JPH0838853A - Method and apparatus for treating halogen-containing waste - Google Patents

Abstract

PURPOSE:To decompose halogen-containing waste in the presence of high temp. and high pressure water to make the waste harmless while recovering a salt as a solid. CONSTITUTION:Hydrogen chloride formed by hydrolysis and oxidative decomposition in a high pressure reaction container 16 is neutralized by an alkali aq. soln. 51A and the nutralized fluid is cooled by a cooler 6 to be sent to a gas- liquid separator 28 and a liquid phase having a salt dissolved therein is sent to a flash tank 70 to recover the salt as a solid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing method and a processing apparatus suitable for decomposing environmentally harmful halogen-containing waste in water under high temperature and high pressure.

[0002]

2. Description of the Related Art Combustion / pyrolysis method, plasma decomposition method,
Catalytic decomposition method, reagent decomposition method, and supercritical water decomposition method are known (for reference, for example, Koichi Mizuno, Pollution and Countermeasures,
Vol. 28, No. 8,752-758 (199
0)).

[0003]

Although the above-mentioned various methods are known as the decomposition technology of CFC, which is a typical halogen-containing compound, there are problems inherent in any of the above-mentioned methods and they have been completed. Not technology. Regarding the CFC decomposition method using supercritical water (see Japanese Patent Application Laid-Open No. 2-274269), it is hard to say that the flow of the decomposition treatment and the method and apparatus for the post-treatment are disclosed, regardless of the basic idea. Is the actual situation.

In view of the above problems, the present invention intends to provide a treatment method and a treatment device in consideration of the recovery of the salt produced during the decomposition treatment of the halogen-containing waste.

[0005]

The present invention comprises a preheater, a high-pressure reactor, a cooler, and a gas-liquid separator, wherein halogen-containing waste is treated with water in the presence of high-temperature high-pressure water in the high-pressure reactor. In the treatment method of decomposing by the hydrolysis reaction and / or the oxidative decomposition reaction by the oxygen-containing fluid, the following technical means are taken to achieve the above-mentioned object.

That is, in the treatment method according to claim 1, the hydrogen halide produced by the decomposition is neutralized with an aqueous alkali solution at the same time as or after the reaction, and the neutralized fluid is introduced into a cooler and cooled. After separating into a gas phase and a liquid phase with a gas-liquid separator, the liquid phase in which the salt is dissolved is introduced into a flash tank to evaporate water and recover the salt as a solid. is there.

According to a second aspect of the present invention, the liquid phase after the gas-liquid separation is separated into a liquid phase having a high salt concentration and a liquid phase having a low salt concentration, and the liquid phase having the low salt concentration. Is used by circulating it to a preheater or high-pressure reactor for reuse, while the liquid phase with a high salt concentration is introduced into a flash tank to evaporate water and recover the salt as a solid. is there.

The treatment method according to claim 3 is characterized in that the water supplied to the preheater or the high-pressure reactor is heated by exchanging heat with the steam after salt separation in the flash tank. The treatment method according to claim 4 is characterized in that water condensed by heat exchange is circulated and supplied to a preheater or a high-pressure reactor for reuse.

Further, the present invention comprises a preheater, a high-pressure reactor, a cooler, and a gas-liquid separator, and the halogen-containing waste is hydrolyzed with water in the presence of high-temperature high-pressure water in the high-pressure reactor. In a processing apparatus that decomposes by an oxidative decomposition reaction with an oxygen-containing fluid, and / or the following technical measures are taken to achieve the above object. That is, the treatment apparatus according to claim 5 includes the first supply means for supplying the halogen-containing waste to the high-pressure reaction container, and the water for the hydrolysis reaction and / or the oxygen-containing fluid for the oxidative decomposition reaction. A second supply means for supplying the high-pressure reaction vessel, a third supply means for supplying the alkaline aqueous solution to the high-pressure reaction vessel, and a cooler in a path through which the neutralized fluid neutralized by the alkaline aqueous solution flows out from the high-pressure reaction vessel. Equipped with a gas-liquid separator,
It is characterized in that it is equipped with a flash tank for separating the gas phase and the liquid phase by the gas-liquid separator and evaporating the water in the liquid phase in which the salt is dissolved to recover the salt as a solid. .

