JP2009119448A - Air cleaner of fluidized bed type using organic foam serving as bed material and catalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost air cleaner which has functions of deodorization, bacteria elimination and organic substance decomposition by using a fluidized bed method using catalyst as light-weight bed material. <P>SOLUTION: Granular catalyst prepared by depositing a water-soluble ceramic oxidation-reduction agent of inorganic oligomer of silicic acid, phosphoric acid or the like on granular foam made of polystyrene, polyethylene, polylactide resin or the like which is coated with a porous material such as active carbon and bamboo carbon is used as the bed material, is allowed to efficiently catalytically-react with contaminated air in a fluidized bed, at the same time, catalyst liquid is properly supplied by spraying by using a catalyst dropping device for replenishment disposed near a blower port in the device and, thereby, the adsorption and oxidative decomposition is caused such that odorous substance such as ammonia and hydrogen sulfide, and volatile harmful organic substance such as formalin and acetaldehyde are decomposed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, a lightweight spherical organic foam is used to support fine powder of bamboo charcoal and a water-soluble ceramic redox agent of inorganic oligomer such as silicic acid or phosphoric acid thereon, or a catalyst carrying the redox catalyst and platinum fine particles. The present invention relates to a fluidized bed type air purifier that is used as a fluidized medium to enhance the adsorption / decomposition ability of organic substances in a low temperature range.

  Conventionally, there are many methods for removing and decomposing harmful components and odorous components of air, but general methods that have been put to practical use include adsorption removal methods using adsorbents, decomposition and removal methods using plasma discharge, and ozone. Decomposition, removal method, and adsorption / decomposition method combined with adsorbent and oxidation catalyst or photocatalyst.

  In the adsorption removal method, a porous material such as activated carbon or zeolite is used as an adsorbent. As an example of using activated carbon, there is a method of removing odor component gas by bringing it into contact with a fluidized activated carbon layer in a filter container (Patent Document 1). As the odor substance is adsorbed, there are problems that the saturated state is reached and the performance is lowered and the deodorization efficiency is deteriorated. There is a type of activated carbon in which the power required for fluidization increases and the removal performance is inferior depending on the type of odor component, and it is also necessary to select activated carbon according to the type of odor component.

  The plasma or ozone method is a method in which plasma, radical groups, ozone, and the like are generated by a high-voltage power source to decompose odor components and harmful components. Although these purification methods have been widely put into practical use, there are problems such as high equipment cost, harmful ozone leakage control, and high power costs due to the addition of high voltage. In addition, intermediate reactants and active species are generated in the reaction process, which may cause deterioration of the catalyst and re-release into the room.

  The combination of the adsorbent and the oxidation catalyst method is a method combining a metal-based oxidant for the purpose of removing odors and acetaldehyde generated in the living space (Patent Document 2) and in order to improve the reaction efficiency, In order to improve the contact efficiency, an adsorbent and an oxidant are used in which an oxidation catalyst is made into an integrally molded structure (Patent Document-3), activated carbon or an oxidant is bound and solidified with a binder (Patent Document-4). (Patent Document-5), and a method of using a mixture of a manganese dioxide oxidizing agent and a hydrophobic zeolite adjusted to a particle size of 1 mm or less for efficient deodorization at low temperatures (Patent Document-6) Etc. have been devised.

  A technology for decomposing harmful components in the atmosphere using a photocatalyst has also been developed, and various systems using a titanium oxide photocatalyst have been put into practical use. The photocatalyst method has a problem that the reaction rate is slow and the contact efficiency is inferior, and a method of using a photocatalyst and an adsorbent in combination or a method of processing into a sheet shape has been devised, but it is not sufficient. For this reason, photocatalyst media aiming at improving the reaction efficiency of the photocatalyst have been proposed. Forming platinum metal fine particles and titanium oxide as a photocatalyst layer and adjusting the atmospheric humidity at the time of decomposition to improve the catalytic activity (Patent Document-7), or separating the activated carbon sheet and the photocatalyst supporting fiber sheet, the photocatalyst There has been proposed a method (Patent Document-8) or the like that exhibits a greater effect.

