JPS5817647B2 - air purification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In recent years, air pollution caused by carbon oxides and nitrogen oxides has become a problem.

Carbon monoxide (hereinafter referred to as CO) and nitrogen oxides (hereinafter referred to as NO)
The sources of chemical substances (referred to as x) are mobile sources such as automobiles and stationary sources such as large boilers, and their removal is strongly desired as they pose a pollution problem and threaten the health of local residents.

Due to this social background, the total emissions of CO and NOx from mobile sources such as automobiles have been reduced due to the Exhaust Gas Control Law, but the
Underground parking lots still have high concentrations of CO and NOx, which is harmful to the health of local residents.

CO easily binds to hemoglobin in the blood, and when inhaled in large quantities, it causes poisoning symptoms such as headaches, dizziness, and paralysis of the limbs, eventually leading to death.

NOx is also a toxic gas that irritates the nose and eyes, and if inhaled in large quantities, it causes pulmonary edema and ultimately leads to death.

Therefore, the government also set CO: 10pI) as an environmental standard value.
II, No. 2: We are promoting environmental purification by setting 0.02pI)m, but there are many days when the environmental standard value is exceeded, and air purification is strongly desired.

Currently, there are electric dust collectors that remove dust and fine particles, and air purifiers that use nonwoven fabrics such as acetate, but they cannot remove harmful gases such as CO and NOx.

The inventors have already invented a kneaded molded product containing alkali, cement material, and powdered activated carbon as main components as a filter for removing NO2 gas at room temperature.

In addition, as a catalyst for oxidizing CO at room temperature, platinum, rhodium, and
One or more selected from ruthenium and palladium at the same time,
Alternatively, it has been found that a catalyst supported solely on palladium is effective.

When the above harmful gas remover and activated carbon are combined with a blower, it is possible to purify indoor air, but if the CO detection element detects CO present in the room and inputs the information to the air purification equipment, it will automatically be activated when the air becomes contaminated. This method is expected to become widely popular because it has the advantage of saving energy because it starts operating at a certain time and automatically stops when it is clean.

At that time, the presence of CO in the air is required, but when fuel is burned, such as in internal combustion engines such as cars, combustion appliances such as kerosene stoves, cooker burners, and cigarette smoke, CO and NO are always released.
x occurs.

Therefore, CO is the best measure of indoor air pollution.

At this time, if the detection concentration of CO is set to a low value, the air purification equipment will automatically start operating due to the presence of a trace amount of CO, and NOx and other harmful gases can also be removed by the attached harmful gas removal filter.

Since the CO level attenuated by the CO removal filter becomes less than the amount detected by the CO detection element, the air purification equipment automatically stops operating.

Traditionally, air purification aims to remove dust and particulates.
Many electrostatic precipitators and non-woven fabrics have been devised, but none of these methods can remove harmful gases such as CO and NOx.

Activated carbon is a filter that removes NOx at room temperature, but activated carbon has a short lifespan.

It also reduces N02 to NO at high temperatures. Furthermore, NO2 is desorbed depending on the operating conditions.

Furthermore, it had drawbacks such as not removing NO, making it unsuitable as a NOx removal filter.

Catalysts that oxidize and remove CO to CO2 include a copper-manganese hobcalide catalyst and a carrier such as alumina with platinum and
There are catalysts that support palladium, a noble metal.

Hobcalide catalysts oxidize CO even at room temperature, but their activity decreases in the presence of water vapor, and noble metal supported catalysts sensitize CO at high temperatures of 100°C or higher.

Therefore, in order to oxidize and remove CO using conventional catalysts, large-scale equipment was required to heat air, react with the catalyst at high temperature, and cool the heated air to room temperature.

Therefore, there has been a strong desire to develop a catalyst that oxidizes CO at room temperature.

The catalyst used in the present invention oxidizes CO even at room temperature, and when the catalyst layer is brought into contact with air containing CO at room temperature, CO is oxidized.
is removed.

Further, since a kneaded molded product of alkali, cement material, and powdered activated carbon removes NO2 at room temperature, NO2 is removed when it is brought into contact with air containing NO2.

Activated carbon filters are effective in removing foul-smelling gases from the air.

