Hydrothermal catalytic reforming hydrogen production catalyst carrier as well as preparation method and application thereof

Abstract

The invention relates to the technical field of biofuels, in particular to a hydrothermal catalytic reforming hydrogen production catalyst carrier as well as a preparation method and application thereof. By adding an iron element into copper-manganese spinel, the defects that a single metal oxide carrier is low in oxygen carrying capacity, easy to coke and the like are overcome; and the catalytic activity of the reforming catalyst is further improved by optimizing the content of Fe2O3 in the carrier (Fe-Cu) Mn2O4 and the content of Ru in the catalyst Ru / CeO2 / (Fe-Cu) Mn2O4.

Description

Technical Field

[0001] The present invention relates to the technical field of biofuels, and in particular to a hydrothermal catalytic reforming hydrogen production catalyst carrier and a preparation method and application thereof, and more particularly to a reforming catalyst using a spinel-type composite material as a carrier and a preparation method thereof. Background Art

[0002] Fossil fuels, such as oil, natural gas and coal, are unsustainable non-renewable energy sources. Renewable carbon-based biomass energy sources are abundant and widely exist in daily wastes, such as livestock manure, straw, domestic garbage, sewage sludge and waste oil, with huge reserves. These biomasses can be converted and processed into biofuels to serve industrial production and daily life. An important application area of ​​biofuels is hydrothermal catalytic reforming to produce hydrogen for use in the field of fuel cells. The basic principle is that under the action of special catalysts, the long-chain molecules in biofuels are cracked into short-chain molecules through hydrothermal reactions, while mainly releasing hydrogen and producing some by-products such as carbon monoxide, methane and carbon dioxide for fuel cell power generation. Therefore, the use of biofuels to produce hydrogen is a technical approach to efficiently utilize biomass resources, which has great social and economic value in reducing greenhouse gas emissions, alleviating energy crises and promoting carbon neutrality.

[0003] The technology of hydrothermal catalytic reforming of biofuels to produce hydrogen has been developed to date. Although there is a relatively mature production process, its popularity has always been limited by the high efficiency and long-term stability of carbon conversion rate and hydrogen yield. The reason for the difficulty in popularizing the technology is that the composition of biofuels is complex and the structural stability of the catalyst is poor under high temperature conditions, which makes it easy to produce a large amount of coke accumulation during the reforming process, resulting in catalyst poisoning or even failure. Therefore, the development of structurally stable and efficient catalysts has become an important development direction in this field. Existing reforming catalysts generally contain three components: active metals, promoters and carriers. Among them, active metals mainly include precious metals such as Rh, Ru, Pt, Pd, Re, and transition metals such as Fe, Cu, Ni, and Co. In contrast, although precious metals have higher catalytic activity, they are expensive and easily poisoned by carbon deposition; although transition metals have low cost, good reaction activity and gas selectivity, they are not resistant to high temperatures and are prone to overheating and sintering, resulting in a decrease in hydrogen yield. In addition, the carrier, as the skeleton of the catalyst, can enhance the dispersibility of the active metal and increase the contact area between the active metal and the biofuel and water vapor in the catalytic reforming process, and can even provide catalytic active sites to play the role of a co-catalyst. However, commonly used metal oxide carriers, such as SiO2, Al2O3, ZrO2 and CeO2, have the problem of easy coking and collapse at high temperatures, which leads to a large amount of agglomeration and sintering of the active metal. Although the use of rare earth metal oxides and alkaline earth metal oxide promoters such as CeO2 and MgO and precious metal promoters can change the electronic structure, ion valence and active sites of the catalyst, enhance the interaction between the active metal and the carrier, improve the dispersibility of the active metal on the carrier, and improve the anti-sintering and anti-coking properties of the reforming catalyst, the optimization of the promoter alone still cannot meet the actual application requirements. This is because the reforming catalyst is essentially a multiphase catalyst, and its ultimate catalytic activity, structural stability and high temperature resistance are inseparable from the above-mentioned three main components and their interrelationships.

