JPH1147546A - Purification treatment method of exhaust gas and purification apparatus for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purification treatment method of an exhaust gas and apparatus for the same capable of efficiently removing a toxic constituent contained in an exhaust gas and performing circulating use of water used for removing. SOLUTION: A neutral ozone water having an ozone content of 3 ppm or higher is mixed into an exhaust gas generated from a combustion facility 10 so as to separate an organic substance and an inorganic substance from each other, and the inorganic substance is removed from the exhaust gas containing the inorganic substance and the inorganic substance is contained in water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying waste gas using ozone and a purifying apparatus therefor.

[0002]

2. Description of the Related Art Waste gas generated in combustion facilities such as boilers and incinerators contains harmful substances such as chloroform, lead and zinc. It has an adverse effect and causes photochemical smog. 2. Description of the Related Art Conventionally, there have been known methods and apparatuses for removing various substances contained in exhaust gas generated in combustion equipment. For example, Japanese Patent Application No. 60-251917
As shown in the figure, in order to remove NO in exhaust gas,
It has been conventionally known that ozone gas is added to exhaust gas.

[0003] By mixing ozone with the exhaust gas, SOx, NOx, and NO contained in the exhaust gas can be removed. However, no harmful substances other than SOx, NOx, and NO are removed and the exhaust gas is removed. Remains. As described above, a method and an apparatus for efficiently removing harmful substances and the like (hereinafter referred to as “harmful components”) contained in exhaust gas have not been known.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and has been made to efficiently remove harmful components contained in exhaust gas, and to make it possible to recycle water used for the removal. It is an object of the present invention to provide a purified exhaust gas purifying method and a purifying apparatus therefor.

[0005]

In order to achieve the above object, a method for purifying exhaust gas according to the present invention comprises mixing neutral ozone water having an ozone concentration of 3 ppm or more with exhaust gas generated from a combustion facility. Thereby, the exhaust gas is separated into an organic substance and an inorganic substance, the inorganic substance is removed from the exhaust gas containing the inorganic substance, and the inorganic substance is contained in water.

In order to achieve the above object, a purification apparatus according to the present invention comprises a reaction tunnel for introducing exhaust gas generated from a combustion facility and injecting ozone water into the inside, a reaction tunnel for the reaction tunnel and the atmosphere. An air passage that communicates with the air passage, a blower that is provided in the middle of the air passage and sends out the air in the reaction tunnel and the air passage to the atmosphere, an ozone mixer that mixes ozone with the water that has passed through the reaction tunnel, A filter for filtering water that has passed through the ozone mixer, and an ozone maker that adds ozone to the water that has passed through the filter to produce ozone water for injection into the reaction tunnel. It is assumed that.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1 is a system diagram showing an overall configuration of an example of an exhaust gas purification processing apparatus according to the present invention, and FIG. 2 is a system diagram showing another example of the same. When garbage, coal, petroleum, charcoal, and the like are burned in a combustion facility 10 such as a boiler or an incinerator, exhaust gas containing harmful components is generated. Exhaust gas generated in the combustion equipment 10 is introduced into a reaction tunnel 14 for reacting harmful components in the exhaust gas via an introduction passage 12. The exhaust gas generated in the combustion equipment 10 is, for example, 600 ° C. to 800 ° C.
° C, but the high-temperature exhaust gas passes through the long introduction passage 12.
Cooled while passing through. In the reaction tunnel 14, at a position where high-concentration ozone water described below is shower-injected, the temperature of the exhaust gas is required to be 60 ° C. or less. For this reason, in the illustrated example, a cooling device 16 is provided on the introduction passage 12 side of the reaction tunnel 14, and the cooling device 1 is provided.
6, the exhaust gas entering the reaction tunnel 14 is cooled. The cooling device 16 may be provided also in the introduction passage 12. The introduction passage 12 is sufficiently long and the reaction tunnel 1
If the temperature of the exhaust gas becomes 60 ° C. or lower when the temperature reaches 4, the cooling device 16 need not be provided in the reaction tunnel 14.

