Zeolite ssz-39 supported catalysts, methods of making and using the same

Abstract

The application provides an SSZ-39 zeolite supported catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: dispersing a commercial H-SSZ-39 zeolite in water, adding an etching agent to obtain a mixture, wherein the etching agent is oxalic acid or citric acid; the mixture is reacted at a temperature of 70-85 DEG C, and the reaction time is 2-10 h; after the reaction is completed, the mixture is filtered, washed, and the filter cake is dried, ground and calcined at 480-550 DEG C to obtain the H-SSZ-39 zeolite etched by OA; In(NO3)3.xH2O is dissolved in water, H-SSZ-39 is added, and the mixture is stirred at a constant temperature of 80-90 DEG C for 8 h; the mixture is centrifuged, washed, dried and then calcined to obtain In / H-SSZ-39. The modified In / H-SSZ-39 zeolite catalyst obtained by the technical scheme has better denitration activity in the CH4-SCR reaction.

Description

Technical Field

[0001] This invention relates to the fields of catalyst preparation technology and environmental pollution control, and particularly to an SSZ-39 zeolite supported catalyst, its preparation method, and its application. Background Technology

[0002] Nitrogen oxides (NO) x NO (NOx) mainly originates from industrial production and is considered a major air pollutant. x NO is a toxic and harmful gas that, under certain conditions, can combine with hydrocarbons to produce pollutants such as photochemical smog. It can also irritate the eyes, cause acid rain that damages plants, reduce atmospheric visibility, and react with ozone in the air to create ozone layer depletion, thus worsening the environment upon which humans depend for survival. Reducing NO x Emissions, reducing NO in the ambient atmosphere x Concentration has become an important target for environmental pollution control in my country.

[0003] Selective catalytic reduction of NO x SCR (Self-Reducing Catalysis) technology refers to the process of removing NO by adding an additional reducing agent under the action of a catalyst. x The process of reducing NO to N2. CH4-SCR is a promising and effective method for removing NO. x The technology for removing NO from simulated flue gas using In / H-Beta has received close attention from scholars both domestically and internationally in recent years. Our research group previously conducted studies on removing NO from simulated flue gas using In / H-Beta. x While research has been conducted on In / H-Beta catalysts, their hydrothermal stability (water resistance) needs improvement, as the effects of high-temperature water vapor can lead to reduced or even lost catalyst activity. To address the issue of catalyst deactivation in the CH4-SCR reaction upon exposure to high-temperature water vapor, finding a zeolite support with good hydrothermal stability is an effective way to solve H2O poisoning. Summary of the Invention

[0004] To address the above technical problems, this invention discloses an SSZ-39 zeolite supported catalyst, its preparation method, and its application. The obtained catalyst exhibits better denitrification activity for CH4-SCR and good resistance to H2O and SO2.

[0005] The technical solution adopted by this invention is as follows:

[0006] A method for preparing an SSZ-39 zeolite supported catalyst includes the following steps:

[0007] Step S1: Disperse SSZ-39 zeolite in water, add an etchant to obtain a mixture, wherein the etchant is oxalic acid or citric acid, and the concentration of the etchant is 0.1–2.0 mol / L; react the mixture at a temperature of 70–85℃ for 2–10 h.

[0008] Step S2, after the reaction, filter, wash, dry the filter cake, grind and then calcine, the calcination temperature is 480-550℃, the calcination time is more than 2h, to obtain H-SSZ-39;

[0009] Step S3, In(NO3)3·xH2O is dissolved in water, H-SSZ-39 zeolite obtained in step S2 is added, and stirring is carried out at 80-90℃ for more than 6h, and then centrifugation, washing and drying are carried out, and then calcination is carried out, the calcination temperature is 480-550℃, the calcination time is at least 2h, to obtain In / H-SSZ-39 catalyst.

[0010] By adopting the technical scheme, after etching treatment by the etchant, the denitration activity of the In-loaded SSZ-39 zeolite catalyst is obviously improved.

[0011] As a further improvement of the application, in step S2, the calcination time is 3h or more.

[0012] As a further improvement of the application, in step S3, In(NO3)3·xH2O is dissolved in water, H-SSZ-39 zeolite obtained in step S2 is added, and stirring is carried out at 85℃ for 8h.

[0013] As a further improvement of the application, in step S3, the calcination time is 3h or more.

[0014] As a further improvement of the application, the preparation method of the SSZ-39 zeolite loaded catalyst further comprises: in step S3, in addition to adding H-SSZ-39 zeolite obtained in step S2, a metal oxide is also added, and the metal oxide is Co3O4, NiO or CeO2.

[0015] By adopting the technical scheme, In / H-SSZ-39 is combined with the metal oxide Co3O4, NiO or CeO2, which further improves the denitration activity of the catalyst and improves the stability of the catalyst under the condition of containing H2O and SO2.

[0016] As a further improvement of the application, the mass ratio of the metal oxide to H-SSZ-39 zeolite is 1:20-50.

[0017] As a further improvement of the application, the metal oxide is Co3O4. By adopting the technical scheme, the catalyst has better catalytic activity.

[0018] As a further improvement of the application, the mass ratio of the metal oxide to H-SSZ-39 zeolite is 1:30-50.

[0019] As a further improvement of the present application, the concentration of the etchant in the mixture of step S1 is 0.5-1.0 mol / L.

[0020] As a further improvement of the present application, the solid-liquid ratio of the zeolite to the aqueous etchant solution is 1g:15-30mL. Further, the solid-liquid ratio of the zeolite to the aqueous etchant solution is 1g:20mL.

[0021] As a further improvement of the present application, the etchant is OA. With this technical solution, the obtained catalyst has better catalytic activity.

[0022] As a further improvement of the present application, in step S1, the mixture is reacted at a temperature of 75-80℃.

[0023] As a further improvement of the present application, in steps S2 and S3, the heating rate of calcination is 3-6℃ / min.

[0024] The present application also discloses a SSZ-39 zeolite supported catalyst prepared by the preparation method of the SSZ-39 zeolite supported catalyst according to any one of the above.

[0025] The present application also discloses the application of the SSZ-39 zeolite supported catalyst according to the above, which is used for CH4-SCR denitration reaction. Further, it is used for CH4-SCR denitration under SO2 and H2O containing conditions.

[0026] As a further improvement of the present application, the conditions of the CH4-SCR denitration reaction are: CH4 concentration 400-600ppm, CH4 concentration to NO concentration ratio 1.5-2.0, O2 concentration 5-10vol%, SO2 concentration 0-50ppm, H2O concentration 5-10vol%, space velocity 11800-23600h -1 .

