JP2009066492A - System for making contaminated soil harmless - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for making contaminated soil harmless capable of surely cleaning exhaust coming out of its dryer by removing contaminants contained in the exhaust. <P>SOLUTION: The system 1 for making contaminated soil harmless by decomposing contaminants contained in contaminated soil comprises: a dryer 21 for drying contaminated soil; a vacuum reduction-reactor/heater 24 for decomposing contaminants contained in contaminated soil dried by the dryer 21 by heating and reducing the same in vacuo; and further a vapor/gas cleaning device 37 that treats exhaust discharged from the dryer 21 upon drying contaminated soil thereby and cleans specified contaminants contained in the exhaust. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a system for detoxifying contaminated soil by decomposing contaminants by reduced pressure reduction heating.

  In recent years, soil contamination due to harmful substances has become apparent, and concerns about the impact on human health and the natural environment have expanded, and the need for technology for detoxifying contaminated soil has increased. In particular, since it is becoming difficult to secure a final disposal site for contaminated soil, an on-site contaminated soil detoxification technology that is compatible with various contaminated sites and is low-cost is required.

  In response to such demands, reduced pressure reduction thermal decomposition dechlorination treatment is known as a method for detoxifying organic chlorine-based contaminants such as dioxins and PCB (polychlorinated biphenyl). Reduced pressure reduction thermal decomposition dechlorination treatment is to detoxify by decomposing and decomposing organic chlorinated pollutants such as dioxins and PCBs in the contaminated soil by heat treating the contaminated soil in a reduced pressure atmosphere. Refers to processing. In addition, as a treatment system that shortens the treatment time and improves the treatment efficiency in the reduced pressure reduction thermal decomposition dechlorination treatment, an air dryer for drying and pulverizing the contaminated soil, And a treatment system including a reduced-pressure reduction pyrolysis dechlorination apparatus that reduces and decomposes pollutants by heating the sorted contaminated soil (see, for example, Patent Document 1). .

JP 2004-275993 A

  By the way, in the processing system by the conventional reduced pressure reduction pyrolysis dechlorination treatment, the contaminated soil is dried by introducing high-temperature drying air into the drying apparatus, and the subsequent reduced pressure reduction pyrolysis dechlorination treatment is performed. It improves efficiency and stabilizes the reaction. Therefore, when a pollutant with relatively high volatility such as PCB is contained in the contaminated soil, the pollutant is volatilized in a large amount and exhausted from the drying apparatus together with drying air and water vapor evaporated from the contaminated soil. There was a possibility. In addition, there is a possibility that dust that has risen in the state where organic pollutants such as dioxins and PCB (polychlorinated biphenyl) are adsorbed from the dried contaminated soil will be discharged from the dryer together with water vapor. It was. In these cases, in order to finally release the drying air into the atmosphere, the pollutants contained in the drying air must be detoxified, and an appropriate treatment device corresponding to the pollutants must be provided. I had to set it up. For example, when volatilized PCB is contained in the drying air, this PCB must be subjected to high temperature treatment or the like. However, since the drying air contains a large amount of water vapor evaporated from the contaminated soil, the water vapor is also introduced into the high temperature treatment together with the PCB. Therefore, the heat capacity of the processing target is increased, the energy required for the high temperature processing is very large, and the processing cost is increased.

  Correspondingly, by suppressing the volatilization of the pollutant when the contaminated soil is dried, it is possible to eliminate the combustion process of the exhaust gas from the drying device. However, even in this case, since the exhaust gas contains contaminants such as dust and odor contaminated with PCB, dioxin, etc., it cannot be discharged into the atmosphere as it is. Therefore, it has been required to remove pollutants from the exhaust gas and to purify the exhaust gas.

  The present invention has been made in view of the above, and provides a polluted soil detoxification system capable of removing pollutants contained in exhaust gas from a drying apparatus and reliably purifying the exhaust gas. For the purpose.

  In order to solve the above-described problems and achieve the object, the polluted soil detoxification system according to claim 1 is a pollution that renders the polluted soil harmless by decomposing the pollutants contained in the contaminated soil. A soil detoxification system comprising a drying device for drying the contaminated soil, a reduced pressure reduction heating device for decomposing the contaminants of the contaminated soil dried by the drying device by reduced pressure reduction heating, and the drying Exhaust gas discharged from the drying device by drying the contaminated soil in the device, exhaust gas purification means for purifying a predetermined harmful substance contained in the exhaust gas, It is provided with.

  Further, the polluted soil detoxification system according to claim 2 is the polluted soil detoxification system according to claim 1, wherein the exhaust gas purification means purifies the harmful substances by washing the exhaust gas in a liquid manner. It includes an exhaust gas cleaning device.

  Further, the polluted soil detoxification system according to claim 3 is the polluted soil detoxification system according to claim 1 or 2, wherein the exhaust gas purification means is a state in which the exhaust gas is heated to a predetermined temperature or higher. And a catalytic device for purifying the harmful substance by contacting with the catalyst.

  Moreover, the contaminated soil detoxification system according to claim 4 is the contaminated soil detoxification system according to claim 3, wherein the contaminant in the contaminated soil is decomposed by reduced pressure reduction heating by the reduced pressure reduction heating device. The exhaust gas discharged from the reduced pressure reduction heating apparatus is processed, and the exhaust gas combustion means for burning a predetermined harmful substance contained in the exhaust gas, and the exhaust gas combustion means discharged from the exhaust gas combustion means Exhaust gas from the drying device by exchanging heat between the exhaust gas after combustion and the exhaust gas discharged from the drying device or the exhaust gas from which at least a part of the harmful substances has been removed. And a heat exchange device that raises the temperature of the exhaust gas to be discharged, and the exhaust gas heated by the heat exchange device is introduced into the catalyst device.

  According to the first aspect of the present invention, since the pollutant contained in the vapor gas discharged from the drying device is removed by the exhaust gas purification means, it is not necessary to treat the vapor gas at a high temperature. Therefore, exhaust gas can be purified at low cost.

  Further, according to the invention described in claim 2, since the exhaust gas purifying means has the exhaust gas cleaning device, a small amount of dust contained in the exhaust gas, dioxin adsorbed on the dust, etc. It can be removed effectively and the exhaust gas can be purified.

  According to the invention described in claim 3, since the exhaust gas purification means has the catalyst device, the odor content and PCB etc. contained in the exhaust gas are effectively removed, and the exhaust gas is purified. can do.

  According to the invention of claim 4, by using the heat exchange device, the temperature of the exhaust gas introduced into the catalyst device is raised by the heat transferred from the exhaust gas that has passed through the exhaust gas combustion means. Therefore, the oxidation reaction of the exhaust gas in the catalyst device can be promoted efficiently. Moreover, since the temperature of the exhaust gas after combustion is lowered by passing through the heat exchange device, the load when cooling the exhaust gas can be reduced, and the energy efficiency of the contaminated soil detoxification system as a whole can be reduced. Can be improved.

  Embodiments of a contaminated soil detoxification system according to the present invention will be described below in detail with reference to the accompanying drawings. [I] First, the basic concept of the embodiment will be described, then [II] the specific contents of the embodiment will be described, and [III] Finally, modifications to the embodiment will be described. However, the present invention is not limited to the embodiments.

