Dual core-shell structure catalyst suitable for high-temperature flue gas denitration of gas turbine as well as preparation method and denitration method of dual core-shell structure catalyst

Abstract

The invention discloses a dual core-shell structure catalyst suitable for gas turbine high-temperature flue gas denitration and a preparation method and denitration method.The dual core-shell structure catalyst is of an X / Cu / SiO2 (at) SiO2 (at) MOR structure and comprises an inner core, a first layer shell and a second layer shell, the first layer shell covers the outer portion of the inner core, and the second layer shell covers the outer portion of the inner core. The first shell is coated with the first shell, the second shell is coated outside the first shell, the inner core is X / Cu / SiO2, the active component is a bimetal combination of X and Cu, and X is selected from at least one of In, Ce and Ni; the first-layer shell is amorphous SiO2 and is used for inhibiting agglomeration and sintering of the active components; and the second layer shell is an MOR molecular sieve containing # imgabs0 # acid site, and is used for enhancing the adsorption capacity of NH3 and inhibiting oxidation of NH3. According to the dual core-shell structure catalyst provided by the embodiment of the invention, efficient denitration performance is maintained in a high-temperature environment of 500-650 DEG C.

Description

Technical Field

[0001] The present invention relates to the field of denitration catalysts, and in particular to a double core-shell structure catalyst suitable for denitration of high-temperature flue gas from a gas turbine, a preparation method thereof, and a denitration method. Background Art

[0002] With the increasingly stringent environmental protection requirements, nitrogen oxides (NO x ) emission control has become a key technical challenge. As a highly efficient and clean power generation equipment, gas turbines have a high NO x Emissions mainly come from the combustion process. Although gas turbines have relatively low dust and sulfur dioxide (SO2) emissions, their NO x The emissions are high, especially in the context of increasingly stringent national environmental protection requirements, NO x Emission control technology faces higher requirements.

[0003] Currently, Selective Catalytic Reduction (SCR) technology is the primary method for denitrification of gas turbine exhaust. Traditional SCR denitrification catalysts are primarily based on vanadium-based catalysts (such as V2O5-WO3 / TiO2), which exhibit high denitrification efficiency in the temperature range of 300°C-400°C. However, gas turbine flue gas temperatures are typically high (450°C-650°C), and catalysts used in related technologies are prone to sintering and deactivation at high temperatures. Furthermore, the NH3 oxidation side reaction occurs, reducing denitrification efficiency. Summary of the Invention

[0004] The present invention aims to address at least one of the technical problems existing in the prior art. To this end, one objective of the present invention is to provide a dual-core-shell catalyst suitable for denitrification of high-temperature flue gas from gas turbines. This dual-core-shell catalyst, suitable for denitrification of high-temperature flue gas from gas turbines, can maintain high denitrification performance at high temperatures of 500°C to 650°C while effectively inhibiting excessive oxidation of NH3, thereby improving denitrification efficiency.

[0005] The invention also provides a preparation method of the double core-shell structure catalyst.

[0006] The present invention also proposes a method for denitrifying high-temperature flue gas from a gas turbine using a double core-shell structure catalyst.

[0007] According to the first embodiment of the present invention, a double core-shell structure catalyst suitable for high-temperature flue gas denitration of a gas turbine has an X / Cu / SiO2@SiO2@MOR structure. The double core-shell structure catalyst includes a core, a first shell, and a second shell. The first shell is coated on the outside of the core, and the second shell is coated on the outside of the first shell, wherein:

[0008] The core is X / Cu / SiO2, and the active component is a bimetallic combination of X and Cu, wherein X is selected from at least one of In, Ce, and Ni;

[0009] The first shell is amorphous SiO2, which is used to inhibit the agglomeration and sintering of active components;

[0010] The second shell contains Acidic MOR molecular sieves are used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3.

[0011] According to the double core-shell structure catalyst for high-temperature flue gas denitration of gas turbines according to the embodiment of the present invention, the amorphous SiO2 of the first shell structure is used to wrap the core, which can effectively inhibit the agglomeration and sintering of the active components in the core at high temperature, so that the double core-shell structure catalyst can maintain high efficiency denitration performance in a high temperature environment of 500℃-650℃; The acidic MOR molecular sieve is used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3, and can provide good thermal stability and anti-sintering performance, so that the double core-shell structure catalyst can maintain high efficiency denitrification performance in a high temperature environment of 500℃-650℃.

[0012] According to some embodiments of the present invention, the thickness of the first shell is 10-50 nm, preferably 20-30 nm.

[0013] According to some embodiments of the present invention, the silicon-aluminum ratio of the MOR molecular sieve is 10-50, preferably 15-30.

[0014] According to some embodiments of the present invention, the molar ratio of X to Cu is 1:1 to 1:3, preferably 1:1.5 to 1:2.5.

