JPS6155411B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a filter that removes odors, nitrogen dioxide (NO ₂ ), carbon monoxide (CO), etc. present in the air at room temperature in the presence of water vapor. The present invention provides a harmful gas removal filter that allows the configuration of each removal agent to be selected arbitrarily depending on the application, allows easy replacement of the removal agent, and has low pressure loss.

NO ₂ and CO are emitted by car engines, kerosene heaters, and other household heaters, so they can be used at expressway toll collection stations, underground parking lots, car tunnels with inadequate ventilation, and urban centers with heavy traffic. People working, living in, or passing through the area sometimes felt sick and complained of headaches. On the other hand, if a kerosene stove is burnt for a long time and there is insufficient ventilation indoors,
The concentration of CO and NO ₂ increased, eventually causing poisoning symptoms. As described above, NO ₂ and CO are harmful to the human body, and NO ₂ irritates the mucous membranes of the nose, eyes, etc., and may eventually cause diseases in the respiratory system. Furthermore, CO also impaired vision and mental function, and there was a risk that it would eventually lead to pulse failure and syncope accompanied by convulsions. For this reason, there is a strong desire to remove NO ₂ and CO that exist indoors, and the smell also makes people feel uncomfortable, so it has been desired to remove it.

Activated carbon has traditionally been used to remove NO ₂ present in the air, but this _activated carbon
The removal capacity is small and the product reaches the end of its service life quickly, and NO ₂ is reduced to NO at high temperatures, and the adsorbed NO ₂ can be desorbed depending on the operating conditions. The conventionally used mixture of alkali, powdered activated carbon, and cement agent is a dry absorbent in which the alkali in the composition reacts with NO ₂ to form salt, so it has a large removal capacity and has a lifespan 10 times longer than that of activated carbon. , reduction to NO,
No. ₂ was not attached or detached.

Furthermore, there are hopcalite catalysts and noble metal catalysts as catalysts for oxidizing CO to CO _2. Hopcalite catalysts are mixtures of 60% MnO ₂ and 40% CuO, or
It is a mixture of 50% MnO ₂ , 30% CuO, 15% CoO, and 5% Ag ₂ O, and although it exhibits activity even at room temperature, it has the disadvantage that its activity decreases in the presence of water vapor. Noble metal catalysts are made by supporting precious metals such as platinum or palladium on alumina or activated carbon carriers, and they exhibit their activity at relatively high temperatures (over 80°C), making them suitable for mixing and molding of alkali, powdered activated carbon, and cement materials. Catalysts on which one or more selected from the group of platinum, ruthenium, and rhodium and palladium were simultaneously supported, or on which palladium alone was supported, oxidized CO even at room temperature in the presence of water vapor.

Therefore, for removing NO ₂ at room temperature in the presence of water vapor, there is a kneaded molded product of alkali, powdered activated carbon, and cement, and for oxidizing CO to CO ₂ , a kneaded molded product of alkali, powdered activated carbon, and cement material is used. A catalyst in which one or more selected from the group of platinum, ruthenium, and rhodium and palladium are supported at the same time or palladium alone is optimal, and these kneaded and molded products and catalysts can be used as air conditioning filters, and Activated carbon is used for deodorization.

A filter for air conditioning is desired to have a low pressure loss and a high harmful gas removal rate, and the pressure loss increases in proportion to the thickness (layer height) of the filter and the square of the air flow rate passing through the filter layer. The removal rate increases as the thickness increases and the air flow rate decreases.
Therefore, efforts have been made to reduce the pressure loss and increase the removal rate by increasing the filter area as much as possible and slowing the air flow rate through it. Examples of this are honeycomb structures and structures in which the material is zigzag. However, the honeycomb type was difficult to manufacture and was prone to defects such as cracks, so it was difficult to establish manufacturing know-how, and the manufacturing equipment was large and expensive, making it difficult to manufacture. In the case of a structure in which the material is zigzag, it is a non-woven fabric type in which about 10 to 30 mesh pellets are sandwiched between polypropylene fibers, so it is only necessary to fold the non-woven fabric in a zigzag pattern, but it is also possible to use a zigzag-shaped non-woven fabric as a filter. There was a problem with the fixing method, and the disadvantage was that the oversurface area could not be made very large.

Furthermore, when using two or more types of harmful gas removers with different characteristics at the same time, conventionally, filters filled with only each remover were stacked one on top of the other, resulting in a problem of high pressure loss for the filter as a whole.
Furthermore, the method of filling the same filter with a mixture of harmful gas removing agents having different properties is also undesirable from the viewpoint of maintenance and inspection.

The present invention provides a filter that has a large overarea, allows the configuration of each remover to be arbitrarily selected depending on the application, allows easy replacement of the remover, and has low pressure loss. , NO ₂ , and CO at room temperature in the presence of water vapor, and the filling is detachable.

