JP3372509B2 - Oil recovery device for waste plastic - Google Patents

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 recovery apparatus for efficiently recovering high-quality fuel oil from waste plastics separately collected from municipal waste or waste plastics recovered as industrial wastes. Regarding

[0002]

2. Description of the Related Art Conventionally, as a method of recovering oil by thermally decomposing waste plastics, a method is known in which the carbon skeleton of the waste plastics is cut at a temperature of about 400.degree. . Approximately 500 to 1,000 kcal / kg required for thermal decomposition of waste plastic
As a means for applying heat of (plastic), in addition to a method in which a molten plastic is circulated by a pump and energy is applied by a heating furnace provided on the way, disclosed by JP-A-9-71684 by the applicant of the present invention. The proposed invention has been proposed.

That is, according to such a basic technique, as shown in FIG. 3, waste plastic P is roughly crushed to a particle size of about 200 mm, and then, through a waste plastic supply line 110, in a dechlorination means 1 such as a rotary kiln, waste plastic P is used. Is mixed with high temperature sand S from the sand circulation line 7 and heated to a temperature of 250 to 350 ° C. to remove chlorine. The waste plastic P containing substantially no chlorine content due to its own composition and / or the waste plastic P from which the chlorine content has been substantially removed by the dechlorination means 1 is discharged from the extraction line 9 as heat generated by a fluidized bed or a stirring tank. It is sent to the disassembling means 2.

In the thermal decomposition means 2, the sand removal line 20
An additive T or the like is added from the higher temperature sand S and / or the additive supply line 10, and the waste plastic P is directly heated by the sand S having a large specific surface, and the temperature is about 350 to 500 ° C.
Preferably by heating to 400-480 ° C,
It is thermally decomposed into a gaseous thermal decomposition product (gaseous high boiling point oil, low boiling point oil, low molecular gas) and a thermal decomposition residue is produced as a by-product. The pyrolysis residue is sent to the fluidized bed type combustion furnace 3 through the line 17.

A first gas-liquid separation means 4 consisting of a reflux tower is connected above the thermal decomposition means 2. First
In the gas-liquid separation means 4, the gaseous pyrolysis products supplied from the lower pyrolysis means 2 and rising, and the pyrolysis gaseous products supplied from above by the liquid disperser 42 such as a spray nozzle and descending. The low boiling point oil cooled or adjusted to a temperature lower than the temperature is brought into countercurrent contact, and the gaseous thermal decomposition product is a liquid high boiling point oil (boiling point 250 ° C. or higher) and low boiling point component (boiling point 250 ° C.).
It is separated into the following gaseous low boiling point oil and low molecular gas). The high boiling point oil is returned to the thermal decomposition means 2. Note that this boundary temperature of 250 ° C. can be set to 2 if necessary.
It can be freely set in the range of 00 to 400 ° C.
The gaseous low boiling point oil and low molecular weight gas separated from the high boiling point oil by the first gas / liquid separating means 4 are the second gas / liquid separation consisting of a fractionating tower or a stripping tower from the uncondensed gas extraction line 13. Introduced into means 5.

In the second gas-liquid separating means 5 connected in series to the first gas-liquid separating means 4, a cooler 5a is arranged above the upper filling part, and the gas is cooled to room temperature by the cooler 5a. Thus, the low boiling point oil that is liquid at room temperature is stored in the lower bottom portion, and the low molecular gas that is gaseous at room temperature is sent to the fluidized bed combustion furnace 3 through the line 16 and is used as fuel for the combustion furnace 3. A part of the low boiling point oil separated by the second gas-liquid separating means 5 is returned to the liquid disperser 42 of the first gas-liquid separating means 4 through the circulation line 23 to wash the high boiling point oil. -Used for collection. Further, as each of the gas-liquid separating means, for example, a packed tower or a tower having a plurality of trays vertically arranged in the tower is used.

Further, organic matter such as solid pyrolysis residue (carbonaceous matter), solid foreign matter, and non-liquefied thermosetting resin produced by the pyrolysis means 2 is taken out by a screw feeder or the like, and burned as described above. It is introduced into the furnace 3. The combustion furnace 3
, A fluidized bed using sand S as a medium is formed by blowing air, the organic substances and the organic substances attached to the sand S are completely burned, and the sand S is heated to 500 to 950 ° C. The sand S is separated from the ash and recycled to the dechlorination means 1 and the thermal decomposition means 2 via lines 20, 11 and 7.