[0015] According to the second embodiment of the present invention, the preparation method of the dual core-shell structure catalyst comprises the following steps:

[0016] (1) The core is prepared by an impregnation method, the specific steps comprising:

[0017] dissolving Cu(NO3)2·3H2O and X(NO3)3·xH2O in deionized water to form a mixed solution; adding a gas-phase SiO2 carrier to the mixed solution, stirring uniformly, and then performing ultrasonic treatment; drying and calcining the treated mixture to obtain an X / Cu / SiO2 catalyst, wherein the X / Cu / SiO2 catalyst constitutes the core;

[0018] (2) Wrapping the first shell around the outer surface of the core by a sol-gel method, wrapping the amorphous SiO2 around X / Cu / SiO2 to form a single core-shell structure X / Cu / SiO2@SiO2, the specific steps comprising:

[0019] The X / Cu / SiO2 catalyst is dispersed in a solution containing ammonia water, anhydrous ethanol and hexadecyltrimethylammonium bromide; tetraethyl orthosilicate is added dropwise as a SiO2 precursor, stirred evenly, and then dried and calcined;

[0020] (3) Wrapping the second shell on the outside of the first shell by a hydrothermal method to form the double core-shell structure catalyst, the specific steps include:

[0021] The single core-shell structure X / Cu / SiO2@SiO2 was mixed with the precursor of the MOR molecular sieve and added into a reactor; the reaction was carried out at a temperature of 160°C for 3 days, and after the reaction was completed, the mixture was dried and calcined.

[0022] According to the preparation method of the double core-shell structure catalyst of the embodiment of the present invention, the double core-shell structure catalyst prepared by the preparation method is used to wrap the core by the amorphous SiO2 of the first shell structure, which can effectively inhibit the agglomeration and sintering of the active components in the core at high temperature, so that the double core-shell structure catalyst can maintain high efficiency denitration performance in a high temperature environment of 500℃-650℃; The acidic MOR molecular sieve is used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3, and can provide good thermal stability and anti-sintering performance, so that the double core-shell structure catalyst can maintain high efficiency denitrification performance in a high temperature environment of 500℃-650℃.

[0023] According to some embodiments of the present invention, in the step of preparing the inner core by impregnation, the molar ratio of X(NO3)3·xH2O to Cu(NO3)2·3H2O is 1:1 to 1:3, preferably 1:1.5 to 1:2.5.

[0024] According to some embodiments of the present invention, in the step of wrapping the first shell on the outside of the inner core by a sol-gel method, the amount of tetraethyl orthosilicate added is 10-50 wt %, preferably 20-30 wt %.

[0025] A method for denitrifying high-temperature flue gas from a gas turbine using a dual core-shell structure catalyst according to a third embodiment of the present invention comprises the following steps:

[0026] (1) placing the dual core-shell structure catalyst in a fixed bed reactor;

[0027] (2) Containing NO x The flue gas is introduced into the fixed bed reactor;

[0028] (3) In the fixed bed reactor, NO is converted to x Converted into N2 and H2O;

[0029] (4) The post-reaction gas is purified through the tail gas treatment device to ensure that the emission meets the standards.

[0030] According to the double core-shell structure catalyst of the embodiment of the present invention, a denitrification method for high-temperature flue gas of a gas turbine is carried out. The denitrification method can enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3, and can enable the double core-shell structure catalyst to maintain good thermal stability and anti-sintering performance, and maintain a high denitrification efficiency in a high-temperature environment of 500℃-650℃.

[0031] According to some embodiments of the present invention, the NO in the flue gas x The concentration of is 200ppm-500ppm, the concentration of NH3 is 100ppm-300ppm, and the concentration of O2 is 5%-18%.

[0032] According to some embodiments of the present invention, the operating conditions of the fixed bed reactor include: a space velocity of 5000h -1 -20000h -1 , the reaction temperature is 500℃-650℃, and the reaction humidity is 5%-18%.

[0033] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0035] Figure 1 is a schematic flow chart of a method for preparing a dual core-shell structure catalyst according to some embodiments of the present invention;

[0036] Figure 2 1 is a schematic flow chart of a method for denitrifying high-temperature flue gas from a gas turbine using a dual core-shell structure catalyst according to some embodiments of the present invention;

[0037] Figure 3 is the NO of the double core-shell structure catalyst according to Example 1 of the present invention x Schematic diagram of conversion rate;

[0038] Figure 4 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 1 of the present invention;

[0039] Figure 5 is the NO of the double core-shell structure catalyst according to Example 2 of the present invention x Schematic diagram of conversion rate;

[0040] Figure 6 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 2 of the present invention;

[0041] Figure 7 is the NO of the double core-shell structure catalyst according to Example 3 of the present invention x Schematic diagram of conversion rate;

[0042] Figure 8 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 3 of the present invention;

[0043] Figure 9 is the NO of the double core-shell structure catalyst according to Example 4 of the present invention x Schematic diagram of conversion rate;

[0044] Figure 10 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 4 of the present invention;

[0045] Figure 11 is the NO of the double core-shell structure catalyst according to Example 5 of the present invention x Schematic diagram of conversion rate;

[0046] Figure 12 Schematic diagram of the N2 selectivity of the dual core-shell structure catalyst according to Example 5 of the present invention;

[0047] Figure 13 is the NO of the double core-shell structure catalyst according to Example 6 of the present invention x Schematic diagram of conversion rate;

[0048] Figure 14 Schematic diagram of the N2 selectivity of the dual core-shell structure catalyst according to Example 6 of the present invention;

[0049] Figure 15 is the NO of the double core-shell structure catalyst according to Example 7 of the present invention x Schematic diagram of conversion rate;

[0050] Figure 16 Schematic diagram of the N2 selectivity of the dual core-shell structure catalyst according to Example 7 of the present invention;

[0051] Figure 17 is the NO of the double core-shell structure catalyst according to Example 8 of the present invention x Schematic diagram of conversion rate;

