Method for hydrogen production by alcohol liquid phase reforming

Abstract

The present application relates to a kind of alcohol liquid phase reforming hydrogen production method, alcohol substance is under the action of alcohol liquid phase reforming hydrogen production catalyst, carries out liquid phase reforming hydrogen production, the alcohol substance is selected from one or several in C1-C10 monohydric alcohol, polyhydric alcohol;The alcohol liquid phase reforming hydrogen production catalyst is supported catalyst with carbon coating layer, which is composed of carrier, carbon coating layer, active metal component and optional adjuvant.The method provided by the present application has the characteristics of high alcohol conversion rate, high hydrogen selectivity and long service life.

Description

Technical Field

[0001] This invention relates to an alcohol-based liquid-phase reforming hydrogen production catalyst, its preparation method, and its application method. Background Technology

[0002] Currently, hydrogen production through liquid-phase reforming of alcohols using highly renewable feedstocks is gaining popularity. Biomass is a highly renewable resource, and its conversion into hydrogen involves two processes: generating liquid-phase hydrocarbons from biomass and then reforming them to produce H2 and CO2. The resulting CO2 can be recycled back into the environment and absorbed by plants to produce more biomass, while H2 can be used for various purposes, such as as a hydrogen source for fuel cells, in hydrogenation processes, and in internal combustion engines. Therefore, to make green hydrogen production and the industrial application of green hydrogen sources feasible, a more efficient reforming process needs to be developed.

[0003] Alcohol reforming for hydrogen production is currently mainly classified into two categories: steam reforming and liquid-phase reforming. Compared with traditional hydrocarbon reforming for hydrogen production via gas-phase reforming, liquid-phase reforming has many advantages: First, liquid-phase reforming does not require the vaporization of water and oxygen-containing hydrocarbons, reducing a significant amount of energy. Second, the oxygen-containing compounds dissolved in the aqueous phase are non-flammable, non-toxic, or low-toxic, and can be safely stored and handled. Third, the temperature and pressure of the liquid-phase reforming reaction are favorable for water-gas reactions, so only a small amount of CO is produced while producing hydrogen in a single chemical reactor. Finally, the pressure range used in liquid-phase reforming technology (generally 1.5-4 MPa) allows for more efficient purification of hydrogen-rich tail gas using pressure swing adsorption (PSA) or membrane separation technologies, and CO2 can also be effectively separated.

[0004] Therefore, liquid-phase reforming of alcohols has become a research hotspot in recent years. Methanol, ethylene glycol, glycerol, and glucose, which are polyols with hydroxyl groups attached to each carbon atom, have received the most attention.

[0005] On the other hand, in recent years, with the increasing demand for environmental protection, the efficient and clean utilization of coal has received great attention. Coal indirect liquefaction to synthesize oil can significantly improve the quality of coal utilization, reduce pollution, and is also one of the important ways to solve my country's oil shortage. The Fischer-Tropsch reaction is the core reaction of coal indirect liquefaction. In addition to hydrocarbons, the Fischer-Tropsch reaction also produces various oxygenated organic compounds, such as alcohols, acids, aldehydes, and ketones, while generating a large amount of water. For every ton of oil produced, approximately 1.3 tons of wastewater are generated. As of 2017, the national Fischer-Tropsch synthesis capacity was close to 10 million tons per year. With the government's encouragement of clean coal utilization policies, many new plants are under preparation or construction. By 2020, the Fischer-Tropsch synthesis capacity will approach 30 million tons per year. Therefore, nearly 40 million tons of wastewater per year will need to be treated at that time. This wastewater contains approximately 5% to 10% oxygenated organic compounds, including C1 to C2 compounds. 10 It contains alcohols, acids, aldehydes, and ketones. Fischer-Tropsch synthesis wastewater has a low pH (pH=3.0), is highly corrosive, and is difficult to treat, falling into the category of recalcitrant organic wastewater.

[0006] If biological methods are used to treat Fischer-Tropsch synthesis wastewater, alkali needs to be added during the treatment process to neutralize the acidity of the water, thereby introducing a large amount of salts. This increases the risk of pipeline blockage due to salt scale and also increases the risk of excessive salt content in the reclaimed water. Nitrogen and phosphorus salts also need to be added to provide nutrients for bacteria, and a large amount of sludge needs to be treated. Furthermore, the aeration tank requires a high volumetric load, resulting in significant land area, initial investment, and operating costs. In addition, distillation separation is energy-intensive, and the remaining wastewater after distillation is still difficult to treat biologically.

[0007] Currently, the main methods for treating the aqueous phase of Fischer-Tropsch synthesis reported both domestically and internationally are various distillation and distillation techniques, or a combination of membrane separation, extraction, and anaerobic / aerobic biochemical treatment processes.

[0008] CN105923889A proposes a method for treating Fischer-Tropsch synthesis wastewater. The method involves adjusting the pH of the wastewater using a micro-electrolysis process, followed by anaerobic degradation to degrade the organic matter. This method helps reduce the introduction of scaling ions. The coupled treatment of Fischer-Tropsch synthesis wastewater using the micro-electrolysis process and the anaerobic degradation process helps reduce the footprint of the treatment device and lower the treatment cost.