[0004] In order to obtain the structural stability required by the carrier at high temperature, spinel carriers with high hardness and thermal stability have been verified. For example, spinel NiAl2O4 can play a good anchoring role on Ni catalysts, improve the interaction between the two and the dispersion of Ni on the carrier, and improve the anti-coking performance and thermal stability of the reforming catalyst. However, the Ni in NiAl2O4 will actually be completely reduced at high temperatures (~850℃), resulting in catalytic failure; in order to obtain high catalytic efficiency, various precious metal and transition metal catalysts have also been widely studied. However, the multi-phase composite between metal catalysts, carriers and promoters, and how the composite three-phase reforming catalyst can simultaneously achieve structural thermal stability, anti-sintering, anti-coking, high catalytic efficiency, low-cost preparation and long service life are important issues that need to be continuously considered in the development of biofuel hydrothermal catalytic reforming hydrogen production technology. Especially the development of high-performance carriers, because the carrier is the skeleton to which the catalyst and promoter are attached. Only when the carrier has a stable structure and excellent high-temperature resistance can it ensure that the metal catalyst and promoter on its surface are evenly dispersed and well combined, thus making the reforming catalyst have the basic prerequisite for improving performance. Summary of the invention

[0005] Copper manganese spinel is a low-cost, high-performance VOCs catalytic combustion catalyst, but it also faces the problem of poor anti-coking. In view of this, the present invention adds iron to the copper manganese spinel to make up for the defects of the copper manganese spinel carrier such as low oxygen loading capacity and easy coking.

[0006] In one aspect, the present invention provides a spinel-type reforming catalyst carrier, wherein the chemical formula of the catalyst carrier is (Fe-Cu)Mn2O4.

[0007] According to a specific embodiment of the present invention, the molar ratio of Fe, Cu and Mn in the (Fe-Cu)Mn2O4 is as follows:

[0008] Fe2O3:CuO:MnO2 is (25-34):(16-25):100.

[0009] The molar percentage of the Fe2O3 in the total of the Fe2O3 and the CuO is 50-67%;

[0010] The molar ratio of the sum of the Fe2O3 and the CuO to the MnO2 is 0.5:1.

[0011] By adding iron element to copper-manganese spinel, the present invention makes Fe2O3 have stronger oxygen storage and release capacity than CuO and MnO2, which makes up for the defects of copper-manganese spinel carrier such as low oxygen carrying capacity and easy coking.

[0012] A second aspect of the present invention provides a method for preparing a (Fe-Cu)Mn2O4 spinel reforming catalyst carrier, comprising:

[0013] A. mixing CuO, Fe2O3 and MnO2 powders to obtain mixed powder;

[0014] B. sintering the mixed powder in an argon atmosphere to obtain a spinel carrier (Fe-Cu)Mn2O4,

[0015] in,

[0016] The molar ratio of Fe2O3, CuO and MnO2 is (25-34):(16-25):100.

[0017] According to a specific embodiment of the present invention, in step A, the mixing treatment method is: CuO, Fe2O3, and MnO2 powders are sequentially subjected to ethanol dispersion treatment, grinding treatment, and drying treatment;

[0018] The grinding process lasts for 6-12 hours;

[0019] The temperature during the drying process is 70-90°C and the duration is 6-10h;

[0020] The molar percentage of the Fe2O3 in the total of the Fe2O3 and the CuO is 50-67%;

[0021] The molar ratio of the sum of the Fe2O3 and the CuO to the MnO2 is 0.5:1.

[0022] According to a more specific embodiment of the present invention, in the mixed powder, the molar ratio of (CuO+Fe2O3) to MnO2 is 0.5:1, wherein the molar percentage of Fe2O3 in (CuO+Fe2O3) is 50-67%.

[0023] The inventors of the present application improved the catalytic activity by optimizing the content of Fe2O3 in the carrier (Fe-Cu)Mn2O4, thereby reducing the content of short-chain gaseous hydrocarbons in the hydrogen-rich synthesis gas, curbing the coking behavior on the catalyst surface from the source, and maintaining the high catalytic activity of the catalyst.

[0024] According to a specific embodiment of the present invention, in step B, the temperature during the sintering treatment is 1300-1500°C for 3-5 hours. The sintered spinel carrier (Fe-Cu)Mn2O4 is naturally cooled, crushed, ground and sieved to obtain a carrier (Fe-Cu)Mn2O4 spinel powder.

