JP2009233630A - Separating method for polluted substance and facility therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for separating and collecting heavy metal from a polluted substance with high efficiency by using a carbon dioxide dissolved fluid in which carbon dioxide is dissolved at a high concentration and that is maintained under a high pressure as a result of development of the carbon gas dissolved fluid manufacturing device that dissolves the carbon gas at high concentration under high pressure. <P>SOLUTION: The method includes a first step for inputting a substance that is polluted by heavy metal in a pressure container 5, supplying the carbon gas dissolved fluid in which the carbon dioxide is dissolved at high concentration and maintained under a high pressure into the pressure container 5, stirring and mixing it with the heavy metal polluted substance, a second step for dehydrating the heavy metal polluted substance, supplying treatment water to a heavy metal treatment tank 6, removing the carbon gas dissolved fluid in the pressure container 5, and ventilating it to air to supply it to the heavy metal treatment tank 6 under the condition in which a predetermined amount of the carbon gas is discharged, and a third step for separating and collecting the heavy metal by the dehydration treatment after adding a heavy metal coagulant in the heavy metal treatment tank 6. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention efficiently separates and recovers heavy metals such as hexavalent chromium, arsenic, cadmium, and boron, and separates and removes volatile organic halides using carbon dioxide-dissolved water maintained at a high concentration and high pressure. The present invention relates to a method and an installation for the method.

  Incineration ash from incineration of coal ash and waste discharged from coal-fired power plants may contain heavy metals that affect the human body, such as hexavalent chromium, arsenic, and boron. It has become a big problem in promoting effective use and improving the efficiency of disposal methods.

  In recent years, toxic heavy metals have been eluted and leached into groundwater at various manufacturing plant sites and adjacent sites, which has become a major environmental problem.

  Although a method for purifying soil contaminated with heavy metals is not yet well established, a method using carbonated water or an acidic solution has recently been proposed as a new purification technology.

  For example, in Patent Document 1 listed below, harmless powder and granular materials such as soil and coal ash containing heavy metals are washed with carbonated water to remove heavy metal ions from the granular materials. Has been proposed (prior art 1).

  In addition, in Patent Document 2 below, an acidic solution is added to a boron-containing substance such as coal ash to obtain a treatment object, and the boron-containing substance and the acidic solution in the treatment object are brought into contact with each other. Boron contained in the boron-containing material is eluted in the acidic solution, and then the treatment object is solid-liquid separated into a treatment liquid from which the boron has been eluted and a treatment solid from which the boron has been separated and removed, The treatment liquid is further separated into solid and liquid, and the solid content is dehydrated and treated as waste. On the other hand, the treatment solid is rinsed with water to remove the acidic solution and boron remaining in the treatment solid. Then, a method for separating and removing boron has been proposed in which the solid content remaining after rinsing is dehydrated (prior art 2).

On the other hand, in addition to heavy metals, soil contamination is also a problem caused by volatile organic halides such as trichlorethylene that have been used for industrial cleaning such as oil removal in factories and the like. A method for purifying the contaminated soil using carbonated water has been proposed. Specifically, in Patent Document 3 below, a carbonate supply well and a pumping well are formed by excavation at intervals in soil contaminated with an organic halide, and carbonated water or carbonate is formed in the carbonate supply well. A method for purifying contaminated soil, comprising a step of liberating organic halides in the soil by injecting gas, while a step of removing the free organic halides by pumping water from the pumping well. When injecting carbon dioxide, water having different concentrations is used as carbonated water. When carbon dioxide is injected, a purification method is proposed in which carbon dioxide is alternately injected at different carbon dioxide supply rates. (Prior Art 3).
JP 2001-47007 A JP 2003-320342 A Japanese Patent No. 3215102

However, the prior arts 1 to 3 have the following problems.
(1) Powders such as soil and coal ash are negatively charged, and incineration ash and coal ash show a high pH, and this tendency becomes stronger. Therefore, in view of the fact that heavy metal ions are strongly bound to the powder and difficult to remove, in the above cited reference 1, by adding carbonated water having a low pH, an environment in which the adsorption power of heavy metal ions is reduced and is easily separated. However, under the circumstance where the technology for dissolving carbon dioxide gas at a high concentration has not been established, there has been a problem that the pH is not lowered significantly by the carbonated water and the efficiency is poor.
(2) In the above cited reference 2, the adsorption power of heavy metal ions is reduced by an acidic solution such as hydrochloric acid, but there remains a problem in terms of safety and environment.
(3) The above cited reference 3 shows an action (so-called rinsing effect) in which the carbonated water is slightly eroded on the sand or the surface of the soil, which is generally formed of minerals. Although liberation is promoted, there has been a problem that under the circumstances where a technique for dissolving carbon dioxide gas at a high concentration has not been established, the liberation promotion effect by carbonated water is low and it is difficult to improve efficiency.

  Accordingly, the main problem of the present invention is that, along with the development of a carbon dioxide-dissolved water production apparatus that dissolves carbon dioxide gas at a high concentration under a high-pressure state, carbon dioxide gas is dissolved at a high concentration and carbon dioxide that is maintained at a high-pressure state. The object is to propose a method and equipment for separating and recovering heavy metals from pollutants with high efficiency using gas-dissolved water and separating and removing volatile organic halides with high efficiency.

In order to solve the above-mentioned problem, as the present invention according to claim 1, a substance contaminated with heavy metal is introduced into a pressure vessel so that carbon dioxide is dissolved at a high concentration and carbon dioxide is dissolved in a high pressure state. Supplying water into the pressure vessel and stirring and mixing with the heavy metal contaminant;
A state in which the heavy metal pollutant is dehydrated and treated water is supplied to the heavy metal treatment tank, and the carbon dioxide-dissolved water in the pressure vessel is extracted and released to atmospheric pressure to release a predetermined amount of carbon dioxide. A second step of supplying the heavy metal treatment tank at
In the heavy metal treatment tank, there is provided a method for separating contaminants, comprising a third step of separating and collecting heavy metal by dehydration after adding a heavy metal flocculant.

