JP2008000716A - Vacuum heating apparatus equipped with back-flow prevention tank for preventing backflow of oil-scrubber cleaning oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum heat-treatment apparatus capable of solving problems arising upon treating waste contaminated with a halogenated organic compound such as PCB by a combination of a cleaning treatment using an organic solvent and a vacuum heat-treatment. <P>SOLUTION: The vacuum heat-treatment apparatus for treating contaminated waste having been roughly cleaned using an organic solvent is comprised of a back-flow prevention tank disposed in an exhaust flow path that connects a vacuum heating furnace and an oil scrubber with one end of an exhaust inflow pipe disposed in the upper part of the tank and one end of an exhaust outflow pipe disposed in the bottom part of the tank. By virtue of the above structure, the cleaning oil can be prevented from flowing back to the vacuum heating furnace even if it is made to bubble and to flow backward in the exhaust flow path by a large amount of the vaporized organic solvent flowing from the vacuum heating furnace into the oil scrubber. In addition, the cleaning oil that has flowed backward can be spontaneously recovered into the oil scrubber. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heat treatment apparatus for heat-treating and detoxifying contaminated waste that is contaminated with fat-soluble pollutants such as PCB (Polychlorinated biphenyl) and washed with an organic solvent.

  PCBs have been widely used as electrical insulators in the past because they are very stable both chemically and thermally and have excellent electrical insulation properties. However, since it is a carcinogenic harmful substance that is not decomposed even after being disposed of and easily accumulates in the human body, its manufacture and import etc. were prohibited in 1974.

  Although manufacturing, importing, etc. were prohibited, there was no appropriate disposal technology for PCBs, so waste containing PCBs was obliged to be stored by the user until the official disposal method was determined after use. However, in Japan, public disposal standards and treatment facilities for PCBs and PCB-containing waste have not been established for about 30 years, and this is a heavy burden on users. For this reason, establishment of a method for treating PCBs and wastes containing PCBs is expected.

  As a method for treating PCB itself, a dechlorination decomposition method, a hydrothermal oxidation decomposition method, a reduction thermochemical decomposition method, and the like are known. On the other hand, as a method for treating contaminants contaminated by PCB, a solvent cleaning method, a recovery method by vacuum heating, and the like are known.

As a technique for solvent cleaning methods, by immersing the object to be processed in the cleaning liquid during consisting alcohols or chlorinated of C ₁ -C _4, a method of cleaning the PCB attached to minute gaps of the workpiece surface, patent It is disclosed in Document 1.

  In addition, as a technique for PCB recovery by vacuum heating, the insulating oil is previously extracted from the transformer member using the PCB-containing insulating oil, and then the transformer member is placed in a vacuum heating furnace to heat and depressurize the PCB and insulating oil. Patent Document 2 discloses a method characterized by evaporating and removing from a transformer member and using the transformer member as a valuable material.

Further, Patent Document 3 discloses a processing system that decomposes an organic halide such as PCB and that processes exhaust gas discharged from a vacuum heating furnace using a hydrothermal decomposition processing facility. Patent Document 3 also discloses that exhaust gas discharged from a vacuum heating furnace is cooled by a cooling means, and the cooled gas is processed by a hydrothermal decomposition treatment facility.
Japanese Patent Laid-Open No. 2003-24885 JP-A-9-192534 JP 2003-62428 A

  Among organic chlorinated compounds, PCB has low volatility, and as shown in Patent Document 2, if it is not heated under reduced pressure using a vacuum heating furnace, it can be recovered from waste such as transformer members by evaporation. Can not. For this reason, if there is a large amount of PCB remaining in the waste, it takes a long time to recover. However, it is difficult to predict the amount of PCB remaining in the waste, and the processing may be insufficient.

  On the other hand, the solvent cleaning method disclosed in Patent Document 1 has an advantage that the waste can be cleaned regardless of the amount of PCB remaining in the waste. However, in order to completely remove the PCB from the waste, it is necessary to repeat the cleaning with the cleaning solution over and over, resulting in a large amount of waste cleaning solution. Furthermore, if the waste has a complicated structure and it is difficult for the cleaning liquid to reach the inside, there is also a problem that PCB tends to remain in the waste after treatment compared to a treatment method that collects by vacuum heating. .

