Preparation method of polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitration filter material

Abstract

The application discloses a preparation method of a polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitration filter material, and belongs to the field of industrial flue gas purification. X The method solves the problems of long-term erosion of existing filter materials, industrialization difficulty, high cost and the like. The method uses polytetrafluoroethylene emulsion as a main material of a coating agent, adds a V2O5-WO3 / TiO2 catalyst modified by a KH550 silane coupling agent, an anti-sulfur agent ammonium molybdate, an anti-sulfur synergist CeO2, a nano MnO2-graphene composite demercuration agent and betaine into the coating agent, prepares a PTFE foamed coating agent, uniformly coats the PTFE foamed coating agent on the surface of polyphenylene sulfide needle-punched felt, and forms a dust removal and denitration integrated filter material after drying treatment. The filter material prepared by the method has high dust removal efficiency and denitration efficiency, and has a good application prospect in the field of industrial flue gas purification.

Description

Technical Field

[0001] This invention belongs to the field of industrial flue gas purification, specifically relating to a method for preparing a polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitrification filter material. Background Technology

[0002] Industrial waste gases from steelmaking, cement production, and waste incineration often contain large amounts of pollutants such as nitrogen oxides, dust, and sulfur oxides. X Dust is one of the major air pollutants, which not only harms human health but also causes serious environmental problems such as acid rain, photochemical smog, and the greenhouse effect. Therefore, in the treatment of industrial flue gas, efficient dust removal and deep denitrification are not only basic requirements for industrial enterprises to meet environmental emission standards, but also key means to protect public health and improve the ecological environment, playing an irreplaceable role in promoting green industrial development.

[0003] Currently, dust removal in various industries mainly relies on electrostatic precipitators, bag filters, or hybrid electrostatic-bag filters. Among these, bag filters are the mainstream technology due to their high collection efficiency. Denitrification primarily uses reducing agents to convert the gas into nitrogen, mainly employing selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) technologies. However, in practical applications, both SNCR and SCR technologies have certain limitations. The core limitations of SNCR are its low efficiency, reliance on high temperatures, and susceptibility to ammonia escape, making it suitable for scenarios with lower denitrification requirements and stable flue gas temperatures. While SCR offers high efficiency, it is limited by catalyst cost, temperature window, and system complexity, making it more suitable for industries with stringent denitrification requirements but able to afford higher costs. It is evident that the separate application of existing dust removal and denitrification technologies faces bottlenecks in terms of efficiency, cost, and adaptability. Developing a composite filter material that integrates high-efficiency dust removal and deep denitrification functions can leverage the high-efficiency capture advantages of bag filters while overcoming the limitations of traditional denitrification technologies, thereby achieving synergistic treatment of pollutants. This is of vital practical significance for reducing system complexity, saving costs, and improving the comprehensive treatment efficiency of industrial flue gas.

[0004] In the field of integrated dust removal and denitrification filter media, Chinese patent CN 119215552 A proposes a PTFE foam-coated multifunctional dust removal and denitrification filter media and its preparation method. This involves preparing a high-efficiency denitrification catalyst and a needle-punched felt with a double-base fabric as the substrate. The catalyst powder is then uniformly impregnated onto the needle-punched felt and dried. Subsequently, a PTFE foam coating is applied to the surface of the needle-punched felt, ultimately producing the multifunctional dust removal and denitrification filter media. While this method offers innovation in integrating dust removal and denitrification functions, analysis of technical details and industrial application scenarios reveals the continued presence of SO₂ in industrial flue gas. XThis leads to catalyst poisoning. Chinese patent CN 113476958 A addresses this by immersing the filter media substrate in a metal salt solution, then spraying urea or ammonia solution onto the surface, followed by hydrogen peroxide solution, and finally heat treatment to obtain an integrated denitrification and dust removal filter media. While this patented integrated denitrification and dust removal filter media offers advantages in catalyst bonding strength, uniform distribution, and permeability, it still faces challenges in industrial production, including high costs and difficulties. Therefore, although current integrated dust removal and denitrification filter media have made some progress in functional integration and structural optimization, they still face key common problems. On the one hand, the catalyst's resistance to poisoning is insufficient, making it difficult to tolerate SO₂ in industrial flue gas. X Long-term erosion by corrosive components limits the service life of filter media. On the other hand, although some technologies perform well in terms of catalyst bonding strength and air permeability, they are limited by complex preparation processes, resulting in difficulties in industrial production and high costs. These shortcomings together restrict the large-scale promotion and application of integrated dust removal and denitrification filter media in industrial flue gas treatment. Summary of the Invention

