Ferromanganese-based NH3-SCR (Selective Catalytic Reduction) denitration catalyst as well as preparation method and application thereof

Abstract

The invention provides a ferromanganese-based NH3-SCR (selective catalytic reduction) denitration catalyst as well as a preparation method and application thereof. The ferromanganese-based NH3-SCR denitration catalyst is obtained through a reaction of Mn salt, Fe salt and Pr salt. The molar ratio of Mn to Fe is (1: 0.69)-(1: 0.71); and the molar ratio of Mn to Pr is (1: 0.05)-(1: 0.25). The preparation method of the ferromanganese-based NH3-SCR denitration catalyst comprises the following steps: providing Mn salt, Fe salt and Pr salt; wherein the molar ratio of Mn to Fe is (1: 0.69) to (1: 0.71); the molar ratio of Mn to Pr is (1: 0.05)-(1: 0.25); the Mn salt, the Fe salt and the Pr salt are subjected to a reaction, and the ferromanganese-based NH3-SCR denitration catalyst is obtained. In flue gas denitration, the catalyst has good sulfur resistance and water resistance and excellent low-temperature catalytic activity.

Description

Technical Field

[0001] The present application relates to waste gas treatment technology and environmental catalytic environmental technology, and in particular to a manganese iron-based NH3-SCR denitrification catalyst, a preparation method thereof, and applications thereof. Background Art

[0002] With the acceleration of urbanization and the rapid development of industry and manufacturing, the petrochemical industry will lead to the emission of nitrogen oxides during the production process and incomplete combustion process. The use of NH3 selective catalytic reduction (NH3-SCR) technology is the most mature denitrification technology in the field of denitrification. Currently, the SCR system has been used to reduce the emission of nitrogen oxides (NO x ).

[0003] NH3-SCR technology uses NH3 selective catalytic reduction (NH3-SCR) technology to remove NO x High efficiency and stable operation, it is the most promising NO x Purification technology. During the entire NH3-SCR process, under the action of the catalyst, the NO is selectively converted to x Reduction to N2 is the core of the entire technology. The development of NH3-SCR catalysts with excellent activity is currently a hot topic of research.

[0004] In the related art, NH3-SCR catalysts have the problem of insufficient sulfur resistance and water resistance at low temperatures. Summary of the Invention

[0005] In view of this, the purpose of this application is to propose a manganese-iron based NH3-SCR denitrification catalyst, its preparation method and application.

[0006] Based on the above-mentioned purpose, the present application provides a manganese-iron-based NH3-SCR denitrification catalyst, which is obtained by reacting Mn salt, Fe salt and Pr salt; wherein Mn is an active component, Fe and Pr are auxiliary components; the molar ratio of Mn to Fe is (1:0.69) to (1:0.71); the molar ratio of Mn to Pr is (1:0.05) to (1:0.25).

[0007] In some embodiments, the manganese-iron based NH3-SCR denitration catalyst is in an amorphous state; Mn and Fe exist in the form of a complex; the manganese-iron based NH3-SCR denitration catalyst is prepared by a hot solvent method, a coprecipitation method, or a sol-gel method.

[0008] In some embodiments, the manganese-iron based NH3-SCR denitration catalyst is prepared by a hot solvent method; the reaction temperature of the Mn salt, the Fe salt and the Pr salt is 178-182° C., and the reaction time is 1-12 h.

[0009] In some embodiments, the calcination temperature of the hot solvent method is 300-450°C.

[0010] The present application also provides a method for preparing a manganese-iron-based NH3-SCR denitration catalyst, comprising:

[0011] Providing Mn salt, Fe salt and Pr salt; wherein the molar ratio of Mn to Fe is (1:0.69) to (1:0.71); the molar ratio of Mn to Pr is (1:0.05) to (1:0.25);

[0012] The Mn salt, Fe salt and Pr salt are reacted to obtain the manganese-iron based NH3-SCR denitration catalyst.

[0013] In some embodiments, the manganese-iron based NH3-SCR denitration catalyst is prepared by a hot solvent method, a co-precipitation method or a sol-gel method.

[0014] In some of these embodiments, the manganese-iron based NH3-SCR denitration catalyst is prepared by a hot solvent method;

[0015] The step of reacting the Mn salt, the Fe salt, and the Pr salt to obtain the manganese-iron-based NH3-SCR denitration catalyst comprises: reacting the Mn salt, the Fe salt, and the Pr salt in a mixed solvent; wherein the reaction temperature is 178-182° C., and the reaction time is 1-12 hours;

[0016] The reaction product is calcined to obtain the manganese-iron based NH3-SCR denitration catalyst; wherein the calcination temperature is 300-450°C.

[0017] In some embodiments, the step of calcining the reactants further comprises: drying and grinding the reactants;

[0018] The reaction time is 2.8-3.2 hours; the calcination temperature is 398-402° C., and the calcination time is 1.8 to 2.2 hours; the molar ratio of Mn to Fe is (1:0.69) to (1:0.71); and the molar ratio of Mn to Pr is (1:0.099) to (1:0.11).

[0019] An embodiment of the present application also provides an application of a manganese-iron-based NH3-SCR denitration catalyst as described in any of the previous embodiments, or a manganese-iron-based NH3-SCR denitration catalyst prepared by the preparation method of the manganese-iron-based NH3-SCR denitration catalyst as described in any of the previous embodiments, in flue gas denitration; the flue gas includes nitrogen oxides.

