A PROCESS FOR PREPARING A MOLDING, A MOLDING AND USE THEREOF AS METHANE REFORMING CATALYST

Abstract

The present invention relates to a process for preparing a molding comprising a mixed oxide comprising O, Mg, and Ni, the process comprising: —(i) mixing water, a Mg source, a Ni source, and an acid, to obtain a mixture; —(ii) subjecting the mixture obtained from (i) to a shaping process; —(iii) calcining the molding obtained from (ii) in a gas atmosphere having a temperature in the range of from 700 to 1400° C.; wherein the molar ratio of the acid used in (i) to Ni, calculated as elemental Ni, of the Ni source used in (i), acid:Ni, is equal to or higher than 0.001:1. Further, the present invention relates to a molding comprising a mixed oxide comprising O, Mg, and Ni, wherein the mixed oxide comprises a specific crystalline phase Ni.sub.xMg.sub.yO, wherein the sum of x and y is 1, and wherein y is greater than 0.52. The molding is used for reforming methane to a synthesis gas comprising hydrogen and carbon monoxide.

Claims

1.-15. (canceled)

16. A process for preparing a molding comprising a mixed oxide comprising O, Mg, and Ni, the process comprising (i) mixing water, a Mg source, a Ni source, and an acid, to obtain a mixture; (ii) subjecting the mixture obtained from (i) to a shaping process, obtaining a molding comprising the mixed oxide; (iii) calcining the molding obtained from (ii) in a gas atmosphere having a temperature in the range of from 700 to 1400° C.; wherein the molar ratio of the acid used in (i) to Ni, calculated as elemental Ni, of the Ni source used in (i), acid:Ni, is equal to or higher than 0.001:1.

17. The process of claim 16, wherein the weight ratio of Ni, calculated as elemental Ni, of the Ni source used in (i), relative to Mg, calculated as elemental Mg, of the Mg source used in (i), Ni:Mg, is in the range of from 0.1:1 to 5:1.

18. The process of claim 16, wherein the Mg source comprises one or more of magnesium carbonate, magnesium chloride, magnesium citrate, magnesium hydroxide, magnesium oxide, hydrotalcite and aluminum magnesium hydroxy carbonate.

19. The process of claim 16, wherein the Ni source comprises one or more of elemental nickel, nickel carbonate, nickel nitrate, nickel formate, nickel acetate, nickel chloride, nickel hydroxide, nickel nitrite, and nickel oxide.

20. The process of claim 16, wherein the weight ratio of the sum of the weight of the Mg source used in (i) and the weight of the Ni source used in (i) to the sum of the weight of the acid used in (i) and the weight of the water used in (i), is in the range of from 0.1:1 to 1:0.1.

21. The process of claim 16, wherein in (i) a source of a metal M is further admixed, wherein M is selected from the group consisting of aluminum, gallium, indium, silicon, germanium, tin, titanium and zirconium.

22. The process of claim 16, wherein the acid used in (i) comprises one or more of an organic acid and an inorganic acid.

23. A molding comprising a mixed oxide comprising O, Mg, and Ni, obtained by the process according to claim 16.

24. A molding comprising a mixed oxide obtained by the process according to claim 16, wherein the mixed oxide comprises O, Mg, and Ni, wherein the mixed oxide comprises a crystalline phase Ni.sub.xMg.sub.yO, wherein the sum of x and y is 1, and wherein y is greater than 0.52.

25. The molding of claim 24, wherein the mixed oxide further comprises a crystalline phase Ni.sub.aMg.sub.bO, wherein the sum of a and b is 1, and wherein a is equal or greater than 0.70, wherein x is not equal to a.

26. The molding of claim 24, wherein in the mixed oxide the molar ratio of nickel to magnesium, Ni:Mg, each calculated as elemental Ni and Mg respectively, is in the range of from 0.20:1 to 0.75:1.

27. A process for preparing a re-shaped molding, wherein the process comprises (a) optionally calcining the molding obtained from (iii) of a process according to claim 16, in a gas atmosphere having a temperature in the range of from 350 to 550° C.; (b) optionally crushing the molding obtained from (a) to particles having an average particle size in the range of from 0.1 to 0.9 mm, determined according to Reference Example 2; (c) optionally preparing a mixture comprising one or more binders and the molding obtained from (b); (d) subjecting a molding obtained from (iii) of a process according to claim 16, to a re-shaping process; (e) calcining the molding obtained from (d) in a gas atmosphere having a temperature in the range of from 800 to 1300° C., obtaining a re-shaped molding.

