KR100673141B1 - Method for producing medium and high temperature filter medium using foam coating and filter medium prepared by this method - Google Patents

Abstract

The present invention relates to a method for producing a medium and high temperature flue gas treatment filter medium having high dust collection efficiency, high heat resistance and durability, high dust layer glass efficiency, and high air permeability, and a filter medium produced by the method. The method for producing a filter medium according to the present invention comprises the steps of preparing a coupling agent for providing a bonding force between the support fabric and the surface layer coating material made of inorganic fiber fabric; Spraying the prepared coupling agent on the surface of the support fabric, and drying the coupling agent at a predetermined temperature for a predetermined time to pretreat the support fabric; Spraying and spraying a foam solution made by mixing a heat-resistant water-soluble resin, a heat-resistant inorganic filler, a foaming agent, a foam stabilizer, a flame retardant, and water with a foam generator to a surface of the pretreated support fabric; And forming a surface layer on the support fabric by flattening the foam liquid applied to the support fabric to a predetermined thickness, and performing a heat treatment for drying and curing the surface layer at a predetermined temperature for a predetermined time, followed by cooling to room temperature.

Description

Method for fabricating filter using foam coating to be used in middle and high temperature atmosphere and filter fabricated by the same}

1 is a flow chart for explaining a method for producing a surface filter medium for treating medium and high temperature exhaust gas using foam coating according to the present invention.

Figure 2 schematically shows a system for performing a method for producing a surface filter medium for treating medium and high temperature exhaust gas using foam coating according to the present invention.

Figure 3 is a photograph taken the size of the foam generated when the foam prepared in accordance with the present invention coated on the support fabric.

4 is a photograph enlarged 500 times the photo of FIG.

(Explanation of symbols for the main parts of the drawing)

1: bubble generator 2: feed pump

3: fiberglass fabric 4: fabric feed roll

5: foam coating processing fabric roll 6: conveyor belt

7: supply pipe 8: blade

9: flat roll 10: drying and curing oven

11: stirrer

The present invention is a method for producing a medium and high temperature flue gas treatment filter medium of 250-300 ℃ range that can maximize the surface filtration effect of the filter medium by forming a microporous surface layer using a foam coating on the inorganic fiber fabric support and It relates to a filter medium produced by this method.

Various dusts generated in the combustion process of industrial boilers, etc. have become a deteriorating factor in the atmospheric environment. The filter dust collecting device frequently used to remove such fine dust has high efficiency and convenience of use, but since a high pressure drop occurs as the dust collection proceeds, an alternative to this has been studied in various angles. During the fine dust filtration, solid particles are continuously accumulated on the filter to form a dust layer, and the formed dust layer forms an additional filtration layer by forming another particle fixing layer. As the filtration progresses to a certain degree, the filtration effect of the dust layer appears rather than the inherent characteristics of the filter.

The dust bed determines the ultimate dust filtration performance and is influenced by the filter's structure, dust properties (size, morphology, particle interactions) and filtration operating conditions (filtration rate, dust concentration, filtration temperature). In particular, the surface structure or pore size of the filter determines the dust layer at the initial stage of filtration, and the initial dust layer affects the subsequent formation of the filtration layer and the filtration mechanism as the filtration progresses. It is the dominant factor in the filtration process.

However, studies on the formation of dust layers are mainly limited to fibrous filters or textile filters and are intermittently performed. Therefore, the inorganic filter for the hot gas purification is made of a special material and a manufacturing method so that deformation or physical property change of the material does not occur even at a high temperature, so there is an obvious structural difference between the fibrous filter or the fabric filter and the inorganic filter for the hot gas purification. Therefore, there is an urgent need for dust layer analysis studies suitable for this.

As a filter applied in the conventional dust collecting process, an internal filtration filter has been commonly used. In the case of such internal filtration filters, since most of the problems such as increase in pressure loss due to the penetration of fine dust particles into the filter, reduction of dust collection efficiency, shortening of filter life, and so on, most of the developed countries are generally porous A surface filtration filter which bonds the surface layer to prevent filter penetration of fine dust particles is used to improve dust collection and dust removal efficiency and to extend the life of the filter cloth.

