Catalytic combustion catalysts for chlorine-containing vocs and methods of making and using the same
By loading organic titanium and Ru onto a titanium dioxide support and supplementing them with Co, Ce, and Sn to form a TiOx coating, the problem of catalyst susceptibility to chlorine poisoning and the generation of polychlorinated byproducts is solved, achieving high activity and low byproduct formation. This method is suitable for industrial treatment of chlorine-containing volatile organic compounds.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ZHEJIANG UNIV
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-09
AI Technical Summary
Existing catalytic combustion methods for treating chlorinated volatile organic compounds (CVOCs) suffer from catalyst poisoning by chlorine, resulting in the formation of polychlorinated byproducts and dioxins, and also exhibit insufficient stability and selectivity.
By loading organic titanium and active metal Ru onto a titanium dioxide support, and supplementing it with additives Co, Ce, and Sn, a TiOx coating layer is formed after calcination in an inert atmosphere and air, thereby improving the catalyst's resistance to chlorine and water and its selectivity.
It achieves high activity, high stability, and low by-product formation, reduces dioxin formation, and has a simple and low-cost preparation method, making it suitable for industrial applications.
Smart Images
Figure CN122164399A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of waste gas purification and treatment technology, and in particular to a chlorine-containing VOCs catalytic combustion catalyst, its preparation method, and its application. Background Technology
[0002] Chlorine-containing volatile organic compounds (CVOCs) are widely used in industries such as petrochemicals, chlor-alkali chemicals, pharmaceuticals, and coatings. However, CVOCs are characterized by high toxicity, high stability, and difficulty in degradation, exhibiting strong carcinogenic, teratogenic, and mutagenic effects. Their release into the atmosphere poses a serious threat to the environment and human health. Given the widespread application and irreplaceable nature of CVOCs, post-treatment methods are the primary means of reducing CVOC pollution.
[0003] Currently, adsorption, absorption, direct incineration, photocatalytic degradation, catalytic combustion, or a combination of these methods are the main approaches for recovering or completely eliminating CVOCs. Among them, catalytic combustion technology has the advantages of low energy consumption, wide applicability, and high removal efficiency, and has been widely studied and applied in VOCs purification.
[0004] In the catalytic combustion method for removing CVOCs, the inorganic chlorine generated during the reaction can easily lead to chlorine poisoning of the catalyst and the formation of polychlorinated byproducts, and even highly toxic organic compounds such as dioxins, which are environmentally unfriendly. Therefore, developing highly active, stable, and selective CVOCs catalysts is crucial for the practical application of this technology.
[0005] Chinese patent CN 113426458 B discloses a catalyst for the catalytic combustion of halogen-containing volatile organic compounds and its applications. The catalyst precipitates active components onto a high-viscosity coating surface via a redox method, wherein the active components consist of the noble metal ruthenium and the transition metals iron and manganese. The catalyst exhibits high stability, regenerability, and high moisture resistance, high conversion efficiency for halogen-containing volatile organic compounds, and low preparation cost.
[0006] Chinese Patent CN 107008459 B discloses a catalyst for the low-temperature catalytic combustion of chlorinated organic compounds, its preparation method, and its application. The catalyst is a sulfuric acid-modified transition metal oxide; wherein the sulfuric acid exists on the surface of the transition metal oxide in the form of bidentate sulfate, and the transition metal oxide is zirconium oxide, titanium oxide, or iron oxide. The catalyst not only exhibits high catalytic activity, enabling the combustion and oxidation of chlorinated organic compounds at relatively low temperatures without the formation of secondary polluting chlorinated products, but also boasts a simple preparation method, low cost, and long service life.
[0007] Although the above catalysts have certain catalytic activity, their low-temperature activity, chlorine resistance, water resistance, and ability to inhibit polychlorinated byproducts need to be improved. Summary of the Invention
[0008] This invention provides a chlorine-containing VOCs catalytic combustion catalyst and its preparation method. The catalyst preparation method is simple and exhibits advantages such as high catalytic activity, high chlorine and water resistance, high selectivity, and extremely low dioxin formation in CVOCs catalytic combustion reactions.
