Limonite composite fiber, air conditioning filter and air conditioning system using the same, and method for producing limonite composite fiber

Abstract

To provide a fibrous limonite composite fiber capable of increasing the adsorption efficiency of gas-phase hydrogen sulfide.SOLUTION: By mixing limonite powder with a porous carrier resin (polyether sulfone (PES)), using N-methyl-2-pyrrolidone (NMP) as a solvent, and setting the carrier resin and the solvent to a predetermined blending ratio, it becomes possible to increase the surface area of the limonite powder and also achieve durability as a limonite composite fiber.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a limonite composite fiber capable of increasing the adsorption and removal amount of hydrogen sulfide and having excellent durability, an air-conditioning filter using the same, an air-conditioning system, and a method for producing the limonite composite fiber.

Background Art

[0002] When an air conditioner is installed in an area where hydrogen sulfide is generated, such as a hot spring, the copper pipes and heat exchangers inside the air conditioner are corroded by hydrogen sulfide, causing pitting corrosion and gas leakage.

[0003] Therefore, conventionally, the copper pipes inside the air conditioner were electroplated with cationic paint or the heat exchanger was coated with corrosion-resistant paint, but these were not sufficient countermeasures. Eventually, the copper pipes and heat exchangers were corroded over time, causing pitting corrosion and gas leakage.

[0004] In recent years, a functional nonwoven fabric with limonite powder attached has been introduced by utilizing the adsorption effect of limonite on hydrogen sulfide (Patent Document 1).

[0005] Specifically, a functional nonwoven fabric in which limonite powder is attached to fibers constituting the functional nonwoven fabric (for example, polyethylene fibers, polypropylene fibers, etc.) via a binder (for example, polyester-based latex, acrylic-based latex, etc.) is used as an air-conditioning filter, and by installing this filter at the air inlet of the air conditioner's air passage, hydrogen sulfide entering the air conditioner interior and the air flow path is adsorbed and removed to prevent corrosion of the copper pipes and heat exchangers inside the air conditioner.

[0006] Also, Patent Document 2 describes a fibrous carrier resin in which zeolite is dispersed and a method for producing the same.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] By the way, in the invention described in Patent Document 1, in order to increase the adsorption amount of hydrogen sulfide, it is conceivable to increase the amount of limonite powder attached to the fibers as a non-woven fabric and increase the particle density (content rate). For example, when mixing limonite powder with non-woven fabric fibers at 50% by mass or more, the particle density of the limonite powder increases, but the adsorption treatment rate is said to slow down, and there is an upper limit to the surface area of the limonite powder per unit area of the functional non-woven fabric.

[0009] In addition, in the functional non-woven fabric described in Patent Document 1, since the limonite powder is attached to the fibers as a non-woven fabric via a binder, much of the surface of the limonite powder is covered by the binder, and there is a problem that the total surface area of the limonite powder does not become as wide as the amount of limonite.

[0010] Therefore, in order to increase the total surface area of the limonite powder, it is conceivable to make the functional non-woven fabric into multiple layers by folding it, etc. However, when the functional non-woven fabric is made into multiple layers, there is a new problem that the pressure loss of the air flow path increases, and there are adverse effects on the air conditioning equipment such as a decrease in the air volume and an increase in power consumption.

[0011] The radioactive cesium adsorption fiber (carrier resin) described in Patent Document 2 removes and recovers radioactive cesium dissolved in water, and is used in a so-called aqueous system (liquid phase). The cesium adsorbing substance is zeolite, and zeolite is relatively porous.

[0012] However, the radioactive cesium adsorption fiber described in Patent Document 2 cannot adsorb the substance to be adsorbed (hydrogen sulfide H2S) in the gas phase (gas phase).

[0013] In order to remove the adsorbed substance (hydrogen sulfide, H2S) from a gas system (vapor phase), the amount of adsorbed substance (hydrogen sulfide, H2S) adsorbed is greatly affected by the amount of contact with the adsorbed substance, so it is particularly important to increase the pore volume and specific surface area of ​​the carrier resin.