[0052] Figure 18 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 8 of the present invention;

[0053] Figure 19 is the NO of the double core-shell structure catalyst according to Example 9 of the present invention x Schematic diagram of conversion rate;

[0054] Figure 20 Schematic diagram of the N2 selectivity of the dual core-shell structure catalyst according to Example 9 of the present invention;

[0055] Figure 21 is the NO of the double core-shell structure catalyst according to Example 10 of the present invention x Schematic diagram of conversion rate;

[0056] Figure 22 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 10 of the present invention;

[0057] Figure 23 is the NO of the double core-shell structure catalyst according to Example 11 of the present invention x Schematic diagram of conversion rate;

[0058] Figure 24 Schematic diagram of the N2 selectivity of the double core-shell structure catalyst according to Example 11 of the present invention;

[0059] Figure 25 is the NO of the double core-shell structure catalyst according to Example 12 of the present invention x Schematic diagram of conversion rate;

[0060] Figure 26 Schematic diagram of the N2 selectivity of the dual core-shell structure catalyst according to Example 12 of the present invention;

[0061] Figure 27 is the NO of the shell-less structure catalyst of Comparative Example 1 x Schematic diagram of conversion rate;

[0062] Figure 28 Schematic diagram of the N2 selectivity of the shell-less structure catalyst of Comparative Example 1;

[0063] Figure 29 is the NO of the single core-shell structure catalyst of Comparative Example 2 x Schematic diagram of conversion rate;

[0064] Figure 30 Schematic diagram of the N2 selectivity of the single core-shell structure catalyst of Comparative Example 2;

[0065] Figure 31 is the NO of the single core-shell structure catalyst of Comparative Example 3 x Schematic diagram of conversion rate;

[0066] Figure 32 This is a schematic diagram of the N2 selectivity of the single core-shell structure catalyst of Comparative Example 3. DETAILED DESCRIPTION

[0067] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0068] Reference below Figure 1-Figure 2 A double core-shell structure catalyst suitable for denitrification of high-temperature flue gas from a gas turbine according to an embodiment of the present invention is described.

[0069] According to the first embodiment of the present invention, a dual core-shell structure catalyst suitable for high-temperature flue gas denitration of a gas turbine has an X / Cu / SiO2@SiO2@MOR structure. The dual core-shell structure catalyst includes a core, a first shell, and a second shell. The first shell is coated on the outside of the core, and the second shell is coated on the outside of the first shell.

[0070] The core is X / Cu / SiO2, and the active component is a bimetallic combination of X and Cu, where X is selected from at least one of In, Ce, and Ni. The active component in the core structure plays a major catalytic role. For example, X in the core of X / Cu / SiO2 is selected from at least one of In, Ce, and Ni. X can be one of In, Ce, and Ni, or multiple of In, Ce, and Ni. For example, the core can be In / Cu / SiO2, Ce / Cu / SiO2, Ni / Cu / SiO2, In / Ce / Cu / SiO2, In / Ce / Ni / Cu / SiO2, etc.

[0071] The first shell is amorphous SiO2, which is used to inhibit the agglomeration and sintering of the active components. The amorphous SiO2 easily wraps the core, facilitating the morphology control of the first shell and making the shell thickness more uniform.

[0072] The second shell contains The acidic MOR molecular sieve is used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3. MOR molecular sieve can enhance the adsorption capacity of NH3, effectively inhibit the oxidation side reaction of NH3, and provide good thermal stability and anti-sintering performance.

[0073] According to the double core-shell structure catalyst for high-temperature flue gas denitration of gas turbines according to the embodiment of the present invention, the amorphous SiO2 of the first shell structure is used to wrap the core, which can effectively inhibit the agglomeration and sintering of the active components in the core at high temperature, so that the double core-shell structure catalyst can maintain high efficiency denitration performance in a high temperature environment of 500℃-650℃; The acidic MOR molecular sieve is used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3, and can provide good thermal stability and anti-sintering performance, so that the double core-shell structure catalyst can maintain high efficiency denitrification performance in a high temperature environment of 500℃-650℃.

[0074] According to some embodiments of the present invention, the thickness of the first shell is 10-50 nm, preferably 20-30 nm.

[0075] For example, the thickness of the first shell can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, etc.; preferably, the thickness of the first shell can be 20 nm, 22 nm, 24 nm, 26 nm, 28 nm, 30 nm, etc. By adjusting the first shell to an appropriate thickness, it can effectively encapsulate the core and effectively inhibit the agglomeration and sintering of the active components at high temperatures. If the thickness of the first shell is too thick, the catalytic effect of the active components will be affected; if the thickness of the first shell is too thin, it will be difficult to stably encapsulate the core.

[0076] According to some embodiments of the present invention, the silicon-aluminum ratio of the MOR molecular sieve is 10-50, preferably 15-30.

[0077] For example, the silicon-aluminum ratio of the MOR molecular sieve can be 10, 15, 20, 25, 30, 35, 40, 45, 50, etc. The preferred silicon-aluminum ratio of the MOR molecular sieve can be 15, 20, 25, 30, etc. By selecting a MOR molecular sieve with an appropriate silicon-aluminum ratio, good thermal stability and sintering resistance can be provided.

[0078] According to some embodiments of the present invention, the molar ratio of X to Cu is 1:1 to 1:3, preferably 1:1.5 to 1:2.5.