  In the first aspect of the invention, carbon dioxide gas is dissolved at a high concentration, and carbon dioxide-dissolved water maintained at a high pressure is supplied into a pressure vessel in which heavy metal contaminants are introduced, and the heavy metal contaminants and Stir and mix. Carbon dioxide-dissolved water obtained by dissolving carbon dioxide in water or salt water at a high concentration (concentration close to saturation solubility) in a high-pressure state (at least about 5.8 MPa in which carbon dioxide is in a liquid state) is shown in FIG. From the literature (Q & A of metal corrosion / corrosion prevention, Petroleum industry edition, Corrosion and corrosion prevention association, Maruzen Publishing Co., Ltd., p10), it is predicted that the pH will be at least about 2-3. As an environment for the purification, an environment in which the adsorption power of heavy metal ions is reduced and separation is facilitated can be made, so that heavy metals can be separated and recovered with high efficiency.

  By the way, in this method, in separating and recovering heavy metals such as hexavalent chromium, arsenic, cadmium and boron, the recovery efficiency of heavy metals can be improved as the pH is lowered. Figure 11 shows the relationship between boron extraction rate and pH based on previous literature (Obayashi Institute of Technology Report No. 68 Development of Boron Removal Technology by Acid Washing of Coal Ash (Part 2)). The lower the pH, the higher the boron extraction rate. Figure 12 shows the relationship between the extraction rate of arsenic and selenium and pH based on past literature (subsidy for scientific research expenses such as the Ministry of the Environment waste processing, etc., next-generation waste processing infrastructure development situation report summary information search results). However, similarly, the lower the pH, the higher the extraction rate of arsenic and selenium. Furthermore, FIG. 13 shows the influence of the presence or absence of carbon dioxide on the recovered amount of hexavalent chromium according to previous literature (35th Geotechnical Research Presentation (Gifu) p.199-200). It can be seen that the recovery rate of hexavalent chromium is improved when carbon dioxide is supplied.

  After mixing heavy metal contaminants and carbon dioxide-dissolved water, dehydrate the heavy metal contaminants, supply the treated water to the heavy metal treatment tank, extract the carbon dioxide-dissolved water in the pressure vessel, and open it to atmospheric pressure By supplying the heavy metal treatment tank with a predetermined amount of carbon dioxide gas released, and adding the heavy metal flocculant in the heavy metal treatment tank, the heavy metal can be efficiently separated and recovered by dehydration treatment. It becomes. Moreover, since the carbon dioxide-dissolved water maintained at a high pressure is released to atmospheric pressure, the amount of carbon dioxide dissolved under atmospheric pressure becomes equivalent, so that the pH can be neutralized and the final treated water is neutralized. Processing is also unnecessary.

As the present invention according to claim 2, a substance contaminated with a volatile organic halide is introduced into a pressure vessel, and the carbon dioxide dissolved water maintained at a high pressure is dissolved in the carbon dioxide at a high concentration. A first step of feeding into a pressure vessel and stirring and mixing with the volatile organic halide contaminant;
The volatile organic halide is dehydrated and treated water is supplied to the volatile organic halide treatment tank, and the carbon dioxide-dissolved water in the pressure vessel is withdrawn and opened to atmospheric pressure to release a predetermined amount of carbonic acid. A second step of supplying gas to the volatile organic halide treatment tank in a released state;
In the volatile organic halide treatment tank, there is provided a method for separating contaminants, comprising a third step of separating and removing volatile organic halides by aeration or adsorption treatment.

  The invention according to claim 2 applies the present invention to volatile organic halide contaminants. FIG. 14 shows the relationship between the detected amount of trichlorethylene in the contaminated soil and the carbonic acid concentration according to the existing literature (Japanese Patent No. 3215102). The higher the carbonic acid concentration, the higher the detected amount of trichlorethylene. I understand. Therefore, according to the present invention, carbon dioxide-dissolved water in which carbon dioxide is dissolved in water or salt water at a high concentration (concentration close to saturation solubility) in a high-pressure state (at least about 5.8 MPa in which carbon dioxide is in a liquid state) is used. This makes it possible to separate and remove volatile organic halides with high efficiency.

  The treatment procedure consists of mixing volatile organic halide contaminants with carbon dioxide dissolved water maintained at a high concentration and high pressure in a pressure vessel, and then dehydrating the volatile organic halide contaminants. While supplying water to the treatment tank, the carbon dioxide-dissolved water in the pressure vessel is withdrawn and released to atmospheric pressure to supply a predetermined amount of carbon dioxide gas to the treatment tank. The volatile organic halide is separated and removed by aeration or adsorption treatment.

As the present invention according to claim 3, a carbon dioxide gas compression device that compresses carbon dioxide gas to a liquid or supercritical state, a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and the compressed carbon dioxide and It is composed of one or a plurality of dissolution tanks in which a solvent is injected and the carbon dioxide gas is dissolved in the solvent to form carbon dioxide-dissolved water. A carbon dioxide gas inlet for injecting carbon dioxide gas sent from and a solvent inlet for injecting a solvent sent from the solvent pressure pump are formed, and the carbon dioxide-dissolved water is formed above the container. A carbon dioxide dissolved water production apparatus configured to form a discharge port to be discharged and filled with a granular filler in the container;
One or a plurality of pressure vessels that are charged with heavy metal contaminants and that are equipped with a stirrer and that are supplied with carbon dioxide gas produced by the carbon dioxide-dissolved water production device maintained in a pressure state;
A first dehydration apparatus for dehydrating heavy metal contaminants taken out of the pressure vessel;
A heavy metal treatment tank to which treated water of the dehydration treatment apparatus is supplied, is extracted from the pressure vessel, is supplied with carbon dioxide-dissolved water that has been released to atmospheric pressure, and is added with a flocculant for heavy metals,
2. The facility for separating contaminants according to claim 1, further comprising a second dehydrating apparatus for dehydrating the object to be processed in the heavy metal processing tank and separating and recovering the heavy metal.

