A 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material, its preparation method and application

Abstract

The present invention discloses a 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material, its preparation method and application. The catalyst uses improved ceramic clay and waste vanadium-titanium denitration catalyst as carriers, and nickel tungstate micro wires modified by plasma surface as catalytic active components. The improvement method of ceramic clay is that the ceramic clay undergoes a hydrothermal activation process to improve the water retention performance. The catalyst can not only realize the harmless treatment of waste vanadium-titanium denitration catalyst, but also recycle it. Moreover, the catalyst has a low applicable temperature and a high conversion efficiency. By using plasma-enhanced catalysis, methanol can be reformed into H2 and CO2 at room temperature, and both the methanol conversion efficiency and the H2 selectivity are higher than 90%. The preparation process is simple, and it has broad market application prospects.

Description

Technical Field

[0001] The present invention provides a 3D printed reforming hydrogen production catalyst using waste vanadium titanium denitration catalyst as raw material, and a preparation method and application thereof, belonging to the field of resource utilization of waste denitration catalysts and environmentally friendly catalytic materials. Background Art

[0002] Nitrogen oxides are the main cause of pollution such as haze and acid rain. Industrial flue gas denitrification such as thermal power plants has become the focus of current air pollution control. As of 2017, there are more than 1.2 million cubic meters of catalysts in service. According to the centralized launch of thermal power denitrification projects in 2013, the average life of catalysts is 3-5 years, and vanadium titanium denitrification catalysts will soon be included in the batch "replacement period". On the other hand, the website of the Ministry of Environmental Protection issued the "Notice on Strengthening the Supervision of Waste Flue Gas Denitrification Catalysts", which included the management, regeneration and utilization of waste flue gas denitrification catalysts into hazardous waste management and required the improvement of their regeneration and utilization and disposal capabilities. Therefore, the regeneration or resource utilization of waste vanadium titanium denitrification catalysts has become an environmental problem that needs to be solved urgently. The regeneration rate of thermal power denitrification catalysts is about 60%, and conventional catalysts can usually be regenerated 2-3 times, and then they can only be completely scrapped. That is, catalyst regeneration is not actually the final treatment method. On this basis, the high-value-added resource utilization of waste vanadium titanium denitrification catalysts is a feasible and economical conversion method.

[0003] Among the existing patents for processing waste vanadium-titanium denitration catalysts, patent CN201410623778.8 designs a continuous device to recover vanadium, titanium and molybdenum elements from waste vanadium-titanium denitration catalysts. Patent CN201510265236.2 obtains titanium-rich leaching residue and tungsten-molybdenum-vanadium-containing leaching solution after leaching the waste vanadium-titanium denitration catalyst, and adjusts the proportion of the content of each substance after synchronous purification of the valuable components in the leaching solution to prepare a mixture of catalytic components, and further prepares a new catalyst. Patent 201710717702.5 uses nitric acid solution to clean the surface of the waste denitration catalyst, then uses sodium hydroxide solution to remove arsenic, and uses sodium hydrosulfide to remove mercury to obtain denitration powder, and then mixes silicate cement, glass fiber, cerium dioxide and the waste denitration powder to prepare a ceramic powder, thereby preparing a denitration catalyst. The above patent not only uses a variety of acids, alkalis and organic liquids to clean and cause secondary environmental pollution, but also does not fundamentally and effectively solve the harmlessness of waste vanadium titanium denitration catalysts, and the market value is not high. Patent CN201510852564.2 uses silicon source powder, aluminum source powder, sintering agent, vanadium element solid solvent and other raw materials to mix with waste denitration catalysts to prepare titanium-based ceramics. Although the above catalyst can completely solve the harmlessness of the catalyst, it can only be used in textile porcelain, building porcelain and other fields with low added value.

