Low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition as well as preparation method and application of low-temperature NH3-SCR catalyst
MnAl catalyst was prepared by mixing Mn2O3 with γ-Al2O3, which solved the problem of deactivation of manganese-based catalysts by ammonium nitrate deposition under low temperature conditions, and achieved efficient low-temperature denitrification performance and stability.
Patent Information
- Application Number
- CN202411674331.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-21
- Publication Date
- 2025-02-25
AI Technical Summary
The prior art is difficult to effectively alleviate the deactivation problem of manganese-based catalysts by ammonium nitrate deposition under low temperature conditions, resulting in a decrease in the stability and activity of the catalyst in the flue gas denitrition process in the non-electric industry.
MnAl catalyst was prepared by mixing the ground Mn2O3 with γ-Al2O3 and drying at 100°C, which had excellent low-temperature catalytic properties and anti-ammonium nitrate precipitation properties.
The efficient denitrification performance and stability of manganese-based catalysts are achieved under low temperature conditions below 150°C, which avoids the deposition of ammonium nitrate on the catalyst and improves the catalytic activity and reaction stability.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of flue gas denitrification, and particularly relates to a low-temperature NH 3 -SCR catalyst and its preparation method and application. Background Art
[0002] In recent years, along with the progress of my country's industrialization, air pollution problems represented by smog weather have become increasingly serious. x ) is one of the important air pollutants, mainly from the combustion of fossil fuels such as coal. Due to the popularization of wet desulfurization technology in flue gas in non-power industries, the flue gas temperature has decreased, and in some industries it has even reached below 150°C. The current vanadium tungsten titanium catalyst cannot meet the needs of this temperature range. Due to the excellent low-temperature performance of manganese-based catalysts, industrial pilot applications have been carried out. However, the deposition of ammonium nitrate caused by the decrease in temperature will cause the manganese-based catalyst to deactivate. How to alleviate nitrate poisoning is crucial to improving the low-temperature stability of the catalyst.
[0003] Mechanochemistry is a simple and green method for the synthesis of solid catalysts, which is also applicable to the preparation of manganese-based denitrification catalysts. In the mechanochemical process, the precursors are mixed together by ball milling or manual grinding to obtain the target catalyst material.
[0004] Therefore, it is necessary to provide a low-temperature NH 3 -SCR catalyst. Summary of the invention
[0005] In view of the above problems existing in the prior art, the first technical problem to be solved by the present invention is to provide a low-temperature NH 3 -SCR catalyst, the catalyst has excellent low temperature catalytic performance and resistance to ammonium nitrate precipitation. The second technical problem to be solved by the present invention is to provide a low temperature NH 3 -SCR catalyst preparation method, the method is simple and convenient, no secondary pollution. The third technical problem to be solved by the present invention is to provide a low-temperature NH 3 -The application of SCR catalyst in flue gas denitrification in non-electricity industries is used to treat flue gas denitrification in non-electricity industries.
[0006] In order to solve the above problems, the technical solution adopted by the present invention is as follows:
[0007] A low-temperature NH 3 -SCR catalyst, the catalyst is prepared by: grinding Mn 2 O 3 Drying with γ-Al 2 O 3The mixture was mixed and ground, and then dried to obtain MnAl catalyst, i.e., low-temperature NH 3 -SCR catalyst.
[0008] A low-temperature NH 3 -SCR catalyst preparation method, the ground Mn 2 O 3 Drying with γ-Al 2 O 3 The mixture is mixed and then dried to obtain a MnAl catalyst, i.e., a low-temperature NH 3 -SCR catalyst; the Mn 2 O 3 With γ-Al 2 O 3 The mass ratio is 1:1.
[0009] Furthermore, the ground Mn 2 O 3 Dry at 100°C for 2h.
[0010] Furthermore, the mixture is dried at a temperature of 100°C.
[0011] Furthermore, the mixture is dried for 2 hours.
[0012] Furthermore, the Mn 2 O 3 With γ-Al 2 O 3 The mixing time was 30 min.
[0013] The low temperature NH 3 -Application of SCR catalyst in flue gas denitrification in non-power industry.
[0014] Furthermore, the catalytic conditions for flue gas denitrification in the non-power industry are: the catalyst particle size is 40-60 mesh, and the reaction gas composition is 500ppm NO, 500ppm NH 3 and 4% O 2 , Ar was used as the balance gas, and the gas space velocity in the reaction was 60000 mL·g -1 ·h -1 .
