JP2011058874A - Electromagnetic induction heating toc removing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic induction heating TOC removing device having high thermal efficiency and superior controllability. <P>SOLUTION: The electromagnetic induction heating TOC removing device 1 removes at least an organic carbonaceous material (TOC) from a waste liquid includes: a distillation still 2 performing vacuum distillation of the waste liquid and fractionating it into a residue containing organic carbonaceous materials and vapor; and an electromagnetic induction coil 3 provided at the distillation still 2 and heating the waste liquid in the distillation still 2 to a distillation temperature by electromagnetic induction heating of the distillation still 2 itself. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electromagnetic induction heating type TOC (Total Organic Carbon) removal device that removes at least organic carbon material from waste liquid, and relates to an electromagnetic induction heating type TOC removal device that can remove radioactive materials together with organic carbon material. About.

  The nuclear facilities generate low-level radioactive liquid waste, such as the waste liquid that was used to clean the tools and pipes used in the radiation control area of the facility. The radioactive liquid waste must be stored in the power plant premises or stored for a long period of time if the radioactivity level does not decrease to the specified standard, and should be processed in a normal water treatment facility. It is a rule that can not be.

  In recent years, it has been required not only to remove radioactive substances, but also to reduce the TOC concentration in the waste liquid to a standard defined by prescribed laws and regulations. Regarding the removal of TOC, Patent Document 1 discloses a catalyst obtained by wet decomposition of radioactive organic waste by the action of hydrogen peroxide on radioactive organic waste made of filter sludge or ion exchange resin membrane generated from a nuclear power plant. A method is disclosed in which it is treated with a combustion device and separated into condensed water containing no TOC and harmless and odorless exhaust gas.

  Regarding the removal of radioactive substances and COD, Patent Document 2 describes that after radioactive wastewater is oxidized and insolubilized, it is separated into solid and liquid by filtration, gravity sedimentation, coagulation sedimentation, centrifugal separation or flotation separation. A method of removing is disclosed.

  Regarding the removal of radioactive substances, Patent Document 3 discloses a method of concentrating radioactive waste liquid with a distiller, sending the distilled liquid to a desalting tower, purifying it, and releasing it from the system, while solidifying the concentrated liquid. ing.

  In general, in a distillation apparatus that performs pressure reduction, a sealed oil and a resistor have resistance, and when the resistor is energized, the resistor is heated to heat the oil, and the heated oil distills the distillation. It is heated using an oil heater or steam heater that heats the kettle.

JP 2000-65986 A JP 2002-228895 A JP-A-3-13897

  In Patent Document 1, there is no description regarding waste liquid treatment or removal of radioactive substances, and the processing object of the invention according to the document is solid waste, particularly radioactive organic waste, composed of filter sludge or ion exchange resin membrane. It is not a liquid waste.

  Patent Document 2 describes a method for removing radioactive substances and COD-causing substances by filtration, gravity sedimentation, or the like. However, in solid-liquid separation methods such as filtration and gravity sedimentation, it is difficult to convert waste liquid having a TOC concentration of the order of 10,000 ppm into purified water having a TOC concentration of the order of 10 ppm. In addition, when a filtration filter is immediately used to remove radioactive substances, the filtration filter is radioactively contaminated, and on the contrary, there is a problem that radioactive waste increases.

  Patent Document 3 has no description regarding TOC and its removal.

  In addition, when the distillation kettle is heated by an oil heater or a steam heater, there is a problem that the heat efficiency is lowered because of indirect heating. This is because it is necessary to preheat a heat storage body such as oil or steam to a predetermined temperature, and a large amount of heat is dissipated in the process of heating the heat storage body. This causes another problem that it is difficult to quickly control the temperature rise and fall of the still.

  An object of the present invention is to provide an electromagnetic induction heating type TOC removing device having high thermal efficiency and excellent controllability. Another object of the present invention is to provide an electromagnetic induction heating type TOC removal device that has high thermal efficiency, excellent controllability, and can remove radioactive materials together with TOC.

  The present invention, in a first aspect, is an apparatus for removing at least an organic carbon substance from a waste liquid, wherein the waste liquid is distilled under reduced pressure to fractionate the residue containing the organic carbon substance and steam, An electromagnetic induction heating type TOC removing device, which is attached to the distillation kettle and has an electromagnetic induction coil that heats the waste liquid in the distillation kettle to a temperature at which the distillation kettle can be distilled by electromagnetic induction heating. To do.

  The present inventors have proposed a method and an apparatus for removing radioactive substances and TOC using vacuum distillation in Japanese Patent Application No. 2008-090796 filed on Mar. 31, 2008 (for example, claim) Paragraphs 1 and 7 and paragraph 0024 of the description). Furthermore, as a result of research, the present inventors have succeeded in developing a removal device such as TOC that has high thermal efficiency and good controllability.

  According to the electromagnetic induction heating type TOC removing device of the present invention, when an electromagnetic induction coil attached to the distillation pot is energized, an induction current is generated in the distillation pot and the distillation pot itself generates heat. Thus, the amount of heat escaping to the outside of the distillation kettle is reduced by directly heating the distillation kettle. In addition, unlike an oil heater or the like, an electromagnetic induction coil does not require preheating of a heat medium. Therefore, according to the electromagnetic induction heating type TOC removal apparatus of the present invention, not only the thermal efficiency during vacuum distillation but also startup and further increase The overall thermal efficiency from the temperature to the end of vacuum distillation is greatly improved, and a thermal efficiency of 80% or more (see Example 6) can be obtained.

  In addition, the electromagnetic induction coil can be heated locally and quickly compared to an oil heater that warms the whole or a wide space. In the heat treatment for vacuum distillation, for example, the amount and type of waste liquid to be treated Various controls can be performed accordingly. Furthermore, since the electromagnetic induction coil can be easily turned on / off and the output level can be adjusted, and the temperature of the distillation pot or the waste liquid therein can be easily controlled. Accordingly, the vacuum distillation can be performed safely with maximum thermal efficiency. In vacuum distillation, the pressure in the distillation pot may be reduced to a vacuum or a pressure close to vacuum.