With the above-mentioned structure, the conventional technique has the following effects. That is, in the thermal decomposition means 2, since the waste plastic P is directly heated by the high temperature sand S having a large specific surface area, the caulking trouble on the heat transfer surface as in the conventional indirect heat exchanger is avoided, and the operation is stable. However, long-term continuous operation becomes possible. The pyrolysis residue produced as a by-product adheres to and grows on the sand S, but the sand S constantly flows,
It circulates between the fluidized bed type combustion furnace 3 and the thermal decomposition residue is burnt and disappears in the combustion furnace 3 to be easily heated and regenerated.

Next, the high-boiling point oil is separated from the low-boiling point component by the first gas-liquid separating means 4, returned to the thermal decomposition means 2, and further reheated and thermally decomposed to produce a low-boiling point oil. The yield of low boiling point oil is increased, and the quality and storage stability of oil are improved.

Furthermore, since a part of the low boiling point oil separated from the low molecular gas by the second gas-liquid separating means 5 is returned to the first gas-liquid separating means 4, the high boiling point oil is converted into the first gas-liquid. Even if it tries to pass through the separating means 4 by mistake, it comes into contact with the low boiling point oil, is trapped therein, is dispersed therein, and is surely refluxed to the thermal decomposition means 2 side. Therefore, the wax component (high boiling point oil) does not migrate or mix into the low boiling point oil side, and a high quality low boiling point oil can be obtained.

Furthermore, the organic matter such as the thermal decomposition residue produced by the thermal decomposition means 2 is introduced into the residue incineration means (fluidized bed type combustion furnace) 3 together with the sand S and completely combusted by the blown air, 50 S of sand S is generated by the generated heat
Heat to 0-950 ° C. Part of the sand S is dechlorination means 1
Since the solid content in the waste plastic P is crushed to 100 to 200 mm or less, there is no trouble such as clogging, and the pretreatment is carried out. Only crushing is required and no special sorting is required.

[0012]

Therefore, according to the basic technique of the present applicant, the coking trouble in the thermal cracking means 2 can be avoided, long-term continuous operation can be achieved, the thermal cracking residue can be effectively used, and the high-quality low boiling point oil can be collected. Although it has become possible to improve the rate and simplify the separation of garbage, there are still the following problems.

That is, the plastics discharged from the municipal waste include PET, PVC, etc., and the gaseous thermal decomposition products thereof are 200 to 250 in the first gas-liquid separation means 4.
200 to 250 when countercurrently contacted with a low boiling point oil at a temperature of ℃
Terephthalic acid having a sublimation point at a temperature of ℃ or more (sublimation point of 300 ℃) and substances that are easily crystallized are also precipitated, and these precipitates, pyrolysis residue, crushed fragments of sand, etc. having an average particle size of about 10 microns The fine solids (dust) repeatedly return to the thermal decomposition means 2 through the packed bed in the first gas-liquid separation means 4, but the cycle is repeated indefinitely, so that the packed bed is sequentially formed. Captured and accumulated in filling materials,
In the worst case, there is a problem that the packed bed is clogged.

In order to solve such a technical problem, in Japanese Unexamined Patent Publication No. 9-20892, as shown in FIG. 4, the bottom part of the gas-liquid contact tank 125 is separated into two parts by a vertical partition plate 126, and the liquid is added to the top part of the furnace. A nozzle 128 is provided, and the light oil content is separated from the light oil storage chamber 135 separated by the vertical partition plate 126 via a cooler 130 to 250 to 300 ° C.
It is configured to be sprayed from a liquid nozzle 128 at the top of the furnace while being cooled. Below the liquid nozzle 128, the inclined plate 1
No. 27 is arranged, and the oil that has been brought into gas-liquid contact can first flow into the heavy oil storage chamber 132.

According to such a conventional technique, the gaseous thermal decomposition product having a temperature of, for example, about 400 to 450 ° C., which is fed from the thermal decomposition tank, is fed from the line 131 to the heavy oil storage chamber 132 of the gas-liquid contact tank. Be guided. In the heavy oil storage chamber 132, the low boiling point oil and the like evaporate due to the inflow of the temperature gas of about 400 to 450 ° C., but 250 from the liquid nozzle 128 at the furnace top.
Gas-liquid contact with light oil content cooled to a temperature of ~ 300 ° C,
Terephthalic acid or the like having a sublimation point at a temperature of 250 ° C. or higher is crystallized, and its precipitate or oil having a boiling point at 250 to 400 ° C. is returned to the heavy oil storage chamber 132. The light oil component in the upper layer of the heavy oil storage chamber 132 overflows the partition wall 126 and is stored in the light oil storage chamber 135. The above operation is repeated thereafter.

[0016]

In the prior art as described above, 400 to 450 is always provided in the heavy oil storage chamber from the thermal decomposition tank.
Since the gaseous pyrolysis products at around ℃ are supplied, the storage chamber inevitably becomes in a bubbling state, the convection phenomenon causes the precipitates to convection to the upper layer, and the light oil storage due to the overflow from the vertical partition wall. It has the drawback of moving to the room side.

