JP6737561B1 - Subcritical water treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a subcritical water treatment device capable of performing uniform treatment even if the size is increased. SOLUTION: A heating steam supply path 4 branches downstream of a remote control valve 6 and supplies heating steam into the reaction tank 3 from a plurality of places on the ceiling of the reaction tank 3. The heating steam supplied into the reaction tank 3 is at least 2 MPa and 300°C. On the other hand, the circulation path 5 is arranged in a labyrinth shape along the outside of the bottom surface of the reaction tank 3 while avoiding the extraction section 9. When the circulation path 5 is provided in the reaction tank 3, it interferes with the stirring device and forms a pool for the object to be treated, so that the circulation path 5 is arranged outside the bottom surface. [Selection diagram]

Description

The present invention relates to a treatment device for organic waste using subcritical water.

When organic waste is burned in an incinerator or heat recovery furnace to be incinerated, harmful substances such as greenhouse gases, dioxins, and nitrogen oxides, which cause environmental pollution, may be generated. Therefore, treatment using supercritical water having a temperature/pressure under supercritical water conditions (22.1 MPa or more and 374° C. or more) and subcritical water under subcritical water conditions (1-8 MPa, 100-300° C.) A method has been proposed.

Steam at 100° C. and 1 atmosphere is saturated steam, and steam under high temperature and high pressure is heated steam (superheated steam), and has a higher enthalpy than saturated steam at 100° C. and 1 atmosphere.

In Patent Document 1, as a treatment device for waste containing heavy metals, it is composed of a closed container, a steam ejecting means, a cooling means and a separation and recovery means. In addition, it is proposed to contain a Ca component raw material and a SiO 2 component raw material in an amount sufficient to form a 5CaO.6SiO2.5H2O crystal (tobermorite) for containing at least the heavy metals in the crystal structure.

Patent Document 2 discloses an apparatus for treating organic waste, which is capable of separating a treated waste and a liquid by a simple operation and collecting the treated waste continuously with an apparatus for treating the waste using high-temperature and high-pressure steam. It is disclosed.

In Patent Document 3, as a fulvic acid production apparatus, a closed container having a closed space for containing a raw material that is a wood chip therein, and a steam ejection means for ejecting high-temperature and high-pressure steam that is subcritical water into the closed container And a structure having a discharge port provided on the bottom side of the closed container and having an opening/closing mechanism, and a separation/collection means for separating and collecting the raw material and the liquid processed only by the direct discharge operation from the discharge port have been proposed. ing.

Patent Document 4 discloses a heating device using heated steam (superheated steam) used for heat treatment of industrial waste. Specifically, the flow path of the heating device for heating an object to be heated that passes through the flow path is made of a high resistance material having an electric resistivity of 100 μΩ·cm or more, and has a hollow shape whose outside is covered with a heat insulating layer. The hollow part of the heat generating pipe has been proposed.

Patent Document 5 discloses a reaction apparatus for organic substances or the like using supercritical water or subcritical water. This reactor is a means for compressing water vapor to obtain supercritical water or subcritical water, a means for contacting the supercritical water or subcritical water with a substance to be reacted such as an organic substance to carry out a chemical reaction, and this chemical And a means for decompressing water containing a product generated by the reaction to reduce the pressure.

Patent Document 6 discloses a steam plant that uses supercritical water by extracting at least one of supercritical water, subcritical water, and steam to obtain supercritical water. This steam plant is equipped with a boiler water supply system and a steam supply system, and obtains supercritical water by extracting supercritical water, subcritical water or steam from any part of the boiler, the boiler water supply system or the steam supply system. Water removal device, organic matter decomposition reaction tank for oxidative decomposition of organic matter using supercritical water obtained by this supercritical water removal device as a solvent, and removal of treated water generated by oxidative decomposition of organic matter And a supercritical water organic matter treatment facility having a device.

