JP2009066494A - System for making contaminated soil harmless - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system 1 for making contaminated soil harmless capable of preventing a pyrolysis gas and dust from leaking through gaps between a rotary kiln and its hoods even if sucking force of sucking the pyrolysis gas, vapor and the like from inside the rotary kiln is decreased and the inner pressure thereof is increased. <P>SOLUTION: The system 1 for making contaminated soil harmless comprises a vacuum reduction-reactor/heater 24 for treating contaminants in contaminated soil and a sucking device for sucking dust discharged therefrom. The vacuum reduction-reactor/heater 24 is equipped with a feed port 24f for feeding contaminated soil thereinto or a discharge port 24g for discharging contaminated soil therefrom. The feed port 24f and the discharge port 24g are each equipped with a primary hood 24k that prevents a gas from directly flowing between the feed port 24f or discharge port 24g and outside. The primary hoods 24k are each covered with a secondary hood 24m that prevents a gas from directly flowing between each of the primary hoods 24k and outside. The sucking device is connected to the secondary hoods 24m. <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 a conventional processing system, a rotary kiln type heating furnace is often used as a heating furnace for performing reduced pressure reduction thermal decomposition dechlorination treatment. The rotary kiln type heating furnace has a cylindrical rotary furnace into which contaminated soil is charged. By heating the rotary furnace from the outside, the contaminated soil inside the rotary furnace can be heated. . At both ends of the rotary furnace, there are provided an inlet for introducing contaminated soil and an outlet for discharging the contaminated soil. By rotating these inlets and outlets with a hood, the rotary furnace can be rotated. The inside of the furnace is sealed.

  When performing reduced pressure reduction thermal decomposition dechlorination treatment of contaminated soil using this rotary furnace, while maintaining the inside of the rotary furnace in a reducing atmosphere, contaminants such as dioxin separated from the contaminated soil and scattered In order to discharge the dry distillation gas containing dust and the like from the rotary furnace, the dry distillation gas inside the rotary furnace is sucked from the outside by a pump or the like. Therefore, in a normal operation state, since the inside of the rotary furnace is in a reduced pressure state, the dry distillation gas and dust contained in the dry distillation gas do not leak to the outside through the gap between the rotary furnace and the hood. However, when the suction force for sucking dry distillation gas decreases due to troubles such as pump abnormalities and unexpected fluctuations in operating conditions, the internal pressure of the rotary furnace rises, and the dry distillation gas passes through the gap between the rotary furnace and the hood. Etc. could be leaked.

  Further, in the heating furnace of the dryer that heats and drys the contaminated soil, the same problem as described above occurs and there is a possibility that steam gas or the like leaks.

  The present invention has been made in view of the above, and even when the suction force for sucking dry distillation gas, steam gas or the like from the inside of the rotary furnace is reduced and the internal pressure of the rotary furnace is increased, the rotary furnace and the hood The purpose of the present invention is to provide a polluted soil detoxification system that can prevent the leakage of dry distillation gas and dust from the gap between them.

  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 contaminated soil treatment device for treating the pollutant of the contaminated soil, and suction means for sucking dust discharged from the contaminated soil treatment device, An inlet for introducing the contaminated soil into the contaminated soil treatment apparatus, or an outlet for discharging the contaminated soil treated by the contaminated soil treatment apparatus from the contaminated soil treatment apparatus, The inlet or the outlet is a first hood that communicates with the inlet or the outlet and prevents direct gas flow between the inlet or the outlet and the outside. And communicate with the first hood A second hood that prevents direct gas flow between the first hood and the outside, and the suction means is connected to the second hood. To do.

  Further, the polluted soil detoxification system according to claim 2 is the polluted soil detoxification system according to claim 1, wherein the dust collecting unit collects dust contained in the exhaust gas discharged from the polluted soil treatment apparatus. Means, and the dust sucked by the suction means is introduced into the dust collection means.

  In addition, the polluted soil detoxification system according to claim 3 is the polluted soil detoxification system according to claim 1 or 2, wherein the internal pressure of the contaminated soil treatment apparatus or the input port or the discharge port is Measuring means for measuring pressure, and suction control means for controlling the suction means to cause the suction to be performed when the pressure measured by the measuring means exceeds a predetermined pressure, To do.

