Hydrophilic polypropylene filler for demisting section of packed tower as well as preparation method and application of hydrophilic polypropylene filler
The hydrophilic polypropylene filler prepared by ultraviolet light-induced grafting reaction and blending modification with a hydrophilic agent solves the problems of desulfurization liquid loss and mist entrainment caused by the hydrophobicity of existing fillers, and achieves efficient desulfurization liquid recovery and stable system operation.
Patent Information
- Application Number
- CN202510928295.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-07
- Publication Date
- 2025-10-28
AI Technical Summary
Existing packing materials are hydrophobic, have low water collection efficiency, cause serious mist entrainment, result in large desulfurization liquid losses, and are difficult to meet emission standards. Furthermore, impurities accumulate severely in the packing materials, affecting the operation of the desulfurization system.
Hydrophilic polypropylene fillers were prepared by using ultraviolet light-induced grafting reaction and blending with hydrophilic agents. The polypropylene was grafted with polar monomers through ultraviolet light-induced free radical reaction, and then mixed with hydrophilic agents to form highly hydrophilic fillers. Combined with injection molding process, fillers with superhydrophilicity and antifouling ability were prepared.
It significantly improved the desulfurization liquid recovery rate, reduced mist entrainment, simplified the packing structure, reduced the frequency of component replacement, and ensured the long-term stable operation of the desulfurization system.
Smart Images
Figure CN120842487A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of wet desulfurization packing modification technology, and in particular to a hydrophilic polypropylene packing for the demister section of a packing tower, its preparation method, and its application. Background Technology
[0002] In wet desulfurization processes, the outlet airflow of the desulfurization tower is in a saturated humidity state, with a large number of mist-like water droplets carried by the airflow, and the airflow also carries a lot of impurities, such as elemental sulfur, benzene, naphthalene, tar, sulfate, sulfite, etc. These can usually be separated and recovered using packing materials to achieve gas-liquid separation, so that the airflow meets emission standards and the valuable desulfurization liquid is fully recovered.
[0003] Typically, packing materials should possess characteristics such as high water removal efficiency, low ventilation resistance, economic durability, and ease of installation. Currently, packing materials mainly use PP or modified PP materials. However, these materials are usually hydrophobic, resulting in low efficiency in collecting mist-like water droplets. The secondary entrainment of droplets is quite serious, making it difficult to meet emission standards. Furthermore, impurities accumulate severely in the packing material, increasing the resistance of the desulfurization tower and affecting the operation of the desulfurization system. Summary of the Invention
[0004] The purpose of this invention is to solve the problems of existing packing materials being hydrophobic, having low water collection efficiency, serious mist entrainment, large desulfurization liquid loss, and being unable to meet emission standards and desulfurization liquid recovery requirements. The invention provides a hydrophilic polypropylene packing material for the demisting section of a packed tower, which is hydrophilic or even super-hydrophilic, can significantly improve the desulfurization liquid recovery rate of the packing material, while simplifying the packing material structure, eliminating the need for frequent replacement of parts, and ensuring the long-term stable operation of the desulfurization system.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: A hydrophilic polypropylene packing for the demister section of a packed tower contains a catalyst that decomposes under ultraviolet light to generate free radicals, which then initiate a grafting reaction with a polar monomer and are further modified by blending with a hydrophilic agent; wherein the grafting rate of the polar monomer is 5-10%.
[0006] Further, the catalyst is at least one of benzoin ether, acetophenone derivatives, acylphosphine oxides, benzophenones, and thioxanthones, preferably at least one of benzoin dimethyl ether, 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methylphenylacetone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and acylphosphine oxides.
[0007] Furthermore, the polar monomer is maleic anhydride, maleic anhydride derivatives, methacrylic acid, methacrylic acid derivatives, vinyl acetate, alkenyl sulfonic acid and its derivatives, p-styreneformic acid, p-styreneacetic acid, itaconic acid, oleic acid, arachidic acid and combinations thereof, and their salt-forming forms.