WO2013/150660 WO2006/126273 Japanese Patent Laid-Open No. 2019-044029 JP, 2010-214364, A JP 2002-263465 A JP, 2002-248334, A

The device disclosed in the above-mentioned patent document operates efficiently if it is relatively small (6 m ³ or less). However, in the case of a large-capacity reaction tank, the heating steam does not reach the whole, and the subcritical water treatment reaction does not proceed partially and the decomposition treatment tends to be non-uniform.

Further, there is a problem that the heated steam removes heat from the processed material, and the subcritical water passes through the saturated steam to become hot water and accumulates in the reaction tank.

In order to solve the above problems, it is difficult to uniformly treat heated steam (high-temperature high-pressure steam) having a temperature higher than that of subcritical water, but the present invention is based on the finding that uniform treatment is possible by combining with subcritical water. I made it.

Specifically, the subcritical water treatment apparatus according to the present invention is a boiler that generates saturated steam, a heating steam generator that converts saturated steam from this boiler into heating steam in a subcritical water state, and this heating steam. From the heating steam supply path for supplying the heating steam from the generator from the ceiling of the reaction tank, and the circulation path for returning the heating steam from the heating steam generator arranged along the outside of the bottom surface of the reaction tank to the boiler. Composed.

It is preferable that the heating steam supply path is provided with a remote control valve that opens the heating steam supply path only during the treatment, while the heating steam is constantly supplied to the circulation path.

In addition, the shape of the reaction tank is a horizontal cylinder with both sides closed, and the rotation shaft and stirring blades are housed in this reaction tank.The stirring blades stir the object to be processed when rotating in the forward direction and rotate in the reverse direction. Sometimes, the structure can be such that the object to be processed is scraped out.

According to the present invention, even if the reaction tank is upsized, the heat of the heated steam is locally removed by the object to be treated such as waste, and the water is unlikely to become water, so that the decomposition reaction is uniformly carried out in the entire reaction tank. In addition, since the reaction tank can be upsized, the amount of waste processed per day can be significantly increased.

In particular, by constantly heating the inside of the reaction tank with the heating steam flowing from the outside of the bottom surface of the reaction tank in the circulation path, it is possible to maintain a uniform temperature throughout the reaction tank, and from the ceiling of the reaction tank only during processing. Since it suffices to supply heated steam, thermal efficiency is improved.

In addition, the blade structure of the stirring device placed in the reaction tank is such that the object to be processed is stirred when rotating in the forward direction and is scraped out when rotating in the reverse direction, so that the shape of the reaction tank has a large central part. Even if it is not a rugby ball shape with a diameter but a simple tubular shape, it is difficult for the object to be treated or the substance after treatment to remain inside.

Front view of the subcritical water treatment apparatus according to the present invention Bottom view of the subcritical water treatment device Side view of the subcritical water treatment device Diagram illustrating the stirring device arranged in the reaction tank Perspective view of stirring unit

Embodiments of the present invention will be described below with reference to the accompanying drawings.
The subcritical water treatment device is a boiler 1 that generates steam in a subcritical water state (1 to 2 MPa, 100 to 250° C.), and heating steam generation that converts the subcritical water from the boiler 1 into heating steam of high temperature and high pressure. The apparatus 2, the heating steam supply path 4 for supplying the heating steam from the heating steam generator 2 from the ceiling of the reaction tank 3, and the heating steam generator 2 arranged along the outside of the bottom surface of the reaction tank 3 A circulation path 5 for returning the heated steam of 1 to the boiler 1. In addition, it is safe to add a device for generating saturated steam and superheated steam to the boiler 1.

Remotely operated valves 6 and 7 are provided in the heating steam supply path 4 and the circulation path 5, and the remotely operated valve 6 is opened only while the waste is decomposed, and the remotely operated valve 7 stops the apparatus for a long time. Is always open and the temperature of the entire reaction tank 3 is kept above a certain level.

The reaction tank 3 has a tubular shape with both ends closed, an inlet 8 for an object to be treated such as industrial waste is provided at the top, and an outlet 9 for an object to be treated after reaction is provided at the bottom. It is provided. The take-out section 9 also functions as a drain discharge section.