Hereinafter, one embodiment of the present invention will be described in detail about a harmful gas removal filter constructed of a nonwoven fabric type in which activated carbon, a CO oxidation catalyst, and an NO ₂ removal agent are individually sandwiched between two fibers. Fig. 1 shows an external view of the nonwoven fabric, Fig. 2 shows a cross-sectional view, and 1 shows activated carbon;
A kneaded molded product of alkali, powdered activated carbon, and cement material (NO ₂ removal agent), and a kneaded molded product of alkali, powdered activated carbon, and cement material are mixed with one or more selected from the group of platinum, ruthenium, and rhodium and palladium at the same time, or A gas removing agent consisting of a catalyst (CO oxidation catalyst) supporting only palladium, 2 is a polymeric fiber such as polypropylene, 3 is a nonwoven fabric, and this nonwoven fabric 3 has activated carbon and an NO ₂ removing agent between the polymeric fibers 2. , a CO oxidation catalyst filler is sandwiched between each independently. The nonwoven fabric 3 is manufactured by a manufacturing method using needle punching, a manufacturing method using heat fusion, or the like.

FIG. 3 shows the structure of an overlayer, in which the flat nonwoven fabric 3 shown in FIG. A nonwoven fabric 3' is attached around the periphery to form an overlayer. Note that 5 is a shielding plate and 6 is a protrusion. If the nonwoven fabric 3' is strong and will not be easily crushed by fingers, the skeleton 4 is unnecessary, and only one side of the bottom surface of the nonwoven fabric 3' may be covered with a metal or plastic surface. The skeleton 4 has a cylindrical structure and has dimensions that prevent air from leaking from the surrounding area when the nonwoven fabric 3' is attached around it. Further, one side of the bottom part is open so that air can freely enter and exit, and a shielding plate 5 is placed on the other side so that air cannot enter and exit. The side part fixes the nonwoven fabric, has a shape that does not allow air to freely enter and exit, and does not easily crush the nonwoven fabric with fingers, etc. when the nonwoven fabric is fixed, and the nonwoven fabric 3' and the skeleton 4 are fixed by heat fusion or the like. ing. The shape of the overlayer is not limited to a cylindrical shape, but also triangular prisms, quadrangular prisms, hexagonal prisms, polygonal prisms, cones, triangular pyramids, polygonal pyramids, and other shapes.

Figure 5 shows the flow of air in the superlayer, where 8 is an open part and 9 is a side part. Air is introduced from the open part 8 and exhausted from the side part 9, and vice versa. It is possible.

Figure 6 shows the air flow in the gas removal filter, where 10 is an overlayer, 11 is a fixed plate, and the overlayer 10 is detachably fixed to the fixed plate 11 to remove harmful gases. Form a filter. Air is introduced from the front surface of the fixed plate 11 and exhausted from the side surface of the overlayer 10 through the opening 8, and vice versa. The overlayer 10 is removably fixed to the fixing plate 11 by the projections 6 shown in FIG. The fixed plate 11 has an open part 8
There are exactly the same number of holes as there are 10 in the superlayer.

Figure 7 shows an example of the arrangement of activated carbon, NO ₂ removal agent, and CO oxidation catalyst in a harmful gas removal filter, where 12 is activated carbon, 13 is NO ₂ removal agent, and 1
4 is CO oxidation catalyst, activated carbon 12, NO ₂ removal agent 1
3. The superlayer consisting of CO oxidation catalyst 14 is fixed plate 1
1, and are arranged in an optimal configuration depending on the usage environment and application.

The molded mixture of alkali, powdered activated carbon, and cement material removes NO ₂ at room temperature, and its manufacturing method uses potassium carbonate (K ₂ CO ₃ ) as the alkali, calcium hydroxide [Ca(OH) ₂ ] as the cement material, and sintering as the cement material. Select gypsum (CaSO ₄ 1/2H ₂ O) and add potassium carbonate/calcium hydroxide/calcined gypsum/powdered activated carbon = 30/30/
A 20/20 (wt%) composition was mixed with 1.0 wt% sodium carboxymethylcellulose and water, dried, and classified into 10 to 20 meshes. The relationship between the space velocity and the NO ₂ removal rate of this kneaded molded product is as shown in Figure 8, and the reason why NO ₂ is removed through the kneaded molded product is because of the alkali and NO ₂ in the composition of the kneaded molded product. by reacting to form salts and absorbing NO ₂ .

2NO ₂ +K ₂ CO ₃ →KNO ₂ +KNO ₃ +CO ₂ 4NO ₂ +2Ca(OH) ₂ → Ca(NO ₂ ) ₂ +Ca(NO ₃ ) ₂ +2H ₂ O Conditions are NO ₂ 1.0ppm, temperature 30℃, relative humidity
It was set at 55%.