[0025] According to a specific embodiment of the present invention, the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier provided by the present invention has a stronger oxygen storage and release capacity than the traditional copper-manganese spinel catalyst carrier, and can produce excellent oxygen flow performance, thereby improving the catalytic activity of the catalyst.

[0026] The third aspect of the present invention provides the use of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier described in the second aspect in the preparation of a reforming catalyst.

[0027] A fourth aspect of the present invention provides a method for preparing a Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst, comprising:

[0028] a. Add concentrated nitric acid and concentrated ammonia water to deionized water to obtain a mixed solution A;

[0029] b. The (Fe-Cu)Mn2O4 spinel reforming catalyst support of the first aspect is mixed with the mixed solution A and stirred to obtain a suspension 1;

[0030] c. adding cerium nitrate hexahydrate to the suspension 1 to obtain a suspension 2;

[0031] d. Add concentrated aqueous ammonia and ethylene glycol to the suspension 2, stir at 100-110 ° C for 3-6 hours to obtain a suspension 3;

[0032] e. The suspension 3 was separated into solid and liquid by vacuum filtration to obtain a solid slurry;

[0033] f. The solid slurry was dried and then heated to 290-310 ° C and kept warm for 5-7h to obtain powder B. Ethanol was added to the powder B to dissolve and obtain a suspension 4.

[0034] g. After the ruthenium acetylacetonate is dissolved in the ethanol solution, the suspension 4 is stirred at 94-98 ° C until the solvent is completely evaporated to obtain a powder C;

[0035] h. The powder was gradually heated to 390-410°C and kept at this temperature for 5-7h to obtain Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst.

[0036] The inventors of the present application optimize the Ru content in the catalyst to avoid the reduction of specific surface area and total pore volume caused by excessive loading of Ru on the catalyst surface, maintain sufficient contact between the catalyst and the fuel, and thus produce high catalytic activity.

[0037] In step b, the working concentration of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier in the suspension 1 is 0.28-0.286 g / ml;

[0038] In step c, in the suspension 2, the working concentration of the cerium nitrate hexahydrate is 0.034-0.037 g / ml;

[0039] According to a specific embodiment of the present invention, the rotation speed during stirring is 400 r / min, and the concentration of alcohol used to dissolve the substance is 75%-98%.

[0040] According to a specific embodiment of the present invention, the mass ratio of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier, cerium nitrate hexahydrate and ruthenium acetylacetonate input when preparing the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst is (17151-17154):(2520-2523):(3.15-4.98).

[0041] The Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst synthesized by the present invention undergoes a steam reforming catalytic process at 900°C for 72 hours, and its structure is still well preserved. Its carbon conversion rate for biofuels is still as high as 96%, and its hydrogen yield is still maintained at a high level of 86%. The content of short-chain gaseous hydrocarbons in the hydrogen-rich synthesis gas is as low as 2%, thereby curbing the occurrence of coking on the catalyst surface from the source.

[0042] The fifth aspect of the present invention provides a Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst prepared by the method described in the fourth aspect.

[0043] The sixth aspect of the present invention provides the use of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier described in the first aspect and the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst described in the fifth aspect in hydrothermal catalytic reforming to produce hydrogen.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) The synthesized (Fe-Cu)Mn2O4 carrier is resistant to high temperatures and contains Fe and Cu transition metals, which can act as a co-catalyst;

[0046] (2) The synthesized Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst remains intact after 72 hours of steam reforming catalysis at 900°C. Its carbon conversion rate for biofuels remains as high as 96%, and its hydrogen yield remains at a high level of 86%. The content of short-chain gaseous hydrocarbons in the hydrogen-rich synthesis gas is as low as 2%, which curbs the occurrence of coking on the catalyst surface from the source and is conducive to maintaining the high catalytic activity of the catalyst.