[0079] For example, the molar ratio of X to Cu can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc.; the preferred molar ratio of X to Cu can be 1:1.5, 1:1.75, 1:2, 1:2.25, 1:2.5, etc. By adjusting the molar ratio of X to Cu to an appropriate ratio, a stable catalytic effect can be achieved. If the molar ratio of X to Cu is too high, the proportion of Cu is too small. At low Cu content, X exists in a dispersed state, and the catalytic activity is low. If the molar ratio of X to Cu is too low, the proportion of Cu is too large, and its reduction performance deteriorates, and the catalytic reaction cannot be effectively carried out.

[0080] According to the second embodiment of the present invention, the preparation method of the dual core-shell structure catalyst comprises the following steps:

[0081] (1) The kernel is prepared by an impregnation method, and the specific steps include:

[0082] Cu(NO3)2·3H2O and X(NO3)3·xH2O are dissolved in deionized water to form a mixed solution; a gas-phase SiO2 carrier is added to the mixed solution, stirred uniformly, and then subjected to ultrasonic treatment; the treated mixture is dried and calcined to obtain an X / Cu / SiO2 catalyst, wherein the X / Cu / SiO2 catalyst constitutes a core, wherein the calcination temperature is 550°C, which can remove metal ion impurities and cause them to be oxidized;

[0083] (2) Wrapping the first shell around the outer core by a sol-gel method, wrapping the amorphous SiO2 around X / Cu / SiO2, and forming a single core-shell structure X / Cu / SiO2@SiO2. The specific steps include:

[0084] The X / Cu / SiO2 catalyst is dispersed in a solution containing ammonia, anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB); tetraethyl orthosilicate (TEOS) is added dropwise as a SiO2 precursor, and the mixture is stirred evenly before drying and calcining. TEOS is added dropwise to the solution containing the X / Cu / SiO2 catalyst dispersed in ammonia, anhydrous ethanol, and CTAB, so that the SiO2 generated by the reaction is evenly coated on the surface of the X / Cu / SiO2 catalyst to form a first shell. The calcination temperature is 700°C, which can remove metal ion impurities and oxidize them. The concentration of the ammonia is 25%.

[0085] (3) Using a hydrothermal method to wrap a second shell around the outside of the first shell to form a double core-shell structure catalyst, the specific steps include:

[0086] The single core-shell structure X / Cu / SiO2@SiO2 is mixed with the precursor of the MOR molecular sieve and added to a reactor; the reaction is carried out at a temperature of 160°C for 3 days. After the reaction is completed, it is dried and calcined. The calcination temperature is 700°C, which can remove metal ion impurities and oxidize them.

[0087] According to the preparation method of the double core-shell structure catalyst of the embodiment of the present invention, the double core-shell structure catalyst prepared by the preparation method is used to wrap the core by the amorphous SiO2 of the first shell structure, which can effectively inhibit the agglomeration and sintering of the active components in the core at high temperature, so that the double core-shell structure catalyst can maintain high efficiency denitration performance in a high temperature environment of 500℃-650℃; The acidic MOR molecular sieve is used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3, and can provide good thermal stability and anti-sintering performance, so that the double core-shell structure catalyst can maintain high efficiency denitrification performance in a high temperature environment of 500℃-650℃.

[0088] According to some embodiments of the present invention, in the step of preparing the inner core by impregnation, the molar ratio of X(NO3)3·xH2O to Cu(NO3)2·3H2O is 1:1 to 1:3, preferably 1:1.5 to 1:2.5.

[0089] For example, the molar ratio of Cu(NO3)2·3H2O to X(NO3)3·xH2O can be 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc.; the preferred molar ratio of Cu(NO3)2·3H2O to X(NO3)3·xH2O can be 1:1.5, 1:1.75, 1:2, 1:2.25, 1:2.5, etc. By regulating the molar ratio of Cu(NO3)2·3H2O to X(NO3)3·xH2O, the molar ratio of X to Cu can be adjusted to an appropriate ratio, thereby achieving a stable catalytic effect.

[0090] According to some embodiments of the present invention, in the step of wrapping the first shell around the outer core by a sol-gel method, the amount of tetraethyl orthosilicate added is 10-50 wt %, preferably 20-30 wt %.

[0091] For example, the addition amount of tetraethyl orthosilicate can be 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, etc. The preferred addition amount of tetraethyl orthosilicate is 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, etc. By adjusting the addition amount of tetraethyl orthosilicate, the amount of SiO2 generated can be adjusted, thereby playing a role in adjusting the thickness of the first shell.

[0092] A method for denitrifying high-temperature flue gas from a gas turbine using a dual core-shell structure catalyst according to a third embodiment of the present invention comprises the following steps:

[0093] (1) placing a dual core-shell structure catalyst in a fixed bed reactor, wherein the dual core-shell structure catalyst has good thermal stability and anti-sintering performance;

[0094] (2) Containing NO x The flue gas is introduced into the fixed bed reactor, wherein the temperature of the flue gas is in the range of 500°C to 650°C;

[0095] (3) In a fixed bed reactor, NO is converted to x Converted into N2 and H2O, thus reducing the NO in the flue gas x Concentration decreases;

[0096] (4) The post-reaction gas is purified through the tail gas treatment device to ensure that the emission meets the standards and prevent air pollution.

