CN117732474A - Methane steam reforming catalyst, preparation method thereof and method for preparing hydrogen by methane steam reforming - Google Patents
Methane steam reforming catalyst, preparation method thereof and method for preparing hydrogen by methane steam reforming Download PDFInfo
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- CN117732474A CN117732474A CN202211121698.3A CN202211121698A CN117732474A CN 117732474 A CN117732474 A CN 117732474A CN 202211121698 A CN202211121698 A CN 202211121698A CN 117732474 A CN117732474 A CN 117732474A
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- 239000003054 catalyst Substances 0.000 title claims abstract description 178
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title claims abstract description 160
- 239000001257 hydrogen Substances 0.000 title claims abstract description 65
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 65
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 60
- 238000000629 steam reforming Methods 0.000 title claims abstract description 47
- 238000000034 method Methods 0.000 title claims abstract description 46
- 238000002360 preparation method Methods 0.000 title claims abstract description 28
- 229910052751 metal Inorganic materials 0.000 claims abstract description 95
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- GDSRMADSINPKSL-HSEONFRVSA-N gamma-cyclodextrin Chemical compound OC[C@H]([C@H]([C@@H]([C@H]1O)O)O[C@H]2O[C@@H]([C@@H](O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O3)[C@H](O)[C@H]2O)CO)O[C@@H]1O[C@H]1[C@H](O)[C@@H](O)[C@@H]3O[C@@H]1CO GDSRMADSINPKSL-HSEONFRVSA-N 0.000 claims description 7
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- 229910052772 Samarium Inorganic materials 0.000 claims description 4
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 4
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- HFHDHCJBZVLPGP-RWMJIURBSA-N alpha-cyclodextrin Chemical compound OC[C@H]([C@H]([C@@H]([C@H]1O)O)O[C@H]2O[C@@H]([C@@H](O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O[C@H]3O[C@H](CO)[C@H]([C@@H]([C@H]3O)O)O3)[C@H](O)[C@H]2O)CO)O[C@@H]1O[C@H]1[C@H](O)[C@@H](O)[C@@H]3O[C@@H]1CO HFHDHCJBZVLPGP-RWMJIURBSA-N 0.000 claims description 2
- 229940043377 alpha-cyclodextrin Drugs 0.000 claims description 2
- 238000001354 calcination Methods 0.000 claims description 2
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 2
- 239000011261 inert gas Substances 0.000 claims description 2
- 229940032147 starch Drugs 0.000 claims description 2
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- 230000009286 beneficial effect Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 238000005245 sintering Methods 0.000 description 7
- 238000010521 absorption reaction Methods 0.000 description 6
- 238000002407 reforming Methods 0.000 description 6
- 239000003345 natural gas Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
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- 229910021641 deionized water Inorganic materials 0.000 description 4
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- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
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- 230000003197 catalytic effect Effects 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- KBJMLQFLOWQJNF-UHFFFAOYSA-N nickel(ii) nitrate Chemical compound [Ni+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O KBJMLQFLOWQJNF-UHFFFAOYSA-N 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
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- 229910052747 lanthanoid Inorganic materials 0.000 description 2
- 150000002602 lanthanoids Chemical class 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- MQRWBMAEBQOWAF-UHFFFAOYSA-N acetic acid;nickel Chemical compound [Ni].CC(O)=O.CC(O)=O MQRWBMAEBQOWAF-UHFFFAOYSA-N 0.000 description 1
- 238000007605 air drying Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000004517 catalytic hydrocracking Methods 0.000 description 1
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- 229940078494 nickel acetate Drugs 0.000 description 1
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- 229920006395 saturated elastomer Polymers 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 description 1
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- 230000002195 synergetic effect Effects 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
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- Catalysts (AREA)
Abstract
The invention relates to the field of catalysts, and discloses a methane steam reforming catalyst, a preparation method thereof and a method for preparing hydrogen by methane steam reforming, wherein the catalyst comprises a carrier, an active metal component and an auxiliary agent component which are loaded on the carrier; wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; wherein the average grain size of the active metal component is 3-12nm, the content of the carrier is 72-94wt% based on the total amount of the catalyst, the content of the active metal component is 5.9-18wt% based on oxide, and the content of the auxiliary component is 0.1-10wt%. The catalyst has higher metal dosage and smaller active metal component grain size, so that the catalyst has higher reactivity and anti-carbon property, and the finished catalyst is stable and continuous for 2000 hours under laboratory conditions without deactivation, thereby having feasibility of industrial application.
Description
Technical Field
The invention relates to the field of catalysts, in particular to a methane steam reforming catalyst, a preparation method thereof and a method for preparing hydrogen by methane steam reforming.
Background
In the chemical industry, the largest amount of hydrogen is synthesized by ammonia and petroleum refining, and hydrogen is needed in other fields such as metallurgy, electronics, glass, medicine, food, aerospace, energy sources and the like. On the one hand, in recent years, with the increase of hydrogen demand for hydrogen reforming and hydrocracking reactions in oil refining and the trend of increasing demand for hydrogen in petrochemical industries such as synthetic ammonia, synthetic gasoline, synthetic methanol, fischer-tropsch synthesis and the like, technologies for steam reforming of methane, naphtha and heavy oil and hydrogen production by coal gasification are receiving more attention. In particular, social importance is increasing on environmental quality, sulfur content indexes in gas emissions are reduced, and meanwhile, the processing degree of crude oil is continuously deepened, which also increases the demand for hydrogen. On the other hand, hydrogen is a clean fuel with large combustion heat valueWhile the product is water, without generating a large amount of greenhouse gases such as CO 2 And contaminating gases, e.g. SO x 、NO x Etc., and therefore, there is an increasing demand for clean fuels.
