JP2010155214A - System for treating contaminated earth and sand - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for treating contaminated earth and sand which efficiently utilizes carbon dioxide generated in an actual site for cleaning of contaminated earth and sand. <P>SOLUTION: The system for cleaning earth and sand containing volatile materials and oil as contaminants includes an earth and sand receiving part 22, an additive agent feed part 23 feeding an additive agent containing at least one of slaked lime and quick lime, a mixing part 24 mixing the earth and sand from the earth and sand receiving part 22 with the additive agent from the additive agent feed part 23, a discharge part 25 discharging the earth and sand from the mixing part 24, a power device 26 having an engine 27, a moving body 1 supporting the earth and sand receiving part 22, the additive agent feed part 23, the mixing part 24 the discharge part 25 and the power device 26, a concentrator 30 enriching the concentration of carbon dioxide of exhaust gas from the power device 26, a reaction vessel 51 making the earth and sand loaded with the additive agent react to the exhaust gas enriched in the carbon dioxide concentration in the concentrator 30, and an exhaust gas feed pipe 3 feeding the exhaust gas to the reaction vessel 51 from the concentrator 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a contaminated earth and sand treatment system for purifying earth and sand containing at least one of volatile substances and oils as a contaminant.

When purifying contaminated earth and sand containing harmful substances, heating the contaminated earth and sand can increase the vapor pressure of the contaminant, lower the viscosity, and activate microorganisms in the earth and sand. As a method of applying heat to the contaminated earth and sand, quick lime (CaO) is added to the contaminated earth and sand, or the reaction heat between the moisture contained in the earth or sand and the added water and quick lime is given to the pollutant to volatilize the pollutant ( (Hot soil method) is known (see Patent Document 1). In addition, there is a method of promoting treatment by reacting slaked lime (Ca (OH) ₂ )) that has been added or generated after the hydration reaction of quicklime and carbon dioxide, and further adding heat associated with the carbonation reaction. Yes (see Patent Document 2 etc.).

Japanese Patent No. 2589002 JP-A-2005-144307

  On the other hand, in many sites where purification treatment of contaminated earth and sand is performed, a soil conditioner and a heavy machine for supplying earth and sand are operated to mix additives with the contaminated earth and sand. These on-site machines are equipped with engines that burn fossil fuels, and the engine exhaust gas contains carbon dioxide. If the carbon dioxide contained in the engine exhaust gas can be effectively used for the carbonation reaction of slaked lime, further improvement in processing efficiency and reduction of carbon dioxide emissions from the processing site can be expected.

  However, the carbon dioxide contained in the engine exhaust gas is about 1-15%, and even if the exhaust gas is supplied as it is to the contaminated earth and sand, the reaction heat accompanying carbonation of slaked lime is other than carbon dioxide, which accounts for the majority of the exhaust gas. There is also a problem that heat is not effectively transmitted to the target contaminated soil and sand.

  The present invention has been made in view of this, and an object of the present invention is to provide a contaminated earth and sand treatment system capable of effectively utilizing carbon dioxide generated in the field for promoting the purification treatment of the contaminated earth and sand.

  (1) In order to achieve the above object, the present invention provides a sediment receiving unit for receiving sediment to be treated in a contaminated sediment treatment system for purifying sediment containing at least one of a volatile substance or oil as a contaminant. An additive supply unit that supplies an additive containing at least one of slaked lime or quicklime, a mixing unit that mixes the earth and sand from the earth and sand receiving unit and the additive from the additive supply unit, and the mixing unit A discharge unit that discharges earth and sand from the vehicle, a power unit incorporating an engine, the earth and sand receiving unit, the additive supply unit, the mixing unit, the discharge unit, and a traveling body that supports the power unit, and the power unit Concentration means for increasing the carbon dioxide concentration of the exhaust gas from, a reaction vessel for reacting the earth and sand to which the additive has been added, and the exhaust gas whose carbon dioxide concentration has been increased by the concentration means, and the concentration means The exhaust gas having an increased carbon dioxide concentration, characterized in that an exhaust gas supply pipe for supplying into the reaction vessel.

  (2) In the above (1), preferably, the concentrating means has a polymer hollow membrane for separating the exhaust gas into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas, It is characterized by increasing the carbon dioxide concentration of the exhaust gas by separating it from the low-concentration carbon dioxide-containing gas with a vacancy membrane.

  (3) In the above (2), preferably, a heat exchanger for exchanging exhaust gas with earth and sand is provided upstream of the polymer hollow core membrane, and the earth and sand to be treated are heated by the heat exchanger while The exhaust gas supplied to the polymer hollow membrane is cooled.

  (4) In the above (1), preferably, the concentration means includes an absorption tower storing a solution that absorbs carbon dioxide in exhaust gas, and a regeneration tower that heats the solution from the absorption tower that absorbed carbon dioxide. The exhaust gas is separated into a low-concentration carbon dioxide-containing gas that has passed through the absorption tower and a high-concentration carbon dioxide-containing gas that has been heated in the regeneration tower and desorbed from the solution.

  (5) In any one of the above (2) to (4), preferably, a first exhaust pipe through which exhaust from the reaction vessel passes and a second exhaust through which the low-concentration carbon dioxide-containing gas passes from the concentrating means A pipe line and the first and second exhaust pipe lines are connected, and a merger in which the exhaust from the reaction vessel and the low-concentration carbon dioxide-containing gas are merged, and the gas mixed in the merger is released into the atmosphere An exhaust tower is provided.

  (6) In order to achieve the above-mentioned object, the present invention also provides an earth and sand receiving system for receiving earth and sand to be treated in a contaminated earth and sand treatment system for purifying earth and sand containing at least one of a volatile substance or oil as a pollutant. A mixing part for mixing and processing the additive material supply part for supplying an additive containing at least one of slaked lime or quick lime, the earth and sand from the earth and sand receiving part and the additive material from the additive material supply part, and the mixing A discharge unit that discharges the earth and sand from the unit, a power unit incorporating an engine, the earth and sand receiving unit, the additive supply unit, the mixing unit, the discharge unit, and a traveling body that supports the power unit, and the power An exhaust pipe for circulating the exhaust gas from the apparatus, a tank for storing a liquid for dissolving carbon dioxide in the exhaust gas from the exhaust pipe, and a carbon dioxide solution from the tank to the earth and sand Characterized in that a feed to the solution supply line.