As the present invention according to claim 4, a carbon dioxide compression device that compresses carbon dioxide to a liquid or supercritical state, a pump that compresses and conveys a solvent composed of seawater and / or water, and the compressed carbon dioxide and It is composed of one or a plurality of dissolution tanks in which a solvent is injected and the carbon dioxide gas is dissolved in the solvent to form carbon dioxide-dissolved water. A carbon dioxide gas inlet for injecting carbon dioxide gas sent from and a solvent inlet for injecting a solvent sent from the solvent pressure pump are formed, and the carbon dioxide-dissolved water is formed above the container. A carbon dioxide dissolved water production apparatus configured to form a discharge port to be discharged and filled with a granular filler in the container;
Volatile organic halide contaminants are charged, and equipped with a stirrer, and one or more pressure vessels to which carbon dioxide produced by the carbon dioxide-dissolved water production apparatus is supplied while maintaining a pressure state;
A dehydration apparatus for dehydrating volatile organic halide contaminants removed from the pressure vessel;
The volatile organic halide is separated and removed by aeration or adsorption treatment by supplying the treated water of the dehydration apparatus and the carbon dioxide dissolved water extracted from the pressure vessel and released to atmospheric pressure. The facility for separating contaminants according to claim 2, comprising an organic halide treatment tank.

As the present invention according to claim 5, instead of the carbon dioxide dissolved water production apparatus,
A carbon dioxide gas compressing device that compresses carbon dioxide gas to a liquid or supercritical state, and a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and a main flow line that flows the solvent at a predetermined high flow rate. The carbon dioxide gas supply pipe is disposed inside, or the carbon dioxide gas supply pipe that externally fits the main flow pipe is disposed, and pores are formed in the wall surface of the pipe that partitions the solvent and carbon dioxide. A high-pressure carbon dioxide gas foaming device is formed and mixed while the carbon dioxide gas is made fine by the shearing force of the solvent flowing through the main flow line, and is installed at the subsequent stage of the high-pressure carbon dioxide gas foaming device. In addition, an inlet for the solvent mixed with the fine carbon dioxide gas is formed at the bottom of the sealed container, and an outlet for discharging the carbon dioxide-dissolved water is formed at the top of the container. The container is filled with a granular filler. Equipment for the method of separating contaminants according to any one of claims 3 and 4 using the configured one or more dissolution tank and carbonic gas dissolved water generator consists is provided.

  As described above in detail, according to the present invention, with the development of a carbon dioxide-dissolved water production apparatus that dissolves carbon dioxide at a high concentration under a high pressure state, the carbon dioxide gas is dissolved at a high concentration and maintained at a high pressure state. By using the dissolved carbon dioxide water, heavy metals can be separated and recovered from pollutants with high efficiency, and volatile organic halides can be separated and removed with high efficiency.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
FIG. 1 is a system schematic diagram of a contaminant separation method according to a first embodiment of the present invention. In the first embodiment, heavy metals such as hexavalent chromium, arsenic, cadmium, and boron are efficiently separated and recovered using carbon dioxide-dissolved water maintained at a high concentration and high pressure.

Specifically, as shown in FIG. 1, a substance M contaminated with heavy metal is introduced into the pressure vessel 5 to dissolve carbon dioxide at a high concentration and to dissolve carbon dioxide maintained at a high pressure. A first step of supplying water into the pressure vessel 5 and stirring and mixing with the heavy metal contaminant M;
The heavy metal contaminant M is dehydrated and treated water is supplied to the heavy metal treatment tank 6, and the carbon dioxide-dissolved water in the pressure vessel 5 is extracted and released to atmospheric pressure to release a predetermined amount of carbon dioxide. A second step of supplying the heavy metal treatment tank 6 in a state in which
In the heavy metal treatment tank 6, after adding the heavy metal flocculant, it comprises a third step of separating and recovering heavy metal by dehydration.

  The heavy metal pollutant M targeted in the first embodiment is mainly coal ash discharged from a coal-fired power plant, incineration ash remaining after incineration of industrial waste, soil contaminated by elution of heavy metals, and the like.

  The pressure vessel 5 is a vessel that can sufficiently withstand the pressure of carbon dioxide-dissolved water maintained at a high pressure, specifically, at least about 5.8 MPa in which carbon dioxide is in a liquid state. A stirrer 7 for stirring and mixing is provided. The number of installations is arbitrary according to the processing capacity.

  Carbon dioxide-dissolved water in which carbon dioxide is dissolved at a high pressure in a high-pressure state by a carbon dioxide-dissolved water production apparatus 1 to be described later is supplied to the pressure vessel 5 while maintaining the pressure state. Stir and mix with M.

  The heavy metal contaminant M mixed with the carbon dioxide-dissolved water is naturally settled and then taken out from the pressure vessel 5 and subjected to a dehydration process. As the dehydration processing apparatus 8, a known dehydration apparatus such as a pressure dehydration apparatus such as a filter press, a belt press or a roll press, a vacuum dehydration apparatus such as a belt filter or an oliver filter, a centrifugal dehydration apparatus such as a screw decanter, or the like is used. Can do. In the cake after the dehydration treatment, heavy metals are peeled off from coal ash, incinerated ash, and soil particles, so the heavy metal content is below the standard value.

  The dehydrated water is then supplied to the heavy metal treatment tank 6, and the carbon dioxide-dissolved water is extracted from the pressure vessel 5. After the pressure is brought to atmospheric pressure by opening to the atmosphere, the water is supplied to the heavy metal treatment tank 6. The In addition, as shown in the drawing, the carbon dioxide released to the atmosphere is preferably returned to the carbon dioxide-dissolved water production apparatus 1 for reuse.

  In the heavy metal treatment tank 6, a heavy metal flocculant is added, and the heavy metal forms flocs and settles and separates. As the heavy metal flocculant, known ones such as a flocculant composed of a water-soluble polymer and a polyvalent metal ion, a γ-polyglutamic acid crosslinked body, and a heavy metal flocculant containing bentonite can be used. The sedimented and separated heavy metal floc is separated and recovered by dehydration, and the treated water can be discharged as it is without neutralization because carbon dioxide has already been released into the atmosphere.

