JP2002180068A - Apparatus for forming waste plastic into oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact apparatus for forming a plastic into an oil, capable of converting the plastic to a high-quality mixed oil even if the plastic is a waste plastic including foreign matters mixed therewith. SOLUTION: A heating furnace 13 for heating a solvent and a circulating means having a circulating vessel 12 for storing the solvent are connected to a thermal decomposition vessel 10 to which the waste plastic is fed while holding the high-temperature solvent, and a means 21 for separating a decomposed oil and a solid impurity is connected to a discharging opening 17 of the decomposed oil through an openable gate 17a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil converting apparatus for thermally decomposing waste plastic with a high-temperature solvent in order to obtain purified oil from waste plastic.

[0002]

2. Description of the Related Art Waste plastic is dissolved in an oily solvent heated to about 200 ° C. to become a decomposed oil (mixed with a solvent). After it is vaporized for purification, it is cooled and condensed into a liquid, which can be recovered as a mixed oil (oily substance that does not fall under the classification of kerosene, light oil, etc.) that can be reused as fuel.

[0003] As a conventional waste plastic liquefaction apparatus for performing such treatment, for example, Japanese Patent Laid-Open No. 10-27 is disclosed.
No. 3676 is known. This apparatus includes a quench tower, an oil-water decomposition tank, and the like (not shown) in addition to the pyrolysis pot 40 and the heating furnace 40a shown in FIG. A solvent is put in the pyrolysis oven 40 in advance, and is heated from the outside of the oven by a heating furnace 40a. When the waste plastic is introduced from the introduction port 40b, it is dissolved in the solvent to form a decomposed oil. The light oil component of the cracked oil evaporates from the pyrolysis tank 40 and is sent to the quenching tower via the line 40c. There, it is cooled by the circulating cooling water and condenses into water and liquid oil. Thereafter, the oil and water separated in the oil / water separation tank are collected as a mixed oil. The recovered mixed oil is used as a fuel for heating an oil liquefier or a fuel for heating a greenhouse. In addition, the code | symbol 40d in FIG. 3 is a stirring blade, 40e is a heating burner.

[0004]

In the conventional apparatus as described above, the waste plastic and the solvent are put into the pyrolysis tank so that the weight ratio becomes about 1: 1 and the operation is started. Dissolves in the solvent to form a decomposed oil, while light oil or gas evaporates from the oil surface, gradually increasing the solvent concentration and reducing the decomposition rate of waste plastic that has not yet been decomposed. I was invited. In addition, since the viscosity of the solvent also becomes high, there is a problem that the inner surface of the kettle is easily scorched. Furthermore, since the cracked oil evaporates only from its surface, evaporation takes time. Therefore, in order to increase the amount of waste plastics processed per hour, the scale of the equipment must be increased or added,
There was a disadvantage that the equipment cost increased.

Further, solid impurities (paper,
Wood, cloth, leather, stone, sand, metal, glass, pottery, plant residue, animal residue, etc.)
Since the temperature was about 0 ° C., these solid impurities did not dissolve and accumulated in the pyrolysis vessel, which sometimes hindered the rotation of the stirring blade or ignited. In that case, the operation has to be stopped to remove the solid impurities, and time and effort have been wasted. Therefore, to avoid this situation,
The work to completely remove the solid impurities before the input of the waste plastic was not efficient in terms of time and economy.

SUMMARY OF THE INVENTION An object of the present invention is to provide a compact waste plastic oiling apparatus capable of efficiently converting even a waste plastic containing foreign substances into a high-quality mixed oil.

[0007]

According to the first aspect of the present invention, there is provided a waste plastic oiling apparatus for thermally decomposing waste plastic with a high-temperature solvent in order to obtain a purified oil from the waste plastic. Has the function of heating and storing the solvent (including cracked oil formed by pyrolysis of waste plastic) in a pyrolysis tank that holds the solvent (oil substance such as kerosene and waste oil) and receives waste plastic A circulation means is connected, and a separation means for separating the decomposed oil and the solid impurities is connected to an outlet of the decomposed oil via an openable gate.

[0008] According to the waste plastic liquefaction apparatus having such characteristics, since the high temperature solvent is constantly flowing by the circulation means, the concentration of the cracked oil is high around the waste plastic charged into the pyrolysis tank. And the decomposition of waste plastics is easy to proceed. Since the solvent is also stored in the circulation means, even if the pyrolysis tank (pyrolysis kettle) has the same capacity as the conventional one, the above concentration is suppressed because the total oil amount is large, and a large amount of waste plastic Can be quickly decomposed.

