Denitration and dioxin removal integrated catalytic fiber and catalytic filter bag

Abstract

The application provides a denitration and dioxin integrated catalytic fiber and a catalytic filter bag, wherein the catalytic fiber comprises PTFE fibers and a catalyst loaded on the PTFE fibers; the catalyst is a molecular sieve coated with a silicon dioxide layer as a carrier, a manganese-copper composite oxide as an active catalytic component and a nickel-cobalt composite oxide as a catalytic component. The catalytic fiber is prepared into the catalytic filter bag, which can effectively realize the synergistic removal of nitrogen oxides and dioxins, and has the advantages of high removal efficiency, good durability and simple preparation process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas purification, and in particular to a denitration and dioxin removal integrated catalytic fiber and a catalytic filter bag. BACKGROUND

[0002] With the rapid development of urban economy, the continuous increase of energy consumption, the rapid growth of motor vehicle ownership and the rapid increase of municipal solid waste production, the air pollution situation presents a mixed pollution of coal smoke and motor vehicle exhaust. Nitrogen oxides (NO x ) mainly come from motor vehicle exhaust, industrial and thermal power plant emissions, etc. 62% of NO x in traffic sources comes from diesel vehicle exhaust emissions. NO x As a primary pollutant, it can directly harm human health; dioxins (PCDD / Fs) are the general term for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzo furans (PCDFs), mainly from waste incineration, metal smelting, chlorinated compound production and pesticide use, of which waste incineration accounts for more than 90% of the total PCDD / Fs, and is the main source of PCDD / Fs pollution. PCDD / Fs have high toxicity, accumulation, biological accumulation and long-distance migration. Due to its special properties of high toxicity and difficult degradation, the accumulation of PCDD / Fs in the environment is increasing, which seriously pollutes the atmosphere, soil and water environment on which human beings depend. Therefore, how to effectively control the content of nitrogen oxides and dioxins in flue gas emissions has been the focus of research in the environmental protection field.

[0003] With the development of industrial flue gas treatment technology, multi-pollutant co-treatment has become the development trend of industrial flue gas treatment technology, mainly reflected in the synergy between denitration and dioxin removal technologies, and the realization of multi-pollutant co-treatment through the combination of multiple functions in the same product.

[0004] The preparation method of a filter material with denitration and dioxin removal functions disclosed in Chinese patent CN112717556A sprays high-temperature denitration and dioxin removal catalyst nanoparticles on each layer of the laid net during the net stacking process of the traditional needle punching filter material production process, so that the catalyst nanoparticles partially melt the fiber body after contacting the fiber, and the nanoparticles are partially fused with the fiber body and have a certain bonding force, forming a nanoparticle composite fiber. The filter material with denitration and dioxin removal functions is prepared through processes such as needle punching, singeing, polishing and heat setting. The preparation process of this dust removal filter material is long and complex, and the efficiency of denitration and dioxin removal is limited. SUMMARY

[0005] Based on the technical problems existing in the background art, the application provides a denitration and dioxin integrated catalytic fiber and a catalytic filter bag, which are prepared into the catalytic filter bag, can effectively realize the synergistic removal of nitrogen oxides and dioxins, and have the advantages of high removal efficiency, good durability and simple preparation process.

[0006] The application provides a denitration and dioxin integrated catalytic fiber, which comprises a PTFE fiber and a catalyst supported on the PTFE fiber.

[0007] The catalyst is a molecular sieve coated with a silica layer as a carrier, a manganese-copper composite oxide as an active catalytic component and a nickel-cobalt composite oxide as a catalytic component.

[0008] In the application, the catalyst is supported on the PTFE fiber to form a catalytic fiber, and then a catalytic filter bag with the functions of denitration and dioxin removal is prepared; the catalyst is a molecular sieve coated with a silica layer as a carrier, the surface of the molecular sieve is coated with a silica layer, the high surface area and pore volume characteristics of the molecular sieve itself are maintained, the silica layer coated on the surface of the molecular sieve provides silanol groups for improving the dispersion of the catalytic component, the metal active component is conveniently deposited, and high catalytic activity is obtained; at the same time, the catalyst uses a manganese-copper composite oxide as an active catalytic component and a nickel-cobalt composite oxide as a catalytic component, the composite oxides have excellent redox performance and oxygen storage and release performance, and can effectively catalyze and remove atmospheric pollutants such as nitrogen oxides and dioxins.

