A method for preparing and using an ethane catalytic combustion catalyst

Abstract

The application relates to the technical field of catalytic combustion of ethane, and discloses a preparation method and application of a catalytic combustion catalyst for ethane, which comprises the following steps: (1) dissolving chloroplatinic acid, a transition metal M1 nitrate and a rare earth metal M2 nitrate in water to obtain a mixed salt solution; and dripping the mixed salt solution into a molecular sieve carrier to perform impregnation, so as to obtain a solid A; (2) pre-drying the solid A, and then continuously drying after temperature rising, so as to obtain a powder B; and (3) performing aerobic calcination on the powder B, so as to obtain a catalyst; the catalyst is PtM1M2 / S, wherein M1 is one or more of iron, cobalt, nickel, manganese and copper, M2 is one or more of cerium, lanthanum, scandium, yttrium and samarium, and S is a molecular sieve carrier. The rare earth metal and the transition metal are synergistically doped, a strong interaction is formed between the rare earth metal and the transition metal and the noble metal platinum, the activation of ethane can be effectively enhanced, the reaction temperature can be reduced, and the conversion rate and stability of ethane can be improved.

Description

Technical Field

[0001] This invention relates to the technical field of ethane catalytic combustion, and in particular to a method for preparing and applying an ethane catalytic combustion catalyst. Background Technology

[0002] Currently, liquid nitrogen cryogenic technology can remove C2 and higher carbon components from VOCs in exhaust gases, but C2 components cannot be completely removed. Among low-carbon alkanes, ethane is second only to methane in inertness and is difficult to activate. Regenerative thermal oxidation (RTO) or direct combustion (TO) can achieve milligram-level emissions of C2 components, but these methods have disadvantages such as high processing temperatures, high energy consumption, high operating costs, and significant safety hazards. Therefore, it is necessary to develop catalysts that can treat gaseous ethane through catalytic combustion (CO) at low temperatures.

[0003] Noble metal-based catalysts (such as Pt and Pd) typically exhibit excellent catalytic activity for the combustion of low-carbon alkanes at low temperatures. Patent CN1212889C discloses a catalytic combustion catalyst and its preparation method. This monolithic catalyst uses Pt or Pd as the active component, doped with a certain amount of alkaline earth metal oxides, with alumina as the catalyst support and cordierite as the substrate. However, its total organic hydrocarbon removal rate is below 95%, failing to achieve a non-methane total hydrocarbon content of no more than 20 mg / m³. 3 The emission standards are being discussed. Patent CN107208511A discloses a catalyst for oxidizing methane and ethane in natural gas engine exhaust. By loading a Pt / Pd bimetallic compound onto a molecular sieve containing heteroatoms, the ethane conversion rate can reach 100% at 400℃. However, this catalyst uses a Pt / Pd bimetallic component, resulting in high catalyst cost, and the high temperature required for 100% reaction leads to high energy consumption. The paper (Long Yu, Experimental Study on Low-Temperature Catalytic Reaction and Micro-combustion Characteristics of Ethane) uses 5% Pt / ZSM-5 for partial catalytic oxidation of ethane, but the ethane conversion rate is less than 95%, failing to meet emission standards.

[0004] Therefore, developing ethane catalytic combustion catalysts that are low in cost, simple in preparation method, high in low-temperature conversion rate, and high in stability presents certain challenges. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for preparing and applying an ethane catalytic combustion catalyst. This catalyst, through the synergistic doping of rare earth metals and transition metals, can effectively enhance the activation of ethane, reduce the reaction temperature, and increase the conversion rate of ethane. Furthermore, the introduction of the second / third metal can form a strong interaction with the noble metal platinum, inhibiting the aggregation of active components and increasing its dispersion while reducing the amount of Pt, thereby ensuring the density of active sites on the catalyst and improving the stability of the catalyst.

