JP2608376B2 - Plastic waste treatment equipment - Google Patents

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 processing plastic waste to recover high quality oil and the like.

[0002]

2. Description of the Related Art Apparatuses for recovering hydrocarbon oil from plastic waste are disclosed, for example, in JP-A-59-174691, JP-A-2-29492, and JP-A-3-867.
As disclosed in, for example, Japanese Patent Publication No. 90-90, a vaporous product obtained by thermally decomposing plastic waste is led to a catalyst tank filled with a catalyst such as zeolite to be contact-converted, and after passing through the catalyst tank. There is one that recovers high-quality oil having a small molecular weight by cooling steam with a cooler.

[0003]

However, in the above-mentioned conventional apparatus, the steam introduced into the catalyst tank due to the variation in the particle size and temperature of the catalyst passes through the catalyst tank without being sufficiently decomposed or decomposed. An oil having an undesired high molecular weight may be mixed in the oil recovered by the recombination of the separated molecules after passing through the catalyst tank, and a considerable amount of wax may be generated at room temperature. In view of this, attempts have been made to increase the recovery rate of high quality oil by providing a plurality of catalyst tanks to allow steam to pass in order or to repeatedly return steam to the catalyst tank. But,
The former means complicates the structure of the apparatus, significantly increasing the maintenance and management load thereof, and also requires an extremely large installation space for the apparatus, and requires a large amount of energy to heat the catalyst tank. In the latter means, a considerable portion of the catalyst tank is occupied by circulating steam, which reduces the processing capacity of the apparatus, unnecessarily lengthening the time required for oiling, and preventing the catalyst tank from lowering in temperature. It is necessary to heat the steam on the way back to the furnace, resulting in poor thermal efficiency.

An object of the present invention is to provide a processing apparatus capable of efficiently recovering high-quality oil and the like, and having a simple and compact structure.

[0005]

According to a first aspect of the present invention, there is provided a screw feeder (41) and a combustion chamber (40) covering the outer periphery of the screw feeder (41), and one end of the screw feeder (41). Melter and decomposer (4) that heats the plastic waste injected into the combustion chamber by the heat of combustion in the combustion chamber (40) while being conveyed by a screw feeder (41), and plastic waste discharged from the melter and decomposer (4) A pipe (51) through which the melt of the product is led, and a reheating chamber (50) surrounding the pipe, and the reheating chamber (5) is provided.
0), a reheating device (5) for heating the melt by the heating gas supplied thereto, and a catalyst tank (4) to which the vapor-like products generated in the melt decomposition device (4) and the reheating device (5) are led. 71), a separation tank (72) connected to the upper part of the catalyst tank (71) and separating the steam passing through the catalyst tank (71) according to its specific gravity, and a heat medium surrounding at least the catalyst tank (71). A reactor (7) having a tank (700)
And a heating medium heating device (6) for heating the heating medium oil,
The heat medium oil heated by the heat medium supply device (6) is supplied to the central axis (41) of the screw feeder (41) of the melting and decomposing device (4).
a) and the heating medium oil (700) of the reaction device (7), and the heating medium oil discharged from the central shaft (41a) and the heating medium tank (700) is supplied to the heating medium heating device (6).
And the exhaust gas from the combustion chamber (40) of the melting and decomposing device (4) is guided to the reheating chamber (50) of the reheating device (5), and the exhaust gas from the reheating chamber (50) is The above object is achieved by a plastic waste treatment apparatus which is guided to a heat medium heating device (6) as a heat source for heating a heat medium oil. According to a second aspect of the present invention, in the plastic waste treatment apparatus of the first aspect, the reheating device (5) includes:
Heating means (53, 54) for heating exhaust gas guided from the melting and decomposing device (4) are provided.

[0006]