[Second embodiment]
Next, the pollutant separation method according to the second embodiment shown in FIG. 2 efficiently separates volatile organic halides such as trichlorethylene using carbon dioxide-dissolved water maintained at a high concentration and high pressure. To be removed.

Specifically, as shown in FIG. 2, the substance N contaminated with the volatile organic halide is introduced into the pressure vessel 5, so that the carbon dioxide gas is dissolved at a high concentration and maintained at a high pressure state. A first step of supplying the carbon dioxide-dissolved water into the pressure vessel 5 and stirring and mixing with the volatile organic halide contaminant;
The volatile organic halide is dehydrated and treated water is supplied to the volatile organic halide treatment tank, and the carbon dioxide-dissolved water in the pressure vessel 5 is withdrawn and released to atmospheric pressure to achieve a predetermined amount. A second step of supplying carbon dioxide gas to the volatile organic halide treatment tank 9 in a released state;
The volatile organic halide treatment tank 9 comprises a third step of separating and removing volatile organic halides by aeration or adsorption treatment.

  The target volatile organic halide pollutant N in the second embodiment is soil contaminated with volatile organic halides such as trichlorethylene discharged mainly from factories and the like.

  Compared with the first embodiment, only the processing in the processing tank 9 is different and the other processing is the same. Therefore, the description is omitted and the processing in the processing tank 9 will be described.

  Volatile organic halides are separated and removed from the dehydrated treated water and carbon dioxide-dissolved water supplied to the treatment tank 9 by aeration or adsorption treatment. The aeration treatment promotes volatilization of the organic halide, but takes time. Therefore, it is preferable to forcibly perform adsorption treatment using activated carbon.

[About CO2 dissolved water production equipment]
The carbon dioxide dissolved water production apparatus 1 used in this method will be described in detail with reference to FIGS.

<< The carbon dioxide dissolved water manufacturing apparatus 1 which concerns on a 1st form >>
The carbon dioxide-dissolved water production apparatus 1 according to the present invention is for supplying the pressure vessel 5 in a state of being dissolved in a solvent (seawater or water) at a high concentration near the saturation concentration level. Specifically, the amount of carbon dioxide dissolved is targeted to be 80%, preferably 90% or more of the saturation solubility under a predetermined pressure.

  The pressure in the system is such that the carbon dioxide is dissolved in a liquid or supercritical state, and the injection pressure for injecting the carbon dioxide-dissolved water into the pressure vessel 5 and the pressure in the piping system are used. Considering the loss, a high pressure state of 6 MPa or more is maintained.

  As shown in FIG. 3, the carbon dioxide-dissolved water production apparatus 1 includes a carbon dioxide compressor 2 that compresses carbon dioxide to a liquid or supercritical state, and a pump that compresses and conveys a solvent composed of seawater and / or water. 3 and a plurality of dissolution tanks 4, 4... Into which the compressed carbon dioxide gas and solvent are injected and the carbon dioxide gas is dissolved in the solvent to form carbon dioxide-dissolved water. A plurality of the dissolution tanks 4 are installed in order to promote the dissolution of carbon dioxide gas, but may be one if necessary.

  As shown in FIG. 4, the dissolution tank 4 includes a carbon dioxide gas inlet 11 into which a carbon dioxide gas sent from the carbon dioxide gas compression device 2 is injected into a lower portion of a sealed container 10, and the solvent pressure pump. 3 is formed, and a discharge port 13 for discharging the carbon dioxide-dissolved water is formed in the upper portion of the container 10. The perforated plates 14 and 14 partitioning the inside of the container 10 in the vertical direction are respectively arranged on the upper side, and a granular filler 16 is filled between the perforated plates 14 and 14.

  The filler 16 is for accelerating the stirring of the solvent and the carbon dioxide gas and improving the efficiency of the dissolution of the carbon dioxide gas. For example, the filler 16 may be any one or a combination of sand, crushed stone, Raschig ring, and saddle. it can. The Raschig ring is a cylinder-shaped packing made of ceramic, plastic, metal, carbon, etc., which is used in packed towers and can be used in general. The saddle is a horseshoe-shaped packing made of ceramic or the like, and is generally formed so that the pressure loss is smaller than that of the Raschig ring.

Moreover, the said filler 16 is the optimal average determined from the amount of carbon dioxide dissolution determined based on the flow volume of a carbon dioxide gas and a solvent, and the shape of the said dissolution tank, and the pressure loss in the said dissolution tank for every kind of filler. It is preferable to use a particle size. Specifically, for each type of filler, after experimentally obtaining the following two relationships with respect to the average particle diameter of the filler, the pressure loss allowed in the dissolution tank (inlet and outlet of the dissolution tank) For the difference in pressure between the two, an average particle size with the largest amount of dissolution is selected as the optimum average particle size.
(1) The relationship of the amount of carbon dioxide dissolved with respect to the average particle diameter of the filler in the predetermined flow rate of carbon dioxide gas and solvent and the shape of the dissolution tank.
(2) Relationship between dissolution tank pressure loss and average filler particle size.

  Generally, the properties of the filler with respect to the average particle size are as follows: (1) Given the flow rate of carbon dioxide gas and solvent and the shape of the dissolution tank, the smaller the average particle size of the filler, the more the dissolved amount of carbon dioxide gas. To increase. (2) On the other hand, as the average particle size of the filler becomes finer, the pressure loss due to the flow of carbon dioxide and solvent in the dissolution tank increases, and the energy used to secure a constant flow rate tends to increase. There is. Therefore, the average particle size of the filler is selected after comprehensively considering the flow rates of the carbon dioxide gas and the solvent and the shape of the dissolution tank. In addition, when the required amount of carbon dioxide dissolution cannot be determined, it is also considered to take measures such as increasing the size of the dissolution tank.

  By using the filler 16 having the optimum average particle diameter, the carbon dioxide gas is efficiently dissolved.

