JPH10277571A - Method and device for treating organic alkali waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decompose organic alkali waste water having any concentration in a short period of time by holding waste water containing organic alkali in a supercritical state. SOLUTION: This device is provided with a high pressure pump 3 for sending waste liquid 10 to the device from a waste liquid piping, a heater 1 for heating the device and a pressure regulating valve 2 for tightly closing the device when the device is heated. And for treating nitrogen based organic alkali waste water such as tetramethylammonium hydroxide, the waste water is held in a treating vessel 100 in a supercritical state to decompose organic alkali. The supercritical state is preferably such that temperature is 375 deg.C or higher, pressure 22 MPa or higher, and waste water density 328 kg/m<3> or more. And the treating period, which depends on the treating capacity, is normally 10 min. or less. For treating organic alkali waste water, when atmospheric gas or aeration gas is brought into contact with the organic alkali waste water, the atmospheric or aeration gas is gas which is selected from air, nitrogen, and helium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for treating a nitrogen-based organic alkali waste liquid.

[0002]

2. Description of the Related Art In recent years, as electronic devices such as personal computers and mobile phones have become more sophisticated and smaller, semiconductor devices such as ICs and LSIs have been increasingly integrated. Along with this, the use amount of nitrogen-based organic alkalis such as tetramethylammonium hydroxide (TMAH) and β-hydroxyethyltrimethylammonium hydroxide (choline) used as a developer in the positive photoresist process has increased. I have. Further, these nitrogen-based organic alkalis are also used for cleaning Si wafers and liquid crystal glass substrates, and the amount of discharge together with the development waste liquid is rapidly increasing year by year. Therefore, recently, various recycling methods and decomposition methods have been attempted due to environmental conservation efforts to reduce the amount of waste generated. In the recycling method, since the nitrogen-based organic alkali developer contains a slight amount of a surfactant to increase the wettability, the waste liquid generates bubbles and the regeneration operation is difficult. In addition, the quality as a reagent after regeneration cannot be guaranteed, and it has not been possible to use it as a developer or cleaning agent for semiconductors. Recently, pH
Although a method of reusing it as an adjusting agent is also mentioned, since the concentration originally used is 3% or less, a concentration operation is required, and it was not cost-effective to use as a pH adjusting agent. As for the decomposition method, nitrogen-based organic alkali is hardly decomposed and is relatively stable in a natural environment, so that forced microbial decomposition by the activated sludge method is often performed. However, in this activated sludge method, it is difficult to treat high-concentration effluent to reduce the microbial activity, and it is necessary to dilute the effluent with water in advance, and a large amount of sludge is generated. The maintenance of microorganisms is required, the processing efficiency decreases if a large amount of surfactant is mixed in before processing,
And so on. Also, the treatment is only a two-stage treatment method in which nitrogen-based organic alkali is decomposed into nitrate ions via ammonia under aerobic conditions, and this is nitrified by adding methanol or the like under anaerobic conditions to decompose into nitrogen gas. And the required area of the processing system was large.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method and an apparatus for decomposing an organic alkali waste liquid having an arbitrary concentration in a short time.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a method for treating organic alkali wastewater according to claim 1 is to maintain wastewater containing organic alkali in a supercritical state. Wherein the organic alkali is decomposed.

According to a second aspect of the present invention, in the method of the first aspect, the supercritical state is maintained at a temperature of 374.
It is characterized in that the temperature is not less than ℃, the pressure is not less than 22 MPa, the density of wastewater is not less than 328 kg / m-3, and the treatment time is not more than 6 hours. Here, the heating temperature must be higher than the critical temperature regardless of the density and pressure of the waste liquid to be treated. This is because heat energy enhances the diffusibility of the waste liquid. Also, the pressure must exceed the supercritical pressure regardless of the density and temperature of the waste liquid to be treated. This is because the density of the waste liquid is increased and the reactivity is increased. Further, the waste liquid density must exceed the supercritical density regardless of the temperature and pressure at which the treatment is performed. This is because it balances kinetic energy and intermolecular interaction.

