JP2001009239A - Waste gas treating device and waste gas purifying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To previously remove dioxin precursors and to effectively prevent the generation of dioxins by applying a heat resistant filter consisting of an aqueous film-formable inorg. compd. soln. to a waste gas treating stage of an incinerator. SOLUTION: This device is provided with a second waste gas treating device 30 arranged succeeding by to a first waste gas treating device 3, and the first waste gas treating device 3 Is constituted so that aqueous filme-formable inorg. compd. soln. consisting of a silanol salt and siloxane consisting essentially of Si, having film-formable property and working as the heat resistant filter may be jetted from a jetting part 9 into the waste gas. The second waste gas treating device 30 is provided with a shower feed unit 31 for feeding the soln. into a waste gas flow passage in a from like shower and a liq. film forming device for forming the liq. film formed by the soln. so as to Intercept the waste gas flow passage and for allowing the waste gas to pass by breaking the liq. film and the waste gas is purified by allowing the aqueous film-formable inorg. compd. soln. to contact stepwise with the waste gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for treating exhaust gas generated in an incinerator and, more particularly, to an apparatus and a method for purifying exhaust gas that effectively prevent the generation of dioxin in an exhaust gas treatment process. is there.

[0002]

2. Description of the Related Art Dioxin has a very high toxicity, and is said to be "the strongest and worst poison produced by mankind". Dioxin is an abbreviation for polychlorodibenzoparadioxin, which has been detected in many garbage incineration plants in the past. According to a study by Ehime University, dioxin, which is thought to be generated during the incineration of household waste,
It has been found that it has diffused and descended into the atmosphere.

It is said that in an incinerator, dioxin is generated when the exhaust gas temperature is 650 ° C. or lower and 200 ° C. or higher, and the exhaust gas temperature is 650 ° C. at the start of incineration, at the end of incineration, and in the exhaust gas treatment process after incineration. Dioxin is produced when: Particularly, in the exhaust gas treatment step, the exhaust gas is forcibly cooled before reaching the bag filter, so that there is a high possibility that dioxin is generated during the cooling.
Therefore, in the exhaust gas treatment step, it is desirable to remove the dioxin precursor (such as hydrogen chloride) before the temperature of the exhaust gas becomes 650 ° C. or lower.

[0004]

However, the conventional 650
Since there is no filter that can withstand a high temperature of more than ℃, it is usual to cool the high temperature exhaust gas to normal temperature and apply it to a bag filter. Therefore, the generation of dioxin could not be effectively prevented. In addition, 650 ° C
Conventionally, a method of adsorbing and removing dioxin precursors using activated carbon or slaked lime that can withstand the above temperatures has been tried. It was not a target.

The present inventors have previously developed an intumescent aqueous film-forming inorganic compound which can sufficiently withstand high temperatures of 650 ° C. or higher (Japanese Patent Publication No. 7-1480).
No. 1). And this aqueous film-forming inorganic compound is 65
It has been found that it functions as a heat-resistant filter for removing dioxin precursor at a high temperature of 0 ° C. or higher, and the present invention has been completed.

That is, an object of the present invention is to apply a heat-resistant filter comprising a solution of an aqueous film-forming inorganic compound to an exhaust gas treatment step of an incinerator to remove a dioxin precursor in advance and effectively prevent the generation of dioxin. An object of the present invention is to provide an exhaust gas treatment device and an exhaust gas treatment method that can be used.

[0007]

To achieve the above object, an exhaust gas treatment apparatus according to the first aspect of the present invention is provided with a first exhaust gas treatment apparatus and a second exhaust gas treatment apparatus. A second exhaust gas treatment device, wherein the first exhaust gas treatment device contains silicon (Si) as a main component,
It comprises a silanol salt and a siloxane, has a film forming property, and is configured to inject a solution of an aqueous film forming inorganic compound that functions as a heat resistant filter into an exhaust gas from an injection unit. A shower supply device for supplying a solution of the aqueous film-forming inorganic compound into the flow path of the exhaust gas in a shower form, and a liquid film formed by the solution of the aqueous film-forming inorganic compound blocking the flow path of the exhaust gas. A liquid film forming device formed so that the exhaust gas breaks through the liquid film and passes therethrough, wherein the aqueous film-forming inorganic compound comprises the exhaust gas, the first exhaust gas treatment device, and the second exhaust gas treatment device.
The exhaust gas is purified by contacting the exhaust gas in a stepwise manner with an exhaust gas treatment device.

According to the present invention, a solution of the aqueous film-forming inorganic compound is sprayed from the spraying section into the first exhaust gas treatment apparatus, so that the solution is gelled at the moment when the solution comes into contact with the high-temperature exhaust gas. Boiled, filled in the exhaust gas flow path, the dioxin precursor contained in the exhaust gas, and further the odorous component,
Black smoke and heavy metals are captured and included as heat resistant filters. When dioxin is partially generated, dioxin is captured and included. Also, by supplying the solution of the aqueous film-forming inorganic compound into the first exhaust gas treatment device,
An exhaust gas cooling effect is also obtained. In the process of contacting with high-temperature exhaust gas, bubbling, and capturing the dioxin precursor and the like, the solution is evaporated and dried, and the inclusion including the dioxin precursor and the like becomes a powder (solid portion). Most of the water falls off the bottom of the first exhaust gas treatment device, and a part of the first exhaust gas treatment device travels downstream along the flow of the exhaust gas.