[0009] Preferably, the molecular sieve coated with a silica layer is obtained by reacting a molecular sieve with an alkali silicate under acidic conditions.

[0010] Preferably, the weight of the silica layer is 5-20 wt% of the molecular sieve.

[0011] Preferably, the molecular sieve is at least one of Y-type molecular sieve, SAPO series molecular sieve or MCM series molecular sieve.

[0012] In the catalyst, the content of manganese oxide is 5-15 wt%, the content of copper oxide is 1-7 wt%, the content of nickel oxide is 0.5-5 wt%, and the content of cobalt oxide is 0.5-3 wt%.

[0013] Preferably, the preparation method of the catalytic fiber comprises the following steps:

[0014] S1, precursor of manganese, copper, nickel and cobalt and acid reagent are added into water to obtain a precursor solution, the molecular sieve coated with a silica layer is immersed in the precursor solution, dried, calcined, and then a catalyst is obtained;

[0015] S2, after the catalyst is ground into powder, the catalyst is added into a binder to obtain a catalyst emulsion, the catalyst emulsion is sprayed on the PTFE fiber, and then the PTFE fiber is subjected to swelling treatment, so that the denitration and dioxin integrated catalytic fiber is obtained.

[0016] In the present application, the catalyst component is loaded on a specific carrier by impregnation, drying and calcination to obtain a catalyst, the catalyst and a binder are mixed, the catalyst is adsorbed on the surface of the PTFE fiber by spraying, and then the PTFE fiber is subjected to swelling deformation, so that the volume of the PTFE fiber is increased to form a porous structure, which is helpful for filling the catalyst into the porous structure, and finally a closely integrated catalytic fiber is prepared.

[0017] Preferably, in step S1, the manganese precursor is manganese nitrate or manganese chloride, the copper precursor is copper nitrate or copper chloride, the nickel precursor is nickel nitrate, and the cobalt precursor is cobalt nitrate; and the acid reagent is citric acid.

[0018] Preferably, in step S1, the drying temperature is 80-100℃, and the drying time is 5-12h; and the calcination temperature is 500-600℃, and the calcination time is 2-4h.

[0019] Preferably, in step S2, the binder is a solution comprising methyl acrylate and ammonium chloride.

[0020] Preferably, in step S2, the swelling treatment temperature is 300-400℃, and the swelling treatment time is 3-5h.

[0021] The present application also provides a catalytic filter bag which is sewn by needle-punched felt filter cloth, and the needle-punched felt filter cloth comprises the catalytic fiber.

[0022] The present application also provides an application of the catalytic filter bag in flue gas denitration and dioxin removal.

[0023] The present application loads the catalyst on the PTFE fiber to obtain the catalytic fiber, and the catalytic fiber is woven and sewn to obtain the catalytic filter bag, which can be directly applied in the existing dust removal process without changing the original equipment and working conditions, so that the selective catalytic degradation of nitrogen oxides and dioxin substances can be completed.

[0024] Meanwhile, the present application uses the molecular sieve coated with a silica layer as a catalyst carrier, and loads manganese-copper composite oxides and nickel-cobalt composite oxides on the carrier, so that excellent denitration and dioxin removal effects can be achieved at low temperature through the synergistic effect between the metal composite oxides and the molecular sieve carrier coated with a silica layer. DETAILED DESCRIPTION

[0025] The technical solutions of the present application will be described in detail below through specific embodiments, but it should be made clear that these embodiments are used for illustration only, but not to be interpreted as limiting the scope of the present application.

[0026] Embodiment 1

[0027] A denitration and dioxin integrated catalytic fiber, and a preparation method thereof, comprises the following steps:

[0028] S1, Y-type molecular sieve is added to water, and after stirring uniformly, a slurry is formed; then the slurry is heated to 90℃, and then a sodium silicate solution (10wt% SiO2) with a weight of 1 times that of the Y-type molecular sieve is slowly added; after stirring and mixing uniformly, hydrochloric acid is added to adjust the pH to 6.5; after aging for 1h, drying is performed; and then calcination is performed at 300℃ for 3h, to obtain a molecular sieve coated with a silicon dioxide layer;

