Manganese modified pelelith denitration catalyst as well as preparation method and application thereof
By preparing a manganese-modified volcanic rock denitration catalyst, the problems of high denitration temperature and high cost of existing SCR catalysts were solved, realizing low-temperature high-efficiency denitration and the application of environmentally friendly materials, and reducing production costs.
Patent Information
- Application Number
- CN202411532830.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-30
- Publication Date
- 2025-01-07
AI Technical Summary
Existing SCR catalysts suffer from problems such as high denitrification temperature, high production cost, and vanadium biotoxicity that can easily cause secondary pollution. There is a need to develop new SCR catalysts that are inexpensive, efficient, low-temperature, and environmentally friendly.
The denitrification catalyst using manganese-modified volcanic rock is prepared by combining volcanic rock with manganese oxide. The preparation method includes steps such as stirring, solid-liquid separation, washing, drying, impregnation, and calcination to form a porous structure to enhance catalytic activity.
It maintains good denitrification effect in a lower temperature range (150-200 ℃), reduces production costs, reduces environmental risks, and realizes diversified utilization and application of environmentally friendly materials.
Smart Images
Figure FT_1 
Figure FT_2 
Figure SMS_1
Abstract
Description
Technical Field
[0001] The invention relates to the field of nitrogen oxide control, mineral utilization and catalytic technology, and in particular to a manganese-modified volcanic rock denitration catalyst and a preparation method and application thereof. Background Art
[0002] Nitrogen oxides are one of the main air pollutants in the world, with serious health and environmental hazards. Therefore, reducing nitrogen oxide emissions is crucial to improving air quality and protecting public health. Current technologies for controlling nitrogen oxides mainly include selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR) and other technologies. Among them, NH3-SCR technology is an efficient method for controlling nitrogen oxide emissions. The denitrification effect of this technology mainly depends on the performance of the catalyst. At present, most commercial SCR catalysts use V2O5-WO3 / TiO2, but these catalysts have many problems such as high denitrification temperature, high production cost, and vanadium biotoxicity that easily causes secondary pollution. Therefore, it is necessary to develop a new type of SCR catalyst that is cheap, efficient, low-temperature and environmentally friendly. Summary of the invention
[0003] In view of the problems existing in the above-mentioned prior art, the present invention provides a manganese-modified volcanic rock denitrification catalyst and a preparation method and application thereof. The manganese-modified volcanic rock denitrification catalyst can maintain a good denitrification effect within a relatively low temperature range.
[0004] The present invention is achieved through the following technical solutions: The invention provides a manganese-modified volcanic rock denitration catalyst, wherein the catalyst is a composite of volcanic rock and manganese oxide.
[0005] The method for preparing the manganese-modified volcanic rock denitration catalyst of the present invention comprises the following steps: (1) mixing volcanic rock powder and nitric acid, and then separating the solid and liquid, and washing and drying the obtained solid to obtain acidified volcanic rock powder; (2) adding the acidified volcanic rock powder into a manganese salt solution for impregnation, then separating the solid from the liquid, and washing and drying the obtained solid to obtain manganese-modified volcanic rock powder; (3) calcining the manganese-modified volcanic rock powder in an inert atmosphere to obtain a manganese-modified volcanic rock denitrification catalyst.
[0006] Preferably, in step (1), the stirring and mixing time is 4-6 h.
[0007] Preferably, in step (1) and step (2), washing is performed until the pH of the filtrate is neutral.
[0008] Preferably, in step (2), the manganese salt solution is a manganese nitrate solution.
[0009] Preferably, in step (2), the immersion time is 8-12.
[0010] Preferably, in step (3), the calcination temperature is 300-450°C.
[0011] Preferably, in step (3), the heating rate of calcination is 2-5 °C / min.
[0012] Preferably, in step (3), the calcination time is 1-3 hours.
[0013] The present invention also provides application of the manganese-modified volcanic rock denitration catalyst in catalytic denitration.
