JP2013081570A - Pcb detoxification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PCB detoxification method for continuously detoxifying PCB with high efficiency.SOLUTION: A mixed liquid containing a PCB liquid and kerosene of 10:90 to 80:20 in weight ratio, and a processing liquid in which metal sodium having the same equivalent weight as that of chlorine in PCB and having an average grain size of 1-3 μm is suspended and distributed are supplied to a processing chamber 1 having a fixed circular body 20 and a rotating disc 10, while supplying an inert gas 4 into the processing chamber 1 from the bottom. The rotating disc 10 is rotated at 10,000 to 18,000 rpm, and is increased in temperature to 150 to 250°C.

Description

  The present invention relates to a method for detoxifying polychlorinated biphenyl (hereinafter referred to as PCB) using physical and mechanical means.

PCB is widely used as an electrical insulating oil because it is a chemically stable substance and excellent in insulation.
However, while it has become clear that PCBs have an adverse effect on the human body, the residual PCB has become a social problem because it remains persistent for a long time due to its indegradability, and the human body has been adversely affected. It is known around.

  Conventionally, as a treatment method for detoxifying the problem substance PCB, treatment methods such as a dechlorination decomposition method, a hydrothermal oxidative decomposition method, a photolysis method, and a plasma decomposition method are used. It is known that it was proposed as

  However, the above-mentioned proposed method requires a reaction vessel having pressure resistance and heat resistance because the inside of the sealed pressure vessel is subjected to PCB treatment at high temperature and high pressure or in the presence of nitrogen gas. . For this reason, there is a problem that the equipment cost is bulky and the production of the reaction vessel is not easy, and there is a practical problem that a large amount of PCB cannot be continuously treated due to the treatment in the sealed pressure vessel. .

  In view of the problems of the proposed technique, the inventor of the present invention previously proposed a PCB detoxification method that does not require a sealed pressure vessel according to Patent Documents 1 and 2 and the like.

  The PCB detoxification method proposed by the inventor of the present application uses the mechanochemical effect due to the action of a high-speed rotating disk with a small hole. Therefore, there remains a problem to be solved about the processing mode for obtaining the desired processing effect.

JP 2001-179084 A JP 2002-136857 A

  Therefore, in the present invention, a PCB detoxification method that can efficiently and continuously perform the detoxification process when detoxifying the PCB using the mechanochemical effect of the high-speed rotating disk with small holes is provided. The issue is to provide.

The configuration of the PCB detoxification processing method of the present application made for the purpose of solving the above problems is as follows.
At the center of the processing chamber, a plurality of rotating disks having a diameter of 250 mm to 350 mm having a plurality of through holes in the surface are arranged attached to the rotating shaft, and the rotating disks are fixed so as to sandwich the rotating disks from above and below. In rotating the rotating disk at a high speed between fixed annular bodies in a processing chamber having a configuration in which the body is provided on the inner peripheral wall surface of the chamber,
While supplying an inert gas into the processing chamber, the PCB liquid to be processed and kerosene are mixed at a weight ratio of 10:90 to 80:20, and the mixed liquid is heated to 100 ° C. to 150 ° C. A treatment liquid in which metallic sodium having an average particle diameter of 1 μm to 3 μm, which is equivalent to chlorine in PCB, is suspended and dispersed is supplied into the chamber from the bottom side, while the rotating disk is supplied at 10,000 rpm to 18, By rotating at 000 rpm,
The surface of the stationary annular body, the plane of the rotating disk, and the holes act to turbulently flow the gas in the chamber and the treatment liquid supplied to cause ultrasonic vibrations,
At the same time, the processing liquid in the chamber is heated to 150 ° C. or higher and 250 ° C. or lower by the action of the stationary annular body holding the gas and the processing liquid in the gap and the rotating disk, and the processing liquid is charged with 20,000 G˜ Apply 40,000G acceleration,
The chlorine of the PCB separated by cutting the intermolecular bond of the treatment liquid and the metal sodium are combined, and the treated liquid containing biphenyl and sodium chloride produced thereby is discharged from the discharge part at the top of the chamber. It is characterized by that.

