JP2002224680A - Method and apparatus for oxidizing organic liquid to be treated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for oxidizing an organic liquid to be treated, by which a toxic gas such as dinitrogen monoxide existing in a discharged gas can be removed. SOLUTION: This apparatus 1 for oxidizing the organic liquid to be treated is provided with a reactor 2 for decomposing/purifying the organic liquid A to be treated at high temperature under high pressure by oxidation reaction, a pressurizing and heating means for pressurizing and heating the liquid A and supplying the pressurized/heated liquid A to the reactor 2, a cooling and decompressing means for cooling and decompressing the treated liquid discharged from the reactor 2 and a gas-liquid separating tank 9 for separating the cooled/decompressed treated liquid into gas and liquid. An additionally installed heater 5 is provided with a discharged gas introducing route 10 for introducing the discharged gas separated in the tank 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic liquid to be treated, which decomposes and purifies an organic liquid to be treated containing various organic substances by oxidation under high temperature and high pressure, especially by supercritical or subcritical water oxidation. The present invention relates to an oxidation treatment method and apparatus.

[0002]

2. Description of the Related Art Utilizing the fact that even hardly decomposable harmful organic substances such as PCBs are rapidly and efficiently decomposed under high temperature and high pressure, especially in supercritical water, an organic liquid to be treated containing various organic substances can be superposed. 2. Description of the Related Art An oxidation treatment apparatus for an organic liquid to be treated, which is decomposed and purified by critical water oxidation or subcritical water oxidation (having lower efficiency than supercritical water oxidation and also called wet oxidation), has been developed.

As shown in FIG. 2, a conventional general organic treatment apparatus 20 for oxidizing a liquid to be treated includes a reactor 21, a high-pressure pump 22, a heat exchanger 23, a heater 24, and an oxidant supply means 2.
5, a cooler 26, a decompressor 27, a gas-liquid separation tank 28, and the like.

The reactor 21 is a cylindrical vessel or the like that causes an oxidation reaction of the organic liquid A under high temperature and high pressure (for example, in a supercritical state or a subcritical state). There are things. The high-pressure pump 22 pumps the organic treatment liquid A to the reactor 21 under high pressure. The heat exchanger 23 exchanges heat between the processing liquid discharged from the reactor 21 and the organic processing liquid A in order to effectively use the waste heat of the high-temperature processing liquid discharged from the reactor 21 to form an organic solution. The liquid A to be treated is preheated. The heater 24 heats the organic liquid A to be supplied to the reactor 21 to a desired temperature, and includes a heater, a burner, and the like. The oxidizing agent supply means 25 is for injecting an oxidizing agent such as oxygen or aqueous hydrogen peroxide that causes an oxidation reaction into the organic liquid A to be supplied to the reactor 21. The cooler 26 and the decompressor 27 cool and decompress the high-temperature and high-pressure processing liquid discharged from the reactor 21. The gas-liquid separation tank 28 separates the cooled and decompressed processing liquid into clean water B and exhaust gas C such as carbon dioxide generated by an oxidation reaction.

According to the apparatus 20 for oxidizing an organic liquid to be treated having the above-described structure, the organic liquid A is heated to a high temperature and a high pressure by the high-pressure pump 22, the heat exchanger 23 and the heater 24, and supplied to the reactor 21. At the same time, the oxidizing agent is supplied to the reactor 21 by the oxidizing agent supply means 25 to oxidize and decompose the organic matter in the organic treatment liquid A in the reactor 21.
6. Discharged as clean water B and exhaust gas C decomposed and purified by the decompressor 27 and the gas-liquid separation tank 28.

[0006]

According to the conventional apparatus 20 for oxidizing an organic liquid to be processed, the organic liquid A containing various organic substances is converted into carbon dioxide, nitrogen, water, organic salts, and the like. It is almost completely decomposed, but when the device is not in a steady state such as at the start of operation, at the end of operation, at the time of change in operating conditions, or at the time of occurrence of an abnormality, harmful gas such as nitrous oxide (N ₂ O) is emitted. There is a risk of mixing in C. In particular, when nitric acid is used as a strong oxidizing agent in order to rapidly decompose the nitrogen-containing substance contained in the organic liquid A, the harmful gas is easily generated.

The present invention has been made in view of these problems, and has as its object to provide a method and an apparatus for oxidizing an organic liquid to be treated which can remove harmful gases such as nitrous oxide present in exhaust gas. It is assumed that.