[0014] Compared with the prior art, the present invention has the following beneficial effects: The catalyst of the present invention is a composite of volcanic rock and manganese oxide. Volcanic rock is a natural porous material, mainly composed of silicate, aluminate and other mineral components, such as silicon dioxide, aluminum oxide, iron oxide, etc. Metal oxides such as iron oxide and aluminum oxide have certain denitrification activity and can participate in the catalytic reaction as active components in the catalytic reaction. Volcanic rock has a porous structure and a large specific surface area. Its natural pore structure is conducive to gas diffusion, which can enhance the contact between nitrogen oxides and the catalyst surface and improve the reaction efficiency. Therefore, the present invention uses volcanic rock and manganese oxide as a denitrification catalyst, which can maintain a good denitrification effect within a relatively low temperature range (150-200 ° C). In addition, volcanic rock is a cheap and abundant natural material. Its application can significantly reduce the production cost of denitrification catalysts, which is conducive to large-scale application. Volcanic rock and manganese are both environmentally friendly materials. Using them to prepare denitrification catalysts reduces dependence on toxic metals (such as vanadium) and reduces environmental risks. Therefore, the catalyst has good application prospects in the field of nitrogen oxide control.
[0015] The catalyst is prepared by grinding, acidification, impregnation and calcination. -1 , within the range of 150-250°C, the NO conversion rate exceeds 80%. The preparation method of the present invention is simple, realizes the diversified utilization of volcanic rocks, is not only beneficial to environmental protection, but also can reduce the production cost of denitration catalysts. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0017] Figure 1This is a SEM image of the catalyst obtained in Example 1 of the present invention.
[0018] Figure 2 It is the XRD spectrum of the catalyst obtained in Example 1 of the present invention. DETAILED DESCRIPTION
[0019] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.
[0020] It should be noted that the process equipment or devices not specifically specified in the following embodiments are all conventional equipment or devices in the art.
[0021] It should be noted that the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to define the scope of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of the present invention without substantially changing the technical content.
[0022] The manganese-modified volcanic rock denitration catalyst provided by the present invention is a composite of volcanic rock and manganese oxide.
[0023] The method for preparing the manganese-modified volcanic rock denitration catalyst of the present invention comprises the following steps: (1) mixing volcanic rock powder and nitric acid, and then separating the solid and liquid, and washing and drying the obtained solid to obtain acidified volcanic rock powder; (2) adding the acidified volcanic rock powder into a manganese salt solution for impregnation, then separating the solid from the liquid, and washing and drying the obtained solid to obtain manganese-modified volcanic rock powder; (3) calcining the manganese-modified volcanic rock powder in an inert atmosphere to obtain a manganese-modified volcanic rock denitrification catalyst.
[0024] In step (1) of the present invention, the stirring and mixing time is 4-6 hours, so that the volcanic rock powder and nitric acid can fully contact and react.
[0025] In step (1) and step (2) of the present invention, the solid-liquid separation is specifically carried out by suction filtration, and the washing is specifically carried out by washing with deionized water until the pH of the filtrate is neutral.
[0026] The manganese salt solution used in step (2) of the present invention is preferably a manganese nitrate solution. The solid-liquid ratio of volcanic rock powder to manganese nitrate solution is 1: (20-40), and the concentration of manganese nitrate solution is 5-15%.
[0027] In step (2) of the present invention, the acidified volcanic stone powder is immersed in the manganese salt solution for 8-12 seconds to ensure sufficient immersion.
[0028] In step (3) of the present invention, the calcination temperature is 300-450°C, the calcination time is 1-3 h, and the calcination heating rate is 2-5°C / min.
[0029] In step (3) of the present invention, the inert atmosphere may be nitrogen, helium or argon.
[0030] The manganese-modified volcanic rock denitrification catalyst is used in catalytic denitrification.
[0031] Example 1, preparation of manganese-modified volcanic rock denitrification catalyst.
[0032] In the first step, volcanic rock was processed with a grinder to obtain volcanic rock powder, and then the volcanic rock powder was pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally the rinsed volcanic rock powder was dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, marked as AVR.
