JP2003340262A - Method and apparatus for treating hydrothermal reaction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a batch hydrothermal reaction treatment apparatus high in treatment efficiency. <P>SOLUTION: This hydrothermal reaction treatment apparatus 10 has the first freely openable/closable container type reactor 12 in which a treatment substance is housed to be subjected to batch hydrothermal reaction treatment, the second tubular reactor 14 which continuously and completely treats an intermediate treatment fluid discharged from the first reactor 12 by the hydrothermal reaction and discharges the treated fluid, and a treated fluid discharge system 16 for discharging the treated fluid supplied from the second reactor 14. A mixed fluid of supercritical water and air is introduced into the inner cylinder 12b of the first reactor 12, ascends in the inner cylinder while being brought into contact with the solid treatment substance on a support plate 12c to be subjected to the hydrothermal reaction, and descends in an annular part 12 to be discharged as the intermediate treatment fluid. The first reactor has the first annular heating oven 24 on the periphery, and the temperature of the first reactor is 200-374°C in the first treatment step and 374-650°C in the second treatment step. The second reactor is surrounded by the second heating oven 28, and the temperature of the second reactor is 400-650°C. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrothermal reaction treatment apparatus and a hydrothermal reaction treatment method, and more particularly to an apparatus and a method for efficiently performing a hydrothermal reaction treatment on a solid object. Is.

[0002]

2. Description of the Related Art At present, attention is being paid to attempts to decompose and detoxify environmental pollutants by utilizing supercritical water reaction, which has a high ability to oxidize and decompose organic substances. That is, by a supercritical water reaction utilizing high reactivity of supercritical water, harmful and hardly decomposable organic substances, such as PCB (polychlorinated biphenyl) and dioxin, which have been difficult to decompose by conventional techniques.
Decomposes organic chlorine solvents, carbon dioxide, nitrogen, water,
It is an attempt to convert into harmless products such as inorganic salts. As one of the attempts, recently, supercritical water reaction has been performed even in the treatment of various liquid and solid wastes such as sewage sludge, municipal waste, industrial wastewater, etc., containing such harmful organic compounds. Is being used.

By the way, in order to treat a contaminated solid substance in a continuous type supercritical water reactor, it is necessary to grind the solid substance into a slurry, but it is technical to grind some solid substances. There are some difficult ones. Even if the solid matter can be crushed into a slurry, there are various problems peculiar to the slurry, such as troubles in the equipment that handles the slurry and sedimentation and separation of the slurry.

Further, in the continuous treatment by making the solid matter into a slurry, (1) equipment for finely pulverizing the solid matter and supplying it to the high-pressure reaction zone is required, resulting in high equipment cost,
(2) The treatment efficiency is low because the slurry concentration cannot be increased, and (3) preheating up to the reaction start temperature is required for the treatment in the tube reactor, and the supercritical water is low because the organic matter concentration is low. Further heating is required for the progress of the reaction, and (4) since continuous treatment is performed, there is a risk of inorganic substances in the slurry adhering to and blocking the pipes and equipment, and (5) the tube reactor is corroded. There is a problem that it is difficult to take measures.

Therefore, it is necessary to put the solid matter to be treated into the reactor as it is without making it into a slurry and to carry out the supercritical water treatment in a batch system. In addition, the batch reactor is easy to suppress the corrosion of the reactor due to the supercritical water reaction, and since the reaction vessel is opened for each batch, it is easy to discharge the inorganic salt precipitated due to neutralization. It also has the excellent advantage that

Now, the construction of a conventional batch type supercritical water reactor will be described with reference to FIG. FIG. 2 is a flow sheet showing the structure of a conventional batch type supercritical water reactor. A conventional batch type supercritical water reaction apparatus 80 is an apparatus for processing an organic solid substance to be treated by a batch type supercritical water reaction, and as shown in FIG. The reactor 81 is provided with a water feeding means 82 for feeding supercritical water, and an air compressor 83 for feeding air as an oxidant to the reactor 81.

The reactor 81 comprises a lid 81a and a reactor body 8
1b, which is an openable and closable autoclave-type reactor in which a solid substance to be treated is contained and subjected to supercritical water treatment. A plate-shaped support plate 84 for passing supercritical water
Have. The lid 81a includes a lid 81a and a reactor body 81.
Reactor body 81b by bolting flanges of b together
Are linked to.

The water supply means 82 is a water tank 8 containing water.
5, the water supply pump 86 for supplying the water stored in the water tank 85, the water supplied by the water supply pump 86, and the combined water of the circulating water sent by the booster pump 94 described later flowed out from the reactor 81. A heat exchanger 8 that heats the combined water by exchanging heat with the treatment fluid and cools the fluid.
7 and a heating furnace 88 for raising the temperature of the combined water to a predetermined temperature required for the supercritical water reaction, that is, the supercritical water temperature, and supercritical water is sent to the reactor 81 via the water supply pipe 89. The air compressor 83 is a variable flow rate compressor capable of changing the discharge flow rate by adjusting the pressure and the flow rate, and the reactor 81 via the air supply pipe 90 and the water supply pipe 89.
Introduce air as an oxidant into the.

