JP3393967B2 - Method and apparatus for treating plastic waste - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating plastic waste, and more particularly to a method for recovering oil or the like by thermally decomposing plastic waste containing a halogen-based polymer mixed with a plasticizer. The present invention relates to a resource recovery processing method and an apparatus thereof.

[0002]

2. Description of the Related Art In recent years, the amount of plastic waste that needs to be processed has been increasing more and more, and there is a demand for early establishment of a recycling technology. Conventionally, various methods have been proposed for producing fuel oil by dry distillation and thermal decomposition of plastic, but the target plastics are limited to polyolefins such as polyethylene and polypropylene, and polystyrene. Technological development also flourished temporarily due to the oil shock, but it has been forced to suspend due to the subsequent drop in oil prices. In addition, at the time when it was easy to secure landfill disposal sites, there was little need to actively promote recycling, and landfill sites were often used in view of low treatment costs. In addition, since plastic has a higher calorific value than wood and paper, it is burned as it is in a refuse incinerator,
In many cases, the combustion heat is utilized for various heat applications.

Recently, however, the suppression of the amount of carbon dioxide released to the global environment, which is the main causative agent of the greenhouse effect,
Measures such as prevention of air pollution caused by the release of harmful substances are strongly required not only in Japan but also abroad, and from the viewpoint of utilizing limited global resources, development of waste utilization technology is indispensable. As a result, the technology of recycling (recycling) plastic waste is in the limelight again.

In order to expand the conversion (oilification) of a plastic into an oily substance by dry distillation / pyrolysis to a thermoplastic resin other than a polyolefin, such as polyvinyl chloride,
It is unavoidable to apply to plastics that generate harmful gases such as hydrogen chloride gas when heated, but even when plastics are incinerated as garbage, the concentration of hydrogen chloride increases as the amount of polyvinyl chloride increases. Therefore, it is necessary to consider the corrosion resistance of the combustion treatment (incineration) device, and the cost for imparting corrosion resistance to the device tends to increase as the amount of treatment increases. Further, although a combustion treatment device to which a system for separating polyvinyl chloride and the like is added has been developed, this system inevitably costs too much.

[0005]

The necessity and difficulty of the recycling treatment of polyvinyl chloride will be described in more detail below.

[0006] Japan is one of the world's leading producers of plastics, in particular, the production of polyvinyl chloride is extremely large (the second largest in the world after the United States), and the amount discarded in Japan is also large.
It accounts for about 16% of all plastics, and a large proportion together with polyolefin-based thermoplastics.

Generally, the plasticizer has a function of weakening the intermolecular force of the plastic or rubber to lower the glass transition temperature, and the fluidity, flexibility, extensibility, elasticity, adhesiveness, processability of the plastic or rubber, etc. Polyvinyl chloride, which is added for the purpose of improving plasticity, is roughly classified into soft polyvinyl chloride containing such a plasticizer and hard polyvinyl chloride containing no plasticizer. Looking at the production record of soft polyvinyl chloride, we found that
Leather, hoses, machinery parts, home appliances components,
It is used for daily necessities and miscellaneous goods, and is indispensable for daily life. Polyvinyl chloride plasticizers include phthalic acid-based, fatty acid-based, phosphoric acid-based, adipic acid-based, polyester-based, epoxy-based plasticizers,
Among these, DOP (dioctyl phthalate), DB
P (dibutyl phthalate), DHP (diheptyl phthalate), DIDP (diisodecyl phthalate), DINP
Phthalic acid-based plasticizers such as (diisononyl phthalate) are mainly used, and the use of DOP accounts for about 50% of the total. And, it is not preferable in terms of the global environment to dispose of phthalic acid plasticizers such as DOP as they are, and there are some substances whose effects on the ecosystem are not known. In addition, the present situation is that an alternative substance to replace such a plasticizer has not yet been developed and an effective recovery and reuse method has not been established.

Regarding the necessity of volume reduction treatment of plastic waste and the limit of heat remolding treatment, since plastic waste is bulky, when it is transported and collected as garbage, the transportation weight per time is easily increased. This was not possible, and this bulkiness also accelerated the sudden shortage of landfill sites. Therefore, conventionally, there is known a method in which plastic waste is softened / compressed by heating to reduce the volume, and the volume-reduced solid material is reprocessed and used. For polyvinyl chloride and the like, which may generate harmful gas at times, it is necessary to perform heat treatment at a limited temperature, and there has been a demand for expanding the application of treatment technology.

Further, comparing both the case where the regenerated product from the plastic waste is obtained as a liquid and the case where it is obtained as a solid, the case where it is obtained as a liquid has the advantage that it can be easily obtained continuously from the thermal decomposition process. On the other hand, comparing both the case of obtaining with a liquid and the case of obtaining with a gas, the case of obtaining with a gas has the advantage that it is easy to adjust the mixing with air in the combustion process, but in a limited space in the long term. When storing and transporting, it is more preferable to obtain it as a liquid. From these points,
It is required to obtain recycled resources from plastic waste as a liquid that is easy to handle at room temperature.

