A coated catalyst, its preparation method, and its application in biomass gasification coupled with green hydrogen to methanol

Abstract

The present application discloses a coated catalyst, a preparation method thereof, and an application in biomass gasification coupled with green hydrogen to methanol. The inner layer carrier of the coated catalyst is CuZnZrAl, and the coating component is mesoporous SiO2. The coated mesoporous silica coating catalyst CuZnZrAl@SiO2 is prepared by a surface deposition method. The mesoporous silica coating layer serves as a physical isolation layer, and its coating layer can protect fine particles and well-dispersed CuZnZrAl from sintering problems during roasting and high-temperature reactions, and the ability to operate stably for a long time at high temperatures is significantly improved. The coated CuZnZrAl@SiO2 catalyst can achieve efficient conversion of CO / CO2 / H2 into methanol, has high stability, and is simple to prepare, and is suitable for application in large-scale biomass gasification coupled with green hydrogen to methanol.

Description

Technical Field

[0001] The present application relates to a coated catalyst, a preparation method thereof, and application in the production of methanol by coupling biomass gasification with green hydrogen, belonging to the technical field of synthetic methanol catalysts. Background Art

[0002] In recent years, the use of clean, green fuels has received significant attention in the marine industry. Clean energy sources such as LNG, batteries, methanol, hydrogen, and ammonia have been used to varying degrees on ships both domestically and internationally. Methanol is currently the most advantageous carbon-neutral liquid fuel at room temperature and pressure. The methanol-from-CO2 route, driven by hydrogen production from biomass and renewable energy, is considered an effective technological path for the synthesis of carbon-neutral fuels in the future.

[0003] Traditional biomass methanol production generally uses biomass gasification technology, which gasifies biomass into a mixture composed primarily of CO, H₂, and CO₂. After conversion and purification processes such as low-temperature methanol washing, synthesis gas consisting primarily of CO and H₂ is obtained. The low-temperature methanol washing process releases excess CO₂, and methanol synthesis is then carried out. This indicates that traditional biomass methanol production also emits large amounts of CO₂, significantly wasting the carbon resources of biomass. Subsequently, some scholars have proposed the idea of ​​combining biomass gasification with renewable energy hydrogen production to synthesize methanol. This eliminates the conversion reaction and introduces renewable energy to produce green hydrogen. The new mixture composition satisfies the requirements of both the CO + 2H₂ → CH₃OH and CO₂ + 3H₂ → CH₃OH + H₂O reactions, achieving complete conversion of the carbon elements of biomass gasification into methanol and achieving zero-carbon biomass methanol production.

[0004] Currently, the most studied catalysts for methanol synthesis are Cu-based catalysts derived from syngas to methanol. However, Cu-based catalysts have poor heat resistance and can sinter during high-temperature reactions. Furthermore, the water generated during the CO / CO2 co-hydrogenation reaction to synthesize methanol accelerates the sintering of Cu-based catalysts. Therefore, the design and development of catalysts with enhanced high-temperature reaction stability holds great promise. Summary of the Invention

[0005] The present application provides a coated CuZnZrAl@SiO2 catalyst for the co-hydrogenation of CO / CO2 to synthesize methanol. The catalyst comprises an active component, a carrier of CuZnZrAl, and a coating component of SiO2. The coated mesoporous silica coating catalyst CuZnZrAl@SiO2 is prepared by a surface deposition method and has good stability. The formation of a microemulsion between the surfactant and the carrier is the key to the preparation of the mesoporous SiO2 coating layer. The mesoporous SiO2 coating layer can protect the fine particles and well-dispersed CuZnZrAl from sintering problems during roasting and high-temperature reactions, and the ability to operate stably for a long time at high temperatures is significantly improved. In addition, compared with CuZnZrAl as a catalyst, the coated CuZnZrAl@SiO2 catalyst exhibits better stability and is suitable for application in large-scale biomass gasification coupled with green hydrogen to methanol.