  Generally, in the radiation control area of a nuclear power plant, the installation space for the cleaning device is limited. When the cleaning device is enlarged, the installation space for other devices is reduced. The present invention makes it easy to increase the size of the TOC removal device by using an electromagnetic induction coil, and can quickly increase the temperature of the TOC removal device. can do.

  By distillation under reduced pressure, TOC is contained in the residue, not in the vapor or the distillate, and, for example, clean distilled water having a pure water level that can be discharged or reused can be obtained. Further, since other substances are adsorbed on the TOC in the residue, extra substances other than the TOC can be removed according to the vacuum distillation of the present invention.

  Further, according to the electromagnetic induction heating type TOC removing apparatus of the present invention, the radioactive liquid waste containing the organic carbon substance is distilled under reduced pressure to separate the residue and the distillate, similarly to the apparatus of Japanese Patent Application No. 2008-090796 described above. It is possible to produce the distillate from which the radioactive substance is removed and the organic carbon substance is reduced by adding the radioactive substance together with the organic carbon substance to the residue. Vacuum distillation of such a radioactive liquid waste containing an organic carbon substance has the following advantages.

(1) Since the waste liquid can be fractionated into a residue and a distillate by low-temperature treatment by vacuum distillation of the radioactive waste liquid, scattering of radioactive substances is prevented.
(2) Since the radioactive substance and the organic carbon substance are included in the residue in a mixed state, efficient removal of both is achieved, and the cleanliness on the distillate side is improved.
(3) When the radioactive waste liquid is directly applied to a filtering means, for example, a filtration filter, the filtration filter is largely contaminated with radioactive substances, and this filtration filter becomes radioactive waste. On the contrary, the radioactive waste increases. There is a problem. However, according to the present invention, since radioactive waste liquid is first distilled under reduced pressure to remove radioactive substances, occurrence of such a problem is prevented.
(4) By distilling the radioactive liquid waste under reduced pressure, a distillate having a TOC concentration of 10 ppm or less, preferably 5 ppm or less can be obtained, and furthermore, pure water having a TOC concentration of 1 ppm or less and a detection limit value or less is obtained. Is easy (see Example 7). As a result, it can be released into public waters such as lakes, rivers, and seas throughout the country. According to the water quality standard based on the Water Supply Law (2008 Ministry of Health, Labor and Welfare Ordinance No. 174), organic matter (TOC) is defined as 3 mg / l (3 ppm) or less. In the Water Pollution Control Law, there are BOD (Biochemical Oxygen Demand) and COD (Chemical Oxygen Demand) as indicators that represent the amount of organic substances in water. These wastewater standards are both 160 mg / l ( Daily average of 120 mg / l) or less [a value that is almost similar even when evaluated by TOC].
(5) Since the liquid is removed from the residue containing radioactive material, the volume of radioactive waste is reduced. On the other hand, the distillate can be reused or processed at the on-site water treatment facility such as a nuclear facility or easily. The TOC and radioactive material are removed to a reasonable level. Moreover, the obtained distillate can be reused as a diluent for a cleaning solution for radioactive contaminants.

(A) And (B) is explanatory drawing which shows the structure of the electromagnetic induction heating type TOC removal apparatus which concerns on one Example of this invention, (A) is a front view, (B) is a side surface. FIG. It is a block diagram explaining the detailed structure of the electromagnetic induction heating type TOC removal apparatus shown in FIG. It is a flowchart for demonstrating operation | movement of the electromagnetic induction heating type TOC removal apparatus shown in FIG.1 and FIG.2. It is a control diagram which shows an example of the operation pattern for maintaining the liquid level height of a waste liquid in the electromagnetic induction heating type TOC removal apparatus which concerns on one Example of this invention.

  In a preferred embodiment of the present invention, the electromagnetic induction coil is composed of a plurality of electromagnetic induction coil units divided at least in the vertical direction. According to this form, for example, by turning on (energizing) only the electromagnetic induction coil unit necessary for vacuum distillation among the plurality of electromagnetic induction coil units, and turning off (energization stop) unnecessary electromagnetic induction coil units, Energy saving and overheating of the still can be prevented.

  In preferable embodiment of this invention, it has a control part which can control individually on / off of these electromagnetic induction coil units divided | segmented into the up-down direction according to the liquid level height of the waste liquid in the said distillation pot. . According to this embodiment, for example, one or a plurality of electromagnetic induction coil units located above the liquid level of the waste liquid in the distillation pot are turned off to save energy and prevent the distillation tank from overheating. be able to. The height of the waste liquid level can be detected by using a plurality of temperature sensors that can detect the partial temperature of the distillation kettle, or other types of liquid level detection sensors.

  In a preferred embodiment of the present invention, the electromagnetic induction coil is composed of a plurality of electromagnetic induction coil units divided at least in the vertical direction, a temperature sensor for detecting the temperature of the distillation kettle, and a temperature by the temperature sensor And a control unit capable of individually controlling on / off of the plurality of electromagnetic induction coil units divided in the vertical direction based on the detection. According to this embodiment, the temperature sensor is used to detect, for example, the liquid level height of the waste liquid in the distillation kettle or the amount of the waste liquid, and based on this detection, only the electromagnetic induction coil unit necessary for vacuum distillation is detected. By turning on and turning off unnecessary electromagnetic induction coil units, energy can be saved and overheating of the still can be prevented. In addition, the number of sensors can be reduced.