In the processing apparatus according to the sixth aspect, the liquid phase separated by gas-liquid separation is separated into a liquid phase having a high salt concentration and a liquid phase having a low salt concentration between the gas-liquid separator and the flash tank. And a reverse osmosis membrane device for The treatment apparatus according to claim 7 is characterized by comprising a heat exchanger that heats the water supplied to the preheater or the high-pressure reactor by exchanging heat with the steam separated from the salt in the flash tank. is there.

[0011]

The halogen-containing waste 21A supplied to the high-pressure reactor 61 is decomposed by the hydrolysis reaction with the water 14A and / or the oxidative decomposition reaction by the oxygen-containing fluid 56A in the presence of high-temperature high-pressure water. Hydrogen halide generated by this decomposition treatment is neutralized by an alkaline aqueous solution,
The neutralized fluid is cooled by passing through the cooler 62, and then separated into a gas phase and a liquid phase by the gas-liquid separator 28.

The liquid phase in which the salt is dissolved is 100 ° C. under atmospheric pressure.
The water is introduced into the heated flash tank 70, the water is evaporated, and the salt is recovered as a solid.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention and their operation will be described below with reference to the drawings. In each embodiment, common parts are designated by common symbols. In FIG. 1 showing the first embodiment of the present invention, the water 14A in the tank 14 is closed by a shutoff valve 15
A preheater 60 which is pressurized by a high-pressure pump 16 via a heater and is externally heated by a heater 63 via a check valve 17.
Sent to.

The halogen-containing wastes 21A such as CFCs and halons in the tank 21 which are non-processed substances are similarly fed to the preheater 60 via the stop valve 22, the high pressure pump 23 and the check valve 24. Similarly, the alkaline aqueous solution 51A is fed from the tank 51 to the preheater 60 through the shutoff valve 52, the high pressure pump 53 and the check valve 54.

The water, the halogen-containing waste and the alkaline aqueous solution which have been fed to the preheater 60 and preheated are then fed to the high pressure reactor 61. This high-pressure reactor is also heated from the outside or an internal heating means as required. Here, the halogen-containing waste undergoes a hydrolysis reaction with water and is decomposed into carbon dioxide and hydrogen halide. The hydrogen halide is neutralized with alkali to produce salt and water.

The halogen-containing waste and / or the alkaline aqueous solution may be directly fed to the high pressure reactor inlet without passing through the preheater. The neutralizing fluid flowing out of the high-pressure reactor is then sent to the cooler 62 to be cooled, and the gas-liquid separator 2 is further cooled.
8 and is separated into gas and liquid. The gas phase mainly composed of carbon dioxide is discharged through the pressure reducing valve 30. The liquid phase is an aqueous phase in which salt is dissolved, and the pressure reducing valve 31 whose liquid level is controlled
Via atmospheric pressure to the flash tank 70 heated to 110 ° C. by the heater 71. The salt is recovered as a solid from the bottom of the flash tank via path 72 and the vaporized steam in the flash tank is route 73.
It is discharged into the atmosphere through.

A concrete example of the first embodiment is shown in FIG. In this specific example, a part of a preheater, a high pressure reactor and a part of a cooler are provided in a cylindrical high pressure reaction vessel 1. This high-pressure reactor is hermetically sealed by covering the upper and lower openings of a cylindrical high-pressure reactor main body 2 with sealing members 5 and 6 with lid members (upper lid 3 and lower lid 4). Is formed. In a specific example, one end portion 7a of the flow passage forming member 7 that forms the inner and outer flow passages 11 and 12 in the high pressure chamber 1A is fixedly provided to the lower lid 4, and the other end portion 7b is a free end and faces each other. The inner channel 12 which is long in the axial direction in cooperation with the upper lid 3 which is the other lid member
The mixing flow path 8 is formed to connect the outer flow path 11 and the ring-shaped outer flow path 11.

The flow path forming member 7 is formed of a heat resistant material such as Inconel in a cylindrical shape. The flow path forming member 7
A supply means A for pressurizing and supplying water 14A to one of the inner and outer flow paths 11 and 12, that is, the outer flow path 11 in the specific example, is connected to the lid member on the side where the water is fixed, in the specific example, the lower lid 4. . In the specific example, an annular header 9 is formed on the lower lid 4, and the header 9 and the outer flow path 11 are communicated with each other through a plurality of through holes 10 formed at equal intervals in the circumferential direction. 1 conduit 18
Is connected.