[0006] According to one aspect of the present application, a coated catalyst is provided, comprising a coating component and an inner layer carrier;

[0007] The coating component is mesoporous SiO2;

[0008] The inner layer carrier includes active components, and the active components include oxides of copper, zinc, zirconium and aluminum elements;

[0009] In the inner layer carrier, the molar content of copper oxide is 30-70%, the molar content of zinc oxide is 10-45%, the molar content of zirconium oxide is 1-20%, and the molar content of aluminum oxide is 1-20%.

[0010] Optionally, in the inner layer carrier, the molar content of copper oxide is independently selected from any value of 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70% or a range between any two of the above.

[0011] Optionally, in the inner layer carrier, the molar content of zinc oxide is independently selected from any value among 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or a range between any two of the above.

[0012] Optionally, in the inner layer carrier, the molar content of zirconium oxide is independently selected from any value among 1%, 5%, 10%, 15%, 20% or a range between any two of the above.

[0013] Optionally, in the inner layer carrier, the molar content of aluminum oxide is independently selected from any value among 1%, 5%, 10%, 15%, 20% or a range between any two of the above.

[0014] Optionally, in the inner layer carrier, the molar content of copper oxide is 45-65%, the molar content of zinc oxide is 25-30%, the molar content of zirconium oxide is 5-10%, and the molar content of aluminum oxide is 5-10%.

[0015] Optionally, the molar amount of the coating component is 0.1% to 20% of the molar amount of the inner layer carrier, the molar amount of the coating component is calculated based on the molar content of SiO2, and the molar amount of the inner layer carrier is calculated based on the molar content of the inner layer carrier.

[0016] Optionally, the molar amount of the coating component is independently selected from any value among 0.1%, 0.5%, 1%, 3%, 4%, 5%, 7%, 10%, 12%, 15%, 20% of the molar amount of the inner layer carrier, or a range value between any two of the above.

[0017] Optionally, the molar amount of the coating component is 0.5% to 10% of the molar amount of the inner layer carrier, the molar amount of the coating component is calculated based on the molar content of SiO2, and the molar amount of the inner layer carrier is calculated based on the molar content of the inner layer carrier.

[0018] According to another aspect of the present application, a method for preparing the above-mentioned coated catalyst is provided, the preparation method comprising the following steps:

[0019] (1) reacting a mixture I containing a copper source, a zinc source, a zirconium source, an aluminum source, and a precipitant at a certain temperature I, aging I, filtering I, drying I, and calcining I to obtain the inner layer carrier;

[0020] (2) Adding an organosilicon solution dropwise to a mixture II containing an inner layer carrier and a surfactant, reacting II at a certain temperature, and then aging II, filtering, drying II, and calcining II to obtain the coated catalyst.

[0021] Optionally, the preparation method comprises the following steps:

[0022] (1) obtaining a CuZnZrAl carrier by using a coprecipitation method, mixing a mixed metal salt solution of copper, zinc, zirconium, and aluminum with a precipitant solution I, causing a precipitation reaction under a certain temperature and pressure, and then aging I, filtering I, drying I, and calcining I to obtain the CuZnZrAl carrier;

[0023] (2) crushing the CuZnZrAl support obtained in (1) and mixing it with water to obtain a suspension;

[0024] Then, a surfactant is added to the suspension and stirred, and finally an organosilicon ethanol solution is added dropwise to cause a hydrolysis reaction; after aging II, filtering, drying II, and calcining II, the coated catalyst is obtained.

[0025] Optionally, in step (2), the surfactant is selected from at least one of Triton X-100 and polyvinyl pyrrolidone.

[0026] Optionally, the organosilicon in the organosilicon solution is selected from at least one of ethyl orthosilicate and methyldiethoxysilane.

[0027] Optionally, the solvent in the organosilicon solution is ethanol.

[0028] Optionally, the content of Si element in the organic silicon solution is 0.1 mol / L to 1 mol / L.

