A method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material and its application

Abstract

The present invention discloses a method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material and its application. The preparation method comprises the following steps: crushing the waste vanadium-titanium denitration catalyst and dispersing it in a NaBH4 solution; heating and stirring the reaction, filtering, and drying; mixing the resulting product with a forming agent and a pore-forming agent; granulating and calcining the resulting product to obtain a porous support; mixing the porous support with a fluorine-containing ionic liquid, subjecting the resultant to solvent thermal treatment, separation, and calcination to obtain a hydroxyl-rich porous support; mixing the hydroxyl-rich porous support with an amino-containing silane coupling agent and subjecting it to an amination treatment to obtain an amination porous support; reacting the amination porous support with a carboxyl-containing compound to obtain a carboxyl-grafted porous support; immersing the carboxyl-grafted porous support in a nickel salt solution and ultrasonically treating the solution; and then drying and calcining the solution to obtain a Ni-based reforming hydrogen production catalyst. The above preparation method can fully disperse the active center Ni on the porous support, thereby improving the efficiency of hydrogen production from methane steam reforming.

Description

Technical Field

[0001] The present invention relates to a method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material and application thereof, belonging to the technical fields of environmental protection catalysis and new energy. Background Art

[0002] With the rapid development of industrialization, large-scale emissions of nitrogen oxides have caused numerous atmospheric pollution problems, including acid rain, photochemical smog, and haze. Selective redox technology (SCR) has been widely used in the field of denitrification. Vanadium-titanium denitrification catalysts are commonly used in SCR denitrification processes. These catalysts can typically be regenerated two to three times before being completely discarded. Therefore, the resource utilization of spent vanadium-titanium denitrification catalysts has become an urgent environmental challenge.

[0003] Hydrogen is an important green renewable energy source with the advantages of high calorific value and, in theory, clean combustion, with water as the only combustion product. Methane reforming, such as steam methane reforming and methane-CO2 reforming, is an economical and efficient method for producing hydrogen. Steam methane reforming is the most widely used and has been industrialized on a large scale, producing approximately 100% of the world's hydrogen.

[0004] Supports play a crucial role in methane reforming hydrogen production catalysts. They not only provide physical support for the metal active components but also strongly interact with them, influencing catalyst performance. Some supports even directly participate in the reaction. Thermodynamic calculations show that methane reforming hydrogen production requires high temperatures to achieve sufficiently high hydrogen yields. Therefore, both steam reforming and dry gas reforming require catalyst supports with high thermal stability.

[0005] Ni-based catalysts have high initial activity in methane reforming to produce hydrogen, but poor Ni particle dispersion can easily lead to catalyst deactivation. Therefore, improving the dispersion of the active Ni center within the support is a key challenge. Spent vanadium-titanium denitrification catalysts contain 70-85% titanium dioxide and exhibit excellent thermal stability, making them suitable supports for Ni-based catalysts. However, further improving the dispersion of the active Ni center within the support remains a challenge for existing technologies. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a reforming hydrogen production catalyst using waste vanadium titanium denitration catalyst as raw material and its application. The waste vanadium titanium denitration catalyst is recycled to prepare a porous carrier, which is then subjected to hydroxyl-enriched treatment, amino modification, carboxyl grafting, ion exchange with nickel salt, and calcination, so that Ni can be fully dispersed and loaded on the porous carrier, thereby improving its reforming hydrogen production efficiency.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material comprises the following steps:

[0009] S1. The waste vanadium-titanium denitration catalyst is crushed and dispersed in a NaBH4 solution. After heating and stirring, the reaction is filtered and dried. The resulting product is then mixed with a forming agent and a pore-forming agent, and then granulated and calcined to obtain a porous carrier.

[0010] S2, mixing the porous support and the fluorine-containing ionic liquid, heating, separating, drying, and calcining to obtain a hydroxyl-rich porous support;

[0011] S3, mixing the hydroxyl-rich porous support with an amino-containing silane coupling agent and performing an amination treatment to obtain an amination porous support; and then reacting the amination porous support with a carboxyl-containing compound to obtain a carboxyl-grafted porous support;

[0012] S4. Immersing the carboxyl-grafted porous support in a nickel salt solution and ultrasonically treating the support, followed by separation, drying, and calcination to obtain a Ni-based reforming hydrogen production catalyst.

[0013] Preferably, the waste vanadium titanium denitrification catalyst uses TiO2 as a carrier, V2O5 and WO3 as active components, and the rest are co-catalysts; wherein, the TiO2 carrier is 70% to 85% of the content of the waste vanadium titanium denitrification catalyst, and the active components V2O5 and WO3 are 1% to 4% and 1% to 3% of the content of the waste vanadium denitrification catalyst, respectively.