[0008]

Means for Solving the Problems The invention made to solve the above-mentioned problems comprises a reaction step of decomposing and purifying an organic liquid to be treated by an oxidation reaction at a high temperature and a high pressure; A pressurization / heating step in which the liquid to be treated is pressurized and heated, and a cooling / cooling step in which the treatment liquid after the reaction step is cooled / depressurized
A method for oxidizing an organic liquid to be treated, comprising a decompression step and a gas-liquid separation step of gas-liquid separation of the treatment liquid, wherein an exhaust gas separated in the gas-liquid separation step is introduced into an attached heater. Exhaust gas introducing step.

According to the method for oxidizing an organic liquid to be treated, the exhaust gas separated in the gas-liquid separation step in the exhaust gas introduction step is introduced into the heater. The harmful gas components such as nitrous oxide can be decomposed at high temperature, and the exhaust gas can be made harmless.

In the method for oxidizing an organic liquid to be treated, a heater is used for heating the organic liquid to be treated in the pressurizing / heating step, and a heater for introducing an exhaust gas in the exhaust gas introducing step is added. It is preferable to use a heater for the pressure / heating step.
According to this means, the existing heater is effectively used in the pressurization / heating step for the high-temperature decomposition of the harmful gas components in the exhaust gas, and the exhaust gas treatment as in the conventional oxidation treatment method of the organic liquid to be treated is performed. It is possible to improve the economic efficiency without requiring any additional device.

Preferably, a burner is used as the heater, and the exhaust gas is introduced into the combustion flame of the burner in the exhaust gas introducing step. According to this means, nitrous oxide and the like in the exhaust gas can be decomposed at a high temperature by the combustion flame of the burner, and can be easily and quickly made harmless, and the exhaust gas is introduced into a large amount of the burner gas. In addition, the reduction of the concentration of the exhaust gas component and the diffusion effect are promoted.

The oxidation reaction in the above reaction step includes:
Supercritical or subcritical hydroxylation is preferred. According to such supercritical water oxidation (SCWO) or subcritical water oxidation, the organic liquid to be treated containing various organic substances can be quickly and completely decomposed and purified. In an unsteady state such as time, harmful gases such as carbon monoxide and nitrous oxide are likely to be mixed into the exhaust gas,
The method for oxidizing the organic liquid to be treated having the exhaust gas introduction step is effective.

Further, an invention of an apparatus made to solve the above-mentioned problem is directed to a reactor for decomposing and purifying an organic liquid to be treated by an oxidation reaction at a high temperature and a high pressure; A pressurizing / heating means for supplying a liquid by pressurizing and heating, a cooling / depressurizing means for cooling / depressurizing the processing liquid discharged from the reactor, and a gas-liquid separation tank for separating the processing liquid into gas and liquid. An apparatus for oxidizing an organic liquid to be treated, comprising an exhaust gas introduction path for introducing exhaust gas separated in the gas-liquid separation tank to an attached heater.

According to the apparatus for oxidizing an organic liquid to be treated, the exhaust gas separated in the gas-liquid separation tank by the exhaust gas introduction path is supplied to the heater, similarly to the method for oxidizing the organic liquid to be treated. Once introduced, harmful gas components such as nitrous oxide in the exhaust gas can be decomposed at high temperature and detoxified by using the heat of the heater.

Further, for the same reason as in the above-mentioned method for oxidizing the organic liquid to be treated, (a) a heater is used for heating the organic liquid to be treated in the pressurizing / heating means, and the exhaust gas is introduced. The heater for introducing the exhaust gas through the passage may be a heater of the pressurizing / heating means. (B) A burner may be used as the heater, and the exhaust gas may be introduced into the combustion flame of the burner through the exhaust gas introduction passage. (C) As the oxidation reaction in the reactor, supercritical water oxidation or subcritical water oxidation is preferable.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings as appropriate. FIG. 1 is a schematic configuration diagram showing an apparatus for oxidizing an organic liquid to be treated according to an embodiment of the present invention.

FIG. 1 shows an apparatus 1 for oxidizing an organic liquid to be treated.
Comprises a reactor 2, a high-pressure pump 3, a heat exchanger 4, a heater 5, an oxidant supply means 6, a cooler 7, a decompressor 8, and a gas-liquid separation tank 9 in the same manner as the above-mentioned conventional oxidation treatment apparatus 20. And an exhaust gas introduction path 10 is additionally provided. The high-pressure pump 3, the heat exchanger 4, and the heater 5
Correspond to the pressurizing / heating means, and include a cooler 7 and a decompressor 8
Corresponds to the cooling / decompression means.

The high-pressure pump 3 is for pumping the organic liquid to be treated A stored in a raw material tank or the like to the reactor 2 (corresponding to the above-mentioned pressurizing means), for example, a plunger type pump, a diaphragm type pump, A screw pump or the like is used.

