An industrial platinum group metal deoxidizing catalyst, its preparation method and application

Abstract

The application discloses an industrial platinum group metal deoxidation catalyst, which comprises an active component and a carrier; the active component is one or a combination of two or more of ruthenium, rhodium, palladium, osmium, iridium and platinum, and the content of the active component is 0.02-0.4 wt% of the weight of the carrier; and the carrier is a gamma-alumina ball with a specific surface area of not less than 200 m 2 / g, a pore volume of 0.3-0.6 mL / g and a particle size range of 3-6 mm. The industrial platinum group metal deoxidation catalyst provided by the application adopts cheap and readily available industrial gamma-alumina balls as the carrier, and the high specific surface area of the gamma-alumina balls improves the deoxidation performance of the deoxidation catalyst, so that the deoxidation reaction can be smoothly carried out at low temperature and normal pressure; and the catalyst still has high-precision deep deoxidation effect on trace oxygen of 300-500 ppm in industrial hydrogen under the condition that the space velocity is greater than or equal to 10000 h ‑1 , so that the outlet oxygen is less than 1.0 ppm, and the catalyst is suitable for large-scale and efficient deoxidation of industrial hydrogen in industrial production.

Description

Technical Field

[0001] This invention belongs to the field of gas purification, specifically relating to an industrial deoxygenation catalyst. Background Technology

[0002] Compared to fossil fuels, hydrogen energy is considered a sustainable green energy system with advantages such as wide availability, renewability, zero carbon emissions, and zero environmental pollution. As a secondary energy source, hydrogen must be produced. Currently, new hydrogen production technologies include: fuel reforming, water electrolysis, by-product hydrogen production, bio-hydrogen production, and natural gas reforming. Currently, using water electrolysis for hydrogen production is a commonly used industrial method. The most mature technology is high-temperature alkaline electrolysis, which is widely used in new energy, chemical, hydrogen metallurgy, hydrogen refueling stations, power, and aviation industries. However, in alkaline water electrolysis, the produced hydrogen contains trace amounts of oxygen, which poses several problems for hydrogen applications. For example, in the chemical, metallurgical, and electronics industries, unremoved trace oxygen in the hydrogen can easily poison downstream catalysts or products.

[0003] Currently, there are three common deoxygenation methods used in industry: catalytic deoxygenation, chemical adsorption deoxygenation, and high-temperature activated carbon deoxygenation. Catalytic deoxygenation is the main method currently used. In the presence of hydrogen, oxygen and hydrogen in the gas combine to form water under the action of a deoxygenation catalyst, thus removing the oxygen. However, the copper-based and nickel-chromium alloy deoxygenation catalysts commonly used in the past required high temperature and high pressure during the catalytic deoxygenation process. This reaction condition not only increases energy consumption but also poses safety risks during operation.

[0004] Among existing reports on low-temperature deoxygenation catalysts, CN110721707 discloses a low-temperature deoxygenation catalyst for syngas, which uses α-alumina as a support, palladium as the active component, and adds a non-precious metal composite oxide as an auxiliary agent. This catalyst is effective for syngas with an oxygen content of 0.2 vol% at a temperature of 40°C, a pressure of 2.5 MPa, and a space velocity of 4000 h⁻¹. -1 The deoxygenation reaction is carried out under certain conditions. However, this catalyst requires deep deoxygenation under pressure and low space velocity, resulting in a long gas residence time and a small processing capacity. CN111215060 discloses a supported platinum group metal single-atom catalyst for deoxygenation of hydrogen-containing gas with an oxygen content of 0.3 vol% at low temperature and atmospheric pressure, and a space velocity of 7000 h⁻¹. -1 Deep deoxidation can be carried out under these conditions. Although the deoxidation reaction of this catalyst can be carried out at low temperature and atmospheric pressure, the space velocity is low, and the preparation process of this catalyst is relatively complicated and energy-intensive, limiting it to the preparation of small batches of samples in the laboratory. Therefore, it is of great significance to develop a highly active low-temperature and atmospheric-pressure deoxidation catalyst suitable for industrial production. Summary of the Invention