[0008] Furthermore, the hydrophilic agent is one or a combination of more than one of polyvinyl alcohol, azodimethyldisilane, sodium dodecyl sulfonate, polyether block amide, polydiallyl dimethyl ammonium chloride, polyacrylamide-co-diallyl dimethyl ammonium chloride, and sodium poly4-styrene sulfonate.
[0009] Furthermore, the water contact angle of the hydrophilic polypropylene filler is 0~70°.
[0010] To further achieve the objectives of this invention, a method for preparing polypropylene packing for the demister section of a packed tower is also provided, comprising the following steps: (1) Dissolve the catalyst in a solvent and mechanically mix it with polypropylene granules and polar monomers to obtain a mixture; (2) The mixture was placed under ultraviolet light irradiation to induce a grafting reaction to obtain grafted polypropylene; (3) The grafted polypropylene is mixed evenly with the hydrophilic agent, and then the mixture is extruded and granulated to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 180~500rpm / min.
[0011] (4) The hydrophilic filler particles are injection molded at a temperature of 180~230℃ to form the required filler.
[0012] Further, in step (1), the solvent is acetone, ethanol or a mixture of acetone and ethanol. When a mixture of acetone and ethanol is selected as the solvent, the mass percentage concentration of ethanol in the mixture is 20% to 80%, and the mass ratio of the catalyst to the solvent is 1:100 to 1:20.
[0013] Furthermore, in step (1), the mass ratio of polar monomer to polypropylene granules is 1:100 to 10:100.
[0014] Furthermore, in step (2), the ultraviolet light wavelength is 250~420nm, the ultraviolet radiation time is 15~45min, and the radiation distance is 5~25cm.
[0015] Further, in step (3), the weight ratio of grafted polypropylene to hydrophilic agent is 9:1 to 7:3. The preferred mixing method for grafted polypropylene and hydrophilic agent is mechanical mixing, with a stirring speed of 100 to 300 r / min and a stirring time of 1 to 20 min. The mixture is then extruded and granulated to obtain a composite material with high hydrophilicity.
[0016] This invention should also protect the application of the above-mentioned hydrophilic polypropylene packing, or the hydrophilic polypropylene packing prepared according to the above method, in water collection, water saving, or gas-liquid separation in the demisting section of a wet desulfurization tower.
[0017] Compared with the prior art, the advantages of the technical solution of the present invention are as follows: (1) This invention achieves hydrophilic modification of filler polypropylene by initiating grafting reaction with ultraviolet light, and further modifies it by blending with hydrophilic agent, so that the hydrophilicity of the hydrophilic surface is effectively improved and the performance is stable while ensuring that the mechanical properties are not affected. This makes the filler hydrophilic and does not absorb water, thus enhancing the ability to remove water droplets carried by the gas phase. (2) The filler of the present invention has improved antifouling ability while being hydrophilic, which helps to reduce the amount of other impurities such as elemental sulfur, benzene, naphthalene, and tar carried in the gas phase. At the same time, the filler has a simple structure and does not require frequent replacement of parts. (3) This invention combines chemical modification by ultraviolet light grafting and physical modification by melt blending. Chemical modification improves the polarity of the filler polypropylene and improves its compatibility with hydrophilic agents. After physical modification, it can effectively improve the hydrophilicity or even superhydrophilicity of the hydrophilic surface. Combined with the method of injection molding filler sheets, the filler has a high water recovery rate. (4) The method of the present invention is simple and easy to operate. It has obvious advantages in application scenarios such as water collection, water saving or gas-liquid separation in the demisting section of wet desulfurization tower. It has low cost and is easy to carry out large-scale industrial production. Attached Figure Description
[0018] Figure 1 A schematic diagram of a packing structure provided by the present invention; Figure 2 This table shows the test results of the fillers prepared in the embodiments and comparative examples of the present invention. Detailed Implementation Example 1
[0019] To make the present invention clearer, the following description, in conjunction with the accompanying drawings, further illustrates a polypropylene packing for the demister section of a packed tower, its preparation method, and its application. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.
