Catalyst for dehydrogenation in chlorine-containing environments, preparation method and application thereof

Abstract

The present application discloses a catalyst for dehydrogenation in a chlorine-containing environment, its preparation method, and application, and belongs to the field of catalyst reaction technology. The catalyst includes a carrier and an active ingredient: the carrier includes ZrO2 and MgFeO4; the active ingredient includes an auxiliary agent and a precious metal component, the auxiliary agent includes V2O5-WO3 composite oxide and CeO2-MnO2 composite oxide, and the precious metal component includes at least three of rhodium, ruthenium, platinum, palladium, and gold. The precious metal component is confined to the mesopores of the carrier, while the auxiliary agent with dechlorination and catalytic oxidation functions is evenly distributed on the surface of the carrier, realizing a two-step catalytic strategy of first dechlorination and then oxidation of chlorine-containing waste gas, effectively avoiding the occurrence of catalyst poisoning and forming an excellent catalytic effect. In addition, its properties are stable and it still maintains excellent catalytic function after long-term use, making it more practical and economical.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst reaction, and particularly relates to a catalyst for dehydrogenation in a chlorine-containing environment, a preparation method and an application thereof. Background Art

[0002] Epichlorohydrin is a widely used basic organic chemical raw material and a key raw material for the synthesis of products such as epoxy resins and epichlorohydrin rubber, occupying a vital position in the national economy. The main industrial production methods for epichlorohydrin are the chlorohydrin process and the allyl alcohol process. These processes generate a large amount of waste gas, including acrolein, epichlorohydrin, hydrogen chloride, methyl chloride, ethylene oxide, chlorobenzene, and other impurities. These waste gases are irritating to the respiratory tract and mucous membranes, deplete ozone, and pollute the environment, thus failing to meet environmental protection requirements and requiring waste gas purification.

[0003] Existing methods for purifying waste gas containing organic matter primarily include UV photolysis, activated carbon adsorption, and catalytic oxidation. UV photolysis uses high-energy ultraviolet light to decompose organic matter into carbon dioxide and water, but the equipment is expensive and the operating costs are extremely high, making it unsuitable for large-scale industrial applications.

[0004] Activated carbon has limited adsorption capacity. In practice, even with a large amount of activated carbon, it is often difficult to effectively remove waste gas, which makes the cost of use high. Moreover, as a broad-spectrum adsorbent, activated carbon has limited adsorption capacity for specific compounds. There is also a risk of secondary pollution.

[0005] The catalytic oxidation method is a mature and widely used technology. It can achieve complete purification of VOCs gas at a relatively low temperature without the problem of secondary pollution. It is an effective purification method with high purification efficiency and a wide range of applications. However, the catalytic oxidation effect of existing catalysts on chlorine-containing organic waste gas is average. The reason is that the chlorine element undergoes a strong adsorption reaction with the active metal on the catalyst surface during the catalytic process to form stable metal chlorides or oxychlorides. These compounds cover the active sites of the catalyst, making the catalyst surface unable to effectively adsorb and activate VOCs gas. That is, the precious metal catalyst loses its redox ability due to the strong adsorption of chlorine in a chlorine-containing environment, and it is difficult to restore its activity through conventional regeneration methods, which is commonly known as "catalyst poisoning." Catalyst poisoning makes it difficult to decompose and treat chlorine-containing organic waste gas through catalytic oxidation, and the cost of other methods is too high, which has become a difficult problem for environmental tail gas treatment. Summary of the Invention

[0006] In view of this, the purpose of the embodiments of the present application is to provide a catalyst for dehydrogenation in a chlorine-containing environment, its preparation method and application, so as to solve the problem in the prior art that when catalytically oxidizing chlorine-containing organic waste gas, the catalyst is easily poisoned, loses or partially loses its catalytic ability, resulting in poor catalytic effect. The catalyst provided in the embodiments of the present application has a strong regeneration ability, can be regenerated through simple operations, and can be used multiple times after regeneration without damaging the catalytic effect of the catalyst, so it is more practical and more economical. The preparation method of the catalyst provided in the embodiments of the present application is simple and environmentally friendly, easy to operate, and suitable for industrial applications.

[0007] The embodiment of the present application is implemented as follows:

[0008] A catalyst for dehydrogenation in a chlorine-containing environment, comprising a carrier and an active component:

[0009] The carrier includes ZrO2 and MgFeO4;

[0010] The active ingredients include auxiliary agents and precious metal components. The auxiliary agents include V2O5-WO3 composite oxides and CeO2-MnO2 composite oxides. The precious metal components include at least three of rhodium, ruthenium, platinum, palladium and gold.

[0011] Preferably, the mass percentage of the active ingredient in the catalyst is 10-50%.

[0012] Preferably, the molar ratio of Zr, Mg and Fe in the carrier is 1:0.5:1.