The reaction product outflow system includes an outflow pipe 91 for outflowing the processing fluid from the reactor 81, a gas-liquid separator 92 provided downstream of the heat exchanger 87, and a pressure of the gas-liquid separator 92.
Therefore, a pressure control device 93 that indirectly controls the pressure of the reactor 81 and a booster pump 94 that circulates the water component obtained by gas-liquid separation are provided.

The gas-liquid separator 92 gas-liquid separates the processing fluid to separate it into a gas component and a water component. The gas component is released to the atmosphere through a gas release pipe 95 connected to the top of the gas-liquid separator 92, or the next treatment step, for example, CO gas is contained in the gas at a concentration higher than an allowable amount. If
It is sent to the CO converter. The pressure control device 93 that controls the pressure of the gas-liquid separator 92 uses the pressure control valve 97 based on the pressure measurement value of the pressure gauge 96 provided in the gas discharge pipe 95.
The valve opening is adjusted to control the pressure of the gas-liquid separator 92, that is, the pressure in the reactor 81 to a predetermined pressure. Further, a CO concentration meter 98 is provided in the gas discharge pipe 95 in order to measure the CO gas concentration in the gas component. The water component in the gas-liquid separator 92 is boosted by the booster pump 94 and is supplied as circulating water via the water pipe 99 to the water pipe 89.
Sent to.

When operating the batch type supercritical water reactor 80, first, the reactor 81 is opened, and the solid matter to be treated for one batch operation is placed on the support plate 84, and the reactor 81 is operated.
Close. Next, the water supply pump 86 is activated to send water from the water tank 85 to the heating furnace 88 via the water supply pipe 89 via the heat exchanger 87, heat it and supply it to the reactor 81.
The treated fluid (water at the beginning of operation) flowing out from the reactor 81 enters the gas-liquid separator 92 through the heat exchanger 87, is pressurized by the booster pump 94, and is fed by the water pipe 99.
Via the water feed pipe 89, the water from the water feed pump 86 joins, is heated by the heat exchanger 87 and the heating furnace 88, then enters the reactor 81, and gradually starts circulation. As the circulating water amount by the booster pump 94 increases, the water feeding amount by the water feeding pump 86 is decreased. Eventually,
Only the amount of water that accompanies the gas from the gas discharge pipe 95 and diffuses out of the system is replenished by the water supply pump 86.

When the temperature measured by the thermometer 100 provided in the outflow pipe 91 reaches about 370 ° C., the air compressor 8
3 is started, and air is sent into the reactor 81 together with water via the air supply pipe 90 and the water supply pipe 89. Air compressor 8
While watching the temperature of the thermometer 100, the air supply amount from 3 decreases when the temperature rises quickly, and increases when the temperature rises slowly.

When the conditions in the reactor 81 reach the predetermined conditions for the supercritical water reaction, the supercritical water reaction is started and gradually progresses. The processing fluid flowing out of the outflow pipe 91 with the progress of the supercritical water reaction comes to accompany gas components such as CO ₂ gas and CO gas, and is separated by the gas-liquid separator 92,
It is discharged through the gas discharge pipe 95. At the same time, the pressure control device 93 is operated to control the pressure in the gas-liquid separator 92, that is, the pressure in the reactor 81 to a predetermined pressure.

When the CO gas concentration measured by the CO gas concentration meter 98 shows zero or the oxygen concentration shows the same value as that in the atmosphere, the supercritical water reaction in the reactor 81 reaches the end point. You can judge. When the supercritical water reaction reaches the end point, the pressure of the whole batch type supercritical water reaction device 80 is lowered, and then the reactor 81 is opened.

[0015]

However, the batch type supercritical water reactor described above has a problem of low treatment efficiency. That is, since the supercritical water is circulated and sent to the reactor, the amount of the object to be treated that can be accommodated in the reactor is limited due to the restriction on the ratio with the supercritical water as in the past. Although it has been solved, it takes a long time to perform one batch process because the treatment is performed in one reactor until the treatment is completely rendered harmless, and the treatment efficiency of the treatment is low. In the above description, the supercritical water reaction was described as an example, but this is not a problem limited to batch type processing by supercritical water reaction, for example, batch type processing by hydrothermal reaction including supercritical water reaction in general. It is a problem that corresponds to. Hydrothermal reaction is high-temperature high-pressure water, for example, temperature 180 ℃ or more, pressure 1
It refers to a reaction using hot water of MPa or more.

