Preparation method and application of tin-manganese-cobalt composite low-temperature water-resistant denitration catalyst

Abstract

The application discloses a preparation method and application of a tin-manganese-cobalt composite low-temperature water-resistant denitration catalyst, and belongs to the technical field of environmental protection. A certain amount of tin tetrachloride pentahydrate, manganese nitrate solution, concentrated hydrochloric acid and cobalt nitrate hexahydrate are mixed and dissolved in water, ammonia water is slowly added until the precipitation is completed after uniform stirring, and a series of tin-doped manganese-cobalt composite oxide catalysts are prepared through filtration, washing, drying and calcination. x The application can be applied to the catalytic elimination of NOx in non-electricity industries. x The catalyst has excellent low-temperature NH3-SCR activity, high thermal stability and better water resistance at low temperature than existing manganese-cobalt catalysts, and has the advantages of simple preparation process, low energy consumption, large-scale production and potential industrial application prospect in the catalytic elimination of NOx at low temperature in non-electricity industries.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection technology and relates to a method for preparing a tin-manganese-cobalt composite oxide catalyst and its application in denitrification of water-containing flue gas at low temperature (125-180℃) in non-electric industries. Background Technology

[0002] To further reduce NO x For emissions, non-power industries generally use NH3-SCR technology, which uses NH3 as a reducing agent under the action of a catalyst to reduce NO in flue gas. x The gas is reduced to nitrogen (N2). Currently, the flue gas emission temperature in non-power industries is generally below 300℃, especially after wet desulfurization processes where the flue gas temperature is even lower. Commercial V2O5-WO3(MoO3) / TiO2 catalysts, due to their high operating temperatures, exhibit poor low-temperature denitrification performance. Furthermore, low-temperature flue gas often contains a certain amount of impurities (H2O), which reduces the denitrification performance of SCR catalysts. Therefore, developing high-performance, water-poisoning-resistant low-temperature denitrification catalysts is one of the important goals for SCR flue gas treatment in non-power industries.

[0003] This invention prepares a series of tin-doped manganese-cobalt composite oxide catalysts via an ammonia water droplet co-precipitation method. Compared with manganese-cobalt oxide catalysts prepared by the same method, these catalysts exhibit significantly improved low-temperature NH3-SCR and water resistance properties. Among them, Mn... 0.50 Co 0.50 Sn 0.03 O x The catalyst exhibits optimal performance. The Mn prepared by this method... 0.50 Co 0.50 Sn 0.03 O x The catalyst can achieve 100% NH3-SCR denitrification performance at a low temperature of 125℃. It has a wide temperature window, excellent water resistance, high thermal stability, simple and convenient preparation process, no special requirements for equipment, low energy consumption, and can be mass-produced. It meets the technical requirements of low temperature NH3-SCR in non-electric industries and has good application prospects. Summary of the Invention

[0004] The purpose of this invention is to provide a highly efficient method for preparing a tin-manganese-cobalt composite oxide catalyst and its application in low-temperature water-containing flue gas denitrification in non-electric industries.

[0005] The technical problems to be solved by the present invention are as follows: (1) providing a method for preparing the tin-manganese-cobalt composite oxide catalyst, and (2) providing the application of the tin-manganese-cobalt composite oxide catalyst in denitrification of water-containing flue gas at low temperature (125-180℃).

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing a tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst, utilizing tin-doped manganese-cobalt composite oxide Mn 0.50 Co 0.50 Sn y O x The specific steps are as follows:

[0008] (1) Dissolve SnCl4·5H2O in deionized water, add 50wt.% Mn(NO3)2 solution and stir, then slowly add a certain amount of concentrated hydrochloric acid and stir.

[0009] (2) Add Co(NO3)2·6H2O and an appropriate amount of deionized water and stir. Then, under vigorous stirring, slowly add an appropriate amount of 22-25 wt.% NH3·H2O until pH=10.

[0010] (3) After stirring again, filter the suspension to obtain a precipitate, wash it several times, and then dry it in an oven.

[0011] (4) Finally, the dried precipitate was placed in a muffle furnace and calcined to obtain Mn. 0.50 Co 0.50 Sn y O x catalyst.

[0012] Furthermore, in the preparation method of the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst, the molar ratio of manganese, cobalt and tin in the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst is 50:50:(0-10).

[0013] Furthermore, the preparation method of the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst involves dissolving 0.6311–2.1036 g of SnCl4·5H2O and adding 10.7370 g of Mn(NO3)2 (50 wt.%) solution.

[0014] Furthermore, in the preparation method of the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst, the added concentrated hydrochloric acid has a mass fraction of 36.0-38.0% and a volume of 9-11 mL.

[0015] Furthermore, in the preparation method of the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst, 8.7309g of Co(NO3)2·6H2O is added.

[0016] Furthermore, in the preparation method of the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst, the calcination temperature in the muffle furnace is 550℃ and the time is 5h.

[0017] Furthermore, the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst is prepared by any of the methods described above.