[I] Basic Concept of Embodiment First, a basic concept common to the embodiments will be described. The polluted soil detoxification system according to the embodiment is intended to detoxify contaminated soil containing a pollutant.

  The installation target of the contaminated soil detoxification system according to the embodiment is arbitrary. For example, it is installed at a factory site such as a chemical factory, a waste disposal site, an estuary, etc., and dioxins contained in the contaminated soil, PCBs, etc. Organochlorine pollutants can be detoxified.

  One of the features of the polluted soil detoxification system according to the embodiment is roughly as an exhaust gas purification means for removing pollutants contained in the exhaust gas discharged from the drying device and purifying the exhaust gas. The exhaust gas cleaning tank and the deodorizing catalyst layer are provided. Thereby, the contaminant contained in exhaust gas can be removed reliably. Moreover, since it is not necessary to perform high temperature treatment of exhaust gas, the operating cost of the contaminated soil detoxification system can be reduced.

[II] Specific Contents of Embodiment Next, specific contents of the embodiment according to the present invention will be described. First, the overall configuration of the contaminated soil detoxification system and the outline of the contaminated soil detoxification process by the contaminated soil detoxification system will be described. Next, details of the configuration of the exhaust gas purification means, which is a feature of the polluted soil detoxification system according to the present embodiment, will be described.

(Configuration of contaminated soil detoxification system)
FIG. 1 is a schematic view of a contaminated soil detoxification system. As shown in FIG. 1, a contaminated soil detoxification system 1 includes a contaminated soil treatment system mainly including devices indicated by white blocks, a steam gas treatment system mainly including devices indicated by hatched blocks, And, it is roughly divided into three systems of the dry distillation gas treatment system including the apparatus mainly shown by the block of the grid, and heat exchange is performed as an apparatus commonly used in a plurality of systems or all of these systems. The apparatus 50, the activated carbon adsorption tank 60, the fuel supply apparatus 70, the exhaust heat utilization piping 80, and the control panel 90 are provided.

(Configuration of contaminated soil detoxification system-contaminated soil treatment system)
The contaminated soil treatment system is a treatment system for treating the contaminated soil that has been input to the contaminated soil detoxification system 1. The soil hopper 20, the dryer 21, the blowing device 22, the conveying device 23, and the reduced pressure reduction heating device 24. And a cooling device 25.

(Configuration of contaminated soil detoxification system-soil hopper 20)
The soil hopper 20 is for supplying contaminated soil to the dryer 21. Since the specific configuration of the soil hopper 20 is known, the description thereof will be omitted. For example, the contaminated soil thrown into the soil hopper 20 by an operator is sent out at a predetermined delivery amount, and is passed through a transfer device (not shown). It is configured to supply to the dryer 21.

(Configuration of contaminated soil detoxification system-dryer 21)
The dryer 21 is for drying the contaminated soil supplied from the soil hopper 20, and corresponds to the drying device in the claims. The specific configuration of the dryer 21 is arbitrary. For example, a rotary kiln type, a belt conveyor type, or a batch type dryer can be used. In the present embodiment, a rotary kiln type dryer is taken as an example. I will give you a description. FIG. 2 is a diagram showing an outline of the configuration of the dryer 21, FIG. 2 (a) is a side view of the entire dryer 21, FIG. 2 (b) is an enlarged view of a region A in FIG. 2 (a), FIG. 2C is an enlarged view of the region B in FIG. As shown in FIG. 2, the dryer 21 includes a combustion chamber 21a, a heating unit 21b, a rotary furnace 21c, and a drive unit 21d.

  The combustion chamber 21a is for ensuring the combustion space of the heating part 21b, and is provided so that the rotary furnace 21c may be covered. Moreover, the exhaust heat utilization piping 80 is connected to the combustion chamber 21a, and the exhaust heat from the reduced pressure reduction heating device 24 is introduced into the combustion chamber 21a. Moreover, the combustion chamber 21a is provided with the exhaust outlet 21e for discharging | emitting the gas inside the combustion chamber 21a.

  The heating part 21b heats the contaminated soil in the dryer 21, and corresponds to the heat source in the claims. Specifically, fuel is combusted inside the combustion chamber 21a, and the generated soil indirectly heats the contaminated soil inside the rotary furnace 21c through the furnace wall of the rotary furnace 21c.

  The rotary furnace 21c is a substantially cylindrical furnace that dries while moving the contaminated soil charged therein, and is rotatably installed so as to penetrate the inside of the combustion chamber 21a. A contaminated soil supply port 21f is provided at one end of the rotary furnace 21c, and a contaminated soil discharge port 21g is provided at the other end. A hood 21 h is provided around the supply port 21 f and the discharge port 21 g so that dust from the contaminated soil and vapor gas evaporated and volatilized from the contaminated soil do not leak out of the dryer 21. The hood 21h on the supply port 21f side is connected to a steam gas processing system via a steam gas pipe 30 described later. Further, a steam gas temperature measuring device (not shown) is provided in the vicinity of the connection portion with the steam gas piping 30, and the steam gas discharged from the inside of the rotary furnace 21 c to the steam gas piping 30 by the steam gas temperature measuring device. The temperature is measured. The hood 21 h on the discharge port 21 g side is connected to the transport device 23.

  Further, the rotary furnace 21c is arranged so that the major axis direction thereof has an inclination of a predetermined angle from the horizontal, and the contaminated soil inside moves from the supply port 21f to the discharge port 21g by the sliding due to rotation, and is discharged. . The rotary furnace 21c is heated from the outer peripheral surface side by the combustion gas or the like supplied into the combustion chamber 21a, and the contaminated soil inside the rotary furnace 21c is transferred by heat transferred from the outer periphery to the inner periphery of the rotary furnace 21c. Is heated.

  In addition, a temperature measuring device (not shown) is installed in the vicinity of the discharge port 21g inside the rotary furnace 21c. The temperature measuring instrument measures the temperature of the contaminated soil immediately before being discharged from the discharge port 21g, and outputs the measured data to the control panel 90.

  The drive unit 21d rotates the rotary furnace 21c at a predetermined rotational speed, and is connected to the rotary furnace 21c via a chain, a gear, or the like.

(Configuration of contaminated soil detoxification system-blowing device 22)
The blowing device 22 is for blowing cooling gas into the rotary furnace 21 c in the dryer 21. The blowing device 22 includes a blower fan (not shown) and a blower pipe (not shown). The blower fan blows the cooling gas. One end of the blowing pipe is connected to the blower fan, and the other end is connected to the rotary furnace 21 c of the dryer 21. As a result, the cooling gas blown from the blower fan passes through the blowing pipe and is blown toward the inside of the rotary furnace 21c to directly cool the contaminated soil. In addition, although the gas used as the cooling gas is arbitrary, for example, the outside air can be blown from the blower fan as the cooling gas.

(Configuration of contaminated soil detoxification system-transport device 23)
The conveyance device 23 is for conveying the contaminated soil discharged from the dryer 21 to the reduced pressure reduction heating device 24. Although the specific structure of the conveying apparatus 23 is arbitrary, for example, by using a hermetic belt conveyor or the like, the conveying device 23 can be conveyed without scattering contaminated soil to the outside.

