Ship tail gas hydrogen cyanide (HCN) purification catalyst as well as preparation method and application thereof

Abstract

The invention relates to a ship tail gas hydrogen cyanide (HCN) purification catalyst and a preparation method and application thereof. The preparation method comprises the following steps: calcining TiO2 powder to remove surface impurities and stabilize a crystal form; the preparation method comprises the following steps: respectively dissolving active components in oxalic acid / citric acid solutions, and fully stirring and mixing all component solutions; immersing the TiO2 carrier into a mixed solution containing an active component precursor, and stirring; performing rotary evaporation to remove free moisture, and drying; and roasting the dried precursor in a muffle furnace to obtain the HCN selective oxidation catalyst. According to the scheme provided by the invention, the interaction among the active components can be greatly improved, the thermal stability is high, the dispersity is high, the agglomeration of the active components can be effectively reduced, and the performance is excellent. Meanwhile, the catalyst is high in selectivity, generation of greenhouse gas N2O can be reduced, no additional treatment device needs to be added, and the use cost is reduced.

Description

Technical Field

[0001] This application relates to the technical field of ship exhaust gas purification catalysts and their preparation, and particularly relates to a Cu-V catalyst, its preparation method and application. Background Art

[0002] Hydrogen cyanide (HCN), as a highly toxic substance (e.g., the IDLH value is only 50 ppm), is classified as a toxic and harmful air pollutant (HAP) by various organizations and is managed separately. HCN is listed as a key substance under strict control, and its emission limit is extremely strict (e.g., the emission concentration in China's new sources needs to be lower than 1.0 mg / m 3 ). HCN widely exists as a pollutant in the waste gases of traditional industries such as chemical industry and electroplating, and its efficient treatment is an urgent need for atmospheric environmental protection. With the acceleration of the global industrialization process, the problem of HCN emissions has become increasingly prominent. With the implementation of the "dual carbon" policy, precise measures are taken throughout the entire chain, multi-dimensional supervision is carried out, and a tight defense line is woven. The hard constraint of carbon emission intensity drives the green transformation of industries, and the emission reduction efficiency has increased significantly, laying a rigid gate for the "dual carbon" goal. The application of biofuels and green methanol on ships has been increasing year by year. While the use of biofuel / methanol fuel reduces CO2 emissions, it generates a new pollutant, HCN.

[0003] At the same time, China is the main target for the production and consumption of new energy ships. A large amount of HCN is generated during the denitrification process of the exhaust gas of new energy ships. Due to the limited space on ships, there is currently no additional device to eliminate HCN. Therefore, the development of HCN treatment technology is particularly important.

[0004] However, traditional treatment methods (such as alkaline absorption and high-temperature incineration) have obvious defects: the absorption method requires subsequent treatment of the generated cyanide salts (such as NaCN), which is likely to cause secondary pollution; the incineration method requires a large amount of energy (>1000 °C) and may generate by-products such as NOx; the biological method is sensitive to HCN concentration and operating conditions and has insufficient stability. Among them, the catalytic oxidation method can oxidize and decompose HCN and is considered an effective method. However, most of the current catalysts are only applicable to the low-temperature range (e.g., below 200 °C) when catalytically oxidizing HCN. When facing high temperatures or other complex working conditions, when using the existing catalysts to catalytically oxidize HCN at high temperatures (e.g., 300 - 500 °C), a large amount of by-products (nitrogen oxides NOx, N2O) will be generated, which is likely to cause secondary pollution. In order to reduce the emission of NOx, ships have to additionally install devices for treating NOx in the exhaust gas. At the same time, the main components of the existing catalysts are precious metals, molecular sieves, and activated carbon, and the cost is high, which greatly increases the operating cost of ships.

