Filtration device

Abstract

To provide a filtration device capable of effectively separating a coloring component from liquid containing the coloring component such as a pigment or a dye.SOLUTION: A filtration device includes a filter part and an inorganic layer provided in the filter part. The inorganic layer includes: first silica having a permeability of equal or greater than 1D and equal to or less than 5D; and second silica having a permeability of equal to or greater than 0.05D and equal to or less than 0.5D.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a filtering device, and more particularly to a filtering device capable of effectively separating dyes, pigments, and the like. [Background technology]

[0002] For example, JP 2015-502246 A describes a filtration device using a microporous material containing a silica filler. Such filtration devices using silica are well known. However, even when silica is used, it is not easy to effectively separate color components, particularly pigments and dyes, from a liquid containing such color components. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2015-502246 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an effective filtration device using a simple method, and in particular, to provide a filtration device that can effectively separate color components such as pigments and dyes from a liquid containing such color components. [Means for solving the problem]

[0005] This invention is based on the finding from examples that dyes can be effectively adsorbed by providing an inorganic layer on a filter in which a plurality of types of silica with different transmittances are mixed.

[0006] A first invention relates to a filtration device, which includes a filter unit and an inorganic layer provided in the filter unit. The inorganic layer contains a first silica having a transmittance of 1D or more and 5D or less, and a second silica having a transmittance of 0.05D or more and 0.5D or less.

[0007] In a preferred example of the filtration device, the first silica is fused calcined silica and the second silica is calcined silica, and the permeability of the first silica may be 1.5D or more and 3D or less, and the permeability of the second silica may be 0.1D or more and 0.4D or less.

[0008] A preferred example of the filtration device further includes a temperature adjusting unit for adjusting the temperature of the raw liquid to be filtered.

[0009] The second invention relates to a filtration method including a step of filtering a solution containing a dye or pigment using the filtration device of the first invention. This method is preferably used when the solution further contains styrene or a styrene-containing polymer in addition to the dye or pigment. This method preferably includes a step of filtering using the filtration device while maintaining the temperature of the solution between room temperature and 100°C using a temperature control unit. [Effects of the Invention]

[0010] According to the present invention, an effective filtration device can be provided by a simple method. In particular, the present invention can provide a filtering device that can effectively separate color components such as pigments and dyes from a liquid containing such color components. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of a rotary drum type precoat filter. [Figure 2] Figure 2 shows an example of the basic flow of filtration using a rotary drum filter. [Figure 3] FIG. 3 is a photograph, instead of a drawing, showing the filtrate of Example 1. [Figure 4] FIG. 4 is a photograph, instead of a drawing, showing the filtrate of Reference Example 1. [Figure 5]FIG. 5 is a photograph, instead of a drawing, showing the filtrate of Reference Example 2. [Figure 6] FIG. 6 is a photograph, instead of a drawing, showing the filtrate of Reference Example 3. [Figure 7] FIG. 7 is a photograph, in place of a drawing, showing the reference filtrate. [Figure 8] FIG. 8 is a graph, instead of a drawing, showing the filtration rates in Example 1 and Reference Examples 1 to 3. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention is not limited to the embodiments described below, but also includes appropriate modifications of the embodiments below within the scope obvious to those skilled in the art.

[0013] The first invention relates to a filtration device. The filtration device is a device used to separate specific substances from a solution to be filtered. Any known filtration device can be used as long as it includes a filtration section that includes a filter cloth (filter section) and an inorganic layer provided in the filter section. An example of a filtration device is a (rotary drum type) precoat filter. The precoat filter supplies a filter aid slurry to form a precoat layer (inorganic layer) on the filter cloth. The solution to be filtered is then filtered, and the precoat layer is continuously scraped off, constantly updating the filtration surface while filtering. The filtration device may include a plurality of known filters connected together. The filtration device may also be a rotary drum type filter without a precoat layer. A preferred use of the filtration device is body feed filtration, in which a filter aid (body feed agent) is directly added to the raw solution to be filtered and the solution is filtered using a rotary drum type filter.