[0004] Meanwhile, with the increasingly severe global energy shortage problem, the development and utilization of clean energy are imminent. As a clean, efficient, and renewable energy source, hydrogen is attracting extensive attention from global scientific researchers. The commercial hydrogen production processes mainly include three categories: electrolytic water hydrogen production, coal gasification hydrogen production, and catalytic reforming hydrogen production. Among them, catalytic reforming hydrogen production is one of the hydrogen production processes with the greatest development potential. The catalyst is the core of the catalytic reforming hydrogen production process. The catalyst disclosed in Patent CN20061013084.7, with transition metal mixed oxides as the active component and alumina and magnesia as the composite carrier, has a high ethanol conversion rate, and the hydrogen selectivity reaches 60%. Patent CN96100965.9A discloses a platinum-palladium catalyst for converting gasoline into hydrogen-rich gas. In the hydrogen-rich gas, the hydrogen content is 17% and the methane content is 62%. However, its active component is a noble metal, with a high cost and low hydrogen selectivity. The gasoline oxidative reforming hydrogen production catalyst disclosed in Patent CN01138906.0A, with RuO 2 as the catalytic active component and rare earth element oxides as the co-catalyst, has a hydrogen selectivity of 1.5 - 1.7 mol(H 2 +CO) / mol C at 820 °C, but its reaction temperature is relatively high and the energy consumption is high. Therefore, the main design objectives of the catalyst are to improve the selectivity of the catalyst, reduce the catalyst activity loading, and lower the catalytic reaction temperature. Summary of the Invention

[0005] The objective of the present invention is to provide a 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as the raw material to improve the deficiencies of the existing technology. Another objective of the present invention is to provide the preparation method and application of the above catalyst.

[0006] The objective of the present invention can be achieved through the following technical solutions:

[0007] The present invention modifies ceramic clay through hydrothermal treatment to improve its water retention performance. At the same time, it utilizes the co-catalytic effects of TiO 2 , V 2 O 5 and MoO 3 in the waste denitration catalyst to improve the catalytic performance. Using the mixture of ceramic clay and waste denitration catalyst powder as the catalyst carrier can combine the advantages of both, being both easy to 3D print into shape and having higher catalytic performance. Utilizing the advantages that the active component nickel tungstate has both strong acidity and excellent redox performance, after plasma treatment, it can improve the electron transport performance of the active sites on the catalyst surface and further improve the catalytic performance. Finally, using plasma to enhance catalytic reforming hydrogen production can not only make the reforming hydrogen production reaction proceed at room temperature but also have high conversion rate and high selectivity.

[0008] The specific technical solution of the present invention is as follows:

[0009] A 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material, the catalyst uses improved ceramic clay and waste vanadium-titanium denitration catalyst as carrier, and nickel tungstate micro wires modified by plasma surface as catalytic active component;

[0010] The nickel tungstate micro wires modified by plasma surface are prepared by the following method:

[0011] Add nickel sulfate and sodium carboxymethyl cellulose into deionized water to form a mixed solution, then add sodium tungstate into the mixed solution, after ultrasonic treatment, place it in a hydrothermal reaction kettle for hydrothermal treatment, after hydrothermal treatment, filter and dry to obtain nickel tungstate micro wire powder, place the nickel tungstate micro wire powder in a dielectric barrier discharge plasma reactor for plasma treatment to obtain nickel tungstate micro wires modified by plasma surface;

[0012] The improved ceramic clay is prepared by the following method:

[0013] Add ceramic clay into hydrogen peroxide and deionized water and stir evenly, transfer to a hydrothermal reaction kettle for hydrothermal activation, after hydrothermal activation, filter and dry to obtain the improved ceramic clay;

[0014] Based on the mass of the carrier, the mass percentage content of the catalytic active component is 2% - 5%, and the mass ratio of the improved ceramic clay to the waste vanadium-titanium denitration catalyst is (4 - 6):(1 - 2).

[0015] In the technical solution of the present invention: the mass ratio of nickel sulfate to sodium carboxymethyl cellulose is respectively 1:(3 - 5), and the molar ratio of nickel sulfate to sodium tungstate is 1:(1 - 5).