Since the photocatalyst method needs to apply light to the photocatalyst universally, a combination of a photocatalyst and a mechanism that spreads light evenly by placing an inorganic fiber body with a three-dimensional network structure supporting the photocatalyst around the ultraviolet lamp (Patent Document 9), a method of applying ultraviolet rays uniformly from a fixed light source by stirring and displacing the photocatalyst with an air stream has been proposed.
(Patent Document-10)

  Japanese Patent Application Laid-Open No. 2004-290791   JP 2006-255251 A   JP-A-11-57470   JP 2004-105265 A   JP 2004-129840 A   JP-A-2005-237997   JP 2000-317269 A   JP 2002-204928 A   JP2004-24461   JP2004 / 045660

  The present invention improves the decomposition ability of the catalyst and increases the contact efficiency between harmful components in the air and the catalyst, and is harmful to high efficiency at low temperatures without using energy such as light, ozone, high heat, and high power. It decomposes components and odor components. The present invention also provides an energy-saving, low-cost fluidized bed reaction type air purifier by extending the catalyst life by a catalyst replenishment method.

  Fluidized bed technology has long been known as a unit operation method for the purpose of improving reaction efficiency because of its high contact efficiency, and has been put into practical use as various engineering operation methods such as combustion, decomposition, and drying.

  For the purpose of accelerating the reaction of the photocatalyst, the method in which the photocatalyst is displaced by an air flow and the light emitted from the light source uniformly hits the photocatalyst (the above-mentioned Patent Document-10) is not clear in terms of conditions for flowing the fluid medium, and is simply photocatalytic particles Is displaced and moved. In a fluidized bed, it is most important to select an air volume and a flow rate that are commensurate with the mass of the fluid medium and the particles of that size. Thereby, it is possible to prevent a flushing phenomenon that causes the fluid medium to blow through and to create a good fluid state. Fluidization is started when the mass, air volume, and wind pressure of the particles selected as the fluid medium are balanced, and a highly efficient contact state is developed, but when the air volume and flow velocity are insufficient, the fluid state does not occur, If the flow velocity exceeds a certain level, the fluid medium floats and scatters and the fluid state is broken.

The photocatalytic method requires that the photocatalyst is always irradiated with light. Even in a fluidized state, the rear of the fluidized medium irradiated with light becomes a shadow, so that the decomposition reaction does not occur uniformly in the layer. Since the catalyst as the fluidized medium in the fluidized bed in this technique and the air flow are in uniform contact, the decomposition reaction occurs uniformly and continuously in the bed. In the fluidized bed, the surface area of the solid particles exposed to the fluid is said to reach 30,000 m ² in a 1 m ³ particle layer, so the reaction efficiency is high. In order to improve the reaction efficiency, it is necessary to create such a flow state.

  In order to solve the above-mentioned problems, the present invention aims to improve the catalytic cracking efficiency by a fluidized bed reactor comprising a granular foam made of polystyrene or polyethylene carrying a redox catalyst or a polylactic acid resin of a vegetable resin as a fluidized bed. It is.

  The granular foam is formed by coating a water-soluble ceramic redox catalyst composed of an oligomer such as silicic acid and phosphoric acid having an antistatic effect or by previously coating a porous body having electric double layer characteristics, on which silicic acid and A water-soluble ceramic redox catalyst comprising an oligomer such as phosphoric acid is coated, or the foam is coated with a water-soluble ceramic redox catalyst comprising an oligomer such as silicic acid or phosphoric acid and platinum ultrafine particles of 3 nm or less. It is a feature.

  The granular foam has a specific gravity of 0.04 or less, an average diameter of 1 mm or more and a diameter of 5 mm or less.

  The above fluidized bed reactor is coated with a water-soluble ceramic redox catalyst composed of oligomers of silicic acid, phosphoric acid, etc. and platinum ultrafine particles on the top of the air box of the fluidized bed reactor in order to maintain the catalyst as a fluid medium for a long time. The replenishment drip spraying device is provided.