Currently, a method of manufacturing a porous surface layer mainly used is classified into a coating and a laminating method. Among these methods, as a method of maximizing the porous structure of the filter surface, the coating method has been used a lot because it has the advantage of less technical constraints than the bonding method. Among the coating methods, in the case of foam coating, it is excellent for removing dust by forming a surface layer on the surface of the filter, and in the manufacturing process of the filter, not only is it easy to mass-produce, but also the processing agent is increased by the volume increase due to foam. It is widely distributed on the surface of the filter to facilitate diffusion. In addition, there are advantages such as water saving, waste water generation, processing agent saving, productivity improvement, and the like, and are widely expected in a wide range of applications.

In the coating method, considerations for foam coating include proper fabrication by changing all these factors such as the fabric's structure, composition, weight, pretreatment and properties of the foam itself, ie viscosity, half-life, rupture rate, absorption of bursting foam, etc. You can select the condition. However, foam coating also has a technical problem of saving energy consumed to heat and evaporate water in the drying process after the wet process.

In relation to such foam coating, Korean Patent Application No. 10-1990-0018898 discloses a method of foam coating using a polyurethane resin and a blowing agent in a spinning yarn and knit fabric, and a patent application 10-1999-0015232 No. discloses a method of coating a resin foam obtained by blowing an emulsified liquid by mixing a water-soluble resin, an acrylic thickener, a foaming agent, a foam stabilizer, a surfactant, activated carbon, and the like on the surface of a nonwoven fabric. 2000-0033065 discloses a method of coating in the same manner as described above, but coating only on the yarn portion of the glass fiber. In the case of these methods, the formation of the filter surface layer has an excellent advantage, but it is not applicable to the filter that removes the fine dust in the gaseous medium and high temperature gas of 250 ° C or higher using acrylic resin because of thermal stability problem.

In addition, Korean Patent Application No. 10-1996-0064732 discloses a technique of foam coating water-soluble resin on natural fibers and Patent Application No. 10-1998-039696 discloses a technique of foam coating water-soluble resin on polyethylene fibers, the use of these techniques Was intended to use as a non-woven wallpaper.

In Korean Patent Application Nos. 10-2003-0087531 and 10-2003-0087533, a filter having a multi-layer porosity is manufactured by mixing ceramic powders such as silicon carbide and alumina and a binder and applying them to a filter base. The method is disclosed. Although this method can secure thermal stability, the energy consumption is increased according to the elevated temperature of 900 ~ 1,300 ℃ during the sintering process, and has a disadvantage of lower dust removal efficiency than foam coating.

Korean Patent Application No. 10-2000-0055084 also discloses a method of manufacturing a multilayer ceramic fiber filter, but it has a disadvantage in that it has no flexibility and low dust removal efficiency because it is a pad type.

Therefore, the object of the present invention can solve all the problems of the prior art as described above, while the dust collection efficiency is high, heat resistance and durability, dust layer glass efficiency improvement and air permeability for the treatment of medium and high temperature flue gas It is to provide a method for producing a filter medium and a filter medium produced by the method.

The above object is to prepare a coupling agent for providing a bonding force between the support fabric and the surface layer coating material made of inorganic fiber fabric; Spraying the prepared coupling agent on the surface of the support fabric, and drying the coupling agent at a predetermined temperature for a predetermined time to pretreat the support fabric; Spraying and spraying a foam solution made by mixing a heat-resistant water-soluble resin, a heat-resistant inorganic filler, a foaming agent, a foam stabilizer, a flame retardant, and water with a bubble generator to a surface of the pretreated support fabric; And forming a surface layer on the support fabric by flattening the foam liquid applied to the support fabric to a predetermined thickness, and performing a heat treatment for drying and curing the surface layer at a predetermined temperature for a predetermined time, followed by cooling to room temperature. It can be achieved by the medium and high temperature filter medium manufacturing method using a foam coating according to an embodiment of the present invention.

In the above coupling agent, a) a solution obtained by dispersing and dissolving a solution of 2 to 10 parts by weight of an organosilane or a partial condensate thereof and 10 to 50 parts by weight of a lower alcohol for 0.5 to 1.5 hours at a temperature of 0 to 25 ° C and agitation. Making; b) making a solution of 2 to 10 parts by weight of deionized water, 10 to 50 parts by weight of lower alcohol and 0.05 to 1 part by weight of organic or inorganic acid; c) the solution of step b) is added to the solution prepared in step a) and reacted under stirring for 1 to 3 hours.

