Extruded honeycomb simultaneous denitration and decarburization molecular sieve catalyst, its preparation method and application

Abstract

The application discloses an extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst and a preparation method thereof, and belongs to the field of gas purification. The molecular sieve catalyst takes a molecular sieve-based honeycomb ceramic as a substrate, and transition metal composite oxides are loaded on the substrate; transition metals in the transition metal composite oxides are selected from at least two of copper, cerium, manganese and iron. The catalyst can simultaneously catalyze an ammonia selective reduction of nitrogen oxide reaction and a carbon monoxide oxidation reaction, realizes simultaneous catalytic elimination of NO and CO on the same catalytic bed, and can restore the activity through a reduction regeneration method after the catalyst is poisoned by SO2; after regeneration, the removal efficiencies of NO and CO can both reach more than 90%.

Description

TECHNICAL FIELD

[0001] The present application relates to a catalyst for removing nitrogen oxides and carbon monoxide in exhaust gas and a preparation method thereof, and belongs to the field of gas purification. BACKGROUND

[0002] NOx and CO are two typical atmospheric pollutants in industrial fixed source flue gas. The massive emission of nitrogen oxides can cause photochemical smog, acid rain, ozone layer destruction and other environmental problems; carbon monoxide is a common toxic gas that can rapidly bind with human hemoglobin to cause respiratory disorders, and can also react with other atmospheric pollutants to further affect the atmospheric environment. With the widespread application of flue gas denitration facilities, the total amount of NOx in flue gas has been effectively controlled by using the selective catalytic reduction (SCR) method, but the emission of CO in industrial fixed source flue gas has not been effectively solved.

[0003] For the treatment of internal combustion engine exhaust gas, the three-way catalytic converter (TWC) for gasoline engine and the catalytic oxidation converter (DOC) for diesel engine using noble metal as active component can efficiently remove CO in the exhaust gas. However, for the treatment of fixed source flue gas, the flue gas volume is huge, and the use of noble metal catalysts is costly, which is difficult for general users to accept; the fixed source flue gas is complex in composition and contains multiple pollutants, especially a high concentration of SO2, and even after desulfurization, there is still 10-30 mg / Nm 3 of SO2 in the flue gas. Although the initial activity of non-noble metal catalysts is good, in the atmosphere containing trace SO2, the active component gradually reacts with SO2 to form sulfates over time, and the activity of the catalyst gradually decreases, and the sulfates formed on the surface of the catalyst can only be decomposed below 600℃, which is difficult to regenerate at such a high temperature in industry. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application provides a molecular sieve-based extruded honeycomb catalyst capable of simultaneously catalyzing NH3-SCR reaction of NO and CO oxidation reaction and a preparation method thereof. The catalyst has both catalytic activities, and can restore activity by low-temperature reduction regeneration after poisoning and deactivation in an atmosphere containing SO2, and can be used for simultaneous removal of NO and CO in sulfur-containing fixed source flue gas.

[0005] According to one aspect of the present application, a molecular sieve catalyst is provided, which is based on a molecular sieve-based honeycomb ceramic, and a transition metal composite oxide is loaded on the substrate.

[0006] The transition metal in the transition metal composite oxide is selected from at least two of copper, cerium, manganese and iron.

[0007] Optionally, the molecular sieve-based honeycomb ceramic has a plurality of parallel channels, the channels have a pore size of 2-8 mm, and the channel walls have a thickness of 0.5-1 mm.

[0008] In the matrix, 60-75% of the molecular sieve, 5-10% of SiO2, and 2-5% of glass fiber are included by mass of the molecular sieve catalyst.

[0009] Optionally, the molecular sieve is selected from one of FER-type molecular sieve, MFI-type molecular sieve, or BEA-type molecular sieve.

[0010] Optionally, the loading amount of the transition metal composite oxide accounts for 15-25% of the mass of the molecular sieve catalyst.

[0011] The molar ratio of any two transition metal atoms in the transition metal composite oxide is 1:4-1:1.