[0005] Therefore, there is an urgent need for a catalytic material and technology that is inexpensive, has high thermal stability, excellent catalytic performance, high selectivity, can effectively reduce the generation of nitrogen oxides, is environmentally friendly, does not require additional devices for treating NOx, reduces production and operation costs, and has a simple preparation method and convenient operation. Summary of the Invention

[0006] To overcome the problems existing in the related art, the present application provides a Cu-V-W catalyst, its preparation method and application. The Cu-V catalyst, its preparation method and application can greatly increase the interaction between active components, have high thermal stability, high dispersion, effectively reduce the aggregation of active components, and have excellent performance. At the same time, the catalyst has high selectivity, can reduce the generation of nitrogen oxides, does not require additional devices for treating NOx, reduces production and operation costs, and has a simple preparation method and convenient operation.

[0007] The object of the present invention is achieved by at least one of the following technical solutions.

[0008] One object of the present application is to provide a preparation method of the catalyst for purifying hydrogen cyanide (HCN) in ship exhaust gas, which is characterized by including the following steps:

[0009] (1) Pretreatment: Calcining TiO2 to remove surface impurities and stabilize the crystal form, dissolving the active components and the cosolvent in a solvent, and stirring and mixing each component to obtain an active component mixed solution; wherein, the calcination temperature is 300-450°C;

[0010] (2) Impregnation: Immersing the TiO2 carrier in the active component mixed solution, with a solid-liquid ratio of 1 g: 1.5-4.5 mL, rotary evaporation and drying;

[0011] (3) Calcination and shaping: Placing the dried precursor in a muffle furnace for calcination, and obtaining the powder catalyst through coating and shaping to obtain the HCN selective oxidation catalyst.

[0012] Preferably, the active component mixed solution includes a transition metal source, a V source, and a W source, wherein the transition metal source includes Cu. The transition metal source is selected from one or more of copper nitrate, copper acetate, and copper oxalate; the V source is selected from ammonium metavanadate; the W source is selected from ammonium metatungstate.

[0013] Preferably, the cosolvent includes one or both of oxalic acid and citric acid. The concentration of the cosolvent in the solution is 50-200 mg / L.

[0014] Preferably, the active component additive added during impregnation includes polyacrylic acid; the impregnation time is 6-12 hours; the drying temperature is 80-120°C, and the drying time is 6-10 hours; the calcination temperature is 450-550°C, and the calcination time is 4-6 hours.

[0015] In a preferred technical solution of the present application, the conditions of the transition metal active component solution are as follows: the Cu salt solution is prepared to account for 0.5-5 w% of the total catalyst calculated by the mass of copper oxide; the conditions of the V and W solutions are as follows: the V salt solution is prepared to account for 0.5-2 w% of the total catalyst calculated by the mass of vanadium pentoxide, and the W salt solution is prepared to account for 4-8 w% of the total catalyst calculated by the mass of tungsten trioxide.

[0016] In a preferred technical solution of the present application, the specific steps of the impregnation include: stirring and mixing the transition metal solution with the V and W solutions, adding polyacrylic acid, stirring at 60-80 °C for 6-12 hours, rotary evaporating to remove free water, and drying at 80-120 °C for 12 hours. [[ID=!6]]

[0017] In a preferred technical solution of the present application, the calcination temperature for the calcination molding is 450-550 °C, and the calcination time is 4-6 h.

[0018] In a preferred technical solution of the present application, the Cu source includes any one of copper nitrate, copper acetate, and copper oxalate.

[0019] Another object of the present application is to provide a catalyst for purifying hydrogen cyanide (HCN) in ship exhaust gas. The catalyst contains Cu, V, and W elements, including 1-4 wt% CuO, 0.5-2 wt% V2O5, and 4-8 wt% WO3. In the catalyst, Cu plays an oxidation role and V plays a reduction role; the ratio between the two does not exceed 1:4, achieving high temperature and high selectivity; the catalyst is applied to catalytically oxidize HCN waste gas, specifically for catalytic oxidation when catalyzing HCN in the ship's tail gas.

[0020] The catalytic oxidation temperature is 200-500 °C.

[0021] The technical solution provided by the present application may include the following beneficial effects:

[0022] (1) The present application uses an impregnation method to load multiple active components on the TiO2 support, which can make the loading of multiple active components uniform, effectively improve the dispersion degree of the active components, and there is a synergistic effect between the Cu / V dual active components provided by the present application, which can effectively improve the selectivity of the catalyst.