(Configuration of contaminated soil detoxification system-reduced pressure reduction heating device 24)
The reduced pressure reduction heating device 24 is for detoxifying the contaminated soil dried by the dryer 21. As the reduced pressure reduction heating device 24, a rotary kiln heating furnace can be used. FIG. 3 is a diagram showing an outline of the configuration of the reduced pressure reduction heating device 24, FIG. 3 (a) is a side view of the whole reduced pressure reduction device (partially cut away), and FIG. 3 (b) is a diagram. 3 (a) is an enlarged view of region C, and FIG. 3 (c) is an enlarged view of region D in FIG. 3 (a). FIG. 4 is a side view showing the internal structure of the rotary furnace 24c. As shown in FIG. 3, the reduced pressure reduction heating device 24 includes a combustion chamber 24a, a heating unit 24b, a rotary furnace 24c, and a drive unit 24d.

  The combustion chamber 24a is for ensuring the combustion space of the heating unit 24b, and is provided so as to cover the rotary furnace 24c. The combustion chamber 24a includes an exhaust outlet 24e for discharging the gas inside the combustion chamber 24a to the outside. An exhaust heat utilization pipe 80 (not shown in FIG. 3) is connected to the exhaust outlet 24e, and the combustion gas after heating the rotary furnace 24c passes through the exhaust heat utilization pipe 80 from the exhaust outlet 24e. And supplied to the dryer 21.

  The heating unit 24 b heats the contaminated soil in the reduced pressure reduction heating device 24. Specifically, fuel such as LPG is combusted inside the combustion chamber 24a, and the generated soil indirectly heats the contaminated soil inside the rotary furnace 24c through the furnace wall of the rotary furnace 24c.

  The rotary furnace 24c is a substantially cylindrical furnace that heats while moving the contaminated soil thrown into the rotary furnace 24c, and is rotatable substantially horizontally so as to penetrate the inside of the combustion chamber 24a. Is installed. The rotary furnace 24c is provided with a contaminated soil supply port 24f at one end and a contaminated soil discharge port 24g at the other end, and around the supply port 24f and the discharge port 24g, dust or A hood 24h for preventing leakage of dry distillation gas is provided. The hood 24h on the supply port 24f side is connected to a dry distillation gas processing system via a later-described dry distillation gas pipe 40, and the hood 24h on the discharge port 24g side is connected to the cooling device 25.

  Further, as shown in FIG. 4, a spiral feed blade 24i is provided on the inner peripheral surface of the rotary furnace 24c, and the contaminated soil inside the rotary furnace 24c is fed with the rotation of the rotary furnace 24c. 24i moves from one end of the rotary furnace 24c to the other end and is discharged. A temperature measuring device 24j for measuring the temperature of contaminated soil is installed inside the rotary furnace 24c.

  The drive unit 24d rotates the rotary furnace 24c at a predetermined rotational speed, and is connected to the rotary furnace 24c via a chain, a gear, or the like.

  Here, since the gas inside the rotary furnace 24c is sucked into the dry distillation gas processing system, a reduced-pressure reducing atmosphere is maintained inside the rotary furnace 24c. Further, the rotary furnace 24c is heated from the outer peripheral surface side by the combustion gas supplied into the combustion chamber 24a, and contamination inside the rotary furnace 24c is caused by heat transferred from the outer periphery to the inner periphery of the rotary furnace 24c. The soil is heated. In this way, the contaminated soil is rendered harmless by being heated and maintained in a predetermined temperature range in the reduced-pressure reducing atmosphere.

(Configuration of contaminated soil detoxification system-cooling device 25)
In FIG. 1, a cooling device 25 cools contaminated soil that has been rendered harmless by the reduced pressure reduction heating device 24. When dioxins are contained in the contaminated soil, even if once detoxified by being heated to a predetermined temperature in the reduced pressure reduction heating device 24 and then detoxified, it is left for a long time in a certain temperature range when the temperature drops thereafter. As a result, dioxins may be re-synthesized by using the metal in the contaminated soil as a catalyst. Therefore, the recombined dioxins can be prevented by rapidly cooling the detoxified contaminated soil by the cooling device 25. FIG. 5 is a side view of the cooling device 25 (partially cut away). As shown in FIG. 5, the cooling device 25 includes a rotating body 25a, a drive unit 25b, a water supply pipe 25c, and a water spray device 25d.

  The rotary body 25a is a substantially cylindrical rotary body that cools while moving the detoxified contaminated soil that has been put into the rotary body 25a. The rotary body 25a is rotatably installed so that the major axis direction is substantially horizontal. Yes. The rotating body 25a is provided with a contaminated soil supply port 25e at one end and a contaminated soil discharge port 25f at the other end. Further, a spiral feed blade 25g is provided inside the rotating body 25a, and the contaminated soil inside can be moved by rotating the rotating body 25a. Further, a temperature measuring device (not shown) is installed inside the rotating body 25a. The temperature measuring instrument measures the temperature of the contaminated soil at a predetermined position inside the rotator 25 a and outputs the measured data to the control panel 90.

  The drive unit 25b rotates the rotating body 25a at a predetermined rotation speed, and is connected to the rotating body 25a via a gear or the like.

  The water supply pipe 25c is for indirectly cooling the contaminated soil inside through the wall surface of the rotating body 25a by flowing cooling water on the outer peripheral surface of the rotating body 25a. Specifically, a water supply pipe 25c is disposed along the long axis direction of the rotating body 25a, and water discharge heads 25h are provided at predetermined intervals in the water supply pipe 25c. The water discharge direction of the water discharge head 25h is directed to the rotating body 25a. When the cooling water is supplied to the water supply pipe 25c, the cooling water is discharged from the water discharge head 25h to the outer peripheral surface of the rotating body 25a, and the internal contaminated soil is indirectly cooled through the wall surface of the cooled rotating body 25a.

  The water spraying device 25d is for spraying the cooling water directly on the contaminated soil inside the rotating body 25a when the cooling capacity is lowered. Specifically, outside the cooling device 25, one end of the water spray device 25d and the water supply pipe 25c are connected via a valve (not shown). The other end of the water spray device 25d is disposed inside the rotating body 25a, and a spray port 25i for spraying water is provided at the end. When the valve is operated by a predetermined operation means and the cooling water is supplied to the water spraying device 25d, the cooling water is sprayed from the spray port 25i to the contaminated soil inside the rotating body 25a, and the contaminated soil is directly cooled. The

(Configuration of contaminated soil detoxification system-steam gas treatment system)
The steam gas processing system is a processing system for processing steam gas including moisture evaporated from the contaminated soil dried in the dryer 21 and contaminated dust to which contaminants are attached. A pipe 31, a dust collector 32, an activated carbon supply device 33, a heat retaining gas pipe 34, a dust collection dust pipe 35, a dust collection dust recovery machine 36, and a steam gas purification device 37 are provided. FIG. 6 is a schematic view schematically showing the apparatus configuration of the steam gas processing system. Here, “steam gas” in the description of the present embodiment refers to steam evaporated from the contaminated soil dried in the dryer 21, gas such as PCB or odor that has volatilized from the contaminated soil, and scattered from the contaminated soil. This refers to a gaseous substance that contains dust, dioxin, etc. adhering to the dust, or a part of these substances removed and decomposed.