Natural gas, because of its abundance, will be the primary feedstock for the production of synthesis gas and thus hydrogen. Although coal reserves are larger and cheaper, it costs three times as much investment as a natural gas-fed synthesis gas plant. Thus, the natural gas reforming hydrogen production process will still be the most dominant hydrogen production route worldwide in the future.
At present, the natural gas hydrogen production process is very mature, but the main disadvantage is high energy consumption, which leads to significant increase of the production cost of hydrogen. To reduce the energy consumption of the process, reducing the water to carbon ratio is a viable path. Attempts have been made in this field by various large hydrogen production technology companies abroad, such as the bronzing process in the united states, the AMV process of ICI company, the LCA process, and the like. To meet the requirements of the new process, efficient catalysts corresponding to the requirements must be developed. In addition to the various properties of the conventional natural gas steam reforming catalyst, the catalyst must also have higher activity and stronger carbon deposit resistance so as to be capable of continuous and stable operation for a long period at a low water-to-carbon ratio.
The energy-saving catalyst for preparing hydrogen by steam reforming of methane, which is developed at home and abroad, is mostly prepared by an impregnation method, while the commonly used catalyst carrier for preparing hydrogen is mostly prepared by adopting an alpha-Al high-temperature sintering method 2 O 3 、CaO-Al 2 O 3 Or MgO-Al 2 O 3 . The high-temperature sintering type carrier has high strength but low water absorption, and when the high-temperature sintering type carrier is used for loading active metals by an impregnation method, a high-concentration nickel nitrate solution needs to be prepared, the solution needs to be heated, and the required metal loading amount can be achieved by generally impregnating the high-temperature sintering type carrier twice or three times.
Disclosure of Invention
The invention aims to solve the problems of large grain size, low catalyst activity, poor anti-carbon deposition performance and long preparation flow of active metal components in catalysts in the prior art, and provides a methane steam reforming catalyst, a preparation method thereof and a method for preparing hydrogen by methane steam reforming.
In order to achieve the above object, a first aspect of the present invention provides a steam methane reforming catalyst comprising a carrier and an active metal component and an auxiliary component supported on the carrier; wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; wherein the average particle diameter of the active metal component is 3-12nm, the content of the carrier is 72-94wt% based on the total amount of the catalyst, the content of the active metal component is 5.9-18wt% based on oxide, and the content of the auxiliary component is 0.1-10wt%.
In a second aspect, the present invention provides a method for preparing a steam methane reforming catalyst, the method comprising: contacting the carrier loaded with the organic adsorbent with impregnating solution, and then performing first drying and roasting;
the impregnating solution contains a soluble compound of an active metal component and a soluble compound of an auxiliary component, wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; the carrier and the impregnating solution are used in amounts such that the catalyst is obtained, the carrier content is 81-91wt%, the active metal component content is 5.9-18wt% and the auxiliary component content is 0.1-10wt% in terms of oxide.
In a third aspect, the present invention provides a steam methane reforming catalyst prepared by the above-described preparation method.
In a fourth aspect, the invention provides a method of producing hydrogen by steam reforming methane, the method comprising: contacting methane and water with a catalyst under conditions for steam reforming of methane to produce hydrogen, the catalyst being a steam reforming catalyst for methane as provided in the first or third aspect.
The inventors found in the research that, in the prior art, in order to pursue the target high loading, the concentration of the impregnating solution is often required to be high, and the impregnating solution is required to be subjected to multiple times of roasting, so that the crystal grains of the active metal component are too large, and the activity of the catalyst is difficult to reach the expected level, therefore, the catalyst in the prior art has difficulty in combining the higher metal loading and the smaller crystal grain size of the active metal component. The methane steam reforming catalyst provided by the invention can give consideration to higher metal dosage and smaller grain size of active metal components, so that the catalyst has higher reactivity and anti-carbon performance, and the finished catalyst is continuous and stable to run for 2000 hours under laboratory conditions without deactivation, thus having feasibility of industrial application; meanwhile, the catalyst preparation method provided by the invention has simple production flow, and can meet the requirement of the target active metal component on the amount by one-step impregnation, so that the crystal grain size of NiO in the obtained catalyst is ensured to be small, the operation is convenient, and the catalyst production cost is greatly saved.
Drawings
FIG. 1 is XRD patterns of the catalysts obtained in example 1 and comparative example 1;
FIG. 2 shows the results of evaluation of the long-period reaction stability of the catalyst obtained in example 1.
Detailed Description
The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein.
The first aspect of the invention provides a methane steam reforming catalyst comprising a support and an active metal component and an adjunct component supported on the support; wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; wherein the average grain size of the active metal component is 3-12nm, the content of the carrier is 72-94wt% based on the total amount of the catalyst, the content of the active metal component is 5.9-18wt% based on oxide, and the content of the auxiliary component is 0.1-10wt%.
