JP2008029967A - Method and apparatus for treating contaminants - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating contaminants capable of reducing an initial cost of facilities that detoxify contaminants containing undegradable hazardous organic compounds such as dioxins with a supercritical water oxidation decomposition process and improving decomposition efficiency. <P>SOLUTION: A step for extracting the hazardous organic compounds from the contaminants with supercritical carbon dioxide as an extracting solvent and adsorbs the hazardous organic compounds in the supercritical carbon dioxide with an adsorbent with an activated carbon adsorbing tank 2 as a reactor for condensation and decomposition processing, and a step oxidatively decomposing the hazardous organic compounds adsorbed in the adsorbent with the supercritical water are executed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pollutant treatment method and a treatment apparatus for detoxifying a pollutant containing a hardly decomposable harmful organic compound such as dioxins such as municipal waste incineration ash.

  As a conventional processing method for detoxifying the pollutant, an ash melting method in which the pollutant is melted into slag at a high temperature and a Hagenmeier method in which heat treatment is performed at about 400 ° C. in a reducing atmosphere are generally used.

  As a conventional technique for detoxifying a harmful organic compound such as dioxins by a melting method, for example, one disclosed in Patent Document 1 has been proposed. In the treatment method of Patent Document 1, first, harmful organic compounds such as dioxins in waste are thermally decomposed at about 500 to 600 ° C., and the pyrolysis product contains an incombustible material mainly composed of carbon. Separate the char mixture. Then, water is added to the char mixture to form a slurry, and the solid component of the harmful organic compound is solid-liquid separated from the slurry. The solid component thus obtained is rendered harmless by using it as a fuel for a melting furnace for melting an inorganic substance.

  Patent Document 2 discloses a detoxification treatment method for waste containing harmful organic compounds such as dioxins. In this treatment method, waste containing high-concentration dioxins is charged into an incineration facility that burns in an atmosphere of 1200 ° C. or higher to form molten slag. At this time, the exhaust gas containing dioxins generated in the incineration facility is brought into gas-liquid contact with the hydrochloric acid acidic absorbent having a pH in the range of 2.0 to 6.0, and washed with smoke. As a result, the fly ash is transferred into the absorption liquid and the fly ash is stabilized. The absorbent containing the stabilized fly ash contains the reaction catalyst in a dissolved state, and is maintained at a temperature lower than 100 ° C. within a pH range of 2.0 to 6.0, thereby dioxins in the fly ash. To make it harmless.

  Patent Document 3 discloses an ash heating dechlorination apparatus that thermally decomposes dioxins in the ash to be treated. In this device, ash to be treated is placed in a heating tube rotating in a cylindrical or square heating section, and heated by a plurality of heating units provided in the axial direction of the heating tube to thermally decompose dioxins in the ash to be treated. To do. In this heat treatment, the apparatus according to Patent Document 3 makes the heating capacity on the inlet side of the heating pipe larger than that on the outlet side, and controls the heating unit on the inlet side based on the inlet side temperature of the heating unit. The heating unit is controlled based on the temperature of the dechlorinated ash on the outlet side. By doing in this way, dioxins can be efficiently thermally decomposed, preventing the high temperature corrosion of a heating pipe.

  Further, as a processing method for detoxifying dioxins using supercritical water, there is one disclosed in Patent Document 4. In this method, inorganic powder containing dioxins is dispersed in supercritical water that is maintained at a critical temperature or higher and a critical pressure or higher, and supercritical water to which an oxidizing agent is added, and in this state, the dioxins in the inorganic powder are decomposed. Let it harmless.

  Further, Patent Document 5 discloses a plant that decomposes dioxins contained in exhaust gas such as a garbage incineration plant using supercritical water. In this plant, an organic or inorganic solid treatment target adsorbed with dioxins contained in exhaust gas is hydrothermally reacted in a supercritical atmosphere, and organic compounds such as dioxins are dissolved in supercritical water. The reaction product is separated into an inorganic component, a liquid component, and a gas component by a separator, thereby completely detoxifying dioxins.

