JP2003326149A - Hydrothermal reaction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrothermal reaction method for efficiently treating a paraffinic compound which is in solid state at a normal temperature, at a low cost while preventing liquid transportation failure and inferior mixing with an oxidizing agent. <P>SOLUTION: A paraffinic compound and a petroleum-base solvent are introduced into a dissolution tank 1 and heated to dissolve the paraffinic compound in the petroleum-base solvent and obtain a solution 12. The solution 12 is sent to a supply apparatus 2a of a hydrothermal reactor 2 at a normal temperature through a line 13 by a high pressure pump P1. A waste liquid or water is sent to the supply apparatus 2a by a high pressure pump P2, and an oxidizing agent is sent to the supply apparatus 2a by an oxidizing agent supply means 15. In the supply apparatus 2a, a mixed solution of the solution 12 with the waste liquid or water and the oxidizing agent are mixed and supplied downward to the hydrothermal reactor 2 and subjected to hydrothermal reaction while being kept in supercritical or subcritical state. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hydrothermal reaction method in which a hydrothermal reaction is carried out under a supercritical or subcritical state of water, and particularly a hydrothermal reaction method suitable for decomposing waste of paraffinic compounds. It is about.

[0002]

2. Description of the Related Art A hydrothermal reaction process in which a hydrothermal reaction is carried out under a supercritical or subcritical state of water is drawing attention as a technique capable of oxidatively decomposing organic matter in a waste liquid to a high level in a short time. By performing the hydrothermal reaction, the organic component in the object to be treated is decomposed into carbon dioxide, and the nitrogen component is decomposed into nitrogen gas (ammonia and nitrate nitrogen are also generated depending on the conditions). Heteroatoms such as phosphorus and sulfur are also oxidized to phosphate ions and sulfate ions, respectively.

When the waste is treated by utilizing the hydrothermal reaction as described above, it is usually carried out by continuously supplying a liquid object to the hydrothermal reactor by means of a pump or the like. When treating a paraffinic compound in such a hydrothermal reaction treatment, since the paraffinic compound is a solid at room temperature, it is difficult to continuously supply it to the hydrothermal reactor, and therefore the treatment cannot be performed efficiently. .

Since the paraffinic compound is fluidized by heating, it is possible to continuously supply it to the hydrothermal reactor in a heated state. In this case, in order to maintain the fluidized state of the paraffinic compound, water is used. It is necessary to heat the system passage until it is introduced into the thermal reactor, and it is necessary to use a pump that can handle high temperatures. This increases the size of the apparatus and increases the cost. In addition, when the solidified paraffinic compound is contained in the fluidized product due to insufficient dissolution or fluidization, poor liquid transfer due to adhesion inside the pipe, poor mixing with the oxidizer in the reactor, and deterioration of processing performance There is.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to efficiently treat paraffinic compounds, which are solid at room temperature, at low cost by preventing liquid transfer defects and mixing defects with oxidizing agents. It is to propose a hydrothermal reaction method.

[0006]

The present invention is the following hydrothermal reaction method. (1) A dissolving step of dissolving a paraffinic compound in a petroleum solvent, a supplying step of supplying the dissolving solution obtained in the dissolving step to a hydrothermal reactor, and a dissolving solution supplied to the hydrothermal reactor with water and And a hydrothermal reaction step in which hydrothermal reaction is carried out in a supercritical or subcritical state of water in the presence of an oxidizing agent. (2) The hydrothermal reaction method according to (1) above, wherein the paraffinic compound is dissolved in a petroleum solvent by heating. (3) The hydrothermal reaction method according to (1) or (2) above, wherein a waste liquid is supplied to the hydrothermal reactor as water necessary for the hydrothermal reaction step.

The paraffinic compound to be treated in the present invention is a paraffinic compound which is solid or has low fluidity at room temperature, and is a natural paraffin wax, carnauba wax, wood wax, beeswax, montan wax, polyethylene wax, etc. Or synthetic wax; Vaseline and the like can be mentioned. The paraffinic compound may be a single type or a mixture of two or more types. Further, the paraffinic compound may contain an organic substance other than the paraffinic compound. Specific examples of the paraffinic compound to be treated include paraffinic compounds discharged from chemical factories, pharmaceutical factories and the like. When treating the paraffinic compound contained in the waste liquid or the wastewater, the waste liquid or the wastewater can be subjected to solid-liquid separation, and the solid content can be used as the paraffinic compound for the treatment. Further, the separated liquid can be supplied to a hydrothermal reactor (hereinafter sometimes simply referred to as a reactor) as water necessary for the hydrothermal reaction.