Further, since the cracked oil can be discharged from the outlet of the thermal cracking tank and a means for separating the cracked oil and the solid impurities is provided therein, the apparatus can be used even if the waste plastic contains solid impurities. Operation is possible without any trouble, and there is no need to clean the pyrolysis tank. This means that it is not necessary to carefully remove solid impurities from the waste plastic prior to putting the waste plastic into the pyrolysis tank, and therefore it is possible to efficiently convert waste plastic to oil.

The waste plastic charging section of the pyrolysis tank is preferably provided with a pretreatment means for crushing and concentrating (heating and melting) the waste plastic as a raw material.

In this case, since a bulky material such as styrene foam can be crushed into small pieces or reduced in volume by heat and then put into the pyrolysis tank, the size of the pyrolysis tank can be reduced. Become.

As described in claim 3, it is preferable to install two pyrolysis tanks, switchably connect each group to the circulating means, and provide a cooling means for each group.

In such an apparatus, since there are two thermal cracking tanks, while one of the tanks is discharging cracked oil (including the solvent), the thermal cracking is performed in another tank. It is possible to do. Therefore, the entire oil converting apparatus can continuously perform the thermal decomposition of the waste plastic and the purification thereof.

[0014] Further, since the cracked oil may ignite when exposed to air if it remains at a high temperature, it is necessary to lower the temperature when it is taken out of the pyrolysis tank. Can be done quickly. This is because the cooling means is provided at each base of the pyrolysis tank, so that the temperature of the cracked oil can be reduced in a short time in the pyrolysis tank before discharging. This allows the cracked oil to be discharged in a short time, so that continuous operation using two thermal cracking tanks proceeds smoothly.

It is preferable that an evaporating tank provided with a means for increasing the surface area of the heated cracked oil is provided as a means for purifying the cracked oil that has exited the separation means. In such an apparatus, since the surface area of the cracked oil is increased in the evaporation tank as the refining means, the evaporation of the cracked oil is promoted, and the production of the mixed oil can be performed efficiently.

Further, as means for heating the solvent or the decomposed oil, a pipe through which the fluid to be heated (that is, the solvent or the decomposed oil) flows, and a means for heating the pipe from outside. It is good to provide a heating furnace provided with. With such a heating furnace, it is easy to prevent the solvent or the decomposed oil from being scorched. This is because the solvent or the decomposed oil always moves by flowing into the pipeline of the heating furnace, and the decomposed oil does not stagnate at the portion in contact with the hot wall.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the waste plastic oil converting apparatus of the present invention will be described with reference to the drawings. 1 and 2 are process system diagrams of the waste plastic oil converting apparatus 1. In both figures, the thick solid line is the main line of the oiling process, the thick dashed line is the flow of solid impurities (and the pipeline, the same applies hereinafter), the thin two-dot chain line is the flow of chlorine-containing gas, the thin dashed line is the flow of fuel, Thin solid lines indicate the flows of circulating oil (solvent / cracked oil), respectively.

First, waste plastics as raw materials (for example, plastic wastes mainly composed of PE, PP, PS and partially containing PVC) are solid impurities (paper, wood, cloth,
400 kg is put into a crusher (not shown) in a state where small pieces of leather, stone, sand, metal, glass, pottery, plant residue, animal residue, etc.) remain mixed. 30m with the crusher
After being roughly crushed to a size of about m × 30 mm, the waste plastic is put into a volume-reducing solid machine 9 and concentrated to form pellet-like waste plastic having a specific gravity of about 0.6 to 0.7. The throughput of the pre-processing means including the crusher and the volume-reducing solid machine 9 is 800 kg per hour.
/ 2. Thereafter, 400 kg of the treated pellet-shaped waste plastic is supplied from the inlet 11 to the pyrolysis tank 10.
It is thrown into.

The pyrolysis tank 10 is a container provided with a take-out port 17 together with an opening / closing gate 17a at a lower part formed in a cone shape. A circulation path 16 is connected to the inside, and includes a circulation tank 12 for storing a solvent (oil substance such as kerosene, waste oil, etc.), a heating furnace 13 of a spiral tube type, a pump 14, and valves 15a and 15b. It leads to circulation means.