  In addition, Patent Document 6 discloses a decomposition processing apparatus that decomposes PCB (polychlorinated biphenyl), which is a hardly decomposable chemical substance, as well as dioxins, and renders them harmless. This device is obtained by subjecting a non-metallic member (for example, paper, wood, plastic, etc.) contaminated with PCB to coarse pulverization, and slurrying the resulting slurry to supercritical hydrolytic decomposition. The PCB in the slurry is decomposed and rendered harmless.

Japanese Patent Laid-Open No. 11-125410 JP 2000-274622 A JP 2002-263605 A Japanese Patent Laid-Open No. 9-327678 JP-A-11-290820 JP 2001-327943 A

  In the conventional ash melting method, pollutants are melted into slag at a high temperature of about 1500 ° C., so that energy consumption is large and maintenance of the processing equipment is expensive (for example, Patent Documents 1 and 2). On the other hand, the Hagenmeier method can be processed at a lower temperature than the melting method, but the decomposition rate of dioxins is as low as about 95%.

  Moreover, the direct decomposition of dioxins by supercritical water oxidation as disclosed in Patent Documents 3 to 6 has been attracting attention as a technique that prevents resynthesis of dioxins and that provides a safe and high decomposition rate. . However, in order to perform supercritical hydrolytic decomposition treatment, a container that can create a high-temperature and high-pressure environment is required. For this reason, when the purpose is to decompose dioxins in a large amount of waste such as incineration ash, a large-sized high-pressure vessel is required, and it is difficult to say that the practical use is progressing because the initial cost of the equipment is high. .

  The present invention has been made to solve the above-mentioned problems, and reduces the initial cost of equipment for detoxifying pollutants containing hardly decomposable harmful organic compounds such as dioxins by supercritical hydroxylation. It is an object of the present invention to provide a pollutant treatment method and a treatment apparatus that can improve the decomposition efficiency.

  The method for treating a pollutant according to the present invention includes a step of introducing a supercritical carbon dioxide into a first reaction vessel containing a pollutant containing a harmful organic compound to extract the harmful organic compound from the pollutant, and an adsorbent. Introducing a supercritical carbon dioxide in which a harmful organic compound is dissolved in the first reaction tank into the second reaction tank filled with the adsorbent, and adsorbing the harmful organic compound in the adsorbent; And a step of supercritical hydrolytic decomposition of a harmful organic compound adsorbed on the adsorbent by introducing critical water and an oxidant.

  According to the present invention, a step of extracting a harmful organic compound from a contaminant using supercritical carbon dioxide as an extraction solvent, and adsorbing the harmful organic compound in the supercritical carbon dioxide to the adsorbent in the same reaction vessel; And the step of supercritical hydrolytic decomposition of the toxic organic compound adsorbed on the substrate, there is an effect that the toxic organic compound can be combusted and decomposed in a closed system without being scattered outside the processing apparatus. In addition, the concentration of toxic organic compounds in multiple stages enables supercritical hydroxylation decomposition even in high temperature and high pressure environments as in the past, increasing the size of pressure vessels that are problematic in supercritical water application processes. The increase in initial cost due to can be suppressed.

Embodiment 1 FIG.
FIG. 1 is a diagram showing the configuration of a pollutant processing apparatus according to Embodiment 1 of the present invention, and a process and apparatus configuration for supercritical hydrolytic decomposition of harmful organic compounds such as dioxins contained in incineration fly ash Are described in association with each other. As shown in FIG. 1, an extraction tank (first reaction tank) 1 is filled with incinerated fly ash (contaminant) to be treated that has been pretreated (acid treated) and introduced with supercritical carbon dioxide. Extract harmful organic compounds such as dioxins in incineration fly ash by dissolving them in supercritical carbon dioxide. The supercritical carbon dioxide in which the toxic organic compound is dissolved is sent out from the extraction tank 1 to the activated carbon adsorption tank 2 and taken out as incinerated fly ash from which the extraction residue has been rendered harmless (extraction process).

  Supercritical carbon dioxide has a critical temperature of 31.1 ° C., which is close to room temperature, is an inert, non-toxic fluid, and has excellent solubility of organic compounds in a supercritical state. Therefore, in the present invention, it is used as an extraction solvent in the extraction process of harmful organic compounds such as dioxins. Carbon dioxide, which becomes supercritical carbon dioxide, is supplied from a high-pressure pump (first introduction means) 3 as shown in FIG.