Further, the following can be said as to the necessity of separating harmful gas generated by thermal decomposition of polyvinyl chloride. That is, when gradually heating polyvinyl chloride from room temperature, chlorine bound to the α-position of carbon in the main chain and hydrogen bound to the β-position begin to desorb at around 300 ° C, and most of the It recombines to become a gas component (hydrogen chloride) and leave the polymer. When hydrogen chloride is generated in this way, if moisture remains in the device, its corrosion will increase rapidly.Therefore, it is necessary to use a material with high corrosion resistance as a component of the device. Since the area of the portion to be used also becomes large, it is necessary to suppress the use of the corrosion resistant material as much as possible and reduce the cost.
Thus, the generation of hydrogen chloride due to desorption during thermal decomposition
Locally limited termination is essential to significantly reduce the use of corrosion resistant materials. Further, it is not preferable to release the generated hydrogen chloride into the atmosphere as it is because it pollutes the atmosphere, and thus, in the thermal decomposition of polyvinyl chloride, conventionally, the generated hydrogen chloride has to be treated with an alkali such as a calcium salt. Although a method of reconstitution has been attempted, if hydrogen chloride with high purity can be separated and recovered, the possibility of reuse increases and it is also useful from the viewpoint of effective utilization of resources.

Further, in the thermal decomposition of polyvinyl chloride containing a plasticizer, heating from room temperature to 250 ° C.
At around 350 ° C, phthalic acid-based compounds are generated in addition to hydrogen chloride due to decomposition of the plasticizer. Among such phthalic acid-based compounds, phthalic anhydride is particularly desired to be separated from phthalic anhydride and other organic components because if cooled after being gasified, it blocks pipes that come into contact with the flow path.

Furthermore, if a large amount of hydrogen chloride and the decomposition product of the plasticizer are allowed to coexist at a high temperature, an organic chlorine compound may be produced. In recent years, this organic chlorine compound has been regarded as a problem from the viewpoint of environmental pollution, and together with the detection example of dioxins in garbage incinerators, hydrogen chloride desorbed from polyvinyl chloride and decomposition products such as plasticizers are generated. There has been a demand for a treatment method in which certain hydrocarbons do not coexist as much as possible.

The present invention has been made in view of these circumstances, and in the case of thermally decomposing wastes such as polyvinyl chloride containing a plasticizer to produce and recover oil (oil conversion), an organic chlorine compound of It is an object of the present invention to provide a method and a treatment device for recycling plastic waste, which can suppress the generation of oil, obtain a high-quality oil containing almost no chlorine, can easily prevent the equipment from corrosion, and do not require facility cost. To do.

[0014]

In order to solve the above-mentioned problems, the inventors of the present invention have conducted extensive studies, and as a result, by heating polyvinyl chloride containing a plasticizer while controlling the temperature, It has been found that the desorption of hydrogen chloride and the decomposition of the plasticizer can be carried out efficiently at the same time, the generation of organic chlorine compounds can be suppressed, and a high-quality oil having a small chlorine content and a uniform molecular weight distribution can be recovered. In addition, the generated gas is retained in a closed reaction tank and the pressure in the tank is increased to decompose the plasticizer and dehydrochlorinate, thereby shortening the decomposition time and reducing the proportion of light components in the recovered oil. The present invention has been completed based on the finding that it can be increased.

The first aspect of the present invention is directed to a method for treating plastic waste, which comprises heating a plastic waste containing a halogen-containing polymer blended with a plasticizer while pressurizing the generated gas and controlling the temperature, A thermal decomposition step of decomposing the plasticizer to separate the decomposition products and desorbing the halogen compound gas; and an oil conversion step of dry distillation and thermal decomposition of the residue of the thermal decomposition step to produce and recover oil. It is characterized by having.

Further, the apparatus for treating plastic waste according to the present invention comprises a feeder for continuously feeding the plastic waste and a feed moving mechanism, and heats the plastic waste continuously fed by the feeder. Then, the heating temperature of the heating reaction device that decomposes the plasticizer and desorbs hydrogen chloride and the heating temperature of the heating reaction device are controlled so as to reach a predetermined temperature at each position along the axial direction of the feed movement mechanism. A heating control device, a thermal decomposition device for dry distillation / pyrolysis of the residue from the heating reaction device to generate a polymer decomposition gas, and a cooling condenser for cooling and condensing the polymer decomposition gas generated in the heating decomposition device It is characterized by comprising and.

The second processing apparatus of the present invention comprises a stirrer, a heating reaction tank for heating plastic waste to decompose the plasticizer and desorb hydrogen chloride, and a heating reaction tank in the heating reaction tank. A heating control device for controlling the heating temperature, a pressure control valve for maintaining the pressure inside the heating reaction tank at a set pressure, and a polymer decomposition gas by dry distillation and thermal decomposition of the residue from the heating reaction device. And a cooling condenser for cooling and condensing the polymer decomposition gas generated in the heat decomposition apparatus.

Examples of halogen-based polymers in the present invention include chlorine-based polymers.
As the chlorine-based polymer, not only polyvinyl chloride (vinyl chloride resin), which is a vinyl chloride homopolymer or a vinyl chloride-based copolymer, but also polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymer, chlorine Includes all polymeric substances that generate hydrogen chloride by thermal decomposition, such as chlorinated polyethylene.