Further, a solution of the aqueous film-forming inorganic compound is supplied in a shower form from the shower supply device provided in the second exhaust gas treatment device into the flow path of the exhaust gas, so that the aqueous solution having the increased surface area is dropped. In the solution of the film forming inorganic compound,
The dioxin precursor in the exhaust gas comes into contact with a high probability, and also here becomes a heat-resistant filter, which can efficiently capture the dioxin precursor and the powders and the like that have not been captured in the first exhaust gas treatment device. Also in this step, the phenomenon that the solution is gelled to form a film at the moment of contact with the high-temperature exhaust gas and bubbling occurs, and the dioxin precursor and the like contained in the exhaust gas are captured and included to become inclusions as described above. It is. However, since the temperature of the exhaust gas is lower than that in the first exhaust gas treatment apparatus, the bubbling phenomenon is also small, and the inclusion containing the dioxin precursor and the like is bubbled while the shower state is stably maintained. Fall with. When dioxin is partially generated, dioxin is captured and included.

Furthermore, a liquid film forming apparatus for forming a liquid film formed by the solution of the aqueous film-forming inorganic compound in the second exhaust gas treatment apparatus so as to block the flow path of the exhaust gas is provided. Since the exhaust gas passes through the liquid film of the solution of the film-forming inorganic compound, the remaining dioxin precursor and the like present in the exhaust gas are surely captured in the solution.
In addition, it is preferable that the temperature of the exhaust gas purified at the stage when the exhaust gas finally passes through the liquid film forming apparatus is controlled to be normal temperature.

According to a second aspect of the present invention, in the exhaust gas treatment apparatus according to the first aspect, the first exhaust gas treatment apparatus purifies the high-temperature exhaust gas discharged from the incinerator while cooling it. However, the exhaust gas temperature at that time is about 65
The process is controlled so that the process is performed in a temperature range not lower than 0 ° C.

According to the present invention, in the first exhaust gas treatment apparatus, since the temperature of the exhaust gas does not become approximately 650 ° C. or less, the dioxin generation reaction hardly occurs in the first place. Therefore, the dioxin precursor can be efficiently captured and removed. Here, “approximately 650 ° C.” means strictly 650 ° C.
It is used in the sense that it is not limited to, for example, 600 ° C.
If the dioxin formation reaction is unlikely to occur,
It still means good.

According to a third aspect of the present invention, in the exhaust gas treatment apparatus according to the first or second aspect, the aqueous solution supplied from the injection unit, the shower supply device, and the liquid film forming device is provided. A supply amount of the solution of the film-forming inorganic compound is controlled according to a flow rate of the exhaust gas to the first exhaust gas treatment device and the second exhaust gas treatment device. According to the present invention, since the amount of the aqueous film-forming inorganic compound solution can be increased or decreased as necessary, the exhaust gas treatment can be performed economically efficiently.

According to a fourth aspect of the present invention, in the exhaust gas treatment apparatus according to any one of the first to third aspects, the shower supply device and the liquid film forming device have a single absorption device. It is characterized in that it is provided inside the cabin. According to the present invention, for example, the solution of the aqueous film-forming inorganic compound used in the liquid film forming apparatus can be immediately reused in the shower supply device, and the aqueous film-forming inorganic compound solution can be efficiently used. It is possible to do.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the jetting unit, the shower supply device, and the liquid film forming device are supplied from the same storage tank to the aqueous forming device. A solution of a film-forming inorganic compound is supplied. ADVANTAGE OF THE INVENTION According to this invention, the solution of the aqueous film-forming inorganic compound of the same concentration can be supplied to all. As a result, the concentration of the aqueous film-forming inorganic compound solution can be easily and centrally controlled, and there is an opportunity to bring the solution having the same concentration into contact with the exhaust gas many times over the entire process following the first exhaust gas treatment process. By giving it, the dioxin precursor and the like in the exhaust gas can be gradually reduced steadily, and finally, the concentration of harmful substances can be reduced to almost zero.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the lower end of the second exhaust gas treatment device is provided with the aqueous film-forming inorganic compound after use. A collection receiving tank for receiving the solution is formed, and a component settled in the collection receiving tank is left in the collecting receiving tank at a position adjacent to the collecting receiving tank, and the supernatant of the aqueous film-forming inorganic compound solution overflowing from the collecting receiving tank is removed. A supernatant liquid receiving tank for receiving the liquid is provided. According to the present invention, the solution of the aqueous film-forming inorganic compound containing the dioxin precursor and the like is settled in the collection receiving tank, and only the reusable solution overflows from the collecting receiving tank and is in the supernatant liquid receiving tank. Accumulate in Therefore, the solution in the supernatant liquid receiving tank can be easily reused.

According to a seventh aspect of the present invention, in the sixth aspect, a device for separating the settled components out of the second exhaust gas treatment device is provided in the recovery receiving tank of the second exhaust gas treatment device. It is characterized by the following. According to the present invention, only the solution component of the aqueous film-forming inorganic compound that has captured and settled the dioxin precursor or the like can be easily separated and taken out, and then sent to a step of treating it as waste.

