JP2002177975A - Supercritical hydroxylation decomposition equipment for organic matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide supercritical hydroxylation decomposition equipment which is capable of stably oxidizing factory waste liquids, etc., even if the concentration and characteristic of the organic matter included in the factory waste liquid, etc., fluctuate. SOLUTION: The equipment for supercritical hydroxylation decomposition of organic matter by reacting the organic matter and an oxidizing agent in supercritical water is provided with means 1 and 2 for supplying the material to be treated which supply the fluid mixed with the material to be treated of the organic matter, water and the oxidizing agent under pressurization above the supercritical pressure of the water, a reactor 4 which effects the supercritical hydroxylation reaction of the fluid mixed with the material to be treated, a cooling means 9 which cools the treated fluid after the reaction flowing out of the reactor 4 and take-out means 10 and 11 which take out the cooled treated fluid flowing out of the cooling means 9. The supercritical hydroxylation decomposition equipment for the organic matter is provided with a heat exchange means 3 which effects a heat exchange between the fluid mixed with the material to be treated and the treated fluid after the reaction in the fore stage of the reactor 4, is provided with a bypass flow passage 5 in which the treated fluid flowing out of the reactor bypasses and is provided with a cooler 6 for bypassing in this bypass flow passage and a flow rate control valve 7 in the post stage thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a supercritical water oxidation apparatus and a supercritical water oxidation method for oxidizing industrial wastewater or sewage sludge containing organic matter using supercritical water.

[0002]

2. Description of the Related Art Conventionally, incineration has been used as a method for treating industrial wastewater containing organic substances. However,
Large amounts of supplementary fuel were required when the organic matter concentration was low.

On the other hand, in recent years, a method of directly oxidizing a factory waste liquid or the like using water in a supercritical state has been proposed.

[0004] However, even in the method of supercritical water oxidation of a factory effluent or the like, when the concentration of the organic substance in the effluent is low, it is difficult to reach the target reaction temperature only by the calorific value of the organic substance. there were. Therefore, in order to supercritically oxidize a dilute aqueous solution containing an organic substance such as a factory waste liquid, it is necessary to preheat an object to be treated before sending it to a reactor. As a method of preheating, there is a method of preheating a fluid to be treated by a heater such as a heater. However, a heat exchanger is used to treat a fluid to be treated (low-temperature fluid) before the reaction and a fluid to be treated (high-temperature fluid) after the reaction. The method of performing heat exchange is efficient.

When performing heat exchange, the temperature of the object after heat exchange is determined by the capacity of the heat exchanger and the temperature and flow rate of the object and the processing fluid at the inlet of the heat exchanger. However, if the temperature of the object to be processed after the heat exchange becomes low, the ultimate temperature (reaction temperature) after the reaction becomes lower than the target temperature, and satisfactory oxidation treatment cannot be performed. Conversely, if the temperature of the object to be processed after the heat exchange becomes high, the reaction temperature becomes high, which causes a problem on the apparatus.

Further, when the concentration of the organic substance and the calorific value of the object to be processed fluctuate, even if the temperature of the object to be processed after the heat exchange is the same, the temperature of the object to be processed fluctuates from the previous reaction temperature, and the same problem occurs.

[0007] Therefore, when supercritical water oxidation is performed after preheating, it is necessary to control the reaction temperature by preheating the object to be treated or by adjusting the calorific value of the object to be treated.

As a method of controlling the temperature, when the calorific value is insufficient, an auxiliary fuel is supplied to increase the calorific value, or the temperature after preheating by heating with a heater provided between the heat exchanger and the reactor. , The reaction temperature can be controlled to be constant. When the heat amount is excessive, there is a method of providing a bypass line to reduce the amount of processing fluid flowing into the heat exchanger and controlling the reaction temperature. Japanese Patent Application Laid-Open No. H11-138198 discloses a technique for adjusting the flow rate of a processing fluid by providing a bypass line in the flow path of the processing fluid after the reaction. FIG. 5 shows an outline of the flow.