[0005] To address the problems of complex preparation processes, high costs, and low deoxygenation reaction efficiency in existing deoxygenation catalysts, the present invention aims to provide an industrial platinum group metal deoxygenation catalyst and its preparation method. This catalyst has low production costs, high deoxygenation efficiency, and is suitable for large-scale industrial production and application. To achieve the above objective, the first aspect of the present invention provides an industrial platinum group metal deoxygenation catalyst, comprising an active component and a support; the active component is a platinum group metal, specifically one or more of ruthenium, rhodium, palladium, osmium, iridium, and platinum; the content of the active component is 0.02–0.4 wt% of the support weight; the support is γ-alumina spheres with a specific surface area of ​​not less than 200 m². 2 / g, pore volume is 0.3~0.6mL / g, and particle size range is 3~6mm.

[0006] Preferably, the γ-alumina spheres have a specific surface area of ​​200–330 m². 2 / g, pore volume is 0.33~0.54mL / g, and particle size range is 4.0~5.5mm.

[0007] Preferably, the content of the active component is not less than 0.15 wt% of the carrier weight.

[0008] Preferably, the active component is a combination of two or more of ruthenium, rhodium, palladium, and platinum.

[0009] γ-alumina spheres possess excellent thermal stability, chemical stability, and mechanical strength, exhibiting a highly porous surface structure and an internal channel network. The high specific surface area of ​​the γ-alumina spheres allows for more thorough contact between the active components and oxygen in the catalyst, improving the reaction rate and efficiency. The industrial platinum group metal deoxygenation catalyst provided by this invention exhibits high thermal stability and good low-temperature activity, enabling successful deoxygenation reactions under normal pressure. The deoxygenation effect is even more significant under heated and pressurized conditions, thereby achieving the goal of eliminating trace amounts of oxygen in industrial hydrogen. Furthermore, this catalyst has good wear resistance and a long service life, reducing customer operating costs.

[0010] In a second aspect, the present invention provides a method for preparing an industrial platinum group metal deoxygenation catalyst, specifically comprising the following steps: adding γ-alumina spheres to a platinum group metal salt solution and impregnating and adsorbing them under acidic conditions to obtain a primary catalyst product; performing liquid-phase reduction on the primary catalyst product to obtain a secondary catalyst product; and drying and calcining the secondary catalyst product to obtain an industrial platinum group metal deoxygenation catalyst.

[0011] The industrial platinum group metal deoxidation catalyst provided by this invention is prepared by an equal-volume impregnation method. By utilizing the high specific surface area of ​​granular γ-alumina microspheres, the dispersion of platinum group metal active components on the surface of alumina microspheres is significantly improved. This not only effectively prevents the sintering of active components but also enhances the low-temperature deoxidation catalytic activity of the catalyst.

[0012] Preferably, before the preparation process, the γ-alumina balls are pretreated by washing and soaking with a pretreatment reagent. The pretreatment reagent is selected from one or a mixture of several of deionized water, ethanol, and isopropanol. After washing with the pretreatment reagent, the γ-alumina balls are soaked in the pretreatment reagent for 4 to 8 hours.

[0013] Preferably, the platinum group metal salt solution is selected from one or a mixture of several platinum group metal nitrates and platinum group metal chlorates.

[0014] Preferably, during the impregnation and adsorption process, the acidic conditions are generally adjusted and controlled using a nitric acid solution, so that the pH of the platinum group metal salt solution is 1.5–3.0, and the impregnation and adsorption time is 2–4 hours. The equal-volume impregnation method is simple, economical, easy to operate, and has good controllability. By appropriately adjusting the concentration of the platinum group metal salt and the pH, the active component is uniformly distributed on the support, which can effectively improve the activity of the catalyst. This method is suitable for large-scale production and industrial applications.

