JP4456298B2 - Pollutant detoxification equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pollutant detoxifying device that can efficiently detoxify pollutants such as dioxins.
[0002]
[Prior art and problems to be solved by the invention]
Dioxins and other environmental pollutants have been pointed out to be endocrine disruptors (so-called environmental hormones) in recent years, as well as chronic toxicity to the human body, fetal toxicity, teratogenicity, and carcinogenicity. , Has become a big social problem. Sources of dioxins include PCB, chlorophenol or herbicide impurities, municipal waste incineration, automobile exhaust, use of chlorine in sewage sludge treatment, etc., many of which originate from the combustion process by waste incineration .
[0003]
Conventionally, as a technology for suppressing the generation of dioxin or a technology for detoxifying the generated dioxin,
a) A complete combustion method that suppresses the generation of dioxins by maintaining the combustion gas during incineration in a well-mixed combustion chamber in a high-temperature atmosphere of 800 ° C. or higher,
b) a thermal decomposition method in which dioxins are dechlorinated and hydrogenated by heating in a low oxygen atmosphere;
c) A method of decomposing dioxin with supercritical water is known.
[0004]
However, in the method a), it is difficult to make the gas in the combustion chamber uniform and keep the gas residence time long, and in the method b), if the reaction is not performed in a low oxygen atmosphere, dioxins are conversely formed. There is a problem of being generated. On the other hand, although the method c) is the most expected method without such problems, it is difficult to make 100% harmless with this method.
[0005]
The present invention has been devised in view of the above-described problems, and decomposes the contaminants by supercriticalizing the liquid in the treatment liquid containing the contaminants, and remains in the treatment liquid. The objective is to provide a pollutant detoxifying device that can exhibit a higher ability to decompose pollutants than before, based on the fact that the pollutants to be injected are further injected into the furnace body and thermally decomposed in the furnace body. Yes.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 of the present invention is a furnace body to which a heating burner is attached and which is a high-temperature space of 800 ° C. or more, and a treatment liquid containing a contaminant and a liquid is allowed to flow and disposed inside the furnace body. And a heat exchange flow path having a heat exchanger composed of a tubular body that circulates in a spiral, and a feeding unit that injects the treatment liquid that has passed through the heat exchange flow path into the furnace body, The heat exchanger comprises a cylindrical base portion to which the heating burner is attached, and a tip portion that is connected to one end side of the cylindrical base portion and in which the heat exchanger is disposed. In the flow path, the contaminants are decomposed by supercriticalizing the liquid in the treatment liquid, and the contaminants remaining in the treatment liquid are jetted into the furnace body and thermally decomposed in the furnace body. It is a feature.
[0007]
The invention according to claim 2 is the pollutant detoxifying device according to claim 1, wherein the liquid is water and the treatment liquid contains fuel.
[0008]
The invention according to claim 3 is characterized in that the feeding section includes a nozzle capable of injecting a treatment liquid into the furnace body, and the nozzle is provided with a cooling means for cooling the nozzle. Item 3. The pollutant detoxifying device according to Item 1 or 2.
[0009]
The invention according to claim 4 is characterized in that the furnace body is provided with an air supply port for burning fuel supplied to the furnace body by supplying air to the furnace body. 3. The pollutant detoxifying device according to any one of 3 above. The invention described in claim 5 is the pollutant detoxifying device according to any one of claims 2 to 4, wherein the fuel contained in the treatment liquid is A heavy oil.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a schematic cross-sectional view of the pollutant detoxification apparatus 1 of the present invention. In FIG. 1 , a pollutant detoxifying device 1 is provided with a furnace body 2 that becomes a high-temperature space A of 800 ° C. or higher, a treatment liquid D containing pollutants and a liquid, and is disposed inside the furnace body 2 and spirals. A heat exchange flow path 3 having a heat exchanger 7 composed of a tubular body that circulates in the air, and a feed unit 4 that injects the treatment liquid that has passed through the heat exchange flow path 3 into the furnace body 2.
[0011]
The furnace body 2 is formed by molding and solidifying a material having excellent heat resistance, for example, heat-resistant clay. Further, in this example, the furnace body 2 is composed of a cylindrical base portion 2a to which a heating burner 5 is attached, and a tip portion 2b connected to one end side of the cylindrical base portion 2a. Show.