In FIG. 5, objects to be treated such as factory waste liquid are:
The pressure of water is increased to a value equal to or higher than the critical pressure of water by a treatment object supply pump (not shown), oxygen is supplied by an oxygen supply pump (not shown), and the treatment object and oxygen are mixed to form a preheater (heat exchanger) It flows into 51. The object to be processed is heated by performing heat exchange with the processing fluid flowing out of the reactor 53 in the heat exchanger 51, and then flows into the reactor 53. In the reactor 53, the supercritical hydroxylation reaction proceeds, and the material to be treated is oxidatively decomposed and flows out of the reactor 53 as a processing fluid composed of water, carbon dioxide, nitrogen and inorganic substances. The processing fluid flows into the heat exchanger 51 and is cooled by performing heat exchange with the object to be processed. Thereafter, the processing fluid is further cooled by the cooler 55 and is cooled by the gas-liquid separator 5.
Flow into 6. The gas-liquid separator 56 separates the gaseous phase and the liquid phase, and discharges them to the outside via the pressure regulating valves 57 and 58.

In the technique disclosed in Japanese Patent Application Laid-Open No. H11-138198 shown in FIG. 5, in order to reliably oxidize an organic substance even when the concentration of the organic substance and the properties of the organic substance fluctuate, the heat exchanger 51 is provided downstream. It is characterized in that an electric heater 52 is provided, a flow path for bypassing the processing fluid is provided, and a flow control valve 54 for adjusting the flow rate of the processing fluid to be bypassed is provided. That is, when the organic matter concentration of the processing object is high or the reaction heat is large, the opening degree of the flow control valve 54 is increased so that the heat recovery amount in the heat exchanger 51 is reduced. Control is performed to reduce the flow rate of the inflowing high-temperature processing fluid. When the concentration of the organic substance in the object to be processed is low or the reaction heat is low, the temperature of the object to be processed flowing into the reactor 53 is increased by the electric heater 52.

Further, a method has been proposed in which a processing fluid is cooled by passing through a cooler and then introduced into a heat exchanger for preheating (Japanese Patent Laid-Open No. Hei 10-328699).

[0012]

Problems to be Solved by the Invention
When a bypass line is provided as disclosed in Japanese Patent Publication No. 98, it is necessary to adjust the flow rate of the processing fluid to be bypassed, but the processing fluid flowing out of the reactor is at a high temperature and a high pressure. There are virtually no flow control valves that can be used.

As disclosed in Japanese Patent Application Laid-Open No. 10-328699, when the temperature of a processing fluid is controlled by passing it through a cooler, cooling water is not supplied when cooling is not required, but the processing fluid flows through the cooler. Therefore, the temperature of the cooling water may rise to near the reaction temperature. Therefore, it is necessary to provide the cooling water with a heat-resistant specification, and an increase in cost is inevitable.

The problem to be solved by the present invention is to solve the above-mentioned drawbacks of the prior art, and to stably oxidize factory waste liquid and the like even if the concentration of organic substances contained in the factory waste liquid and the properties of the organic substances fluctuate. An object of the present invention is to provide a critical hydroxylation decomposition apparatus.

[0015]

According to a first aspect of the present invention, there is provided an apparatus for reacting an organic substance and an oxidizing agent in supercritical water to supercritically hydrolyze the organic substance. A treatment object supply means for supplying a treatment target mixed fluid of the organic substance, water and the oxidizing agent to a pressure higher than a critical pressure of water, a reactor for performing a supercritical water oxidation reaction of the treatment target mixed fluid, A supercritical hydroxylation decomposition apparatus comprising: a cooling means for cooling a processing fluid after a reaction flowing out of a reactor; and a take-out means for taking out a cooled processing fluid flowing out from the cooling means. A heat exchange means for performing heat exchange between the product mixed fluid and the processed processing fluid after the reaction is provided at a stage preceding the reactor, and a bypass flow path through which the processing fluid flowing out of the reactor is bypassed is provided. Cooler for bypass and then It relates supercritical water oxidation decomposition apparatus of the organic matter which is characterized in that a flow regulating valve.

According to a second aspect of the present invention, there is provided the supercritical hydroxylation decomposition apparatus, wherein the flow path of the processing fluid flowing out of the flow control valve provided in the bypass flow path is formed by the heat flow. The processing fluid is connected to a flow path of the processing fluid flowing out of the exchange means, and the combined processing fluid is guided to the cooler.

According to a third aspect of the present invention, there is provided the supercritical hydroxylation decomposition apparatus, wherein the flow path of the processing fluid flowing out of the flow control valve provided in the bypass flow path is formed by the heat flow. The heat exchanger is connected to an inlet on the heat supply side of the exchange means, and guides the processing fluid flowing out of the heat exchange means to the cooler.