[0009] The technical solution of the present invention is as follows: A method for preparing a chlorine-containing VOCs catalytic combustion catalyst includes the following steps: (1) Loading organotitanium and active metal precursors onto titanium dioxide; or loading organotitanium, active metal precursors and auxiliary metal precursors onto titanium dioxide; The active metal is Ru, and the auxiliary metals are Co, Ce, and Sn; (2) After drying, inert atmosphere calcination and air calcination in sequence, a chlorine-containing VOCs catalytic combustion catalyst is obtained.
[0010] When the loading of active metal is too low, the catalytic activity of the catalyst is low; when the loading of active metal is too high, the improvement on the catalytic activity of the catalyst is minimal and the cost is too high.
[0011] Preferably, the loading of active metal is 0.3wt% to 1.5wt% based on the raw materials.
[0012] Preferably, the precursor of the active metal is at least one of the nitrate, chlorate, and chloride salts of the active metal.
[0013] Additive metals can improve catalyst activity to some extent, but excessive loading will inhibit the catalyst's catalytic activity.
[0014] Preferably, the loading of the auxiliary metal is 0wt% to 5wt% based on the raw material.
[0015] Preferably, the precursor of the active metal is at least one of the nitrate, acetate, and chloride salts of the auxiliary metal.
[0016] After calcination in an inert atmosphere and in air, organotitanium forms a TiOx coating on the surface of the active metal and the auxiliary metal. This coating can exist stably under oxygen-containing high-temperature conditions, giving the catalyst good resistance to chlorine and water.
[0017] Preferably, the loading of organotitanium is 1.0wt% to 5.0wt% based on the raw material.
[0018] When the loading of organotitanium is too low, an effective coating layer cannot be formed; when the loading of organotitanium is too high, the coating layer is too thick, which will inhibit the catalytic activity of the catalyst.
[0019] More preferably, the loading of organotitanium is 1.5wt% to 2.0wt% based on the raw material.
[0020] Preferably, the organotitanium is at least one of di(2-hydroxypropionic acid)diammonium hydroxide titanium and (triethanolamine)isopropoxide titanium (IV).
[0021] Preferably, step (1) includes: An impregnation solution is prepared by mixing and dissolving organic titanium and active metal precursors, and titanium dioxide is impregnated into the impregnation solution in an equal volume. Alternatively, an impregnation solution can be prepared by mixing and dissolving organic titanium, an active metal precursor, and an auxiliary metal precursor, and then impregnating an equal volume of titanium dioxide into the impregnation solution.
[0022] Preferably, the inert atmosphere is at least one of nitrogen, argon, and helium.
[0023] Preferably, the inert atmosphere calcination temperature is 350℃~450℃, and the calcination time is 2~5h.
[0024] Further preferred, the inert atmosphere calcination temperature is 380℃~410℃, and the calcination time is 3~5h.
[0025] Preferably, the air calcination temperature is 350℃~450℃ and the calcination time is 2~5h.
[0026] Further preferably, the air calcination temperature is 380℃~410℃, and the calcination time is 3~5h.
[0027] Preferably, the heating rate during the inert atmosphere roasting stage and the air roasting stage is 3~7℃ / min.
[0028] The preparation method of this invention involves supporting organotitanium, calcining in an inert atmosphere, and calcining in air to form a special encapsulation structure on the catalyst surface. This encapsulation structure can exist stably under high-temperature oxygen and water-containing conditions, enabling the catalyst prepared by this invention to exhibit high activity, high stability (chlorine and water resistance), and high selectivity (lower polychlorinated byproducts and dioxin formation) in CVOCs catalytic combustion reactions. Furthermore, the preparation method of this invention is simple, low-cost, and has good prospects for engineering applications.
[0029] The present invention also provides a chlorine-containing VOCs catalytic combustion catalyst, which is prepared by the above preparation method.
[0030] The present invention also provides the application of the chlorine-containing VOCs catalytic combustion catalyst in the catalytic combustion degradation reaction of chlorine-containing VOCs.