[0013] Preferably, the molar ratio of vanadium to tungsten in the active ingredient is (2.5-3.5):1, the molar ratio of cerium to manganese is 1:(1.5-2.5), and the molar ratio of tungsten to cerium is 1:1.

[0014] The present application also provides a method for preparing the above-mentioned catalyst for dehydrogenation in a chlorine-containing environment, comprising the following steps:

[0015] S1. Prepare a carrier with a large number of mesopores on the surface;

[0016] S2. The carrier is immersed in a precious metal solution, vacuum evaporated, dried, and calcined to distribute the precious metal ions in the mesopores of the carrier to obtain a semi-finished product;

[0017] S3. Immerse the semi-finished product in a mixed solution of vanadium and tungsten, dry it, and then calcine it; then immerse it in a mixed solution of manganese and cerium, dry it, and then calcine it to obtain a finished catalyst.

[0018] Preferably, step S1 includes the following steps:

[0019] S11. The zirconium salt solution, magnesium nitrate solution, ferric nitrate solution and cetyltrimethylammonium bromide were dissolved in ethanol and stirred;

[0020] S12. Ammonia was added to adjust the pH to 8-10, and then the temperature was raised to 40-60 ° C and ethylene glycol was added. The hydrolysis reaction was carried out for 2-4 hours to obtain a wet gel;

[0021] S13. The wet gel was aged at room temperature for 24-48 h, then washed and vacuum dried at 80-100 ° C for 12-24 h;

[0022] S14. Calcinate at 300-400℃ for 2-4h, then raise the temperature to 550-700℃ and calcine for 4-6h.

[0023] Preferably, the precious metal solution in step S2 includes at least three of rhodium solution, ruthenium solution, platinum solution, palladium solution, and gold solution, is vacuum evaporated for 4 hours, vacuum dried for more than 24 hours, and calcined at 600° C. in a nitrogen atmosphere for 5 hours.

[0024] Preferably, in step S3, the immersion is at room temperature; the drying temperature is 80-100° C. and the time is more than 8 hours; and the calcination temperature in a nitrogen atmosphere is 600° C. and the time is 5 hours.

[0025] The present application also provides the use of the above catalyst for dehydrogenation in a chlorine-containing environment or the catalyst prepared by the above method in removing chlorine-containing organic matter and organic matter.

[0026] Preferably, the chlorine-containing organic matter includes at least one of epichlorohydrin and methyl chloride, and the organic matter includes at least one of acrolein and ethylene oxide.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] 1. The catalyst for dehydrogenation in a chlorine-containing environment provided by the present application adopts a carrier material with a large number of mesopores on the surface; the large number of mesopores on the surface increases the specific surface area in contact with organic gases and chlorine-containing organic gases, providing more active sites; and the original carrier material formula, ZrO2, can resist the corrosion of chloride ions due to its high thermal stability and acid resistance, and helps the carrier maintain a stable structure at high temperatures. The spinel structure of MgFeO4 provides alkaline sites that can neutralize the acidic byproduct HCl caused by chloride ions. It reduces the poisoning of precious metal components by chloride ions, etc., and improves the catalytic oxidation effect of hydrocarbon-containing gases in chlorine-containing environments; and the carrier structure is stable and can be used for a long time without collapsing or collapse, and continuously maintains an excellent catalytic effect.

[0029] 2. The present application provides a catalyst for dehydrogenation in a chlorine-containing environment. The active ingredient in the catalyst is uniformly distributed on the surface of the carrier by a room-temperature impregnation method, while the precious metal component is distributed within the mesopores of the carrier. This design can effectively decompose and remove chloride ions, reduce the interference of chloride ions on the precious metal, and achieve sustained and effective catalytic performance. The principle is that the WO3 in the additive can preferentially adsorb chlorine-containing organic matter, reducing the entry of chloride ions into the mesopores and contact with the precious metal component, and reducing the adsorption of chlorine-containing organic matter by other active ingredients; the lattice oxygen of V2O5 can accelerate the breaking of C-Cl bonds, and the multivalent vanadium-tungsten oxide can promote redox reactions during the catalytic process, and the large amount of chloride ions generated are reduced to chlorine gas. During the redox process, cerium, as an oxygen storage material, provides active oxygen and improves the oxygen migration capacity, while manganese ions promote the formation of oxygen vacancies, enhance the oxidation kinetics of chloride ions, promote the process of chloride ions being reduced to chlorine gas, and reduce the occurrence of chlorine poisoning of the precious metal component. The high electron mobility of manganese ions accelerates the deep oxidation process of intermediate products, effectively reducing the formation of dioxins. The combined use of the main and auxiliary phases of the additives and the synergistic effect between the elements allow the chloride ions to be essentially removed and decomposed, significantly reducing the occurrence of chlorine poisoning and effectively enhancing the oxidation effect on organic gases. DETAILED DESCRIPTION

[0030] To make the objectives, technical solutions, and advantages of this application more clearly understood, this application is further described in detail below in conjunction with examples. The illustrative embodiments and descriptions of this application are intended only to explain this application and are not intended to limit this application. Any product identical or similar to the present application that is derived by anyone under the guidance of this application or by combining the features of this application with other prior arts shall fall within the scope of protection of this application.

