JPH10219259A - Liquefying and reducing apparatus of plastic waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent corrosion of a metallic face in a thermal decomposition tank or a gas recovery duct, etc., according to a treatment of vinyl chloride as a plastic waste and exceedingly increase resistance to chemicals, resistance to corrosion, durability and reliability. SOLUTION: This liquefying and reducing apparatus 1 of plastic waste making plastic waste P thermally decompose by heating is obtained by coating liquefied glass having heat resistance on a metallic face F being or possible of brought into contact with decomposed gas G. Preferably, multilayered glass layers are provided on the metallic face F brought into contact with the decomposed gas G by repeatedly coating the liquefied glass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste plastic oil reduction apparatus for recycling waste plastic.

[0002]

2. Description of the Related Art Conventionally, waste plastic (polymer waste)
There is known an oil-reducing device that heats and thermally decomposes and then reduces it to heavy oil (corresponding to heavy oil A).

[0003] This type of oil-reducing device is made of polyethylene,
Solid waste plastics such as polysterol and vinyl chloride are melted in a melting tank heated at a relatively low temperature of around 250 ° C. (70 ° C. for vinyl chloride), and then 400 ° C.
The waste plastic dissolved in a pyrolysis tank heated to a high temperature (around 170 ° C. for vinyl chloride) is thermally decomposed, and the decomposed gas is cooled to obtain heavy oil. In addition,
If solid waste plastic is directly injected into the pyrolysis tank, not only will the waste plastic be carbonized and the reduction efficiency will be greatly reduced, but also the treatment of carbides will be difficult. Dissolves solid waste plastic.

[0004]

The gas recovery duct, the pyrolysis tank, and the like provided in this type of oil reduction apparatus are usually made of a heat-resistant metal material such as steel. Therefore, when processing waste plastics such as polyethylene and polysterol, there is no problem.However, when processing vinyl chloride, chlorine generated together with decomposition gas is generated in gas recovery ducts and pyrolysis tanks. Since corrosion and oxidation of the metal surface proceed at a considerable speed, there is a problem that the durability and reliability of the device are significantly impaired.

The present invention has been made to solve the problems existing in the prior art, and the progress of corrosion and oxidation of metal surfaces in a pyrolysis tank, a gas recovery duct, and the like accompanying the treatment of waste plastic, vinyl chloride. It is an object of the present invention to provide a waste plastic oil reduction apparatus capable of preventing the occurrence of chemicals, and significantly improving the chemical resistance, corrosion resistance, durability, and reliability.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a waste plastic oil reduction apparatus 1 that heats and thermally decomposes waste plastics P, cools generated cracked gas G, and turns it into oil. In the construction, the metal surfaces F to which the decomposed gas G contacts are particularly coated with heat-resistant liquefied glass (normal temperature glass) 25a. In this case, according to the preferred embodiment, the liquefied glass 25a, 25
, 25c... is preferably applied by multi-coating and providing a multi-layer glass layer 26.

Thus, even when a metal material such as steel is used for the pyrolysis tank 2 and the gas recovery duct 16, the metal surfaces F to which the decomposed gas G contacts are coated with the liquefied glass 25a. Even if vinyl chloride, which is waste plastic P, is treated, the generated chlorine does not come into contact with the metal material. As a result, corrosion and oxidation of the metal surfaces F in the pyrolysis tank 2 and the gas recovery duct 16 are prevented, and the chemical resistance, corrosion resistance, and durability are enhanced.

[0008]

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the configuration of the waste plastic oil reduction apparatus 1 according to the present embodiment will be described with reference to FIGS.

In the figure, reference numeral 2 denotes a thermal cracking tank which constitutes a main part of the oil reduction device 1. This pyrolysis tank 2 has a tank body 3 having a shape in which the lower side is narrower than the upper side, that is, FIGS.
The tank body 3 is formed in a semi-cylindrical shape having semicircular end surfaces 3s and 3t as shown in FIG.

At the center of the upper end of the tank body 3, a rotary screw 7 arranged in the axial direction of the tank body 3 is provided. This rotary screw 7 is rotated by a rotation drive unit 11. In addition, a supply section 8 extending outward is integrally provided above the end face 3s of the tank body 3, and a foreign substance collection section 9 extending outward is provided integrally above the end face 3t. 7
One side and the other side are accommodated in a supply unit 8 and a foreign matter collection unit 9, respectively. At this time, the lower part 7d of the rotary screw 7 is disposed so as to be immersed in the dissolved waste plastic L. Further, a hopper 12 for charging solid waste plastics P is provided above the supply unit 8, and an outlet 13 for removing collected foreign matter is provided above the foreign matter collection unit 9. Reference numeral 13c denotes an opening / closing lid for opening and closing the outlet 13.