  Therefore, waste contaminated with PCB or the like is first washed with an organic solvent, and then heat-treated using a general vacuum heating apparatus composed of a vacuum heating furnace, a wet scrubber, etc. It is conceivable to compensate for the shortcomings of the technology.

  In this case, it is not possible to predict the amount of PCB and organic solvent generated from the object to be treated (cleaned waste waste) during the vacuum heat treatment, so it is necessary to increase the oil scrubber, and the amount of cleaning oil to be used increases. . Moreover, the vacuum pump to be used must be increased in size, and the equipment cost and operation cost increase.

  On the contrary, if the oil scrubber is small, the exhaust gas is not sufficiently cooled and condensed, and the PCB is exhausted from the oil scrubber in a gas or mist state. Even if an activated carbon adsorption device is installed in the exhaust path of the oil scrubber, it is necessary to frequently replace the activated carbon.

  Furthermore, if the amount of organic solvent remaining in the object to be treated (cleaned contaminated waste) is large, the organic solvent gas discharged from the vacuum heating furnace is cooled by an oil scrubber to become a liquid, and is once dissolved in the cleaning oil. However, since the inside of the oil scrubber has a negative pressure, the organic solvent dissolved in the cleaning oil immediately evaporates, and the cleaning oil is bubbled.

  Then, the cleaning oil that is foam may flow backward in the exhaust gas path connected from the vacuum heating furnace to the oil scrubber and reach the vacuum heating furnace. The oil scrubber cleaning oil has very low volatility, and thus does not evaporate in the vacuum heating furnace and accumulates in the furnace. In such a case, it is necessary to stop the entire heat treatment apparatus and clean the inside of the vacuum heating furnace.

  If the cleaning oil is foamed in the oil scrubber, it is possible to prevent backflow of the cleaning oil by temporarily removing a part of the cleaning oil from the bottom. In reality, it is very difficult to pull out the cleaning oil in the state of

  The present invention provides a vacuum heat treatment apparatus that solves the above-mentioned problems that occur when waste contaminated with an organic chlorine-based compound such as PCB is used in combination with a cleaning treatment using an organic solvent and a vacuum heat treatment. The purpose is to do.

  The present invention relates to a cleaned contaminated waste heat treatment apparatus that heat-treats contaminated waste washed with an organic solvent under reduced pressure, and a backflow prevention tank to an exhaust gas path connecting a vacuum heating furnace and an oil scrubber By solving this problem, the above problems were solved.

Specifically, the present invention
A cleaned contaminated waste heat treatment apparatus that heats a contaminated waste washed with an organic solvent under reduced pressure heating,
A vacuum furnace,
An oil scrubber for cleaning the exhaust gas from the vacuum heating furnace;
A vacuum pump installed in the exhaust passage of the oil scrubber;
With a backflow prevention tank installed in the exhaust gas path connecting the vacuum heating furnace and the oil scrubber,
An exhaust gas inflow side pipe end of the backflow prevention tank is arranged at the upper part of the tank, and an exhaust gas outflow side pipe end is arranged at the tank bottom (Claim 1).

  By installing a backflow prevention tank in the exhaust gas path that connects the exhaust gas outlet of the vacuum heating furnace and the oil scrubber, even if the cleaning oil is foamed in the oil scrubber, the cleaning oil only accumulates in the backflow prevention tank. Cleaning oil does not enter the vacuum furnace.

  In addition, unlike normal traps, the cleaning oil accumulated in the backflow prevention tank is returned to the oil scrubber without using a special device when the pressure is restored or when the vacuum heating device is decompressed again.

  Examples of the contaminated waste include PCB-contaminated waste (Claim 2). The vacuum heat treatment apparatus of the present invention is suitable as a PCB treatment apparatus that requires appropriate disposal because of its low volatility and strong toxicity among organochlorine compounds.

  The organic solvent may be a normal paraffinic organic solvent.