[0033] In the second step, manganese was loaded on AVR by impregnation method: AVR and 10% manganese nitrate solution were mixed at a solid-liquid ratio of 1:30, stirred at room temperature for 10 h, and then filtered. The volcanic stone powder was rinsed with deionized water until the pH of the filtrate reached 7.0. Finally, the rinsed volcanic stone powder was dried in an oven (85 °C) for 24 h to obtain manganese-modified volcanic stone powder. The powder was calcined at 450 °C for 2 h at a heating rate of 2 °C / min under nitrogen atmosphere, ground and sieved to 40-60 mesh, and labeled as AVR-Mn-450(2).
[0034] Example 2, preparation of manganese-modified volcanic rock denitrification catalyst.
[0035] In the first step, volcanic rock was processed with a grinder to obtain volcanic rock powder, and then the volcanic rock powder was pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally the rinsed volcanic rock powder was dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, marked as AVR.
[0036] In the second step, manganese was loaded on AVR by impregnation method: AVR and 10% manganese nitrate solution were mixed at a solid-liquid ratio of 1:30, stirred at room temperature for 10 h, and then filtered. The volcanic stone powder was rinsed with deionized water until the pH of the filtrate reached 7.0. Finally, the rinsed volcanic stone powder was dried in an oven (85 °C) for 24 h to obtain manganese-modified volcanic stone powder. The powder was calcined at 300 °C for 2 h at a heating rate of 2 °C / min under nitrogen atmosphere, ground and sieved to 40-60 mesh, and labeled as AVR-Mn-300(2).
[0037] Example 3, preparation of manganese-modified volcanic rock denitrification catalyst.
[0038] In the first step, volcanic rock was processed with a grinder to obtain volcanic rock powder, and then the volcanic rock powder was pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally the rinsed volcanic rock powder was dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, marked as AVR.
[0039] In the second step, manganese was loaded on AVR by impregnation method: AVR and 10% manganese nitrate solution were mixed at a solid-liquid ratio of 1:30, stirred at room temperature for 10 h, and then filtered. The volcanic stone powder was rinsed with deionized water until the pH of the filtrate reached 7.0. Finally, the rinsed volcanic stone powder was dried in an oven (85 °C) for 24 h to obtain manganese-modified volcanic stone powder. The powder was calcined at 350 °C for 2 h at a heating rate of 2 °C / min under nitrogen atmosphere, ground and sieved to 40-60 mesh, and labeled as AVR-Mn-350(2).
[0040] Example 4, preparation of manganese-modified volcanic rock denitrification catalyst.
[0041] In the first step, volcanic rock was processed with a grinder to obtain volcanic rock powder, and then the volcanic rock powder was pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally the rinsed volcanic rock powder was dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, marked as AVR.
[0042] In the second step, manganese was loaded on AVR by impregnation method: AVR and 10% manganese nitrate solution were mixed at a solid-liquid ratio of 1:30, stirred at room temperature for 10 h, and then filtered. The volcanic stone powder was rinsed with deionized water until the pH of the filtrate reached 7.0. Finally, the rinsed volcanic stone powder was dried in an oven (85 °C) for 24 h to obtain manganese-modified volcanic stone powder, which was calcined at 400 °C for 2 h at a heating rate of 2 °C / min under nitrogen atmosphere, ground and sieved to 40-60 mesh, and labeled as AVR-Mn-400(2).
[0043] Example 5, preparation of manganese-modified volcanic rock denitrification catalyst.
[0044] In the first step, volcanic rock was processed with a grinder to obtain volcanic rock powder, and then the volcanic rock powder was pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally the rinsed volcanic rock powder was dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, marked as AVR.
[0045] In the second step, manganese was loaded on AVR by impregnation method: AVR and 10% manganese nitrate solution were mixed at a solid-liquid ratio of 1:30, stirred at room temperature for 10 h, and then filtered. The volcanic stone powder was rinsed with deionized water until the pH of the filtrate reached 7.0. Finally, the rinsed volcanic stone powder was dried in an oven (85 °C) for 24 h to obtain manganese-modified volcanic stone powder, which was calcined at 450 °C for 3 h at a heating rate of 2 °C / min under nitrogen atmosphere, ground and sieved to 40-60 mesh, and labeled as AVR-Mn-450(3).
[0046] Example 6, preparation of manganese-modified volcanic rock denitrification catalyst.