[0009] US6887908 discloses a method for treating Fischer-Tropsch reaction wastewater, which uses a combination of evaporation and oxidation to remove organic oxygenated compounds from the water.

[0010] CN103011373B proposes a method for utilizing Fischer-Tropsch wastewater, which uses ammonia-containing wastewater to neutralize the acidity of Fischer-Tropsch wastewater, and then uses it to prepare coal-water slurry, thereby achieving the reuse of both types of wastewater.

[0011] CN104150670B proposes a Fischer-Tropsch wastewater treatment method that employs a dealcoholization system and an extraction system. The dealcoholization tower is used to remove alcohols from the Fischer-Tropsch wastewater, and then the extraction system is used to extract organic acids from the dealcoholization wastewater, thereby improving the recovery and utilization rate of organic matter in the Fischer-Tropsch wastewater. Summary of the Invention

[0012] The purpose of this invention is to provide an alcohol liquid-phase reforming hydrogen production catalyst, its preparation method, and its application method to improve the conversion rate of alcohols.

[0013] The alcohol liquid-phase reforming hydrogen production catalyst provided by this invention is a supported catalyst with a carbon coating layer, which consists of a support, a carbon coating layer, an active metal component, and optional promoters. The support is an inorganic oxide, and the active metal component is a Group VIII metal component. Based on the overall catalyst, the mass fraction of carbon in the carbon coating layer is 0.01%-5%, and the mass fraction of the active metal component, calculated as oxide, is 0.01%-50%.

[0014] In a preferred embodiment, the support is selected from one or more of magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, zirconium oxide, titanium oxide, zinc oxide, lanthanum oxide, cerium oxide, and alumina-silicon oxide. More preferably, magnesium oxide and / or aluminum oxide are used. The percentage of each support component by its total mass can be 0%-100%.

[0015] In this invention, the optional additive refers to an additive that is not an essential component and may or may not be present. The additive is selected from one or more combinations of elements of Group IIIA, IVA, VA, IB, IIB, IIB, IIIB, IVB, VB, VIB, VIIB or their oxides, lanthanide metals or their metal oxides, actinide metals or their metal oxides, and the mass fraction of the additive is 0-20% based on the total catalyst.

[0016] In one preferred embodiment of the present invention, the active metal component is a Group VIII noble metal active component, and the mass fraction of the active metal component, based on the entire catalyst and calculated as oxide, is 0.01%-20%.

[0017] In another preferred embodiment of the present invention, the active metal component is a Group VIII non-precious metal active component, namely selected from one or more of iron, cobalt, and nickel, and the mass fraction of the active metal component, based on the catalyst as a whole and calculated as oxides, is 0.05%-48%.

[0018] In this invention, the carbon coating layer is preferably an oligolayer graphene layer with 1-20 graphene layers, and more preferably 2-8 graphene layers.

[0019] The carbon coating layer has two different implementations in this invention, depending on the core it coats. One implementation is as follows: a carrier serves as the core, the carbon coating layer coats the core, and the active metal component and optional additives are loaded onto the carbon coating layer.

[0020] Another implementation involves using a carrier loaded with an active metal component and optional additives as the core, with the carbon coating layer covering the core.

[0021] The present invention also provides a method for preparing the above-mentioned alcohol liquid-phase reforming hydrogen production catalyst, and there are different implementation methods depending on the carbon coating layer and the core being coated.

[0022] One method for preparing an alcohol-based liquid-phase reforming hydrogen production catalyst includes:

[0023] (1) Inorganic oxide powder and deionized water are mixed, with the mass ratio of deionized water to inorganic oxide powder being 5:1-30:1. After ultrasonic stirring for 1-10 hours, the mixture is heated and kept boiling for 5-40 hours. The resulting mixture is filtered and dried, and then heated at 300-600℃ for 1-10 hours to obtain carrier powder.

[0024] (2) Place the carrier powder obtained in step (1) into a tube furnace, and introduce dilution gas into the furnace at a flow rate of 50 ml / min-10000 ml / min. The dilution gas is selected from one or more of Ar, He, and N2. Heat the furnace to 700-1000℃, and introduce methane at a flow rate of 1 ml / min-100 ml / min for 0.5 min-30 min. Stop introducing methane and maintain the flow rate of dilution gas at 50 ml / min-100000 ml / min until the temperature drops to room temperature to obtain carrier powder with carbon coating. The absolute pressure in the tube furnace is 0.005 kPa-20 kPa.

[0025] (3) The carbon-coated support powder obtained in step (2) is impregnated with a Group VIII active metal salt solution and an optional auxiliary salt solution, and then dried and calcined to obtain an alcohol liquid-phase reforming hydrogen production catalyst.

[0026] In this invention, the inorganic oxide powder is preferably selected from one or more of magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, zirconium oxide, titanium oxide, zinc oxide, lanthanum oxide, cerium oxide, and aluminum oxide-silicon oxide powder; the average particle size of the inorganic oxide powder is 0.1um-100um, preferably 1um-50um.