[0015] Preferably, the reducing agent used in the liquid-phase reduction is selected from one of hydrogen peroxide solution, hydrazine hydrate solution, and ethylene glycol solution; the concentration of the reducing agent is 10-20 wt%; and the liquid-phase reduction time is generally 2-4 hours. More preferably, the liquid-phase reduction is carried out in 3-5 stages, with each stage lasting 40-60 minutes. By selecting an appropriate reducing agent concentration and the number of reduction stages, platinum group metal atoms deposited on the support are uniformly reduced. Compared to hydrogen reduction, liquid-phase reduction can be carried out at low temperatures, is easier to control and operate, reduces explosion and safety risks, and is more suitable for industrial production.

[0016] Preferably, the intermediate product of the catalyst is dried at 100–200°C for 1–2 hours and then calcined at 400–800°C for 2–4 hours to obtain an industrial platinum group metal deoxidation catalyst. Compared with the prior art, the preparation method provided by the present invention has lower temperatures and shorter times during the drying and baking processes, which significantly reduces production energy consumption and lowers production costs.

[0017] A third aspect of this invention provides the application of industrial platinum group metal deoxygenation catalysts in industrial hydrogen deoxygenation reactions. In alkaline water electrolysis for hydrogen production, the resulting industrial hydrogen contains trace amounts of oxygen, which poses numerous problems for hydrogen applications. For example, in the chemical, metallurgical, and electronics industries, unremoved trace oxygen in hydrogen can easily poison downstream catalysts or products.

[0018] Preferably, the industrial platinum group metal deoxygenation catalyst is used in the deoxygenation reaction of industrial hydrogen with an oxygen content of less than 500 ppm.

[0019] More preferably, the industrial platinum group metal deoxygenation catalyst is applied in the deoxygenation reaction of industrial hydrogen with an oxygen content of 300-500 ppm. Compared with the prior art, the industrial platinum group metal deoxygenation catalyst provided by the present invention has high activity and good sensitivity, and can perform deep deoxygenation of trace oxygen of 300-500 ppm in industrial hydrogen with high deoxygenation precision.

[0020] Specifically, the reaction temperature of the application is not less than 25°C, the pressure is not less than 0.1 MPa, and the space velocity is 1000–20000 h⁻¹. -1 .

[0021] Preferably, the reaction temperature is not less than 60°C, and more preferably 60–100°C.

[0022] Preferably, the reaction pressure is 0.1–0.5 MPa. The deoxygenation reaction can also proceed at a pressure of 0.1 MPa, i.e., at atmospheric pressure.

[0023] Preferably, the reaction space velocity is 1000–12000 h⁻¹. -1 .

[0024] The platinum group metal deoxidation catalyst for industrial use provided by this invention can smoothly carry out deoxidation reactions at low temperature and normal pressure, and still exhibits high-precision deep deoxidation effect on trace amounts of oxygen in industrial hydrogen at high space velocities, deoxidizing industrial hydrogen with an oxygen content of 300-500 ppm to below 1.0 ppm. Compared with existing technologies, this catalyst can perform deep deoxidation on a larger volume of industrial hydrogen per unit time, significantly improving production efficiency and having important significance for industrial production.

[0025] The beneficial effects of this invention are as follows: The industrial platinum group metal deoxidation catalyst provided by this invention uses inexpensive and readily available industrial γ-alumina spheres as a support. The high specific surface area of ​​the γ-alumina spheres improves the deoxidation performance of the catalyst, enabling it to smoothly carry out deoxidation reactions at low temperature and normal pressure, and at space velocities ≥10000 h⁻¹. -1Under ideal conditions, this catalyst still exhibits highly precise deep deoxygenation of trace oxygen (300–500 ppm) in industrial hydrogen, resulting in an outlet oxygen level below 1.0 ppm. Furthermore, the catalyst's preparation process is simple, suitable for large-scale production and industrial applications. The preparation process generates minimal wastewater and waste gas emissions, significantly reduces energy consumption compared to existing technologies, lowers production costs, and aligns with the environmentally friendly concept of clean production. Detailed Implementation

[0026] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. Unless otherwise specified, the methods used in the embodiments of the present invention are conventional methods, and the reagents used are commercially available.