  In a preferred embodiment of the present invention, the temperature sensor includes a plurality of temperature sensors respectively attached to the plurality of electromagnetic induction coil units, and each of the temperature sensors includes the electromagnetic sensor to which the temperature sensor is attached. A partial temperature of the distillation pot near the induction coil unit can be detected. According to this embodiment, the partial temperature of the distillation kettle is detected using a plurality of temperature sensors, and only the electromagnetic induction coil unit necessary for vacuum distillation is turned on based on this detection, and unnecessary electromagnetic induction is performed. By turning off the coil unit, energy can be saved and overheating of the still can be prevented.

  In a preferred embodiment of the present invention, waste liquid is additionally supplied to the distillation kettle according to the partial temperature of the distillation kettle detected by the plurality of temperature sensors. As a result, the amount of waste liquid treated per hour is increased, and overheating of the still is prevented. In addition, the liquid level sensor detects the level of the liquid level in the distillation pot or waste liquid tank, and controls the supply of the waste liquid to the distillation pot based on that level, or measures the amount of distillation and supplies additional liquid. May be.

  Generally, under conditions where distillation occurs, if one of temperature and pressure is determined, the other is determined. That is, in the present invention, in order to generate the vacuum distillation, the pressure and temperature may be set corresponding to each other based on the vapor pressure curve determined by the type of waste liquid. Basically, in vacuum distillation, when the pressure is set relatively high, the temperature is set at a relatively high temperature, and when the pressure is set relatively low, the temperature may be set at a relatively low temperature. However, in the vacuum distillation of the present invention, it is preferable to set the pressure and temperature in consideration of, for example, the vacuum distillation treatment time so that the vacuum distillation is industrially effective. Furthermore, it is preferable to determine the pressure and temperature in the vacuum distillation in consideration of the prevention of mixing of the substance as a residue into the distillate side, the pressure resistance of the distillation kettle and the pumping capacity for reducing the pressure. Moreover, it is preferable to determine distillation conditions based on the viewpoint that accidents such as fires are highly prevented when the temperature is set low, and the processing time is shortened when the temperature is high.

  In a preferred embodiment of the present invention, when the waste liquid or radioactive waste liquid is aqueous and the resulting distillate is distilled water, the temperature of the vacuum distillation is 20 to 85 ° C, preferably 30 to 80 ° C, more preferably. The pressure is set in the range of 40 to 60 ° C., and the pressure at this time is basically determined according to the temperature range with reference to the vapor pressure curve of water. For example, the pressure of vacuum distillation is basically set to 0.0023 to 0.057 MPa, preferably 0.0041 to 0.047 MPa, and more preferably 0.0072 to 0.02 MPa. Moreover, you may set the pressure of vacuum distillation to the pressure near a vacuum or a vacuum.

  In a preferred embodiment of the present invention, the waste liquid or radioactive waste liquid is an aqueous or organic solvent system. For example, trichloroethylene or perchloroethylene is exemplified as the organic solvent. The temperature and pressure of the vacuum distillation may be basically determined based on the vapor pressure curve of the organic solvent.

  The radioactive waste liquid treated by the present invention is, for example, a waste liquid after decontaminating radioactive contaminants with an aqueous or organic solvent-based decontamination liquid.

  In a preferred embodiment of the present invention, the TOC concentration of the obtained distillate is at least 10 ppm or less, preferably 5 ppm or less. More preferably, it is easy to filter the distillate so that the TOC concentration of the distillate is 1 ppm or less.

  In a preferred embodiment of the present invention, the distillate from which radioactive substances have been removed is generated. In addition, the radioactive substance concentration in the distillate from which the radioactive substance has been removed is less than the detection limit value by the 3σ method.

  In a preferred embodiment of the present invention, the organic carbon contained in the residue is an organic carbon substance adhering to radioactive contaminants, an organic carbon substance contained in a decontamination liquid decontaminated with radioactive contaminants, and / or The organic carbon substance contained in the additive added before vacuum distillation originates. For example, the organic carbon contained in the residue is derived from organic substances contained in scales and rust attached to radioactive contaminants, organic acids contained in decontamination liquid, or additives such as oil cleaning agents. This organic carbon (TOC) and radioactive material are present in the residue by chemical or physical adsorption.

  In a preferred embodiment of the present invention, before the distillation under reduced pressure, a neutralizing agent is added according to the pH of the waste liquid or radioactive waste liquid, and the residue contains the components of the neutralizing agent. As a result, the obtained distillate is neutralized and can be easily treated or discharged. Moreover, in the obtained residue, a radioactive substance exists in the organic carbon substance in the neutralizing agent by chemical or physical adsorption. Moreover, the electromagnetic induction heating type TOC removal apparatus which concerns on preferable embodiment of this invention has the neutralization means which performs the said neutralization process, for example, a neutralization tank.

  For example, when the radioactive liquid waste is acidic, calcium hydroxide or sodium hydroxide may be added as the neutralizing agent, and when it is alkaline, an acid may be added.

  In a preferred embodiment of the present invention, the atmosphere or treatment time of vacuum distillation is adjusted so that the distillation liquid is 95% or more and the residue is 5% or less with respect to 100% of the radioactive waste liquid.

  In a preferred embodiment of the present invention, the temperature and pressure of vacuum distillation and the distillation time are set so that the liquid content of the residue, for example, the water content is 30% or less, more preferably 10% or less. In addition, if distillation time is lengthened, the liquid content rate of a residue can be reduced (as a result, a residue is also reduced).

  In a preferred embodiment of the present invention, the distillate obtained by distillation under reduced pressure is filtered. This further removes organic carbon material from the distillate, further reducing the TOC concentration. In the electromagnetic induction heating type TOC removing apparatus according to a preferred embodiment of the present invention, for example, a carbon filter and an ion exchange resin are arranged in one or more stages as filtration means.

  In an electromagnetic induction heating type TOC removing apparatus according to a preferred embodiment of the present invention, an electromagnetic induction heating device as a heating means or a heat source of a distillation pot, a pump or an ejector as a decompression means of the distillation pot, and a distillate tank as a distillate recovery means Each of the residue containers is used as a residue collecting means.