[0097] According to the double core-shell structure catalyst of the embodiment of the present invention, a method for denitrifying high-temperature flue gas of a gas turbine is carried out. The double core-shell structure catalyst used in the denitrification method has good thermal stability and anti-sintering performance, can enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3, thereby achieving the purpose of flue gas denitrification. By using the double core-shell structure catalyst to carry out the denitrification method of high-temperature flue gas of a gas turbine, a high denitrification efficiency can be maintained in a high temperature environment of 500°C-650°C.

[0098] According to some embodiments of the present invention, NO in flue gas x The concentration of is 200ppm-500ppm, the concentration of NH3 is 100ppm-300ppm, and the concentration of O2 is 5%-18%.

[0099] For example, NO in flue gas x The concentration of NO can be 200ppm, 250ppm, 300ppm, 350ppm, 400ppm, 450ppm, 500ppm, etc.; the concentration of NH3 can be 100ppm, 150ppm, 200ppm, 250ppm, 300ppm, etc.; the concentration of O2 can be 5%, 7%, 10%, 12%, 15%, 18%, etc. By regulating the NO in flue gas x , NH3 and O2 concentrations, can maintain a high denitrification efficiency in a high temperature environment. x If the content is too high, the double core-shell structure catalyst will be difficult to completely remove NO. x If NO in the flue gas x If the content is too low, remove NOx If the NH3 content in the flue gas is too high, it will cause ammonia to escape and increase the risk of secondary pollution; if the NH3 content in the flue gas is too low, it will not be able to completely reduce NO x , resulting in a decrease in denitrification efficiency. O2 is the oxidant in the reaction. If the O2 content in the flue gas is too high, it will affect the utilization rate of NH3 and thus the denitrification effect; if the O2 content in the flue gas is too low, the reaction rate will slow down.

[0100] According to some embodiments of the present invention, the operating conditions of the fixed bed reactor include: a space velocity of 5000 h -1 -20000h -1 , the reaction temperature is 500℃-650℃, and the reaction humidity is 5%-18%.

[0101] For example, the airspeed can be 5000h -1 、10000h -1 、15000h -1 、20000h -1 The reaction temperature can be 500°C, 550°C, 600°C, 650°C, etc.; the reaction humidity can be 5%, 7%, 10%, 12%, 15%, 18%, etc. Temperatures of 500°C-650°C and humidities of 5%-18% are suitable for high-temperature flue gas from gas turbines. If the space velocity is too low, the surface area of ​​the dual core-shell catalyst will be underutilized, resulting in low reaction efficiency. If the space velocity is too high, the dual core-shell catalyst may be exposed to excessive flue gas interferences, reducing its activity and thus affecting denitration efficiency. It can also cause the dual core-shell catalyst to sinter or be damaged, shortening its service life.

[0102] Refer to the following Figure 3-32 Describe the NO removal performance of the double core-shell structure catalysts of some embodiments of the present invention and the catalysts of comparative examples under the conditions of high temperature flue gas denitration in gas turbines x Performance differences in conversion and N2 selectivity.

[0103] Example 1,

[0104] (1) Preparation of In / Cu / SiO2 catalyst

[0105] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)3·xH2O (wherein the molar ratio of In to Cu is 1:1). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain an In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0106] (2) Preparation of In / Cu / SiO2@SiO2 single core-shell structure catalyst

[0107] The In / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using a sol-gel method. The In / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added. The mixture was then ultrasonically treated for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours. It was then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and held for 4 hours to obtain an In / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0108] (III) Preparation of In / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0109] Mix the In / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 15). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final In / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0110] Example 2,

[0111] (1) Preparation of In / Cu / SiO2 catalyst

[0112] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)3·xH2O (wherein the molar ratio of In to Cu is 1:1). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain an In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0113] (2) Preparation of In / Cu / SiO2@SiO2 single core-shell structure catalyst

[0114] The In / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using a sol-gel method. The In / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added. The mixture was then ultrasonically treated for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours. It was then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and held for 4 hours to obtain an In / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0115] (III) Preparation of In / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0116] Mix the In / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 30). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final In / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0117] Example 3,

[0118] (1) Preparation of In / Cu / SiO2 catalyst

[0119] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)3·xH2O (wherein the molar ratio of In to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain an In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0120] (2) Preparation of In / Cu / SiO2@SiO2 single core-shell structure catalyst

[0121] The In / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using a sol-gel method. The In / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added. The mixture was then ultrasonically treated for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours. It was then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and held for 4 hours to obtain an In / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0122] (III) Preparation of In / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0123] Mix the In / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 15). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final In / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0124] Example 4,

[0125] (1) Preparation of In / Cu / SiO2 catalyst

[0126] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)3·xH2O (wherein the molar ratio of In to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain an In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0127] (2) Preparation of In / Cu / SiO2@SiO2 single core-shell structure catalyst

[0128] The In / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using a sol-gel method. The In / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added. The mixture was then ultrasonically treated for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours. It was then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and held for 4 hours to obtain an In / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0129] (III) Preparation of In / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0130] Mix the In / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 30). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final In / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0131] Example 5,

[0132] (1) Preparation of Ce / Cu / SiO2 catalyst

[0133] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ce(NO3)3·xH2O (wherein the molar ratio of Ce to Cu is 1:1). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ce / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0134] (2) Preparation of Ce / Cu / SiO2@SiO2 single core-shell structure catalyst