[0027] As a further improvement of the present application, the conditions of the SO2 and H2O containing denitration environment are: NO concentration 400ppm, CH4 concentration 600ppm, O2 concentration 10vol%, SO2 concentration 50ppm, H2O concentration 5vol%, space velocity 11800h -1 .

[0028] Compared with the prior art, the present application has the following beneficial effects:

[0029] The technical solution of the present application adopts the acid-etched H-SSZ-39, and the obtained modified In / H-SSZ-39 zeolite catalyst has better denitration activity for CH4-SCR. The In / H-SSZ-39(OA) catalyst modified by using oxalic acid etching has better denitration activity for NOx The conversion rate is as high as 62.6%, which is increased by 47.6% compared with the unmodified sample. Further, the catalyst In-Co3O4 / H-SSZ-39(OA) obtained by modification by Co3O4 has a NO x The conversion rate is as high as 83.1%, which is increased by 33% compared with the unmodified sample, and has good stability. After acid etching and modification by metal oxides, the catalyst has certain mesopores, the medium-strong acid acidity and the redox property are enhanced, the proportion of surface adsorbed oxygen is increased, and more stable N x O y The species are further reacted. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the CH4-SCR denitration activity comparison result of the CH4-SCR denitration activity of the catalysts modified by different etchants in the embodiment of the application, wherein (a) is the NO x conversion rate, (b) is the CH4conversion rate, and (c) is the CH4selectivity.

[0031] Figure 2 is the CH4-SCR denitration activity comparison result of the CH4-SCR denitration activity of the catalysts modified by different etchants in the embodiment of the application, wherein (a) is the NO x conversion rate, (b) is the CH4conversion rate, and (c) is the CH4selectivity.

[0032] Figure 3 is the CH4-SCR denitration activity comparison result of the CH4-SCR denitration activity of the catalysts modified by different etchants in the embodiment of the application, wherein (a) is the NO x conversion rate, (b) is the CH4conversion rate, and (c) is the CH4selectivity.

[0033] Figure 4 is the CH4-SCR denitration activity comparison result of the CH4-SCR denitration activity of the catalysts modified by different etchants in the embodiment of the application, wherein (a) is the NO x conversion rate, (b) is the CH4conversion rate, and (c) is the CH4selectivity.

[0034] Figure 5 is the CH4-SCR denitration activity comparison result of the CH4-SCR denitration activity of the catalysts modified by different etchants in the embodiment of the application, wherein (a) is the NO x conversion rate, (b) is the CH4conversion rate, and (c) is the CH4selectivity.

[0035] Figure 6 is the CH4-SCR denitration activity comparison result of the CH4-SCR denitration activity of the catalysts modified by different etchants in the embodiment of the application, wherein (a) is the NO xConversion, (b) is CH4conversion, (c) is CH4selectivity.

[0036] Figure 7 is the CH4-SCR catalytic activity comparison results of the modified catalyst of embodiment 8 of the present application under different water content, wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0037] Figure 8 is the In-MO modified by different metal oxides of the embodiment of the present application x / H-SSZ-39 catalyst CH4-SCR denitration activity results, wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0038] Figure 9 is the influence results of the modification amount of Co3O4 of embodiment 11 of the present application on the denitration performance of In-Co3O4 / H-SSZ-39(OA), wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0039] Figure 10 is the influence results of the O2concentration of embodiment 12 of the present application on the denitration performance of In-Co3O4 / H-SSZ-39(OA), wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0040] Figure 11 is the influence results of CH4 / NO of embodiment 13 of the present application on the denitration performance of In-Co3O4 / H-SSZ-39(OA), wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0041] Figure 12 is the influence results of space velocity of embodiment 14 of the present application on the denitration performance of In-Co3O4 / H-SSZ-39(OA), wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0042] Figure 13 is the influence results of water vapor concentration of embodiment 15 of the present application on the denitration performance of In-Co3O4 / H-SSZ-39(OA), wherein (a) is NO x Conversion, (b) is CH4conversion, (c) is CH4selectivity.

[0043] Figure 14 Figure 19 is the SO2 concentration effect on the In-Co3O4 / H-SSZ-39(OA) de-NOx performance of the present application embodiment 16, wherein (a) is NO conversion, (b) is CH4 conversion, and (c) is CH4 selectivity. x Figure 19 is the SO2 concentration effect on the In-Co3O4 / H-SSZ-39(OA) de-NOx performance of the present application embodiment 16, wherein (a) is NO conversion, (b) is CH4 conversion, and (c) is CH4 selectivity.

[0044] Figure 15 Figure 20 is the H2O and SO2 resistance cycling test results of the In-Co3O4 / H-SSZ-39(OA) of the present application embodiment 17.

[0045] Figure 16 Figure 21 is the H2O and SO2 resistance stability test results of the In-Co3O4 / H-SSZ-39(OA) of the present application embodiment 18. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present application are further described in detail below.

[0047] Embodiment 1

[0048] A preparation method of an SSZ-39 zeolite supported catalyst, comprising the following steps:

[0049] Step S1, 1 g of commercial H-SSZ-39 zeolite is ultrasonically dispersed in 20 mL of ultrapure water, and an etching agent oxalic acid (OA) with a concentration of 0.1 mol / L (i.e. 0.1 M) is added thereto, and the reaction temperature is selected as 80℃, and the reaction time is selected from short to long as 4-10 h.

[0050] Step S2, after the etching is completed, suction filtration is performed, and the filter cake is washed with ultrapure water for multiple times until the pH is neutral (to wash away non-framework aluminum and residual etching agent). The filter cake is taken out and placed in an oven with an oven temperature setting value of 80℃ and dried for more than 12 h. After drying, the etching modified zeolite is ground and placed in a muffle furnace, gradually increased from room temperature to 500℃ at a rate of 5℃ / min, and calcined for 3 h, to obtain the H-SSZ-39(OA) zeolite.

[0051] Step S3, the active metal In is introduced into the zeolite by ion exchange method, and the specific steps are as follows: first, In(NO3)3·xH2O and ultrapure water to a concentration of 0.066 M. 1 g of H-SSZ-39(OA) zeolite was ultrasonically dispersed in 33.33 mL of In(NO3)3 aqueous solution is stirred at 85℃ for 8 h. After ion exchange, the In exchanged sample is collected by high speed centrifugation, dried at 80℃ overnight, and then placed in a muffle furnace, gradually increased from room temperature to 500℃ at a rate of 5℃ / min, and calcined for 3 h, to obtain the In / H-SSZ-39(OA) catalyst.

[0052] By using this technical scheme, after etching treatment by the etching agent, the de-NOx activity of the In supported catalyst of the SSZ-39 zeolite is obviously improved.

[0053] Example 2

[0054] On the basis of Example 1, the difference of this example is that the etchant is citric acid (CA), and the others are the same as Example 1.