[0027] In this invention, the optional additive refers to an additive that is not an essential component. Preferably, the additive is selected from one or more combinations of elements of Group IIIA, IVA, VA, IB, IIB, IIIB, IVB, VB, VIB, VIIB or their oxides, lanthanide metals or their oxides, and actinide metals or their oxides.

[0028] Another method for preparing an alcohol-based liquid-phase reforming catalyst for hydrogen production includes:

[0029] (1) Inorganic oxide powder and deionized water are mixed, with the mass ratio of deionized water to inorganic oxide powder being 5:1-30:1. After ultrasonic stirring for 1-10 hours, the mixture is heated and kept boiling for 5-40 hours. The resulting mixture is filtered and dried, and then heated at 300-600℃ for 1-10 hours to obtain carrier powder.

[0030] (2) The carrier powder obtained in step (1) is impregnated with a Group VIII active metal salt solution and an optional auxiliary salt solution, and then dried, calcined, and reduced to obtain a carrier powder loaded with active metal.

[0031] (3) Place the carrier powder with active metal loaded in step (2) into a tube furnace, and introduce dilution gas into the furnace at a flow rate of 50 ml / min-10000 ml / min. The dilution gas is selected from one or more of Ar, He, and N2. Heat the furnace to 700-1000℃, and introduce methane at a flow rate of 1 ml / min-100 ml / min for 0.5 min-30 min. Stop introducing methane and maintain the flow rate of dilution gas at 50 ml / min-100000 ml / min until the temperature drops to room temperature. The absolute pressure in the tube furnace is 0.005 kPa-20 kPa to obtain an alcohol liquid-phase reforming hydrogen production catalyst.

[0032] In this invention, the inorganic oxide powder is preferably selected from one or more of magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, zirconium oxide, titanium oxide, zinc oxide, lanthanum oxide, cerium oxide, and aluminum oxide-silicon oxide powder; the average particle size of the inorganic oxide powder is 0.1um-100um, preferably 1um-50um.

[0033] In this invention, the optional additive refers to an additive that is not a necessary component. Preferably, the additive is selected from one or more combinations of elements of Group IIIA, IVA, VA, IB, IIB, IIIB, IVB, VB, VIB, VIIB or their oxides, lanthanide metals or their metal oxides, and actinide metals or their metal oxides.

[0034] In a preferred embodiment, the reduction in step (2) is carried out in a hydrogen atmosphere for a reduction time of 4-24 hours and a reduction temperature of 300-420°C.

[0035] In this invention, the number of graphene layers is controlled by adjusting different methane flow rates and the duration of methane introduction.

[0036] In this invention, the impregnation method is a conventional method, such as pore saturation impregnation, excess liquid impregnation, and spray impregnation. The Group VIII metal component and optional additives, one or more of which can be introduced individually, or in pairs or all three simultaneously. When the impregnation is a step-by-step impregnation, there is no restriction on the order in which the impregnation solution impregnates the carrier. Although not mandatory, a drying step is preferably included after each impregnation. The drying conditions include: a drying temperature of 100-210°C, preferably 120-190°C, and a drying time of 1-6 hours, preferably 2-4 hours.

[0037] The present invention also provides a method for applying the above-mentioned alcohol liquid-phase reforming hydrogen production catalyst, wherein the catalyst is applied in the liquid-phase reforming hydrogen production process of alcohol substances, and the alcohol substances are selected from one or more of C1-C10 monohydric alcohols and polyhydric alcohols.

[0038] Preferably, the polyol is selected from one or more of ethylene glycol, glycerol, sorbitol, and glucose.

[0039] Under preferred conditions, the reaction conditions for hydrogen production from alcohols via liquid-phase reforming are: reaction temperature of 180℃-280℃, pressure of 1.1MPa-7.0MPa, and volume hourly space velocity of 0.1-15h⁻¹. -1 The buffer gas is nitrogen, and the gas-liquid ratio during feeding is 0-800. The gas-liquid ratio refers to the ratio of the volume of gas to the volume of liquid under standard conditions.

[0040] In one embodiment of the present invention, the catalyst is used in the Fischer-Tropsch synthesis wastewater treatment process.

[0041] The Fischer-Tropsch synthesis wastewater is derived from water produced by the Fischer-Tropsch synthesis reaction. The Fischer-Tropsch synthesis wastewater contains C1-C10 alcohols, acids, aldehydes, and ketones, and the total mass fraction of oxygenated organic matter in the Fischer-Tropsch synthesis wastewater is 0.5% to 30%.

[0042] In another embodiment of the present invention, the catalyst is used in the biomass liquid-phase reforming catalytic hydrogen production process.

[0043] In existing technologies, conventional supports such as magnesium oxide and aluminum oxide suffer significant instability when subjected to prolonged immersion in hot water or when localized vaporization phase transitions occur in the alcohol liquid-phase feedstock during process parameter adjustments, thereby reducing catalyst lifespan. This invention utilizes two different oligolayer graphene coating methods to protect the support and catalyst structure from damage, extending catalyst lifespan while simultaneously enhancing the conversion rate of alcohols through the electronic conductivity characteristics of graphene.