[0029] Optionally, the content of Si element in the organic silicon solution is independently selected from any value among 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 1 mol / L or a range between any two of the above.

[0030] Optionally, the molar ratio of the organosilicon solution to the inner layer carrier is 1:1 to 1:100.

[0031] Optionally, the molar ratio of the organosilicon solution to the inner layer carrier is independently selected from any value of 1:1, 1:5, 1:10, 1:20, 1:30, 1:50, 1:80, 1:100, or a range between any two of the above values.

[0032] Optionally, the molar ratio of the surfactant to the inner layer carrier is 1:50 to 1:200.

[0033] Optionally, the amount ratio of the surfactant to the inner layer carrier is independently selected from any value among 1:50, 1:60, 1:80, 1:100, 1:130, 1:150, 1:180, 1:200 or a range between any two of the above.

[0034] Optionally, in step (1), the precipitant is selected from at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide.

[0035] Optionally, the concentration of the precipitant is 0.3 to 1.5 mol / L.

[0036] Optionally, the concentration of the precipitant is independently selected from any value among 0.3 mol / L, 0.5 mol / L, 0.7 mol / L, 0.9 mol / L, 1.0 mol / L, 1.2 mol / L, 1.5 mol / L or a range of any two of the above values.

[0037] Optionally, in step (1), the pH of the mixture I is 5-9.

[0038] Optionally, in step (1), the pH of the mixture I is independently selected from any value among 5, 6, 7, 8, 9 or a range between any two of the above values.

[0039] Optionally, the concentration of the precipitant is 0.5-1.0 mol / L.

[0040] Optionally, the molar ratio of the metal salt to the precipitant is 1:1-2, and the metal salt includes a copper source, a zinc source, a zirconium source and an aluminum source.

[0041] Optionally, the copper source is selected from copper nitrate and / or copper acetate.

[0042] Optionally, the zinc source is selected from zinc nitrate and / or zinc acetate.

[0043] Optionally, the zirconium source is selected from zirconium nitrate and / or zirconyl nitrate.

[0044] Optionally, the aluminum source is selected from aluminum nitrate and / or aluminum acetate.

[0045] Optionally, in step (1), the temperature of the aging I is 20 to 80° C., and the time of the aging I is 2 to 8 hours.

[0046] Optionally, the temperature of the aging I is independently selected from any value among 20°C, 40°C, 60°C, 80°C or a range between any two of the above values.

[0047] Optionally, the aging time I is independently selected from any value among 2h, 4h, 6h, 8h or a range between any two of the above.

[0048] Optionally, the temperature of the drying I is 60 to 120° C., and the time of the drying I is 6 to 24 hours.

[0049] Optionally, the drying temperature I is independently selected from any value among 60°C, 80°C, 100°C, 120°C or a range between any two of the above values.

[0050] Optionally, the drying time I is independently selected from any value among 6h, 8h, 12h, 16h, 20h, 24h or a range value between any two of the above.

[0051] Optionally, the temperature of the calcination I is 300-450° C., and the time of the calcination I is 3-24 hours.

[0052] Optionally, the calcination temperature I is independently selected from any value among 300°C, 320°C, 350°C, 400°C, 420°C, 450°C, or a range between any two of the above values.

[0053] Optionally, the calcination time I is independently selected from any value among 3h, 5h, 8h, 12h, 16h, 20h, 24h or a range value between any two of the above.

[0054] Optionally, in step (2), the temperature of the aging II is 20 to 60° C., and the time of the aging II is 3 to 10 hours.

[0055] Optionally, the temperature of the aging II is independently selected from any value among 20°C, 30°C, 40°C, 50°C, 60°C or a range between any two of the above values.

[0056] Optionally, the aging II time is independently selected from any value among 3h, 5h, 7h, 9h, 10h or a range between any two of the above values.

[0057] Optionally, the temperature of the drying II is 80 to 120° C., and the time of the drying II is 12 to 24 hours.