[0020] In some embodiments, the flue gas also includes sulfide and water vapor.

[0021] The manganese-iron-based NH3-SCR denitrification catalyst provided in the embodiment of the present application is a Pr-modified MnFe-based catalyst. It has excellent sulfur resistance and water resistance in the NH3-SCR denitrification process and is easy to adapt to the complex environment of industrial flue gas. It has excellent low-temperature catalytic activity and NO x The conversion rate reaches 95%. The MnFe-based catalyst can be prepared using a hot solvent method, which has the advantages of simple preparation method, low cost, easy control, and suitability for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in this application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are merely embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is the X-ray diffraction pattern (XRD) of the catalyst sample in Example 1.

[0024] Figure 2 This is the X-ray diffraction pattern (XRD) of the catalyst sample of Comparative Example 1.

[0025] Figure 3 These are the catalytic activity test diagrams prepared in Example 2, Example 3, Example 4, and Example 5.

[0026] Figure 4 These are the catalytic activity test diagrams prepared in Example 1, Example 6, Example 7, and Example 8.

[0027] Figure 5 These are the catalytic activity test diagrams prepared for Example 1, Example 8, Example 9, Example 10, Example 11, and Example 12.

[0028] Figure 6 These are the catalytic activity test graphs prepared in Example 1, Comparative Example 1, and Comparative Example 2.

[0029] Figure 7These are the catalytic activity test diagrams prepared in Example 1, Example 13, Example 14, Example 15, and Example 16.

[0030] Figure 8 These are the catalytic activity test diagrams prepared in Example 1, Example 17, Example 18, and Example 19.

[0031] Figure 9 This is a sulfur resistance test chart showing the change in activity of the catalysts prepared in Example 1 and Comparative Example 1 over time after adding SO2.

[0032] Figure 10 This is a sulfur resistance test chart showing the change in activity of the catalysts prepared in Example 1 and Comparative Example 1 over time after adding H2O.

[0033] Figure 11 This is a sulfur resistance test chart showing the change in activity of the catalysts prepared in Example 1 and Comparative Example 1 over time after adding H2O and SO2. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of this application more clear, this application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0035] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meanings understood by persons having ordinary skills in the field to which this application belongs. The words "include" or "comprise" and the like used in the embodiments of this application mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, but do not exclude other elements or objects.

[0036] Currently, commercially available NH3-SCR catalysts primarily include vanadium-based V2O5-WO3 / TiO2 or V2O5-MoO3 / TiO2 catalysts. These catalysts have disadvantages such as a narrow operating temperature range, applicable only to temperatures between 300 and 400°C, and low N2 selectivity at low temperatures (e.g., below 200°C) or high temperatures (e.g., above 400°C). The flue gas temperature window in some steel mills, cement plants, and glass plants is relatively low (e.g., temperatures <250°C). Consequently, vanadium-based catalysts are becoming less suitable for existing industrial conditions. Furthermore, at low temperatures, sulfides in the flue gas readily react to form ammonium sulfate and metal sulfates, clogging the pores of the vanadium-based catalyst, blocking or even destroying the active sites. At high temperatures, vanadium species may further volatilize, leading to secondary pollution. Consequently, vanadium-based catalysts suffer from low activity at low temperatures and poor sulfur resistance.

[0037] Commercially available NH3-SCR catalysts also include molecular sieve catalysts. Currently, the main molecular sieve catalyst is Cu-SSZ-13, which offers a wide temperature window and hydrothermal stability. However, its conversion rate and sulfur resistance at low temperatures still cannot achieve high activity.

[0038] Metal oxide catalysts commonly use transition metals as their metal source. Mn-based catalysts are considered promising catalysts for low-temperature NH3-SCR reactions. However, Mn-based catalysts alone suffer from poor hydrothermal stability and resistance to sulfur and water. Current research focuses on improving thermal stability, surface acidity, and redox activity by modifying or doping with various metals to produce low-cost catalysts with excellent low-temperature performance.

[0039] Therefore, existing catalysts have the problems of low activity and poor sulfur resistance in low temperature environments; or poor sulfur resistance and water resistance in low temperature environments.

[0040] Based on this, the embodiment of the present application provides a novel method for producing a high-efficiency NO x The manganese-iron-based NH3-SCR catalyst with high removal efficiency and N2 selectivity is prepared by using a manganese (Mn) iron (Fe) mixed metal oxide catalyst as the active component and praseodymium (Pr) as an auxiliary agent. It can meet the service conditions such as industrial tail gas removal. In addition, it can suppress the deactivation caused by the adsorption of trace amounts of SO2 and H2O mixed in the flue gas on the catalyst surface. The preparation method adopts the hot solvent method, which has the advantages of simple preparation process, low cost, and easy industrial production. It can solve to a certain extent the problems of existing catalysts having low activity and poor sulfur resistance in low temperature environments; or poor sulfur resistance and water resistance in low temperature environments.

[0041] The manganese iron based NH3-SCR denitration catalyst provided in the embodiment of the present application can be of the molecular formula MnFePrO x The manganese-iron-based NH3-SCR denitrification catalyst can be obtained by reacting a Mn salt, an Fe salt, and a Pr salt. Mn is the active component, and Fe and Pr are additive components. The molar ratio of Mn to Fe is (1:0.5) to (1:0.8), and the molar ratio of Mn to Pr is (1:0.05) to (1:0.25).