According to a third aspect of the present invention, there is provided the supercritical hydroxylation decomposition apparatus, wherein the flow path of the processing fluid flowing out of the flow control valve provided in the bypass flow path is formed by the heat flow. The heat exchanger is connected to an inlet on the heat supply side of the exchange means, and guides the processing fluid flowing out of the heat exchange means to the cooler.

According to a fourth aspect of the present invention, there is provided an apparatus for reacting an organic substance with an oxidizing agent in supercritical water to supercritically decompose the organic substance, wherein the organic substance, water and oxidizing agent are dissolved. An object supply means for supplying the object mixture fluid at a pressure equal to or higher than the critical pressure of water, a reactor for performing a supercritical hydroxylation reaction of the object mixture fluid, and after the reaction flowing out of the reactor Cooling means for cooling the processing fluid of
Supercritical water oxidation treatment comprising pressure adjusting means for reducing the pressure of the cooled processing fluid flowing out of the cooling means, and gas-liquid separating means for gas-liquid separating the reduced pressure processing fluid flowing out of the pressure adjusting means. An apparatus, wherein a heat exchange means for performing heat exchange between a mixed fluid to be treated before a reaction and a processing fluid after a reaction is provided in a preceding stage of a reactor, and cooling for supplying cooling water at a critical pressure of water or more. A water supply means, a flow path for introducing a part of the cooling water flowing out of the cooling water supply means to a heat supply side of the heat exchanger via a flow control valve, and a remainder of the cooling water flowing out of the cooling water supply means And a supercritical water oxidation decomposition apparatus for organic matter, characterized in that a flow path for introducing the organic matter into a stage preceding the pressure control means is provided.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The supercritical hydroxylation decomposition apparatus according to the present invention is provided with a reactor for oxidatively decomposing organic 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 for bringing water to a supercritical state,
For example, the temperature is 374 ° C. or more, preferably 500 to 650.
° C, and pressure 22MPa or more, preferably 22-25M
The condition of Pa may be used. 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 supercritical hydroxylation decomposition is a pipe (tubular)
Type or Bessel type.

Since water becomes a good solvent in the supercritical state, supercritical water, organic substances and oxidizing agent form a homogeneous phase in the reactor, and the supercritical water oxidation reaction proceeds, and the reaction time is extremely short. It will be oxidatively decomposed.

The substance to be treated in the present invention is a substance having a relatively large amount of water containing organic substances such as factory waste liquid, pulp slurry, sewage sludge and the like. Can be controlled.

(First Embodiment) FIG. 1 shows a flow chart of a first embodiment of the present invention.

An article to be treated containing water and organic matter, such as a waste liquid of a factory, is pressurized by a substance supply pump 1 to a pressure higher than the critical pressure of water. The oxidant is pressurized by the oxidant supply pump 2 to a pressure higher than the critical pressure of water. The treatment object and the oxidizing agent are mixed to form a treatment object mixed fluid.

The fluid mixture to be treated flows into the heat exchanger 3 provided at the front stage of the reactor 4, where heat is exchanged between the treated fluids after the supercritical water oxidation reaction and preheated.

In order to supercritically oxidize an object having a large amount of water or an organic substance having a small heat generating capacity, a known auxiliary fuel is added to the object to be treated, or a preheater such as an electric heater is provided at the inlet of the reactor 4. A vessel may be provided for processing.

In the reactor 4, a supercritical water oxidation reaction proceeds in the mixed fluid of the processing object exceeding the critical pressure and critical temperature of water. The organic matter in the mixed fluid to be treated is oxidatively decomposed by the supercritical water oxidation reaction, and is converted into a high-temperature and high-pressure treatment fluid composed of water, carbon dioxide, nitrogen, inorganic substances, and the like.
Spill out of.

A part of the high-temperature, high-pressure processing fluid flowing out of the reactor 4 flows into the heat exchanger 3 through the flow path 5 and exchanges heat with the mixed fluid before the reaction. Is cooled and flows out of the heat exchanger 3. The other part of the processing fluid after the reaction is bypassed by the bypass channel 6 and flows into the bypass cooler 7. The high-temperature processing fluid that has flowed into the bypass cooler 7 is cooled by the cooling water and flows out of the bypass cooler 7. The flow rate of the processing fluid flowing out of the bypass cooler 7 is controlled by the flow rate control valve 8.
Since a sufficiently cooled processing fluid flows through the flow control valve 8, a normal flow control valve can be used. Also,
Since the processing fluid passing through the bypass line does not need to perform heat recovery, there is no need to control the temperature. Therefore, the flow rate of the cooling water of the bypass cooler 7 does not need to be controlled, and the cooling water only needs to flow constantly, and the temperature of the cooler does not abnormally rise.

