JP3254739B2 - Air purification method and air purification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifying method and an air purifying method for purifying odors generated in homes and offices, for example, odors of toilets, pets, cigarettes, cooking odors, body odors, etc. using a catalyst and an adsorbent. It concerns the device.

[0002]

2. Description of the Related Art The odorous components generated in homes and offices are composed of nitrogen compounds (ammonia, amines, indole,
Skatles, etc.), sulfur compounds (hydrogen sulfide, methyl mercaptan, methyl sulfide, methyl disulfide, etc.), aldehydes (formaldehyde, acetaldehyde, etc.), lower fatty acids (acetic acid, propionic acid, normal butyric acid, normal valeric acid, isokichi) And a wide variety of compounds such as ketones / alcohols and aromatic compounds.

Conventionally, as a method for removing such malodor, a method of chemically reacting a malodorous substance with a chemical, a method of masking a malodorous substance with an aromatic agent, a method of adsorbing a malodorous substance with activated carbon or zeolite, and the like, There has been a method using a combination of the above methods.

[0004] Among the various methods described above, activated carbon is extremely excellent in adsorption speed and adsorption capacity for many substances, and is the most commonly used deodorant in air purifiers. However, activated carbon also has a low adsorption capacity for low-boiling nitrogen compounds such as ammonia and methylamine, which are one of the components having strong odors, and low-boiling aldehydes such as formalin and acetaldehyde.

[0005] Therefore, deodorants obtained by impregnating chemicals with activated carbon have come to be used. However, even in the impregnated carbon, the capacities of the chemical adsorption of the lower nitrogen compound and the lower aldehydes with the impregnated chemicals and the physical adsorption of the high-boiling compounds are limited. In other words, the life of the deodorant using impregnated carbon is usually several months to half a year, and at most one year at the maximum, and there is a drawback that frequent replacement is troublesome and expensive.

[0006] As a deodorizing method that greatly reduces the frequency of such cumbersome operations or eliminates the necessity of such operations, a semiconductor such as titanium oxide is irradiated with ultraviolet rays, and the semiconductors excited thereby oxidize and decompose organic substances. Attempts have been made to use photocatalysts that emit light.

[0007]

According to such a method for deodorizing using a photocatalyst, acetaldehydes and other malodorous substances which have been difficult to deodorize with activated carbon can be effectively deodorized, and their performance can be maintained for a long time. It is possible to maintain

[0008] However, bad odors generated in homes and offices are caused by smoking of cigarettes with gas components and polymer substances (alkaloids such as nicotine, etc.) contained in cooking smoke.
Phenols and hydrocarbons). Many of these polymeric substances have a weak odor,
It attaches to and covers the semiconductor surface that causes a photocatalytic reaction. Because of this, ultraviolet light did not reach the catalyst,
The catalyst becomes less susceptible to energy, and the photocatalytic reaction is reduced to cause reaction deterioration.

In an adsorbent such as activated carbon, the adsorption speed is high when the odor gas concentration is high, but the adsorption speed is low when the gas concentration is low. On the other hand, the reaction rate at a low concentration of the photocatalyst is equal to or faster than the adsorption rate of the adsorbent, but the reaction at a high concentration is slower than the adsorption rate of the adsorbent.

The present invention has such a conventional method.
That issues a intended to solve, and to provide an air cleaning apparatus for deodorizing automatically efficiently as the first object.

[0011]

First means of the present invention for achieving the Means for Solving the Problems] The first object is achieved by a gas sensor for detecting a gas concentration in air, the adsorbent layer passing air containing odorous gases and A photocatalyst layer, flow path switching means for switching the air containing the odor gas to the adsorbent layer and the photocatalyst layer by detecting the odor gas by the gas sensor, and the flow path after a time proportional to the magnitude of the initial output of the gas sensor. The air purifying apparatus has a switching timer for switching the switching means.

[0012]

SUMMARY OF] The onset Ming first means, one that has to switch from the adsorbent layer after proportional to the magnitude time of the initial output of the gas sensor to the photocatalyst layer, deodorized automatically efficiently odorous gas Things.

[0013]

BRIEF DESCRIPTION The first exemplary embodiment of the present invention with reference to Reference Example 1 FIGS. FIG. 1 shows an experimental apparatus, in which 1 is a glass box having a volume of 1 m ³ , a door 2 and a handle 3 for the door 2.
It has. 4.5 and 5 are a fan and a motor for uniformly stirring the gas and smoke in the box 1. 6 is a rubber stopper for sampling the gas in the box 1. In the box 1, an adsorbent air purifying device 7 having an adsorbent layer, a dust collecting filter, and a blower, and a photocatalytic air purifying device 9 having a photocatalytic layer, an ultraviolet lamp provided opposite thereto, and a blower are provided. Is installed. Reference numeral 8 denotes an on / off switch of a blower of the adsorbent air purifying device 7, and reference numerals 10 and 11 denote switches of an ultraviolet lamp / blower of the photocatalytic air purifying device 9. In the box 1, a plate 13 for burning the tobacco 12 naturally is placed.