28. A re-shaped molding comprising a mixed oxide comprising O, Mg, and Ni, obtained by the process of claim 27.

29. Use of a molding according to claim 23 as a catalytically active material, as a catalyst component or as a catalyst.

30. A method for reforming one or more hydrocarbons to a synthesis gas comprising hydrogen and carbon monoxide, the method comprising (a) providing a reactor comprising a reaction zone which comprises the molding of claim 23; (b) passing a reactant gas stream into the reaction zone obtained from (a), wherein the reactant gas stream passed into the reaction zone comprises the one or more hydrocarbons, carbon dioxide, and water; subjecting said reactant gas stream to reforming conditions in said reaction zone; and removing a product stream from said reaction zone, said product stream comprising hydrogen and carbon monoxide.

Description

EXAMPLES

Reference Example 1: Determination of the BET Specific Surface Area and the Langmuir Specific Surface Area

[0252] The BET specific surface area and the Langmuir specific surface area were determined via nitrogen physisorption at 77 K according to the method disclosed in DIN 66131.

Reference Example 2: Determination of Crystallinity Via XRD

[0253] The sample is ground using a mill until it is a fine powder. The mill used is a “Tube Mill” manufactured by IKA-Werke GmbH & CO. KG. After that the samples are transferred to a standard sample holder (material PMMA, manufacturer Bruker AXS) and flattened using a glass plate. The samples are measured in a D8 Advance diffractometer (Bruker AXS) using variable slits set to a constant angle of 0.3° and an area detector (LYNXEYE, Bruker AXS) in an angular range of 10°-80° 2theta with a step size of 0.02° 2theta.

[0254] The data analysis is performed using the software TOPAS 6 (see TOPAS Users Manual of Nov. 22, 2017). The modelled phase composition is set to: MgAl.sub.2O.sub.4 and MgO:Ni. The structure published in Acta Crystallographica (see Acta Crystallographica 1952, 5, 684-686) was used to model the MgAl.sub.2O.sub.4 Spinell. The structure published in Zeitschrift für Kristallograhie—Crystalline Materials (see Z. Kristallogr. 1921, 56, 430) was used as a basis for the model of MgO:Ni. The occupation of the Ni doping was refined by using Vegard's law (see Zeitschrift für Physik 1921, 5, 1, 17-26; doi:10.1007/BF01349680) of the linear correlation between the mixed elemental occupation of crystallographic site with the lattice parameters. It was determined that the occupation of Ni takes the following value in dependance on the lattice parameter (a) of MgO:Ni

Nickel occupation=(4.2122 Angstrom−α)/0.0343

[0255] In all phases the lattice parameters are refined. The crystallite size is refined assuming a lorenzian profile contribution, in addition the Gaussian strain component is refined for phase MgO:Ni. The background is modelled using a 2nd order Polynomial. Sample height is also refined. Intensity corrections for Lorentz and polarization effects are considered. The reported crystallite size is that given out by TOPAS in the field “Lvol FWHM”.

Reference Example 3: Determination of Temperature Programmed Reduction (TPR) Profile

[0256] The reduction behavior of a molding was determined by temperature programmed reduction. 200 mg of a sample having particles with an average particle size between 0.2 and 0.4 mm were used. As a feed gas a stream of 5 volume-% hydrogen in Argon was used, whereby the feed rate was set to 50 ml/min. The temperature was increased during a measurement from room temperature up to 950° C. with a heating rate of 5 K/min. The thermal conductivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. The TPR profiles of Examples 1-6, and Comparative Examples 1 are shown in FIGS. 2 and 3. The maxima in the recorded data related to the hydrogen consumption of a sample indicating reduction of Nickel.