According to the first aspect of the present invention, the plastic waste put into one end of the screw feeder (41) of the melt decomposition device (4) is conveyed in one direction with the rotation of the screw feeder (41). It is heated from inside and outside by the heat from the combustion chamber (40) and the heat of the heat transfer oil passing through the central shaft (41a). In this heating process, the substance having a low melting point is vaporized and guided to the catalyst tank (71) of the reactor (70). The substance having a high melting point is discharged from the screw feeder (41) in a liquid state, and is discharged from the pipe (5) of the reheating device (5).
It is led to 1). In the reheating device (5), the pipe (5)
The liquid passing through 1) is heated and vaporized by the heat of the reheating chamber (50), and the vaporous product is led to the catalyst tank (71) of the reactor (7). In the reactor (7), the vaporous product guided to the catalyst tank (71) is guided to the upper separation tank (72) while being decomposed by reacting with the catalyst.
In the separation tank (72), the steam is separated according to the difference in specific gravity. The separated steam is cooled, for example, and recovered as oil. In this process, the catalyst tank (71) is maintained at a predetermined temperature by the heat of the heat transfer oil guided to the heat transfer tank (700). The exhaust gas from the combustion chamber (40) of the melting and decomposing device (4) is guided to the reheating device (5) and used as a heat source for the reheating chamber (50). It is guided to the heat medium heating device (6) and is used as a heat source for heating the heat medium oil. According to the second aspect of the present invention, the shortage of heat due to the exhaust gas guided to the reheating device (5) is compensated by the heating means (53, 54).

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a view showing the overall configuration of a plastic waste oil-purifying apparatus according to the present embodiment.
A raw material crusher 2 for crushing the plastic waste input into the crusher 1 is a raw material blower for sending out the plastic waste crushed by the raw material crusher 1 by wind power. Raw material blower 2
Is separated from the air by the cyclone 30 of the raw material input device 3, then dropped from the hopper 31, extruded sequentially by the horizontal cylinder 32 and the vertical cylinder 33, and injected into the raw material melting and cracking furnace 4.

The raw material melting and cracking furnace 4 conveys plastic waste input from the raw material input device 3 by a screw feeder 41 disposed at the center of the combustion chamber 40,
0 and the screw feeder 4
The plastic waste is heated and thermally decomposed from inside and outside by the heat medium oil flowing in the inside of the central shaft 41a in the direction opposite to the conveying direction of the plastic waste. The heating temperature in the raw material melting and decomposing furnace 4 is changed according to the type of the plastic waste to be charged, but it is generally preferable to set it to 300 to 600 ° C. A plastic (for example, polypropylene) that is thermally decomposed at a relatively low temperature by the heat of the raw material melting and decomposing furnace 4.
The thermal decomposition temperature (220 ° C.) is vaporized during conveyance by the screw feeder 41 and is discharged from the vapor discharge port 43. On the other hand, most of the plastics that thermally decompose at a relatively high temperature (for example, polyethylene-pyrolysis temperature of 360 ° C.) reach the terminal end of the screw feeder 41 in a molten state and are discharged from the melt discharge port 44.

The melt discharged from the melt discharge port 44 is pumped by a pump 45 to the reheating boiler 5. Exhaust gas discharged from the exhaust port 46 of the combustion chamber 40 is guided to a temperature adjustment chamber 52 of the reheating boiler 5 which will be described later. Reference numeral 47 denotes a valve for taking out a residue such as a carbide discharged from the melt outlet 44 while being mixed with the melt.

The reheating boiler 5 includes a reheating chamber 50 and a raw material melting and cracking furnace 4 provided in a process preceding the reheating chamber 50.
Raw material heating pipe 51 through which the melt from
And a temperature control chamber 52 provided adjacent to the temperature control chamber 0. An oil burner 53 and a fan 54 are connected to the temperature control chamber 52, and the oil burner 53 and the fan 54 compensate for the shortage of the calorific value of the exhaust gas from the raw material melting and decomposing furnace 4 so that the reheating chamber 50 is maintained at a constant temperature. Is held. That is, when the temperature of the reheating chamber 50 detected by the temperature detector 55 falls below a desired set value, the oil burner 53 is ignited, and the opening of the control valve 56 is adjusted so that the amount proportional to the combustion amount is reduced. Air is blown from the fan 54. When the amount of heat of the exhaust gas from the raw material melting and decomposing furnace 4 is large and the temperature of the reheating chamber 50 is higher than a desired temperature, only the blowing from the fan 54 is performed to adjust the temperature of the temperature adjusting chamber 52. Function.