Open the valves 15a and 15b and open the gate 17
When the pump 14 is operated with the a closed, the solvent
The solvent is sent from the circulation tank 12 having a capacity of about 000 kg (that is, about 10 times the capacity of the pyrolysis tank 10) to the pyrolysis tank 10 through the spiral tube type heating furnace 13. Inside the heating furnace 13, a pipe 18 through which the solvent flows is spirally arranged from bottom to top, and a burner (not shown) for heating the solvent flowing through the pipe 18 from the outside is provided. I have. The solvent is heated to 200 ° C. while passing through the pipe 18 and sent to the pyrolysis tank 10. Since the solvent is constantly moving at a flow rate of 10 m ³ / h through the pipe line 18 at a considerable speed, the solvent does not burn during heating.

The waste plastic in the form of pellets in the pyrolysis tank 10 is dissolved in a solvent heated to 200 ° C. to become a decomposed oil. Undecomposed waste plastic and solid impurities are removed from the pyrolysis tank 1
0, only the generated cracked oil and the solvent circulate in the circulation path 16 and are again heated to 200 ° C.
Return to 0. Since the solvent (including the cracked oil) in the pyrolysis tank 10 is constantly moving and the total volume of the pyrolysis tank 10 and the circulation tank 12 is circulated over 4000 kg of the solvent, the waste plastic is circulated. The concentration of the surrounding solvent is unlikely to increase, and the decomposition rate hardly decreases.

In the pyrolysis tank 10 and the circulation tank 12, chlorine in the waste plastic is generated as a gas, and the chlorine-containing gas generated in these steps flows from the upper part of each of the tanks 10 and 12 into a gas absorption tank ( (Not shown), and drained after alkali cleaning.

As described above, if the solvent (including the cracked oil) is continuously circulated for about 30 minutes, the waste plastic put into the pyrolysis tank 10 is completely decomposed.
15b is closed to shut off the circulation path 16. Then, cooling water is circulated through a water-cooled jacket 20 attached around the thermal decomposition tank 10 to start cooling the thermal decomposition tank 10.

After confirming by a thermometer (not shown) that the temperature of the cracked oil in the cracking tank 10 has dropped to about 50 ° C., the gate 17 a at the lower part of the cracking tank 10 is opened, and All the cracked oil and solid impurities therein are sent to the centrifuge 21. Kerosene may ignite when exposed to air at 40 ° C, but cracked oil contains components other than kerosene, so if the temperature drops to 50 ° C it will ignite even if exposed to air Never.

The above-described steps of about 60 minutes for the thermal decomposition and cooling are regarded as one cycle, and the two thermal decomposition tanks 10 and 30 having the same structure are operated while being shifted by a half cycle (that is, 30 minutes). I do. That is, while cooling the pyrolysis tank 10, in the pyrolysis tank 30, the solvent is circulated between the pyrolysis tank 10 and the circulation tank 12, so that the newly prepared
Pyrolyze 00 kg of waste plastic. By repeating this, the thermal decomposition of the waste plastic can be continuously performed as the whole oil converting apparatus 1.

Therefore, cracked oil mixed with solid impurities is sent to the centrifugal separator 21 alternately (every 30 minutes) from the two pyrolysis tanks 10 and 30. And the separator 21
Separates cracked oil from solid impurities by the action of centrifugal force. The separated cracked oil is heated in a spiral tube heating furnace 2
After passing through 3, the remaining solid impurities are dropped into a waste liquid tank 25 and then incinerated. The chlorine-containing gas generated in the waste liquid tank 25 or generated at the time of incineration is alkali-washed in a gas absorption tank (not shown), and is drained together with the processing liquid.

The cracked oil sent to the heating furnace 23 is heated to about 360 ° C. from the outside of the pipe 28 by a burner (not shown) while moving in the pipe 28 spirally arranged. , To the evaporation tank 24. Since the decomposed oil always moves in the pipe 28 at a flow rate of 10 m ³ / h, it does not burn. Then, the decomposed oil is dropped into the evaporating tank 24 so as to gradually drop from the oil feed port 26 having a small inner diameter provided at the upper part of the evaporating tank 24. In this way, the cracked oil is made thinner or dropped and dropped, and compared with the case where the cracked oil is evaporated only from the surface of the cracked oil stored in the thermal cracking tank as in the conventional oiling device, The surface area of the decomposed oil can be increased and the cracked oil is quickly evaporated because it is heated to a high temperature of about 360 ° C.

The steam of the cracked oil generated in the evaporating tank 24 is sent to the condenser 31, and the cracked oil that has not evaporated is sent again to the heating furnace 23 by a circulation path (not shown). When the circulation is further continued, heavy oil accumulates at the bottom of the evaporating tank 24,
This is taken out and used as fuel for the heating furnaces 13 and 23.