  Further, the contaminated soil detoxification system according to claim 4 is the contaminated soil detoxification system according to any one of claims 1 to 3, wherein the contaminated soil treatment apparatus removes the contaminants of the contaminated soil. And a reduced pressure reduction heating apparatus that decomposes by reduced pressure reduction heating.

  According to the first aspect of the present invention, the first hood that covers the inlet or outlet in the contaminated soil treatment apparatus and the gap between the first hood and the inlet or outlet are covered. A second hood is provided, and suction means is connected to the second hood. Thereby, even if the internal pressure of the contaminated soil treatment device increases due to the occurrence of a trouble and the dust leaks from the first hood, the leaked dust flows into the second hood, and the second hood Therefore, it is possible to prevent leakage of dust and the like to the outside.

  According to the second aspect of the present invention, since dust or the like sucked from the second hood by the suction means is introduced into the dust collection means, the dust to which contaminants adhere is collected by the dust collection means. It can be collected and processed appropriately.

  According to the third aspect of the present invention, the internal pressure of the contaminated soil treatment apparatus is measured by the measuring means, and when the measured pressure value is equal to or higher than a predetermined reference pressure value, the suction control means is Since the suction means is operated and dust or the like is sucked from the inside of the second hood by the suction means, leakage of dust or the like to the outside can be prevented. Further, since it is not necessary to always operate the suction means to prevent leakage of dust and the like, it is possible to suppress an increase in operating cost.

  Further, according to the present invention described in claim 4, since the first hood, the second hood, and the suction means are provided for the reduced pressure reduction heating device, the internal pressure of the reduced pressure reduction heating device is Even when it rises, leakage of dry distillation gas containing contaminated dust to the outside can be prevented.

  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 characteristics of the contaminated soil detoxification system according to the embodiment is that, in general, in the contaminated soil treatment apparatus for detoxifying the contaminated soil, an inlet for introducing the contaminated soil or an outlet for discharging the contaminated soil A first hood for preventing direct gas flow between the inlet or outlet and the outside with respect to the outlet, and a direct between the first hood and the outside. A second hood for preventing gas flow is provided, and suction means for sucking dust, exhaust gas, and the like generated from the contaminated soil treatment apparatus is connected to the second hood. As a result, even if dust or the like leaks from the first hood, the leaked dust flows into the second hood, so that the dust can be sucked by the suction means, and leakage to the outside is prevented. be able to.

[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 first hood, the second hood, and the suction means, which are features of the contaminated 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 contaminated soil treatment apparatus 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 unit 21b heats the contaminated soil in the dryer 21. Specifically, the fuel is burned 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 duplex hood 21h is provided around the supply port 21f and the discharge port 21g so that dust from the contaminated soil and vapor gas evaporated and volatilized from the contaminated soil do not leak outside the dryer 21. Here, the supply port 21f corresponds to the input port in the claims. Details of the structure of the duplex hood 21h will be described later.

  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.

  Furthermore, a pressure sensor (not shown) is installed in the vicinity of the supply port 21f and the discharge port 21g inside the rotary furnace 21c. This pressure sensor measures the pressure inside the rotary furnace 21c, and corresponds to the measuring means in the claims. Data measured by the pressure sensor is output 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, and corresponds to the contaminated soil treatment device in the claims. 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. 3A is a side view of the whole reduced pressure reduction device (partially cut away), and FIG. 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 double hood 24h for preventing leakage of dry distillation gas is provided. Here, the supply port 24f corresponds to the input port in the claims. Details of the structure of the duplex hood 24h will be described later.

  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.

  Further, a pressure sensor (not shown) is installed in the vicinity of the supply port 24f and the discharge port 24g inside the rotary furnace 24c. This pressure sensor measures the pressure inside the rotary furnace 24c, and corresponds to the measuring means in the claims. Data measured by the pressure sensor is output to the control panel 90.

  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)
In FIG. 1, the steam gas processing system is a processing system for processing steam gas containing moisture evaporated from the contaminated soil dried in the dryer 21, and includes a steam gas pipe 30, an emergency pipe 31, and 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 collecting machine 36, a steam gas cleaning tank 37, and a deodorization catalyst device 38. 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 a temperature signal output from a steam gas temperature measuring device to be described later 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. 6, 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 cleaning tank 37)
The steam gas cleaning tank 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. Since dioxin is adsorbed to the dust, the dioxin can be removed from the steam gas by removing the dust with the steam gas cleaning tank 37. Although the specific configuration of the vapor gas cleaning tank 37 is arbitrary, for example, a wet scrubber that gas-liquid mixes the vapor gas and the cleaning liquid and collects dust with the atomized cleaning liquid can be used.