The adsorbent of the adsorbent air purifying device 7 includes:
Adsorbents with excellent odor and air pollutant adsorption capacity, such as porous minerals such as activated carbon, zeolite, silica gel, and sepiolite, and those impregnated with chemicals and plant essential oils are used. Here, 170 g of coconut shell activated carbon impregnated with 4% by weight of aniline and 70 g of coconut shell activated carbon impregnated with 30% by weight of phosphoric acid are used in order to purify the combustion gas and odor of tobacco. The specific surface area of the coconut shell activated carbon was about 1000 m ² / g, and the particle size of the adsorbent was 6 mesh to 12 mesh. The dust collection filter is provided on the windward side of the adsorbent layer. Here, electret-treated polypropylene is used. The air volume of the blower of the adsorbent air cleaning device 7 is about 2.5 m ³ / min.

As the photocatalyst layer of the photocatalyst air cleaning device 9, a semiconductor material excited by ultraviolet rays such as titanium oxide, zinc oxide and tungsten oxide is used alone or in combination. Here, an anatase type titanium oxide coated on a sheet made of ceramic fiber is used. The area of the catalyst layer is 1200 cm ² . On the other hand, the ultraviolet lamp facing the photocatalytic layer may be either a low-pressure mercury lamp or a high-pressure mercury lamp as long as it emits light having a wavelength having energy enough to excite the semiconductor.
Here, three germicidal lamps with power consumption of 15 W are used.
The air volume of the blower of the photocatalyst air cleaning device 9 is about 1.2 m ³ /
Minutes.

FIG. 2 shows a flow in an experiment using the apparatus shown in FIG. 1, and FIG. 3 shows a time change of the gas concentration in the box 1. For the measurement of the gas concentration, the air in the box 1 is sucked from the rubber stopper 6 and one is FID (flame ionization detect
r) Gas chromatograph with
The total area of the test was evaluated. The other was to evaluate the ammonia concentration using a gas detector tube. The operation of this embodiment is performed as follows.

The switches 8, 10 and 11 of the apparatus shown in FIG. 1 are all turned off, the door 2 is opened, one lit cigarette 13 is placed on the plate 13 in the box 1, and the door 2 is closed. Next, the power of the fan 4 is turned on, the air in the box 1 is stirred, and the cigarette 13
And uniformly disperse the smoke and odor therein. When all of the tobacco 13 has burned, the initial value C
Measure 0. Immediately after the initial value measurement, the switch 8 of the blower of the adsorbent air cleaning device 7 is turned on. In this case, it is assumed that the adsorbent air cleaning device 7 contains a new adsorbent. Thereafter, the gas concentration C is measured every 5 minutes. C / C0 was calculated from the gas concentration C, and when the area change of the FID was observed, it attenuated with time as shown in FIG. Further, the concentration of ammonia attenuated as shown in FIG. At about 16 minutes, about 20 minutes after the change in each concentration became small, the switch 8 of the blower of the adsorbent air cleaning device 7 was turned off, and at the same time, the ultraviolet light switch 10 of the photocatalytic air cleaning device 9 was turned on. . After 1 minute in this state, switch 1 on the blower
1 and then the gas concentration was measured every 5 minutes. As a result, the change in the area of the FID attenuated with time as 17 and the ammonia concentration attenuated as 18 with time.
When the respective concentrations became lower than the detection limit, the switch 10 of the ultraviolet lamp and the switch 11 of the blower of the photocatalytic air cleaning device 9 were turned off. Thereafter, the odor in Box 1 was smelled, but almost no odor was felt.

Next, the adsorbent air purifying device 7 and ten lit cigarettes are placed in a closed container of 1 m ³ similar to the box 1, and the adsorbent air purifying device 7 is operated to spontaneously burn tobacco. Smoke and odor were absorbed. This operation was repeated three times to adsorb smoke and odor of a total of 30 cigarettes on the adsorbent. After about 20 hours, the total amount of tobacco 3
Zero smoke and odor were adsorbed. Approximately 20 hours after this, an experiment for removing smoke and odor from a single cigarette was conducted in the same manner as in the case of the new adsorbent. With the use of the adsorbent, the area of the FID attenuated over time as 19 and the concentration of ammonia attenuated as 20. Then, when the change in each concentration became small at 21, when switching to the photocatalyst, the area of the FID attenuated over time as 22 and the concentration of ammonia attenuated as 23. When the respective concentrations became lower than the detection limit, the switch 10 of the ultraviolet lamp and the switch 11 of the blower of the photocatalytic air cleaning device 9 were turned off. Thereafter, the odor in Box 1 was smelled, but almost no odor was felt.