[0012] Further, almost the entire outer surface of the tank main body 3 is surrounded by the outer plate 14, and a heat retaining portion 32 having a closed space S between the outer plate 14 and the tank main body 3 is provided. This heat retaining part 32
Is supplied from a heating device 31 to be described later. In this case, the space S between the peripheral surface 3f of the tank body 3 and the outer plate 14 may be relatively narrow because the space S may be filled with the oil C for keeping heat. The space S is filled with a heat retaining oil C, and also accommodates a curved portion of the continuous pipe 6 described later, so that an interval for accommodating the curved portion is ensured. Reference numeral 15 denotes a cover that covers the upper surface of the tank body 3, and a duct 16 that collects decomposition gas is connected to the upper center of the cover 15. This duct 16 is connected to a scrubber 52 described later.

Further, a heating mechanism 5 is attached to the tank body 3. The heating mechanism 5 has a plurality of horizontal heating tubes 4a, 4a, 4b, 4b, 4c, 4c provided inside the tank body 3.
Each of the heating tubes 4a, 4b, 4c is arranged at predetermined intervals in the vertical direction along the inner surface of the tank body 3, preferably 10 to 15 cm.
Place at intervals. In this case, each heating tube 4a, 4b, 4c
Is constituted by a plurality of straight portions formed by bending one continuous pipe 6 in a zigzag manner. That is, a plurality of straight portions in the continuous pipe 6 bent in a zigzag shape are arranged inside the tank body 3, and the curved portions are accommodated in the space S between the outer plate 14 and the tank body 3. As shown in FIG. 3, a pair of continuous pipes 6 are provided on the left and right.

On the other hand, the top openings of the heating tubes 4a, 4a arranged at the top are connected to the hot air generator 21 and the top openings of the heating tubes 4c, 4c arranged at the bottom are provided with blowers 23. Connect to chimneys 22,22. Thereby, the hot air supplied from the hot air generator 21 is supplied to the uppermost heating pipes 4a, then passes through the intermediate heating pipes 4b, and thereafter, from the lowermost heating pipes 4c to the outside. Is discharged. At this time, the temperature of the heating pipes 4c... Disposed below the heating pipes 4c.
It gradually decreases due to heat dissipation when passing through. Therefore, when the temperature of the heating pipes 4a arranged at the top reaches the temperature at which the dissolved waste plastic L is thermally decomposed, the temperature of the heating pipes 4c arranged below melts the waste plastic P. Conditions such as the diameter and length of the continuous tubes 6 (the number of the heating tubes 4a) are selected so that the temperature is reached.

Further, the outer peripheral surface of the heating pipes 4a, the inner surface of the tank body 3, the outer surface of the rotary screw 7, the metal surface of the gas recovery duct 16 for recovering the decomposed gas G, and the like, to which the decomposed gas G comes into contact. F.) are coated with a heat-resistant liquefied glass (room temperature glass) according to the present invention.

Heating tube 4a, tank body 3, rotating screw 7
Since the gas recovery duct 16 and the like are usually made of a metal material such as steel, corrosion is likely to occur. In particular, when vinyl chloride is used as waste plastic, corrosion and oxidation of the metal surfaces F proceed at a considerable rate due to the generated chlorine. Therefore, the surfaces of the heating tube 4a and the like are coated with liquefied glass 25a to avoid direct contact between the generated chlorine and the metal surfaces F, thereby improving the chemical resistance, corrosion resistance, durability, and the like.

In this case, as shown in FIG. 2, for example, a liquefied glass 25a, 25b... Is overcoated on the surface of the heating tube 4a to provide a multilayer glass layer 26.

On the other hand, reference numeral 30 denotes a heat retaining device attached to the thermal decomposition tank 2, and the heat retaining device 30 includes a heating device 31.
The heating device 31 includes a heating unit 33, and a discharge unit of the heating unit 33 is connected to one upper side of the heat retaining unit 32 via a pipe 35 having a valve 34, as shown in FIGS. The suction section of the heating section 33 is connected to the other upper side of the heat retaining section 32 via a pipe 37 having a valve 36. Thereby, after the heat retaining oil C is heated by the heating unit 33, the oil C is supplied to the space S between the outer plate 14 and the tank body 3 constituting the heat retaining unit 32 via the pipe 35,
The oil C for keeping heat in the space S is supplied to the heating unit 3 via the pipe 37.
The heating circulation circuit returned to 3 is constituted. Reference numeral 38 denotes an oil tank connected to the heating unit 33 via a valve 39; 40, a control unit for controlling the operation of the heating unit 33 and various controls such as heating temperature; and 41, a function for liquefying vaporized oil for heat retention. Extension part.

FIG. 4 shows an oil reduction apparatus 1 having a pyrolysis tank 2.
1 shows the entire configuration. In the figure, 51 is a crusher for crushing large waste plastics into small pieces, 52 is a scrubber for neutralizing chlorine gas, 53 is a PH adjustment tank attached to the scrubber, and 54 is a condenser for liquefying decomposed gas. And 55, a cooler (cooling tower) for cooling the condenser 54, 56, a pump, 57, an oil / water separation tank for separating the obtained heavy oil and water, 58, a filter, and 59, a heavy oil storage tank.

Next, the overall operation of the liquefaction and reduction apparatus 1 including the function of the pyrolysis tank 2 constituting a main part of the present embodiment will be described with reference to the drawings.