By adjusting the opening of the flow control valve 8, the flow rate of the high-temperature processing fluid flowing into the heat exchanger 3 via the flow path 5 is controlled and given to the mixed fluid before the reaction. Since the amount of heat can be changed, the reaction temperature can be easily controlled.

The processing fluids flowing out of the heat exchanger 3 and the flow control valve 8 join and flow into the cooler 10 via the flow path 9. The processing fluid cooled by the cooler 10 may be taken out as a gas phase and a liquid phase by a take-out means. As the take-out means, for example, a combination of a pressure control valve and a gas-liquid separator can be mentioned. As shown in FIG. 1, the processing fluid flowing out of the cooler 10 is released to the atmospheric pressure by a pressure control valve 11, and then separated into a gas phase and a liquid phase by a gas-liquid separator 12, and the gas phase is exhausted. The liquid phase flows out as treated water.

In the flow chart of FIG. 1, the heat exchange means
Although the heat exchanger is exemplified, the type of the heat exchanger is not limited,
For example, the type shown in FIG. 2 can be used.

FIG. 2 is a partially enlarged view centering on the reactor of FIG. The reactor 4 shown in FIG. 2 is tubular, and the heat exchange means is a double tube heat exchanger 3 ′ provided near the inlet of the reactor 4.

(Second Embodiment) In the first embodiment, an example has been shown in which the bypassed processing fluid is merged with the processing fluid flowing out of the heat exchange means. However, the bypass processing fluid is supplied with heat from the heat exchange means. It may be made to flow into the side.

FIG. 3 is a flowchart showing the second embodiment. The same components as those shown in the first embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

The second embodiment is different from the first embodiment only in the connection destination of the bypassed processing fluid flow path. As shown in FIG. 3, the bypassed processing fluid is used for bypass. After being cooled by the cooler 7 and having its flow rate adjusted by the flow rate adjusting valve 8, it is connected to the heat supply side of the heat exchanger 3. The processing fluids that have flowed out of the reactor 3 and have merged and flow into the heat supply side of the heat exchange means, perform heat exchange with the mixed fluid of the workpiece before the reaction, and flow out of the heat exchange means. ,
Further cooling is performed by the cooler 10 through the flow path 9.

In the second embodiment, since the temperature of the processing fluid flowing into the heat exchanger 3 decreases, the temperature of the heat exchanger outlet of the fluid to be processed can be rapidly reduced.

(Third Embodiment) The reaction temperature may be kept constant by combining high-pressure cooling water with the processing fluid and supplying it to the heat exchange means without bypassing the processing fluid after the reaction.

FIG. 4 is a flowchart showing the third embodiment. The same components as those shown in the first embodiment of FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 4, the processing fluid flowing out of the reactor 4 is guided to the heat supply side of the heat exchanger 3 without branching. In order to control the reaction temperature, the cooling water is supplied by a high-pressure metering pump 13 to a pressure higher than the critical pressure of water. Part of the cooling water supplied from the high-pressure metering pump 13 is combined with the processing fluid flowing out of the reactor 4 via the flow control valve 8 and supplied to the heat supply side of the heat exchanger 3. The processing fluid and the cooling water exchange heat with the mixed fluid before the reaction in the heat exchanger 3 and flow out to the cooler 10 through the flow path 9. The remainder of the cooling water supplied from the high-pressure metering pump 13 is joined at the outlet of the cooler 10.

According to the apparatus shown in FIG. 4, since the temperature of the processing fluid flowing into the heat exchanger 3 can be reduced, the amount of heat exchanged can be reduced, and the opening of the flow control valve 8 is adjusted. Thus, the reaction temperature can be controlled.

Since the flow rate of the cooling water that joins before the heat exchanger 3 fluctuates, the flow rate flowing through the pressure control valve 11 for adjusting the pressure in the system fluctuates as it is. Since the characteristics of the pressure control valve are basically determined by the rated flow rate and the pressure, it is difficult to control the pressure if there is a sudden change in the flow rate.