The heat exchanger 4 exchanges heat between the treatment liquid discharged from the reactor 2 and the organic treatment liquid A, and preheats the organic treatment liquid A with a high-temperature and high-pressure treatment liquid. .
As the heat exchanger 4, a general heat exchanger for high temperature resistance and high pressure resistance can be used. However, in consideration of using a high temperature, high pressure and high concentration liquid as a working fluid, 2
Double tube heat exchangers are preferred.

The heater 5 is for heating the organic liquid A to be sent to the reactor 2 to a predetermined oxidation reaction temperature, and the heat source is not particularly limited. , Combustion gas and the like can be used.

The organic liquid A is heated and pressurized to a predetermined temperature and pressure by the high-pressure pump 3, the heat exchanger 4 and the heater 5 and supplied to the reactor 2.

The reactor 2 is for decomposing and purifying an organic substance in the organic treatment liquid A by causing an oxidation reaction under a high temperature and a high pressure (for example, a supercritical state or a subcritical state). The type of the reactor 2 is not particularly limited, and a general reactor for high temperature resistance and high pressure resistance can be used, but the organic treatment liquid A is continuously decomposed. In consideration of the above, a tubular reactor is preferred. The reactor 2
As the temperature and pressure inside, 200 ℃ ～ 650 ℃, 5MP
a to 30 MPa, preferably 400 ° C. to 600 ° C., 22
Supercritical water oxidation of 30 MPa to 30 MPa is particularly preferred in view of the speed and completeness of the reaction.

The oxidizing agent supply means 6 is for injecting an oxidizing agent into the organic processing liquid A in order to cause an oxidation reaction to an organic substance in the organic processing liquid A in the reactor 2. Oxygen is used as an oxidizing agent in the oxidizing treatment apparatus 1 for the liquid to be treated, and a pump 11 for pumping liquid oxygen D under pressure is used.
And an evaporator 12 for vaporizing the liquid oxygen D. As the oxidizing agent, air other than oxygen, hydrogen peroxide, or the like can be used as long as it has an oxidizing power for organic substances. As the oxidizing agent supply unit 6 by the oxidizing agent supplying means 6, the entire amount necessary for decomposing the organic substance in the organic liquid A to be treated may be injected immediately before the reactor 2 or may be injected immediately before the reactor 2. It may be supplied separately to an appropriate position in the reactor 2.

The cooler 7 is for cooling the high-temperature and high-pressure processing liquid discharged from the reactor 2, and a general cooler such as an air cooler can be used. In addition,
It is also conceivable to effectively use waste heat by cooling with a refrigerant.

The pressure reducer 8 is for reducing the pressure of the high-temperature and high-pressure processing liquid discharged from the reactor 2 and generally uses a pressure reducing valve or the like. The decompressor 8 and the cooler 7 correspond to the above-described cooling / decompression means.

The gas-liquid separation tank 9 is a tank for separating the processing liquid discharged from the reactor 2 into clean water B decomposed and decomposed gas C such as carbon dioxide and nitrogen generated by an oxidation reaction of organic substances. is there.

The exhaust gas introduction path 10 is a conduit or the like for guiding the exhaust gas C separated in the gas-liquid separation tank 9 to the heater 5.
The exhaust gas C separated in the gas-liquid separation tank 9 by the exhaust gas introduction path 10 is guided to the heater 5 and heated by the heater 5, and as a result, harmful gases such as nitrous oxide in the exhaust gas C The components can be decomposed at high temperature and made harmless. Therefore, the apparatus 1 for oxidizing the organic liquid to be treated can discharge the detoxified exhaust gas C ′ by using the existing heater 5 without providing a special exhaust gas processing apparatus.

The function of the apparatus 1 for oxidizing an organic liquid to be treated having the above structure will be described below. First, the organic processing liquid A is supplied to the reactor 2 by pressurizing and heating by the high-pressure pump 3, the heat exchanger 4, and the heater 5 of the pressurizing and heating means. When the oxidizing agent is supplied into the liquid A to be treated, the organic substance is oxidized and decomposed in the reactor 2 by an oxidation reaction between the organic substance in the liquid A to be treated and the oxidizing agent.
Thereafter, the processing liquid discharged from the reactor 2 is cooled and decompressed by the coolers 7 and 8 of the cooling / decompression means, is separated into gas and liquid by the gas-liquid separation tank 9, and is discharged to the outside. Through such a process, the organic treatment liquid A containing an organic substance is decomposed and purified. The oxidation treatment apparatus 1 for the organic treatment liquid uses the exhaust gas introduction path 10 as described above. The exhaust gas C separated in the liquid separation tank 9 is guided to the heater 5, and the heat of the existing heater 5 is used to decompose harmful gas components such as nitrous oxide in the exhaust gas C at a high temperature to make them harmless. can do.