[0044] The catalyst of this invention is used in the liquid-phase reforming process of alcohols to produce hydrogen, and has the characteristics of high conversion rate of alcohols, high hydrogen selectivity and long service life.

[0045] The catalyst provided by this invention, when applied in the treatment of Fischer-Tropsch synthesis wastewater, significantly improves the conversion rate of organic matter and hydrogen selectivity in the wastewater, and greatly extends the catalyst's lifespan. It enables a total carbon conversion rate of up to 100% and a hydrogen selectivity of up to 85% in the wastewater. After 2000 hours of continuous reaction, no significant deactivation of the catalyst was observed. Attached Figure Description

[0046] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0047] Figure 1 This is a graph showing the results of the catalyst lifetime test in Example 25.

[0048] Figure 2 This is a TEM image of the catalyst from Example 2.

[0049] Figure 3 This is a TEM image of the catalyst in Example 10. Detailed Implementation

[0050] The following embodiments will further illustrate the present invention, but the scope of protection of the present invention is not limited to these embodiments.

[0051] The surface morphology of the catalyst was characterized by high-resolution transmission electron microscopy (HRTEM). The HRTEM used was a Tecnai G. 2 The F20 (FEI Corporation, USA) was tested under the following conditions using a high-resolution transmission electron microscope: accelerating voltage of 200 kV.

[0052] Example 1

[0053] 10.0 g of magnesium oxide powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. The magnesium oxide powder was placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the furnace at 0.02 MPa. After heating to 900°C and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. The methane introduction was then stopped, and natural cooling was immediately initiated. Graphene is grown on the surface of magnesium oxide. The resulting product is added dropwise with distilled water until it is initially wetted, and the volume of water consumed is recorded. Then, based on a Pt content (calculated as oxide) of 3.0% by weight of the total catalyst mass, a tetraammineplatinum nitrate impregnation solution is prepared. Graphene@magnesium oxide is impregnated with this solution until initially wetted, allowed to stand for 8 hours, dried at 120°C for 4 hours, and then calcined in a muffle furnace at 450°C for 4 hours to obtain the final product. Before use, the catalyst needs to be reduced at 400°C in a hydrogen atmosphere for 12 hours.

[0054] Example 2

[0055] 10.0 g of magnesium oxide powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. The magnesium oxide powder was placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the furnace at 0.02 MPa. After heating to 900°C and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. The methane introduction was then stopped, and natural cooling was immediately initiated. Graphene grew on the magnesium oxide surface. The resulting product was added dropwise with distilled water until initially wetted, and the volume of water consumed was recorded. A nickel nitrate impregnation solution was prepared based on a Ni content (based on oxides) of 25% by weight of the total catalyst mass. Graphene@magnesium oxide was impregnated with this solution until initially wetted, allowed to stand for 8 hours, dried at 120°C for 4 hours, and then calcined in a muffle furnace at 450°C for 4 hours to obtain the final product. The catalyst needs to be reduced for 12 hours in a hydrogen atmosphere at 400°C before use.

[0056] Figure 2 TEM image of the alcohol liquid-phase reforming hydrogen production catalyst prepared in Example 2. From... Figure 2 It can be seen that the catalyst has a support as its core, and the carbon coating layer covers the core, with the active metal component nickel oxide loaded on the carbon coating layer.

[0057] Example 3

[0058] Mix 5.0g of magnesium oxide powder and 5.0g of aluminum oxide powder, then add 100.0g of deionized water and mix. Stir ultrasonically for 2 hours. Pour the mixture into a reflux condenser and boil continuously for 24 hours. After filtration, heat the product in a 500℃ furnace for 5 hours to completely remove moisture. Place the magnesium oxide powder in a CVD tube furnace and purge with Ar gas to maintain the absolute pressure in the furnace at 0.02MPa. After heating to 900℃ and stabilizing for 10 minutes, introduce methane at a flow rate of 5ml / min for 5 minutes, then stop the methane flow and immediately begin natural cooling. Graphene is grown on the surface of magnesium oxide. The resulting product is added dropwise with distilled water until it is initially wetted, and the volume of water consumed is recorded. Then, based on a Ni content (calculated as oxide) of 25% by weight of the total catalyst mass, a nickel nitrate impregnation solution is prepared. This solution is used to impregnate graphene@magnesium oxide@aluminum oxide until initially wetted, allowed to stand for 8 hours, then dried at 120°C for 4 hours, and finally calcined in a muffle furnace at 450°C for 4 hours. Before use, the catalyst needs to be reduced for 12 hours in a hydrogen atmosphere at 400°C.

