JP2003299942A - Hydrothermal reaction treatment method and apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrothermal reaction treatment apparatus capable of preventing at least the corrosion of a reaction container due to a salt. <P>SOLUTION: In the hydrothermal reaction treatment apparatus wherein a substance to be treated is subjected to hydrothermal oxidation reaction in a reaction container 21 held to a supercritical or sub-critical state to be treated, the reaction container 21 or at least a part of the parts therein is coated with at least one compound selected from an alkali metal or alkaline earth metal oxide, sulfate, carbonate or hydrogencarbonate or coated with a salt formed by supplying a solution of an alkali metal or alkaline earth metal salt of an organic acid under a hydrothermal oxidative reaction condition. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention prevents corrosion of a reaction vessel which causes a hydrothermal oxidation reaction for the purpose of waste decomposition, energy generation or chemical substance production in a supercritical or subcritical state of water. The present invention relates to a reduced hydrothermal reaction treatment method and apparatus.

[0002]

2. Description of the Related Art Hydrothermal reaction treatment for decomposing waste, generating energy, or producing chemical substances by treating an object to be treated and oxidatively decomposing or hydrolyzing has been conducted for many years. It has been studied and used throughout. In particular, in recent years, in a supercritical state of 374 ° C. or higher and 22.1 MPa (220 atm) or higher, or, for example, 374 ° C. or higher, 2.5 MPa (25 atm) or higher and less than 22.1 MPa, or less than 374 ° C., 22.1 MPa. Hydrothermal oxidation by reacting the object to be treated with water containing an oxidant in the subcritical state, which is a high temperature and high pressure state close to the critical point even if the temperature is less than or equal to 374 ° C. or less than 22.1 MPa. Attention has been focused on a hydrothermal oxidation reaction treatment which causes a reaction and almost completely decomposes an organic substance in an object to be treated.

When the object to be treated is oxidatively decomposed by the hydrothermal oxidation reaction treatment, the object to be treated, the oxidizing agent and water are heated and pressurized and supplied into the reaction vessel for reaction. Then, as a result of the hydrothermal oxidation reaction treatment, the organic matter is oxidatively decomposed to obtain a high-temperature high-pressure fluid composed of water and carbon dioxide, and a reaction product composed of a solid such as ash and salts in a dried or slurry form.

When the object to be treated is subjected to the hydrothermal oxidation reaction as described above, the reaction vessel is corroded by the acid contained in the object to be treated or generated by the hydrothermal oxidation reaction or by the alkali. Is becoming a big problem.

Therefore, as disclosed in, for example, JP-A-3-500264, before supplying a sufficient amount of neutralizing agent to neutralize the acid generated from the object to be treated into the reaction vessel. The acid or alkali is converted into a neutralized salt in the reaction vessel.

[0006]

However, even if the object to be treated to which the neutralizing agent has been added is subjected to the hydrothermal reaction, the reaction vessel may be corroded depending on the composition of the salt. It is necessary to prevent or reduce the corrosion of the container.

The present invention has been made by paying attention to the points described later, and provides a hydrothermal oxidation treatment method and apparatus capable of preventing or reducing at least the corrosion of a reaction vessel by salt. is there.

[0008]

