JP3370859B2 - Waste plastic processing and power generation system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a treatment / power generation system for a plastic composite material such as waste FRP, and more particularly to a treatment / power generation system suitable for the treatment of a plastic composite material such as waste FRP using high temperature and high pressure water. .

[0002]

2. Description of the Related Art Although it is difficult to dispose of plastic composite materials such as waste FRP because glass fiber is contained as a reinforcing material, it is mainly used for FRP ships and bathtubs due to its good functionality, and therefore the production amount. Is increasing,
Thirty years have passed since it was put into practical use. As a result, the treatment of plastic composite materials such as waste FRP that have been used up has become a serious problem.

An incinerator for waste FRP ships has been developed by the Ministry of Transport, and basic technology for utilizing the combustion heat of waste FRP has been developed.

On the other hand, research and development of a steam-added pyrolysis method, which is capable of decomposing plastic composite materials such as waste FRP into components and reusing them, have also been conducted. Among them, particularly, high-temperature high-pressure water, which is a high-pressure steam, in particular, the water-added pyrolysis method using supercritical water is capable of decomposing into a raw material of plastics because a reaction that does not occur at atmospheric pressure occurs and various efforts are being made. There is. The former aims at replacing plastic composite materials such as waste FRP with heat, and therefore is self-sustaining in terms of energy. On the other hand, the latter aims at returning to the raw material, but does not consider the energy source for industrially producing high temperature and high pressure water.

[0005]

The above-described combustion processing technology for the plastic composite material such as waste FRP can obtain heat energy with the processing of the plastic composite material such as waste FRP. Recycling is difficult because the glass components etc. in the plastic composite material are mixed and solidified to form combustion residues.

On the other hand, although the technique of decomposing plastic composite materials such as waste FRP with high temperature and high pressure water, especially supercritical water, can be obtained in a form that can be decomposed into raw materials and can be reused, but secures a heat source for producing high temperature and high pressure water. There is a need. Further, there is a problem that heat recovery and water recovery of the high temperature and high pressure water after the high temperature and high pressure water separation are not considered.

A first object of the present invention is to use waste FRP such as waste FRP to produce high-temperature high-pressure water by using the heat of combustion of ordinary waste plastics, and when incinerated, the unburned glass components and the like become residues. It is an object of the present invention to provide a waste plastic treatment / power generation system that can appropriately treat composite plastics such as the above with the high temperature and high pressure water according to the characteristics of the plastics.

A second object of the present invention is to generate power with surplus high-temperature high-pressure water, recover the heat such as combustion air preheat and feed water preheat with the high-temperature high-pressure water after use, and finally recover the water. It is to provide a plastic processing and power generation system.

A third object of the present invention is to provide a waste plastic treatment / power generation system which secures an energy source and utilizes the unused energy of waste plastic containing a plastic composite material such as waste FRP. .

[0010]

In order to achieve the above object, the waste plastic treatment / power generation system of the present invention is configured as follows. High-temperature high-pressure water decomposition equipment that decomposes composite plastics containing glass fiber and other reinforcing materials with high-temperature high-pressure water, thermal decomposition equipment that decomposes ordinary waste plastics, and harmful gas from the fluid fuel generated by this thermal decomposition equipment. And a device for removing soot and dust, a combustor that creates a heat source for combusting the fluid fuel that comes out of the device to create high-temperature high-pressure water, a boiler that creates high-temperature high-pressure water by the heat of combustion in this combustor, high-temperature high-pressure It consists of a power generation system using a steam turbine that generates water. Furthermore, a pure water production device is provided, and the high temperature and high pressure water that has passed through the high temperature and high pressure water decomposition device and the decomposed gas-liquid mixture are used as the heat sources of the thermal decomposition device, and combustion air preheating, makeup water preheating, feed water preheating, waste FRP preheating, steam turbine After recovering heat by reheating or steam turbine extraction heating, etc., condensate is used to collect water and make pure water in a pure water production device to make up water or waste FR.
It is supplied as the mother liquor of the slurry when P is supplied.

