JP4309162B2 - Carbon monoxide removal unit, carbon monoxide removal method, air cleaning device, and carbon monoxide removal catalyst composition - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a carbon monoxide removal unit, a carbon monoxide removal method, an air cleaning device, and a carbon monoxide removal catalyst composition for removing carbon monoxide-containing gas with a small energy consumption.
[0002]
[Prior art]
It is well known that carbon monoxide is harmful to the human body, and various methods for efficiently removing carbon monoxide contained in automobile exhaust gas and the like have been studied. In addition, carbon monoxide generated when producing hydrogen for use in fuel cells impedes fuel cell power generation, so it is important how efficiently carbon monoxide is removed even in the technical field related to fuel cells. Technical issue.
Currently, active research is being conducted as a method for removing carbon monoxide using a catalyst composition containing a transition metal having carbon monoxide oxidizing ability, and oxidizing carbon monoxide by catalytic reaction to carbon dioxide. (See, for example, Patent Document 1 below).
[0003]
[Patent Document 1]
Japanese Patent No. 3251809 [0004]
[Problems to be solved by the invention]
However, in order to oxidize carbon monoxide and convert it to carbon dioxide by catalytic reaction, it is usually necessary to raise the reaction temperature to 200 ° C. or higher, and therefore further investigation is required from the viewpoint of energy saving.
Therefore, the present invention provides a carbon monoxide removal unit, a carbon monoxide removal method, an air purifier, and a carbon monoxide removal catalyst composition for removing carbon monoxide-containing gas with a small energy consumption. With the goal.
[0005]
[Means for Solving the Problems]
The carbon monoxide removal unit of the present invention made in view of the above points, as described in claim 1, is a high heat in which a catalyst composition containing a transition metal having a carbon monoxide oxidation ability is supported at the subsequent stage of the dehumidifying means. After carbon monoxide removing means composed of a carrier made of a conductive material is disposed , and further heating means is disposed between the dehumidifying means and the carbon monoxide removing means, and after dehumidifying the gas containing carbon monoxide Further, the carbon monoxide is removed after heating, and the carbon monoxide oxidizing ability is regenerated by introducing hot air to the carbon monoxide removing means and heating it at predetermined intervals. characterized in that the.
Also, the carbon monoxide removing unit according to claim 2, wherein, in the carbon monoxide removing unit according to claim 1, wherein, dehumidifying means absorbs moisture and gas from which carbon monoxide has been removed by being guided to the carbon monoxide removing unit The dehumidifying means is regenerated by releasing moisture from the dehumidifying means into the gas.
Further, the carbon monoxide removal unit according to claim 3, wherein, in the carbon monoxide removing unit according to claim 1 or 2, characterized in that it constitutes the dehumidifying means by desiccant.
Also, the carbon monoxide removing unit according to claim 4, wherein, in the carbon monoxide removal unit according to any one of claims 1 to 3, a transition metal having a carbon monoxide oxidizing ability of ruthenium, rhodium, palladium, platinum It is at least one selected from.
Moreover, the carbon monoxide removal unit according to claim 5 is the carbon monoxide removal unit according to any one of claims 1 to 3, wherein the catalyst composition includes a transition metal having a carbon monoxide oxidation ability, chromium, It consists of at least one transition metal selected from iron, cobalt, and copper and a complex oxide mainly composed of manganese .
Also, the carbon monoxide removing method of the present invention, as claimed in claim 6, characterized in that for removing carbon monoxide using a carbon monoxide removal unit according to any one of claims 1 to 5 .
Also, the air cleaning apparatus of the present invention, as claimed in claim 7, and characterized by including carbon monoxide removal unit according to any one of claims 1 to 5.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, if necessary, carbon monoxide is removed by introducing a gas containing carbon monoxide to the dehumidifying means and dehumidifying it, and then introducing it to the carbon monoxide removing means. Conventionally, in order to remove carbon monoxide by oxidizing it to carbon dioxide by catalytic reaction using a catalyst composition containing a transition metal having carbon monoxide oxidizing ability, the reaction temperature is increased to 200 ° C. or higher. Although it was necessary, according to the present invention, carbon monoxide can be efficiently removed by promoting the catalytic reaction at a lower temperature by dehumidifying the gas containing carbon monoxide in advance. Energy saving can be achieved.
[0007]
The dehumidifying means in the present invention is composed of, for example, a desiccant (dehumidifying agent such as silica gel, activated carbon or zeolite).