The invention according to claim 8 of the present application is the invention according to any one of claims 1 to 7, wherein the aqueous film-forming inorganic compound purifies exhaust gas at the lower end of the first exhaust gas treatment device. An apparatus for separating a solid portion that has been processed and dropped out of the apparatus is provided. Although the solid portion separated by this separation device contains a dioxin precursor, but hardly contains dioxin, it can be easily treated as waste.

According to a ninth aspect of the present invention, in the exhaust gas treatment apparatus according to any one of the first to eighth aspects, air is applied to the injection section of the first exhaust gas treatment apparatus. A pressurizing jetting unit that pressurizes and jets into the first exhaust gas treatment device, and is formed so as to jet the solution of the aqueous film-forming inorganic compound from the jetting unit by the jetting force of the pressurizing jetting unit. It is characterized by the following. According to the present invention, when the pressurized air is blown into the first exhaust gas treatment device from the injection unit, the exhaust gas sucked at the negative pressure is included in the foamed aqueous film-forming inorganic compound solution. The effect of increasing the effect can be brought about.

According to a tenth aspect of the present invention, in any one of the first to ninth aspects, a spiral flow is formed in the exhaust gas at the exhaust gas introduction portion of the first exhaust gas treatment device. And a guide for causing it to be provided. According to the present invention, the helical flow formed in the first exhaust gas treatment device causes a stirring action between the exhaust gas and the solution of the aqueous film-forming inorganic compound, thereby increasing the chance of contact between the exhaust gas and the solution. Increase the ability to recover dioxin precursors and the like.

[0021] The exhaust gas treatment method according to the invention of claim 11 comprises a silanol salt containing silicon (Si) as a main component and siloxane, and has a film forming property.
Exhaust gas first treatment step of injecting a solution of the aqueous film-forming inorganic compound functioning as a heat-resistant filter into the exhaust gas from an injection unit, and flow of the exhaust gas passing through the exhaust gas first treatment step of applying the aqueous film-forming inorganic compound solution. A shower supply step of supplying in the form of a shower in a path, and forming a liquid film formed by a solution of the aqueous film-forming inorganic compound so as to block a flow path of the exhaust gas that has passed through the shower supply step. A liquid film passing step so as to break through the liquid film and pass the aqueous film forming inorganic compound through the exhaust gas and the exhaust gas first treatment step, a shower supply step and a liquid film passing step sequentially. It is characterized by purifying exhaust gas.

According to the present invention, the dioxin precursor and the like in the exhaust gas can be effectively trapped and removed, similarly to the operation and effect obtained by the exhaust gas treatment apparatus according to the first aspect.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. First, the aqueous film-forming inorganic compound (hereinafter also referred to as “LC” (Liquid Ceramics)) used in the present invention will be described. This aqueous film-forming inorganic compound has been previously developed by the present inventors (Japanese Patent Publication No. 7-14).
No. 801), but a film-forming compound composed mainly of silicon (Si) and comprising a silanol salt and siloxane. More specifically, a metal aluminum or metal silicon, a mineral acid compound such as borax, boric acid, sodium fluoride or hydrofluoric acid which hydrates to dissociate boric acid or hydrofluoric acid, and an alkali metal of caustic potash, caustic soda or caustic lithium. When reacting, in water or in a solution of the mineral acid compound, a concentrated solution reaction between the metal solid and the alkali metal is caused, and further reacting the mineral acid compound,
While controlling the reaction heat within 50 ° C or higher and within 100 ° C,
It is an inorganic compound having a film forming property with the specific gravity of the product being 1.1 or more.

This aqueous film-forming inorganic compound has heat resistance in any temperature range of exhaust gas from an incinerator in a temperature range of 200 to 1000 ° C. and does not decompose. The aqueous film-forming inorganic compound has an intumescent property and forms a solid-phase precursor at a high temperature to form a film.
If the retained water evaporates, a bubbling phenomenon occurs. The aqueous film-forming inorganic compound shows a foaming phenomenon when a liquid having a solid content of 50% is applied to an iron plate and heated from below or from above. This phenomenon continues up to 650 ° C., and as the heating temperature rises, the foaming and bubbling disappear, forming a paste and forming a coating.

It has been confirmed with a high-temperature microscope that the aqueous film-forming inorganic compound is bubbled by the exhaust gas, forms a coating film to form a filter, and discharges only a purification processing gas such as water vapor or carbon dioxide gas. When the inorganic compound reaches room temperature, the exhaust gas residue can be included in the coating film. By such an action, the aqueous film-forming inorganic compound has an action as a heat-resistant filter. Since the aqueous film-forming inorganic compound is a ceramic, even if the exhaust gas is at a high temperature of 800 ° C,
Even if it fluctuates to a low temperature of 200 ° C., without burning, black smoke, malodor, dioxin precursor and fly ash can be included in the bubble.

Also, heavy metals in exhaust gas can be captured by ionic bonding. That is, the aqueous film-forming inorganic compound becomes in the form of -Si-OM (M is a metal) during the high-temperature treatment, and is insolubilized by ionic bonding with heavy metals such as Pb, Zn, As, Cr, and Ce.