[0029] Manganese nitrate, copper nitrate trihydrate and citric acid monohydrate with a weight ratio of 10:4:30 are added to deionized water, and stirring is performed at room temperature until the solution is clear and transparent; then nickel nitrate hexahydrate with a weight of 30% of the manganese nitrate and cobalt nitrate hexahydrate with a weight of 10% of the manganese nitrate are added, and stirring is continued until the solution is clear and transparent, to obtain a precursor solution; the molecular sieve coated with a silicon dioxide layer with a weight of 4 times that of the manganese nitrate is immersed in the precursor solution, and then drying is performed at 90℃ for 10h, and then calcination is performed at 550℃ for 3h, to obtain a catalyst;

[0030] S2, the catalyst is crushed and ground into a powder with an average particle size of 150nm; then the powder is added to a binder composed of 80wt% methyl acrylate and 5wt% ammonium chloride solution, according to a weight ratio of 2:1; after stirring and mixing uniformly, a catalyst emulsion is obtained;

[0031] The catalyst emulsion is uniformly sprayed on a PTFE fiber substrate, so that 5g of the catalyst is contained on every 1kg of the PTFE fiber; then sintering is performed at 350℃ for 4h; after cooling to room temperature, the PTFE fiber is washed with deionized water until clean; and then drying is performed, to complete the puffing treatment, and to obtain the denitration and dioxin integrated catalytic fiber.

[0032] Embodiment 2

[0033] A denitration and dioxin integrated catalytic fiber, and a preparation method thereof, comprises the following steps:

[0034] S1, SAPO-11 molecular sieve is added to water, and after stirring uniformly, a slurry is formed; then the slurry is heated to 90℃, and then a sodium silicate solution (10wt% SiO2) with a weight of 1.5 times that of the Y-type molecular sieve is slowly added; after stirring and mixing uniformly, hydrochloric acid is added to adjust the pH to 6.5; after aging for 1h, drying is performed; and then calcination is performed at 350℃ for 3h, to obtain a molecular sieve coated with a silicon dioxide layer;

[0035] Manganese nitrate, copper nitrate trihydrate and citric acid monohydrate with a weight ratio of 10:5:30 are added to deionized water, stirred at room temperature until the solution is clear and transparent, then 20% by weight of manganese nitrate of nickel nitrate hexahydrate and 20% by weight of manganese nitrate of cobalt nitrate hexahydrate are added, and continue to stir until the solution is clear and transparent to obtain a precursor solution; the molecular sieve coated with a silica layer with 4 times the weight of manganese nitrate is immersed in the precursor solution, dried at 100°C for 6h, and then calcined at 600°C for 2h to obtain a catalyst;

[0036] S2, the catalyst is crushed and ground into a powder with an average particle size of 150nm, then the obtained powder is added to a binder composed of 80wt% methyl acrylate and 5wt% ammonium chloride solution in a weight ratio of 2:1, stirred and mixed uniformly to obtain a catalyst emulsion;

[0037] The catalyst emulsion is uniformly sprayed on the PTFE fiber substrate so that 5g of catalyst is contained on every 1kg of PTFE fiber, and then sintered at 400°C for 3h, cooled to room temperature, washed with deionized water, dried and then the swelling treatment is completed to obtain the denitration and dioxin integrated catalytic fiber.

[0038] Example 3

[0039] A denitration and dioxin integrated catalytic fiber, the preparation method comprising:

[0040] S1, Y-type molecular sieve is added to water, stirred uniformly to form a slurry, heated to 90°C, then slowly added with 1 times the weight of sodium silicate aqueous solution (10wt% SiO2) of Y-type molecular sieve, stirred and mixed uniformly, then adjusted with hydrochloric acid to pH 6.5, aged for 1h, dried, and calcined at 300°C for 3h to obtain a molecular sieve coated with a silica layer;

[0041] Manganese nitrate, copper nitrate trihydrate and citric acid monohydrate with a weight ratio of 10:3:30 are added to deionized water, stirred at room temperature until the solution is clear and transparent, then 50% by weight of manganese nitrate of nickel nitrate hexahydrate and 20% by weight of manganese nitrate of cobalt nitrate hexahydrate are added, and continue to stir until the solution is clear and transparent to obtain a precursor solution; the molecular sieve coated with a silica layer with 4 times the weight of manganese nitrate is immersed in the precursor solution, dried at 80°C for 12h, and then calcined at 500°C for 4h to obtain a catalyst;