Compared with the methane steam reforming catalyst in the prior art, the active metal component in the catalyst has smaller grain size, so that the catalyst has higher reactivity and anti-carbon performance, and the finished catalyst is stable and continuous for 2000 hours under laboratory conditions without deactivation and has feasibility of industrial application.
According to the present invention, it is preferable that the average grain size of the active metal component is 4 to 9nm. In the above preferred cases, it is advantageous to improve the catalyst activity and the anti-coking property.
In the present invention, the average grain size of the active metal component can be measured by XRD and calculated according to the Scherrer's formula.
According to the present invention, it is preferable that the content of the carrier is 81 to 91wt% based on the total amount of the catalyst, the content of the active metal component is 8 to 14wt% based on the oxide, and the content of the auxiliary component is 1 to 5wt%. With the above preferred composition, further improvement in the activity and stability of the catalyst is facilitated.
It is understood that when the catalyst contains only the carrier, the active metal component and the auxiliary component, the total content of the carrier, the active metal component and the auxiliary component is added up to satisfy 100%.
In the invention, the content of each component is measured by adopting a fluorescence analysis method.
In the present invention, the carrier may be selected as usual in the art, and may be obtained commercially or by using a preparation method well known in the art. For example, the carrier may be an oxide carrier prepared by a high temperature sintering method, preferably the carrier may be alpha-Al 2 O 3 、MgO-Al 2 O 3 、CaO-Al 2 O 3 At least one of SiC and BN, more preferably alpha-Al 2 O 3 . When alpha-Al is used 2 O 3 Is more beneficial to improving the catalytic reaction activity and the anti-carbon property of the catalyst when being a carrier.
Preferably, the water absorption of the carrier is 0.18-0.25%.
The inventors found in the study that, for a high-temperature sintered carrier, since the water absorption rate of the carrier is relatively low, multiple impregnations are required to ensure the metal loading to reach the target, and after the active metal component is loaded by adopting a conventional impregnation method, the average particle size of the active metal component is larger, so that the catalyst activity is low and the anti-carbon deposition performance is poor. The catalyst provided by the invention still has proper grain size of the active metal component when adopting a high-temperature sintering type carrier, and is beneficial to improving the catalytic activity of the catalyst.
In the present invention, the rare earth metal refers to lanthanoid of group IIIB of the periodic table of elements and scandium and yttrium chemically similar to lanthanoid, and a total of 17 elements. Preferably, the auxiliary component is selected from at least one of La, ce, pr and Sm, preferably La and/or Ce. The adoption of the auxiliary component is beneficial to improving the dispersibility and the carbon deposit resistance of the active metal.
According to the present invention, preferably, the molar ratio of the auxiliary component and the active metal component is 0.03 to 0.2 in terms of elements: 1, preferably 0.04-0.15:1. in the above preferred case, the catalyst activity and stability are enhanced by the cooperation of the auxiliary component and the active metal component.
In a second aspect, the present invention provides a method for preparing a steam methane reforming catalyst, the method comprising: contacting the carrier loaded with the organic adsorbent with impregnating solution, and then performing first drying and roasting;
the impregnating solution contains a soluble compound of an active metal component and a soluble compound of an auxiliary component, wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; the carrier and the impregnating solution are used in amounts such that the catalyst is produced, the carrier content is 72-94wt%, the active metal component content is 5.9-18wt% and the auxiliary component content is 0.1-10wt% in terms of oxide.
In the prior art, the catalyst for preparing hydrogen by methane steam reforming is prepared by an impregnation method, and due to the influence of water absorption of a carrier, multiple impregnations or higher concentration of impregnating solution are often needed, so that the grain size of an active metal component is increased, the activity is limited, and the preparation process is increased, so that the production cost of the catalyst is increased. The inventor of the invention discovers in the research that the organic adsorbent pre-adsorbed on the surface of the carrier can be utilized to strengthen the adsorption of the active metal component and the auxiliary component on the surface of the carrier, can realize the high-efficiency load of the active metal component and the auxiliary component under the condition of lower concentration of the impregnating solution, is beneficial to reducing the grain size of the active metal component and improving the catalytic activity and stability of the catalyst.
According to the present invention, it is preferable that the organic adsorbent-supporting carrier and the impregnation liquid are used in such amounts that the carrier is contained in an amount of 81 to 91wt% based on the total amount of the catalyst to be produced, the active metal component is contained in an amount of 8 to 14wt% based on the oxide, and the auxiliary component is contained in an amount of 1 to 5wt%. With the above preferred composition, further catalyst activity and stability are favored.
According to the present invention, preferably, the soluble compounds of the auxiliary component and the soluble compounds of the active metal component are used in a molar ratio of 0.03 to 0.2 in terms of elements: 1, preferably 0.04-0.15:1, a step of; within the above preferred molar ratio ranges, the catalyst activity and stability are facilitated by the co-action of the adjunct component and the active metal component.
In the present invention, the support may be selected conventionally in the art, for example, may be an oxide support prepared by a high temperature sintering method, for example, the support may be α -Al 2 O 3 、MgO-Al 2 O 3 、CaO-Al 2 O 3 At least one of SiC and BN, preferably alpha-Al 2 O 3 . When alpha-Al is used 2 O 3 Is more beneficial to improving the catalytic reaction activity and the anti-carbon property of the catalyst when being a carrier.
