Low Temperature Methane Steam Reforming to Produce Hydrogen

Abstract

A Low Temperature Methane Steam Reforming LTMSR catalyst is based on a non-noble metal, an alkaline earth metal and a rare earth metal combination on a support to produce stable and low temperature methane steam reforming catalysts. The catalyst is suitable for steam reforming mixtures of light hydrocarbons, such as those found in natural gas and bio-gas sources. The output may be configured to provide methane and carbon dioxide in a ratio of around 1:1 by number which is suitable for further processing into end products. The process and catalyst may help show an improved long-term performance by suppressing the fast formation of coke that is well-known to deteriorate the activity of other conventional reforming catalysts. This performance is obtained by controlling the composition and crystalline sizes of the active catalyst components on the selected support and by controlling the reaction conditions.

Claims

1-37. (canceled)

38. A process for production of hydrogen, the process comprising: reacting hydrocarbons, including methane, and water in a presence of a steam reforming catalyst within a reaction chamber at temperatures less than 550 C. to produce carbon dioxide and hydrogen; wherein the steam reforming catalyst comprises: active particles of a mixture of non-noble transition metals, alkaline earth metals and rare earth metals, the active particles having a nanocrystalline structure with domain sizes less than 25 nm, and a solid oxide support, and wherein the reaction is controlled such that a number ratio between the produced carbon dioxide to an unreacted methane exiting the reaction chamber is between 0.9 and 1.1.

39. The process according to claim 38, wherein the hydrogen is separated from the other products and unreacted reactants, and the mixture of carbon dioxide and methane is passed unto a second process to produce carbon nanofibers or petrochemicals.

40. The process according to claim 38, wherein the reforming catalyst comprises a solid support selected from the group consisting of alumina, silica, zirconia or mixtures thereof.

41. The process according to claim 40, wherein solid oxide support makes up between 45% and about 90%, by mass, of a total weight of the catalyst.

42. The process according to claim 38, wherein the steam reforming catalyst comprises a non-noble transition metal selected from nickel, cobalt, copper, manganese, iron or mixtures thereof.

43. The process according to claim 42, wherein at least a portion of the non-noble transition metals are oxidized, and a total mass of nickel oxides, cobalt oxides, copper oxides, manganese oxides or iron oxides makes up between 1% and 20%, by mass, of a total weight of the catalyst.

44. The process according to claim 38, wherein the steam reforming catalyst comprises an alkali earth metal.

45. The process according to claim 44, wherein the alkali earth metal comprises a combination of one or more of: magnesium, calcium, strontium and barium.

46. The process according to claim 44, wherein oxides of the alkali earth metal make up between 2% to 30%, by mass, of a total weight of the catalyst.

47. The process according to claim 38, wherein the steam reforming catalyst comprises a rare earth metal.

48. The process according to claim 47, wherein the rare earth metal comprises a combination of one or more of: cerium and lanthanum.

49. The process according to claim 47, wherein oxides of the rare earth metal make up between 5% and 35%, by mass, of a total weight of the catalyst.

50. The process according to claim 38, wherein the catalyst and process are configured to convert a greater proportion of ethane and propane than of methane.

51. A steam reforming catalyst comprising: a solid oxide support; and active particles mounted on the solid oxide support, the active particles comprising a mixture of non-noble transition metals, alkaline earth metals and rare earth metals, the active particles having a nanocrystalline structure with domain sizes less than 25 nm.

52. A method of preparation of the catalyst according to claim 51, the method comprising: providing the solid oxide support; and providing the active particles of a mixture of non-noble transition metals, alkaline earth metals and rare earth metals, the active particles having a nanocrystalline structure with domain sizes less than 25 nm.

53. The method according to claim 52, wherein, the method comprises: providing the solid oxide support; providing a solution precursor of a rare earth metal to the solid oxide support; thermally treating the solution precursor to provide a modified surface on the solid oxide support; and providing the active particles on the modified surface.

54. The method according to claim 53, wherein the active particles are provided by: treating the modified surface of the oxide support with a solution of a mixture of salts, the salts comprising a non-noble transition metal, an alkali earth metal and a rare earth metal combined; and thermally treating the mixture of salts to produce the active particles.

55. The method according to claim 54, wherein the steps of treating the surface with the solution of the mixture of salts and thermal treatment are repeated to build up multiple layers of active particles.

56. The method according to claim 52, wherein the method comprises activating the active particles with a reducing agent.

57. A process for production of hydrogen, the process comprising: reacting hydrocarbons, including methane, and water in a presence of a steam reforming catalyst within a reaction chamber at temperatures less than 550 C. to produce carbon dioxide and hydrogen; wherein the steam reforming catalyst comprises: active particles of a mixture of non-noble transition metals, alkaline earth metals and rare earth metals, the active particles having a nanocrystalline structure with domain sizes less than 25 nm, and a solid oxide support.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0116] Various objects, features and advantages of the present disclosure will be apparent from the following description of particular embodiments of the present disclosure, as illustrated in the accompanying drawings. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of various embodiments of the present disclosure. Similar reference numerals indicate similar components.

[0117] FIG. 1 is a graph of Green LTMSR-CO.sub.2/Unreacted-CH.sub.4 Molar Ratio vs CH.sub.4 Conversion for an embodiment of the catalyst at 500 C.

[0118] FIG. 2 is a schematic showing Global Mass Balance using a natural gas with 94% of methane and 40% of CH.sub.4 conversion in the LMTSR unit.

[0119] FIG. 3 is an XRD pattern of the material obtained in Example 1.

[0120] FIG. 4 is an XRD pattern of the material obtained in Example 2 (third layer).

[0121] FIG. 5 is an XRD pattern of the material obtained in Example 3 (third layer).

[0122] FIG. 6 is a schematic of the experimental apparatus for determining the effectiveness of a steam reforming catalyst.

[0123] FIG. 7 is a schematic diagram of a Low Temperature Steam Reforming reactor with multiple reaction chambers.

[0124] FIG. 8 is a schematic diagram of a Low Temperature Steam Reforming reactor which was used to test experimentally the efficiency of methane conversion.

[0125] FIG. 9 is a schematic diagram of a Low Temperature Steam Reforming reactor which was used to test the efficiency of methane conversion using a mathematical simulation.

DETAILED DESCRIPTION

Introduction

[0126] The present technology relates to using a low-temperature steam methane reforming (LTMSR) process to generate hydrogen while outputting carbon dioxide and methane in a ratio that is suitable for further processing into end products. The end products may be, for example, petrochemicals (e.g., ethanol) or solid carbon (e.g., in the form of carbon nanofibers) and water.

[0127] The present technology involves the use of a low-temperature steam methane reforming (LTMSR) catalyst. The LTMSR catalyst is based on a non-noble metal, an alkaline earth metal and a rare earth metal combination on a suitable support. This catalyst is suitable for steam reforming mixtures of light hydrocarbons, such as those found in natural gas and bio-gas sources, at low temperature (e.g., less than 600 C.).

[0128] The process and catalyst of the present disclosure may help provide long-term performance by suppressing the fast formation of coke that is well-known to deteriorate the activity of other conventional reforming catalysts. This performance is obtained by controlling the composition and crystalline sizes of the active catalyst components on the selected support and by controlling the reaction conditions.

[0129] The crystalline domain sizes may be controlled by adjusting one or more of the following three parameters: [0130] the thermal temperature treatment (below 500 C.);. [0131] the amount of the metal oxides in the composition and,. [0132] by the solid solution mixture of the active oxide with the alkaline earth oxide.

[0133] The reaction conditions are controlled by controlling the temperature. For example, the steam reforming reaction is carried out at relatively low temperatures of below 550 C.

[0134] The composition of two typical natural gas feedstocks is shown in Table 1. These feedstocks may be used in conjunction with the present technology to generate hydrogen and carbon nanofibers and/or petrochemicals. Table 1 also shows the output of the reactor for different conversion ratios of methane. FIG. 1 is a graph of CO.sub.2/Unreacted-CH.sub.4 Molar Ratio vs CH.sub.4 conversion for an embodiment of the catalyst at 500 C.

TABLE-US-00001 TABLE 1 Composition of natural gas and desired molar ratios for optimized production of H.sub.2 without CO.sub.2 and its ratio with respect to produced carbon nanofibers for two feedstocks. X CH.sub.4 CO.sub.2/Unreacted Feedstock CH.sub.4 C.sub.2H.sub.6 C.sub.3H.sub.8 C.sub.4H.sub.10 Conv./% H.sub.2/CO.sub.2 CH.sub.4 H.sub.2/CNF 1 94.1 3.0 2.0 1.0 10 3.61 0.298 1.804 94.1 3.0 2.0 1.0 20 3.71 0.461 1.857 94.1 3.0 2.0 1.0 30 3.78 0.669 1.888 94.1 3.0 2.0 1.0 40 3.81 0.947 1.907 94.1 3.0 2.0 1.0 50 3.84 1.337 2.568 94.1 3.0 2.0 1.0 60 3.86 1.921 3.710 94.1 3.0 2.0 1.0 70 3.88 2.895 5.614 2 80.0 10.0 6.0 4.0 10 3.45 0.861 1.726 80.0 10.0 6.0 4.0 20 3.51 1.094 1.922 80.0 10.0 6.0 4.0 30 3.56 1.393 2.482 80.0 10.0 6.0 4.0 40 3.60 1.792 3.229 80.0 10.0 6.0 4.0 50 3.64 2.350 4.275 80.0 10.0 6.0 4.0 60 3.67 3.188 5.844 80.0 10.0 6.0 4.0 70 3.69 4.583 8.458

[0135] As shown in table 1, by adjusting the conversion rate of methane, the ratio CO.sub.2 to unreacted CH.sub.4 can be adjusted to be close to 1 (see rows in bold), which is suitable for further processing, for instance, into carbon nanofibers (see WO 2020/154799 A1).

[0136] It will be appreciated that the hydrogen to CO.sub.2 product ratio for steam methane reforming of pure methane is 4. That is, steam reforming of pure methane produces 4molecules of hydrogen for every 1 molecule of carbon dioxide. As shown in table 1, for mixed alkane feedstock, the hydrogen to CO.sub.2 is changed as heavier alkanes have a lower hydrogen to carbon ratio. As table 1 shows, for the situations where the CO.sub.2/Unreacted CH.sub.4 is close to 1, the hydrogen to CO.sub.2 product ratio for steam methane reforming of common mixed alkane feedstocks is around 10% less than the pure methane number-i.e., between 3.8 and 3.5.

[0137] It will be appreciated that lowering the conversion rate of methane effectively increases the proportion of heavier alkanes being converted by the reactor. This means that the hydrogen to CO.sub.2 product ratio is reduced as the conversion rate of methane is reduced.