(Configuration of contaminated soil detoxification system-deodorization catalyst device 38)
The deodorization catalyst device 38 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 37. The deodorization catalyst device 38 oxidizes odor components, PCB, and the like contained in the vapor gas by bringing the vapor gas heated to a predetermined temperature or more into contact with the catalyst. In order to cause an oxidation reaction in the deodorization catalyst device 38, the high-temperature dry distillation gas that has passed through an exhaust gas oxidation device 45 described later in the dry distillation gas treatment system is heated through the heat exchanger 50 and becomes a predetermined temperature or higher. Steam gas is introduced into the deodorization catalyst device 38. Since the specific configuration of the deodorization catalyst device 38 is known, a description thereof will be omitted.

(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 system again by introducing the granules 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 oxidation device 45 is for subjecting organic chlorine-based contaminants 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. 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 processing system and the steam gas that has passed through the steam gas cleaning tank 37 in the steam gas processing system. It is. Although the specific structure of the heat exchanger 50 is arbitrary, for example, a radiant heat exchanger having a double cylinder of an inner cylinder and an outer cylinder can be used. 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. Further, the steam gas is heated to a temperature necessary for the catalytic reaction in the deodorizing catalyst device 38 in the subsequent stage by receiving heat from the dry distillation gas in the heat exchanger 50.

(Configuration of contaminated soil detoxification system-activated carbon adsorption tank 60)
In FIG. 1, in the activated carbon adsorption tank 60, a small amount of dust, odor, etc. remains in the vapor gas that has passed through the deodorization catalyst device 38 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 so, 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 deodorization catalyst device 38 and a desulfurization device 48 through 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, the blowing device 22, and a suction device described later. The reduced pressure reduction heating device control unit 92 controls the reduced pressure reduction heating device 24 and a suction device described later. 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 control unit 91, the temperature of the contaminated soil put into the dryer 21 is maintained within a predetermined temperature range, and the contaminated soil is dried (step SA-2). Details of the temperature control processing of the contaminated soil by the dryer control unit 91 will be described later. The contaminated soil dried by the dryer 21 is discharged from the dryer 21 (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 put into the rotary furnace 24c is heated from the combustion gas in the combustion chamber 24a through the furnace wall of the rotary furnace 24c and subjected to reduced pressure reduction heat treatment (step SA-6). Details of this reduced pressure reduction heat treatment will be described later.

  Contaminated soil that has completed the reduced pressure reduction heat treatment and has moved through the rotary furnace 24c to the outlet 24g is discharged from the outlet 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 cleaning tank 37 (step SB-6). In the steam gas cleaning tank 37, a very small amount of dust, dioxin and the like contained in the steam gas are removed (step SB-7).

  After passing through the steam gas cleaning tank 37, 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. Thereby, the vapor gas is heated up to a temperature necessary for the reaction in the deodorizing catalyst device 38 at the subsequent stage (step SB-8).

  The vapor gas heated in the heat exchanger 50 is introduced into the deodorization catalyst device 38 (step SB-9). When the vapor gas is introduced into the deodorization catalyst device 38, the catalyst of the deodorization catalyst device 38 promotes the oxidation reaction of odor components and PCBs contained in a small amount in the vapor gas, and the vapor gas is rendered harmless (step) SB-10).

  The vapor gas that has passed through the deodorization catalyst device 38 is introduced into the activated carbon adsorption tank 60 (step SB-11). When the vapor gas is introduced into the activated carbon adsorption tank 60, dust, odors, etc. remaining in a minute amount in the vapor gas are adsorbed and removed by the activated carbon (step SB-12). 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-13).

(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 from the reduced pressure reduction heating device 24 to the dry distillation gas pipe 40 (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 duplex hood 21h in the dryer 21)
Next, the structure of the duplex hood 21h in the dryer 21 will be described. As shown in FIGS. 2B and 2C, the duplex hood 21h includes a primary hood 21i, a secondary hood 21j, a local dust collector (not shown), and a suction device (not shown).

