Preparation method for sodium chloride assisted synthesis of oxygen-vacancy-rich perovskite oxygen carrier and application of oxygen-vacancy-rich perovskite oxygen carrier
The method for preparing oxygen-vacancy-enriched perovskite oxygen carriers by using sodium chloride as an aid solves the problems of long preparation cycles, cumbersome steps, and poor safety in existing technologies, and achieves efficient and environmentally friendly oxygen vacancy enhancement and catalytic performance improvement.
Patent Information
- Application Number
- CN202511007394.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2025-11-07
AI Technical Summary
Existing methods for preparing perovskite oxygen carriers suffer from problems such as long cycles, cumbersome steps, and the generation of wastewater and flammable and explosive hydrogen, making it difficult to safely and efficiently increase oxygen vacancy concentrations.
A method for preparing oxygen-rich vacancy perovskite oxygen carriers using sodium chloride-assisted synthesis involves mixing lanthanide, iron-based, and nickel-based compounds with sodium chloride and calcining them in a tube furnace. This method avoids hydrogen thermal reduction during the preparation process and utilizes the fact that sodium chloride is easily removed by water washing during vacancy generation, simplifying the operation and increasing the oxygen vacancy concentration.
This study simplifies the preparation process of perovskite oxygen carriers, increases oxygen vacancy concentration, reduces preparation costs and safety risks, and enhances the catalytic and environmental performance of the oxygen carriers.
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Figure CN120900644A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the field of synthetic gas preparation, in particular to a preparation method of sodium chloride-assisted synthesis of oxygen-rich vacancy perovskite oxygen carrier and application. BACKGROUND
[0002] Synthetic gas mainly composed of CO and H2 can be converted into methanol, ethanol, dimethyl ether, acetic acid, olefins, aromatic hydrocarbons, gasoline, diesel and other chemicals and fuels, and plays an important role in the chemical industry. On the other hand, China is relatively rich in methane resources, which exist in large quantities in natural gas, shale gas, combustible ice, biogas and coal bed methane resources. However, the current utilization of methane is still mainly through combustion. Therefore, the conversion of methane into synthetic gas can effectively expand the high-value utilization path of methane.
[0003] Methane chemical chain synthetic gas uses the lattice oxygen in the solid oxygen carrier to react with methane to produce synthetic gas, which can avoid the explosion risk caused by the mixing of methane and oxygen or air, and also can reduce the excessive oxidation of methane to improve the selectivity of synthetic gas; the H2 / CO ratio is close to 2:1, so there is no need to adjust the H2 / CO ratio through additional processes, which reduces the equipment cost and energy consumption; pure oxygen is not used, so air separation technology is not involved; when H2O, CO2 or H2O-CO2 is used for oxidation regeneration of the oxygen carrier, high-purity H2, CO or synthetic gas can also be prepared. Therefore, methane chemical chain synthetic gas has attracted more and more attention.
[0004] In the technology of methane chemical chain synthetic gas, the oxygen carrier not only activates methane, but also provides an oxygen source for the selective oxidation of methane to produce synthetic gas, and is one of the keys to the technology of methane chemical chain synthetic gas. Perovskite oxygen carriers have been widely studied due to their good oxygen transport capacity and structural stability. At present, the preparation methods of perovskite oxides mainly include co-precipitation, sol-gel, hydrothermal synthesis and the like. However, these methods have problems such as long preparation period, complicated steps and easy generation of wastewater. In addition, in order to improve the migration and diffusion capacity of the lattice oxygen of perovskite oxides, a certain concentration of oxygen vacancies is also required. At present, the treatment method of hydrogen hot reduction can produce oxygen vacancies in perovskite oxides, but this method has problems such as flammability and explosiveness of hydrogen, so it is necessary to seek other methods to safely and efficiently improve the oxygen vacancies of perovskite oxygen carriers. SUMMARY
[0005] The application aims to solve the above problems, and provides a preparation method of sodium chloride-assisted synthesis of oxygen-rich vacancy perovskite oxygen carrier and application, which is simple to operate and can effectively improve the performance of the oxygen carrier.