[0138] Even for the desired CO.sub.2/Unreacted CH.sub.4 is close to 1, this lower ratio (of between 3.8 and 3.5, or 10% less than 4) has implications for the cost of producing hydrogen. A simple estimate would indicate that the cost of hydrogen from SMR of a mixed alkane feedstock would be around 10% higher compared with a pure methane feedstock. At the same productivity rate, if conversion of pure methane produced hydrogen at $2/kg-H.sub.2, using a mixed feedstock as described in table 1 may produce hydrogen at $2.2/kg-H.sub.2. This is a relatively modest increase and may be offset by the production of a very high value carbon or petrochemical product, and by allowing the use of the process for a wider range of feedstocks. Furthermore, allowing the process to operate at a lower temperature than other steam methane reforming systems, may provide energy consumption savings (e.g., of at least 20%).

[0139] Various aspects of the technology will now be described with reference to the figures and to various specific examples. For the purposes of illustration, components depicted in the figures are not necessarily drawn to scale. Instead, emphasis is placed on highlighting the various contributions of the components to the functionality of various aspects of the present disclosure. A number of possible alternative features are introduced during the course of this description. It is to be understood that, according to the knowledge and judgment of persons skilled in the art, such alternative features may be substituted in various combinations to arrive at different embodiments of the present present disclosure.

Green Hydrogen Production

[0140] FIG. 2 is a schematic of a reactor system for producing green H.sub.2 while simultaneously producing a path to utilize the CO.sub.2 co-product.

[0141] The reactor system in this embodiment comprises: a steam reforming reactor 101, a dry reforming reactor 102 and a carbon nanofiber reactor 103. In other embodiments, the carbon nanofiber reactor may be replaced with a reactor configured to process the hydrogen and carbon monoxide (or syngas) to produce petrochemicals.

[0142] The proportions of the chemicals in FIG. 2 shows how the system might be used to process Feedstock 1 of Table 1. Feedstock 1 has a typical composition of natural gas containing 94% of methane (by number). Adjusting the conditions of the steam reforming reactor such that 40% of the methane is converted produces a CO.sub.2/unreacted CH.sub.4 number ratio at the outlet of the reactor close to 1 which represents the stoichiometry feed ratio required for dry methane reforming.

[0143] For comparison, Feedstock 2 has a lower proportion of methane and greater proportions of ethane, propane and butane than Feedstock 1. For Feedstock 2, as shown in Table 1, 20% of methane conversion in the steam reforming reactor is required to produce a CO.sub.2/unreacted CH.sub.4 number ratio at the outlet of the reactor close to 1. This illustrates the importance of allowing the reaction conditions within the steam reactor to be changed for different feedstocks to ensure a consistent output which can then be fed directly to the dry methane reforming reactor.

[0144] As shown in FIG. 2, the steam reforming reactor 101 is used to convert light hydrocarbons and water into hydrogen, which is extracted, and carbon dioxide. In addition, the reaction conditions are controlled such that a portion of the methane passes unreacted through the reactor.

[0145] The reactions for the various hydrocarbons within the steam reforming reactor are as follows:

Methane: CH.sub.4+2H.sub.2O.fwdarw.4H.sub.2+CO.sub.2

Ethane: C.sub.2H.sub.6+4H.sub.2O.fwdarw.7H.sub.2+2CO.sub.2

Propane: C.sub.3H.sub.8+6H.sub.2O.fwdarw.10H.sub.2+3CO.sub.2

Butane: C.sub.4H.sub.10+8H.sub.2O.fwdarw.13H.sub.2+4CO.sub.2

[0146] The steam reforming reactor, in this case, comprises a vessel comprising a steam reforming catalyst as described in greater detail below. The steam reforming catalyst comprises active particles of a mixture of non-noble transition metals, alkaline earth metals and rare earth metals, the active particles having a nanocrystalline structure with domain sizes less than 25 nm, and a solid oxide support. Generally, the metallic nickel has crystalline domains lower than 7 nm the Ce.sup.3+ and Ce.sup.4+ are in the same CeO.sub.2 structure that has crystalline domain sizes below 25 nm. After activation, the metallic nickel may be on the mixed oxides top that are in the support.

[0147] In this case, the steam reforming catalyst is configured to convert a greater proportion of the longer chain hydrocarbons (e.g., ethane, propane and butane) than of methane. This means that a mixed hydrocarbon feedstock can be processed through the steam reforming reactor to increase the ratio of methane with respect to the other hydrocarbons in the feedstock. This may help improve the consistency of the feedstock being provided to the next stage in the process, as compared to directing a portion of the feedstock directly into the next stage.

[0148] In this example, water in the form of steam is injected into the steam reforming reactor in excess. In this case, 3 moles of water are injected for every mole of methane. As shown in the reactions provided above, two mols of water are required to convert 1 mol of methane into hydrogen and carbon dioxide in the steam reforming process. Although there are other hydrocarbons in this feedstock, they make up a relatively small proportion so a steam/methane number ratio of 3:1 corresponds to excess steam. The unreacted water is also separated from the other gases passing through the reactor (e.g., by being condensed and separated as a liquid).

[0149] As noted above, the hydrogen produced by the steam reforming reactions is removed using a membrane.

[0150] In this embodiment, the reaction conditions are controlled such that the proportion of the unconverted methane exiting the chamber is roughly in the same proportion as the produced carbon dioxide from all the various steam reforming reactions occurring within the vessel. In this case, this can be done by adjusting the space velocity passing through the reactor. Increasing the space velocity reduces the conversion rate of methane passing through the reactor.

[0151] In this system, the carbon dioxide product of the steam reforming and the unconverted methane are injected into a dry methane reforming reactor 102. The dry methane reforming reactor comprises a vessel with a dry reforming catalyst and is configured to convert the carbon dioxide and methane into hydrogen and carbon monoxide:

CH.sub.4+CO.sub.2.fwdarw.2H.sub.2+2CO

[0152] In this case, the hydrogen is not separated from the other reactants, but instead is passed with the carbon monoxide to the final stage in the process. In this embodiment over 90% by number of the methane molecules injected into the dry reforming reactor is converted. Any excess is separated from the reactants and recycled, in this case, to the steam reforming reactor. Having a small excess of methane in the dry reforming reactor may help ensure that an excess of carbon dioxide does not pass through the dry methane reforming. This may facilitate the separation of unwanted reactants from the products of the dry reforming process.

[0153] In this system, the conditions of the dry methane reforming reactor are configured to convert the majority of the methane and carbon dioxide into the hydrogen and carbon monoxide products.

[0154] In the final stage, the hydrogen and carbon monoxide produced in the dry reforming reactor is passed into a carbon nanofiber reactor 103. This comprises a vessel comprising a nanofibre catalyst for producing carbon nanofibers. This reactor allows the conversion of equal volumes or numbers of hydrogen and carbon monoxide into carbon nanofibers and water:

H.sub.2+CO.fwdarw.C+H.sub.2O

[0155] The water may be recycled for steam reforming.

[0156] The overall process, in this case, produces no carbon dioxide because the carbon dioxide produced in the steam reforming reactor is subsequently used to produce solid carbon in the form of carbon nanofibers. Assuming a feedstock of pure methane, the overall reaction for the process is as follows:

Steam Reforming (+passing CH.sub.4): CH.sub.4+2H.sub.2O (+CH.sub.4).fwdarw.4H.sub.2+CO.sub.2 (+CH.sub.4)

Dry methane reforming: CH.sub.4+CO.sub.2.fwdarw.2H.sub.2+2CO

Carbon Production: 2H.sub.2+2CO.fwdarw.2C+2H.sub.2O

Overall reaction: 2CH.sub.4.fwdarw.4H.sub.2+2C

[0157] This technology allows green hydrogen production using SMR with a much lower temperature. This may improve the economics of the steam reforming process, provide a cleaner use for existing hydrocarbon reserves (such as natural gas), produce a useful carbon nanomaterial, and reduce the GHG emissions of current industrial practice.

[0158] The produced syngas also can be used for production of petrochemicals of high value. Some produced hydrogen can be redirected to increase the H.sub.2/CO ratio of the produced syngas for selective production of methanol, formic acid, ethanol, etc.

Catalyst

[0159] As described above, the steam reforming catalyst comprises: [0160] active particles of a mixture of non-noble transition metals, alkaline earth metals and rare earth metals, the active particles having a nanocrystalline structure with domain sizes less than 25 nm, and [0161] a solid oxide support.

[0162] The rare earth elements may comprise one or more of: scandium (Sc), yttrium (Y), and a lanthanide.

[0163] The alkaline earth metals may comprise one or more of: magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba).

[0164] The noble metals include ruthenium (Ru), rhodium (Rh), palladium (Pd), Rhenium (Rh), osmium (Os), iridium (Ir), platinum (Pt), gold (Au) and silver (Ag). Therefore, a non-noble transition metal may include one or more of: nickel, cobalt, manganese, iron and copper.

[0165] The solid oxide support may comprise one or more of: alumina, silica and zirconia. The mass proportions of the catalyst may be as follows: [0166] solid oxide support: 45%-90%; [0167] oxides of the non-noble transition metals (e.g., NiO, Ni.sub.2O.sub.3, CoO, Co.sub.2O.sub.3 Co.sub.3O.sub.4, MnO, Mn.sub.2O.sub.3, Mn.sub.3O.sub.4, CuO, Cu.sub.2O, FeO, Fe.sub.2O.sub.3, Fe.sub.3O.sub.4 and/or ZnO): 1%-20%; [0168] alkali earth metal: 2%-30%; and [0169] oxides of the rare earth metal: 5%-35%.

[0170] Regarding the size of the nanocrystalline domain size, the sizes may be considered to relate to an average three-dimensional size as there is no apparent preferential orientation of the oxides in the X-ray diffraction pattern and all the crystalline planes of the oxide structures correspond to values of less than 25 nm.

[0171] The size of the nanocrystalline domain size is calculated using the Scherrer equation (e.g., via x-ray diffraction, XRD). The dimension is an average of the different crystalline planes which in all the planes for these catalysts may be lower than 25 nm. The inventors have found that for these catalysts, there is not a visible preferential growth of the crystals in the X-ray diffraction pattern. The conventional shape factor of 0.9 is used as implemented in the software.

[0172] After activation, the metals are generally present in the form of oxides. The only two that after activation can have a metallic component are the non-noble transition metals (e.g., nickel and copper). Most of the nickel will be in an oxide form NiO mixed in a solid solution with MgO with a small part being a very tiny metallic cluster. The CeO.sub.2 will have some parts of the cerium as Ce.sup.4+ (more abundant) and Ce.sup.3+ less abundant but the two of them in the same CeO.sub.2 structure.

[0173] Catalyst Examples

[0174] The low temperature reforming catalysts of the present disclosure, their preparation methods and their use for low temperature steam reforming of light hydrocarbons, natural gas and bio-oils will be better understood by reference to the following examples.