  The granular catalyst of the fluidized bed reactor is packed in a cartridge-type catalyst tower that can be desorbed and exchanged, and is characterized in that a filter of 150 mesh or more and 300 mesh or less is attached to the upper and lower space end faces of the catalyst tower, This prevents the catalyst from falling and rectifies the wind rising from the lower wind box.

  In the above fluidized bed reactor, a motor fan is attached to the wind box in a direction perpendicular to the catalyst tower, and the blown wind is introduced into the fluidized bed by the wind reflector, creating a flow of strong and weak wind speed in the fluidized bed. It is characterized by causing internal circulation in the bed.

  As described above, in the present invention, harmful organic substances and odorous substances can be efficiently performed by the catalyst having high catalytic cracking efficiency and cracking ability by the low power fluidized bed system.

In general, fluidized media used in drying devices and boiler fluidized bed devices are activated alumina, zeolite, and sand particles, so that they can be used at high temperatures, but the specific gravity is 2 g / cm ³ to 3 g / cm ^3. However, a large amount of air is required to obtain a fluid state, and the power cost is high. Porous foams such as polystyrene, polyethylene, and polylactic acid resin of vegetable resin have a light specific gravity of about 0.03 g / cm ^{3 and} about 1/80 to 1/100 compared to alumina and zeolite. Since the fluidization start speed is proportional to the total weight of the fluidized medium bed, the required power cost for fluidization is extremely low, and it is possible to produce a fluidized bed apparatus that can control the fluidized state even with a small air volume and wind pressure.

  In addition, since a device for extending the life of the catalyst is installed, it is possible to prevent the catalyst effect from being saturated, and to prevent a decrease in reaction efficiency due to contamination or separation of the catalyst due to dust or dirt from the outside air.

  In the case of a small-sized household air purification device, when the catalyst is replaced, it is scattered around and refilling work is required. Therefore, the fluidized bed cylinder is a cartridge type filled with a catalyst in advance, and the replacement work can be simplified by exchanging it. Moreover, it can be used as a multifunctional air purifier by exchanging with a fluidized bed cylinder having another function. For example, by switching from a fluidized bed cylinder having a deodorizing function to a fluidized bed cylinder having an aroma diffusing function, it can be used as an aroma generator from air purification. Further, by using a fluidized bed cylinder coated with an antibacterial composition having an antibacterial effect against bacteria, molds, viruses, etc., it can be used as an air purification device for sterilization, sterilization and infection prevention.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  In the figure, reference numeral 1 denotes a wind box of the main body, and a motor fan 2 is attached to the intake port. The induced airflow containing harmful substances and malodorous components is introduced in the direction perpendicular to the reflector 4 attached at approximately 45 degrees. The introduced wind is strong near the fluidized bed and weak wind speed far away. The wind introduced into the fluidized bed cylinder 5 through the lower filter 6 becomes an air flow that induces internal circulation, and the catalyst 7 as a fluid medium also enters a flow state similar to the flow of the air flow, causing internal circulation flow. Hazardous substances and malodorous components in the air current are decomposed while fluidly contacting. The purified airflow is discharged to the outside through the upper filter 8 installed at the upper part.

  The fluid medium used was a polystyrene foam, and bamboo charcoal fine powder or porous silicate was used as the porous body. An example of using platinum nanocolloid as a water-soluble ceramic redox catalyst or oxidation promotion catalyst of inorganic oligomers such as silicic acid and phosphoric acid having antistatic effect as a catalyst will be described. In practice, it can be used for sterilization, sterilization, and infection prevention by coating an organic or inorganic antibacterial composition having an antibacterial effect against bacteria, molds, viruses, etc.