[0014] Therefore, the present invention focuses on a material in which limonite powder is embedded in a porous resin without using a binder, and its object is to provide a limonite composite fiber that can increase the total surface area of ​​a composite material with limonite powder and resin to increase the adsorption efficiency of gaseous (vapor phase) adsorbents, thereby increasing the amount of hydrogen sulfide removed, and that is also highly durable, as well as an air conditioning filter and air conditioning system that use the same, and a method for producing the limonite composite fiber. [Means for solving the problem]

[0015] In order to achieve the above-mentioned object, the invention described in claim 1 is a limonite composite fiber, characterized in that limonite powder is mixed with a carrier resin that forms a porous material and formed into a fibrous composite.

[0016] The invention described in claim 2 is characterized in that in the limonite composite fiber described in claim 1, the carrier resin is polyethersulfone (PES).

[0017] The invention described in claim 3 is an air conditioning filter using the limonite composite fiber described in claim 1 or claim 2, characterized in that the limonite composite fibers are randomly intertwined so as to be entangled, and stored in a mesh-like storage body having a predetermined volume.

[0018] The invention described in claim 4 is an air conditioning system using the air conditioning filter described in claim 3, characterized in that the air conditioning system comprises an air passage, an air conditioner arranged in the air passage, and the air conditioning filter arranged in the air passage.

[0019] The invention according to claim 5 is a method for manufacturing a limonite composite fiber according to any one of claims 1 to 4, characterized in that the limonite powder, the carrier resin, and a solvent are mixed, a predetermined pressure is applied thereto, and the mixture is discharged from a cylinder and immediately put into water for manufacturing.

[0020] The invention according to claim 6 is a method for manufacturing a limonite composite fiber according to claim 5, characterized in that the solvent is N-methyl-2-pyrrolidone (NMP).

Advantages of the Invention

[0021] According to the invention described in claim 1, by mixing limonite powder with a porous carrier resin and forming a fibrous composite, the surface area of the limonite powder can be increased, and accordingly, the amount of hydrogen sulfide removed can be increased.

[0022] According to the invention described in claim 2, since the carrier resin is polyethersulfone (PES), the carrier resin has excellent heat resistance, steam resistance, and creep resistance, and is less likely to undergo aging changes. Therefore, hydrogen sulfide can be removed over a long period of time.

[0023] According to the invention described in claim 3, since the limonite composite fiber is used as an air-conditioning filter by being housed in a mesh-shaped housing, the air-conditioning filter can be easily and replaceably arranged in the air supply duct of the air-conditioning equipment.

[0024] According to the invention described in claim 4, since the air-conditioning filter is provided in the air supply passage of the air-conditioning equipment, hydrogen sulfide can be efficiently removed, and an air-conditioning system in which the air-conditioning filter can be easily replaced can be constructed. Corrosion of the air-conditioning equipment in the air-conditioning system, particularly pipes and heat exchangers, can be avoided, and their service life can be extended.

[0025] According to the invention described in claim 5, in the production of the limonite composite fiber, a mixture of limonite powder, carrier resin, and solvent is subjected to a predetermined pressure and discharged from a cylinder, and immediately after that, it is put into water. By doing so, after immersion, the solvent dissolves in water, and during the process where the resin precipitates in water, voids are formed in the space containing water and the solvent between the resins, resulting in a porous structure. By encapsulating the water-insoluble limonite powder and complexing it, the surface area of the limonite powder is increased, and a limonite composite fiber with a large hydrogen sulfide adsorption amount can be produced.

[0026] According to the invention described in claim 6, in the production of the limonite composite fiber, since the solvent is N-methyl-2-pyrrolidone (NMP), the limonite composite fiber can be produced inexpensively and efficiently.

Brief Description of the Drawings

[0027]

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Embodiments for Carrying Out the Invention

[0028] Hereinafter, this invention will be described based on the illustrated embodiments.