In the present invention, preferably, the carrier is a carrier after molding, and the molding may be a molding method conventional in the art, such as extrusion molding or compression molding.
In the present invention, preferably, the auxiliary component is selected from at least one of La, ce, pr and Sm, preferably La and/or Ce. The auxiliary component is beneficial to improving the activity and the anti-carbon performance of the catalyst, and meanwhile, the auxiliary component and the active metal component are synergistic, so that the further growth of the active metal component grains is inhibited.
The types of soluble compounds of the active metal component according to the invention are well known to the person skilled in the art and may be routine choices in the art. For example, the soluble compound of the active metal component is selected from at least one of nickel nitrate and/or nickel acetate; further preferred is nickel nitrate.
According to the present invention, preferably, the concentration of the soluble compound of the active metal component in the impregnation liquid is 0.5 to 2.5g/mL, further preferably 0.8 to 1.5g/mL; in the concentration range, the grain size of the active metal component is further reduced, and the activity and the carbon deposit resistance of the catalyst are improved.
The types of soluble compounds of the auxiliary component according to the invention are well known to the person skilled in the art and may be routine choice in the art. For example, the soluble compound of the adjunct component is selected from at least one of the group consisting of nitrate, chloride and acetate of a metal; further preferred is nitrate.
In the present invention, the soluble compounds of the active metal component and the auxiliary component may each carry water of crystallization, which is well known to those skilled in the art and will not be described herein.
In the present invention, the contacting of the organic adsorbent-laden carrier with the impregnating liquid may be carried out using procedures conventional in the art, such as an isovolumetric impregnation method or a supersaturation impregnation method, preferably the contacting includes: the carrier loaded with the organic adsorbent is immersed in the immersion liquid to be contacted. Preferably, the impregnation is carried out only once in the preparation process until adsorption saturation. The adsorption saturation can be judged according to an adsorption rate curve obtained in a laboratory, and the adsorption saturation can be judged after soaking for a certain time without obvious change of the adsorption quantity.
According to the present invention, the conditions of the contact may be adjusted according to actual needs as long as the above adsorption saturation can be achieved. Preferably, the contact time is 10-60min, preferably 20-35min.
In the present invention, preferably, the preparation method includes only one time of the contacting process. That is, the requirement of the target active metal component and the auxiliary component on the upper amount can be met through one-step impregnation, so that the growth of crystal grains of the active metal component caused by multiple impregnations (including drying and roasting) is avoided.
In the present invention, the first drying and firing may be performed using the operations and conditions conventional in the art, and the present invention is not particularly limited thereto. Preferably, the first drying conditions include: the drying temperature is 60-140 ℃, preferably 70-110 ℃; the drying time is 1-6 hours, preferably 2-4 hours.
Preferably, the roasting conditions include: the roasting temperature is 300-800 ℃, preferably 400-550 ℃; the calcination time is 1 to 5 hours, preferably 2 to 4 hours.
According to the present invention, preferably, the organic adsorbent is selected from at least one of starch, glucose, α -cyclodextrin, β -cyclodextrin, γ -cyclodextrin and maltosaccharin; preferably at least one selected from glucose, beta-cyclodextrin and gamma-cyclodextrin; further preferred are beta-cyclodextrin and/or gamma-cyclodextrin; the adoption of the preferable organic adsorbent is beneficial to promoting the effective adsorption of the active metal component and the auxiliary component and improving the metal loading in the primary impregnation process.
According to the present invention, the content of the organic adsorbent is preferably 0.05 to 3wt%, more preferably 0.2 to 1.5wt%, based on the total amount of the organic adsorbent-supporting carrier. At the above preferred loadings, it is helpful to regulate the appropriate loadings of active metal and promoter metal.
According to the present invention, preferably, the organic adsorbent-supporting carrier is obtained by the following method: the solution containing the organic adsorbent is contacted with the support, followed by pre-dewatering and secondary drying.
In the present invention, the "first drying" and "second drying" do not refer to an operation sequence, and are only used to distinguish between drying modes and conditions in different steps.
The contacting may be carried out in a manner conventional in the art, for example by immersing or spraying the solution containing the organic adsorbent in contact with the support.
According to the invention, the solution also contains a solvent, preferably water.
Preferably, the concentration of the organic adsorbent-containing solution is 0.005 to 0.1g/mL, and more preferably 0.009 to 0.07g/mL.
According to the present invention, preferably, the pre-dewatering comprises: pre-dewatering the product obtained by contact in the presence of warm air until no surface water is present; for example, the product of the contact may be placed on a vibrating screen and then warm air is introduced until the surface is free of clear water.
Preferably, the temperature of the warm air is 30-80 ℃, preferably 35-60 ℃.
According to the invention, preferably, the second drying temperature does not exceed 100 ℃. Too high a second drying temperature may cause the structure of the organic adsorbent to be broken, thereby affecting its adsorption effect on the active metal component and the auxiliary component.
In the invention, there is no specific requirement on the time of the second drying, as long as the contact product is thoroughly dried, and it is understood that the contact product is thoroughly dried when the quality of the contact product is no longer significantly changed. For example, the second drying time may be 2 to 20 hours.