[0042] S2, the catalyst is crushed and ground into a powder with an average particle size of 150nm, then the obtained powder is added to a binder composed of 80wt% methyl acrylate and 5wt% ammonium chloride solution in a weight ratio of 2:1, stirred and mixed uniformly to obtain a catalyst emulsion;

[0043] The catalyst emulsion is uniformly sprayed on the PTFE fiber substrate, so that 5 grams of catalyst are contained on every 1 kilogram of PTFE fiber, and then sintering is performed at 300 DEG C for 5 hours; after cooling to room temperature, clean washing is performed with deionized water, and after drying, the puffing treatment is completed, and the denitration and dioxin integrated catalytic fiber is obtained.

[0044] Comparative Example 1

[0045] A denitration and dioxin integrated catalytic fiber, and a preparation method thereof, are disclosed.

[0046] S1, manganese nitrate, copper nitrate trihydrate and citric acid monohydrate in a weight ratio of 10:4:30 are added to deionized water, and stirring is performed at room temperature until the solution is clear and transparent; then, nickel nitrate hexahydrate in an amount of 30% by weight of manganese nitrate and cobalt nitrate hexahydrate in an amount of 10% by weight of manganese nitrate are added, and stirring is continued until the solution is clear and transparent, to obtain a precursor solution; Y-type molecular sieve in an amount of 4 times the weight of manganese nitrate is immersed in the precursor solution, drying is performed at 90 DEG C for 10 hours, and then calcination is performed at 550 DEG C for 3 hours, to obtain a catalyst;

[0047] S2, the catalyst is crushed and ground into a powder with an average particle size of 150 nm, and then the powder is added to a binder composed of 80 wt% of methyl acrylate and 5 wt% of an ammonium chloride solution in a weight ratio of 2:1, and stirring and mixing are uniformly performed, to obtain a catalyst emulsion;

[0048] The catalyst emulsion is uniformly sprayed on the PTFE fiber substrate, so that 5 grams of catalyst are contained on every 1 kilogram of PTFE fiber, and then sintering is performed at 350 DEG C for 4 hours; after cooling to room temperature, clean washing is performed with deionized water, and after drying, the puffing treatment is completed, and the denitration and dioxin integrated catalytic fiber is obtained.

[0049] Comparative Example 2

[0050] A denitration and dioxin integrated catalytic fiber, and a preparation method thereof, are disclosed.

[0051] S1, Y-type molecular sieve is added to water, and stirring is uniformly performed to form a slurry; then, sodium silicate solution (10 wt% SiO2) in an amount of 1 times the weight of the Y-type molecular sieve is slowly added after heating to 90 DEG C, and stirring and mixing are uniformly performed; then, hydrochloric acid is added to adjust the pH to 6.5, and aging is performed for 1 hour; then, drying is performed, and calcination is performed at 300 DEG C for 3 hours, to obtain molecular sieve coated with a silicon dioxide layer.

[0052] Manganese nitrate, copper nitrate trihydrate and citric acid monohydrate in a weight ratio of 10:4:30 were added to deionized water, stirred at room temperature until the solution was clear and transparent, to obtain a precursor solution; the molecular sieve coated with the silica layer in 4 times the weight of manganese nitrate was immersed in the precursor solution, dried at 90°C for 10 h, and then calcined at 550°C for 3 h to obtain a catalyst;

[0053] S2, the catalyst was crushed and ground to a powder with an average particle size of 150 nm, then the powder was added to a binder composed of 80 wt% methyl acrylate and 5 wt% ammonium chloride solution in a weight ratio of 2:1, stirred and mixed uniformly to obtain a catalyst emulsion;

[0054] The catalyst emulsion was uniformly sprayed on the PTFE fiber substrate so that 5 g of catalyst was contained per 1 kg of PTFE fiber, and then sintered at 350°C for 4 h. After cooling to room temperature, the sample was washed with deionized water and dried to complete the expansion treatment, thereby obtaining the denitration and dioxin integrated catalytic fiber.