[0029] (Embodiment) FIG. 1 shows the limonite composite fiber 1 and the limonite powder according to this embodiment. The limonite composite fiber 1 in a state of being stacked and bundled in a single ring shape (FIG. 1(a)) is formed by mixing the limonite powder 3 (FIG. 1(b)) with the porous carrier resin 2 to form a fibrous composite. Such a limonite composite fiber 1 can be produced by mixing the limonite powder 3, the carrier resin 2, and the solvent 4, applying pressure to these at a predetermined temperature, and discharging them into water to form the composite fiber 1 as a fibrous composite. At this time, the carrier resin 2 functions to hold the limonite without using a binder, and the limonite powder 3 is dispersed and embedded in the porous carrier resin 2.

[0030] In addition, polyethersulfone (PES) was used as the carrier resin 2. However, other thermoplastic resins such as polysulfone, 6,6-nylon, 6-nylon, polyacrylonitrile, and polystyrene sulfonic acid are also conceivable. Nevertheless, PES was preferable in terms of its ability to withstand the corrosion of hydrogen sulfide and its overall chemical resistance, heat resistance, etc.

[0031] Moreover, N-methyl-2-pyrrolidone (NMP) was used as the solvent 4. However, other solvents such as formic acid, n-butanol, N,N-dimethylformamide, and tetrahydrofuran are also conceivable. Nevertheless, NMP was preferable overall.

[0032] Specifically, the production apparatus 10 for the limonite composite fiber 1 includes an air compressor 11, a pressure regulator 12, a hose 13, a cylinder 14, a needle 15, and a water tank 16.

[0033] The air compressor 11 is connected to the pressure regulator 12 and the cylinder 14 via the hose 13. The cylinder 14 is pre-supplied with the melted composite 1a obtained by mixing the limonite powder 3, the carrier resin 2, and the solvent 4 and heating them to a predetermined temperature (see Figure 2).

[0034] When the air compressor 11 is started, the air pressure sent out by the pressure regulator 12 is adjusted, and air is supplied into the cylinder 14.

[0035] When the inside of the cylinder 14 is pressurized, the melted composite 1a is discharged from the needle 15 at the tip of the cylinder 14 in a fibrous form and is put into the water 17 in the water tank 16 placed below the cylinder 14, where it hardens to form a continuous single limonite composite fiber 1 (see Figure 1).

[0036] By the way, in order to use the present invention as a gas-phase adsorbent (filter), in order to increase the adsorption amount of the substance to be adsorbed (hydrogen sulfide H2S), it is effective to increase the specific surface area and pore volume of the carrier resin 2 and the limonite powder 3.

[0037] In order to adsorb more H2S, increasing the content rate of limonite powder 3 in the limonite composite fiber 1 and increasing the specific surface area of the limonite powder 3 were considered.

[0038] As a premise, the particle size of the limonite powder 3 is generally 0.01 to 500 μm, which easily penetrates into the pores of the carrier resin 2 and has a large specific surface area, so an increase in the adsorption amount can be expected. However, when the particle size is less than 0.01 μm, the aggregability of the particles increases and it becomes difficult to disperse them in the carrier resin 2. Also, when the particle size exceeds 500 μm, it is said that the adsorption rate of hydrogen sulfide and the like decreases, and the specific surface area of the limonite powder is 0.1 m 2 / g or more is preferable, and when the specific surface area is less than 0.1 m 2 / g, functions such as the adsorption effect become insufficient.

[0039] First, the content rate of the limonite powder 3 was examined. If the content rate of the limonite powder 3 is increased, the opportunity of contact with H2S increases accordingly, and the adsorption rate of H2S is promoted. On the other hand, if the content rate of the limonite powder 3 is increased, the proportion of the carrier resin 2 will decrease, and it is expected that the durability as the limonite composite fiber 1 will become a problem. Therefore, the content rate of the limonite powder was set with an upper limit of 60 wt%.

[0040] Therefore, the specific surface area and pore volume of the limonite powder, PES resin, 20 wt% limonite composite fiber, 40 wt% limonite composite fiber, and 60 wt% limonite composite fiber were determined respectively (see Figure 3).