[0014] Preferably, in step S1, the concentration of the NaBH4 solution is 10-15%;

[0015] The mixing ratio of the crushed vanadium titanium denitrification catalyst and the NaBH4 solution is (3-5) g: (10-20) ml;

[0016] The conditions for the heating and stirring reaction are: temperature 50-70°C, rotation speed 50-100 rpm, 0.5-1.5h;

[0017] Drying conditions are: 85-120℃, 1-3h.

[0018] Preferably, in step S1, the forming agent is a 1-15 wt% poly(ethylene) acid solution;

[0019] The pore-forming agent is a 10-20 wt% urea solution;

[0020] The mass ratio of the obtained product to the forming agent and the pore-forming agent is (50-65):(3-10):(2-7);

[0021] The calcination conditions are: 1000-1250°C, 1-2.5h.

[0022] Preferably, in step S2, the fluorine-containing ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]);

[0023] The mass ratio of the porous support to the fluorine-containing ionic liquid is (1-3):(5-8);

[0024] Heating conditions are: 150-200°C, 15-25h;

[0025] The calcination conditions are: 700-900°C, 1-2.5h.

[0026] Preferably, in step S3, the specific preparation method of the amination porous carrier is:

[0027] Mix the hydroxyl-rich porous carrier, amino-containing silane coupling agent, and anhydrous ethanol in a mass ratio of (2-4):1:(10-15), stir at room temperature for 10-15 minutes, let stand for 1-1.5 hours, filter, and dry the filter residue at 100-120°C for 1-2 hours;

[0028] Wherein, the amino-containing silane coupling agent is (3-aminopropyl)triethoxysilane.

[0029] Preferably, in step S3, the specific preparation method of the carboxyl-grafted porous carrier is:

[0030] The amino porous carrier, the carboxyl-containing compound, and DMF are mixed in a mass ratio of (2-5):(1-2):(10-20), stirred at room temperature for 15-25 minutes, allowed to stand for 1-2 hours, filtered, and the residue is dried at 110-130°C for 2-3 hours;

[0031] Wherein, the carboxyl group-containing compound is succinic anhydride.

[0032] Preferably, in step S4, the nickel salt is NiCl2·6H2O or Ni(NO3)2·6H2O or NiSO4·6H2O;

[0033] The mass ratio of the carboxyl-grafted porous carrier to the nickel salt in the nickel salt solution is (8-12):(1-3).

[0034] Preferably, in step S4, the conditions for ultrasonic treatment are: 20-50 kHz, 0.5-1 h;

[0035] Drying conditions are: 70-90℃, 1-1.5h;

[0036] The calcination conditions are: 1100-1250°C, 0.5-2h.

[0037] A reforming hydrogen production catalyst is prepared by any of the above methods.

[0038] The reforming hydrogen production catalyst prepared by any of the above methods or the use of the above reforming hydrogen production catalyst in methane steam reforming hydrogen production.

[0039] The beneficial effects of the present invention are:

[0040] The number of oxygen vacancies in the spent vanadium-titanium denitrification catalyst will decrease due to deactivation and other reasons. Therefore, the crushed spent vanadium-titanium denitrification catalyst is first reduced with NaBH4 to increase the number of oxygen vacancies, and then mixed with a forming agent and a pore-forming agent to form granules and calcined to obtain a porous carrier; during the calcination process, the pore-forming agent will generate gas to break through the powder and form a pore structure, which can then increase the specific surface area of ​​the porous carrier, which is beneficial to the subsequent distribution of nickel.

[0041] The increase in oxygen vacancies facilitates the hydroxylation of the porous support. Fluoride ions in the ammonium fluoride ionic liquid interact with oxygen vacancies on the titanium dioxide surface, promoting the adsorption and dissociation of water molecules on the surface. The hydroxyl groups generated by the dissociation of the water molecules bind to the titanium dioxide surface, forming a hydroxyl-rich surface structure. Following the hydroxylation treatment, amination and carboxylation grafting are performed sequentially. Finally, nickel ions are loaded onto the porous support via ion exchange. After calcination, a Ni-based reforming hydrogen production catalyst with fully dispersed active centers is obtained. Due to the well-dispersed active centers, the catalyst exhibits excellent catalytic performance in methane steam reforming hydrogen production. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is the methane conversion rate of the catalysts obtained in Example 1 and Comparative Examples 1-3;