  Normal paraffinic organic solvents such as normal pentane and normal hexane are suitable for cleaning contaminated waste because they easily dissolve organochlorine compounds such as PCB, have point viscosity, and are inexpensive. Further, since the boiling point is low and the volatility is high, when the organic solvent is volatilized by the heat treatment under reduced pressure, a part of the organic chlorine compound is volatilized, so that the detergency is improved during the heat treatment under reduced pressure.

  On the other hand, however, if heat treatment under reduced pressure is carried out with a large amount of organic solvent remaining in the contaminated waste, the normal paraffinic organic solvent that is volatilized by pressure reduction and heating and once dissolved in the cleaning oil by cooling with an oil scrubber is obtained. Further, the vacuum furnace and the oil scrubber are further depressurized, so that they are rapidly vaporized even at a low temperature of about 50 ° C., and the cleaning oil is easily foamed.

  As the cleaning oil for the oil scrubber, it is preferable to use a hydrocarbon oil having a vapor pressure at 10 ° C. of less than 500 Pa and a boiling point of 300 ° C. or more.

  The oil scrubber is preferably operated at 20 ° C. or less, particularly preferably 10 ° C. or less, for collecting organochlorine compounds such as PCB discharged from the heating furnace. Therefore, when the cleaning oil used in the oil scrubber has a vapor pressure at 10 ° C. of less than 500 Pa, the cleaning oil can be prevented from volatilizing and coming out of the oil scrubber together with the exhaust gas.

  In addition, if the boiling point is 300 ° C or higher, the organic chlorine collected by the oil scrubber is easy to separate when the organic chlorinated compounds such as PCB collected by the oil scrubber and the washing oil are separated by distillation under reduced pressure. In detoxifying the compound, the amount of cleaning oil to be treated can be reduced by performing distillation under reduced pressure. An example of such a cleaning oil is barrel processing oil.

  The internal volume of the backflow prevention tank below the exhaust gas inflow side pipe end is preferably 5% by volume to 40% by volume of the cleaning oil stored in the bottom of the oil scrubber during operation (Claim 5).

  Backflow in the exhaust gas path is limited to cleaning oil or the like stored at the bottom of the oil scrubber, and since it is in a foamed state when backflowing, it is not necessary to be able to store all of the cleaning oil used in the oil scrubber . It is only necessary to store 5% to 40% by volume, more preferably 10% to 30% by volume, of the cleaning oil stored at the bottom of the oil scrubber below the end of the exhaust gas inflow side pipe.

  It is preferable that an activated carbon adsorption device is provided in the exhaust path.

  This is because a small amount of organic chlorine compound, organic solvent and / or cleaning oil exhausted from the oil scrubber is adsorbed to prevent discharge from the system.

  The contaminated waste heat treatment apparatus of the present invention can prevent the oil scrubber cleaning oil from flowing back into the vacuum heating furnace by including a backflow prevention tank having a very simple structure. In addition, the cleaning oil that has flowed back by normal operation can be returned to the oil scrubber.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. The present invention is not limited to these.

  An example of the basic configuration of the contaminated waste heat treatment apparatus of the present invention is shown in FIG. The contaminated waste heat treatment apparatus shown in FIG. 1 includes a vacuum heating furnace 1, a backflow prevention tank 3, an oil scrubber 5, a vacuum pump 11, and an activated carbon adsorption tower 12 (activated carbon adsorption apparatus).

  In order to reduce the load on the activated carbon adsorption tower, a cooling condenser is provided after the vacuum pump, and the exhaust gas after the organochlorine compound such as PCB is removed by the oil scrubber 5 is cooled to 10 ° C. or lower. Therefore, it is preferable that the cleaning oil remaining in the exhaust gas, a small amount of PCB, and the like are separated and removed.

  The exhaust port of the vacuum heating furnace 1 is connected to the backflow prevention tank 3 by the exhaust gas path 2. The backflow prevention tank 3 is connected to an oil scrubber 5 by an exhaust gas path 4. The vacuum heating furnace 1, the backflow prevention tank 3, and the oil scrubber 5 each have an airtight structure.