[0059] Example 4

[0060] Mix 5.0g of magnesium oxide powder and 5.0g of aluminum oxide powder, then add 100.0g of deionized water and mix. Stir ultrasonically for 2 hours. Pour into a reflux condenser and boil continuously for 24 hours. After filtration, heat the product in a 500℃ furnace for 5 hours to completely remove moisture. Place the magnesium oxide powder in a CVD tube furnace and purge with Ar gas to maintain the absolute pressure in the furnace at 0.02MPa. After heating to 900℃ and stabilizing for 10 minutes, introduce methane at a flow rate of 20ml / min for 5 minutes, then stop the methane flow and immediately begin natural cooling. Graphene is grown on the surface of magnesium oxide. The resulting product is added dropwise with distilled water until it is initially wetted, and the volume of water consumed is recorded. Then, based on a Pd content (based on oxides) of 1% by weight of the total catalyst mass, a palladium nitrate impregnation solution is prepared. This solution is used to impregnate graphene@magnesium oxide@aluminum oxide until initially wetted, allowed to stand for 8 hours, then dried at 120°C for 4 hours, and finally calcined in a muffle furnace at 450°C for 4 hours. Before use, the catalyst needs to be reduced for 12 hours in a hydrogen atmosphere at 400°C.

[0061] Example 5

[0062] 10.0g of alumina powder was mixed with 100.0g of deionized water and stirred ultrasonically for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500℃ for 5 hours to completely remove moisture. Magnesium oxide powder was placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the furnace at 0.02MPa. After heating to 900℃ and stabilizing for 10 minutes, methane was introduced at a flow rate of 20ml / min for 5 minutes. The methane introduction was then stopped, and natural cooling was immediately initiated. Graphene is grown on the surface of alumina. The resulting product is added dropwise with distilled water until it is initially wetted, and the volume of water consumed is recorded. Then, based on a Pt content (calculated as oxide) of 3.0 wt% of the total catalyst mass, a tetraammineplatinum nitrate impregnation solution is prepared. Graphene@alumina is impregnated with this solution until initially wetted, allowed to stand for 8 hours, then dried at 120°C for 4 hours, and finally calcined in a muffle furnace at 450°C for 4 hours. The catalyst needs to be reduced for 12 hours in a hydrogen atmosphere at 400°C before use.

[0063] Example 6

[0064] 10.0 g of alumina powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. Magnesium oxide powder was placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the furnace at 0.02 MPa. After heating to 900°C and stabilizing for 10 minutes, methane was introduced at a flow rate of 30 ml / min for 2 minutes. The methane introduction was then stopped, and natural cooling was immediately initiated. Graphene is grown on the surface of alumina. The obtained product is added dropwise with distilled water until it is initially wetted, and the volume of water consumed is recorded. Then, based on a Ni content (based on oxides) of 25% by weight and a Mo content (based on oxides) of 1% by weight, a mixed impregnation solution of nickel nitrate and ammonium heptamolybdate is prepared. Graphene is impregnated with this solution until it is initially wetted, allowed to stand for 8 hours, dried at 120°C for 4 hours, and then calcined in a muffle furnace at 450°C for 4 hours to obtain the final product. Before use, the catalyst needs to be reduced at 400°C in a hydrogen atmosphere for 12 hours.

[0065] Example 7

[0066] 10.0 g of alumina powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. Distilled water was added dropwise to the obtained product until it was initially wetted, and the volume of water consumed was recorded. Based on a Ni content (based on oxides) of 25% by weight of the total catalyst mass and a Sn content (based on oxides) of 2% by weight of the total catalyst mass, a mixed impregnation solution of nickel nitrate and tin nitrate was prepared. The alumina was impregnated with this solution until initially wetted, allowed to stand for 8 hours, then dried at 120°C for 4 hours, and calcined in a muffle furnace at 450°C for 4 hours. The product was then reduced by heating at 400°C for 12 hours under a hydrogen atmosphere. Finally, the product was placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the tube furnace at 0.02 MPa. After heating to 900℃ and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. Then, the methane introduction was stopped and natural cooling was immediately initiated. Graphene then grew on the catalyst surface. Before use, the catalyst needed to be reduced at 400℃ in a hydrogen atmosphere for 12 hours.

[0067] Example 8

[0068] 10.0 g of alumina powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. Distilled water was added dropwise to the obtained product until it was initially wetted, and the volume of water consumed was recorded. Then, based on a Pd content (calculated as oxide) of 1% by weight of the total catalyst mass, a palladium nitrate impregnation solution was prepared. This solution was used to impregnate the alumina until it was initially wetted, allowed to stand for 8 hours, and then dried at 120°C for 4 hours. Afterward, it was calcined in a muffle furnace at 450°C for 4 hours and then removed. It was then reduced by heating at 400°C for 12 hours under a hydrogen atmosphere. The product was then placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the tube furnace at 0.02 MPa. After heating to 900℃ and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. Then, the methane introduction was stopped and natural cooling was immediately initiated. Graphene then grew on the catalyst surface. Before use, the catalyst needed to be reduced at 400℃ in a hydrogen atmosphere for 12 hours.

