3.
The temperature of the stream fed to the inlet to the first reactor was kept at 3000C, and the inlet temperatures to the second and third reactors were kept at 4500C. The catalyst contained in reactor R1 (catalyst volume: 3 cm3) was composed by Rh (0.1% by weight) and Pd (O.S~, by weight) deposited on a support constituted by a mixed magnesium and aluminum oxide, prepared by operating according to the same procedure as disclosed in Example 1.
., .~ .
The catalyst contained in reactor R2 (catalyst volume: 4 cm3) was composed by Rh tO.1% by weight) and Ir tO~5X by weight), deposited on the same carrier of magnesium and aluminum oxides. The catalyst was prepared according to the same procedure as disclosed in Examples 1 and 3. The catalyst contained in R3 was composed by Rh tO.1'X. by weight) and Ru (0.5% by '2 ~
weight), deposited, also in this case, onto the same ~ ~-magnesium and aluminum oxide. The catalyst was prepared according to the same procedures as disclosed in Example 1.
In Table 5, the main features and the results of -. ~

26.

the present experiment are reported. ~ - A
TABLE_5 I_t_3dl3b3t1--layer Catalyst:
S -- composition: Rh (O,lY.) + Pt (0,5%) on MgAlOx -- amount: 3 cc Inlet composition:
-- CH4:02:CO2 = 100:60:80 (volume ratios) Feed flowrate:
-- CH4 = 25.10 Nl/hour -- CO2 = 20.00 Nl/hour -- 02 = 15.00 Nl/hour -- total = 60.10 Nl/hour ~-Temperatures:
-- inlet = 3000C
-- outlet = 8650C
IInd_3di3b3 i__l_Y__ Catalyst~
-- composition: Rh (O.lY.)+Ir tO.5Y.) on MgAlOx , ;~i ,r"~
; 20 -- amount: 4 cc Inlet composition: ~ ---- gas product from the Ist layer + CH~ + 02 + C02 ;~ ~
added p ~, -- feed flo~rate: ;n~
25 -- CH9 = 22.6 Nllhour ---- 02 = 17.5 Nl/hour -- CO2 = 13.2 Nl/hour -- total = 53.3 Nl/hour -r Temperatures:
,, ~ 30 -- inlet = 450 - ~ ~

~ 27.
2112519 ~ ~ ~

~- outlet = 8250C
I I I _ _ _ 3 g i 3 b 3 _ i e _ l 3 y - - '" ''' ~''~ `''' Catalyst~
~- composition: Rh (0.1X) + Ru (0.5X) on ~gAlOy ~ 2 -- amount: 5 cc Inlet composition:
-- gas product from the IInd layer + CH4 + 02 + C02` ~ ~ -added -- feed flowrate~
10 -- CH4 = 15.0 Nl/hour -- 02 = 11.9 Nl/hour -- CO2 = 8.7 Nl/hour -- total = 35.6 Nl/hour ~ ~ .;-~
Temperatures~
-- inlet = 4500C
-- outlet = 7850C
Comeosition at reactor outlet:
___ _________________________ % by mol Mols/hour .: ~ .
-- CH4 5.74 0.54 -- CO2 18.23 ~.82 -- ~20 16.89 1.59 -- 02 --- ___ - - H 2 30.33 2.87 -- CO 28.84 2.72 ~olar ratio of H2 :CO at reactor outlet: 1.055:1. `
_X_mel_____ i~
: The same experimental apparatus and the same catalysts as disclosed in Example 5 ~ere used in Examples 6, 7 and 8 in order to obtain a catalytic partial oxidation process on a three-layer catalyst, 28.
2112~19 - ~

to which a feedstock consisting of methane, C02 and oxygen was fed. In these cases, differently from the -~ -experiment as disclosed in Example 5, the whole amounts of CH4 and CO2 were fed to the inlet to the first reactor R1, and the oxygen feed ~as subdivided into three streams which were fed to the inlet o~ R1, to an intermediate point between R1 and R2, and to an intermediate point between R2 and R3. Examples 6, 7 and 8 are different from each other owing to the inlet temperatures of the gas streams to the three adiabatic layers. Different inlet temperatures to the adiabatic Layers have determined different temperatures and composition of the bed leaving streams.
In following Tables 6, 7 and 8, the main features and the results obtained in Examples 6, 7 and 8 are reported.
TABLE_6 I _ t _ 3 g i 3 b 3 _ 1 _ _ l 3 y e r Catalyst~
20 -- composition: Rh (0,1%) + Pt (û,5%) on MgAlOx ~ ~ ;
-- amount: 4 cc Inlet composition:
-- CH4:02:CO2 = 100:30:60 (volume ratios) '`
Feed flowrate:
-- CH4 = 68.30 Nl/hour -- CO2 = 41.00 Nl/hour -- 02 = 20.50 Nl/hour -- total = 129.80 Nl/hour Temperatures:
-- inlet = 3000C

~ ~ , -, ~;;

, :. . : ~ :
,, , ,~ ~

, . :
. .,-: :: . , :
;~ , . . .