[0016] In the technical solution of the present invention: in the preparation method of the nickel tungstate micro wires modified by plasma surface: the temperature of hydrothermal treatment is 150 - 180 °C, the time of hydrothermal treatment is 6 - 12 h, the temperature of drying is 60 - 80 °C, and the time of drying is 4 - 6 h;

[0017] The conditions of plasma treatment are to introduce H 2 and Ar as discharge gases, and the volume concentration ratio of H 2 and Ar is 1:(3 - 4), the peak voltage and frequency are respectively 5 - 12 kV and 5 - 10 kHz, and the time of plasma treatment is 30 - 60 min.

[0018] In the technical solution of the present invention: in the preparation method of the improved ceramic clay, the mass concentration of hydrogen peroxide is 3% - 5%, and the mass ratio of hydrogen peroxide to deionized water is 1 - 10:1.

[0019] Preferably, in the improved method for preparing ceramic clay, the mass ratio of ceramic clay to hydrogen peroxide is 1:(4 - 6).

[0020] Preferably, in the improved method for preparing ceramic clay, the temperature of hydrothermal activation is 140 - 160°C, the time of hydrothermal activation is 4 - 6 h, the temperature of drying is 60 - 80°C, and the time of drying is 4 - 6 h.

[0021] In the technical solution of the present invention: the waste vanadium-titanium denitration catalyst uses TiO 2 as the carrier, MoO 3 and V 2 O 5 as the active components, and the rest are additives;

[0022] Among them, the TiO 2 carrier accounts for 70% - 85% of the content of the waste vanadium-titanium denitration catalyst, and the active components MoO 3 and V 2 O 5 account for 3% - 7% and 1% - 3% of the content of the waste vanadium-titanium denitration catalyst respectively.

[0023] A method for preparing the above catalyst, in which the preparation method of the catalyst is to mix and stir the waste vanadium-titanium denitration catalyst powder, deionized water, plasma surface-modified nickel tungstate micro-wires, and the improved ceramic clay to form a slurry, and use a 3D printer to extrude and print to obtain a mud blank, and finally obtain a honeycomb catalyst after drying and calcination;

[0024] Preferably, the mass ratio of the waste vanadium-titanium denitration catalyst powder to deionized water is 1:(1 - 2).

[0025] In the above preparation method: the extrusion printing speed is 20 - 40 mm / s, and the nozzle diameter used for extrusion printing is 0.2 - 1 mm.

[0026] In the above preparation method: the drying temperature is 30 - 40°C, the drying time is 24 - 48 h, the calcination temperature is 700 - 900°C, and the calcination time is 6 - 8 h.

[0027] In the technical solution of the present invention, the application of the catalyst in plasma-enhanced catalytic reforming of organic small molecules to produce hydrogen.

[0028] In the technical solution of the present invention: the organic small molecule is methanol.

[0029] Catalytic reaction conditions and results of the present invention: A single catalyst was placed into a catalyst performance evaluation reaction device. An aqueous methanol solution was pumped into a vaporization chamber at 250 °C by a peristaltic pump (Shanghai Sanotac) at a rate of 0.027 mL / h for vaporization. Argon (25 mL / min) was used to carry the methanol vapor into a dielectric barrier discharge plasma reactor, which operated under conditions of a peak voltage of 9.35 kV and a frequency of 7.71 kHz. The outlet stream of the dielectric barrier discharge plasma reactor passed through a cold trap cooled by an ice-water bath to collect liquid products for on-line analysis, and the composition of the dried gas was analyzed by gas chromatography (GC-9860-5C-NJ, Nanjing Hope Analytical Equipment Co., LTD). The test results showed that within 2 minutes at room temperature, the methanol conversion efficiency and H 2 selectivity were both greater than 90%.

[0030] Advantageous effects:

[0031] In view of the upcoming large amount of waste vanadium-titanium denitration catalysts in China, the lack of advanced safety disposal and resource utilization technologies, as well as the environmental pollution problems of organic pollutants themselves, the present invention innovatively proposes to use waste vanadium-titanium denitration catalysts to prepare 3D printing reforming hydrogen production catalysts, fundamentally solving the problem of a large number of waste vanadium-titanium denitration catalysts and realizing their high-value resource utilization.