[0006] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a method for preparing an ethane catalytic combustion catalyst, comprising the following steps: (1) Dissolve chloroplatinic acid, transition metal M1 nitrate and rare earth metal M2 nitrate in water to obtain a mixed salt solution, wherein the molar ratio of M1 to M2 is 0.5-5:1; add the mixed salt solution dropwise onto a molecular sieve support for impregnation to obtain solid A; (2) After pre-drying solid A, heat it up and continue drying to obtain powder B; (3) Powder B is calcined in an aerobic environment to obtain a catalyst; the catalyst is PtM1M2 / S, wherein M1 is one or more of iron, cobalt, nickel, manganese and copper, M2 is one or more of cerium, lanthanum, scandium, yttrium and samarium, and S is a molecular sieve support.

[0007] This invention constructs a Pt-rare earth-transition metal synergistic system by forming second / trimetallic active sites through doping with rare earth metals and transition metals. At the same time, it improves the dispersion of active components through process optimization, thereby increasing the number of active centers and effectively reducing the Pt loading.

[0008] Rare earth metals can promote the migration and activation of oxygen species on the catalyst surface, increasing the number of active oxygen species (lattice oxygen O). 2- Adsorbed oxygen O 2- The rare earth metals (such as α, β, and γ) migrate to the Pt surface, promoting deep activation of the CH bonds. Transition metals, through electron transfer, regulate the electron cloud density of the Pt surface, reducing the d-band center of Pt and enhancing its adsorption capacity for the CH bonds in ethane molecules. Simultaneously, they lower the dissociation barrier of the CH bonds, enabling efficient activation of ethane at low temperatures and significantly improving the low-temperature combustion activity of the catalyst. The activated hydrocarbon intermediates react rapidly with active oxygen species on the catalyst surface, gradually oxidizing to formaldehyde, formic acid, and other intermediates, ultimately further oxidizing to CO2 and H2O. During this process, the variable valence states of rare earth metals continuously replenish active oxygen, while transition metals maintain the catalytic activity of Pt through electron transfer, forming a cycle of oxygen species and electrons to ensure the continuous reaction. The generated CO2 and H2O, due to their weak interaction with the catalyst surface, rapidly desorb and detach from the catalyst surface, releasing active sites for the next round of reaction, thus achieving a catalytic cycle.

[0009] In the catalytic combustion reaction of ethane, Pt, as the core active center, is responsible for the adsorption and dissociation of CH bonds. The second / trimetallic components enhance the reaction kinetics through electronic regulation and oxygen species activation. The molecular sieve support provides an efficient mass transfer channel and a stable loading environment. The three work together to promote the low-temperature, efficient and stable catalytic combustion of ethane, solving the key problems of insufficient low-temperature activity and poor stability of traditional catalysts.

[0010] Preferably, the molar ratio of M1+M2:Pt in the mixed salt solution is 0.1-10:1; and the Pt loading in the catalyst is 0.1-1 wt%.

[0011] Preferably, S is MWW molecular sieve, MFI molecular sieve, MOR molecular sieve, FAU molecular sieve or BEA molecular sieve.

[0012] On the one hand, the molecular sieve support provides sufficient anchoring sites for Pt nanoparticles, enabling uniform Pt particle size dispersion and significantly increasing the number of active centers; on the other hand, its abundant pore structure enhances the adsorption and diffusion capacity of ethane molecules on the catalyst surface, shortens the contact distance between reactants and active centers, and improves the reaction kinetic rate.

[0013] Preferably, the dropping rate of the mixed salt solution is 0.1-1.0 mL / min; during impregnation, the mass ratio of the mixed salt solution to the molecular sieve support is 1-3:1.

[0014] By dripping a mixed salt solution onto a molecular sieve support, the metal precursor can be uniformly dispersed at the molecular level on the support surface and within the pores.

[0015] Preferably, the concentration of chloroplatinic acid in the mixed salt solution is 0.0017-0.0100 mol / L.

[0016] Preferably, the pre-drying is performed at 40-60 ℃ for 4-6 h; the continued drying is performed at 80-120 ℃ for 4-6 h.

[0017] First, the surface moisture of the carrier is slowly removed through pre-drying to avoid the collapse of the carrier pores caused by rapid dehydration. Then, the temperature is raised and drying continues to remove water inside the carrier pores and chemically bound water between metal ions and hydroxyl groups on the carrier surface. This also inhibits the migration and aggregation of metal precursors. After natural cooling to room temperature, powder B is obtained.

[0018] Preferably, the calcination is carried out by heating to 400-600℃ at a rate of 1-5℃ / min and maintaining the temperature for 3-6 hours.

