High-stability ni@halbeta catalyst, preparation and application thereof

Abstract

The application discloses a high-stability Ni@HAlBeta catalyst and a preparation and application thereof. The catalyst is prepared by mixing and grinding with acetylacetone nickel and calcining and reducing, and takes dealuminated beta zeolite as a carrier. A silanol nest structure of the HAlBeta carrier forms a strong metal carrier interaction with Ni, and sintering of the Ni is inhibited. Dealuminization treatment reduces the acidity of the carrier, and formation of encapsulated carbon and graphitic carbon is inhibited. The catalyst shows excellent performance in hydrogen production by biomass gasification. The preparation process is simple, and the cost is low, and the catalyst is suitable for various agricultural and forestry waste raw materials, and provides an efficient catalyst scheme for industrialization of a biomass gasification and hydrogen-rich synthesis gas technology.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a highly stable nickel-based catalyst for the production of hydrogen-rich syngas from biomass gasification, and more particularly to a Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel, its preparation method, and its application. Background Technology

[0002] Against the backdrop of global energy transition, biomass gasification technology, as an important pathway to produce hydrogen-rich syngas from carbon-neutral resources, has broad application prospects. However, the tar produced during gasification can lead to pipeline blockage and equipment corrosion, reducing process efficiency and syngas quality. Therefore, catalysts are essential to enhance tar reforming and improve hydrogen yield. Nickel-based catalysts have become the mainstream choice for biomass gasification hydrogen production due to their high catalytic activity and low cost. However, they are prone to rapid deactivation in high-temperature reaction environments due to two core issues: first, Ni nanoparticles undergo Ostwald ripening and agglomeration (i.e., sintering), resulting in a reduction in the exposure of active sites; second, carbon deposits such as encapsulated carbon and graphitized carbon are generated during the reaction, covering active sites or blocking catalyst pores. These two deactivation mechanisms are interdependent and difficult to solve individually, severely limiting the industrial application of nickel-based catalysts.

[0003] Existing technologies have significant limitations in addressing the aforementioned problems: On the one hand, to suppress carbon deposition, additional metals (such as Ca, Mg, and Ru) are often used to reduce the acidity of the support, but this significantly increases the preparation cost and makes large-scale application impossible; on the other hand, to suppress sintering, defective supports such as CeO2 and Al2O3 are often used to anchor Ni particles, but Ce-based supports are expensive, and Al2O3 easily forms an inactive NiAl2O4 phase with Ni at high temperatures; at the same time, although traditional zeolite supports have high specific surface area and thermal stability, their high acidity easily induces the polymerization of aromatic compounds to form carbon deposits, and the metal dispersion is poor when Ni is loaded using conventional impregnation methods, making it impossible to fully utilize the defective sites of the support to achieve sintering suppression.

[0004] To address the aforementioned issues, dealubilized zeolites can reduce strong acid sites and generate silanol nests, providing anchoring points for metal particles. However, their application under high-temperature, steam-rich biomass gasification conditions has not been fully explored, and there is a lack of efficient Ni species loading strategies that can simultaneously leverage the structural advantages of dealubilized zeolites to achieve a synergistic effect of "anti-sintering + anti-coking." Therefore, developing a low-cost nickel-based catalyst that does not require precious metal doping and simultaneously solves the sintering and coking problems through synergistic design is a key requirement for promoting the industrialization of biomass gasification hydrogen production technology. Summary of the Invention

[0005] To address the technical shortcomings of existing nickel-based catalysts in biomass gasification hydrogen production, which cannot effectively suppress sintering and coking simultaneously, leading to insufficient stability, the primary objective of this invention is to provide a method for preparing a Ni@HAlBeta catalyst based on dealuded β-zeolite supported nickel. Through specific precursor selection, carrier dealuding modification, and process optimization, a synergistic effect of "silanol nesting for anti-sintering + low acidity for inhibiting coking + high dispersion through gas-phase diffusion" is achieved, simultaneously solving the two major deactivation problems and significantly improving the catalyst's catalytic performance and cycle stability.