(Configuration of contaminated soil detoxification system-steam gas piping 30)
The steam gas pipe 30 is for introducing the steam gas into a device belonging to the above-described steam gas processing system in a predetermined order, and connects devices that perform continuous processing before and after.

(Configuration of contaminated soil detoxification system-emergency piping 31)
The emergency pipe 31 is an emergency when the temperature of the soil heated in the dryer 21 exceeds a predetermined temperature range, or when the steam gas discharged from the dryer 21 to the steam gas pipe 30 falls below a predetermined temperature. At this time, the vapor gas is not introduced into the dust collector 32 but is introduced into a high-temperature dust collector 41 described later in the dry distillation gas treatment system. Specifically, one end of the emergency pipe 31 is connected to the steam gas pipe 30 via the switching damper 39 between the dryer 21 and the dust collector 32. The other end of the emergency pipe 31 is connected to a later-described dry distillation gas pipe 40 in the dry distillation gas processing system. The switching damper 39 is controlled by the control panel 90 based on the temperature signal output from the steam gas temperature measuring device in the dryer 21.

(Constitution of contaminated soil detoxification system-dust collector 32)
The dust collector 32 is for collecting dust contained in the vapor gas. The dust collector 32 is connected to the dryer 21 via the steam gas pipe 30, and the steam gas generated inside the dryer 21 is introduced into the dust collector 32. In addition, the dust collector 32 is connected to the dust collector 36 through the dust collector pipe 35, and the dust collected by the dust collector 32 passes through the dust collector pipe 35. It is conveyed to. Although the specific configuration of the dust collector 32 is arbitrary, for example, a cyclone dust collector 32a or a bag filter dust collector 32b can be used, or these dust collectors can be used in combination. In the present embodiment, as shown in FIG. 5, an example is shown in which one cyclone dust collector 32a and two bag filter dust collectors 32b are used. Further, a heat insulation jacket 32c is provided so as to cover the periphery of the dust collector 32, and the temperature of the dust collector 32 can be maintained within a predetermined temperature range by blowing a heat insulation gas into the heat insulation jacket 32c. .

(Configuration of contaminated soil detoxification system-activated carbon supply device 33)
The activated carbon supply device 33 is for blowing a predetermined amount of activated carbon into the dust collector 32, and is connected to the steam gas pipe 30 on the entrance side of the dust collector 32. The dust collection rate can be increased by adsorbing the dust contained in the vapor gas to the activated carbon and collecting the activated carbon on which the dust is adsorbed by the dust collector 32. The collected activated carbon is conveyed together with the dust collected by the dust collector 32 through the dust collection dust pipe 35.

(Configuration of contaminated soil detoxification system-insulated gas piping 34)
The heat insulating gas pipe 34 is for supplying a heat insulating gas into the heat insulating jacket 32c covering the periphery of the dust collector 32 so as to keep the dust collector 32 at a predetermined temperature or higher and to convection around the dust collector 32. .

(Constitution of contaminated soil detoxification system-dust collection dust pipe 35)
The dust collection pipe 35 is for conveying the dust collected by the dust collector 32 to the dust collection machine 36. The specific configuration of the dust collection dust pipe 35 is arbitrary. For example, one end of the dust collection dust pipe 35 is connected to a conveyance air supply unit 35a that supplies dust conveyance air, and the other The end may be connected to the dust collecting dust collecting machine 36. In this case, in order to prevent the dust collection dust pipe 35 from being blocked due to a decrease in the air temperature, the hot air discharged from the dryer 21 after being used for heating the dryer 21 may be used as the conveying air. . Alternatively, the collected dust can be transferred to the dust collection machine 36 by a belt conveyor.

(Configuration of contaminated soil detoxification system-dust collection machine 36)
The dust collection dust collector 36 is for collecting the dust conveyed by the dust collection dust pipe 35, and for example, a bag filter type dust collector is used. The dust collected by the dust collection dust collector 36 is put into the reduced pressure reduction heating device 24 together with the contaminated soil dried by the dryer 21.

(Configuration of contaminated soil detoxification system-steam gas purification device 37)
The steam gas purification device 37 is for removing dust, dioxin and the like contained in a trace amount in the steam gas that has passed through the dust collector 32, and corresponds to the exhaust gas purification means in the claims. Details of the configuration of the steam gas purification device 37 will be described later.

(Configuration of contaminated soil detoxification system-dry distillation gas treatment system)
In FIG. 1, a dry distillation gas treatment system is a treatment system for treating dry distillation gas containing organic chlorine-based contaminants such as dioxins and PCBs separated from contaminated soil in the course of reduced pressure reduction heat treatment. A gas pipe 40, a high-temperature dust collector 41, a slaked lime supply device 42, a granulator 43, a bypass pipe 44, an exhaust gas oxidation device 45, an exhaust gas cooling device 46, a dust collector 47, and a desulfurization device 48 are provided. FIG. 7 is a schematic view schematically showing the apparatus configuration of the dry distillation gas treatment system.

(Configuration of contaminated soil detoxification system-dry distillation gas piping 40)
The dry distillation gas pipe 40 is for introducing the dry distillation gas into the devices belonging to the above-described dry distillation gas processing system in a predetermined order, and connects the devices that perform continuous processing before and after. Further, one end of the emergency pipe 31 in the steam gas processing system is connected to the dry distillation gas pipe 40 between the vacuum reduction heating device 24 and the high temperature dust collector 41 in FIG. To be introduced.

(Configuration of contaminated soil detoxification system-high temperature dust collector 41)
The high-temperature dust collector 41 is for collecting dust contained in the high-temperature dry distillation gas. The high-temperature dust collector 41 is connected to the rotary furnace 24 c of the reduced pressure reduction heating device 24 through the dry distillation gas pipe 40 and is connected to the dry distillation gas pipe 40. Is connected to the exhaust gas oxidation device 45. The dry distillation gas separated from the contaminated soil inside the rotary furnace 24c is introduced into the high-temperature dust collector 41 via the dry distillation gas pipe 40, and after dust contained in the dry distillation gas is removed, the dry distillation gas is supplied to the exhaust gas oxidation device 45. And discharged. The dust collected by the high temperature dust collector 41 is transferred to the granulator 43. Dust is collected by the high-temperature dust collector 41 and the inflow of dust into the exhaust gas oxidizer 45 is prevented, so that generation of soot inside the exhaust gas oxidizer 45 can be prevented, and the exhaust gas oxidizer 45 is stopped for maintenance. The need to do so can be reduced. In addition, although the specific structure of the high temperature dust collector 41 is arbitrary, the high temperature dust collector 41 which improved the heat resistance performance using the ceramic filter can be used, for example.

(Configuration of contaminated soil detoxification system-slaked lime supply device 42)
In FIG. 7, a slaked lime supply device 42 is for injecting slaked lime into the dry distillation gas in order to neutralize the acidic gas contained in the dry distillation gas. In this Embodiment, in order to protect the apparatus which belongs to a dry distillation gas system | strain from corrosion by acidic gas, before introducing into the high temperature dust collector 41, slaked lime is injected | thrown-in. That is, the slaked lime supply device 42 is connected to the dry distillation gas pipe 40 on the reduced pressure reduction heating device 24 side of the high temperature dust collector 41. However, the connection position of the slaked lime supply device 42 is arbitrary, and is connected to the dry distillation gas pipe 40 between the exhaust gas cooling device 46 and the dust collector 47, for example, at a later stage than the high temperature dust collector 41, and flows through the dry distillation gas pipe 40. It is also possible to put slaked lime into the dry distillation gas.

