JPH06206058A - Apparatus and method for melting and decomposing waste plastics - Google Patents

Abstract

PURPOSE:To obtain a waste plastics melting and decomposing apparatus efficiently operated from the aspect of energy by providing a reaction vessel externally provided with a jacket, a heat exchanger heating HCl-containing circulating gas and a heating furnace heating the hot medium oil to the jacket or forming hot air. CONSTITUTION:The waste plastics melting and decomposing apparatus is equipped with a reaction vessel constituted so that a vessel main body 1 is externally provided with a jacket 16 and a HCl-containing circulating gas outlet 9 is provided to the top wall 5 of the vessel main body and a gas inlet 10 is provided to the central lower part of the vessel, a heat exchanger 15 heating the HCl-containing circulating gas emitted from the reaction vessel and a heating furnace 2 heating the hot medium oil sent into the jacket 16 or forming hot air. By this constitution, the reaction vessel is heated from the outside by sending the hot medium oil or hot air into the jacket 16 provided to the outside of the vessel main body 1 and the HCl-containing circulating gas emitted from the reaction vessel is subjected to heat exchange by the heating furnace 2 and the heat exchanger 15 to be returned to the reaction vessel to heat the reaction vessel from the inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses, for example, a volume reduction processing apparatus for composite waste plastics made of thermoplastics or thermosetting plastics, a volume reduction processing apparatus for thermoplastics, and HCl gas for thermosetting plastics. The present invention relates to a melting and decomposing apparatus and a melting and decomposing method for waste plastic that can be applied to a system such as a decomposing apparatus.

[0002]

2. Description of the Related Art As a heating method for melting or decomposing waste plastic, a method of heating a kettle with combustion hot air formed by combustion of fuel is often adopted. On the other hand, when a waste plastic mixed with various kinds of plastics is heated, HCl gas is generated when polyvinyl chloride, polyvinylidene chloride and the like contained therein are decomposed, and this corrodes the inner surface of the heating pot. As a countermeasure against this, it is conceivable to line the inner surface of the kettle with a food resistant material such as glass lining. In that case, the lining material may be damaged unless the kettle is heated uniformly.

Further, when a composite plastic containing polyvinyl chloride or the like is heated to 300 ° C. or higher, toxic substances such as dioxins may be generated, so the heating temperature is 300 ° C.
The following needs to be controlled.

In the above heating method using hot air for combustion, the fuel is burned by the burner and the hot air produced is blown directly to the kettle to heat the kettle. There is a possibility that there will be a temperature difference at each location inside the kettle.

In view of the above points, an object of the present invention is to provide an apparatus and method for melting and decomposing waste plastics which can be efficiently implemented in terms of energy.

[0006]

The present invention has been devised in order to achieve the above-mentioned object, and the reaction kettle is surrounded by a jacket, and heated heating medium oil or hot air is sent thereto. By heating the kettle uniformly from the outer circumference, circulating the HCl-containing gas in the reaction kettle inside, and heating this circulating gas with the exhaust gas of the heating furnace for heating the heat carrier oil or forming hot air, and returning it to the reaction kettle. It is an apparatus and a method for melting and decomposing waste heat-recovery type waste plastic, which also uses a method of heating a reaction kettle from the inside. That is, in the melting and decomposing apparatus for waste plastic according to the present invention, the kettle body is covered with a jacket, and HCl is provided on the top of the kettle.
A reactor equipped with an outlet for the contained circulating gas and an inlet for the same gas in the lower center of the reactor, a heat exchanger for heating the HCl-containing circulating gas discharged from the reactor, and a jacket. And a heating furnace that heats the heat carrier oil to be fed or forms hot air.

Further, in the method for melting and decomposing waste plastics according to the present invention, the HCl-containing circulating gas discharged from the reaction vessel is heat-exchanged with the exhaust gas of the heating furnace for heating the heating medium oil or for forming the hot air and returned to the reaction vessel. Is characterized in that the reaction kettle is heated from the inside.

