Integrated preparation process of high-purity oxygen

Abstract

The invention belongs to the technical field of gas preparation, and particularly relates to an integrated preparation process of high-purity oxygen. The process comprises the following steps: reacting a hydrogen peroxide aqueous solution with potassium peroxide under the action of a catalyst to generate oxygen, separating a byproduct liquid phase, and enabling the oxygen to enter a purification stage through a gas-liquid separator; sodium nitrate and ferric nitrate are added into the liquid phase, oxygen is generated and separated, and then a purification process is carried out; a ZnO / activated carbon composite material and a Pt-based catalyst are used for removing impurities in oxygen, and finally the oxygen is further purified through a molecular sieve and a drying tower to obtain high-purity oxygen. According to the process, by optimizing the use of the catalyst and the adsorption material, the reaction efficiency and the raw material utilization rate are improved, the energy consumption and the cost are reduced, and meanwhile, the stability of oxygen purity is ensured. The whole process is environment-friendly and efficient, and is suitable for the field with high oxygen purity requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of gas preparation, and in particular relates to an integrated preparation process for high-purity oxygen. Background Art

[0002] Oxygen is an indispensable and important resource in modern industry and medical fields, and is widely used in metallurgy, chemical industry, environmental protection, medical, food and other industries. Especially in high-tech industries (such as semiconductor manufacturing), medical fields (such as surgical oxygen supply, emergency equipment) and scientific research fields (such as high-purity gases for experiments), the purity requirements of oxygen are often as high as 99.999% or higher. However, the oxygen preparation technology commonly used in industry still faces many challenges in meeting high-purity requirements, including complex equipment requirements, high energy consumption and high costs. Therefore, the demand for efficient, economical and green integrated high-purity oxygen preparation processes is becoming more urgent.

[0003] At present, the industrial preparation technologies of oxygen mainly include cryogenic separation, adsorption separation, electrolysis of water and chemical reaction. Among them, cryogenic separation is a traditional method of separating oxygen, nitrogen and other inert gases by liquefaction and fractionation of air. The core of this technology is to use the difference in boiling points of different gases to obtain oxygen by distillation under low temperature (usually below -180°C). This aspect can provide high-purity oxygen in large-scale industrial production, and the purity can usually reach 99.999%, but it requires high-precision cryogenic equipment and distillation towers, and the installation and maintenance costs are high.

[0004] Adsorption separation separates oxygen and nitrogen from the air through the selective adsorption characteristics of adsorbents. Common technologies include pressure swing adsorption (PSA) and vacuum adsorption (VSA). This method has relatively simple equipment and low operating costs. It can be used in small and medium-scale production, but it can usually only provide oxygen with a purity of 95%-99%. High-purity requirements require further purification.

[0005] Electrolysis of water is a very clean way to produce oxygen by decomposing water through electrochemical reactions to generate oxygen and hydrogen. This method is simple in technology, does not require an air source, and produces pure products, but the electrolysis reaction requires a lot of electricity and has a high production cost.

[0006] The chemical reaction method uses the decomposition reaction of oxidants to generate oxygen, such as the decomposition of hydrogen peroxide (H2O2) or the reaction of other peroxides. This method has simple equipment and flexible operation, and can meet the needs of small and medium-scale applications, but the reaction efficiency and stability are limited, and an efficient catalyst is required to increase the oxygen generation rate and control the generation of by-products.

[0007] In summary, the existing methods generally have the problems of complex equipment, high energy consumption, lengthy process and limited purification efficiency. Especially in the preparation of high-purity (≥99.999%) oxygen, the existing technology is difficult to meet the requirements of high efficiency, economy and greenness at the same time. Therefore, it is urgent to develop a high-purity oxygen preparation process that can reduce energy consumption, simplify the process, and be both environmentally friendly and efficient. Summary of the invention

[0008] The purpose of the present invention is to provide an integrated high-purity oxygen preparation process, which realizes the continuous production of high-purity oxygen by combining chemical reaction with multi-stage purification.