(Configuration of contaminated soil detoxification system-granulator 43)
The granulator 43 is for forming the dust collected by the high-temperature dust collector 41 as granules having a predetermined size. The dust collected by the high temperature dust collector 41 is measured by a dust meter (not shown) and then introduced into a kneader (not shown). Here, in accordance with the amount of dust previously measured, a binder is supplied from a silo (not shown) to the kneader and water is supplied from a water supply (not shown). The dust kneaded with the binder and water by the kneader is formed into granules by the granulator 43. Thus, dust can be made into granules by the granulator 43, and the granules can be prevented from flowing into the dry distillation gas treatment apparatus again by being put into the reduced pressure reduction heating device 24. In addition, since the specific structure of the granulator 43 is well-known, description is abbreviate | omitted.

(Configuration of contaminated soil detoxification system-bypass piping 44)
The bypass pipe 44 does not allow the dry distillation gas to be introduced into the high temperature dust collector 41 when the temperature of the dry distillation gas before introduction into the high temperature dust collector 41 is equal to or lower than a predetermined temperature. 45 is introduced. Specifically, one end of the bypass pipe 44 and the dry distillation gas pipe 40 are connected via the switching damper 49 on the reduced pressure reduction heating apparatus 24 side of the connection part between the slaked lime supply device 42 and the dry distillation gas pipe 40. Has been. The other end of the bypass pipe 44 is connected to the exhaust gas oxidation device 45 through the dry distillation gas pipe 40. Further, a temperature measuring device (not shown) for measuring the temperature of the dry distillation gas is provided in the vicinity of the switching damper 49. The switching operation of the switching damper 49 is controlled by the control panel 90 based on the temperature signal output from the temperature measuring instrument.

(Configuration of contaminated soil detoxification system-exhaust gas oxidation device 45)
The exhaust gas oxidizer 45 is for subjecting organic chlorine-based pollutants such as dioxins and PCBs contained in the dry distillation gas that has passed through the high-temperature dust collector 41 to high-temperature incineration. It corresponds. The exhaust gas oxidation device 45 includes an inflow part, an incineration part, and an outflow part (not shown). The inflow portion is a portion into which dry distillation gas flows, and is connected to the high-temperature dust collector 41 and the bypass pipe 44 through the dry distillation gas pipe 40. An incinerator is a part which incinerates the dry distillation gas which flowed in from the inflow part. Fuel such as LPG and auxiliary combustion air are supplied to the incinerator to incinerate dry distillation gas. The outflow part is a part through which the dry distillation gas incinerated in the incineration part flows out, and is connected to the heat exchanger 50 via the dry distillation gas pipe 40.

(Configuration of contaminated soil detoxification system-exhaust gas cooling device 46)
The exhaust gas cooling device 46 is for cooling the dry distillation gas that has passed through the heat exchanger 50. The inflow side of the dry distillation gas in the exhaust gas cooling device 46 is connected to the heat exchanger 50 through the dry distillation gas pipe 40, and the outflow side is connected to the dust collector 47 through the dry distillation gas pipe 40. The specific configuration of the exhaust gas cooling device 46 is arbitrary, and a water-cooled gas cooling device or an air-cooled gas cooling device can be used.

(Constitution of contaminated soil detoxification system-dust collector 47)
The dust collector 47 is for collecting dust remaining in a trace amount in the dry distillation gas that has passed through the exhaust gas cooling device 46. The inflow side of the dry distillation gas in the dust collector 47 is connected to the exhaust gas cooling device 46 through the dry distillation gas piping 40, and the outflow side is connected to the desulfurization device 48 through the dry distillation gas piping 40. In addition, although the specific structure of the dust collector 47 is arbitrary, the cyclone type dust collector 47a and the bag filter type dust collector 47b can be used.

(Configuration of contaminated soil detoxification system-desulfurization device 48)
The desulfurization device 48 is for removing sulfur oxides and nitrogen oxides contained in the dry distillation gas that has passed through the dust collector 47. The inflow side of the dry distillation gas in the desulfurization device 48 is connected to the dust collector 47 through the dry distillation gas pipe 40, and the outflow side is connected to the activated carbon adsorption tank 60 through the dry distillation gas pipe 40. Although the specific structure of the desulfurization apparatus 48 is arbitrary, the wet desulfurization apparatus which uses an alkaline slurry and an alkaline solution as an absorber can be used, for example.

(Configuration of contaminated soil detoxification system-heat exchanger 50)
The heat exchanger 50 is for causing heat exchange between the dry distillation gas that has passed through the exhaust gas oxidizer 45 in the dry distillation gas treatment system and the vapor gas in the steam gas treatment system. Compatible with heat exchange devices. Details of the configuration of the heat exchanger 50 will be described later.

(Configuration of contaminated soil detoxification system-activated carbon adsorption tank 60)
In FIG. 1, the activated carbon adsorption tank 60 has a small amount of dust, odor, etc. remaining in the vapor gas that has passed through the vapor gas purification device 37 in the vapor gas treatment system and the dry distillation gas that has passed through the desulfurization device 48 in the dry distillation gas treatment system. If this is the case, it is for adsorbing it. When exhaust gas passes through the inside of the activated carbon adsorption tank 60, dust, odor, etc. contained in the exhaust gas are adsorbed and removed by the activated carbon. The inflow side of the activated carbon adsorption tank 60 is connected to a steam gas purification device 37 and a desulfurization device 48 via a pipe (not shown), and the outflow side is connected to a chimney 100 for exhausting exhaust gas into the atmosphere. . In addition, since the specific structure of the activated carbon adsorption tank 60 is well-known, description is abbreviate | omitted.

(Configuration of contaminated soil detoxification system-fuel supply device 70)
The fuel supply device 70 is for supplying fuel and auxiliary combustion air to the dryer 21, the reduced pressure reduction heating device 24, and the exhaust gas oxidation device 45.

(Configuration of contaminated soil detoxification system-Waste heat utilization piping 80)
The exhaust heat utilization pipe 80 is for allowing the exhaust heat of the reduced pressure reduction heating device 24 to be utilized in the dryer 21. Specifically, one end of the exhaust heat utilization pipe 80 is connected to an exhaust fan provided in the combustion chamber 24 a of the reduced pressure reduction heating device 24, and the other end is connected to the combustion chamber 21 a of the dryer 21. ing. In the combustion chamber 24a of the reduced-pressure reduction heating device 24, the combustion gas generated by burning the fuel by the heating unit 24b heats the rotary furnace 24c, and then passes through the exhaust heat utilization piping 80 to the dryer 21. It is introduced into the combustion chamber 21a.