[0031] Specific experimental steps or conditions not specified in the examples can be carried out according to the conventional experimental steps or conditions described in the prior art. The reagents and other instruments used, whose manufacturers are not specified, are all commercially available conventional reagents.

[0032] The present embodiment provides a catalyst for dehydrogenation in a chlorine-containing environment, comprising a carrier and an active ingredient, wherein the active ingredient comprises a promoter and a precious metal component. The active ingredient preferably accounts for 10-50% by weight of the catalyst, more preferably 15-25% by weight. The mass ratio of the promoter to the precious metal component in the active ingredient is preferably (2-4):1, more preferably 2.5:1.

[0033] The carrier is a porous metal composite material, the main component of which is ZrO2-MgFeO4 composite oxide; in ZrO2-MgFeO4, the molar ratio of Zr, Mg and Fe is preferably 1:0.5:1.

[0034] The carrier has a large number of mesopores, giving it a large specific surface area. Due to its structural design, the precious metal components that catalyze the oxidation of hydrocarbon-containing exhaust gases are confined to the pores of the metal composite material, while the additives that perform both chlorine removal and catalytic oxidation are evenly distributed on the carrier surface and within the mesopores. This achieves a two-step catalytic strategy for chlorine-containing exhaust gases: first dechlorination, then oxidation. This effectively avoids catalyst poisoning and achieves excellent catalytic results.

[0035] The additive comprises a primary phase and a secondary phase. The primary phase is specifically a vanadium-tungsten bimetallic oxide, namely, V2O5-WO3 nanoclusters, wherein the molar ratio of vanadium to tungsten is preferably (2.5-3.5):1. The secondary phase is specifically a cerium-manganese composite oxide, namely, CeO2-MnO2 nanoclusters, wherein the molar ratio of cerium to manganese is preferably 1:(1.5-2.5). Furthermore, the molar ratio of tungsten to cerium is preferably 1:1.

[0036] Precious metal components include any three or more of rhodium, ruthenium, platinum, palladium, and gold. As active elements, these precious metals effectively catalyze the oxidation of hydrocarbon-containing organic gases into carbon dioxide and water, purifying exhaust gases. Precious metals have a long history as active catalyst components, and the technologies for their use, regeneration, and recovery are mature and readily available.

[0037] Because the bond energy of the C-Cl bond is lower than that of the C-H bond, it breaks before the C-H bond during the catalytic oxidation process, producing free Cl ions. When chlorine-containing gas contacts the catalyst, it first comes into contact with the external support, ZrO2-MgFeO4, and the additives distributed on the support surface. ZrO2, with its high thermal stability and acid resistance, resists corrosion from chloride ions and helps the support maintain a stable structure at high temperatures. The spinel structure of MgFeO4 provides alkaline sites that can neutralize the acidic byproduct HCl triggered by chloride ions. This reduces the poisoning of precious metal components by chloride ions and improves the catalytic oxidation of hydrocarbon gases in a chlorine-containing environment.

[0038] When chlorine-containing waste gas comes into contact with the additive, WO3 preferentially adsorbs chlorinated organic matter based on Lewis acid-base theory, reducing the entry of chloride ions into the mesopores and their contact with the precious metal components, thereby reducing the adsorption of chlorinated organic matter by other active components. The lattice oxygen of V2O5 accelerates the breakage of C-Cl bonds, and the multivalent vanadium-tungsten oxide promotes redox reactions during the catalytic process, reducing the generated chloride ions to chlorine gas. During the redox process, cerium, as an oxygen storage material, provides active oxygen and enhances oxygen mobility, while manganese ions promote the formation of oxygen vacancies, enhancing the oxidation kinetics of chloride ions and facilitating their reduction to chlorine gas, thereby reducing chlorine poisoning of the precious metal components. Furthermore, the high electron mobility of manganese ions accelerates the deep oxidation of intermediate products, effectively reducing dioxin formation. The combined use of the main and auxiliary phases and the synergistic effect of the elements substantially remove and decompose chloride ions, significantly reducing chlorine poisoning and effectively enhancing the oxidation efficiency of organic gases.

[0039] The precious metal components located deep inside the carrier mesopores have less contact with chloride ions and can fully catalyze the oxidation of hydrocarbon-containing organic gases.

[0040] The catalyst provided in this application has passed pilot testing for the catalytic oxidation of epichlorohydrin tail gas. The tail gas was tested to contain the following components: acrolein, epichlorohydrin, methyl chloride, ethylene oxide, and other impurities, achieving a 100% tail gas purification pass rate. Its stable structure, combined with its resistance to chlorine poisoning and efficient oxidation, have demonstrated excellent performance in practical applications.