[0018] Furthermore, the aforementioned tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst is applied in low-temperature water-resistant denitrification in non-electric industries.

[0019] Furthermore, the Mn 0.50 Co 0.50 Sn y O x The application of catalysts in low-temperature water-resistant denitrification in non-power industries is as follows: In low-temperature (125-180℃) flue gas, ammonia is used as a reducing agent to remove NO from the flue gas. x By selecting nitrogen (N2) as the reducing agent, the NH3-SCR reaction achieves 100% efficiency in catalytically eliminating nitrogen oxides. Furthermore, the conversion efficiency of nitrogen oxides reaches 100% under flue gas with a moisture content of 5% at 150°C.

[0020] The Mn prepared in this invention 0.50 Co 0.50 Sn y O x The catalysts (y = 0, 0.03, 0.05, 0.10) were evaluated using X-ray diffraction (XRD), temperature-programmed reduction (H2-TPR), temperature-programmed desorption (NH3-TPD), and denitrification and water resistance performance testing (NH3-SCR reaction). The results are shown in the appendix. Figure 1-5 .

[0021] Compared with existing technologies, the advantages of this invention are:

[0022] (1) The provided tin-manganese-cobalt composite catalyst has excellent low-temperature denitrification performance. It can achieve 100% NH3-SCR reaction denitrification performance at 125℃, reducing the cost problem caused by flue gas reheating.

[0023] (2) The provided tin-manganese-cobalt composite catalyst has a wide temperature window, excellent water resistance and high thermal stability, and can be used in low-temperature water-containing flue gas denitrification in non-electric industries.

[0024] (3) The preparation method of the provided tin-manganese-cobalt composite catalyst is simple, fast, energy-efficient, and can be mass-produced. Attached Figure Description

[0025] Figure 1 For Mn 0.50 Co 0.50 Sn y O x XRD results for (y = 0, 0.03, 0.05, 0.10).

[0026] Figure 2 For Mn 0.50 Co 0.50 Sn y O xH2-TPR results for (y = 0, 0.03, 0.05, 0.10).

[0027] Figure 3 For Mn 0.50 Co 0.50 Sn y O x (y = 0, 0.03, 0.05, 0.10) NH3-TPD results of the catalyst.

[0028] Figure 4 For Mn 0.50 Co 0.50 Sn y O x (y = 0, 0.03, 0.05, 0.10) NO conversion rate of NH3-SCR reaction results for catalyst;

[0029] Figure 5 For Mn 0.50 Co 0.50 Sn y O x (y = 0, 0.03, 0.05, 0.10) NH3-SCR reaction results of catalyst at low temperature 150℃ NO conversion rate. Detailed Implementation

[0030] Example 1

[0031] Using tin-doped manganese-cobalt composite catalyst Mn 0.50 Co 0.50 Sn 0.03 O x .

[0032] The preparation method is as follows: 0.6311 g of SnCl4·5H2O is dissolved in 60-80 mL of deionized water and stirred for 10-20 min; 10.7370 g of Mn(NO3)2 (50 wt.%) solution is added to the above solution and stirred for 10-20 min; to inhibit the hydrolysis precipitation of SnCl4·5H2O, 9-11 mL of concentrated hydrochloric acid is slowly added and stirred for 10-20 min; 8.7309 g of Co(NO3)2·6H2O and deionized water are added to 120-130 mL and stirred for 3-4 h; then, under vigorous stirring, an appropriate amount of 22-25 wt.% NH3·H2O is slowly added until pH = 10; after stirring again for 3-4 h, the suspension is filtered, and the precipitate is washed several times with deionized water and ethanol, dried at 70-80℃ for 22-24 h, and calcined in air at 550℃ for 5 h to prepare Mn 0.50 Co 0.50 Sn 0.03 O x catalyst.

[0033] Example 2

[0034] Using tin-doped manganese-cobalt composite catalyst Mn 0.50 Co 0.50 Sn 0.05 O x .

[0035] The preparation method is as follows: 1.0518g SnCl4·5H2O is dissolved in 60-80mL of deionized water and stirred for 10-20min; 10.7370g of Mn(NO3)2 (50wt.%) solution is added to the above solution and stirred for 10-20min; 9-11mL of concentrated hydrochloric acid is slowly added and stirred for 10-20min; 8.7309g of Co(NO3)2·6H2O and deionized water are added to 120-130mL and stirred for 3-4h; then, under vigorous stirring, an appropriate amount of 22-25wt.% NH3·H2O is slowly added until pH=10; after stirring again for 3-4h, the suspension is filtered, and the precipitate is washed several times with deionized water and ethanol, dried at 70-80℃ for 22-24h, and calcined in air at 550℃ for 5h to prepare Mn. 0.50 Co 0.50 Sn 0.05 O x catalyst.

[0036] Example 3

[0037] Using tin-doped manganese-cobalt composite catalyst Mn 0.50 Co 0.50 Sn 0.10 O x .