[0055] Comparative Example 1

[0056] On the basis of Example 1, the difference of this comparative example is that the etchant is EDTA, and the others are the same as Example 1.

[0057] Comparative Example 2

[0058] This comparative example is a blank sample, that is, on the basis of Example 1, the difference of this comparative example is that it is not etched.

[0059] The In / H-SSZ-39 catalysts obtained in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 were subjected to denitration experiments under SO2-free and H2O-free conditions. The experimental conditions were [NO] = 400 ppm, [CH4] = 600 ppm, [O2] = 10 vol%, and space velocity 23600 h-1. -1 The results are shown in Figure 1 It can be seen that the denitration efficiency of the In / H-SSZ-39 catalyst without etching modification does not reach 15% in CH4-SCR. As shown in Figure 1 (a), the denitration performance of the In / H-SSZ-39 zeolite catalysts modified by different kinds of etchants is obviously improved. Among them, the NO removal effect of the catalyst modified by OA is the best, which can reach ~ 40% of NO conversion at 550°C; the denitration activity of the catalyst modified by CA is slightly worse than that of OA, which has ~ 35% of NO conversion at 550°C; the activity of the catalyst modified by EDTA is the worst, which only has ~ 30% of NO conversion at the same temperature. x x x x The results are shown in

[0060] As shown in Figure 1 (b), the CH4 conversion rates of the In / H-SSZ-39 catalysts modified by OA, CA and EDTA and without etching modification have consistent overall trends and good coincidence. At 650°C, the CH4 conversion rates of the In / H-SSZ-39 catalysts modified by the three kinds of etchants from large to small are OA, CA and EDTA in turn. As can be seen from Figure 1 (c), at 500°C, the CH4 selectivity of the catalyst without etching modification is the lowest, which is 32%; and the CH4 selectivity of the catalysts modified by etchants is improved, among which the CH4 selectivity of the catalysts modified by OA and CA is obviously improved.​​​

[0061] Example 3

[0062] On the basis of Example 1, the difference of this example is that the concentration of etchant OA is 0.5M, 1.0M, 1.5M, 2.0M, etching time is 4h, etching temperature is 80℃, solid-liquid ratio of zeolite and etchant aqueous solution is 1g:20mL, and the reaction gas conditions of denitration experiment are unchanged.

[0063] Example 4

[0064] On the basis of Example 2, the difference of this example is that the concentration of etchant CA is 0.5M, 1.0M, 1.5M, 2.0M, etching time is 4h, etching temperature is 80℃, solid-liquid ratio of zeolite and etchant aqueous solution is 1g:20mL, and the reaction gas conditions of denitration experiment are unchanged.

[0065] The performance of the catalysts obtained in Example 3 and Example 4 is shown in Figure 2 Figure 2 (a) It can be seen that the In / H-SSZ-39 catalyst modified by 1.0M OA etching has the best activity in CH4-SCR, and can reach ~60% NO x conversion rate at 550℃; when the concentration is 0.5M, the denitration activity of the modified catalyst decreases slightly (about 50%), which may be due to the too low concentration of OA, and the effect of the zeolite is not significant; when the concentration of OA is increased to 1.5M or 2.0M, it can be seen that the activity of In / H-SSZ-39 catalyst further decreases, and its denitration activity decreases to below 50%.

[0066] Figure 2 (b) is the CH4conversion rate curve of In / H-SSZ-39 modified by different concentrations of OA in CH4-SCR reaction. The overall trend of CH4conversion rate under four concentrations is consistent, and CH4conversion rate increases with increasing temperature. Since the catalyst modified by 1.0M OA etching has the best denitration effect, its CH4conversion rate is higher than that of the catalysts modified by other concentrations at the same temperature, and CH4conversion rate reaches more than 80% at 650℃. The CH4conversion rate of the catalysts modified by other concentrations is slightly lower than that of 1.0M, but also increases with increasing activity. Figure 2 (c) is the CH4selectivity column chart of the catalysts modified by different concentrations of OA. The CH4selectivity of the four concentrations decreases with increasing temperature, and the overall trend is consistent. The CH4selectivity of In / H-SSZ-39 catalyst modified by 1.0M OA is the highest at 500℃, which is 48%. The CH4selectivity of In / H-SSZ-39 catalysts modified by 0.5M, 1.5M, 2.0M OA is slightly lower than that of 1.0M at 500℃, but all close to 45%.​

[0067] Furthermore, to compare the CH4-SCR catalytic activity under optimal etching conditions using OA and CA, activity tests were conducted on In / H-SSZ-39 etched with different CA concentrations (0.5M, 1.0M, 1.5M, 2.0M), while keeping other etching conditions constant. The test results are as follows: Figure 3 As shown.

[0068] Figure 3 (a) The denitrification activities of In / H-SSZ-39 catalysts modified with CA at concentrations of 0.5M, 1.0M, 1.5M, and 2.0M in CH4-SCR were compared. The 1.0M CA-modified catalyst showed the best denitrification effect, achieving 55% activity at 550℃. However, this was less than the 60% activity of the OA-modified In / H-SSZ-39 catalyst at the same concentration. Therefore, the OA-modified In / H-SSZ-39 catalyst exhibited better denitrification performance than the CA-modified catalyst. When the CA concentration was reduced to 0.5M, the NO... x The conversion rate decreased slightly to 50%, which was due to the reduction in etchant concentration. When the CA concentration was increased to 1.5M and 2.0M, a significant decrease in denitrification activity was observed compared to the 1.0M CA-etched modification. This is related to the decrease in NO content of the In / H-SSZ-39 catalyst after etching with different CA concentrations. x The conversion rate showed a consistent trend, which may be due to the amorphization of zeolite caused by excessively high etchant concentration, resulting in a smaller specific surface area and lower activity of the active species InO. + This is due to a decrease in load.

[0069] Figure 3 (b) shows the CH4 conversion curves of the catalysts after etching and modification with different concentrations of CA. It can be seen that the CH4 conversion trend of the catalysts after etching with several concentrations of CA is consistent with the CH4 conversion of the catalysts after etching and modification with OA. At the reaction temperature of 650℃, its CH4 conversion can reach 80%, which is about 5% lower than that of OA. At the same time, comparing the CH4 conversion of the catalysts after etching and modification with different concentrations of CA, it is found that its CH4 conversion is slightly lower than that of the catalysts after etching and modification with OA. Figure 3 (c) shows the CH4 selectivity curves of the catalysts after etching and modification with different concentrations of CA. At 500℃, the CH4 selectivity of the catalyst after etching and modification with 1.0 M CA did not reach 45%, while the CH4 conversion rate of the catalyst after etching and modification with 1.0 M OA at 500℃ could reach over 45%. Furthermore, at the same temperature and concentration, the CH4 selectivity of the catalyst after etching and modification with OA was consistently higher than that of the catalyst after etching and modification with CA. Therefore, in summary, by comparing the NO content of the catalysts... xThe conversion rate, CH4conversion rate, CH4selectivity results show that the de-NOx activity of the catalyst modified by OA etching is better than that of the catalyst modified by CA etching.