  As shown in FIG. 4, the container 10 is preferably a sealed vertically long tube. Thereby, it becomes possible to ensure the residence time of the carbon dioxide gas and the solvent in the dissolution tank 4. Although the residence time depends on the flow rate, when the flow rate is 10 ml / min to 20 ml / min, the residence time is preferably about 20 to 40 minutes. Moreover, it can be set as the structure which has pressure | voltage resistance with respect to the said setting pressure in a system, and the production | generation of a carbon dioxide dissolved water can be continuously and stably in a short time.

  Here, the flow in the dissolution tank 4 will be described with reference to FIG. 4. The carbon dioxide gas and the solvent pumped into the container 10 from the carbon dioxide inlet 11 and the solvent inlet 12 are mixed in the lower hopper 17. And enters the filling region of the filler 16 from the lower perforated plate 14 evenly. In the filling region of the filler 16, the solvent and carbon dioxide are sufficiently stirred together with the flow between the fillers 16 to dissolve the carbon dioxide in the solvent and flow upward. By this action, when the upper porous plate 14 is reached, carbon dioxide-dissolved water in which carbon dioxide is substantially dissolved in the solvent is generated, and reaches the saturated dissolution level of the solvent. Thereafter, the carbon dioxide-dissolved water that has entered the upper hopper 18 from the upper porous plate 14 is discharged from the discharge port 13.

  In the dissolution tank 4, it is desirable to provide one or a plurality of rectifying plates 19 in which a large number of openings are formed so as to partition the flow path in the filling region of the filler 16. By providing the rectifying plate 19, the flow of the carbon dioxide gas and the solvent by the filler 16 is made uniform, and the dissolution of the carbon dioxide gas in the dissolution tank 4 is improved by increasing the chance of contact between them. The residence time in the dissolution tank 4 and the carbon dioxide gas dissolution amount are in a generally proportional relationship up to the saturation concentration level. Therefore, the apparatus scale is set so that the residence time according to the target dissolution amount is obtained under predetermined operating conditions. It is desirable to set.

  Each flow rate of the solvent and carbon dioxide gas per dissolution tank is the weight of the injected carbon dioxide gas and solvent with respect to the total flow rate determined by the volume of the dissolution tank 4 and the residence time of the carbon dioxide gas and solvent in the dissolution tank 4. It can be determined from the ratio (carbon dioxide weight / solvent weight). At this time, the weight ratio between the carbon dioxide gas and the solvent is determined based on the desired amount of carbon dioxide dissolved. The relationship between the weight ratio of the carbon dioxide gas and the solvent and the dissolved amount of the carbon dioxide gas is determined by a water flow test performed in advance.

  As will be described in detail in the following examples, the dissolution concentration in the dissolution tank 4 affects the weight ratio of the injected carbon dioxide gas to the solvent (carbon dioxide weight / solvent weight). Specifically, as the weight ratio to be injected increases, the dissolution concentration in the dissolution tank 4 tends to increase. For the purpose of promoting the dissolution of carbon dioxide, the injection weight ratio of carbon dioxide and solvent is: It is preferable to set it larger than the target value of the carbon dioxide gas dissolution concentration.

<< 1A of carbon dioxide dissolved water manufacturing apparatus which concerns on 2nd form >>
Next, in comparison with the first embodiment, the carbon dioxide dissolved water production apparatus 1A according to the second embodiment shown in FIG. Simply called a fine foaming device).

  The fine foaming device 7A shown in FIG. 6 uses a seawater and / or water as a solvent, and a carbon dioxide gas supply pipe that externally fits the mainstream pipe 30 in which these solvents are flowed at a predetermined high flow rate. 31 is formed in the wall surface of the pipe line for partitioning the solvent and carbon dioxide gas, in the illustrated example, the pipe wall face of the main flow pipe line 30, and the pores 30 a, 30 a. The carbon dioxide gas compressed to a liquid or supercritical state is mixed while being made into a fine bubble by the shearing force.

  When a plurality of the pores 30a are arranged, as shown in the figure, it is desirable that the pores 30a are arranged on the wall surface of the mainstream pipe 30 in a uniform manner in the circumferential direction and in a multistage arrangement with an interval in the axial direction. .

The flow rate of the solvent and the pore diameter of the pores 30a are preferably set so that the Weber number (We) obtained by the following formula (1) is 10 or more according to Example 2-3 described later. However, the flow rate of the carbon dioxide gas from the pore is required to be 8 × 10 ⁻² m / s or more.

なお、前記細泡化された炭酸ガスの径は、概ね０．０５〜０．２mm程度で十分であり、特にマイクロレベル（１０〜数十μｍ）までは細泡化する必要はない。

The diameter of the fine carbon dioxide gas is about 0.05 to 0.2 mm, and it is not necessary to make it fine up to the micro level (10 to several tens of μm).

  7 and FIG. 8 are provided with a carbon dioxide gas supply line 31 inside a main flow line 30 in which a solvent is allowed to flow at a predetermined high flow rate. .. Are formed in the pipe wall surface for partitioning carbon dioxide gas, in the illustrated example, the pipe wall surface of the carbon dioxide gas supply pipe 31, and the liquid or superfluous is formed by the shear force of the solvent flowing through the main flow pipe 30. Carbon dioxide gas compressed to a critical state is mixed while being made fine.

  As shown in FIG. 5, the carbon dioxide-dissolved water production apparatus 1A includes a carbon dioxide compression apparatus 2 that compresses carbon dioxide to a liquid or supercritical state, and a pump that compresses and conveys a solvent composed of seawater and / or water. 3 and the fine foaming devices 7, 7... For making the liquid or the carbon dioxide gas compressed to the supercritical state into fine bubbles and mixing them in the solvent, and the fine foaming devices 7, 7. A solvent in which carbon dioxide gas is mixed is injected, and is mainly composed of a plurality of dissolution tanks 4A, 4A,.