[0023] (2) For the preparation method provided by the present application, by adding citric acid to the transition metal solution, adding oxalic acid additives to the V and W solutions, and adding polyacrylic acid during the impregnation process, it can promote the formation of a load layer with a relatively high dispersion degree of the active components on the surface of the support, that is, the citric acid and polyacrylic acid additives added in the present application can effectively reduce the agglomeration of the active components and improve the stability of the catalyst.

[0024] (3) The preparation method provided by this application is simple, without the use of precious metals, with a small amount of transition metals, low cost, and simple operation.

[0025] (4) The Cu-V-W catalyst provided by this application has high reaction activity when applied to the catalytic oxidation of ship exhaust gas containing HCN, has good catalytic oxidation effect on HCN, good purification effect, and the by-products generated at high temperature are much lower than those of other catalysts, with high stability, high performance, and high selectivity, and excellent comprehensive performance.

[0026] In summary, the Cu-V-W catalyst provided by this application can greatly increase the dispersion degree of active components, has uniform loading, high thermal stability, effectively reduces the agglomeration of active components, and has excellent catalytic performance. At the same time, this catalyst has high selectivity, can effectively reduce the generation of nitrogen oxides, is environmentally friendly, does not require additional devices for treating NOx, reduces the operating cost, and has a simple preparation method and simple operation. Description of the Drawings

[0027] Figure 1 is a process schematic diagram of the preparation method of the ship HCN tail gas purification catalyst shown in the embodiments of this application;

[0028] Figure 2 is the X-ray diffraction test pattern (XRD) of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 of this application;

[0029] Figure 3 is the conversion rate diagram of HCN when the ship HCN catalyst prepared in the embodiments and comparative examples of this application catalyzes the oxidation of HCN;

[0030] Figure 4 is the generation amount diagram of N2O when the ship HCN catalyst prepared in the embodiments and comparative examples of this application catalyzes the oxidation of HCN;

[0031] Figure 5 is the generation amount diagram of NO when the ship HCN catalyst prepared in the embodiments and comparative examples of this application catalyzes the oxidation of HCN;

[0032] Figure 6 is the generation amount diagram of CO when the ship HCN catalyst prepared in the embodiments and comparative examples of this application catalyzes the oxidation of HCN;

[0033] Figure 7 is the high-temperature stability performance diagram of the ship HCN catalyst shown in the embodiments of this application. Detailed Embodiments

[0034] The following is a further detailed description of the above content of the present invention through specific embodiments in the form of examples. However, this should not be construed as limiting the scope of the above subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0035] Currently, the treatment technologies for HCN mainly focus on physical adsorption and chemical neutralization. Physical adsorption requires regular replacement of the adsorption material. Alkaline absorption (such as NaOH solution) generates NaCN, which is then oxidized and decomposed into non-toxic substances by hypochlorite. These two methods are inconvenient for operation in the narrow space of ships. At the same time, when the existing catalysts for catalytic oxidation of VOCs are applied in the catalytic process of HCN, a large amount of by-products such as N2O and NH3 are generated, which is likely to cause secondary pollution. In order to reduce the emission of NOx, shipowners have to additionally install devices for treating NOx in the exhaust gas treatment, which greatly increases the production cost of enterprises.

[0036] In view of the above problems, the embodiments of the present application provide a ship HCN catalyst, its preparation method and application, which can greatly increase the dispersion degree of active components, have uniform loading, high thermal stability, effectively reduce the agglomeration of active components, and have excellent catalytic performance. At the same time, the catalyst has high selectivity, can effectively reduce the generation of nitrogen oxides, is environmentally friendly, shipowners do not need to install devices for treating NOx, which reduces the operation cost of shipowners, and the preparation method is simple and the operation is convenient.

[0037] The following details the technical solutions of the embodiments of the present application with reference to the accompanying drawings.

[0038] Please refer to Figure 1 , Figure 1 which is a schematic flowchart of the preparation method of the Cu-V catalyst shown in the embodiments of the present application.