[0043] Figure 2 The figure is a graph showing the change in methane conversion rate of the catalyst obtained in Example 1 versus reaction time. DETAILED DESCRIPTION

[0044] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0045] Example 1

[0046] A waste vanadium-titanium denitration catalyst (TiO2 content 80%, V2O5 content 3%, WO3 content 2%) was crushed and sieved to obtain 100-150 mesh fine particles (30g). The particles were then dispersed in 200ml of a 15% NaBH4 solution, stirred at 55°C, 100 rpm for 1 hour, and filtered. The residue was then dried at 100°C for 1.5 hours. A 25g mixture was mixed with 5g of a 15wt% poly(ethylene oxide) solution and 3g of a 20wt% urea solution, granulated, and calcined at 1100°C for 2 hours to obtain a porous support.

[0047] Take 20g of the porous carrier and mix it with 50ml of 1-butyl-3-methylimidazolium tetrafluoroborate, 50ml of acetic acid and 50ml of deionized water, treat it at 180℃ for 24h, separate it after treatment, and dry it. The resulting product is calcined at 850℃ for 2h and then cooled to room temperature. Then, it is mixed with 10g of (3-aminopropyl)triethoxysilane and 120g of anhydrous ethanol and stirred for 15min and then allowed to stand for 1.5h. After standing, it is filtered. The filter residue is dried at 100℃ for 1h and then cooled to room temperature. Then, it is mixed with 11g of succinic anhydride and 150g of DMF and stirred for 120min and then allowed to stand for 2h. After standing, it is filtered. The filter residue is dried at 110℃ for 2h to obtain a carboxyl-grafted porous carrier.

[0048] 20 g of the carboxyl-grafted porous support was immersed in 100 ml of an aqueous solution containing 3 g of Ni(NO3)2·6H2O and treated with ultrasound (30 kHz) for 1 h. After separation, it was dried at 75°C for 1.5 h and then calcined at 1100°C for 2 h to obtain a Ni-based reforming hydrogen production catalyst.

[0049] Comparative Example 1

[0050] The method is basically the same as Example 1, except that in Example 1, the crushed waste vanadium-titanium denitration catalyst is not subjected to reduction treatment.

[0051] Specifically:

[0052] The waste vanadium-titanium denitrification catalyst (TiO2 content 80%, V2O5 content 3%, WO3 content 2%) was crushed and screened into 25g of 100-150 mesh fine particles, which were evenly mixed with 5g of 15wt% polyacrylic acid solution and 3g of 20wt% urea solution, and then granulated. The mixture was then calcined at 1100°C for 2h to obtain a porous carrier.

[0053] Take 20g of the porous carrier and mix it with 50ml of 1-butyl-3-methylimidazolium tetrafluoroborate, 50ml of acetic acid and 50ml of deionized water, treat it at 180℃ for 24h, separate it after treatment, and dry it. The resulting product is calcined at 850℃ for 2h and then cooled to room temperature. Then, it is mixed with 10g of (3-aminopropyl)triethoxysilane and 120g of anhydrous ethanol and stirred for 15min and then allowed to stand for 1.5h. After standing, it is filtered. The filter residue is dried at 100℃ for 1h and then cooled to room temperature. Then, it is mixed with 11g of succinic anhydride and 150g of DMF and stirred for 120min and then allowed to stand for 2h. After standing, it is filtered. The filter residue is dried at 110℃ for 2h to obtain a carboxyl-grafted porous carrier.

[0054] 20 g of the carboxyl-grafted porous support was immersed in 100 ml of an aqueous solution containing 3 g of Ni(NO3)2·6H2O and treated with ultrasound (30 kHz) for 1 h. After separation, it was dried at 75°C for 1.5 h and then calcined at 1100°C for 2 h to obtain a Ni-based reforming hydrogen production catalyst.

[0055] Comparative Example 2

[0056] The method is basically the same as Example 1, except that in Comparative Example 2, the hydroxyl-rich porous carrier is not subjected to amination treatment.

[0057] Specifically:

[0058] A waste vanadium-titanium denitration catalyst (TiO2 content 80%, V2O5 content 3%, WO3 content 2%) was crushed and sieved to obtain 100-150 mesh fine particles (30g). The particles were then dispersed in 200ml of a 15% NaBH4 solution, stirred at 55°C, 100 rpm for 1 hour, and filtered. The residue was then dried at 100°C for 1.5 hours. A 25g mixture was mixed with 5g of a 15wt% poly(ethylene oxide) solution and 3g of a 20wt% urea solution, granulated, and calcined at 1100°C for 2 hours to obtain a porous support.