  The oil scrubber 5 is provided with a shower 6 at the top, and sprays cleaning oil 7 inside. The sprayed cleaning oil 7 absorbs the organic solvent and the organic chlorine compounds such as PCB in the exhaust gas supplied to the oil scrubber 5 from the vacuum heating furnace 1 through the backflow prevention tank 3 and cools the exhaust gas. The cleaning oil 7 stored at the bottom is supplied again to the shower 6 by the oil pump 9 installed in the circulation path 8.

  It is preferable that the cleaning oil 7 used for a certain period is discharged from the waste oil passage 14 when the operation is stopped or when the pressure is reduced as described later, and is separately processed. Further, a cooling device for the cleaning oil 7 may be installed in the circulation path 8 so that the cleaning oil is cooled to 50 ° C. or lower, preferably 10 ° C. or lower.

  An exhaust passage 10 is connected to the uppermost part of the oil scrubber 7. A vacuum pump 11 and an activated carbon adsorption device 12 are installed in the exhaust path 10. When the inside of the vacuum heating furnace 1 is heated to a certain temperature and the vacuum pump 11 is operated, the air in the vacuum heating furnace 1, the backflow prevention tank 3 and the oil scrubber 5 is exhausted outside the system through the exhaust path 10, and the vacuum heating device The inside is decompressed. When the inside of the vacuum heating apparatus 1 is further heated in this state, the organic chlorine-based compound such as PCB and the organic solvent remaining in the object to be treated (cleaned contaminated waste) are evaporated and separated from the object to be treated.

  If a cooling condenser (not shown) is installed at the rear stage of the vacuum pump 11, a trace amount of the organic chlorine compound and the organic solvent contained in the gas discharged from the oil scrubber 5 are cooled by the cooling condenser, and are discharged from the exhaust gas. It can be separated and removed.

  Further, even when gaseous organic chlorine compounds and / or organic solvents are discharged from the cooling condenser, they are removed by the activated carbon adsorbing device 12 and therefore discharged from the exhaust outlet 13 to the outside of the system. Can be prevented.

  Containers and equipment to be treated (waste) contaminated with organic chlorinated compounds such as PCB should be washed with an organic solvent such as normal hexane after the PCB is removed and disassembled as a pretreatment. The extracted organic chlorinated compounds such as PCB are separately subjected to decomposition treatment and the like. The organic solvent used for washing is preferably reused after separating an organic chlorine-based compound such as PCB and the organic solvent by distillation or the like.

  Examples of the cleaning method include immersion cleaning in which an object to be processed is immersed in an organic solvent such as normal hexane, and ultrasonic cleaning in which ultrasonic waves are combined with this. When the surface of the object to be processed is smooth and flat, the surface may be wiped with a cloth soaked with an organic solvent.

  The object to be processed is preferably an electric device such as a transformer or a capacitor.

  Next, the operation of the waste heat treatment apparatus of the present invention will be described by taking the processing of a capacitor using PCB as an example, and the function of the backflow prevention tank will be described in comparison with a normal trap.

  First, as pretreatment, the PCB oil in the capacitor is drained, the lid of the capacitor after draining is cut, the internal components (for example, elements) are taken out, and the capacitor container is washed with an organic solvent. Further, the internal parts are disassembled, cut, put into a container, washed with an organic solvent, and a part of the organic solvent is removed from the object to be processed. Since the container that is not impregnated with PCB is easy to clean, it may be cleaned only with an organic solvent as described above, but it is not limited to this. May be performed.

  Then, the vacuum heating furnace 1 is sealed, and the air in the vacuum heating furnace is replaced with an inert gas (for example, nitrogen gas). As a replacement method, for example, the vacuum pump 11 and the oil scrubber 5 may be operated, and the inert gas may be supplied into the vacuum heating furnace 1 from the return pressure path 16.

  At this time, the vacuum pump 11 is not necessarily operated, and it is sufficient if the air in the vacuum heating furnace 1 can be replaced with an inert gas.