[0070] Example 5

[0071] On the basis of Example 1, the etchant OA was used, the concentration of the etchant OA was 1M, the solid-liquid ratio was 1g:20mL, the etching reaction temperature was 80°C, and the etching time was changed, and the etching modification time was 2h, 4h, 6h, 8h and 10h; the de-NOx reaction conditions of the obtained catalyst were as follows: [NO] = 400ppm, [CH4] = 600ppm, [O2] = 10vol%, and the others were the same as in Example 1.

[0072] The de-NOx activity of the In / H-SSZ-39 catalysts with etching modification times of 2h, 4h, 6h, 8h and 10h was as shown in Figure 4

[0073] Figure 4 (a) is the NO conversion rate curve of the In / H-SSZ-39 catalysts modified by different OA etching times, and it can be found that when the etching time is 4h, the catalyst has a NO conversion rate of 60.8% at 550°C, while when the etching time is 2h, 6h, 8h or 10h, the de-NOx activity is all decreased to below 50%, and according to the literature report, this may be due to the decrease of the pore volume of the zeolite caused by the change of the etching time. x x

[0074] Figure 4 (b) is the CH4conversion rate curve of the In / H-SSZ-39 catalysts modified by different OA etching times, and the CH4conversion rate curves of the catalysts modified by the etching times are almost consistent, and the CH4conversion rate increases with the increase of the temperature, among which the CH4conversion rate of the In / H-SSZ-39 catalyst modified by etching for 4h is the highest and can reach 90% at 650°C, while the CH4conversion rates of the catalysts modified by etching for 2h, 6h, 8h and 10h are all about 80%. Figure 4 (c) is the CH4selectivity column chart of the catalysts modified by different OA etching times, and when the etching time is 4h, the CH4selectivity of the catalyst can reach 45% at 500°C; when the etching time is 2h and 6h, the CH4selectivity of the catalyst is slightly lower, about 40%; and when the etching time is increased to 8h and 10h, the CH4selectivity of the catalyst is decreased to 35% and 30%.

[0075] By comparing the NO conversion rate, CH4conversion rate and CH4selectivity of the catalysts modified by different OA etching times, it can be found that the de-NOx effect is the best and the CH4selectivity is the highest after etching modification for 4h. x ​​​​

[0076] Example 6

[0077] On the basis of Example 1, in this embodiment, first, an aqueous indium nitrate solution with a concentration of 0.066 M was prepared using In(NO3)3xH2O and ultrapure water, and 1 g of H-SSZ-39(OA) zeolite was ultrasonically dispersed into 33.33 mL of the aqueous In(NO3)3 solution; the etchant concentration was 1 M, the etching temperature was changed, and OA etching modification was performed at 70°C, 75°C, 80°C, and 85°C, respectively, and CH4-SCR activity tests were performed, with the other conditions being the same as in Example 1. The NO x conversion, CH4conversion, and CH4selectivity are shown in Figure 5

[0078] Figure 5 (a) is the NO conversion curve of the In / H-SSZ-39 catalyst after OA etching modification at different etching temperatures. It can be found that the NO conversion of the catalyst after etching modification at different temperatures is consistent in overall trend, and the NO conversion of the catalyst after etching modification at 80°C is as high as 60.8% at 550°C, and the deNOx activity of the catalyst after etching modification at other temperatures decreases slightly, and the deNOx activity of the catalyst decreases to below 60%. x x x

[0079] Figure 5 (b) is the CH4conversion curve of the catalyst after etching modification at different temperatures. It can be found from the figure that the CH4conversion of the catalyst after etching modification at 80°C is as high as 92%, and the CH4conversion of the catalyst after etching modification at 70°C, 75°C, and 85°C is lower than 90%. Figure 5 (c) is the CH4selectivity curve of the catalyst. It can be found that the CH4selectivity of the catalyst after etching modification at 80°C is as high as 50%, the CH4selectivity of the catalyst after etching modification at 70°C and 75°C is about 45%, and the CH4selectivity of the catalyst after etching modification at 85°C decreases to below 40%.

[0080] Example 7

[0081] On the basis of Example 1, in this embodiment, the solid-liquid ratio of the etching process was changed, and OA etching modification was performed under the conditions of a solid-liquid ratio of 1 g: 15 mL, 1 g: 20 mL, 1 g: 25 mL, and 1 g: 30 mL, respectively, and the deNOx activity test results of the modified catalyst are shown in Figure 6

[0082] Figure 6 (a) is the NO conversion curve of the In / H-SSZ-39 catalyst after etching modification at different etching temperatures. It can be found that the NO conversion of the catalyst after etching modification at different temperatures is consistent in overall trend, and the NO conversion of the catalyst after etching modification at 80°C is as high as 60.8% at 550°C, and the deNOx activity of the catalyst after etching modification at other temperatures decreases slightly, and the deNOx activity of the catalyst decreases to below 60%. x ​​​​​The conversion rate curve of CH4-SCR of the In / H-SSZ-39 catalyst modified by etching under different solid-liquid ratios shows that the CH4conversion rate curves of the In / H-SSZ-39 catalysts modified by etching under different solid-liquid ratios are almost coincident, and the CH4conversion rate increases with the increase of temperature, indicating that the change of the solid-liquid ratio has little effect on the CH4conversion rate of the catalyst. The CH4conversion rate of the catalyst can reach 90% at 650°C. x The conversion rates are 59.1% and 59.3%, respectively.

[0083] Figure 6 (b) The CH4conversion rate curve of the In / H-SSZ-39 catalyst modified by etching under different solid-liquid ratios shows that the CH4conversion rate curves of the In / H-SSZ-39 catalysts modified by etching under different solid-liquid ratios are almost coincident, and the CH4conversion rate increases with the increase of temperature, indicating that the change of the solid-liquid ratio has little effect on the CH4conversion rate of the catalyst. The CH4conversion rate of the catalyst can reach 90% at 650°C.

[0084] Figure 6 (c) The CH4selectivity curve of the catalyst modified by etching under different solid-liquid ratios shows that when the solid-liquid ratio is 1g:25mL and 1g:30mL, the CH4selectivity is 44.3% and 43.6%, respectively, and when the solid-liquid ratio is 1g:15mL and 1g:30mL, the CH4selectivity is high. In summary, the test results of the CH4-SCR of the catalysts modified by etching under different solid-liquid ratios show that the solid-liquid ratio has little effect on the denitration effect of the catalyst, and the solid-liquid ratio of 1g:25mL is the best.

