JP2002355696A - Supercritical water oxidative decomposition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supercritical water oxidative decomposition apparatus for sewage sludge or the like capable of eliminating the defect of a conventional supercritical water oxidative decomposition apparatus for sewage sludge or the like and capable of being operated stably and continuously by preventing the adhesion of scale and suppressing pressure loss. SOLUTION: In the apparatus wherein organic matter containing inorganic matter is reacted with an oxidizing agent in supercritical water to be subjected to supercritical water oxidative decomposition, first and second preheating means 12a and 12b for preheating a mixed fluid to be treated are provided to the front stage of a reactor 10 and the first preheating means 12a preheats the mixed fluid to be treated to <200 deg.C and the flow passage 11a of the mixed fluid to be treated provided to the first preheating means 12a has a cross-sectional area for allowing the fluid mixture to be treated to flow at a flow speed with less pressure loss. The second preheating means 12b preheats the fluid mixture to be treated flowing out of the first preheating means to 200 deg.C or higher and the flow passage 11b of the fluid mixture to be treated provided to the second preheating means has a cross-sectional area allowing the fluid mixture to be treated to flow at a flow speed making it hard to adhere a scale component to the inner wall of the flow passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercritical hydroxylation / decomposition apparatus effective for preventing scale.

[0002]

2. Description of the Related Art Heretofore, as a method of oxidizing sewage sludge and the like, a method of mainly incineration has been generally used. However, since the sewage sludge has a high water content of 97 to 98%, in order to incinerate the sewage sludge, the sewage sludge is previously dehydrated by a dehydration means such as a screw press type dehydrator.
It was necessary to reduce the water content to the extent that it could be incinerated.

On the other hand, in recent years, a method of directly oxidizing sewage sludge using water in a supercritical state has been proposed.

[0004] However, when the sewage sludge is subjected to the supercritical water oxidation treatment, if the inorganic substances contained in the sludge settle as solids, there is a possibility that the pipe of the supercritical water oxidation apparatus may be clogged, and the supercritical water may be stably superposed. Oxidation treatment cannot be performed. To prevent blockage, ensure that solids do not settle,
It is necessary to make the flow velocity of the mixed fluid of the object to be processed at least a certain value. Therefore, the flow path of the fluid needs to have a certain thickness including the reactor.

[0005] Further, sewage sludge has a low concentration of organic substances contained therein and does not generate a large amount of heat. Therefore, in order to oxidize sewage sludge with supercritical water, it is necessary to preheat the sewage sludge.

Referring to FIG. 3, a conventional supercritical water oxidation apparatus for supercritical water oxidation of sewage sludge will be described. FIG. 3 is a flow sheet showing the configuration of a conventional supercritical water oxidation apparatus. As shown in FIG. 3, the conventional supercritical water oxidation apparatus 30 includes a tubular long pressure-resistant closed reactor 31 as a reactor for performing a supercritical water oxidation reaction, and upstream of the reactor 31, A sewage sludge pump 39 for supplying sewage sludge, an air compressor 40 for supplying oxygen, and a double-pipe heat exchanger 32 for preheating the reactants are provided downstream of the reactor 31 for heat exchange for cooling the reaction products. A device 33 and a cooler 34 are provided. When the reaction product is cooled by the heat exchanger 33, the heat medium becomes high in temperature, and is used as a heat source for preheating the mixed fluid to be processed by the double-tube heat exchanger 32. Further, the supercritical water oxidation device 30 includes a pressure control valve 35 for controlling the pressure in the reactor 31.
Downstream of the cooler 34, a gas-liquid separator 36 for gas-liquid separation of the reaction product into gas and slurry, downstream of the pressure control valve 35, and solid-liquid separation of the slurry-like reaction product, A solid-liquid separator 37 for separating inorganic solids from reaction products is provided. The inorganic solid separated by the solid-liquid separator 37 is
It is mainly contained in the reaction product and has not contributed to the reaction, and may additionally contain a salt generated by the supercritical hydroxylation reaction.

As shown in FIG. 3, the reactor including the preheating section is a pipe having substantially the same diameter.
2, a mixture to be treated of sewage sludge and oxygen flows through the inner tube, and a high-temperature heat medium flows through the outer tube.

In this case, the double tube heat exchanger 32 of the preheating section
Since a high-temperature heat medium flows through the outer tube, a thermal gradient is generated in the inner tube in the radial direction, and the temperature near the inner wall of the inner tube is the highest.