  After the inside of the vacuum heating furnace 1 is sufficiently replaced with an inert gas, the inside of the vacuum heating furnace 1 is heated to 200 to 250 ° C. When the temperature of the object to be processed in the vacuum heating furnace 1 reaches 130 to 160 ° C., the vacuum pump 11 is operated, and the air inside the apparatus is exhausted to a reduced pressure state.

  The pressure inside the apparatus (including the vacuum heating furnace 1) is 10 Pa or more and 1000 Pa, preferably 50 Pa or more and 200 Pa or less, and the temperature of the workpiece in the vacuum heating furnace 1 is preferably 170 ° C. or more and 200 ° C. or less.

  In the vacuum heating furnace 1, an organic chlorine compound such as PCB and an organic solvent are vaporized from an object to be treated (cleaned contaminated waste) and exhausted from an exhaust gas outlet to an exhaust path 2. Further, the exhaust gas from the vacuum heating furnace 1 is supplied to the oil scrubber 5 through the backflow prevention tank 3. Here, the organic chlorine-based compound and the organic solvent in a gaseous state are absorbed by the cleaning oil 21 sprayed from the shower 6 or are aggregated and collected.

  Here, when a large amount of the organic solvent remains in the object to be processed put into the vacuum heating furnace 1, the gaseous organic solvent is condensed in the oil scrubber 5 by cooling with the cleaning oil 7, and the cleaning oil 7 once dissolved (see FIG. 2 (a)). However, since the oil scrubber 5 is depressurized, if the oil scrubber 5 is depressurized to a certain value or less, the organic solvent immediately vaporizes and causes the cleaning oil 7 to be bubbled (FIG. 2 (b). )). Then, the foamed cleaning oil 23 flows backward from the end of the exhaust gas path 4 toward the backflow prevention tank (see FIG. 2 (c)).

  An exhaust gas path 2 and an exhaust gas path 4 are connected to the backflow prevention tank 3, but as shown in FIG. 1, the end a of the piping on the vacuum heating furnace 1 side (exhaust gas inflow side piping) is at the upper part of the tank. The end b of the pipe on the oil scrubber 5 side (exhaust gas outflow side pipe) is arranged at the bottom of the tank.

  Therefore, as shown in FIG. 3 (a), the cleaning oil that has flowed back from the oil scrubber 5 into the exhaust gas path 4 enters the backflow prevention tank 3 from the end of the exhaust gas outlet pipe 33 and is stored therein. The However, since the end a of the exhaust gas inflow side pipe 32 connected to the vacuum heating furnace 1 is arranged at the upper part of the tank, the cleaning oil 31 that has flowed backward flows from the end a of the exhaust gas inflow side pipe 32 to the exhaust path 2. And does not flow back into the vacuum heating furnace 1.

  If the bubbling of the cleaning oil is settled in the oil scrubber 5, the cleaning oil 31 that has flowed backward flows from the end b of the exhaust gas outlet side pipe 33 to the oil scrubber 5 through the exhaust gas path 4 by the suction force of the vacuum pump 11. Returned autonomously.

  Further, even when only a part of the backwashed cleaning oil 31 can be returned to the oil scrubber 5 during operation due to the suction force of the vacuum pump 11, after the operation is completed, the return pressure path 16 from the inert gas supply device 15. In order to supply the inert gas to the vacuum heating furnace 1 and restore the pressure, the cleaning oil 31 that has flowed back from the exhaust gas inflow side pipe 32 is almost exhausted from the end b of the exhaust gas outflow side pipe 33 by the pressure of the inert gas entering from the exhaust gas inflow side pipe 32. It is possible to return autonomously to the oil scrubber 5 via the route 4.

  In particular, when PCB is efficiently removed using the vacuum heating furnace 1, it is preferable not only to heat under reduced pressure, but also to repeatedly reduce and return pressure under heating. This is because, as the inert gas moves when the decompressed vacuum heating furnace 1 is depressurized, the PCB adhering to the vacuum heating furnace 1 or the object to be processed moves accompanying the inert gas. This is because the PCB can be effectively removed.