The heat-resistant water-soluble resin is a heat-resistant water-soluble resin that is a polytetrafluoroethylene (PTFE) resin, a silicone resin or a mixture thereof.

The heat-resistant inorganic filler includes aluminum hydroxide, silicon oxide, aluminum oxide, carbon, ferrite.

The blowing agent is an anion-based or nonion-based blowing agent including a polyethylene glycol type or a polyhydric alcohol type including sodium larurate and sodium stearate.

The foam stabilizer is hydroethyl cellulose or carboxymethyl cellulose.

The flame retardant is a phosphorus flame retardant.

The dispersion is composed of 45 to 75 parts by weight of heat-resistant water-soluble resin, 20 to 60 parts by weight of heat-resistant inorganic filler, 0.5 to 4.5 parts by weight of foaming agent, 0.1 to 2.0 parts by weight of foam stabilizer, 5 to 15 parts by weight of flame retardant, and 30 to 45 parts by weight of water. .

The bubbler quantitatively supplies air to the dispersion at a rate of 3 L / min, while rotating at a rate of 200 to 250 rpm to produce bubbles.

The support fabric is preferably conveyed at a speed of 3 to 3.5 m / min.

The surface layer is flattened to a thickness of 0.5 to 1.0 mm by a blade and a pair of flat rolls.

The heat treatment of the surface layer is performed by maintaining the isothermal process at this temperature for 10 minutes when the temperature is raised from room temperature to about 8 to 10 ° C./min and reaches a temperature of 150 to 180 ° C.

The above object can also be achieved by a medium- and high-temperature filter medium, which is produced by the above method, according to another aspect of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

1 is a flow chart for explaining a method for producing a surface filter medium for treating medium and high temperature exhaust gas using foam coating according to the present invention. As shown in Figure 1, the method for producing a medium and high temperature flue gas treatment filter body according to the present invention is composed of five steps.

First, a coupling agent capable of exhibiting excellent binding strength between the filter support, which is an inorganic fiber fabric, and the surface layer coating material is prepared. As the fabric used as the filter support, commercially available glass fibers are used. The coupling agent is used for the purpose of bonding the surface layer coating material to the glass fiber of the inorganic fiber fabric with excellent bonding force. The coupling agent may be prepared by the following procedure. a) 2 to 10 parts by weight of an organosilane or its partial condensate and 10 to 50 parts by weight of lower alcohol having a carbon number of 5 or less such as methanol, ethanol, propanol, etc., dispersed and dissolved for 0.5 to 1.5 hours at a temperature of 0 to 25 ° C and stirring To make a solution. b) 2 to 10 parts by weight of deionized water, 10 to 50 parts by weight of lower alcohol and 0.05-1 part by weight of organic or inorganic acid are prepared. c) The solution of step b) is added dropwise to the solution prepared in step a) and reacted under stirring for 1 to 3 hours. The coupling agent thus prepared is sprayed onto the surface of the glass fiber as a surface pretreatment of the fabric, and the coupling agent sprayed on the surface of the glass fiber is dried at 150 ° C. for 5 minutes.

After the surface of the fabric by the coupling agent is treated, a foam coating process on the fabric is performed. In the foam generation step, which is the previous step of the foam coating, a heat-resistant inorganic filler such as aluminum hydroxide, silicon oxide, aluminum oxide, carbon, ferrite, or the like in a heat-resistant water-soluble resin such as polytetrafluoroethylene (PTFE) resin, silicone resin, or a mixture thereof. After the dispersion is made by mixing an anion-based or nonion-based blowing agent such as polyethylene glycol or polyalcohol, foam stabilizer such as hydroethyl cellulose or carboxymethyl cellulose, phosphorus-based flame retardant and water , Bubbles are generated through the bubble generator.

Here, 45 to 75 parts by weight of heat-resistant water-soluble resin, 20 to 60 parts by weight of heat resistant inorganic filler, 0.5 to 4.5 parts by weight of foaming agent, 0.1 to 2.0 parts by weight of foam stabilizer, 5 to 15 parts by weight of flame retardant, and 30 to 45 parts by weight of water. Most preferred. The bubbler feeds air into the dispersion quantitatively at a rate of 3 L / min, while rotating at a rate of 200 to 250 rpm to produce bubbles.