Therefore, an object of the present invention is to provide a hydrothermal reaction treatment apparatus and a hydrothermal reaction treatment method having high treatment efficiency.

[0017]

In order to achieve the above object, a hydrothermal reaction treatment apparatus according to the present invention accommodates a solid substance as an object to be treated, and applies the hydrothermal reaction treatment to the object to be treated. An openable and closable container-type first reactor for letting out a processing fluid,
A tube-type second reactor connected in series to the first reactor, wherein the intermediate treatment fluid flowing out from the first reactor is further subjected to continuous hydrothermal reaction treatment to flow out as a treatment fluid. There is.

In the present invention, an object to be treated, for example, an object to be treated having a high concentration of an organic substance to be treated is treated in the first reactor,
The object to be treated, although some unreacted matter remains,
For example, a treatment fluid having a low concentration of organic substances to be treated is caused to flow out of the first reactor as an intermediate treatment fluid, and the intermediate treatment fluid is continuously treated in the second reactor, thereby efficiently treating the solid matter to be treated. Can be processed.

In a preferred embodiment of the present invention, a first heating means for heating the first reactor and a second heating means for heating the second reactor.
Heating means are provided in the first reactor and the second reactor, respectively. Thereby, the reaction conditions of the first reactor and the second reactor can be set independently, so that the hydrothermal reaction treatment in each reactor can be optimized. Further, the first reactor is provided with a supply means for supplying an alkaline aqueous solution.
As a result, the acid generated by the treatment can be neutralized to form a salt, and the corrosion of the equipment downstream of the first reactor can be prevented. Further, when potassium hydroxide aqueous solution is supplied as an alkaline solution, potassium chloride salt is generated, but potassium chloride salt is more salty than when sodium hydroxide aqueous solution is supplied to generate sodium chloride salt. It is possible to reduce the adhesiveness of the resin and prevent clogging with salt.

The hydrothermal reaction treatment method according to the present invention is a container-type first reactor in which a solid substance is contained as an object to be treated, and a hydrothermal reaction treatment is applied to the object to flow out an intermediate treatment fluid. A second reactor connected in series to the first reactor, wherein the intermediate treatment fluid flowing out from the first reactor is further continuously subjected to hydrothermal reaction treatment to flow out as a treatment fluid; A hydrothermal reaction treatment device having a treatment fluid discharge system for discharging the treatment fluid flowing out, and further having a first heating means for heating the first reactor and a second heating means for heating the second reactor. A method for hydrothermally treating an object, comprising: storing a solid material in a first reactor, subsequently supplying water to the first reactor, and then discharging the first reactor, the second reactor, and a treated fluid discharge. The filling process of filling the system with water and increasing the pressure to a predetermined pressure, and then the first reaction Vessel is heated by the first heating means, a pre-reaction step for the organic matter in the solids is hydrolyzed to low molecular weight, or together with before the reaction step prior to the pre-reaction step,
By supplying supercritical water or subcritical water and an oxidant to the second reactor, a supercritical water reaction zone maintained at a temperature equal to or higher than the temperature in the first reactor is formed in the second reactor. Following the second reactor preparation step, the pre-reaction step and the second reactor preparation step, hot water and, if necessary, an oxidant are supplied to the first reactor to accelerate the hydrolysis of organic matter in the solid matter. The intermediate treatment fluid was allowed to flow out, and subsequently the second supercritical water reaction zone was formed.
Introducing the intermediate treatment fluid into the reactor from the first reactor,
And a reaction step of subjecting the intermediate treatment fluid to a supercritical water reaction treatment in the reactor.

In the reaction step of the method of the present invention, an object to be processed having a high concentration of the object to be processed is processed in the first reactor to leave a small amount of unreacted material, but a low concentration of the object to be processed. As an intermediate treatment fluid from the first reactor,
By continuously treating the intermediate treatment fluid in the second reactor, it is possible to efficiently treat the solid matter to be treated. The hot water supplied to the first reactor in the reaction step is the hot water involved in the hydrothermal reaction, and the temperature is 180 ° C or higher and the pressure is 1MP.
Water of a or higher, or subcritical water. Further, since the second reactor preparation step is provided before the reaction step and the second reactor is maintained in the standby state for the supercritical water reaction treatment, the time required for the pre-stage from the filling step to the reaction step is shortened. Therefore, the processing efficiency can be improved.

In the filling step, the first reactor, the second reactor,
In addition, at least a part of the equipment and piping of the processing fluid discharge system may be filled with an inert gas such as nitrogen gas or air in place of water to raise the pressure to a predetermined pressure. This makes it possible to increase the pressure increased by heating to a predetermined pressure during the pre-reaction step described below. Further, when the first reactor is heated by the initial pressurization with the inert gas, it is possible to secure the space for ensuring the saturated vapor pressure.