[0069] Example 9

[0070] Mix 5.0g of magnesium oxide powder and 5.0g of aluminum oxide powder, then add 100.0g of deionized water and mix. Stir ultrasonically for 2 hours. Pour into a reflux condenser and boil continuously for 24 hours. After filtration, heat the product in a 500℃ furnace for 5 hours to completely remove moisture. Add distilled water dropwise to the obtained product until it is initially wetted, and record the volume of water consumed. Then, based on a Ni content (based on oxides) of 25% by weight of the total catalyst mass, prepare a nickel nitrate impregnation solution. Impregnate magnesium oxide and aluminum oxide with this solution until initially wetted, let stand for 8 hours, then dry at 120℃ for 4 hours, and calcine at 450℃ for 4 hours in a muffle furnace. Remove and then reduce by heating at 400℃ for 12 hours in a hydrogen atmosphere. Finally, place the product in a CVD tube furnace, introduce Ar gas, and maintain the absolute pressure in the tube furnace at 0.02MPa. After heating to 900℃ and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. Then, the methane introduction was stopped and natural cooling was immediately initiated. Graphene then grew on the catalyst surface. Before use, the catalyst needed to be reduced at 400℃ in a hydrogen atmosphere for 12 hours.

[0071] Example 10

[0072] 10.0 g of magnesium oxide powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. Distilled water was added dropwise to the obtained product until it was initially wetted, and the volume of water consumed was recorded. A nickel nitrate impregnation solution was prepared based on a Ni content (based on oxides) of 25% by weight of the total catalyst mass. Magnesium oxide was impregnated with this solution until initially wetted, allowed to stand for 8 hours, and then dried at 120°C for 4 hours. After calcination at 450°C for 4 hours in a muffle furnace, the product was removed. It was then reduced by heating at 400°C for 12 hours under a hydrogen atmosphere. The product was then placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the tube furnace at 0.02 MPa. After heating to 900℃ and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. Then, the methane introduction was stopped and natural cooling was immediately initiated. Graphene then grew on the catalyst surface. Before use, the catalyst needed to be reduced at 400℃ in a hydrogen atmosphere for 12 hours.

[0073] Figure 3 TEM image of the alcohol liquid-phase reforming hydrogen production catalyst prepared in Example 10. From... Figure 3 It can be seen that the carrier loaded with nickel oxide active metal components serves as the core, and the carbon coating layer covers the core.

[0074] Example 11

[0075] 10.0 g of zirconium oxide powder was mixed with 100.0 g of deionized water and ultrasonically stirred for 2 hours. The mixture was then poured into a reflux condenser and boiled continuously for 24 hours. After filtration, the product was heated in a furnace at 500°C for 5 hours to completely remove moisture. Distilled water was added dropwise to the obtained product until it was initially wetted, and the volume of water consumed was recorded. A nickel nitrate impregnation solution was prepared based on a Ni content (based on oxides) of 25% by weight of the total catalyst mass. Magnesium oxide was impregnated with this solution until initially wetted, allowed to stand for 8 hours, and then dried at 120°C for 4 hours. After calcination at 450°C for 4 hours in a muffle furnace, the product was removed. It was then reduced by heating at 400°C for 12 hours under a hydrogen atmosphere. The product was then placed in a CVD tube furnace, and Ar gas was introduced to maintain the absolute pressure in the tube furnace at 0.02 MPa. After heating to 900℃ and stabilizing for 10 minutes, methane was introduced at a flow rate of 20 ml / min for 5 minutes. Then, the methane introduction was stopped and natural cooling was immediately initiated. Graphene then grew on the catalyst surface. Before use, the catalyst needed to be reduced at 400℃ in a hydrogen atmosphere for 12 hours.

[0076] Example 12

[0077] Mix 5.0g of titanium dioxide powder and 5.0g of zinc oxide powder, then add 100.0g of deionized water and mix. Stir ultrasonically for 2 hours. Pour into a reflux condenser and boil continuously for 24 hours. After filtration, heat the product in a 500℃ furnace for 5 hours to completely remove moisture. Place magnesium oxide powder in a CVD tube furnace and purge with Ar gas to maintain the absolute pressure in the furnace at 0.02MPa. After heating to 900℃ and stabilizing for 10 minutes, introduce methane at a flow rate of 2ml / min for 20 minutes, then stop the methane flow and immediately begin natural cooling. Graphene was grown on the surfaces of titanium oxide and zinc oxide. The resulting product was added dropwise with distilled water until initially wetted, and the volume of water consumed was recorded. Then, based on a Ni content (based on oxides) of 25% by weight of the total catalyst mass, a nickel nitrate impregnation solution was prepared. This solution was used to impregnate graphene@titanium oxide@zinc oxide until initially wetted, allowed to stand for 8 hours, then dried at 120°C for 4 hours, and finally calcined in a muffle furnace at 450°C for 4 hours. Before use, the catalyst needs to be reduced for 12 hours in a hydrogen atmosphere at 400°C.

[0078] Comparative Example 1

[0079] Add 10.0 g of industrial magnesium oxide support dropwise to distilled water until it is initially wetted, and record the volume of water consumed. Then, based on a Ni content (calculated as oxide) of 25% by weight of the total catalyst mass, prepare a nickel nitrate impregnation solution. Impregnate the magnesium oxide with this solution until it is initially wetted, let it stand for 8 hours, then dry it at 120°C for 4 hours, and calcine it in a muffle furnace at 450°C for 4 hours before removing it. Before use, the catalyst needs to be reduced at 400°C in a hydrogen atmosphere for 12 hours.