An ozone water supply passage 18 for supplying high-concentration ozone water is connected in the middle of the reaction tunnel 14. The ozone water supply passage 18 supplies 3 ppm or more high-concentration ozone water to the inside of the reaction tunnel 14. It is supposed to. The reaction tunnel 14 has a first vertical portion 20 at a position close to the introduction passage 12, and a main portion of the first vertical portion 20 is shown in FIG. As shown in FIG. 2, an ozone water supply passage 18 is introduced at a position slightly higher than the first vertical portion 20 to open its tip, and the reaction tunnel 14 is opened from this opening.
High-concentration ozone water is spouted into the inside of a shower. At the communication position with the ozone water supply passage 18, the temperature of the exhaust gas in the reaction tunnel 14 is set to 60 ° C. or less. The reason for setting the temperature of the exhaust gas to 60 ° C. or lower is that if the temperature is 60 ° C. or higher, ozone contained in the supplied high-concentration ozone water is vaporized, so that ozone is not vaporized from the high-concentration ozone water. is there. Further, the connection position of the reaction tunnel 14 with the ozone water supply passage 18 must not be a position (the highest position of the first vertical portion 20) that horizontally communicates with the exhaust gas of 60 ° C. or higher. 60 ° C
If high-concentration ozone water is injected at the position (the top of the first vertical portion 20) that is in horizontal communication with the exhaust gas, the ozone water may flow upstream of the first vertical portion 20 in some cases. Therefore, ozone contained in the high-concentration ozone water is vaporized, which is to avoid this.

In FIG. 1, in the reaction tunnel 14,
High-concentration ozone water is injected at the two locations. That is, the reaction tunnel 14 has, in addition to the first vertical portion 20 shown in FIG. 2, a second vertical portion 22 downstream thereof. The second longitudinal portion 22 is shown in FIG. The ozone water supply passage 18 is connected to the uppermost position of the second vertical portion 22 and its tip is opened. High-concentration ozone water is jetted from the opening into the reaction tunnel 14 in a shower shape. The reason why the exhaust gas is showered with the high-concentration ozone water twice is to lower the temperature of the exhaust gas and promote the separation (described later) of organic substances and inorganic substances contained in the exhaust gas. In FIG. 1, high-concentration ozone water is jetted into the reaction tunnel 14 from two places, but high-concentration ozone water may be jetted into three or more places. Alternatively, high-concentration ozone water may be injected into the reaction tunnel 14 at only one location. In that case,
A long vertical portion will be formed in the reaction tunnel 14.

In the reaction tunnel 14, high-concentration ozone water of 3 ppm or more is injected into the exhaust gas,
The substances contained in the exhaust gas are separated into organic substances and inorganic substances. That is, when the ozone concentration of the ozone water is 3 ppm or more, the substances contained in the exhaust gas are separated into organic substances and inorganic substances. Here, the separated organic matter is included in the air in the exhaust gas, and the separated inorganic matter is included in water as a solid matter. At this time, dust contained in the exhaust gas is also contained in the water together with the inorganic substances. In addition, water containing inorganic substances reacts with SOx contained in the exhaust gas to generate a pH value.
It becomes highly acidic water (sulfuric acid) of about 2.0 to pH 3.9.

The reaction tunnel 14 is provided for bringing high-concentration ozone water into contact with the exhaust gas therein to separate substances contained in the exhaust gas into organic substances and inorganic substances.
The time required for the separation reaction is about 2 minutes. For this reason, the length of the reaction tunnel 14 is set to a length that allows the reaction to proceed sufficiently, for example, about 20 meters, and the inner diameter is set to about 30 cm. In the present invention, the length and inner diameter of the reaction tunnel 14 are not limited to these. There is a long horizontal portion from the middle of the reaction tunnel 14 to the downstream side. A reaction accelerating device 24 is provided at the most downstream side of the reaction tunnel 14. Reaction promoting device 2
Reference numeral 4 denotes an apparatus for accumulating high-concentration ozone water in the reaction tunnel 14 for a long time and bringing it into contact with exhaust gas. As shown in FIG. 4, the reaction accelerating device 24 includes a weir 26 for storing high-concentration ozone water in a horizontal portion of the reaction tunnel 14, and an upper side in the reaction tunnel 14 downstream from the position of the weir 26. And a baffle 28 for temporarily blocking the passage of exhaust gas. By retaining water in the reaction tunnel 14 by the weir 26 and preventing the exhaust gas from flowing smoothly by the baffle plate 28, the reaction between the high-concentration ozone water and the exhaust gas is further promoted.