In the pre-reaction step, the temperature in the first reactor is set to 2
Maintain above 00 ° C and below 374 ° C. In addition, at the final stage of the reaction process, the temperature in the first reactor is kept at 374 for a predetermined time.
It has a reaction completion step of maintaining the temperature above 650 ° C. and below 650 ° C. and supplying supercritical water to the first reactor. In the pre-reaction step in which the concentration of the substance to be treated is high, the hydrothermal reaction treatment is performed at a relatively low reaction temperature. In the low-temperature pre-reaction step, although the reduction of molecular weight due to hydrolysis occurs, it is not perfect, and traces of organic residues remain, so in the reaction completion step, the hydrothermal reaction treatment is performed at a relatively high reaction temperature, so that the first reaction A trace amount of residue in the vessel can be completely decomposed by supercritical water oxidation. In the reaction step, the temperature in the second reactor is maintained at 400 ° C or higher and 650 ° C or lower. As a result, the unreacted material remaining in the intermediate treatment fluid can be completely hydrothermally treated to render it harmless.

In a preferred embodiment of the method of the present invention, the carbon dioxide concentration or oxygen concentration in the treatment gas obtained by gas-liquid separation of the treatment fluid is measured to find that the carbon dioxide concentration is below a predetermined concentration, or When the oxygen concentration is equal to or higher than the predetermined concentration, it is determined that the hydrothermal reaction treatment of the object to be treated contained in the first reactor is almost completed. This makes it possible to reliably detect the end time of the hydrothermal reaction process. Further, the reaction completion step is carried out when it is judged that the hydrothermal reaction treatment of the object to be treated is finished. When it is determined that the hydrothermal reaction treatment is completed, the reaction completion step is further carried out to completely detoxify the object to be treated and allow the treated fluid containing no harmful substance to flow out.

In the pre-reaction step and the reaction step, by supplying an alkaline aqueous solution to the first reactor, the acid in the material to be treated is neutralized to form a salt, and the corrosion of equipment downstream of the first reactor is caused. Can be prevented. Further, by supplying an aqueous solution of potassium hydroxide (KOH) as the alkaline aqueous solution, it is possible to generate a potassium salt having low adhesiveness and prevent clogging of equipment and pipes downstream of the first reactor.

In a preferred embodiment of the method of the present invention, the treated gas and the treated water are respectively stored once, and it is confirmed whether or not the emission standard is satisfied. When the emission standard is not satisfied, the treated water is returned to the first reactor or the second reactor for reprocessing, and when the treated gas does not satisfy the emission standard, the activated carbon adsorption treatment is changed to the treated gas. Give. As a result, it is possible to prevent the processing fluid that does not meet the discharge standard from being discharged to the outside. Here, the emission standard may be a standard that is publicly defined or a standard that is privately determined. On the other hand, when the treated water satisfies the emission standard, the treated water is subjected to desalting treatment if necessary, and reused as the initial filling water of the first reactor or the raw water of supercritical water or subcritical water. To do.

The apparatus and method of the present invention can be applied without limitation to the shape and properties of the object to be treated as long as the object to be treated is a solid substance, and particularly PCB contaminated solid substances, dioxin contaminated solid substances, agricultural chemicals, and agricultural chemical contaminated solid substances. It can be suitably applied to a hydrothermal reaction treatment of a solid matter to be treated containing a hardly decomposable organic substance such as a substance.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described specifically and in detail with reference to the accompanying drawings by way of example embodiments. Embodiment Example of Hydrothermal Reaction Processing Apparatus This embodiment example is an example of an embodiment of the hydrothermal reaction processing apparatus according to the present invention, and FIG. 1 is a flow showing the configuration of the hydrothermal reaction processing apparatus of the present embodiment example. It is a sheet. As shown in FIG. 1, a hydrothermal reaction treatment device 10 (hereinafter simply referred to as a device 10) includes a first reactor 12 which is a batch-type hydrothermal reactor and a tube-type second reactor as a second reactor. 14 and a processing fluid discharge system 16 for discharging the processing fluid flowing out from the second reactor 14.

The apparatus 10 further comprises a supercritical water supply system 18 for supplying supercritical water or subcritical water to the first reactor 12, and an alkali for supplying an aqueous potassium hydroxide (KOH) solution to the first reactor 12. An air supply system 22 for supplying air as an oxidant to the supply system 20 and the first reactor 12 and the second reactor 14 is provided.