[0085] Example 8

[0086] The application of an SSZ-39 zeolite supported catalyst for SO2 and H2O resistant denitration in CH4-SCR. In this example, the catalyst of Example 1 was used. Then, CH4-SCR activity tests were carried out under the conditions of water vapor concentrations of 2.5vol%, 5vol%, 7.5vol%, and 10vol%, respectively, and compared with the CH4-SCR activity of the In / H-SSZ-39 catalyst without etching under the condition of 2.5vol% H2O, and the test results are shown in Figure 7

[0087] Figure 7 (a) The NO x conversion rate curve of the In / H-SSZ-39 catalyst modified by etching under the optimized OA etching modification conditions shows that compared with the water-free condition, the denitration activity of the catalyst decreases with the increase of the water vapor concentration. When the reaction gas contains 2.5vol% H2O, the NO x conversion rate of the catalyst is 57.7%. When the water vapor content in the mixed gas is increased to 5.0vol%, 7.5vol%, and 10vol%, respectively, the NO x ​The conversion rates were 51.3%, 45.7%, and 42.2%, respectively, which was better than the denitration activity of Beta zeolite under the same water vapor concentration, indicating that the In / H-SSZ-39 zeolite catalyst had certain H2O resistance compared to other types of zeolite catalysts, but still needed to be further enhanced; and the In / H-SSZ-39 catalyst without OA etching modification had a NO x The conversion rate was only 10% at most. It was also found that when the reaction gas contained water vapor, the activity temperature window of the catalyst became narrow, and the optimal activity temperature moved from 550 DEG C to 600 DEG C.

[0088] Figure 7 (b) is the CH4conversion rate curve of the In / H-SSZ-39 catalyst when different concentrations of water vapor are introduced into the reaction gas. It can be found that when no H2O is added to the reaction gas, the CH4conversion rate of the catalyst in different temperature ranges is higher than that under the condition of containing water vapor; at the same time, with the continuous increase of the water vapor concentration in the reaction gas, the CH4conversion rate of the catalyst gradually decreases. Figure 7 (c) is the CH4selectivity curve of the catalyst under the activity test of the catalyst under the condition of containing water. When no H2O is added to the reaction gas, the CH4selectivity of the catalyst at 500 DEG C is 46%; when the mixed gas contains 2.5vol% H2O, the CH4selectivity is slightly lower than that under the dry condition, which is 44%; with the gradual increase of the water vapor concentration in the reaction gas, the CH4selectivity of the catalyst gradually decreases, especially when it is increased to 7.5vol% H2O and 10vol% H2O, the CH4selectivity is reduced to below 30%, which indicates that water vapor has a significant inhibitory effect on the CH4selectivity of the catalyst.

[0089] Example 9

[0090] On the basis of Example 1, in step S3 of the preparation method of the SSZ-39 zeolite supported catalyst, in addition to the H-SSZ-39(OA) zeolite obtained in step S2, a metal oxide is also added, and the metal oxide is Co3O4. The mass ratio of the metal oxide to H-SSZ-39(OA) is 1:20.

[0091] Example 10

[0092] On the basis of Example 9, the difference between this embodiment and Example 9 is that the metal oxide is NiO, and the others are the same as Example 9.

[0093] Example 11

[0094] On the basis of Example 9, the difference between this embodiment and Example 9 is that the metal oxide is CeO2, and the others are the same as Example 9.

[0095] Comparative Example 3

[0096] On the basis of Example 9, the difference of the present comparative example is that the metal oxide is Fe2O3, and others are the same as Example 9.

[0097] Comparative Example 4

[0098] On the basis of Example 9, the difference of the present comparative example is that the metal oxide is MnO2, and others are the same as Example 9.

[0099] Comparative Example 5

[0100] On the basis of Example 9, the difference of the present comparative example is that the metal oxide is Cr2O3, and others are the same as Example 9.

[0101] The catalysts prepared in Examples 9-11 and Comparative Examples 3-5 were subjected to denitration experiments, and the reaction conditions were: [NO] = 400 ppm, [CH4] = 600 ppm, [O2] = 10 vol%, and space velocity 23600 h-1. -1 The In-MO x / H-SSZ-39(OA) catalysts prepared in different metal oxides were subjected to CH4-SCR denitration activity as shown in Figure 8 .

[0102] Figure 8 (a) is the NO x conversion rate curve of the In-MO x / H-SSZ-39(OA) catalyst in the CH4-SCR reaction, it can be found that after modification of Co3O4, the catalyst can achieve 91.4% of NO x conversion rate under the condition of no H2O and no SO2; at the same time, the modification of CeO2 and NiO also improves the denitration activity of the catalyst, and the NO x conversion rate can reach about 72% at 550°C, while the modification of Cr2O3, MnO2 and Fe2O3 does not significantly improve the activity of the catalyst, and the NO x conversion rate is the highest at 550°C, which is 50.6%, 30.4% and 22.5%, respectively.

[0103] Figure 8 (b) is the CH4 conversion rate curve of the In-MO x / H-SSZ-39(OA) catalyst in the CH4-SCR reaction, it can be seen that the CH4 conversion rate of the catalyst after adding metal oxides is significantly improved compared with the In / H-SSZ-39(OA) catalyst, and the CH4 conversion rate of the six metal oxides modified catalysts is more than 97% at 650°C. Figure 8 (c) is the CH4 conversion rate curve of the In-MO xThe CH4 selectivity of the / H-SSZ-39(OA) catalyst in the CH4-SCR reaction is the best due to the optimal catalytic activity of Co3O4 modification. Therefore, its CH4 selectivity is also the best compared to other metal oxide modifications, reaching 52% at 500℃, while the CH4 selectivity of other oxide modifications is all below 40%.

[0104] Example 12

[0105] Based on Example 9, the difference in this example lies in the amount of metal oxide modification. In step S3, In-Co3O4 / H-SSZ-39(OA) catalysts were prepared according to the following mass ratios of H-SSZ-39(OA) zeolite to Co3O4: 5g:1g, 10g:1g, 20g:1g, 30g:1g, 40g:1g, and 50g:1g, with other conditions the same as in Example 9.

[0106] The obtained catalyst was subjected to denitration experiments under the following reaction conditions: [NO] = 400 ppm, [CH4] = 600 ppm, [O2] = 10 vol%. The space velocity was 23600 h⁻¹. -1 With a water vapor concentration of 5 vol%, the catalyst was tested in CH4-SCR as follows: Figure 9 As shown.