  As shown in FIG. 9, the fine foaming device 7 is installed at the lower part of each dissolution tank 4, and a carbon dioxide gas supply line 31 is provided inside a main flow line 30 in which a solvent is flowed at a predetermined high flow rate. Are formed in the wall surface of the carbon dioxide gas supply line 31 that partitions and separates the solvent and the carbon dioxide gas, and is in a liquid or supercritical state by the shearing force of the solvent flowing through the main flow line 30. A fine foaming device 7 is used for mixing carbon dioxide gas compressed to a fine foam.

  As shown in FIG. 9, the dissolution tank 4 </ b> A has an inlet 9 through which a solvent mixed with carbon dioxide gas that has been made fine by the fine foaming device 7 is injected into the lower part of a sealed container 10. And a discharge port 13 through which the carbon dioxide-dissolved water is discharged is formed in the upper part of the container 10, and a porous partitioning the inside of the container 10 vertically in the lower and upper parts of the container 10, respectively. Plates 14 and 14 are arranged, respectively, and a granular filler 16 is filled between the porous plates 14 and 14. A mesh plate 15 is installed at the inlet 9.

  Here, the flow in the dissolution tank 4 will be described. The carbon dioxide gas and the solvent pumped into the container 10 from the injection port 9 enter the filling region of the filler 16 evenly from the mesh plate 15. In the filling region of the filler 16, the solvent and carbon dioxide are sufficiently stirred together with the flow between the fillers 16 to dissolve the carbon dioxide in the solvent and flow upward. By this action, when the upper porous plate 14 is reached, carbon dioxide-dissolved water in which carbon dioxide is substantially dissolved in the solvent is generated, and reaches the saturated dissolution level of the solvent. Thereafter, the carbon dioxide-dissolved water that has entered the upper hopper 18 from the upper porous plate 14 is discharged from the discharge port 13.

  In the dissolution tank 4, it is desirable to provide one or a plurality of rectifying plates 19 in which a large number of openings are formed so as to partition the flow path in the filling region of the filler 16. By providing the rectifying plate 19, the flow of the carbon dioxide gas and the solvent by the filler 16 is made uniform, and the dissolution of the carbon dioxide gas in the dissolution tank 4 is improved by increasing the chance of contact between them. The residence time in the dissolution tank 4 and the carbon dioxide gas dissolution amount are in a generally proportional relationship up to the saturation concentration level. Therefore, the apparatus scale is set so that the residence time according to the target dissolution amount is obtained under predetermined operating conditions. It is desirable to set.

[Other examples]
(1) In the first embodiment and the second embodiment, heavy metal contaminants and volatile organic halide contaminants are targeted. However, as shown in FIG. 15, the method of the present invention neutralizes alkaline waste liquid. Therefore, it is also possible to use carbon dioxide-dissolved water produced by a carbon dioxide-dissolved water production apparatus.

  In order to verify the dissolution state of carbon dioxide gas by the carbon dioxide-dissolved water production apparatus 1, a carbon dioxide dissolution experiment was performed using the experimental apparatus shown in FIG. In addition, the fine foaming apparatus 7 was installed in the case with the fine foaming apparatus of Example 2 mentioned later.

  The experimental apparatus pressurizes the carbon dioxide in the carbon dioxide cylinder 30 by the carbon dioxide compressor 2 and injects it into the dissolution tank 4, and pressurizes the salt water in the salt water tank 31 by the solvent pump 3 and injects it into the dissolution tank 4 for dissolution. Carbon dioxide dissolved in the tank 4 is sampled, and the carbon dioxide dissolved water after the carbon dioxide dissolved water is separated from the undissolved carbon dioxide in the separation tank is sampled. Here, the volume of the dissolution tank 4 was 850 ml, and the filler 16 used was a sand-like material having an average particle size of 0.18 mm (particle size 1), 0.63 mm (particle size 2), and 1.32 mm (particle size 3). In the experiment, when the temperature, pressure, salt water flow rate, particle size of the filler 16 and the weight ratio of carbon dioxide and salt water (carbon dioxide weight / salt water weight) were changed, the amount of carbon dioxide dissolved in the sampled carbon dioxide dissolved water was changed. It was measured.

  17 and 18 show the weight ratio of carbon dioxide and salt water (carbon dioxide weight / salt water weight) and carbon dioxide dissolution when injected into the dissolution tank 4 when the flow rate of salt water at each temperature and the particle size of the filler 16 are changed. It is a graph which shows the relationship with quantity. As a result, at any of the test temperatures of 29 ° C. and 33 ° C., the amount of carbon dioxide dissolved tends to increase as the weight ratio of carbon dioxide to salt water increases and the particle size of the filler 16 decreases.

  19 to 21 are graphs showing the relationship between the weight ratio and the amount of dissolved carbon dioxide gas when the brine flow rate and pressure at each temperature are changed. As a result, as described above, as the weight ratio of carbon dioxide and salt water increases, the amount of dissolved carbon dioxide tends to increase, but at a certain weight ratio or more, the amount of dissolved carbon dioxide becomes a substantially constant saturation concentration level, The effectiveness of the carbon dioxide dissolved water production apparatus 1 was confirmed.

  FIG. 22 is a graph showing the relationship between the temperature at each pressure and the amount of carbon dioxide dissolved. As a result, it was confirmed that, under general temperature conditions in the range of 25 ° C. to 40 ° C., the carbon dioxide dissolution amount was not greatly affected.

  FIG. 23 is a graph comparing the difference in the amount of carbon dioxide dissolved between salt water and water. In the test, the amount of carbon dioxide dissolved in each case of salt water and water was compared for two cases with different flow rates. From the figure, it was found that the solubility of carbon dioxide gas was higher by about 25 to 33% when water was used.

  FIG. 24 is a graph showing the relationship between the average particle diameter of the filler and the amount of carbon dioxide dissolved at each brine flow rate. As a result, in this example, the average particle size of the filler is excellent in the dissolution efficiency of carbon dioxide gas by setting the average particle size to 1.0 mm or less.

(Example 2-1)
In the present Example 2-1, an experiment for quantitatively verifying the dissolution effect in the fine foaming device 7 and the dissolution effect in the dissolution tank 4 by the carbon dioxide dissolved water production device 1 was performed.

