JP3938962B2 - Waste plastic oil reduction equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waste plastic oil reduction apparatus for recycling waste plastic.
[0002]
[Prior art]
Conventionally, an oil reduction apparatus that heats and decomposes waste plastic (polymer waste) to heavy oil (equivalent to heavy oil A) is known.
[0003]
This type of oil reduction apparatus dissolves solid waste plastics such as polyethylene, polyesterol, and vinyl chloride in a dissolution tank that is heated at a relatively low temperature of about 250 ° C. (vinyl chloride is about 70 ° C.). The waste plastic dissolved in a pyrolysis tank heated to a high temperature around 400 ° C. (vinyl chloride is 170 ° C.) is pyrolyzed, and the vaporized decomposition gas is cooled to obtain heavy oil. In addition, when solid waste plastic is directly put into the pyrolysis tank, the waste plastic is carbonized, not only the reduction efficiency is greatly reduced, but also the treatment of carbide becomes difficult, so by providing a dissolution tank, First, solid waste plastic is dissolved.
[0004]
[Problems to be solved by the invention]
By the way, this type of oil reduction apparatus often has a state in which the dissolved waste plastic remains in the thermal decomposition tank when the apparatus is stopped after one day of operation. In this case, even if the device is restarted on the next day, the contact area of the heating function part with respect to the waste plastic in the pyrolysis tank is partial, and the melting proceeds due to the heat transmitted to the waste plastic, etc. Due to the reason, it takes about half a day for the start-up time, and there is a problem that it is extremely disadvantageous in terms of productivity and economy.
[0005]
The present invention solves such a problem existing in the prior art, and even when waste plastic remains in the pyrolysis tank, the start-up time for restarting is greatly reduced. An object of the present invention is to provide a waste plastic oil-reduction apparatus capable of dramatically improving productivity and economy.
[0006]
[Means for Solving the Problems and Embodiments]
In the present invention, when the waste plastic oil-reduction apparatus 1 including the thermal decomposition tank 2 that heats and decomposes the waste plastics P ... is configured, in particular, the waste plastic P ... The tank body 3 having a narrow width, and a plurality of horizontal heating tubes 8a, 8b,..., 8c arranged at predetermined intervals in the vertical direction along the inner surface of the tank body 3 in the tank body 3. ... and a thermal decomposition tank 2 having a heating mechanism 9 in which the temperature of the heating pipes 8c arranged below is set lower than the temperature of the heating pipes 8a arranged above, and heat when not in operation It is characterized by comprising a heat retaining device 4 for heating the tank body 3 in the decomposition tank 2 to a preset heat retaining temperature Th.
[0007]
In this case, according to a preferred embodiment, the heat retaining device 4 surrounds almost the entire outer surface 3o of the tank body 3 with the outer plate 5, and the heat retaining device provided with a sealed space S between the outer plate 5 and the tank body 3. It can comprise by the heating apparatus 7 which circulates the part 6 and the oil C for the heat insulation heated to this heat insulation part 6. FIG. The tank body 3 can be formed in a semicylindrical shape having semicircular end faces 3s and 3t. The plurality of heating tubes 8a, 8b, and 8c are constituted by a plurality of straight portions formed by bending one continuous tube 10 in a zigzag shape, and supply hot air to the heating tube 8a disposed at the top. At the same time, the air can be exhausted from the heating tube 8c disposed at the bottom. It is desirable that a pair of the continuous pipes 10 be disposed on the left and right.
[0008]
Thereby, the tank main body 3 is heated by the heat retention apparatus 4 to the heat retention temperature Th set beforehand at the time of non-operation. That is, the heat retaining oil C heated by the heating device 7 is supplied to the space S of the heat retaining unit 6, while the heat retaining oil C that has been heat-exchanged in the space S is returned to the heating device 7 and heated again. A heating circulation circuit is configured. As a result, the waste plastic remaining in the tank body 3 is maintained at the heat retention temperature Th, and the start-up time is greatly shortened when restarting.
[0009]
【Example】
Next, preferred embodiments according to the present invention will be given and described in detail with reference to the drawings.
[0010]
First, the structure of the waste plastic oil-reduction apparatus 1 according to the present embodiment will be described with reference to FIGS.
[0011]
In the figure, 2 is a thermal decomposition tank provided in the oil reduction apparatus 1. The pyrolysis tank 2 is formed in a tank body 3 having a shape in which the lower width is narrower with respect to the upper side, that is, a semi-cylindrical shape having semicircular end faces 3s and 3t as shown in FIGS. The tank body 3 is provided.