[0107] from Figure 9 As shown in (a), the In-Co3O4 / H-SSZ-39 catalysts prepared under different Co3O4 modification conditions exhibit different denitrification activities in CH4-SCR. The NO content of the In-Co3O4 / H-SSZ-39(OA) catalysts prepared with Co3O4 modification to zeolite mass ratios of 1g:5g, 1g:10g, 1g:20g, 1g:30g, 1g:40g, and 1g:50g is significantly higher. x The highest conversion rates were 49.4%, 49.0%, 58.3%, 80.2%, 73.4%, and 70.9%, respectively. The denitrification activity of the catalyst decreased with increasing Co3O4 modification, likely because increased Co3O4 promoted the non-selective oxidation of CH4, leading to reduced activity. Furthermore, a Co3O4 modification ratio below 1g:30g also reduced the catalyst's denitrification activity. This is because less Co3O4 reduces the participation of activated CH4 products in the NO reduction to N2 process, thus decreasing activity.

[0108] from Figure 9(b) can be seen that the catalyst from 400 ℃ CH4 conversion began, CH4 conversion at 500 ℃ and higher temperature is more obvious, to 650 ℃ has been completely converted, six Co3O4 modification ratio at 650 ℃ CH4 conversion rate of 99%, indicating that CH4 has been completely converted, compared with In / H-SSZ-39(OA) catalyst at the same temperature CH4 conversion rate, indicating that Co3O4 added indeed facilitate CH4 conversion. From Figure 9 (c) can be seen that with the increase of temperature CH4 selectivity decreases, Co3O4 modification amount is 1g:30g, the catalyst at 500 ℃ CH4 selectivity is the highest of 54.2%, under other modification amount, CH4 selectivity slightly reduced, which is consistent with the change of catalyst activity in the reaction.

[0109] Example 13

[0110] In the process of CH4-SCR reaction, O2 concentration will affect CH4 conversion and then affect the denitration activity of the catalyst. In this embodiment, the effect of O2 concentration on the denitration performance of In-Co3O4 / H-SSZ-39(OA) catalyst is explored. Specifically: change the oxygen concentration in the reaction gas (3vol%, 5vol%, 8vol%, 10vol%, 15vol%, 20vol%), and evaluate the activity of the catalyst of Example 9. Other gas parameters are: [NO]=400ppm, [CH4]=600ppm, space velocity is 23600h -1 , [H2O]=5vol%, the NO x conversion rate, CH4 conversion rate and CH4 selectivity of In-Co3O4 / H-SSZ-39(OA) catalyst are tested. Figure 10

[0111] Figure 10 (a) is the NO x conversion curve of In-Co3O4 / H-SSZ-39(OA) catalyst under different O2 concentrations. It can be seen that with the increase of O2 concentration, the NO x conversion rate increases, which is due to the increase of O2 concentration promotes CH4 activation, when O2 concentration increases to 10vol%, at this time the catalyst can reach 80.3% of NO x conversion rate at 600 ℃. With the further increase of O2 concentration, the denitration activity of the catalyst begins to decline, when the O2 concentration in the reaction gas is 15% and 20%, the NO x removal rate of In-Co3O4 / H-SSZ-39(OA) catalyst at 600 ℃ is only 59.8% and 58.7% respectively.

[0112] Figure 10 ​(b) is the CH4conversion rate curve of the In-Co3O4 / H-SSZ-39(OA) catalyst under different O2concentrations. It can be found that the CH4conversion rate trends of the catalyst under several O2concentrations are basically consistent, and the CH4conversion rate is the highest at 90.1% when the O2content in the reaction gas is 10 vol% at 600°C; when the O2concentration is increased to 15 vol% and 20 vol%, the CH4conversion rate of the catalyst decreases to 87.8% and 82.8%, respectively.

[0113] Figure 10 (c) is the CH4selectivity column chart of the catalyst In-Co3O4 / H-SSZ-39(OA). It can be found that the CH4selectivity of the catalyst increases with the increase of O2concentration, and the CH4selectivity is the highest at 54.2% when the O2concentration is 10 vol%, and the CH4selectivity of the catalyst decreases when the O2concentration is further increased.

[0114] Example 14

[0115] In the CH4-SCR reaction, CH4 / NO can affect the catalyst deNOx activity, and in this embodiment, the CH4 / NO ratio is tested. Specifically, on the basis of Example 13, the catalyst of Example 9 is used to explore the effect of different CH4 / NO on the deNOx performance of the In-Co3O4 / H-SSZ-39(OA) catalyst, and the deNOx activity test is carried out under three reaction conditions of CH4 / NO being 1:1, 1.5:1 and 2:1, respectively. The CH4-SCR test results of the In-Co3O4 / H-SSZ-39(OA) catalyst under 5 vol% H2O are shown in Figure 11

[0116] Figure 11 (a) It can be found that the NO x conversion rate curves of the three ratios are consistent as a whole, and the NO x conversion rates of the In-Co3O4 / H-SSZ-39(OA) catalyst are 65.0%, 80.3% and 71.5% respectively when CH4 / NO is 1.0, 1.5 and 2.0 at 600°C, so according to the NO x removal rate results, the optimal reaction condition of CH4 / NO is 1.5; it is also found that the deNOx activity of the catalyst begins to increase significantly at 500°C, which indicates that the catalyst exhibits extremely high catalytic performance in the temperature range of 500-600°C, which may be related to the selective catalytic reduction of CH4 in this temperature range.

[0117] Figure 11 ​(b) The CH4conversion rate curves of In-Co3O4 / H-SSZ-39(OA) catalysts at different CH4 / NO can be found that when the concentration of CH4in the reaction gas is 400 ppm and 600 ppm, there is a higher CH4conversion rate compared to the concentration of CH4of 800 ppm, which may be that low concentration of CH4can be completely utilized, and when the concentration of CH4increases to 800 ppm, it cannot be completely utilized, thus resulting in a slight decrease in CH4conversion rate.

[0118] Figure 11 (c) The CH4selectivity column chart of In-Co3O4 / H-SSZ-39 catalysts can be found that when the concentration of CH4is 400 ppm, 600 ppm and 800 ppm respectively, the CH4selectivity of In-Co3O4 / H-SSZ-39(OA) catalyst at 500°C is 56.4%, 54.2% and 42.9% respectively, and the selectivity decreases with the increase of CH4concentration, which is consistent with the CH4conversion rate of CH4at high concentration.