  An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B are schematic views showing a configuration of an electromagnetic induction heating type TOC removing apparatus according to an embodiment of the present invention. FIG. 1A is a front view, FIG. (B) is a side view.

  Referring to FIGS. 1A and 1B, an electromagnetic induction heating TOC removing apparatus 1 according to an embodiment of the present invention is an apparatus that removes at least an organic carbon substance (TOC) from a waste liquid. The waste liquid is distilled under reduced pressure, and the distillation pot 2 attached to the distillation pot 2 and the distillation pot 2 for fractionating into an organic carbon substance-containing residue and steam, and by heating the distillation pot 2 itself by electromagnetic induction heating, And an electromagnetic induction coil 3 for heating the waste liquid to a temperature at which it can be distilled.

  The electromagnetic induction coil 3 includes first to fifth electromagnetic induction coil units 3a to 3e that are divided in the vertical direction. The first to fifth electromagnetic induction coil units 3 a to 3 e are attached to the outer peripheral surface on the bottom side of the distillation still 2 at a pitch of about 30 degrees. The first to fifth electromagnetic induction coil units 3 a to 3 e extend along the central axis direction of the distillation pot 2. As shown in FIG. 1B, the first to fifth electromagnetic induction coil units 3a to 3e each incorporate an induction coil 30. When an alternating current is applied to the induction coil 30, an induced current flows through the distillation pot 2, and the distillation pot 2 itself generates heat. In the vacuum distillation step, since preheating of the first to fifth electromagnetic induction coil units 3a to 3e is basically unnecessary, the thermal efficiency of the electromagnetic induction heating type TOC control device 1 is improved.

  Furthermore, the electromagnetic induction heating type TOC removing device 1 includes a temperature sensor 4 that detects the temperature of the distillation pot 2, and first to fifth electromagnetic induction coils that are divided in the vertical direction based on temperature detection by the temperature sensor 4. And a control unit (control panel) 5 that can individually control ON / OFF (energization and stoppage) of the units 3a to 3e. During heating, the control unit 5 can selectively turn off the first to fifth electromagnetic induction coil units 3a to 3e that are no longer necessary, thereby improving the thermal efficiency and saving energy. Moreover, the control part 5 may adjust the output degree of the 1st-5th electromagnetic induction coil units 3a-3e.

  The temperature sensor 4 includes first to fifth temperature sensors 4a to 4e that are attached to or adjacent to the first to fifth electromagnetic induction coil units 3a to 3e, respectively, and are installed on the outer peripheral surface of the distillation still 2. Yes. Each of the first to fifth temperature sensors 4a to 4e can detect the partial temperature of the distillation pot 2 in the vicinity of the first to fifth electromagnetic induction coil units 3a to 3e to which the first to fifth temperature sensors 4a to 4e are attached.

  The partial temperature of the still 2 varies depending on the level of the waste liquid. In particular, when the vacuum distillation process proceeds and the waste liquid in the distillation pot 2 decreases, the wall surface of the distillation pot 2 located above the liquid level of the waste liquid becomes relatively high. Therefore, the control unit 5 detects the level of the waste liquid in the still 2 from the partial temperature of the still 2 detected by the first to fifth temperature sensors 4a to 4e. Accordingly, on / off of the first to fifth electromagnetic induction coil units 3a to 3e divided in the vertical direction can be individually controlled.

  Furthermore, the detailed structure of the electromagnetic induction heating type TOC removing apparatus shown in FIG. 1 will be described. FIG. 2 is a block diagram illustrating a detailed configuration of the electromagnetic induction heating TOC removing apparatus shown in FIG. Referring to FIG. 2, the electromagnetic induction heating type TOC removing apparatus 1 shown in FIG. 1 includes additive tanks 11 a, 11 b,... A waste liquid tank 12 for storing waste liquid to be treated, an additive tank 11b and a waste liquid tank 12, connected to a neutralization tank 13 for neutralizing the waste liquid as appropriate, and a waste liquid from the waste liquid tank 12, or from a neutralization tank 13 The neutralized waste liquid is supplied through the waste liquid injection port 2a. In some cases, the distillation tank 2 to which the additive is supplied from the additive tank 11a and the upper space in the distillation tank 2 are connected through the steam port 2b. A condenser 6 for condensing the vapor generated by the vacuum distillation by heat exchange to generate a distillate, a vacuum pump 7 for reducing the pressure in the distillation tank 2 or the distillation system pipe via the condenser 6, and a condenser 6, a buffer tank 8 that temporarily stores the generated distilled water or prevents sudden pressure fluctuations, etc., and a residue generated on the bottom surface of the distillation kettle 2 installed at the lower side of the distillation kettle 2 Are scraped out by operating the piston 9a, a residue discharger 9 that can be discharged to the external residue container 14, a filter 15 that is connected to the buffer tank 8 and can filter the distillate, and a power source (not shown) The IH inverter 16 that is electrically connected between the fifth electromagnetic induction coil units 3a to 3e and is controlled by the control unit 5 to generate a high-frequency current, and the first to fifth temperature sensors 4a to 4e output. On the basis of the detection signal, the controller 5 controls the on / off of the first to fifth electromagnetic induction coil units 3a to 3e via the IH inverter 16, and further controls the operation of the decompression pump 7.

  For example, when the waste liquid is acidic or alkaline, the waste liquid is supplied to the neutralization tank 13 and the neutralizing additive is added and mixed to adjust the pH. When the waste liquid is neutral, the waste liquid may be fed directly from the waste liquid tank 12 into the distillation pot 2. The waste liquid supplied to the distillation kettle 2 may be a stock solution or may be pretreated such as neutralization and oil removal. Further, various additives such as an antifoaming agent and a neutralizing agent can be supplied from the additive tanks 11a, 11b,. The buffer tank 8 temporarily stores the distillate and prevents sudden pressure fluctuations. The decompression pump 7 can decompress the inside of the distillation pot 2 to a predetermined pressure and maintain the pressure in the buffer tank 8 at about atmospheric pressure. The distillate in the buffer tank 8 may be circulated and supplied to the distillation pot 2.