[0006] Another object of the present invention is to provide a Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel prepared by the above preparation method.

[0007] Another object of the present invention is to provide the application of the above-mentioned Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel in the preparation of hydrogen-rich syngas.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel, comprising the following steps:

[0010] (1) β zeolite was dispersed in nitric acid aqueous solution, heated and stirred, filtered, washed with water and dried to obtain HAlBeta support with both silanol nest structure and low acidity.

[0011] (2) The HAlBeta support obtained in step (1) and nickel acetylacetone are ground and mixed, and then calcined to obtain NiO@HAlBeta precursor;

[0012] (3) The NiO@HAlBeta precursor obtained in step (2) is heated and reduced in a reducing atmosphere containing hydrogen, and then cooled to obtain a Ni@HAlBeta catalyst with nickel supported by dealuminated β zeolite.

[0013] In the method of the present invention, in step (1), β zeolite is treated with nitric acid to remove aluminum, and HAlBeta support with both silanol nest structure and low acidity is obtained; in step (3), after the NiO@HAlBeta precursor is reduced, Ni particles are anchored through silanol nest to enhance the interaction between metal support, and at the same time, the low acidity of the support inhibits the formation of carbon deposits, thereby achieving a synergistic stabilizing effect.

[0014] Preferably, the Si / Al ratio of the β zeolite in step (1) is 10 to 60:1; more preferably, it is 20:1.

[0015] Preferably, the concentration of the nitric acid aqueous solution in step (1) is 10-13 mol / L.

[0016] Preferably, the mass ratio of the β-zeolite in step (1) to the volume ratio of the nitric acid aqueous solution is 1g:8-12mL; more preferably, it is 1g:10mL.

[0017] Preferably, the heating and stirring temperature in step (1) is 80±5℃ and the time is 12±1h.

[0018] Preferably, the rotation speed of the heating and stirring in step (1) is 500±50 r / min.

[0019] Preferably, the water washing in step (1) is performed until the pH of the filtrate is approximately 7.

[0020] Preferably, the drying temperature in step (1) is 80±5℃ and the time is 12±1h.

[0021] Preferably, the HAlBeta support and nickel acetylacetone (Ni(acac)2) in step (2) are ground and mixed according to a theoretical Ni loading of 10±2wt%.

[0022] Preferably, the grinding time in step (2) is 1 ± 0.5 h.

[0023] Preferably, the calcination temperature in step (2) is 300±50℃ and the time is 6±1h.

[0024] Preferably, the calcination in step (2) is carried out in an air atmosphere.

[0025] Preferably, the heating rate of the calcination in step (2) is 10±5℃ / min.

[0026] Preferably, in the hydrogen-containing reducing atmosphere of step (3), the volume content of hydrogen is 10±2%; more preferably, the hydrogen-containing reducing atmosphere is an H2 / Ar mixed gas.

[0027] Preferably, the gas flow rate of the hydrogen-containing reducing atmosphere in step (3) is 50±10 mL / min.

[0028] Preferably, the temperature of the heating reduction reaction in step (3) is 800±50℃ and the time is 2±0.5h.

[0029] Preferably, the heating rate of the reduction reaction in step (3) is 10±5℃ / min.

[0030] Secondly, the present invention provides a Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel prepared by the above preparation method.

[0031] Thirdly, the present invention provides the application of the above-mentioned Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel in the preparation of hydrogen-rich syngas.

[0032] Fourthly, this invention provides a method for the catalytic preparation of hydrogen-rich syngas using a Ni@HAlBeta catalyst based on dealuminated β-zeolite-supported nickel, comprising the following steps:

[0033] A two-stage fixed-bed reaction system is adopted, with the upper stage being a biomass gasification stage and the lower stage being a catalyst reforming stage. After the biomass feedstock is dried and pulverized, it is placed in a basket in the gasification stage, and the catalyst is placed in the reforming stage in the lower stage. After the reaction temperature and water vapor stabilize, the basket carrying the biomass is sent into the gasification stage, where gasification and catalytic reforming reactions are carried out under carrier gas conditions. The gas is collected to obtain hydrogen-rich syngas.