[0039] The preparation method of the Cu-V catalyst provided by the present application specifically includes the following steps:

[0040] S1. Pretreatment: Calcinate TiO2 to remove surface impurities and stabilize the crystal form. The active components are dissolved in oxalic acid / citric acid, and each component is stirred and mixed to obtain an active component mixed solution, where the calcination temperature is 300-450°C;

[0041] It should be noted that for the active components, in the following examples and comparative examples, the conditions of the transition metal active component solution are as follows: the Cu salt solution is configured to account for 0.5-5 w% of the total catalyst calculated by the mass of copper oxide; the conditions of the V and W solutions are: the V salt solution is configured to account for 0.5-2 w% of the total catalyst calculated by the mass of vanadium pentoxide, and the W salt solution is configured to account for 4-8 w% of the total catalyst calculated by the mass of tungsten trioxide.

[0042] S2. Impregnation: Immerse the TiO2 support in the mixed solution of active components with a solid-liquid ratio of 1:3, then perform rotary evaporation and drying.

[0043] S3. Calcination: Place the dried precursor in a muffle furnace for calcination to obtain the HCN selective oxidation catalyst.

[0044] This application also provides an application of the above Cu-V catalyst in the catalytic oxidation of HCN-containing waste gas. When the Cu-V catalyst is applied to catalytically oxidize HCN-containing waste gas in an enameling furnace, the catalytic oxidation temperature is 200 - 400 °C.

[0045] The performance of the stainless steel support catalyst of this application is described in detail below through specific examples and comparative examples in combination with the drawings.

[0046] Example 1

[0047] The preparation method of the ship HCN catalyst in Example 1 of this application specifically includes the following steps:

[0048] S1.1. Weigh 7.2 g of 30 - 60 nm anatase TiO2, place it in a crucible and calcine it in a tube furnace at 400 °C for 4 hours to obtain the surface-purified TiO2 support.

[0049] S1.2. Weigh 0.528 g of ammonium metatungstate, 0.103 g of ammonium metavanadate, 0.729 g of copper nitrate, and 0.1 g of oxalic acid, dissolve them in 500 ml of deionized water, heat it to 65 °C using a heating magnetic stirrer with a magnetic stirring speed of 350 r / min to prepare the mixed active component solution A, denoted as the CuVW mixed solution.

[0050] S2. Immerse the TiO2 support prepared in S1 into the mixed active component solution A prepared in S1.2, add 10 drops of polyacrylic acid, with a solid-liquid ratio of 1:3 g / mL, perform rotary evaporation for 6 hours and dry at 100 °C for 8 hours to obtain the intermediate product B, denoted as Cu-VWT.

[0051] S3. Place the intermediate product B in a muffle furnace at 500 °C for calcination for 6 h to obtain the ship HCN catalyst, denoted as xCuO-VWT.

[0052] Example 2

[0053] The preparation method of the ship HCN catalyst in Example 2 of this application specifically includes the following steps:

[0054] S1.1. Weigh 7.2 g of 30 - 60 nm anatase TiO2, place it in a crucible and calcine it in a tube furnace at 400 °C for 4 hours to obtain the surface-purified TiO2 support.

[0055] S1.2: Weigh 0.528 g of ammonium metatungstate, 0.103 g of ammonium metavanadate, 0.243 g of copper nitrate, and 0.1 g of oxalic acid. Dissolve them in 500 ml of deionized water. Heat the solution to 65 °C using a heating magnetic stirrer with a magnetic stirring speed of 350 r / min to obtain the active component mixed solution A, denoted as the CuVW mixed solution.

[0056] S2: Immerse the TiO2 support prepared in S1 into the active component mixed solution A prepared in S1.2. Add 10 drops of polyacrylic acid. The solid-liquid ratio is 1:3 g / mL. Rotate and evaporate for 6 hours and dry at 100 °C for 8 hours to obtain the intermediate product B, denoted as Cu-VWT.

[0057] S3: Place the intermediate product B in a muffle furnace at 500 °C and calcine for 6 h to obtain the ship HCN catalyst, denoted as xCuO-VWT.