As described above, the present embodiment is a high-performance, deodorizing rate air-purifying method for quickly adsorbing a high-concentration odor gas using an adsorbent and decomposing the remaining gas by photocatalysis to make it odorless. Is the fastest way. In this case, the higher the gas concentration, the faster the adsorption speed and the adsorption capacity of the adsorbent, and the adsorbent adsorbs mist and high-boiling substances that shorten the life of the photocatalyst. In addition, the photocatalyst has a longer life when the gas concentration is lower, the decomposition rate (decay rate) is almost irrelevant to the concentration, and there is no fear of desorption seen in the adsorbent. Therefore, both the adsorbent and the photocatalyst can have a long life.

[0020] illustrating a second exemplary embodiment of the present invention with reference to Reference Example 2 4-7. In FIG. 4, reference numeral 31 denotes an air inlet, 32 denotes an air outlet, and 33 denotes a dust collecting filter. The dust collecting filter 33 has a diameter of 2 to 3 .mu.
It is a non-woven fabric of an ultra-fine and electretized polypropylene fiber having a length of m, and has been folded to increase the filter area and suppress pressure loss. 34-3
Reference numeral 9 denotes an adsorbent layer, reference numerals 40 to 45 denote photocatalyst layers, reference numerals 46 to 48 denote ultraviolet lamps, reference numerals 49 to 54 denote flow path switching means for switching air containing an odor gas between the adsorbent layer and the photocatalyst layer, and a reference numeral 55 denotes an air flow. Gas sensor for detecting gas concentration, 56 is a motor, 57
Is a fan, 58 is an air flow path, and 59 is a body of the air cleaning device.

[0021] as an adsorbent of the adsorbent layer 34 to 39 is San
Coconut shell activated carbon 4% impregnated similar aniline considered Example 1
170 g and 70 g of coconut shell activated carbon impregnated with 30% by weight of phosphoric acid were mixed and used. The particle size of the adsorbent is 6 mesh or more.
The mesh was 12 mesh. As in the case of Reference Example 1, the photocatalyst layers 40 to 45 were formed by coating an anatase type titanium oxide on a sheet made of ceramic fibers. Also,
The catalyst layer was corrugated to improve the contact with the air, and the total area was 1200 cm ² . On the other hand, the photocatalyst layers 40 to 4
As the ultraviolet lamps 46 to 48 facing 5, germicidal lamps with power consumption of 15 W are used. In addition, air is applied to the adsorbent layers 34 to 39.
Fan air volume as it passes through is about 2.5 m ³ / min, fan air volume as it passes through the photocatalyst layer 40-45 is approximately 1.2 m ³
/ Min. As the gas sensor 55, there are a semiconductor type, a catalytic combustion type, and a lipid bilayer type, and a semiconductor type includes a tin oxide / indium oxide / zinc oxide type. Here, a tin oxide type semiconductor gas sensor is used. .

Next, the operation of the air purifying apparatus of this embodiment will be described with reference to FIGS. First, the air cleaning apparatus of the present embodiment was placed in the box 1 of Figure 1 used in Reference Example 1. Then, one cigarette was burned and put in the box 1, and the same experiment as in Reference Example 1 was performed. At this time, the flow path switching means 49
In FIGS. 4 to 5, the flow paths on the photocatalyst layers 40 to 45 side are closed as shown in FIG. FIG. 6 shows a change in the output of the gas sensor 55 when this experiment is performed, and FIG. 7 shows a time change of the entire area of the peak of the FID detector.

The operation of this experiment was performed as follows. The initial value is measured when all the tobacco is burned. Immediately after the initial value measurement, turn on the power of the air purifier. At this time,
Since a large amount of gas is generated in the box 1, the output of the gas sensor 55 is large. At this time, the flow path switching means 49 to 54 are controlled so as to close the flow path on the photocatalyst layer 40 to 54 side.
Since the heater 56 is operated, dirty air is sucked in the direction A. As a result, tobacco smoke and gas are sucked from the air suction port 31, and smoke and mist are removed from the dust collection filter 33.
Removed by. Further, the gas is rapidly adsorbed by the adsorbent layers 34 to 39 and exits from the air outlet 32 through the air flow path 58. At this time, the output of the gas sensor 55 is 6 in FIG.
In the curve shown in FIG. 7, the total area of the FID peak is shown in FIG.
Rapidly decays in a curve such as 62.