Although the processing time depends on the processing capacity, it is usually preferable to complete the processing in 10 minutes or less. However, it is preferable that the treatment can be performed up to about 6 hours in case of treating a large volume of wastewater. This is because a large reaction rate is obtained by the effect of solvation. The method for treating organic alkali wastewater according to claim 3 is the method according to claim 1, wherein when the wastewater containing the organic alkali is brought into contact with an atmosphere gas or an aeration gas, the atmosphere gas or the aeration gas is air, nitrogen, helium, oxygen, And a gas selected from water vapor. The gas used is preferably an oxidizing gas, but a gas such as nitrogen, helium, or argon having a low oxidizing property can be used by using an oxidizing agent or a catalyst. According to the present invention, it is possible to decompose a nitrogen-based organic alkali which was difficult to completely decompose, and it is possible to control a decomposition product by controlling an atmospheric gas. Further, the oxidation reaction can be efficiently caused by selectively using the oxidizing gas. In the method for treating organic alkali wastewater according to claim 4, the wastewater containing organic alkali according to claim 1 is a substance selected from carboxylic acid, oxidizing substance, hydrogen peroxide and / or ozone, and an aromatic compound. Is characterized by coexistence. Here, the carboxylic acid includes monocarboxylic acid, dicarboxylic acid, tricarboxylic acid, chain carboxylic acid, aromatic carboxylic acid, saturated carboxylic acid, unsaturated carboxylic acid and the like. The side chain of this carboxylic acid is preferably composed of only carbon and hydrogen, and tricarboxylic acid is particularly preferable. Also, as the oxidizing substance,
Ozone, hydrogen peroxide, chloric acid, perchloric acid, chlorous acid, hypochlorous acid, bromic acid, perbronic acid, hypobromite, hypobromite,
Orthoperiodic acid, periodic acid, iodic acid, hypoiodic acid, manganic acid, permanganic acid, technetic acid, pertechnetic acid, rhenic acid, perrhenic acid, sulfuric acid, effluent acid, peroxomonosulfuric acid, peroxodisulfuric acid , Thiosulfate,
Dithionic acid, sulfurous acid, bisulfite, thiosulfite, dithionous acid, polythionic acid, selenic acid, selenous acid, orthotelluric acid, chromic acid, dichromic acid, nitric acid, peroxonitrate, nitrous acid, peroxonitrite, nitroxylic acid , Hyponitrite, orthophosphoric acid (phosphoric acid), diphosphoric acid (pyrophosphoric acid), metaphosphoric acid, peroxomonophosphate, peroxodiphosphate, hypophosphoric acid, diphosphoric acid, phosphonic acid, phosphinic acid, arsenic acid, Examples include oxoacids such as arsenous acid, hexahydroxyantimonic acid, carbonic acid, cyanic acid, isocyanic acid, thunderic acid, orthosilicic acid, metasilicic acid, boric acid, and metaboric acid. Of these, ozone, hydrogen peroxide, and nitric acid, which decompose to harmless substances after oxidation, are particularly preferred. Further, the aromatic compound may be a polymerized one, and a compound containing a large amount of oxygen in the compound is preferable.

According to a fifth aspect of the present invention, in the method of the fourth aspect, the amount of the oxidizing substance is controlled to 0.7 to 5 times the amount of oxygen calculated from the TOC of the nitrogen-based organic alkali wastewater. It is characterized by doing.