The aqueous film-forming inorganic compound is in the form of a colloid having a particle size of 0.5 to 1 μm.
When the nozzle is turned into powder by a spray drier when the nozzle temperature is 180 ° C. with the heated gas, a foamed balloon having a size of 50 to 80 μm is formed. It is considered that when the aqueous film-forming inorganic compound is heated in the presence of excess water, film-forming foaming occurs, the surface is gelled, the solid content of the waste is included by the filter action, and the residue is deposited. By such a filter action, volatile hydrochloric acid and chloride in high-temperature exhaust gas are also included in the aqueous film-forming inorganic compound. Then, the (silanol) Na salt of the aqueous film-forming inorganic compound is combined with chlorine as a dioxin precursor to form NaCl, and SiH ₃ of the siloxane reacts quickly with chlorine, and chlorine at high temperature before becoming dioxin. Therefore, dioxin is not generated even when cooled to 200 ° C. to 650 ° C. where dioxin is easily generated.

When the aqueous film-forming inorganic compound is sprayed into a high-temperature exhaust gas of 200 ° C. or higher, it instantaneously gels and foams to form a film, and contains black smoke and odorous gas. The gelled colloidal substance has a filter action.

Since the spraying means requires instantaneous spreading, a negative pressure sufficient for suction is generated by spraying using an ejector which generates a high pressure, and the exhaust gas is converted into a film-forming foam of an aqueous film-forming inorganic compound. A gelled residue is included, including fly ash, which is pumped and deposited with a specific gravity difference, and only water vapor evaporates. A similar effect is produced by spraying the exhaust gas blown by the blower under pressure or by dripping the exhaust gas blown. The method of contacting the aqueous film-forming inorganic compound with the exhaust gas is such that the aqueous film-forming inorganic compound is sprayed or dropped onto the exhaust gas sucked or blown, and conversely, the aqueous film-forming inorganic compound has a high temperature. It has been confirmed that even when the exhaust gas is blown in and brought into contact, the effect of film-forming foaming and inclusion of the residue is the same.

An aqueous film-forming inorganic compound can be easily mixed with waste containing organic substances, heavy metals, soil, moisture and the like.
When organic matter is burned, the aqueous film-forming inorganic compound mixed with the organic matter is foamed to form a film and contains the combustion gas, and captures carbonized and gasified soot and Cl gas to pass only water vapor. It acts as a heat resistant filter and is simultaneously mixed with the bottom ash.

Here, it will be specifically described that the above-mentioned aqueous film-forming inorganic compound, ie, LC, has an ability to simultaneously purify dioxin precursors, dioxins, black smoke and dust in high-temperature exhaust gas (Japanese Patent Application No. Hei 10-284). No. 11-3050). This LC is an inorganic polymer having a high molecular weight of 5,000 or more as compared with a water glass of 140 or less when the weight average molecular weight is measured. Therefore, the LC is H
+ Cl = Equimolar reaction like HCl but chlorine Cl
Has the function of capturing many moles of LC is
It has a function of trapping and reacting chlorine Cl even at a high temperature of 600 to 800 degrees.

The component of LC is a silanol salt [Si.H_nOH_4-n]_pM_m  And siloxane [H₃Si-O-SiH₃]_q  It is. Here, M represents an alkali metal, and n, p,
m and q represent the number of moles. As is clear from this,
LC reacts with chlorine Cl in a large number of M, H, Si
It has a reactive group.

Further, an organic bond of chlorine Cl (100 kca
1 / mol or less), the chlorine (Cl) does not form an organic bond even at a temperature of 450 ° C. or less, and thus the reactive bond with the LC is performed even at a temperature of 450 ° C. or less. Is presumed to occur.

According to the results of the experiment, 650 to 8
Even if dioxin of 200 to 350 ng / TEQ is generated at the entrance of the cylindrical body in which the exhaust gas of 00 degrees is reduced to 350 degrees, the LC liquid (specific gravity 1.5 and pH 12.2) of 50
When spraying the double-thinning liquid so as to fill the inside of the cylinder in the form of a mist, 1.7 ng of 1% or less of the generated dioxin
Weight was reduced by / TEQ.

Also, 900 ng / TEQ of dioxin, which is extremely large at an exhaust gas temperature of 600 to 700 ° C., is generated, an LC liquid having a specific gravity of 1.4 and a pH of 12 is diluted 50 times, sprayed onto the exhaust gas, circulated and circulated. Even when was reused, the amount of generated dioxin could be reduced to about 1%. From the experience of the above experiments, the exhaust gas treatment apparatus according to the present invention is one in which exhaust gas and LC are contacted three times in multiple stages.

The present exhaust gas treatment apparatus sprays exhaust gas at 600 to 800 degrees with an LC liquid also for cooling, captures the dioxin precursor in the evaporated and dried LC, and further reduces the Loxin in the next step.
The liquid C is shower-sprayed on the exhaust gas, and then the exhaust gas and the LC liquid are contacted three times, followed by bubbling, and it goes without saying that this apparatus shows results higher than the above experimental results.