[0005] This invention addresses the problems of insufficient anti-poisoning ability, high difficulty in industrial production, and high cost of integrated dust removal and denitrification filter media in industrial applications. It provides a preparation process for polyphenylene sulfide-based polytetrafluoroethylene (PTFE) foam-coated denitrification filter media. This process uses PTFE emulsion as the main material of the coating agent, adding KH550 silane coupling agent-modified V2O5-WO3 / TiO2 catalyst powder, ammonium molybdate as an antisulfur agent, CeO2 as an antisulfur synergist, nano-MnO2-graphene composite mercury removal agent, and betaine as a foaming agent to formulate a stable PTFE foam coating agent. The PTFE foam coating agent is then uniformly coated onto the surface of polyphenylene sulfide (PPS) needle-punched felt, and after drying, an integrated dust removal and denitrification filter material is formed. The specific preparation method includes the following steps:

[0006] (1) Add the V2O5-WO3 / TiO2 catalyst modified with KH550 silane coupling agent to deionized water and disperse it by ultrasonication to prepare V2O5-WO3 / TiO2 dispersion.

[0007] (2) Add appropriate amounts of anti-sulfur agent ammonium molybdate, anti-sulfur synergist CeO2 powder and nano MnO2-graphene composite mercury removal agent to the V2O5-WO3 / TiO2 dispersion in (1), and form an integrated functional slurry after thorough stirring.

[0008] (3) Take an appropriate amount of PTFE emulsion with a solid content of 50%-60%, add it to the integrated functional slurry in (2), stir thoroughly, add a certain amount of foaming agent betaine, and continue stirring for 20-30 minutes to obtain PTFE foam coating agent.

[0009] (4) Fix the PPS needle-punched felt on the worktable of the coating machine and apply the PTFE foam coating agent evenly by scraping with a scraper.

[0010] (5) Place the coated filter material in an oven at 95℃-105℃ to dry it, forming a porous structure. Then, directly heat it to 150℃-160℃ and keep it at that temperature for 12-15 minutes before taking it out.

[0011] Preferably, the mass fraction of the V2O5-WO3 / TiO2 dispersion in step (1) is 6%-8%.

[0012] Preferably, the integrated functional slurry in step (2) contains 1%-3% ammonium molybdate as an antisulfur agent, 0.5%-1% CeO2 powder as an antisulfur synergist, and 1%-3% nano-MnO2-graphene composite mercury removal agent.

[0013] Preferably, in step (3), the PTFE foam coating agent contains 28%-36% PTFE emulsion and 1%-3% betaine as a foaming agent.

[0014] Preferably, the coating amount in step (4) is controlled at 90-110 g / m².

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The V2O5-WO3 / TiO2 catalyst was modified with KH550 silane coupling agent to improve its compatibility with PTFE emulsion, avoid the activity decay caused by catalyst agglomeration, and ensure the stable catalytic performance of the filter media during long-term operation.

[0017] By adding the antisulfur agent ammonium molybdate and the antisulfur synergist CeO2, ammonium molybdate can directly inhibit the reaction of SO2 and H2O in industrial flue gas to form sulfate, thus preventing sulfate from covering the active sites of V2O5-WO3 / TiO2 catalyst. CeO2 further reduces the strong adsorption of SO2 on the catalyst surface through lattice oxygen cycling, thus preventing catalyst poisoning through a dual pathway of "physical barrier + chemical inhibition".

[0018] The PTFE foam coating is foamed at 95℃ to form a porous structure. Combined with the trapping performance of the PPS needle-punched felt substrate, the filtration efficiency of 2.5μm particles is stable at 99.91%-99.98%. At the same time, by adjusting the amount of catalyst added, the catalytic denitrification efficiency can reach 80.31%-90.74%, which is suitable for the denitrification needs of industries such as steel and waste incineration, and there is no risk of ammonia escape as with SNCR technology. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the filter media structure. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions of this invention, the specific implementation of this invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the implementation of this invention is not limited thereto.

[0021] Example 1

[0022] The specific preparation method includes the following steps:

[0023] (1) Dissolve the V2O5-WO3 / TiO2 catalyst modified with KH550 silane coupling agent in deionized water and ultrasonically disperse for 25 min to prepare V2O5-WO3 / TiO2 dispersion.

[0024] (2) Add appropriate amounts of anti-sulfur agent ammonium molybdate, anti-sulfur synergist CeO2 powder and nano MnO2-graphene composite mercury removal agent to the V2O5-WO3 / TiO2 dispersion in (1), and stir at 50°C for 25 min to form an integrated functional slurry.