Further, since the gaseous thermal decomposition product at about 400 to 450 ° C. is supplied, the heavy oil storage chamber is always kept at 40 ° C.
Since it is heated at around 0 to 450 ° C., the heavy oil component adheres to the wall surface of the storage chamber, and maintenance deterioration easily occurs.

In view of the above technical problems, the present invention aims to effectively remove precipitates and minute solids (dust) such as terephthalic acids, and to improve the quality and yield of low boiling point oil. It aims at providing the oil recovery device of.

[0019]

In order to solve such a problem, the present invention treats crushed waste plastic at a temperature of about 3 ° C.
Pyrolysis means for thermally decomposing at a temperature of 50 to 500 ° C. to obtain a pyrolysis gaseous product, and oil which is introduced into the gas-liquid contact space and jetted from above the gas-liquid contact space. To
By contacting the first to flow down the high-boiling oil separation means below
A gas-liquid contact means, the low-boiling oil recovery means for recovering low-boiling oil to cool the low boiling point component containing a low boiling point oil to said first gas-liquid contact means passing through the gaseous, the separating means in Of waste plastic that returns high boiling point oil stored in the tank to pyrolysis means
In the recovery device, the first gas-liquid contact means is placed at an intermediate position.
Has a packed bed in the bottom, and the bottom is directly inserted into the separating means.
It is composed of a packed column for precipitation, and the thermal decomposition is performed from below the packed bed.
Introduce a gaseous product and adjust cooling from the top of the packed bed
The oil that has been sprayed is sprayed, and by contact with the oil in the packed bed,
Crystallized substances containing terephthalic acid with high boiling point oil
The high boiling point oil and the crystallized substance are deposited at the bottom of the separating means.
We propose a waste plastic oil recovery device that can be separated by specific gravity . And preferably, the bottom of the separating means is
The diameter is reduced toward the side to form a tapered cone shape.
In addition, a packing layer is provided at an intermediate position of the first gas-liquid contacting means.
It is composed of a packed column for direct precipitation and is located below the packed column.
The lower end of the extended cylinder from above to the middle of the cone.
The thermal decomposition gas from below the packed bed.
A soot-like product was introduced, and cooling was adjusted from the top of the packed bed.
High-boiling oil is sprayed with oil, and the high boiling point oil is contacted with the oil in the packed bed.
At the same time, a crystallized substance containing terephthalic acid precipitates and spreads.
It flows down from the installation cylinder to the cone-shaped portion below the separating means,
High-boiling point oil and crystallized substance can be separated at the bottom of
Specifically, the cooling-adjusted oil is 300 ° C or higher.
Below, the high-boiling oil is an oil of approximately 250 to 350 ° C. or higher.
And the crystallized substance sublimates to a temperature of 250 ° C. or higher.
The crystallized substance containing terephthalic acid having points is
Good.

The gaseous thermal decomposition product is not directly introduced into the storage chamber of the solid-liquid separator as in the prior art, but
Since it is introduced into the gas-liquid contact space located above it, bubbling does not occur in the oil storage chamber of the solid-liquid separation device, and sedimentation separation based on the specific gravity difference between the precipitate and the high boiling point oil is performed accurately. You can Further, in the solid-liquid separation device, the heavy component sufficiently cooled (below 300 ° C.) drops due to the gas-liquid contact, in other words, the gaseous thermal decomposition production at about 400 to 450 ° C. shown in the above-mentioned prior art. Since it is not heated by the material, the heavy oil component can be easily discharged without adhering to the wall surface of the settling tank as the solid-liquid separation device or causing maintenance deterioration.

According to the present invention, between the thermal decomposition means and the first gas-liquid contacting means, the oil is cooled and adjusted to a temperature equal to or lower than the temperature of the thermal decomposition gaseous product, and the gas is decomposed with the thermal decomposition gaseous product. It is preferable to provide a reflux means for bringing into contact with the liquid and condensing heavy components such as tar and pitch in the product and returning them to the thermal decomposition means side.

According to this invention, since the heavy components such as tar and pitch in the pyrolyzed gaseous product are removed in advance, the first gas-liquid separation means is used to deposit the terephthalic acids. (1) There is no risk of these tars, pitches, etc. adhering to the wall surface in the gas-liquid separation means or the solid-liquid separation means,
Operation management can be performed easily without further maintenance deterioration.

Further, the present invention is characterized in that the high boiling point oil produced by the solid-liquid separation means is used as the gas-liquid contact oil of the first gas-liquid contact means or the reflux means. In this case, it is preferable to control the temperature by using a reflux cooler or the like in the circulation path.