[0009] In order to achieve the above object, the present invention provides the following technical solutions: A high-purity oxygen integrated preparation process comprises the following steps: (1) Aqueous hydrogen peroxide solution and potassium peroxide are added to the reactor, and a catalyst and a buffer are added at the same time. The pH of the reaction solution is adjusted to 6-7, and the reaction temperature is raised to 45-55°C. Oxygen is released during the reaction, and a liquid by-product phase is generated. Oxygen is separated from the liquid phase and directly enters the subsequent purification stage. The liquid phase is used as a substrate for the next reaction; (2) adding sodium pernitrate aqueous solution and ferric nitrate to the liquid phase of step (1), controlling the reaction temperature to 40-50° C., stirring the reaction, releasing oxygen during the reaction, separating the oxygen from the liquid phase, and entering the subsequent purification stage; (3) The oxygen in step (1) and step (2) is introduced into an adsorption tower, and the impurity gas is removed by adsorption using the ZnO / activated carbon composite material; (4) The gas after impurity removal in step (3) enters the catalytic reduction device and is further impurity-removed by a Pt-based catalyst; (5) The impurity-free gas in step (4) passes through a 5Å molecular sieve device and a drying tower to finally obtain high-purity oxygen with a purity of 99.999%.

[0010] Furthermore, the concentration of the aqueous hydrogen peroxide solution in step (1) is 30-50%, and the mass ratio of the aqueous hydrogen peroxide solution to potassium peroxide is 3-5:1.

[0011] Furthermore, the catalyst in step (1) is a Cu-doped MnO2-CeO2 catalyst, and the catalyst is added at 0.01-0.05% of the mass of the hydrogen peroxide aqueous solution.

[0012] Furthermore, the preparation method of the Cu-doped MnO2-CeO2 catalyst comprises the following steps: (i) mixing manganese nitrate, cerium nitrate and copper nitrate in a molar ratio of (2.5-3.5):(1.5-2.5):1, dissolving in deionized water to prepare a metal salt solution with a concentration of 0.1M to 0.5M, adding a template Pluronic P123 (polyoxypropylene-polyoxyethylene block copolymer) to the metal salt solution, wherein the mass concentration of the template Pluronic P123 in the metal salt solution is 2-5%, and stirring for 20-40 minutes; (ii) heating the solution obtained in step (i) to 40-50° C., adding a 10-20% sodium hydroxide aqueous solution under stirring, adjusting the pH to 9-10 to obtain a metal hydroxide precipitate, allowing the precipitate to stand for aging for 6-12 hours, removing the precipitate, washing it, and drying it to obtain a precursor powder; (iii) calcining the precursor powder at 500-600 °C for 3-5 hours to obtain a Cu-doped MnO2-CeO2 catalyst.

[0013] The Cu-doped MnO2-CeO2 catalyst significantly improves the decomposition efficiency of hydrogen peroxide and potassium peroxide through synergistic catalysis, ensuring the stability and efficiency of oxygen generation. The catalyst uses the variable valence characteristics of MnO2 and CeO2 to form an efficient redox cycle. 3+ / Mn 4+ and Ce 3+ / Ce 4+ The electron transfer between them effectively promotes the generation of active oxygen species. At the same time, Cu doping introduces oxygen vacancies, improves the activity of redox reactions, and enhances the stability of the catalyst. By using Pluronic P123 as a soft template, a regular pore structure is formed during the preparation process, which greatly increases the specific surface area and thus improves the exposure rate of active sites. Fine control of steps such as aging and calcination ensures the uniform distribution of Cu, Mn and Ce in the oxide lattice, optimizes the particle size, and further improves the catalytic performance.

[0014] Furthermore, the buffer in step (1) is a phosphate buffer with a concentration of 0.1M to 0.5M.

[0015] Furthermore, the mass concentration of the sodium pernitrate aqueous solution in step (2) is 10-20%.

[0016] Furthermore, in step (2), based on the volume of the liquid phase, 100-200 g of sodium pernitrate aqueous solution and 0.1-0.5 g of ferric nitrate are added per liter of liquid phase.

