JP3700845B2 - Organic waste heat treatment equipment - Google Patents

Description

【００１３】
【発明の効果】
本発明によって、固形物を含有する有機性廃棄物を対象として１００℃以上の加熱処理を行う装置において、加熱処理中の反応槽内部の圧力を大気圧以上の高圧に保持し、且つ連続的に処理を行うことができ、複雑な運転制御のないシンプルな装置を構築することができた。
【図面の簡単な説明】
【図１】本発明の加熱処理装置の一例を示すフロー構成図。
【図２】本発明の加熱処理装置の他の例を示すフロー構成図。
【図３】本発明の加熱処理装置の別の例を示すフロー構成図。
【符号の説明】
１：原料貯留槽、２：給泥ポンプ、３：反応槽、４：減圧ポンプ、５：排泥槽、６：排泥ポンプ、７：熱交換器、８：蒸気供給弁、９：水位計、１０：圧力計、１１：温度計、１２：余剰蒸気、２１：原料、２２：加温用蒸気、２３：脱臭ダクト、２４：発酵槽[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic waste heat treatment apparatus, and more particularly to a treatment apparatus that thermally decomposes organic waste containing solid matter under pressure.
[0002]
[Prior art]
Incineration treatment is widely used in the treatment of organic waste. Incineration is an extremely excellent method for reducing the final disposal amount of waste because all organic components in the waste are converted into carbon dioxide gas. However, in recent years, new incinerators have become difficult to install due to problems such as dioxins, and various alternative technologies such as gasification and melting, methane fermentation, and composting have been proposed. Among them, methane fermentation is attracting attention because it can recover energy as electric power by combining with power generation equipment at the same time as volume reduction.
[0003]
Among organic waste generated in Japan, biological treatment sludge generated in sewage treatment plants and septic tanks accounts for about 1/4. As described above, the merit of applying methane fermentation to these biologically treated sludges is great. However, the solid matter decomposition rate of biologically treated sludge in methane fermentation is assumed to be about 30 to 40% on a single basis, and the effects of volume reduction and energy recovery are limited at present.
Therefore, as a means for improving the solids decomposition rate, there is a method of performing pretreatment such as crushing, chemical addition, and heat treatment before the methane fermentation. In this heat treatment method, it is known that the sewage surplus sludge is treated at a temperature of 150 to 180 ° C. for 30 minutes, so that the solid matter decomposition rate becomes 50% or more. Other benefits of heat treatment include: (1) recovered heat can be used for treatment, (2) safe because chemicals are not used, and (3) pathogenic microorganisms contained in sludge are surely rejected. (4) Since the dewaterability of the treated sludge is improved, the dewatering flocculant can be saved.
[0004]
When organic waste is heat-treated at 100 ° C. or higher, in order to continuously treat the organic waste, it is necessary to attach a pressure holding means at the outflow part in order to keep the pressure inside the reaction tank at a high pressure of atmospheric pressure or higher. There is. In order to maintain the inside of the reaction tank at atmospheric pressure or higher, it is necessary to install a pressure reducing valve or the like in the outflow pipe to form pressure holding means. However, this means is difficult to apply because there is a risk that the piping, particularly the pressure reducing valve, etc. may be blocked by the solids contained in the object to be treated.
In addition, in order to perform batch processing, (1) the inside of the reaction tank is damaged by a large force temporarily applied during mud discharge or heating. (2) Pressure, temperature and water level detection There is a problem that, for example, it is necessary to perform operation or frequent opening / closing operation of the valve, so that complicated operation control is required, and the initial cost of the apparatus is increased.
[0005]
[Problems to be solved by the invention]
The present invention solves the problems of the prior art and provides a heat treatment apparatus capable of maintaining pressure by a simple means without using a pressure reducing valve that may be clogged when heat treating organic waste. Is an issue.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, in the present invention, a heat treatment apparatus having a reaction vessel capable of continuously heat-treating organic waste containing solids under pressure, the reaction vessel , possess a reduced pressure pump for discharging the sludge feeding pump and pressure treated to introduce a processing object, the type of the fed-mud pump vacuum pump, organic waste characterized by positive displacement pump der Rukoto This is a product heat treatment apparatus.
In the heat treatment apparatus, heat treatment in anti応槽, the reaction temperature 100 ° C. to 200 DEG ° C., may be carried out in the following residence time of 3 hours.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is intended for organic waste containing 1 to 20% of solid matter, and in an apparatus for performing heat treatment at 100 ° C. or higher, the pressure inside the reaction tank during heat treatment is maintained at a high pressure of atmospheric pressure or higher. In addition, it is an apparatus that performs processing continuously.
In this invention, in order to heat-process a process target object under the high pressure above atmospheric pressure continuously, the decompression pump is arrange | positioned in the outflow part of the reaction tank. The type of mud pump and vacuum pump is, for example, a positive displacement pump such as a single screw pump, roots pump, gear pump, etc. The internal pressure is maintained at a high pressure, and a temperature drop due to a pressure drop can be prevented.
In addition, since the object after treatment is at a temperature of 100 ° C. or more and a pressure of atmospheric pressure or more, it boils when it is released under normal pressure, the temperature drops to around 100 ° C., and at the same time, excess temperature energy is converted into steam. Converted. Since this phenomenon occurs downstream of the vacuum pump, a mud tank is installed, and the excess steam at the top of the mud tank is returned to the raw material storage tank, where it is used for heating the raw material, thereby saving heating energy. be able to. Furthermore, a heat exchanger is provided in the outflow part of the sludge tank, and the remaining heat can be reused by using the recovered heat for heating the boiler feed water.
[0008]
Hereinafter, the present invention will be described in detail with reference to the drawings.
FIG. 1 is a flowchart showing an example of the processing apparatus of the present invention.
In the figure, 1 is a raw material storage tank, 2 is a mud feed pump, 3 is a reaction tank, 4 is a decompression pump, 5 is a mud tank, 6 is a mud pump, and 7 is a heat exchanger.
The operation of the processing apparatus of the present invention will be described with reference to FIG. 1. After the raw material 21 is once stored in the raw material storage tank 1, it is sent to the reaction tank 3 by the mud feed pump 2. In the reaction tank 3, the raw material 21 is heated by the heating steam 22 and heat-treated at a temperature of 100 to 200 ° C. In order to set the temperature condition in the reaction vessel 3 to a predetermined condition, the amount of steam is controlled by the steam supply valve 8 linked to the thermometer 11. The heat-treated raw material is discharged to the sludge tank 5 through the decompression pump 4. In that case, since the inside of the mud tank 5 communicates with the outside through the raw material storage tank 1 and the deodorizing duct 23, the pressure is almost close to atmospheric pressure and cannot be 100 ° C. or higher. Therefore, boiling occurs in the mud tank 5 and excess energy becomes surplus steam 12. This surplus steam is blown into the raw material storage tank 1 through a pipe connected to the raw material storage tank 1, and is used for preliminary heating of the raw material 21. The raw material thus treated is transferred from the mud pump 6 to the fermenter 24 through the heat exchanger 7.
[0009]
FIG. 2 is a flowchart showing another example of the processing apparatus of the present invention. In FIG. 2, the raw material 21 is supplied from the raw material storage tank 1 to the reaction tank 3 by the mud feed pump 2. The reaction vessel 3 is heated by the steam 22. Heating is performed by controlling the steam supply valve 8 according to the indicated value of the thermometer 11. The raw material after the heat treatment is supplied to the sludge tank 5 through the decompression pump 4. A heat exchanger 7 is installed on the suction pipe of the mud supply pump 2 and the suction side of the decompression pump 4 to recycle the heating energy. In the sludge tank 5, since the pressure is reduced, surplus steam 12 is generated, so that it is supplied to the raw material storage tank 1 and used for heating the raw material 21.
[0010]
FIG. 3 is a flowchart showing another example of the processing apparatus of the present invention. In FIG. 3, the raw material 21 is supplied from the raw material storage tank 1 to the reaction tank 3 by the mud feed pump 2. The reaction vessel 3 is heated by the steam 22. Heating is performed by controlling the steam supply valve 8 according to the indicated value of the thermometer 11. The raw material after the heat treatment is supplied to the fermenter 24 through the vacuum pump 4. A heat exchanger 7 is installed on the discharge pipe of the mud supply pump 2 and the suction side of the decompression pump 4 to reuse the heating energy.
[0011]
【Example】
Hereinafter, the present invention will be specifically described by way of examples.
Example 1
Table 1 shows the results of heating cow dung with a screw press dehydrator for 30 minutes at 150 ° C. and the amount of gas generated when methane fermentation was performed on the untreated juice after treatment. The apparatus used a single screw pump for the mud supply pump 2 and the decompression pump 4. The effective capacity of the reaction tank 3 is 0.1 m ³ .
As a result of the heat treatment, the polymer compound contained in the cow dung juice was reduced in molecular weight, thereby increasing the soluble COD and slightly reducing the amount of solids. When the untreated squeezed liquid and the heat-treated squeezed liquid were subjected to methane fermentation, the heat-treated squeezed liquid was able to generate 1.5 times as much methane as the untreated one.
[0012]
[Table 1]