[0014] An example of the filter section is a filter cloth. The filter is preferably made of at least one material selected from the group consisting of resin, metal, and ceramic, more preferably made of at least one material selected from resin and metal, and may be made of metal (e.g., stainless steel). When the filter cloth is made of resin, the resin constituting the filter cloth is preferably a resin fiber such as polypropylene, polyester, polyamide, or nylon. By using a filter made of such a material, the filtration efficiency of the filtration process can be more effectively improved. The mesh size of the filter can be adjusted appropriately depending on the application, and is preferably 0.1 μm or more, more preferably 1 μm or more, even more preferably 5 μm or more, and particularly preferably 10 μm or more. The mesh size of the filter is preferably 5 mm or less, more preferably 1 mm or less, and even more preferably 100 μm or less. A plurality of concave and convex portions may be provided on the entire surface of the filter in advance. In this way, the inorganic layer can be easily laminated, thereby improving the filtration efficiency. An example of the unevenness is a grid-like unevenness, and the unevenness may have a height of 1 mm to 50 mm, or 5 mm to 30 mm. The period of the undulations may be, for example, 1 mm to 50 mm, or 5 mm to 30 mm.

[0015] The inorganic layer is an inorganic layer (e.g., a precoat layer) provided on the filter unit. This inorganic layer is usually laminated on the filter unit. The filter unit may be used to filter a filter aid slurry, thereby forming a precoat layer (inorganic layer) on the filter unit. The inorganic layer contains a first silica having a permeability of 1D or more and 5D or less, and a second silica having a permeability of 0.05D or more and 0.5D or less. In a preferred example of a filtration device, the first silica is fused calcined silica, and the second silica is calcined silica. The permeability of the first silica may be 1.5D or more and 3D or less, and the permeability of the second silica may be 0.1D or more and 0.4D or less. The inorganic layer may contain an inorganic substance such as silica, and may also contain an organic substance as appropriate. The content (weight ratio) of the first silica to the second silica in the inorganic layer may be 1:5 to 5:1, 1:4 to 4:1, or 1:3 to 3:1.

[0016] Permeability is an index that indicates how easily a porous object (porous) allows a fluid to pass through. The unit of permeability is D (darcy), and 1 darcy is 9.87 x 10 -13 m 2 The permeability is a physical quantity used to evaluate the physical properties of a filter aid. The permeability can be measured, for example, according to the method for measuring the permeability of a material in JISR 2115:2008, a test method for the permeability of refractories.

[0017] The average particle size of the filter aid containing the first silica and the second silica is preferably 1 to 150 μm, more preferably 10 to 100 μm, and even more preferably 15 μm to 50 μm. By setting the average particle size of the filter aid within the above range, the filtration efficiency can be more effectively improved. "Average particle size" refers to the 50% (d50) particle size (median diameter), which is the particle size at 50% of the total number of particles when the number of particles is counted from the smallest particle size using a laser diffraction particle size distribution measuring device.

[0018] The thickness of the inorganic layer is preferably 10 mm to 500 mm, and may be 30 mm to 300 mm, 50 mm to 200 mm, or 50 mm to 150 mm. The porosity of the inorganic layer is preferably 50% to 99%, and may be 60% to 95%, or 80% to 90%. The surface of the inorganic layer may be scraped off as the filtration progresses.

[0019] The inorganic layer may contain another silica in addition to the first silica and the second silica, or may further contain any one or more of diatomaceous earth, alumina, iron oxide, alkali metal oxide, perlite, powdered cellulose, and activated carbon in addition to the first silica and the second silica.

[0020] The inorganic layer can be produced, for example, by supplying a slurry containing the first silica and the second silica to a filter section, and repeating the process of adhering the slurry to the filter section to increase the thickness of the inorganic layer.

