An integrated preparation process for high-purity oxygen

Abstract

The present invention belongs to the field of gas preparation technology, and specifically relates to an integrated high-purity oxygen preparation process. The process includes reacting an aqueous hydrogen peroxide solution and potassium peroxide under the action of a catalyst to generate oxygen and separate the by-product liquid phase, and the oxygen enters the purification stage through a gas-liquid separator; adding sodium pernitrate and ferric nitrate to the liquid phase to generate oxygen and separate it, and then enter the purification process; using a ZnO / activated carbon composite material and a Pt-based catalyst to remove impurities in the oxygen, and finally further purifying it through a molecular sieve and a drying tower to obtain high-purity oxygen. This process improves reaction efficiency and raw material utilization by optimizing the use of catalysts and adsorbent materials, reduces energy consumption and costs, and ensures the stability of oxygen purity. The entire process is environmentally friendly and efficient, and is suitable for fields with high requirements for oxygen purity.

Description

Technical Field

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

[0002] Oxygen is an indispensable resource in modern industry and healthcare, with widespread applications in metallurgy, chemical engineering, environmental protection, healthcare, and food. In particular, in high-tech industries (such as semiconductor manufacturing), healthcare (such as surgical oxygen supply and emergency equipment), and scientific research (such as high-purity gases for experiments), oxygen purity requirements often reach 99.999% or higher. However, common industrial oxygen production technologies currently face numerous challenges in meeting these high-purity requirements, including complex equipment requirements, high energy consumption, and high costs. Consequently, the need for efficient, economical, and environmentally friendly integrated high-purity oxygen production processes is becoming increasingly urgent.

[0003] Currently, industrial oxygen production technologies primarily include cryogenic separation, adsorption separation, water electrolysis, and chemical reaction. Cryogenic separation is a traditional method for separating oxygen, nitrogen, and other inert gases through the liquefaction and fractional distillation of air. This technology leverages the differences in boiling points between gases to produce oxygen through distillation at low temperatures (typically below -180°C). This method can provide high-purity oxygen for large-scale industrial production, typically reaching 99.999%. However, it requires high-precision cryogenic equipment and distillation towers, resulting in high installation and maintenance costs.

[0004] Adsorption separation separates oxygen and nitrogen from air through the selective adsorption properties of adsorbents. Common technologies include pressure swing adsorption (PSA) and vacuum adsorption (VSA). This method is relatively simple to use with low operating costs and can be applied to small- to medium-scale production. However, it typically only provides oxygen with a purity of 95%-99%. Higher purity requirements require further purification.

[0005] Water electrolysis technology, which splits water into oxygen and hydrogen through an electrochemical reaction, is a very clean way to produce oxygen. While the method is simple, requires no air source, and produces pure products, the electrolysis reaction requires significant amounts of electricity, leading to high production costs.

[0006] Chemical reaction methods generate oxygen through the decomposition of oxidants, such as hydrogen peroxide (H2O2) or other peroxide reactions. This method offers simple equipment and flexible operation, suitable for small- to medium-scale applications. However, its efficiency and stability are limited, requiring a highly efficient catalyst to increase the oxygen generation rate and control the formation of byproducts.

[0007] In summary, existing methods generally suffer from complex equipment, high energy consumption, lengthy processes, and limited purification efficiency. Especially for the production of high-purity (≥99.999%) oxygen, existing technologies struggle to simultaneously meet the requirements of high efficiency, cost-effectiveness, and environmental friendliness. Therefore, there is an urgent need to develop a high-purity oxygen production process that reduces energy consumption, simplifies the process, and achieves both environmental friendliness and high efficiency. Summary of the Invention

[0008] The purpose of the present invention is to provide an integrated process for preparing high-purity oxygen, 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:

[0010] An integrated process for preparing high-purity oxygen comprises the following steps:

[0011] (1) Aqueous hydrogen peroxide solution and potassium peroxide are added to the reactor, and a catalyst and a buffer solution 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. The 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;

[0012] (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;

[0013] (3) The oxygen in step (1) and step (2) is passed into an adsorption tower, and the impurity gas is removed by adsorption using the ZnO / activated carbon composite material;

[0014] (4) The gas after impurity removal in step (3) enters the catalytic reduction device and is further impurity-removed by a Pt-based catalyst;

[0015] (5) The gas after impurity removal 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%.