[0175] The raw materials used for the preparation of the materials referenced in the examples were obtained from Sigma Aldrich and Sasol; these are: cerium nitrate hexahydrate (Ce(NO.sub.3).sub.3.Math.6H.sub.2O), nickel nitrate hexahydrate (Ni(NO.sub.3).sub.2.Math.6H.sub.2O), magnesium nitrate hexahydrate (Mg(NO.sub.3).sub.2.Math.6H.sub.2O), cobalt nitrate hexahydrate (Co(NO.sub.3).sub.2.Math.6H.sub.2O), copper nitrate hemi (pentahydrate) (Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O), manganese nitrate hexahydrate (Mn(NO.sub.3).sub.2.Math.6H.sub.2O), calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2.Math.4H.sub.2O), iron(II) sulfate heptahydrate (FeSO.sub.4.Math.7H.sub.2O), Lanthanum nitrate hexahydrate (La(NO.sub.3).sub.3.Math.6H.sub.2O) and gamma-alumina (-Al.sub.2O.sub.3) spheres of 1 mm diameter.

[0176] The examples show the preparation of some useful low temperature reforming catalysts of the present disclosure as well as the activation of the materials of the present disclosure and its use as catalysts for the low temperature reforming of light hydrocarbons, natural gas or bio-oil. These experiments are cited only as examples it will be appreciated that other variations would be possible.

[0177] These Examples relate to results obtained in a continuous steam reforming reactor working at a Steam/C Molar Ratio=5 and P=30 psig are described below for our catalyst performing at a mass space velocity of 1300 h.sup.1 generating a conversion higher than 70% of methane when this reactant is in the range of concentrations between 94% and 80% volume content of the hydrocarbon feedstock. The temperature used is in the range of 500-550 C., which is about 300 C. lower than conventional SMR. These features provide a significant and original advantage by reducing the energy consumption of SMR by up to 35%, while using the same SMR infrastructure installed worldwide.

[0178] The steam reforming catalyst described herein can operate at 5-20 times that space velocity to achieve the lowest methane conversion (40% to 20% as per table 1) required to match the desired CO.sub.2/unreacted CH.sub.4 proportion of around 1. Therefore, this provides a much higher productivity, comparable to the SMR at conventional high temperature. For comparison, it will be appreciated that for a pure methane feedstock, a conversion rate of 50% would be required to ensure that the output of the steam reforming reactor has a CO.sub.2/unreacted CH.sub.4 proportion of around 1.

[0179] This confirms the possibility of simply retrofitting existing SMR units, and adding the carbon nanofiber production stages.

[0180] Table 2 below shows the XRD domain sizes and textural properties of the various layers of three examples. These materials were also used in the testing of the catalytic properties for low temperature steam reforming of the present technology.

[0181] The proportions by mass of the components in these three catalysts are: [0182] 1st-layer: % Al.sub.2O.sub.3=81.6; % CeO.sub.2=13.2; % NiO=2.2 and % MgO=3.0 with a Ni/Ce atomic ratio of 0.38; a Mg/Ni atomic ratio of 2.5 and a Mg/Ce atomic ratio of 0.96. [0183] 2nd-layer: % Al.sub.2O.sub.3=76.1; % CeO.sub.2=14.3; % NiO=4.1 and % MgO=5.5 with a Ni/Ce atomic ratio of 0.65; a Mg/Ni atomic ratio of 2.5 and a Mg/Ce atomic ratio of 1.65. [0184] 3rd-layer: % Al.sub.2O.sub.3=71.2; % CeO.sub.2=15.3; % NiO=5.7 and % MgO=7.8 with a Ni/Ce atomic ratio of 0.86; a Mg/Ni atomic ratio of 2.5 and a Mg/Ce atomic ratio of 2.2.

TABLE-US-00002 TABLE 2 XRD average crystalline domain sizes and textural properties of the produced materials of Examples 1-3. XRD average crystalline External BJH Pore domain sizes [nm] BET area Micro area area volume BJH Pore Sample CeO.sub.2 NiO MgO Ni [m.sup.2/g] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] size [nm] Example 1 7.9 131.4 6.5 124.9 0.3833 8.12 Example 2 8.3 5.6 5.6 124.5 10.9 113.6 0.3310 7.89 (1.sup.st-layer) Example 2 8.9 5.6 5.6 118.3 9.2 109.1 0.2931 7.72 (2.sup.nd-layer) Example 2 8.9 5.7 5.7 116.6 8.9 107.7 0.2707 7.24 (3.sup.rd-layer) Example 3 8.7 3.7 3.7 <2 117.3 8.7 108.5 0.3530 8.04 (1.sup.st-layer) Example 3 8.7 5.3 5.3 <2 102.3 9.5 92.8 0.3098 7.89 (2.sup.nd-layer) Example 3 9.3 6.1 6.1 <3 89.5 12.2 77.3 0.2609 7.56 (3.sup.rd-layer)

Example 1: Modification of the Alumina Surface With CeO.SUB.2

[0185] A solution of cerium nitrate was prepared by dissolving 248 grams of cerium nitrate in 270 mL of deionized water. This solution was added to the dispenser to be added with a flow of 10 mL/min under the air nozzle over 720 grams of -Al.sub.2O.sub.3 spheres contained inside of the pan of the impregnating machine (or coating machine) which was rotating at 30 rpm. After the solution was added, the impregnated spheres were allowed to rotate for 30 minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 30minutes. The impregnated spheres were transferred to stainless steel trays and placed in the oven to dry them at 100 C. for 3 hours and then calcined at 400 C. for 12 hours with a ramp of 5 C./min. FIG. 3 and Table 2 show the XRD pattern of the calcined material and the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 2: Incorporation of NiO, MgO and CeO.SUB.2 .on the CeO.SUB.2.-Modified Alumina

[0186] A solution of nickel nitrate, magnesium nitrate and cerium nitrate was prepared by dissolving 225 grams of nickel nitrate, 140 grams of cerium nitrate and 500 grams of magnesium nitrate in 580 mL of deionized water. The obtained solution was divided in three portions to be added by three successive impregnations as follows:

[0187] 818 grams of the produced CeO.sub.2-modified alumina were incorporated inside the impregnator's pan and rotated at 30 rpm. The first portion of the mixed metal solution was added to the dispenser and flowed at a rate of 10 mL/min under the air nozzle. After the solution was added, the impregnated spheres were allowed to rotate for 30 minutes at 30rpm; after this time, hot air was introduced in the pan chamber for 50 minutes. The impregnated spheres were transferred to stainless steel trays and place in the oven to dry them at 100 C. for 3 hours and then calcine them at 400 C. for 12 hours with a ramp of 5 C./min producing in this way Example 2 1.sup.st-layer. After the spheres were calcined, they were placed back into the impregnator's pan to carry out the second impregnation with the second portion of the solution using the same protocol of the first impregnation producing in this way Example 2 2.sup.nd-layer. After the calcination, the produced material was again placed inside the impregnator's pan and its impregnation was carried out in the same fashion with the last portion of the solution producing in this way Example 2 3.sup.rd-layer. FIG. 4 and Table 2 show the XRD pattern of the calcined material and the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

[0188] The final temperature is an important parameter for determining the nanocrystalline domain sizes we are targeting. The higher the temperature the higher the nanocrystalline domain sizes will be but after 700 C. the oxides will begin to react with the alumina to form spinel mixed oxides which are not easy to reduce and require a high temperature to obtain the metallic nickel. The presently disclosed method of producing the catalyst ensures that the nickel is available for reduction but not all of it as we require very small crystalline domain sizes.

[0189] The temperature ramp can also influence the diffusion of the gases produced by the decomposition of the salts used to impregnate the support. A very fast ramp may be an inferior choice because the gases produced by decomposition of the salts generate a high pressure within the support that can break or damage the alumina spheres.

[0190] In general, the dried impregnated spheres are heated to a temperature of at least 450 C. for at least 6 hours with a ramp of no more than 15 C./min.

Example 3: Activation of the Catalyst of Example 2 for Steam Reforming

[0191] The activation of the catalyst generally must be performed in situ within the steam reforming reactor and, to obtain the best performance, it is advised to carry it out right before the run with the selected feedstock to avoid any possible pre-oxidation of the active sites.

[0192] Before starting the activation protocol, in this case, the system is purged with an inert gas (such as nitrogen), and then with hydrogen to move the air out of the unit.

[0193] For this purpose, nitrogen is flowed through the reactor at 100 mL/min during at least 30 minutes or until no oxygen is detected anymore by Gas Chromatography (GC) and/or Quadrupole Mass Spectrometry (QMS). Then, the nitrogen gas is changed to hydrogen gas, which is flowed through the reactor at 100 mL/min during few hours (e.g. 5hours or more) or until no nitrogen is detected anymore by Gas Chromatography (GC) and/or Quadrupole Mass Spectrometry (QMS).

[0194] To start the reduction, hydrogen is flowed through the reactor filled with the catalyst at 100 mL/min and atmospheric pressure, the temperature is increased from room temperature to 500 C. with a ramp of 10 C./min. After the temperature of 500 C. is reached, the system is pressurized at 86 psig. The produced mixture of gases generated during the activation process was followed by a Quadrupole Mass Spectrometry (QMS) to check on the profile of the produced gases which is going to indicate the end of the activation protocol when hydrogen is stabilized (not consumed/produced) and the other gases reach background levels. The temperature is maintained at 500 C. for approximately 16 hours. This time may have to be adjusted if the used pressure is lower than 86 psig and, of course, based on the results obtained by the QMS.

[0195] FIG. 5 and Table 2 shows the XRD powder diffraction pattern of a sample of the activated material and the average crystalline domain sizes measured by XRD as well as its textural properties, respectively. In this case, the final catalyst composition comprises: CeO.sub.2, NiO, MgO and Ni. That is, the non-noble transition metal is nickel, the alkaline earth metal is magnesium, and the rare earth metal is Cerium.

[0196] The mass proportions of the components in this catalyst are % Al.sub.2O.sub.3=71.2; % CeO.sub.2=15.3; % NiO=5.7 and % MgO=7.8 with a Ni/Ce atomic ratio of 0.86; a Mg/Ni atomic ratio of 2.5 and a Mg/Ce atomic ratio of 2.2.

Additional Catalyst Examples

[0197] The raw materials used for the preparation of the materials referenced in the examples were obtained from Sigma Aldrich and Sasol; these are: cerium nitrate hexahydrate (Ce(NO.sub.3).sub.3.Math.6H.sub.2O), nickel nitrate hexahydrate (Ni(NO.sub.3).sub.2.Math.6H.sub.2O), magnesium nitrate hexahydrate (Mg(NO.sub.3).sub.2.Math.6H.sub.2O), cobalt nitrate hexahydrate (Co(NO.sub.3).sub.2.Math.6H.sub.2O), copper nitrate hemi (pentahydrate) (Cu(NO.sub.3).sub.2.Math.2.5H.sub.2O), manganese nitrate hexahydrate (Mn(NO.sub.3).sub.2.Math.6H.sub.2O), calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2.Math.4H.sub.2O), iron(II) sulfate heptahydrate (FeSO.sub.4.Math.7H.sub.2O), Lanthanum nitrate hexahydrate (La(NO.sub.3).sub.3.Math.6H.sub.2O) and gamma-alumina (-Al.sub.2O.sub.3) spheres of 1 mm diameter.