However, in the present embodiment, a fixed amount of cooling water is supplied by the high-pressure metering pump 13, and the water unnecessary for cooling is joined before the pressure control valve 11, so that the flow rate through the pressure control valve 11 is reduced. Is constant, and pressure control can be easily performed.

[0043]

According to the present invention, the reaction temperature can be easily controlled by controlling the opening of the flow control valve provided in the bypass line. In addition, since the flow rate is adjusted after cooling the bypassed processing fluid, a normal flow rate control valve can be used, and the cooler does not have to be heat-resistant.

According to the present invention, the reaction temperature can be easily controlled. Further, since the amount of fluid flowing out of the reaction system is constant, control of the pressure control valve is facilitated.

[Brief description of the drawings]

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

FIG. 2 is a partial flow chart showing another example of the first embodiment of the present invention.

FIG. 3 is a flowchart showing an example of a second embodiment of the present invention.

FIG. 4 is a flowchart showing an example of a third embodiment of the present invention.

FIG. 5 is a flowchart showing a conventional supercritical hydroxylation decomposition apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing object supply pump 2 Oxidant supply pump 3 Heat exchanger 4 Reactor 5 Flow path 6 Bypass flow path 7 Bypass cooler 8 Flow control valve 9 Flow path 10 Cooler 11 Pressure control valve 12 Gas-liquid separator 13 High pressure metering pump

Claims (4)

[Claims] In an apparatus for reacting an organic substance with an oxidizing agent in supercritical water to supercritically decompose the organic substance, a mixed fluid of the organic substance, water and the oxidizing agent is applied to a pressure higher than the critical pressure of water. Pressure-supplied processing object supply means, a reactor for performing a supercritical hydroxylation reaction of the processing object mixed fluid, and a cooling means for cooling the reaction processing fluid flowing out of the reactor,
A supercritical hydroxylation decomposition apparatus comprising a take-out means for taking out a cooled processing fluid flowing out of the cooling means,
Heat exchange means for performing heat exchange between the mixture fluid to be processed before the reaction and the processing fluid after the reaction is provided at the previous stage of the reactor, and further provided with a bypass flow path through which the processing fluid flowing out of the reactor bypasses, An organic supercritical water splitting / decomposing apparatus comprising a bypass cooler provided in the bypass flow path and a flow rate control valve provided at a subsequent stage thereof. 2. In the supercritical hydroxylation decomposition apparatus, a flow path of a processing fluid flowing out of a flow control valve provided in a bypass flow path is connected to a flow path of a processing fluid flowing out of the heat exchange means. 2. The apparatus for supercritically decomposing organic matter according to claim 1, wherein the treated fluid is guided to the cooler. 3. In the supercritical hydroxylation / decomposition apparatus, a flow path of a processing fluid flowing out of a flow control valve provided in a bypass flow path is connected to an inlet on a heat supply side of the heat exchange means. The apparatus for supercritically decomposing organic matter according to claim 1, wherein the processing fluid flowing out of the means is guided to the cooler. 4. An apparatus for reacting an organic substance with an oxidizing agent in supercritical water and supercritically decomposing the organic substance by applying a mixed fluid of the organic substance, water and the oxidizing agent to a pressure higher than the critical pressure of water. Pressure-supplied processing object supply means, a reactor for performing a supercritical hydroxylation reaction of the processing object mixed fluid, and a cooling means for cooling the reaction processing fluid flowing out of the reactor,
Supercritical water oxidation treatment comprising pressure adjusting means for reducing the pressure of the cooled processing fluid flowing out of the cooling means, and gas-liquid separating means for gas-liquid separating the reduced pressure processing fluid flowing out of the pressure adjusting means. An apparatus, wherein a heat exchange means for performing heat exchange between a mixed fluid to be treated before a reaction and a processing fluid after a reaction is provided in a preceding stage of a reactor, and cooling for supplying cooling water at a critical pressure of water or more. A water supply means, a flow path for introducing a part of the cooling water flowing out of the cooling water supply means to a heat supply side of the heat exchanger via a flow control valve, and a remainder of the cooling water flowing out of the cooling water supply means A supercritical water oxidation decomposition apparatus for organic matter, comprising: a flow path for introducing a gas to a stage preceding the pressure control means.