On the other hand, sewage sludge contains various scale components as inorganic substances. Among them, Ca salts and the like have a property of decreasing in solubility with increasing temperature and precipitating. Therefore, deposition of the scale component proceeds most on the inner wall of the inner tube. When the dissolved scale component precipitates on the inner wall of the pipe, it adheres to the inner wall of the pipe as a scale, and the pipe diameter decreases. Furthermore, the attached scale becomes a seed crystal,
Further, it promotes deposition and adhesion of scale components.

[0010] As described above, scale is easily formed and adhered in the preheating portion of the supercritical water oxidation apparatus, and as a result, the heat transfer efficiency is reduced and the pipe pressure loss is increased due to the decrease in the pipe diameter. It becomes difficult to continuously operate the critical water oxidation apparatus.

It is also conceivable to add a scale inhibitor to the sewage sludge, but when the scale inhibitor is added,
The generation of scale cannot be prevented only when the temperature at which the scale is generated slightly increases.

On the other hand, the scale in the preheating section can be suppressed by increasing the flow velocity. This is presumably because scale components that have not been fixed even when deposited near the wall surface are difficult to adhere to the tube wall as scale because the flow on the wall surface is disturbed by a large flow velocity.

However, if the flow velocity is increased, the pressure loss increases before the scale is attached, and the design pressure must be increased by the amount corresponding to the pressure loss.

As described above, the pressure loss increases when the scale is suppressed, and the scale is generated when the pressure loss is suppressed low, and in any case, the pressure loss is increased.

[0015]

The problem to be solved by the present invention is to overcome the drawbacks of the conventional supercritical water oxidation apparatus for sewage sludge and the like, to prevent the adhesion of scale and to suppress the pressure loss, and to stabilize it. It is an object of the present invention to provide a supercritical water oxidation apparatus for sewage sludge that can be continuously operated.

[0016]

The present inventors have studied the mechanism of scale formation in the method of supercritical water oxidation of sewage sludge.
It has been found that scale is intensively generated in a portion of about 0 ° C. to 350 ° C.

The scale is formed mainly by dissolving the scale component dissolved on the pipe wall. For scale components that have already been deposited, depending on their adhesion,
Since it is suspended as a suspension in the fluid, it does not easily adhere to the pipe as a scale. It is probable that almost all of the scale components were precipitated at around 350 ° C., so that they did not adhere to the inner tube wall as scale, and that scale formation was not remarkable at temperatures exceeding about 350 ° C.

The present invention has been made on the basis of the above-described findings, and is intended to suppress the heating by the first preheating means operating at a low pressure loss flow rate to less than 200 ° C., and then to preheat to 200 ° C. or more. It is characterized in that scale adhesion is prevented by operating at a high flow rate in the preheating means.

That is, in order to solve the above-mentioned problem, the present invention is directed to an apparatus for reacting an organic substance containing an inorganic substance and an oxidizing agent in supercritical water to supercritically decompose the organic substance. Object supply means for supplying water and an oxidizing agent at a pressure equal to or higher than the critical pressure of water, and a superposition of an object mixed fluid comprising an organic substance, water and an oxidizing agent pressurized and supplied from the object supply means. Supercritical water oxidation comprising a reactor for performing a critical hydroxylation reaction, cooling means for cooling the processed processing fluid flowing out of the reactor, and taking-out means for taking out the cooled processing fluid flowing out of the cooling means. A decomposition apparatus, comprising: a first preheating means and a second preheating means for preheating a mixed fluid to be treated in a stage preceding a reactor;
The preheating means preheats the temperature of the mixed fluid to be processed to less than 200 ° C., and the flow path of the mixed fluid to be provided provided in the first preheating means has a cross-sectional area where the mixed fluid flows at a flow rate with a small pressure loss. The second preheating means preheats the temperature of the mixed fluid flowing out of the first preheating means to 200 ° C. or more, and the flow path of the mixed fluid provided in the second preheating means has a scale component. The present invention relates to an apparatus for supercritically decomposing organic substances including inorganic substances, wherein the apparatus has a cross-sectional area in which a mixed fluid to be processed flows at a flow rate at which the mixed fluid hardly adheres to the inner wall of the flow path.