  The primary hood 21i prevents direct gas flow between the inside and the outside of the rotary furnace 21c, and corresponds to the first hood in the claims. The primary hood 21i is slidable with respect to the rotary furnace 21c so as to cover the supply port 21f and the discharge port 21g, respectively. A steam gas pipe 30 is connected to the primary hood 21i on the supply port 21f side. 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 primary hood 21 i on the discharge port 21 g side is connected to the transport device 23.

  The secondary hood 21j prevents direct gas flow between the inside and the outside of the primary hood 21i, and corresponds to the second hood in the claims. The secondary hood 21j is slidably provided with respect to the rotary furnace 21c so as to cover the gap between the primary hood 21i and the rotary furnace 21c, and is connected to a local dust collector (not shown) via a pipe 21k. Yes.

  The local dust collector collects dust contained in the exhaust gas sucked from the inside of the secondary hood 21j by the suction force of the suction device, and corresponds to the dust collecting means in the claims. The specific configuration of the local dust collector is arbitrary, and for example, a dust collector including a dioxin-compatible filter and an activated carbon adsorption layer can be used.

  The suction device sucks dust discharged through the primary hood 21i and the secondary hood 21j, and corresponds to the suction means in the claims. A local dust collector is disposed between the suction device and the secondary hood 21j.

  When the suction device is operated, the gas existing between the secondary hood 21j and the outer periphery of the rotary furnace 21c is sucked up to the local dust collector by the suction device, and the dust contained in the sucked gas becomes the local dust. After being removed by the dust collector, the gas is discharged to the atmosphere.

(Configuration of duplex hood 24h in reduced pressure reduction heating device 24)
Next, the structure of the duplex hood 24h in the reduced pressure reduction heating device 24 will be described. As shown in FIGS. 3B and 3C, the duplex hood 24h includes a primary hood 24k, a secondary hood 24m, a local dust collector (not shown), and a suction device (not shown).

  The primary hood 24k prevents direct gas flow between the inside and the outside of the rotary furnace 24c, and corresponds to the first hood in the claims. The primary hood 24k is provided slidably with respect to the rotary furnace 24c so as to cover the supply port 24f and the discharge port 24g, respectively. A dry hood gas pipe 40 is connected to the primary hood 24k on the supply port 24f side. The primary hood 24k on the discharge port 24g side is connected to the cooling device 25.

  The secondary hood 24m prevents direct gas flow between the inside and the outside of the primary hood 24k, and corresponds to the second hood in the claims. The secondary hood 24m is slidably provided with respect to the rotary furnace 24c so as to cover the gap between the primary hood 24k and the rotary furnace 24c, and is connected to a local dust collector (not shown) via a pipe 24n. Yes.

  The local dust collector collects dust contained in the exhaust gas sucked from the inside of the secondary hood 24m by the suction force of the suction device, and corresponds to the dust collecting means in the claims.

  The suction device sucks dust discharged through the primary hood 24k and the secondary hood 24m, and corresponds to the suction means in the claims. A local dust collector is disposed between the suction device and the secondary hood 24m.

  When the suction device is operated, the gas existing between the secondary hood 24m and the outer periphery of the rotary furnace 24c is sucked up to the local dust collector by the suction device, and the dust contained in the sucked gas is After being removed by the dust collector, the gas is discharged to the atmosphere.

(Temperature control processing of contaminated soil by the dryer control unit 91)
Next, the temperature control process of the contaminated soil by the dryer control unit 91 will be described. FIG. 12 is a flowchart showing the flow of the contaminated soil temperature control process by the dryer control unit 91.

  The contaminated soil transferred to the dryer 21 in Step SA-1 is introduced into the rotary furnace 21c through the supply port 21f (Step SD-1). The contaminated soil put into the rotary furnace 21c is heated from the combustion gas in the combustion chamber 21a through the furnace wall of the rotary furnace 21c. At this time, the dryer control unit 91 heats the rotary furnace 21c by the heating unit 21b based on the contaminated soil temperature measured by the temperature measuring instrument and the steam gas temperature measured by the steam gas temperature measuring instrument. Control the amount.

  Specifically, the dryer control unit 91 is measured by the steam gas temperature measuring device so that the temperature of the contaminated soil measured by the temperature measuring device on the discharge port 21g side is kept below a predetermined temperature. The heating unit 21b is controlled so that the temperature of the vapor gas is maintained at a predetermined temperature or higher.