[0038] The preparation method is as follows: 2.1036 g of SnCl4·5H2O is dissolved in 60–80 mL of deionized water and stirred for 10–20 min; 10.7370 g of Mn(NO3)2 (50 wt.%) solution is added to the above solution and stirred for 10–20 min; 9–11 mL of concentrated hydrochloric acid is slowly added and stirred for 10–20 min; 8.7309 g of Co(NO3)2·6H2O and deionized water are added to 120–130 mL and stirred for 3–4 h; then, under vigorous stirring, an appropriate amount of 22–25 wt.% NH3·H2O is slowly added until pH = 10; after stirring again for 3–4 h, the suspension is filtered, and the precipitate is washed several times with deionized water and ethanol, dried at 70–80 °C for 22–24 h, and calcined in air at 550 °C for 5 h to prepare Mn. 0.50 Co 0.50 Sn 0.10 O x catalyst.

[0039] Mn0.50 Co 0.50 Sn y O x The XRD of (y = 0, 0.03, 0.05, 0.10) is as follows: Figure 1 As shown in the figure, this embodiment has successfully prepared a tin-doped manganese-cobalt composite catalyst.

[0040] Example 4

[0041] The Mn prepared above 0.50 Co 0.50 Sn y O x (y = 0, 0.03, 0.05, 0.10) Catalysts are used in the NH3-SCR reaction. For example... Figure 2 Mn 0.50 Co 0.50 Sn y O x (y = 0.03, 0.05, 0.10) The reduction temperature of surface oxygen species in the catalyst shifts towards lower temperatures, Mn 0.50 Co 0.50 Sn y O x Its redox properties compared to Mn 0.50 Co 0.50 O x Significantly enhanced. (By) Figure 3 It can be seen that Mn 0.50 Co 0.50 Sn y O x (y = 0.03, 0.05, 0.10) The number of surface acidic sites on the catalyst increases, especially in the temperature range of 100–200 °C. The increased amount of L acid improves the catalyst's performance in medium- and low-temperature denitration reactions. After Sn doping, Mn 0.50 Co 0.50 Sn 0.03 O x The catalyst achieves 100% NH3-SCR denitrification performance at 125℃, while also exhibiting excellent water resistance up to 150℃. This demonstrates that Sn doping significantly enhances the catalytic performance.

[0042] Compared to existing manganese-cobalt denitrification catalysts, the catalyst provided in this invention exhibits NH3-SCR water resistance at lower temperatures. Mn 0.50 Co 0.50 Sn 0.03 O x It exhibits the best catalytic performance (NO conversion and low-temperature water resistance), as shown in the following results. Figure 4 and Figure 5 As shown.

[0043] The specific reaction conditions are as follows: the catalytic reaction test was carried out in a fixed-bed continuous flow quartz reactor; the catalyst particle size was 40-60 mesh, and the dosage was 100 mg; the reaction gas composition was: 500 ppm NO, 500 ppm NH3, 5% O2, 5% H2O (if used), with N2 as the balance gas, and the gas space velocity in the reaction was 60000 mL·g. –1 ·h –1 Before the reaction, the catalyst needs to be purged with high-purity N2 at 300℃ for 1 hour. The catalytic reaction is carried out at 50–300℃, and data are collected after the reaction reaches equilibrium.

[0044] The product was analyzed by Thermofisher IS10 FTIR, and the NO conversion rate can be calculated using the following formula:

[0045]

Claims

1. A method for preparing a tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst, characterized in that, The specific steps are as follows: (1) Dissolve SnCl4·5H2O in deionized water, add Mn(NO3)2 solution and stir, then add concentrated hydrochloric acid and stir; dissolve 0.6311g SnCl4·5H2O, add 10.7370g 50wt.% Mn(NO3)2 solution; the mass fraction of the added concentrated hydrochloric acid is 36.0~38.0%, and the volume is 9~11 mL; (2) Add 8.7309g Co(NO3)2·6H2O and deionized water and stir. Then, under vigorous stirring, slowly add an appropriate amount of 22~25wt.%NH3·H2O until pH=10. (3) After stirring again, filter the suspension to obtain a precipitate, wash it several times, and then dry it in an oven; (4) Finally, the dried precipitate is placed in a muffle furnace and calcined to obtain Mn. 0.50 Co 0.50 Sn 0.03 O x Catalyst; calcination in a muffle furnace at 550 °C for 5 h.

2. The tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst is prepared according to the preparation method of claim 1.

3. The application of the tin-manganese-cobalt composite low-temperature water-resistant denitrification catalyst according to claim 2 in low-temperature water-resistant denitrification in non-power industries, characterized in that, In low-temperature flue gas, ammonia is used as a reducing agent to remove NO from the flue gas. x When nitrogen (N2) is selected for reduction, the NH3-SCR reaction achieves 100% efficiency in catalytic elimination of nitrogen oxides. At the same time, the conversion efficiency of nitrogen oxides reaches 100% under flue gas with 5% water content at 150℃.

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