[0135] The Ce / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using the sol-gel method. The Ce / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added, and ultrasonic treatment was performed for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ce / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0136] (III) Preparation of Ce / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0137] Mix the Ce / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 15). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to the experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final Ce / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0138] Example 6,

[0139] (1) Preparation of Ce / Cu / SiO2 catalyst

[0140] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ce(NO3)3·xH2O (wherein the molar ratio of Ce to Cu is 1:1). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ce / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0141] (2) Preparation of Ce / Cu / SiO2@SiO2 single core-shell structure catalyst

[0142] The Ce / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using the sol-gel method. The Ce / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added, and ultrasonic treatment was performed for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ce / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0143] (III) Preparation of Ce / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0144] Mix the Ce / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 30). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and maintain for 4 hours to obtain the final Ce / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0145] Example 7,

[0146] (1) Preparation of Ce / Cu / SiO2 catalyst

[0147] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ce(NO3)3·xH2O (wherein the molar ratio of Ce to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ce / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0148] (2) Preparation of Ce / Cu / SiO2@SiO2 single core-shell structure catalyst

[0149] The Ce / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using the sol-gel method. The Ce / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added, and ultrasonic treatment was performed for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ce / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0150] (III) Preparation of Ce / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0151] Mix the Ce / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 15). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to the experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final Ce / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0152] Example 8,

[0153] (1) Preparation of Ce / Cu / SiO2 catalyst

[0154] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ce(NO3)3·xH2O (wherein the molar ratio of Ce to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ce / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0155] (2) Preparation of Ce / Cu / SiO2@SiO2 single core-shell structure catalyst

[0156] The Ce / Cu / SiO2 prepared in step (1) was used as the core material and the SiO2 shell was coated using the sol-gel method. The Ce / Cu / SiO2 catalyst was placed in a beaker, and appropriate amounts of deionized water, ammonia (25% concentration), anhydrous ethanol, and cetyltrimethylammonium bromide (CTAB) were added, and ultrasonic treatment was performed for 30 minutes. Tetraethyl orthosilicate (TEOS) was slowly added dropwise as a SiO2 precursor and stirred evenly. The mixture was placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product was placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ce / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0157] (III) Preparation of Ce / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0158] Mix the Ce / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 30). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and maintain for 4 hours to obtain the final Ce / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0159] Example 9,

[0160] (1) Preparation of Ni / Cu / SiO2 catalyst

[0161] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ni(NO3)3·xH2O (wherein the molar ratio of Ni to Cu is 1:1). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ni / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0162] (2) Preparation of Ni / Cu / SiO2@SiO2 single core-shell structure catalyst

[0163] The Ni / Cu / SiO2 prepared in step (1) is used as the core material, and the SiO2 shell is coated using the sol-gel method. The Ni / Cu / SiO2 catalyst is placed in a beaker, and appropriate amounts of deionized water, ammonia (concentration of 25%), anhydrous ethanol and cetyltrimethylammonium bromide (CTAB) are added, and ultrasonic treatment is carried out for 30 minutes. Tetraethyl orthosilicate (TEOS) is slowly added dropwise as a SiO2 precursor and stirred evenly. The mixed solution is placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product is placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ni / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0164] (III) Preparation of Ni / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0165] Mix the Ni / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 15). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final Ni / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0166] Example 10,

[0167] (1) Preparation of Ni / Cu / SiO2 catalyst

[0168] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ni(NO3)3·xH2O (wherein the molar ratio of Ni to Cu is 1:1). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ni / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0169] (2) Preparation of Ni / Cu / SiO2@SiO2 single core-shell structure catalyst

[0170] The Ni / Cu / SiO2 prepared in step (1) is used as the core material, and the SiO2 shell is coated using the sol-gel method. The Ni / Cu / SiO2 catalyst is placed in a beaker, and appropriate amounts of deionized water, ammonia (concentration of 25%), anhydrous ethanol and cetyltrimethylammonium bromide (CTAB) are added, and ultrasonic treatment is carried out for 30 minutes. Tetraethyl orthosilicate (TEOS) is slowly added dropwise as a SiO2 precursor and stirred evenly. The mixed solution is placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product is placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ni / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0171] (III) Preparation of Ni / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0172] Mix the Ni / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 30). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final Ni / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0173] Example 11,

[0174] (1) Preparation of Ni / Cu / SiO2 catalyst

[0175] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ni(NO3)3·xH2O (wherein the molar ratio of Ni to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ni / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0176] (2) Preparation of Ni / Cu / SiO2@SiO2 single core-shell structure catalyst

[0177] The Ni / Cu / SiO2 prepared in step (1) is used as the core material, and the SiO2 shell is coated using the sol-gel method. The Ni / Cu / SiO2 catalyst is placed in a beaker, and appropriate amounts of deionized water, ammonia (concentration of 25%), anhydrous ethanol and cetyltrimethylammonium bromide (CTAB) are added, and ultrasonic treatment is carried out for 30 minutes. Tetraethyl orthosilicate (TEOS) is slowly added dropwise as a SiO2 precursor and stirred evenly. The mixed solution is placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product is placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ni / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0178] (III) Preparation of Ni / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0179] Mix the Ni / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 15). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final Ni / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0180] Example 12,