[0047] (3) The Ru metal catalyst and CeO2 promoter on the surface of the synthesized Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst are highly dispersed, and have strong interaction with the (Fe-Cu)Mn2O4 carrier, excellent resistance to high-temperature sintering, and no adverse conditions such as metal catalyst agglomeration, sintering, and reduction will occur;

[0048] (4) The (Fe-Cu)Mn2O4 carrier significantly improves the loading capacity of Ru catalyst and can also maintain the high dispersion of Ru on its surface;

[0049] (5) The synthesized (Fe-Cu)Mn2O4 carrier combines the excellent properties of Fe2O3, Mn2O3 and CuO, making up for the defects of single metal oxide carriers such as low oxygen loading capacity and easy coking, and synergistically produces high reforming catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0051] Figure 1 The metallographic microscopic images (ac) and particle size distribution statistical analysis (d) of the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst in one embodiment of the present invention are shown in FIG. Figure 1 The scale bar in (a) is 500 μm. Figure 1 The scale bar in (b) is 200 μm. Figure 1 The scale bar in (c) is 50 μm;

[0052] Figure 2 This is a scanning electron microscope (SEM) image of a Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst in one embodiment of the present invention, with a scale of 500 nm;

[0053] Figure 3 The following is a scanning electron microscope (SEM) image of a Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst and its element distribution diagram in one embodiment of the present invention, wherein the scale of the SEM image is 2.5 μm;

[0054] Figure 4 The XRD diagram of the (Fe-Cu)Mn2O4 carrier and the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst in one embodiment of the present invention;

[0055] Figure 5This is a flow chart of a reforming hydrogen production device in one embodiment of the present invention.

[0056] Figure 6 The carbon conversion rate and hydrogen yield bar graph of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 after catalytic reforming ( Figure 6 a), and the bar chart of the relative percentage content of each component in the hydrogen-rich synthesis gas ( Figure 6 b) in;

[0057] Figure 7 The carbon conversion rate and hydrogen yield bar graph of the catalysts prepared in Example 2, Example 4, Example 5 and Comparative Example 3 after catalytic reforming ( Figure 7 a), and the relative percentage content of each component in the hydrogen-rich synthesis gas ( Figure 7 b) in;

[0058] Figure 8 A comparison chart of specific surface area and total pore volume of catalysts prepared in Example 2, Example 4, Example 5 and Comparative Example 3 of the present invention;

[0059] Fig. 9 This is a comparative test of the catalytic activity and thermal stability of the catalysts in Examples 1-5 of the present invention and Comparative Examples 1-2, wherein: Fig. 9 The a carbon conversion rate line chart in Fig. 9 b in FIG. 1 is a line graph of hydrogen yield. DETAILED DESCRIPTION

[0060] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0061] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0062] In this document, the terms “contain”, “include” or “comprise” are open expressions, that is, they include the contents specified in the present invention but do not exclude other contents.

[0063] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0064] In the present invention, Ru / CeO2 / (Fe-Cu)Mn2O4 is synonymous with Ru@CeO2@(Fe-Cu)Mn2O4, and “@” represents the load.

[0065] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention provides drawings, which are part of the disclosure of the present invention. They are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. By referring to these contents, ordinary technicians in this field should be able to understand other possible implementation methods and advantages of the present invention.

[0066] In the present application, the specific surface area and total pore volume of the catalyst are measured by a fully automatic BET specific surface (area) analysis tester; the components in the hydrogen-rich synthesis gas after catalytic reforming, as well as the relative percentage content of each component, the carbon conversion rate and the hydrogen yield are all measured by a high-performance gas chromatograph.

[0067] The purchase sources and product numbers of the reagents used in the examples of this application are shown in Table 1:

[0068] Table 1

[0069] name Manufacturer Product Number <![CDATA[Fe2O3]]> Shanghai MacLean Biochemical Technology Co., Ltd. F923195 CuO Shanghai MacLean Biochemical Technology Co., Ltd. C835833 <![CDATA[MnO2]]> Shanghai MacLean Biochemical Technology Co., Ltd. M813969 Ethanol Shanghai MacLean Biochemical Technology Co., Ltd. E766256 Concentrated ammonia Shanghai MacLean Biochemical Technology Co., Ltd. A765779 Ethylene glycol Shanghai MacLean Biochemical Technology Co., Ltd. E808735 Cerium nitrate hexahydrate Shanghai MacLean Biochemical Technology Co., Ltd. C804686 Ruthenium acetylacetonate Shanghai MacLean Biochemical Technology Co., Ltd. R795404

[0070] The scheme of the present disclosure will be explained below in conjunction with the examples. Those skilled in the art will appreciate that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the art or the product instructions are used. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present invention.