[0047] In the first step, volcanic rock was processed with a grinder to obtain volcanic rock powder, and then the volcanic rock powder was pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally the rinsed volcanic rock powder was dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, marked as AVR.
[0048] In the second step, manganese was loaded on AVR by impregnation method: AVR and 10% manganese nitrate solution were mixed at a solid-liquid ratio of 1:30, stirred at room temperature for 10 h, and then filtered. The volcanic stone powder was rinsed with deionized water until the pH of the filtrate reached 7.0. Finally, the rinsed volcanic stone powder was dried in an oven (85 °C) for 24 h to obtain manganese-modified volcanic stone powder. The powder was calcined at 450 °C for 1 h at a heating rate of 2 °C / min under nitrogen atmosphere, ground and sieved to 40-60 mesh, and labeled as AVR-Mn-450(1).
[0049] Comparative Example 1 Volcanic rock was processed with a grinder to obtain volcanic rock powder, which was then pretreated with nitric acid: volcanic rock powder and 2 mol / L nitric acid were mixed in a solid-liquid ratio of 1:6, stirred at room temperature for 6 h, then filtered, rinsed with deionized water until the filtrate pH reached 7.0, and finally dried in an oven (85 °C) for 24 h to obtain acidified volcanic rock powder, labeled as AVR.
[0050] The SEM and XRD images of the manganese-modified volcanic rock denitration catalyst AVR-Mn-450 prepared in Example 1 of the present invention are as follows: Figure 1 , Figure 2 As shown. Figure 1 It can be seen that the surface of manganese-modified volcanic rock denitrification catalyst AVR-Mn-450 is uneven and has a large number of pores. Figure 2 It can be seen that the manganese-modified volcanic rock denitrification catalyst AVR-Mn-450 has characteristic peaks of iron oxides and manganese oxides.
[0051] The catalysts obtained in Examples 1-6 and Comparative Example 1 and the original volcanic rocks were tested for denitrification effects. The test conditions were as follows: 500 ppm NO, 500 ppm NH3, 5% vol O2, N2 as the balance gas, gas flow rate of 50 mL / min, and space velocity (GHSV) of 25000 h -1 , the test temperature range is 100-250 ℃. The test results are shown in Table 1.
[0052] Table 1 Denitration of catalysts obtained in various examples
[0053] As can be seen from the above table, the denitration effect of the AVR-Mn-450 series catalysts prepared in the embodiment of the present invention is significantly better than that of the acidified volcanic rock AVR and the original volcanic rock, among which the NO conversion rate of AVR-Mn-450 (2) exceeds 80% in the range of 150-200 ° C, indicating that the prepared manganese-modified volcanic rock denitration catalyst has good denitration activity in the low temperature range. It can also be seen that as the calcination temperature decreases, the catalytic activity of the manganese-modified volcanic rock denitration catalyst decreases, and the optimal calcination time is 2h.
[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A manganese-modified volcanic rock denitrification catalyst, characterized in that: The catalyst is a composite of volcanic rock and manganese oxide.
2. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 1, characterized in that: The following steps are involved: (1) mixing volcanic rock powder and nitric acid, and then separating the solid and liquid, and washing and drying the obtained solid to obtain acidified volcanic rock powder; (2) adding the acidified volcanic rock powder into a manganese salt solution for impregnation, then separating the solid from the liquid, and washing and drying the obtained solid to obtain manganese-modified volcanic rock powder; (3) calcining the manganese-modified volcanic rock powder in an inert atmosphere to obtain a manganese-modified volcanic rock denitrification catalyst.
3. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (1), the stirring and mixing time is 4-6 h.
4. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (1) and step (2), washing is performed until the pH of the filtrate is neutral.
5. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (2), the manganese salt solution is a manganese nitrate solution.
6. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (2), the dipping time is 8-12.
7. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (3), the calcination temperature is 300-450°C.
8. The method for preparing the manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (3), the heating rate of calcination is 2-5 °C / min.
9. The method for preparing a manganese-modified volcanic rock denitration catalyst according to claim 2, characterized in that: In step (3), the calcination time is 1-3 hours.
10. Use of the manganese-modified volcanic rock denitrification catalyst according to claim 1 in catalytic denitrification.