In the above experimental results, the circulating water of the LC was pH 12, but after a long operation, the pH became 1
1 and further to pH 10. In other words, it is obtained by capturing the chlorine gas decomposed by dioxin and lowering the pH. At the same time, the LC liquid became black as it absorbed black smoke over time. As a result, the outlet exhaust gas was colorless. In this experiment, solid fuel (RDF) 70, by weight ratio, so as to easily generate dioxin, black smoke and bad smell,
A mixture of 7.5 of vinyl chloride and 22.5 of polyethylene was used, but no odor was generated from the outlet when the vinyl chloride was burned.

In this experiment, when the LC used in the present invention was not used, the pH of the circulating water was 3, and the pH was 2
Until it became strong acid water. Of course, the exhaust gas at the outlet made breathing difficult, and the roof was blackened with soot.

From the above, it is possible to spray the LC liquid on the high-temperature exhaust gas, spray-wash the LC liquid on the low-temperature exhaust gas whose exhaust gas temperature has been lowered, and further perform bubbling cleaning with a liquid film of the LC liquid. It can be easily estimated that the result is equivalent to the complete processing.

Experimental Apparatus Prior to the design of the exhaust gas treatment apparatus, an experimental apparatus of a three-stage treatment shown in FIG. 4 was installed. Although dioxin and generated hydrochloric acid are not in an absolute proportional relationship but have a correlation, exhaust gas in each stage was collected in water, and its chlorine concentration and acidity pH were measured. As a result, the Cl of the exhaust gas after the first stage treatment was 1100 mg / Nm ³ and the pH was 3.2.
The Cl of the exhaust gas after the second stage treatment is 250 mg / Nm
^The pH of the exhaust gas after the third stage treatment is 6.3.
At 2 mg / Nm ³ the pH was 7. From the above, it can be estimated that dioxin generated from high-temperature exhaust gas can be almost completely treated.

The present invention uses the above-mentioned aqueous film-forming inorganic compound solution to reliably and efficiently capture dioxin precursors and the like in the exhaust gas treatment step of an incinerator, thereby preventing the generation of dioxin. And a device for effectively preventing the generation of dioxin in an exhaust gas treatment process.

FIG. 1 shows a system diagram of an exhaust gas treatment apparatus 1 according to an embodiment of the present invention in an exhaust gas treatment step of an incinerator. In FIG. 1, reference numeral 3 denotes a gas cooling chamber serving as a first exhaust gas treatment device, which is a refuse incinerator (not shown).
Is provided for cooling and purifying the high temperature exhaust gas of about 800 ° C. generated in the above. A gas introduction pipe 5 connected to the incinerator is connected to the upper part of the gas cooling chamber 3, and the exhaust gas introduced therefrom is spirally circulated by a spiral guide 2 formed in the upper part of the gas cooling chamber 3. And a gas outlet 7 formed below the gas cooling chamber 3.
The temperature of the exhaust gas is cooled to about 450 ° C. as an example between the time when the exhaust gas is discharged to the next step.
The temperature may be 400 ° C. or another temperature.

In the upper part of the gas cooling chamber 3, there is provided an LC injection nozzle 9 which is an injection part for spraying and supplying an aqueous solution of an aqueous film-forming inorganic compound (LC), that is, an aqueous LC solution into the gas cooling chamber 3. ing. The LC injection nozzle 9 is connected to the LC supply line 13, and an LC storage tank 15 is provided upstream of the LC supply line 13. The LC aqueous solution is supplied to the LC supply pump 17 through the LC filter 19 on the way.
Thus, the liquid can be supplied to the LC injection nozzle 9. The LC aqueous solution is diluted by 50 times or more with water in the measuring tank 21, and is appropriately supplied to the LC storage tank 15.

The LC aqueous solution injected from the LC injection nozzle 9 is jetted into a high-temperature exhaust gas at about 800 ° C., so that it instantaneously foams to form a gel-forming film. Most of the harmful gas components including bad smells, heavy metals, fly ash, dioxin precursors, etc. are included. Also, LC
The supply amount of the LC aqueous solution injected from the injection nozzle 9 is set to such an extent that it fills the exhaust gas flow path in the gas cooling chamber 3 by the above-mentioned bubble boiling. The exhaust gas is cooled by the injection of the LC aqueous solution, and the temperature of the exhaust gas is reduced at the gas discharge port 7 of the gas cooling chamber 3 to about 450 ° C.

Immediately upstream of the injection nozzle 9, there is provided a pressurized air introduction unit 11 for introducing pressurized air into the gas cooling chamber 3 together with the LC aqueous solution. Pressurized air introduction unit 11
Is blown into the gas cooling chamber 3 to increase the effect that the exhaust gas sucked by the negative pressure based on the blower 64 described later is included in the foamed LC aqueous solution. Can be brought.

An inclusion storage portion 23 is formed at the bottom of the gas cooling chamber 3. The inclusion storage portion 23 contains a dioxin precursor, heavy metal and the like in the exhaust gas when the LC is formed into a film. Are temporarily stored. Here, the inclusions are dried and granulated as moisture evaporates due to the high-temperature exhaust gas. The powder (particles) temporarily stored in the inclusion storage section 23 is discharged to a dust receiving tank 27 via a discharge gate valve 25, and finally packed in a drum 29.

Next, the exhaust gas discharged from the gas cooling chamber 3 passes through the line 8 and reaches the absorption tower 30, which is the next second exhaust gas treatment device. The absorption tower 30 is a device for further removing and purifying harmful gas components such as black smoke, foul odor, heavy metals, fly ash, dioxin precursor and partially generated dioxin in exhaust gas.