[0015] Furthermore, the catalyst was purged with high-purity Ar at 200° C. for 0.5 h before the reaction.
[0016] Furthermore, the temperature of the catalytic reaction is 60-270°C.
[0017] Beneficial effects: Compared with the prior art, the advantages of the present invention are:
[0018] (1) The catalyst prepared by the present invention using a simple physical mixing method is more efficient than pure phase Mn 2 O 3 The catalyst has better low-temperature performance and excellent resistance to ammonium nitrate precipitation.
[0019] (2) The MnAl catalyst prepared by the present invention is heated to NH 3 -It exhibits excellent low-temperature (150°C) catalytic performance in SCR, and has excellent resistance to ammonium nitrate precipitation. The catalyst is stable and has high catalytic activity.
[0020] (3) The preparation method of the present invention is simple, convenient, environmentally friendly, and has no secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is the XRD result diagram of the MnAl catalyst prepared by the present invention;
[0022] Figure 2 The H of the MnAl catalyst prepared in the present invention is 2 -TPR result graph;
[0023] Figure 3 The NO of the MnAl catalyst prepared in the present invention is x Conversion rate results chart;
[0024] Figure 4 The relative NO of the MnAl catalyst prepared in this invention is x Conversion rate results chart;
[0025] Figure 5 The NO of different proportions of MnAl catalysts prepared in this invention x Conversion rate results chart;
[0026] Figure 6 The NO of the series of MnAl catalysts prepared by the present invention x Conversion rate results graph. DETAILED DESCRIPTION
[0027] The present invention is further described below in conjunction with specific embodiments.
[0028] The Mn used in the following examples 2 O 3 and Mn 2 O 3 -1 comes from Shanghai BiDe Pharmaceutical Technology Co., Ltd., with purity of 99.1% and 98.5% (mass fraction) respectively; Mn 2 O 3 -2Source: Shanghai MacLean Biochemical Technology Co., Ltd.; Al 2 O3 -1Source: Shanghai Hushi Laboratory Equipment Co., Ltd.; Al 2 O 3 -2 Source: Xuancheng Jingrui New Materials Co., Ltd., model number: VK-L20Y;
[0029] Example 1
[0030] 1. The preparation method of MnAl catalyst is as follows:
[0031] Mn 2 O 3 Put it in a mortar and grind it for 30 minutes. After grinding, put it in an oven and dry it at 100℃ for 2 hours. Then, 2 O 3 With γ-Al 2 O 3 (Al 2 O 3 -2) The mixture was ground into a mortar at a mass ratio of 1:1 for 30 min, and then dried in an oven at 100°C for 2 h to prepare a MnAl catalyst. The MnAl catalyst was characterized, and the results are as follows Figure 1 , 2 shown.
[0032] Figure 1 This is the XRD result diagram of the MnAl catalyst prepared in the present invention; as can be seen from the figure, Mn 2 O 3 The crystal form did not change and remained in the ferromanganese phase.
[0033] Figure 2 The H of the MnAl catalyst prepared in the present invention is 2 -TPR result diagram; As can be seen from the figure, Al 2 O 3 After the introduction of Mn 2 O 3 Changes in the Mn-O structure.
[0034] 2. The MnAl catalyst prepared in Example 1 was applied to NH 3 -SCR reaction, the specific test method is as follows: The catalytic activity test is carried out in a fixed bed continuous flow quartz reactor. The catalyst particle size is 40-60 mesh, and the dosage is 100 mg. The reaction gas composition is: 500 ppm NO, 500 ppm NH 3 , 4% O 2 , Ar was used as the balance gas, and the gas space velocity in the reaction was 60000 mL·g -1 ·h -1Before the reaction, the catalyst was purged with high-purity Ar at 200°C for 0.5 h. The catalytic reaction was carried out at 60-270°C, and the activity data was collected after the reaction reached equilibrium. The product was detected and analyzed by a Thermofisher IS10 infrared spectrometer. x The conversion rate is calculated using the following formula:
[0035]
[0036] Where, [NOx] in is the NOx inlet concentration, [NOx] out is the NOx outlet concentration, and the result is as follows Figure 3 And as shown in Table 1.
[0037] Table 1Mn 2 O 3 Reaction temperature and conversion rate of MnAl samples
[0038]
[0039]
[0040] Figure 3 The NO of the MnAl catalyst prepared in the present invention is x Conversion rate results; Table 1 is Mn 2 O 3 The reaction temperature and conversion rate of MnAl samples are given by Figure 3 As shown in Table 1, compared with pure Mn 2 O 3 In comparison, the low-temperature denitrification performance of the MnAl mixed oxide catalyst is significantly improved.