[0020] This embodiment provides a method for preparing hydrophilic polypropylene packing for gas-liquid exchange layers, characterized in that: (1) Disperse 0.1 parts by weight of benzoin dimethyl ether in a mixed solution of 10 parts by weight of acetone and ethanol, wherein the mass percentage concentration of ethanol in the mixed solvent is 40%, and prepare a reaction solution. Put 90 parts by weight of PP granules and 6 parts by weight of maleic anhydride into a mixing container and mechanically mix them evenly. (2) Place the mixture in a UV curing machine for 15 minutes, then place it in a vacuum drying oven at 60~65℃ for 5 hours to dry, and then take it out to obtain grafted polypropylene. (3) 90 parts by mass of grafted polypropylene and 10 parts by mass of polyvinyl alcohol are mixed evenly, and then the mixture is extruded and granulated to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 300rpm / min to obtain hydrophilic polypropylene particles. (4) Hydrophilic polypropylene particles are injection molded at 220°C to form the required filler. Example 2
[0021] This second embodiment provides a method for preparing a hydrophilic polypropylene packing for a gas-liquid exchange layer, characterized in that: (1) Disperse 0.2 parts by mass of 1-hydroxycyclohexylbenzophenone in a mixed solution of 10 parts by mass of acetone and ethanol, wherein the mass percentage concentration of ethanol in the mixed solvent is 30%, and prepare a reaction solution. Put 90 parts by mass of PP granules and 6 parts by mass of methacrylic acid into a mixing container and mechanically mix them evenly. (2) Place the mixture in a UV curing machine for 20 minutes, then place it in a vacuum drying oven at 60~65℃ for 5 hours to dry, and then take it out to obtain grafted polypropylene. (3) Mix 80 parts by mass of grafted polypropylene and 20 parts by mass of polyvinyl alcohol evenly, and then extrude the mixture to granulate to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 300rpm / min to obtain hydrophilic polypropylene particles. (4) The hydrophilic polypropylene particles are injection molded at 230°C to form the required filler. Example 3
[0022] This embodiment three provides a method for preparing a hydrophilic polypropylene packing for a gas-liquid exchange layer, characterized in that: (1) Disperse 0.3 parts by mass of 1-hydroxycyclohexylbenzophenone in a mixed solution of 10 parts by mass of acetone and ethanol, wherein the mass percentage concentration of ethanol in the mixed solvent is 30%, and prepare a reaction solution. Put 90 parts by mass of PP granules and 8 parts by mass of vinyl acetate into a mixing container and mechanically mix them evenly. (2) Place the mixture in a UV curing machine for 35 minutes, then place it in a vacuum drying oven at 60~65℃ for 5 hours to dry, and then take it out to obtain grafted polypropylene. (3) Mix 80 parts by mass of grafted polypropylene with 20 parts by mass of sodium dodecyl sulfonate evenly, and extrude the mixture to granulate to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 300rpm / min to obtain hydrophilic polypropylene particles. (4) The hydrophilic polypropylene particles are injection molded at 230°C to form the required filler. Example 4
[0023] This embodiment four provides a method for preparing a hydrophilic polypropylene packing for a gas-liquid exchange layer, characterized in that: (1) Disperse 0.4 parts by mass of 1-hydroxycyclohexylbenzophenone in a mixed solution of 10 parts by mass of acetone and ethanol, wherein the mass percentage concentration of ethanol in the mixed solvent is 30%, and prepare a reaction solution. Put 90 parts by mass of PP granules and 8 parts by mass of vinyl acetate into a mixing container and mechanically mix them evenly. (2) Place the mixture in a UV curing machine for 35 minutes, then place it in a vacuum drying oven at 60~65℃ for 5 hours to dry, and then take it out to obtain grafted polypropylene. (3) 70 parts by mass of grafted polypropylene and 30 parts by mass of azodimethyldisilane are mixed evenly, and then the mixture is extruded and granulated to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 300rpm / min to obtain hydrophilic polypropylene particles. (4) The hydrophilic polypropylene particles are injection molded at 230°C to form the required filler. Example 5