[0012]
In this example, an opening O1 is formed on one side of the base 2a, and the flame of the burner 5 is blown out from the opening O1 into the base 2a. Combustion air is supplied to the burner 5 from the fan Ba through the flow path L1, the branch portion V1, and the flow path L2. Further, fuel is supplied to the burner 5 (not shown). By this burner 5, the interior of the furnace body 2 can be maintained in a high-temperature space A of 800 ° C. or higher, more preferably 800 to 1000 ° C. The other end side of the base 2a is closed by a wall 2d. The tip 2b of the furnace body 2 is formed in a cylindrical shape having a smaller diameter than the base 2 in this example, and has an opening 2c on the side opposite to the base 2a. The opening 2c may be provided with equipment for taking out the heat energy of the furnace body 2 as appropriate.
[0013]
In the present embodiment, the air supply port O3 is intermittently formed on the outer periphery of the furnace body 2 in the circumferential direction. In this example, the air supply port O3 is illustrated as extending obliquely toward the distal end portion 2b. A ring member 17 having a circumferential groove extending in the circumferential direction is attached to the air supply port O3. The ring member 17 is supplied with compressed air from the fan Bb via the flow path L5. Therefore, by driving the fan Bb, fresh air can be supplied to the inside of the furnace body 2 and toward the tip portion 2a.
[0014]
In the present example, the heat exchange flow path 3 includes a first flow path 6, the heat exchanger 7, and a second flow path 8.
[0015]
One end of the first flow path 6 communicates with the processing liquid tank Ta that stores the processing liquid D, and the other end 6 </ b> A is connected to a heat exchanger 7 disposed inside the furnace body 2. Further, the first flow path 6 can suck the processing liquid from the processing liquid tank Ta and discharge it to the heat exchanger 7 by interposing the pump 9.
[0016]
In this example, the treatment liquid is prepared by mixing at least a contaminant such as dioxin or PCB and water as a liquid. In this example, fuel is also mixed in addition to these. The contaminant is stored in the auxiliary tank Tb, and the auxiliary tank Tb communicates with the processing liquid tank Ta via the flow path 12 and the on-off valve V2. The contaminant is stored as, for example, a liquid or a powdery substance, and a predetermined amount can be introduced into the processing liquid tank Ta by operating the on-off valve V2. In the treatment liquid tank Ta, a stirring blade 11 that can be rotationally driven by the electric motor 11 is arranged in the vicinity of the bottom, so that contaminants and water can be uniformly stirred and mixed in the treatment liquid tank Ta. The mixing ratio of water and contaminants is preferably 5 to 15% by weight, more preferably 10 to 15% by weight with respect to 100% by weight of water.
[0017]
In this example, the treatment liquid tank Ta is provided with the liquid level detector 13. In this example, the liquid level detector 13 includes a float F and a limit switch LS that can detect the upper limit height and the lower limit height of the float F, respectively. When the limit switch LS detects the lower limit height of the float F, water and fuel are appropriately supplied to the processing liquid tank Ta by a control device (not shown), and the on-off valve V2 is opened and closed for a predetermined time. A contaminant is introduced into the processing liquid tank Ta. Further, when the limit switch LS detects the upper limit height of the float, these supplies are stopped. Thereby, a substantially constant amount of processing liquid can be continuously prepared in the processing liquid tank Ta. In addition, although the fuel is contained in the process liquid of this example, this is mentioned later.
[0018]
In this example, the heat exchanger 7 is disposed inside the front end portion 2b of the furnace body 2 and is formed of a tube that spirals around the front end portion 2b. The treatment liquid flowing through the heat exchanger 7 can be heated to a high temperature by receiving thermal energy from the high temperature space A of the furnace body 2 through the tube body. In this example, the treatment liquid can be heated to, for example, 400 ° C. or higher in the heat exchanger 7.