29. :~
2112~9 -- outlet = 7100C
Il-ng--adi3batic layer Catalyst~
-- composition: Rh tO.1X) + Ir tO.57.) on MgAlOx -- amount: 4 cc Inlet composition~
-- gas product from the Ist layer + 02 added : --- feed flowrate:
-- Oz = 13.6 Nl/hour -- total = 13.6 Nl/hour Temperatures:
-- inlet = 4500C .
-- outlet ~ 77soc III_g_adi3batlc_layer .'; ,~ ,`.
Catalyst:
-- composition: Rh tO.1%) + Ru (0.5%) on MgAlO.y :~
-- amount: 5 cc ~
Inlet composition: ~:
-- gas product from the IInd layer + 02 added . ~.
ZO -- feed flowrate:
-- 02 = 6.8 Nl/hour !
-- total = 6.8 Nl/hour Temperatures:
, ~: , ' .;. ~: ,.
-- inlet = 4500C
-- outlet = 7780C
__meo_itjion_ati_r_a_tior_ut~
~: X by mol Mols/hour -- CH4 7.2 0.69 - - C 0 2 16.1 1.54 -- H20 16.6 1.59 :: .:

30. :: :
2112519 ` ~
:'.' :''' -- 02 ~~~ ~~~
-- H2 32.6 3.1Z
-- CO 27.6 2.64 :~
Molar ratio of H2:CO at reactor outlet: 1.1818 TABLE_7 Ist__di_bati__Lay_r Catalyst~
-- composition: Rh (0,1X) + Pt tO,5%) on MgAlOx -- amount: 4 cc .
Inlet composition~
-- CH4:02:CO2 ~ 100:30:60 ~volume ratios) Feed flowrate~
-- CH~ = 68.30 NL/hour -- CO2 = 41.ûû Nl/hour :R-~
-- Oz = 20.50 Nl/hour -- total = 129.80 Nl/hour Temperatures~
-- inlet = 3000C
-- outlet = 715C ~ :~
IInd__di_b_ti__l_ye_ Catalyst:
-- composition: Rh (0.1%) + Ir tO.5%) on MgAlOx -- amount: 4 cc Inlet composition: : :~
25 -- gas product from the Ist layer + 02 added :
-- feed flo~rate--- 02 = 13.6 Nl/hour ~: -- total = 13.6 Nl/hour ;~ ~ -Temperatures~
~: 30 -- inlet = 5500C ~:

: - . :.
~ , 31' 2 II2~ I9 -- outlet = 7970C
IIIrd_3di_batic_l_y r Catalyst: :
-- composition: Rh tO.1%) + Ru (0.5X) on MgAlOy -- amount: 5 cc Inlet composition~
-- gas product from the IInd layer + 02 added -- feed flowrate:
-- Oz = 6.8 Nl/hour -- total = 6.8 Nl/hour Temperatures~
-- inlet = 5500C
-- outlet = 816C
COmQOsi tion_at_re__tor_outl_t: .. ~ ~ .
% by mol Mols/hour -- CH~ 4.6 0.46 ~- --- CO2 16.1 1.34 -- H20 15.6 1.56 ~- 02 --- ___ 20 -- H2 35.9 3.60 -- CO 30.6 3.07 Molar rat;o of Hz:CO at reactor outlet: 1.172:1.
TABLE_8 .
Ist-3di3b3-l--l3y--r '' 25 Catalyst:
-- composition: Rh (0,1%) + Pt ~0,5%) on MgAlOx ~ `
-- amount: 4 cc Inlet composition~
-- CH4:02:CO2 = 100:30:60 (volume ratios) 30 Feed flrJwrate: ~

: '- :,: :

2 1 1 2 ~ ~ 9 -- CH4 = 68.30 Nl/hour ~. :
-- CO2 = 41.00 Nl/hour ~~ 02 = 20 . 50 Nl/hour -- total = 129.80 Nl/hour Temperatures~
-- inlet = 4000C
-- outlet = 7220C
ng_3glabat1~ y~
Catalyst:
- composition: Rh (0.1%) + Ir (0.5X) on MgALOx -- amount: 4 cc Inlet composition: .-~:.` r~x -- gas product from the Ist layer 02 added -- feed flo~rate:
15 -- 2 = 13.6 Nl/hour : -- total = 13.6 Nl/hour Temperatures:
-- inlet = 6000C
-- outlet = 812C :-2û IlIrg-3gl3b3-~ ay-- -~
Catalyst: ; ::
-- composition: Rh (0.1~) + Ru (0.5%) on MgAlOx -- amount: S cc Inlet composition:
25 -- gas product from the IInd layer + 02 added :
;~ -- feed flowrate:
~~ 2 = 6.8 Nl/hour -- total = 6.8 Nl/hour Temperatures~
30 -- inlet = 6000C

' ~:.'' .