[0041] 3. The reaction stability test of MnAl catalyst was carried out. The test results were the same as those of catalytic activity test, except that the test temperature was changed to 150°C. The reaction stability was measured by comparing the transient NO x The conversion rate is calculated as a percentage of the initial value. The specific formula is as follows:
[0042]
[0043] Where X is the instantaneous NOx conversion rate, X 0 is the initial NOx conversion rate, and the results are as follows Figure 4 shown.
[0044] Figure 4 The relative NO of the MnAl catalyst prepared in this invention is x Conversion rate results; As can be seen from the figure, Mn 2 O 3 Poor reaction stability, mixed Al 2 O3 After that, the reaction stability was significantly improved.
[0045] Example 2
[0046] The MnAl catalyst was prepared according to the method of Example 1, except that Mn 2 O 3 and Al 2 O 3 The mass ratio of NH 3 -SCR reaction, the specific test method is as shown in Example 1, only the catalytic reaction temperature is changed to 60-240°C, the results are as follows Figure 5 And as shown in Table 2.
[0047] Table 2 Reaction temperature and conversion rate of MnAl catalysts with different ratios
[0048]
[0049]
[0050] Figure 5 The NO of different proportions of MnAl catalysts prepared in this invention x The conversion rate results are shown in Table 2. The reaction temperature and conversion rate of MnAl catalysts with different ratios are shown in Table 2. Figure 5 As shown in Table 2, with the increase of Mn 2 O 3 With the increase of MnAl content, the low-temperature denitrification performance of MnAl mixed oxide catalyst is improved.
[0051] Example 3
[0052] Samples MnAl-1 and MnAl-2 were prepared according to the method of Example 1, wherein the raw materials for preparing MnAl-1 were Mn and 2 O 3 -1 and Al 2 O 3 -1, MnAl-2 is prepared by mixing Mn in a mass ratio of 1:1. 2 O 3 -2 and Al 2 O 3 -2, applying the catalyst to NH 3 -SCR reaction, the specific test method is as shown in Example 1, and the results are as follows Figure 6 And as shown in Table 3.
[0053] Table 3 Series MnAl and Mn 2 O 3 Reaction temperature and conversion rate
[0054]
[0055] Figure 6 For the series MnAl and Mn 2 O 3 Catalyst NO x The conversion rate results are shown in Table 3 for the series MnAl and Mn 2 O 3 The reaction temperature and conversion rate are given by Figure 6 As shown in Table 3, Al 2 O 3 Introducing Mn 2 O 3 The improvement of low-temperature denitrification performance is universal.
Claims
1. A low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition, characterized in that: The preparation method of the catalyst comprises the following steps: drying the ground Mn2O3, mixing and grinding the ground Mn2O3 with γ-Al2O3, and drying the mixture to obtain a MnAl catalyst, namely, a low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition.
2. A method for preparing a low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition, characterized in that: The ground Mn2O3 is dried, mixed with γ-Al2O3, and the mixture is dried to obtain a MnAl catalyst, i.e., a low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition; the mass ratio of the Mn2O3 to the γ-Al2O3 is 1:
1.
3. The method for preparing the low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition according to claim 2, characterized in that: The ground Mn2O3 was dried at 100°C for 2h.
4. The method for preparing the low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition according to claim 2, characterized in that: The mixture was dried at a temperature of 100°C.
5. The method for preparing the low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition according to claim 2, characterized in that: The mixture was dried for 2 h.
6. The method for preparing the low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition according to claim 2, characterized in that: The time for mixing and grinding the Mn2O3 and γ-Al2O3 is 30 minutes.
7. Use of the low-temperature NH3-SCR catalyst resistant to ammonium nitrate deposition according to claim 1 in flue gas denitrification in non-power industries.
8. The use according to claim 7, characterized in that: The catalytic conditions for flue gas denitrification in the non-electricity industry are: the catalyst particle size is 40-60 mesh, the reaction gas composition is 500ppm NO, 500ppm NH3 and 4% O2, Ar is used as the balance gas, and the gas space velocity in the reaction is 60000mL·g -1 ·h -1 .
9. The use according to claim 8, characterized in that: The catalyst was purged with high-purity Ar at 200° C. for 0.5 h before the reaction.
10. The use according to claim 8, characterized in that: The temperature of the catalytic reaction is 60-270°C.