Further, a tank 14 for water 14A, a shutoff valve 15, a high-pressure pump 16 and a check valve 17 are arranged in series in that order in the first pipeline 18, and a preheater 19 for heating is provided. Is provided. On the other hand, the upper lid 3 is connected with supply means B1, B2, B3 capable of pressurizing and supplying the halogen-containing waste 21A, the alkaline aqueous solution 51A, and the oxygen-containing fluid 56A such as air, oxygen and hydrogen peroxide.

In a specific example, the halogen-containing waste 21A has a tank 21, a shutoff valve 22, a high-pressure pump 23, and a check valve 24 arranged in series in this order, and a high-pressure reaction container is passed through a through hole 20 formed in the upper lid 3. Sent to. The alkaline aqueous solution 51A includes a tank 51, a shutoff valve 52, and a high pressure pump 5.
3, and the check valve 54 are arranged in series in this order, and are fed to the high-pressure reaction container through the through hole 50 formed in the upper lid 3. The oxygen-containing fluid 56A is supplied to the tank 56, the shutoff valve 57,
A high-pressure pump 58 and a check valve 59 are arranged in series in this order, and are fed to the high-pressure reaction container through a through hole 55 formed in the upper lid 3.

When the halogen-containing waste and / or the oxygen-containing fluid is in a gaseous state, the tank 21 and / or the tank 56 become cylinders, and the booster pump temporarily accumulates the pressure in the accumulator and reduces the pressure by the pressure reducing valve. It is also possible to use a means for supplying pressure. The lower lid 4 is formed with an outflow hole 13 for communicating a fluid mixture (neutralizing fluid) flowing down the inner flow path 12, and the outflow hole 13 has a gas-liquid separating means C. Are connected.

In a specific example, a pipe 28A is connected to the outflow hole 13, and a cooler 27 and a gas-liquid separator 28 are arranged in series in this pipe 28A, and the gas-liquid separator 28 has first and second branches. Tube 2
8B and 28C are connected and the gas is the first branch pipe 28B.
The liquid is released into the atmosphere from the pressure reducing valve 30 provided in the second branch pipe 28C and flows through the pressure reducing valve 31 (the opening / closing valve that controls the opening and closing in conjunction with the liquid level) provided in the second branch pipe 28C under atmospheric pressure by the heater 71 at 110 ° C. Sent to the flash tank 70 heated to
The water is vaporized and released to the atmosphere as steam from path 73, while the salt is recovered as a solid from the bottom of the flash tank via path 72.

The second embodiment is shown in FIG. In FIG. 3, the high-pressure reaction container device 1 is covered by a lid member (upper lid 3 and lower lid 4) at the upper and lower openings of a container body 2 formed in a cylindrical shape, preferably a cylindrical shape, with sealing members 5 and 6. By doing so, the airtight high-pressure chamber 1A is formed. In the embodiment, the flow path forming member 7 that forms the inner and outer flow paths 11 and 12 in the high pressure chamber 1A is provided with one end portion 7a thereof fixed to the lower lid 4, and the other end portion 7b is a free end and faces each other. In cooperation with the other lid member, that is, the upper lid 3, a mixing channel 8 is formed which connects the axially long inner channel 12 and the annular outer channel 11.

The flow path forming member 7 is formed of a heat-resistant material such as Inconel into a cylindrical shape. However, the free end side near the mixing flow path 8 is a reaction field at a high temperature accompanied by the generation of strong acid, and thus the reaction is performed. As the portion 12A, it is desirable to apply a corrosion resistant layer (including a film) 7A to the inner surface of the portion 12A by spraying or lining ceramics such as alumina, silicon nitride, or silicon carbide.

In this case, it is recommended that the corrosion resistant layer 7A be detachably used as a liner because it is expected that the portion will be severely damaged. A cover member on the side where the flow path forming member 7 is fixed, in the embodiment, a lower lid 4 is provided with a supply means for pressurizing and supplying water 14A to one of the inner and outer flow paths 11 and 12, and in the embodiment, the outer flow path 11. A is connected.

In the embodiment, an annular header 9 is formed on the lower lid 4, and the header 9 and the outer flow path 11 are communicated with each other through a plurality of through holes 10 formed at equal intervals in the circumferential direction. A first conduit 18 is connected to the. Furthermore, the first conduit 18
A tank 14 for water 14A, a shutoff valve 15, a high pressure pump 16, a throttle valve 16a and a check valve 17 are arranged in series in that order, and a preheater 1 for heating is provided.
9 is provided.