The present invention as set forth in claim 2 for solving the above-mentioned problems is directed to an apparatus for reacting an organic substance containing an inorganic substance and an oxidizing agent in supercritical water to supercritically decompose the organic substance. An object supply means for supplying water and an oxidizing agent at a pressure equal to or higher than the critical pressure of water; and a supercritical material mixed liquid comprising an organic substance, water and an oxidizing agent supplied under pressure from the object supply means. Supercritical hydroxylic decomposition provided with a reactor for performing a hydroxylation reaction, cooling means for cooling the processed processing fluid flowing out of the reactor and cooling means for taking out the cooled processing fluid flowing out of the cooling means A first preheating means, a second preheating means, and a third preheating means for preheating a mixed fluid to be treated in a stage preceding the reactor, wherein the first preheating means sets the temperature of the mixed fluid to be treated to 20;
The flow path of the mixed fluid to be treated, which is preheated to less than 0 ° C. and provided in the first preheating means, has a cross-sectional area in which the mixed fluid to be treated flows at a flow rate with a small pressure loss, and the second preheating means has the first preheating means. The temperature of the mixed fluid flowing out of the preheating means is set to 330 ° C.
The flow path of the mixed fluid to be treated, which is preheated to 350 ° C. and provided in the second preheating means, has a cross-sectional area in which the mixed fluid to be processed flows at a flow rate at which the scale component does not easily adhere to the inner wall of the flow path. The preheating means preheats the mixed fluid flowing out of the second preheating means to a temperature exceeding 350 ° C., and the flow path of the mixed fluid provided in the third preheating means is processed at a flow rate with a small pressure loss. The present invention relates to an apparatus for supercritically hydrolyzing an organic substance containing an inorganic substance, wherein the apparatus has a cross-sectional area through which a substance mixed fluid flows.

The present invention described in claim 3 for solving the above-mentioned problem is characterized in that the flow rate at which the scale component does not easily adhere to the inner wall of the flow path is 1.2 m / s or more. .

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The supercritical hydroxylation decomposition apparatus of the present invention is provided with a reactor for oxidatively decomposing organic substances including inorganic substances in the presence of supercritical water and an oxidizing agent. The supercritical hydroxylation reaction performed in the reactor is not particularly limited as long as the temperature and pressure conditions bring water into a supercritical state.
The temperature may be in the range of 00 to 650 ° C. and the pressure of 22 MPa or more, preferably 22 to 25 MPa. Examples of the oxidizing agent include air, pure oxygen, hydrogen peroxide, and liquid oxygen. These oxidizing agents may be used in a stoichiometrically required amount or more. The reactor for performing the supercritical hydroxylation decomposition may be any of a pipe (tubular) type and a vessel type.

Since water is a good solvent for organic substances and gaseous substances in the supercritical state, supercritical water, organic substances and oxidizing agent form a homogeneous phase in the reactor, and the supercritical water oxidation reaction The organic matter is oxidatively decomposed in a very short time.

The organic substance including the inorganic substance in the present invention is
For example, sewage sludge, factory waste liquid, pulp waste liquid and the like can be mentioned. Sewage sludge is mostly organic,
Contains about 20% of inorganic substances, the main components of which are Si,
It contains Al, Ca, P and the like.

The fluid to be treated in the present invention is a mixed fluid containing an organic substance containing an inorganic substance, an oxidizing agent and water, and may contain an auxiliary fuel and a scale inhibitor as required.

An embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) In a first embodiment, a first preheating means and a second preheating means are provided in a stage preceding a reactor for oxidizing an organic substance containing an inorganic substance in supercritical water, and the first preheating means is provided. Preheats the temperature of the mixed fluid to be processed to less than 200 ° C., and the flow path of the mixed fluid to be provided provided in the first preheating means has a cross-sectional area in which the mixed fluid flows at a flow rate with a small pressure loss. The second preheating means preheats the temperature of the mixed fluid flowing out of the first preheating means to 200 ° C. or more, and the flow path of the mixed fluid provided in the second preheating means has a scale component. Has a cross-sectional area in which the mixed fluid to be processed flows at a flow rate that is hard to adhere to the inner wall of the flow path.

In the temperature range of less than 200 ° C. in the first preheating means, the sludge has a high viscosity and the scale is hardly adhered.
The temperature of the mixed fluid flowing in the flow path changes due to a change in the flow rate or a change in the concentration of the processing object, and it is difficult to precisely control the temperature. Therefore, the term “less than 200 ° C.” in the present invention means that the temperature of the mixed fluid to be treated is approximately 2 ° C.
The temperature may be lower than 00 ° C., for example, 200 ± 2
The temperature may be lower than 0 ° C.