[0041] The present application also provides a method for preparing the above-mentioned catalyst for dehydrogenation in a chlorine-containing environment, which comprises the following steps.

[0042] First, prepare the vector:

[0043] S11. Dissolve 1 part zirconium salt solution, 0.5 part magnesium nitrate solution, 1 part ferric nitrate solution, and 1.25-2.5 parts hexadecyltrimethylammonium bromide in an appropriate amount of ethanol in a molar ratio and stir to obtain a mixed solution. The zirconium salt solution is preferably one or more of zirconium nitrate, zirconium chloride, or zirconium oxychloride. These three raw materials provide the zirconium, magnesium, and iron sources required for the support. Hexadecyltrimethylammonium bromide acts as a template to promote the porous structure of the product.

[0044] S12. While the mixed solution is being stirred, ammonia water is added to adjust the pH to 8-10, the temperature is raised to 40-60° C., an appropriate amount of ethylene glycol is added, and the mixture is hydrolyzed for 2-4 hours to obtain a wet gel. The addition of ethylene glycol can slow down the hydrolysis rate and prevent metal precipitation.

[0045] S13, allowing the wet gel to stand and mature at room temperature for 24-48 hours, and then washing the gel with anhydrous ethanol to remove residual nitrate ions, chloride ions and templates.

[0046] S14. Place the gel in a vacuum drying oven and dry at 80-100° C. for 12-24 hours.

[0047] S15. calcining the dried gel at 300-400° C. for 2-4 hours to decompose and remove hexadecyltrimethylammonium bromide, ethylene glycol, etc.; then heating to 550-700° C. and calcining for 4-6 hours to promote the crystal structure of ZrO2 and MgFeO4.

[0048] Based on the above steps, a carrier with a large number of mesopores on the surface is prepared; a carrier with a large number of mesopores on the surface can be prepared according to the above raw material dosage and the method in the prior art, which should also be considered as the scope of protection of this application.

[0049] Then, the noble metal component is confined to grow in the mesopores of the support:

[0050] S21. Select any three or more of a rhodium solution, a ruthenium solution, a platinum solution, a palladium solution, and a gold solution, mix them evenly with an appropriate amount of ethanol, immerse the support in the mixture, and vacuum evaporate for 4 hours to obtain an intermediate product. The vacuum-induced effect causes the noble metal ions to enter the mesopores of the support and aggregate to form nuclei, resulting in noble metal particles distributed within the mesopores of the support.

[0051] S22. The intermediate product is placed in a vacuum environment and dried for more than 24 hours, and then taken out and calcined at 600° C. in a nitrogen atmosphere for 5 hours to obtain a semi-finished catalyst product.

[0052] Finally, the additive is evenly dispersed on the surface of the carrier and in the mesopores:

[0053] S31. Take materials according to the molar ratio, take 2.5-3.5 parts of vanadium aqueous solution, 1 part of tungsten aqueous solution and an appropriate amount of ethanol and mix them evenly, immerse the semi-finished catalyst cooled to room temperature into the mixture, and immerse for 20-24 hours.

[0054] S32, drying at 80-100°C for more than 8 hours, then taking out and calcining at 600°C in a nitrogen atmosphere for 5 hours.

[0055] S33, taking 1.5-2.5 parts of a manganese aqueous solution, 1 part of a cerium aqueous solution and an appropriate amount of ethanol, mix them evenly, immerse the product obtained in step S32 therein, and immerse for 20-24 hours.

[0056] S34. Dry the product obtained in step S33 at 80-100° C. for more than 8 hours, then take it out and calcine it at 600° C. in a nitrogen atmosphere for 5 hours to obtain a finished catalyst for dehydrogenation in a chlorine-containing environment.

[0057] In step S31, the vanadium aqueous solution is preferably one or more of vanadium nitrate and vanadium difluoride; the tungsten aqueous solution is preferably a soluble tungsten-fluoride complex. In step S33, the manganese aqueous solution is preferably one or more of manganese sulfate, manganese nitrate, and manganese acetate; and the cerium aqueous solution is preferably one or more of cerium chloride, cerium sulfate, and cerium nitrate.

[0058] After two impregnation and calcination operations, the main phase and auxiliary phase in the additive are evenly distributed on the surface of the carrier, and the natural impregnation at room temperature ensures that the metal ions in the main phase and auxiliary phase will not cover the entire surface of the carrier, leaving certain gaps, which will not affect the contact between the precious metal components deep in the mesopores, the carrier components and the chlorine-containing organic waste gas.

[0059] The above steps yield a catalyst for dehydrogenation in chlorine-containing environments, exhibiting a stable structure with active ingredient additives on the support surface and precious metal components within the mesopores. The ZrO2-MgFeO4 crystal structure provides a stable granular support with numerous mesopores. The additives V2O5-WO3 and CeO2-MnO2 in the active ingredients are primarily distributed on the support surface, while the precious metal components in the active ingredients are primarily distributed within the mesopores due to vacuum induction. This uniform and dispersed distribution of the active ingredients provides a large specific surface area and numerous active sites. This facilitates rapid contact between chlorine-containing organic gases (hydrocarbons) and the catalyst, resulting in excellent catalytic performance.