(Configuration of contaminated soil detoxification system-control panel 90)
The control panel 90 is for controlling the operation of the contaminated soil detoxification system 1. FIG. 8 is a block diagram functionally conceptually showing the electrical configuration of the control panel 90. As shown in FIG. 8, the control panel 90 includes a dryer control unit 91, a reduced pressure reduction heating device control unit 92, a cooling device control unit 93, a steam gas processing control unit 94, a dry distillation gas processing control unit 95, an input unit 96, In addition, a storage unit 97 is provided. The dryer control unit 91 controls the dryer 21 and the blowing device 22 and corresponds to the temperature control means in the claims. The reduced pressure reduction heating device control unit 92 controls the reduced pressure reduction heating device 24. The cooling device control unit 93 controls the cooling device 25. The steam gas processing control unit 94 performs switching control of the switching damper 39 for the emergency pipe 31 of the steam gas processing system. The dry distillation gas processing control unit 95 performs switching control of the switching damper 49 for the bypass piping 44 of the dry distillation gas processing system. The input unit 96 is for causing the control panel 90 to input operation information used for control by the control panel 90, such as properties such as moisture content of the contaminated soil and the input amount. The storage unit 97 stores operation information input to the control panel 90 via the input unit 96.

  Although the specific configuration of the control panel 90 is arbitrary, for example, a control program such as an OS (Operating System), a program defining various processing procedures, an internal memory for storing necessary data, and these And a CPU (Central Processing Unit) for executing the program.

(Processing flow by the pollution soil detoxification system)
Next, an outline of the contaminated soil detoxification process performed by the contaminated soil detoxification system 1 will be described. FIG. 9 is a flowchart showing the flow of the contaminated soil detoxification process.

(Flow of treatment by contaminated soil detoxification system-contaminated soil)
First, the processing flow of contaminated soil will be described. At the start of the treatment, the contaminated soil that has undergone a predetermined pre-stage treatment such as classification and measurement of the contaminated soil is put into the soil hopper 20. The contaminated soil thrown into the soil hopper 20 is first sent out from the soil hopper 20 in a predetermined delivery amount and transferred to the dryer 21 by the transfer device (step SA-1). The dryer 21 is controlled by the dryer controller 91, and the temperature of the contaminated soil charged into the dryer 21 and the temperature of the vapor gas discharged from the dryer 21 are maintained within a predetermined temperature range. The contaminated soil is dried (step SA-2). The contaminated soil that has moved through the rotary furnace 21c to the discharge port 21g is discharged from the discharge port 21g (step SA-3).

  The contaminated soil discharged from the dryer 21 is transported to the reduced pressure reduction heating device 24 by the transport device 23 (step SA-4). The contaminated soil transported to the reduced pressure reduction heating device 24 is introduced into the rotary furnace 24c from the supply port 24f (step SA-5). The contaminated soil charged into the rotary furnace 24c is heated from the combustion gas or the like in the combustion chamber 24a through the furnace wall of the rotary furnace 24c (step SA-6). At this time, the reduced pressure reduction heating device control unit 92 controls the heating amount of the rotary furnace 24c by the heating unit 24b based on the temperature of the contaminated soil measured by the temperature measuring device 24j. Specifically, the temperature of the contaminated soil measured by the temperature measuring devices 24j provided at a plurality of points inside the rotary furnace 24c is maintained at 574 ° C. or higher, preferably 667 ° C. or higher for 10 minutes or longer. The heating unit 24b is controlled. Under these conditions, organic chlorine-based contaminants such as dioxins and PCBs contained in the contaminated soil are separated from the contaminated soil and decomposed by reduced-pressure reduction heating. At this time, the dry distillation gas containing organic chlorinated contaminants such as dioxins and PCB separated from the contaminated soil is discharged to the dry distillation gas pipe 40 from the hood 24h on the supply port 24f side of the rotary furnace 24c. The contaminated soil that has moved through the rotary furnace 24c to the discharge port 24g is discharged from the discharge port 24g (step SA-7).

  The contaminated soil discharged from the rotary furnace 24c of the reduced pressure reduction heating device 24 is put into the rotary body 25a of the cooling device 25 (step SA-8). The contaminated soil introduced into the rotator 25a from the supply port 25e of the rotator 25a is indirectly cooled through the wall surface of the rotator 25a by the cooling water discharged to the outer peripheral surface of the rotator 25a ( Step SA-9). When the cooling device control unit 93 determines that the cooling capacity of the cooling device 25 is reduced based on the temperature rise of the contaminated soil inside the rotating body 25a (step SA-10, Yes), the water The spraying device 25d sprays the cooling water on the contaminated soil and directly cools the contaminated soil (step SA-11). The contaminated soil that has moved inside the rotating body 25a to the discharge port 25f is discharged from the discharge port 25f (step SA-12). The discharged contaminated soil is carried out by a predetermined carrying-out means as detoxified soil.

(Treatment flow by contaminated soil detoxification system-steam gas)
Next, the process flow of the vapor gas evaporated from the contaminated soil when the contaminated soil is dried in the dryer 21 will be described. FIG. 10 is a flowchart showing the flow of the steam gas processing. The vapor gas evaporated from the contaminated soil in Step SA-2 described above includes moisture contained in the contaminated soil, dust scattered from the contaminated soil, odors volatilized from the contaminated soil, and the like. This steam gas is discharged from the dryer 21 to the steam gas pipe 30 (step SB-1). Here, when the steam gas temperature measured by the steam gas temperature measuring device is less than a predetermined temperature (for example, about 70 ° C.) (step SB-2, Yes), the steam gas processing control unit 94 operates the switching damper 39. The steam gas is introduced into the dry distillation gas processing system via the emergency pipe 31 (step SB-3). When the vapor gas temperature is equal to or higher than the predetermined temperature (step SB-2, No), the vapor gas introduced into the vapor gas pipe 30 is introduced into the dust collector 32 (step SB-4). Here, activated carbon is blown into the dust collector 32 by the activated carbon supply device 33, and dust contained in the vapor gas is adsorbed to the activated carbon. When the steam gas introduced into the dust collector 32 passes through a cyclone, a bag filter, or the like, dust contained in the steam gas or activated carbon adsorbed by the dust is removed (step SB-5). The dust and the like removed here are conveyed to the dust collecting dust collecting machine 36 via the dust collecting dust pipe 35 and are put into the reduced pressure reduction heating device 24 from the dust collecting dust collecting machine 36.

The vapor gas that has passed through the dust collector 32 is introduced into the vapor gas purification device 37 (step SB-6). In the steam gas purification device 37, the contaminant contained in the steam gas is removed (step SB-7). Details of the purification process of the vapor gas in the vapor gas purification device 37 will be described later.

  The vapor gas that has passed through the vapor gas purification device 37 is introduced into the activated carbon adsorption tank 60 (step SB-8). When the vapor gas is introduced into the activated carbon adsorption tank 60, dust, odors and the like remaining in a minute amount in the vapor gas are adsorbed and removed by the activated carbon (step SB-9). The vapor gas that has passed through the activated carbon adsorption tank 60 is introduced into the chimney 100 and released from the chimney 100 to the atmosphere (step SB-10).