[0021] The components of the filtration device other than the filter portion and inorganic layer can be those of a known filtration device. Filtration may be performed by passing the raw liquid (liquid to be filtered) through the inorganic layer and filter portion. In this case, the raw liquid may be suctioned to increase the filtration efficiency.

[0022] A preferred example of the filtration device further includes a temperature adjustment unit for adjusting the temperature of the stock solution to be filtered. In this example, the temperature of the stock solution before contact with the inorganic layer and the temperature of the stock solution in contact with the inorganic layer are adjusted using the temperature adjustment unit. An example of the stock solution is a solution containing a colorant such as a dye or pigment. The colorant may be dissolved or may be undissolved. In addition to the dye or pigment, the stock solution may further contain styrene or a styrene-containing polymer. As shown in the examples, the filtration device of this invention can effectively separate the dye or pigment from the styrene or styrene-containing polymer.

[0023] An example of a temperature adjustment unit is one that comes into contact with the concentrate or includes a heat source (e.g., a boiler or heater) that can heat the container portion that contains the concentrate. By including a heating element such as a heat source, the container portion can be appropriately heated. In particular, when the concentrate contains dyes or pigments, it is preferable to perform filtration while reducing the viscosity of these. From this perspective, it is preferable to perform filtration using a filtration device while using a temperature adjustment unit to maintain the temperature of the solution at room temperature or higher and 100°C or lower (preferably 50°C or higher and 100°C or lower, 60°C or higher and 95°C or lower, or 70°C or higher and 90°C or lower).

[0024] Fig. 1 is a diagram illustrating an example of a rotary drum filter. A filter cloth is fixed to the drum surface to form an inorganic layer (cake layer) on the outside of the drum. This filter is equipped with a cutter to cut and discharge the cake filtered on the filter surface together with the auxiliary agent.

[0025] Figure 2 shows an example of the basic flow of filtration using a rotary drum filter. [Example]

[0026] In the following examples, a mixed solution of 90% styrene, 9.6% polystyrene, and 0.4% pigment (hereinafter referred to as the "mixed solution") was filtered with the aim of removing the pigment to below the critical concentration. The pigment was thought to contain a mixture of carbon black and other pigments. A rotary drum filter was used as the filtration device. A filter cloth manufactured by Nakao Filter Industry Co., Ltd. was used as the filter material.

[0027] Filtration Method Cake from the raw solution accumulated in the cake layer (inorganic layer). When the drum was rotated, this cake was removed by a cutter along with a cake layer (inorganic layer) of a certain thickness. The filtration conditions were a suction pressure of 500 mmHg.

[0028] (Example 1) Mixed filtration of filter aid A and filter aid B As filter aids, Silica 600H manufactured by Chuo Silica Co., Ltd. (hereinafter referred to as "filter aid A") and Silica 300S manufactured by the same company (hereinafter referred to as "filter aid B") were used. The properties of filter aids A and B are shown in Table 1 below. In this example, a mixture of filter aid A at a concentration of 10% and filter aid B at a concentration of 5% was used as the body feed agent. The test temperature was 21.6°C, and the rotating drum was rotated at a rotation frequency of 8 min / R to filter the mixture, obtaining the filtrate shown in Figure 3. The filtration rate was 0.133 m 3 / (m 2 ·hr).

[0029] [Table 1]

[0030] (Reference Example 1) Filtration with filter aid A alone In this reference example, only 10% filter aid A was used as the body feed agent. The test temperature was 50.0°C, the rotating drum was rotated at a rotation frequency of 12 min / R, and the mixed liquid was filtered to obtain the filtrate shown in Figure 4. The filtration rate was 0.133 m 3 / (m 2 ·hr).