  The presence or absence of the antistatic effect of the catalyst as the fluidized medium of the present invention greatly affects the flow characteristics. Porous foams such as polystyrene, polyethylene, polylactic acid resin of vegetable resin, etc. are easily charged with static electricity, and catalysts that do not have antistatic effect can be used for long-term continuous operation. It is difficult to form and maintain a fluid state by adhering to the surface, but when a water-soluble ceramic redox catalyst of an inorganic oligomer such as silicic acid or phosphoric acid having an antistatic effect is coated, a smooth fluid state can be maintained.

  Between the motor fan 2 of the main body wind box and the fluidized bed cylinder 5, there is installed an apparatus 3 for dropping a solution containing a water-soluble ceramic redox catalyst solution for replenishment and colloidal particles of platinum ultrafine particles. By dropping 10% by weight with respect to the weight of the catalyst used as the fluidized medium, it is atomized by the air current and pushed into the fluidized bed cylinder 5. Since the inside of the fluidized bed is in contact with the catalyst as the fluidized medium, the air-conducting air is blown for about 2 hours, so that the solution containing the water-soluble ceramic redox catalyst solution and the colloidal particles of platinum ultrafine particles is dried and coated. Function can be restored.

The lower filter 6 of the cartridge cylinder is installed for the purpose of preventing the fall of the catalyst as a fluid medium in the fluidized bed and rectifying the wind strength, but if it is too fine and the resistance by the filter net increases, the wind pressure Decreases and the fluid state deteriorates. In the present catalyst, a size of 150 mesh is a preferable rectified air flow with little resistance.

The upper filter 8 of the cartridge cylinder is installed for the purpose of preventing the exfoliation of the catalyst as a fluid medium in the fluidized bed and the scattering of dust, etc., but if it is too fine and the resistance of the filter net increases, However, the moderately fine filter size has an effect of generating an appropriate resistance in the upper space and suppressing the flushing of the catalyst as a lightweight fluid medium. As a result of the flow experiment, the size of the upper filter which can use the catalyst as the flow medium of the present invention, suppress the flushing, and create a smooth internal circulation flow is 150 to 300 mesh.
Although the upper filter size was set to a 60 mesh size filter size, scattering could be prevented, but a flushing phenomenon occurred and a smooth flow state could not be maintained.

In the flow test, the carrier as a fluid medium is Sekisui Chemical's polystyrene foam beads “Eslen beads” HDMF (center diameter 1 mm, expansion ratio 40 times) and Hitachi Chemical polystyrene foam beads “high beads” HB-E (center diameter 2 mm, foam) A flow experiment was performed with Sekisui Kasei polystyrene and foamed polyethylene composite foam beads “Piocelene” POSP (center diameter 5 mm, expansion ratio 40 times). The air volume of the motor fan was 1.2 m ³ / min, the lower filter was 150 mesh, and the upper filter was 200 mesh mesh.

  As a result, both of them reach a fluidized state and constitute a fluidized bed, but it corresponds to the flow of the wind and becomes an internal circulation type fluidized state where the upper part and the lower part are interchanged while the carrier as the upper fluid medium flows. These were polystyrene beads having a center diameter of 1 mm and an expansion ratio of 40 times, and carriers having other particle diameters were in a bubbling flow state in which they were stirred by bubbles.

  An experimental example of the adsorption decomposition effect in a low temperature range using a catalyst as a fluid medium is shown below.