[0027] Example 1:

[0028] 100g of γ-alumina spheres were washed with deionized water and then soaked in deionized water for 8 hours. A platinum group metal salt solution was prepared by dissolving 294mg of chloropalladium acid and 53mg of chloroplatinic acid in 75mL of water. The pH of the mixed solution was adjusted to 1.5 by adding nitric acid. 100g of the pretreated γ-alumina spheres were added, stirred evenly, and allowed to stand for 4 hours for adsorption, yielding the primary catalyst product. Then, the primary catalyst product was added to 75mL of a 12% hydrogen peroxide solution for liquid-phase reduction. The reduction was carried out in four stages, with each stage lasting 45 minutes, yielding the intermediate catalyst product. The intermediate catalyst product was dried at 150℃ for 2 hours and calcined at 550℃ for 2 hours to obtain industrial platinum group metal deoxidation catalyst C-1. The obtained catalyst C-1 contained 0.125% Pd and 0.025% Pt by weight of the support. The specific surface area of ​​the γ-alumina spheres used was 280m². 3 / g, pore volume is 0.45mL / g, and particle size range is 4.0~5.5mm.

[0029] This embodiment also provides the application of the above-prepared industrial platinum group metal deoxidation catalyst C-1 in an industrial hydrogen deoxidation reaction. 18 mL and 12.25 g of the above-mentioned catalyst C-1 were added to a fixed-bed reactor; the feed gas was turned on, the composition of which was 330 ppm O2 and the balance being H2. The deoxidation reaction was carried out at 60°C, atmospheric pressure, and a space velocity of 10000 h⁻¹. -1The test was conducted under the following conditions; the oxygen content of the outlet gas was detected using an online oxygen analyzer, and the oxygen content of the outlet gas was 0.77 ppm.

[0030] Examples 2-4:

[0031] The difference from Example 1 is that Examples 2 to 4 used γ-alumina spheres of different sizes as carriers to prepare industrial platinum group metal deoxygenation catalysts C-2, C-3, and C-4, which were applied to industrial hydrogen deoxygenation reactions under the same conditions. The details are shown in Table 1.

[0032] Comparative Example 1:

[0033] The difference from Example 1 is that Comparative Example 1 uses α-alumina spheres as a support to prepare platinum group metal deoxygenation catalyst A-1, which is applied to industrial hydrogen deoxygenation reaction under the same conditions. The details are shown in Table 1.

[0034] Table 1. Effect of alumina spheres of different sizes on the catalytic effect of the prepared deoxygenation catalyst

[0035]

[0036] As shown in Examples 1-4 and Comparative Example 1, γ-alumina spheres with a larger specific surface area obviously have a larger effective noble metal loading area than α-alumina spheres, increasing the contact surface of the catalytic reaction and significantly improving the catalytic effect of the prepared industrial platinum group metal deoxygenation catalyst. As shown in Examples 1-3, within a certain range, the deoxygenation effect of the prepared catalyst gradually improves with the increase of pore volume and specific surface area of ​​γ-alumina spheres. Among them, the industrial platinum group metal deoxygenation catalyst prepared in Example 1 exhibits the best deoxygenation capacity at low temperature and atmospheric pressure for 10000 h⁻¹. -1 At high air velocities, this invention achieves highly precise deep deoxygenation of feed gas with an oxygen content of 330 ppm, resulting in an outlet oxygen level of 0.77 ppm. This deoxygenation effect is 179 times that of existing technologies, and its high efficiency makes it suitable for rapid deoxygenation of industrial hydrogen. The industrial platinum group metal deoxygenation catalyst provided by this invention can be widely used in petrochemical, pharmaceutical, organic chemical, enameled steel, color steel, packaging and printing, paint spraying, automotive coating, home appliances, plastics and leather, rubber manufacturing, and electronics industries.