[0058] Example 3

[0059] The preparation method of the ship HCN catalyst in Example 3 of this application specifically includes the following steps:

[0060] S1.1: Weigh 7.2 g of 30-60 nm anatase TiO2 and place it in a crucible. Calcinate it in a tubular furnace at 400 °C for 4 hours to obtain the surface-purified TiO2 support.

[0061] S1.2: Weigh 0.528 g of ammonium metatungstate, 0.103 g of ammonium metavanadate, 0.243 g of copper nitrate, 0.05 g of oxalic acid, and 0.05 g of citric acid. Dissolve them in 500 ml of deionized water. Heat the solution to 65 °C using a heating magnetic stirrer with a magnetic stirring speed of 350 r / min to obtain the active component mixed solution A, denoted as the CuVW mixed solution.

[0062] S2: Immerse the TiO2 support prepared in S1 into the active component mixed solution A prepared in S1.2. Add 10 drops of polyacrylic acid. The solid-liquid ratio is 1:3 g / mL. Rotate and evaporate for 6 hours and dry at 100 °C for 8 hours to obtain the intermediate product B, denoted as Cu-VWT.

[0063] S3: Place the intermediate product B in a muffle furnace at 500 °C and calcine for 6 h to obtain the ship HCN catalyst, denoted as xCuO-VWT.

[0064] Comparative Example 1

[0065] S1.1: Weigh 7.2 g of 30-60 nm anatase TiO2 and place it in a crucible. Calcinate it in a tubular furnace at 400 °C for 4 hours to obtain the surface-purified TiO2 support.

[0066] S1.2. Weigh 0.528 g of ammonium metatungstate, 0.103 g of ammonium metavanadate, and 0.1 g of oxalic acid, dissolve them in 500 ml of deionized water, heat to 65 °C using a heating magnetic stirrer with a magnetic stirring speed of 350 r / min to obtain the active component mixed solution A, denoted as the VW mixed solution.

[0067] S2. Immerse the TiO2 support prepared in S1 into the active component mixed solution A prepared in S1.2, add 10 drops of polyacrylic acid, with a solid-liquid ratio of 1:3 g / mL, perform rotary evaporation for 6 hours and dry at 100 °C for 8 hours to obtain the intermediate product B, denoted as VWT-pre.

[0068] S3. Place the intermediate product B in a muffle furnace at 500 °C and calcine for 6 h to obtain the ship HCN catalyst, denoted as VWT.

[0069] Comparative Example 2

[0070] S1.1. Weigh 7.2 g of 30 - 60 nm anatase TiO2, place it in a crucible and calcine in a tube furnace at 400 °C for 4 hours to obtain the surface-purified TiO2 support.

[0071] S1.2. Weigh 4.306 g of cerium nitrate, 0.243 g of copper nitrate, and 0.1 g of oxalic acid, dissolve them in 500 ml of deionized water, heat to 65 °C using a heating magnetic stirrer with a magnetic stirring speed of 350 r / min to obtain the active component mixed solution A, denoted as the CuCe mixed solution.

[0072] S2. Immerse the TiO2 support prepared in S1 into the active component mixed solution A prepared in S1.2, add 10 drops of polyacrylic acid, with a solid-liquid ratio of 1:3 g / mL, perform rotary evaporation for 6 hours and dry at 100 °C for 8 hours to obtain the intermediate product B, denoted as Cu-Ce-T-pre.

[0073] S3. Place the intermediate product B in a muffle furnace at 500 °C and calcine for 6 h to obtain the ship HCN catalyst, denoted as xCuO-CeO-T.

[0074] Comparative Example 3

[0075] S1.1. Weigh 7.2 g of 30 - 60 nm anatase TiO2, place it in a crucible and calcine in a tube furnace at 400 °C for 4 hours to obtain the surface-purified TiO2 support.

[0076] S1.2. Weigh 0.528 g of ammonium metatungstate, 0.103 g of ammonium metavanadate, 1.243 g of iron nitrate, and 0.05 g of citric acid, dissolve them in 500 ml of deionized water, heat to 65 °C using a heating magnetic stirrer with a magnetic stirring speed of 350 r / min to obtain the active component mixed solution A, denoted as the FeVW mixed solution.