  (7) In any one of the above (1) to (6), preferably, the earth and sand before mixing, or the earth and sand being mixed with or after mixing with the additive are used as exhaust heat and exhaust gas of the power unit. It is further characterized by further comprising means for heating at least one of them.

  (8) In any one of the above (1) to (7), preferably, an input heavy machine that inputs the earth and sand to be treated into the earth and sand receiving part, and an exhaust gas from a power device of the input heavy machine are supplied to the concentration means. And a supply pipe.

  According to the present invention, carbon dioxide generated in the field can be effectively used for promoting purification treatment of contaminated earth and sand.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
The contaminated earth and sand treatment system of the present invention purifies earth and sand containing at least one of a volatile substance (such as a volatile organic compound) or oil as a contaminant, and in this embodiment, as an additive Powdered slaked lime as a main component or additive material that is slaked lime is mixed with contaminated earth and sand by a self-propelled soil improvement machine, carbon dioxide contained in the engine exhaust of this self-propelled soil improvement machine is concentrated, Supply to mixed contaminated soil. The additive may contain quicklime.

Moreover, it is desirable to use slaked lime (Ca (OH) ₂ ) having a particle size as small as possible and a large specific surface area to be mixed with earth and sand and reacted with carbon dioxide. The slaked lime particles (lumps) react with carbon dioxide sequentially from the outside and change into calcium carbonate (CaCO ₃ ). Since the produced calcium carbonate is poorly water-soluble, the outer surface of the slaked lime particles (lumps) is coated with calcium carbonate at an early stage, leaving unreacted slaked lime at the center of the particles. In order to reduce the amount of slaked lime not subjected to the reaction as much as possible and increase the utilization efficiency of the slaked lime to efficiently heat the earth and sand, it is desirable that the particle size of the slaked lime added to the earth and sand is as small as possible.

Overall Configuration FIG. 1 is a conceptual diagram showing a main configuration of a contaminated earth and sand treatment system according to a first embodiment of the present invention.

  The contaminated earth and sand treatment system shown in FIG. 1 includes a self-propelled soil improvement machine 20 that mixes an additive with the contaminated earth and sand, a concentrator 30 that increases the carbon dioxide concentration of exhaust gas from the self-propelled earth improvement machine 20, and a self-propelled machine. Reactor 50 for reacting the earth and sand mixed with the additive with carbon dioxide in the soil type soil conditioner 20 and a loading heavy machine (not shown) such as a hydraulic excavator for throwing the soil to be treated into the self-propelled soil conditioner 20 And. The concentrator 30 and the reaction device 50 are configured separately from the self-propelled soil improvement machine 20, but may be mounted on the self-propelled soil improvement machine 20.

  The flow of sediment and exhaust gas in this system will be outlined. Exhaust gas discharged from the engine 27 of the self-propelled soil conditioner 20 (see FIG. 2 below) is led to the concentrator 30 via the exhaust pipe 1. It is burned. At that time, a part of the exhaust gas of the self-propelled soil conditioner 20 is released into the atmosphere through the flow divider 2 provided in the middle of the exhaust pipe 1. It is desirable that the flow rate divided by the flow divider 2 can be adjusted, and the amount of exhaust gas released to the atmosphere can be adjusted (the air emission side can also be shut off). When the exhaust gas from the engine of the input heavy machine is led to the concentrator 30 in addition to the exhaust gas of the self-propelled soil improvement machine 20, the exhaust pipe of the input heavy machine is connected to the flow divider 2 with a separate hose or the like. Thus, the exhaust gas on the input heavy machine side can be joined to the exhaust pipe 1.

  In the concentrator 30, as will be described later, the exhaust gas is separated into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas. The former is sent to the reactor 50 via the exhaust gas supply pipe 3, and the latter is the exhaust pipe. 4 to the merger 5. In addition to the exhaust pipe 4, an exhaust pipe 8 from the reaction device 50 is connected to the merger 5. A merger 6 is provided in the middle of the exhaust gas supply line 3. When necessary, a carbon dioxide cylinder 7 is connected to the merger 6 and carbon dioxide is additionally supplied to the exhaust gas supply line 3. can do. In the case where carbon dioxide is additionally supplied, a container storing dry ice may be provided instead of the cylinder 7 and the carbon dioxide sublimated in the container may be supplied to the merger 6.

  On the other hand, the earth and sand discharged by mixing with the additive in the self-propelled soil improvement machine 20 is supplied to the reactor 50, and the high-concentration carbon dioxide-containing gas (carbon dioxide concentration is led from the exhaust gas supply pipe 3). Elevated exhaust gas) and exhausted after reaction. The exhaust gas from the reactor 50 is guided to the merger 5 via the exhaust pipe 8. The exhaust pipe 8 is provided with a blower 9 and an adsorption tank 10 from the upstream side, and the blower 9 draws the atmosphere in the reaction apparatus 50 to generate a flow of the exhaust pipe 8, and the adsorption tank 10 having activated carbon. The harmful substances in the exhaust gas flowing through the exhaust pipe line 8 are adsorbed and removed by passing the gas through the exhaust pipe 8 and then sent to the merger 5.

  The exhaust gas from the reaction vessel 51 flowing through the exhaust pipe line 8 joins the low-concentration carbon dioxide-containing gas from the concentrator 30 flowing through the exhaust pipe line 4 in the merger 5 and then passes through the exhaust pipe 11. Released into the atmosphere. Since high-concentration carbon dioxide-containing gas and low-concentration carbon dioxide-containing gas are derived from exhaust gas and have a small amount of oxygen, if released into the atmosphere as it is, it may cause oxygen deficiency for workers around the system. The possibility of oxygen deficiency is reduced by adopting a configuration in which the carbon dioxide-containing gas is finally thoroughly mixed with the low-concentration carbon dioxide-containing gas and released to the atmosphere.

  Next, the schematic configuration of the main devices that make up the system will be described sequentially.