[0071] Example 1

[0072] a. Preparation of carrier:

[0073] According to the molar ratio of (CuO+Fe2O3) to MnO2 of 0.5:1, in which the molar percentage of Fe2O3 in (CuO+Fe2O3) is 50%, the powder raw material is weighed with an electronic balance, poured into a ball mill, and ethanol is added to fully disperse it, and then it is placed in a ball mill for 8 hours; then, it is transferred to an oven and dried at 80°C for 8 hours; the dried powder is crushed and poured into an alumina crucible, flattened, and sintered in an argon atmosphere; the sintering temperature is 1400°C, and the heat preservation time is 4 hours. After natural cooling, it is crushed and ground, and passed through a 300-mesh sieve to obtain the carrier (Fe-Cu)Mn2O4 spinel powder.

[0074] b. Preparation of reforming catalyst:

[0075] (b1) Take a 1-liter beaker and add 500 mL of deionized water. Take 1 mL of concentrated nitric acid (purchased from Linyi Luguang Chemical Co., Ltd.) and add it dropwise into the deionized water, stirring evenly with a glass rod. Then, take 2 mL of concentrated ammonia water and add it dropwise into the above solution, stirring evenly to prepare mixed solution A.

[0076] (b2) Take a 150mL beaker, take 17.1534g of carrier (Fe-Cu)Mn2O4 spinel powder and pour it into the beaker, add 60mL of the above-configured mixed solution A, and magnetically stir it at a speed of 400r / min to form a suspension; then, weigh 2.5210g of cerium nitrate hexahydrate, dissolve it in 10mL of deionized water, and slowly add it dropwise to the suspension; then, take 1mL of concentrated ammonia water, slowly add it dropwise to the suspension, and magnetically stir it at 400r / min for 15min; then, take 30mL of ethylene glycol and pour it therein, transfer it to an oil bath, heat it to 105°C, and keep it warm for 4h under magnetic stirring at 400r / min to terminate the reaction.

[0077] (b3) The suspension obtained in the reaction of b2 was subjected to liquid-solid separation by vacuum filtration; the obtained solid slurry was dried at 80°C; then, the dried powder was transferred to a muffle furnace, the temperature was increased to 300°C at 2°C / min, and the temperature was kept for 6 hours and then naturally cooled to obtain powder B.

[0078] (b4) Powder B in b3 was transferred to a 150 mL beaker, and 60 mL of ethanol was added and stirred magnetically to form a suspension; then, 4.98 mg of ruthenium acetylacetonate (C 15 H 21 O6Ru) was poured into a 50 mL beaker, and 25 mL of ethanol was added and stirred until fully dissolved; then, C 15 H 21 The ethanol solution of O6Ru was added dropwise to the ethanol suspension of powder B, and magnetically stirred at 95°C and 400r / min for 6h until the solvent in the beaker was completely evaporated; finally, the dry powder obtained after evaporation was transferred to a muffle furnace, heated to 400°C at 2°C / min, and kept warm for 6h before naturally cooling to obtain Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst.

[0079] The Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst prepared in Example 1 was imaged by metallographic microscope and its particle size distribution was statistically analyzed. Figure 1 As shown, the particle size of the reforming catalyst powder synthesized in this example is mainly distributed in the range of 30-90 μm.

[0080] The Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst prepared in Example 1 was imaged by scanning electron microscope. Figure 2 As shown, a large number of Ru / CeO2 particles are densely attached to the surface of the (Fe-Cu)Mn2O4 carrier.

[0081] Example 2

[0082] Compared with Example 1, the difference of the embodiment is that the molar percentage of Fe2O3 in (CuO+Fe2O3) is 59.4%, and the rest are the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0083] The Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst prepared in Example 2 was scanned by a scanning electron microscope to obtain a scanning electron microscope image and an element distribution map. The results are as follows: Figure 3 As shown, the Ru element is evenly and densely distributed on the surface of the CeO2 particles, and the Fe and Cu elements are blocked because their surfaces are loaded with a large number of Ru / CeO2 particles. Although the surface element analysis test of SEM is difficult to observe, the presence of Fe and Cu elements can still be detected.