[0012] According to one aspect of the present application, a preparation method of the above-mentioned molecular sieve catalyst is provided, comprising the following steps:

[0013] a) mixing and kneading raw materials containing a molecular sieve, a plasticizer, deionized water, a silicone resin emulsion, palm oil, and glycerol; after kneading, adding glass fiber, sealing and aging to obtain a molecular sieve catalyst mud;

[0014] b) vacuuming the molecular sieve catalyst mud, repeatedly vacuuming 5-10 times, sealing and aging to obtain a molecular sieve catalyst mud section; extruding, microwaving, drying, and calcining the molecular sieve catalyst mud section to obtain the molecular sieve catalyst;

[0015] c) immersing the molecular sieve catalyst in a mixed solution containing at least two transition metal precursors, drying and calcining after immersion to obtain the molecular sieve catalyst.

[0016] Optionally, in step a), the plasticizer is selected from one of methyl cellulose, carboxymethyl cellulose, and hydroxypropyl methyl cellulose.

[0017] The kneading time of the mixing and kneading is 3-6 hours.

[0018] The aging time of the aging is 24-48 hours.

[0019] Optionally, in step a), the kneading time of the mixing and kneading is selected from 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, or any value between any two of the above.

[0020] The aging time is selected from 28 hours, 30 hours, 32 hours, 35 hours, 37 hours, 40 hours, 42 hours, 44 hours, 45 hours, 46 hours, or any value between any two of the above.

[0021] Optionally, the amount of plasticizer added is 2% to 6%, the amount of silicone resin emulsion added is 10% to 20%, the amount of glass fiber added is 2% to 6%, the amount of palm oil added is 2% to 6%, the amount of glycerol added is 1% to 3%, and the amount of deionized water added is 30% to 50%, based on the mass of the molecular sieve.

[0022] The water content of the molecular sieve catalyst mud is 25% to 30%.

[0023] Optionally, in step b), the vacuum degree of the vacuum mud conditioning is -0.08 to -0.095 MPa.

[0024] The aging time is 24 to 48 hours.

[0025] The diameter of the molecular sieve catalyst mud segment is 50 mm.

[0026] Optionally, in step b), the aging time is selected from 28 hours, 30 hours, 32 hours, 35 hours, 37 hours, 40 hours, 42 hours, 44 hours, 45 hours, 46 hours, or any value between any two of the above.

[0027] Optionally, in step b), the extruder used in the extrusion is selected from one of a plunger extruder, a continuous screw extruder, or a double screw extruder.

[0028] The microwave power is 500 w to 1000 w, and the microwave time is 3 to 5 minutes.

[0029] The drying temperature is 100 to 120°C, and the drying time is 8 to 12 hours.

[0030] The calcination temperature is 500 to 700°C, and the calcination time is 4 to 6 hours.

[0031] Optionally, in step b), the microwave power is selected from 500 w to 1000 w, or any value between any two of the above; and the microwave time is selected from 3.5 minutes, 3.8 minutes, 4 minutes, 4.2 minutes, 4.5 minutes, 4.8 minutes, or any value between any two of the above.

[0032] The calcination temperature of the calcination is selected from 520℃, 550℃, 570℃, 580℃, 600℃, 620℃, 650℃, 670℃, 690℃, or any value between any two of the above; the calcination time is selected from 4.2 hours, 4.5 hours, 4.7 hours, 4.9 hours, 5 hours, 5.3 hours, 5.5 hours, 5.8 hours, or any value between any two of the above.

[0033] Optionally, in step c), the impregnation time of the impregnation is 1 minute to 5 minutes.

[0034] The calcination temperature of the calcination is 500℃, and the calcination time is 2 to 4 hours.

[0035] Optionally, in step c), the calcination temperature of the calcination is selected from, or any value between any two of the above; the calcination time is selected from 2.2 hours, 2.5 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, or any value between any two of the above.

[0036] Optionally, the transition metal precursor is selected from at least one of nitrate, acetate of transition metal; the concentration of metal cation in the mixed solution is 1 mol / L to 5 mol / L.

[0037] According to one aspect of the present application, the application provides a use of the above-mentioned molecular sieve catalyst or the molecular sieve catalyst prepared by the above-mentioned preparation method in simultaneously catalyzing the reaction of selective reduction of nitrogen oxides by ammonia and the reaction of oxidation of carbon monoxide.