[0041] As a result, it was found that the specific surface area of the limonite powder 3 alone is the largest, and for the limonite composite fiber 1, the one with a higher content rate (20 wt% < 40 wt% < 60 wt%) has both a larger surface area and a larger specific surface area. Therefore, in the subsequent verification, it will be carried out with the 60 wt% limonite composite fiber.

[0042] Next, in order to optimize the blending amounts of the solvent 4 and the carrier resin 2 for making the limonite composite fiber 1 porous, the ratio of the solvent 4 is changed during the production of the limonite composite fiber 1, and three types with the ratio of NMP to PES being 9:1, 8:2, and 7:3 are prepared, and the BET surface area of each is determined.

[0043] This is because, in the manufacturing process of the limonite composite fiber 1, the incorporated solvent 4 dissolves in water 14, creating voids accordingly and resulting in a porous structure. This is because the ratio of the carrier resin 2 to the solvent 4 affects the specific surface area. That is, by changing the weight ratio of the solvent (NMP) in which the limonite powder 3 is dispersed to the carrier resin (PES), the porosity of the PES around the limonite powder after solidification in water can be changed.

[0044] First, with a limonite content of 60 wt%, the ratio of NMP to PES is changed as follows: · NMP:PES = 9:1 is designated as CF10 · NMP:PES = 8:2 is designated as CF20 · NMP:PES = 7:3 is designated as CF30 As a result, the cross-section and surface of each limonite composite fiber 1 photographed with a scanning electron microscope (SEM) are shown in Fig. 4.

[0045] As can be seen from Fig. 4, it was found that when there is more NMP (more substances dissolve: CF10), there are more large pores, and when there is less NMP (fewer substances dissolve: CF30), there are more sponge-like pores in the resin surrounding the limonite.

[0046] From this, it can be inferred that the limonite composite fiber 1 of CF10 has a larger specific surface area than the limonite composite fiber 1 of CF30.

[0047] Next, the BET surface area of each of the above limonite composite fibers 1 is determined.

[0048] Generally, to determine the surface area of a porous material, a BET adsorption test is performed to determine the surface area.

[0049] The BET adsorption test involves placing a porous material and a gas (here nitrogen (N2)) in the apparatus, changing the pressure (or concentration), measuring the amount of nitrogen adsorbed by the porous material, and obtaining a nitrogen adsorption isotherm (see Figures 5(a) and (b)).

[0050] For comparison, the BET surface areas of limonite powder alone (Limonite) and the carrier resin (PF10) without limonite are listed. PF10 is made of fibers without limonite, only PES and NMP.

[0051] From the nitrogen adsorption isotherm, a BET plot graph is created by a general method, and from the BET plot graph, the BET surface area of each limonite composite fiber 1 is obtained (see Figure 5(c)).

[0052] As a result, the one with more NMP (more substances dissolve: CF10) has a larger surface area, and the one with less NMP (fewer substances dissolve: CF30) has a smaller surface area, obtaining the same result as the above SEM image.

[0053] Figures 6 and 7 are diagrams showing the results of comparing the BET surface areas of each limonite composite fiber 1 before and after H2S adsorption (after 672 hours (28 days)) in a 200 ppm H2S environment.

[0054] In the figure, (a) shows the nitrogen adsorption isotherm, (b) shows the relationship between pore volume and pore diameter, and (c) shows the specific surface area.

[0055] As can be seen from Figures 6 and 7, for any limonite composite fiber 1, the BET surface area after 672 hours has significantly decreased ((c) figure), and it is considered that more H2S has been adsorbed corresponding to the decrease in surface area.

[0056] Also, it can be seen that the adsorption amount of H2S is larger for CF10 (the one with a larger surface area) than for CF30 (the one with a smaller surface area) at any time.

[0057] As can be seen from FIGS. 6(b) and 7(b), since the pore volume near a pore diameter of 3 nm is most decreased, it is recognized that H2S has a large adsorption amount at a pore diameter near this value. In the case of CF10, it is considered that the pores near this 3-nm pore diameter contribute more to the adsorption of H2S than those of the other CF20 and CF30.