First, the invention according to claim 1 is a hydrothermal reaction in which an object is treated by a hydrothermal oxidation reaction in a reaction vessel in which water is in a supercritical state or a subcritical state. In the treatment method, before starting the hydrothermal oxidation reaction of the object to be treated, at least a part of the reaction vessel or parts in the reaction vessel is treated with an alkali metal or alkaline earth metal oxide, sulfate, carbonate or It is characterized by coating with at least one selected from carbon hydrogen salts. The invention according to claim 2 is a hydrothermal reaction treatment method of treating a substance to be treated by hydrothermal oxidation reaction in a reaction vessel in which water is in a supercritical state or a subcritical state. Before starting the thermal oxidation reaction, a liquid containing an alkali metal or alkaline earth metal salt of an organic acid is supplied to the reaction vessel or at least a part of the parts inside the reaction vessel under hydrothermal oxidation reaction conditions to generate It is characterized by coating with a salt. Further, the invention according to claim 3 is characterized in that, in the hydrothermal reaction treatment method according to claim 1 or 2, the treatment liquid of the hydrothermal oxidation reaction is analyzed to monitor the state of corrosion. . Next, the invention according to claim 4 is a hydrothermal reaction treatment apparatus for treating a material to be treated by a hydrothermal oxidation reaction in a reaction vessel in which water is in a supercritical state or a subcritical state. Or at least a part of the parts in the reaction vessel is coated with at least one selected from oxides, sulfates, carbonates or carbon hydrogen salts of alkali metals or alkaline earth metals. The invention according to claim 5 is a hydrothermal reaction treatment apparatus for treating a material to be treated by a hydrothermal oxidation reaction in a reaction vessel in which water is in a supercritical state or a subcritical state. At least a part of the parts in the reaction vessel is characterized in that a liquid containing an alkali metal salt or an alkaline earth metal salt of an organic acid is supplied under a hydrothermal oxidation reaction condition and is coated with a salt produced. Further, claim 6
The invention described in (4) is characterized in that, in the hydrothermal reaction treatment apparatus of (4) or (5), means for analyzing the treatment liquid of the hydrothermal oxidation reaction and monitoring the state of corrosion is provided. The parts in the reaction vessel referred to in the present invention refer to a scraper for scraping off the salt accumulated in the reaction vessel, various nozzles for supplying quench water, and the like.

The present invention is based on the following points of interest. Sodium sulfate, sodium carbonate, sodium hydrogencarbonate, alkaline earth metal oxides (eg magnesium oxide, calcium oxide), alkaline earth metal sulfates (eg magnesium sulfate, calcium sulfate), alkaline earth metal carbonates Salts (eg magnesium carbonate, calcium carbonate), hydroxides of alkaline earth metals (eg magnesium hydroxide, calcium hydroxide) (hereinafter, these salts will be referred to as “corrosion inhibiting salts” as necessary).
Is written. ) Has a low solubility in a supercritical state or a subcritical state of water (both states are also referred to as “under hydrothermal oxidation environment”), and is not easily discharged when precipitated. Further, the corrosion-inhibiting salt has a very small corrosiveness in a hydrothermal oxidation environment. Furthermore, when the corrosion-inhibiting salt is attached, the corrosion caused by the treatment liquid is significantly reduced. Further, when an alkali metal salt or alkaline earth metal salt of an organic substance is subjected to a hydrothermal oxidation reaction, a carbonate or oxide of the metal is produced, and the same effect as the above corrosion inhibiting salt is achieved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a hydrothermal oxidation treatment apparatus which is an embodiment of the present invention.

In FIG. 1, 1 is a treatment object storage tank for storing a waste liquid as a treatment object, 2 is a supply pipe for supplying the waste liquid in the treatment object storage tank 1 into a reaction vessel 21 described later, and 3 is a supply pipe. An on-off valve 4 arranged on the pipe 2 is a high-pressure liquid feed pump arranged on the supply pipe 2 upstream of the on-off valve 3, and the high-pressure liquid feed pump 4 discharges waste liquid, for example, 2.5 MPa ( It is supplied into the reaction vessel 21 at a high pressure (25 atm) or higher. Reference numeral 5 is an auxiliary fuel storage tank for storing auxiliary fuel, 6 is a supply pipe for supplying the auxiliary fuel in the auxiliary fuel storage tank 5 into the supply pipe 2 downstream of the on-off valve 3, and 7 is arranged in the supply pipe 6. The high pressure pump 7 supplies the auxiliary fuel into the supply pipe 2 at a high pressure of, for example, 2.5 MPa (25 atm) or higher.

Reference numeral 8 is a water tank for storing water, 9 is a supply pipe for supplying the water in the water tank 8 into the supply pipe 2 downstream of the on-off valve 3.
Reference numeral 10 denotes a high-pressure liquid feed pump arranged in the supply pipe 9, and the high-pressure liquid feed pump 10 supplies water, for example, 2.5 MPa.
It is supplied into the supply pipe 2 at a high pressure (25 atm) or more. Reference numeral 11 denotes a supply pipe for supplying the water in the water tank 8 as quench water into the reaction vessel 21, and 12 denotes a high-pressure liquid supply pump arranged in the supply pipe 11, and the high-pressure liquid supply pump 12 has
Water is supplied into the reaction vessel 21 at a high pressure of, for example, 2.5 MPa (25 atm) or higher.