[0016] 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.

[0017] Furthermore, the catalyst in step (1) is a Cu-doped MnO2-CeO2 catalyst, and the catalyst is added at a rate of 0.01-0.05% by mass of the hydrogen peroxide aqueous solution.

[0018] Furthermore, the preparation method of the Cu-doped MnO2-CeO2 catalyst comprises the following steps:

[0019] (i) manganese nitrate, cerium nitrate, and copper nitrate are mixed in a molar ratio of (2.5-3.5):(1.5-2.5):1 and dissolved in deionized water to prepare a metal salt solution with a concentration of 0.1M to 0.5M. A template Pluronic P123 (polyoxypropylene-polyoxyethylene block copolymer) is added to the metal salt solution to a mass concentration of 2-5% of the template Pluronic P123 in the metal salt solution, and stirred for 20-40 minutes;

[0020] (ii) heating the solution obtained in step (i) to 40-50° C., adding a 10-20% by mass sodium hydroxide aqueous solution while stirring, adjusting the pH to 9-10 to obtain a metal hydroxide precipitate, allowing the precipitate to stand and age for 6-12 hours, removing the precipitate, washing it, and drying it to obtain a precursor powder;

[0021] (iii) calcining the precursor powder at 500-600 °C for 3-5 h to obtain a Cu-doped MnO2-CeO2 catalyst.

[0022] 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 utilizes 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 the redox reaction, 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 the active sites. The fine control of the aging, calcination and other steps ensures the uniform distribution of Cu, Mn and Ce in the oxide lattice, and optimizes the particle size, further improving the catalytic performance.

[0023] Furthermore, the buffer in step (1) is a phosphate buffer with a concentration of 0.1M to 0.5M.

[0024] Furthermore, the mass concentration of the sodium pernitrate aqueous solution in step (2) is 10-20%.

[0025] 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.

[0026] 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 entire process. Sodium pernitrate, as a strong oxidant, decomposes efficiently under the catalytic action of ferric nitrate to release oxygen, while ferric nitrate is oxidized by Fe 3+ and Fe 2+ The redox cycle between the two reactions accelerates oxygen generation and reduces the reaction energy requirement. This process is carried out under mild conditions of 40-50°C, avoiding side reactions. This step cleverly utilizes the liquid byproduct of the first step, converting it into a reaction substrate. This not only improves reaction efficiency but also reduces the burden of waste liquid treatment, demonstrating the advantages of green chemistry.

[0027] Furthermore, the preparation method of the ZnO / activated carbon composite material in step (3) comprises the following steps:

[0028] (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 rinsed with deionized water and dried.

[0029] (b) Dissolve zinc nitrate in deionized water to prepare a 0.1 M to 1.0 M zinc nitrate solution;

[0030] (c) adding the activated carbon dried in step (a) to the zinc nitrate solution, stirring at room temperature for 3-5 hours, and removing the activated carbon;

[0031] (d) The activated carbon obtained in step (c) is placed in an oven and dried at 100-120° C. for 6-8 hours, and then the dried activated carbon is transferred to a muffle furnace for calcination. After calcination, the material is cooled to room temperature to obtain a ZnO / activated carbon composite material.

[0032] Furthermore, the mass ratio of the zinc nitrate to the activated carbon is 0.1-1:1.

[0033] Furthermore, the calcination temperature in step (d) is 450-500° C., and the calcination time is 2-4 hours.

[0034] This invention utilizes a specially formulated ZnO / activated carbon composite material as an adsorption and catalytic material to remove impurity gases such as CO and H2S from oxygen, ensuring the quality of high-purity oxygen. ZnO reacts with H2S to form stable ZnS, which, in the presence of trace amounts of CO, can catalyze its oxidation to CO2. Activated carbon has an extremely high specific surface area and excellent adsorption capacity, physically adsorbing water vapor and other residual impurity molecules from oxygen. This composite material combines the chemical catalysis of ZnO with the physical adsorption properties of activated carbon, enhancing impurity removal efficiency through the uniform distribution of nanoscale ZnO particles.

[0035] 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%.