In the dissolving step in the present invention, the paraffinic compound is dissolved in a petroleum solvent to obtain a paraffinic compound solution. As the petroleum solvent, any solvent capable of dissolving a paraffinic compound can be used without limitation, and examples thereof include kerosene, m kerosene, petroleum naphtha, aromatic naphtha, benzene, toluene, xylene, cyclohexane, and a mixture thereof. Petroleum solvents do not need to be of high purity used as reagents or industrial supplies,
A petroleum solvent to be treated as a waste, a waste containing a petroleum solvent, a liquid containing a petroleum solvent, or the like can be used. The amount of the petroleum-based solvent used is arbitrarily determined within a range in which the paraffinic compound can be fluidized. However, when the viscosity increases, it becomes difficult to transfer the liquid. Is preferred.

When the paraffinic compound is dissolved in the petroleum solvent, it is preferable to heat the paraffinic compound to dissolve it in the petroleum solvent. For example, a paraffin compound can be added to a petroleum solvent and heated to 30 to 80 ° C. to dissolve the paraffin compound. Alternatively, the paraffinic compound may be heated to 30 to 80 ° C. to be fluidized and then added to a petroleum solvent to dissolve the paraffinic compound.

A solution obtained by dissolving a paraffinic compound in a petroleum solvent does not precipitate even if the paraffinic compound is in a dissolved state even after returning to room temperature. Therefore, the solution can be sent at room temperature, and the paraffinic compound is prevented from adhering to the solution sending path. Furthermore, the solution can be easily and uniformly mixed with water, an oxidizing agent, etc., and the hydrothermal reaction can be efficiently advanced to increase the decomposition rate.

In the supplying step, the solution obtained in the dissolving step is supplied to the hydrothermal reactor. Since the petroleum solvent in which the paraffinic compound is dissolved is also used as the auxiliary fuel in the hydrothermal reaction, the solution can be supplied to the hydrothermal reactor as a substitute for the auxiliary fuel or a part of the auxiliary fuel.
Since the dissolved solution can be continuously sent to the hydrothermal reactor at room temperature, it is not necessary to heat the pipes, and it is not necessary to use a pump for sending liquid or a pump compatible with high temperature. It is possible to prevent liquid defects and easily process at low cost.

In the hydrothermal reaction step, the solution is hydrothermally reacted in the presence of water and an oxidizing agent in a supercritical or subcritical state of water. As water required for the hydrothermal reaction, industrial water can be supplied to the reactor and used, but it is preferable to use waste liquid. When the waste liquid is used, organic substances in the waste liquid are decomposed, so that the waste liquid can be treated at the same time. As the waste liquid, waste liquid or waste water generated from a factory or the like can be used, or a separation liquid obtained by separating a paraffinic compound can be used.

In the hydrothermal reaction, the substances to be treated such as the above-mentioned solution and waste liquid are introduced into a hydrothermal reactor, and paraffin compounds,
Oxidative decomposition of organic substances such as petroleum solvents and organic substances in waste liquid. The hydrothermal reactor is configured to oxidatively decompose organic matter by a hydrothermal reaction in the presence of an oxidant in a supercritical or subcritical state of water.

Here, the hydrothermal reaction is a reaction of oxidatively decomposing an organic substance by an oxidative reaction in the presence of water at high temperature and high pressure in a supercritical or subcritical state and an oxidizing agent. The supercritical state is a state of 374 ° C. or higher and 22 MPa or higher. The subcritical state is, for example, 374 ° C. or higher and 2.5 MPa or higher 22
A state of less than MPa, less than 374 ° C., 22 MPa or more, or a temperature of 374 ° C. or less, less than 22 MPa is a high temperature / high pressure state close to the critical point.

Such a hydrothermal reaction is carried out in a hydrothermal reactor in a state where an organic substance is mixed with an oxidizing agent, and these mixtures undergo a hydrothermal reaction inside the reactor. As an oxidant,
Air, oxygen, liquid oxygen, hydrogen peroxide, nitric acid, nitrous acid,
Nitrate, nitrite and the like can be used.

The dissolution liquid and the waste liquid can be separately supplied from a multi-tube nozzle provided at the supply port of the hydrothermal reactor and supplied as a multi-layer flow, or the waste liquid can be supplied to the system passage for sending the dissolution liquid. It is also possible to supply the above components and mix them, and to supply them to the hydrothermal reactor in a mixed state. The oxidizing agent may be mixed with the material to be treated and supplied, or may be supplied as a multi-layer flow from a multi-tube nozzle. If necessary, a catalyst, a neutralizing agent and the like may be added, and these can be mixed with the material to be treated or separately supplied to the reactor.