The first reactor 12 is an openable and closable container-type reactor for accommodating an object to be processed and subjecting the object to a hydrothermal reaction treatment in a batch manner to let out an intermediate treatment fluid. Reactor main body 12a consisting of a vertical pressure-resistant container having a lid on the top, and a cylindrical inner cylinder whose upper part is opened and which stands upright concentrically from the bottom of the reactor main body 12a and whose inside is a hydrothermal reaction zone. 12b and. The inner cylinder 12b is provided with a plate-shaped support plate 12c that supports solid matter. A mixed fluid of supercritical water or subcritical water and air is introduced into the inner cylinder 12b from the bottom of the reactor body 12a, and rises in the inner cylinder 12b while coming into contact with the solid matter on the support plate 12c to cause a hydrothermal reaction. Then, the annular portion 12d between the reactor main body 12a and the inner cylinder 12b descends and flows out from the bottom of the reactor main body 12a as an intermediate treatment fluid. Further, by providing a sealing lid on the upper part of the inner cylinder 12b, the inner cylinder 12b is independently cut off from the region between the inner cylinder 12b and the reactor body 12a, and the inner cylinder inner fluid is provided inside the inner cylinder. A discharge pipe having an opening may be provided in the upper part of the inner cylinder 12b to discharge the processing fluid of the first reactor 12 to the second reactor 14.

Further, the first reactor 12 is the first reactor 12
A cylindrical first heating furnace 24 surrounding the outer periphery of the first reactor 12 is provided for heating the one accommodated therein. In addition, an internal heater may be provided around the inner cylinder 12a in the first reactor 12. The temperature in the first reactor 12 is 200 ° C. or higher and 374 ° C. or lower in the first stage of the treatment, and 374 ° C. or higher and 650 ° C. or lower in the second stage of the treatment.

The second reactor 14 is connected in series to the first reactor 12 by an intermediate processing fluid pipe 26 connected to the bottom of the annular portion 12d of the first reactor 12, and the first reactor 1
The intermediate treatment fluid flowing out of 2 is continuously and completely treated by a hydrothermal reaction to flow out as a treatment fluid. The 1st reactor 12 and the 2nd reactor 14 are connected only by piping, and piping components, such as an on-off valve, are not interposed. Therefore, troubles such as operation stop due to failure of piping parts do not occur,
It is possible to continue stable operation. In addition, the second reactor 14 includes a second heating furnace 2 that surrounds the entire outside of the second reactor 14 in order to heat the processing fluid in the second reactor 14.
Eight. The temperature of the second reactor is equal to or higher than the temperature of the first reactor 12, and is 400 ° C. or higher and 650 ° C. or lower.

The treatment fluid discharge system 16 includes a cooler 30 for cooling the treatment fluid flowing out from the second reactor 14, a pressure control valve 3 for controlling the pressures of the first reactor 12 and the second reactor 14.
2, and a gas-liquid separator 34 for gas-liquid separating the processing fluid is sequentially provided in the processing fluid pipe 36. The pressure control valve 32 is controlled by the pressure control device 40 based on the pressure measurement value measured by the pressure gauge 38 provided in the processing fluid pipe 36.
Also, the valve opening of the pressure control valve 32 is adjusted so that the pressure of the second reactor 14 is maintained at a predetermined pressure.

The processing gas separated by the gas-liquid separator 34 is
A process gas pipe 42 connected to the top of the gas-liquid separator 34 releases it to the atmosphere or sends it to the next step. The processing gas pipe 42 is provided with a gas analyzer 44 for monitoring the composition of the processing gas, particularly the oxygen concentration or the carbon dioxide concentration. Gas-liquid separator 34
A part of the treated water separated in step 1 is discharged to the outside from the treated water pipe 46 connected to the bottom of the gas-liquid separator 34, and the rest is passed through the first circulating water pipe 50 by the circulation pump 48 to the first reactor 12 And a second circulating water pipe 52 connected to a second air supply pipe 74, which will be described later, are circulated in the second reactor 14, respectively. The treated water pipe 46 has a composition of treated water, especially TOC.
A water analyzer 54 is provided to monitor concentration or specific organic matter.

The supercritical water supply system 18 heats the water tank 56, the water pump 58 for supplying water from the water tank 56, and the water sent by the water pump 58 to the temperature of the supercritical water or subcritical water. It has a water preheater 60 for raising the temperature, and a water supply pipe 62.
To supply supercritical water or subcritical water to the first reactor 12. The water supply pipe 62 joins the first circulating water pipe 50 from the gas-liquid separator 34 downstream of the water preheater 60. Although not shown, a hot water supply system for supplying water or supercritical water to the second reactor 14 to raise the temperature of the second reactor 14 to a supercritical water oxidation condition is provided. .

The alkali supply system 20 has an alkaline aqueous solution tank 64 for storing a potassium hydroxide aqueous solution as an alkaline aqueous solution, and an alkaline aqueous solution pump 66 for feeding the aqueous potassium hydroxide solution from the alkaline aqueous solution tank 64, and a water feeding pipe 62. The potassium hydroxide aqueous solution is sent to the first reactor 12 by the connected alkaline aqueous solution pipe 68. The air supply system 22 includes an air compressor 70, and includes a first air supply pipe 72 connected to the water supply pipe 62 and a second air supply pipe 74 connected to the intermediate treatment fluid pipe 26, and the first reactor 12 and the first reactor 12 Air is supplied to each of the two reactors 14 as an oxidant.