  In the present invention, when the rotating disk is rotated at an ultra high speed of 10,000 to 18,000 rpm in the processing chamber, the inert gas is supplied into the processing chamber and the PCB liquid and kerosene to be processed are in a weight ratio. Mix in a ratio of 10:90 to 80:20, add metallic sodium heated to 100 ° C to 150 ° C equivalent to chlorine in PCB, and float metallic sodium with an average particle size of 1 µm to 3 µm The processing liquid mixed so as to be dispersed is supplied from the bottom side into the chamber from the bottom, and the processing liquid is turbulent to generate ultrasonic vibration, and the processing liquid in the chamber is 150 ° C. or higher. While increasing the temperature to 250 ° C. or less, an acceleration of 20,000 G to 40,000 G is applied to the treatment liquid, and thereby the PCB separated by breaking the intermolecular bond of the treatment liquid. The treated liquid containing biphenyl and sodium chloride can be discharged from the discharge unit at the top of the chamber. Thus, even a large amount of PCB can be detoxified efficiently and continuously. Further, since the processing chamber does not have to be a sealed pressure vessel, the equipment cost is low and the manufacturing is easy.

The systematic diagram of an example for implementing this invention PCB detoxification processing method. The longitudinal cross-sectional view which showed typically an example of the structure of the processing chamber in the processing system | strain of FIG.

Next, an embodiment of the method of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a processing chamber, and 2 denotes a temporary storage of a 100 ° C. to 150 ° C. processing liquid in a state where PCB to be processed is mixed with kerosene so that the processing liquid can be supplied to the chamber 1 in a predetermined manner. 3 is a sodium addition device for adding metallic sodium melted at 100 ° C. to 150 ° C. to the treatment liquid sent from the storage tank 2. In the mixer, the sodium is suspended and dispersed in the treatment liquid with an average particle diameter of 1 μm to 3 μm. The processing solution in which metallic sodium is suspended and dispersed is supplied to the processing chamber 1 at a feed rate of 2 l / min to 6 l / min, for example, a feed rate of about 4 l / min. Into the chamber. In FIG. 1, V1 to V3 are valves inserted between the storage tank 2 and the processing chamber 1, and P is also a pump.

  A configuration example of the processing chamber 1 will be described in detail later with reference to FIG. 2, but it is continuously fed by the feed amount into the inside of the chamber 1 filled with nitrogen from the outlet 4N by the action of the nitrogen supply means 4. The processing solution is 3 to 4 pieces rotating at about 12,000 rpm as an example within the chamber, 4 pieces as an example, a rotating disk having a small hole and a diameter of 250 mm to 350 mm as an example 300 mm 10 and the rotating disk 10 are subjected to a so-called mechanochemical action by the action of the non-rotating fixed plate 20 provided on the inner peripheral wall surface of the chamber.

  The treatment liquid containing PCB subjected to the above action is a treated liquid containing biphenyl in which molecular bonds between PCB chlorine and biphenyl are cleaved, and the separated chlorine is combined with the metal sodium to form sodium chloride. The liquid is sent out of the chamber by the centrifugal force of the high-speed rotating disk 10 acting on the processing liquid from the upper part 1b of the chamber 1, so that the PCB contained in the processing liquid is rendered harmless.

In FIG. 1, 5 is a condenser that cools the processed liquid delivered from the upper part 1b of the processing chamber 1, and 6 is a processed tank that stores the processed liquid that has passed through the condenser. Incidentally, the temperature of the processed liquid processed and sent out from the processing chamber 1 and entering the condenser 5 is around 180 ° C.
In the present invention, the processed liquid that enters the primary processed tank 6 has its PCB concentration measured by the concentration measuring means 10 and includes a PCB that is not harmed by the processed liquid according to the measurement result. 11, a recirculation type reprocessing route that returns to the storage tank 1 using the return pump 7 and is sent to the processing chamber 1 again is provided. Reference numeral 61 denotes a processing completion tank to which the processed liquid determined by the determination unit 11 as not containing PCB is supplied via the switching unit 12. In the discriminating unit 11, a signal for switching the flow path of the switching unit 12 and a signal for starting and stopping the return pump 7 are formed based on the signal from the measuring means 10, and the signal is sent to the switching unit 12 and the return pump 7. It comes to be supplied.

  Reference numeral 8 denotes a vapor condenser that cools and condenses the vapor / gas generated during the treatment in the processing chamber 1, and the vapor / gas cooled and condensed by the condenser 8 includes a filtering material 9 a such as activated carbon. Then, it is fed to the primary treated tank 6 through the filtration tank 9.

Next, an example of a specific structure of the processing chamber used in the present invention will be described with reference to FIG.
In FIG. 2, the processing chamber 1 has the following configuration. That is, the processing chamber 1 preferably has a cylindrical inner chamber 30 with an uneven inner peripheral wall, and a thick rotating shaft 40 extending upward from the chamber 1 is rotatably provided at the center of the inner chamber 30. ing. In the rotating shaft 40, a cooling passage for circulating a liquid coolant in the center is formed by a hole 40a provided in the rotating shaft 40 and a supply pipe 40b of the coolant CL inserted in the hole 40a. The illustrated rotating shaft 40 includes a cooling mechanism above the chamber 1 and is supported by lower bearings 40c and 40d. The positions of the bearings 40c and 40d are not limited to the illustrated example.