[0034] Preferably, the vaporization temperature is 700±50℃.

[0035] Preferably, the temperature of the catalytic reforming reaction is 700–800°C.

[0036] Preferably, the molar ratio (S / C) of the water vapor and biomass carbon is 4 ± 0.5:1.

[0037] Preferably, the biomass includes at least one of sawdust, cotton stalks, bark, grapevines, and walnut shells.

[0038] Preferably, the mass ratio of biomass to catalyst is 1 ± 0.5:1.

[0039] Preferably, the carrier gas includes at least one of nitrogen, argon, and helium.

[0040] Preferably, the flow rate of the carrier gas is 50±10 mL / min.

[0041] Preferably, the time for both the gasification and catalytic reforming reactions is 50 ± 10 min.

[0042] Preferably, the biomass is obtained by drying and pulverizing biomass raw materials to 40-80 mesh.

[0043] More preferably, the drying temperature is 105±5℃ and the time is 12±1h.

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

[0045] (1) Low preparation cost and simple process: The catalyst is prepared by a simple mechanical grinding method, which is simple, easy to implement and highly reproducible.

[0046] (2) High catalytic activity: By utilizing the gas phase diffusion characteristics during the Ni(acac)2 roasting process, a high dispersion loading of Ni species is achieved, avoiding the problem of poor dispersion caused by the traditional wet impregnation method, forming small-scale nickel particles, which is beneficial to the tar cracking and catalytic conversion reaction in the biomass gasification process.

[0047] (3) Excellent anti-sintering performance: The silanol nest structure of the HAlBeta support interacts strongly with the Ni particles to anchor the Ni nanoparticles and inhibit their migration and aggregation.

[0048] (4) Outstanding anti-carbon deposition performance: The dealumination treatment significantly reduces the density of strong acid sites on the carrier, reduces the polymerization of aromatic compounds, and inhibits the formation of encapsulated carbon. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the preparation process of the Ni@HAlBeta catalyst for synergistically inhibiting sintering and carbon deposition, as described in this invention.

[0050] Figure 2 The images show the XRD patterns of the Ni@HAlBeta catalyst synthesized in Example 1 that synergistically inhibits sintering and carbon deposition, and the catalysts synthesized in Comparative Examples 1-3.

[0051] Figure 3 The images show the FTIR spectra of the Ni@HAlBeta catalyst synthesized in Example 1 that synergistically inhibits sintering and carbon deposition, and the catalysts synthesized in Comparative Examples 1-3.

[0052] Figure 4 The images show the H2-TPR diagrams of the NiO@HAlBeta catalyst synthesized in Example 1, which synergistically inhibits sintering and carbon deposition, and the unreduced catalysts synthesized in Comparative Examples 1-3.

[0053] Figure 5 The figures show the Ni@HAlBeta catalyst synthesized in Example 1 that synergistically inhibits sintering and carbon deposition, and the NH3-TPD of the catalysts synthesized in Comparative Examples 1-3.

[0054] Figure 6 These are TEM images of the Ni@HAlBeta catalyst synthesized in Example 1 that synergistically inhibits sintering and carbon deposition, and the catalysts synthesized in Comparative Examples 1-3.

[0055] Figure 7 This is a comparison chart of the gas production after 15 cycles of the Ni@HAlBeta catalyst synthesized in Example 1, which synergistically inhibits sintering and carbon deposition.

[0056] Figure 8 This is a comparison chart of the gas production of the Ni / Beta catalyst synthesized in Comparative Example 1 after 10 cycles.

[0057] Figure 9The graphs show the tar composition changes during the cycling process of the Ni@HAlBeta catalyst synthesized in Example 1, which synergistically inhibits sintering and carbon deposition, and the Ni / Beta catalyst synthesized in Comparative Example 1. Detailed Implementation

[0058] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0059] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.