[0006] In order to achieve the above-mentioned purpose, the technical scheme of the application is as follows: A preparation method of sodium chloride-assisted synthesis of oxygen-rich vacancy perovskite oxygen carrier, comprising the following steps: S1, mix lanthanum compounds, iron compounds, nickel compounds to obtain a preliminary raw material; S2, add sodium chloride to the preliminary raw material to obtain a preliminary mixture; S3, grind the preliminary mixture, and after grinding, place it in a tube furnace, heat the tube furnace from room temperature to 800-850 DEG C under air atmosphere, and calcine for 3-4 hours to obtain an intermediate product; S4, after natural cooling of the intermediate product, remove the contained sodium chloride by water washing operation to prepare an oxygen vacancy rich perovskite oxygen carrier.
[0007] Further, in step S1, the molar ratio of iron and nickel in the composition of lanthanum compounds, iron compounds and nickel compounds is the same as the molar ratio of lanthanum.
[0008] Further, in step S1, the lanthanum compound is lanthanum nitrate, the iron compound is iron nitrate, and the nickel compound is nickel nitrate.
[0009] Further, in step S2, the mass ratio of the sum of the mass of lanthanum compounds, iron compounds and nickel compounds to the mass of sodium chloride is 1:1-3.
[0010] Further, in step S3, when the tube furnace is heated from room temperature to 800-850 DEG C, the heating rate is 5-10 DEG C per minute.
[0011] Further, in step S4, the water washing of the naturally cooled intermediate product is 5 times.
[0012] An application of an oxygen vacancy rich perovskite oxygen carrier, which can be used in the preparation step of preparing synthesis gas by chemical chain methane.
[0013] An application of sodium chloride in the synthesis of an oxygen vacancy rich perovskite oxygen carrier, which can be used in the synthesis step of the oxygen vacancy rich perovskite oxygen carrier.
[0014] Compared with the prior art, the present application has the advantages and positive effects that: 1. The perovskite oxygen carrier in the present application has a short preparation period, simple preparation steps, easy operation, and high preparation efficiency; 2. The present application uses solid phase grinding method to process the raw material, which can avoid the generation of waste liquid, reduce the preparation cost, and improve the environmental performance; 3. The present application uses sodium chloride to improve the oxygen vacancy of the perovskite oxygen carrier, which has low cost and is easy to obtain, and has good water solubility, so that it is easy to remove and recover after reaction, further improving the preparation and production effect of the perovskite oxygen carrier; 4. In the process of preparing the perovskite oxygen carrier with sodium chloride-assisted calcination, oxygen vacancies are generated in situ, eliminating the need for hydrogen thermal reduction. This avoids problems such as the flammability and explosion of hydrogen during the preparation process, effectively improving the safety of the oxygen vacancy generation process and further enhancing the preparation effect of the perovskite oxygen carrier. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 This is the fabrication logic diagram of the present invention; Figure 2 LaFe 0.6 Ni 0.4 O3-3NaCl oxygen carrier and LaFe 0.6 Ni 0.4 XRD pattern of O3 oxygen carrier; Figure 3 LaFe 0.6 Ni 0.4 O3-3NaCl oxygen carrier and LaFe 0.6 Ni 0.4 EPR diagram of O3 oxygen carrier; Figure 4 LaFe 0.6 Ni 0.4 O3-3NaCl oxygen carrier and LaFe 0.6 Ni 0.4 Performance diagram of methane chemical chaining to syngas using O3 oxygen carrier; Figure 5 LaFe 0.5 Ni 0.5 O3-3NaCl oxygen carrier and LaFe 0.5 Ni 0.5 Performance diagram of methane chemical chaining to syngas using O3 oxygen carrier; Figure 6 LaFe 0.7 Ni 0.3 O3-3NaCl oxygen carrier and LaFe 0.7 Ni 0.3 Performance diagram of methane chemical chaining to syngas using O3 oxygen carrier; Figure 7 LaFe 0.6 Ni 0.4 O3-2NaCl oxygen carrier and LaFe0.6 Ni 0.4 Performance chart of methane chemical looping synthesis gas of O3 oxygen carrier. DETAILED DESCRIPTION
[0017] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, any modification, equivalent replacement, improvement, etc. of all other embodiments obtained by those skilled in the art without creative labor should be included in the protection scope of the present application.