[0042] In some embodiments, the molar ratio of Mn to Fe can be (1:0.69) to (1:0.71), and the molar ratio of Mn to Pr can be (1:0.05) to (1:0.25). For example, the molar ratio of Mn to Fe can be 1:0.69, 1:0.7 or 1:0.71. The molar ratio of Mn to Pr can be 1:0.05, 1:0.075, 1:0.1, 1:0.125, 1:0.15, 1:0.175, 1:0.2 or 1:0.25. In this way, the manganese iron-based NH3-SCR denitrification catalyst has a NOx reduction of 1:0.05, 1:0.075, 1:0.1, 1:0.125, 1:0.15, 1:0.175, 1:0.2 or 1:0.25 at 120 to 240 ° C. x The conversion rate of NO is above 95%. x The conversion rate is close to 100%.

[0043] In some embodiments, the manganese iron based NH3-SCR denitration catalyst is in an amorphous state, and the spectrum can be as follows: Figure 1 As shown. Wherein, Mn and Fe exist in the form of a complex. The manganese iron based NH3-SCR denitration catalyst can be prepared by a hot solvent method. Wherein, the manganese iron based NH3-SCR denitration catalyst MnFePrO prepared by the hot melt method x , XRD analysis results are as follows Figure 1 As shown in the figure, there is no obvious diffraction peak in the spectrum, indicating that the catalyst is in an amorphous state. The peak at 30° to 40° is mainly in the form of a complex of Mn and Fe. Generally, the stronger the interaction force, the lower the peak formed in the spectrum. It can be seen that the catalyst MnFePrO prepared by the hot solvent method x The interaction between the amorphous products formed is strong.

[0044] In some embodiments, the ferromanganese-based NH3-SCR denitration catalyst can be prepared by a hot solvent method. The ferromanganese-based NH3-SCR denitration catalyst obtained by the hot solvent method has a NO x The conversion rate can reach more than 95%. In the hot solvent method, the reaction temperature of Mn salt, Fe salt and Pr salt can be 178-182°C and the reaction time can be 1-12 hours. For example, the reaction temperature can be 178°C, 179°C, 180°C or 181°C. The reaction time can be 1h, 1.5h, 2.8h, 2.9h, 3.0h, 3.1h, 3.2h, 4.5h, 6h, 7.5h, 9h, 10.5h or 12h. During calcination, the calcination temperature can be 300-450°C, for example, 300°C, 325°C, 350°C, 375°C, 400°C, 425°C or 450°C. The calcination time can be 1.8-2.2h. For example, it can be 1.8h, 1.9h, 2.0h, 2.1h or 2.2h.

[0045] The manganese-iron-based NH3-SCR denitrification catalyst provided in the embodiment of the present application is a Pr-modified MnFe-based catalyst. It has excellent sulfur resistance and water resistance in the NH3-SCR denitrification process and is easy to adapt to the complex environment of industrial flue gas. It has excellent low-temperature catalytic activity and NO x The conversion rate reaches 95%. The MnFe-based catalyst can be prepared using a hot solvent method, which has the advantages of simple preparation method, low cost, easy control, and suitability for industrial production.

[0046] Based on the same inventive concept, corresponding to the ferromanganese-based NH3-SCR denitration catalyst of any of the above embodiments, the embodiment of the present application further provides a method for preparing the ferromanganese-based NH3-SCR denitration catalyst.

[0047] The preparation method of a manganese iron-based NH3-SCR denitration catalyst provided in an embodiment of the present application may include:

[0048] S100, providing a Mn salt, an Fe salt, and a Pr salt; wherein the molar ratio of Mn to Fe is (1:0.5) to (1:0.8); and the molar ratio of Mn to Pr is (1:0.05) to (1:0.25);

[0049] S200, reacting the Mn salt, Fe salt and Pr salt to obtain the manganese-iron based NH3-SCR denitration catalyst.

[0050] In some embodiments, in step S100, the Mn salt may be Mn(NO3)2 or Mn(CH3COO)2, etc. The Fe salt may be Fe(NO3)2 or Fe(CH3COO)3, etc. The Pr salt may be Pr(NO3)2, etc.

[0051] In some embodiments, in step S200, the manganese-iron-based NH3-SCR denitration catalyst can be prepared by a hot solvent method. The reacting of the Mn salt, Fe salt, and Pr salt can include: reacting by a hot solvent method. Generally, before reacting the Mn salt, Fe salt, and Pr salt, the step can also include: providing a mixed solvent. The mixed solvent can be a mixture of isopropyl alcohol and glycerol. Typically, the mixed solvent can be uniformly stirred. The volume ratio of isopropyl alcohol to glycerol can be 4.9 to 5.1:1, for example, 4.9:1, 5:1, or 5.1:1.

[0052] In some embodiments, reacting the Mn salt, Fe salt and Pr salt to obtain the manganese-iron-based NH3-SCR denitrification catalyst may include: reacting the Mn salt, Fe salt and Pr salt in a mixed solvent; wherein the reaction temperature is 178-182°C and the reaction time is 1-12 hours.

[0053] The reaction product is calcined to obtain the manganese-iron based NH3-SCR denitration catalyst; wherein the calcination temperature can be 300 to 450° C., and the calcination time can be 1.8 to 2.2 hours.

[0054] In some embodiments, the reaction time may be 2.8-3.2 hours, and the calcination temperature may be 398-402°C.