Self-propelled soil improvement machine 20
The self-propelled soil improvement machine 20 includes a traveling body 21, a sediment receiving unit 22 that receives sediment to be treated, an additive supply unit 23 that supplies additive to the sediment, and earth and sand and additive from the sediment receiving unit 22. A mixing unit 24 that mixes the additive from the supply unit 23, a discharge unit 25 that discharges earth and sand from the mixing unit 24, and a power unit 26 that incorporates an engine 27 (see FIG. 2) are provided.

  Although not shown in detail, the traveling body 21 includes a track frame, a driven wheel provided on one side of the track frame (for example, the left side in FIG. 1), and the other side of the track frame (for example, in FIG. 1). A driving wheel provided on the right side), a crawler belt hung around the driven wheel and the driving wheel, and a main body frame provided on the track frame. The earth and sand receiving part 22, the additive supply part 23, the mixing part 24, the discharge part 25 and the power unit 26 are supported by the main body frame of the traveling body 21.

  The earth and sand receiving unit 22 includes an earth and sand hopper provided on one side in the longitudinal direction of the main body frame (for example, the left side in FIG. 1), and a transport conveyor that extends from the lower side of the earth and sand hopper to the entrance to the earth and sand of the mixing unit 24. Yes. In some cases, a sieving device for removing foreign substances from the earth and sand is provided on the upper part of the earth and sand hopper.

  The additive supply unit 23 includes an additive hopper disposed above the mixing unit 24 and a feeder provided at a lower portion of the additive hopper. The additive material stored in the additive material hopper is discharged by a predetermined amount by the feeder and supplied to the earth and sand in the transport conveyor of the earth and sand receiving unit 22 or the earth and sand in the mixing unit 24. A so-called rotary feeder (rotary valve), a screw feeder, or the like is used as the feeder. The rotary feeder rotates the rotor with a plurality of partition walls on the rotating shaft to drop the additive material introduced into each room between the partition walls. The screw feeder rotates the auger and conveys it to the outlet of the additive material It will be discharged. The screw feeder has an advantage that, when a large amount of additive material is supplied, the error of the actual additive material supply amount with respect to the command value is smaller than that of the rotary feeder.

  The mixing unit 24 is a so-called mixing-type mixing device having a paddle mixer attached to a rotating shaft with a plurality of paddles, and is provided on a central portion in the longitudinal direction of the main body frame. The earth and sand introduced from the inlet of the earth and sand are mixed in the paddle mixer while being mixed by the paddle mixer and transferred in the axial direction and discharged from the outlet. This mixing unit can also use a so-called crushing type mixing device that crushes and mixes the falling earth and sand together with the additive with a cutter or striker rotating at high speed.

  The discharge unit 25 is a conveyor that conveys the earth and sand discharged from the outlet of the mixing unit 24 and discharges it to the outside of the machine. The discharge unit 25 is arranged to have an upward slope from below the outlet of the mixing unit 24 toward the tip. In the present embodiment, the earth and sand discharged from the discharge unit 25 is supplied to the reactor 50.

  In addition to the engine 27 (see FIGS. 2 and 3) as a power source, the power unit 26 is a control valve that supplies a pump driven by the engine 27 and pressure oil discharged from the pump to a hydraulic actuator in each part of the machine body. Built-in unit.

Reactor 50
The reactor 50 includes a reaction vessel 51 for reacting the earth and sand added with the additive in the self-propelled soil improvement machine 20 and the exhaust gas having a higher carbon dioxide concentration in the concentrator 30, and the earth and sand reacted with the exhaust gas in the reaction vessel. 51, and a discharge conveyor 52 for discharging outside. A stirring means 53 for stirring the earth and sand is provided in the lower part of the reaction vessel 51. Various stirring devices can be used for the stirring means 53. In this embodiment, the same paddle mixer as that used in the mixing unit 24 of the self-propelled soil improvement machine 20 is used. In the case of a paddle mixer, the effect of contact with carbon dioxide in the reaction vessel 51 is good because it involves the action of changing the upper and lower layers of the earth and sand in the reaction vessel 51.

  The reaction vessel 51 has a box shape in which desired airtightness is ensured except for the discharge portion 25 of the self-propelled soil improvement machine 20, each connection portion of the exhaust gas supply pipe line 3 and the exhaust pipe line 8, and the outlet of the earth and sand. Or it is a cylindrical container. The connection part of the exhaust gas supply line 3 is preferably as low as possible in the reaction vessel 51, and is preferably positioned lower than the surface layer of earth and sand deposited in the reaction vessel 51. In this case, the exhaust gas supply pipe 3 can be directly connected to an appropriate position of the reaction vessel 51 to send the exhaust gas to the reaction vessel 51, or the rotation shaft of the stirring means 53 can be arranged on the outer peripheral surface. By using a hollow pipe having a blow hole, it is possible to connect the exhaust gas supply pipe 3 to the rotating shaft of the stirring means 53 and send the exhaust gas into the reaction vessel 51 through the stirring means 53. . The former is provided with a discharge hole for exhaust gas on the side wall of the reaction vessel 51, so that the discharge hole is difficult to block with earth and sand, and the latter has an advantage that exhaust gas can be efficiently supplied into the flow of earth and sand during stirring. . When providing the fumarole hole on the rotating shaft of the agitating means 51, a filter for preventing infiltration of earth and sand into the rotating shaft can be provided on the fumarole hole. Moreover, in this Embodiment, although the reaction container 51 provided with the stirring means 53 and the discharge conveyor 52 is illustrated in this way, it can also replace with a fluidized bed reactor, for example.

  The discharge conveyor 52 is provided in the lower part of the reaction container 51, and discharges the sediment deposited in the reaction container 51 sequentially or at regular intervals. As for the structure of the discharge conveyor 52 and the reaction container 51, the lower part of the reaction container 51 is opened and the sediment in the reaction container 51 is received by the discharge conveyor 52, and the reaction container 51 and the discharge conveyor 52 are configured separately. Therefore, it is possible to receive the earth and sand discharged from the stirring means 53 by the discharge conveyor 52 and convey it. In addition, a belt conveyor or a screw conveyor can be used as the discharge conveyor 52, but when the earth and sand in the reaction vessel 51 are received by the discharge conveyor 52, the screw conveyor is more suitable for the reaction vessel 51 than the belt conveyor. This is advantageous for improving airtightness, and the stirring means 53 can be omitted when the stirring effect by the screw is sufficient. In the case where the earth and sand in the reaction vessel 51 are transported by a screw conveyor, the exhaust gas supply pipe 3 is connected to the rotating shaft of the screw conveyor, and the exhaust gas is supplied into the reaction vessel 51 via the rotating shaft of the screw conveyor. It can also be.