When a CO oxidation catalyst layer, NO2 removal agent (kneaded molded product), and activated carbon filter are installed together and brought into contact with indoor air, Co-N0□, foul-smelling gas, etc. in the air are removed, but conventional air purification equipment has to be operated manually. Regardless of the level of air pollution, driving has been determined by the will of the people living there.

As a result, there are many unreasonable situations in which air purification equipment remains stopped even though the room is contaminated, and air purifiers continue to operate even though the room is not contaminated. The purifier's original intent was to purify the air.

Since air purification is carried out when the air is contaminated, the present invention detects the indoor contamination status using a CO detection element and operates an air purification device to purify the blank air.

FIG. 1 is an explanatory diagram of a floor-standing air cleaner having an electrostatic precipitator.

Indoor air flowing in through the air suction port 1 is subjected to an electrostatic precipitator 2 to remove dust and particulates.

Activated carbon filter 3 removes bad odor gas, NO2 remover 4
Indoor air from which NO2 has been removed by a kneaded molded product of alkali, cement material, and powdered activated carbon, and CO has been removed by a CO oxidation catalyst 5, passes through a blower 6 and is discharged into the room from a blow-out lower.

The operation of the air purifier is based on the CO detected by the CO detection element 8.
Bacteriostatic control due to O yield.

CO oxidation catalyst 5 is activated carbon filter 3 and NO□ removal cutter 4
installed in the wake of the

This is because there is a concern that the catalyst 5 may be poisoned by NOx or foul-smelling gas in the air, and an activated carbon filter 3 and a NO2 remover 4 are installed upstream to prevent poisoning.

NO2 remover 4 is a kneaded molded product of alkali, cement material, and powdered activated carbon.The alkali is potassium carbonate and calcium hydroxide, and the cement material is calcined gypsum (CaSO4.
1/2H20) removed NO2 well.

The CO oxidation catalyst 5 is a catalyst in which one or more selected from platinum, rhodium, and ruthenium and palladium are supported at the same time or palladium alone on a carrier made by kneading and molding alkali, cement material, and powdered activated carbon. Potassium carbonate, those using lime aluminate as a cement material, and those that simultaneously supported platinum and palladium as noble metals oxidized CO well.

Therefore, as the CO oxidation catalyst 5, platinum and palladium are simultaneously supported on a kneaded molded product of potassium carbonate, lime aluminate, and powdered activated carbon.

The CO detection element 8 is made by sintering porous alumina (At203) onto a coiled platinum wire to form a bead shape, coating the bead with a platinum metal catalyst (Pt, Pd, Pa-Pt), and firing it. It was used.

The CO detection element 8 detects the CO@ degree, and when a set concentration or higher is detected, the air purifier automatically operates.

If the concentration is below the set level, it will automatically stop and operation will be controlled based on the detected concentration.

The present invention can also be applied to other air purifying devices that include a blower.

The filter configuration is a CO oxidation catalyst installed in the downstream of the air flow path, and the upstream is without a filter, activated carbon filter, NO□ remover, activated carbon filter and NO2
Although it is possible to use the remover at the same time, it is preferable to use activated carbon and the NO2 remover at the same time.

Figure 2 shows a kerosene stove, which is an open combustion appliance, in order to purify the air by installing a blower, a harmful gas filter, and a carbon monoxide detection element above the combustion section for the purpose of removing CO and NOx generated by the stove. An air cleaner 17 is shown.

The heat generated from the combustion part 10 of the kerosene stove 9 is transferred to the reflector 1
1, the air containing CO and NOx rises through the top plate 12.

The blower 14, which detects CO above a specified concentration using the carbon monoxide detection element 13, rotates and blows out hot air from the outlet 15, and a harmful gas removal filter 16 installed at the outlet 15 removes NOx and CO.

The optimal configuration of the harmful gas removal filter 16 is to have an NO2 removing agent in the front stream and a catalyst layer in the back stream.

The carbon monoxide detection element 13 activates the air cleaner 17 when the detection concentration is higher than the specified concentration, and stops the air cleaner 17 when the concentration is lower than the specified concentration.

The installation position of the air cleaner 17 was adjusted so that the temperature of the catalyst layer was 70 to 80°C.

Figure 3 shows an air purifier that purifies the air by installing a blower, a harmful gas filter, and a carbon monoxide detection element above the combustion part of a cookware burner as an open combustion appliance.