According to the present invention, preferably, the second drying means is at least one selected from the group consisting of freeze drying, low temperature vacuum drying and low temperature hot air drying, and is preferably freeze drying.
Preferably, the conditions of freeze-drying include: the temperature is-30 ℃ to-5 ℃, preferably-25 ℃ to-15 ℃; the drying time is 1-10h.
Preferably, the conditions of the low-temperature vacuum drying include: vacuum degree is-0.09 MPa to-0.05 MPa, preferably-0.09 MPa to-0.07 MPa; the temperature is 30-70deg.C, preferably 40-60deg.C; the drying time is 2-10h.
Preferably, the conditions of the low-temperature hot air drying include: the flow rate of the hot air is 0.1 to 0.5m/s, preferably 0.2 to 0.4m/s; the temperature is 40-80deg.C, preferably 50-70deg.C; the drying time is 2-10h.
The adoption of the preferable second drying mode is favorable for the structural stability of the organic adsorbent, further improves the metal loading and improves the catalytic activity and the carbon deposition resistance of the catalyst.
In a third aspect, the present invention provides a steam methane reforming catalyst prepared by the above-described preparation method.
In a fourth aspect, the invention provides a method of producing hydrogen by steam reforming methane, the method comprising: contacting methane and water with a catalyst under conditions for steam reforming of methane to produce hydrogen, wherein the catalyst is a steam reforming catalyst for methane as provided in the first and third aspects above.
The methane steam reforming catalyst provided by the invention is used for methane steam reforming hydrogen production, and can obtain higher methane conversion rate under lower water-carbon ratio.
The method of contacting methane and water with the catalyst is not particularly limited and may be a conventional choice in the art, and preferably the contacting is performed in a fixed bed reactor.
Preferably, the conditions for steam reforming methane to produce hydrogen include: the volume ratio of water to methane is (1.2-5): 1, preferably (2.5-3.5): 1, a step of; the reaction temperature is 600-900 ℃, preferably 650-850 ℃; the pressure is 0-4MPa, preferably 1.5-3.5MPa; methane carbon space velocity of 400-5000h -1 Preferably 600-4000h -1 . In the invention, the pressure is gauge pressure, and the methane carbon space velocity is volume space velocity.
According to the present invention, preferably, the method further comprises: before the reaction, the catalyst is subjected to reduction activation under a hydrogen-containing atmosphere.
Preferably, the conditions of the reductive activation include: the reduction temperature is 300-800 ℃, preferably 400-600 ℃; the reduction time is 0.5 to 10 hours, preferably 1 to 5 hours, further preferably 2 to 4 hours; the reduction pressure is 0 to 2MPa, preferably 0 to 1MPa, more preferably 0 to 0.5MPa.
According to the present invention, preferably, the hydrogen-containing atmosphere is hydrogen or a mixed gas of hydrogen and an inert gas; for example, the mixture may be a mixture of hydrogen and nitrogen and/or argon. Preferably, the volume content of hydrogen in the mixture is 10-80%, more preferably 20-60%.
The present invention will be described in detail by examples.
In the examples below, each of the reaction starting materials was obtained from commercial sources unless otherwise specified.
In the following examples, the content of each component in the catalyst was measured by fluorescence analysis.
The average grain size of the active metal component was tested using XRD method and calculated according to Scherrer's formula.
On-line sampling analysis by gas chromatography to calculate the tail gas composition, methane conversion (X CH4 ) Calculated by the following formula:
wherein C is CH4 Is the volume concentration of methane, C N2 Is the volume concentration of nitrogen.
Example 1
(1) Preparation of the catalyst
Weighing 100g of molded high-temperature alpha-Al 2 O 3 The carrier is ready for use, and the water absorption rate of the carrier is 0.21%. Weighing 0.8g of beta-cyclodextrin, pouring the beta-cyclodextrin into deionized water, fixing the volume to 21mL, and fully stirring and dissolving; the solution is then sprayed to the shaped high temperature alpha-Al 2 O 3 On the carrier, mixing uniformly. Then placing the mixture on a vibrating screen, and drying the mixture by warm air at 40 ℃ until no surface water exists; and then performing secondary drying by adopting a freeze drying mode, and fully drying for 10 hours at the temperature of minus 20 ℃ to obtain the carrier loaded with the organic adsorbent. The content of the organic adsorbent was 0.79wt% based on the total amount of the organic adsorbent-supporting carrier.
21g of Ni (NO) was weighed out 3 ) 2 ·6H 2 O and 3.6g La (NO) 3 ) 2 ·9H 2 O was dissolved in 15mL deionized water and stirred at room temperature. Immersing 10g of the carrier loaded with the organic adsorbent into the prepared impregnating solution, standing for 30 minutes, and then removing the carrier with saturated adsorptionTaking out the impregnating solution, draining off water, and putting the impregnating solution into an oven to be dried for 3 hours at 80 ℃; and (3) placing the dried sample into a muffle furnace, and roasting at 500 ℃ for 2 hours to obtain the required catalyst for producing hydrogen by reforming methane steam. The fluorescence analysis result shows that the NiO content in the catalyst is 12.6wt%, la 2 O 3 The content of (2.3 wt.%) and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.084:1.
the XRD pattern of the catalyst obtained in example 1 is shown in FIG. 1, and the crystal grain size of NiO was calculated to be 5.6nm from the diffraction half-width of NiO in the pattern.