Example 1: Preparation of a Molding Comprising a Mg-Rich Crystalline Phase Ni.SUB.x.Mg.SUB.y.O

[0257] 200 g of an aluminum magnesium hydroxyl carbonate (Mg.sub.2xAl.sub.2(OH).sub.4x+4CO.sub.3.n H.sub.2O; Pural MG30; Sasol; lot number 11115) and 52.7 g nickel(II)carbonate (CAS 12607-70-4; containing 47.8 weight-% of Ni; Sigma-Aldrich) were mixed for several minutes in a kneader (alternatively in a mixer). Then 200 ml of an aqueous solution of formic acid in deionized water (50 weight-% of formic acid in water, the aqueous solution having a density of 1.1207 kg/I at 20° C.) and 50 ml of deionized water were added within 10 min. Under further mixing during 10 min a dough-like homogeneous mass was formed. The obtained mass was then extruded to strands with 3.5 mm in diameter. Then, the extrudates were dried at 120° C. for 16 hours. Subsequently, the dried extrudates were calcined in an annealing furnace under air at 950° C. for 4 hours.

[0258] The nickel content of the calcined moldings was 15.3 weight-%, the magnesium content 13.1 weight-% and the aluminum content 29.1 weight-%, calculated as the elements, respectively. The calcined moldings comprised 81 weight-% of a crystalline phase MgAl.sub.2O.sub.4 having an average particle size of 12 nm and 19 weight-% of a crystalline phase Ni.sub.xMg.sub.yO, whereby x was 0.34 and y was 0.66, having an average particle size of 15 nm. The lattice parameter a of the Ni.sub.xMg.sub.yO phase was determined as being 4.1997. In the TPR profile, a first peak was found having a maximum at about 775° C. and a second peak having a maximum at about 875° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 69 micromol H.sub.2/g product, and above 600° C. of 2141 micromol H.sub.2/g product.

Example 2: Preparation of a Molding Comprising a Mg-Rich Crystalline Phase Ni.SUB.x.Mg.SUB.y.O

[0259] In accordance with Example 1 a molding was prepared, whereby a different nickel source was used. Nickel(II)carbonate as the nickel source was prepared by precipitating nickel(II)carbonate from a nickel nitrate solution. In particular, 1000 g of deionized water were placed in a 10 l beaker and heated to a temperature of 80° C. 2274 g of an aqueous nickel nitrate solution (13.2 weight-% nickel content, density of 1.514 kg/I) was provided separately and heated up to a temperature of 80° C. Further, 3776.5 g of an aqueous sodium carbonate solution (20 weight-% Na.sub.2CO.sub.3 in water) was provided separately and heated up to a temperature of 80° C. The aqueous nickel nitrate solution and the aqueous sodium carbonate solution were added to the deionized water in the beaker, whereby the pH was kept between 7 and 8. The resulting solids were filtered off and washed with about 169 l deionized water. The resulting solids were dried at 105 h for 16 h to yield 572 g of nickel carbonate.

[0260] The nickel content of the calcined moldings was 16.3 weight-%, the magnesium content 12.8 weight-% and the aluminum content 28.1 weight-%, calculated as the elements, respectively. The calcined moldings comprised 74 weight-% of a crystalline phase MgAl.sub.2O.sub.4 having an average particle size of 9 nm and 26 weight-% of a crystalline phase Ni.sub.xMg.sub.yO, whereby x was 0.46 and y was 0.54 having an average particle size of 21.5 nm. The lattice parameter a of the Ni.sub.xMg.sub.yO phase was determined as being 4.1954. In the TPR profile, a first peak was found having a maximum at about 800° C., a second peak having a maximum at about 860° C., and a third peak having a maximum at about 450° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 144 micromol H.sub.2/g product, and above 600° C. of 2565 micromol H.sub.2/g product.

Example 3: Preparation of a Molding Comprising a Mg-Rich Crystalline Phase Ni.SUB.x.Mg.SUB.y.O

[0261] In accordance with Example 1 a molding was prepared, whereby a different acid was used. As an acid nitric acid was used instead of formic acid, whereby an amount of nitric acid was used in Example 3 such that the molar ratio of acid used to Ni, calculated as elemental Ni, was 0.6:1. Further, the nickel source was first mixed with the acid and water, and subsequently mixed with the aluminum magnesium hydroxyl carbonate.