[0036] The oxygen is further purified in the catalytic reduction device by using a Pt-based catalyst, mainly removing trace amounts of NO x This step further increases the purity of oxygen to 99.999%, meeting the needs of high-end applications.

[0037] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0038] 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 a 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 meticulous design and optimization of the catalyst, including the use of Cu-doped MnO2-CeO2 catalyst and ZnO / activated carbon composite material, further improves 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. This process is simple, with little 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

[0039] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0040] Unless otherwise specified, the raw materials used in the examples are all common commercially available products. The following is an exemplary description:

[0041] Pluronic P123 was purchased from Sigma-Aldrich.

[0042] Activated carbon was purchased from Zhejiang Juhua Co., Ltd. with an average particle size of 3-5 mm.

[0043] Pt / Al2O3 was purchased from Shanghai Cathay Biotechnology Co., Ltd. with a platinum content of 0.5 wt%.

[0044] MnO2-CeO2 catalyst was purchased from Sichuan Jinjiang Chemical Co., Ltd.;

[0045] CuO / activated carbon composites were purchased from Zhejiang Haochen New Materials Co., Ltd.;

[0046] Cu / Al2O3 catalyst was purchased from Jiangsu Suli Chemical Co., Ltd. with a copper content of 5 wt%.

[0047] Example 1

[0048] This embodiment provides a method for preparing a Cu-doped MnO2-CeO2 catalyst, comprising the following steps:

[0049] (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). The template Pluronic P123 was added to the metal salt solution to a concentration of 3% by mass of the template Pluronic P123 in the metal salt solution and stirred for 30 minutes to ensure complete dissolution of the template;

[0050] (ii) heating the solution obtained in step (i) to 45° C., adding a 15% mass concentration of sodium hydroxide aqueous solution with stirring, adjusting the pH to 9, to obtain a metal hydroxide precipitate, and aging the precipitate at 45° C. for 8 hours to further crystallize and stabilize the precipitate, removing the precipitate and washing it with water until the pH of the washing solution is close to neutral, and 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;

[0051] (iii) The dried precursor powder was evenly spread in a high-temperature resistant ceramic crucible with a thickness not exceeding 1 cm. The crucible was placed in a muffle furnace and heated to 550°C at a heating rate of 5°C / min. The crucible was calcined for 4 hours. After the calcination, the crucible was cooled to room temperature in the furnace. The calcined product was taken out and gently ground to obtain a Cu-doped MnO2-CeO2 catalyst.

[0052] Example 2

[0053] This embodiment provides a method for preparing a ZnO / activated carbon composite material, comprising the following steps:

[0054] (a) Activated carbon was soaked in deionized water to ensure that it was completely immersed, and ultrasonicated for 30 minutes to remove surface impurities and dust in the pores. After ultrasonication, the activated carbon was rinsed with deionized water until the washing solution was no longer turbid. After rinsing, the activated carbon was dried at 105°C for 6 hours and set aside.

[0055] (b) Dissolve zinc nitrate in deionized water to prepare a 0.5 M zinc nitrate solution;

[0056] (c) adding the dried activated carbon from step (a) to a zinc nitrate solution at a mass ratio of zinc nitrate to activated carbon of 0.5:1, stirring at room temperature for 4 hours. After stirring, filtering the activated carbon through filter paper to collect the solid portion, and rinsing the surface with deionized water to remove excess zinc nitrate solution;

[0057] (d) The activated carbon from step (c) was placed in an oven and dried at 110°C for 7 hours, and then the dried activated carbon was transferred to a muffle furnace for calcination at a temperature of 480°C for 3 hours. After calcination, the material was cooled to room temperature to obtain a ZnO / activated carbon composite material.

[0058] Example 3

[0059] This embodiment provides an integrated process for preparing high-purity oxygen, comprising the following steps:

[0060] (1) A 40% mass concentration of hydrogen peroxide aqueous solution and potassium peroxide were added to the reactor, and the mass ratio of the hydrogen peroxide aqueous solution to the potassium peroxide was 4:1. Then, the Cu-doped MnO2-CeO2 catalyst prepared in Example 1 was added, and the mass was 0.03% 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 (prepared by disodium hydrogen phosphate and potassium hydrogen phosphate in a molar ratio of 1:1) was added, and the pH of the reaction solution was adjusted to 6. The reaction temperature was raised to 50°C. Oxygen was released during the reaction, 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.