The temperature of the reheating chamber 50 may be changed as appropriate depending on the composition of the plastic melt and the like.
It is preferable to set the temperature to 0 to 500 ° C. If the temperature is lower than 350 ° C., the thermal decomposition of the plastic waste is delayed, and the recovery of high-quality oil having a low molecular weight may be significantly reduced.
If the temperature exceeds 00 ° C, there is a high risk of ignition depending on the type of plastic waste. The melt that passes through the raw material heating pipe 51 due to the heating in the reheating chamber 50 is thermally decomposed and is discharged as a vapor from the vapor discharge port 57. The temperature of the discharged steam is monitored by a thermometer 58, and when the steam temperature is lower than a desired temperature, the set temperature of the reheating chamber 50 is changed to a higher temperature. Also, the reheating chamber 50
Is taken out from the exhaust port 59 and used as a heat source of the heat medium boiler 6. The heat medium boiler 6 heats the heat medium oil by the exhaust heat of the reheating chamber 50 and the oil burner 60. A part of the heating medium oil heated by the heating medium boiler 6 is supplied to the screw feeder 41 of the raw material melting and cracking furnace 4, and the rest is supplied to the reaction device 7.

[0013] The steam discharged from the steam outlet 43 of the raw material melting and cracking furnace 4 and the steam outlet 57 of the reheating boiler 5 are merged downstream thereof and led to the reactor 7. FIG.
As shown in more detail, the reaction apparatus 7 includes a substantially cylindrical catalyst vessel 71 and a distillation vessel 7 inside a substantially cylindrical reaction vessel 70.
2 is housed in a state of being connected up and down. Inside the catalyst tank 71, there is provided a catalyst support plate 711 provided with a large number of through holes for passing the steam taken in from the steam inlet 710, and a catalyst which reacts with the steam from the steam inlet 710 is provided above the catalyst supporting plate 711. 712 are filled. As the catalyst 712, various catalysts capable of reforming the oil vapor so as to increase the amount of high-quality oil components, such as those which catalytically convert oil vapor to reduce its molecular weight, such as zeolite, are used. Reference numeral 713 denotes a dispersion plate having a large number of through holes through which steam reacted with the catalyst 712 passes, and 714 denotes a catalyst 71.
2 is an inspection port for performing inspection and replenishment.
1 is a thermometer for monitoring the temperature in the apparatus. Also, the catalyst tank 71
And the distillation tank 72 are connected coaxially with their flanges 716 and 720 facing each other.

The distillation tank 72 separates the vapor rising from the catalyst tank 71 in accordance with the specific gravity. Inside the distillation tank 72, three fractionation chambers 724 to 72 divided by partition plates 721 to 723 are provided.
6 are provided. As shown in FIG. 3 and FIG. 4, a large number of slot pipes 727 serving as flow paths for steam rising in the distillation tank 72 are planted in the partition plates 721 to 723 and accumulated on the partition plates 721 to 723. Downcomers 728 for dropping steam having a high specific gravity to the lower stage are attached to the fractionation chambers 724 to 726 so as to be shifted in position. The upper end of the slot pipe 727 is covered with a baffle cap 729, and the steam rising in the slot pipe 727 passes through the gap S between the slot pipe 727 and the baffle cap 729 as shown by an arrow in FIG.
After being evenly dispersed on the upper surfaces of 21 to 723, the distillation tank 72
Rise inside.

As shown in FIG. 1 and FIG.
Are provided with discharge pipes 730 to 732 for discharging steam accumulated in the fractionating chambers 724 to 726. Discharge pipe 730
-732 are discharged from the coolers 8 independent of each other.
It is cooled at 0-82, which liquefies the vapor. The oil obtained by the cooling action of the coolers 80 to 82 is stored in the oil storage tank 9.
Collected at 0-92.

The catalyst tank 71 and the distillation tank 72 include a heating medium tank 70.
It is surrounded by zeros. The heat medium oil heated by the heat medium boiler 6 is supplied to the heat medium tank 700 at the heat medium oil inlet 701 at the lower end.
Injected from. The heat transfer oil that has reached the upper end of the heat transfer tank 700 is taken out from the heat transfer oil outlet 702, and the raw material melting and cracking furnace 4
Is pumped to the heat medium boiler 6 by the pump 61 together with the heat medium oil discharged from the screw feeder 41. FIG.
As shown in the figure, a control valve 703 is provided in a path of the heat transfer oil from the heat transfer medium boiler 6 to the heat transfer tank 700. The control valve 703 is connected to the temperature detector 7
15 according to the temperature of the catalyst tank 71 detected by the heating medium tank 700.
The supply amount of the heat transfer oil is changed to keep the temperature of the catalyst tank 71 constant. The temperature of the catalyst tank 71 may be appropriately determined according to the type of the catalyst to be used, the boiling point of the oil to be recovered, and the like, but is generally preferably set to 300 to 400 ° C.