[0058] Optionally, the temperature of the drying II is independently selected from any value among 80°C, 90°C, 100°C, 110°C, 120°C or a range between any two of the above values.

[0059] Optionally, the drying time II is independently selected from any value among 12h, 16h, 20h, 24h or a range between any two of the above.

[0060] Optionally, the temperature of the calcination II is 300 to 450° C., and the time of the calcination II is 3 to 24 hours.

[0061] Optionally, the temperature of the calcination II is independently selected from any value among 300°C, 320°C, 350°C, 400°C, 420°C, 450°C, or a range between any two of the above values.

[0062] Optionally, the calcination time II is independently selected from any value among 3h, 5h, 8h, 12h, 16h, 20h, 24h, or a range between any two of the above.

[0063] According to another aspect of the present application, there is provided a use of the above-mentioned coated catalyst in biomass gasification coupled with green hydrogen to methanol production, wherein the method of biomass gasification coupled with green hydrogen to methanol production comprises:

[0064] The biomass gasification effective gas and hydrogen I are mixed and reacted with the coated catalyst to obtain a product containing methanol;

[0065] The biomass gasification effective gas includes CO, CO2 and H2.

[0066] Optionally, the method comprises: loading a catalyst into a fixed bed reactor, introducing effective gas from biomass gasification and H2 obtained from hydrogen production from renewable energy, contacting the catalyst to cause a catalytic reaction, and obtaining a product containing methanol.

[0067] Optionally, before the coated catalyst is contacted with the reaction, the coated catalyst needs to be activated.

[0068] Optionally, the activated atmosphere is a mixed gas containing hydrogen II and an inactive atmosphere.

[0069] Optionally, the inert atmosphere is selected from at least one of helium, argon, and nitrogen.

[0070] Optionally, in the mixed gas, the volume concentration of the hydrogen II is 2 to 99.999%.

[0071] Optionally, in the mixed gas, the volume concentration of the hydrogen II is independently selected from any value among 2%, 5%, 10%, 20%, 50%, 80%, 99.999% or a range between any two of the above.

[0072] Optionally, in the mixed gas, the volume concentration of the hydrogen II is 5-10%.

[0073] Optionally, the activation temperature is 200-400° C., and the activation time is 2-24 hours.

[0074] Optionally, the activation temperature is independently selected from any value among 200°C, 250°C, 300°C, 350°C, 400°C or a range between any two of the above values.

[0075] Optionally, the activation time is independently selected from any value among 2h, 6h, 10h, 14h, 18h, 20h, 24h or a range between any two of the above.

[0076] Optionally, the activation pressure is 0.1-1 MPa.

[0077] Optionally, the activation pressure is independently selected from any value among 0.1 MPa, 0.4 MPa, 0.6 MPa, 0.8 MPa, 1 MPa, or a range between any two of the above values.

[0078] Optionally, the hydrogen I is obtained by producing hydrogen from renewable energy.

[0079] Optionally, the gas pressure of the raw material is 2 to 10 MPa.

[0080] Optionally, the gas pressure of the raw material is independently selected from any value among 2MPa, 4MPa, 6MPa, 8MPa, 10MPa or a range between any two of the above values.

[0081] Optionally, the reaction temperature is 160-280°C.

[0082] Optionally, the reaction temperature is independently selected from any value among 160°C, 180°C, 200°C, 220°C, 250°C, 280°C or a range between any two of the above values.

[0083] Optionally, the feed space velocity of the raw material is 4000~24000h -1 .

[0084] Optionally, the feed space velocity of the raw material is independently selected from 4000h -1 , 8000h -1 、12000h -1 , 16000h -1 、20000h -1 , 24000h -1 Any value in or a range of values ​​between any two of the above.