[0058] Figs. 8 to 10 show the nitrogen adsorption isotherm and the relationship between the pore volume and the pore diameter obtained by the BET adsorption experiment. Further, from the results of the BET surface area, the monolayer adsorption amount (Qm) and the adsorption equilibrium constant (K) are calculated, and each limonite composite fiber 1 can be compared by Qm.

[0059] In FIG. 8, a comparison is made between each limonite composite fiber and only PES using a nitrogen adsorption isotherm with the concentration on the horizontal axis.

[0060] In the graph of FIG. 8, substances with a large adsorption area adsorb more when the concentration is low, and reach equilibrium as the concentration increases. Therefore, the adsorption saturation amounts of the respective limonite composite fibers 1 can be compared.

[0061] The results of calculating the monolayer adsorption amount (Qm) and the adsorption equilibrium constant (K) from the BET surface area of each limonite composite fiber 1 are as shown in FIG. 10.

[0062] From these results, it is certain that the adsorption amount of CF10 is the best. However, when comparing Qm, it can be seen that the difference is not large. Considering that CF10 with a small amount of carrier resin (PES) is brittle, it is also conceivable to use CF30 with high strength as the limonite composite fiber 1.

[0063] In short, if only the adsorption performance is considered, CF10 should be selected. However, when actually used as an air-conditioning filter, if a certain degree of durability is also required, CF30 may be selected.

[0064] As described above, in the limonite composite fiber 1 of the present invention, as a gas adsorbent, in addition to the content of the limonite powder 3, by considering the ratio of the carrier resin 2 and the solvent, a resin as an adsorbent with a high adsorption rate and excellent durability can be provided.

[0065] Next, an air conditioning system 20 using such limonite composite fiber 1 will be described.

[0066] For example, in a hot spring area or the like, hydrogen sulfide H2S may be generated, and the hydrogen sulfide H2S that has invaded a building, a room, etc. is harmful to human health. Therefore, it is necessary to remove the hydrogen sulfide H2S that has invaded a room or a living room.

[0067] Therefore, the above limonite composite fiber 1 is used for the air conditioning filter 23 of an air conditioning system (air conditioner) 20 installed in a room or a living room.

[0068] FIG. 11 is a schematic diagram briefly showing the air conditioning system 20, which has a blower passage 21 serving as an air passage, an air conditioner 22 for adjusting the temperature, and an air conditioning filter 23 installed upstream of the air conditioner 22 in the blower passage 21.

[0069] In such an air conditioning system 20, when the air conditioner 22 is started and air is taken in from the blower passage 21, first, the taken-in air comes into contact with the air conditioning filter 23 upstream of the air conditioner 22.

[0070] Then, since the air that has come into contact with the limonite composite fiber 1 of the air conditioning filter 23 has the above-described structure, the hydrogen sulfide H2S in the taken-in air is efficiently adsorbed and removed by the limonite composite fiber 1.

[0071] It is difficult for all of the hydrogen sulfide H2S in the air that has come into contact with the air conditioning filter 23 to be adsorbed by the above limonite composite fiber 1. Therefore, the concentration of hydrogen sulfide H2S is gradually diluted as the air in the room or living room circulates through the air conditioning system 20.

[0072] Using such a air-conditioning filter 23 in the air-conditioning system 20 enables the limonite composite fiber 1 to efficiently remove hydrogen sulfide H2S (at least more efficiently than the functional nonwoven fabric as in Patent Document 1), and thus can efficiently purify the air in a room or indoor space.

[0073] Of course, it is preferable that the hydrogen sulfide in the air passing through the air-conditioning filter 23 once is adsorbed and removed by the air-conditioning filter 23. However, for this purpose, a huge amount of limonite composite fiber 1 is expected to be required. Therefore, it is preferable to determine the amount of limonite composite fiber 1 in consideration of the volume of the room, the performance (wind force) of the air conditioner 22, etc.