[0038] Optionally, a mixed gas containing nitrogen oxides, carbon monoxide, oxygen and ammonia is introduced into a reactor containing the molecular sieve catalyst for reaction; the reaction conditions are as follows: the volume space velocity is 2000 to 12000 h -1 -1, and the temperature is 150 to 500℃.

[0039] Optionally, the volume space velocity is 4000 to 6000 h -1 -1, and the temperature is 200 to 300℃.

[0040] Optionally, the volume space velocity is selected from 2500 h -1 , 3000 h -1 , 3500 h -1 , 5000 h -1 , 5500 h -1 , 6500 h -1 , 7000 h -1 , 7500 h -1 , 8000 h -1 , 8500 h -1 , 9000 h -1 , 9500 h-1 , 10000h -1 , 10500h -1 , 11000h -1 , or any value between any two of the aforementioned values; the temperature is selected from 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, or any value between any two of the aforementioned values.

[0041] Optionally, after the molecular sieve catalyst is poisoned by SO2 sulfuration, the molecular sieve catalyst is regenerated by reduction in a reducing gas, the reducing gas is a hydrogen-nitrogen mixed gas, the H2 concentration in the hydrogen-nitrogen mixed gas is 5% to 10%, and the reduction temperature is 250 to 400°C.

[0042] Optionally, the reduction temperature is 280°C, 300°C, 320°C, 350°C, 370°C, 390°C, or any value between any two of the aforementioned values.

[0043] As an embodiment of the present application, a preparation method of a molecular sieve catalyst is provided, comprising the following steps:

[0044] a) After dry mixing of the molecular sieve and the plasticizer, deionized water, silicone resin emulsion, palm oil, glycerol, and glass fiber are added for mixing and kneading; after kneading, the mixture is sealed and aged to obtain a molecular sieve catalyst mud;

[0045] b) The molecular sieve catalyst mud is subjected to vacuum mud conditioning, and after repeated 5 to 10 times of vacuum mud conditioning, the mud segment is sealed and aged to obtain a molecular sieve catalyst mud segment; the molecular sieve catalyst mud segment is extruded, subjected to microwave treatment, dried, and calcined to obtain a molecular sieve catalyst;

[0046] c) The molecular sieve catalyst is immersed in a mixed solution containing at least two transition metal precursors, and after immersion, the catalyst is dried and calcined to obtain the molecular sieve catalyst.

[0047] The present application comprises the following beneficial effects:

[0048] The extruded molecular sieve has a regular pore structure, and can realize simultaneous catalytic removal of NO and CO on the same catalytic bed, and the catalyst has good catalytic activity for removal of NO and CO at low temperature; the catalyst has good regenerability, and after the catalyst poisoned by SO2 is reduced by hydrogen at 280 to 400°C, the adsorbed SO2 on the surface of the catalyst can be removed, and the activity of the catalyst is restored, and the removal efficiency of NO and CO after regeneration can simultaneously reach more than 90%. BRIEF DESCRIPTION OF DRAWINGS

[0049] Figure 1 The NOx conversion rate and the CO conversion rate of the extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst prepared in Example 1 change with the inlet gas temperature.

[0050] Figure 2 NOxconversion and CO conversion curves of the extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst prepared for Example 2 as a function of inlet gas temperature.

[0051] Figure 3 NOxconversion and CO conversion curves of the extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst prepared for Example 3 as a function of inlet gas temperature.

[0052] Figure 4 NOxconversion and CO conversion curves of the extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst prepared for Example 4 as a function of inlet gas temperature.

[0053] Figure 5 NOxconversion and CO conversion curves of the extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst prepared for Example 5 as a function of inlet gas temperature.

[0054] Figure 6 NOxconversion and CO conversion curves of the extruded honeycomb simultaneous denitration and CO removal molecular sieve catalyst prepared for Example 1 as a function of inlet gas temperature after SO2sulfuration and after reduction regeneration. DETAILED DESCRIPTION

[0055] The present application will be described in detail below with reference to the examples, but the present application is not limited to these examples.