It is preferable to use a burner as the heater 5, and to introduce the exhaust gas C into the combustion flame of the burner through the exhaust gas introduction path 10. According to this means,
The combustion flame of the burner can quickly and almost completely decompose nitrous oxide and the like in the exhaust gas C at a high temperature.
Since the exhaust gas C is introduced into a large amount of the burner gas, the concentration of the exhaust gas component is reduced and the gas diffusion action is promoted.

The oxidation treatment of the organic liquid to be treated of the present invention is not limited to the above embodiment. For example, the exhaust gas C separated in the gas-liquid separation tank 9 by the exhaust gas introduction path 10 is It is also possible to introduce into a separately provided heater instead of the heater 5 of the pressurizing / heating means.

[0031]

As described above, according to the method and apparatus for oxidizing an organic liquid to be treated according to the present invention, exhaust gas detoxified by high-temperature decomposition of nitrous oxide or the like by a heater is discharged. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an apparatus for oxidizing an organic liquid to be treated according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a conventional general apparatus for oxidizing an organic liquid to be treated.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oxidation treatment apparatus 2 Reactor 3 High pressure pump 4 Heat exchanger 5 Heater 6 Oxidant supply means 7 Cooler 8 Decompressor 9 Gas-liquid separation tank 10 Exhaust gas introduction path 11 Pump 12 Evaporator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiyuki Sora 2-274, Obatani-cho Kohata, Nishi-ku, Kobe-shi, Hyogo (72) Inventor Mamoru Miyagawa 7-13-21, Uozakiminami-cho, Higashinada-ku, Hyogo Kaoru Muraoka 1-16-10 Kokubo Akashi, Hyogo Prefecture Ansel Mo Nishiakashi 502 F-term (reference) 4D002 AA12 AC10 BA05 CA20 EA20 4D050 AA12 BB01 BC01 BC02 BD03 BD06

Claims (8)

[Claims] 1. A reaction step for decomposing and purifying an organic liquid to be treated by an oxidation reaction under high temperature and high pressure, and pressurizing and heating to supply the organic liquid to be treated by pressurizing and heating in this reaction step. A method for oxidizing an organic liquid to be treated, comprising: a step; a cooling / depressurizing step of cooling / depressurizing the treatment liquid after the reaction step; and a gas / liquid separation step of gas / liquid separation of the treatment liquid. An exhaust gas introducing step of introducing the exhaust gas separated in the gas-liquid separation step into the heater. 2. A heater for heating an organic liquid to be treated in the pressurizing / heating step, wherein a heater for introducing an exhaust gas in the exhaust gas introducing step is a heater in the pressurizing / heating step. Item 4. The method for oxidizing an organic liquid to be treated according to Item 1. 3. The method for oxidizing an organic liquid to be treated according to claim 1, wherein a burner is used as the heater, and an exhaust gas is introduced into the combustion flame of the burner in the exhaust gas introducing step. . 4. The method for oxidizing an organic liquid to be treated according to claim 1, wherein the oxidation reaction in the reaction step is supercritical water oxidation or subcritical water oxidation. 5. A reactor for decomposing and purifying an organic liquid to be treated by an oxidation reaction at high temperature and high pressure, and pressurizing and heating the organic liquid to be treated by pressurizing and heating the reactor. Means, a cooling / depressurizing means for cooling / depressurizing the processing liquid discharged from the reactor, and a gas-liquid separation tank for separating the processing liquid into a gas and a liquid. An apparatus for oxidizing an organic liquid to be treated, characterized in that an attached heater is provided with an exhaust gas introduction path for introducing the exhaust gas separated in the gas-liquid separation tank. 6. A heater for heating the organic liquid to be treated in the pressurizing / heating means, wherein the heater for introducing exhaust gas in the exhaust gas introduction path is a heater of the pressurizing / heating means. The apparatus for oxidizing an organic liquid to be treated according to claim 5. 7. The apparatus for oxidizing an organic liquid to be treated according to claim 5, wherein a burner is used as the heater, and the exhaust gas is introduced into the combustion flame of the burner through the exhaust gas introduction path. . 8. The apparatus for oxidizing an organic liquid to be treated according to claim 5, wherein the oxidation reaction in the reactor is supercritical water oxidation or subcritical water oxidation.