[0181] (1) Preparation of Ni / Cu / SiO2 catalyst

[0182] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and Ni(NO3)3·xH2O (wherein the molar ratio of Ni to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain a Ni / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0183] (2) Preparation of Ni / Cu / SiO2@SiO2 single core-shell structure catalyst

[0184] The Ni / Cu / SiO2 prepared in step (1) is used as the core material, and the SiO2 shell is coated using the sol-gel method. The Ni / Cu / SiO2 catalyst is placed in a beaker, and appropriate amounts of deionized water, ammonia (concentration of 25%), anhydrous ethanol and cetyltrimethylammonium bromide (CTAB) are added, and ultrasonic treatment is carried out for 30 minutes. Tetraethyl orthosilicate (TEOS) is slowly added dropwise as a SiO2 precursor and stirred evenly. The mixed solution is placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product is placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain a Ni / Cu / SiO2@SiO2 single core-shell structure catalyst. The thickness of the SiO2 shell can be controlled by adjusting the amount of TEOS added.

[0185] (III) Preparation of Ni / Cu / SiO2@SiO2@MOR dual core-shell structure catalyst

[0186] Mix the Ni / Cu / SiO2@SiO2 prepared in step (2) with a precursor of MOR molecular sieve (wherein Si / Al is 30). Place the mixture in a reactor and react at 180°C for 3 days. The specific time is adjusted according to experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and hold for 4 hours to obtain the final Ni / Cu / SiO2@SiO2@MOR double core-shell structure catalyst.

[0187] Comparative Example 1,

[0188] Preparation of the In / Cu / SiO2 catalyst: Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)3·xH2O (where the molar ratio of In to Cu is 1:2). Dissolve these compounds in deionized water and stir thoroughly to dissolve them completely. Add the vapor-phase SiO2 carrier to the solution and continue stirring to ensure uniform dispersion. The mixture is stirred at 75°C for 6 hours and then sonicated for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed several times with deionized water to remove impurities. The resulting product is then dried in an oven at 110°C for 12 hours. The dried sample is calcined in a muffle furnace at 550°C for 5 hours to obtain the In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0189] Comparative Example 2,

[0190] (1) Preparation of In / Cu / SiO2 catalyst

[0191] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)2·xH2O (wherein the molar ratio of In to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain an In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0192] (2) Preparation of In / Cu / SiO2@SiO2 single core-shell structure catalyst

[0193] The In / Cu / SiO2 prepared in step (1) is used as the core material, and the SiO2 shell is wrapped by the sol-gel method. The In / Cu / SiO2 catalyst is placed in a beaker, and appropriate amounts of deionized water, ammonia water (concentration of 25%), anhydrous ethanol and hexadecyltrimethylammonium bromide (CTAB) are added, and ultrasonic treatment is carried out for 30 minutes. Tetraethyl orthosilicate (TEOS) is slowly added dropwise as a precursor of SiO2 and stirred evenly. The mixed solution is placed in a magnetic stirrer and stirred at 30°C for 6 hours, then centrifuged and washed with deionized water and anhydrous ethanol. The product is placed in an oven and dried at 120°C for 12 hours, then heated to 700°C in a muffle furnace at a heating rate of 4°C / min and maintained for 4 hours to obtain an In / Cu / SiO2@SiO2 single core-shell structure catalyst.

[0194] Comparative Example 3,

[0195] (1) Preparation of In / Cu / SiO2 catalyst

[0196] Accurately weigh appropriate amounts of Cu(NO3)2·3H2O and In(NO3)3·xH2O (wherein the molar ratio of In to Cu is 1:2). Dissolve the above compounds in deionized water and stir evenly to dissolve them completely. Add the gas-phase SiO2 carrier to the above solution and continue stirring to ensure that the carrier is evenly dispersed. Stir the mixture at 75°C for 6 hours and then ultrasonicate for 2 hours to enhance mixing uniformity. The treated mixture is centrifuged and rinsed with deionized water several times to remove impurities. The resulting product is then placed in an oven and dried at 110°C for 12 hours. The dried sample is placed in a muffle furnace and calcined at 550°C for 5 hours to obtain an In / Cu / SiO2 catalyst. Before performance testing, the sample is ground and sieved to 40-60 mesh.

[0197] (2) Preparation of In / Cu / SiO2@MOR single core-shell structure catalyst

[0198] The In / Cu / SiO2 prepared in step (1) is used as the core material and mixed with the precursor of the MOR molecular sieve (wherein Si / Al is 15). The mixture is placed in a reactor and reacted at 180°C for 3 days. The specific time is adjusted according to the experimental requirements. After the reaction is completed, the product is thoroughly washed to remove unreacted precursors and impurities. Dry at 100°C for more than 12 hours, then heat to 700°C in a muffle furnace at a heating rate of 4°C / min and maintain for 4 hours to obtain the final In / Cu / SiO2@MOR single core-shell structure catalyst.