In order to coat the obtained foam on a glass fiber fabric, a coating roll contact as shown in FIG. 2 is carried out. As shown in Fig. 2, in the bubbler 1, the foam liquid is made by the rotation of the stirrer 11 which rotates the dispersion as described above at the rotational speed as described above. The foam liquid is supplied to the fiberglass fabric 3 by the feed pump 2. The glass fiber fabric (3) is transferred from the fabric feed roll (4) to the foam coating fabric roll (5) at a constant speed, and the foam coating is that the fiberglass fabric (3) is foam coated fabric from the fabric feed roll (4). It is carried out while being transferred to the roll (5). When the fiberglass fabric 3 is fed from the fabric feed roll 4 to the foam coated fabric roll 5, the fiberglass fabric 3 is interposed between the fabric feed roll 4 and the foam coated fabric roll 5 When the fiberglass fabric 3 passes through the conveyor belt 6 and the fiberglass fabric 3 passes through the conveyor belt 6, the foam liquid produced in the bubble generator 1 is fed to the supply pipe (2) by the feed pump (2). 7) is fed onto the fiberglass fabric 3.

On the other hand, a blade 8 in the form of a knife is installed on the conveyor belt 6, and the foam liquid supplied over the fiberglass fabric 3 is formed by the blade 8 while the fiberglass fabric 3 passes under the blade 8. In a state of being maintained at a constant thickness by means of), it is adjusted to 0.5 to 1.0 mm while passing between a pair of flat rolls 9 provided adjacent to the conveyor belt 6. At this time, the conveyance speed of the glass fiber fabric 3 is preferably maintained at 3 to 3.5m / min by the rotational speed of the foam coating fabric roll (5).

As described above, the glass fiber fabric 3 (filter body) having completed the foam coating is a drying and curing oven 10 disposed adjacent to the flat roll 9 for drying and heat treatment of the foam liquid applied on the surface. Is committed. The drying and curing oven 10 is raised from room temperature to about 8 to 10 ° C./min, and when it reaches a temperature of 150 to 180 ° C., the isothermal process at this temperature is maintained for 10 minutes. After the drying and heat treatment of the foam liquid applied on the glass fiber fabric 3 as described above is completed, the surface layer forming filter body is completed by undergoing a room temperature cooling process.

Experimental Example 1

In order to analyze the dust collection efficiency of the surface layer-forming filter obtained through the present invention was carried out the following experiment. The filter medium of the present invention is to collect dust contained in the combustion gas of the heavy oil boiler, and the experimental conditions were also simulated by simulating the characteristics of the combustion gas of the heavy oil boiler. For this experiment, first, the temperature of the gas was set to 250 ± 10 ℃, the fine dust that is characteristic of heavy oil boiler, the average particle size of the fine dust is larger than 20㎛, particle diameter of 5-20㎛, and 5-1 The experiment was divided into particle diameters of 1 μm and particle diameters of 1 μm or less.

Characteristics and Dust Collection Efficiency of Dust Dust particle size (㎛) Distribution ratio (%) Dust collection efficiency (%) ≥20 42.8 99.97 5-20 36.4 99.76 1-5 12.5 99.34 ≤1 8.3 99.08

As shown in the table above, dust collection efficiency of more than 99% was obtained at all particle sizes. The larger the particle size, the higher the dust collection efficiency, and the smaller the particle diameter, the more characteristic the characteristics of the typical dust collection filter were obtained.

Experimental Example 2

In order to confirm the physical characteristics of the surface-layered filter medium obtained through the present invention, the following experiment was carried out. Figure 3 is taken with a high-speed camera the shape of the foam generated during the foam coating. It was confirmed that bubbles having a size of 40 μm or less were mainly coated on the surface of the filter medium. 4 is a 500 times magnification of the surface layer forming surface. It was confirmed that the pores formed through the foam coating on the surface is distributed.