[0119] Example 15

[0120] In the CH4-SCR reaction, the space velocity will affect the deNOx activity of the catalyst. This embodiment explores the influence of different space velocities on the deNOx performance of In-Co3O4 / H-SSZ-39(OA) catalyst. Specifically, on the basis of Example 13, the catalyst of Example 9 was used, and CH4-SCR deNOx activity tests were carried out at space velocities of 11800 h-1, 23600 h-1, 35400 h-1and 47200 h-1respectively. -1 -1 -1 -1 The CH4-SCR test results of the catalyst In-Co3O4 / H-SSZ-39(OA) under 5vol% H2O test are shown in Figure 12 .

[0121] From Figure 12 (a), it can be found that as the space velocity decreases, the NO x conversion rate increases. When the space velocity is 11800 h -1 , the catalyst can achieve a NO x conversion rate of 86.7% at 600°C, and as the space velocity increases, the NO x conversion rate of the catalyst in CH4-SCR decreases. When the space velocities are 23600 h -1 , 35400 h -1 and 47200 h -1 , the NO x ​​​The conversion rates dropped to 80.3%, 60.4%, and 50.0%, respectively. Therefore, in order to ensure that the catalyst has a high deNOx efficiency in the reaction, it is crucial to select a suitable space velocity. In the subsequent cyclic test and stability test, the space velocity condition was selected as 11800 h -1 The CH4-SCR deNOx activity test was performed.

[0122] Figure 12 (b) is the CH4conversion rate curve of the In-Co3O4 / H-SSZ-39(OA) catalyst under different space velocity adaptive conditions. It can be seen that, under the space velocity condition of 11800 h -1 , the CH4conversion rate of the catalyst reached 98.6% at 600°C. When the space velocity was increased to 23600 h -1 , 35400 h -1 , and 47200 h -1 , the CH4conversion rates at 600°C were 90.1%, 76.1%, and 64.8%, respectively. Compared with the CH4conversion rate results under high space velocity, the CH4of the In-Co3O4 / H-SSZ-39(OA) catalyst was almost completely converted at 600°C when the space velocity was 11800 h -1 . When the space velocity was increased to 23600 h -1 , 35400 h -1 , and 47200 h -1 , the CH4conversion rate of the catalyst at 600°C did not reach more than 95%. Only when the reaction temperature was increased to 650°C, the CH4conversion rate of the In-Co3O4 / H-SSZ-39(OA) catalyst reached 99%, and most of the CH4was converted in the form of non-selective oxidation at high temperature.

[0123] Figure 12 (c) is the CH4selectivity column chart of the In-Co3O4 / H-SSZ-39(OA) catalyst. It can be found that the CH4selectivity of the catalyst can reach 58.8% when the space velocity is 11800 h -1 . When the space velocity was increased to 23600 h -1 , 35400 h -1 , and 47200 h -1 , the CH4selectivity of the In-Co3O4 / H-SSZ-39(OA) catalyst began to decrease, and the CH4selectivity at 500°C was the highest, respectively 54.2%, 50.6%, and 48.8%.

[0124] Example 16

[0125] In the actual flue gas in industry often contains a certain amount of water vapor, the influence of water vapor content on the catalyst denitration performance in the experimental test process is particularly important. This embodiment explores the influence of different water vapor contents in the reaction gas on the denitration performance of In-Co3O4 / H-SSZ-39(OA) catalyst. The catalyst of Example 9 is used to evaluate and test the CH4-SCR denitration of In-Co3O4 / H-SSZ-39(OA) catalyst under the conditions of water vapor concentration of 5vol%, 7.5vol%, 10vol%, and 15vol%, respectively. The experimental test results are shown in Figure 13

[0126] Figure 13 (a) It was found that the In-Co304 / H-SSZ-39(OA) catalyst showed an increase in the selectivity to propene with increasing water vapor concentration in the reaction gas The activity of the catalyst begins to decline, and the activity temperature window of the catalyst also narrows as the water content increases. When the water content in the reaction gas is 5vol%, the In-Co3O4 / H-SSZ-39(OA) catalyst can achieve 80% NO x conversion at 600℃; however, when the water vapor concentration in the reaction gas is increased to 7.5vol%, 10vol%, and 15vol%, respectively, the NO x conversion of the In-Co3O4 / H-SSZ-39(OA) catalyst is 70.1%, 67.5%, and 58.6%, respectively. It can be seen that the increase in water vapor concentration leads to an increase in catalyst activity inhibition.

[0127] Figure 13 (b) is the CH4 conversion curve of In-Co3O4 / H-SSZ-39(OA) catalyst under different water vapor concentrations. It can be found that the CH4 conversion trends are consistent under several water vapor concentrations. At 600℃, the water vapor content in the reaction gas is 5vol%, 7.5vol%, 10vol%, and 15vol%, respectively. At this time, the CH4 conversion rate of the catalyst is 90.1%, 85.4%, 87.8%, and 83.3%, respectively. It can be seen that the increase in water vapor content will inhibit the selective conversion of CH4 of In-Co3O4 / H-SSZ-39(OA) catalyst.

[0128] Figure 13 (c) is the CH4 selectivity column chart of In-Co3O4 / H-SSZ-39 catalyst under different water vapor concentrations. It can be seen that the catalyst can achieve 55% CH4 selectivity at 500℃. As the water vapor concentration in the reaction gas increases, the CH4 selectivity begins to decline. When the water vapor concentration increases to 7.5vol% and 10vol%, the CH4 selectivity decreases to about 45%. When the water vapor content is further increased to 15vol%, the CH4 selectivity of the catalyst decreases to 40%.

[0129] Example 17 ​

[0130] The present example investigates the effect of SO2 concentration on the deNOx performance of the In-Co3O4 / H-SSZ-39 catalyst in CH4-SCR. The catalyst of Example 9 was used to perform CH4-SCR deNOx activity tests at 0 ppm, 50 ppm, and 100 ppm SO2 concentrations. The test results are shown in Figure 14 x Figure 9, which are the NOx conversion curves of the catalyst at different SO2 concentrations. When the reaction gas only contains 5 vol% H2O, the catalyst has a maximum NOx conversion of 80% at 600°C. When 50 ppm SO2 is introduced into the reaction gas, the catalyst has the highest activity at 600°C, at which the NOx conversion is 60%. When the SO2 concentration in the reaction gas is increased to 100 ppm, it can be seen that the catalyst is severely poisoned by SO2, and the NOx conversion is only about 20% at 600°C. Actual industrial flue gas has a low SO2 concentration, so subsequent cyclic experiments and stability experiments will be tested at a SO2 concentration of 50 ppm. -1 .