In addition, catalysts in which one or more selected from the group of platinum, ruthenium, and rhodium and palladium are simultaneously supported on a kneaded molded product of alkali, cement agent, and powdered activated carbon, or palladium alone can be used even under normal temperature and humid conditions.
CO is oxidized to CO ₂ , and the manufacturing method is to select potassium carbonate as the alkali and alumina cement as the cement agent, and add 0.5wt of sodium carboxymethyl cellulose to the composition of potassium carbonate/alumina cement/powdered activated carbon = 10/60/30 (wt%). % and water were added, kneaded and molded, dried and classified into 10 to 20 meshes. After optimizing the procedure so that 0.3wt% each of platinum and palladium as precious metals were simultaneously supported on the above kneaded and molded product, the mixture was reduced with sodium borohydride, thoroughly washed with water, dried at approximately 100°C, and then catalyzed. He said. The relationship between catalyst temperature and CO conversion rate is shown in Figure 9. The catalyst oxidizes CO and converts it into CO ₂ .

2CO＋O ₂ →2CO _2The conditions were CO100ppm, SV24000/hour, and absolute humidity 0.0145Kg/Kg dry air.

To evaluate the effectiveness, we made a prototype filter, installed it in the airflow section of a blower, and measured the indoor concentration attenuation. The filter is composed of a nonwoven fabric in which activated carbon, NO ₂ removing agent, and CO oxidation catalyst are individually filled between polypropylene fibers, and the packing density is set to 0.04 g per unit area (cm ² ) of polypropylene. This is what I did. This nonwoven fabric was processed and molded into a cylindrical shape as shown in FIG. 5 to fabricate a filter. The inner diameter of the open part of the filter was 15 mm, and the length of the side part in the height direction was 30 mm. This filter was fixed to a fixed plate (40 cm x 40 cm) as shown in Figure 6 to form the final filter. The harmful gas removal filters were made by uniformly dispersing individual filters such that the activated carbon filter was 30%, the NO ₂ removal agent filter was 30%, and the CO oxidation catalyst filter was 40%.

Blow capacity of harmful gas removal filter: 4.0Nm ³ /
Installed in a commercially available air purifier that has the air blowing capacity of
This air purifier was operated in a 6-tatami room (internal volume: 30 m ³ ) with a ventilation frequency of 0.5 times/hour, and the concentration decay of NO ₂ and CO in the room was continuously measured. Measurements were made using a chemiluminescent low-concentration NO _x analyzer for NO ₂ and a non-dispersive infrared low-concentration CO analyzer for CO.
The indoor temperature was 25°C and the relative humidity was 62%. NO ₂ and CO were injected into the room in advance using a commercially available standard gas cylinder, and the NO ₂ concentration in the room was 1.00 ppm.
The gas amount was adjusted so that the CO concentration was 20 ppm at the same time. The indoor concentration is NO ₂ 1.00ppm at the same time,
When CO reached 20 ppm, gas supply was stopped and the air purifier was operated. The concentration distribution in the room is uniform because NO ₂ and CO are introduced from standard gas cylinders and diffused using a blower. The indoor concentration was measured in the center of the room, which would be near the mouth of a person when standing, and the air purifier was installed in the center of the wall. Fig. 10 shows the NO ₂ concentration decay, and Fig. 11 shows the CO concentration decay, which shows the effect of the NO ₂ remover and CO oxidation catalyst. Note that curve A
has the filter in this example, B
C has a multilayer filter, and C has no filter.

The pressure loss of the final filter was as shown in FIG. Non-woven fabric filled with _NO2 remover, CO
The effect of using nonwoven fabrics filled with oxidation catalysts stacked in the direction of air flow is as shown in Figures 10 to _12. The structure of this filter is as follows:
A stacked nonwoven fabric in which a CO oxidation catalyst is individually packed between polypropylene fibers at a packing density of 0.04 g/cm ² is used, and is installed perpendicular to the air flow, and here it is a laminated type.

As described above, the present invention makes it easy to remove odors, nitrogen dioxide, and carbon monoxide, and each remover can be replaced without removing other removers, and further,
Since the surface area of the nonwoven fabric can be easily increased, it is of great industrial value to provide a filter that exhibits excellent effects such as not significantly reducing the flow rate of gas passing through it.

[Brief explanation of the drawing]

Figure 1 is an external view of the nonwoven fabric, Figure 2 is a cross-sectional view of the same,
Figure 3 is a configuration diagram of the overlayer, Figure 4 is a perspective view of the skeleton, Figure 5 is a completed diagram of the overlayer, Figure 6 is a completed view of the harmful gas removal filter, and Figure 7 is a diagram of the harmful gas removal agent. Layout diagram, Figure 8 is the SV characteristic diagram of the NO ₂ remover,
Figure 9 is a temperature characteristic diagram of the CO oxidation catalyst, and Figure 10 is
FIG. 11 is a NO ₂ concentration decay diagram, FIG. 11 is a CO concentration decay diagram, and FIG. 12 is a pressure loss characteristic diagram.

Claims (1)

[Claims] 1. A harmful gas removal filter in which activated carbon, a nitrogen dioxide removing agent, a carbon monoxide removing agent, etc. are each filled in a nonwoven fabric, and these nonwoven fabrics are each removably attached to holes in a fixing plate provided in an overlayer. .