[0017] Step (2) adds sodium pernitrate and ferric nitrate to the liquid phase of the first step reaction, further generates oxygen through redox reaction, and reuses the residual reactants in the liquid phase, thereby improving the raw material utilization rate and oxygen production of the overall process. Sodium pernitrate, as a strong oxidant, is efficiently decomposed under the catalytic action of ferric nitrate to release oxygen, while ferric nitrate is catalyzed by Fe 3+ and Fe 2+ The redox cycle between the two accelerates the generation of oxygen and reduces the energy requirement of the reaction. This process is carried out under mild conditions of 40-50°C, avoiding the occurrence of side reactions. This step cleverly utilizes the liquid byproduct of the first step and converts it into a reaction substrate, which not only improves the reaction efficiency but also reduces the burden of waste liquid treatment, demonstrating the advantages of green chemistry.

[0018] Furthermore, the preparation method of the ZnO / activated carbon composite material in step (3) comprises the following steps: (a) Soaking the activated carbon in deionized water and ultrasonically treating it for 20-40 minutes to remove surface impurities and dust in the pores. After the ultrasonic treatment, the activated carbon is washed with deionized water and dried; (b) dissolving zinc nitrate in deionized water to prepare a 0.1 M to 1.0 M zinc nitrate solution; (c) adding the activated carbon dried in step (a) to the zinc nitrate solution, stirring at room temperature for 3-5 hours, and taking out the activated carbon; (d) placing the activated carbon from step (c) in an oven and drying it at 100-120° C. for 6-8 hours, then transferring the dried activated carbon to a muffle furnace for calcination, and after calcination, cooling the material to room temperature to obtain a ZnO / activated carbon composite material.

[0019] Furthermore, the mass ratio of the zinc nitrate to the activated carbon is 0.1-1:1.

[0020] Furthermore, the calcination temperature in step (d) is 450-500° C. and the calcination time is 2-4 hours.

[0021] The present invention uses a specially prepared ZnO / activated carbon composite material as an adsorption and catalytic material to remove impurity gases such as CO and H2S in oxygen to ensure the quality of high-purity oxygen. ZnO reacts with H2S to generate stable ZnS, and at the same time, in the presence of trace amounts of CO, it can catalyze its oxidation to CO2. Activated carbon has an extremely high specific surface area and excellent adsorption capacity, and can physically adsorb water vapor and other residual impurity molecules in oxygen. The composite material combines the chemical catalysis of ZnO and the physical adsorption characteristics of activated carbon, and enhances the removal efficiency of impurities through uniformly distributed nano-scale ZnO particles.

[0022] Furthermore, the Pt-based catalyst in step (4) is one of Pt / Al2O3, Pt / CeO2, Pt / TiO2, Pt / SiO2, and Pt / ZrO2, and the Pt loading amount is 0.5%-2.0%.

[0023] The oxygen is further purified in the catalytic reduction device by using a Pt-based catalyst, mainly removing trace amounts of NO x , O3 and other impurity gases that are difficult to remove by physical or chemical adsorption. This step further increases the purity of oxygen to 99.999%, meeting the needs of high-end applications.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are: The present invention proposes an integrated preparation process for high-purity oxygen, which has the significant advantages of high efficiency, environmental protection and economy. Through the two-stage oxygen generation reaction, the decomposition reaction of hydrogen peroxide and potassium peroxide and the redox reaction of sodium pernitrate are fully utilized to maximize the oxygen generation efficiency and raw material utilization rate. At the same time, the reaction conditions are mild, avoiding the need for high-energy consumption equipment. The detailed design and optimization of the catalyst, including the use of Cu-doped MnO2-CeO2 catalyst and ZnO / activated carbon composite material, further improve the efficiency of oxygen generation and impurity removal, ensuring the high stability and long-term operation capability of the system. In addition, combined with the deep purification of Pt-based catalysts and the precise separation of 5Å molecular sieves, the present invention successfully prepares high-purity oxygen with a purity of 99.999%, meeting the needs of high-end fields such as industry, medical care and laboratories. The process is simple, with less waste, in line with the concept of green chemical industry, and has broad application prospects and important promotion value in the field of oxygen preparation. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Unless otherwise specified, the raw materials used in the examples are all common commercially available products. The following is an exemplary description: Pluronic P123 was purchased from Sigma-Aldrich.