<Catalyst as fluid medium>
In this test, polystyrene beads having a center diameter of 1 mm and an expansion ratio of 40 times were used as a catalyst carrier as a fluid medium used. As the porous adsorbent, bamboo charcoal pulverized coal with an average specific surface area of 372 m ² / g crushed to an average particle size of 8 to 12 μm and porous silicate with an average particle size of 2.5 to 4 μm (Lionite SF of Lion Corporation) It was used. An acrylic acid copolymer emulsion was used as a binder, and 1 kg of polystyrene beads, 0.1 kg of binder and 0.2 kg of bamboo charcoal pulverized coal were mixed, dried and bonded at 40 degrees Celsius, and catalyst 1 was obtained. Further, as a water-soluble ceramic redox catalyst composed of silicic acid and phosphoric acid oligomer, the catalyst 1 was immersed in a ceramics D solution manufactured by New Ecomaterials and coated. The catalyst was made to have a weight ratio of 1% and then dried. Similarly, a polystyrene bead coated with a silicate lionite lyonite SF is impregnated with catalyst 3 and catalyst 3 is immersed in a ceramic D solution and coated to a weight ratio of 1%, and then dried. Catalyst 4 was obtained. Further, the Serafix D solution was put in a trigger type container, and about 300 ml was sprayed uniformly over 10 g of polystyrene beads in a mist state and dried to make catalyst 5. Furthermore, a 21-fold diluted solution of platinum nanocolloid particles (particle size 2.5 nm concentration 19.3 mmol) manufactured by Nano Cube Japan Co., Ltd. was added to 10 g of catalyst 5 in a trigger type container and stirred, and about 300 ml was evenly distributed. The catalyst 6 was sprayed in a mist and dried.

<Experimental example 1>
In Experimental Example 1, 3 liters of 22 ppm formaldehyde gas was placed in a 5 liter Tedlar bag, and 5 g each of Catalyst 1 and Catalyst 2 were placed in the bag, and the difference between absorption and decomposition due to elapsed time was measured. Table 1 shows the results of an experiment conducted at a test temperature of 23 ° C. and a humidity of 52%. Concentration measurement was performed using a formaldehyde detector tube with 100 ml each sucked.

  As shown in Table 1, the catalyst 2 in which the ceramics D solution is coated on bamboo charcoal has a higher deodorizing effect than the catalyst 1, and a synergistic effect of adding a water-soluble ceramic redox agent to bamboo charcoal appears.

<Experimental example 2>
In Experimental Example 2, 20 ml of acetic acid having a concentration of 0.01 mol was placed in a 5 liter Tedlar bag together with air, and 0.15 g of each of Catalyst 1 and Catalyst 2 was placed in the bag. The difference was measured. The results are shown in Table 2 (test temperature 21 ° C. and humidity 56%). Concentration measurement was performed with an acetic acid detector tube with 100 ml each sucked.

  Similar to Experimental Example 2, the catalyst 2 in which the ceramics D solution was coated on bamboo charcoal had a higher deodorizing effect than the catalyst 1, and a synergistic effect was obtained by adding a water-soluble ceramic redox catalyst to bamboo charcoal.

(Experimental example 3)
In Experimental Example 3, a comparison was made between bamboo charcoal fine powder and porous silicic acid used as a porous body, and a deodorization comparison of a catalyst in which a water-soluble ceramic redox agent was coated on the porous body. In the test, 5 g of the catalyst was filled at the bottom of a glass tube having a diameter of 5 cm and a length of 1 m, and the absorption / decomposition ability was measured by flowing a gas containing formalin from the bottom and circulating it. This test is a test assuming the contact flow state of the flow device. For the measurement, the concentration of formalin gas in the airflow according to the number of circulations was measured with a formaldehyde detector tube. 30 liters of air adjusted to a formalin concentration of 32 ppm to 34 ppm was passed through the glass tube. (Test temperature was 23 ° C. and humidity was 52%) Each time 100 ml of air flow gas was sucked and the gas concentration was measured. The gas concentration was a value obtained by multiplying the amount of gas sucked by a correction coefficient calculated. The experimental results are shown in Table-3.

  As a result of Experiment 1 to Experiment 3, any catalyst in which bamboo charcoal carries an inorganic oligomer redox agent such as silicic acid or phosphoric acid has a high deodorizing effect. Moreover, the synergistic effect was not recognized in the porous silicate which has the same adsorption effect as bamboo charcoal. This is because the combination of a porous material such as activated carbon or bamboo charcoal that has the function of an electric double layer and water-soluble ceramics that form an oxide oxide film with high ion conductivity has a function as a kind of electric double layer capacitor. Conceivable. Activated carbon as an electric double layer capacitor is said to have a capacitor of 50 F / g. By rapidly supplying electricity generated by friction as electrons for decomposition reaction, decomposition reaction is promoted, and ozone, heat, high power, etc. It is assumed that harmful components and odorous components can be decomposed efficiently at room temperature without using them.