The nitrogen-based organic alkali wastewater treatment apparatus according to claim 6, wherein the nitrogen-based organic alkali wastewater contains at least one of tetramethylammonium hydroxide and β-hydroxyethyltrimethylammonium hydroxide. . This makes it possible to decompose tetramethylammonium hydroxide and β-hydroxyethyltrimethylammonium hydroxide, which have been difficult to completely decompose under normal temperature and normal pressure. At this time, the heating temperature is preferably 100 ° C. or more at which tetramethylammonium hydroxide or β-hydroxyethyltrimethylammonium hydroxide causes a dehydration reaction irrespective of the pressure or the density of the waste liquid, since demethylation is easy to proceed. Further, it is desirable to perform the treatment for 12 hours or less from the viewpoint of achieving complete disassembly and reducing the running cost. Processing time depends on processing capacity, but usually 1
Completion in 0 minutes or less is preferable from the viewpoint of reducing running costs. However, it is preferable from the viewpoint of achieving complete decomposition that the treatment can be performed up to about 6 hours in case of treating a large volume of wastewater. 8. The apparatus for treating a nitrogen-based organic alkali wastewater according to claim 7, wherein: a treatment vessel containing wastewater containing an organic alkali; wastewater introduction means for flowing and holding the wastewater containing the organic alkali into the treatment vessel; In a nitrogen-based organic alkali wastewater treatment apparatus having supercritical forming means for maintaining wastewater containing organic alkali in a container in a supercritical state, and wastewater deriving means for removing the wastewater from the treatment container, the wastewater introduction means Further, the wastewater deriving means includes a valve, and the wastewater is continuously treated by closing the valve every predetermined time. Here, it is equipped with a pipe and a valve through which the nitrogen-based organic alkali waste liquid used in the development processing and the cleaning processing is directly flowed into the apparatus, and the valve is closed at regular intervals so that the waste liquid flowing into the apparatus can be heated. It is a device designed in.

[0009] This makes it possible to decompose the nitrogen-based organic alkali more quickly than when the treatment is performed in a batch system. Here, the reaction apparatus is a continuous operation type, a high-pressure pump for feeding the nitrogen-based organic alkali waste liquid, a heater or a heat exchanger for heating the nitrogen-based organic alkali waste liquid, and the liquid after the treatment of the nitrogen-based organic alkali waste liquid. It is desirable to have a pressure regulating valve for discharging and a gas discharging pressure regulating valve connected to the gas phase part of the reactor. The high-pressure pump and the pressure adjusting pump preferably have a pressure resistance up to 50 MPa, and the container body preferably has a pressure resistance up to 500 MPa.

According to an eighth aspect of the present invention, in the apparatus for treating a nitrogen-based organic alkaline wastewater according to the seventh aspect, the outlet means has a first valve and a second valve, and takes out the wastewater from the first valve. And then the second valve is controlled to open.

According to a ninth aspect of the present invention, in the treatment apparatus for a nitrogen-based organic alkali wastewater according to the seventh aspect, the introduction means has a first pump for introducing the wastewater containing the organic alkali, and the liquid other than the wastewater is supplied to the apparatus. High pressure is maintained by using a slurry pump in which the second pump for introducing the processing container and the first pump are connected in two stages. Claim 1
The apparatus for treating a nitrogen-based organic alkali wastewater according to claim 7, wherein the first valve, the second valve, the first pump, and the second pump are four of four in order to achieve high pressure. It is characterized in that only one is opened.

[0012] An eleventh aspect of the present invention is directed to the apparatus for treating a nitrogen-based organic alkali wastewater, wherein the treatment vessel is filled with a catalyst. The catalyst to be used is preferably one that does not dissolve in alkali or one that has been subjected to alkali resistance treatment. As a catalyst metal, palladium-based, iron-based, manganese-based, cobalt-based, nickel-based, ruthenium-based, rhodium-based, iridium-based, platinum-based, copper-based, gold-based, tungsten-based transition metal oxide or ruthenium dichloride, It is preferable to use one or a combination of two or more chlorides such as platinum dichloride or sulfides such as ruthenium sulfide and rhodium sulfide. Carriers such as metal porous are supported by carriers such as carbon, magnesia, titania, zirconia, alumina, silica, silica-alumina, activated carbon, nickel, nickel-chromium, nickel-chromium-aluminum, nickel-chromium-iron, etc. Those that have been made are preferred. The shape is preferably a pellet, granule, honeycomb, or powder.