In the method for treating plastic waste of the present invention, a plastic waste containing a halogen-based polymer such as a chlorine-based polymer blended with a plasticizer is heated at atmospheric pressure while controlling the temperature to remove chloride. It promotes desorption of halogen compound gas such as hydrogen, and decomposes the plasticizer by the generated halogen compound gas to decompose efficiently at a lower temperature than when the plasticizer is decomposed alone, and then dry distillation / pyrolysis. It was confirmed by the following experiment that high-quality oil containing almost no halogen can be recovered by carrying out the oil production and recovery (oilification). Further, by desorbing halogen compound gas such as hydrogen chloride and decomposing the plasticizer while pressurizing with the generated gas, these reactions can be carried out more efficiently and higher quality oil can be produced and recovered. I was also able to confirm that As described above, as the plasticizer for polyvinyl chloride, DOP, DBP, DH
Phthalates plasticizers such as P and DIDP are mainly used. Among them, DOP is the most compounded in terms of compatibility with polyvinyl chloride, so DOP was used as a plasticizer. I tried an experiment.

First, when a small amount of DOP is put into a flask and heated, the liquid substance decomposes and evaporates at a heating temperature of 300 ° C. to 350 ° C., and the generated decomposition gas is rapidly cooled. Acid crystals deposit and adhere to the inner surface of the cooling pipe. On the other hand, when polyvinyl chloride containing no plasticizer is put into the flask and heated, the temperature rises from 270 ℃ to 35 ℃.
It was observed that a gas containing a large amount of hydrogen chloride was generated at 0 ° C, and a black carbonized residue adhered to the flask.

Therefore, as a simulation experiment, 50 parts by weight of polyvinyl chloride (hereinafter referred to as "part") and 50 parts of DOP are used as materials having a composition similar to that of soft polyvinyl chloride actually used in home electric appliances and daily necessities. A mixed sample was prepared, and a small amount of this sample was put in a flask and heated by a heater to try to analyze the generated gas. At this time, chain organic compounds such as 2-ethylhexane, 2-ethylhexanol, and 2-ethylhexanal, which are decomposition products of DOP, are generated as a gas from 250 ° C to 300 ° C to generate an aromatic ring. It was confirmed that the phthalic anhydride contained therein was deposited as a crystalline substance in the cooling pipe. As the inside of the flask was further heated, small bubbles were observed to be actively generated from the surface of the sample from 300 ° C to 350 ° C. The generated gas was collected and analyzed and found to contain a large amount of hydrogen chloride. It was confirmed. A black deposit remained in the flask when gas evolution had ceased.

Further, the same sample was put in a metallic closed reaction vessel and heated by a heater to try to analyze the generated gas. At this time, the pressure inside the reaction vessel starts to rise from 250 ° C, and at 280 ° C the specified pressure is 4 kgf / cm ² (gauge pressure).
And the gas was released from the pressure control valve. When the gas released at this time was cooled and condensed to examine its components,
It was found to be a chain organic compound such as 2-ethylhexane, 2-ethylhexanol, and 2-ethylhexanal, which are decomposition products of. Further, it was confirmed that phthalic anhydride having an aromatic ring sublimated and was deposited as a crystalline substance in the cooling tube. When the inside of the reaction vessel is further heated, 2
It was confirmed that the pressure increased remarkably from around 90 ° C, and when the temperature reached 300 ° C, the opening of the pressure regulating valve became maximum and the gas was released. When this gas was collected and held over litmus paper moistened with purified water, it instantly turned red and had an irritating odor. Further, when a small amount of gas was diluted and analyzed by gas chromatography, it was found to contain a large amount of chlorine. When the generation of gas decreased and reached 350 ° C, heating was stopped, and when cooling was performed to confirm the internal residue, a black deposit remained in the container.

From these experiments, polyvinyl chloride and DO
In the mixed system (composition) with P, the decomposition of the plasticizer and the desorption reaction of hydrogen chloride proceed in parallel by heating, and the polyvinyl chloride containing the plasticizer is controlled while controlling the temperature or pressure and pressure. It was found that by heating while controlling and, it is possible to separate into a component containing a large amount of hydrogen chloride and a component containing almost no hydrogen chloride. Therefore, high-quality oil having an extremely low chlorine content can be produced and recovered by dry distillation and thermal decomposition of the thus obtained component containing almost no hydrogen chloride. In particular, when the plasticizer is decomposed and dehydrochlorinated while being pressurized to a predetermined pressure, the heating is terminated after reaching a predetermined temperature, as compared with the case where the plasticizer is pyrolyzed at a normal pressure. It takes about 1/2 to 2/3 to complete the process.

In the method for treating plastic waste of the present invention, the pressure conditions for decomposing the plasticizer and desorbing halogen compounds such as hydrogen chloride are 0 to 100 kgf / gauge pressure.
The pressure is set to cm ² , more preferably 0 to 10 kgf / cm ^2, and heating is performed under such pressure at a temperature of 200 to 450 ° C, more preferably 250 to 350 ° C.