[0008]
The carbon monoxide removing means in the present invention is constituted by, for example, a support on which a catalyst composition containing a transition metal having carbon monoxide oxidizing ability is supported. Here, as the transition metal having carbon monoxide oxidizing ability, ruthenium, rhodium, palladium, platinum and the like are preferably used. The catalyst composition may be of any composition as long as it contains a transition metal having carbon monoxide oxidizing ability, and among them, a transition metal having carbon monoxide oxidizing ability, chromium, iron, A compound composed of at least one transition metal selected from cobalt and copper and a complex oxide mainly composed of manganese is composed of a conventionally known transition metal capable of oxidizing carbon monoxide and iron oxide or alumina. Carbon monoxide can be efficiently removed at a lower temperature than that of carbon dioxide, and harmful gases such as acetaldehyde and ammonia can also be efficiently removed.
[0009]
A catalyst composition comprising a transition metal having carbon monoxide oxidizing ability, at least one transition metal selected from chromium, iron, cobalt, and copper and a composite oxide mainly composed of manganese is, for example, first chromium, iron A pH adjuster such as aqueous ammonia is added to an aqueous solution in which at least one transition metal salt selected from cobalt, copper (nitrate, sulfate, etc.) and manganese salt (nitrate, sulfate, etc.) is dissolved. These hydroxides precipitated in an aqueous solution were calcined in air at 200 ° C. to 300 ° C. to remove impurities, and then these composite oxides were obtained. An aqueous solution in which a transition metal salt (nitrate, sulfate, etc.) capable of oxidizing carbon oxide is dispersed in this composite oxide, and then calcined in air at 200 ° C. to 300 ° C. to remove impurities. Letting It can be prepared. The catalyst composition thus prepared is dispersed in water together with, for example, a binder such as silica sol and uniformly mixed to form a slurry, and this is applied to a support such as a ceramic honeycomb filter. Then, it is set as a carbon monoxide removal means by baking at 200 to 300 degreeC in the air. Ceramic support is excellent in supporting adhesion of slurries, so it can support a large amount of catalyst composition even with a small amount of binder, there is less concern about corrosion due to harmful gas components, and the price is low. It is convenient in terms of
In addition, a solution in which an aqueous solution in which a transition metal salt having carbon monoxide oxidizing ability is dissolved is dispersed in the above composite oxide, for example, is mixed with a binder such as silica sol to obtain a slurry-like material. May be applied to a carrier such as a honeycomb filter made of ceramics and then fired at 200 ° C. to 300 ° C. in air to remove impurities and serve as carbon monoxide removing means.
[0010]
In the carbon monoxide removal unit of the present invention, when the carbon monoxide removal means is constituted by a carrier carrying a catalyst composition containing a transition metal having carbon monoxide oxidation ability, the dehumidification means and the carbon monoxide removal means It is desirable that a heating means is further provided between them to dehumidify the gas containing carbon monoxide, and then further heated before removing the carbon monoxide. By adopting such an embodiment, if a gas containing high-temperature carbon monoxide is brought into contact with the catalyst composition, carbon monoxide can be effectively oxidized to carbon dioxide. Can be further increased. Further, since the gas from which the carbon monoxide discharged from the carbon monoxide removing means is removed is in a high temperature and dehumidified state, if the gas is guided to the dehumidifying means that has absorbed moisture, the moisture from the dehumidifying means There is also an advantage that the dehumidifying means can be regenerated because it is released into the gas.
[0011]
When the carbon monoxide removing means is constituted by a carrier on which a catalyst composition containing a transition metal having carbon monoxide oxidizing ability is supported, moisture adheres to the surface of the catalyst composition after a long period of use, and the adhered moisture May become a catalyst poison and reduce the carbon monoxide oxidizing ability of the catalyst composition. In order to avoid such a phenomenon as much as possible, in the carbon monoxide removal unit of the present invention, preferably, a heating means is further provided between the dehumidification means and the carbon monoxide removal means to dehumidify the gas containing carbon monoxide. Then, after further heating, carbon monoxide is removed. Nevertheless, it is not always easy to completely deny the possibility of such a phenomenon. Therefore, it is desirable to regenerate the carbon monoxide oxidizing ability of the catalyst composition by heating the carbon monoxide removing means every predetermined time to evaporate and remove the water adhering to the surface of the catalyst composition. As a method for heating the carbon monoxide removing means, for example, there is a method in which hot air is generated by a heating means disposed in front of the carbon monoxide removing means and the generated hot air is guided to the carbon monoxide removing means. For example, once the carbon monoxide removing means is heated to 200 ° C. or higher (desirably about 250 ° C.) once a day, the carbon monoxide oxidizing ability of the catalyst composition can be effectively regenerated. . At this time, if the carrier for supporting the catalyst composition is made of a highly heat conductive material such as aluminum or stainless steel, the carbon monoxide removing means can quickly increase the temperature. Performance can be quickly recovered with less energy consumption.