Concentrator 30
FIG. 2 is a schematic configuration diagram of a configuration example of the concentrator 30.

  This configuration example is an example in which the carbon dioxide concentration of the exhaust gas from the power unit 26 is increased using a membrane separation system. In this figure, the merger 6 and the blower 9 in the exhaust gas supply line 3 are not shown.

  The concentrator 30 shown in FIG. 2 has a particle filter 31 that removes dust in the exhaust gas from the self-propelled soil conditioner 20, a compressor 32 that compresses the exhaust gas, and dust in the compressed exhaust gas. Further, a particle filter 33 to be removed, a dryer 34 for drying the exhaust gas to remove moisture in the exhaust gas, and a polymer hollow membrane 35 for separating the exhaust gas into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas. Are provided in this order from the upstream side in the flow direction of the exhaust gas.

The high-concentration carbon dioxide-containing gas separated by the polymer hollow membrane 35 contains carbon dioxide (CO ₂ ) and oxygen (O ₂ ) as main components and is sent to the exhaust gas supply pipe 3. The higher the concentration of carbon dioxide in the high-concentration carbon dioxide-containing gas, the better as the efficiency of carbonation treatment of slaked lime in the latter stage is considered. However, for example, a sufficient effect can be expected even at about 50%. One of the low-concentration carbon dioxide-containing gases is mainly composed of nitrogen (N ₂ ) and is sent to the exhaust pipe 4. Further, the latter particle filter 33 may be the same as the previous particle filter 31, but in order to remove dust that could not be removed by the particle filter 31, the particle filter 33 having a smaller mesh size than the particle filter 31 in the present embodiment. Is used.

  In addition, when the separation membrane type concentrator 30 is used as shown in FIG. 2, it comes into contact with the earth and sand in the processing system of the self-propelled soil improvement machine 20 or the sand before being put into the self-propelled soil improvement machine 20. It is preferable to provide a heat exchanger 36 and to connect the exhaust pipe 1 from the self-propelled soil conditioner 20 to the concentrator 30 via the heat exchanger 36. The earth and sand in the self-propelled processing system includes earth and sand in the hopper of the earth and sand receiving unit 22, earth and sand on the transport conveyor of the earth and sand receiving unit 22, earth and sand in the mixing unit 24, and earth and sand on the discharge unit 25. The low-temperature earth and sand before the reaction with the additive is preferable. In that sense, the earth and sand in the hopper of the earth-and-sand receiving unit 22 or on the conveyor is good.

  By providing the heat exchanger 36 for exchanging the exhaust gas with the earth and sand upstream of the polymer hollow core membrane 35 in this way, while heating (preheating) the earth and sand to be treated, The exhaust gas supplied to the polymer hollow core membrane 35 can be cooled to protect the polymer hollow core membrane 35 from heat.

  In FIG. 2, the exhaust gas of the engine 27 of the self-propelled soil improvement machine 20 is cooled by the earth and sand in the heat exchanger 36, and then entirely or partially introduced into the concentrator 30 through the flow divider 2. The exhaust gas introduced into the concentrator 30 is dust-removed by the particle filter 31 and compressed by the compressor 32 to be increased in pressure, and then dust is removed again by the particle filter 33 and water is removed by the dryer 34. The exhaust gas that has undergone these steps is sent to the polymer hollow membrane 35 at a high pressure, and is divided into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas by the molecular sieving effect of the polymer hollow membrane 35.

  That is, the concentrator 30 in FIG. 2 is a mechanism that increases the carbon dioxide concentration of the exhaust gas by separating the exhaust gas from the low-concentration carbon dioxide-containing gas by the polymer hollow membrane 35.

  FIG. 3 is a schematic configuration diagram of another configuration example of the concentrator 30.

  This configuration example is an example in which the carbon dioxide concentration of exhaust gas from the power unit 26 is increased using a carbon oxide absorbent. In this figure, the merger 6 and the blower 9 in the exhaust gas supply line 3 are not shown.

  The concentrator 30 shown in FIG. 3 stores a heat exchanger 37 that cools the exhaust gas from the engine 27 of the self-propelled soil improvement machine 20 and a solution that absorbs carbon dioxide in the exhaust gas (for example, an aqueous amine solution). An absorption tower 38, a regeneration tower 39 for heating a carbon dioxide-rich solution from the absorption tower 38 that has absorbed carbon dioxide, a heater 40 for heating the regeneration tower 39, and a carbon dioxide-rich solution from the absorption tower 38. And a heat exchanger 41 for exchanging heat from the low carbon dioxide content solution from the regeneration tower 39.

  In FIG. 3, the exhaust from the engine 27 of the self-propelled soil conditioner 20 is circulated through the exhaust pipe 1 by the blower 42, and all or part of the exhaust is sent to the concentrator 30 via the flow divider 2. The exhaust gas supplied to the concentrator 30 flows through the heat exchanger 37 and exchanges heat with the heater 40 of the regeneration tower 39 to lower the heat, and is then sent to the absorption tower 38 where carbon dioxide is absorbed by the aqueous amine solution. The The exhaust gas that has passed through the absorption tower 38 is sent to the exhaust pipe 4 as a low-concentration carbon dioxide-containing gas, and the carbon dioxide-rich solution that has absorbed carbon dioxide in the absorption tower 38 is preheated through the heat exchanger 41. It flows into the regeneration tower 39. The high carbon dioxide-containing solution that has flowed into the regeneration tower 39 is heated to a desired temperature (for example, about 110 to 130 ° C.) by the heater 40, whereby gas such as carbon dioxide is desorbed from the solution. The gas containing a large amount of desorbed carbon dioxide is fed into the exhaust gas supply pipe 3 as a high-concentration carbon dioxide-containing gas, and the low carbon dioxide-containing solution from which carbon dioxide has been desorbed in the regeneration tower 39 is converted into a heat exchanger 41. Then, heat is applied to the carbon dioxide-rich solution from the absorption tower 38 to return to the absorption tower 38.