[0077] S2. Immerse the TiO2 support prepared in S1 into the active component mixed solution A prepared in S1.2, add 10 drops of polyacrylic acid, with a solid-liquid ratio of 1:3 g / mL, perform rotary evaporation for 6 hours and dry at 100 °C for 8 hours to obtain the intermediate product B, denoted as Cu-VWT.

[0078] S3. Place the intermediate product B in a muffle furnace at 500 °C and calcine for 6 h to obtain the ship HCN catalyst, denoted as xCuO-VWT.

[0079] Performance test experiment

[0080] 1. X-ray diffraction (XRD) characterization test

[0081] Perform XRD characterization tests on the stainless steel support catalysts prepared in Examples 1-3 and Comparative Examples 1-3. The results are as Figure 2 shown. It can be seen from the XRD in the figure that the active components are all uniformly loaded on TiO2, which indicates that by using the preparation method provided in this application, the active components can be effectively and uniformly loaded on the support TiO2.

[0082] 2. Active test - HCN purification performance test

[0083] Prepare the catalyst into particles with a mesh size of 40-60. Weigh an appropriate amount of the catalyst and place it in a fixed-bed quartz tube reactor. Test the HCN purification performance (i.e., the conversion rate of HCN) and the by-product generation amount of the sample at 150-400 °C under a simulated atmosphere (HCN: 100 ppm, O2: 15 vol%, the rest N2), where the total gas flow rate is 200 mL / min (mass space velocity GHSV = 12000 h -1 -1), and at the same time, conduct a stability test on the ship HCN catalyst at 400 °C for 48 h. The results are as Figures 3 - 6 shown.

[0084] As Figure 3 shown, when using the ship HCN catalysts prepared in Examples 1-3 and Comparative Example 2 to catalytically oxidize HCN (i.e., purify HCN), the conversion rate of HCN can be maintained between 95-100%, especially in the temperature range of 250-300 °C, the conversion rate of HCN can reach 99%. While using the catalysts in Comparative Example 1 and Comparative Example 3, the conversion rate of HCN is lower than 10%, and is far lower than the ship HCN catalyst provided in this application.

[0085] As Figure 4As shown, when the stainless-steel supported catalyst prepared in Examples 1 - 3 is used to catalytically oxidize HCN, the content of by-product N2O generated at 350°C is much lower than that of the by-product N2O generated by catalytically oxidizing with the catalysts in Comparative Examples 2 - 3 at high temperature. This shows that when the ship HCN catalyst provided in this application catalytically oxidizes HCN at high temperature, it can effectively reduce the generation of by-product N2O, greatly reduce secondary pollution, and reduce the operation cost of shipowners.

[0086] As Figure 5 shown, when the stainless-steel supported catalyst prepared in Examples 1 - 3 is used to catalytically oxidize HCN, the content of by-product NO generated at 350°C is much lower than that of the by-product NO generated by catalytically oxidizing with the catalysts in Comparative Examples 2 - 3 at high temperature. This shows that when the ship HCN catalyst provided in this application catalytically oxidizes HCN at high temperature, it can effectively reduce the generation of by-product NO, greatly reduce secondary pollution, and reduce the operation cost of shipowners.

[0087] As Figure 6 shown, when the ship HCN catalyst prepared in Examples 1 - 3 is used to catalytically oxidize HCN, the content of by-product CO generated at high temperature (about 10 ppm) is much lower than that of the by-product CO generated by catalytically oxidizing with the catalysts in Comparative Examples 1 - 3 at high temperature (greater than 50 ppm). This shows that when the stainless-steel supported catalyst provided in this application catalytically oxidizes HCN at high temperature, it can greatly reduce the generation of by-product CO and is environmentally friendly.