[0060] raw material:

[0061] Commercial β-zeolite: Si / Al=20, industrial grade;

[0062] Nickel acetylacetone (Ni(acac)2): analytical grade, purity ≥99.0%;

[0063] Nitric acid: analytical grade, concentration 68 wt%;

[0064] Nickel nitrate (Ni(NO3)2•6H2O): analytical grade, purity ≥99.0%;

[0065] Biomass raw materials:

[0066] Raw material 1: Pear wood chips from Xinjiang (basic raw material), dried at 105℃ for 12 hours, pulverized and passed through a 40-80 mesh sieve. Industrial analysis: moisture 5.46wt%, volatile matter 77.30%, ash 2.30wt%, fixed carbon 14.94wt%; elemental analysis: C 45.4wt%, H 5.64wt%, N 0.84wt%, S 0.13wt%, O 47.99wt%.

[0067] Raw material 2: Cotton stalks from Xinjiang (extension raw material), pretreated the same as sawdust. Industrial analysis: moisture 6.89wt%, volatile matter 75.3wt%, ash 3.89wt%, fixed carbon 13.92wt%. Elemental analysis: C 44.74wt%, H 5.72wt%, N 1.35wt%, S 0.17wt%, O 48.02wt%.

[0068] Raw material 3: Walnut shells from Xinjiang (extension raw material), pretreatment same as sawdust, industrial analysis: moisture 5.01wt%, volatile matter 80.88wt%, ash 0.67wt%, fixed carbon 13.44wt%, elemental analysis: C 46.94wt%, H 5.86wt%, N 0.35wt%, S 0.15wt%, O 46.70wt%;

[0069] Carrier gas: N2 (purity ≥ 99.99%); Reducing gas: 10% H2 / Ar mixture (volume fraction, purity ≥ 99.99%).

[0070] Deionized water: conductivity ≤10μS / cm, prepared in the laboratory.

[0071] Example 1

[0072] A method for preparing a Ni@HAlBeta catalyst that synergistically inhibits sintering and carbon deposition includes the following steps:

[0073] (1) Preparation of HAlBeta carrier: Weigh 10g of commercial β zeolite and disperse it in 100mL of 13mol / L nitric acid aqueous solution. Stir vigorously at 80℃ and 500r / min for 12h. After the reaction is completed, filter and wash the precipitate with deionized water until the pH of the filtrate is ≈7. Dry at 80℃ for 12h to obtain HAlBeta carrier.

[0074] (2) Ni loading: Weigh 5g of HAlBeta support, add a certain mass of nickel acetylacetone (theoretical Ni loading 10wt%), grind for 1h until uniformly mixed to obtain a mixture;

[0075] (3) Calcination and activation: The mixture was placed in a muffle furnace and heated to 300°C at 10°C / min. It was then calcined for 6 hours in a static air atmosphere to obtain the NiO@HAlBeta precursor.

[0076] (4) Reduction treatment: The NiO@HAlBeta precursor was placed in a quartz tube reactor and a 10% H2 / Ar mixed gas (flow rate 50 mL / min) was introduced. The temperature was raised to 800℃ at a rate of 10℃ / min and reduced at a constant temperature for 2 hours. The catalyst was then naturally cooled to room temperature to obtain a Ni@HAlBeta catalyst that synergistically inhibits sintering and carbon deposition.

[0077] Comparative Example 1

[0078] Same as Example 1, except that:

[0079] In step (1), the carrier is not subjected to acid treatment for dealuminization, and the carrier is named Beta;

[0080] In step (2), 5g of Beta support was weighed and added to a 0.17mol / L nickel nitrate solution. The mixture was stirred and impregnated for 12h (the theoretical Ni loading was controlled at 10wt%). The impregnation solution was then placed in an 80℃ forced-air drying oven and dried for 12h to obtain a solid powder.

[0081] Step (3) Calcination and activation: The solid powder is placed in a muffle furnace and heated to 300°C at 10°C / min. It is then calcined for 6 hours in a static air atmosphere to obtain the NiO / Beta precursor.

[0082] Step (4) Reduction treatment: Place the NiO / Beta precursor in a quartz tube reactor, introduce 10% H2 / Ar mixed gas (flow rate 50 mL / min), raise the temperature to 800℃ at a rate of 10℃ / min, reduce at a constant temperature for 2 hours, and cool naturally to room temperature to obtain the Ni / Beta catalyst.