Reference numeral 13 denotes an air compressor, which supplies air as an oxidant into the supply pipe 2 downstream of the on-off valve 3 via the supply pipe 14 at a high pressure of, for example, 2.5 MPa (25 atm) or more. It is a thing. Reference numeral 15 denotes a preheater arranged in the supply pipe 14, which is an air compressor 1
The air from 3 is preheated to a predetermined temperature.

Reference numeral 16 denotes a storage tank for storing a liquid containing at least one kind of corrosion-inhibiting salt (hereinafter referred to as "corrosion-inhibiting salt solution"), and 17 denotes the corrosion-inhibiting salt solution in the storage tank 16 from the on-off valve 3. Supply pipe for supplying into the supply pipe 2 downstream, 18 is the supply pipe 1
7 is an on-off valve, and 19 is a high-pressure liquid feed pump provided on the supply pipe 17 upstream of the on-off valve 18. This high-pressure liquid feed pump 19 is a corrosion-inhibiting salt liquid, for example, 2. 5M
It is supplied into the supply pipe 2 at a high pressure of Pa (25 atm) or higher.

Reference numeral 21 denotes a cylindrical vertical reaction vessel, which is provided with a nozzle 25 (see FIG. 2) for ejecting waste liquid or the like supplied from the supply pipe 2 at the center of the upper lid, and the processing liquid on the lower side. A discharge port 24a for discharging the is provided. In addition,
When the nozzle 25 is provided so as to protrude from the upper lid by 4 cm or more,
Accumulation of salts in the reaction vessel 21 is reduced, which is preferable.

Reference numeral 51 denotes a discharge pipe connected to the discharge port 24a of the reaction vessel 21, and 52 denotes a cooler arranged in the discharge pipe 51. This cooler 52 is the discharge port 24a of the reaction vessel 21.
It cools the processing liquid discharged from the. Reference numeral 53 denotes a gas-liquid separator connected to the discharge pipe 51, which separates the processing liquid supplied from the discharge pipe 51 into a gas and a liquid. 54 is a gas discharge pipe connected to the gas-liquid separator 53,
Reference numeral 55 denotes a pressure reducing valve arranged in the gas discharge pipe 54, and this pressure reducing valve 55 decompresses and releases the gas separated by the gas-liquid separator 53. Reference numeral 56 indicates a liquid discharge pipe connected to the gas-liquid separator 53, and 57 indicates a pressure reducing valve arranged on the liquid discharge pipe 56. The pressure reducing valve 57 is a liquid level height of the liquid separated by the gas liquid separator 53. The liquid is discharged so as to keep the height constant.

FIG. 2 is a sectional view showing a schematic structure of the reaction container shown in FIG.

In FIG. 2, the reaction vessel 21 has a cylindrical portion 22 in which a cylindrical space for reaction is formed, and the lower end portion is funnel-shaped and narrows toward the center. It is arranged on the inner surface for the purpose of protecting from corrosion.
It is composed of a liner 23 made of titanium or the like and a base 24 on which the cylindrical portion 22 is placed. The nozzle 25 connected to the supply pipe 2 is arranged in the central portion of the upper lid of the cylindrical portion 22 in the axial direction of the cylindrical portion 22, and the nozzle 25 is provided below the cylindrical portion 22 via the supply pipe 11. A quench water supply hole 22a for supplying the supplied water (quenching water) to the lower side of the space portion of the cylindrical portion 22 is provided, and an upper portion of the base 24 is provided from the lower side of the space portion of the cylindrical portion 22. A discharge port 24a for discharging the processing liquid to the discharge pipe 51 is provided, and the base 24
An opening 24b into which a chain 42 of a drive mechanism 41, which will be described later, is inserted is provided in the lower side portion.

Reference numeral 31 denotes a scraper, which is rotatably disposed on the base 24 and has a rotating shaft 32 having an upper portion projecting to the lower side of the cylindrical portion 22, and a rotary shaft 32 attached to the upper portion of the rotating shaft 32 and having a surface of the liner 23. The scraper main body 33 is made of a nickel-based alloy or the like and is formed to scrape off the salt and the like adhering to the scraper. In addition, the opening 2 of the rotary shaft 32
A gear that meshes with the chain 42 of the drive mechanism 41 is provided on the peripheral surface having a height corresponding to 4b. The above-mentioned scraper body 33 is a rod-shaped one that is attached around the rotating shaft 32 at a predetermined interval, for example, at 60-degree intervals, or is cylindrical and has a plurality of openings on the cylindrical surface to form blades. What was done can be used.