Especially by using as the gas-liquid contact oil of the reflux means, the oil content can be always returned to the pyrolysis means side, and the conversion of the high-boiling oil to the low-boiling oil is further promoted. Moreover, since the high boiling point oil from which terephthalic acids have been separated and reduced is circulated and used as a coolant for the gaseous thermal decomposition products, accumulation and increase of terephthalic acid in the coolant does not occur, and the increase in the gaseous heat causes The clogging trouble in the gas-liquid contact means (packing tower etc.) that comes into contact with the decomposition products is also eliminated.

Further, according to the present invention, the high boiling point oil produced by the solid-liquid separation means is removed by distillation means to remove low boiling point components, and then returned to the thermal decomposition means, the first gas-liquid contact means or the reflux means. Is good.

That is, when the temperature at which the gaseous thermal decomposition product is contacted by the gas-liquid contacting means is low, the content of the low boiling point oil in the falling high boiling point oil increases, and it is directly used in the thermal decomposition means. When sent and reheated, the low boiling point oil is further thermally decomposed, the gas component increases, and the yield of the low boiling point oil may decrease. As a countermeasure, in the present invention, among the high boiling point oils obtained, those sent to the thermal decomposition means are distilled,
Since the low boiling point oil is configured to be recovered, it is not re-pyrolyzed, and the yield of the low boiling point oil is high even if the temperature at the time of contact with the gaseous pyrolysis products is low.

Further, in the present invention, the solid-liquid means is formed of a settling tank for performing solid-liquid separation by the difference in specific gravity, and
It is preferable that the liquid outflow opening of the first gas-liquid contacting device is made to enter the stored liquid in the settling tank. In the invention, the first
Since the gravitational energy at the time of liquid outflow of the gas-liquid contact means is reduced and the liquid outflow is performed gently, solid-liquid separation can be smoothly performed by the difference in specific gravity. In particular, the high-boiling point oil containing the fine solids separated by the first gas-liquid separation means is simply placed in, for example, a settling tank by the solid-liquid separation means, and the high-boiling point oil of liquid and terephthalic acid / fine solids Is separated by sedimentation. The terephthalic acids and minute solids are extracted and incinerated by, for example, a combustion furnace.

Further, in the present invention, a dechlorination means is provided in front of the thermal decomposition means, and HCl generated in the dechlorination step is used.
Both the rich gas, the crystallization substance stored in the bottom of the solid-liquid separation means, and the low boiling point gas generated by the low boiling point oil recovery means are supplied to the combustion furnace for supplying thermal energy to the thermal decomposition means and the dechlorination means. It is supplied and aims to circulate and utilize heat energy.

According to this invention, the heat energy can be efficiently used in the closed circuit, and the heat energy is not wasted.

Thus, according to the present invention, by contacting a hot pyrolysis gaseous product with a cold high boiling oil,
Condensing a high boiling point oil containing a precipitate and a fine solid content and separating it from a low boiling point component containing a low boiling point oil, separating a precipitate and a fine solid content from the obtained high boiling point oil, and a precipitate thereof And of the high boiling point oil from which the fine solids have been separated, the increased amount is heated to distill out the low boiling point component and then returned to the thermal decomposition means and thermally decomposed together with the waste plastic, but partly cooled, It can be recycled and reused for contacting hot pyrolysis gaseous products with cold high boiling oils.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. However, types of units and the like described in this embodiment, temperature, relative arrangement such as the arrangement order of the units, etc., are not intended to limit the scope of the present invention thereto only unless otherwise specified. It is only an example.

FIG. 1 is an overall system configuration diagram of a waste plastic oiling apparatus according to the basic configuration of the present invention. Next, embodiments of the present invention will be described in detail. First, the term “waste plastic” as used in the present invention refers to waste that is separated from municipal solid waste and mainly contains plastic, and mainly contains thermoplastic resins such as polyethylene, polypropylene, and polystyrene, and contains polyvinyl chloride (PVC), PETs, and the like. It means a thing, and may be mixed with a thermosetting resin, paper, and miscellaneous substances such as porridge. In addition, among industrial waste, polyvinyl chloride (PV
Those including C) and PETs are also included. The point is about 20
It refers to a material containing a plastic in which a solid substance having a specific gravity larger than that of oil is deposited by gas-liquid contact at 0 to 300 ° C.

The basic configuration of the present invention will be described below with reference to FIG. A crusher 30 crushes the solid content of the waste plastic P to 100 to 200 mm, and then throws it into the rotary kiln 1 for dechlorination. In the rotary kiln 1, the waste plastic P and 400 to 950 ° C.
The waste plastic P is heated to a temperature of 250 to 350 ° C. while the circulating sand S heated at a high temperature is extruded and mixed.