[0055] In some embodiments, the process may further include drying and grinding the reactants before calcining the reactants.

[0056] The manganese iron-based NH3-SCR denitration catalyst obtained by the above-mentioned hot solvent method has a wide activity range. Experimental data show that the conversion rate reaches more than 95% between 90°C and 300°C.

[0057] Based on the same inventive concept, embodiments of the present application also provide the use of the ferromanganese-based NH3-SCR denitration catalyst described in any of the above technical solutions, or the ferromanganese-based NH3-SCR denitration catalyst prepared by the method for preparing the ferromanganese-based NH3-SCR denitration catalyst described in the above technical solutions, in flue gas denitration. Typically, the flue gas contains nitrogen oxides. During the reaction, ammonia (NH3) is typically introduced as a reducing agent, and oxygen is also required.

[0058] In some embodiments, the flue gas also includes sulfide and water vapor.

[0059] The technical solution of the present invention is further described below with reference to specific implementation methods.

[0060] The experimental methods in the following examples are conventional methods unless otherwise specified.

[0061] Unless otherwise specified, the test materials used in the following examples were purchased from conventional biochemical reagent stores.

[0062] Example 1 Preparation of MnFePrO by hot solvent method x catalyst

[0063] Measure 80mL of isopropanol and 16mL of glycerol and stir to mix at 25°C. Weigh 0.232mL of Mn(NO3)2 solution, 0.2828g of Fe(NO3)3·9H2O, and 0.0435g of Pr(NO3)3·6H2O to the mixed solvent and stir for 30 minutes. Then place it in a polytetrafluoroethylene-lined container and react in an oven at 180°C for 3 hours. After cooling, wash it several times with ethanol, dry it in an oven at 60°C overnight, grind it, and calcine it in a muffle furnace at 400°C for 2 hours. The resulting sample is pressed into a tablet at a pressure of 10-20 MPa and crushed to 60-80 mesh size to obtain MnFePrO with a MnFePr ratio of 1:0.7:0.1. x Catalyst, defined as MnFePr 0.1 O x Example 1 Preparation of MnFePrO x The XRD analysis results of the catalyst can be shown as Figure 1 shown.

[0064] Example 2 Preparation of MnFe-based catalysts with different Mn:Fe ratios by hot solvent method

[0065] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3) 2 solution and 0.202 g of Fe (NO 3) 3·9H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60 ° C overnight, ground and placed in a muffle furnace for calcination at 400 ° C for 2 hours to obtain a MnFe-based catalyst, defined as MnFe 0.5 O x .

[0066] Example 3 Preparation of MnFe-based catalysts with different Mn:Fe ratios by hot solvent method

[0067] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3) 2 solution and 0.2424 g of Fe (NO 3) 3·9H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed with ethanol several times, dried in an oven at 60 ° C overnight, ground and placed in a muffle furnace for calcination at 400 ° C for 2 hours to obtain a MnFe-based catalyst, defined as MnFe 0.6 O x .

[0068] Example 4 Preparation of MnFe-based catalysts with different Mn:Fe ratios by hot solvent method

[0069] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3) 2 solution and 0.2828 g of Fe (NO 3) 3·9H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed with ethanol several times, dried in an oven at 60 ° C overnight, ground and placed in a muffle furnace for calcination at 400 ° C for 2 hours to obtain a MnFe-based catalyst, defined as MnFe 0.7 O x .

[0070] Example 5 Preparation of MnFe-based catalysts with different Mn:Fe ratios by hot solvent method

[0071] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3) 2 solution and 0.3232 g of Fe (NO 3) 3·9H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed with ethanol several times, dried in an oven at 60 ° C overnight, ground and placed in a muffle furnace for calcination at 400 ° C for 2 hours to obtain a MnFe-based catalyst, defined as MnFe 0.8 O x .

[0072] Example 6 Preparation of MnO by Thermal Solvent Method x Catalyst

[0073] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix evenly. 0.29 mL of manganese nitrate solution was weighed and stirred for 30 minutes. Then, it was placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 400°C for 2 hours to produce MnO. x Catalyst, defined as MnO x .

[0074] Example 7 Preparation of FeO by Hot Solvent Method x Catalyst

[0075] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix evenly; 0.606 g of Fe(NO3)3·9H2O was weighed and stirred for 30 minutes, then placed in a polytetrafluoroethylene liner and reacted in an oven at 180°C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 400°C for 2 hours to obtain FeO x Catalyst, defined as FeO x .

[0076] Example 8 Preparation of PrO by Hot Solvent Method x Catalyst

[0077] Compared with Example 1, the difference is that the catalyst is prepared by adding a separate component of the Pr metal source, and the other processes are the same as Example 1. The specific steps are as follows: 80 mL of isopropanol and 16 mL of glycerol are weighed and stirred at 25 ° C to mix evenly; 0.6525 g of Pr(NO3)3·6H2O is weighed and stirred for 30 minutes, then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it is washed several times with ethanol, dried in an oven at 60 ° C overnight, ground and calcined in a muffle furnace at 400 ° C for 2 hours to obtain PrO x catalyst.

[0078] Example 9 Preparation of MnFePrO with different Pr contents by hot solvent method x catalyst

[0079] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3 ) 2 solution, 0.2828 g of Fe (NO 3 ) 3 · 9H 2 O and 0.0217 g of Pr (NO 3 ) 3 · 6H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60 ° C overnight, ground and calcined in a muffle furnace at 400 ° C for 2 hours to obtain MnFePrO x Catalyst, defined as MnFePr 0.05 O x .