Further, in the method for treating plastic waste of the present invention, after the decomposition of the plasticizer and the desorption of the halogen compound gas such as hydrogen chloride are carried out in parallel,
By adding an alkali to the residue and neutralizing a trace amount of the remaining halogen compound and then performing oiling, it is possible to produce and recover a high-quality oil having a smaller halogen content.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to Examples.

FIG. 1 is a diagram showing a schematic construction of an embodiment of an apparatus used in the method for treating plastic waste of the present invention.

As shown in the figure, the processing apparatus of the embodiment comprises a feeder 1 for continuously supplying a fixed amount of plastic waste at a fixed time, and a plastic waste continuously fed from the feeder 1. Heat reaction device 2 that receives and thermally decomposes
A heating control device 3 for controlling the heating temperature of the heating reaction device 2 to be a predetermined temperature at each position along the length direction of the device (flow direction of plastic waste); It is provided with a thermal decomposition tank 4 that receives the residue and further thermally decomposes it, and a cooling condenser 5 that cools and condenses the polymer decomposition gas (oil component gas) generated in the thermal decomposition tank 4.

As shown in an enlarged scale in FIG. 2, the heating reaction device 2 is provided with a feed moving mechanism 6 in which a feed blade 6b is spirally provided around a shaft 6a. By rotating the moving mechanism 6 around the shaft 6a by the motor 7 or the like, the supplied plastic waste is continuously moved between the inner wall of the cylinder 8 of the heating reactor 2 and the shaft 6a. There is. Further, the heating reaction device 2 is provided with a nitrogen gas injecting device 9. By injecting the nitrogen gas into the cylinder 8 by this injecting device 9 and constantly blowing a small amount of nitrogen gas, the oxygen in the cylinder 8 is It is configured to perform purging and cleaning. Further, on the upper part of the heating reaction device 2, a gas withdrawing pipe 10 for withdrawing gas generated during decomposition of plastic waste to the outside without accumulating in the cylinder 8 is provided along the length direction of the cylinder 8. It is provided and communicates with the inside of the cylinder 8 through a plurality of gas discharge ports 11 provided at regular intervals. Then, the decomposed gas is taken out from the gas drawing pipe 10 and the components are analyzed. Furthermore, the thermal decomposition tank 4 is provided with an alkali injection device 12 and an agitator 13, respectively.
The rotary shaft of the feed moving mechanism 6 may be of a biaxial type as well as a uniaxial type. Further, reference numeral 14 in FIG. 1 indicates a residue recovery tank, and 15 indicates an oil recovery tank.
Further, reference numeral 16 in FIG. 2 indicates a heater provided in the heating reaction device 2.

Another embodiment of the apparatus for treating plastic waste used in the present invention is shown in FIGS. 3 to 7, respectively.
In these figures, the same parts as those in FIGS. 1 and 2 are designated by the same reference numerals, and the description thereof will be omitted.

In the processing apparatus shown in FIGS. 3 and 4, the heating reaction apparatus 2 also serves as a heating decomposition tank, and the decomposition of the polymer is performed in the heating reaction apparatus 2. That is, the temperature in the cylinder 8 of the heating reactor 2 is between the predetermined position slightly upstream from the center in the longitudinal direction and the supply port (upstream side), and dehydrochlorination of the plastic waste and decomposition of the plasticizer. And is controlled so that the polymer is decomposed between the position and the end portion (downstream side). An alkali injecting device 12 is provided at the starting end of the polymer decomposing portion of the cylinder 8. A residue recovery tank 14 is connected to the terminal end of the heating reactor 2, and a cooling condenser 5 for cooling and condensing the generated polymer decomposition gas is connected to the upper part.

In the processing apparatus shown in FIGS. 5 and 6, a pressure adjusting valve 17 is inserted at the end of the gas withdrawing pipe 10, and by this pressure adjusting valve 17, the gas generated in the heating reaction apparatus 2 is generated. , Is retained in the cylinder 8 until a predetermined pressure is reached, and the inside of the cylinder 8 is maintained in a pressurized state of a predetermined pressure. In addition, it is sent to each pipe between the feeder 1 and the heating reaction device 2, between the heating reaction device 2 and the thermal decomposition tank 4, and between the thermal decomposition tank 4 and the residue recovery tank 14, respectively. A valve (stop valve) 18 is provided.

Furthermore, in the processing apparatus shown in FIG.
In place of the heating reaction device 2 having the continuous feed moving mechanism 6, a heating reaction tank 19 having an agitator 13 is provided,
Further, a temperature control device 20 is provided to control the heating temperature in the heating reaction tank 19 so as to make a predetermined change with time. Then, the plastic waste supplied by the feeder 1 by a fixed amount is pyrolyzed in a batch manner in the heating reaction tank 19, and the plasticizer is decomposed and the hydrogen chloride is desorbed, and then the residual. The substance is put into the thermal decomposition tank 4 so that the polymer is dried and thermally decomposed.

Next, concrete examples in which plastic waste is recycled by using these processing apparatuses will be described.