  The amount of heating required to keep the contaminated soil in the above temperature range varies depending on the properties such as the moisture content of the contaminated soil that is input to the dryer 21 and the input amount. For this reason, the dryer control part 91 acquires operation information, such as properties, such as the moisture content of a contaminated soil, and input amount (step SD-2). This operation information can be acquired from, for example, a moisture meter or soil hopper 20 provided on the upstream side of the soil hopper 20 or the dryer 21, or stored in the storage unit 97 in advance by the operator. Then, the dryer control unit 91 determines the heating amount corresponding to the acquired operation information (step SD-3). For example, in the storage unit 97, the moisture content and other properties of the contaminated soil, the input amount, and the heating amount suitable for drying the contaminated soil and the temperature of the contaminated soil being below a predetermined temperature are mutually stored. Is stored in advance, the heating amount is determined with reference to this control table, and the heating unit 21b is controlled to perform heating of the determined heating amount (step SD-4). ).

  Furthermore, the dryer control unit 91 measures the temperature change for a predetermined time immediately after the introduction of the contaminated soil with a temperature measuring device, and the heating unit targeting the above temperature range according to the relationship between the measured temperature change rate and the heating amount. The prediction control of 21b is performed (step SD-5). That is, the dryer control unit 91 stores the heating amount determined in step SD-3 and the temperature of the contaminated soil measured by the temperature measuring instrument when the operation is performed at the heating amount in the storage unit 97 at predetermined intervals. Based on the stored operation history information, the trend analysis of the temperature of the contaminated soil with respect to the heating amount is performed, and the heating unit 21b is controlled with reference to the trend analysis result. For example, the slope of the change in the contaminated soil temperature relative to the amount of change in the heating amount is calculated, the delay time from the change in the heating amount to the corresponding change in the contaminated soil is specified, and these slopes and delay times are used as a reference. Then, an appropriate heating amount for the desired contaminated soil temperature is calculated, and the heating unit 21b is controlled by the calculated heating amount.

  The contaminated soil is heated by the heating unit 21b controlled in this way, the water contained in the contaminated soil evaporates, and the moisture content of the contaminated soil is reduced to less than 5%. When the temperature of the contaminated soil measured by the temperature measuring instrument is equal to or lower than the predetermined temperature (step SD-6, No), the dryer control unit 91 changes the state of the contaminated soil detoxification system 1 to the blowing device 22. While not being operated, the steam gas is maintained in a normal state where steam gas is introduced into the steam gas processing system (step SD-7).

  On the other hand, when the temperature of the contaminated soil measured by the temperature measuring instrument exceeds the predetermined temperature (step SD-6, Yes), the dryer control unit 91 shifts the state of the contaminated soil detoxification system 1 to the emergency state. (Step SD-8). Specifically, the blowing device 22 is operated, cooling gas is blown into the rotary furnace 21c to cool the contaminated soil, and the switching damper 39 in the steam gas processing system is operated by the steam gas processing control unit 94. Then, the steam gas is introduced into the dry distillation gas processing system via the emergency pipe 31. Thereafter, the dryer control unit 91 maintains the emergency state while the contaminated soil temperature exceeds the predetermined temperature (step SD-6, Yes). When the contaminated soil temperature is equal to or lower than the predetermined temperature (step SD-6, No), the dryer control unit 91 stops the blowing device 22, and the steam gas processing control unit 94 switches the switching damper 39 in the steam gas processing system. Is operated again to shift the contaminated soil detoxification system 1 to the normal state (step SD-7).

  Moreover, the dryer control part 91 acquires the output from the pressure sensor in the rotary furnace 21c of the dryer 21 with a predetermined period (step SD-8). Furthermore, the acquired pressure value is compared with a reference pressure value stored in the storage unit 97 (step SD-9). If the acquired pressure value is less than the reference pressure value (step SD-9, Yes), it is determined that no dust or the like leaks from the rotary furnace 21c to the outside, and the normal operation is continued (step SD-10). On the other hand, if the acquired pressure value is equal to or higher than the reference pressure value (step SD-9, No), it is determined that there is a possibility that dust or the like may leak from the rotary furnace 21c, and the suction device is operated. (Step SD-11). The suction device sucks the gas existing between the secondary hood 21j and the outer periphery of the rotary furnace 21c through the local dust collector, and collects the dust contained in the gas by the local dust collector. Moreover, in order to reduce the internal pressure of the rotary furnace 21c, the dryer control part 91 reduces the heating amount by the heating part 21b (step SD-12), and issues a warning by a predetermined warning means (step SD-13). ).