Further, a high-temperature and high-pressure water decomposing device for decomposing a composite plastic containing a reinforcing material such as glass fiber with high-temperature and high-pressure water, and a thermal decomposition device for decomposing ordinary waste plastics,
A removal device for removing harmful gas and dust from the fluid fuel generated by this thermal decomposition device, a combustor for driving the gas turbine by burning the fluid fuel discharged from the removal device,
Gas turbine power generation system driven by combustion gas of combustor, boiler that produces high temperature and high pressure water by exhaust heat of gas turbine,
It consists of a power generation system using a steam turbine that uses high-temperature, high-pressure water to generate power. Furthermore, a pure water production device is provided, and the high temperature and high pressure water that has passed through the high temperature and high pressure water decomposition device and the decomposed gas-liquid mixture are used as the heat sources of the thermal decomposition device, and combustion air preheating, makeup water preheating, feed water preheating, waste FRP preheating, steam turbine After recovering heat by reheating or steam turbine extraction heating, etc., the water is condensed to collect water, which is then made into pure water in a pure water production apparatus and supplied as makeup water or a mother liquor of the slurry when supplying waste FRP.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of the present embodiment.

As shown in FIG. 1, a waste FRP high-temperature high-pressure water decomposition treatment / power generation system using waste plastic pyrolysis fluid fuel of this embodiment is roughly divided into a steam turbine system and a high-temperature high-pressure water utilization system. There is.

The system according to the present embodiment is composed of waste plastic 3
Thermal decomposition device 24 for thermally decomposing 1 and thermal decomposition device 24
Air system 29 for supplying thermal decomposition air to the thermal decomposition apparatus 2
4, a steam system 28 for supplying thermal decomposition steam, a heat exchanger 32 for providing thermal decomposition heat to the thermal decomposition device 24, a harmful gas / dust removal device 25 for removing harmful gas and dust from the thermal decomposition device 24. An exhaust heat recovery device 27 in which a combustor for burning the fluid fuel generated by the thermal decomposition device 24 and a device for recovering the exhaust heat of the combustion heat are integrated, and the combustion heat is recovered in the exhaust heat recovery device 27 from the water supply. Boiler 5 consisting of an economizer for producing steam, an evaporator and a superheater 5, an air preheater 46 installed in the exhaust heat recovery device 27 to preheat the combustion air 1, and steam driven by steam emitted from the boiler 5 Turbine 33, generator 34 driven by steam turbine 33 to generate electric power, condenser 12 for condensing steam discharged from the outlet of steam turbine 33, condensate of condenser 12 and replenishment from pure water production apparatus 15. water The inflowing condensate tank 11, the condensate preheater 39 for preheating the water from the condensate tank 11, the deaerator 9 for deaerating the condensate preheated by the condensate preheater 39, and the deaerator 9 are injected. Steam turbine extraction 10 from the steam turbine 33
Water from the heater 23 and the deaerator 9 for heating the boiler 5
To control the amount of the high temperature high pressure water extraction 35 of the steam turbine 4, a valve 13 for releasing the fluctuation of the high temperature high pressure water extraction 35 of the steam turbine 33, and the steam that has passed through the valve 13 is recovered. Water condenser 1
6, a valve 7 for controlling steam used in the high-temperature high-pressure water decomposition device 19, a high-temperature high-pressure water decomposition device 19 using the high-temperature high-pressure water extraction 35 of the steam turbine 33, a high-temperature high-pressure water decomposition device 19 plastic such as waste FRP Composite material 1
Preparation tank 17 for preparing water in a slurry form by mixing water from the water tank 50 and plastic composite material 18 such as waste FRP to supply 8 and water and waste FRP from the preparation tank 17 to the high-temperature high-pressure water decomposition apparatus 19. Slurry supply pump 4 for supplying mixed slurry of plastic composite material of
1, a gas separator 20 for separating a mixture 44 of high-temperature high-pressure water leaving the high-temperature high-pressure water decomposer 19 and a decomposed product into a gas and a solid-liquid,
Heat exchanger 37 for heating a plastic composite material mixture such as waste FRP to be separated with a part of the high temperature / high pressure water / gas mixture 45 leaving the gas separator 20, the high temperature / high pressure water / gas leaving the gas separator 20 A water tank 50 for storing water after using a part of the mixture 45 as a heat source for the heater 23 and the condensate preheater 39, a pure water producing device 15 for converting the water in the water tank 50 into pure water, and water for the pure water producing device 15 It mainly comprises a pure water supply pump 14 for supplying the condensate tank 11, a blower 3 for feeding the combustion air 1 into the exhaust heat recovery device 27, and an air preheater 46 for preheating the air discharged from the blower 3. .

