Cerium-manganese catalyst for low-temperature propane catalytic combustion as well as preparation method and application of cerium-manganese catalyst

Abstract

The invention discloses a cerium-manganese catalyst for low-temperature propane catalytic combustion as well as a preparation method and application of the cerium-manganese catalyst. According to the method, a continuous method is utilized under stirring, ammonium oxalate is used as a precipitator, manganese sulfate is used as a main catalytic active component, cerium sulfate is used as a trace auxiliary agent, and the invention aims at providing a stable and efficient preparation method of the cerium-manganese catalyst and realizing efficient degradation of propane catalytic combustion under a low-temperature condition. The technical scheme is as follows: (1) preparing a mixed solution A of manganese sulfate and cerous sulfate; (2) preparing an ammonium oxalate aqueous solution B; (3) uniformly stirring the uniform solution at normal temperature for 15 minutes; (4) respectively pumping the solution A and the solution B into a peristaltic pump A and a peristaltic pump B, and mixing and outputting along with a pipeline; (5) centrifuging, washing with deionized water and alcohol, and drying at 60 DEG C to obtain a solid product; and (6) further calcining the solid product in a muffle furnace to obtain a finished product. Relates to the technical fields of petrochemical engineering, thermocatalytic materials and environmental protection.

Description

Technical Field

[0001] This invention relates to a catalyst, specifically a cerium-manganese catalyst for low-temperature propane catalytic combustion, and also to a method for preparing the cerium-manganese catalyst, belonging to the fields of petrochemicals, thermocatalytic materials, and environmental protection technology. Background Technology

[0002] Propane, a substance produced in large quantities in industrial waste gas and automobile exhaust, is one of the most stable and difficult-to-remove alkanes. Its direct emission can easily cause atmospheric photochemical pollution, the greenhouse effect, and harm to human health. Therefore, achieving efficient propane purification has become an important research direction in the fields of industrial waste gas treatment and environmental catalysis. Catalytic complete oxidation is the mainstream technology for the harmless treatment of propane, which can directionally convert propane into CO2 and H2O at relatively low temperatures. Currently, propane oxidation catalysts are mainly divided into noble metal catalysts and non-noble metal catalysts. While noble metal catalysts exhibit excellent low-temperature activity, they suffer from high raw material costs, susceptibility to sintering at high temperatures, and poor resistance to poisoning, making it difficult to meet the needs of large-scale industrial applications.

[0003] In recent years, cerium-based materials in transition metals have been frequently used as promoters in combination with manganese-based oxides to enhance catalytic performance due to their excellent oxygen storage and release capabilities, oxygen vacancy regulation effects, and structural stabilization. However, existing cerium-manganese catalysts mostly employ traditional batch preparation processes, which suffer from problems such as uneven distribution of metal components, weak interfacial bonding strength, and easy sintering of grains during calcination. This results in a lack of prominent Ce-O-Mn synergistic effects, limited generation and recycling efficiency of surface active oxygen species, and the low-temperature propane oxidation activity and stability still failing to meet the requirements of practical operating conditions. Furthermore, existing preparation processes struggle to achieve precise doping of active components and uniform precipitation of precursors, further limiting the optimization of catalyst oxygen transport capacity and catalytic kinetics.

[0004] Therefore, developing a cerium-manganese bimetallic catalyst with simple preparation process, uniform component dispersion, high low-temperature activity, and good stability to achieve efficient and complete oxidation of propane under mild conditions is of great practical significance and application value for improving the efficiency of industrial VOCs treatment and reducing catalytic purification costs. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method for preparing a cerium-manganese catalyst that exhibits high catalytic activity for propane combustion under low-temperature conditions, based on the current challenges faced by transition metal-based catalysts.

[0006] To achieve the above objectives, the first technical solution provided by the present invention is as follows: A method for preparing a cerium-manganese catalyst includes the following steps: (1) Prepare a mixed solution A of manganese sulfate and cerium sulfate; (2) Prepare ammonium oxalate aqueous solution B; (3) Stir the above homogeneous solution at room temperature ℃ for 15 min; (4) Pump the resulting solutions A and B into peristaltic pumps A and B respectively, and mix them with the pipeline to produce the solution; (5) Centrifuge, wash with deionized water and alcohol, and dry at 60° to obtain a solid product. (6) The above solid product is further calcined in a muffle furnace to obtain the finished product; this involves the fields of petrochemicals, thermocatalytic materials, and environmental protection technologies.

[0007] Furthermore, in the above-mentioned method for preparing the cerium-manganese catalyst, the molar ratio of cerium sulfate and manganese sulfate in step (1) is 1:50 (mmol).

[0008] Furthermore, in the above-mentioned method for preparing the cerium-manganese catalyst, the ammonium oxalate aqueous solution mentioned in step (2) is saturated ammonium oxalate.

[0009] Furthermore, in the above-mentioned method for preparing the cerium-manganese catalyst, the stirring speed in step (3) is 800 r / min.