Thus, when the adsorbing capacity of the adsorbent layers 34 to 39 reaches the limit, the attenuation of the curves 60 and 62 becomes gentle. A control circuit such as a microcomputer determines the magnitude of the decay speed, and if the speed is still sufficiently higher than a preset speed, suction is continued in the A direction. When it can be determined that the speed has decreased, first, the ultraviolet lamps 46 to 4 are used.
Then, the control direction of the flow path switching means 49 to 54 is set to the state of 49a to 54a. That is, the adsorbent layer 3
By closing the flow passages on the 4-39 side, air is supplied to the photocatalytic layer 40 in the B direction.
The suction is performed to the side of .about.45. At this time, the photocatalyst layer 40
45 are excited and activated by ultraviolet lamps 46-48. Therefore, the remaining gas that has touched the photocatalyst layers 40 to 45 is oxidized and decomposed, and flows out of the air outlet 32 through the air flow path 58. At this time, the output of the gas sensor 55 attenuates as shown by 61 in FIG.
The entire area of the curve shows a nearly linear attenuation as shown at 63 in FIG. Here, in the present reference example, the output of the gas sensor, which almost eliminates odor, is obtained in advance, and when the output becomes weak and close to this, the timer is operated, and after a certain period of time, the fan is stopped to allow air to enter. At the time when it disappears, the ultraviolet lamps 46 to 48 are finally stopped.

FIG. 7 shows a book 64-69.
The air purifying apparatus of the reference example was replaced with the box 1 of FIG.
, And at the same time, one tobacco is burned and placed in the box 1, and the change in the total area of the FID peak when the experiment is performed is shown. 64 and 65 are after approximately 1000 hours of operation (equivalent to half a year as 6 hours a day), 66 and 67 are after approximately 2000 hours of operation (equivalent to one year use), and 68 and 69 are approximately 40 hours.
The decay curve after 00 hours of operation (corresponding to two years of use) is shown. Reference numerals 70, 71, and 72 indicate the times when the adsorbent layer was switched to the photocatalyst layer.

[0026] According to the present embodiment, it is possible to not feel by using an adsorbent, a photocatalyst-gas sensors, the sooner odor by automatically. In addition, if you continue to use, the capacity of the adsorbent will decrease and the output of the ultraviolet lamp will gradually deteriorate, but since they can compensate for each other's defects, the purification speed will slow down, but almost no odor will be over the years. Can be used until no longer felt.

Embodiment 1 Next, a first embodiment of the present invention will be described with reference to FIG. The configuration of the air purifying apparatus of this embodiment is the same as that shown in FIG. When the odor gas is generated, the gas sensor 55
Starts odor detection. In addition, flow path switching means 49 to 54
Is controlled so as to close the flow path on the photocatalyst layers 40 to 45 side. In this state, the fan 57 and the motor 56 are operated to suck dirty air in the direction A. Next, in this embodiment, after a time proportional to the magnitude of the initial output of the gas sensor 55, that is, from the maximum output of the first gas sensor, the capacity of the adsorbent and the capacity of the photocatalyst are estimated by a microcomputer or the like, and the switching timer 80 Is activated. When the switching timer 80 finishes measuring the predetermined time, the ultraviolet lamps 46 to 48 are turned on, and at the same time, the flow path switching means 49 to 54 are controlled to switch to the photocatalyst layers 40 to 45. Further, when a predetermined time has elapsed, the operation of the fan 57 is stopped, and then the ultraviolet lamps 46 to
48 is turned off.

[0028]

According to the present invention, in accordance with the output of the initial gas sensor, to predict a time change of the gas concentration decreases, automatically and efficiently deodorized can air cleaning by switching the flow path by the switching timer An apparatus can be provided.

[Brief description of the drawings]

Sectional view of the first of the experimental apparatus is a reference example of the present invention; FIG

FIG. 2 is a diagram showing a flow showing the procedure of the experiment.

FIG. 3 is a diagram showing a change in gas concentration.

Longitudinal sectional view of the air cleaning apparatus is a second reference example of the present invention; FIG

FIG. 5 is a flowchart showing an operation procedure of the air cleaning device.

FIG. 6 is a diagram showing a change in the output of the gas sensor.

FIG. 7 is a diagram showing a change in a total area of a peak of the FID detector.

FIG. 8 is a diagram showing a flow of an operation procedure of the air purifying apparatus according to the first embodiment of the present invention.

[Explanation of symbols]

 7 Adsorbent air purifier 9 Photocatalyst air purifier 33 Dust collection filter 34-39 Adsorbent layer 40-45 Photocatalyst layer 46-48 Ultraviolet lamp 49-54 Channel switching means 55 Gas sensor

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61L 9/16 B01D 53/34-53/90

Claims (1)

(57) [Claims] 1. A gas sensor for detecting gas concentration in air, an adsorbent layer and a photocatalyst layer for passing air containing odor gas, and an air containing odor gas is detected by the gas sensor to detect the gas containing odor gas. An air purifying apparatus comprising: a flow path switching unit that switches to a photocatalytic layer for guiding; and a switching timer that switches the flow path switching unit after a time proportional to the magnitude of the initial output of the gas sensor.