[0083] Comparative Example 2

[0084] Same as Example 1, except that:

[0085] In step (1), the carrier is not subjected to acid treatment for dealuminization, and the carrier is named Beta;

[0086] In step (2), 5g of Beta carrier was weighed, a certain mass of nickel acetylacetone (theoretical Ni loading 10wt%) was added, and the mixture was ground for 1 hour until it was uniformly mixed to obtain a mixture;

[0087] Step (3) Calcination and activation: The mixture is placed in a muffle furnace and heated to 300°C at 10°C / min. It is then calcined in a static air atmosphere for 6 hours to obtain the NiO@Beta precursor.

[0088] Step (4) Reduction treatment: Place the NiO@Beta precursor in a quartz tube reactor, introduce 10% H2 / Ar mixed gas (flow rate 50 mL / min), raise the temperature to 800℃ at a rate of 10℃ / min, reduce at a constant temperature for 2 hours, and cool naturally to room temperature to obtain the Ni@Beta catalyst.

[0089] Comparative Example 3

[0090] Same as Example 1, except that:

[0091] In step (2), 5g of HAlBeta support was weighed and added to a 0.17mol / L nickel nitrate solution. The solution was stirred and impregnated for 12h (the theoretical Ni loading was controlled at 10wt%). The impregnation solution was then placed in an 80℃ forced-air drying oven and dried for 12h to obtain a solid powder.

[0092] Step (3) Calcination and activation: The solid powder is placed in a muffle furnace and heated to 300°C at 10°C / min. It is then calcined for 6 hours in a static air atmosphere to obtain the NiO / HAlBeta precursor.

[0093] Step (4) Reduction treatment: Place the NiO / HAlBeta precursor in a quartz tube reactor, introduce 10% H2 / Ar mixed gas (flow rate 50 mL / min), raise the temperature to 800℃ at a rate of 10℃ / min, reduce at a constant temperature for 2 hours, and cool naturally to room temperature to obtain the Ni / HAlBeta catalyst.

[0094] Comparative Example 4

[0095] Same as Example 1, except that:

[0096] In step (2), weigh 5g of HAlBeta support, add a certain mass of nickel nitrate (theoretical Ni loading 10wt%), and grind for 1h until the mixture is uniform;

[0097] Step (3) Calcination and activation: The mixture was placed in a muffle furnace and heated to 300°C at 10°C / min. It was then calcined for 6 hours in a static air atmosphere to obtain the NiO / HAlBeta-YM precursor.

[0098] Step (4) Reduction treatment: The NiO / HAlBeta-YM precursor was placed in a quartz tube reactor and a 10% H2 / Ar mixed gas (flow rate 50 mL / min) was introduced. The temperature was increased to 800℃ at a rate of 10℃ / min and reduced at a constant temperature for 2 hours. The catalyst was then naturally cooled to room temperature to obtain the Ni / HAlBeta-YM catalyst.

[0099] Comparative Example 5

[0100] Same as Example 1, except that:

[0101] In step (2), 5g of HAlBeta support was weighed and added to a 0.17mol / L nickel acetylacetone solution. The solution was stirred and impregnated for 12h (the theoretical Ni loading was controlled at 10wt%). The impregnation solution was then placed in an 80℃ forced-air drying oven and dried for 12h to obtain a solid powder.

[0102] Step (3) Calcination and activation: The solid powder is placed in a muffle furnace and heated to 300°C at 10°C / min. It is then calcined for 6 hours in a static air atmosphere to obtain the NiO / HAlBeta-JZ precursor.

[0103] Step (4) Reduction treatment: The NiO / HAlBeta-JZ precursor was placed in a quartz tube reactor and a 10% H2 / Ar mixed gas (flow rate 50 mL / min) was introduced. The temperature was increased to 800℃ at a rate of 10℃ / min and reduced at a constant temperature for 2 hours. The catalyst was then naturally cooled to room temperature to obtain the Ni / HAlBeta-JZ catalyst.