Example 4: Modification of the Alumina Surface With CeO.SUB.2 .to Prepare Other Variations of the Catalysts of the Present Present Disclosure

[0198] A solution of cerium nitrate was prepared by dissolving 104 grams of cerium nitrate in 122 mL of deionized water. This solution was added to the dispenser to be added with a flow of 10 mL/min under the air nozzle over 300 grams of -Al.sub.2O.sub.3 spheres contained inside of the pan of the impregnating machine (or coating machine) which was rotating at 30 rpm. After the solution was added, the impregnated spheres were allowed to rotate for 30 minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 30 minutes. The impregnated spheres were transferred to stainless steel trays and placed in the oven to dry them at 100 C. for 3 hours and then calcined at 400 C. for 12 hours with a ramp of 5 C./min. Table 3 show the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 5: Incorporation of Co.SUB.3.O.SUB.4., MgO and CeO.SUB.2 .on the CeO.SUB.2.-Modified Alumina of Example 4

[0199] A solution of cobalt nitrate, magnesium nitrate and cerium nitrate was prepared by dissolving 13.748 grams of cobalt nitrate, 8.649 grams of cerium nitrate and 30.674 grams of magnesium nitrate in 47.7 mL of deionized water. The obtained solution was divided in three portions to be added by three successive impregnations as follows:

[0200] 50 grams of the produced CeO.sub.2-modified alumina of Example 4 were incorporated inside the impregnator's pan and rotated at 30 rpm. The first portion of the mixed metal solution was added to the dispenser and flowed at a rate of 10 mL/min under the air nozzle. After the solution was added, the impregnated spheres were allowed to rotate for 10minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 10minutes. The impregnated spheres were transferred to stainless steel trays and place in the oven to dry them at 100 C. for 3 hours and then calcine them at 400 C. for 12 hours with a ramp of 5 C./min producing in this way Example 5 1.sup.st-layer. After the spheres were calcined, they were placed back into the impregnator's pan to carry out the second impregnation with the second portion of the solution using the same protocol of the first impregnation. After the calcination producing in this way Example 5 2.sup.nd-layer, the produced material was again placed inside the impregnator's pan and its impregnation was carried out in the same fashion with the last portion of the solution producing in this way Example 5 3.sup.rd-layer. Table 3 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 6: Activation of the Catalyst of Example 5 for Steam Reforming

[0201] The activation of the catalysts of Example 5 was carried out in the same fashion as those of Example 3. Table 3 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively. In this case, the final catalyst composition comprises: CeO.sub.2, Co.sub.3O.sub.4, and MgO. That is, the non-noble transition metal is cobalt, the alkaline earth metal is magnesium, and the rare earth metal is Cerium.

[0202] The mass proportions of the components in these three catalysts are: [0203] 1.sup.st-layer: % Al.sub.2O.sub.3=81.6; % CeO.sub.2=13.2; % CoO=2.2 and % MgO=3.0 with a Co/Ce atomic ratio of 0.38; a Mg/Co atomic ratio of 2.5 and a Mg/Ce atomic ratio of 0.96. [0204] 2.sup.nd-layer: % Al.sub.2O.sub.3=76.0; % CeO.sub.2=14.3; % CoO=4.1 and % MgO=5.6 with a Co/Ce atomic ratio of 0.65; a Mg/Co atomic ratio of 2.5 and a Mg/Ce atomic ratio of 1.65. [0205] 3.sup.rd-layer: % Al.sub.2O.sub.3=71.2; % CeO.sub.2=15.3; % CoO=5.7 and % MgO=7.8 with a Co/Ce atomic ratio of 0.86; a Mg/Co atomic ratio of 2.5 and a Mg/Ce atomic ratio of 2.2.

TABLE-US-00003 TABLE 3 XRD average crystalline domain sizes and textural properties of the produced materials of Examples 4, 5 and 6. XRD average crystalline External BJH Pore domain sizes [nm] BET area Micro area area volume BJH Pore Sample CeO.sub.2 Co.sub.3O.sub.4 MgO Co [m.sup.2/g] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] size [nm] Example 4 8.4 137.3 10.4 126.9 0.3787 7.84 Example 5 8.4 5.6 5.9 119.4 10.5 108.8 0.3325 7.99 (1.sup.st-layer) Example 5 8.9 6.3 6.8 119.5 7.5 112.0 0.3142 7.71 (2.sup.nd-layer) Example 5 8.8 17.0 8.6 101.5 4.9 96.6 0.2600 7.37 (3.sup.rd-layer) Example 6 8.7 4.7 2.7 119.5 119.5 0.3995 8.92 (1.sup.st-layer) Example 6 8.7 4.7 10.0 105.7 8.4 97.3 0.3029 7.94 (2.sup.nd-layer) Example 6 8.9 6.7 6.6 90.3 8.1 82.2 0.2752 7.82 (3.sup.rd-layer)

Example 7: Incorporation of CuO, MgO and CeO.SUB.2 .on the CeO.SUB.2.-Modified Alumina of Example 4

[0206] A solution of copper nitrate, magnesium nitrate and cerium nitrate was prepared by dissolving 11.041 grams of copper nitrate, 8.660 grams of cerium nitrate and 30.751 grams of magnesium nitrate in 47.7 mL of deionized water. The obtained solution was divided in three portions to be added by three successive impregnations as follows:

[0207] 50 grams of the produced CeO2-modified alumina of Example 4 were incorporated inside the impregnator's pan and rotated at 30 rpm. The first portion of the mixed metal solution was added to the dispenser and flowed at a rate of 10 mL/min under the air nozzle. After the solution was added, the impregnated spheres were allowed to rotate for 10 minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 10 minutes. The impregnated spheres were transferred to stainless steel trays and place in the oven to dry them at 100 C. for 3 hours and then calcine them at 400 C. for 12 hours with a ramp of 5 C./min producing in this way Example 7 1.sup.st-layer. After the spheres were calcined, they were placed back into the impregnator's pan to carry out the second impregnation with the second portion of the solution using the same protocol of the first impregnation. After the calcination, producing in this way Example 7 2.sup.nd-layer, the produced material was again placed inside the impregnator's pan and its impregnation was carried out in the same fashion with the last portion of the solution producing in this way Example 7 3.sup.rd-layer. Table 4 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 8: Activation of the Catalyst of Example 7 for Steam Reforming

[0208] The activation of the catalysts of Example 7 was carried out in the same fashion as those of Example 3. Table 4 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively. In this case, the final catalyst composition comprises: CeO.sub.2, CuO, MgO and Cu. That is, the non-noble transition metal is copper, the alkaline earth metal is magnesium, and the rare earth metal is Cerium.

[0209] The mass proportions of the components in these three catalysts are: [0210] 1.sup.st-layer: % Al.sub.2O.sub.3=81.4; % CeO.sub.2=13.3; % CuO=2.3 and % MgO=3.0 with a Cu/Ce atomic ratio of 0.38; a Mg/Cu atomic ratio of 2.5 and a Mg/Ce atomic ratio of 0.96. [0211] 2.sup.nd-layer: % Al.sub.2O.sub.3=75.8; % CeO.sub.2=14.3; % CuO=4.3 and % MgO=5.6 with a Cu/Ce atomic ratio of 0.65; a Mg/Cu atomic ratio of 2.5 and a Mg/Ce atomic ratio of 1.65. [0212] 3.sup.rd-layer: % Al.sub.2O.sub.3=70.9; % CeO.sub.2=15.2; % CuO=6.1 and % MgO=7.8 with a Cu/Ce atomic ratio of 0.86; a Mg/Cu atomic ratio of 2.5 and a Mg/Ce atomic ratio of 2.2.

TABLE-US-00004 TABLE 4 XRD average crystalline domain sizes and textural properties of the produced materials of Examples 7 and 8. XRD average crystalline External BJH Pore domain sizes [nm] BET area Micro area area volume BJH Pore Sample CeO.sub.2 CuO MgO Cu [m.sup.2/g] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] size [nm] Example 7 8.4 5.6 1.9 129.1 10.0 119.1 0.3657 8.01 (1.sup.st-layer) Example 7 8.4 5.0 2.4 100.8 10.0 90.8 0.3133 7.73 (2.sup.nd-layer) Example 7 8.4 5.0 3.6 109.4 8.4 101.0 0.2984 7.62 (3.sup.rd-layer) Example 8 8.5 3.8 5.4 117.6 117.6 0.4205 8.04 (1.sup.st-layer) Example 8 8.4 4.6 5.5 100.7 5.7 95.0 0.2924 7.95 (2.sup.nd-layer) Example 8 8.5 4.9 10.3 93.7 8.7 85.0 0.2765 7.85 (3.sup.rd-layer)

Example 9: Incorporation of MnO, MgO and CeO.SUB.2 .on the CeO.SUB.2.-Modified Alumina of Example 4

[0213] A solution of manganese nitrate, magnesium nitrate and cerium nitrate was prepared by dissolving 11.826 grams of manganese nitrate, 8.594 grams of cerium nitrate and 30.556 grams of magnesium nitrate in 47.7 mL of deionized water. The obtained solution was divided in three portions to be added by three successive impregnations as follows:

[0214] 50 grams of the produced CeO.sub.2-modified alumina of Example 4 were incorporated inside the impregnator's pan and rotated at 30 rpm. The first portion of the mixed metal solution was added to the dispenser and flowed at a rate of 10 mL/min under the air nozzle. After the solution was added, the impregnated spheres were allowed to rotate for 10 minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 10 minutes. The impregnated spheres were transferred to stainless steel trays and place in the oven to dry them at 100 C. for 3 hours and then calcine them at 400 C. for 12 hours with a ramp of 5 C./min producing in this way Example 9 1.sup.st-layer. After the spheres were calcined, they were placed back into the impregnator's pan to carry out the second impregnation with the second portion of the solution using the same protocol of the first impregnation. After the calcination, producing in this way Example 9 2.sup.nd-layer, the produced material was again placed inside the impregnator's pan and its impregnation was carried out in the same fashion with the last portion of the solution producing in this way Example 2 3.sup.rd-layer. Table 5 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 10: Activation of the Catalyst of Example 9 for Steam Reforming

[0215] The activation of the catalysts of Example 9 was carried out in the same fashion as those of Example 3. Table 5 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively. In this case, the final catalyst composition comprises: CeO.sub.2, MnO and MgO. That is, the non-noble transition metal is manganese, the alkaline earth metal is magnesium, and the rare earth metal is Cerium.