The system of the present embodiment thus constructed operates as follows. In the thermal decomposition device 24,
The preheated air supplied from the air system 29 and the steam supplied from the steam system 28 are injected into the heat exchanger 32 to maintain the temperature at a maximum of 350 to 450 ° C. to thermally decompose the waste plastic 31. To do. Device 25 for removing harmful gas and dust from the fluid fuel generated by this thermal decomposition
The soot dust and the corrosive gas such as chlorine gas are removed by using the exhaust heat recovery device 27 as clean fuel, and the boiler 5 generates high temperature and high pressure water. At this time, as the heat source of the heat exchanger 32 incorporated in the thermal decomposition device 24, the high temperature high pressure water passing through the high temperature high pressure water pipe line 21 of the mixed high temperature high pressure water containing gas etc. from the gas separator 20 is used. After this high-temperature high-pressure water is used as a heat source, the heater 23, the condensate preheater 39
Condensate is returned to the water tank 50 via the water.

The combustion air 1 is blown by the blower 3, heated through the air preheater 46 in the exhaust heat recovery device 27, and then supplied to the exhaust heat recovery device 27 and the thermal decomposition device 24 for thermal decomposition. The fluid fuel generated in the device 24 joins and burns. The high temperature combustion gas generated by this combustion heats the boiler 5 to generate steam. At this time, if the temperature and the pressure are set to constant values, 374.1 ° C. and 22.5 MPa or more, supercritical water, which is a vapor, has a high density, and thus has the property of water. As previously mentioned,
This high-temperature high-pressure water (supercritical water) has a high reactivity, and it has an effect of promoting decomposition even if it is difficult to decompose with ordinary steam. Here, the pressure is controlled by the water supply pump 8 to the boiler 5, and the temperature is controlled so that the temperature rises in the portion of the boiler 5 and the critical condition is satisfied. However, in practice,
It is set to about 25 MPa.

The high-temperature high-pressure water generated in the boiler 5 is supplied to the steam turbine 33 through the steam pipe 6 and drives the steam turbine 33. Due to the rotation of the steam turbine 33, the generator 34 that is interlocked with the steam turbine 33 also generates power. The steam discharged from the steam turbine 33 becomes water in the condenser 12, and makeup water is added to the condensate tank 11, so that the condenser preheater 3
It is preheated at 9 and enters the deaerator 9. In the deaerator 9, the steam turbine extraction air 10 of the steam turbine 33 is heated by the heater 23 and injected to deaerate the condensed water. The degassed water is returned to the boiler 5 by the water supply pump 8. Further, while adjusting the amount of the high temperature and high pressure water extraction gas 35 of the steam turbine 33 with the valve 4, the amount of high temperature and high pressure water required in the high temperature and high pressure water decomposition device 19 is adjusted with the valves 7 and 13, and excess high temperature and high pressure water is condensed. Condensate is returned to the condensate tank 11 by the vessel 16.

On the other hand, the high temperature and high pressure water utilization system operates as follows. A plastic composite material such as waste FRP and the like is mixed in a slurry preparation tank 17 of the plastic composite material such as waste FRP and water to form a slurry, and the slurry is supplied to a high temperature and high pressure water decomposition apparatus 19 by a slurry supply pump 41. At this time, the waste FRP
A plastic composite material slurry such as the above is supplied in a state close to a supercritical state by the heat exchanger 37. In the high-temperature high-pressure water decomposition device 19, the high-temperature high-pressure water extracted from the steam turbine 33
(High-temperature high-pressure water extraction 35 whose extraction point condition satisfies the high-temperature high-pressure water condition) is introduced to remove a plastic composite material slurry such as waste FRP that has been in a state close to a supercritical state by the heat exchanger 37. High-temperature high-pressure water decomposes into raw materials and gas.