[0084] X-ray diffraction analysis was performed on the (Fe-Cu)Mn2O4 carrier and Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst prepared in Example 2. The results are as follows: Figure 4 As shown, the synthesized (Fe-Cu)Mn2O4 support is a spinel crystal, and the XRD spectrum of the synthesized Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst has an additional Ru / CeO2 crystallization peak (the peak marked by the black square in the figure).

[0085] Example 3

[0086] Compared with Example 1, the difference of the embodiment is that the molar percentage of Fe2O3 in (CuO+Fe2O3) is 67%, and the rest is the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0087] Example 4

[0088] Compared with Example 2, the difference of the embodiment is that ruthenium acetylacetonate (C 15 H 21 The dosage of O6Ru) is 3.12 mg, and the rest are the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0089] Example 5

[0090] Compared with Example 2, the difference of the embodiment is that ruthenium acetylacetonate (C 15 H 21 The dosage of O6Ru) is 4.06 mg, and the rest are the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0091] Comparative Example 1

[0092] Compared with Example 1, the difference of the embodiment is that the molar percentage of Fe2O3 in (CuO+Fe2O3) is 0, and the rest are the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0093] Comparative Example 2

[0094] Compared with Example 1, the difference of the embodiment is that the molar percentage of Fe2O3 in (CuO+Fe2O3) is 70%, and the rest are the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0095] Comparative Example 3

[0096] Compared with Example 2, the difference of the embodiment is that ruthenium acetylacetonate (C 15 H 21 The dosage of O6Ru) is 5.11 mg, and the rest are the same. The conditions for producing hydrogen by steam catalytic reforming of biomass fuel are the same as those in Example 1.

[0097] Hydrogen production from steam catalytic reforming of biomass fuels:

[0098] The reforming catalysts prepared in Examples 1-5 and Comparative Examples 1-4 were used in Figure 5 In the reforming hydrogen production process shown, the selected biomass fuel is a representative extract of Scots pine powder, which can be obtained by sealing microwave heating assisted hydrothermal treatment of Scots pine powder and then filtering. The control conditions of the steam catalytic reforming hydrogen production process of biomass fuel are as follows: the reaction space velocity is controlled to be 20000h -1 The reforming temperature in the reactor is 900°C, the reforming pressure is 1 atm, the molar ratio of water vapor to C element in the fuel is 6:1, and the reaction time is 10 h.

[0099] The carbon conversion rate and hydrogen yield of the catalysts prepared in Examples 1-3 and Comparative Examples 1-2 after catalytic reforming, as well as the relative percentage content of each component in the hydrogen-rich synthesis gas, were measured. The results are as follows: Figure 6 As shown, Figure 6a in the figure is the carbon conversion rate and hydrogen yield of the catalyst after catalytic reforming, which shows that when the molar content of Fe2O3 is in the range of 50% to 67% (Examples 1-3), the carbon conversion rate and hydrogen yield that the catalyst can produce will gradually increase with the increase of Fe2O3 content; when the Fe2O3 content is 0 (Comparative Example 1), the carbon conversion rate and hydrogen yield will be significantly lower than those of Examples 1-3; however, when the Fe2O3 content is 70% (Comparative Example 2), the carbon conversion rate and hydrogen yield are higher than those of Examples 1-3. The reason for this phenomenon that the carbon conversion rate and hydrogen yield increase with the increase of the proportion of Fe2O3 in the catalyst carrier is that the (Fe-Cu)Mn2O4 composite carrier is rich in oxygen species, among which Fe2O3 has a stronger oxygen storage and release capacity than CuO and MnO2, and can produce excellent oxygen flow performance, thereby producing gradually increasing catalytic activity; Figure 6 b in is the component analysis of hydrogen-rich synthesis gas, and the results show that the components of hydrogen-rich synthesis gas mainly include H2, CO, CO2, CH4 and other short-chain gaseous hydrocarbons. The higher the percentage of H2, the higher the catalytic efficiency, and the larger the percentage of short-chain gaseous hydrocarbons, the greater the risk of catalyst surface coking. In comparative example 1, the percentage of H2 in hydrogen-rich synthesis gas is the lowest (61%), and the content of short-chain gaseous hydrocarbons is as high as 19%. These short-chain gaseous hydrocarbons are the main factors for coking in the reforming process, and their content is too high, which is extremely easy to cause catalyst surface coking, hindering the effective contact between the catalyst and the fuel, and producing catalyst poisoning. In addition, Examples 1-3 all show very high similar levels of carbon conversion and hydrogen yield, but the proportion of short-chain gaseous hydrocarbons in Example 2 is the lowest among the three (2%), which means that the anti-coking performance of the catalyst in Example 2 and the comprehensive performance of catalytic activity are optimal. Although the percentage of H2 in the hydrogen-rich synthesis gas in Comparative Example 2 with the highest Fe2O3 content is as high as 87%, the content of short-chain gaseous hydrocarbons therein also reaches 11%, which is significantly higher than that of Examples 1 to 3. The above comparative analysis of catalytic performance shows that the increase of Fe2O3 content in the (Fe-Cu)Mn2O4 composite carrier is conducive to the improvement of the catalytic performance of the catalyst, but too high Fe2O3 content may cause coking on the catalyst surface.