[0085] The active component and carrier of the coated catalyst disclosed in the present application are CuZnZrAl, the coating component is SiO2, and the coated mesoporous silica coating catalyst CuZnZrAl@SiO2 is prepared by surface deposition method. The mesoporous silica coating layer serves as a physical isolation layer, and its coating layer can protect the fine particles and well-dispersed CuZnZrAl from sintering problems during roasting and high-temperature reactions, and the ability to operate stably for a long time at high temperatures is significantly improved. The coated CuZnZrAl@SiO2 catalyst can realize the efficient conversion of CO / CO2 / H2 into methanol, has high stability, and is simple to prepare, and is suitable for application in large-scale biomass gasification coupled with green hydrogen to methanol.

[0086] The beneficial effects of this application include:

[0087] This application discloses a coated methanol synthesis catalyst for use in biomass gasification coupled with renewable energy to produce green hydrogen and methanol. The coated mesoporous silica-coated catalyst, CuZnZrAl@SiO2, is prepared by a surface deposition method. The SiO2 coating protects the fine particles and well-dispersed CuZnZrAl from sintering during calcination and high-temperature reactions, significantly improving its ability to operate stably at high temperatures for a long time. Under conditions of 5MPa, 220°C, and 8000mL / (g·h), the coated catalyst only decayed by 2.7% after 300h of operation, while CuZnZrAl decayed by 7.0% under the same conditions. The coated CuZnZrAl@SiO2 catalyst exhibits superior stability and is suitable for industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0088] Figure 1 These are the XRD patterns of the coated catalysts and comparative examples prepared in Comparative Example 1 and Examples 1 to 5 of the present application.

[0089] Figure 2 This is a diagram showing the stability evaluation results of the catalysts obtained in Example 3 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0090] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0091] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0092] In the present application, the effective gas after purification after biomass gasification is CO, CO2, and H2. The composition of biomass gasification has a CO molar content of 40-45%, a CO2 molar content of 20-30%, and an H2 molar content of 33-45%. The reaction gas mixed with hydrogen produced by coupling water electrolysis has a mixed gas composition that meets the requirements of the two reactions CO+2H2→CH3OH and CO2+3H2→CH3OH+H2O. Then, the new mixed gas has a CO molar content of 15-21%, a CO2 molar content of 9-18%, and an H2 molar content of 67-72%.

[0093] The mixed feed gas is pressurized and introduced into a fixed-bed reactor. The reaction activity is evaluated on a fixed-bed reactor-GC system. Reaction conditions are: 2-10 MPa, 160-280°C, and a space velocity (GHSV) of 4000-24000 mL / (hg). Prior to the reaction, the oxide catalyst is activated at atmospheric pressure with pure hydrogen or a mixture of hydrogen and an inert gas at 200-450°C for 2-24 hours. The temperature is then adjusted to the desired reaction temperature, and the feed gas is switched in. The tail gas from the reactor outlet is discharged to atmospheric pressure via a backpressure valve and sampled at 150°C through a ten-port gas chromatograph valve. The sample is then analyzed online using a thermal conductivity detector (TCD) and a hydrogen flame detector (FID) on an Agilent GC-8890 gas chromatograph. The former chromatographic column is a 5A molecular sieve combined with Propark Q (Agilent), with a column length of 3m, using H2 as the carrier gas, working at 90°C, and is used for the separation and detection of CO2, Ar, and CO; the latter chromatographic column is a TG-BOND Q capillary column (Thermo Fisher Scientific), with specifications of 30m×0.32mm×10μm, using N2 as the carrier gas, and is used for the separation and detection of low-carbon hydrocarbons and alcohols.

[0094] The decay rate refers to the degree of catalyst activity decay within a certain period of time during catalyst evaluation. It is calculated using the initial and final methanol space-time yields of the reaction using the formula: (1-final methanol space-time yield / initial methanol space-time yield)*100%.