Reference numeral 41 denotes a drive mechanism, which is composed of a motor arranged outside the reaction vessel 21 and a chain 42 stretched between the motor and the gear of the rotary shaft 32 and arranged in the opening 24b. There is. And each part is sealed by the sealing material.

Next, an example of coating a salt to form a protective film will be described, and then the hydrothermal oxidation treatment will be described. First, the on-off valves 3 and 18 are closed, and the high pressure liquid feed pump 4 and
The high-pressure liquid-sending pumps 10 and 12, excluding 19, the high-pressure pump 7, the air compressor 13, and the preheater 15 are operated to supply auxiliary fuel or the like into the reaction vessel 21 to cause a hydrothermal oxidation reaction to cause the reaction vessel. The inside of 21 is raised to a predetermined temperature. Then, the high-pressure liquid feed pump 19 is operated and the opening / closing valve 18 is opened to supply the corrosion-inhibiting salt solution in the storage tank 16 into the reaction vessel 21.

When the corrosion-inhibiting salt solution is supplied into the reaction vessel 21 as described above, the salt has a low solubility in a hydrothermal oxidizing environment, so that it precipitates and adheres to the surface of the liner 23 or the like to form a protective film. To do. This is continued for a predetermined time. Then, after forming a protective film having a predetermined thickness, the high-pressure liquid feed pump 4
Is operated and the on-off valve 3 is opened to start the supply of waste liquid. At this time, while gradually reducing the supply amount of the corrosion inhibiting salt solution, the supply amount of the waste liquid is gradually increased to a predetermined amount. Then, when the supply amount of the corrosion-inhibiting salt solution becomes sufficiently small, the high-pressure liquid feed pump 19 is stopped and the on-off valve 18 is closed. The waste liquid undergoes a hydrothermal oxidation reaction in the reaction vessel 21, and the reaction product is discharged from the discharge port 24a.

When this operation is continued, the amount of salt adhering to the inside of the reaction vessel 21 increases and the reaction region becomes narrower as the operating time elapses, or salt and reaction products accumulate below the reaction vessel 21. Therefore, when the drive mechanism 41 rotates the scraper 31 at a low speed (for example, 8 rpm) during operation, the rotating scraper body 33 scrapes off the salt adhering to the surface of the liner 23 in the reaction vessel 21 and rotates the rotating shaft. The reaction product is crushed and agitated by the fins 32a of 32 so as to be easily discharged, and is conveyed toward the discharge port 24a.

Further, the water supplied to the quench water supply hole 22a dissolves a part of the accumulated salt, slurries the salt or the reaction product, and even if the salt or the reaction product is not dissolved, it is in the form of particles or powder. Fluidized salt and reaction products,
It is conveyed to a and discharged to the gas-liquid separator 53 as a processing liquid. Then, the treatment liquid supplied to the gas-liquid separator 53 is separated into a gas and a liquid, and the separated gas is decompressed by the decompression valve 55, and then discharged through the gas discharge pipe 54, and the separated liquid. Is decompressed by the decompression valve 57, and then the liquid discharge pipe 56
Is discharged through.

While the waste liquid is hydrothermally oxidized in this way, the properties of the liquid discharged from the liquid discharge pipe 56 are analyzed, and the reaction container 21 and the scraper body 33 are constituted without being included in the waste liquid, for example. Measure the amount of chromium and nickel. If these are detected, it is considered that the corrosion has progressed, and it is necessary to coat the protective film again.

When the protective film is to be provided again, the hydrothermal oxidation treatment of the waste liquid is stopped, the inside of the reaction vessel 21 is washed with water to remove salts and the like, and then the corrosion-inhibiting salt solution is added to the reaction vessel as described above. 21 and the hydrothermal oxidation reaction may be performed.
The cleaning conditions (temperature, amount of water, cleaning time, etc.) at this time are
It may be carried out under optimum conditions according to the attached salts.