[0019]
Further, the second flow path 8 exemplifies one in which one end 8A is connected to the heat exchanger 7 and the other end is connected to the feeding unit 4 including the injection nozzle N through the outside of the furnace body 2. ing. The second flow path 8 is provided with a pressure gauge 13 that can detect the pressure inside the heat exchange flow path 3 and a thermometer 14 that can detect the temperature of the processing liquid in the heat exchange flow path 3. ing. One end 8A of the second flow path 8 and the other end 6A of the first flow path 6 are connected to the heat exchanger 7 by a joint outside the furnace body 2, respectively. The heat exchanger 7 removes the joint in accordance with the detoxifying pollutant and the treatment liquid, and replaces the pipe with a pipe having a different length, inner diameter, helical diameter, helical pitch, etc. The heating temperature can be adjusted as appropriate.
[0020]
The feeding unit 4 is composed of an injection nozzle N in this example. The jet nozzle N is supplied with compressed air. The compressed air is supplied from the fan Ba through the flow path L1, the branch portion V1, and the flow path L3. This compressed air also serves as a cooling means for cooling the injection nozzle N. This helps to reduce the thermal fatigue of the injection nozzle N and improve the durability.
[0021]
The operation of the pollutant detoxifying device 1 of the present embodiment configured as described above will be described. First, the interior of the furnace body 2 is heated to a high temperature space A of 800 ° C. or higher by igniting the burner 5. Next, the processing liquid D prepared in the processing liquid tank Ta is driven into the heat exchange flow path 3, that is, the first flow path 6, the heat exchanger 7, and the second flow path 8 by driving the pump 9. Discharge. The injection nozzle N is closed at this stage.
[0022]
The treatment liquid in the heat exchange flow path 3 is heated by exchanging heat in the heat exchanger 7 disposed in the high temperature furnace body 2. Further, by setting the discharge pressure of the pump 9, the inside of the heat exchange channel 3 is kept at a high pressure, and the liquid of the processing liquid (water in this example) is supercritical in the heat exchange channel 3. Water becomes liquid at normal temperature and becomes vapor (gasification) at 100 ° C. under atmospheric pressure. However, when the pressure is above a certain pressure and above a certain temperature, the density of water vapor compressed at high pressure and the density of thermally expanded water are reduced. It becomes the same state that is indistinguishable from liquid and gas, that is, a supercritical state, and water in such a state is called supercritical water. In order to make water supercritical, it may be heated to 374 ° C. or higher under a high pressure of 22.12 MPa or higher. The temperature and pressure of the treatment liquid in the heat exchange channel can be monitored and appropriately adjusted by a thermometer 13 and a pressure gauge 14 provided in the second channel 8.
[0023]
Supercritical water has a dielectric constant of 2 to 30, which is lower than water at normal temperature and pressure. For this reason, organic substances, such as dioxin, can be dissolved. Supercritical water has an ion product of about 10 ⁻¹¹ to 10 ⁻¹² (mol / l) ^2, and 10 to 100 times as many water molecules as room temperature and normal pressure are dissociated into ions. Accordingly, an acid / alkali catalytic effect is imparted to water itself, and dioxins can be hydrolyzed and dechlorinated. Supercritical water completely dissolves with organic substances such as oil and gases such as oxygen. Thereby, about dioxin, since water, oxygen, and dioxin become all a uniform phase, dioxin can be oxidatively decomposed instantaneously.
[0024]
As described above, in the heat exchange flow path 3, the water in the treatment liquid is supercritical, so that the pollutant, particularly dioxin, can be decomposed (detoxified) at a ratio of about 95 to 97%. . Such a decomposition process is desirably performed for about 10 to 15 minutes, for example. In addition, after the detoxification process with supercritical water, the spray nozzle N is opened, so that the treatment liquid inside the heat exchange channel 3 is sprayed from the spray nozzle N to the furnace body 2. The processing liquid is vigorously injected into the furnace body 2 from the injection nozzle N by pressure release and compressed air, and is gasified by a rapid pressure drop and a high-temperature space when blown out. It is discharged into the atmosphere from the opening 2c.
[0025]
Further, since the interior of the furnace body 2 is a high-temperature space A of 800 ° C. or higher, the dioxins remaining in the treatment liquid D are completely pyrolyzed in the furnace body 2. Thereby, almost 100% of the dioxins in the treatment liquid can be decomposed, detoxified, gasified, and released into the atmosphere.