[0262] The nickel content of the calcined moldings was 15.1 weight-%, the magnesium content 12.7 weight-% and the aluminum content 28.7 weight-%, calculated as the elements, respectively. The calcined moldings comprised 73 weight-% of a crystalline phase MgAl.sub.2O.sub.4 having an average particle size of 8 nm, 8 weight-% of a crystalline phase Ni.sub.aMg.sub.bO, whereby a was 0.78 and b was 0.22, having an average particle size of 44 nm and 19 weight-% of a crystalline phase Ni.sub.xMg.sub.yO, whereby x was 0.46 and y was 0.54, having an average particle size of 3.5 nm. The lattice parameter a of the crystalline phase Ni.sub.aMg.sub.bO was determined as being 4.1844, and the lattice parameter a of the crystalline phase Ni.sub.xMg.sub.yO was determined as being 4.1956. In the TPR profile, a first peak was found having a maximum at about 775° C., a second peak having a maximum at about 875° C., and a third peak having a maximum at about 500° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 634 micromol H.sub.2/g product, and above 600° C. of 1710 micromol H.sub.2/g product.

Example 4: Preparation of a Molding Comprising a Mg-Rich Crystalline Phase Ni.SUB.x.Mg.SUB.y.O

[0263] In accordance with Example 1 a molding was prepared, whereby a different acid and a different nickel source was used. As an acid nitric acid was used instead of formic acid, whereby an amount of nitric acid was used in Example 4 such that the molar ratio of acid to Ni was 0.004:1. Further, a portion of the nickel(II)carbonate as used in Example 1 was replaced by an aqueous nickel nitrate solution having a nickel concentration of 13.2 weight-% such that 70 weight-% of the nickel source was in the form of nickel(II)carbonate and 30 weight-% of the nickel source was nickel nitrate. Further, the nickel nitrate solution was first mixed with the acid, and subsequently mixed with the aluminum magnesium hydroxyl carbonate.

[0264] The nickel content of the calcined moldings was 15.2 weight-%, the magnesium content 12.9 weight-% and the aluminum content 28.7 weight-%, calculated as the elements, respectively. The calcined moldings comprised 74 weight-% of a crystalline phase MgAl.sub.2O.sub.4 having an average particle size of 8.5 nm, 5 weight-% of a crystalline phase Ni.sub.aMg.sub.bO, whereby a was 0.81 and b was 0.19, having an average particle size of 62 nm and 21 weight-% of a crystalline phase Ni.sub.xMg.sub.yO, whereby x was 0.41 and y was 0.59, having an average particle size of 4.5 nm. The lattice parameter a of the crystalline phase Ni.sub.aMg.sub.bO was determined as being 4.1835, and the lattice parameter a of the crystalline phase Ni.sub.xMg.sub.yO was determined as being 4.1972. In the TPR profile, a first peak was found having a maximum at about 800° C., a second peak having a maximum at about 875° C., and a third peak having a maximum at about 475° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 411 micromol H.sub.2/g product, and above 600° C. of 1916 micromol H.sub.2/g product.

Example 5: Preparation of a Molding Comprising a Mg-Rich Crystalline Phase Ni.SUB.x.Mg.SUB.y.O

[0265] In accordance with Example 1 a molding was prepared, whereby a different acid and a different nickel source was used. As an acid nitric acid was used instead of formic acid, whereby an amount of nitric acid was used in Example 4 such that the molar ratio of acid to Ni was 0.007:1. Further, a portion of the nickel(II)carbonate as used in Example 1 was replaced by an aqueous nickel nitrate solution having a nickel concentration of 13.2 weight-% such that 50 weight-% of the nickel source was in the form of nickel(II)carbonate and 50 weight-% of the nickel source was nickel nitrate. Further, the nickel nitrate solution was first mixed with the acid, and subsequently mixed with the aluminum magnesium hydroxyl carbonate.

[0266] In the TPR profile, a first peak was found having a maximum at about 775° C., a second peak having a maximum at about 875° C., and a third peak having a maximum at about 350° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 302 micromol H.sub.2/g product, and above 600° C. of 1713 micromol H.sub.2/g product.

Example 6: Preparation of a Molding Comprising a Mg-Rich Crystalline Phase Ni.SUB.x.Mg.SUB.y.O

[0267] In accordance with Example 1 a molding was prepared, whereby a different acid and a different nickel source was used. As an acid nitric acid was used instead of formic acid, whereby an amount of nitric acid was used in Example 4 such that the molar ratio of acid to Ni was 0.01:1. Further, a portion of the nickel(II)carbonate as used in Example 1 was replaced by an aqueous nickel nitrate solution having a nickel concentration of 13.2 weight-% such that 30 weight-% of the nickel source was in the form of nickel(II)carbonate and 70 weight-% of the nickel source was nickel nitrate. Further, the nickel nitrate solution was first mixed with the acid, and subsequently mixed with the aluminum magnesium hydroxyl carbonate.

