JPH08334221A - Waste resin disposal apparatus - Google Patents

Abstract

PURPOSE: To carry out recovery of heat very easily by separating waste resins into decomposed gases and a resin melt liquid by a heat decomposition device to introduce them to a burner of an incineration/heat recovery device separately to recover heat by burning. CONSTITUTION: Waste resin P selected by removing polychloride vinyl or the like unsuitable for conversion into oil previously is fed into a hopper 1 and when it is supplied to a top part of a heat decomposition kiln 5 by a screw feeder, the waste resin P is heated by a combustion gas from an oil burner 7 of a heating furnace 6 to be melted and decomposed thermally. A resin melt liquid thus obtained is stirred up by an agitation blade 4 of an agitator 3. Decomposed gases generated by the thermal decomposition and an oil vapor are reformed to a light component by a plurality of catalytic layers 11 armored on a flue 12 of the combustion gas from the heating furnace 6. Then, the decomposed gases and the oil vapor are sent to a burner for incineration of a boiler via a knock out pot 14, a backfire preventing safety device 18 and a reheater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus for waste plastics, which heats and melts waste plastics such as wastes of thermoplastics to produce pyrolytic oil, and more specifically, decomposed gas produced by the thermal decomposition. And a waste plastic processing apparatus for incinerating a melt and recovering its energy.

[0002]

2. Description of the Related Art Conventionally, as a method for treating waste plastics such as used thermoplastics, a method of incinerating it as it is and recovering its thermal energy or a method of landfilling has been used. . However, due to the growing needs for resource recycling and the difficulty of securing landfill sites, the method of treating waste plastic tends to separate and recover it, and thermal recycling is the most common. One example of this is the technology for oiling waste plastics, which is already nearing the stage of practical application. However, this has the drawback of being poorly economical.

Generally, a method of incinerating waste plastic is performed by kiln incineration, fluidized bed incineration, etc.
All of the incinerators are in a situation where it is difficult to put them into practical use due to burnout of the furnace due to high temperature incineration and clinker trouble. Further, in the case of incineration of waste plastics, if chlorine-containing polymers such as polyvinyl chloride are contained in the waste plastics, secondary pollution due to HCl or dioxin is likely to occur. Moreover, since waste plastic is solid and has a low density, it is extremely difficult to handle as a fuel.

[0004]

The present invention has been made with the intention of solving the above-mentioned problems of the prior art.

According to the first aspect of the present invention, there is provided a thermal decomposition device for thermally decomposing waste plastic from which oil-incompatible substances have been removed beforehand into an oil,
A waste plastic processing device comprising an incineration / heat recovery device for recovering heat generated by incinerating a decomposition gas and a melt generated by thermal decomposition of waste plastic.

This apparatus is applied to a method for treating a fractional waste plastic from which a chlorine-based polymer such as polyvinyl chloride or an oily unsuitable substance such as polyethylene phthalate has been removed in advance. FIG. 1 shows a processing method flow sheet performed by using the waste plastic processing apparatus according to claim 1.
Show as the law.

According to the second aspect of the present invention, a thermal decomposition device for thermally decomposing waste plastic into oil, a dechlorination device for removing chlorine components in decomposition gas produced by thermal decomposition of waste plastic, and dechlorinated decomposition It is a waste plastic processing device comprising an incineration / heat recovery device for recovering heat generated by incinerating a melt of gas and waste plastic.

This apparatus is preferably applied to a method for treating unfractionated waste plastics that may contain an unsuitable oil product such as polyvinyl chloride, or an unsuitable oil product such as polyvinyl chloride itself. It A processing method flow sheet performed by using the waste plastic processing apparatus according to claim 2 is shown as a method II in FIG.

[0009]

In the waste plastic processing apparatus according to the present invention, the waste plastic is first separated into the gas, that is, the decomposition gas and the liquid, that is, the plastic melt, by the thermal decomposition apparatus, and then these are separately separated by the incineration / heat recovery apparatus. Since it is introduced into a burner and incinerated to recover heat, it is possible to recover heat very easily as compared with the conventional method in which solid plastic is directly treated.