The gas separator 20 separates the mixture of the decomposed substance and the high-temperature high-pressure water into a gas (hereinafter, referred to as gas-mixed high-temperature high-pressure water) and a solid-liquid mixture. A part of this high-temperature and high-pressure water mixed with gas is used as a heat source for raising the temperature of the plastic composite material slurry such as waste FRP to a state close to a supercritical state in the heat exchanger 37, and then heat is taken away. Condensed water is returned to the water tank 50. In addition, the high temperature and high pressure water mixed with the gas, etc., which has exited the gas separator 20, except for the portion supplied to the heat exchanger 37, passes through the high temperature and high pressure water pipeline 21, and heats the steam turbine bleed air 10 by the heater 23. After heating the condensate with the water preheater 39, the high temperature and high pressure water itself condenses and the water tank 5
Reflux to 0.

In the water tank 50, the high-temperature and high-pressure water mixed with gases of both systems joins in a condensed state, and a part thereof is recirculated to the slurry preparation tank 17 of the plastic composite material such as waste FRP as slurry preparation water. . Tank for preparing plastic composite material slurry such as waste FRP with water in the water tank 50 1
Water other than that supplied to No. 7 is sent to the pure water producing apparatus, and after the pure water treatment, is supplied to the condensate tank 11 as makeup water by the water supply pump 14 and recirculated.

When waste plastics are used as fuel, if they are burned as they are, chlorine contained in vinyl chloride, etc. generates hydrogen chloride which causes corrosion of the boiler tube, resulting in a steam temperature change.
We have to limit it to 300 degrees Celsius, 30 atmospheres,
It becomes difficult to produce high temperature and high pressure water. In this embodiment, in order to avoid this, after the waste plastic is used, the heat of the high-temperature high-pressure water is used to thermally decompose it to generate a low-temperature fluid fuel, and the dust and hydrogen chloride are removed from this fluid fuel, and the combustion is performed. Use as fuel. The high-temperature high-pressure water produced by the combustion of this fuel enters the steam turbine and drives the steam turbine. At this time, the high-temperature and high-pressure water extracted from the steam turbine is put into a high-temperature and high-pressure water treatment apparatus, and the high reactivity which is a characteristic of the high-temperature and high-pressure water is utilized to decompose the plastic composite material such as waste FRP into a raw material. High-temperature high-pressure water after decomposing plastic composite materials such as waste FRP is used as a heat source for ordinary waste plastic thermal decomposition equipment, combustion air preheating, steam turbine system feed water preheating, extraction reheating, extraction heating, make-up water and By recovering the water by preheating the waste FRP and recovering the water, the waste plastic containing the plastic composite material such as the waste FRP can be efficiently processed to obtain the raw material of the plastic composite material such as the waste FRP. And electricity can be obtained. Thus, since the waste plastic which does not require the fuel cost is burned, it can be processed at a low cost. As a result, water recovery and heat recovery can be performed to increase the heat utilization rate, make-up water is almost unnecessary, and fuel is required, so economical operation can be performed.

FIG. 2 shows a modification of the embodiment shown in FIG. 1, which is a system for decomposing the part of the thermal decomposition device 24 without thermally adding the steam system 28 to thermally decompose the plastic. According to this example, since steam is not used for pyrolysis,
It is possible to realize a system that is low-cost, environment-friendly and resource saving because it can process waste plastics as a clean fuel in a closed loop to process plastic composite materials such as waste FRP and generate electricity.

FIG. 3 is a modification of FIG. 1 and differs from the embodiment of FIG. 1 in that when producing high-temperature high-pressure water, the gas turbine is driven without directly using the combustion heat of the pyrolysis fluid fuel of waste plastic. This is the point of producing high-temperature high-pressure water using the exhaust gas after power generation. That is, the compressor 52, the gas turbine 49, and the generator motor 48 are added to the configuration shown in FIG. 1, and the combustion air 1 is preheated by the air preheater 46,
After it is compressed by the compressor 52, it is put into the combustor 38 and mixed with the pyrolytic fluid fuel of plastic to be burned.
The combustion gas after combustion is put into the gas turbine 49 to drive the generator motor 48 to generate electricity. At this time, the gas turbine 49
The exhaust gas is put into the exhaust heat recovery device 27, and high-temperature high-pressure water is generated by the boiler 5.