[0037] Example 5:

[0038] 100g of γ-alumina spheres were washed with deionized water and then soaked in deionized water for 8 hours. A platinum group metal salt solution was prepared by dissolving 320mg of palladium chloroacid and 29mg of chloroplatinic acid in 75mL of water. The pH of the mixed solution was adjusted to 1.5 by adding nitric acid. 100g of the pretreated γ-alumina spheres were added, stirred evenly, and allowed to stand for 4 hours for adsorption, yielding the primary catalyst product. Then, the primary catalyst product was added to 75mL of a 12% hydrogen peroxide solution for liquid-phase reduction. The reduction was carried out in four stages, with each stage lasting 45 minutes, yielding the intermediate catalyst product. The intermediate catalyst product was dried at 150℃ for 2 hours and calcined at 550℃ for 2 hours to obtain industrial platinum group metal deoxidation catalyst C-5. The obtained catalyst C-5 contained 0.136% Pd and 0.014% Pt by weight of the support. The specific surface area of ​​the γ-alumina spheres used was 280m². 3 / g, pore volume is 0.45mL / g, and particle size range is 4.0~5.5mm.

[0039] This embodiment also provides the application of the above-prepared industrial platinum group metal deoxidation catalyst C-5 in an industrial hydrogen deoxidation reaction. 18 mL and 12.25 g of the above-mentioned catalyst C-5 were packed into a fixed-bed reactor; the feed gas was turned on, the composition of which was 500 ppm O2 and the balance being H2. The deoxidation reaction was carried out at 60°C, atmospheric pressure, and a space velocity of 12000 h⁻¹. -1 The test was conducted under the following conditions; the oxygen content of the outlet gas was detected using an online oxygen analyzer, and the oxygen content of the outlet gas was 4.64 ppm.

[0040] Examples 6-8:

[0041] The difference from Example 1 is that Examples 6-8 prepared industrial platinum group metal deoxygenation catalysts C-6, C-7, and C-8 by using different platinum group metal salts and different feed ratios, and applied them to industrial hydrogen deoxygenation reactions. The details are shown in Table 2.

[0042] Table 2. Effects of different active components on the catalytic performance of the prepared deoxygenation catalyst

[0043]

[0044] As can be seen from Examples 1 and 5-8, increasing the platinum atom content or selecting platinum group metal chloride salts can further enhance the catalytic effect of industrial platinum group metal deoxidation catalysts, at 12000h. -1 Even at the above air velocities, it still exhibits excellent deoxygenation performance and extremely high deoxygenation efficiency. Furthermore, hydrogen peroxide is the preferred reducing agent.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope of the present invention.

Claims

1. The application of industrial platinum group metal deoxygenation catalysts in industrial hydrogen deoxygenation reactions, characterized in that, The industrial platinum group metal deoxidation catalyst comprises an active component and a support; the active component is a platinum group metal, specifically one or more of ruthenium, palladium, and platinum; the content of the active component is 0.15 wt% to 0.4 wt% of the support weight; the support is γ-alumina spheres with a specific surface area of ​​200 to 360 m². 2 / g, pore volume is 0.38~0.45 mL / g, and particle size range is 4~5.5 mm; The oxygen content of the industrial hydrogen is 330~500 ppm; The reaction temperature for this application is 60~100℃, the pressure is 0.1~0.5 MPa, and the space velocity is 1000~20000 h⁻¹. -1 .

2. The application according to claim 1, characterized in that, The industrial platinum group metal deoxidation catalyst is prepared by the following method: γ-alumina spheres were added to a platinum group metal salt solution and impregnated and adsorbed under acidic conditions to obtain the primary catalyst product; The primary catalyst product is subjected to liquid-phase reduction to obtain the intermediate catalyst product. The intermediate product of the catalyst is dried and calcined to obtain an industrial platinum group metal deoxygenation catalyst.

3. The application according to claim 2, characterized in that, The platinum group metal salt solution is selected from one or a mixture of several platinum group metal nitrates and platinum group metal chlorates.

4. The application according to claim 2, characterized in that, The reducing agent used in the liquid-phase reduction is selected from one of hydrogen peroxide solution, hydrazine hydrate solution, and ethylene glycol solution.

5. The application according to claim 1, characterized in that, Airspeed is 1000~12000 h -1 .

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