[0031] Preferably, the application includes: filling the chlorine-containing VOCs catalytic combustion catalyst into a fixed-bed reactor and introducing chlorine-containing VOCs gas; the total gas flow rate is 10~200 ml / min, the total volume hourly space velocity is 10000~50000 ml / (gcat·h); and the reaction temperature is 200~400℃.
[0032] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The chlorine-containing VOCs catalytic combustion catalyst of the present invention has the advantages of high activity, high stability (chlorine and water resistance) and high selectivity (lower polychlorinated byproducts and dioxin formation) in CVOCs catalytic combustion.
[0033] (2) The catalyst preparation method of the present invention is simple, the raw materials are inexpensive, and it is easy to prepare on a large scale, and has good industrial application prospects. Attached Figure Description
[0034] Figure 1 CO-DRIFT spectra of the catalysts in Example 1 and Comparative Example 1; Figure 2 TEM image of Example 1; Figure 3 This is a TEM image of Comparative Example 1. Detailed Implementation
[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not limit it in any way.
[0036] Example 1 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide powder carrier, and add the impregnation solution dropwise onto the titanium dioxide surface for equal-volume impregnation while stirring. After the addition is complete, the catalyst is left to stand for 10 h, and then dried in an oven at 80 °C for 10 h. Subsequently, the catalyst is placed in a tube furnace and calcined at 400 °C for 4 h under nitrogen atmosphere. Finally, the catalyst is calcined in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0037] Example 2 Weigh 0.625 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0038] Compared to Example 1, the Ru loading is halved, and its loading is 0.5 wt%.
[0039] Example 3 Weigh 1.875 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, the catalyst is left to stand for 10 h, and then dried in an oven at 80 °C for 10 h. Subsequently, the catalyst is placed in a tube furnace and calcined at 400 °C for 4 h under nitrogen atmosphere. Finally, the catalyst is calcined in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0040] Compared to Example 1, the Ru loading is 1.5 wt%.
[0041] Example 4 1.875 g of ruthenium nitrate solution (8% Ru concentration) and 0.246 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide were weighed and dissolved in 4.5 g of deionized water. After stirring for 30 min, an impregnation solution was obtained. 10 g of anatase titanium dioxide was weighed and the impregnation solution was added dropwise to the surface of the titanium dioxide while stirring. After the addition was complete, the catalyst was left to stand for 10 h and then dried in an oven at 80 °C for 10 h. Subsequently, the catalyst was placed in a tube furnace and calcined at 400 °C for 4 h under nitrogen atmosphere. Finally, the catalyst was calcined in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0042] Compared to Example 1, the organic titanium loading was doubled to 2.0 wt%.
[0043] Example 5 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.15 g of triethanolamine isopropoxide titanium(IV), dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0044] Compared to Example 1, the organic titanium-supported precursor has been changed.
[0045] Example 6 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration), 0.123 g of diammonium di(2-hydroxypropionic acid)dihydroxide titanium dioxide, and 0.493 g of cobalt nitrate hexahydrate, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0046] Example 7 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration), 0.123 g of diammonium di(2-hydroxypropionic acid)dihydroxide titanium dioxide, and 1.48 g of cobalt nitrate hexahydrate, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0047] Example 8 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration), 0.123 g of diammonium di(2-hydroxypropionic acid) hydroxide titanium dioxide, and 0.174 g of stannous oxalate, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0048] Example 9 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration), 0.123 g of diammonium di(2-hydroxypropionic acid) hydroxide titanium dioxide, and 0.522 g of stannous oxalate, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0049] Example 10 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration), 0.123 g of diammonium di(2-hydroxypropionic acid)dihydroxide titanium dioxide, and 0.301 g of cerium nitrate hexahydrate, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0050] Example 11 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration), 0.123 g of diammonium di(2-hydroxypropionic acid)dihydroxide titanium dioxide, and 0.903 g of cerium nitrate hexahydrate, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0051] Example 12 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 350 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0052] Example 13 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 350 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0053] Example 14 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 350 °C under air atmosphere for 4 h.