33. 2112519 ~:

, ~.~ ., -- outlet = 841C -~
__meositiQn at eactor__utl_t~
% by mol ~oLs/hour -- CH4 3.3 0.34 ;~--- C02 11.9 1.Z2 `~ --- H2O 15.1 1.55 -- Hz 37.6 3.87 -- C0 32.2 3.31 Molar ratio of H2:C0 at reactor outlet: 1.169:1. `~
__am e Le_9 The same experimental apparatus as disclosed in Examples 5-8 was used in order to study the reactions of catalytic partial oxidation of mixtures of `',,',`',~
CH4 :2 :C02 = 100:60:30 (by vol/vol). In this case, the content of C02 was kept at lower values than as in the preceding examples. Also in this case, the oxygen stream was subdivided into partial streams which were ~ `
~ . .:
fed both to the inlet to R1, and to an intermediate ~
20 point between R1 and R2, as well as to an intermediate ~ 2 point between R2 and R3. Furthermore tby pre-heating ` ~ `
the gas reactant streams), inlet temperatures to the catalytic beds were tested which were higher than in ~ -the preceding examples. The catalyst used in reactor 25 R1 (Ist adiabatic layer) contained Rh (O.lX by weight) and Pt (0.5X by weight) deposited on a mixed aluminum and magnesium oxide. The preparation procedures used have already been disclosed in the preceding examples. ~ `"Y;i `~
The catalysts contained in the second reactor 0 tR2) an~ in the third reactor tR3) ti.e., the second 34 2112519 ~

and third ad;abatic layers) ~ere the sa~e as used in Examples 5-8 and contained Rh and, respectively, Ir, deposited on an aluminum and magnesium oxide, and Rh and Ru deposited on the same support. ~-S In follo~ing Table 9, the ma;n features of the experiment are reported _BLE 9 st_adi_ba_ic_layer Catalyst -- composition: Rh (0,1X) + Pt (0,5%) on MgAlOx -- amount: 4 cc `~
Inlet composition~
-- CH4:02:CO2 = 100 30 30 (volume ratios) Feed flowrate:
15 -- CH~ = 79.00 Nl~hour -~
-- COz = 23 70 Nl/hour ;~
- - 2 = 23.70 Nl/hour -- total = 126.40 Nl/hour ; -Temperatures `~
20 -- inlet = 4000C
-- outlet = 7610C
I I n d _ _ d i _ b 3 _ i c _ l _ y _ _ Catalyst --- composition: Rh (0.1%) + Ir (0.5%) on MgAlOx 25 -- amount: 4 cc ~ 9-~
Inlet composition~
-- gas product from the Ist layer 02 added -- feed flowrate:
- - 2 = 15.8 Nlthour -- total = 15.8 Nl/hour ~ '. ' `,`.,`~-' ` :- 35. 2112519 Temperatures~
-- inlet = 6000C ,;;~
-- outLet ~ 8530C '~
IIIrd 3diabatic layer ',~
S Catalyst:
-- composition: Rh (0.1%) + Ru (0.5%) on MgAlO~ ~;,;,~''' -- amount: 5 cc '~
Inlet composition:
-- gas product 'from the'`I'Ind lay'er + 02 added ~,'~
-- feed flowrate:
-- 02 = 7.9 Nl/hour ~'~'s`' -- total = 7.9 Nl/hour ..`' .' :~'..'. '. ':
Temperatures: '~
~ -- inlet = 6000C ,'6,~
¦ 15 -- outlet = 841C
__m eo i tion_at_reactor__ytle_~
% by mol Mols/hour -- CH4 3.1 0.34 -- C02 6.9 0.76 ~'~','''~
20 -- H20 12.3 1.34 '~
~- 02 --- ----- H2 45,9 5 03 :~---- C0 31.8 3.48 Molar ratio of H2:C0 at reactor outlet: 1.445:1.
' 25 i , .

;'~
. , . ,, ;~,.