As described above, after the waste plastic is used, the heat of the high-temperature high-pressure water is used to pyrolyze it to generate a low-temperature fluid fuel, soot and hydrogen chloride are removed from this fluid fuel, and the combustion fuel is used. To do. Rather than directly producing high-temperature high-pressure water by the heat of combustion of this fuel, the gas turbine is first driven to generate electricity, and the high-temperature high-pressure water produced by the exhaust heat of this gas turbine is supplied to the steam turbine to generate steam. Drive the turbine. At this time, the high-temperature and high-pressure water extracted from the steam turbine is put into a high-temperature and high-pressure water treatment apparatus, and the high reactivity which is a characteristic of the high-temperature and high-pressure water is utilized to decompose the plastic composite material such as waste FRP into a raw material. At this time, the high-temperature high-pressure water after decomposing the plastic composite material such as waste FRP is used as the heat source of the thermal decomposition device, the preheating of the combustion air, the feed preheating of the steam turbine system, the extraction reheating, the extraction heating, the makeup water and the waste FRP. By recovering the water by preheating and condensing the water, the waste plastic containing the plastic composite material such as the waste FRP can be efficiently processed and not only the raw material of the plastic composite material such as the waste FRP but also water and electric power can be obtained. be able to. Thus, since the waste plastic which does not require the fuel cost is burned, the plastic composite material such as the waste FRP can be processed at low cost. As described above, it is possible to perform more efficient operation than that of the third embodiment shown in FIG. 1 even though the combustion temperature is higher than that of the third embodiment shown in FIG.

FIG. 4 shows a modification of the embodiment shown in FIG. 3, in which the thermal decomposition device 24 is a system for decomposing plastics without adding the steam system 28 to thermally decompose the plastics.
According to this example, since steam is not used for thermal decomposition, waste plastic is converted to clean fuel in a closed loop and waste F
Since a plastic composite material such as RP can be processed and power can be generated, it is possible to realize a system that is low cost, environment-friendly, and can save resources.

[0026]

As described above, according to the present invention, the high temperature, which is an effective means for generating power and decomposing composite plastics such as waste FRP, which are difficult to incinerate, by the combustion heat of the fuel produced by the thermal decomposition of waste plastics or ordinary commercial fuels. Since high-pressure water can be created and the heat and water of the high-temperature high-pressure water used for decomposition and the mixture of water and the composite plastic raw material can also be collected, it is possible to provide a highly efficient, low-cost and highly reliable waste plastic treatment and power generation system. it can.

In particular, when the waste plastic is used as a fuel, high temperature and high pressure water produced by the combustion heat of the waste plastic, which is a free fuel, can not only decompose the difficult-to-decompose composite plastic waste but also obtain electric power. There is a feature that various kinds of waste plastics can be treated organically and at low cost.

Further, since the high temperature and high pressure water decomposition and the power generation and the waste plastic and the plastic composite material such as the waste FRP are organically connected to each other in a mutually complementary form, the energy and mass of the high temperature and high pressure water after use can be recovered. It can also generate power and can be used by cleaning waste plastic.

Also, since plastic composite materials such as waste FRP can be reduced to clean raw materials by high temperature high pressure water decomposition, environmentally friendly and highly efficient plastic composite materials such as waste FRP,
It is possible to provide a waste plastic processing and power generation system.

[Brief description of drawings]

FIG. 1 is a systematic diagram of a system according to an embodiment of the present invention.

FIG. 2 is a system diagram of a system of a modified example of FIG.

FIG. 3 is a system diagram of a modified system of FIG.

FIG. 4 is a system diagram of a system of a modified example of FIG.

[Explanation of symbols]