[0095] Comparative Example 1

[0096] Weigh 180mmol Cu(NO3)2·3H2O, 60mmol Zn(NO3)2·6H2O, 30mmol Zr(NO3)4·5H2O, and 30mmol Al(NO3)2·9H2O to prepare 300mL of salt solution; then weigh 360mmol Na2CO3 to prepare 360mL of Na2CO3 aqueous solution; then, add the metal salt solution and Na2CO3 aqueous solution dropwise into a 1000mL four-necked beaker with a stirring speed of 600r / min to cause precipitation reaction, and age at 70°C; insert a pH meter and thermometer to control pH=7.0; age for 4h; after aging, filter and wash with deionized water until there is no sodium ion in the filtrate; dry the filter cake at 110°C and calcine in air at 350°C for 4h to obtain about 25g of catalyst CuZnZrAl.

[0097] 3 g of the resulting catalyst was weighed, pelletized, crushed, and screened, with 40-80 mesh sizes selected for evaluation. 1.0 g of the screened catalyst was loaded into a 6 mm inner diameter reaction tube and reduced at 250°C for 3 h in pure H₂ at atmospheric pressure at a flow rate of 20 mL / min. A mixed feed gas of n(H₂):n(CO):n(CO₂) = 69.8:20.9:9.3 was then introduced. The reaction was carried out at 5 MPa, 220°C, and GHSV = 8000 mL / (hg). Detailed results are shown in Table 1.

[0098] Example 1

[0099] The catalyst CuZnZrAl prepared in Comparative Example 1 was crushed to 200-300 mesh; in the first step, 4 g of CuZnZrAl powder was weighed as a carrier, added to a 250 mL beaker, 100 mL of deionized water was added, and stirred for 30 minutes to obtain a carrier turbid liquid; in the second step, 0.2 g of Triton X-100 was added and stirred for another 30 minutes to allow the surfactant to fully contact the carrier particles; in the third step, 2.5 mL of 0.3 mol / L ethyl orthosilicate ethanol solution was measured and slowly added dropwise to the carrier suspension to cause a hydrolysis reaction; the mixture was stirred at 60°C and 800 r / min for 6 hours and then cooled; the mixture was filtered and washed with ethanol and deionized water respectively; the filter cake was dried at 80°C for 20 hours, and the dried sample was calcined in an air atmosphere at 350°C for 4 hours to obtain a coated catalyst CuZnZrAl@SiO2-1.

[0100] The evaluation steps are the same as those of Comparative Example 1. Detailed results are shown in Table 1.

[0101] Example 2

[0102] The catalyst CuZnZrAl prepared in Comparative Example 1 was crushed to 200-300 mesh; in the first step, 4 g of CuZnZrAl powder was weighed as a carrier, added to a 250 mL beaker, 100 mL of deionized water was added, and stirred for 30 minutes to obtain a carrier turbid liquid; in the second step, 0.2 g of Triton X-100 was added and stirred for another 30 minutes to allow the surfactant to fully contact the carrier particles; in the third step, 5.0 mL of 0.3 mol / L ethyl orthosilicate ethanol solution was measured and slowly added dropwise to the carrier suspension to cause a hydrolysis reaction; after stirring at 60°C and 800 r / min for 6 hours, it was cooled; filtered and washed with ethanol and deionized water respectively; the obtained filter cake was dried at 80°C for 20 hours, and the dried sample was calcined in an air atmosphere at 350°C for 4 hours to obtain a coated catalyst CuZnZrAl@SiO2-2.

[0103] The evaluation steps are the same as those of Comparative Example 1. Detailed results are shown in Table 1.

[0104] Example 3

[0105] The catalyst CuZnZrAl prepared in Comparative Example 1 was crushed to 200-300 mesh; in the first step, 4 g of CuZnZrAl powder was weighed as a carrier, added to a 250 mL beaker, 100 mL of deionized water was added, and stirred for 30 minutes to obtain a carrier turbid liquid; in the second step, 0.2 g of Triton X-100 was added and stirred for another 30 minutes to allow the surfactant to fully contact the carrier particles; in the third step, 10.0 mL of 0.3 mol / L ethyl orthosilicate ethanol solution was measured and slowly added dropwise to the carrier suspension to cause a hydrolysis reaction; after stirring at 60°C and 800 r / min for 6 hours, it was cooled; filtered and washed with ethanol and deionized water respectively; the obtained filter cake was dried at 80°C for 20 hours, and the dried sample was calcined in an air atmosphere at 350°C for 4 hours to obtain a coated catalyst CuZnZrAl@SiO2-3.