[0054] Example 15 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, place the catalyst in a tube furnace and calcine it at 400 °C for 4 h under nitrogen atmosphere. Finally, calcine the catalyst in a muffle furnace at 450 °C under air atmosphere for 4 h.
[0055] Comparative Example 1 1.25 g of ruthenium nitrate solution (8% Ru concentration) was weighed and dissolved in 4.5 g of deionized water. After stirring for 30 min, an impregnation solution was obtained. 10 g of anatase titanium dioxide was weighed and the impregnation solution was added dropwise to the surface of the titanium dioxide while stirring. After the addition was complete, the catalyst was left to stand for 10 h, and then dried in an oven at 80 °C for 10 h. Subsequently, the catalyst was placed in a tube furnace and calcined at 400 °C for 4 h under nitrogen atmosphere. Finally, the catalyst was calcined in a muffle furnace at 400 °C under air atmosphere for 4 h.
[0056] Comparative Example 2 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, calcine the catalyst in a muffle furnace at 400 °C under air for 4 h.
[0057] Comparative Example 3 Weigh 1.25 g of ruthenium nitrate solution (8% Ru concentration) and 0.123 g of di(2-hydroxypropionic acid)diammonium hydroxide titanium dioxide, dissolve them in 4.5 g of deionized water, and stir for 30 min to obtain an impregnation solution. Weigh 10 g of anatase titanium dioxide and add the impregnation solution dropwise onto the surface of the titanium dioxide while stirring. After the addition is complete, let the catalyst stand for 10 h, then dry it in an oven at 80 °C for 10 h. Subsequently, calcine the catalyst in a muffle furnace at 400 °C under air for 4 h, and then calcine it in a tube furnace under nitrogen at 400 °C for 4 h.
[0058] In-situ CO adsorption diffuse reflectance infrared spectroscopy (CO-DRIFT) is a common characterization experiment, mainly used to indirectly explain the formation of encapsulation structures. When encapsulation structures form on the catalyst surface, the adsorption of small molecules such as CO and H2 on the catalyst surface will decrease significantly.
[0059] CO-DRIFT characterization method: A Nicolet 6700 infrared spectrometer was used for testing. The sample was pretreated in a nitrogen flow of 30 mL / min at 200 °C for 1 hour, and then cooled to 30 °C before recording the background spectrum. At 30 °C, the nitrogen gas was switched to a 1% CO / N2 mixture for 30 minutes, followed by a switch back to nitrogen for 30 minutes, with simultaneous infrared spectrum recording.
[0060] 2130~2170 cm -1 The spectrum represents the characteristic peak range of CO adsorption on the Ru / TiO2 surface. After nitrogen stripping, the CO adsorption characteristic peaks essentially disappeared. Furthermore, almost no obvious CO adsorption characteristic peaks were observed in Example 1, while those in Comparative Example 1 reappeared. This spectrum indirectly indicates that an amorphous TiOx thin layer appeared on the surface of Example 1, significantly suppressing CO adsorption.
[0061] TEM images of the catalysts prepared in Example 1 and Comparative Example 1 are shown below. Figure 2 and Figure 3 As shown. Figure 2An amorphous encapsulation structure can be visually observed on the surfaces of Ru and the TiO2 support, indicating that the catalyst prepared in Example 1 formed an encapsulation structure. In contrast, Figure 3 No encapsulation structures could be observed on the catalyst surface.
[0062] Catalyst activity evaluation: 200 mg of the catalysts prepared in Examples 1-15 and Comparative Examples 1-3 were weighed and placed into fixed-bed reactors respectively. A mixture of dichloromethane and air at 1000 ppm was introduced, with a total gas flow rate of 100 ml / min and a total volume hourly space velocity of 30000 ml / (g cat·h). The concentrations of dichloromethane at the inlet and outlet were measured using a gas chromatograph.
[0063] The conversion rate of the corresponding substances was calculated based on the change in net outlet concentration. Starting from 150℃, the concentrations of dichloromethane and polychlorinated byproducts in the reactor tail gas were measured under different reaction temperature conditions. The conversion rate was calculated based on the change in dichloromethane concentration. The temperatures at which the dichloromethane conversion rates were 50% and 90% were recorded, denoted as T. 50 and T 90 .