(Treatment flow by decontaminated soil system-dry distillation gas)
Next, the process flow of the dry distillation gas separated from the contaminated soil during the reduced pressure reduction heat treatment of the contaminated soil in the reduced pressure reduction heating device 24 will be described. FIG. 11 is a flowchart showing a process flow of the dry distillation gas. The dry distillation gas separated from the contaminated soil in step SA-6 is discharged to the dry distillation gas pipe 40 from the hood 24h on the supply port 24f side of the rotary furnace 24c (step SC-1). Here, when the temperature of the dry distillation gas measured by the temperature measuring instrument arranged in the vicinity of the switching damper 49 of the dry distillation gas pipe 40 is lower than the predetermined temperature (step SC-2, Yes), the dry distillation gas processing control. The unit 95 operates the switching damper 49 to introduce the dry distillation gas into the exhaust gas oxidizer 45 through the bypass pipe 44 (step SC-3). When the temperature of the dry distillation gas is equal to or higher than the predetermined temperature (step SC-2, No), the dry distillation gas introduced into the dry distillation gas pipe 40 is introduced into the high temperature dust collector 41 (step SC-4). When the dry distillation gas passes through the high temperature dust collector 41, the dust contained in the dry distillation gas is collected by the filter of the high temperature dust collector 41 (step SC-5). Note that the dust collected by the high-temperature dust collector 41 is transferred to the granulator 43, granulated by the granulator 43, and then charged into the reduced pressure reduction heating device 24.

  The dry distillation gas that has passed through the high temperature dust collector 41 is introduced into the exhaust gas oxidation device 45 (step SC-6). The dry distillation gas that has flowed into the incineration unit from the inflow unit of the exhaust gas oxidizer 45 is incinerated with the fuel and auxiliary combustion air supplied to the incineration unit (step SC-7). As a result, organic chlorine-based pollutants such as dioxins and PCBs contained in the dry distillation gas are oxidized and rendered harmless. The incinerated dry distillation gas is discharged from the outflow part.

  The dry distillation gas discharged from the exhaust gas oxidation device 45 is introduced into the heat exchanger 50. In the heat exchanger 50, the dry distillation gas releases heat to the vapor gas through the heat exchanger 50 (step SC-8).

  The dry distillation gas whose temperature has dropped in the heat exchanger is introduced into the exhaust gas cooling device 46 (step SC-9). When the dry distillation gas is introduced into the exhaust gas cooling device 46, the dry distillation gas is cooled to a predetermined temperature range (step SC-10).

  The dry distillation gas cooled by the exhaust gas cooling device 46 is introduced into the dust collector 47 (step SC-11). In the dust collector 47, a small amount of dust remaining in the dry distillation gas is collected (step SC-12).

  The dry distillation gas that has passed through the dust collector 47 is introduced into the desulfurization device 48 (step SC-13). When dry distillation gas is introduced into the desulfurization device 48, sulfur oxides and nitrogen oxides contained in the dry distillation gas are removed (step SC-14).

  The dry distillation gas that has passed through the desulfurization device 48 is introduced into the activated carbon adsorption tank 60 (step SC-15). When the dry distillation gas is introduced into the activated carbon adsorption tank 60, dust, odors, and the like remaining in a trace amount in the dry distillation gas are adsorbed and removed by the activated carbon (step SC-16). The vapor gas that has passed through the activated carbon adsorption tank 60 is introduced into the chimney 100 and released from the chimney 100 to the atmosphere (step SC-17).

(Configuration of the steam gas purification device 37)
Next, the configuration of the steam gas purification device 37 will be described. As shown in FIG. 6, the steam gas purification device 37 includes a steam gas cleaning tank 37a and a deodorization catalyst device 37b.

(Configuration of Steam Gas Purifying Device 37-Steam Gas Cleaning Tank 37a)
The steam gas cleaning tank 37a is for removing dust contained in a trace amount in the steam gas that has passed through the dust collector 32, and corresponds to the exhaust gas cleaning device in the claims.

  The specific configuration of the steam gas cleaning tank 37a is arbitrary, and for example, a wet scrubber which is a kind of wet dust collector can be used. The wet scrubber includes a cleaning liquid tank (not shown) for storing a cleaning liquid. Vapor gas is sprayed at a high speed onto the liquid level of the cleaning liquid stored in the cleaning liquid tank, and fine droplets of the cleaning liquid scattered from the liquid level are mixed with the vapor gas. Thus, by bringing the atomized cleaning liquid into contact with the vapor gas, the dust can be adsorbed to the cleaning liquid and collected.

  As described above, the vapor gas contains dust scattered from the contaminated soil, and most of the dioxins and the like contained in the vapor gas are attached to the dust. Therefore, dioxins and the like contained in the steam gas can be removed by removing dust from the steam gas.

(Configuration of contaminated soil detoxification system-deodorization catalyst device 37b)
The deodorization catalyst device 37b is for removing a trace amount of odor, PCB, and the like contained in the steam gas that has passed through the steam gas cleaning tank 37a, and corresponds to the catalyst device in the claims.

  The deodorization catalyst device 37b includes a catalyst (not shown) for promoting the oxidation reaction of the vapor gas. By bringing the vapor gas heated to a predetermined temperature (for example, about 350 ° C.) or more into contact with the catalyst, the odor or PCB contained in the vapor gas is oxidized / decomposed and rendered harmless. Although the specific configuration of the deodorization catalyst device 37b is arbitrary, a catalyst having a surface area increased in various shapes such as pellets, honeycombs, metal foams, etc., using noble metals such as platinum and palladium as active components. be able to.

(Configuration of heat exchanger 50)
Next, the configuration of the heat exchanger 50 will be described. The heat exchanger 50 is for causing heat exchange between the steam gas that has passed through the steam gas cleaning tank 37a in the steam gas processing system and the dry distillation gas that has passed through the exhaust gas oxidizer 45 in the dry distillation gas processing system. It is. The specific configuration of the heat exchanger 50 is arbitrary, and for example, a radiant heat exchanger having a double cylinder of an inner cylinder and an outer cylinder can be used.

  The steam gas is heated to a temperature (for example, 350 ° C.) required for the catalytic reaction in the deodorizing catalyst device 37b at the subsequent stage by receiving heat from the dry distillation gas in the heat exchanger 50. Further, since the dry distillation gas is deprived of heat by the steam gas in the heat exchanger 50, the efficiency of the exhaust gas cooling device 46 in the subsequent stage is improved.

(Steam gas purification process in the steam gas purification device 37)
Next, the steam gas purification process in the steam gas purification device 37 will be described. FIG. 12 is a flowchart showing the flow of the steam gas purification process in the steam gas purification device 37. In the above step SB-6, when the vapor gas is introduced from the dust collector 32 into the vapor gas purification device 37, the vapor gas is first introduced into the vapor gas cleaning tank 37a (step SD-1). In the steam gas cleaning tank 37a, a very small amount of dust, dioxin and the like contained in the steam gas are removed (step SD-2).

  After passing through the steam gas cleaning tank 37a, the steam gas is introduced into the heat exchanger 50. In the heat exchanger 50, the steam gas receives heat from the dry distillation gas via the heat exchanger 50. As a result, the vapor gas is heated to a temperature required for the reaction in the subsequent deodorization catalyst device 37b (step SD-3).

  The steam gas whose temperature has been raised in the heat exchanger 50 is introduced into the deodorization catalyst device 37b (step SD-4). When the vapor gas is introduced into the deodorization catalyst device 37b, the catalyst of the deodorization catalyst device 37b promotes oxidation reaction of odor components and PCBs contained in a small amount in the vapor gas and renders the vapor gas harmless (step) SD-5).

