Organic waste treatment system

Abstract

[Object] To provide an organic waste treatment system in which general wastes from home, ordinary offices, and the like as well as industrial wastes including sludge, waste plastics, and the like can be subjected to treatment such as decomposition by a hydrothermal reaction under a subcritical water condition and in which treated wastes can be taken out in a dried state, sorted, and recycled.[Approach] In a waste treatment system for hydrolyzing organic wastes while stirring the wastes under a high-temperature and high-pressure environment and thermally decomposing or carbonizing the wastes in a double-walled pressure-resistant container 1, the system includes at least: water vapor supply means 9a for supplying high-heat saturated water vapor into the container 1; pressure regulating means 10 for regulating pressure in the container 1 by using an on-off valve; and stirring means 6 having a shaft 7 for stirring the charged wastes in the container 1 and provided to penetrate the container 1 and the system includes the steps of: hydrolyzing the wastes while adjusting temperature to 230° C. or higher and pressure to 3 MPa in the container 1 and stirring the wastes and thermally decomposing or carbonizing the wastes; adjusting the pressure in the container 1 to atmospheric pressure or lower and discharging the treated wastes out of the container while maintaining a dried state of the wastes; and sorting the discharged treated wastes and forming at least one of fertilizer, feed, and auxiliary fuel depending on types of the wastes.

Description

TECHNICAL FIELD[0001]The prevent invention relates to an organic waste treatment system in which general wastes from home, ordinary offices, and the like as well as industrial wastes including sludge, waste plastics, and the like can be subjected to treatment such as decomposition by a hydrothermal reaction under a subcritical water condition and in which treated wastes can be taken out in a dried state, sorted, and recycled.BACKGROUND TECHNIQUE[0002]In a prior-art organic waste treatment system, wastes to be treated are separated in advance and the separated wastes are respectively charged into treatment apparatuses designed according to types of the wastes. For example, the waste plastics are charged into and treated in a plastic-specific treatment apparatus, rubber such as waste tires is charged into and treated in a rubber-specific treatment apparatus, waste newspaper, wastepaper, and the like are charged into and treated in a treatment apparatus for paper, and garbage is charge...

AI Technical Summary

Benefits of technology

"The present invention provides an organic waste treatment system that can treat various types of organic wastes, including industrial wastes and general wastes, by hydrolysis and thermally decomposing them under high-temperature and high-pressure conditions. The system includes a pressure regulating means, a water vapor supply means, and a stirring means for mixing and stirring the wastes in a double-walled pressure-resistant container. The treated wastes can be discharged in a dried state and can be recycled or formed into auxiliary fuel. The system can also forcibly discharge water vapor to generate power. The invention utilizes the hydrothermal reaction under the subcritical saturated vapor pressure and does not discharge inner air before treatment."

Problems solved by technology

However, because the treatment apparatuses are designed according to the types of the wastes and how to treat them as described above, the treatment apparatus for the waste plastics cannot be used for treatment of rubber or garbage and the treatment apparatus for making feed and fertilizer cannot be used for treatment of the waste plastics, for example.

However, it is close to impossible for local small municipalities to have so many treatment apparatuses.

Moreover, not all of wastes can be easily separated into the waste plastics, rubber, wastepaper, garbage, and the like.

Especially because composite materials are used everywhere in recent products and many of the products cannot be separated easily even by disassembly.

If they are treated by the above treatment apparatuses, the apparatuses break.

However, many of wastes collected as burnable wastes are not recommended for incineration in an incinerator.

However, microbes and bacteria propagate in such litter and they may not die but be released into the atmosphere together with smoke exhaust or remain in incineration ash if the litter is incinerated in an incinerator.

In recent years, incineration of wastes in incinerators is subjected to criticism from a viewpoint of global environment protection and the incineration of waste plastics in the incinerators may damage the incinerators or generate harmful substances such as dioxin and is therefore strictly restricted by laws, ordinances, and the like.

Because they are of a continuous type, the apparatus becomes complicated.

Because the set temperature is as high as 500° C. or higher and the set pressure is as high as 5 MPa to 22 MPa, it is difficult and expensive to develop the apparatus resistant to such temperature and pressure.

Because treatment conditions of subcritical water suitable for an oxidative decomposition reaction are temperature of 250° C. or higher and treatment pressure of 5 to 10 MPa, it is difficult and too expensive to develop the apparatus for continuously performing oxidation under these conditions.

As a result, water vapor returns to a state of water to make the treated wastes swamped and make it difficult to take the wastes out of the apparatus.

Recycling of the treated wastes requires drying of the wastes again and is too expensive.

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