Another method of melting and decomposing waste plastic according to the present invention is to heat the reaction vessel from the outside by sending heat medium oil or hot air to a jacket externally mounted on the vessel body, and to discharge the reaction vessel from the reaction vessel. The reaction vessel is heated from the inside by exchanging the HCl-containing circulating gas with the exhaust gas of the heating furnace for heating the heat carrier oil or forming the hot air and returning it to the reaction vessel.

[0009]

The present invention will now be described in detail with reference to the illustrated embodiments.

Embodiment 1 In FIG. 1 attached, a pot main body (1) is in the shape of a vertical cylinder having a cone-shaped bottom, and an inner surface is lined with a food-resistant material such as glass lining. The kettle body (1) is provided with a jacket (16), and the heating medium (2) sends heat medium oil to the jacket to heat the kettle.

Inside the hook body (1), a lattice plate (3) is arranged horizontally at the bottom of a vertical cylinder. Top wall of the hook body (1)
At the center of (5), a lattice plate support cylinder (4) is provided in a hanging shape, and the lattice plate (3) is supported at the lower end of the cylinder (4).

On one side of the top wall (5) of the hook body (1), a connecting pipe (8) for guiding the waste plastic coming from the hopper (6) through the screw feeder (7) to the hook body (1). Are connected.

A circulating gas outlet (9) is provided on the other side of the top wall (5) of the shuttle body (1). Also, a lattice plate support tube
A number of circulating gas inlets (10) are formed in the lower half of (4). Inside the lattice plate support cylinder (4), an internal pipe (11) for guiding the circulating gas is arranged at the lower end thereof.

From the circulating gas outlet (9) to the inner pipe (11),
A circulation path (12) is provided for returning the circulating gas discharged from the pot to the pot again. The circulation path (12) is provided with a blower (13), a flow control valve (14) and a gas-gas heat exchanger (15). Exhaust gas from the heating furnace (2) is guided to the gas-gas heat exchanger (15) by the exhaust gas pipe (22) and heats the circulating gas from the reaction vessel.

The top wall (5) of the pot main body (1) is provided with a pyrolysis gas discharge port (18), and the bottom is provided with a residue removal port (19). The residue outlet (19) is opened / closed by an opening / closing valve (20).

In the reaction kettle of the above construction, the heating of the reaction kettle is carried out by sending the heat carrier oil from the heating furnace (2) to the jacket (16) of the kettle body (1). The heated heat transfer oil is sent to the jacket (16) of the kettle body (1) from the heating furnace (2) at about 340 ° C by the supply pump (17), and the jacket (16)
It is returned to the heating furnace (2) at about 320 ° C. In this way, the reaction kettle is externally heated.

The waste plastic crushed to an appropriate size (30 mm or less) is put into the hopper (6) and sent to the connecting pipe (8) by the screw feeder (7), through which the pot main body (1) is fed. Is supplied to.

The gas inside the reaction vessel is supplied to the flow control valve (14) and the gas-gas heat exchanger by the blower (13) of the circulation path (12).
It goes through (15) to the internal pipe (11), and the lattice plate support cylinder
The waste plastic pieces are circulated from the multiple outlets (10) of (4) to the inside of the reaction kettle to promote thermal decomposition. Exhaust gas of about 400 ° C. is introduced from the heating furnace (2) to the gas-gas heat exchanger (15) and the circulating gas from the reaction vessel is heated to about 300 ° C.

The inlet temperature of the circulating gas to the reaction vessel is detected by the temperature detector (21), and the signal is sent to the flow control valve (14), and the inlet temperature of the circulating gas rises above a certain level by adjusting this valve. The amount of circulating gas in the gas-gas heat exchanger (15) is controlled so as not to do so. Thus, the circulating gas also heats the pot from the inside.