As shown in FIG. 3, a plurality of shower trays 31 are formed in the middle stage of the absorption tower 30 so as to alternately protrude from both sides of the inner wall of the absorption tower 30. Above 31, an LC supply nozzle 33 is provided. The LC supply nozzle 33 is connected to a first branch pipe 35 that branches off from the LC supply line 13,
The aqueous LC solution in the storage tank 15 is supplied to the uppermost shower tray 31.

A plurality of holes are formed in each shower tray 31, and the aqueous LC solution supplied to the uppermost shower tray 31 sequentially falls downward from the holes of each shower tray in a shower shape. I have. Note that the LC aqueous solution may slightly overflow from the upper shower tray and flow down onto the lower shower tray.
A receiving tray 37 having no hole is provided at the lowermost portion of the shower tray 31, and the lower end of a guide tube 39 extending downward from substantially the center thereof is formed by a partition plate 40 at the lowermost portion of the absorption tower 30. Into the receiving tank 41.

The exhaust gas cooled in the gas cooling chamber 3 enters the absorption tower 30 from below the absorption tower 30 and rises upward so as to sew between the shower trays 31. In the process, since the liquid and the shower-like LC aqueous solution falling from each shower tray 31 come into gas-liquid contact, black smoke, odor, heavy metal, fly ash, dioxin precursor, etc. in the exhaust gas are included in the LC aqueous solution. Here, too, the LC aqueous solution is at a high temperature (about 450 ° C.
(00 ° C.), the same phenomenon as described above occurs in which the film is gelled and foamed at the moment of contact with the exhaust gas, and the dioxin precursor and the like contained in the exhaust gas are captured and included to become inclusions. However, since the temperature of the exhaust gas is lower than that in the first exhaust gas treatment device 3, the bubbling phenomenon is also small, and the inclusion including the dioxin precursor and the like is bubbled while the shower state is stably maintained. Fall with shower. When dioxin is partially generated, dioxin is captured and included.

The aqueous LC solution which has dropped from the multi-stage shower tray 31 in a shower shape falls onto the receiving tray 37 in such a manner as to contain the dioxin precursor and the like in the exhaust gas. Then, from there, it accumulates in the LC recovery receiving tank 41 via the guide tube 39, where insolubles containing the dioxin precursor and the like precipitate downward, and the LC supernatant liquid overflows the partition plate 40, and the next supernatant liquid It temporarily accumulates in the receiving tank 43. When a predetermined amount or more of the insoluble matter settled in the LC recovery receiving tank 41 is collected, the insoluble matter is discharged to an LC waste liquid receiving tank 44 connected to the lower end of the absorption tower 30 as shown in FIG. In the present embodiment, the LC supernatant stored in the supernatant liquid receiving tank 43 passes through the LC circulation pipe 45 in the LC storage tank 15.
Has been returned to use again.

As shown in FIG. 3, a plurality of perforated trays 47 are formed in the upper part of the absorption tower 30 so as to alternately protrude from both sides of the inner wall of the absorption tower. The LC supply nozzle 49 is provided above. The LC supply nozzle 49 is connected to a second branch pipe 51 that branches off from the LC supply pipe 13, and is connected to the LC storage tank 15.
Is supplied to the uppermost perforated tray 47.

Each of the perforated trays 47 is provided with a downwardly extending closing plate 53, which extends to a position approaching the perforated tray 47 immediately below. Each of the perforated trays 47 has a plurality of small holes including the closing plate 53. L supplied from the LC supply nozzle 49
The C aqueous solution is present on the perforated tray 47 in a thin liquid film state so as to close these holes, and is configured to overflow gradually from the upper stage to the lower stage.

For this reason, the exhaust gas that has passed through the multi-stage shower tray 31 tends to break the liquid film of the aqueous LC solution from the small holes of the perforated tray 47 and escape upward. Therefore, the exhaust gas must pass through the LC aqueous solution without fail. At this time, dioxin precursors, heavy metals, and the like that have not been removed by the shower with the shower tray 31 are included in the LC liquid film and almost completely removed.

An annular chimney tray 55 is formed between the lowermost perforated tray 47 and the uppermost shower tray 31. A discharge pipe 57 is formed downward from a part of the chimney tray 55, and its lower end extends into the uppermost shower tray 31. That is, the LC aqueous solution supplied to the perforated tray 47 is temporarily stored in the chimney tray 55, and then is supplied to the shower tray 31 via the discharge pipe 57, where it is re-used as an LC aqueous solution for showering. It is being used.

The lower end of the closing plate 53 formed on the lowermost perforated tray 47 extends below (inside) the LC level of the chimney tray 55. That is, the lower end of the closing plate 53 is always located below the upper surface of the LC aqueous solution collected in the chimney tray 55. By adopting such a configuration, the exhaust gas that has passed through the shower tray 31 passes through the chimney tray 55, and then all of the exhaust gas passes through the perforated tray 4.
7, and is guided downstream. This is similar to blowing and contacting the exhaust gas into the LC aqueous solution, and when the exhaust gas passes through the LC aqueous solution, the dioxin precursor or heavy metal that is not removed by the shower with the shower tray 31 is included by the LC, Almost completely removed.