[0268] In the TPR profile, a first peak was found having a maximum at about 750° C., a second peak having a maximum at about 875° C., and a third peak having a maximum at about 350° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 152 micromol H.sub.2/g product, and above 600° C. of 1869 micromol H.sub.2/g product.

Comparative Example 1: Preparation of a Molding According to the Prior Art

[0269] Example E1 of WO 2013/068905 A1 was repeated.

[0270] The nickel content of the calcined moldings was 14.7 weight-%, the magnesium content 14.2 weight-% and the aluminum content 30.0 weight-%, calculated as the elements, respectively.

[0271] The calcined moldings comprised 79 weight-% of a crystalline phase MgAl.sub.2O.sub.4 having an average particle size of 8 nm and 21 weight-% of a crystalline phase Ni.sub.aMg.sub.bO, whereby a was 0.52 and b was 0.48, having an average particle size of 5.5 nm. The lattice parameter a of the crystalline phase Ni.sub.aMg.sub.bO was determined as being 4.1933. In the TPR profile, a single peak was found having a maximum at about 775° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 0 micromol H.sub.2/g catalyst, and above 600° C. of 2018 micromol H.sub.2/g catalyst.

Comparative Example 2: Preparation of a Molding without Use of an Acid

[0272] In accordance with Example 1 a molding was prepared, whereby no acid was used. The respective amount of formic acid used in Example 1 was thus replaced by an equivalent mass of deionized water.

[0273] The nickel content of the calcined moldings was 15.0 weight-%, the magnesium content 12.8 weight-% and the aluminum content 28.9 weight-%, calculated as the elements, respectively. The calcined moldings comprised 75 weight-% of a crystalline phase MgAl.sub.2O.sub.4 having an average particle size of 8 nm, 7 weight-% of a crystalline phase Ni.sub.aMg.sub.bO, whereby a was 0.91 and b was 0.09, having an average particle size of 101 nm and 18 weight-% of a crystalline phase Ni.sub.xMg.sub.yO, whereby x was 0.56 and y was 0.44, having an average particle size of 12 nm. The lattice parameter a of the crystalline phase Ni.sub.aMg.sub.bO was determined as being 4.1810, and the lattice parameter a of the crystalline phase Ni.sub.xMg.sub.yO was determined as being 4.1983. In the TPR profile, a first peak was found having a maximum at about 775° C., a second peak having a maximum at about 375° C. and a third peak having a maximum at about 450° C. Further, the resulting product showed a total hydrogen consumption in the TPR profile below 600° C. of 1080 micromol H.sub.2/g product, and above 600° C. of 1271 micromol H.sub.2/g product.

Example 7: Catalytic Testing

[0274] Catalytic tests were performed on a single reactor test unit. This unit allowed for test conditions in a broad temperature and pressure regime up to 1100° C. and 20 bar (gauge). As gas feeds carbon dioxide (also designated as carbon dioxide-in or CO.sub.2-in), methane (also designated as methane-in or CH.sub.4-in), hydrogen (also designated as hydrogen-in), nitrogen (also designated as nitrogen-in) and argon (also designated as argon-in) were provided and online controlled by mass flow controllers (M FCs). Water was added as steam to the feed stream by an evaporator connected to a water reservoir. Analysis of the product gas composition was carried out by online-gas chromatography using argon as internal standard. Gas chromatographic analytics allowed the quantification of hydrogen, carbon monoxide, carbon dioxide (also designated as CO.sub.2-out), methane (also designated as CH.sub.4-out) and C.sub.2 components. Duration of the gas chromatographic method was set to 24 min. For the catalytic test, the prepared molding was split (0.5 to 1.0 mm) and 15 ml of the split were then tested as a catalyst. The sample was placed in the isothermal zone of the reactor using a ceramic fitting. Prior to the start of the experiment the back pressure was determined. The catalyst was tested according to a standard test protocol according to Table 3.