The separation tank 3 is located downstream of the reaction tunnel 14.
Connected to 0. In the reaction tunnel 14, the exhaust gas becomes air containing organic matter, and the high-concentration ozone water becomes sulfuric acid containing inorganic matter and dust. In some cases, air containing organic matter contains a small amount of ozone gas. The separation tank 30 is for separating air containing organic matter and exhaust gas, and sulfuric acid containing inorganic matter and dust. Although not shown in FIG. 1, high-concentration ozone water may be shower-injected again from the upper part inside the separation tank 30. An exhaust passage 32 communicating with the atmosphere is attached to the upper part of the separation tank 30.
A blower 34 is provided on the way. In the middle of the exhaust passage 32, the exhaust passage 32 is provided upstream of the blower 34.
An ozone removing means 36 for removing ozone contained in air passing through is provided. The ozone removing means 36
Any device may be used as long as the air passing therethrough is heated to 60 ° C. or higher, and the ozone is heated to 60 ° C. or higher to decompose the ozone into oxygen. By operating the blower 34, the air in the exhaust passage 32, in the separation tank 30, and in the reaction tunnel 14 is discharged from the exhaust passage 32 to the atmosphere. The air in the separation tank 30 contains organic matter and ozone that has not been decomposed, but ozone passing through the exhaust passage 32 is removed by the ozone removing means 36, and only air containing organic matter is discharged from the exhaust passage 32 to the atmosphere. Will be released. The air containing the organic matter from which ozone has been removed is clean air that does not cause pollution, whereby the exhaust gas generated by the combustion equipment 10 can be purified into clean air and released to the atmosphere.

The water introduced into the separation tank 30 is strongly acidic water (sulfuric acid) containing inorganic substances and having a pH of about 2.0 to 3.9.
Will be introduced. The filtering device 40 comprises a first filtering means 42 and a second filtering means 44. The first filtering means 42 is, for example, a filter for filtering large solids, and the second filtering means 44 is, for example, a sand for filtering small solids. And Both the first filtration means 42 and the second filtration means 44 may be any as long as they can remove inorganic solids and dust. When sand is used as the filter medium, the filter medium can be washed by spraying water in the reverse direction, and cleaning management is easy. In addition, although the filtration device 40 was comprised from the two types of filters of the 1st filtration means 42 and the 2nd filtration means 44, you may use one type of filter. Also,
This filtering device 40 may be omitted.

The water passed through the filtration device 40 is supplied to a pump 46.
To the water storage tank 48. The water introduced into the water storage tank 48 has a pH of 2.0 to p from which inorganic solids have been removed.
It is strongly acidic water of about H3.9. However, this strongly acidic water contains inorganic substances dissolved in the water. Next, the strongly acidic water stored in the water storage tank 48 is introduced into the ozone utilization purifying device 50. The ozone utilization purification device 50 is for removing inorganic substances dissolved in water. Here, the structure of the ozone utilization purifying apparatus 50 is shown in FIG. The ozone utilization purifying device 50 includes a first ozone mixer 52, a first filter 54, a second ozone mixer 56, and a second filter 5
8 to pass strongly acidic water from the water storage tank 48 in that order. The ozone utilization purifying device 50 further includes an ozone generator 60 for supplying ozone to the first ozone mixer 52 and an ozone generator 62 for supplying ozone to the second ozone mixer 56. In the first ozone mixer 52, strongly acidic water and ozone from the ozone generator 60 are mixed to solidify the easily oxidizable organic and inorganic substances dissolved in the strongly acidic water. Also, it kills bacteria such as whistles present in water. The first filter 54 is for removing the solid matter generated by the first ozone mixer 52, and stores, for example, sand therein. In the second ozone mixer 56, the strongly acidic water introduced from the first filter 54 and ozone from the ozone generator 62 are mixed,
Organic and inorganic substances that have not yet been solidified by being dissolved in strongly acidic water are solidified. Also in the second ozone mixer 56, bacteria such as viruses existing in water are sterilized.
The second filter 58 is for adsorbing and removing the organic matter and the inorganic matter solidified by the second ozone mixer 56, and stores therein, for example, activated carbon. First filter 5
The fourth filter 58 removes inorganic substances (also organic substances) contained in the water. In the ozone utilization purifying apparatus 50, two types of ozone mixers 52 and 56 are used, respectively.
And ozone generators 60 and 62, but only one type may be used. However, by dividing into plural types, each device can be miniaturized, different types of filter media can be used, and organic and inorganic substances contained in water can be efficiently removed. The filtration device 40 may be provided after the ozone utilization purification device 50, not before the ozone utilization purification device 50.