The hydrothermal reactor used in the present invention is made of a heat-resistant and pressure-resistant material in a cylindrical reactor arranged substantially vertically so as to carry out the hydrothermal reaction in a supercritical or subcritical state. . If the reaction heat alone does not reach the supercritical or subcritical state, an external heating means can be provided. The reactor may have a cylindrical shape, an elliptic shape, or a polygonal shape, and the lower end portion may have a cone shape. When a hydrothermal reaction is carried out in a supercritical or subcritical state by such a hydrothermal reactor, organic substances are oxidized by an oxidant and finally decomposed into water and carbon dioxide, or hydrolyzed to lower molecular weight, and inorganic substances Separates in the solid or molten state.
The reaction product is as it is, or after solid matter is separated, cooled,
Gas, liquid and solid are separated by operations such as gas-liquid separation, decompression, solid-liquid separation and the like.

As the above-mentioned hydrothermal reactor, the one conventionally used for the hydrothermal reaction can be used as it is, but as shown in JP-A-11-156186, a mixed reaction accompanied by a reverse flow in the upper part. In the upper and lower parts of the reactor, a mixed flow of the material to be treated and the oxidant is supplied in a downward flow from a supply device installed in the upper part to a substantially vertical reactor forming a plug flow reaction region in the lower part. A structure is preferred in which a mixed flow accompanied by backflow is formed in the reaction zone for hydrothermal reaction, and a parallel downward plug flow is formed in the lower plug flow reaction zone for additional hydrothermal reaction.

The material of the hydrothermal reactor is not limited, but is preferably a corrosion resistant material such as Hastelloy, Inconel or stainless steel. The hydrothermal reactor is preferably provided with a corrosion resistant liner. The corrosion-resistant liner is not particularly limited, and a corrosion-resistant liner having a gap between the corrosion-resistant liner and the pressure load wall as disclosed in JP-A-11-156186 can be used.

The hydrothermal reactor may be provided with cooling means for cooling the reaction mixture before it is discharged from the outlet. The cooling means is not particularly limited, but water can be introduced into the reactor to cool it, and the inorganic salt can be dissolved to accelerate its discharge. Further, water containing an acid or an alkali may be introduced into the reactor and cooled to neutralize the alkali or the acid. If the solids are very sticky, a mechanical removal device can be provided to remove the solids adhering to the inner wall of the reactor. The mechanical removing device for removing solids is not particularly limited, but a substantially cylindrical scraper including a notched window portion disclosed in JP-A-11-156186 is suitable.

When a neutral salt is deposited in the hydrothermal reactor as the hydrothermal reaction progresses, it is desirable to use a salt deposition preventing means and a discharging means in the hydrothermal reactor. As a specific method, means for dissolving and discharging salt by providing a water layer in the lower part of the hydrothermal reactor (patent 2726293) and means for mechanically scraping salt (USP 5,100,560, JP-A-10-1)
5566, JP-A-11-253786), means for preventing adhesion by ejecting fluid from the reactor surface (JP-A-9-2).
Known methods such as 99966) can be adopted.

Separation means may be provided for separating solids in the reaction fluid discharged from the hydrothermal reactor. In particular,
Inorganic salts are not dissolved in the reaction fluid in the supercritical state but are contained as a solid, so that the treated water can be easily reused by separating the insolubilized inorganic substances. The solid matter separating means is not particularly limited, and a container having an inlet for introducing the reaction fluid from the hydrothermal reactor and an outlet for discharging the fluid from which the solid has been removed, and the reaction fluid disposed in the container to the reaction fluid. A means provided with a means for removing and discharging the contained solid can be used. Further, means for gas-liquid separation or solid-liquid separation can be provided in the steps of cooling and depressurizing.

The means for starting the reaction by the hydrothermal reactor is not particularly limited. Usually, the reactor is preheated to around a predetermined reaction temperature at the start of the reaction. Preheating can be performed by providing a heating device in the reactor or by introducing heated water or air provided in the object to be treated and / or the oxidant supply passage. Also, normally, supplying water and an oxidant to the reactor,
It is pressurized to a predetermined pressure by a pressure adjusting valve that is usually provided. After the temperature and pressure have been adjusted to predetermined values, a fluid containing the material to be treated is supplied to start the hydrothermal reaction. Organic substances are decomposed by the reaction, and heat of reaction is generated. When a mixing reaction zone involving backflow is provided in the upper part of the hydrothermal reactor, the temperature of the fluid rises because the organic matter, the oxidant and the contents of the reactor are sufficiently mixed by the mixing action involving backflow. As a result, the supplied organic substance promptly starts the hydrothermal reaction, and the stable reaction is continued. The reaction fluid moves downward in the reactor, continuously reacts in the plug flow reaction region, and is then discharged from the discharge port. Reactor length: diameter ratio of 1: 1
~ 100: 1 is preferred.