[0080] Example 10 Preparation of MnFePrO with different Pr contents by hot solvent method x catalyst

[0081] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3 ) 2 solution, 0.2828 g of Fe (NO 3 ) 3 · 9H 2 O and 0.0652 g of Pr (NO 3 ) 3 · 6H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60 ° C overnight, ground and calcined in a muffle furnace at 400 ° C for 2 hours to obtain MnFePrO x Catalyst, defined as MnFePr 0.15 O x .

[0082] Example 11 Preparation of MnFePrO with different Pr contents by hot solvent methodx catalyst

[0083] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3 ) 2 solution, 0.2828 g of Fe (NO 3 ) 3 · 9H 2 O and 0.087 g of Pr (NO 3 ) 3 · 6H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60 ° C overnight, ground and calcined in a muffle furnace at 400 ° C for 2 hours to obtain MnFePrO x Catalyst, defined as MnFePr 0.2 O x .

[0084] Example 12 Preparation of MnFePrO with different Pr contents by hot solvent method x catalyst

[0085] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn (NO 3 ) 2 solution, 0.2828 g of Fe (NO 3 ) 3 · 9H 2 O and 0.1087 g of Pr (NO 3 ) 3 · 6H 2 O were weighed and added to the above mixed solvent, stirred for 30 minutes, and then placed in a polytetrafluoroethylene liner and reacted in an oven at 180 ° C for 3 hours. After cooling, it was washed several times with ethanol, dried in an oven at 60 ° C overnight, ground and calcined in a muffle furnace at 400 ° C for 2 hours to obtain MnFePrO x Catalyst, defined as MnFePr 0.25 O x .

[0086] Example 13 Preparation of MnFePrO by hot solvent method with different reaction times x catalyst

[0087] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 1 hour. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 400°C for 2 hours to obtain a catalyst with a hot solvent reaction time of 1 hour, defined as MnFePrO x -ST-t-1h.

[0088] Example 14 Preparation of MnFePrO by hot solvent method with different reaction timesx catalyst

[0089] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 6 hours. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 400°C for 2 hours to obtain a catalyst with a hot solvent reaction time of 6 hours, defined as MnFePrO x -ST-t-6h.

[0090] Example 15 Preparation of MnFePrO by hot solvent method with different reaction times x catalyst

[0091] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 9 hours. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 400°C for 2 hours to obtain a catalyst with a hot solvent reaction time of 9 hours, defined as MnFePrO x -ST-t-9h.

[0092] Example 16 Preparation of MnFePrO by hot solvent method with different reaction times x catalyst

[0093] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 12 hours. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 400°C for 2 hours to obtain a catalyst with a hot solvent reaction time of 12 hours, defined as MnFePrO x -ST-t-12h.

[0094] Example 17 Preparation of MnFePrO by Hot Solvent Method at Different Calcination Temperatures x catalyst

[0095] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 3 hours. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 300°C for 2 hours to obtain a catalyst calcined at 300°C, defined as MnFePrO x -CT-300℃ catalyst.

[0096] Example 18 Preparation of MnFePrO by Hot Solvent Method at Different Calcination Temperatures x catalyst

[0097] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 3 hours. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 350°C for 2 hours to obtain a catalyst calcined at 350°C, defined as MnFePrO x -CT-350℃ catalyst.

[0098] Example 19 Preparation of MnFePrO by Hot Solvent Method at Different Calcination Temperatures x catalyst

[0099] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25°C to mix thoroughly. 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O, and 0.0435 g of Pr(NO3)3·9H2O were added to the above mixed solvent and stirred for 30 minutes. The mixture was then placed in a polytetrafluoroethylene-lined container and reacted in an oven at 180°C for 3 hours. After cooling, the mixture was washed several times with ethanol, dried in an oven at 60°C overnight, ground, and calcined in a muffle furnace at 450°C for 2 hours to obtain a catalyst calcined at 450°C, defined as MnFePrO x -CT-450℃ catalyst.

[0100] Comparative Example 1 Preparation of MnFePrO by coprecipitation x catalyst

[0101] 80 mL of isopropanol and 16 mL of glycerol were weighed and stirred at 25 ° C to mix evenly; 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O and 0.0435 g of Pr(NO3)3·6H2O were weighed and added to the above mixed solvent and stirred for 30 min. Then 0.55 mL of NH3·H2O was added and stirred for 3 h to obtain a precipitate, which was then washed with ethanol several times, dried in an oven at 60 ° C overnight, ground and calcined in a muffle furnace at 400 ° C for 2 h to obtain MnFePrO prepared by co-precipitation method. x Catalyst, defined as MnFePrO x -CP.

[0102] MnFePrO prepared in Comparative Example 1 x The XRD analysis results of the catalyst can be shown as Figure 2 See Figure 2 It can be seen that there is no obvious diffraction peak in the spectrum, indicating that the catalyst is in an amorphous state. The peaks at 20° to 30° are mainly in the form of Fe2O3, and between 30° and 40° are mainly in the form of Mn and Fe complexes. Generally, the stronger the interaction force, the lower the peak formed in the spectrum. It can be seen that the catalyst MnFePrO prepared by the coprecipitation method is x The interaction between Mn and Fe in the formed amorphous products is weak.