[0019] Secondly, the present invention also provides an application of the catalyst prepared by the above preparation method in the catalytic combustion of ethane, wherein the raw gas is brought into contact with the catalyst to carry out a catalytic combustion reaction, and the raw gas includes ethane and oxygen.

[0020] Preferably, the reaction temperature of the catalytic combustion reaction is 150-500℃ and the reaction pressure is 0.1-0.5 MPa; more preferably, the reaction temperature of the catalytic combustion reaction is 150-350℃ and the reaction pressure is 0.1-0.5 MPa.

[0021] Preferably, the ethane concentration in the feed gas is 1000-8000 ppm, the oxygen content is 2-10 vol%, and the remaining gas is nitrogen; the catalytic combustion reaction is carried out in a fixed-bed reactor, and the space velocity of the feed gas through the catalyst bed is 10000-100000 mL·g. -1 ·h -1 .

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) Ethane catalytic combustion catalyst has a large specific surface area, which can promote the dispersion of active sites. Its rich pore structure can enhance the diffusion of ethane molecules, thereby improving the catalytic efficiency. (2) By introducing a second / trimetallic element, the electron cloud density of the Pt surface can be adjusted, the adsorption and dissociation ability of Pt on the CH bond in the ethane molecule can be enhanced, and the adsorption oxygen content on the Pt surface can be increased, thereby improving the low-temperature activity of the catalyst and the conversion efficiency of ethane. (3) The introduction of multi-metal components forms stable metal-metal and metal-support interactions, which can inhibit the sintering and loss of Pt nanoparticles in high-temperature reactions, thereby improving the stability of the catalyst. At the same time, it can effectively reduce the loading of Pt, thereby reducing the cost of catalyst preparation. (4) The catalyst preparation process described in this invention is simple and controllable, and can be mass-produced. Attached Figure Description

[0023] Figure 1 This is a graph showing the stability evaluation results of the PtMnSc / S-1 catalyst in Example 5; Figure 2 The image shows the infrared analysis of the tail gas components after the catalytic combustion of ethane using the PtCuCe / ZSM-5 catalyst in Example 1. Figure 3 The image shows the SEM-EDS image of the PtFeY / USY catalyst in Example 3. Detailed Implementation

[0024] The technical solution of the present invention will be illustrated below with specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0025] Example 1

[0026] (1) Weigh out 0.1325 g of chloroplatinic acid hexahydrate (2.56 × 10⁻⁶ g) and 0.1325 g of chloroplatinic acid hexahydrate (2.56 × 10⁻⁶ g) respectively. -4 0.0021 g copper nitrate trihydrate (8.53 × 10⁻⁶ mol) -6 0.0074 g of cerium nitrate hexahydrate (1.71 × 10⁻⁶ mol) and 0.0074 g of cerium nitrate hexahydrate (1.71 × 10⁻⁶ mol). -5 5 g of mixed salt solution was placed in a beaker and dissolved in deionized water to form a homogeneous and transparent solution, wherein Cu / Ce = 0.5 (molar ratio) and (Cu+Ce) / Pt = 0.1 (molar ratio). Then, 5 g of ZSM-5 molecular sieve was taken, and the mixed salt solution was added dropwise to the molecular sieve powder at a rate of 0.1 mL / min, while stirring the molecular sieve powder at a stirring speed of 100 r / min. After the addition was completed, solid A was obtained. (2) Solid A is spread on a petri dish with a layer thickness of ≤5mm. It is placed in a 40℃ oven for low-temperature pre-drying for 4h. Then the oven temperature is increased to 80℃ at a rate of 2℃ / min and dried for another 4h. After natural cooling to room temperature, powder B is obtained. (3) Powder B is transferred to a muffle furnace and calcined at 400°C for 3 h in an air atmosphere at a rate of 2°C / min. The obtained catalyst is pressed into tablets, crushed, and sieved to produce 40-60 mesh granular catalyst, namely PtCuCe / ZSM-5 supported catalyst, in which the Pt loading is 1 wt%.