  FIG. 3 is a flowchart for explaining the operation of the electromagnetic induction heating type TOC removing apparatus shown in FIGS. 1 and 2. The operation of the electromagnetic induction heating type TOC removing apparatus according to the embodiment of the present invention shown in FIGS. 1 and 2 will be described with reference to FIG.

[Decompression]
In step S <b> 1, the control unit 5 operates the decompression pump 7 to decompress the distillation pot 2. By reducing the pressure in the distillation pot 2, the liquid components in the waste liquid can be vaporized at a relatively low temperature, so that the safety of operation is high and the scattering of radioactive substances and the like is prevented.

[Waste liquid supply]
In step S <b> 2, waste liquid is supplied into the distillation still 2 from the waste liquid tank 12 or via the neutralization tank 13. Preferably, the liquid level of the waste liquid in the distillation pot 2 is such that the height of the liquid level corresponds to the height of the fourth and fifth electromagnetic induction coil units 3d and 3e located at the top. Is fed into the still 2 until it slightly exceeds. The supply of the waste liquid can be performed intermittently or continuously by a liquid supply pump (not shown) controlled by the control unit 5 or vacuum suction.

[Induction heating start]
In step S <b> 3, the control unit 5 energizes all the first to fifth electromagnetic induction coil units 3 a to 3 e (on-controls them). When a high-frequency current is applied to the first to fifth electromagnetic induction coil units 3a to 3e, an induction current is generated in the distillation pot 2, and the distillation pot 2 itself generates heat. The temperature of the waste liquid reaches a predetermined temperature at which vaporization is possible. In addition, since preheating of the first to fifth electromagnetic induction coil units 3a to 3e is unnecessary, the thermal efficiency of the electromagnetic induction heating type TOC removing device 1 is remarkably improved.

[Start vacuum distillation]
When the temperature of the waste liquid in the still 2 reaches a predetermined temperature (ideally, a saturated steam temperature at a predetermined pressure in the still 2), a vacuum distillation process is started in step S4. That is, when the inside of the distillation pot 2 is depressurized to a predetermined pressure and the waste liquid reaches a distillation temperature corresponding to the predetermined pressure, the vaporized liquid component in the waste liquid becomes vapor and enters the condenser 6 from the inside of the distillation pot 2. The condensed liquid is condensed by the condenser 6 and temporarily stored in the buffer tank 8. As the vacuum distillation progresses, the liquid level of the waste liquid decreases.

[Electromagnetic induction coil unit control]
In steps S5 to S10, the control unit 5 controls the first to fifth electromagnetic induction coil units 3a to 3e via the IH inverter 16 based on the detection signals output from the first to fifth temperature sensors 4a to 4e. Control energization and its stop (on / off). In other words, in step S5, the control unit 5 determines that the fourth or fifth temperature sensor 4d or 4e located at the uppermost part is empty of the first temperature T1 (= the temperature sensor 4d or 4e part of the distillation pot 2 is empty. If it is detected, it is determined that the level of the waste liquid has reached a position lower than that of the fourth or fifth electromagnetic induction coil unit 3d or 3e. In step S6, the energization of the fourth or fifth electromagnetic induction coil unit 3d or 3e is stopped. When the fourth or fifth temperature sensor 4d or 4e does not detect the first temperature T1, the energization of the fourth or fifth electromagnetic induction coil unit 3d or 3e is continued.

  In step S7 following step S5 or S6, the control unit 5 determines whether or not the second or third temperature sensor 4b or 4c located in the middle stage has detected the first temperature T1. Is determined that the liquid level of the waste liquid has reached a position lower than that of the second or third electromagnetic induction coil unit 3b or 3c, and the second or third electromagnetic induction coil unit 3b is determined in step S8. Or energization of 3c is stopped. When the second or third temperature sensor 4b or 4c does not detect the first temperature T1, energization of the second or third electromagnetic induction coil unit 3b or 3c is continued.

  In step S9 following step S7 or S8, the control unit 5 determines whether or not the first temperature sensor 4a located at the bottom has detected the first temperature T1. It is determined that the surface height has reached a position lower than that of the first electromagnetic induction coil unit 3a, the energization of the first electromagnetic induction coil unit 3a is stopped in step S10, and the vacuum distillation process is ended. .

  In this manner, only the electromagnetic induction coil unit positioned below the liquid level is energized and positioned above the liquid level according to the liquid level height (waste liquid remaining amount) of the waste liquid in the distillation still 2. The energization of the electromagnetic induction coil unit is stopped. As a result, the thermal efficiency of the electromagnetic induction heating type TOC removing device 1 is remarkably improved, and overheating of the distillation pot 2 is prevented.

[Residue]
By the vacuum distillation process described above, a residue containing the TOC contained in the waste liquid remains at the bottom in the distillation pot 2. When the piston 9a is stroked, the residue opens the residue discharger valve and falls into the residue container 14.

[Distillate]
Thus, TOC can be removed from the distillate up to the detection limit. Therefore, the distillate from the buffer tank 8 and, depending on the case, the distillate through the filter 15 can be reused in normal or existing facilities. The distillate can also be discharged into public waters such as lakes, rivers, and seas throughout the country.

  When the waste liquid to be distilled under reduced pressure is a radioactive waste liquid, the residue contains a radioactive substance in a state of being adsorbed on the TOC. In this way, the radioactive substance is removed from the vaporized distillate by containing the radioactive substance together with the organic carbon substance in the residue. Thereby, even when the filter 15 is used, the radioactive substance is not adsorbed on the filter 15, and therefore the filter 15 can be disposed of in a normal manner.