Embodiment Example of Batch Type Hydrothermal Reaction Treatment Method This embodiment example is an example of an embodiment of the hydrothermal reaction treatment method according to the present invention, in which the above-mentioned hydrothermal reaction treatment apparatus 10 is used for water treatment. It is a method of treating a solid substance impregnated with PCB as a substance to be treated by a thermal reaction. In the present embodiment example, first, the solid material impregnated with PCB is housed in the first reactor 12 and sealed. Next, the processing fluid pipe 32 is replaced with water by the low-pressure fresh water pump 80 immediately upstream of the pressure control valve 32. After confirming that the water surface is located up to the position of the replacement water discharge valve 81, the processing fluid pipe 32 downstream of the first reactor is replaced with water.
Further, if necessary, nitrogen is introduced into the first reactor 12 to pressurize it to a predetermined pressure. Next, the alkaline solution pump 6
6. The water pump 58 is started to supply a predetermined amount of initial filling water to the first reactor 12. Then start the water pump 58,
Water is supplied to the first reactor 12 while being heated by the water preheater 60. Next, the circulating water pump 42 is activated to circulate water through the first circulating water pipe 50 and the second circulating water pipe 52 to the first reactor 12 and the second reactor 14.

Then, the process proceeds to the pre-reaction step of the first reactor 12, the first reactor 12 is heated by the first heating furnace 24 to maintain the temperature at a predetermined temperature of 200 ° C. or higher and 374 ° C. or lower, and the subcritical water. Is supplied to hydrolyze the substance to be decomposed in the solid matter to lower the molecular weight. Before the pre-reaction step of the first reactor 12 or together with the pre-step step, the second reactor preparation step is performed. In the second reactor preparation step, the supercritical water supply system 18
And supercritical water and air are supplied to the second reactor 14 by the air supply system 22 to form a supercritical water reaction zone in which the temperature is maintained at a temperature of 400 ° C. or higher and 650 ° C. or lower in the second reactor 14. To do.

After the pre-reaction step and the second reactor preliminary heating step, the reaction step is started. In the reaction step, subcritical water and air are supplied to the first reactor 12 by the supercritical water supply system 18 and the air supply system 22 to accelerate the hydrolysis of an object to be treated, for example, PCB, in the first reactor 12. Subsequently, the intermediate treatment fluid generated by hydrolysis in the first reactor 12 is introduced into the second reactor 14 together with air, and the intermediate treatment fluid is subjected to supercritical water reaction treatment in the second reactor 14, It is made to flow out as a processing fluid.

When the material to be treated contains an acid-producing material such as PCB, an aqueous potassium hydroxide solution is supplied to the first reactor 12 by the alkali supply system 20 in the pre-reaction step and the reaction step. The acid generated by the hydrothermal reaction is neutralized to prevent corrosion of the equipment of the apparatus 10. Further, the acid neutralization reaction is completed in the first reactor 12,
It is not necessary to supply alkali to the second reactor 14, but alkali can be supplied if necessary. It should be noted that the potassium salt is less adhesive than the sodium salt, and the pipes and equipment are less likely to be blocked.

The treatment fluid flowing out from the second reactor 14 is cooled by the cooler 30 and separated into gas and liquid by the gas-liquid separator 34, and the treatment gas is discharged from the treatment gas pipe 42. Part is discharged to the outside, and the rest is circulated to the first reactor 12 and the second reactor 14 by the circulation pump 48.

The carbon dioxide concentration in the treated gas is measured by the gas analyzer 44, and when the carbon dioxide concentration falls below a predetermined concentration or when the oxygen concentration in the treated gas exceeds a predetermined concentration, the first reaction It is determined that the hydrothermal reaction treatment of the object to be treated contained in the vessel 12 is almost completed. In addition, T of treated water
By monitoring that OC is always 0 mg / l, complete decomposition of organic substances can be confirmed. And
When it is determined that the hydrothermal reaction treatment of the object to be treated is almost completed, the reaction completion step is performed. In the reaction completion step, the temperature in the first reactor 12 is raised to 374 ° C. or higher and 650 ° C. or lower, and supercritical water is supplied to allow the supercritical water reaction or the subcritical water reaction to proceed for a predetermined period of time to be treated. Thoroughly process things.

After carrying out the reaction completion step for a predetermined time,
Again, the carbon dioxide concentration in the treatment gas is measured by the gas analyzer 44, and it is confirmed that the carbon dioxide concentration becomes zero (%), and the hydrothermal reaction of the treatment object accommodated in the first reactor 12 Judge that the processing is completed. Then, the first reactor 1
2, the second reactor 14 and the treatment fluid outflow system 16 are cooled and decompressed, and then the first reactor 12 is opened to discharge the non-organic substances remaining in the first reactor 12. The hydrothermal reaction treatment of the object to be treated is completed through the above steps.