[0131] Figure 14 (a) is the NOx conversion curve of the In-Co3O4 / H-SSZ-39 (OA) catalyst at different SO2 concentrations. When the reaction gas only contains 5 vol% H2O, the catalyst has a maximum NOx conversion of 80% at 600°C. When 50 ppm SO2 is introduced into the reaction gas, the catalyst has the highest activity at 600°C, at which the NOx conversion is 60%. When the SO2 concentration in the reaction gas is increased to 100 ppm, it can be seen that the catalyst is severely poisoned by SO2, and the NOx conversion is only about 20% at 600°C. Actual industrial flue gas has a low SO2 concentration, so subsequent cyclic experiments and stability experiments will be tested at a SO2 concentration of 50 ppm. x x x x

[0132] Figure 14 (b) is the CH4 conversion curve of the In-Co3O4 / H-SSZ-39 (OA) catalyst at different SO2 concentrations. It can be seen that when no SO2 is added to the reaction gas, the CH4 conversion of the catalyst is 90.1% at 600°C. When 50 ppm SO2 is introduced into the reaction gas, the CH4 conversion of the catalyst is 58.9% at 600°C. It can be seen that SO2 not only reduces the NOx conversion of the catalyst, but also inhibits the CH4 conversion. After addition of SO2 at 50 ppm and 100 ppm The CH4conversion of the catalyst dropped to 83.4% at 600 °C Figure 14 x

[0133] Figure 15 ​​​​​​​(c) is a bar chart of the CH4 selectivity of the In-Co3O4 / H-SSZ-39(OA) catalyst at different SO2 concentrations. It can be seen that without SO2 added to the reaction gas, the CH4 selectivity of the catalyst reaches 55% at 500℃. When 50 ppm and 100 ppm SO2 are added to the reaction gas, the CH4 selectivity of the catalyst decreases to 38.3% and 33.2% at the same temperature, respectively. Therefore, increasing the SO2 concentration in the reaction gas reduces the CH4 selectivity of the catalyst.

[0134] Example 17

[0135] This embodiment investigates the cycling performance of the In-Co3O4 / H-SSZ-39(OA) catalyst under operating conditions. The catalyst from Example 9 was used for the cycling test experiment under the following conditions: [NO] = 400 ppm, [CH4] = 600 ppm, [O2] = 10 vol%, [H2O] = 5 vol%, [SO2] = 50 ppm, and space velocity of 11800 h⁻¹. -1 Heating rate 10℃ / min, catalyst in CH4-SCR NO x The conversion rate over time curve is as follows: Figure 16 As shown. It can be seen that at an airspeed of 11800 h... -1 After undergoing a cycle test containing H2O and SO2, the catalyst showed NO at 600℃. x The highest conversion rate reached 57.1%, and the denitrification activity of the catalyst in other temperature ranges (500℃ and 650℃) was slightly lower than that in the first cycle. The results of the second cycle test show that the activity decreased across all temperature ranges compared to the first cycle test, with the best denitrification activity of 51.3% at 600℃. When the catalyst underwent the third cycle, NO... x The decrease in conversion rate was not as significant as in the first two cycles. This is because after the catalyst underwent the first two SO2 poisoning reactions, the subsequent cycle experiments were less affected by SO2 poisoning. Therefore, the catalyst exhibits better cycle performance under reaction conditions containing H2O and SO2.

[0136] Example 18

[0137] This embodiment investigates the denitrification stability of the In-Co3O4 / H-SSZ-39(OA) catalyst under operating conditions. The catalyst from Example 9 was used for stability testing, and the experimental conditions were: [NO] = 400 ppm, [CH4] = 600 ppm, [O2] = 10 vol%, [H2O] = 5 vol%, [SO2] = 50 ppm, and space velocity of 11800 h⁻¹. -1 Catalyst in CH 4 -SCR NO xThe conversion rate over time curve is as follows: ​ As shown. It can be seen that at an airspeed of 11800 h... -1 Under these conditions, the catalyst still contained 68.1% NO at the start of the reaction, even with 5 vol% H2O and 50 ppm SO2. x The conversion rate gradually decreased with increasing reaction time, and the catalyst's denitrification performance began to steadily decline. After a 7-hour stability test, the NO conversion rate... x The conversion rate gradually decreased from 68.1% to 55.3%, indicating that the catalyst has good stability.

[0138] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method of making an SSZ-39 zeolite supported catalyst, characterized by, Comprising the following steps: Step S1, ultrasonic dispersion of H-SSZ-39 zeolite in water, addition of etching agent to obtain a mixture, wherein the etching agent is oxalic acid or citric acid, the concentration of the etching agent is 0.1-2.0 mol / L; the mixture is reacted at a temperature of 75-80 ℃, and the reaction time is 2-10 h; in the mixture, the concentration of the etching agent is 0.5-1.0 mol / L; the solid-liquid ratio of the zeolite to the etching agent aqueous solution is 1 g:15-30 mL; Step S2, after the reaction is completed, filtration, washing, drying of the filter cake, grinding, and then calcination at a calcination temperature of 480-550 ℃ for more than 2 h to obtain the etched H-SSZ-39 zeolite; Step S3, In(NO3)3· x H2O is dissolved in water, and H-SSZ-39 zeolite obtained in step S2 is added. The mixture is stirred at a constant temperature of 80-90℃ for more than 6 hours. After centrifugation, washing, and drying, it is then calcined at a temperature of 480–550℃ for at least 2 hours to obtain the In / H-SSZ-39 catalyst.

2. The method of making a SSZ-39 zeolite supported catalyst of claim 1, wherein, Further comprising: in step S3, in addition to the H-SSZ-39 zeolite obtained in step S2, a metal oxide is also added, the metal oxide is Co3O4, NiO or CeO2; the mass ratio of the metal oxide to the H-SSZ-39 zeolite is 1:20-50.

3. The method of making a SSZ-39 zeolite supported catalyst of claim 2, wherein: The metal oxide is Co3O4, and the mass ratio of the metal oxide to the H-SSZ-39 zeolite is 1:30-50.

4. The method of making a SSZ-39 zeolite supported catalyst of claim 3, characterized by: The etching agent is oxalic acid.

5. The method of making a SSZ-39 zeolite supported catalyst according to claim 3, characterized by: In steps S2 and S3, the heating rate of calcination is 3-6 ℃ / min.

6. A SSZ-39 zeolite supported catalyst characterized by: Prepared by the preparation method of the SSZ-39 zeolite supported catalyst as claimed in any one of claims 1-5.

7. The use of a SSZ-39 zeolite supported catalyst according to claim 6, wherein: Used for CH4-SCR denitration reaction.

8. The use of a SSZ-39 zeolite supported catalyst according to claim 7, characterized by: The conditions for the CH4-SCR de-NOx reaction are: CH4concentration 400 - 600 ppm, CH4concentration to NO concentration ratio 1.5 - 2.0, O2concentration 5 - 10 vol%, SO2concentration 0 - 50 ppm, H2O concentration 5 - 10 vol%, space velocity 11800 - 23600 h -1 .

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