[0032] The main basis is that 3D printing can customize a specific macroscopic morphology (honeycomb catalyst), and using a specific macroscopic morphology (as shown in the attachment Figure 2 ) can promote the reaction kinetics and thus improve the catalytic performance. In addition, the titanium dioxide support in the waste vanadium-titanium denitration catalyst accounts for more than 90% of the catalyst powder, and its water retention performance is better, which is beneficial to the loading of catalytic active components. And V 2 O 5 and MoO 3It also has a certain co-catalytic effect and can improve the catalytic performance. However, it is difficult to form a 3D print using only the waste vanadium-titanium denitration catalyst powder. Therefore, using a mixture of ceramic clay and waste denitration catalyst powder as the catalyst carrier can combine the advantages of both, being both easy to 3D print and having higher catalytic performance. The active component nickel tungstate has both strong acidity and excellent redox properties, so it has excellent reforming hydrogen production performance. After plasma treatment, it can improve the electron transport performance of the active sites on the catalyst surface and further enhance the catalytic performance. Finally, although plasma catalysis has the advantage of operating at room temperature, its selectivity is relatively low, while the catalyst has the advantage of high selectivity. Therefore, using plasma-enhanced catalytic reforming for hydrogen production can not only enable the reforming hydrogen production reaction to proceed at room temperature but also have high conversion and selectivity. The successful application of the present invention will not only completely solve the problem of treating waste vanadium-titanium denitration catalysts but also, as a reforming hydrogen production catalyst, greatly solve the energy shortage problem, thus bringing huge economic, environmental, and social benefits. Description of the Drawings

[0033] Figure 1 Scanning electron microscope image of nickel tungstate prepared in Example 1;

[0034] Figure 2 Physical picture of the catalyst prepared in Example 1;

[0035] Figure 3 Methanol conversion efficiency graph of the catalysts prepared in Examples 1 - 3;

[0036] Figure 4 For the catalysts prepared in Examples 1 - 3, the H 2 Selectivity graph; Detailed Description of the Invention

[0037] In the waste vanadium-titanium denitration catalyst used in the examples, TiO 2 is used as the carrier, and MoO 3 and V 2 O 5 are the main active components. Among them, the TiO 2 carrier accounts for 85% of the content of the waste vanadium-titanium denitration catalyst, and the main active components MoO 3 and V 2 O 5 are 7% and 3% of the content of the waste vanadium-titanium denitration catalyst respectively, and the content of other impurities is 5%.

[0038] The following further illustrates the present invention with reference to examples, but the protection scope of the present invention is not limited thereto: Example 1

[0039] (1) Preparation of plasma surface-modified nickel tungstate micro-wires

[0040] 1.515 g of nickel sulfate and 4.545 g of sodium carboxymethyl cellulose were added to 15.150 g of deionized water to form a mixed solution. Then, 14.378 g of sodium tungstate was added to the mixed solution. After ultrasonic treatment for 30 min, the solution was placed in a hydrothermal reaction kettle for hydrothermal treatment. After hydrothermal treatment at 150 °C for 12 h, the solution was filtered and dried at 60 °C for 6 h to obtain nickel tungstate microline powder. The nickel tungstate microline powder was placed in a dielectric barrier discharge plasma reactor for plasma treatment to obtain plasma surface-modified nickel tungstate microline. The conditions for plasma treatment were as follows: H 2 and Ar were used as discharge gases, and the volume concentration ratio of H 2 and Ar was 1:4. The peak voltage and frequency were 5 kV and 10 kHz, respectively, and the plasma treatment time was 30 min, thereby obtaining plasma surface-modified nickel tungstate microline (as shown in Figure 1 );

[0041] (2) Ceramic clay modification

[0042] 40.000 g of ceramic clay was added to 240.000 g of 3% hydrogen peroxide and 40.000 g of deionized water and stirred evenly. Then, the mixture was transferred to a hydrothermal reaction kettle for hydrothermal activation. After hydrothermal activation at 140 °C for 6 h, the mixture was filtered and dried at 80 °C for 4 h to obtain modified ceramic clay;