[0024] This fifth embodiment provides a method for preparing a hydrophilic polypropylene packing for a gas-liquid exchange layer, characterized in that: (1) Disperse 0.5 parts by mass of 1-hydroxycyclohexylbenzophenone in a mixed solution of 10 parts by mass of acetone and ethanol, wherein the mass percentage concentration of ethanol in the mixed solvent is 30%, and prepare a reaction solution. Put 90 parts by mass of PP granules and 9 parts by mass of maleic anhydride into a mixing container and mechanically mix them evenly. (2) Place the mixture in a UV curing machine for 35 minutes, then place it in a vacuum drying oven at 60~65℃ for 5 hours to dry, and then take it out to obtain grafted polypropylene. (3) 70 parts by mass of grafted polypropylene and 30 parts by mass of sodium dodecyl sulfonate are mixed evenly, and then the mixture is extruded and granulated to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 300rpm / min to obtain hydrophilic polypropylene particles. (4) The hydrophilic polypropylene particles are injection molded at 230°C to form the required filler.
[0025] In the above embodiments, the method for determining the grafted side groups on the polypropylene surface is as follows: the content of the main elements of the grafted components on the polypropylene surface is measured using the energy dispersive spectroscopy accessory of the Hitachi S4800 scanning electron microscope; and the content of the grafted material on the polypropylene surface is deduced by inversely using the molecular formula of the grafted material as the surface grafting rate.
[0026] The UV curing machine used in this invention is manufactured by Spectroline, USA, model SB-100P / FA, with a spectral range of 300~400nm and a stable wavelength of 365nm.
[0027] In the above embodiments, the water contact angle parameter was measured using an EASY DROP contact angle tester from KRUSS GmbH, Germany. The measurement range was 1~180°, with a resolution of ±0.1°. The static contact angle measurement mode was used. Each time, a fixed volume of 2µL of water droplet or white oil droplet was dropped onto the porous material. The calculated initial contact angle was taken as the contact angle measurement value of the porous material surface. Six parallel measurements were performed, and the average value was calculated.
[0028] This invention provides a packing structure, such as Figure 1 As shown.
[0029] To verify the above-mentioned filler properties, the present invention also provides a set of comparative examples, as follows: Comparative Example 1: Except for not mixing with a hydrophilic agent and directly extruding and granulating the grafted polypropylene, everything else was the same as in Example 1.
[0030] Comparative Example 2: Except for not mixing with a hydrophilic agent and directly extruding and granulating the grafted polypropylene, everything else was the same as in Example 2.
[0031] Comparative Example 3: Except for not mixing with a hydrophilic agent and directly extruding and granulating the grafted polypropylene, everything else was the same as in Example 3.
[0032] Comparative Example 4: Except for not mixing with a hydrophilic agent and directly extruding and granulating the grafted polypropylene, everything else was the same as in Example 4.
[0033] Comparative Example 5: Except for not mixing with a hydrophilic agent and directly extruding and granulating the grafted polypropylene, everything else was the same as in Example 5.
[0034] Comparative Example 6: Pure polypropylene granules were injection molded at 230°C to form the required filler.
[0035] Test structure as follows Figure 2The table shown illustrates that, based on the data comparison, the polypropylene filler prepared by the method of this invention, after being subjected to ultraviolet light irradiation and then mixed with a hydrophilic agent, exhibits hydrophilicity and even superhydrophilicity compared to pure polypropylene and polypropylene subjected to only ultraviolet light irradiation. This demonstrates that the hydrophilic modification of the polypropylene filler is highly effective, and the resulting filler is suitable for applications in water collection, water conservation, or gas-liquid separation in the demister section of wet desulfurization towers.