A twelfth aspect of the present invention is the nitrogen-based organic alkali wastewater treatment apparatus according to the seventh aspect, wherein the pH of the wastewater containing the organic alkali is maintained at 10 to 4. Since this pH affects the product after treatment, it is preferable to adjust the pH to a different value depending on what is to be recovered. According to the present invention, not only can the pH be measured before the treatment and the amount of the nitrogen-based organic alkali contained can be estimated, but also the product after the treatment can be controlled by changing the pH, and the recovery of valuable resources can be achieved. It is possible to do.

According to a thirteenth aspect of the present invention, there is provided the apparatus for treating a nitrogen-based organic alkali wastewater according to the seventh aspect, wherein the treatment vessel is configured to collect a gas generated inside and send the gas to an adsorbent; A pressurized container that collects a single component gas coming out, a pipe that collects gas generated by the process, a pipe that sends compressed gas directly to the adsorbent, and separation from this adsorbent An object of the present invention is to provide an apparatus for treating a nitrogen-based organic alkali wastewater, comprising a pressurized container for collecting a single component gas generated. Depending on the treatment, carbonic acid, nitrogen, methane, ethane, oxygen,
Generates gases such as ammonia, monomethylamine, dimethylamine, trimethylamine, and alcohol. The processing solution is preferably provided with a pressure-resistant collection pipe so that these can be recovered after the processing.

According to the present invention, a compressed gas can be separated by utilizing a difference in adsorption speed, and can be recovered as a single gas in a high pressure state. According to a fourteenth aspect of the present invention, in the treatment apparatus for a nitrogen-based organic alkali wastewater according to the seventh aspect, the supercritical forming means has a heating means formed around the processing vessel. In the present invention, the following are preferable configurations.

In order to perform gas-liquid separation at the upper part of the apparatus, the vertical / horizontal ratio is made twice or more larger than that of the supercritical part to increase the separation efficiency. Further, it has a pipe for collecting gas generated by the treatment, a pipe for directly sending the compressed gas to the adsorbent, and a pressurized container for collecting a single component gas separated from the adsorbent.