  The carbon dioxide supplied from the high-pressure pump 3 is cooled by the cooler 10 interposed in the path between the high-pressure pump 3 and the circulation pump (first introduction means) 4, and is moved to the extraction tank 1 side by the circulation pump 4. After being sent out, the temperature and pressure are controlled by the heater 7 and the back pressure valve (first introduction means) 11 and introduced into the extraction tank 1 as supercritical carbon dioxide. The supercritical carbon dioxide is controlled to a temperature within a temperature range of 30 to 80 ° C. by the heater 7 and is introduced into the extraction tank 1 through the back pressure valve 11 at a pressure within a pressure range of 7 to 60 MPa.

  In addition, the temperature range of 30 to 80 ° C. and the pressure range of 7 to 60 MPa for extracting harmful organic compounds with supercritical carbon dioxide does not reach criticality at the lower temperature and pressure conditions, so that sufficient extraction function is exhibited. However, if the pressure is higher than the upper limit, the pressure vessel constituting the extraction tank 1 is too strong, and it is a suitable range considering that it is difficult to put it to practical use economically.

  Moreover, in the extraction process of harmful organic compounds with supercritical carbon dioxide, an auxiliary solvent such as methanol is injected into the extraction tank 1 and the organic solvent is dissolved in the auxiliary solvent and then extracted with supercritical carbon dioxide. May be. In addition, the extraction tank 1 may be filled with an inert porous granular member such as glass beads or ceramic balls. Thus, by filling the extraction tank 1 with the granular member, the contact property between the incinerated fly ash containing the harmful organic compound and the supercritical carbon dioxide is improved, and the extraction ability of the supercritical carbon dioxide is improved.

  Activated carbon adsorption tank (second reaction tank) 2 provided in the next stage of extraction tank 1 is filled with activated carbon, and harmful organic compounds such as dioxins in supercritical carbon dioxide introduced from extraction tank 1 Is adsorbed onto activated carbon and concentrated, and the concentrated harmful organic compound is supercritically hydrolyzed. Thus, in the pollutant processing apparatus according to Embodiment 1, a trace amount of harmful organic compounds such as dioxins is obtained by combining the extraction capability of harmful organic compounds of supercritical carbon dioxide and wet combustion treatment by supercritical water oxidation reaction. The compound is concentrated and completely burned and decomposed in a sealed pressure vessel (decomposition process).

  In addition, the concentration of supercritical carbon dioxide in which harmful organic compounds such as dioxins are dissolved and supercritical hydroxylation of the concentrated harmful organic compounds are performed in the activated carbon adsorption tank 2 of the same container, so Once the incineration fly ash of the product is once put into the container of the apparatus, the toxic organic compounds in the incineration fly ash are always sealed in the container. Therefore, harmful organic compounds (particularly concentrated harmful organic compounds) are not exposed to the operator who manages the pollutant processing apparatus according to the first embodiment.

  Supercritical carbon dioxide from the extraction tank 1 is introduced into the activated carbon adsorption tank 2 through a pressure reducing valve (first introduction means) 12, and water and oxidant used for supercritical hydroxylation are liquid pumps (second Are introduced into the activated carbon adsorption tank 2 through the preheater 9. Moreover, the activated carbon adsorption tank 2 is comprised from the pressure vessel which can maintain a predetermined pressure, and the heater 8 for controlling the temperature in a tank is provided.

  Adsorption concentration of harmful organic compounds in the activated carbon adsorption tank 2 is performed in the same range of 30 to 80 ° C. as the temperature in the extraction process in the extraction tank 1 and below the design pressure of the activated carbon adsorption tank 2. For example, supercritical carbon dioxide from the extraction tank 1 is introduced into the activated carbon adsorption tank 2 without being depressurized by the pressure reducing valve 12, and is controlled to a temperature within a temperature range of 30 to 80 ° C. by the heater 8. Adsorbs and concentrates harmful organic compounds.