[0027] Example 2

[0028] (1) Weigh out 0.0927 g of chloroplatinic acid hexahydrate (1.79 × 10⁻⁶ g) and 0.0927 g of chloroplatinic acid hexahydrate (1.79 × 10⁻⁶ g) respectively. -4 mol), 0.0521 g nickel nitrate hexahydrate (1.79 × 10⁻⁶ ...) -4 0.0775 g of lanthanum nitrate hexahydrate (1.79 × 10⁻⁶ mol) and 0.0775 g of lanthanum nitrate hexahydrate (1.79 × 10⁻⁶ mol). -4 6 g of mixed salt solution was placed in a beaker and dissolved in deionized water to form a homogeneous and transparent solution, wherein Ni / La = 1 (molar ratio) and (Ni+La) / Pt = 2 (molar ratio). Then, 5 g of MOR molecular sieve was taken, and the mixed salt solution was added dropwise to the molecular sieve powder at a rate of 0.3 mL / min, while stirring the molecular sieve powder at a stirring speed of 200 r / min. After the addition was completed, solid A was obtained. (2) Solid A was spread on a petri dish with a layer thickness of ≤5mm and placed in a 40℃ oven for low-temperature pre-drying for 4.5 h. Then the oven temperature was increased to 90℃ at a rate of 3℃ / min and dried for another 4.5 h. After natural cooling to room temperature, powder B was obtained. (3) Powder B is transferred to a muffle furnace and calcined at 450°C for 3.5 h in an air atmosphere at a rate of 2°C / min. The obtained catalyst is pressed into tablets, crushed, and sieved to produce granular catalysts of 40-60 mesh, namely PtNiLa / MOR supported catalysts, in which the Pt loading is 0.7 wt%.

[0029] Example 3

[0030] (1) Weigh out 0.0663 g of chloroplatinic acid hexahydrate (1.28 × 10⁻⁶ g) and 0.0663 g of chloroplatinic acid hexahydrate (1.28 × 10⁻⁶ g) respectively. -4 mol), 0.1378 g ferric nitrate nonahydrate (3.41 × 10⁻⁶ ...) -4 0.0163 g yttrium nitrate hexahydrate (1.71 × 10⁻⁶ mol) and 0.0163 g yttrium nitrate hexahydrate (1.71 × 10⁻⁶ mol). -4 mol) was placed in a beaker and dissolved in deionized water to form a homogeneous and transparent 8 g mixed salt solution, wherein Fe / Y = 2 (molar ratio) and (Fe+Y) / Pt = 4 (molar ratio); then, 5 g of USY molecular sieve was taken, and the mixed salt solution was added dropwise to the molecular sieve powder at a rate of 0.5 mL / min, while stirring the molecular sieve powder at a stirring speed of 300 r / min. After the dropwise addition was completed, solid A was obtained; (2) Solid A is spread on a petri dish with a layer thickness of ≤5mm. It is placed in a 50℃ oven for low-temperature pre-drying for 5h. Then the oven temperature is increased to 100℃ at a rate of 4℃ / min and dried for another 5h. After natural cooling to room temperature, powder B is obtained. (3) Powder B is transferred to a muffle furnace and calcined at 3 °C / min to 500 °C for 4 h in an air atmosphere. The obtained catalyst is pressed into tablets, crushed and sieved to make 40-60 mesh granular catalyst, namely PtFeY / USY supported catalyst, in which the Pt loading is 0.5 wt%.

[0031] Example 4

[0032] (1) Weigh out 0.0397 g of chloroplatinic acid hexahydrate (7.68 × 10⁻⁶ g) respectively. -5 mol), 0.1005 g cobalt nitrate hexahydrate (3.45 × 10⁻⁶ mol), -4 0.0512 g of samarium nitrate hexahydrate (1.15 × 10⁻⁶ mol) and 0.0512 g of samarium nitrate hexahydrate (1.15 × 10⁻⁶ mol). -410 g of mixed salt solution was placed in a beaker and dissolved in deionized water to form a homogeneous and transparent solution, wherein Co / Sm = 3 (molar ratio) and (Co+Sm) / Pt = 6 (molar ratio); then, 5 g of Beta molecular sieve was taken, and the mixed salt solution was added dropwise to the molecular sieve powder at a rate of 0.6 mL / min, while stirring the molecular sieve powder at a stirring speed of 400 r / min. After the addition was completed, solid A was obtained. (2) Solid A is spread on a petri dish with a layer thickness of ≤5mm. It is placed in a 60℃ oven for low-temperature pre-drying for 6h. Then the oven temperature is increased to 110℃ at a rate of 5℃ / min and dried for another 6h. After natural cooling to room temperature, powder B is obtained. (3) Powder B is transferred to a muffle furnace and calcined at 550°C for 5 h in an air atmosphere at a rate of 4°C / min. The obtained catalyst is pressed into tablets, crushed, and sieved to produce granular catalysts of 40-60 mesh, namely PtCoSm / Beta supported catalysts, wherein the Pt loading is 0.3 wt%.