(Effect of embodiment)
As described above, according to the present embodiment, the contaminant contained in the steam gas discharged from the dryer 21 is removed by the steam gas purification device 37, so that it is not necessary to subject the steam gas to a high temperature treatment. Therefore, the vapor gas can be purified at a low cost.

  Further, since the steam gas purification device 37 has a steam gas cleaning tank 37a, it effectively removes a small amount of dust contained in the steam gas, dioxins adsorbed to the dust, etc. Can be purified.

  In addition, since the steam gas purification device 37 has the deodorization catalyst device 37b, it is possible to effectively remove odor components, PCB, and the like contained in the steam gas and purify the steam gas.

  Further, by using the heat exchanger 50, the temperature of the vapor gas introduced into the deodorization catalyst device 37b can be raised by the heat transferred from the dry distillation gas that has passed through the exhaust gas oxidation device 45, so the deodorization catalyst device 37b. The oxidation reaction in can be efficiently promoted. Further, since the temperature of the dry distillation gas is lowered by passing through the heat exchanger 50, the load of the exhaust gas cooling device 46 can be reduced, and the energy efficiency of the contaminated soil detoxification system 1 can be improved. .

[III] Modifications to Embodiments While the embodiments according to the present invention have been described above, the specific configuration and means of the present invention are within the scope of the technical idea of each invention described in the claims. Can be arbitrarily modified and improved. Hereinafter, such a modification will be described.

(About problems to be solved and effects of the invention)
First, the problems to be solved by the invention and the effects of the invention are not limited to the above-described contents, and the present invention solves the problems not described above or has the effects not described above. There are also cases where only some of the described problems are solved or only some of the described effects are achieved.

(About heat exchange between steam gas and dry distillation gas by heat exchanger 50)
In the above embodiment, heat exchange is performed by the heat exchanger 50 between the steam gas that has passed through the steam gas cleaning tank 37a and the dry distillation gas that has passed through the exhaust gas oxidation device 45, but with a different arrangement. Heat exchange can also be performed. For example, heat exchange may be performed between the vapor gas discharged from the dryer 21 and the dry distillation gas that has passed through the exhaust gas oxidation device 45. In this case, in the steam gas processing system, the temperature of the steam gas is raised at a stage before being introduced into the dust collector 32. Therefore, the temperature of the dust collector 32 into which the heated steam gas is introduced is also maintained at a predetermined level or higher. Therefore, the dust collector 32 can be prevented from being blocked by oil or the like contained in the vapor gas.

  The polluted soil detoxification system according to the present invention can be applied to a system and method for detoxifying contaminated soil by reducing and heating the pollutant under reduced pressure, and in particular removes pollutants contained in exhaust gas from the drying device It is useful for a polluted soil detoxification system that can reliably purify the exhaust gas.

It is the schematic of a contaminated soil detoxification system. It is the figure which showed the outline of the structure of the dryer 21, FIG.2 (a) is a side view of the whole dryer 21, FIG.2 (b) is an enlarged view of the area | region A in Fig.2 (a), FIG. c) is an enlarged view of a region B in FIG. It is the figure which showed the outline of the structure of the pressure reduction heating apparatus 24, Fig.3 (a) is a side view of the whole pressure reduction reduction apparatus, FIG.3 (b) is an enlarged view of the area | region C in Fig.3 (a), figure. 3 (c) is an enlarged view of a region D in FIG. 3 (a). 3 is a side view showing an internal structure of a rotary furnace 24c of a reduced pressure reduction heating device 24. FIG. 3 is a side view of the cooling device 25. FIG. It is the schematic which represented the apparatus structure of the steam gas processing system | strain typically. It is the schematic which represented the apparatus structure of the dry distillation gas processing system | strain typically. 2 is a block diagram functionally conceptually showing an electrical configuration of a control panel 90. FIG. It is the flowchart which showed the flow of the contaminated soil detoxification process. It is the flowchart which showed the flow of the process of steam gas. It is the flowchart which showed the flow of the process of dry distillation gas. 7 is a flowchart showing a flow of a purification process of steam gas in the steam gas purification device 37.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Contaminated soil detoxification system 20 Soil hopper 21 Dryer 21a, 24a Combustion chamber 21b, 24b Heating part 21c, 24c Rotary furnace 21d, 24d, 25b Drive part 21e, 24e Exhaust outlet 21f, 24f, 25e Supply port 21g, 24g, 25f Discharge port 21h, 24h Hood 22 Blowing device 23 Conveying device 24 Reduced pressure reduction heating device 24i, 25g Feeding blade 24j Temperature measuring device 25 Cooling device 25a Rotating body 25c Water supply pipe 25d Water spray device 25h Water discharge head 25i Spray port 30 Steam gas piping 31 Emergency piping 32, 47 Dust collector 32a, 47a Cyclone type dust collector 32b, 47b Bag filter type dust collector 32c Thermal insulation jacket 33 Activated carbon supply device 34 Thermal insulation gas piping 35 Dust collection dust piping 35a Conveying air supply unit 36 Dust collection device 7 Steam gas purification device 37a Steam gas cleaning tank 37b Deodorizing catalyst device 39 Switching damper 40 Dry distillation gas piping 41 High temperature dust collector 42 Slaked lime supply device 43 Granulator 44 Bypass piping 45 Exhaust gas oxidation device 46 Exhaust gas cooling device 48 Desulfurization device 49 Switching damper 50 Heat exchanger 60 Activated carbon adsorption tank 70 Fuel supply device 80 Waste heat utilization piping 90 Control panel 91 Dryer control unit 92 Depressurization reduction heating device control unit 93 Cooling device control unit 94 Steam gas processing control unit 95 Distillation gas processing control unit 96 Input Part 97 Memory part 100 Chimney

Claims (4)

A polluted soil detoxification system that detoxifies the contaminated soil by decomposing pollutants contained in the contaminated soil,
A drying device for drying the contaminated soil;
A reduced pressure reduction heating apparatus for decomposing the contaminated soil dried by the drying apparatus by reduced pressure reduction heating;
Exhaust gas purification means for treating exhaust gas discharged from the drying device by drying the contaminated soil with the drying device, and purifying predetermined harmful substances contained in the exhaust gas When,
Contaminated soil detoxification system characterized by comprising The exhaust gas purification means includes an exhaust gas cleaning device that purifies the harmful substances by liquid cleaning the exhaust gas;
The polluted soil detoxification system according to claim 1. The exhaust gas purification means includes a catalyst device that purifies the harmful substance by bringing the exhaust gas into contact with a catalyst in a state where the exhaust gas is heated to a predetermined temperature or higher.
The contaminated soil detoxification system according to claim 1 or 2. The exhaust gas discharged from the reduced pressure reduction heating apparatus is treated by decomposing the pollutant in the contaminated soil by reduced pressure reduction heating with the reduced pressure reduction heating apparatus, and is contained in the exhaust gas. Exhaust gas combustion means for burning predetermined harmful substances;
Heat exchange is performed between the exhaust gas after combustion exhausted from the exhaust gas combustion means and the exhaust gas exhausted from the drying device or the exhaust gas from which at least a part of the harmful substances has been removed from the exhaust gas. A heat exchange device that raises the temperature of the exhaust gas discharged from the drying device,
Introducing the exhaust gas heated by the heat exchange device into the catalyst device;
The polluted soil detoxification system according to claim 3.

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