As a result, about 95% or more of the chlorine in the waste plastic P is separated, and the gas containing HCl as the main component is taken out from the HCl-rich gas extraction line 53 provided in the upper part of the kiln 1, and the fluidized bed furnace 3 and the heat recovery unit are taken out. 60, bag filter 61
The water is recovered as water or an alkali absorption liquid by the HCl absorption tower 62 via the. Then, the mixture of the circulating sand S and the dechlorinated plastic P is supplied to the thermal decomposition tank 2 through an extraction line 9 composed of a screw conveyor or the like.

According to the rotary kiln 1, since the high temperature sand S is directly heated, the heat transfer area is large as the surface area of the sand S and the waste plastic P can be easily heated.

The thermal decomposition tank 2 is composed of a stirring tank capable of uniformly mixing the sand S, the additive T, and the waste plastic P. The additive T supplied from the additive supply line 10 and the circulating sand supply line 11 are supplied. Further, the high-temperature circulating sand S of 500 to 950 ° C. is mixed with the plastic P mixture supplied from the extraction line 9, and the thermal decomposition is performed while maintaining the temperature at 400 to 480 ° C. As the additive T, synthetic zeolite or natural zeolite, preferably natural mordenite is used.

Then, the solid thermal decomposition residue (carbonaceous material) generated in the thermal decomposition tank 2, solid foreign matter, and the non-liquefied thermosetting resin are taken out from the thermal decomposition residue mixture extraction line 17 with a screw feeder or the like. , The fluidized bed combustion furnace 3.

A reflux tower 4 is connected above the pyrolysis tank 2, and the pyrolysis product gas produced from the pyrolysis tank 2 in the reflux tower 4 and a nozzle 42 provided at the top of the furnace are jetted. The heavy components such as tar and wax are returned to the thermal decomposition tank 2 by gravity by gas-liquid contact or gas-air contact with oil cooled and adjusted to a temperature lower than the temperature of the thermal decomposition gaseous product. still,
The oil ejected from the nozzle 42 is configured so that the recovered oil produced in the fractionating tower 5 is temperature-controlled and supplied to the nozzle 42, but the present invention is not limited to this, and the supernatant oil of the sedimentation tank 6 described later is used. May be supplied to the nozzle 42.

Then, the pyrolysis product gas from which the heavy components have been removed is fed to the gas-liquid contact space 59 of the deposition tower 50 (see FIG. 2). The deposition packed tower 50 is provided with a liquid nozzle portion 57 above the packed bed 58, has a lower opening extending cylindrically downward, and allows the lower end opening of the extending cylinder 40 to penetrate into the liquid of the settling tank 6. The inlet 49 for the pyrolysis product gas is shown in FIG.
As shown in FIG. 5, the inlet 49 may be set in the middle of the filling layer 58 or below the filling layer 58, both of which serve as a gas-liquid contact space.

The oil ejected from the liquid nozzle portion 57 is recovered oil produced in the fractionating tower 5, which is cooled by a cooler 45 to 200 to 300 ° C., preferably 250 to 300 ° C. Although it is configured to be supplied to the section 57,
The present invention is not limited to this, and the supernatant oil of the settling tank 6 may be supplied to the nozzle portion 57 as shown in FIG. As a result, terephthalic acid having a sublimation point at a temperature of 250 ° C. or higher comes into gas-liquid contact with the recovered oil cooled to a temperature of 250 to 300 ° C. from the liquid nozzle portion 57 and the pyrolysis gas from which heavy components have been removed. Etc. are crystallized and, together with the precipitate, 250 to 4
The high boiling point oil having a boiling point at 00 ° C. falls into the extension cylinder 40 and enters the liquid in the settling tank 6 through the lower end opening of the extension cylinder 40.

The high-boiling point oil having a boiling point of 250 to 400 ° C. and the crystallized terephthalic acid are separated by specific gravity in the settling tank 6, and the terephthalic acid (specific gravity of about 1.5) is at the bottom of the high-boiling point oil ( (Specific gravity around 0.85) is stored in the upper part as a supernatant oil. The terephthalic acid or the like stored in the bottom of the settling tank 6 is supplied to the fluidized bed combustion furnace 3 as a fuel. And the high boiling point oil as the supernatant oil is line 47
After being led to the bottom of the fractionating tower 5 via a condenser, after evaporating the low boiling point component by a distiller 52 consisting of a heater, the residual high boiling point oil is jetted from the nozzle section 42 into the reflux tower 4 , And returns to the thermal decomposition tank 2 for circulation along with the heavy components that have come into gas-liquid contact.
By returning the high boiling point oil to the thermal decomposition tank 2 through the line and the reflux tower 4 in this manner, the high boiling point oil and the heavy component are repeatedly heated in the thermal decomposition tank 2 and are further decomposed. It becomes a low boiling point oil, the yield of low boiling point oil increases, and the quality and storage stability of oil are improved. Further, a part of the high boiling point oil is guided to the liquid nozzle portion 57 of the precipitation packed tower 50.