[0012]
In addition, you may make it guide | induced to a dehumidification means, after purifying the gas containing carbon monoxide by arrange | positioning an air purifying means in the front | former stage of a dehumidification means. Further, a cooling unit may be disposed in front of the dehumidifying unit, so that the relative humidity of the gas containing carbon monoxide is once increased and then guided to the dehumidifying unit.
[0013]
The use of the carbon monoxide removal unit of the present invention is not particularly limited. For example, the carbon monoxide removal unit can be used by being incorporated in an air purifier (such as a smoke counter) or by being incorporated in a fuel cell manufacturing apparatus. You can also.
[0014]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is limited to the following description and is not interpreted at all.
[0015]
Example 1: Preparation of carbon monoxide removing means 1
Ammonia water is dropped into an aqueous solution in which cobalt nitrate and manganese nitrate are dissolved (cobalt and manganese are adjusted so as to be contained at an atomic ratio of 1: 1), and a hydroxide of cobalt and manganese is precipitated, filtered, and filtered. It was collected. The collected precipitate was baked at 250 ° C. in the air to remove impurities, thereby obtaining a complex oxide of cobalt and manganese. Next, an aqueous solution in which platinum nitrate was dissolved was dispersed in this composite oxide, and this was uniformly mixed with silica sol to obtain a slurry. A ceramic honeycomb filter having a diameter of 20 mm and a length of 40 mm is immersed in this slurry, and then lifted and fired at 250 ° C. in air to remove impurities, and the platinum content is 1% by weight. A carbon monoxide removing means carrying 1.1 g of the catalyst composition was prepared.
The basic characteristics of this carbon monoxide removal means (Pt-CoMn) are shown in FIG. The basic characteristic is that a sample (carbon monoxide removing means) is inserted into a quartz reaction tube having an inner diameter of 20 mm so that it can be heated by a heater from the outside, and the relative humidity is 70% with carbon monoxide at a concentration of 20 ppm. Evaluation was performed by conducting experiments under various temperature conditions in which air was fed and contacted with the catalyst composition to examine the carbon monoxide removal rate. As is apparent from FIG. 1, this carbon monoxide removing means is a carbon monoxide removing means (Au—Fe ₂ O ₃ , Pt—Al) prepared in the same manner using a conventionally known catalyst composition. ₂ O ₃ ) was found to have excellent carbon monoxide removal rate even at lower temperatures.
[0016]
Example 2: Preparation of carbon monoxide removal means 2
In place of platinum nitrate in Example 1, palladium nitrate was used, and in the same manner as in Example 1, a carbon monoxide removing means carrying a catalyst composition having a palladium content of 1% by weight was prepared.
The basic characteristics of this carbon monoxide removal means are shown in FIG. As apparent from FIG. 2, it was found that this carbon monoxide removing means has an excellent carbon monoxide removal rate even at a low temperature. Moreover, the relationship between the carbon monoxide removal rate and the relative humidity at a space velocity (SV) of 54,000 h ⁻¹ of this carbon monoxide removing means is shown in FIGS. As apparent from FIGS. 3 to 5, this carbon monoxide removal means exhibits an excellent carbon monoxide removal rate as the relative humidity decreases, and even when the reaction temperature is 50 ° C. at a relative humidity of 15%, It was found that the carbon monoxide removal rate was 60% or more (FIG. 5).
[0017]
Example 3: Preparation of carbon monoxide removal means 3
In place of the ceramic honeycomb filter in Example 1, an aluminum honeycomb filter was used, and in the same manner as in Example 1, carbon monoxide removing means in which the carrier was made of a highly thermally conductive material was prepared.
[0018]
Example 4: Carbon monoxide removal unit The carbon monoxide removal unit A, whose schematic perspective cross-sectional view is shown in FIG. 6, includes a dehumidifying means B and a heating means C, for example, the carbon monoxide removing means D created in Example 1. Is the basic configuration.