As described above, according to the filter medium produced according to the present invention, by applying a microporous material to the surface of the fibrous filter support to dry and heat-treat, it prevents the infiltration of dust particles into the filter medium due to surface filtration In addition, the pressure loss of the filter medium is kept low, so that the dust removal interval is extended, and the dust collection efficiency can be greatly increased.

In addition, according to the filter medium prepared according to the present invention, the problem that the surface filtration characteristics easily disappear due to the wear and loss of the surface layer of the filter medium in the case of dust particles having a high wear resistance, while solving the fibrous filter medium for dust collection It is a microporous surface layer forming technology excellent in abrasion resistance, chemical resistance, heat resistance and flexibility, and its filter body.

Claims (13)

Preparing a coupling agent for providing a bonding force between the support fabric made of the inorganic fiber fabric and the surface layer coating material; Spraying the prepared coupling agent on the surface of the support fabric, and drying the coupling agent at a predetermined temperature for a predetermined time to pretreat the support fabric; Spraying and spraying a foam solution made by mixing a heat-resistant water-soluble resin, a heat-resistant inorganic filler, a foaming agent, a foam stabilizer, a flame retardant, and water with a foam generator to a surface of the pretreated support fabric; And Forming a surface layer on the support fabric by flattening the foam liquid applied to the support fabric to a predetermined thickness, and performing a heat treatment to dry and cure the surface layer at a predetermined temperature for a predetermined time, followed by cooling to room temperature. A medium and high temperature filter medium production method using a foam coating. The method of claim 1, wherein the coupling agent, a) preparing a solution in which 2 to 10 parts by weight of an organosilane or a partial condensate thereof and 10 to 50 parts by weight of lower alcohol are dispersed and dissolved for 0.5 to 1.5 hours at a temperature of 0 to 25 ° C. and stirring; b) making a solution of 2 to 10 parts by weight of deionized water, 10 to 50 parts by weight of lower alcohol and 0.05 to 1 part by weight of organic or inorganic acid; c) Method for producing a medium and high temperature filter medium using a foam coating, characterized in that the solution of step b) is added to the solution prepared in step a) and reacted under stirring for 1 to 3 hours. The method of claim 1, wherein the heat-resistant water-soluble resin is a heat-resistant water-soluble resin that is a polytetrafluoroethylene (PTFE) resin, a silicone resin or a mixture thereof. The method of claim 1, wherein the heat-resistant inorganic filler comprises aluminum hydroxide, silicon oxide, aluminum oxide, carbon, ferrite. [Claim 2] The medium and high temperature filtration using foam coating according to claim 1, wherein the blowing agent is an anion-based or nonion-based blowing agent including a polyethylene glycol type or a polyhydric alcohol type including sodium larurate and sodium stearate. Sieve manufacturing method. The method of claim 1, wherein the foam stabilizer is hydroethyl cellulose or carboxymethyl cellulose. The method of claim 1, wherein the flame retardant is a phosphorus-based flame retardant. According to claim 1, wherein the dispersion is 45 to 75 parts by weight of heat-resistant water-soluble resin, 20 to 60 parts by weight of heat-resistant inorganic filler, 0.5 to 4.5 parts by weight of foaming agent, 0.1 to 2.0 parts by weight of foam stabilizer, 5 to 15 parts by weight of flame retardant and water Method for producing a medium and high temperature filter medium using a foam coating, characterized in that consisting of 30 to 45 parts by weight. According to claim 1, wherein the bubble generator for supplying air to the dispersion in a quantitative air at a rate of 3L / min, while rotating at a speed of 200 to 250rpm to produce foam for medium and high temperature using a foam coating Method for producing filter medium. The method of claim 1, wherein the support fabric is conveyed at a speed of 3 to 3.5m / min method for producing medium and high temperature filter medium using a foam coating. The method of claim 1, wherein the surface layer is flattened to a thickness of 0.5 to 1.0 mm by a blade and a pair of flat rolls. The method of claim 1, wherein the heat treatment of the surface layer is carried out by maintaining the isothermal process at this temperature for 10 minutes when the temperature is raised from room temperature to about 8 to 10 ℃ / min, reaching a temperature of 150 to 180 ℃ Method for producing medium and high temperature filter medium using a foam coating, characterized in that. A medium and high temperature filter medium produced by the method according to any one of claims 1 to 12.

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