[0018] As Figure 1 shown, the present application proposes a preparation method of sodium chloride-assisted synthesis of oxygen-rich vacancy perovskite oxygen carrier, and the steps are as follows: S1, nitric acid lanthanum, nitric acid iron and nitric acid nickel are mixed to obtain a preliminary raw material; in the composition of nitric acid lanthanum, nitric acid iron and nitric acid nickel, the sum of the molar ratio of iron and nickel is the same as the molar ratio of lanthanum; S2, sodium chloride is added to the preliminary raw material, and the mass ratio of the preliminary raw material to sodium chloride is: 1:1~3; after mixing, a preliminary mixture is obtained; S3, the preliminary mixture is ground, and after grinding for 10 minutes, it is placed in a tube furnace, and the tube furnace is heated from room temperature to 850℃ at a heating rate of 5℃ per minute under air atmosphere and calcined for 4 hours to obtain an intermediate product; S4, after natural cooling of the intermediate product, the naturally cooled intermediate product is washed with water for 5 times to remove the contained sodium chloride, and finally an oxygen-rich vacancy perovskite oxygen carrier is prepared.
[0019] Meanwhile, the present application also discloses an application of the oxygen-rich vacancy perovskite oxygen carrier, and the oxygen-rich vacancy perovskite oxygen carrier prepared by the above steps can be used in the preparation step of methane chemical looping synthesis gas.
[0020] In addition, the present application also discloses an application of sodium chloride in the synthesis of oxygen-rich vacancy perovskite oxygen carrier, and the sodium chloride can be applied to the synthesis and preparation step of the oxygen-rich vacancy perovskite oxygen carrier, and effectively improves the oxygen vacancy concentration of the perovskite oxygen carrier.
[0021] The effect of the perovskite oxygen carrier prepared by the present application will be verified by specific examples as follows; EMBODIMENT
[0022] Step 1: 3.57 grams of lanthanum nitrate, 1.99 grams of iron nitrate, 0.96 grams of nickel nitrate and 19.56 grams of sodium chloride were weighed and manually ground in a agate mortar for 10 minutes, and then placed in a tube furnace, and the tube furnace was heated from room temperature to 850 degrees at a rate of 5 degrees per minute under air atmosphere, and then the tube furnace was calcined at 850 degrees for 4 hours, and then the tube furnace was naturally cooled, and then the sodium chloride was removed by water washing for 5 times, and then LaFe 0.6 Ni 0.4 O3-3NaCl oxygen carrier was prepared.
[0023] The same procedure was used to prepare LaFe 0.6 Ni 0.4 O3 oxygen carrier without adding sodium chloride.
[0024] The above oxygen carriers were analyzed by XRD, and compared with LaFeO3 perovskite standard card PDF # 37-1493, and the results are shown in Figure 2 It can be seen that the prepared above oxygen carrier has a small part of other oxide crystal phase, and most of the XRD peaks are in good agreement with the standard peaks of LaFeO3 perovskite, and the XRD spectra of LaFe 0.6 Ni 0.4 O3 and LaFe 0.6 Ni 0.4 O3-3NaCl are basically similar, indicating that the addition of sodium chloride does not affect the formation of perovskite structure of the oxygen carrier, that is, sodium chloride can assist the synthesis of perovskite oxygen carrier.
[0025] At the same time, the above oxygen carriers were characterized by EPR, and the results are shown in Figure 3 It can be seen that the oxygen vacancy concentration of the prepared LaFe 0.6 Ni 0.4 O3-3NaCl oxygen carrier is higher than that of LaFe 0.6 Ni 0.4 O3 oxygen carrier, and the results show that sodium chloride can assist the synthesis of perovskite oxygen carrier with rich oxygen vacancies.
[0026] Step 2: The methane chemical chain synthesis gas reaction performance test of LaFe 0.6 Ni 0.4 O3-3NaCl oxygen carrier and LaFe 0.6 Ni 0.4 O3 oxygen carrier was carried out in a fixed bed reactor (quartz tube length of 420 mm, outer diameter of 12 mm, and inner diameter of 8 mm), and the amount of the above oxygen carrier was 1 gram.
[0027] First, under normal pressure, 100% nitrogen atmosphere, and 50 mL / min conditions, the fixed bed temperature is heated to the reaction temperature of 800 degrees Celsius at a heating rate of 10 degrees Celsius / min. After the temperature inside the tube stabilizes, the reduction step is carried out under the following conditions: the atmosphere is switched to a mixture of 60% methane / equilibrium nitrogen (50 mL / min), and the reaction is carried out at 800 degrees Celsius for 10 minutes.