  The supercritical carbon dioxide adsorbed by the activated carbon and from which harmful organic compounds have been removed is returned from the activated carbon adsorption tank 2 to the high-pressure pump 3 along the path indicated by the broken line in FIG. Then, it is sent again to the extraction tank 1 side by the circulation pump 4. Thus, the circulation pump 4 circulates supercritical carbon dioxide between the extraction tank 1 and the activated carbon adsorption tank 2.

  Water is supercritical at 373 ° C., and when oxygen and carbon components are present, it is known to burn in water, so-called wet combustion, and it is possible to burn harmful organic compounds in a closed system. In addition, the supercritical hydrolytic decomposition in this Embodiment 1 is performed within the temperature range of 373-650 degreeC, and within the pressure range of 10-50 Mpa.

  The supercritical carbon dioxide from the extraction tank 1 is introduced into the activated carbon adsorption tank 2 while being controlled to a pressure within the above pressure range by the pressure reducing valve 12, and water and oxidize from the liquid pump 5 as shown by a broken line in FIG. The agent is introduced after being heated by the preheater 9. Further, the inside of the activated carbon adsorption tank 2 is heated to a temperature within the above temperature range by the heater 8, and the concentrated harmful organic compound is supercritically hydrolyzed.

  Note that the temperature range of 373 to 650 ° C. and the pressure range of 10 to 50 MPa at which the supercritical hydroxylation described above is performed cannot sufficiently exhibit the supercritical hydroxylation reaction under the lower temperature and pressure conditions, and the upper limit. The above is a preferable range in consideration of the fact that the pressure vessel is too robust and difficult to put into practical use economically.

  In the above description, the example in which the adsorption concentration is performed at the same temperature as the extraction process in the extraction tank 1 is shown, but the pressure in the extraction process in the extraction tank 1 is higher than the pressure in the decomposition process in the activated carbon adsorption tank 2. Cases are also expected. In this case, the supercritical carbon dioxide from the extraction tank 1 is depressurized by a pressure reducing valve and then introduced into the activated carbon adsorption tank 2 to perform activated carbon adsorption. Thereby, it is possible to design the pressure vessel used as the activated carbon adsorption tank 2 with the design pressure lower than the pressure in extraction processing, and it becomes economically advantageous.

  The treated water after the decomposition treatment is introduced into the gas-liquid separator 6 from the activated carbon adsorption tank 2 through the valve 13 as indicated by a broken line in FIG. In the gas-liquid separator 6, the treated water can be separated into the decomposition gas of the harmful organic compound and the decomposed treated water, and the decomposed treated water can be taken out via the valve 14.

  FIG. 2 is a diagram for explaining the pollutant processing method according to the first embodiment, and shows each processing step in the processing apparatus shown in FIG. As shown in FIG. 2, the pollutant processing method according to the first embodiment is roughly classified into four processes: a pretreatment process, an extraction separation process, an adsorption concentration process, and a decomposition process. Hereinafter, each step will be described.

(1) Pretreatment step (primary concentration of dioxins (DXN))
First, when incinerated fly ash is contaminated with dioxins and heavy metals, the heavy metals are insolubilized by an alkaline component such as calcium and removed as a solid hydroxide. Thereafter, as a pretreatment step, the incineration fly ash is washed with an acid solution (acid washing) to dissolve alkali components such as calcium mixed in the incineration fly ash. At this time, since harmful components such as dioxins are not dissolved in the acid solution, harmful organic compounds in the incineration fly ash are relatively concentrated (primary concentration of dioxins).

  As the acid solution for acid cleaning, for example, a strong acid aqueous solution of hydrochloric acid, sulfuric acid and nitric acid is used. In addition, the acid solution which melt | dissolved the alkaline component in incineration fly ash is detoxified and discharged by water treatment as a waste liquid. The incinerated fly ash enriched with dioxins is dried after acid cleaning and sealed in the extraction tank 1.