: .:., ~

Claims (15)

1. Catalytic process for preparing synthesis gas by starting from methane, oxygen and, possibly carbon dioxide and water, characterized in that:
-- the catalyst used is a noble metal catalyst supported on a solid carrier, arranged as a plurality of fixed catalytic beds in cascade to each other;
-- the gas feed stream contains methane, oxygen, carbon dioxide and water in the following molar proportions methane 1 0;
oxygen from 0 2 to 1 0;
carbon dioxide from 0 to 3.0;
water from 0 to 3 0; and -- the process is carried out under adiabatic conditions;
by feeding the gas reactant stream upstream from the first catalytic bed and removing heat, by heat exchange between the catalytic beds arranged in cascade, or by feeding the gas reactant stream partially upstream from the first catalytic bed and partially, as a cold stream, between the catalytic beds arranged in cascade, with said partial feeds being of same composition, or having different compositions from each other, with the proviso that methane is at least partially fed to the first catalytic bed and oxygen is subdivided between all of the catalytic beds.
2. Process according to claim 1, characterized in 37.
that in the gas feed stream the reactants are contained in the following proportions, by mol:
methane 1.0; oxygen 0.4-0 6; carbon dioxide 0-1.0; and water, 0-1Ø
3. Process according to claim 1, characterized in that the catalysts are constituted by one or more metals from platinum group, selected from Rh, Ru, Ir, Pt and Pd, supported on a carrier selected from aluminum, magnesium, zirconium, silicon, cerium and/or lanthanum oxides and/or spinels, or on the silica-treated grades of such carriers
4. Process according to claim 3, characterized in that the catalysts of the first catalytic bed contain rhodium in association with platinum or palladium, and the catalyst of the subsequent catalytic beds contain two metals selected from rhodium, ruthenium and iridium, with the overall percent content of noble metals in the supported catalyst being comprised within the range of from 0.05 to 1.5% by weight, and preferably of from 0.1 to 1% by weight.
5. Process according to claim 1, characterized in that said catalysts are in granular form with particle size comprised within the range of from 1 to 20 mm and are arranged in at least 2 and up to 5 catalytic beds, and preferably either 2 or 3 catalytic beds.
6. Process according to claim 1, characterized in that to the first catalytic bed a gas stream is fed which contains methane, oxygen, carbon dioxide and steam, and to the subsequent catalytic beds an oxygen stream is fed.

38.
7. Process according to claim 6, characterized in that the process will be carried out with a molar ratio of methane, carbon dioxide and water fed to the first catalytic bed, of 1:0.5-1:0.3-1, and with a total oxygen amount of 0.4-0.6 mols per each methane mol, subdivided to the several catalytic beds.
8. Process according to claim 1, characterized in that to the first catalytic bed a gas stream is fed which contains methane and oxygen, and to the subsequent catalytic beds a mixture is fed which contains methane, oxygen and carbon dioxide.
9. Process according to claim 8, characterized in that the process is carried out with a molar ratio of methane to oxygen fed to the catalytic beds of the order of 1:0.4, and with an amount of carbon dioxide of the order of 0.4 mols per each mol of methane.
10. Process according to claim 1, characterized in that to the first catalytic bed and to the subsequent beds, a gas stream is fed which contains methane, oxygen and carbon dioxide.
11. Process according to claim 10, characterized in that the process is carried out with molar ratios of these reactants to each other of the order of 1:0.6:0.7-0.8.
12. Process according to claim 1, characterized in that to the first catalytic bed a gas stream is fed which contains methane, oxygen and carbon dioxide and to the subsequent catalytic beds an oxygen stream is fed.
13. Process according to claim 12, characterized 39.
in that the process is carried out with a molar ratio of methane to carbon dioxide fed to the first catalytic bed of 1:0.3-0.6, and with a total oxygen amount of 0.5-0.6 mol per each methane mol, subdivided to the various catalytic beds.
14. Process according to claim 1, characterized in that the process is carried out with inlet temperatures to the first bed of the order of 300-400°C and with outlet temperatures from said first bed of the order of 700-870°C, with inlet temperatures to the beds downstream from the first bed, of the order of 450-730°C, and outlet temperatures of the order of 770-850°C, with the cooling between two adjacent beds causing a temperature decrease of from at least 10°C, up to 420°C, and normally of the order of 120-170°C.
15. Process according to claim 1, characterized in that the process is carried out under pressures of from 0.1 to 10 MPa and with space velocity values, under the reaction conditions, comprised within the range of from 1,000 to 50,000 h-1 and preferably of the order fo 5,000-20,000 h-1.
CA002112519A 1992-12-23 1993-12-22 Catalytic process for producing synthesis gas Abandoned CA2112519A1 (en)

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ITMI922938A0 (en) 1992-12-23
NO934736D0 (en) 1993-12-21
IT1256227B (en) 1995-11-29
GB2274284B (en) 1996-08-07
DZ1739A1 (en) 2002-02-17
NO934736L (en) 1994-06-24
ITMI922938A1 (en) 1994-06-23
GB2274284A (en) 1994-07-20
GB9326099D0 (en) 1994-02-23

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