[0060] This application also provides the use of the above catalyst in the field of removing chlorine-containing organic tail gas. It is suitable for catalytically removing hydrocarbon organic gases and decomposing chlorine-containing gases in chlorine-containing environments, especially chlorine-containing organic waste gas generated by the production of epichlorohydrin, with excellent catalytic oxidation effect.

[0061] Specifically, a chlorine-containing organic gas is contacted with the above-mentioned catalyst, wherein the chlorine-containing organic gas includes at least epichlorohydrin and monochloromethane; further, the chlorine-containing organic gas includes acrolein, epichlorohydrin, monochloromethane, and ethylene oxide. The use of the catalyst provided herein can avoid poisoning of the catalyst by chloride ions, allowing for the full catalytic decomposition of organic gases and chlorine-containing organic gases, and can also reduce the catalytic reaction temperature. Excellent catalytic decomposition effects can be achieved at a reaction temperature of 250-400°C. The catalytic reaction temperature is more preferably 250-280°C.

[0062] This application does not restrict the catalytic reactor or the position of the catalyst in the reactor. Any structure that allows the raw gas to fully pass through the catalyst is acceptable. The catalytic reactor includes at least an air inlet and an air outlet. The air inlet is used to input the tail gas (raw gas) of the chlorine-containing organic gas, and the air outlet is used to discharge the clean gas (exhaust gas) after catalytic decomposition. The catalytic reactor also includes a heating device and a temperature control device for controlling the reaction temperature of the catalytic process. The air velocity of the catalytic reactor selected in this application is 4500m 3 ·h -1 .

[0063] The activation temperature of the catalyst provided in this application is preferably 200-300°C. Before the catalytic process, the reactor needs to be slowly heated up to keep the catalyst active; first heat it up from room temperature to 150°C, keep it for a certain time until the reactor outlet detects 150°C, and then heat it up again; heat it up from 150°C to 300°C, and keep it for a certain time until the outlet detects 200°C. Continuously detect that the outlet temperature is always above 200°C, and then introduce the raw gas. The temperature of the raw gas is not limited, and this application preferably prefers 40-300°C. The flow rate of the raw gas is preferably 25-40Nm 3 / h.

[0064] During the catalytic reaction, since the feed gas has a certain temperature and the temperature may vary, it is necessary to continuously monitor the reactor outlet temperature to avoid affecting the catalytic effect. If the temperature exceeds 400°C, the catalytic effect has already decreased and is showing a trend of deterioration. It is necessary to stop the feed gas supply and wait until the temperature drops to around 300°C before reintroducing the feed gas.

[0065] The preparation method and actual effect of the catalyst for dehydrogenation in a chlorine-containing environment provided by the present application will be further described below with reference to the examples.

[0066] Example 1:

[0067] First, a carrier with multiple mesopores is prepared:

[0068] S11. Take materials in molar ratios, dissolve 1 part of zirconium nitrate solution, 0.5 parts of magnesium nitrate solution, 1 part of ferric nitrate solution and 1.25 parts of hexadecyltrimethylammonium bromide in an appropriate amount of ethanol, and stir evenly to obtain a mixed solution.

[0069] S12. Keep the mixed solution in a stirring state, add ammonia water to adjust the pH value to 8, raise the temperature to 40° C., add an appropriate amount of ethylene glycol, and carry out hydrolysis reaction for 2 hours to obtain a wet gel.

[0070] S13, leaving the wet gel to mature at room temperature for 24 hours, and then washing the gel with anhydrous ethanol.

[0071] S14. Place the gel in a vacuum drying oven and dry at 80°C for 12 hours.

[0072] S15. The dried gel is calcined at 300° C. for 2 hours to decompose and remove hexadecyltrimethylammonium bromide, ethylene glycol, etc.; then the temperature is raised to 550° C. and calcined for 4 hours to obtain a carrier with a ZrO2-MgFeO4 composite crystal structure.

[0073] Then, the noble metal component is confined to grow in the mesopores of the support:

[0074] S21. Select a rhodium solution, a ruthenium solution, a platinum solution and mix them evenly with an appropriate amount of ethanol, immerse the carrier therein, and vacuum evaporate for more than 4 hours to obtain an intermediate product.

[0075] S22. The intermediate product is placed in a vacuum environment and dried for more than 24 hours, and then taken out and calcined at 600° C. in a nitrogen atmosphere for 5 hours to obtain a semi-finished catalyst product.