[0033] Example 5

[0034] (1) Weigh out 0.0132 g of chloroplatinic acid hexahydrate (2.56 × 10⁻⁶ g) respectively. -5 0.0514 g manganese nitrate tetrahydrate (2.05 × 10⁻⁶ mol) -4 0.0173 g scandium nitrate hexahydrate (5.12 × 10⁻⁶ mol) and 0.0173 g scandium nitrate hexahydrate (5.12 × 10⁻⁶ mol). -5 15 g of mixed salt solution was placed in a beaker and dissolved in deionized water to form a homogeneous and transparent solution, wherein Mn / Sc = 4 (molar ratio) and (Mn+Sc) / Pt = 10 (molar ratio); then, 5 g of S-1 molecular sieve was taken, and the mixed salt solution was added dropwise to the molecular sieve powder at a rate of 1.0 mL / min, while stirring the molecular sieve powder at a stirring speed of 500 r / min. After the addition was completed, solid A was obtained. (2) Solid A is spread on a petri dish with a layer thickness of ≤5mm. It is placed in a 60℃ oven for low-temperature pre-drying for 5h. Then the oven temperature is increased to 120℃ at a rate of 4℃ / min and dried for another 5h. After natural cooling to room temperature, powder B is obtained. (3) Powder B is transferred to a muffle furnace and calcined at 600°C for 6 h in an air atmosphere at a rate of 5°C / min. The obtained catalyst is then pressed into tablets, crushed, and sieved to produce 40-60 mesh granular catalyst, namely PtMnSc / S-1 supported catalyst, in which the Pt loading is 0.1 wt%.

[0035] Comparative Example 1 The only difference between this comparative example and Example 1 is that cerium nitrate hexahydrate is not added, meaning that rare earth metal M2 is not added to the catalyst; otherwise, it remains the same as Example 1. The final result is a PtCu / ZSM-5 supported catalyst doped only with transition metals.

[0036] Comparative Example 2 The only difference between this comparative example and Example 1 is that copper nitrate trihydrate is not added, meaning that transition metal M1 is not added to the catalyst; otherwise, it remains the same as Example 1. The final result is a PtCe / ZSM-5 supported catalyst doped only with transition metals.

[0037] Comparative Example 3 The only difference between this comparative example and Example 1 is that copper nitrate hydrate and cerium nitrate hydrate are not added, meaning that transition metal M1 and rare earth metal M2 are not added to the catalyst. Everything else remains the same as in Example 1. The final result is a Pt / ZSM-5 supported catalyst with only Pt loading.

[0038] Comparative Example 4 The only difference between this comparative example and Example 1 is that the ZSM-5 molecular sieve support was replaced with an Al2O3 support of the same mass; otherwise, the results were identical to those in Example 1. The final product was a PtCuCe / Al2O3 supported catalyst mounted on an alumina support.

[0039] Comparative Example 5 The only difference between this comparative example and Example 2 is that lanthanum nitrate hexahydrate was replaced with the same molar amount of lutetium nitrate hexahydrate; otherwise, the results were identical to those in Example 2. The final product was a PtNiLu / MOR supported catalyst.

[0040] Comparative Example 6 The only difference between this comparative example and Example 3 is that ferric nitrate nonahydrate is replaced with the same molar amount of zinc nitrate hexahydrate; otherwise, the results are identical to those in Example 3. The final product is a PtZnY / USY supported catalyst.