[0027] Activated carbon was purchased from Zhejiang Juhua Co., Ltd. with an average particle size of 3-5 mm.

[0028] Pt / Al2O3 was purchased from Shanghai Cathay Biotechnology Co., Ltd. with a platinum content of 0.5 wt%.

[0029] MnO2-CeO2 catalyst was purchased from Sichuan Jinjiang Chemical Co., Ltd.; CuO / activated carbon composites were purchased from Zhejiang Haochen New Materials Co., Ltd.; The Cu / Al2O3 catalyst was purchased from Jiangsu Suli Chemical Co., Ltd. with a copper content of 5 wt%.

[0030] Example 1

[0031] This embodiment provides a method for preparing a Cu-doped MnO2-CeO2 catalyst, comprising the following steps: (i) manganese nitrate, cerium nitrate and copper nitrate were mixed in a molar ratio of 3:2:1 and dissolved in deionized water to prepare a metal salt solution with a total concentration of 0.3 M of the three (manganese nitrate, cerium nitrate and copper nitrate), and a template Pluronic P123 was added to the metal salt solution. The mass concentration of the template Pluronic P123 in the metal salt solution was 3%, and the mixture was stirred for 30 minutes to ensure that the template was completely dissolved; (ii) heating the solution obtained in step (i) to 45° C., adding a 15% mass concentration of sodium hydroxide aqueous solution under stirring, adjusting the pH to 9, obtaining a metal hydroxide precipitate, allowing the precipitate to stand and age at 45° C. for 8 hours to further crystallize and stabilize the precipitate, taking out the precipitate and washing it with water until the pH of the washing liquid is close to neutral, placing the washed precipitate in a vacuum drying oven, and drying it at 80° C. for 10 hours to obtain a light green precursor powder; (iii) The dried precursor powder is evenly spread in a high-temperature resistant ceramic crucible with a thickness not exceeding 1 cm. The crucible is placed in a muffle furnace and heated to 550°C at a heating rate of 5°C / min. The crucible is calcined for 4 hours. After the calcination, the crucible is cooled to room temperature with the furnace. The calcined product is taken out and gently ground to obtain a Cu-doped MnO2-CeO2 catalyst.

[0032] Example 2

[0033] This embodiment provides a method for preparing a ZnO / activated carbon composite material, comprising the following steps: (a) Soak the activated carbon in deionized water to ensure that the activated carbon is completely immersed, and perform ultrasonic treatment for 30 minutes to remove surface impurities and dust in the pores. After the ultrasonic treatment, wash the activated carbon with deionized water until the washing liquid has no obvious turbidity. After the washing is completed, dry it at 105°C for 6 hours for use; (b) dissolving zinc nitrate in deionized water to prepare a 0.5 M zinc nitrate solution; (c) adding the activated carbon dried in step (a) to a zinc nitrate solution, wherein the mass ratio of zinc nitrate to activated carbon is 0.5:1, and stirring at room temperature for 4 hours. After stirring, filtering the activated carbon through filter paper, collecting the solid part, and rinsing the surface with deionized water to remove excess zinc nitrate solution; (d) placing the activated carbon from step (c) in an oven and drying it at 110°C for 7 hours, then transferring the dried activated carbon to a muffle furnace for calcination at a temperature of 480°C for 3 hours. After calcination, the material is cooled to room temperature to obtain a ZnO / activated carbon composite material.