A schematic perspective view of the dehumidifying means B is shown in FIG. The dehumidifying means B is a desiccant rotor in which inorganic fibers such as ceramic fibers and glass fibers, a flat paper 111 made by mixing these inorganic fibers and pulp, and corrugated paper 112 are laminated. Or formed into a disk shape and supported on a surface by a dehumidifying agent such as silica gel, activated carbon or zeolite.
The dehumidifying means B has a large number of small through holes 113 in the direction of the arrow in the figure and can be ventilated. When the gas containing carbon monoxide has a relatively higher humidity than this, the dehumidifying means B is small. When the gas passes through the holes, the dehumidifying agent absorbs moisture contained in the gas so that the dehumidified gas is guided to the heating means C. The heating means C is a heater, and the gas containing carbon monoxide is further heated after being dehumidified by the dehumidifying means B and the heating means C, and is guided to the carbon monoxide removing means D created in Example 1 for efficient operation. Carbon monoxide is removed.
In this carbon monoxide removal unit A, the gas from which the carbon monoxide discharged from the carbon monoxide removal means D is removed is in a high temperature and dehumidified state, so that the humidity is higher than that of the dehumidification means B that has absorbed moisture. Since the gas is relatively low, if the gas is guided to the dehumidifying means B that has absorbed moisture, the moisture is released to the gas when the gas passes through the small through holes, thereby regenerating the dehumidifying means B. be able to.
[0019]
Example 5: Air purifier (smoke counter 1)
FIG. 8 shows a schematic perspective view thereof, and FIG. 9 shows a schematic sectional view thereof. The smoke counter includes a main body 2 surrounded by an outer frame 1, a table 3 provided on the upper portion of the main body 2, a suction port 4 provided substantially at the center of the table 3, and a grill around the suction port 4. A suction grill 14 provided with a frame 13 and having a punching metal-like hole placed on the grill frame 13, a human sensor 28 for detecting a person provided by projecting from the suction grill 14, and the suction opening 4 on the downstream side, a dust collecting part 17 composed of a pre-filter 15 that collects dust that has passed through the suction grille 14, a dust collecting filter 16 that collects fine dust (for example, a HEPA filter), and a deodorizing filter that removes odors. 18 is provided, and further on the downstream side, a bottom plate 5 that partitions the inside of the main body 2, a motor base 7 provided on the bottom plate 5, and a motor 8 provided on both shafts on the motor base 7. The blower 10 comprised with the blade | wing 9 covered with 6 is mounted | worn, the edge part by the side of the blowing of the said casing 6 is being fixed to the baseplate 5, and the structure which produces the flow of air downstream from the suction inlet 4 It has become.
Further, a carbon monoxide removal unit 19 of Example 4 having a main body leg 11 having a caster 12 that can be easily moved and an exhaust port 29 communicating with an end portion on the blowing side of the casing 6 is provided at the bottom of the main body. ing.
Further, a control circuit unit 21 connected to a power cord 20 that supplies power is provided inside the main body 2, and an operation unit 27 that switches operation is provided on a side surface of the main body 2.
With the above configuration, when a smoker approaches to smoke a cigarette, the human sensor 28 detects this, and the motor 8 is energized by the control circuit unit 21 to operate the blower 10 and the inside of the main body 2 becomes negative pressure. Smoke components generated by smokers igniting and smoking cigarettes and dust contained in the air are sucked into the main body 2 from the punching metal-like holes of the suction grille 14 provided in the suction port 4, Relatively large dust is removed by the pre-filter 15, and relatively small dust that has passed through the pre-filter 15 is removed to fine dust by the dust collection filter 16.
The odor in the air is adsorbed by the deodorizing filter 18, and the dust and deodorized air passes through the casing 6 and the blades 9 of the blower 10, removes carbon monoxide in the carbon monoxide removal unit 19, and exhausts the air. It is discharged from the mouth 29 to the surroundings. Further, when the smoker finishes smoking and leaves the place, the human sensor 28 detects this, and after that, the remaining operation is performed for about 5 minutes (the time when the cigarette is burnt out) and stopped.
In this case, the human sensor 28 detects the person and operates. However, the operation is the same even if the operation switch of the operation part is turned ON.
The carbon monoxide removal unit 19 also removes harmful gases such as acetaldehyde and ammonia in addition to carbon monoxide, thereby contributing to further purification of indoor air.