On the other hand, the upper lid 3 has a halogen-containing waste 21.
A, a supply means B capable of supplying an alkaline aqueous solution 51A under pressure
1, B2 are connected. In the embodiment, the halogen-containing waste 21A includes the tank 21, the shutoff valve 22, and the high pressure pump 2.
3, and the check valve 24 are arranged in series in this order, and are fed to the high-pressure reaction container through the through hole 20 formed in the upper lid 3. The alkaline aqueous solution 51A has a tank 51 and a shutoff valve 5.
2, the high-pressure pump 53, and the check valve 54 are arranged in series in this order, and are fed to the high-pressure reaction container through the through hole 50 formed in the upper lid 3.

When the halogen-containing waste is in a gaseous state, the tank 21 becomes a cylinder or the like, from which the booster pump temporarily stores the pressure in the accumulator, and the pressure reducing valve decompresses the pressure before supplying it. . The lower lid 4 is formed with an outflow hole 13 for the fluid mixture that is in communication with the inner flow path 12 and flows down through the inner flow path 12.
The gas-liquid separation means C is connected to the.

In a specific example, a pipe 28A is connected to the outflow hole 13, and a restrictor 26, a cooler 27, and a gas-liquid separator 28 are arranged in series in the pipe 28A, and the gas-liquid separator 28 has a first line. The first and second branch pipes 28B and 28C are connected, and the gas is released to the atmosphere from the pressure reducing valve 30 provided in the first branch pipe 28B.
The liquid is a pressure reducing valve 31 (liquid level meter 3) provided in the second branch pipe 28C.
2 is sent to the electrodialysis device 81 via an on-off valve that controls opening and closing in conjunction with 2. In the electrodialysis device, the aqueous salt solution is separated into an aqueous solution having a high salt concentration and an aqueous solution having a low salt concentration.

The aqueous solution having an increased salt concentration is sent from the outlet of the electrodialyzer 81 through the conduit 84 to the flash tank 70 heated to 110 ° C. by the heater 71 under atmospheric pressure by the pressure reducing valve 82. The salt is recovered as a solid from the bottom of the flash tank via path 72. On the other hand, the aqueous solution whose salt concentration has been lowered is sent from the other outlet of the electrodialysis device 81 to the high-pressure pump 86 via the line 85 and the stop valve 83, and the aqueous solution pressurized here is supplied with the check valve 87.
After that, it is fed again to the outer flow path 11 of the high-pressure reactor 1 and reused.

The diaphragm 16a is composed of high pressure pumps 16 and 8
It is to make the flow rate relaxation with 6 constant, and
The same process can be performed by replacing the electrodialysis device with a reverse osmosis membrane device. In the above high-pressure reactor apparatus, as a measure against the tendency that the gas component (mainly composed of carbon dioxide) generated in the reaction part 12A tends to move to the upper part of the reaction part in terms of buoyancy, From the upper part of the inside of the free end of the flow path forming member 7, the through hole 35 formed in the conduit 34 and the upper lid 3 (the conduit 34 is fixed to the through hole 35,
It penetrates through A and is opened at the lower end of the reaction part 12A), and is connected to the second gas-liquid separation means D.

In the embodiment, a fourth pipe line 37A is connected to the through hole 35, and a cooler 36 and a gas-liquid separator 37 are arranged in series in the fourth pipe line 37A. Is the first
The two branch pipes 37B and 37C are connected, the gas is decompressed by the pressure reducing valve 38 provided in the first branch pipe 37B and released to the atmosphere from the closing valve 39, while the fluid accompanying the gas component is the second branch. Pressure reducing valve 40 (liquid level gauge 41) provided in the pipe 37C
It is configured to be discharged to the storage tank 42 via an opening / closing valve that controls opening / closing in conjunction with.

The third embodiment is shown in FIG. The steam evaporated in the flash tank 70 is sent to the heat exchanger 91. The water 14A in the water tank 14 is fed to the heat exchanger 91 through the shutoff valve 15, the water supply pump 16 ', and the check valve 17, and exchanges heat with the steam flowing from the flash tank 70 through the conduit 73. To do. Here, the water is heated, further pressurized by the high pressure pump 86, and sent to the outer flow path 11 of the high pressure reaction container 1 through the check valve 87.