[0010]

Embodiments of the present invention will be specifically described with reference to the drawings.

Example 1 This example illustrates a waste plastic processing apparatus according to claim 1.

First, the pyrolysis oilification device (33) in the waste plastic processing device will be described.

In FIG. 2 and FIG. 3, a separated waste plastic in which oil-incompatible substances (chlorine polymers such as polyvinyl chloride, polyethylene phthalate, etc.) have been removed in advance.
(P) is put into the hopper (1), enters the screw feeder (2) from here, and the thermal decomposition pot is fed by the feeder (2).
Supplied on top of (5).

The waste plastic (P) supplied into the pyrolysis kettle (5) is a heating furnace that covers the bottom and the periphery of the pyrolysis kettle (5).
It is heated by the combustion gas from the oil burner (7) of (6) and 2
It is melted and pyrolyzed at a temperature of 50 to 450 ° C. The plastic melt is well stirred by the stirring blade (4) of the stirrer (3).

Decomposition gas and oil vapor generated by the thermal decomposition of waste plastic are converted into light components by a plurality of catalyst layers (11) provided on the flue (12) of the combustion gas discharged from the heating furnace (6). Be quality. The decomposed gas and oil vapor are then passed through a knockout pot (14), a flashback prevention safety device (18) and a reheating device (19), and then an incinerator burner (22) as an incineration / heat recovery device described later. Sent to 21). Reheating device
(19) is to reheat cracked gas and oil vapor to a temperature of preferably 300 to 450 ° C so that they are not condensed in the conduit. A tube heating device (20) such as a heater trace is externally mounted on this conduit so that the above-mentioned condensation does not cause blockage in the tube.

On the other hand, the melt produced by heating the waste plastic is guided to the melt pot (8) from the bottom of the pyrolysis kettle (5) through the hanging passage (30) penetrating the heating furnace (6). From here, via the melt transport pump (15) and strainer (16), it is also transported to the burner (21) for incineration of the boiler (22) under high pressure.

Condensed oil accumulated in the knockout pot (14) collects pressure equalizer (9) and liquid level detector (differential pressure oscillator) (10).
And is sent to the melt pot (8).

Fuel is supplied to the oil burner (7) of the heating furnace (6) by a fuel pump (17). The combustion gas emitted from the heating furnace (6) heats the plurality of catalyst layers (11) while passing through the flue (12), and is then discharged from the chimney (13) to the outside of the system.

Next, a boiler as an incineration / heat recovery device
(22) will be described.

In the burner (21) for incineration of the boiler (22), the reheating gas of the decomposition gas and oil vapor and the plastic melt are individually sprayed directly into the incinerator (31) of the boiler (22) by the burner nozzle. And is completely incinerated by heated air provided as a sufficient amount as combustion air. The heat energy generated by this incineration is recovered by the water absorption pump (26) into water that is passed through the steam generator (23) including the tube group of the boiler (22) and air that is passed through the air heater (24). The generated steam is partially stored in the steam drum (32) on the top of the boiler (22).

As described above, by spraying the plastic melt into the incinerator (31), stable combustion can be continuously performed, the in-reactor combustion is a space combustion, and the periphery of the furnace is heated. Since it is composed of a collection pipe group, there is no burning of the furnace or clinker trouble.

The incineration gas discharged from the incinerator (31) of the boiler (22) is a dust removing device (27) such as an electric dust collector or a bag filter.
And it is discharged from the chimney (29) to the outside of the system through the exhaust gas induction fan (28).

Inorganic substances (Al, S
(i, Mg, Ca, etc.) is partially incinerated as bottom ash (31)
From the bottom part of the ash to the bottom ash discharger (25), it is taken out of the system by this, and a part is removed as fly ash dust ash.
It is removed from the system by (25).