[0043] (3) Catalyst preparation

[0044] 20 g of waste vanadium-titanium denitration catalyst powder, 20 g of deionized water, 3 g of plasma surface-modified nickel tungstate microline powder prepared in step (1), and 40 g of modified ceramic clay prepared in step (2) were mixed and stirred to form a slurry (the mass percentage content of the catalytic active component was 5%). The slurry was extruded and printed using a 3D printer (SLX-DY2020, Fuliang County Zhibin Pottery Studio) to obtain a green body. The extrusion printing speed was 30 mm / s, and the nozzle diameter used for extrusion printing was 0.6 mm. Finally, the green body was dried at 30 °C for 48 h and calcined at 700 °C for 8 h to obtain a honeycomb catalyst (as shown in Figure 2 );

[0045] (4) Catalytic activity test

[0046] A single catalyst was loaded into the catalyst performance evaluation reaction device, and an aqueous methanol solution was pumped into a vaporization chamber at 250 °C by a peristaltic pump (Shanghai Sanotac) at a rate of 0.027 mL / h for vaporization. The methanol vapor was carried by argon (25 mL / min) into a dielectric barrier discharge plasma reactor, and the reactor was operated under conditions of a peak voltage of 9.35 kV and a frequency of 7.71 kHz. The outlet stream of the dielectric barrier discharge plasma reactor passed through a cold trap cooled by an ice-water bath to collect liquid products for on-line analysis, and the composition of the dry gas was analyzed by gas chromatography (GC-9860-5C-NJ, Nanjing Hope Analytical Equipment Co., LTD). As Figure 3 and Figure 4 shown, the test results show that the methanol conversion efficiency and H 2 selectivity are both greater than 95% at room temperature for 2 min;

[0047] (5) Application scope

[0048] The reforming hydrogen production catalyst prepared by this method is applicable to plasma-enhanced catalytic methanol reforming for hydrogen production at room temperature.

[0049] Example 2

[0050] (1) Preparation of plasma surface-modified nickel tungstate micro wires

[0051] 0.707 g of nickel sulfate and 3.535 g of sodium carboxymethyl cellulose were added to 10.605 g of deionized water to form a mixed solution, and then 1.342 g of sodium tungstate was added to the mixed solution. After ultrasonic treatment for 30 min, it was placed in a hydrothermal reaction kettle for hydrothermal treatment. After hydrothermal treatment at 180 °C for 6 h, it was filtered and dried at 80 °C for 4 h to obtain nickel tungstate micro wire powder. The nickel tungstate micro wire powder was placed in a dielectric barrier discharge plasma reactor for plasma treatment to obtain plasma surface-modified nickel tungstate micro wires, where the conditions for plasma treatment were to introduce H 2 and Ar as discharge gases, and the volume concentration ratio of H 2 and Ar was 1:3, the peak voltage and frequency were 12 kV and 5 kHz respectively, and the plasma treatment time was 60 min, thereby obtaining plasma surface-modified nickel tungstate micro wires;

[0052] (2) Ceramic clay modification

[0053] 60.000 g of ceramic clay was added to 240.000 g of hydrogen peroxide with a mass concentration of 3% and 120.000 g of deionized water and stirred evenly, transferred to a hydrothermal reaction kettle for hydrothermal activation, hydrothermally activated at 160 °C for 4 h and filtered, and dried at 60 °C for 6 h to obtain improved ceramic clay;

[0054] (3) Catalyst preparation

[0055] 10 g of waste vanadium-titanium denitration catalyst powder, 20 g of deionized water, 1.4 g of nickel tungstate microline powder prepared in step (1), and 60 g of improved ceramic clay prepared in step (2) are mixed and stirred to form a slurry (the mass percentage content of the catalytic active component is 2%). A mud embryo is obtained by extrusion printing using a 3D printer (SLX-DY2020, Fuliang County Zhibin Pottery Studio). The extrusion printing speed is 30 mm / s, and the nozzle diameter used for extrusion printing is 0.6 mm. Finally, it is dried at 40 °C for 24 h and calcined at 900 °C for 6 h to obtain a honeycomb catalyst;