[0041] Comparative Example 7 The only difference between this comparative example and Example 1 is the addition of 0.0010 g of copper nitrate trihydrate (4.14 × 10⁻⁶ g). - 6 0.0093 g cerium nitrate hexahydrate (2.14 × 10⁻⁶ mol) and 0.0093 g cerium nitrate hexahydrate (2.14 × 10⁻⁶ mol) -5 The mixed salt solution contained Cu / Ce = 0.2 (molar ratio) and (Cu+Ce) / Pt = 0.1 (molar ratio), with the remainder consistent with Example 1. The final product was a PtCuCe / ZSM-5 supported catalyst with a Pt loading of 1 wt%.

[0042] Comparative Example 8 The only difference between this comparative example and Example 3 is the addition of 0.1809 g of ferric nitrate nonahydrate (4.48 × 10⁻⁶ g). - 4 0.0245 g of yttrium nitrate hexahydrate (6.340 × 10⁻⁶ mol) and 0.0245 g of yttrium nitrate hexahydrate (6.340 × 10⁻⁶ mol). -5 The mixed salt solution contained Fe / Y = 7 (molar ratio) and (Fe+Y) / Pt = 4 (molar ratio), with the remainder consistent with Example 3. The final PtFeY / USY supported catalyst was obtained, with a Pt loading of 0.5 wt%.

[0043] Comparative Example 9 The only difference between this comparative example and Example 1 is the drying temperature and time. The low-temperature pre-drying temperature was 70°C for 2 hours, and the subsequent drying temperature was 130°C for 6 hours. The final product was a PtCuCe / ZSM-5-H supported catalyst.

[0044] Table 1 lists the supported catalysts prepared in Examples 1-5 and Comparative Examples 1-9. These catalysts were used in the catalytic combustion of ethane. During the reaction, the catalysts were packed in a fixed-bed reactor in particulate form. The reaction temperature was 150-500℃ (initial reaction temperature was 150℃, and the temperature was continuously increased during the reaction at a rate of 5℃ / min). The space velocity of the feed gas through the catalyst bed, the pressure of the reaction system, and the composition of the feed gas (including oxygen, ethane, and nitrogen) are shown in Table 2.

[0045] Table 1. Metal ratio in mixed salt solution and Pt loading in catalyst

[0046] Table 2 Comparison of Catalyst Performance

[0047] As shown in Table 2, T50 and T90 are the temperature points at which the ethane conversion rate is 50% and 90%, respectively. The results in the table show that for Pt-based supported catalysts simultaneously doped with transition metals and rare earth metals, i.e., Examples 1-5, the T50 is around 250℃, and the ethane conversion rate can reach 90% or higher at around 300℃, exhibiting high low-temperature activity. Furthermore, at 350℃, the ethane conversion rate in Examples 1-5 can all reach over 99%.

[0048] Compared to Example 1, in Comparative Example 1 without rare earth metal doping, both T50 and T90 increased significantly. This is likely due to the lack of rare earth metals, which weakens oxygen adsorption and activation, leading to a decrease in ethane conversion. In Comparative Example 2, due to the lack of transition metals affecting the electron density around Pt, both T50 and T90 increased significantly. Comparative Example 3, without any transition or rare earth metal doping, exhibited the highest T50 and T90 values. Comparative Examples 1-3 clearly demonstrate the importance of co-doping of transition and rare earth metals in the catalyst for ethane and oxygen activation, effectively improving the low-temperature performance of the catalyst and the ethane conversion efficiency. In Comparative Example 4, replacing the molecular sieve support with an alumina support resulted in a significant decrease in ethane conversion, proving that molecular sieves with high specific surface area and abundant pore structure can effectively improve the dispersion of active centers and the number of active sites.

[0049] In Comparative Example 5, the rare earth metal Lu could not provide the crucial oxygen vacancies and active oxygen species, resulting in a higher reaction temperature required to achieve the same ethane conversion rate. In Comparative Example 6, because the d orbitals of Zn were fully filled, electron transfer between Zn and Pt was difficult, thus its effect on lowering the CH bond dissociation energy barrier was small, leading to a higher reaction temperature required to achieve the same ethane conversion rate. In Comparative Example 7, the low transition metal content weakened Pt's activation ability for CH bonds, resulting in a decrease in the catalyst's low-temperature activity. In Comparative Example 8, the low rare earth metal content weakened the catalyst's activation ability for oxygen, limiting its low-temperature activity. In Comparative Example 9, the pre-drying temperature was too high and the time too short. Rapid dehydration during pre-drying, coupled with a high subsequent drying temperature, easily caused partial deformation and collapse of the support pores and facilitated the migration and aggregation of metal precursors, thereby affecting catalytic activity.