[0055] The catalytic fiber obtained in the examples and comparative examples was prepared with ordinary PTFE fiber in a weight ratio of 2:1, and a needle felt filter cloth was made from the ordinary PTFE fiber mesh cloth. A layer of polytetrafluoroethylene dense film was then hot-pressed on the surface of the needle felt filter cloth, and finally the catalytic filter bag was sewn together. The obtained catalytic filter bag was installed in a bag-type dust collector.

[0056] The effect of the bag-type dust collector on the removal of flue dust and organic gaseous pollutants was tested. Flue gas containing nitrogen oxides and dioxins was introduced into the bag-type dust collector. The flue gas contained NO x 400 mg / Nm 3 , NH3 400 mg / Nm 3 , O2 10%, dioxin (chlorobenzene) 3.2 ng I-TEQ / Nm 3 , and carrier gas N2. The flue gas temperature was 200°C. The NO x concentration at the inlet and outlet was determined by a KM9106 (Kane) flue gas analyzer, and the dioxin concentration was determined by high-resolution chromatography and high-resolution mass spectrometry. The test data are shown in Table 1.

[0057] Table 1 Denitration and dioxin removal efficiency of the bag-type dust collector of the examples and comparative examples

[0058]

[0059] NOx removal rate = [(C0-C) / C0] × 100%; wherein C0 is the initial concentration of NO x , and C is the concentration of NO xConcentration; dioxin removal rate = [(X0-X) / X0]x100%; wherein, X0 is initial dioxin concentration, and X is dioxin concentration in the gas after treatment.

[0060] The results in Table 1 can show that, compared to the comparative examples, the catalytic filter bag in the bag filter of the inventive examples has higher catalytic efficiency, and has good catalytic removal effect on nitrogen oxides and dioxins.

[0061] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes to the technical solutions and inventive concepts of the present application within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A denitrification and dioxin removal integrated catalytic fiber, characterized in that, The catalyst is loaded on PTFE fibers. The catalyst is prepared by using a molecular sieve coated with a silica layer as a carrier, a manganese-copper composite oxide as an active catalytic component, and a nickel-cobalt composite oxide as a catalytic component. The molecular sieve coated with a silica layer is prepared by reacting a molecular sieve with an alkali silicate under acidic conditions. The content of manganese oxide is 5-15wt%, the content of copper oxide is 1-7wt%, the content of nickel oxide is 0.5-5wt%, and the content of cobalt oxide is 0.5-3wt%.

2. The denitration and dioxin integrated catalytic fiber according to claim 1, characterized by, The weight of the silica layer is 5-20wt% of the molecular sieve. The molecular sieve is at least one of Y-type molecular sieve, SAPO series molecular sieve, or MCM series molecular sieve.

3. The denitration and dioxin integrated catalytic fiber according to claim 1, characterized by, The preparation method comprises the following steps: S1, adding precursors of manganese, copper, nickel, and cobalt and an acid reagent into water to obtain a precursor solution, then immersing a molecular sieve coated with a silica layer in the precursor solution, drying, and calcining to obtain a catalyst; S2, grinding the catalyst into powder, adding it into a binder to obtain a catalyst emulsion, spraying the catalyst emulsion on PTFE fibers, and then performing expansion treatment to obtain the denitration and dioxin integrated catalytic fiber.

4. The denitration and dioxin integrated catalytic fiber according to claim 3, characterized by In step S1, the precursor of manganese is manganese nitrate or manganese chloride, the precursor of copper is copper nitrate or copper chloride, the precursor of nickel is nickel nitrate, and the precursor of cobalt is cobalt nitrate; and the acid reagent is citric acid.

5. The denitration and dioxin integrated catalytic fiber according to claim 3 or 4, characterized by, In step S1, the drying temperature is 80-100℃, and the time is 5-12h; and the calcination temperature is 500-600℃, and the time is 2-4h.

6. The denitration and dioxin integrated catalytic fiber according to claim 3 or 4, characterized by, In step S2, the binder is a solution comprising methyl acrylate and ammonium chloride.

7. The denitration and dioxin integrated catalytic fiber according to claim 3 or 4, wherein In step S2, the expansion treatment temperature is 300-400℃, and the time is 3-5h.

8. A catalytic filter bag characterized by, The filter bag is sewn from needle-punched felt filter cloth comprising the catalytic fiber of any one of claims 1-7.

9. Use of the catalytic filter bag of claim 8 in flue gas denitration and dioxin removal.

Images