[0056] (4) Catalytic activity test

[0057] A single catalyst is placed into a catalyst performance evaluation reaction device. An aqueous methanol solution is pumped into a vaporization chamber at 250 °C at a speed of 0.027 mL / h by a peristaltic pump (Shanghai Sanotac) for vaporization. Argon (25 mL / min) is used to carry the methanol water vapor into a dielectric barrier discharge plasma reactor. The reactor operates under the conditions of a peak voltage of 9.35 kV and a frequency of 7.71 kHz. The outlet flow of the dielectric barrier discharge plasma reactor passes through a cold trap cooled by an ice-water bath to collect liquid products for on-line analysis, and the composition of the dry gas is analyzed by gas chromatography (GC-9860-5C-NJ, Nanjing Hope Analytical Equipment Co.,LTD). As Figure 3 and Figure 4 shown, the test results show that the methanol conversion efficiency and H 2 selectivity are both greater than 90% at room temperature for 2 min;

[0058] (5) Application scope

[0059] The reforming hydrogen production catalyst prepared by this method is applicable to plasma-enhanced catalytic methanol reforming for hydrogen production at room temperature.

[0060] Example 3

[0061] (1) Preparation of plasma surface-modified nickel tungstate microline

[0062] 0.757 g of nickel sulfate and 2.271 g of sodium carboxymethyl cellulose were added to 15.144 g of deionized water to form a mixed solution. Then, 2.876 g of sodium tungstate was added to the mixed solution. After ultrasonic treatment for 30 min, the solution was placed in a hydrothermal reaction kettle for hydrothermal treatment. After hydrothermal treatment at 160 °C for 10 h, the solution was filtered and dried at 70 °C for 5 h to obtain nickel tungstate micro-wire powder. The nickel tungstate micro-wire powder was placed in a dielectric barrier discharge plasma reactor for plasma treatment to obtain plasma surface-modified nickel tungstate micro-wires. The conditions for plasma treatment were as follows: H 2 and Ar were used as discharge gases, and the volume concentration ratio of H 2 and Ar was 1:3. The peak voltage and frequency were 8 kV and 7 kHz, respectively, and the plasma treatment time was 40 min, thereby obtaining plasma surface-modified nickel tungstate micro-wires;

[0063] (2) Ceramic clay modification

[0064] 40.000 g of ceramic clay was added to 200.000 g of hydrogen peroxide with a mass concentration of 5% and 60.000 g of deionized water, and the mixture was stirred evenly. Then, it was transferred to a hydrothermal reaction kettle for hydrothermal activation. After hydrothermal activation at 150 °C for 5 h, the solution was filtered and dried at 70 °C for 5 h to obtain modified ceramic clay;

[0065] (3) Catalyst preparation

[0066] 10 g of waste vanadium-titanium denitration catalyst powder, 15 g of deionized water, 1.5 g of nickel tungstate micro-wire powder prepared in step (1), and 40 g of modified ceramic clay prepared in step (2) were mixed and stirred to form a slurry (the mass percentage content of the catalytic active component was 3%). The slurry was extruded and printed using a 3D printer (SLX-DY2020, Fuliang County Zhibin Pottery Studio) to obtain a mud blank. The extrusion printing speed was 30 mm / s, and the nozzle diameter used for extrusion printing was 0.6 mm. Finally, it was dried at 35 °C for 36 h and calcined at 800 °C for 7 h to obtain a honeycomb catalyst;

[0067] (4) Catalytic activity test

[0068] A single catalyst was loaded into the catalyst performance evaluation reaction device, and an aqueous methanol solution was pumped into a vaporization chamber at 250 °C by a peristaltic pump (Shanghai Sanotac) at a rate of 0.027 mL / h for vaporization. Argon (25 mL / min) was used to carry the methanol vapor into a dielectric barrier discharge plasma reactor, and the reactor was operated under conditions of a peak voltage of 9.35 kV and a frequency of 7.71 kHz. The outlet stream of the dielectric barrier discharge plasma reactor passed through a cold trap cooled by an ice-water bath to collect liquid products for on-line analysis, and the composition of the dry gas was analyzed by gas chromatography (GC-9860-5C-NJ, Nanjing Hope Analytical Equipment Co., LTD). As Figure 3 and Figure 4 shown, the test results show that the methanol conversion efficiency and H 2 selectivity are both greater than 92% at room temperature for 2 min;