In this embodiment, it is preferable to temporarily store the treated gas and the treated water, respectively, and confirm whether or not the emission standard is satisfied. Then, when the treated water satisfies the discharge standard, the treated water is subjected to desalting treatment if necessary and reused as raw water for supercritical water or subcritical water. When the discharge standard is not satisfied, all the treated water is returned to the first reactor 12 and retreated. When the treated gas does not satisfy the emission standard, the treated gas is subjected to activated carbon adsorption treatment.

In the filling step, at least a part of the devices and pipes of the first reactor 12, the second reactor 14, and the treatment fluid discharge system 16 are filled with nitrogen gas or air instead of water,
The pressure may be increased to a predetermined pressure.

In the present embodiment, the object having a high PCB concentration is processed in the first reactor 12 at a relatively low reaction temperature, and the PCB is almost completely dechlorinated, but some organic residue remains. there is a possibility. Letting a processing fluid having a low organic matter concentration flow out from the first reactor 12 as an intermediate processing fluid,
The intermediate treatment fluid is continuously fed to the first reactor 1 by the second reactor 14.
By treating at a temperature higher than 2, it is possible to efficiently treat the solid matter to be treated. Also, since the second reactor preparation step is provided before the reaction step and the second reactor 12 is maintained in the standby state for the supercritical water reaction treatment, the time required for the pre-stage from the filling step to the reaction step is increased. Can be shortened,
The processing efficiency can be improved. Furthermore, the reaction completion step can completely and surely treat the PCB impregnated in the solid matter to render the solid matter harmless.

[0047]

EFFECTS OF THE INVENTION According to the present invention, as a reactor of a hydrothermal reaction treatment apparatus, an openable and closable container-type first reactor for accommodating a solid substance as an object to be treated and performing a hydrothermal reaction treatment in a batch system is provided. ,
A tube-type second reactor connected in series to the first reactor, wherein the intermediate treatment fluid flowing out from the first reactor is further subjected to continuous hydrothermal reaction treatment and finally discharged as a treatment fluid. As a result, an apparatus capable of efficiently treating a solid object to be treated by a hydrothermal reaction is realized. That is,
The first reactor is filled with a large amount of solid matter to be treated in a batch manner, and the intermediate treatment fluid flowing out from the first reactor is continuously treated in the second reactor to once. The processing efficiency can be improved by increasing the batch processing amount of. Further, since the treatment is performed in a batch system, if the clogging due to the precipitation of the inorganic substances does not occur during one treatment, no problem occurs in the operation of the apparatus, and stable operation can be performed. The method of the present invention realizes a hydrothermal reaction treatment method capable of efficiently and reliably performing a hydrothermal reaction treatment of a solid matter using the hydrothermal reaction treatment apparatus of the present invention.

[Brief description of drawings]

FIG. 1 is a flow sheet showing a configuration of a hydrothermal reaction treatment apparatus of an embodiment example.

FIG. 2 is a flow sheet showing the configuration of a conventional supercritical water reaction treatment device.

[Explanation of symbols]

10 Hydrothermal reaction treatment equipment 12 First reactor 14 Second reactor 16 Processing fluid discharge system 18 Supercritical water supply system 20 Alkali supply system 22 Air supply system 24 First heating furnace 26 Intermediate processing fluid pipe 28 Second heating furnace 30 cooler 32 Pressure control valve 34 gas-liquid separator 36 Processing fluid pipe 38 Pressure gauge 40 Pressure control device 42 Process gas pipe 44 gas analyzer 46 Treated water pipe 48 circulation pump 50 First circulating water pipe 52 Second circulating water pipe 54 Water Analyzer 56 water tank 58 water pump 60 water preheater 62 water pipe 64 Alkaline solution tank 66 Alkaline solution pump 68 Alkaline solution tube 70 Air compressor 72 First air supply pipe 74 Second air supply pipe 80 Conventional batch type supercritical water reactor 81 Batch type reactor 82 Water supply means 83 Air compressor 84-plate support plate 85 water tank 86 water pump 87 heat exchanger 88 heating furnace 89 water pipe 90 Air supply pipe 91 Outflow pipe 92 Gas-liquid separator 93 Pressure control device 94 Booster Pump 95 Gas release pipe 96 pressure gauge 97 Pressure control valve 98 CO concentration meter 99 water pipe

Claims (17)