[Test run]
An electromagnetic induction heating type TOC removing device according to an embodiment of the present invention is manufactured, and after the waste liquid is first supplied to the distillation kettle, the waste liquid is not additionally supplied, and the vacuum distillation process is performed according to the process shown in FIG. As the liquid level of the waste liquid decreased, power supply to the electromagnetic induction coil unit below the liquid level was stopped, and the change in the amount of waste liquid treated was measured. The conditions for the test run are as follows.

[Test run conditions]
Distillation kettle material: SUS430
Heating means: Electromagnetic induction coil unit 7kW x 5 units Heating temperature of waste liquid 40 ℃ (room temperature 20 ℃ → distillation temperature 60 ℃)
Specific heat of waste liquid: 1.0
Waste heat of vaporization: 539.35 cal / g
Waste liquid TOC concentration: 19,000 ppm before treatment (not detected after treatment)
Degree of vacuum: -91 to -93 kPa

[Test run results]
As a result of the trial operation, the waste liquid treatment amount when the five electromagnetic induction coil units 3a to 3e (see FIG. 2) were fully operated was about 41 liter / h. With the progress of the vacuum distillation process, the liquid level of the waste liquid was lowered, and the waste liquid treatment amount when only the three electromagnetic induction coil units 3a to 3c were energized was about 30 liter / h.

  When the number of operating electromagnetic induction coil units 3a to 3e decreases, the waste liquid processing amount decreases. In order to prevent this, an operation pattern in which the liquid level of the waste liquid is automatically maintained is set as follows so that the state where all the electromagnetic induction coil units 3a to 3e are energized is maintained.

  FIG. 4 is a control diagram showing an example of an operation pattern for maintaining the liquid level of the waste liquid in the electromagnetic induction heating type TOC removing apparatus according to one embodiment of the present invention.

  Referring to FIGS. 2 and 4, the control unit 5 determines whether or not the inside of the distillation pot 2 is at the time of vacuum distillation based on the detection output of the temperature sensor 4 (4 a to 4 e) or the liquid level sensor installed in the waste liquid tank 12 or the like. The liquid level of the waste liquid is maintained, that is, the liquid feed pump 17 connected to the waste liquid tank 12 is controlled so that the liquid level is the same as or above the uppermost temperature sensors 4d and 4e, The waste liquid can be additionally supplied into the distillation pot 2. Preferably, a combination of the waste liquid additional supply operation pattern shown in FIG. 4 and the overheat prevention control shown in FIG. 2 allows a large amount of waste liquid to be safely distilled under reduced pressure.

  The thermal efficiency of the electromagnetic induction heating type TOC removing apparatus according to one embodiment of the present invention was calculated under the following conditions. As a comparative example, thermal efficiency was calculated when an oil heater was used instead of the electromagnetic induction coil of this example. In addition, the following thermal efficiency calculation does not consider the amount of heat required for preheating regarding the thermal efficiency during vacuum distillation.

[Calculation condition]
(1) Preconditions Waste liquid heating temperature 40 ° C (room temperature 20 ° C → distillation temperature 60 ° C)
Specific heat of waste liquid: 1.0
Waste heat of vaporization: 539.35 cal / g
(2) Formula for calculating thermal efficiency:
Electricity amount × (860 kcal × thermal efficiency) = generated heat amount generated heat amount = distillation processing amount × heating temperature × specific heat + heat of vaporization + distillation processing amount (3a) Conditions of electromagnetic induction heating type TOC removal device “Example”
Distilling pot rating: 30-50 liters / h
Heating means: Electromagnetic induction coil unit 7kW x 5 units (all units on)
Waste liquid treatment amount: 41 l / h (set based on the result of Example 1)
(3b) Conditions for oil heater heating type TOC removal device “Comparative example”
Distilling pot rating: 8-10 liters / h
Heating means: Oil heater 8kW
Waste liquid treatment amount: 8 liters / h (set based on actual operation)

  When the thermal efficiency is calculated under the above-described conditions, the thermal efficiency of the electromagnetic induction heating TOC removal device using the electromagnetic induction coil according to the present embodiment is 79%, and the thermal efficiency of the oil heater heating TOC removal device according to the comparative example is 63%. That is, according to the electromagnetic induction heating type TOC removing apparatus of this example, a significant improvement in thermal efficiency of 15% or more (relative value of 25% or more) was achieved. In addition, since the oil heater of the comparative example requires preheating of oil, it is considered that the overall thermal efficiency including preheating is further superior to the electromagnetic induction heating type TOC removing device according to the present embodiment. The

  Using the electromagnetic induction heating type TOC removing apparatus according to the present invention using the electromagnetic induction coil according to Example 4 under the conditions according to Example 4, the waste liquid having a TOC concentration of 19,000 mgc / liter was subjected to vacuum distillation treatment. The TOC concentration in the obtained distillate was confirmed to be 1 ppm or less, and it was confirmed that pure water was produced. In addition, since this vacuum distillation is performed in a closed system, it is considered that the TOC contained in the waste liquid has moved to the residue.

  The thermal efficiency of the electromagnetic induction heating type TOC removing apparatus according to one embodiment of the present invention was measured by dividing the entire period from start to end into the following five periods.