[0069] (5) Scope of application

[0070] The reforming hydrogen production catalyst prepared by this method is applicable to plasma-enhanced catalytic methanol reforming for hydrogen production at room temperature.

[0071] Comparative Example 1

[0072] (1) Preparation of catalyst

[0073] Except that sodium tungstate was not added in step (1) during the catalyst preparation, other conditions were the same as in Example 1;

[0074] (2) Catalyst activity test

[0075] A single catalyst was loaded into the catalyst performance evaluation reaction device, and an aqueous methanol solution was pumped into a vaporization chamber at 250 °C by a peristaltic pump (Shanghai Sanotac) at a rate of 0.027 mL / h for vaporization. Argon (25 mL / min) was used to carry the methanol vapor into a dielectric barrier discharge plasma reactor, and the reactor was operated under conditions of a peak voltage of 9.35 kV and a frequency of 7.71 kHz. The outlet stream of the dielectric barrier discharge plasma reactor passed through a cold trap cooled by an ice-water bath to collect liquid products for on-line analysis, and the composition of the dry gas was analyzed by gas chromatography (GC-9860-5C-NJ, Nanjing Hope Analytical Equipment Co., LTD). As Figure 3 and Figure 4 shown, the test results show that the methanol conversion efficiency and H 2 selectivity are respectively lower than 62% and 71% at room temperature for 2 min;

[0076] (3) Comparative effect

[0077] Compared with Example 1, when preparing the catalyst, sodium tungstate is not added in step (1), and the nickel tungstate active component cannot be formed in the catalyst, resulting in a decrease in catalytic performance.

[0078] Comparative Example 2

[0079] (1) Preparation of the catalyst

[0080] Except that the waste vanadium-titanium denitration catalyst powder is not added in step (3) during the preparation of the catalyst, other conditions are the same as in Example 2;

[0081] (2) Catalyst activity test

[0082] A single catalyst was placed into the catalyst performance evaluation reaction device, and the methanol aqueous solution was pumped into the vaporization chamber at 250 °C at a rate of 0.027 mL / h by a peristaltic pump (Shanghai Sanotac) for vaporization. Argon (25 mL / min) was used to carry the methanol steam into the dielectric barrier discharge plasma reactor, and the reactor was operated under the conditions of a peak voltage of 9.35 kV and a frequency of 7.71 kHz. The outlet stream of the dielectric barrier discharge plasma reactor passed through a cold trap cooled by an ice-water bath to collect the liquid product for on-line analysis, and the composition of the dry gas was analyzed by gas chromatography (GC-9860-5C-NJ, Nanjing Hope Analytical Equipment Co., LTD). As Figure 3 and Figure 4 shown, the test results show that at room temperature, the methanol conversion efficiency and H 2 selectivity are respectively lower than 48% and 55% within 2 min;

[0083] (3) Comparative effect

[0084] Compared with Example 2, when preparing the catalyst, the waste vanadium-titanium denitration catalyst powder is not added in step (1), and only ceramic clay is used as the carrier. The decrease in its specific surface area leads to a decrease in the plasma catalytic effect, and there is no TiO 2 , MoO 3 and V 2 O 5 as a promoter, and the catalytic performance decreases significantly.