  That is, the concentrator 30 in FIG. 3 exhausts the low-concentration carbon dioxide-containing gas that has passed through the absorption tower 38 and the high-concentration carbon dioxide-containing gas that has been heated in the regeneration tower 39 and desorbed from the high-carbon dioxide content solution. This is a mechanism for separating gases. Although not shown in FIG. 3, the high-concentration carbon dioxide-containing gas from the concentrator 30 in FIG. 3 is sent to the exhaust gas supply pipe 3, and the low-concentration carbon dioxide-containing gas is sent to the exhaust pipe 4. 2 circulates in the same manner as the concentrator 30 and finally joins and is released into the atmosphere.

Description of Operation When the earth and sand to be treated is introduced into the hopper of the earth and sand receiving unit 22 of the automatic soil improvement machine 20 by the input heavy machine, the earth and sand are supplied to the mixing unit 24 by the transport conveyor. At that time, the additive is supplied from the additive supply device 23 to the earth and sand, and the additive is supplied to the mixing unit 24 together with the earth and sand. The earth and sand sufficiently mixed with the additive in the mixing unit 24 is conveyed by the discharge unit 25 and supplied to the reaction vessel 51 of the reaction apparatus 50.

  On the other hand, at least all or part of the exhaust gas of the engine 27 of the self-propelled soil improvement machine 20 among the self-propelled soil improvement machine 20 and the input heavy machine is introduced into the concentrator 30 via the exhaust pipe 1. Separated into high-concentration carbon dioxide-containing gas and low-concentration carbon dioxide-containing gas. The high-concentration carbon dioxide-containing gas flows through the carbon dioxide supply pipe 3 and is supplied to the reaction vessel 51 of the reaction apparatus 50 after merging with carbon dioxide from the cylinder 7 if necessary.

  In the reaction vessel 51, the earth and sand mixed with the additive in the self-propelled soil conditioner 20 are further stirred by the stirring means 53, and contacted with the exhaust gas whose carbon dioxide concentration is increased by the concentrator 30, and are discharged by the discharge conveyor 52. It is discharged outside the reactor 50. The discharged earth and sand are accumulated and cured at a predetermined place.

  Exhaust gas from the reaction vessel 51 is guided to the merging device 5 after removing harmful substances in the adsorption tank 10, and is sufficiently supplied with the low-concentration carbon dioxide-containing gas from the concentrator 30 guided through the exhaust pipe 4 there. Mixed and released into the atmosphere.

  As described above, in the present embodiment, after the earth and sand containing the contaminant to be purified is sufficiently mixed with the additive, it reacts with the exhaust gas having an increased concentration of carbon dioxide.

At this time, the carbon dioxide in the exhaust gas comes into contact with the slaked lime of the additive, and the reaction expressed by the following (Equation 1) occurs, the temperature of the earth and sand rises due to the reaction heat, and the volatile pollutants in the earth and sand Is detached from the earth and sand.
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O + 68.63 kj / mol (Formula 1)
Carbon dioxide introduced into the reaction vessel 51 may be dissolved in the water generated in (Equation 1).

Action Effect The carbon dioxide concentration of the engine exhaust gas of the self-propelled soil improvement machine 20 and the input heavy machine is about 1 to 15%, and most of the exhaust gas is occupied by a gas other than carbon dioxide such as nitrogen. Therefore, even if the engine exhaust gas is allowed to react with slaked lime as it is, the reaction between slaked lime and carbon dioxide proceeds, but most of the reaction heat is transferred to a gas other than carbon dioxide and is not transferred to pollutants. May be discharged.

  Therefore, in the present embodiment, the carbon dioxide concentration of the exhaust gas is increased before being supplied to the reaction vessel 51, and components other than carbon dioxide in the exhaust gas are reduced, so that they are conducted to pollutants in the earth and sand. The rate of heat of reaction can be increased. In this way, carbon dioxide contained in the engine exhaust gas of machines operating on site reacts with slaked lime, and the reaction heat is efficiently conducted to the contaminated earth and sand, increasing the vapor pressure and viscosity of the pollutants in the earth and sand. The effect of microbial activity in the earth and sand can be obtained, and contaminants can be desorbed and reduced from the earth and sand.

  Further, carbon dioxide contained in the engine exhaust gas is fixed by reacting with slaked lime and remains in the earth and sand, so that the amount of carbon dioxide released to the atmosphere can be reduced. Therefore, the carbon dioxide generated in the field as described above can be effectively used for promoting the purification treatment of contaminated earth and sand, and a high effect can be expected as a countermeasure against global warming.

  Moreover, the volatilization process of a pollutant can be accelerated | stimulated by preheating the earth and sand to be processed with the heat which the exhaust gas from self-propelled earth and sand improvement machine 20 grade | etc., Has. In the case of a self-propelled soil conditioner, compared to a fixed plant type soil conditioner, the soil receiving part, the additive supply part, the mixing process part, The discharge unit, its own power source, and the like must be mounted on the traveling body, and each device is densely arranged on the traveling body, and the flow of earth and sand and additive material is generated in a narrow space. Therefore, by applying the present invention to a self-propelled soil improvement machine, the piping path through which the exhaust gas or the like passes may be short, and the heat of the exhaust gas or the like can be effectively used for the purification treatment of the contaminated earth and sand.

  Furthermore, since the self-propelled soil improvement machine 20 and the input heavy equipment are moved from time to time, the heat of the exhaust gas can be used effectively, and the carbon dioxide contained in the exhaust gas can be used and fixed. It wasn't. On the other hand, in the present embodiment, it is applied to the work of mixing and carbonating the additive with the pollutant, and by using the exhaust gas as a heat source for promoting the volatilization of the pollutant in the contaminated earth and sand, Utilization of exhausted heat and utilization / immobilization of carbon dioxide can be performed simultaneously. Further, it is not necessary to separately provide a source of carbon dioxide necessary for carbonation, and the necessary carbon dioxide can be produced in the system, so that the effect of making the system compact can also be obtained.