The outer peripheral surface of the processing chamber 1 is almost entirely covered with an outer chamber jacket 50, and steam / gas generated in the inner chamber 30 of the chamber 1 is discharged from a steam / gas outlet 50a provided on the upper portion of the jacket 50, The liquid processed in the inner chamber 30 is discharged from a liquid outlet 50 b provided at the lower portion of the jacket 50. In FIG. 2, reference numeral 51 denotes a cooling plate disposed on the outer upper surface of the inner chamber 30 of the processing chamber 1 and the upper surface of the outer jacket 50. The plate 51 has coolant passages 51 a and 51 b through which the coolant flows. Is formed. Reference numeral 40e denotes a high-speed rotation mechanism that applies high-speed rotation to the rotary shaft 40. The mechanism 40e includes a speed increasing mechanism such as an electric motor and a speed increasing gear train, a bearing, and the like (not shown).
In FIG. 2, a processing liquid supply port 3PN containing PCB is formed at the center of the bottom 1a of the processing chamber 1. 4N is a supply port of nitrogen formed in the same bottom portion 1a, and a passage is formed so that the supplied nitrogen is supplied into the chamber inner chamber 30 and the outer chamber jacket 50.

In the present invention, the processing chamber 1 having the above-described configuration is supplied with the liquid to be processed containing PCB and is detoxified. This will be described below.
A liquid containing PCB in which PCB liquid and kerosene are mixed in a weight ratio of about 10:90 to 80:20 is fed into the storage tank 2 in FIG.
Metal sodium melted at 100 ° C. to 150 ° C. in this liquid is added by the adding device 3 while being fed to the processing chamber 1. The metallic sodium particles to be added are mixed in the liquid containing the PCB by the mixer 3A, and the sodium is suspended and dispersed in the liquid with an average particle diameter of 1 μm to 3 μm.

  On the other hand, in the processing chamber 1, rotation is applied to the rotating shaft 40 from the high-speed rotating mechanism 40 e, and the rotating disk 10 having a small hole 10 a attached to the rotating shaft 40 is rotated about 12,000 rpm as an example. Is granted. The rotation to the rotating disk 10 is caused by the fact that the small hole 10a is provided in the disk 10 and that the rotating disk 10 is sandwiched between the fixed plates 20, thereby causing a strong negative in the chamber inner chamber 30. Create pressure. This negative pressure sucks into the chamber the processing liquid containing PCB premixed with the above-mentioned sodium metal.

  The processing liquid containing PCB that is fed so as to be sucked into the chamber due to the negative pressure generated in the processing chamber 1 is a plane in which the disk 10 with a small hole 10a that rotates at high speed and the fixed plate 20 are opposed to each other. High-speed turbulence is generated by the small holes 10 a of the rotating disk existing on the opposing surface, and thereby ultrasonic vibration is generated inside the chamber inner chamber 30.

  On the other hand, the processing liquid preheated to 100 ° C. to 150 ° C. outside the processing chamber 1 rises to about 150 ° C. to 250 ° C. or less by the action of turbulent flow and ultrasonic vibration inside the chamber inner chamber 30. At the same time as it is heated, it receives a strong centrifugal force by the disk 10 that rotates at a high speed, so that it receives a strong acceleration of 20,000 G to 40,000 G in the horizontal direction (lateral direction).

  The treatment liquid containing PCB subjected to the mechanical action as described above contains chlorine and biphenyl separated from the PCB by the intermolecular bond between chlorine and biphenyl forming the PCB, thereby containing sodium chloride and biphenyl. Processed into liquid.

The change of the liquid containing PCB to the liquid containing salt and biphenyl is sent from the outlet 30a provided in the upper portion 1b of the chamber 1 (inner chamber 30). Then, the liquid is sent to the condenser 5 from the outlet 50 b at the lower part of the jacket 50, where it is cooled and accommodated in the primary treated tank 6. At this time, the PCB concentration is measured by the measuring means 10 and is returned to the storage tank 2 from the primary treated tank 6 until the density becomes equal to or lower than a predetermined value, preferably zero, and the mechanochemical action is repeatedly performed in the processing chamber 1. receive.
Further, the vapor / gas generated in the inner chamber 30 of the processing chamber 1 is sent from the outlet 30 a to the condenser 8 from the outlet 50 a at the upper part of the outer chamber jacket 50, and the liquefied one is sent to the primary processed tank 6. It is sent.