(2) Activity evaluation
0.2g of the catalyst obtained in example 1 was weighed and charged into a fixed bed reactor, and reduction and activation were carried out under normal pressure at 550℃for 3 hours in a pure hydrogen atmosphere. After the reduction is finished, heating to 700 ℃ in a hydrogen atmosphere, and switching raw material gas to react, wherein the volume ratio of water to methane in the raw material gas is 2:1, methane carbon space velocity of 4000h -1 The reaction pressure is normal pressure. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 89.7%.
The catalyst obtained was subjected to reaction conditions simulating industrial applications at an inlet temperature of 600 ℃, an outlet temperature of 810 ℃ and a water/methane volume ratio of 2.8:1, methane carbon space velocity 1500h -1 The results of the long-period reaction stability evaluation at a reaction pressure of 2.5MPa are shown in FIG. 2. As can be seen from fig. 2, the reaction performance of the catalyst is very stable.
Example 2
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that the organic adsorbent was gamma-cyclodextrin, to obtain the desired catalyst for steam reforming of methane to produce hydrogen. The fluorescence analysis result shows that the NiO content in the catalyst is 11.3wt percent, la 2 O 3 The content of (2) is 2wt%, and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.081:1.
XRD analysis showed that the crystal grain size of NiO in the catalyst was 7.6nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 86.5%.
Example 3
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that the second drying in the loaded organic adsorbent was carried out at 50℃for 3 hours under vacuum, with a vacuum of-0.09 MPa; the catalyst for producing hydrogen by reforming methane with steam is obtained. The fluorescence analysis result shows that the NiO content in the catalyst is 11.9wt percent, la 2 O 3 The content of (2.1 wt.%) and the balance of carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.081:1.
XRD analysis showed that the crystal grain size of NiO in the catalyst was 7.1nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 87.9%.
Example 4
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1 except that the amount of beta-cyclodextrin was 1.2g, and the content of the organic adsorbent was 1.2% by weight based on the total amount of the organic adsorbent-supporting carrier.
The catalyst for producing hydrogen by reforming methane with steam is obtained. The fluorescence analysis result shows that the NiO content in the catalyst is 13.5wt percent, la 2 O 3 The content of (2.7 wt.%) and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.092:1.XRD analysis showed that the crystal grain size of NiO in the catalyst was 6.9nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 87.6%.
Example 5
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1 except that the amount of beta-cyclodextrin was weighed to be 0.17g, and the content of the organic adsorbent was 0.17% by weight based on the total amount of the organic adsorbent-supporting carrier.
The catalyst for producing hydrogen by reforming methane with steam is obtained. The fluorescence analysis result shows that the concentration of NiO in the catalyst is 7.4wt percent, la 2 O 3 The content of (2) is 1.3wt%, and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.081:1.XRD analysis showed that the crystal grain size of NiO in the catalyst was 4.6nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 78.5%.
Example 6
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that 27g of Ni (NO 3 ) 2 ·6H 2 O and 4.62g La (NO) 3 ) 2 ·9H 2 O is dissolved in 15mL deionized water to obtain the required catalyst for producing hydrogen by steam reforming of methane. The fluorescence analysis result shows that the concentration of NiO in the catalyst is 14.7 and wt percent, la 2 O 3 The content of (2.7 wt.%) and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.084:1.
XRD analysis showed that the crystal grain size of NiO in the catalyst was 7.4nm.
As can be seen from a comparison of example 1 and example 6, when the concentration of the soluble compound of the active metal component in the impregnation liquid is too high, the size of NiO crystal grains supported on the support is increased.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 88.5%.
Example 7
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that 21g of Ni (NO 3 ) 2 ·6H 2 O and 1.2g La (NO) 3 ) 2 ·9H 2 O is dissolved in 15mL deionized water to obtain the required catalyst for producing hydrogen by steam reforming of methane. The fluorescence analysis result shows that the concentration of NiO in the catalyst is 12.2wt percent, la 2 O 3 The content of (2) is 0.98wt%, and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.03:1.
XRD analysis showed that the crystal grain size of NiO in the catalyst was 5.3nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 86.5%.
Example 8
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that the second drying mode in the pre-adsorbed organic adsorbent was ordinary hot air drying at 120℃for 3 hours. The fluorescence analysis result shows that the NiO content in the catalyst is 9.2wt percent, la 2 O 3 The content of (2) was 1.7wt%, the balance being carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.085:1.
the loading of both the active component and the auxiliary component is greatly reduced, which means that the high-temperature air drying affects the structure of the organic adsorbent, and the selective cation adsorption capacity of the organic adsorbent is poor. XRD analysis showed that the crystal grain size of NiO in the catalyst was 6.6nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 75.6%.
Example 9
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that the support was MgO-Al calcined at a high temperature 2 O 3 The water absorption rate of the composite oxide is 0.22%, and the catalyst for preparing hydrogen by reforming methane steam is obtained. The fluorescence analysis result shows that the NiO content in the catalyst is 13.1wt percent, la 2 O 3 The content of (2.5 wt.%) and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.087:1.
XRD analysis showed that the crystal grain size of NiO in the catalyst was 6.4nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 86.1%.