A fourth embodiment is shown in FIG. The steam evaporated in the flash tank 70 is sent to the heat exchanger 91. The water 14A in the water tank 14 is fed to the heat exchanger 91 through the shutoff valve 15, the water supply pump 16 ', and the check valve 17, and exchanges heat with the steam flowing from the flash tank 70 through the conduit 73. To do. Here, the water is heated and pressurized by the high-pressure pump 86 through the check valve 95, and the check valve 87.
And is fed to the outer flow path 11 of the high-pressure reactor 1. On the other hand, the steam that has flowed in from the pipe 73 is condensed in the heat exchanger 91 and becomes hot water and flows out. A part or all of this hot water is discharged through the stop valve 92, or a part or all of this warm water is passed through the stop valve 93 and the water supply pump 94 and the check valve 9 are discharged.
It is pressurized by the high-pressure pump 86 via 6 and is fed to the outer flow path 11 of the high-pressure reactor 1 via the check valve 87 to be reused.

[0035]

As described above, the present invention has been an unsolved problem in the decomposition and detoxification treatment of halogen-containing wastes represented by fluorocarbons in the presence of high temperature and high pressure water. The present invention provides a treatment method and a treatment device in consideration of a method of recovering salts which are decomposition products and an energy recovery method associated therewith, and the present invention remarkably contributes to the reduction of destructive substances in the global environment.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a first embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a specific example of the first embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a second embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a third embodiment of the present invention.

FIG. 5 is a conceptual diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 High-pressure reaction vessel device 14A water 14 Water tank 21A Halogen waste 21 Halogen waste tank 28 Gas-liquid separator 51A Alkaline aqueous solution 51 Alkaline aqueous solution tank 61 Reactor 62 Cooler 70 Flash tank

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B01D 53/77 // B01D 61/08 9538-4D 61/28 9538-4D B01D 53/34 134 F

Claims (7)

[Claims] 1. A preheater, a high-pressure reactor, a cooler, and a gas-liquid separator, wherein the halogen-containing waste is hydrolyzed with water and / or oxygen in the presence of high-temperature high-pressure water in the high-pressure reactor. In a treatment method of decomposing by an oxidative decomposition reaction with a contained fluid, hydrogen halide produced by the decomposition is neutralized with an alkaline aqueous solution simultaneously with or after the reaction,
The neutralized fluid is introduced into a cooler and cooled, and then separated into a gas phase and a liquid phase by a gas-liquid separator, and then the liquid phase in which salt is dissolved is introduced into a flash tank to evaporate water. A method for treating halogen-containing waste, which comprises recovering salt as a solid. 2. The liquid phase after gas-liquid separation is separated into a liquid phase having a high salt concentration and a liquid phase having a low salt concentration, and the liquid phase having a low salt concentration is a preheater or a high-pressure reactor. The treatment method according to claim 1, wherein the liquid phase having a high salt concentration is introduced into a flash tank to evaporate water to recover the salt as a solid, which is circulated and recycled for reuse. 3. The treatment method according to claim 1, wherein the water supplied to the preheater or the high-pressure reactor is heated by exchanging heat with steam after salt separation in the flash tank. 4. The treatment method according to claim 3, wherein the water condensed by the heat exchange is circulated and supplied to the preheater or the high-pressure reactor for reuse. 5. A preheater, a high-pressure reactor, a cooler, and a gas-liquid separator, wherein the halogen-containing waste is hydrolyzed with water and / or oxygen in the presence of high-temperature high-pressure water in the high-pressure reactor. In a treatment apparatus for decomposing by an oxidative decomposition reaction with a contained fluid, a first supply means for supplying a halogen-containing waste to a high-pressure reaction vessel, water for a hydrolysis reaction and / or oxygen-containing for an oxidative decomposition reaction Second supply means for supplying a fluid to the high-pressure reaction vessel, third supply means for supplying an alkaline aqueous solution to the high-pressure reaction vessel, and cooling the neutralized fluid neutralized by the alkaline aqueous solution into a path flowing out from the high-pressure reaction vessel. And a gas-liquid separator, and a flash tank for separating the gas phase and the liquid phase by the gas-liquid separator and evaporating the water in the liquid phase in which the salt is dissolved to recover the salt as a solid. Processor of halogen-containing waste, characterized in that is. 6. A dialysis device or reverse osmosis for separating a liquid phase obtained by gas-liquid separation into a liquid phase having a high salt concentration and a liquid phase having a low salt concentration between a gas-liquid separator and a flash tank. The processing apparatus according to claim 5, further comprising a membrane device. 7. The heat exchanger according to claim 5, further comprising a heat exchanger for heating the water supplied to the preheater or the high-pressure reaction vessel by exchanging heat with the steam separated from the salt in the flash tank. Processing equipment.