  Also, as shown in FIG. 2, when a polymer hollow membrane is used to increase the carbon dioxide concentration of the exhaust gas, if the exhaust gas is introduced into the polymer hollow membrane at a high temperature, There is concern about thermal effects. Therefore, it is necessary to cool the exhaust gas etc. to some extent before being led to the polymer hollow core membrane, but it is possible to heat the soil to be treated by exchanging heat with the sand etc. before exhausting the polymer hollow core membrane. The exhaust gas can also be cooled and can be used effectively without throwing away the heat of the exhaust gas.

  In addition, the exhaust from the reaction vessel 51 may contain a high concentration of carbon dioxide in addition to contaminants. Contaminants are adsorbed and removed in the adsorption tank 10, but if the exhaust gas that has passed through the adsorption tank 10 is released to the atmosphere as it is, the oxygen concentration around the system may be lowered. Therefore, this point can be addressed by thoroughly mixing with the low-concentration carbon dioxide-containing gas from the concentrator 30 in which nitrogen or the like is the majority and then releasing the exhaust gas after the reaction into the atmosphere.

Furthermore, the calorific value of the reaction between slaked lime and carbon dioxide is equivalent to the hydration reaction of quick lime represented by the following (Formula 2).
CaO + H ₂ O → Ca (OH) ₂ +65.15 kj / mol (Formula 2)
When the reaction heat of (Equation 2) is used for heating the contaminated earth and sand, when there is not enough water in the earth and sand for the input of quick lime to complete the reaction of (Equation 2), water is separately added to the earth and sand. It is necessary to supply. As a result, the reaction of (Formula 2) proceeds, but the heat of hydration reaction is conducted to a large amount of feed water, and the earth and sand may not be efficiently heated.

  On the other hand, since it is not necessary to add water to the earth and sand in the reaction of the above (formula 1), the water content of the earth and sand after the reaction can be suppressed, and the reaction heat taken away by the water can be reduced. There may be a case where a very small amount of water is necessary for promoting the reaction of the above (Formula 1), but it is sufficient to have water originally contained in the earth and sand, and it is not necessary to add water to the earth and sand.

<Second Embodiment>
FIG. 4 is a conceptual diagram showing the main configuration of a contaminated earth and sand treatment system according to the second embodiment of the present invention.

  This embodiment is an example in which quick lime powder or powder containing quick lime as a main component is used as an additive to be mixed with earth and sand and slaked lime generated by quick lime hydration is used for reaction with carbon dioxide. The additive may contain slaked lime. Also in this embodiment, the smaller the particle size of the additive is, the better.

  In the present embodiment, when the amount of water in the earth and sand is small relative to the amount of quicklime added, a water amount 28 is appropriately provided to add an amount of water necessary for completing the hydration reaction to the additive or the earth and sand. The hydration means 28 can be configured, for example, to transport and spray water from a water storage tank using gravity or a pump. Examples of the locations where water is sprayed include the earth and sand hopper of the earth and sand receiving unit 22, the earth and sand inlet of the mixing unit 24, and the additive hopper of the additive material supply device 23 in some cases. The case where water is sprayed from the entrance of the section 24 to the earth and sand is illustrated. Other configurations are the same as those of the contaminated earth and sand treatment system of the first embodiment, and the flows of earth and sand, additives, and exhaust gas are also the same as those of the first embodiment.

  In the case of the present embodiment, by mixing quick lime with earth and sand, the hydration reaction between the moisture in earth and sand or the moisture added by the hydration means 28 and quick lime occurs, and water as shown in (Equation 2) above. Slaked lime is produced sequentially with the heat of reaction. Therefore, when exhaust gas is supplied to the earth and sand mixed with the additive, slaked lime generated by the hydration reaction and carbon dioxide react with each other, and reaction heat is generated together with calcium carbonate as shown in the above (Equation 1).

  Also in this embodiment, by increasing the carbon dioxide concentration of the exhaust gas supplied to the earth and sand, the reaction heat of carbon dioxide and slaked lime can be efficiently conducted to the earth and sand, as in the first embodiment. The effect of can be obtained. In addition, compared with the conventional purification process in which the contaminated sediment is heated only by the hydration reaction heat of quicklime, in this embodiment, by supplying carbon dioxide, it is equivalent to the hydration reaction heat as described above (Formula 1). Thus, the amount of quicklime added to obtain the same calorific value in total can be reduced. In the present embodiment, the amount of slaked lime produced is the same as that of only the hydration heat of quick lime, but since calcium carbonate is produced from slaked lime, there is also an advantage that the pH of the soil after the treatment does not increase.

<Third Embodiment>
FIG. 5 is a conceptual diagram showing a main configuration of a contaminated sediment treatment system according to the third embodiment of the present invention. Parts similar to those of the above-described embodiment are denoted by the same reference numerals as those of the above-described drawings, and description thereof is omitted.

  The present embodiment is an example in which carbon dioxide is dissolved in a liquid such as water, and a solution in which carbon dioxide is concentrated is mixed with earth and sand.

  The self-propelled soil improvement machine 20, the exhaust pipe 60 that distributes the exhaust gas from the engine 27 in the power unit 26 of the self-propelled soil improvement machine 20, and the carbon dioxide of the exhaust gas from the exhaust pipe 60 A tank 61 for storing a liquid to be dissolved (water or the like) and a solution supply pipe 62 for supplying the carbon dioxide solution from the tank 61 to the earth and sand are provided.

  For example, the solution supply pipe 62 may be configured such that the carbon dioxide solution in the tank 61 is gravity transported and sprinkled, but if necessary, the carbon dioxide solution from the tank 61 may be transported by a pump or the like. . Locations where the carbon dioxide solution is sprayed include the earth and sand hopper of the earth and sand receiving unit 22, the inlet of earth and sand of the mixing unit 24, and in some cases, the additive hopper of the additive supply device 23 and the like. The case where a carbon dioxide solution is sprayed on earth and sand from 24 entrances is illustrated. In the present embodiment, since the low-concentration carbon dioxide-containing gas is not generated in the carbon dioxide concentration step, the merger 5 in the exhaust pipe line 8 from the tank 61 is omitted. Other configurations are the same as those of the contaminated earth and sand treatment system of the first or second embodiment.