[Measurement condition]
Waste liquid heating temperature 40 ° C (room temperature 20 ° C → distillation temperature 60 ° C)
Specific heat of waste liquid: 1.0
Waste heat of vaporization: 539.35 cal / g
Capacity of distillation kettle: Length 1500 × φ750
Distilling pot rating: 30-50 liters / h
Heating means: Electromagnetic induction coil unit Maximum output 7 kW x 5 Vacuum degree: -88 to -95 kPa

(1) Start-up: 0-60 minutes 80% operation of all electromagnetic induction coil units, total heater power: 28 kWh
Distillation amount: 26 l / h
Thermal efficiency: 62%

(2) 80% operation-reduced-pressure distillation: 60 to 160 minutes All electromagnetic induction coil units are operated 80%, total heater power: 28 kWh
Distillation amount: 37 l / h
Thermal efficiency: 89%

(3) 100% operation-reduced pressure distillation: 160 to 315 minutes 100% operation of all electromagnetic induction coil units, total heater power: 35 kWh
Distillation amount: 42 l / h
Thermal efficiency: 81%

(4) During first cooking: 315 to 375 minutes Four electromagnetic induction coil units 3a to 3d are operated at 100%, and total heater power is 28 kWh.
Distillation amount: 34 l / h
Thermal efficiency: 81%

(5) During the second cooking: 370 to 395 minutes The three electromagnetic induction coil units 3a to 3c are operated at 80%, and the total heater power is 21 kWh.
Distillation volume: 25 l / h
Thermal efficiency: 79%

  According to the electromagnetic induction heating type TOC removing device according to the present invention, the thermal efficiency at the time of 100% operation of the electromagnetic induction coil unit exceeds 80%, and the oil heater heating type TOC removal according to the comparative example described in the fourth embodiment. It was confirmed that the thermal efficiency was improved by 20% or more compared to the apparatus. In addition to the operation period of (2), at the time of 100% operation of (3), a thermal efficiency of 89% was obtained in the period with the highest thermal efficiency at the moving hour value.

  Furthermore, according to the electromagnetic induction heating type TOC removing apparatus according to the present invention, the first distillate was discharged after 25 minutes from the start of the start, and as much as 26 liters of distillate was generated after 60 minutes from the start. On the other hand, according to the oil heater heating type TOC removing apparatus according to the comparative example, the oil temperature is maintained at a temperature higher than the distillation temperature of 60 ° C. (about 130 ° C.). Cannot be generated. For this reason, in order to produce this 26 liter of distillate, about 28 kWh of power is required. Therefore, it is considered that the overall thermal efficiency of the electromagnetic induction heating type TOC removing apparatus according to the present invention is further superior. Further, during boiling operation, excessive temperature rise prevention and energy saving are achieved by stepping off (turning off) the plurality of electromagnetic induction coil units in stages.

  According to the test using the oil heater heating type TOC removal device that operates on the same principle as the device according to the present invention with respect to the vacuum distillation, the residue produced by the vacuum distillation contains a radioactive substance together with the TOC, In the Japanese Patent Application No. 2008-090796 filed on March 31, 2008 by the present inventors, it has been confirmed that the TOC and radioactive substances are removed from the plant as follows.

[test]
Using the radioactive substance and TOC removal apparatus according to the invention of the above application, according to the radioactive substance and TOC removal method according to one embodiment of the present invention, first, a test for removing radioactive substance and TOC from the radioactive liquid waste is performed as Test 1. The TOC concentration and the radioactive contamination concentration in the distilled water obtained were measured. In addition, as a test 2, in order to confirm whether or not the present treatment method is effective for cleaning agents other than “Chemia Clean”, a removal test of radioactive substances and TOC by waste liquid using a neutral detergent was performed. Test conditions for Tests 1 and 2 are as follows.

・ Radioactive substance and TOC removal device: manufactured by Daiwa Chemical Industry Co., Ltd. as the applicant ・ Processing capacity of distillation still: 8 to 10 l / H
-Pressure in the distillation kettle: 0.090-0.096 MPa (Decompression degree: about -4-10%)
・ Temperature in distillation kettle: 40-60 ° C
-Accompanying filtration means: carbon filter and multi-stage ion exchange resin-Amount of radioactive waste liquid: 300 liters-Radioactive waste liquid-
・ ・ Test 1: Waste liquid after cleaning the tool used in the radiation control area with the decontamination agent “trade name: Chemia Clean” manufactured by Toden Kogyo Co., Ltd.
“Chemia Clean”: Aqueous decontamination of residual water containing 5% total amount of citric acid, malic acid, tartaric acid and formic acid as organic acids. Test 2: Tools used in radiation control areas for general washing Waste liquid after washing with neutral detergent ・ Analysis method ・ TOC (total organic carbon): JIS k0101 20

[Test 1]
The radioactive waste liquid of the test 1 (the waste liquid of the organic acid detergent “Chemia Clean” used for decontamination) is subjected to a removal treatment of radioactive substances and TOC in accordance with the invention and the test conditions according to the application, TOC concentration and radioactive contamination concentration were measured. In this test, calcium hydroxide was added as a neutralizing agent before the vacuum distillation treatment. In case 1, up to vacuum distillation treatment was performed, and in case 2, subsequent to case 1, further filtration treatment was performed. The results of Test 1 are shown in Table 1 below.

（注）：「＜」は、３σ法による検出限界値未満を示す [Table 1]

(Note): "<" indicates less than detection limit value by 3σ method

  Referring to Table 1, radioactive substances are substantially completely removed from the obtained distilled water by the vacuum distillation treatment according to the present invention, and the TOC concentration becomes 10 ppm or less, so that the TOC is reduced to a reusable level. Removed. Moreover, in addition to this vacuum distillation process, the TOC density | concentration in obtained distilled water became 1 ppm or less by performing a filtration process, and TOC was removed to the level of the pure water. In addition, since this removal method and removal apparatus is a completely closed system and the radioactive contamination concentration on the distilled water side is significantly reduced (substantially completely removed), the radioactive substances in the radioactive liquid waste are It can be seen that it remains on the residue side.

[Test 2]
The radioactive waste liquid of Test 2 was subjected to a removal treatment of radioactive substances and TOC in accordance with the invention according to the above application and the above test conditions, and the TOC concentration and the radioactive contamination concentration in the obtained distilled water were measured. In Test 1, since the waste liquid using the organic acid detergent “Chemia Clean” has high acidity and needs to be neutralized, calcium hydroxide is added as a neutralizing agent. Therefore, in Test 2, in order to confirm whether or not this addition of calcium hydroxide has an effect on the removal of radioactive materials and TOC by the vacuum distillation treatment, the test with and without the addition of calcium hydroxide. The effect was also confirmed.