In the processing apparatus, the gas-liquid separation section at the top of the processing vessel has a double structure of an internal vessel and an external vessel, and the internal vessel receives the processing liquid fed from the lower part of the apparatus in the same manner as in FIG. However, the external container circulates the waste liquid before being sent to the internal container, serves to preheat the waste liquid and cool the processing liquid, thereby increasing energy efficiency and quickly generating a supercritical fluid.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an apparatus for carrying out the processing method of the present invention is shown in FIGS. FIG. 1 shows a basic structure (first processing apparatus) of a waste liquid processing apparatus. It comprises a high-pressure pump (3) for sending waste liquid (10) from a waste liquid pipe to the device, a heater (1) for heating the device, and a pressure regulating valve (2) for sealing the inside of the device during heating. The state inside the processing container (100) is in the liquid phase (8). FIG. 2 shows a second processing apparatus in which the pressure in the processing container (100) is kept high. FIG. 2 is a heater (1) that also serves as a high-pressure pump that sends waste liquid (10) from a waste liquid pipe to the apparatus, and a pressure regulating valve (3) that seals the inside of the apparatus during heating. In addition to the above, a high-pressure pump (4) for feeding a liquid or gaseous oxidant (11), and a pressure regulating valve (7) directly attached to a liquid phase (8) and a gas phase (9) separated in the processing vessel, ( 2). In addition, a high-pressure pump (3) and a processing vessel (1) are provided so that heat of the liquid phase can be recovered.
00), a heat exchanger (5), and a heat exchanger (6) between the processing vessel (100) and the pressure regulating valve (2). In the above embodiment, it is possible to maintain a high pressure by using a slurry pump in which the pumps 3 and 4 are connected in two stages. FIG. 3 shows a third processing apparatus in which a catalyst or the like is loaded in a processing container to improve the decomposition efficiency. FIG. 3 shows the waste liquid (1) before sending the waste liquid to the processing vessel (100).
0) through the two-way valve (17) and the flow path switching valve (18).
24), from which it temporarily stays in the buffer tank (16), and is sent from the high-pressure pump (3) to the processing vessel (10).
0). A central portion in the processing vessel (100) is filled with a granular catalyst (22), and a gas (15) such as air can be bubbled through a lower portion through a high-pressure pump (14). Further, the upper part of the processing vessel (100) is separated into a liquid phase (8) and a gas phase (9) as in FIG. 2, and flows out of the apparatus from the pressure regulating valves (7) and (2) directly belonging to each. It has a structure that can be used. In the ion exchange tower, a regenerating solution flows through a regenerating solution tank (21) and a flow path switching valve (19), and a waste solution is sent to a regenerating solution processor (23). FIG. 4 shows a fourth processing apparatus improved so as to control the product after processing by changing the pH and to recover valuable resources. FIG. 4 shows a high-pressure pump (3) for sending a waste liquid (10) from a waste liquid pipe to the apparatus, a heater (1) for heating the apparatus, and a pressure regulating valve () for sealing the inside of the apparatus during heating. In addition to 3), the waste liquid temporarily stays in the control tank (25) before reaching the high-pressure pump (3), and the electrode type pH meter (26) and the combustion ultraviolet absorption TOC meter (27) can be measured and controlled. Depending on the conditions, chemical injection (including gas) (28) can be performed. Further, the nitrogen gas separated and sent to the adsorbent A (29) or the adsorbent B (30) via the pressure regulating valve (2) and the flow path switching valve (31) while the gas generated after the treatment is kept in a high pressure state. It is routed to a high pressure cylinder (34). The water and carbon dioxide adsorbed on the adsorbent can be suctioned and desorbed by a vacuum pump (35). It is premised that a supercritical state of the method for treating nitrogen-based organic alkali wastewater is realized. Typical and practical conditions for obtaining this state include a temperature of 374 ° C. or higher, a pressure of 22 MPa or higher, and a wastewater density of 328.
It is desirable that the treatment time be not less than kg / m-3 and not more than 6 hours. This will be described with reference to FIGS. FIG.
Using a treating solution having a MAH concentration of 1% and a waste solution density of 330 kg / m3, the decomposition rate (black square) and the amount of N2 produced (-◆-) were measured according to the waste solution temperature. Same as 1. From this figure, the temperature 374
Decomposition has started above ℃. FIG. 6 shows the results obtained by using the same processing solution as in FIG. 5 and measuring the decomposition rate (black squares) and the amount of N2 produced (− ◆ −) according to the waste liquid pressure. The same as in the case of 5. From this figure 2
It can be seen that decomposition is promoted at 2 MPa or more. FIG. 7 shows the results obtained by measuring the amount of N2 produced as the density of the waste liquid increases, using the same processing solution as in FIG. 5, and the other conditions are the same as in FIG. In the figure,-◆-is 3
N2 production data at 78 ° C, black squares indicate N at 376 ° C
2 and the black triangles indicate the N2 generation data at 374 ° C., respectively. From this figure, wastewater density 328kg
It can be seen that decomposition is promoted at / m-3 or more. Of course, depending on the conditions, it can be decomposed even at the above-mentioned temperature, pressure and waste liquid density, but the above-mentioned conditions are practical values.