[0103] Comparative Example 2 Preparation of MnFePrO by Sol-Gel Method x catalyst

[0104] 100 mL of deionized water was measured and stirred at 25 ° C to mix evenly; 0.3456 g of citric acid was added and stirred for 30 min; 0.232 mL of Mn(NO3)2 solution, 0.2828 g of Fe(NO3)3·9H2O and 0.0435 g of Pr(NO3)3·6H2O were weighed and added to the above mixed solvent, and a translucent sol was formed under stirring at 70 ° C. Then, the mixture was continuously heated at 80 ° C to form a viscous gel; the gel was dried at 100 ° C to form a dry gel; the dry gel was ground and calcined in a muffle furnace at 400 ° C for 2 h to obtain MnFePrO prepared by the sol-gel method. x Catalyst, defined as MnFePrO x -SG catalyst.

[0105] Table 1 Composition of metal oxide catalysts in different examples

[0106]

[0107] Table 2 Preparation conditions of different metal oxide catalysts

[0108]

[0109]

[0110] Test Example 1 Testing the activity of MnFe-based catalysts with different Mn and Fe ratios

[0111] Experimental purpose: To test the different Mn, Fe ratios of MnFePrO x The effects of catalyst activity on the NO2 activity of MnFe-based catalysts with different Mn / Fe ratios prepared in Examples 2, 3, 4 and 5 were investigated in the temperature range of 90-330°C. x Test the conversion rate.

[0112] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The test temperature was recorded every 30°C, and each test temperature lasted for 20-40 minutes to ensure the stability of the measured value. x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the catalyst activity at different Mn:Fe ratios.

[0113] Experimental results: As shown in Table 3 and Figure 3 shown.

[0114] Result analysis: Figure 3 It can be seen that the MnFe-based catalysts with different Mn:Fe ratios prepared in Examples 2 to 5 all have a conversion rate of more than 95% at 120°C to 300°C. Among them, when the molar ratio of Mn to Fe is 1:0.7, the conversion rate of the MnFe catalyst can still reach 94.3% at a low temperature of 90°C. Therefore, the manganese iron oxide with this molar ratio is modified with Pr to prepare MnFePrO x catalyst.

[0115] Test Example 2 Testing the catalytic activity of single metal oxide catalysts with different compositions

[0116] Experimental purpose: To examine the effects of different metal components, Mn, Fe and Pr, on the x The effects of the catalyst activity on the NO in the temperature range of 90-330 ° C were investigated for the catalysts prepared in Example 1, Example 6, Example 7 and Example 8.x Test the conversion rate.

[0117] Table 3 Conversion rate of nitrides by different metal oxide catalysts as the temperature changes

[0118]

[0119] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The catalysts of Example 1, Example 6, Example 7, and Example 8 were tested for NO in the temperature range of 90-330 °C. x The conversion rate is tested, and each test temperature is recorded as a test temperature every 30℃, and each test temperature lasts for 20-40 minutes to ensure the stability of the measured value. x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures MnFePr 0.1 O x Compared with the catalytic activity of single metal oxide catalysts.

[0120] Experimental results: As shown in Table 3 and Figure 4 shown.

[0121] Result analysis: Figure 4 It can be seen that the NH3-SCR activities of different single metal oxide catalysts are different. x With MnFePr 0.1 O x The activity difference is small. At 90℃, both have a conversion rate of nearly 90%, while FeO x It starts to show a higher conversion rate at 210℃, PrO x It has a high NH3-SCR activity at around 270-300℃. x In the catalyst system, Mn is the active component, Fe and Pr exist in the form of co-catalysts, and improve the activity and stability of the catalyst.

[0122] Test Example 3: Verification of Catalytic Activity at Different Mn to Pr Molar Ratios

[0123] Experimental purpose: To verify the MnFePrO with different Mn to Pr molar ratios xThe activity of the catalyst was investigated. The MnFePrO prepared in Example 1, Example 9, Example 10, Example 11 and Example 12 were x The catalyst reacts with NO in the temperature range of 90-330℃. x Test the conversion rate.

[0124] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The catalysts of Example 1, Example 6, Example 7, and Example 8 were tested for NO in the temperature range of 90-330 °C. x The conversion rate is tested, and each test temperature is recorded as a test temperature every 30℃, and each test temperature lasts for 20-40 minutes to ensure the stability of the measured value. x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the catalyst MnFePrO with different Mn and Pr ratios. x activity.

[0125] Experimental results: As shown in Table 3 and Figure 5 shown.

[0126] Result analysis: Figure 5 It can be seen that the catalysts MnFePrO with different Mn and Pr ratios x All have high activity.

[0127] Test Example 4 Verification of MnFePrO prepared by different preparation methods x Catalyst activity

[0128] Experimental purpose: To verify the different preparation methods of MnFePrO x The activity of the catalyst was investigated by comparing the MnFePrO prepared in Example 1, Comparative Example 1 and Example 14. x The catalyst reacts with NO in the temperature range of 90-330℃. x Test the conversion rate.

[0129] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The catalysts of Example 1, Example 6, Example 7, and Example 8 were tested for NO in the temperature range of 90-330 °C. x The conversion rate is tested, and each test temperature is recorded as a test temperature every 30℃, and each test temperature lasts for 20-40 minutes to ensure the stability of the measured value. x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the MnFePrO obtained by different preparation methods. x Activity of the catalyst.