[0012]
A rotary screw 11 arranged in the axial direction of the tank body 3 is provided at the center of the upper end of the tank body 3. The rotary screw 11 is rotated by a rotation drive unit 11x. Further, the supply portion 12 extending outward is integrally provided on the upper portion of the end surface 3s in the tank body 3, and the foreign matter collecting portion 13 extending outward is integrally provided on the upper portion of the end surface 3t. One side and the other side of 11 are accommodated in the supply unit 12 and the foreign material recovery unit 13, respectively. At this time, the lower part 11 d of the rotary screw 11 is arranged so as to be immersed in the molten waste plastic L. Further, a hopper 14 for charging solid waste plastic P is provided at the upper part of the supply unit 12, and an outlet 15 for taking out the collected foreign matter is provided at the upper part of the foreign matter collection unit 13. Reference numeral 15c denotes an open / close lid that opens and closes the outlet 15.
[0013]
Further, the tank body 3 is provided with a heat retaining unit 6 constituting the heat retaining device 4. The heat retaining unit 6 surrounds almost the entire outer surface of the tank body 3 with the outer plate 5, and provides a sealed space S between the outer plate 5 and the tank body 3. The heat retaining unit 6 is supplied with heat retaining oil C from a heating device 7 described later. In this case, the space S between the peripheral surface 3f of the tank body 3 and the outer plate 5 only needs to be filled with the heat retaining oil C, and therefore may be relatively narrow, but between the end surfaces 3s, 3t of the tank body 3 and the outer plate 5. In addition to filling the heat retaining oil C, the space S accommodates the curved portions of the continuous pipes 10 to be described later, so that an interval that can accommodate the curved portions is secured. Therefore, with such a structure of the heat retaining portion 6, it is possible to perform effective heat retention during non-operation, and to enhance the heat insulation of the tank body 3 during operation.
[0014]
On the other hand, 16 is a cover that covers the upper surface of the tank body 3, and a duct 17 that collects cracked gas is connected to the upper center of the cover 16. This duct 17 is connected to a scrubber 52 described later.
[0015]
Furthermore, the tank body 3 is provided with a heating mechanism 9. The heating mechanism 9 has a plurality of horizontal heating pipes 8 a, 8 a, 8 b, 8 b, 8 c, 8 c provided inside the tank body 3. Each heating tube 8a, 8b, 8c is arranged at predetermined intervals in the vertical direction along the inner surface of the tank body 3, and preferably at intervals of 10 to 15 cm. In this case, each heating pipe 8a, 8b, 8c is constituted by a plurality of straight portions formed by bending one continuous pipe 10 in a zigzag shape. That is, a plurality of straight portions in the continuous pipe 10 bent in a zigzag shape are arranged inside the tank body 3, and the curved portion is accommodated in the space S between the outer plate 5 and the tank body 3 described above. As shown in FIG. 1, a pair of continuous pipes 10 are arranged on the left and right.
[0016]
Moreover, while the front-end | tip opening of heating pipe 8a, 8a distribute | arranged to the uppermost part is connected to the hot air generator 21, the front-end | tip opening of heating pipe 8c, 8c distribute | arranged to the lowermost part is the chimney 22 which attached the blower 23 ... 22 is connected. As a result, the hot air supplied from the hot air generator 21 is supplied to the uppermost heating pipes 8a, then passes through the intermediate heating pipes 8b, and then to the outside from the lowermost heating pipes 8c. Discharged. At this time, the temperature of the heating pipes 8c arranged below is gradually lowered by the heat radiation when the hot air passes through the continuous pipes 10 ... with respect to the temperature of the heating pipes 8a arranged above. Therefore, when the temperature of the heating pipes 8a disposed at the top reaches a temperature at which the dissolved waste plastic L is thermally decomposed, the temperature of the heating pipes 8c disposed below dissolves the waste plastic P. Conditions such as the diameter and length of the continuous pipes 10 (the number of heating pipes 8a) are selected so that the temperature is reached.
[0017]
In addition, the surface which the waste plastic L and decomposition gas which melt | dissolved, such as the outer peripheral surface of the heating pipe 8a ..., the inner surface of the tank main body 3, and the outer surface of the rotary screw 11, apply | coat liquefied glass (room temperature glass) which has heat resistance. . Since the heating pipes 8a, the tank body 3, the rotary screw 11 and the like are usually manufactured from a metal material such as steel, corrosion is likely to occur. In particular, when vinyl chloride is used as waste plastic, metal corrosion and oxidation proceed at a considerable rate due to the generated chlorine. For this reason, the surface of the heating tube 8a or the like is coated with the liquefied glass 25a ... to improve chemical resistance, corrosion resistance, durability, and the like. In this case, as shown in FIG. 5, for example, it is desirable to coat the surface of the heating tube 8 a with liquefied glass 25 a, 25 b, 25 c.