[0034] Example 3

[0035] This embodiment provides a high-purity oxygen integrated preparation process, comprising the following steps: (1) adding a 40% mass concentration of hydrogen peroxide aqueous solution and potassium peroxide to a reactor, wherein the mass ratio of the hydrogen peroxide aqueous solution to the potassium peroxide is 4:1, and then adding the Cu-doped MnO2-CeO2 catalyst prepared in Example 1, wherein the mass is 0.03% of the mass of the hydrogen peroxide aqueous solution, to catalyze the decomposition reaction of hydrogen peroxide, adding a 0.3 M concentration of phosphate buffer (formed by disodium hydrogen phosphate and potassium hydrogen phosphate in a molar ratio of 1:1), adjusting the pH of the reaction solution to 6, and raising the reaction temperature to 50° C. During the reaction, oxygen is released and a by-product liquid phase is generated. The oxygen is separated from the liquid phase by a gas-liquid separator and directly enters a subsequent purification stage. The liquid phase is used as a substrate for the next reaction; (2) adding sodium pernitrate aqueous solution and ferric nitrate with a mass concentration of 15% to the liquid phase of step (1), adding 150 g of sodium pernitrate aqueous solution and 0.3 g of ferric nitrate per liter of liquid phase based on the volume of the liquid phase, controlling the reaction temperature to 45° C., stirring the reaction, releasing oxygen during the reaction, separating the oxygen from the liquid phase through a gas-liquid separator, and entering the subsequent purification stage; (3) The oxygen in step (1) and step (2) is introduced into an adsorption tower, the ZnO / activated carbon composite material prepared in Example 2 is filled in the adsorption tower, the adsorption tower is started, oxygen flows into the adsorption tower, and impurity gases such as CO and H2S in the oxygen are removed by the ZnO / activated carbon composite material; (4) The gas after impurity removal in step (3) enters the catalytic reduction device, the reaction temperature is set to 120°C, the reaction time is set to 30 minutes, and the impurities are further removed by the Pt / Al2O3 catalyst loaded in the catalytic reduction device; (5) The gas after impurity removal in step (4) passes through a 5Å molecular sieve device to remove moisture by adsorption at room temperature. Finally, the oxygen enters a drying tower to further remove trace moisture and other impurities, ultimately obtaining high-purity oxygen with a purity of 99.999%.

[0036] Example 4

[0037] This embodiment provides a high-purity oxygen integrated preparation process, comprising the following steps: (1) A 40% mass concentration of hydrogen peroxide aqueous solution and potassium peroxide were added to a reactor, the mass ratio of the hydrogen peroxide aqueous solution to the potassium peroxide being 5:1, and then the Cu-doped MnO2-CeO2 catalyst prepared in Example 1 was added, the mass of which was 0.02% of the mass of the hydrogen peroxide aqueous solution to catalyze the decomposition reaction of hydrogen peroxide, a 0.3 M concentration of phosphate buffer was added, the pH of the reaction solution was adjusted to 6, and the reaction temperature was raised to 50° C. During the reaction, oxygen was released and a by-product liquid phase was generated. The oxygen was separated from the liquid phase by a gas-liquid separator and directly entered the subsequent purification stage. The liquid phase was used as a substrate for the next reaction; (2) adding sodium pernitrate aqueous solution and ferric nitrate with a mass concentration of 15% to the liquid phase of step (1), adding 120 g of sodium pernitrate aqueous solution and 0.4 g of ferric nitrate per liter of liquid phase based on the volume of the liquid phase, controlling the reaction temperature to 45° C., stirring the reaction, releasing oxygen during the reaction, separating the oxygen from the liquid phase through a gas-liquid separator, and entering the subsequent purification stage; (3) The oxygen in step (1) and step (2) is introduced into an adsorption tower, the ZnO / activated carbon composite material prepared in Example 2 is filled in the adsorption tower, the adsorption tower is started, oxygen flows into the adsorption tower, and impurity gases such as CO and H2S in the oxygen are removed by the ZnO / activated carbon composite material; (4) The gas after impurity removal in step (3) enters the catalytic reduction device, the reaction temperature is set to 120°C, the reaction time is set to 30 minutes, and impurities are further removed by Pt / CeO2 catalyst; (5) The gas after impurity removal in step (4) passes through a 5Å molecular sieve device to remove moisture by adsorption at room temperature. Finally, the oxygen enters a drying tower to further remove trace moisture and other impurities, ultimately obtaining high-purity oxygen with a purity of 99.999%.