[0074] Since the limonite composite fiber 1 of the present invention is manufactured as a continuous single fibrous material by the manufacturing method as described above, the handling of the air-conditioning filter 23 can be extremely simplified.

[0075] That is, the air-conditioning filter 23 can be formed by simply winding or randomly intertwining the above-mentioned limonite composite fiber 1 in a mesh-shaped storage body 24 having a predetermined volume. Also, since it is a continuous single fibrous material, it is only necessary to continuously push it into the mesh-shaped storage body 24, and it will not be damaged even if it is handled relatively roughly.

[0076] Although the limonite composite fiber 1 has been described as a continuous single one, a plurality of limonite composite fibers 1 that do not come apart may be stored in the mesh-shaped storage body 24. However, if a large number of short-length limonite composite fibers 1 are to be stored in the mesh-shaped storage body 24, they may be stored offset to the lower side of the mesh-shaped storage body 24. Therefore, it is preferable to determine the length of the limonite composite fiber 1 so that it is uniformly stored in the mesh-shaped storage body 24 in consideration of the volume (inner dimensions, etc.) of the mesh-shaped storage body 24.

[0077] When replacing the air conditioner filter 23, for each mesh-shaped storage body 24, it is possible to replace it with a new one containing the limonite composite fiber 1, or the limonite composite fiber 1 can be taken out from the mesh-shaped storage body 24 on-site and a new limonite composite fiber 1 can be stored therein.

[0078] The mesh-shaped storage body 24 may be one in which the periphery of a metal frame is surrounded by a wire mesh or the like, or may simply be something like a net-shaped bag body.

[0079] As described above, by using the limonite composite fiber 1 according to the embodiment as the adsorbent of the air conditioner filter 23, a high-performance material as an adsorbent for hydrogen sulfide H2S can be easily used.

[0080] In the above embodiment, the present invention has been described as the air conditioner filter 23 of the air conditioner 22 installed in a room or a living room, but it is not limited thereto, and it can also be used as the air conditioner filter 23 of the outdoor unit. That is, it takes in outside air and changes it to a comfortable temperature, humidity, etc. By providing the above-described air conditioner filter 23 on the upstream side of the blower fan of such an outdoor unit, the air conditioning environment in the building can be improved. In addition, in the case of an outdoor unit, many air conditioning equipment pipes, heat exchangers, etc. are provided, and corrosion caused by their contact with hydrogen sulfide H2S can be suppressed.

[0081] Although the embodiments of this invention have been described above, the specific configuration is not limited to the above embodiments, and even if there are design changes, etc. within the scope not departing from the gist of this invention, they are included in this invention.

Explanation of Reference Numerals

[0082] 1 Limonite composite fiber 2 Carrier resin (PES (polyethersulfone)) 3 Limonite powder 4 Solvent (NMP (N-methyl-2-pyrrolidone)) 10 Manufacturing apparatus 14 Cylinder 17 Water 20 Air conditioning system 21 Air duct 22 Air conditioner 23 Air conditioning filter 24 Mesh-shaped storage body

Claims

1. Limonite powder is mixed with a porous carrier resin to form a fibrous composite. Limonite composite fiber.

2. The carrier resin is polyethersulfone (PES); The limonite composite fiber according to claim 1 .

3. The limonite composite fibers are randomly intertwined so as to be entangled, and stored in a mesh-like container having a predetermined volume.

3. An air conditioning filter using the limonite composite fiber according to claim 1 or 2.

4. The air conditioner includes an air passage, an air conditioner disposed in the air passage, and the air conditioning filter disposed in the air passage.

4. An air conditioning system using the air conditioning filter according to claim 3.

5. The limonite powder, the carrier resin and the solvent were mixed, and then discharged from a cylinder under a predetermined pressure, and immediately afterwards, the mixture was poured into water to produce the product. The method for producing the limonite composite fiber according to any one of claims 1 to 4.

6. The solvent is N-methyl-2-pyrrolidone (NMP); The method for producing limonite composite fiber according to claim 5,

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