[0059] 20 g of the porous support was mixed with 50 ml of 1-butyl-3-methylimidazolium tetrafluoroborate, 50 ml of acetic acid and 50 ml of deionized water, and treated at 180 ° C for 24 h. After treatment, it was separated and dried. The resulting product was calcined at 850 ° C for 2 h and then cooled to room temperature. It was then mixed with 11 g of succinic anhydride and 150 g of DMF and stirred for 120 min and then allowed to stand for 2 h. After standing, it was filtered. The filter residue was dried at 110 ° C for 2 h and then cooled to room temperature. Then 20 g of the above product was immersed in 100 ml of an aqueous solution containing 3 g of Ni(NO3)2·6H2O and treated with ultrasound (30 kHz) for 1 h. After separation, it was dried at 75 ° C for 1.5 h and then calcined at 1100 ° C for 2 h to obtain a Ni-based reforming hydrogen production catalyst.

[0060] Comparative Example 3

[0061] The method is basically the same as Example 1, except that in Comparative Example 3, the amino-modified porous carrier is not subjected to carboxyl grafting treatment.

[0062] Specifically:

[0063] A waste vanadium-titanium denitration catalyst (TiO2 content 80%, V2O5 content 3%, WO3 content 2%) was crushed and sieved to obtain 100-150 mesh fine particles (30g). The particles were then dispersed in 200ml of a 15% NaBH4 solution, stirred at 55°C, 100 rpm for 1 hour, and filtered. The residue was then dried at 100°C for 1.5 hours. A 25g mixture was mixed with 5g of a 15wt% poly(ethylene oxide) solution and 3g of a 20wt% urea solution, granulated, and calcined at 1100°C for 2 hours to obtain a porous support.

[0064] Take 20g of the porous carrier and mix it with 50ml of 1-butyl-3-methylimidazolium tetrafluoroborate, 50ml of acetic acid and 50ml of deionized water, treat it at 180°C for 24h, separate it after treatment, and dry it. The resulting product is calcined at 850°C for 2h and then cooled to room temperature. Then, it is mixed with 10g of (3-aminopropyl)triethoxysilane and 120g of anhydrous ethanol and stirred for 15min and then allowed to stand for 1.5h. After standing, it is filtered and the filter residue is dried at 100°C for 1h and then cooled to room temperature to obtain an amino porous carrier.

[0065] 20 g of the amino-modified porous support was immersed in 100 ml of an aqueous solution containing 3 g of Ni(NO3)2·6H2O and treated with ultrasound (30 kHz) for 1 h. After separation, it was dried at 75°C for 1.5 h and then calcined at 1100°C for 2 h to obtain a Ni-based reforming hydrogen production catalyst.

[0066] The atmospheric pressure activity evaluation of the methane steam reforming hydrogen production catalyst was carried out in a fixed-bed stainless steel tube reactor (ID = 8mm). The catalyst loading was 100mg, and the catalyst was pretreated at 800℃ for 2h in a 10% H2 / Ar atmosphere with a reducing gas flow rate of 60mL / min. The reaction raw materials were pure methane (99.99%) and deionized water. The deionized water was first injected into a 200℃ preheating furnace for vaporization through a high-pressure circulating water pump with an injection rate of 0.064mL / min. 40mL / min of methane gas was introduced and mixed with the water vapor formed by the deionized water before entering the reactor for reaction. The reaction mass space velocity was 72000mL·h -1 ·gcat -1The reaction off-gas was cooled in an ice-water bath and then analyzed online on a GC9310 gas chromatograph. Argon (99.9%) was used as the carrier gas, the TCD detector was set at a bridge flow of 80 mA, and the column temperature was 110°C. The chromatographic column was a TDX-01 columnar molecular sieve (2 μm). Data were collected on an N2000 chromatographic workstation, and the reaction conversion was calculated by the area normalization method.