[0056] In the examples of the present application, the raw materials were purchased through commercial channels unless otherwise specified. The test methods were all conventional methods unless otherwise specified, and the instrument settings were all recommended settings of the manufacturers.

[0057] Among them, the FER type molecular sieve was purchased from Tianjin Nankai University; the ZSM-5 molecular sieve was purchased from Oss Catalyst Materials (Dalian) Co., Ltd.; and the methyl silicone resin emulsion was purchased from Hubei Sihai Chemical Factory.

[0058] In the examples of the present application, the denitration efficiency and the CO removal efficiency were calculated as follows:

[0059] Among them, NOx out is the outlet concentration of nitrogen oxides, NOx in is the inlet concentration of nitrogen oxides.

[0060] Among them, CO out is the outlet concentration of carbon monoxide, CO in is the inlet concentration of nitrogen oxides.

[0061] Example 1

[0062] Weigh 800g of FER molecular sieve and 32g of hydroxypropyl methylcellulose and add them to a kneader for dry mixing. After 30 minutes, add 160g of methyl silicone resin emulsion, 32g of palm oil, 16g of glycerol, 32g of glass fiber, and 400g of deionized water. Knead for 2 hours until the material is homogeneous, obtaining a molecular sieve catalyst slurry with a moisture content of 30%. After aging this molecular sieve catalyst slurry for 24 hours, begin vacuum kneading at a vacuum degree of -0.09 MPa. After kneading, let the slurry sit for 24 hours, then extrude it through a multi-hole die using a hydraulic piston extruder to form a honeycomb structure. The die specifications are as follows:

[0063] Cross-sectional dimensions (mm 2 )]]> Number of holes Hole width (mm) Inner wall thickness (mm) Outer wall thickness (mm) 22.3×22.3 5×5 3.3 0.9 1.1

[0064] The extruded honeycomb structure was dried in a microwave oven at 750W for 5 minutes for rapid shaping, and then transferred to a drying oven at 100℃ for 12 hours to obtain a dried green body. It was then cut into small segments with a length of 3cm and calcined in a muffle furnace at 600℃ for 4 hours to obtain a molecular sieve-based honeycomb ceramic structure.

[0065] Weigh 20g Cu(NO3)2·3H2O and 35.9g Ce(NO3)3·6H2O, add 30g deionized water to prepare a mixed solution. Add the above solution to a small beaker, then immerse the sintered molecular sieve-based honeycomb ceramic structure in the solution for 60 seconds, remove it, quickly dry it with hot air, and calcine it in a muffle furnace at 500℃ for 2 hours to obtain an extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal.

[0066] The catalyst sample was loaded into the reactor. The reaction atmosphere was: 500ppm NO + 500ppm NH3 + 6000ppm CO + 10% O2 + N2. The feed gas flow rate was adjusted to achieve a volume hourly space velocity (VHSV) of 6000 h⁻¹. -1 The concentrations of NO, NO2, and CO at the inlet and outlet were measured at different temperatures to calculate the total NOx conversion rate and CO conversion rate, thus obtaining the denitrification efficiency and CO removal efficiency of the catalyst. Figure 1 The curves showing the NOx and CO conversion rates of the extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal prepared in Example 1 are shown as a function of inlet gas temperature.

[0067] Example 2

[0068] The preparation of the catalyst is basically the same as in Example 1, except that the die specifications used in the extrusion process are as follows:

[0069] Cross-sectional dimensions (mm 2 )]]> Number of holes Hole width (mm) Inner wall thickness (mm) Outer wall thickness (mm) 21.2×21.2 3×3 5.7 0.9 1.15

[0070] The catalyst activity evaluation conditions are the same as in Example 1. Figure 2The curves showing the NOx and CO conversion rates of the extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal prepared in Example 2 are shown as a function of inlet gas temperature.

[0071] Example 3

[0072] The preparation of the catalyst is basically the same as in Example 1, except that the die specifications used in the extrusion process are as follows:

[0073] Cross-sectional dimensions (mm 2 )]]> Number of holes Hole width (mm) Inner wall thickness (mm) Outer wall thickness (mm) 21.4×21.4 9×9 1.8 0.45 0.8

[0074] The catalyst activity evaluation conditions are the same as in Example 1. Figure 3 The curves showing the NOx and CO conversion rates of the extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal prepared in Example 3 are shown as changes in inlet gas temperature.