[0061] (2) adding a 15% sodium pernitrate aqueous solution and ferric nitrate 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;

[0062] (3) The oxygen from step (1) and step (2) is passed into an adsorption tower, which is filled with the ZnO / activated carbon composite material prepared in Example 2. The adsorption tower is started, and oxygen flows into the adsorption tower. Impurity gases in the oxygen, such as CO and H2S, are removed by the ZnO / activated carbon composite material.

[0063] (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;

[0064] (5) The gas after impurity removal in step (4) passes through a 5Å molecular sieve device to remove moisture 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%.

[0065] Example 4

[0066] This embodiment provides an integrated process for preparing high-purity oxygen, comprising the following steps:

[0067] (1) A 40% mass concentration of hydrogen peroxide aqueous solution and potassium peroxide were added to the reactor, and the mass ratio of the hydrogen peroxide aqueous solution to potassium peroxide was 5:1. Then, the Cu-doped MnO2-CeO2 catalyst prepared in Example 1 was added, with a mass of 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, and the pH of the reaction solution was adjusted to 6. The reaction temperature was raised to 50°C. Oxygen was released during the reaction, 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.

[0068] (2) adding a 15% mass concentration of sodium pernitrate aqueous solution and ferric nitrate 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;

[0069] (3) The oxygen from step (1) and step (2) is passed into an adsorption tower, which is filled with the ZnO / activated carbon composite material prepared in Example 2. The adsorption tower is started, and oxygen flows into the adsorption tower. Impurity gases in the oxygen, such as CO and H2S, are removed by the ZnO / activated carbon composite material.

[0070] (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 / CeO2 catalyst;

[0071] (5) The gas after impurity removal in step (4) passes through a 5Å molecular sieve device to remove moisture 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%.

[0072] Comparative Example 1

[0073] This comparative example provides an integrated process for preparing high-purity oxygen. The difference from Example 3 is that the Cu-doped MnO2-CeO2 catalyst is prepared as follows:

[0074] (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). A template agent, polyvinyl pyrrolidone (PVP), was added to the metal salt solution to a concentration of 3% by mass of the template agent in the metal salt solution. The mixture was stirred for 30 minutes to ensure complete dissolution of the template agent.

[0075] (ii) heating the solution obtained in step (i) to 45° C., adding a 15% mass concentration of sodium hydroxide aqueous solution with stirring, adjusting the pH to 9, to obtain a metal hydroxide precipitate, and aging the precipitate at 45° C. for 8 hours to further crystallize and stabilize the precipitate, removing the precipitate and washing it with water until the pH of the washing solution is close to neutral, and 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;

[0076] (iii) The dried precursor powder was evenly spread in a high-temperature resistant ceramic crucible with a thickness not exceeding 1 cm. The crucible was placed in a muffle furnace and heated to 500°C at a heating rate of 3°C / min. The crucible was calcined for 4 hours. After the calcination, the crucible was cooled to room temperature in the furnace. The calcined product was taken out and gently ground to obtain a Cu-doped MnO2-CeO2 catalyst.

[0077] This comparative example finally obtained oxygen with a purity of 99.990%.

[0078] Comparative Example 2

[0079] This comparative example provides an integrated process for preparing high-purity oxygen, which differs from Example 3 in that the ZnO / activated carbon composite material is prepared as follows:

[0080] (a) Activated carbon was soaked in deionized water to ensure that it was completely immersed, and ultrasonicated for 30 minutes to remove surface impurities and dust in the pores. After ultrasonication, the activated carbon was rinsed with deionized water until the washing solution was no longer turbid. After rinsing, the activated carbon was dried at 105°C for 6 hours and set aside.

[0081] (b) Dissolve zinc sulfate in deionized water to prepare a 0.5 M zinc sulfate solution;

[0082] (c) adding the activated carbon dried in step (a) to a zinc sulfate solution at a mass ratio of zinc sulfate to activated carbon of 0.5:1, stirring the mixture with a stirrer, and adding 5% ethanol by mass of the zinc sulfate solution to promote adsorption of the zinc salt on the surface of the activated carbon. The mixture was stirred for 1 hour, after which the solution was filtered through filter paper to collect the solid portion, which was then rinsed with deionized water to remove excess zinc sulfate solution. The filtered solid portion was then washed again with ethanol to promote adhesion of the zinc salt and remove surface impurities.