The present invention is preferably carried out in a vertical cylinder type reaction vessel in which the liquid to be treated is supplied by a spray nozzle. And
By using the spray nozzle, the material for coating can be uniformly and finely dispersed, and the inside of the reaction vessel can be efficiently coated. Further, in a reaction vessel having a small inner diameter such as a tube type reaction vessel, it becomes easy to close it by coating, and in a horizontal type reaction vessel, the entire surface cannot be uniformly coated, and it is unevenly deposited on the lower surface side. There's a problem. As the shape of the reaction container, a vertical cylindrical reaction container having an inner diameter of 50 mm or more is suitable.

Next, examples will be described. First, 6
An aqueous solution or suspension of a corrosion inhibiting salt is supplied into the reaction vessel 21 at 50 ° C. for 1 hour to form a protective film. The concentration of the corrosion inhibiting salt was adjusted so that each corrosion inhibiting salt was 1 wt% in terms of carbonate.

The waste liquid shown in Table 1 was hydrothermally oxidized for 4 hours under the conditions shown in Table 2.

[0030]

[Table 1]

[0031]

[Table 2]

The above examples were carried out with various corrosion inhibiting salts,
Table 3 shows the results of evaluation based on the chromium elution concentration. In addition, Table 3 shows an evaluation example in which a protective film is not formed as a comparative example.

[0033]

[Table 3]

As described above, according to the embodiment of the present invention, the corrosion-inhibiting salt liquid is hydrothermally oxidized in the reaction vessel 21 to provide the corrosion-inhibiting salt protective film on the inner surface of the reaction vessel 21. Therefore, when the waste liquid is subjected to the hydrothermal oxidation reaction, it is possible to prevent or reduce the corrosion of the reaction vessel 21 due to the acid or alkali generated by the hydrothermal oxidation reaction of the waste liquid. Then, by subjecting the waste liquid to a hydrothermal oxidation reaction, a protective film of a corrosion inhibiting salt can be provided on the inner surface of the reaction vessel 21, so that a uniform protective film can be formed by a simple method.

Further, the corrosion state is monitored by analyzing the treatment liquid. Since the state of salt adhesion can be monitored based on the presence or absence of corrosion, the state of the protective film can be constantly grasped, and the recoating time of the protective film can be accurately determined. In this way, when analyzing the treatment liquid,
It is not contained in the waste liquid, and it is the reaction vessel 21 or this reaction vessel 2
It is desirable to analyze the elements contained in the parts in 1 as targets. If the effect duration of the protective film is known in advance by the concentration of the corrosion-inhibiting salt solution and the hydrothermal reaction treatment time of the corrosion-inhibiting salt solution, the effect duration of the protective film is also determined by analysis of the treatment liquid at that time. If is known,
The protective film may be recoated before the effect duration time has elapsed.

In the above-described embodiment, the example in which the corrosion-inhibiting salt liquid is hydrothermally oxidized in the reaction vessel 21 to provide the corrosion-inhibiting salt protective film on the inner surface of the reaction vessel 21 has been described. Before assembling, a protective film may be provided by thermal spraying or concentration, and then assembled. In this case, it is desirable to form the protective film on all the surfaces, but the protective film may be formed only on the highly corroded portion or the parts.

Although a corrosion inhibiting salt has been shown as a material for forming the protective film, sodium salts of organic acids and alkaline earth metal salts may be used in addition to the corrosion inhibiting salt.
The organic acid sodium salt and alkaline earth metal salt are oxidized in the organic acid portion in a hydrothermal oxidizing environment to form sodium carbonate, an alkaline earth metal oxide, and an alkaline earth metal carbonate, which are precipitated. Accumulate. When a sodium salt of an organic acid or an alkaline earth metal salt is used, the organic acid salt dissolves in water, so that it can be easily supplied by the high-pressure liquid feed pump 19, and each salt is converted by the hydrothermal oxidation reaction. Since it is generated, the particle size of each salt is small, and a dense protective film can be coated.