[0104] Figure 2 XRD showed that the nickel in the samples after catalyst reduction in Example 1 and Comparative Examples 1-3 existed mainly in the form of elemental nickel.

[0105] Figure 3 FTIR indicates that Beta zeolite has a high viscosity at 900-1000 cm⁻¹ -1 There was no obvious absorption band within the range, while HAlBeta showed an absorption band at 956 cm⁻¹.-1 A distinct absorption band is observed at this location, attributed to the silanol nests formed during the dealumination of β-zeolite. Furthermore, this absorption band significantly weakens after loading Ni(acac)₂ and Ni(NO₃)₂•6H₂O onto HAlBeta, indicating that Ni species occupy the silanol nests. Additionally, at 1630 cm⁻¹... -1 and 3467 cm -1 The absorption bands at these locations correspond to the bending vibrations of hydroxyl groups and the stretching vibrations of surface Si-OH, respectively, which further confirms this interaction.

[0106] Figure 4 H2-TPR showed that the catalyst precursors of Example 1 and Comparative Examples 1-3 all exhibited H2 consumption peaks at different reduction temperatures, indicating differences in the interaction between nickel species and the support. For the catalyst precursor of Comparative Example 1, the reduction spectrum showed a bimodal characteristic: a low-temperature peak at 266℃ attributed to the reduction of large "free" NiO crystals on the surface, while a broad high-temperature reduction peak at 373℃ corresponded to the reduction of small-sized NiO nanoparticles. This indicates that the nickel particle distribution in the catalyst prepared by the impregnation method is uneven and the metal-support strong interaction (MSI) is weak. The catalyst precursor of Comparative Example 2 exhibited a single broad reduction peak in the range of 260-420℃, with the maximum H2 consumption occurring at 370℃, but its limited interaction with the support led to sintering of nickel particles during reduction. The high-temperature reduction peak of the catalyst of Example 1 mainly appeared at 392℃, and a hydrogen reduction peak also appeared at 480℃. This indicates that the presence of silanol nests enhanced the MSI.

[0107] Figure 5 NH3-TPD analysis revealed that the catalysts of Comparative Example 1 and Comparative Example 2 exhibited three distinct ammonia desorption peaks at approximately 163 °C, 400 °C, and 506 °C. The first two peaks corresponded to weak and strong acid sites, respectively, while the third peak was attributed to extra-framework aluminum. In contrast, the catalysts of Example 1 and Comparative Example 3 showed a significant decrease in acidity, manifested by the disappearance of the strong acid peak near 500 °C and the shift of the other two peaks to lower temperatures. This observation confirms that the removal of framework aluminum from the zeolite leads to a significant reduction in the density of acidic sites in the catalyst.

[0108] Figure 6 TEM showed that the Ni particle size in Example 1 was only 5.3 nm. Due to the lack of anchoring points, Comparative Examples 1 and 2 exhibited severe sintering. Elemental mapping confirmed that Comparative Examples 1 and 3 suffered from uneven Ni dispersion due to the conventional impregnation method (d and h in the figure), while the Ni(acac)2 loading method achieved a highly uniform metal distribution in both Example 1 and Comparative Example 2.

[0109] Example 2

[0110] Application of a Ni@HAlBeta catalyst that synergistically inhibits sintering and coking in biomass gasification for syngas production

[0111] Experimental procedure for producing hydrogen-rich syngas from biomass gasification: Weigh 0.5g of pear wood sawdust powder (40-80 mesh) and place it in a basket (above the gasification section). Place the catalysts prepared in Example 1 and Comparative Examples 1-3 in the catalytic section, respectively, with a catalyst / biomass mass ratio of 1:1. Purge with N2 (flow rate 50mL / min) for 60min to remove air. Heat the gasification section to 700℃ and the catalytic section to 750℃. Evaporate deionized water into steam using a jet pump, controlling the steam / carbon (S / C) molar ratio to 4. Introduce the steam and N2 carrier gas into the reactor. After the temperature stabilizes, quickly send the basket carrying the biomass powder into the gasification section. React for 50min and collect the product gas using a gas sampling bag. Analyze the product components using gas chromatography.