[0080] Comparative Example 2

[0081] Add 10.0g of industrial alumina support dropwise with distilled water until it is initially wetted, and record the volume of water consumed. Then, calculate based on the Pt content (calculated as oxide) being 3% by weight of the total catalyst mass to prepare a tetraammine nitrate platinum impregnation solution. Impregnate magnesium oxide with this solution until it is initially wetted, let it stand for 8 hours, then dry it at 120℃ for 4 hours, and calcine it in a muffle furnace at 450℃ for 4 hours before removing it. Before use, the catalyst needs to be reduced at 400℃ in a hydrogen atmosphere for 12 hours.

[0082] Examples 13-22, Comparative Example 4

[0083] Examples 13-22 used the catalysts obtained in Examples 1-10, and Comparative Example 4 used the catalyst obtained in Comparative Example 2, respectively, to carry out liquid-phase reforming reactions using Fischer-Tropsch synthesis wastewater as raw material. The organic matter content of the Fischer-Tropsch synthesis wastewater is shown in Table 1.

[0084] The obtained catalyst was loaded into the reactor. After catalyst reduction, nitrogen gas was introduced to the reaction pressure, and Fischer-Tropsch synthesis wastewater was introduced. The temperature was gradually increased to the reaction temperature to initiate the reaction. Specific reaction results are shown in Table 2. All data in Table 2 were measured after 48 hours of continuous reaction.

[0085] The reaction conditions for Examples 13-21 and Comparative Example 4 were: reaction pressure 3.5 MPa, reaction temperature 180 °C, and volume hourly space velocity 1.0 h⁻¹. -1 The gas-liquid ratio is 500 during feeding.

[0086] The reaction conditions for Example 22 were: reaction pressure 6.0 MPa, reaction temperature 260 °C, and volume hourly space velocity 5.0 h⁻¹. -1 The gas-liquid ratio during feeding is 350.

[0087] Examples 23-24, Comparative Example 3

[0088] Examples 23-24 used the catalysts obtained in Examples 11-12, and Comparative Example 3 used the catalyst obtained in Comparative Example 1. The alcohol-containing wastewater generated during the formation of methyl acetal was used as raw material. The main organic contents of the wastewater were diethylene glycol 0.05 wt%, methanol 1.2 wt%, formaldehyde 0.05 wt%, dimethoxymethane 0.002 wt%, polyethylene glycol 0.02 wt%, and formic acid 0.01 wt%.

[0089] The obtained catalyst was loaded into the reactor. After catalyst reduction, nitrogen gas was introduced to the reaction pressure, and alcohol-containing wastewater was introduced. The temperature was gradually increased to the reaction temperature to initiate the reaction. Specific reaction results are shown in Table 2. All data in Table 2 were measured after 48 hours of continuous reaction.

[0090] The reaction conditions for Example 23 and Comparative Example 3 were: reaction pressure 4.0 MPa, reaction temperature 210 °C, and volume hourly space velocity 10.0 h⁻¹. -1 The gas-liquid ratio during feeding is 210.

[0091] The reaction conditions for Example 24 were: reaction pressure 3.5 MPa, reaction temperature 230 °C, and volume hourly space velocity 8.0 h⁻¹. -1 The gas-liquid ratio during feeding is 300.

[0092] Table 1 Composition of Fischer-Tropsch synthesis wastewater

[0093]

[0094] Table 2 Reaction Results

[0095]

[0096]

[0097] The formulas for calculating liquid-phase carbon conversion and hydrogen selectivity in the table above are as follows:

[0098]

[0099]

[0100] a c Liquid phase carbon conversion rate

[0101] S H2 Hydrogen selectivity

[0102] n feed,c The total number of moles of carbon atoms in the raw material

[0103] n product,c The total number of moles of C atoms in the product gas

[0104] n product,H2 The number of moles of hydrogen in the product

[0105] x: The stoichiometric ratio of H2 to CO2 when alcohols react completely to produce CO2 and H2. The relevant reaction is:

[0106] C n H 2n+1 OH + (2n-1)H₂O → nCO₂ + 3nH₂

[0107] That is, x = 3n / n = 3

[0108] As can be seen from the data in Table 2, using the catalyst and method provided by this invention, the total carbon conversion rate in wastewater can reach up to 100%, and the hydrogen selectivity can reach up to 85%.

[0109] Example 25

[0110] Lifetime tests were conducted using the catalysts from Example 2, Comparative Example 1, and Comparative Example 2. The raw material was the Fischer-Tropsch synthesis wastewater shown in Table 1. The reaction conditions were: pressure 3.5 MPa, reaction temperature 220 °C, and volume hourly space velocity 5.0 h⁻¹. -1 The gas-liquid ratio was 350 at the time of feed, and a 2000-hour life test was conducted. Both the catalyst in Example 2 and the catalyst in Comparative Example 1 used magnesium oxide as the support and were loaded with Ni of the same metal content as the active center. The difference was that the magnesium oxide support of the catalyst in Example 2 was coated with a graphite carbon layer, while the catalyst in Comparative Example 1 had no carbon coating. Comparative Example 2 used alumina supported on Pt catalyst without a carbon coating.