Example 1 50 parts of polyvinyl chloride having a number of monomers of 1000 was mixed with 50 parts of DOΙ and sufficiently kneaded to homogenize the composition, and then pelletized to a diameter of 2 mm to 3 mm was used as a sample. It was put into the apparatus shown in FIG. 1 and processed as follows.

First, the sample was charged into the feeder 1, and was fed to the heating reactor 2 at a rate of 20 g / min.
Then, based on the results of preliminary experiments conducted in advance, 300
The temperature was raised to around 0 ° C to reduce the viscosity of the sample. Feeder 1
Since the sample that was solid at the time of being charged into the reactor has a reduced viscosity due to heating and becomes fluidized, the packing density per unit volume in the heating reactor 2 increases until gasification occurs. Therefore, in the heating reaction device 2, heat is efficiently transferred from the outer wall of the cylinder 8 to the sample.

Then, heating was performed while controlling the temperature in the cylinder 8 of the heating reaction device 2 by the heating control device 3 as shown below. That is, as shown in FIG.
Adjust the temperature so that the sample reaches the temperature of 250 to 270 ° C at the position of about 1/10 to 1/5 of the total length of the cylinder 8 in the length direction (sample feeding direction) from the sample supply port of the cylinder 8. Controlled heating was performed. Then, from this position (about 1/10 to 1/5 of the total cylinder length from the supply port) to about 1/2 of the total length, heating was performed to reach 300 ° C. From the gas outlet 11 at a position of about 1/2), 3.7 g of phthalic anhydride, 0.5 g of water and 5.6 g of chain organic compound could be recovered on average per minute. At this point, the amount of hydrogen chloride and other gases produced and recovered was extremely small. Next, when the heating reactor 2 was operated so that the temperature from the supply port reached 350 ° C from the position of about 4/5 to 9/10 of the total length of the cylinder, from the gas discharge port 11 at the end of the cylinder 8. , 5.8 g of hydrogen chloride and 1.5 g of chain-like organic compounds could be recovered per minute on average, respectively. Further, from the terminal end of the cylinder 8, a residue obtained by kneading a black powder was sent out at a rate of 2.9 g / min.

Next, the residue was collected and 100 g was put into the thermal decomposition tank 4 and heated by a heater. Before the temperature reached 100 ° C., 10% by weight of sodium hydroxide (hereinafter , 10%) was added, and the mixture was stirred for 15 minutes while continuing heating. When the temperature reached 450 ° C, it was held for 1 hour, and then heated again to raise the temperature, and when it reached 500 ° C, the heating was terminated. At this time, a weight loss of 40 g was observed due to the generation of decomposition gas. The generated gas was cooled and condensed by the cooling condenser 5 to be collected and analyzed. As a result, it contained a large amount of chain hydrocarbons having 4 to 15 carbon atoms, and among them, the ratio of components having 7 to 12 carbon atoms was high. It was found that they are similar to the components contained in commercially available light oil and heavy oil. Furthermore, when the chlorine content of the recovered component was measured, it was 0.03% by weight (hereinafter,
Show as%. ) It turned out to be:

Example 2 Using the processing apparatus shown in FIG. 3, the same sample made of polyvinyl chloride and DOP as in Example 1 was processed as follows.

First, the sample is charged into the feeder 1, and the feeder 1 supplies the sample to the heating reactor 2 at a rate of 20 g / min.
Heating was performed while controlling the temperature in the cylinder 8 of the heating reaction device 2 by the heating control device 3 as described below. That is, as shown in FIG. 9, at a position of about 1/10 of the entire length of the cylinder 8 in the length direction from the sample supply port of the cylinder 8,
Heating was performed while controlling the temperature so that the sample reached a temperature of 250 to 270 ° C. Next, from this position (about 1/10 of the total cylinder length from the supply port), about 1/3 of the total length
When heated up to the position of 300 ℃,
It was possible to collect 3.7 g of phthalic anhydride, 0.5 g of water and 5.6 g of chain organic compounds on average every minute from the gas outlet 11 at this position (about 1/3 of the total cylinder length). . At this point, the amount of hydrogen chloride and other gases produced and recovered was extremely small. Next, when the heating reactor 2 was operated so as to reach 350 ° C. by the length from the supply port to the position of about 3/4 of the total cylinder length, the heating reactor 2 was operated at this position (about 3/4 of the total cylinder length). From the gas outlet 11, an average of 5.8 g of hydrogen chloride and 1.5 g of a chain organic compound could be recovered each minute. Therefore, an alkali injecting device 12 provided at this position in the cylinder 8 injects a 1% sodium hydroxide aqueous solution at a rate of 30 g / min, and further controls the temperature so that it reaches 500 ° C. at the end of the cylinder 8. While heating while, from the end of the cylinder 8,
The residue, which was like a black powder kneaded, was delivered at a rate of 1.5 g / min. In addition, about the total length of the cylinder 8
The gas generated in the section from the 3 / 4th position to the end part was cooled and condensed by the cooling condenser 5 and collected and analyzed, and it contained a large amount of chain hydrocarbons having 4 to 15 carbon atoms, among which the carbon number was It was found that the ratio of 7 to 12 was high, and it was similar to the components contained in commercially available light oil (light oil) and heavy oil. Furthermore, when the chlorine content of the recovered component was measured, it was found to be 0.03% or less.