The heating steam supply path 4 branches off on the downstream side of the remote control valve 6 and supplies the heating steam into the reaction tank 3 from a plurality of places on the ceiling of the reaction tank 3. The heating steam supplied into the reaction tank 3 is at least 2 MPa and 300°C.

The circulation path 5 branches off on the downstream side of the remote control valve 7, and is arranged in a labyrinth shape along the outside of the bottom surface of the reaction tank 3 while avoiding the extraction section 9. The return side to the boiler 1 is located below the valve 7 and has a structure for preventing the water hammer phenomenon. When the circulation path 5 is provided in the reaction tank 3, it interferes with the agitator and forms a pool for the object to be treated. Therefore, the bottom surface has a double structure and is arranged with a heat insulating material therein. However, in order to increase the efficiency of heat radiation (heat transfer), the distance from the surface of the reaction tank 3 may be made as small as possible and contact may be made. In addition, a radiator structure may be used to enhance heat exchange.

A stirring device 10 is arranged in the reaction tank 3. The stirrer 10 has support rods 12 attached to a rotary shaft 11 inserted in the center of the reaction tank 3 at predetermined intervals, and a bending plate 14 attached to the tip of the support rod 12 via a spring 13.

As shown in FIG. 5, the bending plate 14 includes a stirring unit 15 and a scraping unit 16, and the outer surface of the scraping unit 16 is pressed against the inner surface of the reaction tank 3 by the elastic force of the spring 13. Then, the object to be treated is stirred in the reaction tank 3 when rotating in the forward direction, and the object to be treated is scraped out when rotating in the reverse direction.

For example, in FIG. 1, the stirrer 10 is divided into the right stirrer 10 and the left stirrer 10, and the bending plates 14 of the respective stirrers 10 are reversed in direction (the directions of the stirrer 15 and the scraper 16). By reversing), stirring and scraping can be effectively performed.

In the above, while the entire reaction tank 3 is uniformly heated by the heated steam flowing in the circulation path 5, the object to be treated such as industrial waste is charged into the reaction tank 3 from the charging section 8 and simultaneously operated remotely. The valve 6 is opened, and heated steam (subcritical water) is supplied from the heated steam supply path 4 into the reaction tank 3.

The substance to be treated in the reaction tank 3 is stirred and reduced in molecular weight under the conditions of 1 to 8 MPa and 100 to 300°C.
For example, municipal waste is hydrothermally decomposed into compost, amino acids are produced from fish residues and livestock, and wood is used as feed to produce fulvic acid.

DESCRIPTION OF SYMBOLS 1... Boiler, 2... Heating steam generator, 3... Reaction tank, 4... Heating steam supply path, 5... Circulation path, 6, 7... Remote control valve, 8... Injecting part of processed material, 9... Processing object Take-out part, 10... stirring device, 11... rotating shaft, 12... support rod, 13... spring, 14... bent plate, 15... stirring part, 16... scraping part.

Claims (3)

A boiler that generates steam in the subcritical water state, a heating steam generator that converts the steam in the subcritical water state from the boiler to high-temperature, high-pressure heating steam, and a heating steam from the heating steam generator in a reaction tank Subcritical water comprising a heating steam supply path supplied from the ceiling part of the reactor and a circulation path arranged along the outside of the bottom surface of the reaction tank to return the heating steam from the heating steam generator to the boiler. Processing equipment. The subcritical water treatment apparatus according to claim 1, wherein the heating steam supply path for supplying the heating steam from the ceiling of the reaction tank is provided with a remote control valve that opens the heating steam supply path only during processing. A subcritical water treatment device characterized in that The subcritical water treatment apparatus according to claim 1 or 2, wherein the reaction tank is in the shape of a horizontal cylinder with both sides closed, and a rotary shaft and a stirring blade are housed in the reaction tank. Is a sub-critical water treatment device having a structure in which a material to be treated is agitated when it is rotated in the forward direction and is scraped out when it is rotated in the reverse direction.

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