[0111] Plot a graph with liquid-phase carbon conversion rate on the ordinate and time on the x-axis. Specific results are shown below. Figure 1 As shown.

[0112] from Figure 1 It can be seen that, using the catalyst of Example 2, the liquid-phase carbon conversion rate remained basically unchanged for 500 hours, then decreased slightly, with a very small decrease within 2000 hours. However, when using the catalysts of Comparative Example 1 and Comparative Example 2, the initial liquid-phase carbon conversion rates were lower than those of the catalyst of Example 2. The catalyst of Comparative Example 1 exhibited a poor conversion rate from the beginning and showed a significant downward trend within 2000 hours. The decrease in liquid-phase carbon conversion rate of the catalyst of Comparative Example 2 was slower, but its decrease was still greater than that of the catalyst of Example 2.

Claims

1. A method for producing hydrogen from alcohols via liquid-phase reforming, wherein alcohols are reformed to produce hydrogen in the presence of an alcohol-based liquid-phase reforming catalyst, wherein the alcohols are selected from one or more of C1-C10 monohydric alcohols and polyhydric alcohols; the alcohol-based liquid-phase reforming catalyst is a supported catalyst with a carbon coating layer, comprising a support, a carbon coating layer, an active metal component, and optional additives; the support is an inorganic oxide selected from one or more of magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, zirconium oxide, titanium oxide, zinc oxide, lanthanum oxide, cerium oxide, and alumina-silica; the active metal component is a Group VIII metal component; based on the catalyst as a whole, the mass fraction of carbon in the carbon coating layer is 0.01%-5%, and the mass fraction of the active metal component, calculated as oxides, is 0.01%-50%; the carbon coating layer is an oligolayer graphene layer having 1-20 graphene layers, wherein... The core is a carrier loaded with active metal components and optional additives, and the carbon coating layer covers the core. The alcohol-based liquid-phase reforming hydrogen production catalyst was obtained by the following preparation method: (1) Inorganic oxide powder and deionized water are mixed, with the mass ratio of deionized water to inorganic oxide powder being 5:1-30:

1. After ultrasonic stirring for 1-10 hours, the mixture is heated and kept boiling for 5-40 hours. The resulting mixture is filtered and dried, and then heated at 300-600℃ for 1-10 hours to obtain carrier powder. (2) The carrier powder obtained in step (1) is impregnated with a Group VIII active metal salt solution and an optional auxiliary salt solution, and then dried, calcined, and reduced to obtain a carrier powder loaded with active metal. The reduction is carried out under a hydrogen atmosphere for 4-24 hours at a temperature of 300-420°C. (3) Place the carrier powder loaded with active metal obtained in step (2) into a tube furnace, and introduce dilution gas into the furnace at a flow rate of 50 mL / min-10000 mL / min. The dilution gas is selected from one or more of Ar, He, and N2. Heat the furnace to 700-1000℃, and introduce methane at a flow rate of 1 mL / min-100 mL / min for 0.5 min-30 min. Stop introducing methane and maintain the flow rate of dilution gas at 50 mL / min-100000 mL / min until the temperature drops to room temperature. The absolute pressure in the tube furnace is 0.005 kPa-20 kPa to obtain an alcohol liquid phase reforming hydrogen production catalyst. The method for producing hydrogen by liquid-phase reforming of alcohols is applied to the treatment of Fischer-Tropsch synthesis wastewater. The Fischer-Tropsch synthesis wastewater originates from water produced by the Fischer-Tropsch synthesis reaction. The Fischer-Tropsch synthesis wastewater contains C1-C10 alcohols, acids, aldehydes, and ketones, and the total mass fraction of oxygenated organic matter in the Fischer-Tropsch synthesis wastewater is 0.5%~30%.

2. The method according to claim 1, characterized in that, The inorganic oxide powder is selected from one or more of magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, zirconium oxide, titanium oxide, zinc oxide, lanthanum oxide, cerium oxide, and aluminum oxide-silicon oxide powder; the average particle size of the inorganic oxide powder is 0.1 μm-100 μm.

3. The method according to claim 2, characterized in that, The average particle size of the inorganic oxide powder is 1μm-50μm.

4. The method according to claim 1, characterized in that, The additives are selected from one or more combinations of elements of Group IIIA, IVA, VA, IB, IIB, IIB, IIIB, IVB, VB, VIB, VIIB or their oxides, lanthanide metals or their metal oxides, and actinide metals or their metal oxides.

5. The method according to claim 1, characterized in that, The polyol is selected from one or more of ethylene glycol, glycerol, sorbitol, and glucose.

6. The method according to claim 1, characterized in that, The reaction conditions for hydrogen production from alcohols via liquid-phase reforming are: reaction temperature of 180℃-280℃, pressure of 1.1MPa-7.0MPa, and volume hourly space velocity of 0.1-15 h⁻¹. -1 The buffer gas is nitrogen, and the gas-liquid volume ratio during feeding is 0-800.

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