(Reduced pressure reduction heating process by reduced pressure reduction heating device controller 92)
Next, the reduced pressure reduction heat treatment in Step SA-6 will be described. FIG. 13 is a flowchart showing the flow of the reduced pressure reduction heat treatment. In order to separate organic chlorine-based pollutants such as dioxins and PCBs contained in the contaminated soil from the contaminated soil and heat them under reduced pressure, the temperature of the contaminated soil is about 570 ° C or higher, preferably about 670 ° C or higher. It is necessary to control the reduced pressure reduction heating device 24 so as to be held for 10 minutes or more. The amount of heating required to keep the contaminated soil within the above temperature range varies depending on the amount of contaminated soil input to the reduced pressure reduction heating device 24 and the like. For this reason, the reduced pressure reduction heating device control unit 92 acquires operation information such as the amount of contaminated soil input (step SE-1). This driving information can be acquired from the soil hopper 20, for example, or stored in the storage unit 97 in advance by the operator. And the reduced pressure reduction heating apparatus control part 92 determines the heating amount corresponding to the acquired driving | operation information (step SE-2). For example, the storage unit 97 correlates the input amount of the contaminated soil and the heating amount suitable for the reduced pressure reduction heat treatment of the contaminated soil and the temperature of the contaminated soil is about 570 ° C. or more. The control table configured as described above is stored in advance, the heating amount is determined with reference to this control table, and the heating unit 24b is controlled so as to heat the determined heating amount (step SE-3).

  Further, the control unit 92 of the reduced pressure reduction heating apparatus causes the temperature measuring device 24j to measure the temperature change for a predetermined time immediately after the contaminated soil is charged, and sets the temperature range based on the relationship between the measured temperature change rate and the heating amount. Predictive control of the heating unit 24b is performed (step SE-4). That is, the reduced pressure reduction heating device control unit 92 stores the heating amount determined in Step SB-2 and the temperature of the contaminated soil measured by the temperature measuring device 24j when the operation is performed with the heating amount in the storage unit 97. Stored as operation history information at predetermined intervals, based on the stored operation history information, a trend analysis of the temperature of the contaminated soil with respect to the heating amount is performed, and the heating unit 24b is controlled with reference to the trend analysis result. . For example, the slope of the change in the contaminated soil temperature relative to the amount of change in the heating amount is calculated, the delay time from the change in the heating amount to the corresponding change in the contaminated soil is specified, and these slopes and delay times are used as a reference. Then, an appropriate heating amount for the desired contaminated soil temperature is calculated, and the heating unit 24b is controlled by the calculated heating amount. Inside the rotary furnace 24c heated by the heating unit 24b, organic chlorinated contaminants such as dioxins and PCBs contained in the contaminated soil are separated from the contaminated soil and subjected to reduced pressure reduction heating. At this time, the dry distillation gas containing organic chlorine-based contaminants such as dioxins and PCB separated from the contaminated soil is discharged from the primary hood 24k on the supply port 24f side of the rotary furnace 24c to the dry distillation gas pipe 40.

  Moreover, the reduced pressure reduction heating apparatus control part 92 acquires the output from the pressure sensor in the rotary furnace 24c of the reduced pressure reduction heating apparatus 24 with a predetermined period (step SE-5). Further, the acquired pressure value is compared with the reference pressure value stored in the storage unit 97 (step SE-6). If the acquired pressure value is less than the reference pressure value (step SE-6, Yes), it is determined that no dust or the like leaks from the rotary furnace 24c to the outside, and the normal operation is continued (step SE-7). On the other hand, when the acquired pressure value is equal to or higher than the reference pressure value (step SE-6, No), it is determined that there is a possibility that dust or the like may leak to the outside from the rotary furnace 24c, and the suction device is operated. (Step SE-8). The suction device sucks the gas existing between the secondary hood 24m and the outer periphery of the rotary furnace 24c through the local dust collector, and collects the dust contained in the gas by the local dust collector. Further, the reduced pressure reduction heating device control unit 92 reduces the amount of heating by the heating unit 24b in order to reduce the internal pressure of the rotary furnace 24c (step SE-9), and issues a warning by a predetermined warning means (step SE). -10).