[0067] The catalytic activity of the Ni-based reforming hydrogen production catalysts obtained in Example 1 and Comparative Examples 1-3 at atmospheric pressure reforming at different reaction temperatures is as follows: Figure 1 As shown, the methane conversion rate of the catalyst increases with the increase of temperature, and the Ni-based reforming hydrogen production catalyst obtained in Example 1 shows the best methane conversion rate (99.7%). The reason is that the reduction treatment of NaBH4 can increase the number of oxygen vacancies and is conducive to the hydroxylation of the porous carrier. The hydroxylation-rich structure is conducive to the dispersion of amino groups. Therefore, during the carboxylation grafting treatment, (3-aminopropyl) triethoxysilane can combine with the amino groups dispersed on the porous carrier and introduce the carboxyl groups into the porous carrier. The dispersion of the carboxyl groups can increase the dispersion of nickel ions when the nickel ions are loaded onto the porous carrier through ion exchange. Therefore, the active center Ni of the Ni-based reforming hydrogen production catalyst obtained after calcination will be fully dispersed, and it will show excellent catalytic performance in methane steam reforming hydrogen production. And from Figure 2 It can be seen that the activity of the Ni-based reforming hydrogen production catalyst prepared in Example 1 is relatively stable in the 200h stability experiment, without large fluctuations or obvious decline.

[0068] The above is only a preferred embodiment of the patent of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the patent of the present invention. These improvements and modifications should also be regarded as the scope of protection of the patent of the present invention.

Claims

1. A method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material, characterized in that: The steps include: S1. The waste vanadium-titanium denitration catalyst is crushed and dispersed in a NaBH4 solution. After heating and stirring, the reaction is filtered and dried. The resulting product is then mixed with a forming agent and a pore-forming agent, and then granulated and calcined to obtain a porous carrier. S2. After mixing the porous support, fluorine-containing ionic liquid, water and acetic acid, heating, separating, drying and calcining to obtain a hydroxyl-rich porous support, the heating conditions are: 150-200° C., 15-25 h; S3, mixing the hydroxyl-rich porous support with an amino-containing silane coupling agent and performing an amination treatment to obtain an amination porous support; and then reacting the amination porous support with a carboxyl-containing compound to obtain a carboxyl-grafted porous support; S4. Immersing the carboxyl-grafted porous support in a nickel salt solution and ultrasonically treating the support, followed by separation, drying, and calcination to obtain a Ni-based reforming hydrogen production catalyst.

2. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S1, the concentration of the NaBH4 solution is 10-15%; The mixing ratio of the crushed vanadium titanium denitrification catalyst and the NaBH4 solution is (3-5) g: (10-20) ml; The conditions for the heating and stirring reaction are: temperature 50-70°C, rotation speed 50-100 rpm, 0.5-1.5h; Drying conditions are: 85-120℃, 1-3h.

3. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S1, the forming agent is a 1-15 wt% poly(ethylene) acid solution; The pore-forming agent is a 10-20 wt% urea solution; The mass ratio of the obtained product to the forming agent and the pore-forming agent is (50-65):(3-10):(2-7); The calcination conditions are: 1000-1250°C, 1-2.5h.

4. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S2, the fluorine-containing ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate; The mass ratio of the porous support to the fluorine-containing ionic liquid is (1-3):(5-8); The calcination conditions are: 700-900°C, 1-2.5h.

5. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S3, the specific preparation method of the amination porous carrier is: Mix the hydroxyl-rich porous carrier, amino-containing silane coupling agent, and anhydrous ethanol in a mass ratio of (2-4):1:(10-15), stir at room temperature for 10-15 minutes, let stand for 1-1.5 hours, filter, and dry the filter residue at 100-120°C for 1-2 hours; Wherein, the amino-containing silane coupling agent is (3-aminopropyl)triethoxysilane.

6. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S3, the specific preparation method of the carboxyl-grafted porous carrier is: The amino porous carrier, the carboxyl-containing compound, and DMF are mixed in a mass ratio of (2-5):(1-2):(10-20), stirred at room temperature for 15-25 minutes, allowed to stand for 1-2 hours, filtered, and the residue is dried at 110-130°C for 2-3 hours; Wherein, the carboxyl group-containing compound is succinic anhydride.

7. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S4, the nickel salt is NiCl2·6H2O or Ni(NO3)2·6H2O or NiSO4·6H2O; The mass ratio of the carboxyl-grafted porous carrier to the nickel salt in the nickel salt solution is (8-12):(1-3).

8. The method for preparing a reforming hydrogen production catalyst using waste vanadium-titanium denitration catalyst as raw material according to claim 1, characterized in that: In step S4, the ultrasonic treatment conditions are: 20-50 kHz, 0.5-1 h; Drying conditions are: 70-90℃, 1-1.5h; The calcination conditions are: 1100-1250°C, 0.5-2h.

9. A reforming hydrogen production catalyst, characterized in that The method is prepared by any one of claims 1 to 8.

10. Use of the reforming hydrogen production catalyst prepared by the method according to any one of claims 1 to 8 or the reforming hydrogen production catalyst according to claim 9 in hydrogen production by steam reforming of methane.

Images