  In the present embodiment, the additive containing at least one of slaked lime or quick lime is mixed with the contaminated earth and sand while the exhaust gas from the engine 27 is sent to the tank 61 and the liquid in the tank 61 is discharged with the dioxide dioxide of the exhaust gas. Dissolve carbon and spray carbon dioxide solution on the earth and sand. The earth and sand are sufficiently mixed with the additive and the carbon dioxide solution in the mixing section 24, and the slaked lime in the additive and the slaked lime produced by the hydration reaction of quick lime react with the carbon dioxide in the carbon dioxide solution, Soil contaminants are removed by the reaction heat of (Formula 1). If quick lime is contained in the additive, this water can be used for the hydration reaction of quick lime by using water for the liquid in the tank 61.

  Also according to this embodiment, carbon dioxide is dissolved in a liquid, and the same effect as that of the first and second embodiments can be obtained by supplying a solution in which carbon dioxide is concentrated to earth and sand. Further, the system can be simplified as compared with the case of using the concentrator 30 of FIG. 2 or FIG.

<Fourth embodiment>
FIG. 6 is a conceptual diagram showing the main configuration of a contaminated earth and sand treatment system according to the fourth embodiment of the present invention. Parts similar to those of the above-described embodiment are denoted by the same reference numerals as those of the above-described drawings, and description thereof is omitted.

  The present embodiment is an example in which the exhaust gas of the engine 27 is used as a heating source for contaminated earth and sand before carbon dioxide concentration. The atmosphere in the power unit 26 heated by the exhaust heat of the engine 27 can be used as a heating source together with the exhaust gas. Alternatively, the exhaust pipe of the engine 27 may be sent separately from the exhaust gas pipe, and the exhaust gas may be sent directly from the engine 27 to the concentrator 30 to use only the exhaust heat for heating the earth and sand.

  In the present embodiment, a heat exchanger 71 provided in the earth and sand receiving unit 22 (for example, inside the hopper, the outer wall surface of the hopper, or the inside of the conveyor belt of the conveyor), and the exhaust gas extending from the power unit 26 and passing through the heat exchanger 71. The pipe 1a, the heat exchanger 72 provided in the discharge unit 25 (for example, the inside of the conveyor belt), the exhaust pipe 1a extending from the power unit 26 and passing through the heat exchanger 72, and the exhaust pipes 1a and 1b merge. And the exhaust pipe 1c connected to the concentrator 30 from the junction 73 via the shunt 2, and the exhaust pipe 1 of the first or second embodiment is omitted. The installation locations of the heat exchangers 71 and 72 can be changed as appropriate. For example, the exhaust pipe may be passed through the inside or outer wall surface of the casing of the mixing unit 24 or inside the paddle mixer of the mixing unit 24. Other configurations are the same as those in the first or second embodiment, and the exhaust gas of the engine 27 is dissolved in a liquid to concentrate carbon dioxide and react with slaked lime, which is the same as in the above-described embodiment. An effect can be obtained.

  In the present embodiment, at least one of the exhaust heat and exhaust gas of the engine 27 is heat-exchanged with the earth or sand before mixing, or the earth or sand during or after mixing with the additive, to heat the earth or additive. And further promote the purification process of pollutants. Thus, by transferring high-temperature heat immediately after exiting the engine 27 to the earth or sand or additive, the earth or sand or additive can be heated with high efficiency. The heat exchangers 71 and 72 of the present embodiment correspond to the heat exchanger 36 of FIG. 2, but the present embodiment can also be applied when the concentrator 30 of FIG. 3 is used.

  Further, when the configuration is further simplified, instead of piping the exhaust pipes 1a and 1b, a part of the exhaust gas supplied to the concentrator 30 may be diverted and directly sprayed onto the contaminated earth or additive. . Alternatively, the exhaust gas or the like may be directly blown to the sand or additive in the container such as the additive in the additive hopper or the earth and sand in the mixing unit 24, and then guided to the concentrator 30. When the exhaust gas or the like is blown onto the earth and sand and then guided to the concentrator 30, there is a possibility that contaminants desorbed from the earth and sand are sent into the concentrator 30 together with the exhaust gas and the like. In this case, since the concentration of the pollutant may affect the concentrator 30, it is necessary to remove the pollutant mixed in the exhaust gas or the like by some method (for example, activated carbon adsorption).

<Fifth embodiment>
FIG. 7: is a conceptual diagram showing the principal part structure of the contaminated earth and sand processing system which concerns on the 5th Embodiment of this invention. Parts similar to those of the above-described embodiment are denoted by the same reference numerals as those of the above-described drawings, and description thereof is omitted.

  This embodiment is a combination of the concept of the fourth embodiment and the third embodiment, and is used as a heating source for earth and sand or additives before supplying the exhaust gas of the engine 27 to the tank 61. This is an example.

  As in the fourth embodiment, the earth or sand to be heated with exhaust gas or the like may be either earth or sand before mixing, or earth or sand during or after mixing with the additive. The case where the earth and sand after mixing with an additive material is heated with exhaust gas etc. is illustrated. That is, in the present embodiment, the heat exchanger 75 is provided in the discharge unit 25 (for example, inside the conveyor belt), and the exhaust pipe 60 is connected to the tank 61 via the heat exchanger 75. The other configuration is the same as that of the third embodiment, and the same effect as that of the above-described embodiment is obtained by dissolving the exhaust gas of the engine 27 in a liquid to concentrate carbon dioxide and react with slaked lime. be able to.

  Further, as in the present embodiment, in the mechanism in which carbon dioxide is dissolved in the liquid in the tank 61 and reacted with slaked lime, the exhaust gas or the like is exchanged with the earth or sand or the additive before being supplied to the tank 61. In addition to being able to apply heat such as exhaust gas to the earth or sand or additive with high efficiency, the amount of carbon dioxide dissolved in the liquid can be increased by lowering the temperature of the exhaust gas or the like. In the reaction between slaked lime and carbon dioxide, the reaction heat absorbed by the liquid decreases with less liquid, and the higher the carbon dioxide concentration in the liquid, the higher the reaction efficiency. It works favorably in heating the earth and sand by mixing the carbon solution with slaked lime.