The flow path of the mixture fluid provided in the first preheating means has a cross-sectional area in which the mixture fluid flows at a flow rate with low pressure loss. The flow rate with a small pressure loss is a low flow rate that does not cause a pressure loss, and is, for example, 1.0 m / s or less, preferably 0.7 to 0.8 m / s (the flow rate in the present invention). Is the flow velocity when it is assumed that only the fluid to be processed is flowing in the normal temperature part, and the same applies hereinafter.) The cross-sectional area of the flow path of the fluid mixture to be processed provided in the first preheating means may be determined so as to have the above-mentioned flow velocity.

The temperature range of 200 ° C. or higher in the second preheating means is a temperature at which scale is easily generated. The second preheating means preheats from the outlet temperature of the first preheating means to a predetermined preheating temperature. The upper limit is not particularly limited, but may be preheated so that a predetermined temperature can be reached by reaction heat of the fluid to be treated. For example, in the case of sewage sludge with a sludge concentration of 10% and the reaction temperature is 550 ° C., the second
What is necessary is just to preheat to 350 degreeC with preheating means.

The flow path of the mixture fluid provided in the second preheating means has a cross-sectional area in which the mixture fluid flows at a flow rate at which the scale component does not easily adhere to the inner wall of the flow path. What is the flow rate at which the scale component is less likely to adhere to the inner wall of the flow path?
The flow velocity is relatively high, for example, 1.2 m / s or more.
The pipe diameter of the flow path of the mixed fluid to be processed provided in the second preheating means may be determined so as to have the above-mentioned flow velocity.

The method of preheating the mixed fluid to be treated by the first preheating means and the second preheating means is not particularly limited. For example, the heat of the processing fluid flowing out of the reactor may be recovered by a heat exchanger and used. .

As the first preheating means and the second preheating means, a double-pipe heat exchanger can be mentioned, and the cooling means provided at the latter stage of the reactor is also a double-pipe heat exchanger, and both are provided by piping. It is sufficient to perform heat exchange by connecting and flowing a heat medium to preheat the mixed fluid to be processed and cool the processed fluid after the reaction.

The first embodiment of the present invention will be described with reference to the flowchart of FIG.

As shown in FIG. 1, the supercritical water oxidation apparatus of the present invention includes a long tubular pressure-resistant closed reactor 10 as a reactor for performing a supercritical water oxidation reaction.
On the upstream side of the pressure source 0, a pressurized supply pump 26 as a pressurized supply unit for pressurizing and supplying a fluid to be treated such as sewage sludge to a pressure higher than the critical pressure of water, and a pressurized supply unit for pressurizedly supplying an oxidizing agent Pressurized supply pump 28 (a pressurized supply compressor when the oxidant is a gas such as oxygen) and a first preheater 12 of a double-pipe heat exchanger as preheating means for preheating the mixed fluid to be processed.
a and a second preheater 12b. Downstream of the reactor 10, a double-tube heat exchanger 14 and a cooler 16 for cooling the processed fluid after the reaction are provided. Further, the supercritical hydroxylation decomposition apparatus includes a pressure control valve 18 for controlling the pressure in the reactor 10 downstream of the cooler 16. As means for taking out the cooled processing fluid, a gas-liquid separator 20 for gas-liquid separation into gas and slurry is provided downstream of the pressure control valve 18,
Further, a solid-liquid separator 22 is provided which separates a solid reaction product from the reaction product by solid-liquid separation of the slurry reaction product. The inorganic solid separated by the solid-liquid separator 22 is mainly contained in the reaction product and has not contributed to the reaction, and may also contain a salt generated by the supercritical water oxidation reaction. is there.

First preheater 12a and second preheater 12b
Is a double-pipe heat exchanger including an inner pipe through which a mixed fluid of a processing object and an oxidant flows, and an outer pipe for heating the mixed fluid of the processing object.

In the first preheater 12a, the temperature of the mixed fluid to be processed is controlled to less than 200 ° C. in order to suppress the generation of scale. Since the mixed fluid to be processed in the flow path provided in the first preheater is controlled to a temperature at which scale is unlikely to be generated, it can flow at a low flow rate with a small pressure loss. Therefore, the cross-sectional area of the flow path 11a through which the mixed fluid to be processed flows may be determined so that the flow velocity of the mixed fluid to be processed is 1.0 m / s or less.