  For this reason, in Case 1, a vacuum distillation treatment is performed, in Case 2, a test in which calcium hydroxide is added (as a neutralizer) before the vacuum distillation treatment in Case 1 is performed, and in Case 3, the vacuum distillation of Case 1 is performed. After the treatment, a filtration treatment was performed. In Case 4, a test was conducted in which calcium hydroxide was added before the vacuum distillation treatment in Case 3. The test results are shown in Table 2 below. The waste liquid before the vacuum distillation treatment was fractionated into about 95% distilled water and about 5% residue (water content 30% or less) by the vacuum distillation treatment.

（注）：「＜」は、３σ法による検出限界値未満を示す
[Table 2]

(Note): "<" indicates less than detection limit value by 3σ method

  Referring to Table 2, as in the case of Test 1, the reduced-pressure distillation treatment according to the present invention removes radioactive substances from the distilled water obtained substantially completely, and the TOC concentration becomes 10 ppm or less. The TOC has been removed to a reusable level. Moreover, in addition to this vacuum distillation process, the TOC density | concentration in obtained distilled water became 1 ppm or less by performing a filtration process, and TOC was removed to the level of the pure water. In addition, since this removal method and removal apparatus is a completely closed system and the radioactive contamination concentration on the distilled water side is significantly reduced (substantially completely removed), the radioactive substances in the radioactive liquid waste are It can be seen that it remains on the residue side.

  In addition, about the influence of calcium hydroxide, both in the state after vacuum distillation treatment and the state where filtration treatment was applied, both in the case where calcium hydroxide is added and in the case where calcium hydroxide is not added, the TOC concentration and the radioactive contamination concentration. There was no substantial difference (somewhat higher when calcium hydroxide was added). Thereby, it was also confirmed that the addition of calcium hydroxide had no influence on the removal of radioactive substances and TOC by the vacuum distillation treatment and on the removal of TOC by the filtration treatment.

  The electromagnetic induction heating type TOC removing apparatus according to the present invention is used for processing a waste liquid containing an organic carbon substance, and is particularly preferably used for a waste liquid treatment in a power plant where energy saving and waste reduction are required. Further, the electromagnetic induction heating type TOC removing apparatus according to the present invention is a radioactive waste liquid generated from a radiation control area of a nuclear power facility, for example, a nuclear power plant, a nuclear fuel reprocessing facility, a radioactive waste disposal facility, in particular, a radioactive contamination tool, etc. It is applied to the treatment of radioactive waste liquid decontaminated with decontamination liquid. In addition, the distillate obtained according to the present invention can be easily treated or reused in a radiation control area or the like. For example, when the distillate is water, it can be treated or reused in an existing water treatment facility. It is.

DESCRIPTION OF SYMBOLS 1 Electromagnetic induction heating type TOC removal apparatus 2 Distilling pot 2a Waste liquid inlet 2b Steam port 3 Electromagnetic induction coil 3a 1st electromagnetic induction coil unit (lower electromagnetic induction coil unit)
3b Second electromagnetic induction coil unit (intermediate electromagnetic induction coil unit)
3c Third electromagnetic induction coil unit (intermediate electromagnetic induction coil unit)
3d Fourth electromagnetic induction coil unit (upper electromagnetic induction coil unit)
3e Fifth electromagnetic induction coil unit (upper electromagnetic induction coil unit)
4 Temperature sensor 4a First temperature sensor (lower temperature sensor)
4b Second temperature sensor (intermediate temperature sensor)
4c Third temperature sensor (intermediate temperature sensor)
4d Fourth temperature sensor (upper temperature sensor)
4e Fifth temperature sensor (upper temperature sensor)
5 Control unit 6 Condenser (heat exchanger)
7 Depressurization pump 8 Buffer tank 9 Residue discharger 11a, 11b Additive tank 12 Waste liquid tank 13 Neutralization tank 14 Residual container 15 Filter 16 IH inverter 17 Feed pump

Claims (6)

An apparatus for removing at least organic carbon substances from waste liquid,
A distillation kettle for distilling the waste liquid under reduced pressure to fractionate the residue containing the organic carbon substance and steam;
An electromagnetic induction coil which is attached to the distillation kettle and heats the waste liquid in the distillation kettle to a temperature at which the distillation kettle can be distilled by electromagnetic induction heating of the distillation kettle itself;
An electromagnetic induction heating type TOC removing device characterized by comprising:   2. The electromagnetic induction heating type TOC removing device according to claim 1, wherein the electromagnetic induction coil is composed of a plurality of electromagnetic induction coil units divided at least in the vertical direction.   The control unit according to claim 2, further comprising a control unit capable of individually controlling on / off of the plurality of electromagnetic induction coil units divided in the vertical direction according to the liquid level of the waste liquid in the distillation pot. Electromagnetic induction heating TOC removal device. The electromagnetic induction coil is composed of a plurality of electromagnetic induction coil units divided at least in the vertical direction,
A temperature sensor for detecting the temperature of the distillation kettle;
Based on temperature detection by the temperature sensor, a control unit capable of individually controlling on / off of the plurality of electromagnetic induction coil units divided in the vertical direction;
The electromagnetic induction heating type TOC removing device according to claim 1, wherein The temperature sensor is composed of a plurality of temperature sensors respectively attached to the plurality of electromagnetic induction coil units,
5. The electromagnetic induction heating type TOC according to claim 4, wherein each of the temperature sensors is capable of detecting a partial temperature of the distillation pot near the electromagnetic induction coil unit to which the temperature sensor is attached. Removal device.   6. The electromagnetic induction heating type TOC removing device according to claim 5, wherein waste liquid is additionally supplied to the distillation kettle according to partial temperatures of the distillation kettle detected by the plurality of temperature sensors.

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