[0019]

【Example】

(Embodiment 1) As the processing apparatus, the first processing apparatus shown in FIG. 1 was used. AD-1 manufactured by Tama Chemical Industry as waste liquid for processing
A resist solution (PFP IX, manufactured by Nippon Synthetic Rubber Co., Ltd.) was used for 500 mL of 0 (0.21 M tetramethylammonium hydroxide). The waste liquid was sent by the high-pressure pump 3, and the heater 1 and the pressure regulating valve 3 were controlled so that the temperature was 380 ° C. and the pressure was 23.6 MPa. After the treatment, a waste liquid sample was collected from the pressure regulating valve 2, and the waste liquid sample before the treatment was combined and analyzed. Table 1 shows the results. From the results, it was found that tetramethylammonium hydroxide, which is a nitrogen-based organic alkali in the waste liquid, was decomposed by 99.9% or more. Table 1 shows the analysis values before and after the treatment.

[0020]

[Table 1]

As described above, in biological treatment, 24% is required for decomposition to nitrogen.
Although it took more time, processing could be performed in a short time. (Embodiment 2) In the disassembly, the second processing apparatus shown in FIG. 2 was used.

As a waste liquid sample to be treated, AD-10 (0.21M tetramethylammonium hydroxide) manufactured by Tama Chemical Industry Co., Ltd.
500mL of resist (PFP I made by Nippon Synthetic Rubber)
X)-A waste liquid obtained by subjecting ten silicon wafers after the exposure treatment to a development treatment was used. 10 mL of a 1% aqueous hydrogen peroxide solution as an oxidizing agent was sent to 100 mL of a waste liquid sample, and the temperature was 38%.
The heater 1 and the pressure regulating valve 3 were controlled so as to be 0 ° C. and a pressure of 23.6 MPa, and a continuous treatment was performed for a residence time of 30 minutes.
A waste liquid sample was collected from the pressure regulating valve 7 after the treatment, and the waste liquid sample before the treatment was combined and analyzed. Table 2 shows the results. From the results, it was found that tetramethylammonium hydroxide, which is a nitrogen-based organic alkali in the waste liquid, was decomposed by 99.9% or more. Table 1 shows the analysis values before and after the treatment.

[0023]

[Table 2]

(Embodiment 3) For the disassembly, the third processing apparatus shown in FIG. 3 was used. A resist (PFP IX made by Nippon Synthetic Rubber Co., Ltd.) was applied to 500 mL of AD-10 (0.21 M tetramethylammonium hydroxide) manufactured by Tama Chemical Industry as a waste liquid sample to be treated.
A waste liquid obtained by developing 0 sheets was used. Pd as catalyst
/ ZrO2 (a zirconia-supported palladium catalyst) having a diameter of 10 mm was used. The waste liquid sample was sent to an ion exchange tower A filled with a cation exchange resin (MCI manufactured by Mitsubishi Kasei) and was adsorbed as tetramethylammonium ions. The liquid discharged from the ion exchange tower is directly drained,
After 30 minutes, the piping was switched so that the waste liquid was sent to the ion exchange tower B. At the same time as the piping was switched, 500 mL of a 1M nitric acid solution was sent to the ion exchange tower A as a regenerating solution, which was sent to the buffer tank. When the regenerating solution is sent in the buffer tank, the sensor is activated,
The waste liquid sample was sent to the processing container by a high-pressure pump. Also,
Air was sent in from the lower part of the processing vessel and bubbled in the liquid phase. In this state, the temperature is 380 ° C. and the pressure is 23.6.
The heater and the pressure regulating valve were controlled so that the pressure became MPa, and a continuous treatment was performed with a residence time of 10 minutes. A waste liquid sample was collected from the pressure regulating valve after the treatment, and the waste liquid sample before the treatment was combined and analyzed. Table 3 shows the results. From the results, it was found that tetramethylammonium hydroxide, which is a nitrogen-based organic alkali in the waste liquid, was decomposed by 99.9% or more. Table 3 shows the analysis values before and after the treatment.