[0028] For the oxidation step, the gas was switched to air at a flow rate of 50 mL / min and oxidized at 800°C for 5 minutes. The gas was collected in a gas bag and analyzed using a gas chromatograph. The results are as follows: Figure 4 As shown, LaFe 0.6 Ni 0.4 The O3 oxygen carrier achieved a methane conversion rate of 11.6%, a hydrogen selectivity of 3.3%, and produced no carbon monoxide. LaFe 0.6 Ni 0.4 The O3-3NaCl oxygen carrier achieved a methane conversion rate of 55.6%, a hydrogen selectivity of 75.4%, and a carbon monoxide selectivity of 22.7%.
[0029] The above results indicate that LaFe 0.6 Ni 0.4 The overall performance of O3-3NaCl oxygen carrier is better than that of LaFe. 0.6 Ni 0.4 O3 oxygen carriers, using sodium chloride to assist in the synthesis of oxygen-vacancy-rich perovskite oxygen carriers, help improve their catalytic performance. Example
[0030] Step 1: Weigh 3.57 g of lanthanum nitrate, 1.66 g of ferric nitrate, 1.19 g of nickel nitrate, and 19.26 g of sodium chloride. Grind them manually in an agate mortar for 10 minutes. Place the mortar in a tube furnace and heat it from room temperature to 850°C in air atmosphere at a heating rate of 5°C per minute. Calcinate at 850°C for 4 hours. After natural cooling, wash with water 5 times to remove sodium chloride, thus obtaining LaFe. 0.5 Ni 0.5 O3-3NaCl oxygen carrier.
[0031] Using the same steps, but without adding sodium chloride, LaFe was prepared. 0.5 Ni 0.5 O3 oxygen carrier.
[0032] Step 2 is the same as step 2 in Example 1; the result is as follows: Figure 5 As shown, LaFe 0.5 Ni 0.5 The O3 oxygen carrier achieved a methane conversion rate of 14.9%, a hydrogen selectivity of 2.7%, and produced no carbon monoxide. LaFe 0.5 Ni 0.5The methane conversion rate of the O3-3NaCl oxygen carrier was 43.8%, the hydrogen selectivity was 72.6%, and the carbon monoxide selectivity was 27.9%.
[0033] The results show that: LaFe 0.5 Ni 0.5 The overall performance of the O3-3NaCl oxygen carrier is better than that of the LaFe 0.5 Ni 0.5 O3 oxygen carrier. Example
[0034] Step 1: weigh 3.57 grams of lanthanum nitrate, 2.33 grams of iron nitrate, 0.72 grams of nickel nitrate, and 19.86 grams of sodium chloride, manually grind in a agate mortar for 10 minutes, place in a tube furnace, under air atmosphere, heat the tube furnace from room temperature to 850 degrees, the tube furnace heating rate is 5 degrees per minute, 850 degrees for 4 hours, natural cooling, water washing 5 times to remove sodium chloride, to prepare LaFe 0.7 Ni 0.3 O3-3NaCl oxygen carrier.
[0035] The same steps are adopted, without adding sodium chloride, to prepare LaFe 0.7 Ni 0.3 O3 oxygen carrier.
[0036] Step 2 is the same as step 2 of example 1; the results are shown as Figure 6 LaFe 0.7 Ni 0.3 The methane conversion rate of the O3 oxygen carrier is 14.2%, the hydrogen selectivity is 2.9%, and no carbon monoxide is produced. LaFe 0.7 Ni 0.3 The methane conversion rate of the O3-3NaCl oxygen carrier is 44%, the hydrogen selectivity is 66.7%, and the carbon monoxide selectivity is 55.6%.
[0037] The results show that: LaFe 0.7 Ni 0.3 The overall performance of the O3-3NaCl oxygen carrier is better than that of the LaFe 0.7 Ni 0.3 O3 oxygen carrier. Example
[0038] Step 1: weigh 4.46 grams of lanthanum nitrate, 2.49 grams of iron nitrate, 1.19 grams of nickel nitrate, and 16.31 grams of sodium chloride, manually grind in a agate mortar for 10 minutes, place in a tube furnace, under air atmosphere, heat the tube furnace from room temperature to 800 degrees, the tube furnace heating rate is 5 degrees per minute, 800 degrees for 3 hours, natural cooling, water washing 5 times to remove sodium chloride, to prepare LaFe 0.6 Ni 0.4O3-2NaCl oxygen carrier. The same procedure was used, without adding sodium chloride, to prepare LaFe 0.6 Ni 0.4 O3 oxygen carrier.