  Since the solubility of liquid carbon dioxide is higher at low temperatures, the amount of carbon dioxide dissolved in the liquid may decrease if the temperature of the earth and sand is high when the carbon dioxide solution is supplied to the earth and sand. Therefore, when quick lime is included in the additive, avoid the earth or sand before mixing or the earth and sand during or after mixing with the additive as in the present embodiment by heating with exhaust gas or the like. Moreover, the fall of the carbon dioxide dissolution amount in the liquid by heating with exhaust gas etc. can be suppressed, and reaction efficiency can be improved effectively.

It is a conceptual diagram showing the principal part structure of the contaminated earth and sand processing system which concerns on the 1st Embodiment of this invention. It is a schematic block diagram of one structural example of the concentrator with which the contaminated earth and sand treatment system which concerns on the 1st Embodiment of this invention was equipped. It is a schematic block diagram of the other structural example of the concentrator with which the contaminated earth and sand treatment system which concerns on the 1st Embodiment of this invention was equipped. It is a conceptual diagram showing the principal part structure of the contaminated earth-and-sand processing system which concerns on the 2nd Embodiment of this invention. It is a conceptual diagram showing the principal part structure of the contaminated earth-and-sand processing system which concerns on the 3rd Embodiment of this invention. It is a conceptual diagram showing the principal part structure of the contaminated earth-and-sand processing system which concerns on the 4th Embodiment of this invention. It is a conceptual diagram showing the principal part structure of the contaminated earth-and-sand processing system which concerns on the 5th Embodiment of this invention.

Explanation of symbols

1, 1a-c Exhaust pipe line 3 Exhaust gas supply line 4 Exhaust line 5 Merger 8 Exhaust line 11 Exhaust tower 20 Self-propelled soil improvement machine 21 Traveling body 22 Sediment receiving part 23 Additive supply part 24 Mixing part 25 Exhaust part 26 Power unit 30 Concentrator 35 Polymer hollow core membrane 36 Heat exchanger 38 Absorption tower 39 Regeneration tower 50 Reactor 51 Reaction vessel 60 Exhaust line 61 Tank 62 Solution supply lines 71, 72, 75 Heat exchanger

Claims (8)

In a contaminated earth and sand treatment system for purifying earth and sand containing at least one of volatile substances or oils as a contaminant,
A sediment receiving section for receiving the sediment to be treated;
An additive supply unit for supplying an additive containing at least one of slaked lime or quicklime;
A mixing unit for mixing and processing the earth and sand from the earth and sand receiving unit and the additive from the additive supply unit;
A discharge unit for discharging earth and sand from the mixing unit;
A power unit with a built-in engine;
A traveling body that supports the earth and sand receiving unit, the additive supply unit, the mixing unit, the discharge unit, and the power unit;
A concentration means for increasing the carbon dioxide concentration of the exhaust gas from the power unit;
A reaction vessel for reacting earth and sand to which an additive has been added and exhaust gas having a carbon dioxide concentration increased by the concentration means;
A polluted earth and sand treatment system, comprising: an exhaust gas supply pipe for supplying exhaust gas whose carbon dioxide concentration is increased by the concentration means to the reaction vessel.   2. The contaminated sediment treatment system according to claim 1, wherein the concentrating means includes a polymer hollow membrane that separates the exhaust gas into a high-concentration carbon dioxide-containing gas and a low-concentration carbon dioxide-containing gas. The polluted earth and sand treatment system is characterized by increasing the carbon dioxide concentration of exhaust gas by separating it from gas containing low concentration carbon dioxide.   The contaminated earth and sand treatment system according to claim 2, further comprising a heat exchanger for exchanging exhaust gas with earth and sand upstream of the polymer hollow core membrane, and heating the earth and sand to be treated by the heat exchanger. A polluted earth and sand treatment system characterized by cooling exhaust gas supplied to a hollow core membrane. The contaminated sediment treatment system according to claim 1,
The concentration means includes an absorption tower storing a solution that absorbs carbon dioxide in exhaust gas, and a regeneration tower that heats the solution from the absorption tower that absorbs carbon dioxide, and the low-concentration dioxide that has passed through the absorption tower. A polluted earth and sand treatment system characterized in that exhaust gas is separated into a carbon-containing gas and a high-concentration carbon dioxide-containing gas heated in a regeneration tower and desorbed from a solution. In the contaminated earth and sand treatment system in any one of Claims 2-4,
A first exhaust line for passing exhaust from the reaction vessel;
A second exhaust pipe for passing the low-concentration carbon dioxide-containing gas from the concentration means;
A merger in which the first and second exhaust pipes are connected, and the exhaust from the reaction vessel and the low-concentration carbon dioxide-containing gas merge;
A polluted earth and sand treatment system comprising an exhaust tower for discharging the gas mixed in the merger to the atmosphere. In a contaminated earth and sand treatment system for purifying earth and sand containing at least one of volatile substances or oils as a contaminant,
A sediment receiving section for receiving the sediment to be treated;
An additive supply unit for supplying an additive containing at least one of slaked lime or quicklime;
A mixing unit for mixing and processing the earth and sand from the earth and sand receiving unit and the additive from the additive supply unit;
A discharge unit for discharging earth and sand from the mixing unit;
A power unit with a built-in engine;
A traveling body that supports the earth and sand receiving unit, the additive supply unit, the mixing unit, the discharge unit, and the power unit;
An exhaust pipe through which exhaust gas from the power unit flows;
A tank for storing a liquid that dissolves carbon dioxide in the exhaust gas from the exhaust pipe;
A contaminated sediment treatment system comprising a solution supply pipe for supplying carbon dioxide solution from the tank to the sediment.   The contaminated earth and sand treatment system according to any one of claims 1 to 6, wherein the earth or sand before mixing or the earth and sand during or after mixing with the additive is heated by at least one of exhaust heat and exhaust gas of the power unit. Contaminated earth and sand treatment system, further comprising means for In the contaminated earth and sand treatment system in any one of Claims 1-7,
An input heavy machine that inputs the earth and sand to be treated into the earth and sand receiving part;
A polluted earth and sand treatment system, further comprising a pipe for supplying exhaust gas from the power unit of the input heavy machine to the concentrating means.

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