[0050] The stability of the PtMnSc / S-1 catalyst in Example 5 was evaluated with the inlet temperature set to 350 °C. The results are as follows: Figure 1 As shown, the ethane conversion rate can still be maintained above 99% after 600 h, proving that the catalyst described in this invention has high stability.

[0051] The components of the exhaust gas after the catalyst reaction in Example 1 were analyzed using an infrared analyzer, and the results are as follows: Figure 2 The characteristic absorption peaks of CH bonds and C=C double bonds were not detected. Only CO2 and H2O were detected, which proves that there are no byproducts such as ethylene and CO after the reaction, and that ethane is completely converted.

[0052] The surface morphology and elemental composition of the PtFeY / USY catalyst in Example 3 were analyzed, and the results are as follows: Figure 3 As shown, this indicates that the metal elements in the catalyst have been successfully loaded onto the molecular sieve support and are well dispersed.

[0053] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing an ethane catalytic combustion catalyst, characterized in that, Includes the following steps: (1) Dissolve chloroplatinic acid, transition metal M1 nitrate and rare earth metal M2 nitrate in water to obtain a mixed salt solution, wherein the molar ratio of M1 to M2 is 0.5-5:1; add the mixed salt solution dropwise onto a molecular sieve support for impregnation to obtain solid A; (2) After pre-drying solid A, heat it up and continue drying to obtain powder B; (3) Powder B is calcined in an aerobic environment to obtain a catalyst; the catalyst is PtM1M2 / S, wherein M1 is one or more of iron, cobalt, nickel, manganese and copper, M2 is one or more of cerium, lanthanum, scandium, yttrium and samarium, and S is a molecular sieve support.

2. The method for preparing the ethane catalytic combustion catalyst according to claim 1, characterized in that, The molar ratio of M1+M2:Pt in the mixed salt solution is 0.1-10:1; the Pt loading in the catalyst is 0.1-1 wt%.

3. The method for preparing the ethane catalytic combustion catalyst according to claim 1, characterized in that, The S is MWW molecular sieve, MFI molecular sieve, MOR molecular sieve, FAU molecular sieve or BEA molecular sieve.

4. The method for preparing the ethane catalytic combustion catalyst according to any one of claims 1-3, characterized in that, During the impregnation process, the mass ratio of the mixed salt solution to the molecular sieve carrier is 1-3:

1.

5. The method for preparing the ethane catalytic combustion catalyst according to any one of claims 1-3, characterized in that, The concentration of chloroplatinic acid in the mixed salt solution is 0.0017-0.0100 mol / L.

6. The method for preparing the ethane catalytic combustion catalyst according to claim 1, characterized in that, The pre-drying is carried out at 40-60 ℃ for 4-6 h; the continued drying is carried out at 80-120 ℃ for 4-6 h.

7. The method for preparing the ethane catalytic combustion catalyst according to claim 1 or 6, characterized in that, The roasting process involves heating the temperature to 400-600℃ at a rate of 1-5℃ / min and then maintaining this temperature for 3-6 hours.

8. The application of a catalyst prepared by the method according to any one of claims 1-7 in the catalytic combustion of ethane, characterized in that, The feed gas is brought into contact with a catalyst to carry out a catalytic combustion reaction. The feed gas includes ethane and oxygen.

9. The application according to claim 8, characterized in that, The catalytic combustion reaction is carried out at a temperature of 150-500℃ and a pressure of 0.1-0.5 MPa.

10. The application according to claim 8 or 9, characterized in that, The feed gas contains 1000-8000 ppm ethane, 2-10 vol% oxygen, and the remainder is nitrogen; the catalytic combustion reaction is carried out in a fixed-bed reactor, with the feed gas space velocity through the catalyst bed being 10000-100000 mL·g. -1 ·h -1 .

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