[0130] Experimental results: As shown in Table 3 and Figure 6 shown.

[0131] Result analysis: Figure 6 It can be seen that the MnFePrO obtained by different preparation methods x The catalyst has a conversion rate of more than 95% at 120-270 ° C. Among them, only the MnFePrO prepared by the hot solvent method has a conversion rate of more than 95%. x The conversion rate of the catalyst is still as high as 95% at 90℃. x The catalyst activity is different. Among them, MnFePrO prepared by hot melt method x The catalyst has the widest activity range.

[0132] Test Example 5 Verification of MnFePrO prepared by hot solvent method with different reaction times x Catalyst activity

[0133] Experimental purpose: To verify the thermal solvent method with different reaction times for the preparation of MnFePrO x The activity of the catalyst was investigated by comparing the MnFePrO prepared in Example 1, Example 13, Example 14, Example 15 and Example 16. x The catalyst reacts with NO in the temperature range of 90-330℃. x Test the conversion rate.

[0134] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The amount of catalyst used in the experiment was 0.2 g. The NO x The conversion rate is tested, and each test temperature is recorded as a test temperature every 30℃, and each test temperature lasts for 20-40 minutes to ensure the stability of the measured value. x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the MnFePrO prepared by the hot solvent method at different reaction times. x Activity of the catalyst.

[0135] Experimental results: As shown in Table 3 and Figure 7 shown.

[0136] Result analysis: Figure 7 It can be seen that the MnFePrO prepared by the hot solvent method with different reaction times x The catalyst has an activity of more than 95% at 120-270℃. x The catalyst has high activity.

[0137] Test Example 6 Verification of MnFePrO prepared by hot solvent method at different calcination temperatures x Catalyst activity

[0138] Experimental purpose: To verify the thermal solvent method of MnFePrO prepared at different calcination temperatures x The activity of the catalyst was investigated by comparing the MnFePrO prepared in Example 1, Example 17, Example 18 and Example 19. x The catalyst reacts with NO in the temperature range of 90-330℃. x Test the conversion rate.

[0139] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The catalysts of Example 1, Example 17, Example 18 and Example 19 were tested for NO in the temperature range of 90-330 °C. xThe conversion rate is tested, and each test temperature is recorded as a test temperature every 30℃, and each test temperature lasts for 20-40 minutes to ensure the stability of the measured value. x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the MnFePrO prepared by the hot solvent method at different calcination temperatures. x Activity of the catalyst.

[0140] Experimental results: As shown in Table 3 and Figure 8 shown.

[0141] Result analysis: Figure 8 It can be seen that the MnFePrO prepared by hot solvent method at different calcination temperatures x The catalyst has a NOx content of more than 95% at 150-250℃. x Therefore, the MnFePrO prepared by hot solvent method at different calcination temperatures x The catalyst has high activity.

[0142] Test Example 7 Verification of MnFePrO prepared by different preparation methods x Catalyst sulfur resistance

[0143] Experimental purpose: To verify the different preparation methods of MnFePrO x The activity of the catalyst was investigated by comparing the MnFePrO prepared in Example 1 and Comparative Example 1. x Catalyst, and MnFeO prepared in Example 4 x The catalyst is at 150℃. When NO x Test the conversion rate.

[0144] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The catalysts of Example 1, Example 4 and Comparative Example 1 were tested for their sulfur poisoning resistance at 150°C. The NO content in the tail gas (after removing NH3 and H2O) was x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the data, and records the test values ​​every 20 minutes. x The sulfur resistance of the catalyst, and MnFeOx sulfur resistance.

[0145] Experimental results: As shown in Table 3 and Figure 9 shown.

[0146] Result analysis: Figure 9 It can be seen that the MnFePrO obtained by different preparation methods x The catalyst has high sulfur resistance within 10 hours after SO2 is introduced, and the sulfur resistance is almost unchanged within 10 hours. x The activity began to decline after SO2 was introduced. After 10 h of SO2 introduction, the activity of NO x The conversion rate of MnFePrO obtained by different preparation methods is reduced to 69.3%. x The catalysts all have high sulfur resistance. It can be seen that Pr modification has a significant improvement on the sulfur resistance of manganese iron metal oxide catalysts.

[0147] Test Example 8 Testing of MnFePrO prepared by different preparation methods x Water resistance of catalyst

[0148] Experimental purpose: to test MnFePrO prepared by different methods x The activity of the catalyst was investigated by comparing the MnFePrO prepared in Example 1 and Comparative Example 1. x The catalyst is at 150℃. When NO x Test the conversion rate.

[0149] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The water resistance of the catalysts of Example 1 and Comparative Example 1 was tested at 150 ° C. The NO content in the tail gas (after removing NH3 and H2O) was x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the data, and records the test values ​​every 20 minutes. x Sulfur resistance of the catalyst.

[0150] Experimental results: As shown in Table 3 and Figure 10 shown.

[0151] Result analysis: Figure 10It can be seen that the MnFePrO obtained by different preparation methods x There are differences in the water resistance of the catalysts. After the introduction of 10 vol.% H2O, the MnFePrO prepared by the co-precipitation method x The conversion rate of the catalyst decreased rapidly to 68.2% within 1 hour and stabilized at around 60%. x The catalyst was not affected by H2O. Therefore, the MnFePrO prepared by the hot solvent method x The catalyst has good water resistance at low temperatures.