[0010] Furthermore, in the above-mentioned method for preparing cerium-manganese catalyst, the flow rate of the peristaltic pump in step (4) is 30~50 ml / min.

[0011] Furthermore, in the preparation method of the above-mentioned cerium-manganese catalyst, the centrifugation parameters in step (5) are: 8000 r / min, time 5 min; the washing conditions are: washing 3 times each with deionized water and ethanol; the drying temperature is 60℃, and the time is 12 h.

[0012] Furthermore, in the above-mentioned method for preparing cerium-manganese catalyst, the calcination temperature in step (6) is 300℃ and the calcination time is 2h.

[0013] The second technical solution provided by the present invention is to use a cerium-manganese catalyst prepared by the above method for catalysis.

[0014] The catalyst is used to catalyze the combustion of propane. The catalytic conditions are as follows: the feed gas composition is 5% propane, 20% oxygen, and the remainder is nitrogen, the space velocity is 30000 mL / (g·h), and the reaction temperature is 180-200℃.

[0015] The CMO provided by this invention x The catalyst is used in the field of low-temperature thermocatalysis.

[0016] Compared with the prior art, the technical solution provided by the present invention has the following specific technical advantages: (1) The preparation process uses only transition metals, which greatly reduces the cost; (2) Formation of Ce-O-Mn interface active sites, significantly increasing oxygen vacancies, promoting rapid generation and efficient cycling of reactive oxygen species, reducing reaction energy barrier, and greatly improving the activity of catalyst for complete low-temperature propane oxidation; (3) The preparation conditions are simple and the operation is convenient. It can be continuously scaled up in industrial production. Attached Figure Description

[0017] Figure 1 CMO x Schematic diagram of catalyst synthesis; Figure 2 CMO x Catalyst activity diagram for propane catalytic combustion; Figure 3 CMO x Scanning electron microscope (SEM) image of the catalyst. Detailed Implementation

[0018] The technical solution of the present invention will be described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0019] Example 1 This embodiment provides a CMO for thermocatalytic propane combustion. x The catalyst is prepared by the following method: (1) Take 0.405gCe(SO4)2 and 8.54gMnSO4 and add them to 50mL of deionized water respectively. After stirring evenly, pour the cerium sulfate aqueous solution into the manganese sulfate aqueous solution and record it as mixed solution A. (2) Take 7.815g of (NH4)2C2O4 and add it to 100ml of deionized water, and record it as solution B; (3) Place the obtained solution on a magnetic stirrer and stir at 800 r / min for 15 min at room temperature; (4) Pump the well-stirred solutions A and B into peristaltic pumps A and B respectively. The flow rate of the peristaltic pumps is 30~50ml / min, and the solutions are mixed and produced through the pipeline. (5) Centrifuge, wash with deionized water and ethanol, and vacuum dry to obtain solid product. Centrifugation parameters: 8000 r / min, time 5 min; washing conditions: wash with deionized water and ethanol 3 times each; drying temperature: 60℃, time 12 h. (6) The above solid product was calcined in air at a temperature of 300°C for 2 hours to obtain the final product. The resulting sample is denoted as C1M. 50 O x .

[0020] Example 2 This embodiment provides a CMO for thermocatalytic propane combustion. x The catalyst is prepared by the following method: (1) Take 0.405gCe(SO4)2 and 0.171gMnSO4 and add them to 50mL of deionized water respectively. After stirring evenly, pour the cerium sulfate aqueous solution into the manganese sulfate aqueous solution and record it as mixed solution A. (2) Take 7.815g of (NH4)2C2O4 and add it to 100ml of deionized water, and record it as solution B; (3) Place the obtained solution on a magnetic stirrer and stir at 800 r / min for 15 min at room temperature; (4) Pump the well-stirred solutions A and B into peristaltic pumps A and B respectively. The flow rate of the peristaltic pumps is 30~50ml / min, and the solutions are mixed and produced through the pipeline. (5) Centrifuge, wash with deionized water and ethanol, and vacuum dry to obtain solid product. Centrifugation parameters: 8000 r / min, time 5 min; washing conditions: wash with deionized water and ethanol 3 times each; drying temperature: 60℃, time 12 h. (6) The above solid product was calcined in air at a temperature of 300°C for 2 hours to obtain the final product. The resulting sample is designated as C1M1O. x .

[0021] Example 3 This embodiment provides a CMO for thermocatalytic propane combustion. x The catalyst is prepared by the following method: (1) Take 0.405gCe(SO4)2 and 17.07gMnSO4 and add them to 50mL of deionized water respectively. After stirring evenly, pour the cerium sulfate aqueous solution into the manganese sulfate aqueous solution and record it as mixed solution A. (2) Take 7.815g of (NH4)2C2O4 and add it to 100ml of deionized water, and record it as solution B; (3) Place the obtained solution on a magnetic stirrer and stir at 800 r / min for 15 min at room temperature; (4) Pump the well-stirred solutions A and B into peristaltic pumps A and B respectively. The flow rate of the peristaltic pumps is 30~50ml / min, and the solutions are mixed and produced through the pipeline. (5) Centrifuge, wash with deionized water and ethanol, and vacuum dry to obtain solid product. Centrifugation parameters: 8000 r / min, time 5 min; washing conditions: wash with deionized water and ethanol 3 times each; drying temperature: 60℃, time 12 h. (6) The above solid product was calcined in air at a temperature of 300°C for 2 hours to obtain the final product. The resulting sample is denoted as C1M.100 O x 。