(2) Extraction and separation process (secondary concentration of dioxins (DXN))
In the extraction / separation step, supercritical carbon dioxide is circulated as shown in FIG. 1 to extract dioxins from the incineration fly ash in the extraction tank 1 in which the incineration fly ash after the primary concentration of dioxins is enclosed. Since supercritical carbon dioxide is extremely excellent in the solubility of organic compounds as described above, harmful organic compounds such as dioxins are selectively dissolved by flowing through the extraction tank 1. Thereby, harmful organic compounds are concentrated in supercritical carbon dioxide (secondary concentration of dioxins).

  The supercritical carbon dioxide circulated in the extraction tank 1 is set, for example, to a pressure of 50 MPa and a temperature of 40 ° C. As described above, the supercritical carbon dioxide is desirably in a temperature range of 30 to 80 ° C. and a pressure range of 7 to 60 MPa.

(3) Adsorption concentration step (tertiary concentration of dioxins (DXN))
In the adsorption concentration process, supercritical carbon dioxide in which harmful organic compounds such as dioxins discharged from the extraction tank 1 are dissolved is circulated to the activated carbon adsorption tank 2, and the activated carbon filled in the activated carbon adsorption tank 2 is supercritical carbon dioxide. Adsorbs harmful organic compounds. By repeating this adsorption treatment, harmful organic compounds such as dioxins are concentrated in activated carbon to a high concentration (tertiary concentration of dioxins). The supercritical carbon dioxide from the extraction tank 1 has a temperature within the same temperature range of 30 to 80 ° C. as that of the extraction tank 1 when being circulated through the activated carbon adsorption tank 2, and is within a pressure range of 20 to 25 MPa by the pressure reducing valve 12. Reduce the pressure to

(4) Decomposition process (supercritical hydrolysis of harmful organic compounds)
In the decomposition step, harmful organic compounds such as dioxins adsorbed and concentrated on the activated carbon in the activated carbon adsorption tank 2 are supercritically hydrolyzed. Specifically, after toxic organic compounds are adsorbed and concentrated on the activated carbon in the activated carbon adsorption tank 2 in the above-described process, supercritical carbon dioxide is exhausted from the activated carbon adsorption tank 2 and decompressed, and then supercritical water is discharged by the liquid pump 5. And introducing an oxidizing agent. In this way, by contacting the activated carbon with supercritical water to which an oxidizing agent is added, harmful organic compounds such as dioxins are combusted and decomposed together with the activated carbon. As the oxidizing agent, for example, oxygen peroxide, oxygen gas, air or the like is introduced.

  This supercritical hydroxylation is performed, for example, by setting the temperature in the activated carbon adsorption tank 2 to 500 ° C. and the pressure to 25 MPa. As described above, the temperature range for supercritical hydroxylation is preferably 373 to 650 ° C. and the pressure range is preferably 10 to 50 MPa. Below the lower limit of this range, sufficient combustion power cannot be obtained, and above the upper limit, the load on the equipment is high and the cost effect becomes large.

  The treated water after the decomposition step is separated into a decomposition gas of the harmful organic compound and the decomposition treated water by the gas-liquid separator 6. In the example of FIG. 2, the effluent that is the decomposed water is returned to the liquid pump 5 and circulated in the activated carbon adsorption tank 2 in a supercritical state or a subcritical state.

Next, the result of detoxifying incinerated fly ash containing dioxins at a high concentration in the pollutant processing apparatus according to Embodiment 1 will be described.
First, as an extraction test for dioxins, supercritical carbon dioxide was circulated at a temperature of 40 ° C. and a pressure of 50 MPa to extract dioxins from the incinerated fly ash through the extraction tank 1 in which the incinerated fly ash after acid cleaning was enclosed. .

  FIG. 3 is a diagram showing the result of executing the extraction process under the above-described processing conditions, and shows the result of calculating the extraction rate by measuring the dioxin concentration before and after extraction. As shown in FIG. 3, the dioxins concentration (DXNs concentration) in the incineration fly ash before extraction is 46 (ng-TEQ / g), whereas by extracting dioxins under the above-described processing conditions, The dioxin concentration was 0.0019 (ng-TEQ / g), and a high extraction rate of 99.99% or higher was realized.