On the other hand, the low molecular gas and gaseous low boiling point oil (about boiling point 250 ° C. or less) which is not liquefied in the deposition packed tower 50 is introduced into the fractionating tower 5 and then heated to about 30 ° C. by the cooler 51. The low-boiling oil O is cooled to obtain the low-boiling oil O, which is recovered from the fractionating section of the fractionating tower 5 and the uncondensed low-molecular gas is sent to the combustion furnace 3 through the low-molecular gas extraction line 16.

The combustion furnace 3 is composed of a high-speed circulating fluidized bed or a bubbling fluidized bed. Air is introduced from the combustion air supply line 18 to form a fluidized bed using sand S as a medium, and the temperature is 500 to 950 ° C. Preferably, the temperature is maintained at 750 to 950 ° C., the organic substances in the line 17 are completely combusted, and the exhaust gas is further heated to 850 to 950 ° C. by introducing the secondary air A to suppress the generation of dioxins and the like, while burning. Combustion exhaust gas G is taken out from the exhaust gas extraction line 21, heat is recovered by a heat exchanger 60, and ash is removed by a bag filter 6
1. Exhaust gas treatment such as hydrogen chloride removal 62 by acid or alkali absorption is performed.

On the other hand, the incombustible material F such as metal or glass which has not been completely incinerated in the combustion furnace 3 is taken out from the incombustible material extraction line 19. A part of the sand S in the fluidized bed heated to 750 to 950 ° C. is recycled from the sand removal lines 20, 11 and 7 to the dechlorination kiln 1 and the pyrolysis furnace 2. While the waste plastic P supplied from the waste plastic supply line 110 and the sand S heated to a high temperature of 400 to 950 ° C. are mixed in the dechlorination means 1 (for example, a rotary kiln) and sent from one end to the other end. Then, the waste plastic P receives heat from the sand S and is heated to a temperature of 250 to 350 ° C.

FIG. 2 shows an embodiment of the present invention. The pyrolysis gaseous product gas produced in the pyrolysis tank 2 is directly introduced into the gas-liquid contact space 59 of the deposition tower 50 without passing through the reflux tower 4. ing. Explaining in detail, first, the packed column for precipitation 50
Then, the pyrolysis gaseous product gas of high temperature (around 450 ° C.), which is supplied into the gas-liquid contact space 59 below the packed bed 58 and rises, is the supernatant oil of the sedimentation tank 6 from above by the liquid dispersion nozzle 57. The boiling point oil is sprayed after being cooled by the cooler 45 to 300 ° C. or lower, for example, 250 to 300 ° C. That is, by the spraying, the pyrolysis gaseous product around 450 ° C. is countercurrently contacted with the descending low temperature high boiling point oil to be cooled,
For example, medium-heavy oil having a boiling point of 250 ° C. or higher, which is contained in the pyrolysis gaseous product, is condensed, and terephthalic acids are precipitated, and both are washed and captured by the low-temperature high-boiling oil that flows down together with the fine solids. , Is separated from the low boiling point component of the gaseous pyrolysis product gas at 250 ° C or lower.

The lower part of the settling tank 6 is formed in a cone shape, and is arranged so as to be able to receive the condensed oil and the terephthalic acid falling from the packed tower 50. The terephthalic acid precipitates / fine solids are precipitated from the high boiling point oil that has flowed into the settling tank 6 from the lower end of the extension cylinder 40 of the precipitation column 50, collected at the cone-shaped bottom, and drained by the drain 43. It is discharged and processed as fuel for the combustion furnace 3, for example. If a sedimentation separation method that uses centrifugal force rather than gravity is adopted, the separation speed and degree of separation of solids will increase.

Supernatant liquid storage section of settling tank 6 and deposition packed tower 5
A cooler 45 is provided along with a pump 44a in a line 44 that connects the liquid nozzle portion 57 at the 0 top.
The high boiling point oil having a reduced solid content such as terephthalic acid precipitates cooled by the cooler 45 is deposited and packed in the tower 50.
It is supplied to the liquid dispersion nozzle portion 57 at the top of and is sprayed by the liquid dispersion nozzle 57.

Further, the supernatant liquid in the settling tank 6 is stored in the line 4
7 and the pump 47a to the bottom of the fractionating tower 5,
Further, a line 24 is provided between the bottom of the fractionating tower 5 and the thermal decomposition tank 2.
And an oil circulation line by the pump 24a is provided, and after the low boiling point oil O is distilled out by a distiller (heater) 52 attached to the bottom of the fractionating tower 5, the high boiling point oil at high temperature enters the thermal decomposition tank 2. It is returned and undergoes re-pyrolysis.