The fluid mixture to be processed, which has been preheated to less than 200 ° C. in the first preheater 12a,
Preheated to above 00 ° C. Since the scale is easily formed at 200 ° C. or higher, the mixed fluid to be processed flowing through the flow path 11b provided in the second preheater 12b needs to flow at a high flow rate at which the scale does not easily adhere to the inner wall in order to prevent adhesion of scale components. There is. Therefore, the cross-sectional area of the flow channel 11b may be determined so as to have a high flow rate (1.2 m / s or more) to which the scale component does not easily adhere.

The mixed fluid pretreated at 200 ° C. or higher in the second preheater 12 b is subjected to supercritical water oxidation in the reactor 10. In the case where the object to be treated is sewage sludge, etc., when the calorific value is insufficient and the temperature does not reach the critical temperature in the reactor 10, an organic substance as an auxiliary fuel is added to the object to be treated in advance, so that supercritical water oxidation proceeds. Good.

In supercritical water, in the presence of an oxidizing agent, organic substances in the object to be treated are quickly oxidized and decomposed into carbon dioxide, water and the like. A processing fluid consisting of decomposition products, inorganic substances and supercritical water flows out of the reactor 10.

A part of the heat of the high-temperature and high-pressure processing fluid is recovered by a double-tube heat exchanger 14 provided downstream of the reactor 10. Heat exchanger 14, first preheater 12a, second
The heat exchanger 12b is connected by a pipe 24, a heat medium is circulated, and the heated heat medium flowing out of the heat exchanger 14 is the second heat medium.
The mixed fluid supplied to the preheater 12b is heated to 200 ° C. or higher. The heat medium flowing out of the second preheater 12b is
The mixed fluid supplied to the first preheater 12a is
Preheat below 0 ° C.

The processing fluid from which a part of the heat has been recovered is cooled by the cooler 16 to room temperature. The cooled processing fluid is extracted as a processing liquid, an inorganic solid, and an exhaust gas by an extracting unit. Examples of the extracting means include a pressure control valve 18 for controlling the pressure of the cooled processing fluid, a gas-liquid separator 20 for separating the processing fluid released to the atmospheric pressure, and a solid-liquid separator 22.

By employing this embodiment, it is possible to efficiently suppress the generation of scale while suppressing the pressure loss.

(Second Embodiment) FIG. 2 shows a flowchart of a second embodiment of the present invention. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The difference between the second embodiment and the first embodiment is that the second preheater 12b for preheating to 200 ° C. or more
A third preheater 12c as a third preheating means for preheating to a temperature exceeding 350 ° C at a stage subsequent to the second preheater 12b '. The difference is that a flow path 11c having a cross-sectional area in which the mixed fluid to be processed flows at a flow rate with a small pressure loss is provided in 12c.

The second preheater 12b 'is set to a temperature of 200 to 350.degree.
In the flow path provided in the above, the mixture fluid to be processed flows at a high flow rate (1.2 m / s or more) in which the scale component is hard to adhere to the inner wall. The temperature of the mixture fluid to be processed flowing in the flow path is 200 to
It is difficult to strictly control the temperature to 350 ° C., and the temperature of 200 to 350 ° C. in the present invention is a temperature at which the temperature of the mixed fluid to be processed is approximately 200 to 350 ° C.
The temperature may be 0 ± 20 ° C. to 350 ± 35 ° C.

The provision of the third preheating means for preheating the mixed fluid to be processed to a temperature exceeding 350 ° C. is because at 350 ° C., almost all of the scale components are deposited at 350 ° C. This is because it does not adhere to the inner wall. The third preheating means preheats from the outlet temperature of the second preheating means to a predetermined preheating temperature. The upper limit is not particularly limited, but may be preheated so that a predetermined temperature can be reached by reaction heat of the fluid to be treated. For example, when the reaction temperature is set to 600 ° C. in the case of sewage sludge having a sludge concentration of 10%, the third preheating means may be preheated to 370 ° C.

[0048] In the third preheating means, the mixed fluid of the object to be treated is controlled to a temperature at which the scale is hardly deposited on the inner wall. Fluid can flow. The flow velocity with a small pressure loss is a low flow velocity that does not cause a pressure loss, and is, for example, 1.0 m / s or less, preferably 0.7 to 0.8 m / s. The cross-sectional area of the flow path of the fluid mixture to be processed provided in the third preheating means may be determined so as to have the above-mentioned flow velocity.

The third preheating means having a temperature exceeding 350 ° C. is provided, and the flow path of the third preheating means can have a cross-sectional area having a small pressure loss. Therefore, the pressure loss is further suppressed as compared with the first embodiment. be able to.