  Subsequently, supercritical carbon dioxide in which dioxins were dissolved under the above treatment conditions was introduced into the activated carbon adsorption tank 2 at a temperature of 40 ° C. and a pressure of 20 MPa. In this way, it was confirmed that the dioxins were completely adsorbed by the activated carbon without being detected from the carbon dioxide gas after aeration of the activated carbon by adsorbing the dioxins on the activated carbon.

Next, supercritical water to which hydrogen peroxide was added as an oxidizing agent was introduced into the activated carbon adsorption tank 2 to perform supercritical hydroxylation of dioxins.
FIG. 4 is a diagram showing the processing conditions and results of supercritical hydrolysis, and the pressure (decomposition pressure), temperature (decomposition temperature) in the activated carbon adsorption tank 2, the concentration of hydrogen peroxide added as an oxidizing agent, and the flow rate. , Oxygen excess rate, activated carbon amount, reaction time, activated carbon decomposition rate. As is clear from FIG. 4, supercritical water added with hydrogen peroxide solution is brought into contact with activated carbon adsorbed with dioxins and subjected to supercritical hydroxylation, so that 99.8 under any treatment condition. % High decomposition rate was obtained.

  As described above, according to the first embodiment, a supercritical carbon dioxide is extracted from a pollutant using supercritical carbon dioxide as an extraction solvent, and the activated carbon adsorption tank 2 is used as a reaction tank for concentration and decomposition treatment. The process of adsorbing the harmful organic compound in the adsorbent and the process of supercritical hydrolytic decomposition of the harmful organic compound adsorbed on the adsorbent are performed, so that the harmful organic compound is not scattered outside the processing apparatus. It can be burned and decomposed in a closed system. In addition, since hazardous organic compounds are concentrated in multiple stages, supercritical water oxidation can be performed without using high-temperature and high-pressure environments as in the past, and large-scale pressure vessels are a problem in supercritical water application processes. An increase in initial cost due to conversion can be suppressed.

  In addition, with respect to the pollutant processing apparatus shown in the first embodiment, an analyzer that continuously measures the component concentration in the cracked gas, and a measurement that continuously measures the temperature of each part of the activated carbon adsorption tank 2 and the preheater 9. An apparatus may be further provided.

  FIG. 5 is a graph showing the analysis result of the cracked gas by supercritical hydroxylation together with the temperature of the activated carbon adsorption tank, etc., and when the cracking process was performed under the cracking temperature of 425 ° C. and the cracking pressure of 25 MPa in FIG. Shows the results. In FIG. 5, data a is the internal temperature of the activated carbon adsorption tank 2, data b is the temperature at the inlet of the activated carbon adsorption tank 2 where supercritical carbon dioxide is introduced, and data c is a heater provided outside the activated carbon adsorption tank 2. 8, data d indicates the temperature of the preheater 9, and data e indicates the change in the activated carbon temperature with time, and indicates the results measured by the above-described measuring apparatus.

Data f is the concentration (ppm) of carbon monoxide (CO) obtained by continuously analyzing the components in the cracked gas, and data g is obtained by continuously analyzing the components in the cracked gas. The obtained carbon dioxide (CO ₂ ) concentration (%) and data h are oxygen (O ₂ ) concentration (%) obtained by continuously analyzing the components in the cracked gas. The data a to e are measured by the above-described measuring device, and the data f to h are the results of analyzing the components of the separated gas separated from the gas-liquid separator 6 by the analyzing device.

  Supercritical water added with hydrogen peroxide is introduced into the activated carbon adsorption tank 2 and heated by the heater 8 and the preheater 9, and the internal temperature (data a) of the activated carbon adsorption tank 2 is set to a desired temperature (425 ° C.). When the temperature is stabilized, a combustion reaction that is supercritical hydrolytic decomposition is started in the activated carbon adsorption tank 2. As shown in FIG. 5, this can be confirmed from the fact that the oxygen concentration (data h) in the cracked gas decreases as the combustion reaction starts, and conversely the carbon dioxide concentration (data g) increases rapidly.