[0216] The mass proportions of the components in these three catalysts are: [0217] 1.sup.st-layer: % Al.sub.2O.sub.3=81.7; % CeO.sub.2=13.3; % MnO=2.0 and % MgO=3.0 with a Mn/Ce atomic ratio of 0.38; a Mg/Mn atomic ratio of 2.5 and a Mg/Ce atomic ratio of 0.95. [0218] 2.sup.nd-layer: % Al.sub.2O.sub.3=76.2; % CeO.sub.2=14.4; % MnO=3.9 and % MgO=5.5 with a Mn/Ce atomic ratio of 0.65; a Mg/Mn atomic ratio of 2.5 and a Mg/Ce atomic ratio of 1.65. [0219] 3.sup.rd-layer: % Al.sub.2O.sub.3=71.5; % CeO.sub.2=15.3; % MnO=5.4 and % MgO=7.8 with a Mn/Ce atomic ratio of 0.86; a Mg/Mn atomic ratio of 2.5 and a Mg/Ce atomic ratio of 2.2.

TABLE-US-00005 TABLE 5 XRD average crystalline domain sizes and textural properties of the produced materials of Examples 9 and 10. XRD average crystalline External BJH Pore domain sizes [nm] BET area Micro area area volume BJH Pore Sample CeO.sub.2 MnO MgO Mn [m.sup.2/g] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] size [nm] Example 9 8.8 7.0 3.8 120.2 6.3 113.9 0.3265 7.98 (1.sup.st-layer) Example 9 8.1 6.3 4.7 123.9 6.5 117.4 0.3287 7.76 (2.sup.nd-layer) Example 9 8.3 4.7 5.9 98.2 3.5 94.7 0.2493 7.10 (3.sup.rd-layer) Example 10 8.5 3.4 5.7 119.2 119.2 0.3541 8.05 (1.sup.st-layer) Example 10 8.1 6.2 4.8 5.3 101.8 11.1 90.7 0.2868 7.54 (2.sup.nd-layer) Example 10 8.4 5.4 5.3 5.4 95.6 9.6 86.0 0.2706 7.54 (3.sup.rd-layer)

Example 11: Incorporation of FeO, MgO and CeO.SUB.2 .on the CeO.SUB.2.-Modified Alumina of Example 4

[0220] A solution of iron (II) nitrate was prepared by dissolving iron (II) sulfate in deionized water and adding a solution of calcium nitrate under agitation. A calcium sulfate precipitate was formed, and a green solution of iron (II) nitrate was obtained. The mixture was filtrated to remove the precipitated calcium sulfate and to obtain the iron (II) nitrate solution for further use. To prepare this Iron (II) nitrate solution 13.233 grams of iron (II) sulfate and 11.250 grams of calcium nitrate were used. To this iron (II) nitrate solution, magnesium nitrate and cerium nitrate were added by dissolving 8.598 grams of cerium nitrate and 30.516 grams of magnesium nitrate. The obtained solution was divided in three portions to be added by three successive impregnations as follows:

[0221] 50 grams of the produced CeO.sub.2-modified alumina of Example 4 were incorporated inside the impregnator's pan and rotated at 30 rpm. The first portion of the mixed metal solution was added to the dispenser and flowed at a rate of 10 mL/min under the air nozzle. After the solution was added, the impregnated spheres were allowed to rotate for 10 minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 10 minutes. The impregnated spheres were transferred to stainless steel trays and place in the oven to dry them at 100 C. for 3 hours and then calcine them at 400 C. for 12 hours with a ramp of 5 C./min producing in this way Example 11 1.sup.st-layer. After the spheres were calcined, they were placed back into the impregnator's pan to carry out the second impregnation with the second portion of the solution using the same protocol of the first impregnation. After the calcination, producing in this way Example 11 2.sup.nd-layer, the produced material was again placed inside the impregnator's pan and its impregnation was carried out in the same fashion with the last portion of the solution producing in this way Example 11 3.sup.rd-layer. Table 6 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 12: Activation of the Catalyst of Example 11 for Steam Reforming

[0222] The activation of the catalysts of Example 11 was carried out in the same fashion as those of Example 3. Table 6 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively. In this case, the final catalyst composition comprises: CeO.sub.2, FeO and MgO. That is, the non-noble transition metal is iron, the alkaline earth metal is magnesium, and the rare earth metal is Cerium.

[0223] The mass proportions of the components in these three catalysts are: [0224] 1.sup.st-layer: % Al.sub.2O.sub.3=81.6; % CeO.sub.2=13.3; % FeO=2.1 and % MgO=3.0 with a Fe/Ce atomic ratio of 0.38; a Mg/Fe atomic ratio of 2.5 and a Mg/Ce atomic ratio of 0.95. [0225] 2.sup.nd-layer: % Al.sub.2O.sub.3=76.2; % CeO.sub.2=14.4; % FeO=3.9 and % MgO=5.5 with a Fe/Ce atomic ratio of 0.65; a Mg/Fe atomic ratio of 2.5 and a Mg/Ce atomic ratio of 1.65. [0226] 3.sup.rd-layer: % Al.sub.2O.sub.3=71.4; % CeO.sub.2=15.3; % FeO=5.5 and % MgO=7.8 with a Fe/Ce atomic ratio of 0.87; a Mg/Fe atomic ratio of 2.5 and a Mg/Ce atomic ratio of 2.2.

TABLE-US-00006 TABLE 6 XRD average crystalline domain sizes and textural properties of the produced materials of Examples 11 and 12. XRD average crystalline External BJH Pore domain sizes [nm] BET area Micro area area volume BJH Pore Sample CeO.sub.2 Fe.sub.2O.sub.3 MgO Fe.sub.3O.sub.4 [m.sup.2/g] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] size [nm] Example 11 8.2 4.4 3.6 140.3 8.4 131.9 0.3738 7.41 (1.sup.st-layer) Example 11 7.8 5.4 5.0 106.8 6.5 100.3 0.2994 7.77 (2.sup.nd-layer) Example 11 7.8 5.7 3.3 80.5 4.9 75.6 0.2074 7.23 (3.sup.rd-layer) Example 12 8.5 4.1 3.5 115.0 7.3 107.7 0.3293 7.71 (1.sup.st-layer) Example 12 8.4 4.1 3.1 121.6 10.4 111.2 0.3616 7.97 (2.sup.nd-layer) Example 12 8.6 4.9 5.4 101.1 4.0 97.1 0.2842 7.34 (3.sup.rd-layer)

Example 13: Incorporation of CuO, CaO, La.SUB.2.O.SUB.3 .and CeO.SUB.2 .on the CeO.SUB.2.-Modified Alumina of Example 4

[0227] A solution of copper nitrate, calcium nitrate and lanthanum nitrate was prepared by dissolving 11.049 grams of copper nitrate, 8.661 grams of lanthanum nitrate and 28.448 grams of calcium nitrate in 47.7 mL of deionized water. The obtained solution was divided in three portions to be added by three successive impregnations as follows:

[0228] 50 grams of the produced CeO.sub.2-modified alumina of Example 4 were incorporated inside the impregnator's pan and rotated at 30 rpm. The first portion of the mixed metal solution was added to the dispenser and flowed at a rate of 10 mL/min under the air nozzle. After the solution was added, the impregnated spheres were allowed to rotate for 10 minutes at 30 rpm; after this time, hot air was introduced in the pan chamber for 10 minutes. The impregnated spheres were transferred to stainless steel trays and place in the oven to dry them at 100 C. for 3 hours and then calcine them at 400 C. for 12 hours with a ramp of 5 C./min producing in this way Example 13 1.sup.st-layer. After the spheres were calcined, they were placed back into the impregnator's pan to carry out the second impregnation with the second portion of the solution using the same protocol of the first impregnation. After the calcination, producing in this way Example 13 2.sup.nd-laye, the produced material was again placed inside the impregnator's pan and its impregnation was carried out in the same fashion with the last portion of the solution producing in this way Example 13 3.sup.rd-layer. Table 7 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively.

Example 14: Activation of the Catalyst of Example 13 for Steam Reforming

[0229] The activation of the catalysts of Example 13 was carried out in the same fashion as those of Example 3. Table 7 shows the average crystalline domain sizes measured by XRD as well as its textural properties, respectively. In this case, the final catalyst composition comprises: CeO.sub.2, CuO, CaO and La.sub.2O.sub.3. That is, the non-noble transition metal is copper, the alkaline earth metal is calcium, and the rare earth metals are Cerium and Lanthanum.

[0230] The mass proportions of the components in these three catalysts are: [0231] 1.sup.st-layer: % Al.sub.2O.sub.3=80.6; % CeO.sub.2=11.0; % CuO=2.3, % CaO=4.1 and % La.sub.2O.sub.3=2.0 with a Cu/Ce atomic ratio of 0.45; a Ca/Cu atomic ratio of 2.5 and a Ca/Ce atomic ratio of 1.14, Cu/La atomic ratio of 2.4; Ca/La atomic ratio of 6.0, Ce/La atomic ratio of 5.3. [0232] 2.sup.nd-layer: % Al.sub.2O.sub.3=74.4; % CeO.sub.2=10.2; % CuO=4.2, % CaO=7.6 and % La.sub.2O.sub.3=3.6 with a Cu/Ce atomic ratio of 0.90; a Ca/Cu atomic ratio of 2.5 and a Ca/Ce atomic ratio of 2.3, Cu/La atomic ratio of 2.4; Ca/La atomic ratio of 6.0, Ce/La atomic ratio of 2.6. [0233] 3.sup.rd-layer: % Al.sub.2O.sub.3=69.1; % CeO.sub.2=9.4; % CuO=5.9, % CaO=10.5 and % La.sub.2O.sub.3=5.1 with a Cu/Ce atomic ratio of 1.35; a Ca/Cu atomic ratio of 2.5 and a Ca/Ce atomic ratio of 3.4, Cu/La atomic ratio of 2.4; Ca/La atomic ratio of 6.0, Ce/La atomic ratio of 1.8.

TABLE-US-00007 TABLE 7 XRD average crystalline domain sizes and textural properties of the produced materials of Examples 13 and 14. XRD average crystalline External BJH Pore domain sizes [nm] BET area Micro area area volume BJH Pore Sample CeO.sub.2 CuO CaO La.sub.2O.sub.3 Cu [m.sup.2/g] [m.sup.2/g] [m.sup.2/g] [cm.sup.3/g] size [nm] Example 13 8.5 3.9 3.8 5.4 89.4 11.0 78.4 0.2389 7.12 (1.sup.st-layer) Example 13 8.7 5.3 5.6 6.5 99.0 12.0 87.0 0.3084 7.86 (2.sup.nd-layer) Example 13 8.5 23.0 5.8 6.5 69.6 8.2 61.4 0.2020 7.29 (3.sup.rd-layer) Example 14 8.5 4.2 5.7 5.5 109.1 12.0 97.1 0.3427 8.09 (1.sup.st-layer) Example 14 8.6 6.2 6.6 17.9 90.1 10.4 79.7 0.2810 7.72 (2.sup.nd-layer) Example 14 8.8 6.8 6.1 17.3 71.2 7.9 63.3 0.2397 7.98 (3.sup.rd-layer)

Steam Reforming of Light Hydrocarbons Using the Catalyst of Example 3

[0234] After finalizing the catalyst activation protocol, H.sub.2@100 mL/min is changed to feedstock volumetric flow (12.9 mL/min) and the system pressure is adjusted to 30 Psig in preparation to the start-up of the catalytic test. Then, the feedstock (C1-3 blend) is allowed to enter the system with its respective water flow (Steam/C=5), after 3 minutes the H.sub.2 flow is stopped and a 3-hour period is provided to confirm steady state and flush out any residual reducing gas before GC sampling began. The steam/C ratios are based on the number steam water molecules divided by the number of carbon atoms. That is, the steam/C ration is based on all the carbon atoms in the feedstock. The C from methane is 1, the C from ethane is 2 and the C from propane is 3; thus, in one mole of methane we have one mole of carbon; in a mole of ethane we have 2 moles of carbon and in a mole of propane we have 3 moles of carbon then, the amount of steam is divided by the moles of carbon on each molecule of the feedstock (and its given proportion on it) given a value of 5.