[0076] Finally, the additive is evenly dispersed on the surface of the carrier and in the mesopores:

[0077] S31. Take materials according to the molar ratio, take 2.5 parts of vanadium difluoride, 1 part of soluble tungsten fluoride complex and an appropriate amount of ethanol and mix them evenly. After cooling the semi-finished catalyst obtained in step S22 to room temperature, immerse it in the mixture and soak for 20 hours.

[0078] S32, drying at 80°C for 8 hours, then taking out and calcining at 600°C in a nitrogen atmosphere for 5 hours.

[0079] S33, take 1.5 parts of manganese nitrate, 1 part of cerium nitrate and an appropriate amount of ethanol and mix them evenly, immerse the product obtained in step S32 therein, and immerse for 20 hours.

[0080] S34. Dry the product obtained in step S33 at 80° C. for 8 hours, then take it out and calcine it at 600° C. in a nitrogen atmosphere for 5 hours to obtain a finished catalyst for dehydrogenation in a chlorine-containing environment.

[0081] Example 2:

[0082] First, a carrier with multiple mesopores is prepared:

[0083] S11. Take materials in molar ratios, dissolve 1 part of zirconium nitrate solution, 0.5 part of magnesium nitrate solution, 1 part of ferric nitrate solution and 2.5 parts of hexadecyltrimethylammonium bromide in an appropriate amount of ethanol, and stir evenly to obtain a mixed solution.

[0084] S12. Keep the mixed solution in a stirring state, add ammonia water to adjust the pH value to 10, raise the temperature to 60° C., add an appropriate amount of ethylene glycol, and carry out hydrolysis reaction for 4 hours to obtain a wet gel.

[0085] S13, leaving the wet gel to mature at room temperature for 48 hours, and then washing the gel with anhydrous ethanol.

[0086] S14. Place the gel in a vacuum drying oven and dry at 100°C for 24 hours.

[0087] S15. The dried gel is calcined at 400° C. for 4 hours to decompose and remove hexadecyltrimethylammonium bromide, ethylene glycol, etc.; then the temperature is raised to 700° C. and calcined for 6 hours to obtain a carrier with a ZrO2-MgFeO4 composite crystal structure.

[0088] Then, the noble metal component is confined to grow in the mesopores of the support:

[0089] S21. Select a rhodium solution, a palladium solution, and a platinum solution and mix them evenly with an appropriate amount of ethanol, immerse the carrier therein, and vacuum evaporate for 5 hours to obtain an intermediate product.

[0090] S22. The intermediate product is placed in a vacuum environment and dried for 24 hours. Then, the intermediate product is taken out and calcined at 600° C. in a nitrogen atmosphere for 5 hours to obtain a semi-finished catalyst product.

[0091] Finally, the additive is evenly dispersed on the surface of the carrier and in the mesopores:

[0092] S31. Take materials according to the molar ratio, take 3.5 parts of vanadium nitrate, 1 part of soluble tungsten fluoride complex and an appropriate amount of ethanol and mix them evenly. After cooling the semi-finished catalyst obtained in step S22 to room temperature, immerse it in the mixture and soak for 24 hours.

[0093] S32, drying at 100°C for 9 hours, then taking out and calcining at 600°C in a nitrogen atmosphere for 5 hours.

[0094] S33, take 2.5 parts of manganese acetate, 1 part of cerium chloride and an appropriate amount of ethanol and mix them evenly, immerse the product obtained in step S32 therein, and immerse for 24 hours.

[0095] S34. Dry the product obtained in step S33 at 100° C. for 8 hours, then take it out and calcine it at 600° C. in a nitrogen atmosphere for 5 hours to obtain a finished catalyst for dehydrogenation in a chlorine-containing environment.

[0096] Example 3:

[0097] First, a carrier with multiple mesopores is prepared:

[0098] S11. Take materials in molar ratio, dissolve 1 part of zirconium chloride solution, 0.5 part of magnesium nitrate solution, 1 part of ferric nitrate solution and 2 parts of hexadecyltrimethylammonium bromide in an appropriate amount of ethanol, and stir evenly to obtain a mixed solution.

[0099] S12. Keep the mixed solution in a stirring state, add ammonia water to adjust the pH value to 9, raise the temperature to 50° C., add an appropriate amount of ethylene glycol, and carry out hydrolysis reaction for 3 hours to obtain a wet gel.

[0100] S13, leaving the wet gel to mature at room temperature for 36 hours, and then washing the gel with anhydrous ethanol.

[0101] S14. Place the gel in a vacuum drying oven and dry at 90°C for 18 hours.

[0102] S15. The dried gel is calcined at 350° C. for 2.5 hours to decompose and remove hexadecyltrimethylammonium bromide, ethylene glycol, etc.; then the temperature is raised to 600° C. and calcined for 5 hours to obtain a carrier with a ZrO2-MgFeO4 composite crystal structure.

[0103] Then, the noble metal component is confined to grow in the mesopores of the support:

[0104] S21. Select rhodium solution, ruthenium solution, platinum solution, palladium solution, gold solution and mix them evenly with appropriate amount of ethanol, immerse the carrier therein, and vacuum evaporate for more than 4 hours to obtain an intermediate product.