  As described above, even when the pressure reduction and the return pressure are repeated, the cleaning oil that has been foamed at the time of the pressure reduction and returned to the backflow prevention tank 3 can be returned to the oil scrubber 5 by the pressure of the inert gas at the time of the return pressure. Foaming can be prevented by removing a part of the cleaning oil through the waste oil path 14 before the depressurization step, and it is possible to prevent the cleaning oil from flowing back in large quantities even if foaming occurs.

  The cleaning oil taken out from the waste oil path 14 can be separated into an organic solvent, PCB oil and cleaning oil by distillation. The separated PCB oil is separately decomposed, and the organic solvent and the cleaning oil are reused.

  Further, it is preferable to add new cleaning oil from a cleaning oil supply path (not shown) as necessary. Thereby, the organic solvent concentration in the cleaning oil in the oil scrubber 5 can be reduced, and foaming can be suppressed.

  The inert gas is not limited as long as it is nitrogen, helium, argon, or the like. Moreover, the inert gas supply apparatus 15 is a gas cylinder, for example. When the inert gas is nitrogen, a PSA (Pressure Swing Adsorption) nitrogen generator or a membrane nitrogen generator may be used as the inert gas supply device.

  Since the entire amount of the cleaning oil in the oil scrubber 5 cannot flow back to the exhaust gas path 4, the internal volume of the backflow prevention tank 3 is from the end a of the exhaust gas inflow side pipe 32 to the oil scrubber. 5 vol% or more and 40 vol% or less, preferably 10 vol% or more and 30 vol% or less of the volume of the cleaning oil stored at the bottom of 5 (portion denoted by 7a in FIG. 2 (a)) It is more preferable. This is because if the internal volume is less than 5% by volume, the storage capacity of the backwashing cleaning oil is insufficient and the backflow to the vacuum heating furnace 1 may not be prevented, and if it exceeds 40% by volume, it is stored by the action of the vacuum pump 11. This is because it becomes difficult to return the washed cleaning oil to the oil scrubber.

  3 (a) and 3 (b) show an example in which the end a of the exhaust gas inflow side pipe 32 is located below the ceiling surface of the backflow prevention tank 3, but the exhaust gas inflow side pipe 32 The end a may coincide with the ceiling surface of the backflow prevention tank 3. Further, the backflow prevention tank 3 may be configured to be heated from the outside in order to prevent the organic solvent and PCB contained in the exhaust gas from the heating furnace 1 from condensing inside.

  On the other hand, a trap usually installed in an exhaust gas path of a conventional waste heat treatment apparatus has a structure as shown in FIG. 4 (a) (see, for example, FIG. 2 of JP-A-2003-299903). ). That is, the exhaust gas path 2 and the exhaust gas path 4 are connected to the trap 41 in the same manner as the backflow prevention tank 3, but the end c of the piping on the vacuum heating furnace 1 side (exhaust gas inflow side piping 42) is arranged at the bottom of the tank. The end d of the pipe on the oil scrubber 5 side (exhaust gas outflow side pipe 43) is arranged in the upper part of the tank.

  In the trap 41, when a large amount of organic solvent flows from the vacuum heating furnace 1 in the initial stage of operation in a state where the liquid and the gas are mixed, the liquid organic solvent can be stored in the trap 41. Further, since the end d of the exhaust gas outflow side pipe 43 is arranged at the upper part of the tank, the stored organic solvent 44 does not move to the oil scrubber 5 through the exhaust gas path 4 (see FIG. 2 (a)). For this reason, the trap 41 can reduce foaming of the cleaning oil of the oil scrubber 5 due to mixing of a large amount of the organic solvent.

  However, when a large amount of organic solvent flows into the trap 41 in a gaseous state, the organic solvent passes through the trap 41 and is supplied to the oil scrubber 5. Then, the oil is cooled and condensed in the oil scrubber 5, causing the cleaning oil to bubble as described above, and the cleaning oil 45 that has flowed back is stored in the trap 41 through the exhaust gas path 4.

  However, if an abrupt reverse flow occurs in the trap 41, the end c of the exhaust gas inflow side pipe 42 is disposed at the bottom of the trap 41, so that the cleaning oil stored in the trap 41 is discharged from the exhaust gas inflow side pipe. There is a risk that the gas is pushed up from the end c of the gas 42 to the exhaust gas path 2 and further flows back to the vacuum heating furnace 1 (see FIG. 4B).