[0235] For this experiment, the temperature was maintained at 500 C.

[0236] To stop the reaction, the following protocol should be followed:

[0237] From reaction temperature, reactor is cooled (e.g., down to 200 C. or below with a ramp of at most 10 C./min) while maintaining reaction feedstock volumetric flow rates (i.e. blend of C1-3 and water). After this temperature is reached, the feedstocks can be stopped (by closing their respective valves and MFC) and the gases are changed to N.sub.2 (or other inert gas at e.g., 30 mL/min) until reaching ambient temperature. Finally, catalyst may be maintained in an inert gas atmosphere, or the unit should be shut down (closing N.sub.2 supply).

Catalyst Reactivity Analysis

[0238] To determine the effectiveness of the catalyst, the reactivity was evaluated in the methane steam reforming reaction which is carried out at 30 psig in a fixed catalytic bed steam reforming reactor 603. The diagram of the experimental setup is illustrated in FIG. 6.

[0239] The experimental apparatus consists of several components.

[0240] The inlet section is configured to feed chemicals into the steam reforming reactor 603 from four sources: a hydrogen source 621, a nitrogen source 622, a hydrocarbon feedstock source 624 and a water source 623. The flow rates of the inlet gases (hydrogen, nitrogen and hydrocarbon blend) are set by three mass flow controllers. The flow rate of steam was controlled through an ISCO Model 500D syringe pump, where water is evaporated through a heating tape around a -inch SS tubing filled with glass beads (steam generator). It will be appreciated that the hydrogen and nitrogen sources may be used when the steam reforming reactor is not in active operation. For example, the hydrogen source may be used when activating the catalyst, and the nitrogen may be used when shutting down the reactor after use.

[0241] The reaction mixture of the hydrocarbon blend and H.sub.2O vapor are premixed in a pre-heater section 627 before introducing them into the reactor at a proper H.sub.2O/CH.sub.4 molar ratio.

[0242] The reaction section consists of a catalytic fixed bed reactor 603 having an up-flow configuration where reactants are feed into the bottom of the reactor and products and unreacted reactants are extracted at the top. In this embodiment, the reactor is heated using heating tapes and the reaction temperature is measured by a multi sensors thermocouple placed at the level of the catalyst. At the outlet of the reactor, a cold trap 626 is used to condense water from the product gas stream which is collected in vessel 625.

[0243] For analysis, the dry outlet gaseous products (H.sub.2, CO, CO.sub.2, non-reacted CH.sub.4 and higher hydrocarbons) are analyzed and quantified by an online gas chromatograph 631 equipped with two thermal conductivity detectors (TCD) and a quadrupole mass spectrometer 632.

[0244] Table 8 shows two examples of feedstock tested in LTMSR at a specific set of reaction conditions. Table 9 shows results obtained using the experimental apparatus described above.

TABLE-US-00008 TABLE 8 Molar Composition of a Typical Natural Gas (Feedstock 1) and a blend of gases typically produced in a refinery (Feedstock 2) Feedstock #1 Feedstock #2 Feedstock (Typical Natural Gas (Typical Gases from Component Composition) Refinery) N.sub.2 0.9 CH.sub.4 93.2 81.0 C.sub.2H.sub.6 5.7 9.5 C.sub.3H.sub.8 0.2 5.7 C.sub.4H.sub.10 3.8

TABLE-US-00009 TABLE 9 a summary of the experimental results obtained in LTMSR with the two feedstocks presented in Table 8 using the catalyst formulation of Example 2 with 3 layers of active phase at 500 C., gas hourly space velocity, GHSV (referred to CH.sub.4-i.e. It is the gas hourly space velocity defined as: CH.sub.4 Gas Flow Rate/Reactor Volume) = 1300 h.sup.1, P = 30 psig and Steam-to-C molar ratio = 14. Feedstock #1 Feedstock #2 Equilibrium CH.sub.4 Conversion* 99.8 98.8 CH.sub.4 Conversion [mole %] 90 83 C.sub.2H.sub.6 Conversion [mole %] 100 100 C.sub.3H.sub.8 Conversion [mole %] 100 100 C.sub.4H.sub.10 Conversion [mole %] N/A 100 Feedstock Gas Flow Rate 80 92 [mL/min] Average Gas Product Flow Rate 324 435 [mL/min] Composition of the Gases at the outlet [mole %] N.sub.2 0.1 Not Applicable CH.sub.4 1.9 3.0 H.sub.2 73.6 71.1 CO 1.6 1.8 CO.sub.2 22.7 24.1 Average Experimental CO.sub.2/CH.sub.4 11.0 8.2 Ratio Theoretical CO.sub.2/CH.sub.4 Ratio 10.3 7.8 Experimental H.sub.2/CO.sub.2 Ratio 3.3 3.1 Theoretical H.sub.2/CO.sub.2 Ratio 3.9 3.7 Carbon Mass Balance Closure 101.2 103.5 [%] H.sub.2 Production [mL/min] 238 309 CO.sub.2 Production [mL/min] 74 105 The Equilibrium calculations were carried out with the Cantera software as implemented in the BIOVIA Materials Studio 2020 package from Dassaul Systemes

[0245] The carbon mass balance closure relates the mols of C entering and leaving a system. Closing atomic mass balances is a critical and necessary step for verifying the performance of any conversion process.

[0246] The Theoretical CO.sub.2/CH.sub.4 and H.sub.2/CO.sub.2 molar ratios presented in the table above have been obtained considering the compositions of the reaction gases (Feedstock #1and Feedstock #2) and assuming no side reactions, thus 100% selectivity toward direct steam reforming products.

[0247] The results shown in Table 9 indicate that the catalyst can achieve near-equilibrium conversion rates (90%) at very mild reaction temperature (i.e.: 500 C.) using a space velocity similar to the values traditionally used in the industry.

[0248] The experimental CO.sub.2/unreacted-CH.sub.4 and H.sub.2/CO.sub.2 molar ratios obtained for both feedstocks are slightly higher from what has been calculated theoretically. The difference in values seems to indicate a slightly higher CO.sub.2 production. This could indicate the presence of one or more side reactions.

[0249] By adjusting the reaction conditions to a lower severity, preferably by increasing the space velocity, which increases hydrogen productivity, the CO.sub.2/unreacted-CH.sub.4 is reduced to the target molar ratio of 1 that allows producing green hydrogen and the required molar proportion of the mixture CO.sub.2-CH.sub.4 to produce carbon nanofibers according to previous art (WO 2020/154799 A1).

Further Experiments

[0250] In the experiments detailed in the sections that follow, four catalytic formulations were evaluated at different space velocities to assess their performance. Additionally, all experiments were conducted using a lower steam/C molar ratio (S/C) of 5, which is a standard value commonly used in commercial steam reforming operations. The reason behind this choice is that, while using an excessive amount of steam beyond the stoichiometric ratio can reduce the risk of thermal cracking of hydrocarbons and coke formation, it also results in substantial operational expenses. Similar to Test #1 and #2, all tests were conducted at a reaction temperature of 500 C., pressure of 30 psig and utilizing Feedstock #1.

[0251] Table #10 shows the results that were obtained using the catalyst formulation of Example 2 with 3 layers of active phase at different GHSV.

TABLE-US-00010 TABLE 10 (Test #3): Summary of the experimental results obtained with the catalyst of Example 2 with 3 layers of active phase: GHSV (h.sup.1) 1300 3000 5000 6500 8000 Equilibrium CH.sub.4 93.5 93.5 93.5 93.5 93.5 Conversion* CH.sub.4 Conversion [mole %] 63 46 44 33 33.0 C.sub.2H.sub.6 Conversion [mole %] 100 100 98.2 79 55.7 C.sub.3H.sub.8 Conversion [mole %] 100 100 100 100 62.3 Feedstock Gas Flow Rate 62.3 143.8 239.7 311.6 383.5 [mL/min] at STP Experimental Average Gas 237.6 463.2 743.16 813.7 955.8 Product Flow Rate [mL/ min] at STP Vol Flow Rate Ratio- 3.8 3.2 3.1 2.6 2.5 Product/Feed Experimental Unreacted ND 0.493 ND 1.155 1.44 Water (g/min) Composition of the Gases at the outlet [mole %] N.sub.2 0.23 0.28 0.29 0.34 0.36 CH.sub.4 8.93 15.68 16.71 23.87 24.96 H.sub.2 71.71 66.47 65.69 59.84 58.55 CO 0.80 0.48 0.38 0.06 0.10 CO.sub.2 18.32 17.09 16.90 15.43 14.98 Ethane 0.00 0.00 0.03 0.46 1.01 Propane 0.00 0.00 0.00 0.00 0.03 CO.sub.2/CH.sub.4 Ratio 2.05 1.09 1.01 0.65 0.60 H.sub.2/CO.sub.2 Ratio 3.91 3.89 3.89 3.88 3.91 *The Equilibrium calculations were carried out with the Cantera software as implemented in the BIOVIA Materials Studio 2020 package from Dassault Systemes.

[0252] At a space velocity of 1300 h.sup.1, a decrease in the steam to carbon ratio from 14 to 5 resulted in a significant drop in the methane conversion rate, from 90% to 63%. This reduction in conversion can be attributed to the limited availability of steam, which slows down the reaction rate and reduces the process efficiency.

[0253] Despite activity reductions at a steam to carbon (S/C) ratio of 5, the methane conversions obtained at space velocities up to 5000 h.sup.1 are still higher than the conversion rate required to achieve a CO.sub.2/unreacted CH.sub.4 ratio at the reactor outlet that is close to the stoichiometric feed ratio needed for dry methane reforming. As previously mentioned in this document, the required methane conversion rate for this specific feedstock with a typical natural gas composition is 40% and the catalyst is capable of achieving the desired conversion rate up to a space velocity of 5000 h.sup.1, indicating that the system is effective at converting methane.

[0254] Additionally, the results demonstrate highly acceptable levels of methane conversion even at significantly increased space velocities of up to 8000 h.sup.1.