[0050]

According to the first aspect of the present invention, it is possible to efficiently suppress the formation of scale while suppressing the pressure loss, and to stably operate the supercritical hydroxylation and cracking apparatus for a long period of time.

According to the second aspect of the present invention, in addition to the above effects, the pressure loss can be further suppressed.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing a second embodiment of the present invention.

FIG. 3 is a flowchart showing a conventional supercritical water oxidation apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Reactor 11a, 11b, 11c Channel 12a First preheater 12b, 12b 'Second preheater 12c Third preheater 14 Heat exchanger 16 Cooler 18 Pressure control valve 20 Gas-liquid separator 22 Solid-liquid separator 24 Heat medium piping 26 Pressurized supply pump 28 Pressurized supply pump

Continued on the front page (72) Inventor Hiroshi Suzugaki 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Shinji Ito 1-2-8 Shinsuna, Koto-ku, Tokyo Organo Corporation (72) Inventor Akira Suzuki 1-2-2, Shinsuna, Koto-ku, Tokyo Organo Corporation F-term (reference) 4D059 AA05 AA30 BC01 BC02 BK30 DA44 DA47 EB06 EB20

Claims (3)

[Claims] In an apparatus for reacting an organic substance containing an inorganic substance and an oxidizing agent in supercritical water and supercritically decomposing the organic substance by supercritical water, the organic substance, water and the oxidizing agent are supplied under pressure higher than the critical pressure of water. A pressure supply means, a reactor for performing a supercritical hydroxylation reaction of the mixed fluid of the processing object comprising the organic substance, water and the oxidant supplied under pressure from the pressure supply means, and a reaction after the reaction flowing out of the reactor. What is claimed is: 1. A supercritical hydroxylation cracking apparatus comprising: a cooling means for cooling a processing fluid; and a takeout means for taking out a cooled processing fluid flowing out of the cooling means, wherein a mixed fluid to be processed is preheated at a stage preceding a reactor. A first preheating means and a second preheating means are provided, and the first preheating means preheats the temperature of the mixed fluid to be processed to less than 200 ° C. and the flow path of the mixed fluid provided to the first preheating means is Workpiece with low pressure loss flow rate A cross-sectional area through which the mixed fluid flows,
The second preheating means preheats the temperature of the mixed fluid flowing out of the first preheating means to 200 ° C. or more, and the flow path of the mixed processing fluid provided in the second preheating means has a scale component on the inner wall of the flow path. An apparatus for supercritically decomposing organic substances including inorganic substances, wherein the apparatus has a cross-sectional area in which a mixed fluid to be processed flows at a flow rate that is difficult to adhere to the substrate. 2. An apparatus for reacting an organic substance containing an inorganic substance and an oxidizing agent in supercritical water and supercritically decomposing the organic substance by supercritical water to supply the organic substance, water and the oxidizing agent under a pressure higher than the critical pressure of water. A pressure supply means, a reactor for performing a supercritical hydroxylation reaction of the mixed fluid of the processing object comprising the organic substance, water and the oxidant supplied under pressure from the pressure supply means, and a reaction after the reaction flowing out of the reactor. What is claimed is: 1. A supercritical hydroxylation decomposition apparatus comprising a cooling means for cooling a processing fluid and a take-out means for taking out a cooled processing fluid flowing out of the cooling means, wherein a mixed fluid to be processed is preheated at a stage preceding a reactor. A first preheating means, a second preheating means, and a third preheating means, wherein the first preheating means preheats the temperature of the mixed fluid to be processed to less than 200 ° C. and mixes the processing object provided in the first preheating means; Fluid flow path has low pressure loss The second preheating means preheats the temperature of the processing object mixed fluid flowing out of the first preheating means to 330 ° C. to 350 ° C. and supplies the second preheating means to the second preheating means. The flow path of the mixed fluid of the processing object provided has a cross-sectional area in which the mixed fluid of the processing object flows at a flow rate at which the scale component does not easily adhere to the inner wall of the flow path. 350 mixed fluids
The flow path of the mixed fluid to be treated, which is preheated to a temperature exceeding ℃ and provided in the third preheating means, has an inorganic material characterized by having a cross-sectional area in which the mixed fluid to be treated flows at a flow rate with a small pressure loss. Supercritical water oxidation decomposition equipment for organic substances. 3. The supercritical hydroxylation decomposition apparatus according to claim 1, wherein a flow rate at which the scale component hardly adheres to the inner wall of the flow channel is 1.2 m / s or more.