[Claims] 1. A container-type first reactor which accommodates a solid substance as an object to be treated and which is subjected to hydrothermal reaction treatment to let the object to be treated to flow out an intermediate treatment fluid, and a first reactor in series. A hydrothermal reaction treatment device, comprising: a second reactor connected to the intermediate treatment fluid, which flows out from the first reactor, and which is further continuously subjected to hydrothermal reaction treatment to flow out as a treatment fluid. 2. The first reactor and the second reactor are respectively provided with a first heating means for heating the first reactor and a second heating means for heating the second reactor. The hydrothermal reaction treatment device according to. 3. The first reactor is provided with a supply means for supplying an aqueous alkali solution to the first reactor.
The hydrothermal reaction treatment device according to. 4. An openable and closable container-type reactor for accommodating a solid substance as an object to be treated, subjecting the object to a hydrothermal reaction treatment to let out an intermediate treatment fluid, and a first reactor in series. A second reactor connected to the intermediate treatment fluid, which flows out from the first reactor, to be subjected to continuous hydrothermal reaction treatment to flow out as a treatment fluid, and a treatment fluid to discharge the treatment fluid flowing out from the second reactor. A method for hydrothermally treating a solid matter by a hydrothermal reaction treatment apparatus having a discharge system and further having a first heating means for heating the first reactor and a second heating means for heating the second reactor. Therefore, the solid matter is housed in the first reactor, and then water is supplied to the first reactor to fill the first reactor, the second reactor, and the treatment fluid discharge system with water, and to set a predetermined pressure. Filling step of increasing the pressure to, and then heating the first reactor by the first heating means Supplying a supercritical water or a subcritical water and an oxidant to the second reactor before or with the pre-reaction step of hydrolyzing the organic matter in the solid matter to lower the molecular weight And a second reactor preparation step for forming a supercritical water reaction zone in the second reactor, which is maintained at a temperature equal to or higher than the temperature in the first reactor, and a pre-reaction step and a second reactor preparation step Then, hot water and, if necessary, an oxidant are supplied to the first reactor to accelerate the hydrolysis of the organic matter in the solid matter to flow out the intermediate treatment fluid, and subsequently to form a supercritical water reaction zone. First in the second reactor
And a reaction step of introducing the intermediate treatment fluid from the reactor and subjecting the intermediate treatment fluid to the supercritical water reaction treatment in the second reactor. 5. In the filling step, at least a part of the first reactor, the second reactor, and the equipment and piping of the processing fluid discharge system is filled with nitrogen gas or air instead of water, and the pressure is raised to a predetermined pressure. The hydrothermal reaction treatment method according to claim 4, wherein 6. The hydrothermal reaction treatment method according to claim 4, wherein in the pre-reaction step, the temperature in the first reactor is maintained at 200 ° C. or higher and 374 ° C. or lower. 7. The final step of the reaction process has a reaction completion step of maintaining the temperature in the first reactor at 374 ° C. or higher and 650 ° C. or lower for a predetermined time, and supplying supercritical water to the first reactor. The hydrothermal reaction treatment method according to any one of claims 4 to 6, wherein 8. The temperature in the second reactor is set to 4 in the reaction step.
The hydrothermal reaction treatment method according to any one of claims 4 to 7, characterized in that the temperature is maintained at 00 ° C or higher and 650 ° C or lower. 9. The carbon dioxide concentration or the oxygen concentration in the treatment gas obtained by gas-liquid separation of the treatment fluid is measured, and the carbon dioxide concentration is below a predetermined concentration or the oxygen concentration is above a predetermined concentration. 9. The hydrothermal reaction treatment method according to claim 4, wherein it is judged that the hydrothermal reaction treatment of the object to be treated contained in the first reactor is almost completed. 10. The hydrothermal reaction treatment method according to claim 9, wherein the reaction completion step is carried out at the stage when it is judged that the hydrothermal reaction treatment of the object to be treated is almost completed. 11. The hydrothermal reaction treatment method according to claim 4, wherein an alkaline aqueous solution is supplied to the first reactor in the pre-reaction step and the reaction step. 12. A potassium hydroxide (KOH) aqueous solution is supplied as the alkaline aqueous solution.
1. The hydrothermal reaction treatment method according to 1. 13. After the reaction step, the first reactor is cooled,
13. The process for hydrothermal reaction treatment according to claim 4, further comprising a reactor opening step of decompressing and then releasing the inorganic material remaining in the first reactor. 14. The hydrothermal reaction treatment method according to claim 4, wherein the treated gas and the treated water are temporarily stored respectively and whether or not the emission standard is satisfied is confirmed. 15. When the treated water satisfies the discharge standard, the treated water is subjected to a desalting treatment, if necessary, and reused as raw material water for supercritical water or subcritical water. Item 15. The hydrothermal reaction treatment method according to Item 14. 16. When the emission standard is not satisfied,
15. The hydrothermal reaction treatment method according to claim 14, wherein the treated water is returned to the first reactor or the second reactor for retreatment. 17. The hydrothermal reaction treatment method according to claim 14, wherein when the treatment gas does not meet the emission standard, the treatment gas is subjected to activated carbon adsorption treatment.