[0088] In summary, according to Figures 3 - 6 it can be seen that the ship HCN catalyst provided in this application has high reaction activity, good catalytic oxidation effect of HCN, and the by-products generated at high temperature are much lower than those of the catalysts in the comparative examples. This shows that the catalyst provided in this application can reduce the oxidation activity of nitrogen-containing organic waste gas oxidized to nitrogen oxides at high temperature. At the same time, the Cu catalytic performance (high-temperature selectivity performance) of this application is much better than that of the Fe active component, indicating that there is a synergistic effect between the Cu-V double active components provided in this application, which can effectively enhance the electron transfer between Cu and V, and there is also an interaction between the metal oxides formed after calcination, effectively improving the high efficiency and high selectivity of the catalyst in catalytically oxidizing organic waste gas. This effect cannot be achieved by any double active components.

[0089] 5. Stability performance test

[0090] The Cu-V catalyst prepared in Example 2 was used to catalytically oxidize HCN at 350°C for 48 hours, and the results are as Figure 7 shown.

[0091] From Figure 7As can be seen, within 24 hours, the conversion rate of the HCN basically remains between 98% and 100%, indicating that the Cu-V catalyst prepared by the preparation method of the present application can continuously maintain stable reaction activity at a high temperature of 350°C, and the selectivity has no obvious change, and the catalytic oxidation effect on HCN is good, indicating that the ship HCN catalyst provided by the present application still has good stability and selectivity under high temperature conditions.

[0092] The embodiments of the present application have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles of the embodiments, the practical application, or the improvement of the technology in the market, or to enable other ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A purification catalyst for hydrogen cyanide (HCN) in ship exhaust gas, characterized in that, The catalyst contains Cu, V and W elements, including 1-4 wt% CuO, 0.5-2 wt% V2O5, 4-8 wt% WO3. In the catalyst, Cu plays an oxidation role and V plays a reduction role; The ratio of the two does not exceed 1:4, achieving high temperature and high selectivity; the catalyst is applied to catalytic oxidation of HCN waste gas.

2. The purification catalyst for hydrogen cyanide (HCN) in ship exhaust gas according to claim 1, characterized in that, The catalytic oxidation temperature is 200-500 °C.

3. The preparation method of the ship exhaust hydrogen cyanide (HCN) purification catalyst according to claim 1 or 2, characterized in that, It includes the following steps: (1) Pretreatment: Calcining TiO2 to remove surface impurities and stabilize the crystal form, dissolving the active components and co-solvents in a solvent, and stirring and mixing each component to obtain an active component mixed solution; among them, the calcination temperature is 300-450 °C; (2) Impregnation: Immersing the TiO2 support in the active component mixed solution, with a solid-liquid ratio of 1 g: 1.5-4.5 mL, rotary evaporation and drying; (3) Roasting and forming: Placing the dried precursor in a muffle furnace for roasting, and the obtained powder catalyst is coated and formed to obtain a HCN selective oxidation catalyst.

4. The preparation method according to claim 3, characterized in that, In step (1), the active components include a transition metal source, a V source and a W source, and the transition metal source is Cu.

5. The preparation method according to claim 4, characterized in that, The transition metal source is selected from one or more of copper nitrate, copper acetate and copper oxalate; the V source is selected from ammonium metavanadate; the W source is selected from ammonium metatungstate.

6. The preparation method according to claim 3, characterized in that, In step (1), the co-solvent includes one or more of oxalic acid and citric acid.

7. The preparation method according to claim 3, characterized in that, In step (2), an active component additive is added during the impregnation process, and the active component additive is polyacrylic acid; the impregnation time is 6-12 hours; the drying temperature is 80-120 °C, and the drying time is 6-10 hours.

8. The preparation method according to claim 3, characterized in that, In step (3), the roasting temperature is 450-550 °C, and the roasting time is 4-6 hours.

9. The preparation method according to claim 5, characterized in that The concentration of the co-solvent in the solution is 50-200 mg / L.

10. The preparation method according to claim 4, wherein, The conditions of the active component solution of the transition metal source are: The Cu salt solution is configured to account for 0.5-5 wt% of the total catalyst calculated by the mass of copper oxide; The conditions of the solutions of the V source and the W source are: The V salt solution is configured to account for 0.5-2 wt% of the total catalyst calculated by the mass of vanadium pentoxide, and the W salt solution is configured to account for 4-8 wt% of the total catalyst calculated by the mass of tungsten trioxide.

Images