[0199] Reference Figure 3-32, the nitrogen oxide conversion rate and nitrogen selectivity of the four groups of Examples 1 to 4 all performed excellently, especially between 400°C and 650°C. Among them, the third group reached a peak of 98% at 550°C, and the nitrogen selectivity was stable at more than 95%. The nitrogen oxide conversion rate and nitrogen selectivity of the four groups of Examples 5 to 8 performed poorly, with the peak appearing between 400°C and 500°C, the nitrogen oxide conversion rate being around 70%, and the nitrogen selectivity being stable at around 80%. The nitrogen oxide conversion rate and nitrogen selectivity of the four groups of Examples 9 to 12 performed generally, with the peak appearing between 400°C and 500°C, the nitrogen oxide conversion rate being around 75%, and the nitrogen selectivity being stable at around 70%. Comparison of the catalyst sample prepared in Example 3 revealed the best performance. Three comparative examples were prepared for Example 3. Comparative Example 1 exhibited poor nitrogen oxide conversion and nitrogen selectivity, reaching a peak of 62.1% at 350°C and a stable nitrogen selectivity of 62%. Comparative Example 2 exhibited moderate nitrogen oxide conversion and nitrogen selectivity, reaching a peak of 79.2% at 400°C and a stable nitrogen selectivity of 76%. Comparative Example 3 exhibited excellent nitrogen oxide conversion and nitrogen selectivity, but still lower than the catalyst sample in Example 3, reaching a peak of 88.3% at 350°C and a stable nitrogen selectivity of 98%. The above examples and comparative examples demonstrate that the dual core-shell structure catalyst in Example 3 exhibits the best performance. Through the above-described specific embodiments, the present invention provides a dual core-shell structure catalyst suitable for high-temperature flue gas denitration in gas turbines, as well as its preparation method and denitration method, which effectively address the shortcomings of the related art and possess significant application prospects.

[0200] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0201] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A double core-shell structure catalyst suitable for denitrification of high-temperature flue gas from gas turbines, characterized in that: The double core-shell structure catalyst has an X / Cu / SiO2@SiO2@MOR structure, and includes a core, a first shell, and a second shell, wherein the first shell is coated on the outside of the core, and the second shell is coated on the outside of the first shell, wherein: The core is X / Cu / SiO2, and the active component is a bimetallic combination of X and Cu, wherein X is selected from at least one of In, Ce, and Ni; The first shell is amorphous SiO2, which is used to inhibit the agglomeration and sintering of active components; The second shell contains Acidic MOR molecular sieves are used to enhance the adsorption capacity of NH3 and inhibit the oxidation of NH3.

2. The dual core-shell structure catalyst according to claim 1, characterized in that The thickness of the first shell is 10-50 nm, preferably 20-30 nm.

3. The dual core-shell structure catalyst according to claim 1, characterized in that The silicon-aluminum ratio of the MOR molecular sieve is 10-50, preferably 15-30.

4. The dual core-shell structure catalyst according to claim 1, characterized in that The molar ratio of X to Cu is 1:1 to 1:3, preferably 1:1.5 to 1:2.

5.

5. A method for preparing a dual core-shell structure catalyst according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) The core is prepared by an impregnation method, the specific steps comprising: dissolving Cu(NO3)2·3H2O and X(NO3)3·xH2O in deionized water to form a mixed solution; adding a gas-phase SiO2 carrier to the mixed solution, stirring uniformly, and then performing ultrasonic treatment; drying and calcining the treated mixture to obtain an X / Cu / SiO2 catalyst, wherein the X / Cu / SiO2 catalyst constitutes the core; (2) Wrapping the first shell around the outer surface of the core by a sol-gel method, wrapping the amorphous SiO2 around X / Cu / SiO2 to form a single core-shell structure X / Cu / SiO2@SiO2, the specific steps comprising: The X / Cu / SiO2 catalyst is dispersed in a solution containing ammonia water, anhydrous ethanol and hexadecyltrimethylammonium bromide; tetraethyl orthosilicate is added dropwise as a SiO2 precursor, stirred evenly, and then dried and calcined; (3) Wrapping the second shell on the outside of the first shell by a hydrothermal method to form the double core-shell structure catalyst, the specific steps include: The single core-shell structure X / Cu / SiO2@SiO2 was mixed with the precursor of the MOR molecular sieve and added into a reactor; the reaction was carried out at a temperature of 160°C for 3 days, and after the reaction was completed, the mixture was dried and calcined.

6. The method for preparing a dual core-shell structure catalyst according to claim 5, characterized in that: In the step of preparing the inner core by impregnation, the molar ratio of X(NO3)3·xH2O to Cu(NO3)2·3H2O is 1:1 to 1:3, preferably 1:1.5 to 1:2.

5.

7. The method for preparing a dual core-shell structure catalyst according to claim 5, wherein: In the step of wrapping the first shell on the outside of the inner core by a sol-gel method, the added amount of tetraethyl orthosilicate is 10-50 wt %, preferably 20-30 wt %.

8. A method for denitrifying high-temperature flue gas from a gas turbine using the dual core-shell structure catalyst according to any one of claims 1 to 4, characterized in that: The denitration method comprises the following steps: (1) placing the dual core-shell structure catalyst in a fixed bed reactor; (2) Containing NO x The flue gas is introduced into the fixed bed reactor; (3) In the fixed bed reactor, NO is converted to x Converted into N2 and H2O; (4) The post-reaction gas is purified through the tail gas treatment device to ensure that the emission meets the standards.

9. The denitration method according to claim 8, characterized in that: The NO in the flue gas x The concentration of is 200ppm-500ppm, the concentration of NH3 is 100ppm-300ppm, and the concentration of O2 is 5%-18%.

10. The denitration method according to claim 8, characterized in that: The operating conditions of the fixed bed reactor include: a space velocity of 5000 h -1 -20000h -1 , the reaction temperature is 500℃-650℃, and the reaction humidity is 5%-18%.

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