The reaction fluid discharged from the hydrothermal reactor is used as it is, or after solids are separated, gas-liquid separation is carried out, and the pressures of the gas phase and the liquid phase are reduced. When liquid is produced by cooling in the reactor, the liquid is separated together with the solid at the stage of leaving the reactor,
If necessary, further cooling, gas-liquid separation and solid-liquid separation can be performed. The finally produced water, gas, and solid are directly recovered as energy, reused as a substance, or directly or additionally treated and disposed of.

In the present invention, since the paraffinic compound is dissolved in the petroleum solvent and supplied to the hydrothermal reactor, it is not necessary to provide a heating device for maintaining the fluidity of the paraffinic compound in the system passage or the like. Further, it is not necessary to use a liquid transfer pump that can handle high temperatures, and it is possible to prevent liquid transfer failure and process efficiently at low cost. Further, since the solution is easily and uniformly mixed with water, an oxidizing agent, etc., it is possible to prevent improper mixing, allow the hydrothermal reaction to proceed efficiently, and increase the decomposition rate.

[0026]

According to the hydrothermal reaction method of the present invention, the paraffinic compound is dissolved in the petroleum solvent and supplied to the hydrothermal reactor. It is possible to prevent poor mixing with the oxidant and the oxidant, and to perform the treatment efficiently at low cost.

[0027]

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 system diagram of a hydrothermal reaction apparatus of an embodiment for carrying out the hydrothermal reaction method of the present invention, in which 1 is a melting tank,
2 is a hydrothermal reactor, 3 is an oxidizer tank, and 4 is a gas-liquid separator.

The hydrothermal reaction treatment by the apparatus of FIG. 1 is performed as follows. First, the paraffinic compound is introduced into the dissolution tank 1 from the system 10 and the petroleum solvent is introduced from the system 11 and mixed,
Dissolve paraffinic compound in petroleum solvent and dissolve 1
Get 2. In this case, the paraffinic compound is added to the petroleum solvent and heated to 30 to 80 ° C. to dissolve the paraffinic compound, or the paraffinic compound is heated to 30 to 80 ° C. and fluidized, and then the petroleum solvent. It is preferable that the paraffinic compound is dissolved in the solution. The solution 12 is
The paraffinic compound does not precipitate even after returning to room temperature, and remains in a dissolved state, so it is possible to transfer the solution at room temperature.
No liquid transfer failure due to adhesion inside the pipe will occur.

The dissolution liquid 12 is supplied to the system 1 by the high pressure pump P1.
3 to the supply device 2a of the hydrothermal reactor 2 at room temperature.
Further, the waste liquid or water is mixed with the dissolving liquid 12 supplied from the system path 13 through the system path 14 by the high-pressure pump P2 and sent to the supply device 2a, and the oxidizing agent (for example, air, hydrogen peroxide solution) is supplied to the oxidizing agent tank. 3 from the oxidant supply means 15 to the supply device 2a through the system passage 16. As the oxidant supply means 15, an air compressor or the like can be used when a gas is used as the oxidant, and a high-pressure pump or the like can be used when a liquid is used.

In the supply device 2a, a mixed liquid of a solution and a waste liquid or water and a mixed flow of an oxidant are supplied to the hydrothermal reactor 2 in a downward flow to perform a hydrothermal reaction. As the hydrothermal reactor 2, a mixed flow accompanied by a backflow is formed in the upper mixing reaction region to perform hydrothermal reaction, and a parallel downward plug flow is formed in the lower plug flow reaction region to add additional hydrothermal heat. A structure having a reaction is preferable. In the hydrothermal reactor 2, a preheater (not shown) provided in the system passages 13, 14 or 16 at the start of the reaction performs heating to maintain the supercritical or subcritical state for the hydrothermal reaction. After the start of the hydrothermal reaction, heating by the preheater can be omitted.

The mixed flow supplied from the supply device 2a forms a mixed reaction zone accompanied by a reverse flow in the upper part of the hydrothermal reactor 2, oxidative decomposition of organic compounds containing paraffinic compounds is carried out, and turbulent flow is eliminated in the lower part. Then, a plug flow reaction zone is formed and an additional reaction is carried out. Since petroleum-based solvents serve as auxiliary fuels, auxiliary fuels other than petroleum-based solvents are unnecessary, or the amount used is small even when used.