[0255] The results also indicated that propane was fully converted at a space velocity of up to 6500 h.sup.1, and ethane was fully converted at a space velocity of up to 5000 h.sup.1, showcasing the high effectiveness of the current catalyst formulation in performing efficiently under a wide range of reaction conditions.

[0256] The selectivity of the process towards direct steam reforming was further confirmed by the results shown in Table #10, which demonstrate full suppression of alternative reactions and nearly 100% selectivity towards direct steam reforming. The low CO production, recorded at a level below 1 mol %, is a remarkable advantage. This outcome can be attributed to the unique properties of the catalyst, which allows for operation at temperatures lower than those commonly used in commercial applications. This reduction in temperature effectively suppresses reverse water-gas shift reactions, reducing the formation of hazardous by-products like CO.

[0257] The carbon balance of the process was also found to be highly satisfactory, with a deviation of approximately 3% in all cases studied.

[0258] Table #11 shows the results that were obtained using the catalyst formulation of Example 2 with 2 layers of active phase, at different GHSV.

TABLE-US-00011 TABLE #11 (Test #4): Summary of the experimental results obtained with the catalyst of Example 2 with 2 layers of active phase. GHSV (h.sup.1) 250 1300 3000 4000 5000 6500 Equilibrium CH.sub.4 93.5 93.5 93.5 93.5 93.5 93.5 Conversion* CH.sub.4 Conversion [mole %] 72 58.5 58.0 57.0 54 50 C.sub.2H.sub.6 Conversion [mole %] 100 100 100 100.0 100 100 C.sub.3H.sub.8 Conversion [mole %] 100 100 100 100.0 100 100 Feedstock Gas Flow 12.8 66.4 153.3 204.4 255.4 332.1 Rate [mL/min] at STP Experimental Average 52.7 242.0 558.3 736.0 887.2 1110.3 Gas Product Flow Rate [mL/min] at STP Vol Flow Rate Ratio - 4.1 3.6 3.6 3.6 3.5 3.3 Product/Feed Experimental Unreacted 0.038 0.220 0.485 Not 0.841 1.145 Water (g/min) Determined Composition of the Gases at the outlet [mole %] N.sub.2 0.22 0.25 0.24 0.25 0.03 0.27 CH.sub.4 6.24 10.48 10.64 11.12 12.21 13.84 H.sub.2 74.16 70.42 70.13 70.57 69.28 67.78 CO 0.48 0.85 1.04 Below 0.73 0.72 Detection Limits CO.sub.2 18.9 18.02 17.95 18.07 17.75 17.40 CO.sub.2/CH.sub.4 Ratio 3.03 1.72 1.69 1.63 1.45 1.26 H.sub.2/CO.sub.2 Ratio 3.9 3.9 3.9 3.9 3.9 3.9

[0259] The catalyst employed in this test exhibits a similar composition in terms of constituent species to that used in previous tests, however, it contains a lower proportion of active phases, Ni, Ce, and Mg, with a reduction of about in their relative amounts.

[0260] This improved performance of the present catalyst is a result of its unique composition, which includes a lower proportion of active phases, Ni, Ce, and Mg, compared to the catalyst used in the previous example. The optimization of the active phase content enhances the catalyst's ability to perform efficiently under a wide range of space velocities. The results show that even with an increase in the space velocity, the conversion rate does not experience a significant drop, reaching 50% even at the highest space velocity of 6500 h.sup.1. Furthermore, the complete conversion of both ethane and propane in all tested space velocity ranges, with a maximum of 6500 h.sup.1, further supports the superiority of the present catalyst formulation. Lastly, the reduction in the proportion of active phases in the formulation offers a more cost-effective solution for the manufacturing process of the catalyst.

[0261] The carbon balance of the process was also found to be highly satisfactory, with a deviation of approximately 3%.

[0262] Table #12 shows the results that were obtained using the catalyst of Example 2 with 1 layer of active phase and different SV.

TABLE-US-00012 TABLE #12 (Test #5): Summary of the experimental results obtained with the catalyst of Example 2 with 1 layer of active phase GHSV (h.sup.1) 250 1300 3000 6500 Equilibrium CH.sub.4 93.5 93.5 93.5 93.5 Conversion* CH.sub.4 Conversion 69 58 51.0 29.5 [mole %] C.sub.2H.sub.6 Conversion 100 100 100 61.2 [mole %] C.sub.3H.sub.8 Conversion 100 100 100 100 [mole %] Feedstock Gas Flow 13.0 67.6 156.0 337.9 Rate [mL/min] at STP Experimental Average 52.4 246.7 528.1 811.3 Gas Product Flow Rate [mL/min] at STP Vol Flow Rate Ratio- 4.0 3.7 3.4 2.4 Product/Feed Experimental Unreacted 0.040 0.226 0.512 1.261 Water (g/min) Composition of the Gases at the outlet [mole %] N.sub.2 0.22 0.25 0.3 0.37 CH.sub.4 7.13 10.66 13.4 27.33 H.sub.2 73.82 70.27 68.1 56.72 CO Not 0.85 0.8 0.07 Applicable CO.sub.2 18.83 17.98 17.5 14.59 Ethane 0.00 0.00 0.0 0.92 CO.sub.2/CH.sub.4 Ratio 2.64 1.69 1.30 0.53 H.sub.2/CO.sub.2 Ratio 3.9 3.9 3.9 3.9 *The Equilibrium calculations were carried out with the Cantera software as implemented in the BIOVIA Materials Studio 2020 package from Dassault Systems

[0263] This alternative catalyst demonstrated potential in its performance, exhibiting a comparable level of methane conversion up to a space velocity of 3000 h1, despite having a lower proportion of active phases in its composition. The decrease in the active phases, Ni, Ce, and Mg, resulted in a reduction in their relative amounts, offering significant economic advantages in terms of catalyst production.

[0264] Despite the lack of testing within the range of 3000 h.sup.1 to 6500 h.sup.1, the available data suggests a decline in activity at higher space velocities. This is inferred from the observed conversion levels of methane and ethane at 6500 h.sup.1, which appear to be reduced. Nevertheless, the catalyst's low active phase concentration still makes it an attractive option for further study and development.

[0265] The carbon balance of the process was also found to be highly satisfactory, with a deviation of approximately 3%.

[0266] Table #13 shows the results that were obtained using the catalyst of Example 5 with 3 layers of active phase and a GHSV=250 h.sup.1.

TABLE-US-00013 TABLE #13 (Test #6): Summary of the experimental results obtained with the catalyst of Example 5 with 3 layers of active phase GHSV (h.sup.1) 250 Equilibrium CH.sub.4 Conversion* 93.5 CH.sub.4 Conversion [mole %] 17 C.sub.2H.sub.6 Conversion [mole %] 50 C.sub.3H.sub.8 Conversion [mole %] 80 C.sub.4H.sub.10 Conversion [mole %] NA Feedstock Gas Flow Rate [mL/min] at STP 12.0 Experimental Average Gas Product Flow Rate 22.7 [mL/min] at STP Vol Flow Rate Ratio-Product/Feed 1.9 Experimental Unreacted Water (g/min) 0.047 Composition of the Gases at the outlet [mole %] N.sub.2 0.48 CH.sub.4 41.13 H.sub.2 45.15 CO NA CO.sub.2 11.71 Ethane 1.52 Propane 0.02 CO.sub.2/CH.sub.4 Ratio 0.28 H.sub.2/CO.sub.2 Ratio 3.86 *The Equilibrium calculations were carried out with the Cantera software as implemented in the BIOVIA Materials Studio 2020 package from Dassault Systemes.

[0267] In the final tested catalyst formulation, the active phases were similar in concentration to those found in the catalyst formulation of Example 2 with 3 layers, however, Nickel was replaced by Cobalt. The results of this single test, performed at a space velocity of 250 h.sup.1, showed lower conversion levels compared to previous tests. The low conversions rate may be attributed to the activation protocol not being optimized for this specific catalyst system.

[0268] Nevertheless, the conversion was still 100% attributed to direct steam reforming, as no secondary reactions were detected.

[0269] The carbon balance of the process was also found to be highly satisfactory, with a deviation of approximately 3%.

Low Temperature Steam Reforming

[0270] To focus on the Low Temperature Steam Reforming aspect of the present disclosure, in another embodiment the Low Temperature Steam Reforming process may be used as a stand-alone process to control, increase and/or maximise the conversion of methane via several reaction chambers aligned in parallel and/or in series.

[0271] In Table 11, it can be seen that a conversion higher than 55% can be achieved with the catalyst described herein (but not exclusively with it) at space velocities as high as 4000 h.sup.1 and in a single pass through the reaction chamber. Reducing the temperature and simplifying of the conventional Steam Methane Reforming (SMR) process (e.g., by eliminating pre-reforming and water gas shift reactors of conventional SMR) means that increasing the amount of catalyst to match the same high productivity of conventional SMR may be feasible with the present technology.

[0272] That is, the catalyst modifications disclosed above to provide a high surface area and good stability enables a high level of conversion, even at lower temperatures. The low energy required to achieve a temperature range of around 500 C. (compared to conventional steam reforming at approximately 900 C.) allows using a conventional electric heating to significantly reduce the direct CO.sub.2 footprint of the process. The lower temperatures used may allow the construction of the reactor to be simplified as the use of high temperature alloy for the hot zones can be reduced or eliminated.

[0273] Due to thermodynamic considerations, Low Temperature Steam Reforming is selectively directed towards H.sub.2 and CO.sub.2, which reduces or eliminates the requirement for a dedicated water-gas shift (WGS) reactor.

[0274] FIG. 7 is a schematic diagram of a Low Temperature Steam Reforming reactor 701. In this embodiment, the reactor comprises multiple reaction chambers, in which steam and hydrocarbons (e.g., including methane) are passed through to produce hydrogen and carbon dioxide. In this case, the multiple reaction chambers comprise a first reaction chamber 741a, a second reaction chamber 741b and a third reaction chamber 741c.

[0275] In this case, all of the multiple reaction chambers are housed within the same heat radiating zone (e.g., an electric oven 744) which heats the reaction chamber to the desired temperature (e.g., in the range 480-520 C.). The pressure within the reaction chambers is 3-10 bars (43-150 psi).

[0276] In this case, the first reaction chamber 741a receives the hydrocarbon feed from the source and water from a water feed.

[0277] In this embodiment, the outlets of each of the reaction chambers are connected to a water separator 742 for separating the water from the other gases exiting the reaction chambers. The water separator may comprise a condenser to condense the steam while the other gases remain in their gaseous state. The separated water may be recycled back to the inlets of the reaction chambers after being reconverted into steam by one or more steam generators 745b. In this case, the reactor comprises a separate feed steam generator 745a for generating steam from the water feed.

[0278] The other gases (including H.sub.2, CO.sub.2, CH.sub.4) are then passed through a gas separator 743 configured to separate out each of the hydrogen and carbon dioxide products and the unreacted methane. The methane stream may comprise trace components of carbon monoxide.

[0279] Subsequent reaction chambers (i.e., second and third reaction chambers in this case) receive hydrocarbons from the recycled separated methane stream and steam from a combination of the water feed and the recycled water.