[0038] Comparative Example 1 This comparative example provides an integrated preparation process for high-purity oxygen, which is different from Example 3 in that the Cu-doped MnO2-CeO2 catalyst is prepared as follows: (i) manganese nitrate, cerium nitrate and copper nitrate were mixed in a molar ratio of 1:1:1 and dissolved in deionized water to prepare a metal salt solution with a total concentration of 0.3 M of the three (manganese nitrate, cerium nitrate and copper nitrate), and a template agent PVP (polyvinyl pyrrolidone) was added to the metal salt solution. The mass concentration of the template agent PVP in the metal salt solution was 3%, and the mixture was stirred for 30 minutes to ensure that the template agent was completely dissolved; (ii) heating the solution obtained in step (i) to 45° C., adding a 15% mass concentration of sodium hydroxide aqueous solution under stirring, adjusting the pH to 9, obtaining a metal hydroxide precipitate, allowing the precipitate to stand and age at 45° C. for 8 hours to further crystallize and stabilize the precipitate, taking out the precipitate and washing it with water until the pH of the washing liquid is close to neutral, placing the washed precipitate in a vacuum drying oven, and drying it at 80° C. for 10 hours to obtain a light green precursor powder; (iii) The dried precursor powder is evenly spread in a high-temperature resistant ceramic crucible with a thickness not exceeding 1 cm. The crucible is placed in a muffle furnace and heated to 500°C at a heating rate of 3°C / min. The crucible is calcined for 4 hours. After the calcination, the crucible is cooled to room temperature with the furnace. The calcined product is taken out and gently ground to obtain a Cu-doped MnO2-CeO2 catalyst.

[0039] This comparative example finally obtained oxygen with a purity of 99.990%.

[0040] Comparative Example 2 This comparative example provides an integrated preparation process for high-purity oxygen, which differs from Example 3 in that the ZnO / activated carbon composite material is prepared as follows: (a) Soak the activated carbon in deionized water to ensure that the activated carbon is completely immersed, and perform ultrasonic treatment for 30 minutes to remove surface impurities and dust in the pores. After the ultrasonic treatment, wash the activated carbon with deionized water until the washing liquid has no obvious turbidity. After the washing is completed, dry it at 105°C for 6 hours for use; (b) dissolving zinc sulfate in deionized water to prepare a 0.5 M zinc sulfate solution; (c) adding the activated carbon dried in step (a) to a zinc sulfate solution, wherein the mass ratio of zinc sulfate to activated carbon is 0.5:1, stirring with a stirrer, and adding ethanol in an amount of 5% by mass of the zinc sulfate solution to promote the adsorption of zinc salt on the surface of the activated carbon, stirring for 1 hour, after which the solution is filtered through filter paper, the solid portion is collected, and rinsed with deionized water to remove excess zinc sulfate solution, and the filtered solid is washed again with ethanol to promote the adhesion of zinc salt and remove surface impurities; (d) placing the activated carbon from step (c) in an oven and drying it at 110°C for 7 hours, then transferring the dried activated carbon to a muffle furnace for calcination at a temperature of 480°C for 3 hours. After calcination, the material is cooled to room temperature to obtain a ZnO / activated carbon composite material.

[0041] This comparative example finally obtained oxygen with a purity of 99.98%.

[0042] Comparative Example 3 This comparative example provides an integrated process for preparing high-purity oxygen, which differs from Example 3 in that the Cu-doped MnO2-CeO2 catalyst is replaced with a commercially available MnO2-CeO2 catalyst (Sichuan Jinjiang Chemical Co., Ltd.), and finally oxygen with a purity of 99.98% is obtained.

[0043] Comparative Example 4 This comparative example provides an integrated preparation process for high-purity oxygen, which differs from Example 3 in that the ZnO / activated carbon composite material is replaced with a commercially available CuO / activated carbon composite material (Zhejiang Haochen New Materials Co., Ltd.), and finally oxygen with a purity of 99.95% is obtained.