The reaction fluid of the hydrothermal reactor 2 is introduced into the cooler 18 from the system passage 17, cooled by the cooling water supplied from the cooling water passage 19 and introduced into the gas-liquid separator 4 for gas-liquid separation. The separated gas is sent from the system path 21 to the decompression means 22 to be decompressed, and is discharged as a processing gas from the gas discharge path 23. The separated liquid is sent from the system path 25 to the decompression means 26 to be decompressed and then discharged from the liquid discharge path 27 as treated water. As the pressure reducing means 22 and 26, a pressure reducing valve, a pressure reducing device or the like can be used. The treated water discharged from the liquid discharge path 27 has a high water quality because organic substances, ammonia, and other substances to be reacted are decomposed.
It can also be recovered and used.

In the above method, since the solid paraffinic compound is dissolved in the petroleum solvent, the high pressure pump P1
As for, it is not necessary to use a high temperature one. Further, since the paraffinic compound does not precipitate as a solid in the solution 12 even at room temperature, it is not necessary to provide a heating device for maintaining the fluidity of the paraffinic compound in the system passage 13 or the like, and the solution 12 is attached to the system passage 13. It does not cause poor delivery. Further, since the oxidizer is easily and uniformly mixed with the mixed liquid in which the waste liquid or water is mixed with the dissolving liquid, the hydrothermal reaction can be efficiently advanced to increase the decomposition rate.

In FIG. 1, the solution, the waste liquid or water, and the oxidant may be separately supplied from the supply device 2a to the hydrothermal reactor 2 as a multilayer flow. Further, a solid separator may be provided at the subsequent stage of the hydrothermal reactor 2.

[0035]

EXAMPLES Example 1 3 kg of petrolatum was added to 10 liters of kerosene and heated to about 60 ° C. to dissolve petrolatum in kerosene. Even when the solution was returned to room temperature, the petrolatum did not solidify and maintained the fluidity. This solution was supplied to the hydrothermal reaction apparatus of FIG. 1 at room temperature for decomposition treatment, and a decomposition rate of 99% or higher was confirmed.

Example 2 3 kg of vaseline alone was heated to about 60 ° C. for fluidization, and then mixed with 10 liters of m kerosene at 30 ° C. and dissolved. Vaseline does not solidify even when this solution is returned to room temperature,
It was liquid. This solution was supplied to the hydrothermal reaction apparatus of FIG. 1 at room temperature for decomposition treatment, and a decomposition rate of 99% or higher was confirmed.

Comparative Example 1 3 kg of vaseline alone was heated to about 60 ° C. and fluidized. When this fluid was supplied to the hydrothermal reactor of FIG. 1 and decomposed, the decomposition rate was 80%.

[Brief description of drawings]

FIG. 1 is a system diagram of a hydrothermal reaction device of an embodiment for carrying out the hydrothermal reaction method of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Dissolution tank 2 Hydrothermal reactor 3 Oxidizing agent tank 4 Gas-liquid separator 10, 11, 13, 14, 16, 17, 21, 25 System path 12 Dissolution solution 15 Oxidizing agent supply means 18 Cooler 19 Cooling water path 22, 26 decompression means 23 gas discharge path 27 liquid discharge path

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaaki Wakita             Kurita, 3-4-3 Nishi-Shinjuku, Shinjuku-ku, Tokyo             Industry Co., Ltd. (72) Inventor Hironori Karai             Kurita, 3-4-3 Nishi-Shinjuku, Shinjuku-ku, Tokyo             Industry Co., Ltd. F-term (reference) 4D004 AA14 AC04 CA39 CC02 CC03                       DA02 DA06 DA07                 4G035 AA19

Claims (3)

[Claims] 1. A dissolving step of dissolving a paraffinic compound in a petroleum solvent, a supplying step of supplying the dissolving solution obtained in the dissolving step to a hydrothermal reactor, and a dissolving solution supplied to the hydrothermal reactor. A hydrothermal reaction method, which comprises performing a hydrothermal reaction in the supercritical or subcritical state of water in the presence of water and an oxidizing agent. 2. The hydrothermal reaction method according to claim 1, wherein the paraffinic compound is dissolved in a petroleum solvent by heating. 3. The hydrothermal reaction method according to claim 1, wherein a waste liquid is supplied to the hydrothermal reactor as water necessary for the hydrothermal reaction step.