The water from which organic and inorganic substances have been removed by the ozone purifying apparatus 50 is introduced into a water storage tank 64. The water introduced into the water storage tank 64 is still strongly acidic water having a pH of 2.0 to 3.9. The water from the water storage tank 64 is introduced into the ozone water producing device 66. Ozone produced by the ozone generator 68 is also introduced into the ozone water generator 66, and the ozone is mixed with strongly acidic water from which organic and inorganic substances have been removed. In this ozone water producing device 66, high-concentration ozone water of pH 6.5 is produced from water of pH 2.0 to pH 3.9. By removing organic substances and inorganic substances, neutral water having a pH of about 6.5 can be produced from water having a pH of 2.0 to 3.9 in the ozone water producing device 66. At present, high concentration ozone water of 3-9ppm can be produced, but 9ppm
It is possible to separate organic matter and inorganic matter even with high-concentration ozone water. In other words, pH 2.
From highly acidic water of 0 to 3.9, it is converted to neutral, high concentration ozone water of 3 ppm or more. The neutral high concentration ozone water of 3 to 9 ppm is supplied to the reaction tunnel 16 through the ozone water introduction passage 18.
Spray as a shower.

Since the present invention can be applied to the exhaust gas purifying apparatus configured as illustrated in FIG. 6, the method described with reference to FIGS. The gas purification processing device will be described.

In FIG. 6, reference numeral 71 denotes a combustion facility; 72, a flue serving as an exhaust gas introduction passage; 73, an inlet of a reaction tunnel 74 connected to the flue;
High concentration ozone water shower nozzle provided in the middle of
Is a reaction water tank, 76 is a reaction flue, 77 is a shower nozzle of ozone water, and 78 is an outlet of the reaction flue.

The exhaust gas arriving at the reaction thinner 74 through the flue 72 has a temperature of 600 ° C.
Because of the high temperature of 800 ° C., it is necessary to lower the temperature to about 60 ° C. or less before reaching the shower nozzle 89. Therefore, although not shown, a cooling unit (not shown) is provided with smoke before the shower nozzle 89. Road 72-Reaction tunnel 74
May be provided between them.

By subjecting the exhaust gas to high concentration ozone of 3 ppm or more in the reaction tunnel 74, substances contained in the exhaust gas are separated into organic substances and inorganic substances. The separated organic matter is included in air, and the separated inorganic matter is included in water as a solid. The water contains dust contained in the exhaust gas together with the inorganic solids. The water containing the inorganic substance becomes strong acid water (sulfuric acid) having a pH of about 2.0 to 3.9 by reacting with SOx in the exhaust gas.

Air containing organic matter and strongly acidic water containing inorganic substances flow down the reaction tunnel 74 and are stored in a reaction water tank 75, where they are separated into gas and liquid. Since the separated air is introduced into the outlet side through the reaction flue 76, high-concentration ozone of 3 ppm or more from the ozone shower nozzle 77 is also added to the air containing the organic matter in the reaction flue 76. The injection separates substances that are not separated in the above-described reaction tunnel 74 but are still contained in the exhaust gas into inorganic substances and organic substances. Therefore, the reaction water tank 75 serves as the reaction promoting device 24 and the separation tank 30 described above.

Above the reaction tank 75, an exhaust flue 80 communicating with the atmosphere is connected to an outlet 78 of the reaction flue 76,
In the middle of the exhaust flue, an ozone removing means 81 for removing ozone contained in the air passing through the flue 80 and a blower 82 are inserted, and the purified smoke (air) is led out to an outlet 83 thereof. It has been like that.

On the other hand, the strongly acidic water separated in the reaction water tank 75 passes through a pipe 84 including a pump to a pH of about 2.0 to 3.9.
The degree is sent to a washing / purifying device 85 of strong acidic water.
This device 85 has a structure similar to that of the above-described filtering device 40, and has the same functions and functions as those of the filtering device 40.

The water purified by the cleaning / purifying device 85 is accumulated in a temporary storage tank 86 and sent to the next neutralizing device 87, where it is formed into neutral water having a pH of about 6.5. Is done. The neutralized water is passed through an ozone generator 87 to form high-concentration ozone water having a pH of about 6.5, and the ozone water passes through ozone water supply passages 79 and 90 and a high-concentration ozone water shower 77. , 89.