As described above, the exhaust gas that has passed through the chimney tray 55 passes through the holes of the first-stage perforated tray 47 and then passes through the holes of the second- and subsequent-stage perforated trays 47. The mist of the aqueous LC solution is removed. Thereafter, the water passes through the exhaust pipe 61 from the upper part of the absorption tower 30 and is separated into water by an exhaust gas KO (knockout) drum 63 in the middle thereof, and then released into the atmosphere.

In the above embodiment, the gas cooling chamber 3
The amount of the aqueous LC solution injected from the LC injection nozzle 9 and the amount of the aqueous LC solution supplied from each of the LC supply nozzles 33 and 49 in the absorption tower 30 are always appropriate in accordance with the flow rate and temperature of the exhaust gas. Is controlled as follows.

The operation of the exhaust gas treatment apparatus according to the above embodiment will be described. First, when the LC aqueous solution is injected from the injection nozzle 9 into the gas cooling chamber 3, the LC aqueous solution contacts the high-temperature exhaust gas to form a gel and form a bubble.
The dioxin precursor filled in the exhaust gas channel and contained in the exhaust gas, as well as foul odor components, black smoke and heavy metals are captured and contained as a heat-resistant filter. When dioxin is partially generated, dioxin is captured and included. Further, by supplying the LC aqueous solution into the gas cooling chamber 3, an effect of cooling the exhaust gas can be obtained. In the process of contacting with high-temperature exhaust gas and bubbling to capture the dioxin precursor and the like, the LC aqueous solution is dried by evaporating the water content, and the inclusion including the dioxin precursor and the like is powdered (solid portion). As a result, it is separated from the exhaust gas channel and falls to the bottom of the gas cooling chamber 3.

Further, by supplying the aqueous solution of LC from the shower tray 31 provided in the second exhaust gas treatment apparatus into the flow path of the exhaust gas in the form of a shower, the LC aqueous solution whose surface area is increased by dripping is reduced. The dioxin precursor comes into contact with a high probability, and the dioxin precursor and the like that are not captured in the gas cooling chamber 3 can be efficiently captured. Here, too, the phenomenon that the LC aqueous solution comes into contact with the high-temperature exhaust gas to form a gel and form a bubble and to capture and include the dioxin precursor and the like contained in the exhaust gas is the same as described above. is there. However, as the temperature of the exhaust gas is lower than that in the gas cooling chamber 3, the bubbling phenomenon is also small,
While the shower state is maintained stably, the bubbles boil and the inclusions including the dioxin precursor and the like fall with the shower. When dioxin is partially generated, dioxin is captured and included.

Furthermore, since the exhaust gas passes through the liquid film of the LC aqueous solution formed on the perforated tray 47 provided in the second exhaust gas treatment apparatus, the remaining dioxin precursor present in the exhaust gas is reduced. Reliably trapped in the aqueous LC solution. The temperature of the exhaust gas that has been purified at the stage when it has finally passed through the perforated tray 47 is controlled to be normal temperature.
4 to the atmosphere.

In the above-described embodiment, the shower tray 31 and the perforated tray 47 are provided in one absorption tower 30, but this is for improving the circulation of the LC aqueous solution and performing efficient exhaust gas treatment. And for the purpose of cost reduction. However, in the present invention, the shower tray 3
1 and the perforated tray 47 can be installed separately in separate absorption towers.

In the above embodiment, each of the LC injection nozzles 9 in the gas cooling chamber 3 and each L
The aqueous LC solutions supplied to the C supply nozzles 33 and 49 are all branched and supplied from the same supply source (LC storage tank 15). This means that the LC supply liquids having the same concentration are all supplied. By adopting such a method, the concentration control of the LC supply liquid can be easily and centrally performed, and the LC aqueous solution having the same concentration is cooled in the cooling step (first step).
From the exhaust gas treatment process) to the absorption process (shower process and liquid film passing process), by giving opportunities to contact the exhaust gas many times, the harmful substances such as dioxin precursors in the exhaust gas are gradually reduced steadily. Finally, the harmful substances can be brought close to a concentration close to zero.

[0064]

According to the present invention, a film-forming heat-resistant filter made of a solution of an aqueous film-forming inorganic compound is applied to an exhaust gas treatment step of an incinerator, so that a dioxin precursor is removed in advance to generate dioxin. Can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a system diagram of an exhaust gas treatment apparatus according to the present invention used in an exhaust gas treatment step of an incinerator.

FIG. 2 is a longitudinal sectional view showing a gas cooling chamber constituting the exhaust gas treatment apparatus according to the present invention.

FIG. 3 is a schematic longitudinal sectional view showing a shower supply device and a liquid film forming device constituting the exhaust gas treatment device according to the present invention.