[0105] S22. The intermediate product is placed in a vacuum environment and dried for 24 hours. Then, the intermediate product is taken out and calcined at 600° C. in a nitrogen atmosphere for 5 hours to obtain a semi-finished catalyst product.

[0106] Finally, the additive is evenly dispersed on the surface of the carrier and in the mesopores:

[0107] S31. Take materials according to the molar ratio, take 3 parts of vanadium nitrate, 1 part of soluble tungsten fluoride complex and mix them evenly with an appropriate amount of ethanol, cool the semi-finished catalyst obtained in step S22 to room temperature and immerse it in the mixture for 22 hours.

[0108] S32, drying at 90°C for 8 hours, then taking out and calcining at 600°C in a nitrogen atmosphere for 5 hours.

[0109] S33, take 2 parts of manganese nitrate, 1 part of cerium nitrate and an appropriate amount of ethanol and mix them evenly, immerse the product obtained in step S32 therein, and immerse for 22 hours.

[0110] S34. Dry the product obtained in step S33 at 90° C. for 8 hours, then take it out and calcine it at 600° C. in a nitrogen atmosphere for 5 hours to obtain a finished catalyst for dehydrogenation in a chlorine-containing environment.

[0111] Example 4:

[0112] S11. Select a rhodium solution, a palladium solution, and a gold solution and mix them with an appropriate amount of ethanol, immerse the carrier obtained in Example 1 in the mixture, and vacuum evaporate for 6 hours to obtain an intermediate product.

[0113] S12, placing the intermediate product in a vacuum environment and drying it for 26 hours, then taking it out and calcining it at 600° C. in a nitrogen atmosphere for 5 hours to obtain a semi-finished catalyst product.

[0114] Then, the additive is evenly dispersed on the surface and in the mesopores of the carrier:

[0115] S21. Take materials according to the molar ratio, take 2.8 parts of vanadium nitrate, 1 part of soluble tungsten fluoride complex and an appropriate amount of ethanol and mix them evenly. After cooling the semi-finished catalyst obtained in step S22 to room temperature, immerse it in the mixture and soak for 23 hours.

[0116] S22, drying at 100°C for 8 hours, then taking out and calcining at 600°C in a nitrogen atmosphere for 5 hours.

[0117] S23, take 1.8 parts of manganese sulfate, 1 part of cerium sulfate and an appropriate amount of ethanol and mix them evenly, immerse the product obtained in step S32 therein, and immerse for 22 hours.

[0118] S24, drying the product obtained in step S33 at 95° C. for 12 hours, then taking it out and calcining it at 600° C. in a nitrogen atmosphere for 5 hours to obtain a finished catalyst for dehydrogenation in a chlorine-containing environment.

[0119] Comparative Example 1:

[0120] The catalyst semi-finished product obtained in step S22 of Example 1 was used as a control catalyst. The catalyst also exhibited a porous microsphere structure, and the precious metal components were confined and distributed in the mesopores due to the vacuum effect; it only lacked an additive.

[0121] Comparative Example 2:

[0122] Following the raw material amounts described in Example 1, 1 part zirconium nitrate solution, 0.5 part magnesium nitrate solution, and 1 part ferric nitrate solution were dissolved in deionized water. Ammonia solution (20% by mass) was added, and a colloidal precipitate was obtained by coprecipitation. The precipitate was washed and dried, and then calcined at 550°C for 4 hours to obtain a support. After grinding, the support had a microspherical structure with few surface mesopores, allowing the active ingredient to be dispersed only on the support surface.

[0123] According to the methods and raw materials of steps S21-S22 and S31-S34 in Example 1, the precious metal component, the auxiliary agent main phase and the auxiliary agent subphase are impregnated on the carrier by impregnation method to obtain a catalyst.

[0124] The catalysts obtained in Example 1-2 and Comparative Example 1-2 were tested:

[0125] The total flow rate of raw gas is 40Nm 3 / h, add air 3.5Nm 3 / h, and passed into the catalytic reactor for catalytic reaction; the raw gas includes acrolein, epichlorohydrin, monochloromethane, ethylene oxide and impurity gas, and its initial temperature is 20-35℃. The reaction pressure is micro pressure, the reactor inlet temperature is 210-230℃, and the reactor outlet temperature is 130-160℃. The reactor design space velocity is 4500m 3 ·h -1 .

[0126] Catalysts prepared in Examples 1-4 and Comparative Examples 1-2 were added to a catalytic reactor. Aside from the catalyst type, the catalyst dosage and packing position remained the same. The gas composition and content at the inlet (feed gas) and outlet (exhaust gas) were measured to evaluate the catalytic performance of the catalysts.