[0025] (3) Take an appropriate amount of PTFE emulsion with a solid content of 60%, add it to the integrated functional slurry in (2), stir for 30 minutes, then add a certain amount of foaming agent betaine, and continue stirring for 20 minutes to obtain PTFE foam coating agent.

[0026] (4) Fix the PPS needle-punched felt on the worktable of the coating machine and apply the PTFE foam coating agent evenly by scraping with a scraper.

[0027] (5) Place the coated filter material in a 95°C oven for 4 minutes to form a porous structure, then directly heat it to 160°C and keep it warm for 12 minutes.

[0028] Preferably, the mass fraction of the V2O5-WO3 / TiO2 dispersion in step (1) is 6%.

[0029] Preferably, the integrated functional slurry in step (2) contains 1% ammonium molybdate as an antisulfur agent, 0.5% CeO2 powder as an antisulfur synergist, and 1% nano-MnO2-graphene composite mercury removal agent.

[0030] Preferably, in step (3), the PTFE foam coating agent contains 36% PTFE emulsion and 1% betaine as a foaming agent.

[0031] Preferably, the coating amount in step (4) is controlled at 90 g / m².

[0032] Example 2

[0033] The specific preparation method includes the following steps:

[0034] (1) Dissolve the V2O5-WO3 / TiO2 catalyst modified with KH550 silane coupling agent in deionized water and ultrasonically disperse for 25 min to prepare V2O5-WO3 / TiO2 dispersion.

[0035] (2) Add appropriate amounts of anti-sulfur agent ammonium molybdate, anti-sulfur synergist CeO2 powder and nano MnO2-graphene composite mercury removal agent to the V2O5-WO3 / TiO2 dispersion in (1), and stir at 50°C for 25 min to form an integrated functional slurry.

[0036] (3) Take an appropriate amount of PTFE emulsion with a solid content of 50%, add it to the integrated functional slurry in (2), stir for 30 minutes, then add a certain amount of foaming agent betaine, and continue stirring for 25 minutes to obtain PTFE foam coating agent.

[0037] (4) Fix the PPS needle-punched felt on the worktable of the coating machine and apply the PTFE foam coating agent evenly by scraping with a scraper.

[0038] (5) Place the coated filter material in a 105℃ oven for 4 minutes to form a porous structure, then directly heat it to 150℃ and keep it warm for 15 minutes.

[0039] Preferably, the mass fraction of the V2O5-WO3 / TiO2 dispersion in step (1) is 7%.

[0040] Preferably, the integrated functional slurry in step (2) contains 2% ammonium molybdate as an antisulfur agent, 0.75% CeO2 powder as an antisulfur synergist, and 2% nano-MnO2-graphene composite mercury removal agent.

[0041] Preferably, in step (3), the PTFE foam coating agent contains 32% PTFE emulsion and 2% betaine as a foaming agent.

[0042] Preferably, the coating amount in step (4) is controlled at 100g / m².

[0043] Example 3

[0044] The specific preparation method includes the following steps:

[0045] (1) Dissolve the V2O5-WO3 / TiO2 catalyst modified with KH550 silane coupling agent in deionized water and ultrasonically disperse for 25 min to prepare V2O5-WO3 / TiO2 dispersion.

[0046] (2) Add appropriate amounts of anti-sulfur agent ammonium molybdate, anti-sulfur synergist CeO2 powder and nano MnO2-graphene composite mercury removal agent to the V2O5-WO3 / TiO2 dispersion in (1), and stir at 50°C for 25 min to form an integrated functional slurry.

[0047] (3) Take an appropriate amount of PTFE emulsion with a solid content of 60%, add it to the integrated functional slurry in (2), stir for 30 minutes, then add a certain amount of foaming agent betaine, and continue stirring for 30 minutes to obtain PTFE foam coating agent.

[0048] (4) Fix the PPS needle-punched felt on the worktable of the coating machine and apply the PTFE foam coating agent evenly by scraping with a scraper.

[0049] (5) Place the coated filter material in a 95°C oven for 4 minutes to form a porous structure, then directly heat it to 160°C and keep it warm for 13 minutes.

[0050] Preferably, the mass fraction of the V2O5-WO3 / TiO2 dispersion in step (1) is 8%.

[0051] Preferably, the integrated functional slurry in step (2) contains 3% ammonium molybdate as an antisulfur agent, 1% CeO2 powder as an antisulfur synergist, and 3% nano-MnO2-graphene composite mercury removal agent.