The steam of the decomposed oil sent to the condenser 31 is condensed by the cooling water to become a high-quality mixed oil, and is recovered in the product receiving tank 32 after removing water. After the chlorine gas is further removed here, it is sent to the product tank 33. The mixed oil is recovered at a rate of approximately 1 m ³ / h. Note that the mixed oil recovered by this oiling device is a high-quality mixed oil as compared with the conventional oil because the solid impurities are efficiently removed by the centrifugal separator 21.

By the way, the waste plastic oil converting apparatus according to the present invention is not limited to the above embodiment. For example,
In this embodiment, a water cooling jacket is used for the cooling means of the pyrolysis tank. However, a cooling tank may be provided between the outlet of the pyrolysis tank and the separator to cool the cracked oil with cooling water. . It is also conceivable to attach a sprayer to the oil supply port for the evaporation tank. In this case, since the decomposed oil is diffused into the evaporating tank in the form of a mist, the surface area of the decomposed oil further increases, and the evaporation proceeds more quickly.

[0031]

According to the waste plastic oil converting device of the present invention, since the solvent is circulated, the concentration of the solvent around the waste plastic does not easily become high, and even in a pyrolysis tank having the same capacity as that of the conventional device. Waste plastics can be decomposed quickly, which is efficient. Also, by taking out all the decomposed oil generated in the pyrolysis tank and solid impurities such as paper and wood chips and applying the same to a separator, only the decomposed oil can be recovered. Even if it exceeds, there is no hindrance to the operation of the apparatus, and the operation of removing impurities from waste plastic in advance, which has been conventionally performed, can be omitted, and the efficiency is economical and time efficient.

According to the second aspect of the present invention, the bulk of the waste plastic to be charged can be reduced.
The thermal decomposition tank can be made compact, and the production cost of the equipment can be reduced. There is also an advantage that the space required for installation is small.

Further, in the oil converting apparatus according to the third aspect, by shifting the operation cycle of the two thermal decomposition tanks, it is possible to decompose waste plastic while cooling the decomposed oil on one side. As a result, continuous operation of the entire liquefaction apparatus becomes possible. In particular, since the pyrolysis tank (cracked oil) can be cooled in a short time, it can be discharged earlier and continuous operation can be smoothly performed. Therefore, the amount of mixed oil recovered per hour increases.

According to the fourth aspect of the present invention, the cracked oil is evaporated in a short time, which has conventionally taken a long time.

Further, in the oil converting apparatus according to the fifth aspect, since the solvent and the decomposed oil are constantly moving in the pipeline of the heating furnace, they are not scorched. In addition, the oil temperature can be easily kept uniform as compared with the conventional heating method in which the pyrolysis tank is cooked directly from below.
Therefore, the decomposition of the waste plastic and the evaporation of the generated cracked oil proceed smoothly.

[Brief description of the drawings]

FIG. 1 is a process system diagram relating to an apparatus for converting waste plastic into oil according to the present invention.

FIG. 2 is a process system diagram relating to an apparatus for converting waste plastic into oil according to the present invention.

FIG. 3 is a conceptual diagram showing a main part of a conventional oiling device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oil-ized apparatus 10/30 Thermal decomposition tank 12 Circulation tank 13.23 Heating furnace 16 Circulation path 18.28 Pipe line 20 Water cooling jacket 21 Centrifuge 24 Evaporation tank 33 Product tank

Claims (5)

[Claims] 1. In order to obtain refined oil from waste plastic,
An oiling device that thermally decomposes waste plastic with a high-temperature solvent, and connects a circulating means that has the function of heating and storing the solvent to a pyrolysis tank that holds the high-temperature solvent and receives the waste plastic. An apparatus for liquefying waste plastics, wherein a means for separating cracked oil and solid impurities is connected to an outlet of the cracked oil via an openable gate. 2. The waste plastics liquefaction apparatus according to claim 1, wherein a pre-treatment means for crushing and concentrating waste plastics as a raw material is provided in a waste plastic input section of the pyrolysis tank. . 3. The apparatus according to claim 1, wherein two pyrolysis tanks are installed, each of the groups is switchably connected to the circulating means, and a cooling means is provided for each of the groups. The waste plastic oil liquefaction device described in the above. 4. An evaporating tank provided with a means for increasing the surface area of the heated oil as a means for purifying the cracked oil that has exited the separation means. A waste plastic oil liquefaction apparatus according to claim 1. 5. A heating furnace provided with a pipe through which a fluid to be heated flows and means for heating the pipe from outside as a means for heating the solvent or the cracked oil. 4. The waste plastic oil liquefaction apparatus according to any one of 4.