(Experimental example 4)
In Experimental Example 4, a deodorizing test by circulating flow was performed using the catalyst 1 and the catalyst 2 in a deodorizing test using a small fluidized bed apparatus according to the present invention. Put 30 ppm and 35 ppm formaldehyde gas into a 2 m ³ Tedlar bag, put 20 grams of catalyst 1 into the fluidized bed of the apparatus, and circulate it at an air flow rate of 1 m ³ per minute. Measured.
Similarly, the results of the circulation test with the catalyst 2 added are shown in Table 4 (test temperature 23 ° C., humidity 52%), and it was proved that the cracking ability by contact of this flow apparatus was high.

In Experimental Example 5, the difference between absorption and decomposition due to the circulation flow was measured by putting 5 g of each of the catalyst 5 and the catalyst 6 in a 5 liter Tedlar bag together with air at an ammonia gas concentration of 24 ppm and putting them in the bag. The test results are shown in Table 5 (test temperature 23 ° C. and humidity 52%).
Concentration measurement was performed with an ammonia detector tube with 100 milliliters of suction.

水溶性セラミックス酸化還元剤のセラフイックス溶液はアンモニア臭除去に有効であるが、白金ナノコロイド触媒との相乗効果により強い脱臭効果が得られる。

A ceramic solution of a water-soluble ceramic redox agent is effective for removing ammonia odor, but a strong deodorizing effect is obtained by a synergistic effect with a platinum nanocolloid catalyst.

The fluidized bed air purifying device which is the main object of the present invention is an indoor air purifying device for general households, business facilities, hospitals, etc., but by removing the large harmful volatile gas for factories by examining the design conditions, etc. Can also be used.

Partial sectional view of the present invention

Explanation of symbols

1. Body box 1 Fan 3. 3. Supply ceramic dropping device 4. Slope wind reflection plate Cartridge type fluidized bed cylinder 6. 6. Air volume control filter 7. Catalyst as fluid medium Upper filter

Claims (6)

  A fluidized bed reaction apparatus comprising a granular foam made of polystyrene or polyethylene carrying a redox catalyst or a polylactic acid resin of a vegetable resin as a fluidized bed.   The granular foam according to claim 1 is formed by coating a water-soluble ceramic redox catalyst composed of silicic acid and phosphoric acid oligomer having an antistatic effect, or by previously coating a porous body having characteristics of an electric double layer, It is produced by coating a water-soluble ceramic redox catalyst consisting of silicic acid and phosphoric acid oligomer on it, or the granular foam is coated simultaneously with a water-soluble ceramic redox catalyst consisting of silicic acid and phosphoric acid oligomer and platinum ultrafine particles of 3 nm or less. A fluidized bed reactor characterized by comprising:   3. A fluidized bed reactor characterized in that the foam according to claim 1 or 2 has a specific gravity of 0.04 or less, an average diameter of 1 mm or more and a diameter of 5 mm or less.   2. A fluidized bed reactor according to claim 1, further comprising a water-soluble ceramic redox catalyst made of an oligomer such as silicic acid and phosphoric acid, and a replenishment dropping spray device for coating the ultrafine platinum particles.   2. The fluidized bed reactor according to claim 1, wherein the granular catalyst is packed in a cartridge-type catalyst tower that can be desorbed and exchanged, and a filter of 150 mesh or more and 300 mesh or less is attached to the upper and lower space end faces of the catalyst tower. A fluidized bed reactor.   The fluidized bed reactor according to claim 1, wherein a motor fan is attached to the wind box in a direction perpendicular to the catalyst tower, the blown wind is introduced into the fluidized bed by a wind reflector, and the velocity of the wind in the fluidized bed is reduced. A fluidized bed reactor characterized by creating a flow and causing an internal circulation in the fluidized bed.

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