[0052] Preferably, in step (3), the PTFE foam coating agent contains 28% PTFE emulsion and 3% betaine as a foaming agent.

[0053] Preferably, the coating amount in step (4) is controlled at 110 g / m².

[0054] Example 3

[0055] The specific preparation method includes the following steps:

[0056] (1) Dissolve the V2O5-WO3 / TiO2 catalyst modified with KH550 silane coupling agent in deionized water and ultrasonically disperse for 25 min to prepare V2O5-WO3 / TiO2 dispersion.

[0057] (2) Add appropriate amounts of anti-sulfur agent ammonium molybdate, anti-sulfur synergist CeO2 powder and nano MnO2-graphene composite mercury removal agent to the V2O5-WO3 / TiO2 dispersion in (1), and stir at 50°C for 25 min to form an integrated functional slurry.

[0058] (3) Take an appropriate amount of PTFE emulsion with a solid content of 60%, add it to the integrated functional slurry in (2), stir for 30 minutes, then add a certain amount of foaming agent betaine, and continue stirring for 20 minutes to obtain PTFE foam coating agent.

[0059] (4) Fix the PPS needle-punched felt on the worktable of the coating machine and apply the PTFE foam coating agent evenly by scraping with a scraper.

[0060] (5) Place the coated filter material in a 100°C oven for 4 minutes to form a porous structure, then directly heat it to 155°C and keep it warm for 12 minutes.

[0061] Preferably, the mass fraction of the V2O5-WO3 / TiO2 dispersion in step (1) is 7%.

[0062] Preferably, the integrated functional slurry in step (2) contains 1% ammonium molybdate as an antisulfur agent, 0.5% CeO2 powder as an antisulfur synergist, and 1% nano-MnO2-graphene composite mercury removal agent.

[0063] Preferably, in step (3), the PTFE foam coating agent contains 30% PTFE emulsion and 1% betaine as a foaming agent.

[0064] Preferably, the coating amount in step (4) is controlled at 105 g / m².

[0065] The filter material prepared by the above method was used to make four samples. The test data of their 2.5µm particle filtration efficiency, catalytic denitrification efficiency and pressure drop are shown in Table 1.

[0066] Table 1

[0067]

[0068] Although the present invention has been described in detail by way of preferred embodiments, the present invention is not limited thereto. Those skilled in the art can make various specific changes according to different practical needs without departing from the scope and spirit of the present invention, but such changes still fall within the scope of protection of this application.

Claims

1. A method for preparing a polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitration filter material, characterized in that, The method comprises the following steps: S1, adding the V2O5-WO3 / TiO2 catalyst modified by the silane coupling agent KH550 into deionized water and performing ultrasonic dispersion to prepare a V2O5-WO3 / TiO2 dispersion liquid; S2, adding appropriate amounts of the anti-sulfur agent ammonium molybdate, the anti-sulfur synergist CeO2 powder and the nano MnO2-graphene composite mercury removal agent into the V2O5-WO3 / TiO2 dispersion liquid in S1, and forming an integrated functional slurry after sufficient stirring; S3, taking appropriate amounts of PTFE emulsion with a solid content of 50%-60%, adding the integrated functional slurry in S2, adding a certain amount of foaming agent betaine after sufficient stirring, and continuously stirring for 20-30 min to obtain a PTFE foam coating agent; S4, fixing the PPS needle felt on the workbench of a coating machine and uniformly coating the PTFE foam coating agent by a doctor blade; S5, placing the coated filter material into a 95℃-105℃ oven for drying, forming a porous structure, directly heating to 150℃-160℃, and taking out after holding for 12-15 min.

2. The method for preparing polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitrification filter material according to claim 1, characterized in that, The mass fraction of the V2O5-WO3 / TiO2 dispersion liquid in S1 is 6%-8%.

3. The method for preparing polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitrification filter material according to claim 1, characterized in that, The integrated functional slurry in S2 contains 1%-3% of the anti-sulfur agent ammonium molybdate, 0.5%-1% of the anti-sulfur synergist CeO2 powder and 1%-3% of the nano MnO2-graphene composite mercury removal agent.

4. The method for preparing polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitrification filter material according to claim 1, characterized in that, The PTFE foam coating agent in S3 contains 28%-36% of the PTFE emulsion and 1%-3% of the foaming agent betaine.

5. The method for preparing polyphenylene sulfide-based polytetrafluoroethylene foamed coating denitrification filter material according to claim 1, characterized in that, The coating amount in S4 is controlled to be 90-110 g / m².

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