[0022] Example 4 A CMO catalyst for thermal catalytic propane combustion provided in this example x The preparation method of the catalyst is prepared by the following method: (1) Take 08.54 g of MnSO4 and add it to 50 mL of deionized water. After stirring evenly, pour the cerium sulfate aqueous solution into the manganese sulfate aqueous solution, and record it as mixed solution A; (2) Take 7.815 g of (NH4)2C2O4 and add it to 100 ml of deionized water, and record it as solution B; (3) Place the obtained solution on a magnetic stirrer and stir at 800 r / min for 15 min at room temperature; (4) Pump the evenly stirred solutions A and B into peristaltic pumps A and B respectively. The flow rate of the peristaltic pump is: 30 - 50 ml / min, and it is produced by mixing along the pipeline; (5) Centrifuge, wash with deionized water and ethanol, and dry in vacuum to obtain a solid product. The centrifuge parameters are: 8000 r / min, time 5 min; the washing conditions are: wash with deionized water and ethanol 3 times each; the drying temperature is 60 °C, and the time is 12 h; (6) Calcinate the above solid product in an air atmosphere to obtain the finished product. The calcination temperature is 300 °C, and the calcination time is 2 h. The obtained sample is designated as MnO x 。

[0023] The catalyst activity is expressed by the propane conversion rate, and the propane conversion rate is calculated by the following formula. Where is the concentration at the inlet of the gas chromatograph, is the concentration at the outlet of the gas chromatograph.

[0024]

[0025] Apply the prepared cerium-manganese catalyst to the propane catalytic combustion reaction. Weigh 200 mg of CMOx and mix it with 800 mg of quartz sand in a quartz tube配套 with a fixed bed. React under the conditions of 100 °C - 300 °C, atmospheric pressure, and a space velocity of 30000 h-1. The gas after the reaction is monitored in real time by gas chromatography to analyze the propane conversion rate, Figure 1 is the performance diagram of propane catalytic combustion, with relatively excellent performance.

[0026] The above is only the preferred embodiment of the present invention. It should be noted that for those skilled in the art, without departing from the structure of the present invention, several modifications and improvements can be made, which will not affect the implementation effect of the present invention and the practicality of the patent.

Claims

1. A cerium-manganese catalyst for low-temperature propane catalytic combustion, its preparation method, and its application, characterized in that, The steps are as follows: (1) Prepare a mixed solution A of manganese sulfate and cerium sulfate; (2) Prepare ammonium oxalate aqueous solution B; (3) Stir the above homogeneous solution at room temperature ℃ for 15 min; (4) Pump the resulting solutions A and B into peristaltic pumps A and B respectively, and mix them with the pipeline to produce the solution; (5) Centrifuge, wash with deionized water and alcohol, and dry at 60° to obtain a solid product; (6) The above solid product is further calcined in a muffle furnace to obtain the finished product; this involves the fields of petrochemicals, thermocatalytic materials, and environmental protection technologies.

2. The method for preparing the cerium-manganese catalyst according to claim 1, characterized in that, The molar ratio of cerium sulfate and manganese sulfate in step (1) is 1:50 (mmol).

3. The method for preparing the cerium-manganese catalyst according to claim 1, characterized in that, The ammonium oxalate aqueous solution mentioned in step (2) is saturated ammonium oxalate.

4. The method for preparing the cerium-manganese catalyst according to claim 1, characterized in that, The stirring speed mentioned in step (3) is 800 r / min.

5. The method for preparing the cerium-manganese catalyst according to claim 1, characterized in that, The flow rate of the peristaltic pump mentioned in step (4) is 30~50 ml / min.

6. The method for preparing the cerium-manganese catalyst according to claim 1, characterized in that, In step (5), the centrifugation parameters are: 8000 r / min, time 5 min; the washing conditions are: washing 3 times each with deionized water and ethanol; the drying temperature is 60℃, and the time is 12 h.

7. The method for preparing the cerium-manganese catalyst according to claim 1, characterized in that, The calcination temperature in step (6) is 300℃ and the calcination time is 2h.

8. A cerium-manganese catalyst, characterized in that, Prepared using the method described in any one of claims 1-7.

9. A method for the complete low-temperature catalytic oxidation of propane using the cerium-manganese catalyst as described in claim 8, characterized in that, The catalytic conditions are as follows: the feed gas composition is 5% propane, 20% oxygen, and the remainder is nitrogen, the space velocity is 30000 mL / (g·h), and the reaction temperature is 100-300℃.

10. The cerium-manganese catalyst provided by this invention is applicable to the field of thermocatalysis. The catalyst can be used for the efficient degradation of propane through low-temperature catalytic combustion.

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