  Experiments were: Case 1: No filler in dissolution tank 4 and no fine foaming device 7, Case 2: No filler in dissolution tank 4 and fine foaming device 7, Case 3: With filler in dissolution tank 4 and (1) Test pressure: 15 MPa, test temperature: 29 ° C., (carbon dioxide / brine water) weight ratio: about 8%, (2) Test pressure: 15 MPa, test temperature: 33 A dissolution test was conducted on two types of C, and (carbon dioxide / salt water) weight ratio: about 8%.

  The result is shown in FIG. From FIG. 25, the dissolution of carbon dioxide gas is considerably promoted by the fine foaming device 7 alone, and further, the dissolution is further promoted by combining the fine foaming device 7 and the dissolution tank 4. I was able to prove.

(Example 2-2)
In the present Example 2-2, verification experiment of the melt | dissolution promotion effect by the said bubble reduction apparatus 7 was conducted.

  In general, it has been found that the relationship of the following equation (2) holds between the amount of carbon dioxide dissolved and the container height Z of the dissolution tank.

The height Z of the container required for dissolution is dependent on overall capacity coefficient K _{X a,} and the overall capacity coefficient K _{X a} as an index representing the dissolution efficiency. The experiment is for each case without a foaming device and with a foaming device. (1) Test pressure: 15 MPa, Test temperature: 29 ° C, (Carbon dioxide / salt water) Weight ratio: About 8%, (2) Test Pressure: 15 MPa, test temperature: 29 ° C., (carbon dioxide / salt water) weight ratio: about 10%, (3) test pressure: 15 MPa, test temperature: 33 ° C., (carbon dioxide / salt water) weight ratio: about 8% As shown in FIGS. 26 to 28, three types of tests were conducted, and as shown in FIGS. 26 to 28, the vertical axis represents the overall capacity coefficient K _x a (mol / m ³ s), and the horizontal axis represents the cross-sectional molar flow velocity of water (mol / (m ²・ The graph of s)) was obtained. According to the graphs of FIGS. 26 to 28, in the region where the cross-sectional molar flow velocity (mol / (m ² · s)) of water is high, the case with the foaming device is compared with the case without the foaming device. Thus, it has been found that the overall capacity coefficient K _x a is 1.5 times or more.

(Example 2-3)
The experimental results of Example 2-2 were rearranged using the Weber number We shown in the following formula (1), and as shown in FIG. 29, the vertical axis represents the overall capacity coefficient ratio K _x a (B) / K _x a (NB) [where K _x a (B): overall capacity coefficient with a finer, K _x a (NB): overall capacity without a finer], the horizontal axis is the Weber coefficient A graph of We was obtained.

From the figure, it was found that the dissolution efficiency by fine foaming is high in the region where the Weber number We is 10 or more. Therefore, in the fine foaming device 7, the solvent flow rate and the pore diameter of the pores 30a (31a) are preferably set so that the Weber number (We) is 10 or more. However, according to the same experiment, the flow rate of carbon dioxide from the pores is 8 × 10 ⁻² m / s or more.

It is a system schematic diagram of the separation method of contaminant concerning the 1st example of the present invention. It is the system schematic of the separation method of the contaminant which concerns on the 2nd form example of this invention. It is the schematic which shows the carbon dioxide dissolved water manufacturing apparatus. 2 is a longitudinal sectional view showing a dissolution tank 4. FIG. It is the schematic which shows the carbon dioxide dissolved water manufacturing apparatus 1A. It is a longitudinal cross-sectional view of 7 A of fine foaming apparatuses. It is a longitudinal cross-sectional view of the fine foaming apparatus 7B. It is a longitudinal cross-sectional view of 7 C of fine bubble apparatuses. It is a longitudinal cross-sectional view of the dissolution tank 4A. Is a graph showing the relationship between the CO ² partial pressure and the temperature · pH of Nacl aqueous solution by previous literature. It is a graph which shows the relationship between the boron extraction rate by past literature, and pH. It is a graph which shows the relationship between arsenic / selenium extraction rate and pH by past literature. It is a graph which shows the influence which the washing | cleaning method by past literature has on the collection amount of hexavalent chromium. It is a graph which shows the relationship between the amount of trichlorethylene detection by previous literature, and carbonated water concentration. It is the schematic which showed the utilization method of the high concentration carbon dioxide dissolved water based on another form example. It is a conceptual diagram of an experimental apparatus. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the particle size and salt water flow rate in the temperature of 29 degreeC in Example 1, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the particle size and salt water flow rate in the temperature of 33 degreeC in Example 1, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the pressure in 25 degreeC in Example 1, and the flow rate of salt water, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio and the amount of carbon dioxide dissolved when the pressure at a temperature of 29 ° C. and the salt water flow rate in Example 1 are changed. It is a graph which shows the relationship between the carbon dioxide gas / salt water weight ratio when changing the conditions of the pressure in 33 degreeC in Example 1, and the flow rate of salt water, and a carbon dioxide dissolved amount. It is a graph which shows the relationship between the temperature in Example 1, and a carbon dioxide gas dissolution amount. 3 is a graph showing the relationship between the salt water / water weight ratio and the amount of carbon dioxide dissolved in Example 1. FIG. 2 is a graph showing the relationship between the average particle diameter of fillers in Example 1 and the amount of carbon dioxide dissolved. It is a graph which shows a verification experiment result quantitatively about the melt | dissolution effect in the fine foaming apparatus 7 in Example 2-1, and the melt | dissolution effect in the melt | dissolution tank 4. Graph showing the relationship between the overall capacity coefficient K _{X a} water cross section molar flow rate in Example 2-2; FIG. Is a graph (part 2) showing the relationship between overall capacity coefficient K _{X a} water cross section molar flow rate in Example 2-2. Graph showing the relationship between the overall capacity coefficient K _{X a} water cross section molar flow rate in Example 2-2 is a third. Is a graph showing the relationship between the overall capacity coefficient ratio _{K x a (B) / K} x a (NB) and Weber number We in Example 2-3.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Carbon dioxide dissolved water manufacturing apparatus, 2 ... Carbon dioxide compression apparatus, 3 ... Solvent pressure feed pump, 4 * 4A ... Dissolution tank, 5 ... Pressure vessel, 6 ... Heavy metal processing tank, 7 ... Fine foaming apparatus, 8 ... Dehydration Device: 10 ... Container, 11 ... Carbon dioxide gas inlet, 12 ... Solvent inlet, 13 ... Discharge port, 14 ... Perforated plate, 15 ... Mesh plate, 16 ... Filler, 19 ... Rectifier plate, 30 ... Main flow line, 31 ... Carbon dioxide gas supply line, 30a / 31a ... Fine pore