[0036] In addition to the embodiments described above, the present invention may have other implementations. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.
Claims
1. A hydrophilic polypropylene packing for the demister section of a packed tower, characterized in that: The hydrophilic polypropylene filler contains a catalyst that decomposes under ultraviolet light to generate free radicals, which then initiate a grafting reaction with polar monomers and are further modified by blending with a hydrophilic agent; wherein the grafting rate of polar monomers is 5~10%.
2. The hydrophilic polypropylene packing for the demisting section of the packed tower according to claim 1, characterized in that: The catalyst is at least one of benzoin ether, acetophenone derivatives, acylphosphine oxides, benzophenones, and thioxanthones, preferably at least one of benzoin dimethyl ether, 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methylphenylacetone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and acylphosphine oxides.
3. The hydrophilic polypropylene packing for the demisting section of the packed tower according to claim 2, characterized in that: The polar monomers are maleic anhydride, maleic anhydride derivatives, methacrylic acid, methacrylic acid derivatives, vinyl acetate, alkenyl sulfonic acid and its derivatives, p-styreneformic acid, p-styreneacetic acid, itaconic acid, oleic acid, arachidic acid and combinations thereof, and their salt-forming forms.
4. The hydrophilic polypropylene packing for the demisting section of the packed tower according to claim 3, characterized in that: The hydrophilic agent is one or a combination of more than one of polyvinyl alcohol, azodimethyldisilane, sodium dodecyl sulfonate, polyether block amide, polydiallyl dimethyl ammonium chloride, polyacrylamide-co-diallyl dimethyl ammonium chloride, and sodium poly4-styrene sulfonate.
5. The hydrophilic polypropylene packing for the demisting section of the packed tower according to claim 4, characterized in that: The water contact angle of the hydrophilic polypropylene filler is 0~70°.
6. A method for preparing polypropylene packing for the demister section of a packed tower as described in claim 5, characterized in that: (1) Dissolve the catalyst in a solvent and mechanically mix it with polypropylene granules and polar monomers to obtain a mixture; (2) The mixture was placed under ultraviolet light irradiation to induce a grafting reaction to obtain grafted polypropylene; (3) The grafted polypropylene is mixed evenly with the hydrophilic agent, and then the mixture is extruded and granulated to obtain a highly hydrophilic composite material. The granulation is carried out by a twin-screw extruder, and the temperature of each section of the twin-screw extruder is 170~250℃, and the screw speed is 180~500rpm / min. (4) The hydrophilic filler particles are injection molded at a temperature of 180~230℃ to form the required filler.
7. The method for preparing the hydrophilic polypropylene packing for the demister section of the packed tower according to claim 6, characterized in that: In step (1), the solvent is acetone, ethanol or a mixture of acetone and ethanol. When a mixture of acetone and ethanol is selected as the solvent, the mass percentage concentration of ethanol in the mixture is 20% to 80%, and the mass ratio of catalyst to solvent is 1:100 to 1:
20.
8. The method for preparing the hydrophilic polypropylene packing for the demister section of the packed tower according to claim 6, characterized in that: In step (1), the mass ratio of polar monomer to polypropylene granules is 1:100 to 10:
100.
9. The method for preparing the hydrophilic polypropylene packing for the demister section of the packed tower according to claim 6, characterized in that: In step (2), the ultraviolet light wavelength is 250~420nm, the ultraviolet radiation time is 15~45min, and the radiation distance is 5~25cm.
10. The method for preparing the hydrophilic polypropylene packing for the demister section of the packed tower according to claim 6, characterized in that: In step (3), the weight ratio of grafted polypropylene to hydrophilic agent is 9:1 to 7:
3. The preferred mixing method for grafted polypropylene and hydrophilic agent is mechanical mixing, with a stirring speed of 100 to 300 r / min and a stirring time of 1 to 20 min. The mixture is then extruded and granulated to obtain a composite material with high hydrophilicity.