In the smoke counter, the carbon monoxide removal unit 19 is provided on the downstream side of the blower 10, but the effect can be obtained even if provided on the upstream side of the blower 10 (for example, between the dust collection filter 16 and the blower 10). Will not change.
[0020]
Example 6: Air purifier (smoke counter 2)
FIG. 10 shows a schematic cross-sectional view thereof. The smoke counter is provided with an exhaust intake port 30 for taking in a part of exhaust air (for example, 1 m ³ / min) at an end of the casing 6 on the blow-out side, and further on the downstream side is included in the exhausted air. A carbon monoxide removal unit 19 for removing carbon oxide in Example 4 is provided at the bottom of the main body. The odor in the air is adsorbed by the deodorizing filter 18, and the purified air passes through the casing 6 and the blade 9 of the blower 10 and is exhausted to the outside through the exhaust port 29, but a part of the exhaust (for example, 1 m) ³ / min) is taken into the carbon monoxide removal unit 19 from the exhaust intake port 30 to remove the carbon monoxide and discharged from the exhaust port 29 to the surroundings. Thus, even in a sealed smoking room without ventilation, 1 m ³ / min of air purified by the carbon monoxide removal unit 19 circulates, so that the carbon monoxide contained in the tobacco is at a certain level concentration ( In addition to being able to suppress the building management method to a standard value of 10 ppm or less, harmful gases such as acetaldehyde and ammonia are also removed, thereby further purifying indoor air. Other configurations are the same as those of the smoke counter shown in the fifth embodiment.
[0021]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the carbon monoxide removal unit, the carbon monoxide removal method, the air purifier, and the carbon monoxide removal catalyst composition for removing this from the gas containing carbon monoxide with little energy consumption are provided. The
[Brief description of the drawings]
FIG. 1 is a graph showing basic characteristics of a carbon monoxide removing unit of Example 1. FIG.
FIG. 2 is a graph showing basic characteristics of a carbon monoxide removing unit of Example 2.
FIG. 3 is a graph showing a relationship between a carbon monoxide removal rate of a carbon monoxide removal unit of Example 2 and relative humidity (part 1);
FIG. 4 (No. 2)
FIG. 5 (No. 3)
6 is a schematic perspective cross-sectional view of a carbon monoxide removal unit of Embodiment 4. FIG.
7 is a schematic perspective view of dehumidifying means used in the carbon monoxide removing unit of Embodiment 4. FIG.
8 is a schematic perspective view of a smoke filter according to Embodiment 5. FIG.
FIG. 9 is a schematic sectional view of the same.
10 is a schematic cross-sectional view of a smoke smoking filter of Example 6. FIG.
[Explanation of symbols]
A Carbon monoxide removing unit B Dehumidifying means C Heating means D Carbon monoxide removing means 111 Plane paper 112 Corrugated paper 113 Small through hole

Claims (7)

After the dehumidifying means, carbon monoxide removing means composed of a support made of a high thermal conductivity material carrying a catalyst composition containing a transition metal having carbon monoxide oxidizing ability is arranged , and the dehumidifying means and monoxide are disposed. A heating means is further arranged between the carbon removing means, and after dehumidifying the gas containing carbon monoxide, the heating is further performed to remove the carbon monoxide, and the hot air is led to the carbon monoxide removing means. The carbon monoxide removing unit is characterized in that the carbon monoxide oxidizing ability of the catalyst composition is regenerated by heating it at predetermined intervals . It is characterized in that the gas from which carbon monoxide has been removed is guided to the dehumidifying means that has absorbed moisture by being guided to the carbon monoxide removing means, and the dehumidifying means is regenerated by releasing moisture from the dehumidifying means to the gas. The carbon monoxide removal unit according to claim 1 . 3. The carbon monoxide removing unit according to claim 1, wherein the dehumidifying means is constituted by a desiccant . The carbon monoxide removing unit according to any one of claims 1 to 3, wherein the transition metal having carbon monoxide oxidizing ability is at least one selected from ruthenium, rhodium, palladium and platinum. The catalyst composition comprises a transition metal having an ability to oxidize carbon monoxide, a composite oxide mainly composed of manganese and at least one transition metal selected from chromium, iron, cobalt, and copper. The carbon monoxide removal unit according to any one of 1 to 3 . A carbon monoxide removal method comprising removing carbon monoxide using the carbon monoxide removal unit according to any one of claims 1 to 5 . An air purifier comprising the carbon monoxide removing unit according to any one of claims 1 to 5 .

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