[0083] (d) The activated carbon from step (c) was placed in an oven and dried at 110°C for 7 hours, and then the dried activated carbon was transferred to a muffle furnace for calcination at a temperature of 480°C for 3 hours. After calcination, the material was cooled to room temperature to obtain a ZnO / activated carbon composite material.

[0084] This comparative example finally obtained oxygen with a purity of 99.98%.

[0085] Comparative Example 3

[0086] This comparative example provides an integrated process for preparing high-purity oxygen. The difference from Example 3 is 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.

[0087] Comparative Example 4

[0088] This comparative example provides an integrated process for preparing high-purity oxygen. The difference from Example 3 is 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.

[0089] Comparative Example 5

[0090] This comparative example provides an integrated process for preparing high-purity oxygen. The difference from Example 3 is 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.

[0091] Comparative Example 6

[0092] 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, ultimately obtaining oxygen with a purity of 99.93%.

[0093] The purity of oxygen prepared in the examples and comparative examples is shown in Table 1 below.

[0094] Table 1 Oxygen purity prepared in Examples and Comparative Examples

[0095] 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%

[0096] 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 catalytic activity that is not as good as the Cu-doped MnO2-CeO2 catalyst in Example 3, resulting in reduced 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 incomplete removal of impurities during the separation and generation of oxygen. 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 the presence of certain impurities during 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 incomplete reaction during the reaction process and the generated gas containing more impurities. Comparative Example 4 replaces the ZnO / activated carbon composite material with 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. Comparative Example 5 replaces the Pt / CeO2 catalyst with a commercially available Cu / Al2O3 catalyst. Pt-based catalysts generally have stronger catalytic activity and higher selectivity, especially in removing NO. xThe results were superior to those of Cu / Al2O3 catalysts when removing impurities such as O3 and O3. Commercially available Cu / Al2O3 catalysts may not be suitable for treating certain trace impurities in oxygen purification, resulting in poor removal efficiency. In Comparative Example 6, the excessive concentration of sodium pernitrate and the excessive amount of ferric nitrate added led to increased by-product formation during the reaction. In particular, the excessively high concentration of sodium pernitrate resulted in an overly vigorous reaction, making it impossible to stably control the generation of oxygen.

[0097] 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 within 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 solution 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. The 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; the catalyst is a Cu-doped MnO2-CeO2 catalyst, and the catalyst is added at a rate of 0.01-0.05% by mass of the aqueous hydrogen peroxide solution; (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 passed 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 gas after impurity removal 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%; The preparation method of Cu-doped MnO2-CeO2 catalyst comprises: (i) manganese nitrate, cerium nitrate, and copper nitrate are mixed in a molar ratio of (2.5-3.5):(1.5-2.5):1, dissolved in deionized water to prepare a metal salt solution with a concentration of 0.1 M to 0.5 M, and a template agent Pluronic P123 is added to the metal salt solution. The mass concentration of the template agent Pluronic P123 in the metal salt solution is 2-5%, and the mixture is stirred for 20-40 minutes; (ii) heating the solution obtained in step (i) to 40-50° C., adding a 10-20% by mass sodium hydroxide aqueous solution while stirring, adjusting the pH to 9-10 to obtain a metal hydroxide precipitate, allowing the precipitate to stand and age 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; The preparation method of the ZnO / activated carbon composite material comprises: (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 rinsed with deionized water and dried. (b) Dissolve 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 removing the activated carbon; (d) The activated carbon obtained in step (c) is placed in an oven and dried at 100-120° C. for 6-8 hours, and then the dried activated carbon is transferred to a muffle furnace for calcination. After calcination, the material is cooled to room temperature to obtain a ZnO / activated carbon composite material.

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 buffer solution in step (1) is a phosphate buffer solution with a concentration of 0.1M to 0.5M.

4. 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%.

5. 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.

6. The preparation process according to claim 5, 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.

7. 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%.