In the inside of the pot main body (1), the waste plastic pieces on the lattice plate (3) are exposed to the circulating gas and are reduced in volume by promoting the thermal decomposition reaction. Due to the progress of the thermal decomposition reaction of the waste plastic pieces, the residue that has become smaller than the hole diameter of the lattice plate (3) passes through the holes and is discharged to the outside from the bottom outlet (19).

The substance gasified by the thermal decomposition reaction is discharged at the outlet (1
It is taken out of the kettle from 8), cooled by a cooler, collected as a liquid substance, and used for recycling fuel and the like.

Embodiment 2 In FIG. 2 attached, a hot air generator (23) communicates with one side of the bottom portion of the jacket (16) of the kettle body (1) through a passage (24), and the reaction kettle is a hot air generator. It is heated by hot air coming from (23). Exhaust gas is introduced from the jacket (16) to the gas-gas heat exchanger (15) by the exhaust gas pipe (25) to heat the circulating gas from the reaction vessel.

The other structure of FIG. 2 is the same as that of FIG.

This modification is preferably applied when it is not necessary to uniformly heat the outer circumference of the reaction kettle.

[0025]

EFFECTS OF THE INVENTION Since the present invention is constituted as described above, the melting and decomposition of waste plastics can be carried out energetically efficiently and, for example, a composite waste plastic containing chlorine-containing plastics such as polyvinyl chloride and polyvinylidene chloride. Can be melted and decomposed efficiently.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a reaction kettle of Example 1.

2 is a vertical sectional view showing a reaction kettle of Example 2. FIG.

[Explanation of symbols]

 (1)… Boiler body (2)… Heating furnace (3)… Lattice plate (4)… Lattice plate support cylinder (5)… Top wall (6)… Hopper (7)… Screw feeder (8)… Communication pipe ( 9)… Outlet (10)… Inlet (11)… Inner pipe (12)… Circulation path (13)… Circulation blower (14)… Open / close valve (15)… Gas-gas heat exchanger (16)… Jacket (17) )… Supply pump (18)… Pyrolysis gas outlet (19)… Residue material outlet (20)… Open / close valve (21)… Temperature detector (22)… Exhaust gas line (23)… Hot air generator (24) ) ... Passage (25) ... Exhaust gas pipeline

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location F23G 7/12 ZAB Z 7815-3K (72) Inventor Katsuya Asao 1 38 Osaka Prefectural Institute of Advanced Industrial Science and Technology (72) Inventor Tsutomu Nakatsuka 1-4-6 Sakurajima, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Engineering Co., Ltd. (72) Inventor Rikimaru ▲ Koma ▼ Konohana-ku, Osaka City 1-6-6 Sakurajima Hitachi Shipbuilding Engineering Co., Ltd. (72) Takashi Katayama 1-4-6 Sakurajima Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Engineering Co., Ltd.

Claims (3)

[Claims] 1. A reaction vessel equipped with a jacket for the vessel main body, an outlet for HCl-containing circulating gas at the top of the vessel, and an inlet for the gas at the lower center of the vessel, and a reactor vessel 2. A melting and decomposing apparatus for waste plastic, comprising: a heat exchanger for heating the HCl-containing circulating gas; and a heating furnace for heating the heat carrier oil fed to the jacket or for forming hot air. 2. The reaction kettle is heated from the inside by exchanging heat of the HCl-containing circulating gas discharged from the reaction kettle with the exhaust gas of a heating furnace for heating the heating medium oil or forming hot air and returning it to the reaction kettle. Method for melting and decomposing waste plastics. 3. The reaction vessel is heated from the outside by sending the heating medium oil or hot air to a jacket externally mounted on the vessel body, and the HCl-containing circulating gas discharged from the reaction vessel is used for heating the heating medium oil or for forming hot air. The method for melting and decomposing waste plastic, characterized in that the reaction kettle is heated from the inside by exchanging heat with the exhaust gas of the heating furnace and returned to the reaction kettle.