[0112] Table 1. Gas production effect of reactions with and without catalyst.

[0113]

[0114] The catalytic effects are shown in Table 1. The Ni@HAlBeta catalyst produces hydrogen-rich syngas and has a higher tar conversion rate than other comparative catalysts.

[0115] Example 3

[0116] To verify the catalyst's recyclability, the following cycle test can be conducted, with specific experimental steps as follows:

[0117] The Ni@HAlBeta catalyst obtained in Example 1 was used in the experiment, and the gasification reaction conditions were the same as in Example 2. After each reaction, the catalyst was not removed, but 0.5 g of sawdust was added again, and the above experimental steps were repeated for a total of 15 cycles. The results are as follows:

[0118] Table 2. Catalytic gas production effect of Ni@HAlBeta catalyst recycling

[0119]

[0120] Table 2 shows that after 15 cycles, the hydrogen yield stabilized at approximately 24 mmol / g. biomass The gas production rate remained at a high level throughout the cycle, indicating that the Ni@HAlBeta catalyst has good stability.

[0121] Depend on Figure 9 The changes in tar composition during the cycle process revealed that after 15 cycles, the proportion of tar components on the Ni@HAlBeta catalyst remained essentially unchanged, indicating its high stability during tar cracking.

[0122] Table 3. Sintering and carbon deposition of Ni@HAlBeta catalyst after recycling.

[0123]

[0124] Table 3 shows that after 15 cycles, the Ni particles in the Ni@HAlBeta catalyst remained at 5.3-5.8 nm, without sintering, and the amount of carbon deposited was low.

[0125] Comparative Example 6

[0126] The Ni / Beta catalyst obtained in Comparative Example 1 was used in the experiment, and the gasification reaction conditions were the same as in Example 2. After each reaction, the catalyst was not removed, but 0.5 g of sawdust was added again, and the above experimental steps were repeated for a total of 10 cycles. The results are as follows:

[0127] Table 4. Catalytic gas production effect of Ni / Beta catalyst recycling

[0128]

[0129] As shown in Table 4, the Ni / Beta catalyst was almost deactivated in the 7th cycle, because after the 7th cycle, the hydrogen concentration and yield were almost the same as those without the catalyst.

[0130] Table 5. Sintering and carbon deposition of Ni / Beta catalyst after recycling.

[0131]

[0132] As shown in Table 5, after 10 cycles, the Ni / Beta catalyst underwent severe sintering and a significant increase in carbon deposits.

[0133] Example 4

[0134] The gasification reaction conditions were the same as in Example 2, except that the Ni@HAlBeta catalyst, which synergistically inhibits sintering and carbon deposition as in Example 1, was used, and various agricultural, forestry, and livestock organic wastes, including pear wood chips, cotton stalks, bark, grapevines, and walnut shells, were used as gasification feedstocks. The catalytic gas production effect is shown in Table 6.

[0135] Table 6. Catalytic gasification effect of Ni@HAlBeta catalyst on different biomass waste feedstocks

[0136]

[0137] Table 6 shows that the Ni@HAlBeta catalyst exhibits good performance under different raw materials, indicating that the Ni@HAlBeta catalyst that synergistically inhibits sintering and carbon deposition has universality.

[0138] Example 5

[0139] The gasification reaction conditions were the same as in Example 2, except that the catalytic temperature was 700°C. The catalytic gas production effect is shown in Table 7.

[0140] Table 7. Catalytic gas production effect of Ni@HAlBeta catalyst in the reaction under the conditions of Example 5.

[0141]

[0142] As shown in Table 7, a catalytic temperature that is too low will lead to a decrease in catalyst performance. Therefore, the catalytic temperature should be higher than 700℃.

[0143] Example 6

[0144] The gasification reaction conditions were the same as in Example 2, except that the catalytic temperature was 800°C. The catalytic gas production effect is shown in Table 8.

[0145] Table 8. Catalytic gas production effect of Ni@HAlBeta catalyst in the reaction under the conditions of Example 6.