[0024]

As described above, according to the exhaust gas purifying method and the purifying apparatus according to the present invention, a neutral and 3 pp
By mixing high-concentration ozone water of m or more with exhaust gas, organic substances and inorganic substances contained in the exhaust gas can be separated. Accordingly, the exhaust gas can be purified by discharging the exhaust gas to the atmosphere together with the air, and by adding the inorganic substance to the water and removing the inorganic substance from the water. In the present invention, the water used for purifying the exhaust gas can be circulated and used inside the device, and the water used for purifying the exhaust gas does not need to be separately treated outside the device. It is also highly likely. In this sense, the device of the present invention is an environment support type device.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an entire configuration of an example of an exhaust gas purification treatment apparatus of the present invention.

FIG. 2 is an enlarged sectional view of a main part of a vertical portion of a reaction tunnel in the apparatus of the present invention.

FIG. 3 is an enlarged sectional view of a main part of another longitudinal portion of the reaction tunnel in the apparatus of the present invention.

FIG. 4 is a cross-sectional view of an example of a reaction promoting device in the device of the present invention.

FIG. 5 is a block diagram showing a configuration of an ozone utilization purifying apparatus in the apparatus of the present invention.

FIG. 6 is a system diagram showing the overall configuration of another example of the exhaust gas purification treatment device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Combustion equipment 14 Reaction tunnel 16 Cooling device 18 Ozone water supply device 20 First vertical portion 22 Second vertical portion 24 Reaction promoting device 30 Separation tank 32 Exhaust passage 34 Blower 36 Ozone removing means 40 Filtration device 50 Ozone utilization purification device 52 first ozone mixer 54 first filter 56 second ozone mixer 58 second filter 60 ozone generator 62 ozone generator 66 ozone maker 68 ozone generator

Claims (14)

[Claims] An exhaust gas generated from a combustion facility is mixed with ozone water having a neutral ozone concentration of 3 ppm or more to separate the exhaust gas into an organic substance and an inorganic substance. A method for purifying exhaust gas, comprising removing the inorganic substance and including the inorganic substance in water. 2. The exhaust gas purification method according to claim 1, wherein the temperature of the exhaust gas for injecting the high-concentration ozone water is set to 60 ° C. or lower. 3. The exhaust gas purification method according to claim 1, wherein the high-concentration ozone water is injected into the exhaust gas at two or more locations in the exhaust gas passage. 4. The exhaust gas purification method according to claim 1, wherein the exhaust gas from which the inorganic substances have been removed is released into the atmosphere via an ozone removing device. 5. The exhaust gas purifying method according to claim 1, wherein the inorganic substance contained in water is mixed with ozone to solidify the inorganic substance, and the inorganic solid substance is removed by a filter. . 6. The exhaust gas purification process according to claim 5, wherein ozone is mixed with the water from which inorganic solids have been removed by a filter to produce neutral ozone water, and the ozone water is mixed with the exhaust gas. Method. 7. A reaction tunnel for introducing exhaust gas generated from a combustion facility and injecting ozone water into the inside thereof, an atmosphere passage connecting the reaction tunnel to the atmosphere, and a midway in the atmosphere passage. A blower that sends air in the reaction tunnel and the atmosphere passage to the atmosphere, an ozone mixer that mixes ozone with the water that has passed through the reaction tunnel, and a filter that filters water that has passed through the ozone mixer, An exhaust gas purifying apparatus, comprising: an ozone producing device for producing ozone water for adding ozone to water passed through the filter and injecting the ozone into the inside of the reaction tunnel. 8. The exhaust gas purifying apparatus according to claim 7, wherein a vertical portion is formed in the middle of the reaction tunnel, and ozone water is injected from above the vertical portion. 9. The exhaust gas purifying apparatus according to claim 8, wherein a plurality of vertical portions for injecting ozone water from above are formed in the middle of the reaction tunnel. 10. The exhaust gas purifying apparatus according to claim 7, further comprising a reaction weir provided downstream of the reaction tunnel with a weir for damming water and a baffle plate slightly downstream of the weir for preventing gas from going straight. . 11. The exhaust gas purifying apparatus according to claim 10, wherein the reaction tunnel on the upstream side of the weir is in a long horizontal state. 12. The exhaust gas purifying apparatus according to claim 7, further comprising an ozone removing device for removing ozone in the middle of the atmosphere passage. 13. A filter device for removing solids and dust before water that has passed through the reaction tunnel reaches the ozone mixer, and the water is allowed to pass therethrough.
An exhaust gas purifying apparatus according to any one of the above. 14. A plurality of sets of an ozone mixer and a filter are arranged in series in that order, and the filter medium of one of the filters is sand.
The exhaust gas purifying apparatus according to any one of claims 7 to 13, wherein the filter material of the other filter is activated carbon.