[0075] Example 4

[0076] Weigh 800g of ZSM-5 molecular sieve and 32g of hydroxypropyl methylcellulose and add them to a kneader for dry mixing. After 30 minutes, add 160g of methyl silicone resin emulsion, 32g of palm oil, 16g of glycerol, 32g of glass fiber, and 400g of deionized water. Knead for 2 hours until the material is homogeneous, obtaining a molecular sieve catalyst slurry with a moisture content of 30%. After aging this catalyst slurry for 24 hours, begin vacuum kneading at a vacuum degree of -0.09 MPa. After kneading, let the slurry stand for 24 hours, then extrude it through a porous die using a hydraulic piston extruder to form a honeycomb structure. The die specifications are as follows:

[0077] Cross-sectional dimensions (mm 2 )]]> Number of holes Hole width (mm) Inner wall thickness (mm) Outer wall thickness (mm) 22.3×22.3 5×5 3.3 0.9 1.1

[0078] The extruded honeycomb structure was quickly shaped by drying in a microwave oven at 500W for 5 minutes, then transferred to a drying oven and dried at 100℃ for 12 hours to obtain a dried green body. It was then cut into small segments with a length of 3cm and calcined in a muffle furnace at 500℃ for 4 hours to obtain a molecular sieve-based honeycomb ceramic structure.

[0079] Weigh 20g Cu(NO3)2·3H2O and 35.9g Ce(NO3)3·6H2O, add 30g deionized water to prepare a mixed solution. Add the above solution to a small beaker, then immerse the sintered molecular sieve-based honeycomb ceramic structure in the solution for 60 seconds, remove it, quickly dry it with hot air, and calcine it in a muffle furnace at 500℃ for 2 hours to obtain an extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal.

[0080] The catalyst activity evaluation conditions are the same as in Example 1. Figure 4 The curves showing the NOx and CO conversion rates of the extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal prepared in Example 4 are shown as a function of inlet gas temperature.

[0081] Example 5

[0082] The catalyst preparation was basically the same as in Example 4, except that in the impregnation solution step, 5g of Cu(NO3)2·3H2O and 35.9g of Ce(NO3)3·6H2O were weighed and mixed with 30g of deionized water to prepare a mixed solution. This solution was added to a small beaker, and then the sintered molecular sieve-based honeycomb ceramic structure was immersed in the solution for 60 seconds, removed, quickly dried with hot air, and calcined in a muffle furnace at 500℃ for 2 hours to obtain an extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal.

[0083] The catalyst activity evaluation conditions are the same as in Example 1. Figure 5 The curves showing the NOx and CO conversion rates of the extruded honeycomb molecular sieve catalyst for simultaneous denitration and CO removal prepared in Example 5 are shown as a function of inlet gas temperature.

[0084] Example 6

[0085] The catalyst was prepared in the same manner as in Example 1. Before the catalyst activity evaluation, it was sulfided at 250°C for 3 hours in a reaction atmosphere of 100 ppm SO2 + 10% O2 + N2, with a gas flow rate of 1.5 L / min. After sulfidation, the catalyst was cooled to 150°C and evaluated under the activity evaluation conditions of Example 1. After the evaluation experiment, the temperature was raised to 280°C, the reaction atmosphere was adjusted to 5% H2 + N2, and the gas flow rate was 0.75 L / min. The sulfided catalyst was reduced for 2 hours, and then cooled to 150°C for activity evaluation.

[0086] Figure 6 The curves show the NOx and CO conversion rates of the catalyst after sulfidation and reduction regeneration as a function of inlet gas temperature. Figure 6 It can be seen that after sulfidation, the activity of the catalyst decreases significantly compared with that of the fresh catalyst. After reduction treatment, the activity of the catalyst is restored. In the range of 200-250℃, the conversion rates of NO and CO can be restored to over 90%.