[0106] The evaluation steps are the same as those of Comparative Example 1. Detailed results are shown in Table 1.

[0107] Example 4

[0108] The catalyst CuZnZrAl prepared in Comparative Example 1 was crushed to 200-300 mesh; in the first step, 4 g of CuZnZrAl powder was weighed as a carrier, added to a 250 mL beaker, 100 mL of deionized water was added, and stirred for 30 minutes to obtain a carrier turbid liquid; in the second step, 0.2 g of Triton X-100 was added and stirred for another 30 minutes to allow the surfactant to fully contact the carrier particles; in the third step, 15.0 mL of 0.3 mol / L ethyl orthosilicate ethanol solution was measured and slowly added dropwise to the carrier suspension to cause a hydrolysis reaction; after stirring at 60°C and 800 r / min for 6 hours, it was cooled; filtered and washed with ethanol and deionized water respectively; the obtained filter cake was dried at 80°C for 20 hours, and the dried sample was calcined in an air atmosphere at 350°C for 4 hours to obtain a coated catalyst CuZnZrAl@SiO2-4.

[0109] The evaluation steps are the same as those of Comparative Example 1. Detailed results are shown in Table 1.

[0110] Example 5

[0111] The catalyst CuZnZrAl prepared in Comparative Example 1 was crushed to 200-300 mesh; in the first step, 4 g of CuZnZrAl powder was weighed as a carrier, added to a 250 mL beaker, 100 mL of deionized water was added, and stirred for 30 minutes to obtain a carrier turbid liquid; in the second step, 0.2 g of Triton X-100 was added and stirred for another 30 minutes to allow the surfactant to fully contact the carrier particles; in the third step, 20.0 mL of 0.3 mol / L ethyl orthosilicate ethanol solution was measured and slowly added dropwise to the carrier suspension to cause a hydrolysis reaction; after stirring at 60°C and 800 r / min for 6 hours, the mixture was cooled; filtered and washed with ethanol and deionized water respectively; the filter cake was dried at 80°C for 20 hours, and the dried sample was calcined in an air atmosphere at 350°C for 4 hours to obtain a coated catalyst CuZnZrAl@SiO2-5.

[0112] like Figure 1 As shown, from Figure 1 It can be seen that CuZnZrAl coated with silicon oxide has characteristic peaks of amorphous copper oxide and zinc oxide, while the characteristic peaks of zirconium oxide and aluminum oxide are not obvious, and the characteristic peaks of the silicon oxide content are not obvious either.

[0113] The evaluation steps are the same as those of Comparative Example 1. Detailed results are shown in Table 1.

[0114] Table 1 Catalytic performance evaluation results of the examples

[0115]

[0116] From the performance evaluation results in Appendix 1, it can be seen that the activity of the CuZnZrAl catalyst coated with a certain amount of SiO2 layer has decreased, but under the conditions of 5MPa, 220℃, and 8000mL / (g·h), the catalytic activity of the coated catalyst has only decreased by 2.7% after running for 300h, while the catalytic activity of CuZnZrAl under the same conditions has decreased by 7.0%. The coated CuZnZrAl@SiO2 catalyst shows better stability. Figure 2 It can also be seen that the decay of CuZnZrAl@SiO2 weakens with the reaction time and tends to be flat.