Claims

1. A 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material, Characterized in that: This catalyst uses improved ceramic clay and waste vanadium-titanium denitration catalyst as carriers, and nickel tungstate micro wires with plasma surface modification as catalytic active components; The nickel tungstate micro wires with plasma surface modification are prepared by the following method: Nickel sulfate and sodium carboxymethyl cellulose were added to deionized water to form a mixed solution, and then sodium tungstate was added to the mixed solution. After ultrasonic treatment, it was placed in a hydrothermal reaction kettle for hydrothermal treatment. After hydrothermal treatment, it was filtered and dried to obtain nickel tungstate microline powder. The nickel tungstate microline powder was placed in a dielectric barrier discharge plasma reactor for plasma treatment to obtain plasma surface-modified nickel tungstate microlines; the conditions for plasma treatment were to introduce H 2 and Ar as discharge gases; The improved ceramic clay is prepared by the following method: Add ceramic clay into hydrogen peroxide and deionized water and stir evenly, transfer to a hydrothermal reaction kettle for hydrothermal activation, and obtain the improved ceramic clay after hydrothermal activation, filtration and drying; Based on the mass of the carrier, the mass percentage content of the catalytic active component is 2% - 5%, and the mass ratio of the improved ceramic clay to the waste vanadium-titanium denitration catalyst is (4 - 6):(1 - 2).

2. The 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, Characterized in that: The mass ratios of nickel sulfate and sodium carboxymethylcellulose are respectively 1:(3 - 5), and the molar ratio of nickel sulfate to sodium tungstate is 1:(1 - 5).

3. The 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, Characterized in that: In the preparation method of the nickel tungstate micro wires with plasma surface modification: the temperature of hydrothermal treatment is 150 - 180 °C, the time of hydrothermal treatment is 6 - 12 h, the temperature of drying is 60 - 80 °C, and the time of drying is 4 - 6 h; H 2 The volume concentration ratio of H and Ar is 1:(3 - 4), the peak voltage and frequency are 5 - 12 kV and 5 - 10 kHz respectively, and the plasma treatment time is 30 - 60 min.

4. The 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, Characterized in that: In the preparation method of the improved ceramic clay, the mass concentration of hydrogen peroxide is 3% - 5%, and the mass ratio of hydrogen peroxide to deionized water is 1 - 10:

1.

5. The 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, Characterized in that: In the preparation method of the improved ceramic clay, the mass ratio of ceramic clay to hydrogen peroxide is 1:(4 - 6).

6. The 3D printing reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, Characterized in that: In the preparation method of the improved ceramic clay, the temperature of hydrothermal activation is 140 - 160 °C, the time of hydrothermal activation is 4 - 6 h, the temperature of drying is 60 - 80 °C, and the time of drying is 4 - 6 h.

7. The catalyst according to claim 1, Characterized in that: The waste vanadium-titanium denitration catalyst uses TiO 2 as the carrier, MoO 3 and V 2 O 5 as the active components, and the rest are additives; Among them, TiO 2 The carrier is 70% - 85% of the content of waste vanadium-titanium denitration catalyst, and the active components MoO 3 and V 2 O 5 are 3% - 7% and 1% - 3% of the content of waste vanadium-titanium denitration catalyst respectively.

8. A preparation method of the catalyst according to claim 1, Characterized in that: The preparation method of this catalyst is to mix and stir waste vanadium-titanium denitration catalyst powder, deionized water, nickel tungstate micro wires with plasma surface modification, and improved ceramic clay to make a slurry, extrude and print with a 3D printer to obtain a mud blank, and finally obtain a honeycomb catalyst after drying and roasting.

9. The preparation method according to claim 8, Characterized in that: The mass ratio of the waste vanadium-titanium denitration catalyst powder to deionized water is 1:(1 - 2).

10. The preparation method according to claim 8, Characterized in that: The extrusion printing speed is 20 - 40 mm / s, and the nozzle diameter used for extrusion printing is 0.2 - 1 mm.

11. According to the preparation method described in claim 8, it is characterized in that: The drying temperature is 30 - 40 °C, the drying time is 24 - 48 h, the calcination temperature is 700 - 900 °C, and the calcination time is 6 - 8 h.

12. Application of the catalyst described in claim 1 in plasma-enhanced catalytic reforming of organic small molecules for hydrogen production.

13. According to the application described in claim 12, it is characterized in that the organic small molecule is methanol.

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