  Thus, when the measurement means 10 detects that the PCB concentration in the primary processing tank 6 containing the PCB processed in the processing chamber 1 has become zero, the PCB processed in the processing chamber 1 is removed. Since the contained liquid has been detoxified, the treated liquid is sent to the treatment completion tank 61, and the detoxification process of the treatment liquid containing PCB contained in the storage tank 2 is completed according to the present invention. To do.

  The present invention is as described above, and the conventional PCB detoxification processing technology has been difficult to perform an efficient detoxification process at a low cost. However, in the present invention, an in-plane is provided at the center of the processing chamber. A plurality of rotating disks having a plurality of through holes are attached to a rotating shaft, and a fixed annular body is provided on the inner peripheral wall surface of the chamber so as to sandwich the rotating disks from above and below. In the chamber, when the rotating disk is rotated between 10,000 to 18,000 rpm between the stationary annular bodies, an inert gas is supplied into the processing chamber, and the PCB liquid to be processed and kerosene are in a weight ratio. In this mixture, metallic sodium heated to 100 ° C. to 150 ° C., which is equivalent to chlorine in PCB, is added to the mixed solution, and gold having an average particle diameter of 1 μm to 3 μm is added. By supplying the processing solution mixed so that genus sodium is suspended and dispersed into the chamber from the bottom side, the intermolecular bond of the processing solution is cut and the PCB chlorine separated and the metallic sodium are combined. Then, the treated liquid containing biphenyl and salt generated thereby can be discharged from the discharge part at the upper part of the chamber to detoxify the PCB, so that the PCB can be made harmless efficiently without using a sealed pressure vessel. It is extremely useful industrially.

DESCRIPTION OF SYMBOLS 1 Processing chamber 2 Storage tank 3 Sodium addition apparatus 3A Mixer 4 Chisso supply means 5 Processed liquid condenser 6 Primary processing tank 61 Processing completion tank 7 Return pump 8 Steam condenser 9 Filtration tank 1a Bottom part of the inner chamber 30 in the chamber 1 1b Upper part 10 of inner chamber 30 in chamber 1 Rotating disk 10a Small hole 20 Fixed plate (fixed annular body)
30 Chamber inner chamber 40 Rotating shaft 50 Outer chamber jacket

Claims (4)

At the center of the processing chamber, a plurality of rotating disks having a diameter of 250 mm to 350 mm having a plurality of through holes in the surface are arranged attached to the rotating shaft, and the rotating disks are fixed so as to sandwich the rotating disks from above and below. In rotating the rotating disk at a high speed between fixed annular bodies in a processing chamber having a configuration in which the body is provided on the inner peripheral wall surface of the chamber,
An inert gas is supplied into the processing chamber, and a PCB liquid to be processed and kerosene are mixed at a weight ratio of 10:90 to 80:20, and this mixed liquid is 100 ° C., which is equivalent to chlorine in PCB. While adding the metallic sodium heated to ˜150 ° C. and mixing the metallic sodium having an average particle diameter of 1 μm to 3 μm so as to be suspended and dispersed into the chamber from the bottom side, the rotating disk is By rotating at 10,000 rpm to 18,000 rpm,
The surface of the stationary annular body, the plane of the rotating disk, and the holes act to turbulently flow the gas in the chamber and the treatment liquid supplied to cause ultrasonic vibrations,
At the same time, the processing liquid in the chamber is heated to 150 ° C. or higher and 250 ° C. or lower by the action of the stationary annular body holding the gas and the processing liquid in the gap and the rotating disk, and the processing liquid is charged with 20,000 G˜ Apply 40,000G acceleration,
The chlorine of the PCB separated by cutting the intermolecular bond of the treatment liquid and the metal sodium are combined, and the treated liquid containing biphenyl and sodium chloride produced thereby is discharged from the discharge part at the top of the chamber. A method for detoxifying a PCB, which is characterized in that   The PCB detoxification method according to claim 1, wherein the liquid containing PCB is supplied to the processing chamber at a feed rate of 2 l / min to 6 l / min.   The PCB detoxification method according to claim 1 or 2, wherein the number of rotating disks is 3 to 4.   The liquid containing biphenyl and salt produced by processing in the processing chamber is discharged from the chamber, and then the PCB concentration is measured. If the PCB remains, it returns to the liquid storage section containing the PCB to be processed. A method for detoxifying a PCB according to any one of claims 1 to 3.

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