[0018]
Next, the configuration of the heat retaining device 4 constituting the main part of the present invention will be specifically described with reference to FIGS. 1 and 2.
[0019]
The heat retaining device 4 includes a heating device 7. The heating device 7 includes a heating unit 33, and the discharge unit of the heating unit 33 is connected to the upper one side of the heat retaining unit 6 through a pipe 35 having a valve 34 as shown in FIGS. 1 and 2. The suction part of the heating part 33 is connected to the other upper side of the heat retaining part 6 through a pipe 37 having a valve 36.
[0020]
As a result, the heat retaining oil C is heated by the heating unit 33 and then supplied to the space S between the outer plate 5 and the tank body 3 constituting the heat retaining unit 6 via the pipe 35 and in the space S. The heat retaining oil C constitutes a heating circulation circuit that is returned to the heating unit 33 via the pipe 37. In addition, 38 is an oil tank connected to the heating unit 33 via the valve 39, 40 is a control unit that controls various operations such as operation and heating temperature of the heating unit 33, and 41 includes a function of liquefying the vaporized heat retaining oil. It is an extension part. In this case, the control unit 40 has a function of detecting the heat retaining temperature Th by a temperature sensor (not shown) attached to the heat retaining unit 6 and controlling the heating temperature of the heating unit 33 based on the result.
[0021]
FIG. 4 shows the overall configuration of the oil reduction apparatus 1. In the figure, 51 is a crusher for crushing large waste plastic, 52 is a scrubber for neutralizing chlorine gas, 53 is a PH adjusting tank attached to the scrubber, and 54 is a condenser for liquefying the cracked gas , 55 is a cooler (cooling tower) for cooling the condenser 54, 56 is a pump, 57 is an oil / water separation tank for separating the obtained heavy oil and water, 58 is a filter, and 59 is a storage tank for heavy oil.
[0022]
Next, the entire operation of the oil reduction device 1 including the function of the heat retaining device 4 constituting the main part of the present embodiment will be described with reference to the drawings.
[0023]
First, hot air is supplied to the heating pipes 8a, 8a arranged at the top by the hot air generator 21. Thereby, the heating tubes 8a and 8a are heated to around 400 ° C. (vinyl chloride is 170 ° C.). The heating tubes 8c, 8c arranged at the lowermost part are heated to around 250 ° C. (70 ° C. in the case of vinyl chloride). In order to obtain such a temperature, the diameter and length of the continuous pipes 10 (the number of heating pipes 8a) are selected. And hot air is discharged | emitted from the chimneys 22 and 22 outside. At this time, the air is also drawn by the blower 23.
[0024]
On the other hand, solid waste plastics (polyethylene, polyesterol, vinyl chloride, etc.) P... At this time, the large waste plastic is crushed into small pieces by the crusher 51. Further, the rotary drive 11 is operated to rotate the rotary screw 11. As a result, the solid waste plastic P... Put into the hopper 14 is transferred by the rotary screw 11 and supplied into the tank body 2. The amount of waste plastic P supplied to the tank body 2 can be adjusted by arbitrarily controlling the rotational speed of the rotary screw 11.
[0025]
Moreover, 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 and melted by the relatively low temperature heating pipes 8c, 8c arranged at the bottom of the tank body 2. . The dissolved waste plastic L is stored inside the tank body 2, and the liquid level of the dissolved waste plastic L rises with an increase. When the rising liquid level reaches the uppermost heating tubes 8a and 8a, the heated plastic tubes 8b and 8a are heated, and the waste plastic L is vaporized by thermal decomposition. The foreign matter such as carbide floating on the upper surface of the waste plastic L is collected by the foreign matter collecting unit 13 by the rotary screw 11, and the upper surface of the waste plastic L is agitated and purified, so that the generation efficiency of decomposition gas is increased. It is done.
[0026]
On the other hand, the vaporized cracked 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 (corresponding to A heavy oil). The condenser 54 is constantly cooled by the coolant 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. After the impurities are removed by the filter 58, the heavy oil is supplied to and stored in the storage tank 59, and a part of the heavy oil is supplied to the hot air generator 21 for hot air. Used as fuel for the generator 21.
[0027]
On the other hand, the tank body 3 is kept warm by the heat retaining device 4 during a period when the operation of the liquefying and reducing device 1 is stopped at night or the like. In this case, the heat retaining oil C is heated by the heating unit 33 and supplied to the space S between the outer plate 5 and the tank body 3 constituting the heat retaining unit 6 via the pipe 35. Thereby, the tank main body 3 is heated to the preset heat retention temperature Th (70-400 degreeC). Further, the heat retaining oil C in the heat-exchanged space S is returned to the heating unit 33 via the pipe 37.