[0064] The evaluation results of the catalyst are shown in Table 1.
[0065] Table 1 Selectivity of polychlorinated byproducts: Following the activity evaluation experimental conditions described above, the selectivity of the catalysts involved in Examples 1-15 and Comparative Examples 1-3 to polychlorinated byproducts was tested under conditions of 1000 ppm dichloromethane and air at 280°C. The selectivity results are shown in Table 2 below.
[0066] Table 2 Catalyst stability: According to the above-mentioned activity evaluation experimental conditions, the catalysts involved in Example 1, Example 4, Example 6 and Comparative Example 2 were continuously reacted for 200 h in 1000 ppm dichloromethane, 5% water vapor and air at 300 °C. The change of catalyst activity over time was tested, and the results are shown in Table 3.
[0067] Table 3 Dioxin formation in exhaust gas: According to the above-mentioned activity evaluation experimental conditions, the catalysts involved in Example 1 and Comparative Example 2 were continuously reacted for 48 hours under the conditions of 1000ppm dichloromethane, 5% water vapor and air at 300°C. The tail gas was passed into a pesticide residue grade toluene solution to adsorb the dioxins in the tail gas. The content of dioxins in the tail gas was calculated based on the total amount of dioxins absorbed. The results are shown in Table 4.
[0068] Table 4 Comparing the data in Table 1, it can be seen that the catalyst prepared using the technical solution of this invention exhibits higher catalytic activity towards dichloromethane due to its encapsulation structure, and the addition of promoters can also improve the catalyst activity. Comparing the data in Table 2, it can be seen that the catalyst prepared using the technical solution of this invention can significantly inhibit the formation of polychlorinated byproducts. Comparing the data in Table 3, it can be seen that due to the special encapsulation structure of the catalyst prepared using the technical solution of this invention, the catalyst exhibits high resistance to chlorine and water. Comparing the data in Table 4, it can be seen that the dioxin content in the exhaust gas treated by the catalyst prepared using the technical solution of this invention is significantly reduced.
[0069] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a chlorine-containing VOCs catalytic combustion catalyst, characterized in that, Includes the following steps: (1) Loading organotitanium and active metal precursors onto titanium dioxide; or loading organotitanium, active metal precursors and auxiliary metal precursors onto titanium dioxide; The active metal is Ru, and the auxiliary metals are Co, Ce, and Sn; (2) After drying, inert atmosphere calcination and air calcination in sequence, a chlorine-containing VOCs catalytic combustion catalyst is obtained.
2. The method for preparing the chlorine-containing VOCs catalytic combustion catalyst according to claim 1, characterized in that, In step (1), the loading of active metal is 0.3wt%~1.5wt% based on raw materials.
3. The method for preparing the chlorine-containing VOCs catalytic combustion catalyst according to claim 1, characterized in that, In step (1), the loading of the auxiliary metal is 0wt%~5wt% based on the raw materials.
4. The method for preparing the chlorine-containing VOCs catalytic combustion catalyst according to claim 1, characterized in that, In step (1), the loading of organic titanium is 1.0wt%~5.0wt% based on raw materials.
5. The method for preparing the chlorine-containing VOCs catalytic combustion catalyst according to claim 1 or 4, characterized in that, The organic titanium is at least one of di(2-hydroxypropionic acid)diammonium hydroxide titanium and (triethanolamine)isopropoxide titanium (IV).
6. The method for preparing the chlorine-containing VOCs catalytic combustion catalyst according to claim 1, characterized in that, The inert atmosphere calcination temperature is 350℃~450℃, and the calcination time is 2~5h.
7. The method for preparing the chlorine-containing VOCs catalytic combustion catalyst according to claim 1, characterized in that, The air-roasting temperature is 350℃~450℃, and the roasting time is 2~5h.
8. A catalytic combustion catalyst for chlorine-containing VOCs, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 7.
9. The application of the chlorine-containing VOCs catalytic combustion catalyst of claim 8 in the chlorine-containing VOCs catalytic combustion degradation reaction.