[0152] Test Example 9 Testing of MnFePrO prepared by different preparation methods x Catalyst's sulfur and water resistance

[0153] Experimental purpose: To investigate the MnFePrO prepared by different methods. x The activity of the catalyst was investigated by comparing the MnFePrO prepared in Example 1 and Comparative Example 1. x The catalyst is at 150℃. When NO x Test the conversion rate.

[0154] Experimental Method: Catalyst activity was evaluated in a custom-made fixed-bed reactor. The reactor consisted of an 8mm inner diameter, 80cm long quartz tube filled with quartz sand as a partition. The reaction temperature was measured by a thermocouple placed in the center of the reactor tube and controlled using a programmed temperature controller. Reaction gas: N2 was used as the balance gas. The gas flow rate was set to 200 mL / min. The catalyst dosage in the experiment was 0.2 g. The water resistance of the catalysts of Example 1 and Comparative Example 1 was tested at 150 ° C. The NO content in the tail gas (after removing NH3 and H2O) was x The volume fraction of NO was manufactured by Thermo Fisher Scientific x The flue gas analyzer collects and measures the data, and records the test values ​​every 20 minutes. x Catalyst's resistance to sulfur and water.

[0155] Experimental results: As shown in Table 3 and Figure 11 shown.

[0156] Result analysis: Figure 11 It can be seen that the MnFePrO obtained by different preparation methods x After the introduction of H2O and SO2, the catalyst showed different resistance to water and sulfur. xAfter the catalyst was simultaneously introduced with 0.005 vol.% SO2 and 10 vol.% H2O, the conversion rate dropped rapidly to 63% and finally stabilized at around 50%. x The conversion rate of the catalyst remained unchanged after 0.005 vol.% SO2 and 10 vol.% H2O were introduced simultaneously. x The catalyst is more easily deactivated by the combined action of H2O and SO2. x The catalyst has good water and sulfur resistance in an environment containing SO2 and H2O.

[0157] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples. Within the scope of the present disclosure, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present disclosure as described above, which are not provided in detail for the sake of simplicity.

[0158] While the disclosure has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0159] The embodiments of the present disclosure are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present disclosure should be included in the scope of protection of the present disclosure.

Claims

1. A manganese iron-based NH3-SCR denitration catalyst, characterized in that: The manganese-iron based NH3-SCR denitration catalyst is obtained by reacting Mn salt, Fe salt and Pr salt; wherein Mn is an active component, Fe and Pr are auxiliary components; the molar ratio of Mn to Fe is (1:0.69) to (1:0.71); the molar ratio of Mn to Pr is (1:0.05) to (1:0.25).

2. The ferromanganese-based NH3-SCR denitration catalyst according to claim 1, characterized in that: The manganese-iron based NH3-SCR denitration catalyst is in an amorphous state; Mn and Fe exist in the form of a complex.

3. The ferromanganese-based NH3-SCR denitration catalyst according to claim 2, characterized in that: The manganese-iron based NH3-SCR denitration catalyst is prepared by a hot solvent method; the reaction temperature of the Mn salt, the Fe salt and the Pr salt is 178-182° C., and the reaction time is 1-12 hours.

4. The manganese iron-based NH3-SCR denitration catalyst according to claim 3, characterized in that: The calcination temperature of the hot solvent method is 300-450°C.

5. A method for preparing a manganese-iron-based NH3-SCR denitration catalyst, characterized in that: include: Providing Mn salt, Fe salt and Pr salt; wherein the molar ratio of Mn to Fe is (1:0.69) to (1:0.71); the molar ratio of Mn to Pr is (1:0.05) to (1:0.25); The Mn salt, Fe salt and Pr salt are reacted to obtain the manganese-iron based NH3-SCR denitration catalyst.

6. The method for preparing the ferromanganese-based NH3-SCR denitration catalyst according to claim 5, characterized in that: The manganese iron-based NH3-SCR denitration catalyst is prepared by a hot solvent method.

7. The method for preparing the ferromanganese-based NH3-SCR denitration catalyst according to claim 6, characterized in that: The step of reacting the Mn salt, the Fe salt, and the Pr salt to obtain the manganese-iron-based NH3-SCR denitration catalyst comprises: reacting the Mn salt, the Fe salt, and the Pr salt in a mixed solvent; wherein the reaction temperature is 178-182° C., and the reaction time is 1-12 hours; The reaction product is calcined to obtain the manganese iron-based NH3-SCR denitration catalyst; wherein the calcination temperature is 300-450°C.

8. The method for preparing the ferromanganese-based NH3-SCR denitration catalyst according to claim 7, characterized in that: Before the reactants are subjected to the calcination treatment, the further step includes: drying and grinding the reactants; The reaction time is 2.8-3.2 hours; the calcination temperature is 398-402° C., and the calcination time is 1.8 to 2.2 hours; the molar ratio of Mn to Fe is (1:0.69) to (1:0.71); and the molar ratio of Mn to Pr is (1:0.099) to (1:0.11).

9. Use of the ferromanganese-based NH3-SCR denitration catalyst according to any one of claims 1 to 4 or the ferromanganese-based NH3-SCR denitration catalyst prepared by the preparation method of the ferromanganese-based NH3-SCR denitration catalyst according to any one of claims 5 to 8 in flue gas denitration; the flue gas includes nitrogen oxides.

10. The use according to claim 9, characterized in that The flue gas also includes sulfide and water vapor.

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