Claims (5)

A substance contaminated with heavy metal is introduced into the pressure vessel, carbon dioxide gas is dissolved at a high concentration, and carbon dioxide-dissolved water maintained at a high pressure is supplied into the pressure vessel, and the heavy metal contaminant is stirred. A first step of mixing;
A state in which the heavy metal pollutant is dehydrated and treated water is supplied to the heavy metal treatment tank, and the carbon dioxide-dissolved water in the pressure vessel is extracted and released to atmospheric pressure to release a predetermined amount of carbon dioxide. A second step of supplying the heavy metal treatment tank at
In the heavy metal treatment tank, the third step of separating and recovering heavy metal by dehydration after adding a heavy metal flocculant is provided. A substance contaminated with volatile organic halide is introduced into the pressure vessel, and carbon dioxide gas is dissolved at a high concentration. Carbon dioxide-dissolved water maintained at a high pressure is supplied into the pressure vessel, and the volatilization is performed. A first step of stirring and mixing with the volatile organic halide contaminant;
The volatile organic halide is dehydrated and treated water is supplied to the volatile organic halide treatment tank, and the carbon dioxide-dissolved water in the pressure vessel is withdrawn and opened to atmospheric pressure to release a predetermined amount of carbonic acid. A second step of supplying gas to the volatile organic halide treatment tank in a released state;
A method for separating contaminants, comprising a third step of separating and removing volatile organic halides by aeration or adsorption treatment in the volatile organic halide treatment tank. A carbon dioxide gas compression device that compresses carbon dioxide gas to a liquid or supercritical state, a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and the compressed carbon dioxide gas and solvent are injected, and the solvent is It is composed of one or a plurality of dissolution tanks that dissolve carbon dioxide to form carbon dioxide-dissolved water, and the dissolution tank is injected with the carbon dioxide gas sent from the carbon dioxide compression device at the bottom of a sealed container. A carbon dioxide gas injection port and a solvent injection port into which the solvent sent from the solvent pressure pump is injected, and a discharge port through which the carbon dioxide dissolved water is discharged at the top of the container are formed, A carbon dioxide-dissolved water production apparatus configured by filling the container with a granular filler;
One or a plurality of pressure vessels that are charged with heavy metal contaminants and that are equipped with a stirrer and that are supplied with carbon dioxide gas produced by the carbon dioxide-dissolved water production device maintained in a pressure state;
A first dehydration apparatus for dehydrating heavy metal contaminants taken out of the pressure vessel;
A heavy metal treatment tank to which treated water of the dehydration treatment apparatus is supplied, is extracted from the pressure vessel, is supplied with carbon dioxide-dissolved water that has been released to atmospheric pressure, and is added with a flocculant for heavy metals,
2. The facility for separating contaminants according to claim 1, further comprising a second dehydrating apparatus for dehydrating the object to be processed in the heavy metal processing tank and separating and collecting the heavy metal. A carbon dioxide gas compression device that compresses carbon dioxide gas to a liquid or supercritical state, a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and the compressed carbon dioxide gas and solvent are injected, and the solvent is It is composed of one or a plurality of dissolution tanks that dissolve carbon dioxide to form carbon dioxide-dissolved water, and the dissolution tank is injected with the carbon dioxide gas sent from the carbon dioxide compression device at the bottom of a sealed container. A carbon dioxide gas injection port and a solvent injection port into which the solvent sent from the solvent pressure pump is injected, and a discharge port through which the carbon dioxide dissolved water is discharged at the top of the container are formed, A carbon dioxide-dissolved water production apparatus configured by filling the container with a granular filler;
Volatile organic halide contaminants are charged, and equipped with a stirrer, and one or more pressure vessels to which carbon dioxide produced by the carbon dioxide-dissolved water production apparatus is supplied while maintaining a pressure state;
A dehydration apparatus for dehydrating volatile organic halide contaminants removed from the pressure vessel;
The volatile organic halide is separated and removed by aeration or adsorption treatment by supplying the treated water of the dehydration apparatus and the carbon dioxide dissolved water extracted from the pressure vessel and released to atmospheric pressure. 3. The facility for separating contaminants according to claim 2, comprising an organic halide treatment tank. Instead of the carbon dioxide dissolved water production device,
A carbon dioxide gas compressing device that compresses carbon dioxide gas to a liquid or supercritical state, and a pressure feed pump that compresses and conveys a solvent composed of seawater and / or water, and a main flow line that flows the solvent at a predetermined high flow rate. The carbon dioxide gas supply pipe is disposed inside, or the carbon dioxide gas supply pipe that externally fits the main flow pipe is disposed, and pores are formed in the wall surface of the pipe that partitions the solvent and carbon dioxide. A high-pressure carbon dioxide gas foaming device is formed and mixed while the carbon dioxide gas is made fine by the shearing force of the solvent flowing through the main flow line, and is installed at the subsequent stage of the high-pressure carbon dioxide gas foaming device. In addition, an inlet for the solvent mixed with the fine carbon dioxide gas is formed at the bottom of the sealed container, and an outlet for discharging the carbon dioxide-dissolved water is formed at the top of the container. The container is filled with a granular filler. Equipment for the method of separating contaminants according to any one of claims 3 and 4 using the configured one or more dissolution tank and carbonic gas dissolved water generator consists.

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