[0028]
Thereby, the waste plastic L remaining in the tank body 3 is maintained at the heat retention temperature Th. As a result, the start-up time at the time of re-operation is greatly shortened, and productivity and economy are dramatically improved.
[0029]
The embodiment has been described in detail above, but the present invention is not limited to such an embodiment, and the detailed configuration, shape, material, quantity, technique, and the like are within the scope not departing from the gist of the present invention. Can be changed arbitrarily.
[0030]
For example, although the tank body has exemplified a semi-cylindrical shape, for example, a tank body having an arbitrary shape with a lower width narrower than the upper side, such as an inverted triangle or an inverted trapezoid, can be used. In addition, the heat retaining device in the embodiment exemplifies the case where almost the entire outer surface of the tank main body is surrounded by the outer plate, but the heat insulating tube or the like that surrounds a part of the outer surface of the tank main body or flows the heat retaining oil is stored in the tank. You may attach to the surface of a main body.
[0031]
【The invention's effect】
As described above, the oil plastic reduction apparatus for waste plastic according to the present invention also serves as a dissolution tank and has a tank body whose lower width is narrower with respect to the upper side, and the tank body in the tank body. A heating mechanism in which a plurality of horizontal heating pipes arranged at predetermined intervals in the vertical direction along the inner surface of the main body are provided, and the temperature of the heating pipe arranged below is set lower than the temperature of the heating pipe arranged above And a thermal insulation device that heats the tank body in the thermal decomposition tank to a preset thermal insulation temperature when not in operation, the following remarkable effects are achieved.
[0032]
{Circle around (1)} Even when waste plastic remains in the pyrolysis tank, productivity and economy can be dramatically improved by greatly shortening the startup time for restarting.
[0033]
(2) According to a preferred embodiment, the heat retaining device includes a heat retaining portion in which a substantially entire outer surface of the tank body is surrounded by an outer plate, and a sealed space is provided between the outer plate and the tank main body. If it comprises the heating apparatus which circulates the heated oil for heat retention, in addition to being able to perform the effective heat retention at the time of non-operation, the heat insulation of the tank main body at the time of operation can be improved greatly.
[Brief description of the drawings]
[Figure 1]
A cross-sectional front view of a pyrolysis tank provided in the oil reduction device according to this embodiment
FIG. 2 is a block system diagram of a heat retention device provided in the oil reduction device,
FIG. 3 is a cross-sectional side view of a pyrolysis tank provided in the oil reduction device
FIG. 4 is a block system diagram showing an overall configuration of the oil reduction device,
FIG. 5 is a partial cross-sectional view of a heating tube in a pyrolysis tank provided in the oil reduction device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Oilification reduction apparatus 2 Pyrolysis tank 3 Tank main body 3o The outer surface 3s of a tank main body ... End surface 4 of a tank main body 4 Thermal insulation apparatus 5 Outer plate 6 Thermal insulation part 7 Heating apparatus 8a ... Heating pipe 9 Heating mechanism 10 Continuous pipe P ... Waste plastic S Space C Oil for heat insulation

Claims (5)

  In a waste plastic oil-reduction apparatus equipped with a pyrolysis tank that heats and decomposes waste plastic, a tank body that also serves as a dissolution tank and has a lower width narrower than the upper side, and this tank body Are provided with a plurality of horizontal heating pipes arranged at predetermined intervals in the vertical direction along the inner surface of the tank body, and the temperature of the heating pipe arranged below is set to the temperature of the heating pipe arranged above. A waste plastic oil-reduction apparatus characterized by comprising a thermal decomposition tank having a heating mechanism set at a low level, and a heat retention device that heats the tank main body in the thermal decomposition tank to a preset temperature when not in operation. .   The heat retaining device surrounds substantially the entire outer surface of the tank body with an outer plate, circulates a heat retaining portion provided with a sealed space between the outer plate and the tank body, and heat retaining oil heated in the heat retaining portion. A waste plastic oil-reduction apparatus according to claim 1, further comprising a heating device.   2. The waste plastic oil reduction apparatus according to claim 1, wherein the tank body is formed in a semi-cylindrical shape having semicircular end faces.   The plurality of heating tubes is composed of a plurality of straight portions formed by bending a single continuous tube in a zigzag shape, supplying hot air to the heating tube disposed at the top and heating disposed at the bottom. 2. The waste plastic oil reduction apparatus according to claim 1, wherein the waste plastic is exhausted from the pipe.   5. The waste plastic oil reduction apparatus according to claim 4, wherein a pair of said continuous pipes are arranged on the left and right.

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