[0280] In this case, each subsequent reaction chamber is smaller than the last. This allows the Gas Hourly Space Velocity to be the same or similar for each of the reaction chambers (e.g., the GHSV of each reaction chamber within 20% of the mean average across all the reaction chambers within the heat radiating zone).

[0281] The steam/C molar ratio of each subsequent reaction chamber may be the same or higher than the last. In this case, the steam/C molar ratio for the first reaction chamber 741a is around 4, the steam/C molar ratio for the second reaction chamber 741b is around 10, and the steam/C molar ratio for the third reaction chamber 741b is around 15.

[0282] As described above, in this embodiment, the methane stream from the gas separator is recycled to the second and third reaction chambers. This is a simple configuration and can be controlled to provide a specific methane to carbon dioxide ratio (e.g., for dry reforming as described above).

[0283] In this case, the second reaction chamber is larger than the third reaction chamber and the system is configured to divide the separated methane stream between the second and third reaction chambers in a particular ratio.

[0284] In other embodiments, for example where the conversion of methane should be increased or maximized, each subsequent reaction chamber may receive methane from the outlet of the previous reaction chamber in the chain via a dedicated gas separator. For example, in a three-reactor-vessel system, a first gas separator would separate the unreacted methane received from the outlet of the first reaction chamber and deliver the separated methane to the inlet of the second reaction chamber. Then a second gas separator would separate the unreacted methane from the received from the outlet of the second reaction chamber and deliver the separated methane to the inlet of the third reaction chamber. Ensuring gas flow that travels more strictly in series may improve the overall conversion ratio.

[0285] FIG. 8 is a schematic diagram of a Low Temperature Steam Reforming reactor 801 which was used to test experimentally the efficiency of methane conversion. FIG. 8 also shows the molar quantities of reactants and products at various points as they pass though the reactor. The molar quantities may also correspond to rates (e.g., mols/min).

[0286] As in the embodiment of FIG. 7, the reactor comprises multiple reaction chambers (in this case two reaction chambers instead of three), in which steam and hydrocarbons (e.g., including methane) are passed through to produce hydrogen and carbon dioxide. The reactors in this embodiment are a first reaction chamber 841a and a second reaction chamber 841b.

[0287] In this case, all of the multiple reaction chambers 841a,b are housed within the same heat radiating zone (in this case, an electric oven 844) which heats the reaction chambers to the desired temperature. Both reaction chambers 841a,b were operated at a reaction temperature of 500 C. and pressure of 30 psig. The catalyst in both reaction chambers is that described in Example 2 above (two layers of active sites) in both reactors.

[0288] In this case, the first reaction chamber inlet receives the hydrocarbon feed from the source. In this case, the hydrocarbon feed is natural gas (Feedstock #1). Subsequent reaction chamber inlets (i.e., the inlet of the second reaction chamber 841b in this case) receive hydrocarbons from the recycled separated methane stream. It was found that the first reactor converted 58% of the received methane (by molar amount), and the second reactor converted 90% of the received (recycled) methane (by molar amount).

[0289] In this case, the outlets of the reaction chambers have the following compositions: [0290] Molar ratio of first reactor (Product #1): CH.sub.4=39.5 mol, H.sub.2=260.5 mol, CO.sub.2=66.7 mol, and H.sub.2O=397.5 mol. [0291] Molar ratio of second reactor (Product #2): CH.sub.4=3.95 mol, H.sub.2=142.20 mol, CO.sub.2=35.55 mol, and H.sub.2O=481.89 mol.

[0292] These numbers indicate that the amount of methane exiting the second reaction chamber is one tenth of the methane exiting the first reaction chamber.

[0293] The outlets of each of the reaction chambers are connected to a water separator 842 for separating the water from the other gases. The water separator may comprise a condenser to condense the steam. The separated water may be recycled back to the inlets of the reaction chambers after being reconverted into steam by one or more steam generators 845.

[0294] The other gases are then passed through a gas separator 843 configured to separate out each of the hydrogen and carbon dioxide products and the unreacted methane. The methane stream may comprise trace components of carbon monoxide.

[0295] The first reactor was operated at a GHSV of 4000 h.sup.1 and an S/C molar ratio of 5, leading to a conversion of 58%. The second reactor, which receives the remaining unreacted methane from the first reactor, was run at the same space velocity but with a higher S/C molar ratio of 14, resulting in a methane conversion of 90%. The overall molar methane conversion is over 95% (95.8% in this case).

[0296] FIG. 9 is a schematic diagram of a Low Temperature Steam Reforming reactor 901 which was used to test the efficiency of methane conversion using a mathematical simulation. Compared with the experimental set up depicted in FIG. 8, the embodiment of FIG. 9 includes an additional third reactor in series to further convert unreacted methane from the second reactor. That is, this system comprises a first reaction chamber 941a, a second reaction chamber 941b and a third reaction chamber 941c. FIG. 9 also shows the molar quantities of reactants and products at various points as they pass though the reactor. The molar quantities may also correspond to rates (e.g., mols/min).

[0297] The third reaction chamber 941c was also operated under the same conditions as the second. With an initial natural gas inlet rate of 100 mol/min provided to the first reaction chamber and a GHSV of 4000 h.sup.1 for all three reaction chambers, the weight of catalyst used in reactor 1, 2, and 3 was 33.4, 14.0, and 1.4 kg, respectively, indicating a significant reduction in reaction chamber size while progressively converting methane until reaching near-extinction levels. Regarding the molar steam to carbon ratio, the first reaction chamber had a S/C ratio of 5, the second reaction chamber had a steam/C ratio of 14, and the third reactor had a S/C ratio of 14.

[0298] As in the embodiment of FIG. 7, each of the outlets of the three reaction chambers are directed to a water separator 942 which separates the water from the other gases present. This water is recycled back to the reaction chamber inlets via a steam generator 945. Additional water required for the reactions is provided from a make-up water stream.

[0299] The remaining gases are directed to a gas separator 943 which separates the gases into hydrogen, carbon dioxide and methane streams. The methane stream may contain trace quantities of carbon monoxide. The methane stream is recycled to the inlets of the second and third reaction chambers 841b, 841c.

[0300] In this case, the second reaction chamber is larger than the third reaction chamber and the system is configured to divide the separated methane stream between the second and third reaction chambers in a particular ratio. In this case, the ratio is such that the second reactor receives the same quantity of unreacted methane exiting from the first reaction chamber, and the third reaction chamber receives the amount of methane that would be exiting the second reaction chamber if the second and third reaction chamber were arranged in series with a dedicated separator positioned between the second and third reaction chambers. In this case, that corresponds to 39.5 mol of methane going to reaction chamber 2, and 3.95 mol going to reaction chamber 3. Dividing the separated methane in this way between the second and third reaction chambers helps maximize the overall conversion of methane without the need for a dedicated additional separator between the second and third reactor chambers. It will be appreciated that in embodiments with even more reaction chambers, the separated methane may be separated between the reaction chambers in an analogous way to increase overall methane conversion. For example, in steady state operation, the system may be configured and/or controlled such that each subsequent reactor vessel receives a quantity of methane equivalent to the amount of methane emitted by another reaction vessel. E.g., a second reactor may receive the same amount of methane as is emitted by the first, a third reactor may receive the same amount of methane as is emitted by the second, a fourth reactor may receive the same amount of methane as is emitted by the third and so on.

[0301] In this embodiment, the S/C ratio for the second and third reaction chambers is the same. In other embodiments, the S/C ratio of each reaction vessel can be adjusted by changing the quantity of hydrocarbon and/or steam supplied to the inlet or inlets of each reaction chamber.

[0302] In this configuration, the outlets of the reaction chambers were determined to have the following compositions: [0303] Molar ratio of first reactor (Product #1): CH.sub.4=39.5 mol, H.sub.2=260.5 mol, CO.sub.2=66.7 mol, and H.sub.2O=397.5 mol [0304] Molar ratio of second reactor (Product #2): CH.sub.4=3.95 mol, H.sub.2=142.20 mol, CO.sub.2=35.55 mol, and H.sub.2O=481.89 mol. [0305] Molar ratio of third reactor (Product #3): CH.sub.4=0.40 mol, H.sub.2=14.22 mol, CO.sub.2=3.55 mol, and H.sub.2O=48.19 mol.

[0306] The results demonstrate that by combining the three reactors, a global methane conversion greater than 99% can be achieved (99.6% in this simulation).

[0307] As described above, this Low Temperature Steam Reforming reactor can be used to increase or maximise the conversion of methane. In other configurations, these reactors (or reactors with a single reaction chamber) can be configured to reduce the conversion of methane such that a proportion of the methane can pass through the reactor in an unreacted state. The reaction may be controlled such that the number ratio between the produced carbon dioxide to the unreacted methane exiting the reactor is between 0.9 and 1.1.

[0308] The reactor may be combined with a dry reforming of methane (DRM) reactor to produce an output of syngas where the number ratio between carbon monoxide and hydrogen is around 1 (e.g., between 0.9 and 1.1).

[0309] This proportion may be adjusted with available hydrogen from the steam reforming to produce the desired proportion to manufacture products such as graphite, carbon nanofiber, methanol or any other one carbon block petrochemical such as formic acid or formaldehyde. Longer chain carbon hydrocarbons may also be produced using the syngas.

Other Considerations

[0310] The support where the active metal (or metals) is incorporated plays an important role on the dispersion by providing a high surface area but also can provide some properties like basicity, oxygen storage and reducibility which can have implications for their resistance against carbon formation.

[0311] Promoters are also implemented to develop a reforming catalyst and there are two main types of promoters; one is responsible for modifying the textural or structural properties and the other one modifies the chemical or electronic properties. To avoid completely, or at least to delay for some long time the sintering of the active species, textural promoters are typically employed to enhance the textural properties of the catalyst. On the other hand, chemical promoters help to moderate the formation of carbon and oxidize carbonaceous species by providing additional new active sites or enhancing the chemical property relating to the reactivity of the catalyst by modifying the basicity or redox properties in general.

[0312] Suitable preparation methods as well as activation protocols must be designed and developed as the employed preparation and activation methods strongly influence the physicochemical and catalytic performance of the reforming catalyst. Thus, suitable and proper preparation methods are able to produce better dispersion of the active phases, gives stronger metal-support interaction and high surface areas. All of these are responsible for the desired high activity, stability and resistance against sintering and carbon formation. An optimized preparation method can strengthen the distinct ability of the support. The activation protocol, to make the catalyst active for reforming, has a significant role in the formation of the active species and how the atoms organize themselves, thereby influencing the catalytic performance. It is well-known that a bad activation is responsible for the unsuccessful performance of a very promising catalyst.

[0313] Although the present present disclosure has been described and illustrated with respect to preferred embodiments and preferred uses thereof, it is not to be so limited since modifications and changes can be made therein which are within the full, intended scope of the present disclosure as understood by those skilled in the art.

BIBLIOGRAPHY

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