[0117] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. Application of a coated catalyst in biomass gasification coupled with green hydrogen to methanol, characterized in that: The following steps are involved: The biomass gasification effective gas and hydrogen I are mixed and reacted with the coated catalyst to obtain a product containing methanol; The biomass gasification effective gas includes CO, CO2 and H2; The coated catalyst comprises a coating component and an inner layer carrier; The coating component is mesoporous SiO2; The inner layer carrier is CuZnZrAl, an oxide of copper, zinc, zirconium and aluminum; In the inner layer carrier, the molar content of copper oxide is 30-70%, the molar content of zinc oxide is 10-45%, the molar content of zirconium oxide is 1-20%, and the molar content of aluminum oxide is 1-20%; The preparation method of the coated catalyst comprises the following steps: (1) obtaining a CuZnZrAl carrier by using a co-precipitation method, mixing a mixed metal salt solution of copper, zinc, zirconium, and aluminum with a precipitant solution, causing a precipitation reaction under a certain temperature and pressure, and then aging I, filtering, drying I, and roasting I to obtain the CuZnZrAl carrier; (2) The CuZnZrAl support obtained in (1) is crushed and mixed with deionized water to obtain a suspension; a surfactant is then added to the suspension and stirred, and finally an organosilicon ethanol solution is added dropwise to cause a hydrolysis reaction; after aging II, filtering, drying II, and calcining II, the coated catalyst is obtained; In the step (2), the surfactant is selected from at least one of Triton X-100 and polyvinyl pyrrolidone; The organosilicon in the organosilicon ethanol solution is selected from at least one of ethyl orthosilicate and methyldiethoxysilane; The molar amount of the coating component is 0.1% to 20% of the molar amount of the inner layer carrier, the molar amount of the coating component is calculated based on the molar content of SiO2, and the molar amount of the inner layer carrier is calculated based on the molar content of the inner layer carrier.

2. The use according to claim 1, characterized in that The content of Si element in the organosilicon ethanol solution is 0.1 mol / L~1 mol / L; The molar ratio of the organosilicon ethanol solution to the inner layer carrier is 1:1 to 1:100; The molar ratio of the surfactant to the inner layer carrier is 1:50 to 1:

200.

3. The use according to claim 1, characterized in that In the step (1), the precipitant is selected from at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, and potassium hydroxide; The concentration of the precipitant is 0.3-1.5 mol / L; The molar ratio of the metal salt to the precipitant is 1:1-2, and the metal salt includes a copper source, a zinc source, a zirconium source and an aluminum source; The copper source is selected from copper nitrate and / or copper acetate; The zinc source is selected from zinc nitrate and / or zinc acetate; The zirconium source is selected from zirconium nitrate and / or zirconyl nitrate; The aluminum source is selected from aluminum nitrate and / or aluminum acetate.

4. The use according to claim 1, characterized in that In the step (1), the temperature of the aging I is 20-80°C, and the time of the aging I is 2-8 hours; The drying temperature is 60-120° C. and the drying time is 6-24 hours. The temperature of the roasting I is 300-450° C., and the time of the roasting I is 3-24 hours; In the step (2), the temperature of the aging II is 20-60°C, and the time of the aging II is 3-10 hours; The temperature of the drying II is 80-120° C., and the time of the drying II is 12-24 hours; The temperature of the calcination II is 300-450° C., and the time of the calcination II is 3-24 hours.

5. The use according to claim 1, characterized in that Before the coated catalyst is contacted with the reaction, the coated catalyst needs to be activated; The activated atmosphere is a mixed gas containing hydrogen II and an inactive atmosphere; The inert atmosphere is selected from at least one of helium, argon, and nitrogen; In the mixed gas, the volume concentration of the hydrogen II is 2 to 99.999%; The activation temperature is 200-400°C, and the activation time is 2-24 hours; The activation pressure is 0.1~1MPa; The hydrogen I is obtained by producing hydrogen through renewable energy.

6. The use according to claim 5, characterized in that In the mixed gas, the volume concentration of the hydrogen II is 5-10%.

7. The use according to claim 1, characterized in that The gas pressure of the raw material is 2~10MPa; The reaction temperature is 160-280°C; The feed space velocity of the raw materials is 4000~24000 h -1 .

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