[0025]

[Table 3]

(Example 4) For disassembly, the first processing apparatus shown in FIG. 1 was used. 500mL resist (PFP IX made by Nippon Synthetic Rubber) for AD-10 (0.21M tetramethylammonium hydroxide) manufactured by Tama Chemical Industry as a waste liquid sample to be treated-Silicon wafer 1 after exposure treatment
A waste liquid obtained by developing 0 sheets was used. The waste liquid was sent by a high-pressure pump, and a heater and a pressure regulating valve were controlled so that the temperature was 380 ° C. and the pressure was 23 MPa, and a continuous treatment was performed with a residence time of 2 hours. A waste liquid sample was collected from the pressure regulating valve after the treatment, and the waste liquid sample before the treatment was combined and analyzed. Table 4 shows the results. From the results, it was found that tetramethylammonium hydroxide, which is a nitrogen-based organic alkali in the waste liquid, was decomposed by 99.9% or more. Table 4 shows the analysis values before and after the treatment.

[0027]

[Table 4]

(Embodiment 5) For the disassembly, the fourth processing apparatus shown in FIG. 4 was used. A resist (PFP IX made by Nippon Synthetic Rubber Co., Ltd.) was applied to 500 mL of AD-10 (0.21 M tetramethylammonium hydroxide) manufactured by Tama Chemical Industry as a waste liquid sample to be treated.
A waste liquid obtained by developing 0 sheets was used. This waste liquid is retained in the control tank until the volume becomes 2 L, and the pH is adjusted to pH.
And TOC were monitored. As a result, pH 14.0, TO
Since it was C3000 ppm, water was flowed from the liquid injector to dilute the solution to pH 10.0 and TOC 1.2 ppm. After dilution, the solution is sent to the processing vessel via a high-pressure pump,
The heater and the pressure regulating valve were controlled so that the temperature was 23 ° C. and the pressure was 23 MPa, and continuous treatment was performed with a residence time of 2 hours. After the treatment, the gas generated from the pressure regulating valve on the gas phase side is sent to the adsorbent A,
Moisture and carbonic acid were adsorbed, and only nitrogen was collected in a high-pressure cylinder via a valve. Table 5 shows the result of analyzing the purity of this nitrogen. Further, a waste liquid sample was collected from the liquid phase side pressure control valve, and the waste liquid sample before the treatment was combined and analyzed. Table 5 shows the results. From this result, 99.9% of tetramethylammonium hydroxide, which is a nitrogen-based organic alkali in the waste liquid, was obtained.
% Or more. Table 5 shows the analysis values before and after the treatment.

[0029]

[Table 5]

[0030]

According to the present invention, it is possible to provide a method and an apparatus for efficiently and safely decomposing a nitrogen-based organic alkali waste solution having an arbitrary concentration in a short time by subjecting the nitrogen-based organic alkali waste solution to high-temperature and high-pressure treatment.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an apparatus showing Embodiments 1 and 4 according to the present invention.

FIG. 2 is a schematic view of an apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram of an apparatus showing a third embodiment according to the present invention.

FIG. 4 is a schematic diagram of an apparatus showing a fifth embodiment according to the present invention.

FIG. 5 is a diagram illustrating a first embodiment of the present invention.

FIG. 6 is a diagram illustrating a first embodiment of the present invention.

FIG. 7 illustrates a first embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Processing container heater 2 Liquid phase pressure regulating valve 3 High pressure pump 4 High pressure pump (for liquid / gas) 5 Heat exchanger before treatment 6 Heat exchanger after treatment 7 Gas phase pressure regulating valve 8 Liquid phase 9 Gas phase 10 Waste liquid 11 Oxidation Agent 12 Processing liquid 13 Processing gas 14 High-pressure pump (for gas) 15 Gas 16 Buffer tank 17 Valve 18 Flow path switching valve (ion exchange tower) 19 Flow path switching valve (regeneration liquid) 20 Ion exchange tower A 21 Regeneration liquid tank 22 Catalyst 23 Treatment regenerating liquid 24 Ion exchange tower B 25 Control tank 26 pH meter 27 TOC meter 28 Chemical solution injection section (including gas) 29 Adsorbent A 30 Adsorbent B 31 Flow path switching valve 32 High pressure regulating valve 33 High pressure regulating valve 34 High pressure cylinder 35 Suction pump