[0127] Table 1: Raw gas and exhaust gas test results

[0128]

[0129] From the above table data, it can be seen that the catalysts obtained in Example 1 and Example 2 have extremely high removal rates for organic hydrocarbon gases and chlorine-containing organic gases. The chlorine component in the gas has no effect on the catalytic decomposition process. The organic matter content in the final exhaust gas is less than 120 mg / m 3 , meeting national environmental protection requirements, with a qualified rate of 100%. However, the catalyst provided in Comparative Example 1 lacks the active ingredients of the main phase V2O5-WO3 and the secondary phase CeO2-MnO2, and cannot effectively eliminate the poisoning effect of chloride ions on the precious metal active ingredients, resulting in a significant decrease in catalytic effect. Although the catalyst provided in Comparative Example 2 has the same composition as Example 1, the carrier lacks a mesoporous structure, so that all active ingredients are distributed on the carrier surface. In addition, the multi-step impregnation method may cause a portion of the precious metal active components impregnated first to be covered by the auxiliary active ingredients impregnated later. Therefore, it can be seen that its catalytic effect is reduced, but the reduction is lower than that of Comparative Example 1 (active ingredients are poisoned and cannot function).

[0130] In addition, Table 2 below discloses information on the catalytic effect of the catalyst provided in Example 1 when working for a long time. It can be seen that the catalyst provided in this application is stable in nature and can stably exert its effect during long-term continuous use without slowly deactivating due to chlorine poisoning, and has an excellent catalytic effect.

[0131] Table 2: Test results of raw gas and exhaust gas over time

[0132]

[0133] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A catalyst for dehydrogenation in a chlorine-containing environment, characterized in that: Includes carrier and active ingredient: The carrier includes ZrO2 and MgFeO4; The active ingredients include an auxiliary agent and a precious metal component, the auxiliary agent includes a V2O5-WO3 composite oxide and a CeO2-MnO2 composite oxide, and the precious metal component includes at least three of rhodium, ruthenium, platinum, palladium, and gold; The carrier has mesopores, the noble metal component is distributed in the mesopores, and the auxiliary agent is distributed on the surface of the carrier.

2. The catalyst for dehydrogenation in a chlorine-containing environment according to claim 1, wherein The mass percentage of the active component in the catalyst is 10-50%.

3. The catalyst for dehydrogenation in a chlorine-containing environment according to claim 1, wherein The molar ratio of vanadium to tungsten in the active component is (2.5-3.5):1, the molar ratio of cerium to manganese is 1:(1.5-2.5), and the molar ratio of tungsten to cerium is 1:

1.

4. A method for preparing the catalyst for dehydrogenation in a chlorine-containing environment according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Prepare a carrier with a large number of mesopores on the surface; S2. The carrier is immersed in a precious metal solution, vacuum evaporated, dried, and calcined to distribute the precious metal ions in the mesopores of the carrier to obtain a semi-finished product; S3. Immerse the semi-finished product in a mixed solution of vanadium and tungsten, dry it, and then calcine it; then immerse it in a mixed solution of manganese and cerium, dry it, and then calcine it to obtain a finished catalyst.

5. The method according to claim 4, characterized in that Step S1 includes the following steps: S11. The zirconium salt solution, magnesium nitrate solution, ferric nitrate solution and cetyltrimethylammonium bromide were dissolved in ethanol and stirred; S12. Ammonia was added to adjust the pH to 8-10, and then the temperature was raised to 40-60 ° C and ethylene glycol was added. The hydrolysis reaction was carried out for 2-4 hours to obtain a wet gel; S13. The wet gel was aged at room temperature for 24-48 h, then washed and vacuum dried at 80-100 ° C for 12-24 h; S14. Calcinate at 300-400℃ for 2-4h, then raise the temperature to 550-700℃ and calcine for 4-6h.

6. The method according to claim 4, characterized in that In step S2, the precious metal solution includes at least three of rhodium solution, ruthenium solution, platinum solution, palladium solution, and gold solution, is vacuum evaporated for 4 hours, vacuum dried for more than 24 hours, and calcined at 600° C. in a nitrogen atmosphere for 5 hours.

7. The method according to claim 4, characterized in that In step S3, the immersion temperature is room temperature; the drying temperature is 80-100° C. and the time is more than 8 hours; and the calcination temperature in a nitrogen atmosphere is 600° C. and the time is 5 hours.

8. Use of the catalyst for dehydrogenation in a chlorine-containing environment according to any one of claims 1 to 3 or the catalyst prepared by the method according to any one of claims 4 to 7 in removing chlorine-containing organic matter.

9. The use according to claim 8, characterized in that The chlorine-containing organic matter includes at least one of epichlorohydrin and monochloromethane.

10. Use of the catalyst for dehydrogenation in a chlorine-containing environment according to any one of claims 1 to 3 or the catalyst prepared by the method according to any one of claims 4 to 7 in removing organic matter.

11. The use according to claim 10, characterized in that The organic matter includes at least one of acrolein and ethylene oxide.

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