As shown in FIG. 3, a large number of cutouts 703 are formed in the outer peripheral portions of the flanges 716 and 720 protruding from the heat medium tank 700 to allow the heat medium oil to pass therethrough. In addition,
Upper lid 735 and flange 736 of distillation tank 72 (see FIG. 2)
Is also provided with a similar notch. In FIG. 3, reference numeral 737 denotes a bolt for connecting the flanges 716 and 720, and the upper lid 735 and the flange 736 are also connected by bolts arranged similarly. As shown in FIG. 2, the reaction vessel 70 is provided with a catalyst tank 71 and a distillation tank 72 by loosening bolts (not shown) connecting the intermediate flanges 705 and 706.
Can be divided at the same position as the division position. This is a measure for facilitating maintenance of the catalyst tank 71 and the distillation tank 72. In this embodiment, the reaction vessel 70
Is covered with a heat insulating material 705 to improve thermal efficiency.

In the oil converting apparatus having the above configuration, the raw material crusher 1
The plastic waste that has been introduced into the furnace and crushed into granules or small lump is introduced into the raw material melting and cracking furnace 4 through the raw material blower 2 and the raw material charging device 3 and is vaporized by the raw material melting and cracking furnace 4 or the reheating boiler 5. It is supplied to the reactor 7. In this steam generation process, the plastic waste is vaporized in two stages according to its thermal decomposition temperature, so that it is not necessary to heat the material having a low thermal decomposition temperature in the reheating boiler 5, Heat distribution efficiency is improved. Moreover,
Since the exhaust heat of the raw material melting and cracking furnace 4 is used as a heat source of the reheating boiler 5, the thermal efficiency is further improved.

The steam guided to the reactor 7 is supplied to the catalyst tank 71.
After reacting with the catalyst 712 to reform the catalyst to one having a small molecular weight, the catalyst rises from the catalyst tank 71 to the distillation tank 72. The steam guided to the distillation tank 72 passes through the slot pipes 727 of the partition plates 721 to 723 and is sequentially guided to the fractionating chambers 724 to 726. In the rising process of the steam, the partition plate 721
723, in particular, the baffle cap 729 creates a large resistance to the flow of steam, and the higher the specific gravity, the slower the upward movement. Thereby, the vapor having the highest specific gravity is stored in the lower fractionation chamber 724, the vapor having the lowest specific gravity is stored in the upper fractionation chamber 726, and the steam having the medium specific gravity is stored in the middle fractionation chamber 725. Oil vapors having different specific gravities are discharged from the discharge pipes 730 to 732. As a result, the oil storage tank 90
Heavy oil, light oil such as light oil or kerosene in the oil storage tank 91, light oil used for gasoline in the oil storage tank 92, and heavy oil mixed with light kerosene or gasoline. It is rare.

When the vapor is recombined in the ascent process in the distillation tank 72 to increase the molecular weight, the vapor is sometimes partially liquefied from the downcomer 728 to the lower fractionation chamber 72.
4,725. The steam and its liquefied components that fall from the downcomer 728 in the lowermost diversion chamber 724 are returned to the catalyst tank 71, reformed again in the catalyst tank 71, and
Rise to This repetition promotes the reforming of steam having a large specific gravity, and increases the recovery rate of high quality oil. In addition, since the distillation tank 72 is also heated with the heat transfer oil, the thermal decomposition of steam is promoted inside the distillation tank 72, and the recovery rate of high quality oil is further increased.

The amount of steam returned from the distillation tank 72 to the catalyst tank 71 is such that sufficient reaction vapor is sequentially discharged from the exhaust pipes 730 to 732, and that thermal decomposition is promoted in the distillation tank 72. This is far less than that in which the steam passed through the catalyst tank is repeatedly returned to the catalyst tank. Therefore, the processing capacity of the catalyst tank 71 is not significantly impaired by the reflux of the steam. Since the processing capacity of the distillation tank 71 is high,
The time required for oiling can be reduced by increasing the amount of steam supplied to the reactor 7 per unit time. Since the catalyst tank 71 and the distillation tank 72 are vertically connected, almost no heat loss occurs when moving the steam between the catalyst tank 71 and the distillation tank 72, and even when returning the steam to the catalyst tank 71, No pumping means such as a pump is required. For this reason, high-quality oil can be efficiently collected with little energy, and the operating cost of the liquefaction apparatus can be greatly reduced as compared with the related art. Catalyst tank 71 and distillation tank 72
The space required for installation is small, and high-quality oil can be sufficiently recovered by a single reaction device 7. Therefore, the configuration of the entire oil conversion device is reduced in size and simplified, and its maintenance and management is facilitated.