[0087] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for simultaneously catalyzing the selective reduction of nitrogen oxides by ammonia and the oxidation of carbon monoxide using a molecular sieve catalyst, characterized in that, A mixture of nitrogen oxides, carbon monoxide, oxygen, and ammonia is passed into a reactor containing the molecular sieve catalyst for reaction; the reaction conditions are: volume hourly space velocity (VHSV) of 2000–12000 h⁻¹. -1 The temperature is 150~500℃; The molecular sieve catalyst uses molecular sieve-based honeycomb ceramic as a matrix, and the matrix is ​​loaded with transition metal composite oxides. The transition metals in the transition metal composite oxide are Cu and Ce; The molecular sieve-based honeycomb ceramic has several parallel channels with a pore diameter of 2-8 mm and a wall thickness of 0.5-1 mm. The matrix comprises, by mass, 60% to 75% molecular sieve, 5% to 10% SiO2, and 2% to 5% glass fiber; The molecular sieve is selected from FER molecular sieve or ZSM-5 molecular sieve; The loading of the transition metal composite oxide accounts for 15% to 25% of the mass of the molecular sieve catalyst; The atomic molar ratio of Cu to Ce in the transition metal composite oxide is 1:4 to 1:

1.

2. The method according to claim 1, characterized in that, The method for preparing the molecular sieve includes the following steps: a) Mix and knead the raw materials containing molecular sieves, plasticizers, deionized water, silicone resin emulsion, palm oil, and glycerin; add glass fiber after kneading, seal and age to obtain molecular sieve catalyst slurry. b) Vacuum kneading of molecular sieve catalyst sludge is repeated 5 to 10 times and then sealed and aged to obtain molecular sieve catalyst sludge segments; the molecular sieve catalyst sludge segments are extruded, microwaved, dried and calcined to obtain molecular sieve catalyst. c) The molecular sieve catalyst is impregnated in a mixed solution containing Cu and Ce precursors, and then dried and calcined to obtain the molecular sieve catalyst.

3. The method according to claim 2, characterized in that, In step a), the plasticizer is selected from one of methylcellulose, carboxymethylcellulose, and hydroxypropyl methylcellulose; The kneading time for the mixture is 3 to 6 hours; The aging time for the aging process is 24 to 48 hours.

4. The method according to claim 2, characterized in that, In step a), based on the mass of the molecular sieve, the amount of plasticizer added is 2%~6%, the amount of silicone resin emulsion added is 10%~20%, the amount of glass fiber added is 2%~6%, the amount of palm oil added is 2%~6%, the amount of glycerin added is 1%~3%, and the amount of deionized water added is 30%~50%. The moisture content of the molecular sieve catalyst slurry is 25% to 30%.

5. The method according to claim 2, characterized in that, In step b), the vacuum degree of the vacuum plowing is -0.08 to -0.095 MPa; The aging time for the aging product is 24 to 48 hours; The diameter of the molecular sieve catalyst sludge segment is 50 mm.

6. The method according to claim 2, characterized in that, In step b), the extruder used for extrusion is selected from one of a plunger extruder, a continuous screw extruder, or a twin-screw extruder; The microwave power is 500W~1000W, and the microwave duration is 3~5 minutes; The drying temperature is 100~120℃, and the drying time is 8~12 hours; The roasting temperature is 500-700℃, and the roasting time is 4-6 hours.

7. The method according to claim 2, characterized in that, In step c), the immersion time is 1 minute to 5 minutes; The roasting temperature is 500~700℃, and the roasting time is 2~4 hours.

8. The method according to claim 2, characterized in that, In step c), the precursors of Cu and Ce are selected from at least one of Cu and Ce nitrates and acetates; the concentration of Cu and Ce ions in the mixed solution is 1 mol / L to 5 mol / L.

9. The method according to claim 1, characterized in that, Volumetric hourly space velocity (VHSV) is 4000~6000 h⁻¹ -1 The temperature is 200~300℃.

10. The method according to claim 1, characterized in that, After the molecular sieve catalyst is poisoned by SO2 sulfidation, it is reduced and regenerated in a reducing gas, which is a hydrogen-nitrogen mixture with a H2 volume concentration of 5% to 10% and a reduction temperature of 250 to 400°C.

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