First, hot air is supplied to the heating pipes 4a, 4a arranged at the top by the hot air generator 21. This allows
400 ° C for the heating tubes 4a, 4a (170 ° C for vinyl chloride)
Heated back and forth. Also, the heating tube 4c arranged at the lowermost part,
4c is heated to around 250 ° C (70 ° C for vinyl chloride). The diameter and length of the continuous tubes 6 (the number of the heating tubes 4a) are selected so as to obtain such a temperature. Then, the hot air is discharged from the chimneys 22 and 22 to the outside. At this time, air is also sucked in by the blower 23.

On the other hand, solid waste plastics (polyethylene, polysterol, vinyl chloride, etc.)
It is thrown into 2. At this time, the large waste plastic is crushed into small pieces by the crusher 51. In addition, the rotation drive unit 1
1 is operated to rotate the rotary screw 7. Thereby, the solid waste plastic P put into the hopper 12
Are transferred by the rotary screw 7 and supplied into the tank body 2. By controlling the rotation speed of the rotary screw 7 arbitrarily, the supply amount of the waste plastics P to the tank body 2 can be adjusted.

The waste plastic P supplied to the inside of the tank body 2 falls to the bottom of the tank body 2 and is heated by the relatively low-temperature heating pipes 4c, 4c arranged at the lowermost part of the tank body 2. Dissolve. The dissolved waste plastic L is stored in the tank main body 2, and the liquid level of the dissolved waste plastic L rises with the increase. Then, when the raised liquid level reaches the uppermost heating pipes 4a, 4a, it is heated by the high-temperature heating pipes 4b, 4a, and the waste plastic L is vaporized by being thermally decomposed. In addition, waste plastic L
Foreign matter such as carbides floating on the upper surface of the waste plastic L is collected by the foreign matter recovery unit 9 by the rotating screw 7, and the upper surface of the waste plastic L is agitated and purified, thereby increasing the generation efficiency of the decomposition gas.

On the other hand, the vaporized decomposition gas is supplied to the scrubber 52 through the duct 16, and the mixed chlorine gas is neutralized. Further, the cracked gas is supplied from the scrubber 52 to the condenser 54 and cooled to be liquefied into heavy oil (equivalent to heavy oil A). The condenser 54 is constantly cooled by the cooling liquid sent from the cooler 55. Then, the obtained heavy oil is supplied to the oil / water separation tank 57. In the oil / water separation tank 57, water and heavy oil are separated, and the heavy oil is filtered by the filter 5.
After the impurities are removed by the hot air generator 8, the hot air generator 2 is supplied to and stored in the storage tank 59.
1 and used as fuel for the hot air generator 21.

During the period when the operation of the liquefaction reduction apparatus 1 is stopped at night or the like, the temperature of the thermal decomposition tank 2 is maintained by the heat retaining apparatus 30. In this case, the heating oil C is heated by the heating unit 33 to a temperature of 70 to 400 ° C.
5, the oil C is supplied to the space S between the outer plate 14 and the tank main body 3 that constitute the heat retaining unit 32, and the heat retaining oil C in the space S is returned to the heating unit 33 via the pipe 37. Thereby, the waste plastic L remaining in the tank main body 3 is kept warm, and the start-up time at the time of restarting the operation can be greatly reduced.

The embodiment has been described in detail above.
The present invention is not limited to such an embodiment, and can be arbitrarily changed in the detailed configuration, shape, material, quantity, method, and the like without departing from the gist of the present invention. For example, the metal surface touched by the decomposition gas is not limited to the example, but is applied to any metal surface touched by the decomposition gas or any metal surface that may touch.

[0027]

As described above, according to the present invention, in a waste plastic oil reduction apparatus that heats and thermally decomposes waste plastic, and cools and decomposes the generated decomposition gas, the metal surface contacted with the decomposition gas is reduced. Because it is coated with heat-resistant liquefied glass, it prevents corrosion and oxidation of metal surfaces in pyrolysis tanks and gas recovery ducts associated with the treatment of waste plastic, vinyl chloride, and has chemical and corrosion resistance. In addition, a remarkable effect that the durability and the reliability can be remarkably improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional side view of a thermal decomposition tank provided in an oil reduction device according to the present embodiment,

FIG. 2 is a partial cross-sectional view of a heating tube in the pyrolysis tank,

FIG. 3 is a sectional front view of the pyrolysis tank,

FIG. 4 is a block diagram showing an overall configuration of the oil-reducing device.

FIG. 5 is a block diagram of a heat retaining device provided in the oil-reducing device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oil reduction apparatus 2 Thermal decomposition tank 3 Tank main body P ... Waste plastic G Decomposed gas F ... Surface which decomposed gas touches 25a ... Liquefied glass 26 Glass layer

Claims (2)

[Claims] 1. A waste plastic is heated and thermally decomposed,
An apparatus for liquefying waste plastics, which cools and decomposes the generated decomposition gas into oil, characterized in that the metal surface contacted with the decomposition gas is coated with liquefied glass (normal temperature glass) having heat resistance. Oil reduction device for waste plastic. 2. The waste plastic oil reduction apparatus according to claim 1, wherein the liquefied glass is overcoated on a metal surface contacted with the decomposition gas, and is coated by providing a multilayer glass layer. .