Example 3 Using the same processing apparatus shown in FIG. 1 as in Example 1, a mixed material of polyvinyl chloride and polypropylene mixed with a plasticizer was treated in the following manner.

50 parts of polyvinyl chloride with a quantity of 1000
After mixing 50 parts and kneading thoroughly to make the composition uniform, 3 mm
A pellet-shaped sample having a diameter of 5 mm is supplied from the feeder 1 to the heating reaction device 2 at a rate of 20 g per minute, and heating is performed while controlling the temperature in the cylinder 8 by the heating control device 3 as shown below. Was done. That is, as shown in FIG. 10, heating is performed while controlling the temperature so that the sample reaches 350 ° C. at a position from the sample supply port of the cylinder 8 in the longitudinal direction at about 1/10 to 1/5 of the entire cylinder length. Was done. Next, when the heating reactor 2 was operated while maintaining 350 ° C from this position (about 1/10 to 1/5 of the cylinder length from the supply port) to about 1/2 of the cylinder length, From the gas discharge port 11 at the position (about 1/2 of the total length), 5.8 g of hydrogen chloride and 2.9 g of phthalic anhydride could be recovered on average per minute. At this time, a gas of a chain organic compound which is a lower hydrocarbon was generated. Next, the length from the supply port to the position of about 4/5 to 9/10 of the total cylinder length
When the heating reactor 2 was operated so as to reach ℃,
0.8g per minute on average from the gas outlet 11 at the end of the cylinder 8.
It was possible to recover each of phthalic anhydride and 1.5 g of the liquefied chain organic compound. Further, from the terminal end of the cylinder 8, a residue obtained by kneading a black powder was sent out at a rate of 2.9 g / min.

Next, the residue was collected to make 50 g, and a mixture of this residue with 50 g of polypropylene was put into the thermal decomposition tank 4 and heated by a heater. Before the temperature reaches 100 ° C., 5 g of a 10% aqueous solution of sodium hydroxide is added by the alkali injecting device 12 and stirred for 15 minutes while heating,
When the temperature reached 450 ° C and held for 1 hour, a weight loss of 70 g was observed due to the generation of decomposition gas. After that, it was heated again to raise the temperature, and when it reached 500 ° C, the heating was terminated. The generated gas was cooled and condensed by the cooling condenser 5 and recovered and analyzed. It contained a large amount of chain hydrocarbons having 4 to 15 carbon atoms, such as trimers and tetramers of propylene. Among them, the carbon number was 7 It was found that the ratio of 12 components was high, and it was similar to the components contained in commercially available light oil (light oil) and heavy oil. Furthermore, when the chlorine content of the recovered component was measured, it was found to be 0.02% or less.

Example 4 50 parts of polyvinyl chloride having a monomer number of 1000 was mixed with 50 parts of DOΙ and sufficiently kneaded to homogenize the composition, and then pelletized in a diameter of 3 mm to 5 mm was used as a sample. It was put into the apparatus shown in FIG. 5 and processed as follows.

First, the sample was put into the feeder 1, and was fed to the heating reactor 2 at a rate of 20 g / min. Then, the temperature in the cylinder 8 of the heating reaction device 2 is
While controlling as follows by the heating control device 3,
Heating was performed. That is, as shown in FIG. 11, from the sample supply port of the cylinder 8 in the length direction, approximately 1/1 of the total length of the cylinder is obtained.
Heating was performed while controlling the temperature so that the sample reached a temperature of 250 ° C to 270 ° C at a position of 10 to 1/5.
Then, from this position (about 1/10 to 1/5 of the cylinder length from the supply port) to about 1/2 of the total length, 300 ° C
When heated so as to reach, the gas is released from the gas release port 11 at this position (position of about 1/2 of the total cylinder length), and the pressure in the cylinder 8 is adjusted to a predetermined pressure (adjusted by the pressure adjusting valve 17). When the gauge pressure reached 4 kgf / cm ² ), the maximum gas emission was reached, and on average 3.7 g of phthalic anhydride and 6.1 g of chain organic compounds could be recovered per minute, respectively. At this point, the amount of hydrogen chloride and other gases produced and recovered was very small. Furthermore, the temperature from the supply port is 350 ° C from the position of about 4/5 to 9/10 of the total cylinder length.
When the heating reactor 2 is operated so as to reach the temperature, the gas is released from the gas discharge port 11 at the end of the cylinder 8 and the pressure in the cylinder 8 is kept at a predetermined pressure of 4 kgf / cm ²
When the (gauge pressure) was reached, the gas was released maximally, and an average of 5.7 g of hydrogen chloride and 1.5 g of chain organic compounds could be recovered each minute. Further, from the end portion of the cylinder 8, a residue such as black powder kneaded and solidified,
It was sent out at a rate of 2.9g per minute.