  Further, after 240 minutes, the oxygen concentration increases, but the carbon dioxide concentration decreases remarkably. Thereby, it can be seen that the combustion reaction is terminated at about 200 minutes after the carbon dioxide concentration has completely decreased from the start of combustion. Thus, the start and end of the combustion reaction can be determined by monitoring the data as shown in FIG. 5, particularly the change in the concentration of oxygen and carbon dioxide in the cracked gas. Therefore, the state of the combustion reaction is automatically determined based on, for example, the concentration change of oxygen and carbon dioxide in the cracked gas with respect to the pollutant processing apparatus shown in the first embodiment, and the temperature and gas of the activated carbon adsorption tank 2 are determined. A control device for controlling the introduction may be provided.

It is a figure which shows the structure of the processing apparatus of the pollutant by Embodiment 1 of this invention. 5 is a diagram for explaining a pollutant treatment method according to Embodiment 1. FIG. It is a figure which shows the result of having performed extraction processing. It is a figure which shows the process conditions and result of a supercritical hydroxylation. It is a graph which shows the analysis result of the cracked gas by supercritical hydroxylation decomposition | disassembly with temperature, such as an activated carbon adsorption tank.

Explanation of symbols

1 Extraction tank (first reaction tank)
2 Activated carbon adsorption tank (second reaction tank)
3 High-pressure pump 4 Circulation pump (first introduction means)
5 Liquid pump (second introduction means)
6 Gas-liquid separator 7, 8 Heater 9 Preheater 10 Cooler 11 Back pressure valve (first introduction means)
12 Pressure reducing valve (first introduction means)
13, 14 valves

Claims (8)

Introducing a supercritical carbon dioxide into a first reaction vessel containing a pollutant containing a harmful organic compound to extract the harmful organic compound from the pollutant;
Introducing a supercritical carbon dioxide in which a harmful organic compound is dissolved in the first reaction tank into a second reaction tank filled with an adsorbent to adsorb the harmful organic compound to the adsorbent;
A method for treating contaminants comprising a step of introducing supercritical water and an oxidizing agent into the second reaction tank and supercritically hydrolyzing a harmful organic compound adsorbed on the adsorbent. Introducing supercritical carbon dioxide at a temperature of 30 to 80 ° C. and a pressure of 7 to 60 MPa into the first reactor to extract harmful organic compounds from pollutants,
The contamination according to claim 1, wherein supercritical water and an oxidizing agent at a temperature of 373 to 650 ° C and a pressure of 10 to 50 MPa are introduced into the second reaction tank to supercritically hydrolyze harmful organic compounds. How to treat the substance.   The method for treating contaminants according to claim 1 or 2, wherein the contaminants are acid-washed with a strong acid aqueous solution and then accommodated in the first reaction tank.   The method for treating a pollutant according to any one of claims 1 to 3, wherein an auxiliary solvent that dissolves a harmful organic compound in the pollutant is injected into the first reaction tank.   The pollutant processing method according to any one of claims 1 to 4, wherein the first reaction tank is filled with an inert porous granular member. A first reaction vessel containing a pollutant containing a toxic organic compound;
A second reaction vessel filled with an adsorbent;
Supercritical carbon dioxide is introduced into the first reaction tank, and supercritical carbon dioxide in which a harmful organic compound is dissolved in the first reaction tank is introduced into the second reaction tank. First introducing means for adsorbing harmful organic compounds in the adsorbent;
A pollutant treatment apparatus comprising: a second introduction unit that introduces supercritical water and an oxidant into the second reaction tank and supercritically decomposes a harmful organic compound adsorbed on the adsorbent. In the first reaction vessel, harmful organic compounds are extracted from pollutants with supercritical carbon dioxide at a temperature of 30 to 80 ° C. and a pressure of 7 to 60 MPa,
7. The supercritical water-soluble decomposition of a harmful organic compound by introducing supercritical water and an oxidizing agent at a temperature of 373 to 650 ° C. and a pressure of 10 to 50 MPa in the second reaction tank. Contaminant treatment equipment.   An analysis means for continuously measuring components in a cracked gas generated by supercritical hydrolysis is provided, and the progress of supercritical hydrolysis is determined according to the measurement result of the analysis means. The apparatus for processing a pollutant according to claim 6 or 7.

Images