[0100] Based on the Fe2O3 content in the (Fe-Cu)Mn2O4 composite carrier determined in Example 2, the ruthenium acetylacetonate (C 15 H 21 The effect of the dosage of O6Ru) on the catalytic activity was measured, and the carbon conversion rate and hydrogen yield of the catalysts prepared in Example 2, Example 4, Example 5 and Comparative Example 3 after catalytic reforming, as well as the relative percentage content of each component in the hydrogen-rich synthesis gas were measured. The results are shown in Figure 7 As shown, with the addition of ruthenium acetylacetonate (C 15H 21 With the gradual increase of the dosage of CeO2 / (Fe-Cu)Mn2O4, the content of Ru in the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst will inevitably increase gradually, thus causing a change in catalytic activity. As the Ru content gradually increases, the carbon conversion rate and hydrogen yield will gradually increase, so that in Example 2, the carbon conversion rate is as high as 96%, the hydrogen yield is as high as 86%, and the percentage of H2 in its hydrogen-rich synthesis gas is as high as 81%. This shows that in Example 4, Example 5 and Example 2, the loading of Ru is an effective process, and Ru can be fully dispersed and firmly combined on the (Fe-Cu)Mn2O4 composite carrier with the help of CeO2, thereby giving full play to the catalytic activity of the catalyst. However, when ruthenium acetylacetonate (C 15 H 21 When the dosage of Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst continues to increase to 5.11 mg (Comparative Example 3), the carbon conversion rate and hydrogen yield in Comparative Example 3 are sharply reduced compared with those in Example 2. The inventors speculate that the excessive loading of Ru causes Ru to enter the pores inside the catalyst, causing pore blockage, resulting in a sharp decrease in the specific surface area and pore volume of the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst, thereby reducing the catalytic activity of the catalyst.

[0101] The inventors further measured the specific surface area and total pore volume of the catalysts prepared in Example 2, Example 4, Example 5 and Comparative Example 3. The results are as follows: Figure 8 As shown in the figure, it is shown that as the Ru loading gradually increases (in Example 4, Example 5 and Example 2, respectively), the specific surface area and total pore volume of the corresponding catalysts do not change much and are maintained at a high level. However, when the Ru loading is too high (Comparative Example 3), the specific surface area and total pore volume of the catalyst in Comparative Example 3 are reduced to 73m 2 / g and 0.369cm 3 The reason for the sharp decrease in the specific surface area and total pore volume of the catalyst is that the excessive loading of Ru causes Ru to enter the internal pores of the catalyst, causing pore blockage.