1 ... Combustion air, 2 ... Fuel, 3 ... Blower, 4, 7, 13
... Valve, 5 ... Boiler, 6 ... Steam line, 8,14 ... Water supply pump, 9 ... Deaerator, 10 ... Steam turbine extraction, 11
... condensate tank, 12, 16 ... condenser, 15 ... pure water production apparatus, 17 ... slurry preparation tank, 18 ... plastic composite material such as waste FRP, 19 ... high temperature and high pressure water decomposition apparatus, 20
... Gas separator, 21 ... High-temperature high-pressure water conduit, 23 ... Heater,
24 ... Thermal decomposition device, 25 ... Hazardous gas / dust removal device, 2
7 ... Exhaust heat recovery device, 28 ... Steam system, 29 ... Air system,
31 ... Waste plastic, 32, 37 ... Heat exchanger, 33 ...
Steam turbine, 34 ... Generator, 35 ... High temperature and high pressure water extraction,
38 ... Combustor, 39 ... Condensate preheater, 41 ... Slurry supply pump, 42 ... Slurry, 44 ... High temperature high pressure water / decomposition mixture, 45 ... High temperature high pressure water / gas mixture, 46 ... Air preheater, 48 ... Power generation Electric motor, 49 ... Gas turbine, 50 ... Water tank, 52 ... Compressor.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI F23G 7/12 B09B 3/00 303E (72) Inventor Yukio Ishigaki 3-1-1 Sachimachi, Hitachi City, Ibaraki Hitachi Co., Ltd. (72) Shinya Hayashi, 6-38-1, Shinkawa, Mitaka City, Tokyo, within the Research Institute for Ship Technology, Ministry of Transportation (72) Kenji Yamane, 6-38-1, Shinkawa, Mitaka City, Tokyo (72) ) Inventor Kanemasa Nomaguchi 4-13-1, Higashi-cho, Hitachi-shi, Ibaraki Yamazaki factory, Hitachi Chemical Co., Ltd. (56) References JP-A-9-157663 (JP, A) JP-A-9-31473 (JP, A) JP-A-8-261424 (JP, A) JP-A-8-252824 (JP, A) JP-A-7-279622 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) C08J 11/00-11/28 B09B 3/00-5/00 C10G 1/10

Claims (8)

(57) [Claims] 1. A high-temperature high-pressure water generator for generating high-temperature high-pressure water using combustion heat of plastic, and a composite material or plastic containing plastic, part of the high-temperature high-pressure water generated by the high-temperature high-pressure water generator. A waste plastic treatment / power generation system comprising: a high-temperature high-pressure water decomposing device for thermally decomposing in 1. and a steam turbine driven by a part of the high-temperature high-pressure water generated by the high-temperature high-pressure water generating device. 2. The waste plastic treatment and power generation system according to claim 1, further comprising heat recovery means for recovering heat from the high temperature and high pressure water used in the high temperature and high pressure water decomposition apparatus. 3. A high-temperature and high-pressure water generator for generating high-temperature and high-pressure water by using combustion heat of liquid fuel obtained by decomposing plastic, and a composite material containing plastic or plastic is generated by the high-temperature and high-pressure water generator. Characterized by comprising a high-temperature high-pressure water decomposition apparatus for thermally decomposing a portion of the high-temperature high-pressure water generated, and a steam turbine driven by a part of the high-temperature high-pressure water generated by the high-temperature high-pressure water generation apparatus. Plastic processing and power generation system. 4. The waste plastic treatment / power generation system according to claim 3, further comprising heat recovery means for recovering heat from the high temperature and high pressure water used in the high temperature and high pressure water decomposition apparatus. 5. The waste plastic treatment / power generation system according to claim 4, wherein when the plastic is decomposed into a fluid fuel, it is thermally decomposed or hydrolyzed. 6. The waste plastic treatment and power generation according to claim 4, wherein the extracted air from the high-pressure stage of the steam turbine is reheated by the high-temperature high-pressure water used in the high-temperature high-pressure water separator and supplied to the low-pressure stage of the steam turbine. system. 7. A high-temperature high-pressure water generator for generating high-temperature high-pressure water by the heat of combustion of liquid fuel, and a composite material or plastic containing plastic is heated by a part of the high-temperature high-pressure water generated by the high-temperature high-pressure water generator. A high-temperature high-pressure water decomposition device that decomposes,
A steam turbine driven by a part of the high-temperature high-pressure water generated by the high-temperature high-pressure water generator is provided, and heat recovery means for recovering heat from the high-temperature high-pressure water used in the high-temperature high-pressure water decomposer is provided. Waste plastic processing and power generation system. 8. A gas turbine driven by combustion heat of liquid fuel obtained by decomposing plastic or by combustion of liquid fuel, and a high-temperature high-pressure water generator for generating high-temperature high-pressure water from exhaust gas of the gas turbine. A high-temperature high-pressure water decomposer for thermally decomposing a plastic-containing composite material or plastic with a part of the high-temperature high-pressure water generated by the high-temperature high-pressure water generator, and high-temperature high-pressure water generated by the high-temperature high-pressure water generator A waste plastic treatment and power generation system that is equipped with a steam turbine that is partly driven and that recovers heat from the high-temperature high-pressure water used in the high-temperature high-pressure water decomposition device.