Example 10
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that the organic adsorbent was starch, to obtain the desired catalyst for steam reforming of methane to produce hydrogen. The fluorescence analysis result shows that the NiO content in the catalyst is 10.9wt percent, la 2 O 3 The content of (2) is 1.8wt%, and the rest is carrier. In the catalyst, the auxiliary agent comprises the following components in terms of elements: the molar ratio of active metal component was about 0.076:1.
XRD analysis showed that the crystal grain size of NiO in the catalyst was 5.2nm.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 84.3%.
Comparative example 1
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that the organic adsorbent was not adsorbed on the surface of the support in advance. At this time, the adsorption capacity of the carrier is poor, the requirement of the active metal on the amount can be met only by dipping twice, and the fluorescence analysis result shows that the NiO content after one dipping is 6.7 percent, la 2 O 3 The content of (2) is 1.2wt%, and the rest is carrier. The NiO content in the catalyst after the two times of impregnation is 11.5wt percent, la 2 O 3 The content of (2.2 wt.%) and the rest is carrier. The XRD spectrum of the obtained catalyst is shown in FIG. 1, and the crystal grain size of NiO is calculated to be 13.7nm from the diffraction half-width of NiO in the spectrum. It can also be seen from a comparison of the XRD patterns of FIG. 1 that the crystal grain size of NiO in the catalyst obtained in example 1 is significantly smaller than that in the catalyst obtained in comparative example 1.
As can be seen from a comparison of example 1 and comparative example 1, the support not loaded with the organic adsorbent is impregnated two or three times to achieve the required metal loading, and the drying, baking and other procedures are required for each time due to multiple impregnations, so that the size of NiO crystal grains on the support is increased, the preparation process is complicated, and the production cost of the catalyst is increased.
(2) Activity evaluation
The catalyst was activated and a methane steam reforming hydrogen production reaction was performed under the same conditions as in example 1. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 72.2%.
Meanwhile, the carbon deposit analysis was performed on the catalyst obtained in comparative example 1 after 50 hours of reaction, and the carbon deposit analysis was compared with the carbon deposit analysis performed on the catalyst obtained in example 1 after 2000 hours of reaction, and it was found that the carbon deposit amount of the catalyst obtained in comparative example 1 after 50 hours of reaction was 1.7wt% and the carbon deposit amount of the catalyst obtained in example 1 after 2000 hours of reaction was 0.06wt%. This demonstrates that the catalyst prepared by the process of the present invention has excellent anti-coking properties.
Comparative example 2
(1) Preparation of the catalyst
A catalyst was prepared in the same manner as in example 1, except that no auxiliary agent was added in preparing the metal impregnation solution, to obtain the desired catalyst for steam reforming of methane to produce hydrogen. The fluorescence analysis results show that the concentration of NiO in the catalyst is 13.5wt%, and the rest is carrier. The calculated crystal grain size of NiO was 6.2nm.
(2) Activity evaluation
0.2g of the catalyst was weighed and packed in a fixed bed reactor, and the catalyst was reduced at 550℃for 3 hours under normal pressure in a pure hydrogen atmosphere to perform reduction activation. After the reduction is finished, heating to 700 ℃ in a hydrogen atmosphere, and switching raw material gas to react, wherein the volume ratio of water to methane in the raw material gas is 2:1, methane carbon space velocity of 4000h -1 The reaction pressure is normal pressure. The tail gas composition was analyzed by gas chromatography on-line sampling, and the conversion of methane was calculated to be 84.8%.
From the results, the preparation method of the catalyst and the prepared catalyst have better reaction activity, stability and anti-carbon performance, and can continuously, efficiently and stably run for more than 2000 hours without deactivation.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.
Claims (13)
1. A methane steam reforming catalyst, characterized in that the catalyst comprises a carrier and an active metal component and an auxiliary component supported on the carrier; wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; wherein the average grain size of the active metal component is 3-12nm, the content of the carrier is 72-94wt% based on the total amount of the catalyst, the content of the active metal component is 5.9-18wt% based on oxide, and the content of the auxiliary component is 0.1-10wt%.
2. The catalyst of claim 1, wherein the active metal component has an average crystallite size of 4-9nm;
preferably, the carrier is present in an amount of 81 to 91wt% based on the total amount of catalyst, the active metal component is present in an amount of 8 to 14wt% based on the oxide, and the auxiliary component is present in an amount of 1 to 5wt%.
3. The catalyst according to claim 1 or 2, wherein the support is a-Al 2 O 3 、MgO-Al 2 O 3 、CaO-Al 2 O 3 At least one of SiC and BN, preferably alpha-Al 2 O 3 ；
Preferably, the auxiliary component is selected from at least one of La, ce, pr and Sm, preferably La and/or Ce;
preferably, the molar ratio of the auxiliary component to the active metal component is 0.03-0.2, calculated as element: 1, preferably 0.04-0.15:1.
4. a method of preparing a methane steam reforming catalyst, the method comprising: contacting the carrier loaded with the organic adsorbent with impregnating solution, and then performing first drying and roasting;
the impregnating solution contains a soluble compound of an active metal component and a soluble compound of an auxiliary component, wherein the active metal component is Ni, and the auxiliary component is at least one of rare earth metals; the carrier loading the organic adsorbent and the impregnating solution are used in an amount such that the content of the carrier is 72-94wt%, the content of the active metal component is 5.9-18wt% and the content of the auxiliary component is 0.1-10wt% in terms of oxide in the prepared catalyst.