[0102] Comparative test of thermal stability of catalytic performance: The reforming catalysts synthesized in Examples 1-5 and Comparative Examples 1-2 were subjected to continuous reaction for 72 hours under the process control conditions of steam catalytic reforming of biomass fuel to produce hydrogen in the examples, and the changes in carbon conversion rate and hydrogen yield of each catalyst were compared and analyzed. The results are shown in Fig. 9As shown, the carbon conversion rate and hydrogen yield of Example 2 fluctuate less, and can be maintained at high levels of about 96% and 86% respectively; the carbon conversion rate and hydrogen yield in Example 1 and Examples 3-5 can also be maintained near their initial levels; this shows that the catalytic activity of the catalysts in Examples 1-5 can be stably present for a long time, which is due to the efficient thermal stability of the spinel (Fe-Cu) Mn2O4 composite carrier. However, in comparison, the carbon conversion rate and hydrogen yield in Comparative Example 1 began to gradually decrease at 20 hours, and the carbon conversion rate and hydrogen yield in Comparative Example 2 began to gradually decrease at 40 hours, which is closely related to the property of easy coking on the catalyst surface.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A spinel reforming catalyst carrier, characterized in that: The chemical formula is (Fe-Cu)Mn2O4.

2. The spinel reforming catalyst carrier according to claim 1, characterized in that The molar ratio of Fe, Cu and Mn in the (Fe-Cu)Mn2O4 is calculated as follows: Fe2O3:CuO:MnO2 is (25-34):(16-25):

100.

3. A method for preparing a (Fe-Cu)Mn2O4 spinel reforming catalyst carrier, characterized in that: include: A. mixing CuO, Fe2O3 and MnO2 powders to obtain mixed powder; B. sintering the mixed powder in an argon atmosphere to obtain a spinel carrier (Fe-Cu)Mn2O4, in, The molar ratio of Fe2O3, CuO and MnO2 is (25-34):(16-25):

100.

4. The method according to claim 1, characterized in that: In step A, the mixing treatment method is: CuO, Fe2O3, and MnO2 powders are sequentially subjected to ethanol dispersion treatment, grinding treatment, and drying treatment; The grinding process lasts for 6-12 hours; The temperature during the drying process is 70-90°C and the duration is 6-10h; The molar percentage of the Fe2O3 in the total of the Fe2O3 and the CuO is 50-67%; The molar ratio of the sum of the Fe2O3 and the CuO to the MnO2 is 0.5:1; In step B, the sintering process is carried out at a temperature of 1300-1500° C. for 3-5 hours.

5. Use of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier according to claim 1 in the preparation of reforming catalyst.

6. A method for preparing a Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst, characterized in that: include: a. Add concentrated nitric acid and concentrated ammonia water to deionized water to obtain a mixed solution A; b. The (Fe-Cu)Mn2O4 spinel reforming catalyst carrier according to claim 1 is mixed with the mixed solution A and stirred to obtain a suspension 1; c. adding cerium nitrate hexahydrate to the suspension 1 to obtain a suspension 2; d. Add concentrated aqueous ammonia and ethylene glycol to the suspension 2 in sequence, stir at 100-110 ° C for 3-6 hours to obtain a suspension 3; e. The suspension 3 was separated into solid and liquid by vacuum filtration to obtain a solid slurry; f. The solid slurry was dried and then heated to 290-310 ° C and kept warm for 5-7h to obtain powder B. Ethanol was added to the powder B to dissolve and obtain a suspension 4. g. After the ruthenium acetylacetonate is dissolved in the ethanol solution, the suspension 4 is stirred at 94-98 ° C until the solvent is completely evaporated to obtain a powder C; h. The powder was gradually heated to 390-410°C and kept at this temperature for 5-7h to obtain Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst.

7. The method according to claim 6, characterized in that In step b, the working concentration of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier in the suspension 1 is 0.28-0.286 g / ml; In step c, in the suspension 2, the working concentration of the cerium nitrate hexahydrate is 0.034-0.037 g / ml.

8. The method according to claim 6, characterized in that The mass ratio of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier, cerium nitrate hexahydrate and ruthenium acetylacetonate added in the preparation of the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst is (17151-17154):(2520-2523):(3.15-4.98).

9. A Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst, characterized in that: Prepared by the method described in any one of claims 6 to 8.

10. Use of the (Fe-Cu)Mn2O4 spinel reforming catalyst carrier according to claim 1 and the Ru / CeO2 / (Fe-Cu)Mn2O4 reforming catalyst according to claim 9 in hydrothermal catalytic reforming to produce hydrogen.

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