CO generated from the combustion part 19 of the cookware burner 18
and NOx flow into the air purifier 20, and when the carbon monoxide detection element 21 installed inside detects CO at a detection standard concentration or higher, the blower 22 rotates and removes the harmful gas removal filter 2.
3 to purify CO\)NOx.

The optimal configuration of the harmful gas removal filter 23 is to install an NO2 removing agent in the front stream and a catalyst layer in the back stream.

The carbon monoxide detection element 21 controls the operation of the air cleaner 20 based on the detected amount of carbon monoxide.

As an aggregate for removing NO2 present in the air, there is a kneaded molded product of alkali, cement material, and powdered activated carbon.

NaOH and KOH are used as alkalis. Ca(OH)22
Mg(OH)2. 2CO3, Na2CO3゜Na2S
2O3, Na2SO3 are suitable, especially 2CO3,
The one using Ca(OH)2 removed NO2 with high performance and was optimal.

Suitable cement materials include bentonite, diatomite, alumina cement, alumina sol, silica sol, clay, calcined gypsum, Portland cement, kaolin, water glass, etc., but those using calcined gypsum (CaSO4.1/2H20) are particularly suitable. The performance was optimized by removing NO2.

Powdered activated carbon plays the role of increasing the surface area of the kneaded and molded product and promoting the reaction between alkali and NO2.

The kneaded molded product and NO3 react as shown below to release N in the air.
It is believed that O2 is removed.

2NO2+ to 2CO3→KNO3+KNO□+CO24
N02+2Ca(OH)2→Ca(NO3)20Ca(
NO2)2+2H20 Note that it does not react with NO.

The composition of the kneaded and molded product was potassium carbonate/calcium hydroxide/calcined gypsum (CaSO4-1/2 H2O)/powdered activated carbon = 3/3/2/2 (weight ratio), which was kneaded and molded with water and then dried. used.

As a catalyst, one or more selected from the group of platinum, rhodium, and ruthenium and palladium or palladium alone was supported on a kneaded molded product of alkali, powdered activated carbon, and cement material.

The catalyst carrier was optimized so that the supported substance was supported uniformly over a wide range with a fine particle size, and the specific surface area of the carrier was large and the strength was high.

When supporting an alkaline earth metal, the pH of the impregnating solution in which the noble metal chloride is dissolved is changed to alkaline to help the noble metal be adsorbed onto the carrier in a fine and uniformly dispersed state.

Powdered activated carbon contributes to the pore physical properties of the carrier, such as increasing the specific surface area of the carrier.

The cement material increases the strength of the carrier and contributes to improving its heat resistance and wear resistance.

Examples of the alkali include potassium carbonate, potassium hydroxide, calcium hydroxide, and sodium carbonate, but potassium carbonate was the most suitable in terms of ease of use and performance.

Examples of cement materials include boltland cement, calcined gypsum, bentonite, and alumina cement whose main component is lime aluminate, but alumina cement was the most suitable in terms of performance.

The reason for this is the promoter effect of ferric oxide and calcium oxide contained in alumina cement.

In addition, noble metals such as platinum, rhodium, ruthenium, and palladium were used as supporting materials, with alumina serving as a binder and serving as a stable carrier.

Palladium, which is relatively inexpensive, becomes a highly active catalyst when used alone or in combination with other noble metals, and in particular, the combination of platinum and palladium exhibited a synergistic effect and achieved remarkable oxidation activity.

Next, a method for adjusting the catalyst will be explained.

Potassium carbonate is used as the alkali, and alumina cement is used as the cement material. Potassium carbonate has a particle size of 100 mesh, powdered activated carbon has a particle size of 300 mesh, and alumina cement has a composition of at least 45% alumina and ferric oxide. 10% or less was used.

The carrier was prepared by adding 0.5 part of sodium carboxymethyl cellulose (CMC) as a binder to 10 parts of potassium carbonate, 30 parts of powdered activated carbon, and 60 parts of lime aluminate in weight ratio, and kneading the mixture with water.

After thoroughly drying the mixed wire material, it was classified into 8 to 20 meshes and used as a carrier.

After the carrier was sufficiently dried, it was immersed in a solution containing palladium and platinum to effect adsorption.