(Effect of embodiment)
Thus, according to the present embodiment, the primary hood 24k that covers the supply port f and the discharge port 24g in the rotary furnace 24c of the reduced pressure reduction heating device 24, and the gap between the primary hood 24k and the rotary furnace 24c are covered. A secondary hood 24m is provided, and a suction device is connected to the secondary hood 24m. Thereby, even if the internal pressure of the rotary furnace 24c increases due to the occurrence of a trouble and the dust leaks from the primary hood 24k, the leaked dust etc. flows into the secondary hood 24m and is sucked into the suction device. Therefore, it is possible to prevent the leakage of dust and the like to the outside.

  Further, since dust or the like sucked from the secondary hood 24m by the suction device is introduced into the local dust collector, the dust attached with the contaminants can be collected by the local dust collector and appropriately processed.

  Further, the internal pressure of the rotary furnace 24c of the reduced pressure reduction heating device 24 is measured by a pressure sensor, and when the measured pressure value is equal to or higher than a predetermined reference pressure value, the reduced pressure reduction heating device control unit 92 sets the suction device. Since it is operated and dust is sucked from the inside of the secondary hood 24m by the suction device, it is possible to prevent leakage of dust and the like to the outside. Moreover, since it is not necessary to always operate the suction device to prevent leakage of dust and the like, it is possible to suppress an increase in operating cost.

[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.

(Regarding the subject of the present invention)
In the above-described embodiment, it has been described that the dryer 21 and the reduced pressure reduction heating device 24 each include a duplex hood. However, only one of them may be configured to include a duplex hood. For example, only the reduced pressure reduction heating device 24 may be provided with a duplex hood. In this case, when the internal pressure of the rotary furnace 21c in the dryer 21 is abnormally increased, the internal pressure of the rotary furnace 21c is introduced by introducing the steam gas and dust inside the rotary furnace 21c into the dry distillation gas system through the emergency pipe 31. Can be reduced.

  The contaminated 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 contaminants under reduced pressure, and in particular, suction force for sucking dry distillation gas, steam gas, etc. Even when the internal pressure of the rotary furnace increases and the internal pressure of the rotary furnace increases, it is useful for a polluted soil detoxification system that can prevent leakage of dry distillation gas and dust from the gap between the rotary furnace and the hood.

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. It is the sectional side view which showed the structure of the dust collector 32 and the heat retention jacket 32c. 3 is a flowchart showing a flow of steam gas heating control in the dryer 21.

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 Duplex hood 21i, 24k Primary hood 21j, 24m Secondary hood 21k, 24n Piping 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 dust collector 32b, 47b Bag filter dust collector 32c Thermal insulation jacket 33 Activated carbon supply device 34 Hot gas piping 35 Dust collection dust piping 35a Carrying air supply machine 36 Dust collection dust recovery machine 37 Steam gas cleaning tank 38 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 Reduced pressure reduction heating device control unit 93 Cooling device control unit 94 Steam gas processing control unit 95 Dry distillation gas processing control unit 96 Input unit 97 Storage unit 100 Chimney

Claims (4)

A polluted soil detoxification system that detoxifies the contaminated soil by decomposing pollutants contained in the contaminated soil,
A contaminated soil treatment device for treating the contaminants of the contaminated soil;
A suction means for sucking dust discharged from the contaminated soil treatment device,
The contaminated soil treatment device is used for discharging the contaminated soil from the contaminated soil treatment device, or an inlet for introducing the contaminated soil into the contaminated soil treatment device. Has an outlet,
The input port or the discharge port communicates with the input port or the discharge port, and prevents a direct gas flow between the input port or the discharge port and the outside. A hood and a second hood that communicates with the first hood and prevents direct gas flow between the first hood and the outside;
Connecting the suction means to the second hood;
Contaminated soil detoxification system characterized by. A dust collecting means for collecting dust contained in the exhaust gas discharged from the contaminated soil treatment apparatus;
Introducing dust sucked by the suction means into the dust collection means;
The polluted soil detoxification system according to claim 1. Measuring means for measuring the internal pressure of the contaminated soil treatment apparatus, or the pressure of the inlet or the outlet;
A suction control means for controlling the suction means so that the suction is performed when the pressure measured by the measuring means exceeds a predetermined pressure;
The contaminated soil detoxification system according to claim 1, comprising: The contaminated soil treatment device is a reduced pressure reduction heating device for decomposing the contaminants of the contaminated soil by reduced pressure reduction heating;
The contaminated soil detoxification system according to any one of claims 1 to 3.

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