[0039] Step 2 same as step 2 of example 1; results are shown in table 1 Figure 7 LaFe 0.6 Ni 0.4 O3 oxygen carrier, the methane conversion was 11.6%, the hydrogen selectivity was 3.3%, and no carbon monoxide was produced. LaFe 0.6 Ni 0.4 O3-2NaCl oxygen carrier, the methane conversion was 56.22%, the hydrogen selectivity was 74.32%, and the carbon monoxide selectivity was 19.45%.
[0040] The results show that: LaFe 0.6 Ni 0.4 O3-2NaCl oxygen carrier is superior to LaFe 0.6 Ni 0.4 O3 oxygen carrier.
[0041] The present application has the following beneficial effects: 1. The perovskite oxygen carrier in the present application has a short preparation period, simple preparation steps, easy operation, and high preparation efficiency; 2. The raw materials are processed by solid phase grinding method, which can avoid the generation of waste liquid, reduce the preparation cost, and improve the environmental protection performance; 3. The present application uses sodium chloride to improve the oxygen vacancy of the perovskite oxygen carrier, which has low cost and is easy to obtain, and has good water solubility, so it is easy to remove and recover after reaction, further improving the preparation and production effect of the perovskite oxygen carrier; 4. In the process of sodium chloride assisted calcination preparation of the perovskite oxygen carrier in the present application, oxygen vacancies are generated in situ, and hydrogen gas reduction operation is not required, avoiding the problems of flammable and explosive hydrogen gas during preparation, effectively improving the safety of the oxygen vacancy generation process, and further improving the preparation effect of the perovskite oxygen carrier.
Claims
1. A method for preparing sodium chloride-assisted synthesis of oxygen-rich vacancy perovskite oxygen carrier, characterized in that: The method comprises the following steps: S1, mixing lanthanum compound, iron compound and nickel compound to obtain a preliminary raw material; S2, adding sodium chloride to the preliminary raw material to obtain a preliminary mixture; S3, grinding the preliminary mixture, and then placing the ground preliminary mixture in a tube furnace, and heating the tube furnace from room temperature to 800-850 DEG C under air atmosphere and calcining for 3-4 hours to obtain an intermediate product; S4, after natural cooling of the intermediate product, removing sodium chloride contained in the intermediate product by water washing to obtain an oxygen-rich vacancy perovskite oxygen carrier.
2. The method for preparing sodium chloride-assisted synthesis of oxygen- vacancy-rich perovskite oxygen carrier according to claim 1, characterized in that: In the step S1, the molar ratio of iron and nickel in the components of the lanthanum compound, the iron compound and the nickel compound is the same as the molar ratio of lanthanum.
3. The method for preparing sodium chloride-assisted synthesis of oxygen- vacancy-rich perovskite oxygen carrier according to claim 1, characterized in that: In the step S1, the lanthanum compound is lanthanum nitrate, the iron compound is ferric nitrate, and the nickel compound is nickel nitrate.
4. The method for preparing sodium chloride-assisted synthesis of oxygen- vacancy-rich perovskite oxygen carrier according to claim 1, characterized in that: In the step S2, the mass ratio of the sum of the mass of the lanthanum compound, the iron compound and the nickel compound to the mass of sodium chloride is 1:1-3.
5. The method for preparing sodium chloride-assisted synthesis of oxygen- vacancy-rich perovskite oxygen carrier according to claim 1, characterized in that: In the step S3, when the tube furnace is heated from room temperature to 800-850 DEG C, the heating rate is 5-10 DEG C per minute.
6. The method for preparing sodium chloride-assisted synthesis of oxygen- vacancy-rich perovskite oxygen carrier according to claim 1, characterized in that: In the step S4, the intermediate product after natural cooling is washed with water for 5 times.
7. The use of an oxygen-rich vacancy perovskite oxygen carrier prepared by the method of claim 1 for the synthesis of an oxygen-rich vacancy perovskite oxygen carrier with the aid of sodium chloride, characterized in that: The oxygen-rich vacancy perovskite oxygen carrier can be used in the preparation step of preparing synthesis gas by methane chemical chain.
8. Use of sodium chloride in the synthesis of oxygen-rich vacancy perovskite oxygen carriers, characterized by: The sodium chloride can be applied to the synthesis and preparation step of the oxygen-rich vacancy perovskite oxygen carrier.