Summarizing the operation of this embodiment,
First, in the packed column 50 for precipitation, the gaseous pyrolysis product gas comes into contact with a high boiling point oil having a temperature of 300 ° C. or lower, which is a coolant,
When cooled, the high boiling point oil in the produced gas is condensed, terephthalic acids are precipitated (when the temperature is 300 ° C. or less), and both are washed and captured by the low temperature high boiling point oil flowing down together with the fine solid matter. It is separated from low-boiling components and falls.

The high boiling point oil containing the dropped terephthalic acids / fine solids is simply placed in, for example, the settling tank 6, and due to the difference in specific gravity, it becomes liquid high boiling point oil and terephthalic acids / fine solids ( Sedimentation) separated. In addition, terephthalic acids and minute solids are extracted, for example, in the combustion furnace 3
Is incinerated by.

When the temperature at the time of contacting the gaseous pyrolysis product in the deposition packed tower 50 is low, terephthalic acids are completely precipitated and are washed and captured by the descending liquid, so that they are completely removed from the low boiling point components, It will not be deposited on the inner surface of the subsequent pipeline, etc., and will not cause a blocking trouble. Moreover, since the high boiling point oil with reduced terephthalic acids is circulated and used as a coolant for the gaseous pyrolysis product gas, accumulation and increase of terephthalic acid in the coolant does not occur, and the increase causes a gaseous heat release. The clogging trouble in the first gas-liquid contacting means such as the packed tower 50 that comes into contact with the decomposition products is also eliminated.

However, when the temperature at the time of contacting the gaseous pyrolysis product in the packed tower 50 is low, the content of the low boiling point oil in the falling high boiling point oil increases, and it is sent to the pyrolysis means 2 as it is. When reheated, the low boiling point oil is further thermally decomposed, the gas component increases, and the yield of the low boiling point oil may decrease. However, in the present invention, among the obtained high boiling point oils, the ones sent to the thermal decomposition tank 2 are once distilled in the distiller 52 in the fractionation tower 5 to recover the low boiling point oil O. Therefore, it is not re-pyrolyzed, and the yield of low boiling point oil is high even when the temperature at the time of contacting the gaseous pyrolysis product is low.

In addition, on the gas outlet side of the precipitation packed tower 50, a second gas-liquid separating means 5 is connected in series via an uncondensed gas extraction line 48, and the precipitation packed tower 50 to the fractionating tower 5 are connected in series. To about 3 by the cooler 51 inside.
The low boiling point oil O cooled to 0 ° C. is discharged, and further the low molecular gas is sent to the combustion furnace 3 through the low molecular gas extraction line 16. Further, it is preferable that the distiller 52 is integrated with the fractionating tower 5, but both may be installed independently.

[0054]

As described above, according to the invention of claim 1, the gas is introduced not into the storage chamber of the solid-liquid separation device but into the gas-liquid contact space located above the storage chamber. Bubbling does not occur in the oil storage chamber of the solid-liquid separation device, and sedimentation separation based on the difference in specific gravity between the precipitate and the high boiling point oil can be performed accurately. Further, the heavy oil component can be easily discharged without adhering to the wall surface of the settling tank as a solid-liquid separation device or causing maintenance deterioration.

According to the present invention, the heavy components such as tar and pitch in the pyrolyzed gaseous product are removed in advance, and then the first gas-liquid separation means is used to deposit terephthalic acids. (1) There is no fear that these tars, pitches, etc. will adhere to the wall surface in the gas-liquid separation means or the solid-liquid separation means, and the operation and management can be easily performed without further deterioration of maintenance.

Further, in the present invention, by using the high boiling point oil produced by the solid-liquid separation means as the gas-liquid contact oil of the reflux means, the oil content can be always returned to the pyrolysis means side,
The conversion of high boiling oil to low boiling oil is further promoted. Moreover, since the high boiling point oil from which terephthalic acids have been separated and reduced is circulated and used as a coolant for the gaseous thermal decomposition products, accumulation and increase of terephthalic acid in the coolant does not occur, and the increase in the gaseous heat causes The clogging trouble in the gas-liquid contact means (packing tower etc.) that comes into contact with the decomposition products is also eliminated.

Further, in the present invention, among the obtained high boiling point oils, the ones sent to the thermal decomposition means are distilled and the low boiling point oils are recovered, so that they are re-thermally decomposed. Nonetheless, the yield of low boiling point oil is high even when the temperature at the time of contacting the gaseous pyrolysis products is low.