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Naohiko Chisato 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Inside the Toshiba Yokohama office

Claims (14)

[Claims] 1. A method for treating organic alkali wastewater, wherein the organic alkali is decomposed by keeping the wastewater containing the organic alkali in a supercritical state. 2. The method according to claim 1, wherein the supercritical state is a temperature of 374 ° C. or higher, a pressure of 22 MPa or higher, and a wastewater density of 328 kg / m 3 or higher. 3. When the waste water containing an organic alkali is brought into contact with an atmospheric gas or an aerated gas, the atmospheric gas or the aerated gas is a gas selected from air, nitrogen, helium, oxygen, and water vapor. The method for treating nitrogen-based organic alkali wastewater according to claim 1. 4. A wastewater containing an organic alkali, wherein a carboxylic acid, an oxidizing substance, hydrogen peroxide or ozone, or both of them, and a substance selected from aromatic compounds coexist. Method of treating nitrogenous organic alkali wastewater. 5. The nitrogen-based organic alkali according to claim 4, wherein the amount of said oxidizing substance is controlled to 0.7 to 5 times the amount of oxygen calculated from TOC of said nitrogen-based organic alkali wastewater. Waste liquid treatment method. 6. The nitrogen-based organic alkali wastewater according to claim 1, wherein the organic alkali-containing wastewater contains at least one of tetramethylammonium hydroxide and β-hydroxyethyltrimethylammonium hydroxide. Processing method. 7. A treatment vessel containing wastewater containing an organic alkali, wastewater introduction means for flowing and holding the wastewater containing the organic alkali into the treatment vessel, and a wastewater containing the organic alkali in the treatment vessel. In a nitrogen-based organic alkali wastewater treatment device having supercritical forming means for maintaining the supercritical state of the wastewater and wastewater deriving means for extracting the wastewater from the treatment vessel, wherein the wastewater introducing means and the wastewater deriving means include a valve. A nitrogen-based organic alkali wastewater treatment apparatus, wherein the wastewater is continuously treated by closing the valve at regular intervals. 8. The deriving means has a first valve and a second valve, and is controlled so as to close after taking out the waste water from the first valve, and thereafter to open the second valve. The apparatus for treating nitrogen-based organic alkali wastewater according to claim 6, wherein 9. The introduction means has a first pump for introducing the wastewater containing the organic alkali, and connects a second pump for introducing a liquid other than the wastewater to the processing vessel and the first pump in two stages. The apparatus for treating nitrogen-based organic alkali wastewater according to claim 7, wherein a high pressure is maintained by using a slurry pump. 10. The first valve, the second valve,
The apparatus according to claim 9, wherein the first pump and the second pump are controlled so that only one of the four pumps is opened to achieve a high pressure. . 11. An apparatus for treating nitrogen-based organic alkali wastewater according to claim 7, wherein said treatment vessel is filled with a catalyst. 12. The pH of the waste water containing the organic alkali.
The apparatus for treating nitrogen-based organic alkali wastewater according to claim 7, wherein is maintained at 10 to 4. 13. The processing vessel includes a pipe system for collecting gas generated inside and sending the gas to an adsorbent, and a pressurized vessel for collecting a single component gas separated from the adsorbent. The apparatus for treating nitrogen-based organic alkali wastewater according to claim 7, wherein: 14. The apparatus for treating a nitrogen-based organic alkali waste liquid according to claim 7, wherein said supercritical forming means has a heating means formed around said processing vessel.