[0146]

[0147] As shown in Table 8, excessively high catalytic temperatures (800℃) will inhibit the water vapor reaction, therefore the optimal catalytic temperature is 750℃.

[0148] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel, characterized in that, Includes the following steps: (1) β zeolite was dispersed in nitric acid aqueous solution, heated and stirred, filtered, washed with water and dried to obtain HAlBeta support with both silanol nest structure and low acidity. (2) The HAlBeta support obtained in step (1) and nickel acetylacetone are ground and mixed, and then calcined to obtain NiO@HAlBeta precursor; (3) The NiO@HAlBeta precursor obtained in step (2) is heated and reduced in a reducing atmosphere containing hydrogen, and then cooled to obtain a Ni@HAlBeta catalyst with nickel supported by dealuminated β zeolite.

2. The preparation method according to claim 1, characterized in that, The Si / Al ratio of the β-zeolite in step (1) is 10 to 60:1; more preferably 20:

1. And / or, the concentration of the nitric acid aqueous solution in step (1) is 10–13 mol / L; And / or, the mass ratio of the β-zeolite in step (1) to the volume ratio of the nitric acid aqueous solution is 1 g: 8 to 12 mL; more preferably, it is 1 g: 10 mL; And / or, the heating and stirring temperature in step (1) is 80±5℃ and the time is 12±1h.

3. The preparation method according to claim 1 or 2, characterized in that, In step (2), the HAlBeta support and nickel acetylacetone are ground and mixed according to a theoretical Ni loading of 10±2wt%. And / or, the grinding time in step (2) is 1 ± 0.5 h.

4. The preparation method according to claim 1 or 2, characterized in that, The calcination temperature in step (2) is 300±50℃ and the time is 6±1h; And / or, the calcination in step (2) is carried out in an air atmosphere; And / or, the heating rate of the calcination in step (2) is 10±5℃ / min.

5. The preparation method according to claim 1 or 2, characterized in that, In step (3), the hydrogen-containing reducing atmosphere has a hydrogen volume content of 10±2%; more preferably, the hydrogen-containing reducing atmosphere is an H2 / Ar mixed gas. And / or, the gas flow rate of the hydrogen-containing reducing atmosphere in step (3) is 50±10 mL / min; And / or, the temperature of the heating reduction reaction in step (3) is 800±50℃ and the time is 2±0.5h; And / or, the heating rate of the reduction reaction in step (3) is 10 ± 5 °C / min.

6. A Ni@HAlBeta catalyst based on dealuminated β-zeolite supported nickel prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the Ni@HAlBeta catalyst based on dealubilized β-zeolite supported nickel as described in claim 6 in the preparation of hydrogen-rich syngas.

8. A method for catalytically preparing hydrogen-rich syngas using a Ni@HAlBeta catalyst based on dealuminolite-supported nickel as described in claim 6, characterized in that, Includes the following steps: A two-stage fixed-bed reaction system is adopted, with the upper stage being a biomass gasification stage and the lower stage being a catalyst reforming stage. After the biomass feedstock is dried and pulverized, it is placed in a basket in the gasification stage, and the catalyst is placed in the reforming stage in the lower stage. After the reaction temperature and water vapor stabilize, the basket carrying the biomass is sent into the gasification stage, where gasification and catalytic reforming reactions are carried out under carrier gas conditions. The gas is collected to obtain hydrogen-rich syngas.

9. The method according to claim 8, characterized in that, The biomass includes at least one of sawdust, cotton stalks, bark, grapevines, and walnut shells; And / or, the mass ratio of the biomass to the catalyst is 1 ± 0.5:

1.

10. The method according to claim 8, characterized in that, The carrier gas includes at least one of nitrogen, argon and helium; And / or, the flow rate of the carrier gas is 50±10 mL / min; And / or, the time for the gasification and catalytic reforming reaction is 50 ± 10 min; And / or, the temperature of the vaporization is 700±50℃; And / or, the temperature of the catalytic reforming reaction is 700–800°C; And / or, the molar ratio of water vapor to biomass carbon is 4 ± 0.5:1.

Images