[0031] (Reference Example 2) Filtration with filter aid B alone In this reference example, only 20% filter aid B was used as the body feed agent. The test temperature was 22.2°C, the rotating drum was rotated at a rotation frequency of 23.3 min / R, and the mixed liquid was filtered to obtain the filtrate shown in Figure 5. The filtration rate was 0.044 m 3 / (m 2 ·hr).

[0032] (Reference Example 3) Serial filtration of filter aid A and filter aid B In this reference example, a 10% concentration of filter aid A was used as a body feed agent for pretreatment, and the mixed liquid was filtered at a test temperature of 22.2°C by rotating the rotary drum at a rotation frequency of 14 min / R. The pre-filtration speed for pretreatment was 0.116 m 3 / (m 2 ·hr).

[0033] Next, a 5% concentration of filter aid B was used as a body feed agent, and the test temperature was 23.1°C. The rotating drum was rotated at a rotation frequency of 12 min / R, and the filtrate produced in the pretreatment was filtered to obtain the filtrate shown in Figure 6. The finishing treatment filtration speed was 0.089 m 3 / (m 2 (Hereinafter, this series of filtration steps will be referred to as "serial filtration.")

[0034] [Visual evaluation of filtrate color] The filtrate colors obtained in Example 1 and Reference Examples 1 to 3 (FIGS. 3 to 6) were compared with the target filtrate color in FIG. 7 and visually evaluated. FIG. 7 shows the target filtrate. As can be seen from FIGS. 3 to 7, the filtrate colors obtained in Example 1 and Reference Examples 2 and 3 (FIGS. 3, 5, and 6) were comparable to the target filtrate color (FIG. 7). It was confirmed that the pigment was sufficiently filtered from the mixed liquid in Example 1 and Reference Examples 2 and 3.

[0035] [Filtration speed] The filtration rates in Example 1 and Reference Examples 1 to 3 are shown in Fig. 8. From Fig. 8, it was confirmed that the filtration rate in Example 1 was comparable to that in Reference Example 1 and was greater than that in Reference Examples 2 and 3.

[0036] The above results demonstrate that the mixed filtration of filter aid A and filter aid B (Example 1) can sufficiently and quickly filter pigments from the mixed solution. If a filtration system based on Reference Example 3, in which two filtration systems are connected in series, is implemented, a two-stage filtration system is required, making the system large-scale. On the other hand, the filtration system of Example 1 can effectively remove pigments with a single filtration system, so it is believed that a smaller system would suffice. The above-mentioned effects are believed to be due to the fact that the inorganic layer is formed by mixing multiple types of silica with significantly different transmittances. Therefore, the present invention is not limited to the use of the two types of silica shown in the examples, but is believed to extend to the use of an inorganic layer in which multiple types of silica with transmittances within a predetermined range are mixed. [Industrial Applicability]

[0037] The present invention can separate color components such as dyes and pigments from a raw solution, and therefore can be preferably used in the chemical industry, printing industry, and recycling industry.

Claims

1. A filtration device including a filter unit and an inorganic layer provided on the filter unit, The filtration device, wherein the inorganic layer includes a first silica having a permeability of 1D or more and 5D or less, and a second silica having a permeability of 0.05D or more and 0.5D or less.

2. 2. The filtration device of claim 1, the first silica is a fused-calcined silica; The second silica is pyrogenic silica, the filtration device.

3. 2. The filtration device of claim 1, The transmittance of the first silica is 1.5D or more and 3D or less, The permeability of the second silica is 0.1D or more and 0.4D or less.

4. 2. The filtration device of claim 1, The filtration device further comprises a temperature adjusting unit for adjusting the temperature of the raw liquid to be filtered.

5. A filtration method for filtering a solution containing a dye or pigment, using the filtration device according to claim 1.

6. 6. The method of claim 5, wherein the solution further comprises styrene or a styrene-containing polymer.

7. The filtration method according to claim 5 , comprising the step of performing filtration using the filtration device while maintaining the temperature of the solution at room temperature or higher and 100° C. or lower.

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