The reactor 7 in the embodiment is merely an example, and the present invention is not limited to the embodiments shown in FIGS.
For example, two or four or more partition plates may be provided.
In the embodiment, the heat medium tank 700 is provided on the outer periphery of both the catalyst tank 71 and the distillation tank 72. However, the heat medium tank 700A may be provided only on the catalyst tank 71 side as shown in FIG. As shown in FIG. 6, band heaters 740 to 742 may be separately provided on the outer periphery of fractionating chambers 724 to 726, and the temperatures of chambers 724 to 726 may be controlled independently of each other. The reheating boiler 5 is applicable not only to the processing apparatus targeted by the present invention, but also to any type of plant that can use waste heat.

As described above, in the treatment apparatus of the present invention, the vaporous product and the liquid matter are discharged from the screw feeder of the melt decomposition apparatus, and the former is directly guided to the catalyst tank of the reactor, while the latter is recycled. The heating medium is further heated and vaporized and then guided to the catalyst tank. The heating medium oil heated by the heating medium heating apparatus is guided to the heating medium tank of the reaction apparatus and the central axis of the screw feeder of the melting and decomposing apparatus. At the same time, the exhaust gas from the melting and cracking device was used as the heat source for the reheating device, and the exhaust gas from the reheating device was used as the heat source for the heating medium heating device. In addition, a small processing device can be realized.

[0024]

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire configuration of an oiling device according to one embodiment of the present invention.

FIG. 2 is a cross-sectional view showing details of the reaction apparatus of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG. 2;

FIG. 4 is an enlarged view of an IV section in FIG. 2;

FIG. 5 is a view showing a modification of FIG. 2;

FIG. 6 is a view showing another modification of FIG. 2;

[Explanation of symbols]

 4 Raw Material Melting Furnace 5 Reheating Boiler 7 Reactor 70 Reaction Vessel 71 Catalyst Vessel 72 Distillation Vessel 700,700 A Heat Medium Vessel 712 Catalyst 724,725,726 Separation Chamber 740,741,742 Band Heater

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-48-94775 (JP, A) JP-A-49-23874 (JP, A) JP-A-49-23873 (JP, A) 180995 (JP, A) JP-A-50-53475 (JP, A) JP-A-4-225092 (JP, A)

Claims (2)

(57) [Claims] 1. A screw feeder (41) and its screw
Combustion chamber (40) covering the outer circumference of the clew feeder (41)
And at one end of the screw feeder (41)
The plastic waste to be fed is
The fuel in the combustion chamber (40) is transported by the
A melting and decomposing device (4) for heating by burning heat ; and the plastic discharged from the melting and decomposing device (4).
Pipe (51) through which the molten material of waste
And a reheating chamber (50) surrounding the reheating chamber.
Heating the melt by the heating gas supplied to (50)
The reheating device (5), the melting and decomposing device (4) and the reheating device (5).
Each of the catalyst tanks (7
1) and connected to the upper part of the catalyst tank (71) to
The vapor passing through the medium tank (71) is separated according to its specific gravity.
Separation tank (72) and at least the catalyst tank (71)
A reactor (7) having a surrounding heat medium tank (700)
And a heat medium heating device (6) for heating the heat medium oil, wherein the heat medium oil heated by the heat medium supply device (6) is
The screw feeder (41) of the melt decomposition device (4)
Central axis (41a) and the heating medium of the reactor (7)
Each is guided to the tank (700),
The shaft (41a) and the heat medium tank (700)
Heat medium oil is collected in the heat medium heating device (6) and discharged from the combustion chamber (40) of the melting and decomposing device (4).
The gas is supplied to the reheating chamber (50) of the reheating device (5).
And exhaust from the reheating chamber (50).
Gas serves as a heat source for heating the heat transfer medium oil,
An apparatus for treating plastic waste, which is guided to a storage (6) . 2. The reheating device (5) is provided with the molten component.
Heating means for heating the exhaust gas guided from the dissolving device (4)
(53, 54) is provided.
Item 6. An apparatus for treating plastic waste according to Item 1.