[0013]
【The invention's effect】
According to the present invention, in an apparatus for performing heat treatment at 100 ° C. or higher for organic waste containing solid matter, the pressure inside the reaction tank during the heat treatment is maintained at a high pressure of atmospheric pressure or higher and continuously. It was possible to construct a simple device that could perform processing and had no complicated operation control.
[Brief description of the drawings]
FIG. 1 is a flow configuration diagram showing an example of a heat treatment apparatus of the present invention.
FIG. 2 is a flow configuration diagram showing another example of the heat treatment apparatus of the present invention.
FIG. 3 is a flow configuration diagram showing another example of the heat treatment apparatus of the present invention.
[Explanation of symbols]
1: Raw material storage tank, 2: Mud feed pump, 3: Reaction tank, 4: Pressure reduction pump, 5: Waste mud tank, 6: Mud pump, 7: Heat exchanger, 8: Steam supply valve, 9: Water level gauge 10: Pressure gauge, 11: Thermometer, 12: Surplus steam, 21: Raw material, 22: Steam for heating, 23: Deodorizing duct, 24: Fermenter

Claims (2)

A heat treatment apparatus having a reaction tank capable of continuously heat-treating organic waste containing solid matter under pressure, the reaction tank comprising a mud feed pump for introducing a treatment object and a heating tank. possess a reduced pressure pump for discharging pressure treated, type of the fed-mud pump vacuum pump, heat treatment apparatus of organic waste characterized by positive displacement pump der Rukoto. The heat treatment in the reaction vessel, the reaction temperature 100 ° C. to 200 DEG ° C., a heat treatment apparatus of organic waste according to claim 1 Symbol placement and performing a residence time of 3 hours following conditions.

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