[0044] Comparative Example 5 This comparative example provides an integrated preparation process for high-purity oxygen, which differs from Example 3 in that the Pt / CeO2 catalyst is replaced with a commercially available Cu / Al2O3 catalyst (Jiangsu Suli Chemical Co., Ltd.), and finally oxygen with a purity of 99.90% is obtained.

[0045] Comparative Example 6 This comparative example provides an integrated process for preparing high-purity oxygen, which differs from Example 3 in that the concentration of the sodium pernitrate aqueous solution in step (2) is 25%, and 1 g of ferric nitrate is added per liter of liquid phase based on the volume of the liquid phase, and finally oxygen with a purity of 99.93% is obtained.

[0046] The purity of oxygen prepared in the examples and comparative examples is shown in Table 1 below.

[0047] Table 1 Oxygen purity prepared in Examples and Comparative Examples Group Oxygen purity Example 3 99.999% Example 4 99.999% Comparative Example 1 99.990% Comparative Example 2 99.98% Comparative Example 3 99.98% Comparative Example 4 99.95% Comparative Example 5 99.90% Comparative Example 6 99.93% It can be seen from the above results that the integrated preparation process provided by the present invention can obtain high-purity oxygen with a purity of up to 99.999%. Comparative Example 1 changes the composition and template of the Cu-doped MnO2-CeO2 catalyst. The different metal ratios result in a catalytic activity that is not as good as the Cu-doped MnO2-CeO2 catalyst in Example 3, resulting in a decrease in reaction efficiency and an oxygen generation rate that is not as expected; the introduction of the PVP template may change the microstructure and specific surface area of ​​the catalyst, thereby affecting the efficiency of the catalytic reaction, resulting in the separation and generation of oxygen. Impurities are not completely removed. The ZnO / activated carbon composite material prepared in Comparative Example 2 may be due to uneven distribution of zinc or pore structure limitations of the composite material, resulting in certain impurities in the adsorption and separation process. Comparative Example 3 replaces the Cu-doped MnO2-CeO2 catalyst with a commercially available MnO2-CeO2 catalyst, resulting in a decrease in catalytic activity and selectivity, and the reaction efficiency is not as good as the homemade Cu-doped catalyst. In addition, the purity, particle size and distribution of the commercially available catalyst may not be as uniform as the catalyst prepared in the laboratory, resulting in an incomplete reaction during the reaction, and the generated gas contains more impurities. In Comparative Example 4, the ZnO / activated carbon composite material is replaced by a commercially available CuO / activated carbon composite material. The commercially available CuO / activated carbon composite material has low surface activity, relatively poor adsorption capacity and selectivity, and is not as effective as the homemade ZnO / activated carbon composite material in removing impurity gases (such as CO and H2S), resulting in more residual impurities in oxygen. In Comparative Example 5, the Pt / CeO2 catalyst is replaced by a commercially available Cu / Al2O3 catalyst. Pt-based catalysts generally have stronger catalytic activity and higher selectivity, especially in removing NO x The effect is better than that of Cu / Al2O3 catalyst when removing impurities such as and O3. The commercially available Cu / Al2O3 catalyst may not be suitable for treating some specific trace impurities in oxygen purification, resulting in poor removal effect. In Comparative Example 6, the excessive concentration of sodium pernitrate and the excessive amount of ferric nitrate added led to increased generation of by-products during the reaction, especially the excessively high concentration of sodium pernitrate caused the reaction to be too violent, and the generation of oxygen could not be stably controlled.