  Even if the backflow of the cleaning oil to the trap 41 is settled, the backflow of cleaning oil 45 cannot be returned to the oil scrubber 5 because the end of the exhaust gas outflow side pipe 43 is disposed at the upper part ( (See FIG. 4 (c)). For this reason, the cleaning oil 45 that has flowed back has to be extracted from the bottom of the trap 41.

  As described above, the contaminated waste heat treatment apparatus of the present invention includes a backflow prevention tank having a very simple structure, thereby preventing the backflow of cleaning oil to the vacuum heating furnace and autonomous recovery of the backwashed cleaning oil. It has a unique effect that cannot be obtained with the contaminated waste heat treatment apparatus.

  In this embodiment, in order to increase the heating efficiency, the inside of the vacuum heating furnace 1 is filled with an inert gas, the inside of the vacuum heating furnace is heated, and then heated while reducing the pressure. It is not limited, You may operate | move so that it may reduce pressure simultaneously with a heating, or may heat after a pressure reduction.

  The contaminated waste heat treatment apparatus of the present invention is useful in the environmental conservation field and the waste treatment field for the purpose of detoxifying a waste contaminated with an organic chlorine-based compound such as PCB.

It is a block diagram which shows an example of the contaminated waste heat processing apparatus of this invention. It is a conceptual diagram explaining foaming and backflow of cleaning oil in the oil scrubber. It is a figure explaining a movement of cleaning oil in a backflow prevention tank. It is a figure explaining a motion of cleaning oil in a trap.

Explanation of symbols

1: Vacuum heating furnace 2: Exhaust gas path (upstream of backflow prevention tank)
3: Backflow prevention tank 4: Exhaust gas path (downstream of backflow prevention tank)
5: Oil scrubber 6: Shower 7: Cleaning oil 8: Circulation path 9: Oil pump 10: Exhaust path 11: Vacuum pump 12: Activated carbon adsorption device 13: Exhaust outlet 14: Waste oil path 15: Inert gas supply device 16: Recovery Pressure path 21: Sprayed cleaning oil 22: Condensed organic solvent 23: Foamed cleaning oil 31: Backwashing cleaning oil 32, 42: Exhaust gas inflow side piping 33, 43: Exhaust gas outflow side piping 41: Trap 44: Retained Organic solvent 45: Backflow cleaning oil a: End portion of exhaust gas inflow side piping of backflow prevention tank b: End portion of exhaust gas outflow side piping of backflow prevention tank c: End portion of exhaust gas inflow side piping of trap d: Trap end End of exhaust gas outlet side piping

Claims (6)

A cleaned contaminated waste heat treatment device that heats a contaminated waste washed with an organic solvent under reduced pressure,
A vacuum furnace,
An oil scrubber for cleaning the exhaust gas from the vacuum heating furnace;
A vacuum pump installed in the exhaust passage of the oil scrubber;
With a backflow prevention tank installed in the exhaust gas path connecting the vacuum heating furnace and the oil scrubber,
An exhaust gas inflow side pipe end of the backflow prevention tank is arranged at the upper part of the tank, and an exhaust gas outflow side pipe end is arranged at the tank bottom.   The heat treatment apparatus according to claim 1, wherein the contaminated waste is a PCB contaminated waste.   The heat treatment apparatus according to claim 1, wherein the organic solvent is a normal paraffin organic solvent.   The heat treatment apparatus according to any one of claims 1 to 3, wherein the cleaning oil used in the oil scrubber is a hydrocarbon oil having a vapor pressure of less than 500 Pa at 10 ° C and a boiling point of 300 ° C or higher. .   5. The internal volume below the exhaust gas inflow side pipe end of the backflow prevention tank is 5 vol% or more and 40 vol% or less of the cleaning oil stored at the bottom of the oil scrubber during operation. The heat processing apparatus as described in. The heat treatment apparatus according to claim 1, further comprising an activated carbon adsorption device in the exhaust path.

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