FIG. 4 shows a block diagram of a configuration of an experimental apparatus performed prior to the design of an exhaust gas treatment apparatus according to the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 exhaust gas treatment device 3 first exhaust gas treatment device (gas cooling chamber) 9 injection unit (LC injection nozzle) 11 pressurized air introduction unit 13 LC supply line 15 LC storage tank 17 LC supply pump 23 LC storage unit 27 dust receiving tank 29 drum can Reference Signs List 30 second exhaust gas treatment device (absorption tower) 31 shower tray 33 LC supply nozzle 35 first branch pipe 37 receiving tray 39 guide pipe 40 partition plate 41 LC recovery receiving tank 43 supernatant liquid receiving tank 45 LC circulation pipeline 47 perforated tray 49 LC supply Nozzle 51 Second branch pipe 53 Closure plate 55 Chimney tray 57 Discharge pipe 59 Mist removal device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Kanada 5-20-6 Motomura, Chigasaki-shi, Kanagawa Prefecture (72) Inventor Nobuyuki Ashi 1-27-5, Nihonbashi-Kakigashi-cho, Chuo-ku, Tokyo Inami Corporation F term (reference) 3K078 AA06 BA03 CA24 4D002 AA19 AA21 AA28 AC04 BA02 BA03 BA13 BA14 BA16 CA01 CA07 CA11 DA70 EA02 EA13 GA01 GA02 GA03 GB01 GB02 GB03 GB04 GB09 HA10

Claims (11)

[Claims] 1. An exhaust gas treatment device comprising: a first exhaust gas treatment device; and a second exhaust gas treatment device disposed subsequent to the first exhaust gas treatment device, wherein the first exhaust gas treatment device contains silicon (Si) as a main component. , Comprising a silanol salt and siloxane, having a film forming property, and configured to inject a solution of an aqueous film forming inorganic compound that functions as a heat resistant filter into exhaust gas from an injection unit. A shower supply device for supplying a solution of the aqueous film-forming inorganic compound into the flow path of the exhaust gas in a shower, and a liquid film formed by the solution of the aqueous film-forming inorganic compound flowing through the flow path of the exhaust gas. A liquid film forming device formed so as to block and allow the exhaust gas to break through the liquid film and pass therethrough, wherein the aqueous film-forming inorganic compound comprises the exhaust gas, the first exhaust gas treatment device, and the second exhaust gas. processing An exhaust gas treatment device characterized in that exhaust gas is purified by contacting the exhaust gas in stages. 2. The first exhaust gas treatment device according to claim 1, wherein the first exhaust gas treatment device performs a purification treatment while cooling the high-temperature exhaust gas discharged from the incinerator, but in a temperature region where the exhaust gas temperature does not become approximately 650 ° C. or less. An exhaust gas treatment device controlled to perform treatment. 3. The first exhaust gas treatment apparatus according to claim 1, wherein the supply amount of the aqueous film-forming inorganic compound solution supplied from the jetting unit, the shower supply device, and the liquid film formation device is the first exhaust gas treatment device. And an exhaust gas treatment device controlled in accordance with the flow rate of exhaust gas to the second exhaust gas treatment device. 4. The apparatus according to claim 1, wherein the shower supply device and the liquid film forming device include:
An exhaust gas treatment device provided in a single absorption tower. 5. The aqueous film-forming inorganic compound solution according to claim 1, wherein the jetting unit, the shower supply device, and the liquid film forming device are supplied from the same storage tank. An exhaust gas treatment device characterized by the above-mentioned. 6. A collection tank for receiving a used aqueous film-forming inorganic compound solution at a lower end of the second exhaust gas treatment device according to any one of claims 1 to 5, At a position adjacent to the collection receiving tank, a supernatant liquid receiving tank is provided which receives the supernatant liquid of the aqueous film-forming inorganic compound solution which has left the components settled in the collection receiving tank and overflows from the collection receiving tank. An exhaust gas treatment device characterized by the above-mentioned. 7. The exhaust gas treatment device according to claim 6, wherein a device for separating the settled component out of the device is provided in the recovery receiving tank of the second exhaust gas treatment device. 8. The solid part in which the aqueous film-forming inorganic compound is subjected to a purification treatment of an exhaust gas to drop a solid portion at a lower end portion of the first exhaust gas treatment apparatus outside the apparatus. An exhaust gas treatment device comprising a device for separating the waste gas from the waste gas. 9. The method according to claim 1, wherein:
The injection unit of the first exhaust gas treatment device includes a pressurized injection unit that pressurizes air and injects the air into the first exhaust gas treatment device. An exhaust gas treatment apparatus formed so as to spray a solution of a film forming inorganic compound. 10. The exhaust gas introduction section of the first exhaust gas treatment device according to claim 1, wherein a guide for forming a spiral flow in the exhaust gas is provided. Waste gas treatment equipment. 11. A solution of an aqueous film-forming inorganic compound which comprises a silanol salt containing silicon (Si) as a main component and siloxane and has a film-forming property and functions as a heat-resistant filter is discharged from an injection section into an exhaust gas. An exhaust gas first treatment step of injecting the aqueous film-forming inorganic compound, a shower supply step of supplying a solution of the aqueous film-forming inorganic compound in a flow path of the exhaust gas having passed through the exhaust gas first treatment step, A liquid film passing step in which a liquid film formed by the solution of the compound is formed so as to block the flow path of the exhaust gas that has passed through the shower supply step, so that the exhaust gas breaks through the liquid film and passes therethrough. An exhaust gas purifying method, wherein the aqueous film-forming inorganic compound purifies the exhaust gas through the exhaust gas and the exhaust gas first treatment step, a shower supply step, and a liquid film passing step sequentially.