[0026]
Further, as in this embodiment, when the fuel is mixed in the processing liquid, the processing liquid D injected into the furnace body 2 burns and gasifies at a higher temperature, so that the thermal decomposition of dioxins is more effectively performed. May be promoted. Since the furnace body 2 is hot, a relatively low quality fuel can be used as the fuel. For example, A heavy oil or the like is preferably used. The mixing ratio of fuel and water can be, for example, 80% water and 20% fuel by weight. Further, an oxidizing agent such as hydrogen peroxide may be added to the treatment liquid D to promote the oxidation reaction of dioxins.
[0027]
Moreover, since the furnace body 2 is provided with an air supply port O3 communicating with the fan Bb in this example, by supplying the fresh air into the furnace body 2 by driving the fan Bb, In addition to preventing overheating of the furnace body 2, combustion auxiliary air can be supplied, which is useful for burning the fuel mixed in the treatment liquid.
[0028]
Although not shown in the present example, when chlorine is contained in the gasified treatment liquid, neutralization treatment is performed as necessary. Such neutralization treatment can be performed using, for example, caustic soda or sodium carbonate.
[0029]
【The invention's effect】
As described above, in the first aspect of the present invention, the contaminants are decomposed by supercriticalizing the liquid in the treatment liquid in the heat exchange flow path, and then remain in the treatment liquid. The pollutant to be discharged is ejected into the furnace body and further thermally decomposed in the furnace body at a high temperature atmosphere of 800 ° C. or higher. For this reason, the residual amount of pollutants can be reduced, and a very high capability of decomposing pollutants can be exhibited to make them harmless. Further, since the treatment liquid is gasified by the high temperature in the furnace, it can be easily released into the atmosphere.
[0030]
Moreover, the supercriticality of the liquid can be continuously performed using the amount of heat by heat exchange with the furnace body. Further, when the fuel is mixed with the treatment liquid, the treatment liquid can be burned at a high temperature during the thermal decomposition in the furnace, and the removal of contaminants and the detoxification can be promoted more reliably.
[0031]
In the invention according to claim 3, the feeding unit can feed the processing liquid into the furnace body using an injection nozzle, and the nozzle is provided with a cooling means for cooling the nozzle. It helps to reduce the thermal fatigue of the nozzle due to high temperature processing liquid and improve the durability of the nozzle.
[0032]
According to a fourth aspect of the present invention, when the furnace body is provided with an air supply port for burning the fuel supplied to the furnace body by supplying air to the furnace body, the fuel in the treatment liquid In addition to improving combustion, it also helps to cool the inside of the road body.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a contaminant detoxification apparatus illustrating an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Pollutant detoxification device 2 Furnace body 3 Heat exchange flow path 4 Feeding part 5 Burner 6 First flow path 7 Heat exchanger 8 Second flow path N Injection nozzle

Claims (5)

Heat exchange comprising a furnace body to which a heating burner is attached and a high-temperature space of 800 ° C. or higher, and a treatment liquid containing pollutants and liquid is flowed and arranged inside the furnace body and spirally wound around the pipe body A heat exchange channel having a vessel, and a feeding unit that injects the treatment liquid that has passed through the heat exchange channel into the furnace body,
The furnace body includes a cylindrical base portion to which the heating burner is attached, and a distal end portion that is connected to one end side of the cylindrical base portion and in which the heat exchanger is disposed. ,
In the heat exchange flow path, the contaminants are decomposed by supercriticalizing the liquid in the treatment liquid, and the contaminants remaining in the treatment liquid are jetted into the furnace body, and the pyrolysis is performed in the furnace body. A pollutant detoxifying device characterized by:   The pollutant detoxifying device according to claim 1, wherein the liquid is water and the treatment liquid contains fuel.   The pollutant harmless according to claim 1 or 2, wherein the feeding section includes a nozzle capable of injecting a treatment liquid into the furnace body, and the nozzle is provided with a cooling means for cooling the nozzle. Device.   The pollutant according to any one of claims 1 to 3, wherein the furnace body is provided with an air supply port for burning fuel supplied to the furnace body by supplying air to the furnace body. Detoxification device. The pollutant detoxifying device according to any one of claims 2 to 4, wherein the fuel contained in the treatment liquid is A heavy oil.

Images