[0038]

As described above, according to the present invention, since the protective film such as the corrosion-inhibiting salt is provided on at least a part of the inner surface of the reaction vessel, the object to be treated is subjected to the hydrothermal oxidation reaction. It is possible to prevent or reduce the corrosion of the reaction vessel due to the salt produced by the hydrothermal oxidation reaction of the substance. Then, before starting the hydrothermal oxidation reaction of the object to be treated, at least a part of the reaction vessel or parts in the reaction vessel is treated with an alkali metal or alkaline earth metal oxide, sulfate, carbonate or carbon hydrogen. By coating with at least one selected from salts, or before starting the hydrothermal oxidation reaction of the object to be treated, at least a part of the reaction vessel or parts in the reaction vessel is treated with an alkali metal or an organic acid. Since a protective film can be provided by supplying a solution containing an alkaline earth metal salt under hydrothermal reaction conditions and coating with the salt produced, a uniform protective film can be formed by a simple method. it can. Furthermore, by analyzing the processing liquid, the state of salt adhesion can be monitored, so the state of the protective film can be constantly grasped,
It is possible to accurately determine the recoating time of the protective film.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a hydrothermal oxidation treatment apparatus which is an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a schematic configuration of the reaction container shown in FIG.

[Explanation of symbols]

1 Processing object storage tank 2,6,9,11,14,17 Supply pipe 3,18 Open / close valve 4,10,12,19 High-pressure liquid delivery pump 5 Auxiliary fuel storage tank 7 High pressure pump 8 aquarium 13 Air compressor 15 Preheater 16 storage tanks 21 Reaction vessel 22 Cylindrical part 22a Quench water supply hole 23 Liner 24 bases 24a outlet (hole) 24b opening 25 nozzles 31 scraper 32 rotation axis 32a fin 33 Scraper body 41 Drive mechanism 42 chains 51 discharge pipe 52 Cooler 53 Gas-liquid separator 54 Gas exhaust pipe 55,57 Pressure reducing valve 56 Liquid discharge pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B01J 19/00 B01J 19/00 H J (72) Inventor Masato Miyake 1200 Manda, Hiratsuka-shi, Kanagawa Made by Komatsu Ltd. F-Term in the Central Research Laboratory (reference) 4G075 AA01 AA37 AA42 AA53 AA65 BA05 CA65 CA66 DA02 EB12 FB20 FC09

Claims (6)

[Claims] 1. A hydrothermal reaction treatment method in which a material to be processed is treated by a hydrothermal oxidation reaction in a reaction vessel in which water is in a supercritical state or a subcritical state, and the treatment is started. Before that, at least a part of the reaction vessel or parts in the reaction vessel is coated with at least one selected from oxides, sulfates, carbonates or hydrogencarbonates of alkali metals or alkaline earth metals. A feature of the hydrothermal reaction treatment method. 2. A hydrothermal reaction treatment method in which a material to be treated is subjected to a hydrothermal oxidation reaction in a reaction container in which water is in a supercritical state or a subcritical state, and the treatment is started. Before, at least a part of the reaction vessel and parts in the reaction vessel is supplied with a liquid containing an alkali metal or alkaline earth metal salt of an organic acid under hydrothermal oxidation reaction conditions, and coated with a salt produced, A hydrothermal reaction treatment method characterized by the above. 3. The hydrothermal reaction treatment method according to claim 1, wherein the treatment liquid for the hydrothermal oxidation reaction is analyzed to monitor the corrosion state. . 4. A hydrothermal reaction treatment apparatus which treats an object to be hydrothermally oxidized in a reaction vessel in which water is in a supercritical state or a subcritical state, to treat the reaction vessel or parts in the reaction vessel in advance. At least a part of the above is coated with at least one selected from an oxide of an alkali metal or an alkaline earth metal, a sulfate, a carbonate or a hydrogencarbonate, and a hydrothermal reaction treatment apparatus characterized by the above-mentioned. 5. A hydrothermal reaction treatment apparatus which treats an object to be hydrothermally oxidized in a reaction vessel in which water is in a supercritical state or a subcritical state, to treat the reaction vessel and parts in the reaction vessel in advance. At least a part of the above is supplied with a liquid containing an alkali metal salt or an alkaline earth metal salt of an organic acid under hydrothermal oxidation reaction conditions, and coated with a salt to be produced. 6. The hydrothermal reaction treatment apparatus according to claim 4 or 5, further comprising means for analyzing a treatment liquid of the hydrothermal oxidation reaction and monitoring a corrosion state. Thermal reaction processor.