Further, according to the present invention, the gravity energy at the time of liquid outflow of the first gas-liquid contact means is reduced, and the liquid outflow is performed gently, so that the solid-liquid separation can be smoothly performed by the difference in specific gravity. .

Further, according to the present invention, the heat energy can be efficiently used in the closed circuit, and the heat energy is not wasted.

[Brief description of drawings]

FIG. 1 is an overall device configuration diagram showing an oil recovery device from waste plastic in which the basic configuration of the present invention is incorporated.

FIG. 2 is a configuration diagram of a main part of a device showing an oil recovery device from waste plastic, in which an embodiment of the present invention is incorporated.

FIG. 3 is an overall device configuration diagram showing a waste plastic oil recovery device according to a conventional technique.

FIG. 4 is a configuration diagram of a main part of the related art for producing terephthalic acid or the like which is a thermally decomposed gaseous product.

[Explanation of symbols]

1 Dechlorination means (rotary kiln) 2 Pyrolysis means 3 fluidized bed combustion furnace 4 reflux tower 5 fractionation tower 50 Precipitation packed tower 40 extended cylinder 6 Solid-liquid separation means 45, 51 cooler 52 Distiller 23 Low temperature and high boiling point oil circulation means 24 High temperature and high boiling point oil circulation means 42,57 Liquid Disperser C cooler F incombustibles O low boiling point oil P Waste plastic S sand

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Kaihara 12 Nishiki-cho, Naka-ku, Yokohama-shi In Mitsubishi Heavy Industries, Ltd. Yokohama Works (72) Kenichi Yoneda 12 Nishiki-machi, Naka-ku, Yokohama-shi In Mitsubishi Heavy Industries, Ltd. 72) Inventor Shigehiro Sato 12 Nishiki-cho, Naka-ku, Yokohama City Mitsubishi Heavy Industries, Ltd. Yokohama Works (56) Reference JP-A-9-20892 (JP, A) JP-A-7-216364 (JP, A) JP Flat 9-235562 (JP, A) Actual development Sho 58-140155 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C10G 1/10 C10B 53/00

Claims (4)

(57) [Claims] 1.Crushed waste plasticThe temperature is about 35
Pyrolysis at a temperature of 0 to 500 ° C produces a pyrolyzed gaseous product.
Thermal decomposition means to obtain, Introduce the pyrolyzed gaseous product into the gas-liquid contact spaceGas-liquid
The high boiling point oil is brought into contact with the oil jetted from above the contact space.
DownwardMinutes ofFirst gas-liquid contacting means for flowing down to the separating means, The low boiling point oil which has passed through the first gas-liquid contact means in a gaseous state is
A low boiling point oil that recovers a low boiling point oil by cooling the low boiling point component that contains
Collection means,Said separation The high boiling point oil stored in the means is returned to the pyrolysis means.
YouIn a waste plastic oil recovery device, The first gas-liquid contact means has a packing layer at an intermediate position, and the bottom
The part Inserted in the meansConsists of a packed column for direct precipitation
Then, the pyrolysis gaseous product is introduced from below the packed bed.
Spray the conditioned oil from the top of the packed bed.
The high boiling point oil by contact with the oil in the packed bed
The crystallization substance containing terephthalic acid precipitates,
High-boiling oil and crystallized substance can be separated by specific gravity at the bottom of the stage
Oil recovery equipment for used plastic waste. 2. The method according to claim 1.Oil recovery from waste plastic
In the device, The bottom portion of the separating means is reduced in diameter toward the bottom side to form a tapered core.
And the first gas-liquid contacting means
It is composed of a packed column for direct precipitation having a packed bed at an intermediate position,
The lower end of the extending cylinder located below the packed tower is provided with the cone-shaped portion.
In addition to hanging from the upper part to the middle position, the filling layer
The pyrolysis gaseous product was introduced from below the
Disperse the chilled oil from the upper part,
Includes terephthalic acid with high boiling oil upon contact with
Cone below the separating means from the extension cylinder where the crystallized substance precipitates
And then crystallized with high boiling oil at the bottom of the cone
Oil recovery from waste plastics whose substances can be separated by specific gravity
apparatus. 3. The cooled conditioned oil is below 300.degree.
Yes, the high boiling point oil is an oil having a temperature of approximately 250 to 350 ° C. or higher.
The crystallization substance has a sublimation point above 250 ° C.
2. A crystallization substance containing terephthalic acid having
Alternatively, the waste plastic oil recovery device described in 2 . 4. The method of claim 1, 2 young, characterized in that for use as a gas-liquid contact fluid in the first gas-liquid contact means directly cooled by the cooler high boiling oil is gravity separated by the separating means
The waste plastic oil recovery device described in item 3 .