The amounts of palladium and platinum were adjusted so that 0.3 wt% of each was adsorbed on the carrier.

The adsorbed carrier was reduced with sodium borohydride, thoroughly dried, and heat-treated at 300° C. for 1 hour to obtain a catalyst.

Figures 4 and 5 show the CO and NO2 concentrations measured in homes near busy intersections in the city center, and when an air purifier to which the present invention is applied (CO concentration set at 1 pyn) is operated. The measurement results for H without a purifier are shown.

The home in which the measurements were taken was a 6-tatami room (interior volume: 29.6 m''), the ventilation rate was 1.2 times/hr, and the room was not opened or closed during the measurements.

The air purifier has a flow rate of 4.0771″/m17L, and the filter consists of granular activated carbon, NO□ remover, and C from the front stream.
It consisted of an O oxidation catalyst layer, each layer had a layer height of 5 mm, and the filter area was 40 x 40 CrIl.

CO was analyzed using a non-dispersive infrared analyzer, and NO2 was analyzed using a chemiluminescent analyzer.

The N02 remover is a kneaded product of potassium carbonate, calcium hydroxide, calcined gypsum (CaSO, .1/2 N20), and powdered activated carbon.

The CO oxidation catalyst layer is a catalyst in which platinum and palladium are simultaneously supported on a carrier obtained by kneading and molding potassium carbonate, lime aluminate, and powdered activated carbon.

On the other hand, since hydrocarbons discharged from automobiles were present in the air, granular activated carbon was used to adsorb and remove the hydrocarbons.

Note that the granular activated carbon had no CO removal effect and only a slight NO2 removal effect; CO was removed by the CO oxidation catalyst layer, and most of the NO2 was removed by the NO3 removal agent.

As mentioned above, the reason for removing CO and NO2 at the same time is that when something burns, NO2 is also generated along with CO, so it was decided to remove both at the same time.At that time, CO was detected by a carbon monoxide detection element. The reason for operating a blower is that, as is well known, CO has a more harmful effect on the human body than NO2.

Measurements were conducted from 8 a.m. to 5 p.m.

In case (2) without an air purifier, the indoor C0-NO2 concentration was measured continuously in advance and confirmed that there was no change in the concentration throughout the day.

The air purifying device of the present invention not only significantly reduces indoor CO and NO2 concentrations, but also consumes less electricity.Furthermore, since the operation of the air purifier is controlled based on the CO concentration, the environment is purified according to the set concentration. Not only is it possible to do this, but it also starts operation when CO exists in the air above the set concentration, and automatically stops when the concentration drops below the set level, ensuring a clean and uncontaminated environment at all times. Depending on the gas composition, activated carbon or NO2 remover can be installed only in the catalyst layer or in the upstream of the catalyst layer, which reduces the possibility of being poisoned by other gases and provides an excellent air purifying function. .

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of an air purifier according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of an air purifier installed above a kerosene stove, and Fig. 3 is an explanatory diagram of an air purifier installed above a burner for cooking utensils. The explanatory drawings of the purifier, FIGS. 4 and 5, are characteristic diagrams showing changes in the indoor C0-NO2 concentration when the same air purifying device is used, respectively. 4...NO2 remover, 5...CO oxidation catalyst, 6...Blower, 8...CO detection element, 13...1 Carbon oxide detection element, 14...
...Blower, 16...Harmful gas removal filter, 17...Air purifier, 2o...
Air purifier, 21... Carbon monoxide detection element, 2
2... Blower, 23... Bent harmful gas removal filter 0

Claims (1)

[Claims] 1. A blower is used to send air to a harmful gas removal filter, and this harmful gas removal filter consists of: (1) potassium carbonate, calcium hydroxide, and calcined gypsum (Ca
Kneaded and molded product of powdered activated carbon (SO4 1/2 H2O) and powdered activated carbon (11) Consisting of the above (o, oa) of a catalyst in which platinum and palladium are simultaneously supported on a support of a kneaded and molded product of potassium carbonate, lime aluminate, and powdered activated carbon. An air purifying device that operates and stops the blower based on the signal from the carbon monoxide detection element. 2. The air purifying device according to claim 1, wherein the catalyst (11) is installed downstream of the air flow path rather than the kneaded and molded product (2) (I).