Regarding the connection relationship between FIG. 2 and FIG. 3, connection between FIG. 2 (A) and FIG. 3 (A), and connection between FIG. 2 (B) and FIG. 3 (B), respectively. ing.

Example 2 In this example, the anti-reverse safety device (18) and the reheating device (1
A dechlorination device is installed in the pipe between 9), and unfractionated waste plastics that may contain unsuitable products such as polyvinyl chloride, or unsuitable oil products such as polyvinyl chloride itself are the target of treatment. is there.

When the plastic to be treated contains a chlorine-based polymer such as polyvinyl chloride, the thermal decomposition pot (5)
Hazardous gas such as HCl generated inside is discharged from the thermal decomposition vessel (5) together with the decomposition gas, which is absorbed and removed by the HCl absorbent (CaO powder or the like) in the dechlorination unit.

The other structure is substantially the same as that of the first embodiment.

[0028]

In the waste plastic processing apparatus according to the present invention, the waste plastic is first separated into the gas, that is, the decomposition gas and the liquid, that is, the plastic melt by the thermal decomposition apparatus, and then these are separately incinerated and the heat is recovered. Since it is guided to the burner of the apparatus to be incinerated for heat recovery, heat recovery can be performed extremely easily as compared with the conventional method of handling solid plastic as it is.

In the incinerator / heat recovery device, the combustion in the incinerator is a space combustion, and the periphery of the furnace is constituted by the heat recovery tube group, so that the burnout of the furnace and the occurrence of clinker trouble can be prevented.

The thermally decomposed waste plastics are all sent to the incineration / heat recovery device as decomposition gas and plastic melt, so that there is no heat and substance loss and efficiency is very good.

Since the decomposed gas and the melt are sprayed and incinerated in one incinerator of the incineration / heat recovery device, generation of black smoke can be prevented.

[Brief description of drawings]

FIG. 1 is a flow sheet showing a processing method performed using a waste plastic processing apparatus according to the present invention.

FIG. 2 is a vertical sectional view showing a thermal decomposition apparatus in the waste plastic processing apparatus according to claim 1.

FIG. 3 is a vertical sectional view showing an incineration / heat recovery device in the waste plastic processing device according to claim 1.

[Explanation of symbols]

 1: Hopper 2: Screw feeder 3: Stirrer 4: Stirring blade 5: Thermal decomposition kettle 6: Heating furnace 7: Oil burner 8: Melt pot 9: Pressure equalizer 10: Liquid level detector (differential pressure oscillator) 11 : Catalyst layer 12: Flue 13: Chimney 14: Knockdown pot 15: Melt transport pump 16: Strainer 17: Fuel pump 18: Flashback prevention safety device 19: Reheating device 20: Pipe heating device 21: Burner for incineration 22: Boiler 23: Steam generator 24: Air heater 25: Bottom ash ejector 26: Water supply pump 27: Dust remover 28: Exhaust gas induction fan 29: Chimney

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F23G 5/46 ZAB 9547-4H C10G 1/10 ZAB 7/06 ZAB B09B 3/00 ZAB // C10G 1/10 ZAB 302A (72) Yusuke Okada 5-3-28 Nishikujo, Konohana-ku, Osaka City Hitachi Shipbuilding Co., Ltd. (72) Inventor Michio Ito 5-3-28 Nishikujo, Konohana-ku, Osaka Hitachi Shipbuilding Within the corporation

Claims (2)

[Claims] 1. A thermal decomposition apparatus for thermally decomposing waste plastic from which oil-incompatible substances have been removed in advance, and a heat generated by incinerating a decomposition gas and a melt generated by thermal decomposition of the waste plastic. Waste plastic processing equipment consisting of incineration and heat recovery equipment. 2. A thermal decomposition device for thermally decomposing waste plastic into oil, a dechlorination device for removing chlorine components in decomposition gas generated by thermal decomposition of waste plastic, and incineration of dechlorinated decomposition gas and plastic melt. Waste plastic processing equipment consisting of incineration and heat recovery equipment that recovers the heat generated.