Next, the residue is collected and put into a thermal decomposition tank 4 having a stirrer 13 and heated by a heater. Before the temperature reaches 100 ° C., 10% of sodium hydroxide is charged by an alkali injecting device 12. 10 g of an aqueous solution was added, and the mixture was stirred for 15 minutes while continuing heating. Gas generation became vigorous when the temperature reached 450 ° C, so this state was maintained for 1 hour, after which the temperature was raised again to 500 ° C and heating was terminated. At this time, due to the generation of decomposition gas,
A weight loss of 40% was observed with respect to the weight of the added residue. In addition, when the generated gas was cooled and condensed by the cooling condenser 5 and collected and analyzed, it contained a large amount of chain hydrocarbons having 4 to 15 carbon atoms, and among them, the ratio of light components having 5 to 10 carbon atoms was found. It became higher, and it was found to be similar to the components contained in commercially available light oil (light oil). further,
When the chlorine content of the recovered components was measured, it was 0.03%
It turned out to be: Furthermore, in this example, compared with Example 1, the time required for processing until oil recovery was significantly shortened, and the amount of plastic waste that can be processed per unit time was increased by 1.5 to 2 times. It turned out to be increasing.

Example 5 Using the processing apparatus shown in FIG. 7, the same sample made of polyvinyl chloride and DOP as in Example 1 was processed as follows.

First, the sample was put into the feeder 1, and was fed by the feeder 1 at a rate of 20 g per minute for 20 minutes to the heating reaction tank 19 equipped with the stirrer 13. When heating was performed while the temperature was controlled by the temperature control device 20 so that the temperature of the sample reached 300 ° C in the heating reaction tank 19, about 1 hour passed, and the pressure in the tank was adjusted by the pressure adjusting valve 17. When a given pressure (4 kgf / cm ^{2 in} gauge pressure) is reached, the maximum gas release through the pressure regulating valve 17 is reached, averaging 3.7 g phthalic anhydride and 0.5 g water and 5.6 g / min. It was possible to recover g of each chain organic compound. At this point, the amount of hydrogen chloride and other gases produced and recovered was extremely small. Then, when the temperature of the heating reaction tank 19 was increased so that the temperature of the sample reached 350 ° C., when the pressure in the tank reached a predetermined pressure (4 kgf / cm ^{2 in} gauge pressure), the pressure adjustment was performed. The release of gas through the valve 17 was maximized, and an average of 5.8 g of hydrogen chloride and 1.5 g of chain organic compound could be recovered per minute, respectively. When the amount of gas released suddenly decreased, the stop valve 18 at the bottom of the heating reaction tank 19 was opened, and the molten residue was charged into the thermal decomposition tank 4. Next, when heating was performed while adjusting the temperature so that the temperature in the thermal decomposition tank 4 was 450 ° C., gas was vigorously generated after 1 hour, and the light was generated by cooling and condensing with the cooling condenser 5. A yellow, transparent oil could be recovered. After the residue was transferred from the lower part of the thermal decomposition tank 4 to the residue recovery tank 14, the weight of the recovered oily substance was measured, and it was confirmed that it was approximately 10% of the weight of the charged sample. In addition, analysis of the components of the recovered oily substance revealed that it contained a large amount of chain hydrocarbons with 4 to 15 carbon atoms, and among them, the proportion of light components with 5 to 10 carbon atoms was high. It was found to be similar to the components contained in oil (light oil). Furthermore, when the chlorine content of the oily substance was measured, it was found to be 0.03% or less.

Comparative Example Using the processing apparatus shown in FIG. 1, the same pellet-shaped sample as in Example 4 was processed as follows.

First, the sample is charged into the feeder 1, and the feeder 1 supplies the sample to the heating reactor 2 at a rate of 20 g / min.
The heating was carried out in the cylinder 8 so as to obtain a single mode heating temperature distribution. That is, as shown in FIG.
From 1/10 of the total cylinder length in the length direction from the sample supply port
At the 1/5 position, the sample was rapidly heated to reach 500 ° C. At this time, the gas discharge port 1 at each position of the cylinder 8
Emission of decomposition gas was observed from No. 1, and an average of 3.0 g of phthalic anhydride per minute, 0.5 g of water and 3.6 g of chain organic compound were respectively collected. At this point, the average amount of hydrogen chloride and other gases produced and recovered was 5.8 g per minute. In addition, cylinder 8
From the end of the, a residue like black powder kneaded was sent out at a rate of 7.1 g per minute.

Next, the residue was collected and 100 g was put into the thermal decomposition tank 4 and heated by a heater. Before the temperature reached 100 ° C., 10 g of a 10% aqueous solution of sodium hydroxide was charged by the alkali injecting device 12. Add and stir for 15 minutes with continued heating. And when the temperature reaches 450 ℃
The temperature was maintained for 1 hour, and then the temperature was raised again by heating, and when the temperature reached 500 ° C, the heating was stopped. At this time, a mass reduction of 30 g was observed due to the generation of decomposition gas. The generated gas was cooled and condensed by the cooling condenser 5 to be recovered and analyzed. As a result, it contained a large amount of chain hydrocarbons having 4 to 15 carbon atoms, but the molecular weight distribution thereof was the oils obtained in Examples 1 to 5. No clear peak was seen in comparison with the above, and it was found that the molecular weight distribution is different from the components contained in commercially available light oil (light oil) and heavy oil. Furthermore, the chlorine content of the recovered components was measured and found to reach a maximum of 3%.