TABLE-US-00001 TABLE 3 Test protocol used for catalytic testing. In each phase the pressure was adjusted to 20 bar (gauge) Equilibrium Equilibrium Methane- CO.sub.2-in Steam- Nitrogen- for CH.sub.4- for CO.sub.2- Phase T GHSV in [mol. - in in conversion conversion [#] [° C.] [h.sup.−1] [mol.-%] %] [mol.-%] [mol.-%] [mol-%] [mol-%] 1.1 900 8000 47.5 0 47.5 5.0 63 — 2.1 900 8000 27.5 27.5 40.0 5.0 88 48 3 900 8000 38.0 19.0 38.0 5.0 76 56 4 950 4000 47.5 0 47.5 5.0 84 — 5 950 8000 47.5 0 47.50 5.0 84 — 6 950 8000 27.5 27.5 40.0 5.0 94 53 7 950 8000 38.0 19.0 38.0 5.0 85 65 1.2 900 8000 47.5 0 47.5 5.0 63 — 2.2 900 8000 27.5 27.5 40.0 5.0 88 48 GHSV: gas hourly space velocity

[0275] Based on the quantification of the product gas stream the methane conversion [1], carbon dioxide conversion [2], hydrogen/carbon monoxide ratio as well as the product gas composition and C.sub.2-components fraction were calculated:

Methane conversion: X(CH.sub.4)=1-(CH.sub.4-out/CH.sub.4-in)  [1]

Carbon dioxide conversion: X(CO.sub.2)=1-(CO.sub.2-out/CO.sub.2-in)  [2]

[0276] In addition, the relative conversions of methane [3] and carbon dioxide [4] were calculated and represent the conversions related to the thermodynamic maximum conversions X_max (equilibrium composition). The equilibrium composition was calculated taking the test conditions accordingly into account:

Methane-relative conversion: X_rel(CH.sub.4)═X(CH.sub.4)/X_max(CH.sub.4)  [3]

Carbon dioxide-relative conversion: X_rel(CO.sub.2)═X(CO.sub.2)/X_max(CO.sub.2)  [4]

[0277] In order to determine the catalytic performance of the testes samples, for each sample the deviation from equilibrium for CH.sub.4-conversion ΔX(CH.sub.4) was determined as well as the deviation from equilibrium for CO.sub.2-conversion ΔX(CO.sub.2). Based on said results, total deviation was determined as the sum of the deviation from the equilibrium for the CH.sub.4-conversion and the deviation from the equilibrium for the CO.sub.2-conversion. The results are shown in tables 4 to 6 below. The deviation from equilibrium for CH.sub.4-conversion ΔX(CH.sub.4) was calculated according to [5] and the deviation from equilibrium for CO.sub.2-conversion ΔX(CO.sub.2) was calculated according to [6]:

ΔX(CH.sub.4)═X(CH.sub.4).sup.eq-X(CH.sub.4).sup.exp  [5]

ΔX(CO.sub.2)═X(CO.sub.2).sup.eq—X(CO.sub.2).sup.exp  [6]

[0278] The total deviation was calculated according to [7]:

Σ(ΔX)=|ΔX(CH.sub.4)|+|ΔX(CO.sub.2)|

TABLE-US-00002 TABLE 4 Deviation from equilibrium for CH.sub.4-conversion ΔX(CH.sub.4) in vol-% Test phase Sample 1.1 2.1 3 4 5 6 7 1.2 2.2 Sum Example 1 1 1 2 0.7 15 5 3 4 4 35 Example 2 8 1 3 11 13 3 2 2 2 45 Example 3 8 0 1 11 12 3 1 1 1 38 Example 4 7 −1 0 8 10 4 1 0 18 48 Comp. Example 1 20 5 11 12 13 0 1 11 0 74 Comp. Example 2 8 3 5 15 19 2 5 7 3 68

TABLE-US-00003 TABLE 5 Deviation from equilibrium for CO.sub.2-conversion ΔX(CO.sub.2) in vol-% Test phase Sample 1.1 2.1 3 4 5 6 7 1.2 2.2 Sum Example 1 — −15 −20 0 0 −24 −22 0 −16 −96 Example 2 — −12 −16 0 0 −13 −14 0 −12 −67 Example 3 — −10 −14 0 0 −11 −13 0 −11 −58 Example 4 — −14 −19 0 0 −20 −15 0 −20 −88 Comp. Example 1 — −36 −52 0 0 −19 −28 0 0 −135 Comp. Example 2 — −9 −14 0 0 −9 −2 0 −10 −65