5. The process according to claim 4, wherein the organic adsorbent-supporting carrier, the soluble compound of the active metal component and the soluble compound of the auxiliary component are used in such amounts that the carrier is contained in an amount of 81 to 91% by weight, the active metal component is contained in an amount of 8 to 14% by weight, and the auxiliary component is contained in an amount of 1 to 5% by weight, based on the total amount of the catalyst to be produced.
6. The production method according to claim 4 or 5, wherein the soluble compound of the auxiliary component and the soluble compound of the active metal component are used in such an amount that, on an elemental basis, the molar ratio of the auxiliary component to the active metal component in the produced catalyst is 0.03 to 0.2:1, preferably 0.04-0.15:1, a step of;
preferably, the carrier is alpha-Al 2 O 3 、MgO-Al 2 O 3 、CaO-Al 2 O 3 At least one of SiC and BN, preferably alpha-Al 2 O 3 ；
Preferably, the auxiliary component is selected from at least one of La, ce, pr and Sm, preferably La and/or Ce;
preferably, the concentration of the soluble compound of the active metal component in the impregnation liquid is 0.5-2.5g/mL, more preferably 0.8-1.5g/mL.
7. The preparation method according to any one of claims 4 to 6, wherein the contacting is for a period of 10 to 60min, preferably 20 to 35min;
preferably, the first drying conditions include: the drying temperature is 60-140 ℃, preferably 70-110 ℃; the drying time is 1-6h, preferably 2-4h;
preferably, the roasting conditions include: the roasting temperature is 300-800 ℃, preferably 400-550 ℃; the calcination time is 1 to 5 hours, preferably 2 to 4 hours.
8. The production method according to any one of claims 4 to 7, wherein the organic adsorbent is at least one selected from the group consisting of starch, glucose, α -cyclodextrin, β -cyclodextrin, γ -cyclodextrin and maltosaccharin; preferably at least one selected from glucose, beta-cyclodextrin and gamma-cyclodextrin; further preferred are beta-cyclodextrin and/or gamma-cyclodextrin;
preferably, the content of the organic adsorbent is 0.05 to 3wt%, more preferably 0.2 to 1.5wt%, based on the total amount of the organic adsorbent-supporting carrier.
9. The production method according to any one of claims 4 to 8, wherein the organic adsorbent-loaded carrier is obtained by the following production method: contacting the solution containing the organic adsorbent with a carrier to obtain a contact product, and then performing pre-dewatering and secondary drying;
preferably, the concentration of the organic adsorbent-containing solution is 0.005 to 0.1g/mL, more preferably 0.009 to 0.07g/mL;
preferably, the pre-dewatering comprises: pre-dewatering the contact product in the presence of warm air until no surface water is present;
preferably, the temperature of the warm air is 30-80 ℃, preferably 35-60 ℃;
preferably, the second drying temperature does not exceed 100 ℃;
preferably, the second drying mode is at least one selected from freeze drying, low-temperature vacuum drying and low-temperature hot air drying, and is preferably freeze drying;
preferably, the conditions of freeze-drying include: the temperature is between minus 30 ℃ and minus 5 ℃ and the time is between 1 and 20 hours;
preferably, the conditions of the low-temperature vacuum drying include: vacuum degree is-0.09 MPa to-0.05 MPa, temperature is 30-70 ℃, and drying time is 2-10h;
preferably, the conditions of the low-temperature hot air drying include: the temperature is 40-80 ℃, the flow rate of hot air is 0.1-0.5m/s, and the drying time is 2-10h.
10. A steam methane reforming catalyst prepared by the process of any one of claims 4 to 9.
11. A method for producing hydrogen from steam reforming of methane, the method comprising: contacting methane and water with a catalyst under conditions for steam reforming of methane to produce hydrogen, wherein the catalyst is a steam methane reforming catalyst according to any one of claims 1-3 and 10.
12. The method of claim 11, wherein the contacting is performed in a fixed bed reactor;
preferably, the conditions for steam reforming methane to produce hydrogen include: the volume ratio of water to methane is (1.2-5): 1, preferably (2.5-3.5): 1, a step of; the reaction temperature is 600-900 ℃, preferably 650-850 ℃; the pressure is 0-4MPa, preferably 1.5-3.5MPa; methane carbon space velocity of 400-5000h -1 Preferably 600-4000h -1 。
13. The method according to claim 11 or 12, wherein the method further comprises: before the reaction, the catalyst is reduced and activated in the atmosphere containing hydrogen;
preferably, the conditions of the reductive activation include: the reduction temperature is 300-800 ℃, preferably 400-600 ℃; the reduction time is 0.5 to 10 hours, preferably 1 to 5 hours, further preferably 2 to 4 hours; the reduction pressure is 0 to 2MPa, preferably 0 to 1MPa, more preferably 0 to 0.5MPa;
preferably, the hydrogen-containing atmosphere is hydrogen or a mixed gas of hydrogen and inert gas;
preferably, the volume content of hydrogen in the mixed gas is 10-80%.
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