[0052]

As is apparent from the above description, according to the present invention, a plastic waste containing a halogen-containing polymer such as polyvinyl chloride containing a plasticizer is heated by controlling the temperature. , The decomposition of plasticizer and desorption of hydrogen halide gas such as hydrogen chloride can be performed efficiently, the generation of organic halogen compounds is suppressed, the halogen content such as chlorine is small, and the molecular weight distribution is uniform. Quality oil can be recovered. In addition, since the generated gas is retained in the closed reaction tank and the pressure in the tank is increased so that the dehydrohalogenation and the plasticizer can be decomposed more efficiently, the time required for the decomposition is further increased. It is shortened and the proportion of light components in the recovered oil is greatly increased.

Furthermore, in the present invention, since the generation of hydrogen halide, which is a corrosive gas, is locally limited, it is possible to limit the countermeasures against the corrosion of the apparatus to a limited portion, and the corrosion resistance of the apparatus is improved. The equipment cost required for improvement can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of an apparatus used in the method for treating plastic waste of the present invention.

FIG. 2 is an enlarged view showing the inside of the heating reaction device in FIG.

FIG. 3 is a schematic view showing another embodiment of the apparatus for treating plastic waste used in the present invention.

FIG. 4 is an enlarged view showing the inside of the heating reaction device in FIG.

FIG. 5 is a schematic view showing still another embodiment of the apparatus for treating plastic waste used in the present invention.

FIG. 6 is an enlarged view showing the inside of the heating reactor in FIG.

FIG. 7 is a schematic view showing another embodiment of the apparatus for treating plastic waste used in the present invention.

FIG. 8 is a graph showing changes in temperature at various positions in the heating reactor cylinder in Example 1.

FIG. 9 is a graph showing changes in temperature at various positions in the heating reactor cylinder in Example 2.

FIG. 10 is a graph showing changes in temperature at various positions in the heating reactor cylinder in Example 3.

FIG. 11 is a graph showing changes in temperature at various positions in the heating reactor cylinder in Example 4.

FIG. 12 is a graph showing changes in temperature at various positions in the heating reactor cylinder in the comparative example.

[Explanation of symbols]

1 ... Supplier 2 ... Heated reactor 3 ... Heating control device 4 ……… Thermal decomposition tank 5: Cooling condenser 6 ... Feed moving mechanism 8 ... Cylinder 10 ... Gas extraction piping 11 ... Gas outlet 12 ... Alkaline injection device 13 ……… Stirrer 17 ... Pressure adjustment valve 19 ... Heating reaction tank 20 ... Temperature controller

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Kanazawa 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Toshiba Corporation Yokohama office (56) Reference JP-A-6-179877 (JP, A) JP-A-7 -82569 (JP, A) JP-A-7-238182 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 11/00-11/28 B29B 17/00-17/02 C10G 1/10

Claims (5)

(57) [Claims] 1. A plastic waste containing a halogen-based polymer blended with a plasticizer is heated by pressurizing a generated gas and controlling the temperature to decompose the plasticizer to separate a decomposition product and a halogen. A method for treating plastic waste, comprising: a pyrolysis step of desorbing a compound gas; and an oilification step of dry distillation / pyrolysis of the residue of the pyrolysis step to produce and recover oil. . 2. In the thermal decomposition step, the plastic waste is subjected to a gauge pressure of 0 to 100 kgf / cm ² under pressure.
The method for treating plastic waste according to claim 1, wherein heating is performed at a temperature of 200 to 450 ° C. 3. The method for treating plastic waste according to claim 1, wherein the oiling step is carried out after adding an alkali to the residue of the thermal decomposition step. 4. A supply device for continuously supplying plastic waste and a feed moving mechanism, which heats the plastic waste continuously supplied by the supply device to decompose the plasticizer and remove hydrogen chloride. The heating reaction device to be desorbed, the heating temperature of the heating reaction device, a heating control device for controlling the heating temperature to a predetermined temperature at each position along the axial direction of the feed moving mechanism, and the heating reaction device from the heating reaction device. A plastic comprising a thermal decomposition device for dry-distilling and thermally decomposing the residue to generate a polymer decomposition gas, and a cooling condenser for cooling and condensing the polymer decomposition gas generated in the thermal decomposition device. Waste treatment equipment. 5. A heating reaction tank equipped with a stirrer for heating plastic waste to decompose a plasticizer and desorb hydrogen chloride, and a heating control device for controlling a heating temperature in the heating reaction tank. A pressure control valve for holding the inside of the heating reaction tank in a pressurized state of a set pressure, a thermal decomposition device for dry-distilling and thermally decomposing the residue from the heating reaction device to generate a polymer decomposition gas, and the heating An apparatus for treating plastic waste, comprising a cooling condenser for cooling and condensing a polymer decomposition gas generated in a decomposition apparatus.