TABLE-US-00004 TABLE 6 Total deviation from combined equilibrium for CH.sub.4-conversion and equilibrium for CO.sub.2-conversion, packed density of sample in test reactor and average carbon content of spent sample Packed density Total deviation Average of sample in Time on from combined carbon content test reactor stream equilibrium of spent sample Sample [g/ml] [h] Σ (ΔX) [weight-%] Example 1 0.71 240 153 0.2 Example 2 0.65 222 112 0.38 Example 3 0.57 232 97 0.06 Example 4 0.58 230 136 0.09 Comp. 0.84 220 209 0.15 Example 1 Comp. 0.47 257 133 0.83 Example 2

TABLE-US-00005 TABLE 7 Duration in h of the test phases for the Examples and Comparative Examples Test phase Sample 1.1 2.1 3 4 5 6 7 1.2 2.2 Sum Example 1 18 12 18 70 26 24 24 24 24 240 Example 2 22 24 24 47 22 25 23 23 12 222 Example 3 18 24 24 71 6 17 24 24 24 232 Example 4 24 22 24 49 22 24 21 20 24 230 Comp. Example 1 20 12 20 65 7 23 25 24 24 220 Comp. Example 2 23 22 23 69 24 24 27 24 21 257

[0279] In Example 1, the test phase 4 was conducted after test phase 7, such that the test sequence was 1.1, 1.2, 3, 5, 6, 7, 4, 1.2, 2.2.

[0280] As can be seen from the results shown in table 4 relative to the CH.sub.4-conversion, all catalytic materials in accordance with the present invention showed superior overall performance. The catalytic material in accordance with Example 1 showed the best result considering the overall performance. Similarly, it can be seen from the results shown in table 5 that the catalytic materials in accordance with Examples 1˜4 showed superior performance in comparison to Comparative Example 1. The catalytic material in accordance with Example 3 showed the best result considering the overall performance. As can be gathered from table 6 catalytic materials according to examples 1˜4 were closer to the thermodynamic conversion than Comparative Example 1. Further, Examples 2-3 are closer to the thermodynamic conversion than Comparative Example 2. It has been further shown that Comparative Example 2 presented a significant amount of undesired carbon deposits (coking). In contrast thereto, Examples 1˜4 contained a comparatively low amount of carbon. Said results clearly indicate that the catalytic materials in accordance with the present invention show superior catalytic activity and longevity with regard to the conversion of methane and carbon dioxide in comparison to the catalytic materials of the prior art represented by Comparative Examples 1 and 2.

DESCRIPTION OF THE FIGURES

[0281] FIG. 1: shows a conceptional view of a tablet having a four-hole cross-section and having four flutes. The height of a tablet is orthogonal to the shown cross-section.

[0282] FIG. 2: shows the TPR profile for Examples 1 and 2, as well as for Comparative Example 1. The thermal conductivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. Thus, the TCD signal is given in arbitrary units on the ordinate and the temperature is shown on the abscissa in ° C. The dashed line relates to Example 1, the dotted line relates to Example 2, and the solid line relates to Comparative Example 1.

[0283] FIG. 3: shows the TPR profile for Examples 3, 4, 5 and 6, as well as for Comparative Example 1. The thermal conductivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. Thus, the TCD signal is given in arbitrary units on the ordinate and the temperature is shown on the abscissa in ° C. The dashed-dotted line relates to Example 3, the grey solid line relates to Example 4, the dashed line relates to Example 5, the dotted line relates to Example 6, and the black solid line relates to Comparative Example 1.

[0284] FIG. 4: shows the TPR profile for Comparative Examples 1 and 2. The thermal conductivity detector (TCD) signal was recorded relative to the temperature to give the TPR profile. Thus, the TCD signal is given in arbitrary units on the ordinate and the temperature is shown on the abscissa in ° C. The black solid line relates to Comparative Example 1, the dashed-dotted line relates to Comparative Example 2.

CITED LITERATURE

[0285] WO 2013/068905 A1 [0286] WO 2013/118078 A1