[0048] The above is a preferred embodiment 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 present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A high-purity oxygen integrated preparation process, comprising the following steps: (1) Aqueous hydrogen peroxide solution and potassium peroxide are added to the reactor, and a catalyst and a buffer are added at the same time. The pH of the reaction solution is adjusted to 6-7, and the reaction temperature is raised to 45-55°C. Oxygen is released during the reaction, and a by-product liquid phase is generated. Oxygen is separated from the liquid phase and directly enters the subsequent purification stage. The liquid phase is used as a substrate for the next reaction; (2) adding sodium pernitrate aqueous solution and ferric nitrate to the liquid phase of step (1), controlling the reaction temperature to 40-50° C., stirring the reaction, releasing oxygen during the reaction, separating the oxygen from the liquid phase, and entering the subsequent purification stage; (3) The oxygen in step (1) and step (2) is introduced into an adsorption tower, and the impurity gas is removed by adsorption using the ZnO / activated carbon composite material; (4) The gas after impurity removal in step (3) enters the catalytic reduction device and is further impurity-removed by a Pt-based catalyst; (5) The impurity-free gas in step (4) passes through a 5Å molecular sieve device and a drying tower to finally obtain high-purity oxygen with a purity of 99.999%.

2. The preparation process according to claim 1, characterized in that: The concentration of the aqueous hydrogen peroxide solution in step (1) is 30-50%, and the mass ratio of the aqueous hydrogen peroxide solution to potassium peroxide is 3-5:

1.

3. The preparation process according to claim 1, characterized in that: The catalyst in step (1) is a Cu-doped MnO2-CeO2 catalyst, and the catalyst is added at 0.01-0.05% of the mass of the hydrogen peroxide aqueous solution.

4. The preparation process according to claim 3, characterized in that: The preparation method of the Cu-doped MnO2-CeO2 catalyst comprises the following steps: (i) mixing manganese nitrate, cerium nitrate and copper nitrate in a molar ratio of (2.5-3.5):(1.5-2.5):1, dissolving in deionized water to prepare a metal salt solution with a concentration of 0.1M to 0.5M, adding a template Pluronic P123 to the metal salt solution, wherein the mass concentration of the template Pluronic P123 in the metal salt solution is 2-5%, and stirring for 20-40 minutes; (ii) heating the solution obtained in step (i) to 40-50° C., adding a 10-20% sodium hydroxide aqueous solution under stirring, adjusting the pH to 9-10 to obtain a metal hydroxide precipitate, allowing the precipitate to stand for aging for 6-12 hours, removing the precipitate, washing it, and drying it to obtain a precursor powder; (iii) calcining the precursor powder at 500-600 °C for 3-5 hours to obtain a Cu-doped MnO2-CeO2 catalyst.

5. The preparation process according to claim 1, characterized in that: The buffer in step (1) is a phosphate buffer with a concentration of 0.1M to 0.5M.

6. The preparation process according to claim 1, characterized in that: The mass concentration of the sodium pernitrate aqueous solution in step (2) is 10-20%.

7. The preparation process according to claim 1, characterized in that: In step (2), based on the volume of the liquid phase, 100-200 g of sodium pernitrate aqueous solution and 0.1-0.5 g of ferric nitrate are added per liter of liquid phase.

8. The preparation process according to claim 1, characterized in that: The method for preparing the ZnO / activated carbon composite material in step (3) comprises the following steps: (a) Soaking the activated carbon in deionized water and ultrasonically treating it for 20-40 minutes to remove surface impurities and dust in the pores. After the ultrasonic treatment, the activated carbon is washed with deionized water and dried; (b) dissolving zinc nitrate in deionized water to prepare a 0.1 M to 1.0 M zinc nitrate solution; (c) adding the activated carbon dried in step (a) to the zinc nitrate solution, stirring at room temperature for 3-5 hours, and taking out the activated carbon; (d) placing the activated carbon from step (c) in an oven and drying it at 100-120° C. for 6-8 hours, then transferring the dried activated carbon to a muffle furnace for calcination, and after calcination, cooling the material to room temperature to obtain a ZnO / activated carbon composite material.

9. The preparation process according to claim 8, characterized in that: The mass ratio of the zinc nitrate to the activated carbon is 0.1-1:1, the calcination temperature in step (d) is 450-500° C., and the calcination time is 2-4 hours.

10. The preparation process according to claim 1, characterized in that: The Pt-based catalyst in step (4) is one of Pt / Al2O3, Pt / CeO2, Pt / TiO2, Pt / SiO2, and Pt / ZrO2, and the Pt loading amount is 0.5%-2.0%.