JP2008095024A - Waste plastic recycling system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a streamlined and efficient waste-plastic recycling system capable of markedly cutting the equipment cost and the running cost through significant simplification, efficiency improvement and streamlining from a conventional recycling system. <P>SOLUTION: The waste-plastic recycling system comprises both a material recycling system which has a separation part for separating collected waste plastics into a resin having a quality suitable for material recycling and a resin having a quality unsuitable for material recycling, wherein a resin A having a quality for which material recycle is possible is subjected to material recycling, and a pyrolysis liquefaction recycling system in which a resin B having a quality for which material recycle is impossible is subjected to pyrolysis liquefaction and is collected as a decomposed oil. The waste-plastic recycling system is characterized in that both material recycling and pyrolysis liquefaction recycling can be performed in parallel. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a waste plastic recycling system for recycling waste plastic, particularly mixed waste plastic including polyvinyl chloride resin (hereinafter referred to as PVC), polyethylene terephthalate (hereinafter referred to as PET), and the like.

In recent years, as the use of plastics has increased, the amount of plastics to be discarded has become enormous, contributing to environmental problems such as the shortage of landfill sites and the generation of harmful gases by incineration.
At present, a waste plastic recycling system called material recycling is often used as a countermeasure.

  In material recycling, pellets are first made from waste plastic, and products that can be recycled, such as pallets, are manufactured. However, when used for pellets, etc., only PP and PE are selected and recovered. Resins such as PS, PVC, PVDC, PET, and acrylic are not recycled, and are disposed of as industrial waste and landfill. Has been. For this reason, there is a problem that the actual recycling rate is about 50%, and the remaining 50% is disposed of. In addition, since it takes a lot of manpower to sort and collect only PP and PE, not only does the operation cost increase, but in material recycling, pellets must be made in a high quality and high purity with no dirt. Therefore, there is a problem that the waste plastic as a raw material has to be washed, a large amount of waste water is discharged, and there is a problem that a running cost such as this waste water treatment is required, and there is a problem that the treatment cost is high.

On the other hand, FIG. 9 is a series of flowcharts of the configuration diagram of the waste plastic oil processing system developed by the present applicant.
In the case of general waste plastics, waste plastics collected separately by local governments or the like first enter the receiving stock yard 1 of the sorting facility. Subsequently, the waste plastic is broken by the bag breaking machine 2 and, after the hand sorting line 3 separates and removes foreign objects such as stones, paper, and wood in addition to large metals, the bale compressor 4 Compressed into a bale. The line so far is performed at the sorting facility.

  Waste plastic that has been compressed into a bale at the sorting facility enters the pretreatment process of the oil treatment facility. Thereafter, the waste plastic is crushed and shredded by a crusher 5, dried by a dryer 6, further sorted by a mechanical sorter 7, and then turned into a waste plastic granulated product by a granulator 8. Alkaline such as powdered slaked lime is added to the waste plastic granulated material from the slaked lime feeder 9 and stored in the granulated product silo 10. It is also possible to transfer the granulated product from the granulated product silo 10 to the flexible container pack 11 or the like and transfer it to another processing place or temporary storage place. The line from the crusher 5 to the granule silo 10 up to here is performed in the sorting facility in the pretreatment process of the oil treatment facility.

The waste plastic granulated product cut out from the granulated product silo 10 in the pretreatment step by a fixed amount passes through a desalinator hopper (granulated product hopper) 12 and a screw type dechlorinator (hereinafter referred to as a desalinator) 13. Is heated to around 350 ° C. to remove chlorine from polyvinyl chloride (PVC).
The dechlorinated molten plastic flows down to the melting tank 14 and is heated and held and stirred at about 350 ° C. in the melting tank 14. The dehydrochlorinated gas is guided to the desalted gas combustion furnace 16 through the desalted gas pipe 15, absorbed in water by the hydrogen chloride absorption tower 17 to become hydrochloric acid, and collected in the hydrochloric acid tank 18.

On the other hand, the molten plastic transferred from the melting tank 14 to the thermal decomposition apparatus 19 is heated and heated up to about 420 ° C. in the thermal decomposition apparatus 19 and is thermally decomposed to generate a thermal decomposition gas. The pyrolysis gas is condensed by the ejector 20 that sprays the cracked oil cooled by the cracked oil cooler 22, and collected in the cracked oil drum 21.
This cracked oil is led to a product oil recovery tower (distillation tower) 23 and fractionated by the difference in boiling range. Then, heavy oil equivalent to heavy oil, medium oil equivalent to light oil, and light oil equivalent to kerosene are respectively collected in heavy oil tank 24, medium oil tank 25, and light oil tank 26. The recovered heavy oil, medium oil, and light oil are shipped to each use destination.

  On the other hand, the pyrolysis residue remaining without being decomposed by the pyrolyzer 19 is discharged from the pyrolyzer 19 and conveyed by the residue cooling conveyor 27, and a residue recovery hopper (not shown) as a powdery residue. And then collected in a residue container (not shown). This pyrolysis residue is also used as a solid fuel with a combustion calorie equivalent to that of coal, and the residue can be transported to the site of use in a residue container. Furthermore, when this powdery residue is granulated, it becomes a highly versatile solid fuel. It can also be processed into solid fuel and transported to the site of use.

Further, the low boiling point gas component not fractionated as oil in the distillation tower 23 and the gas component from the hydrogen chloride absorption tower 17 are burned at 850 ° C. in the exhaust gas combustion furnace 28. And after detoxifying as high temperature combustion exhaust gas, after exhaust heat recovery with the exhaust gas boiler 29, it discharge | releases to air | atmosphere.
Recently, not only chemical recycling and thermal recycling of waste plastic product oil recovered by waste plastic oil processing equipment, but also a true return of light oil fractionated in the product oil recovery process to the oil refinery process of the oil refinery. Feedstock recycling ga which is the ultimate recycling has been started. This has made it possible to effectively recycle limited oil resources over and over again.

  Waste plastic oil processing recycling with such a system configuration can continuously recycle waste plastic and recycle all products (produced heavy oil, medium oil, light oil, residue, hydrochloric acid, off-gas). This is an epoch-making processing form.

  However, in waste plastic oil processing recycling, in addition to foreign materials such as iron, aluminum and copper, foreign materials such as sand, stone, paper, and wood, PET, PVC, etc. in waste plastic collected in general waste The oil-incompatible material is mixed with incomplete separation. Therefore, there are mainly two major inefficiencies:

  1) First, in the sorting facility, a hand sorting line that sorts and removes foreign objects such as stones, paper, and wood in addition to large metals in the hand sorting line, and machine sorting in the pre-processing step of the oil treatment facility in the subsequent process There is a problem that sorting is performed twice. In other words, the foreign material in the waste plastic can be thoroughly removed by sorting twice, and troubles in the downstream desalination oil treatment process, such as wear of screws and cylinders in the desalination equipment, There is a merit that troubles such as screw wear, ceramic ball wear and breakage in the pyrolyzer, blockage of valves and pipes, etc. are eliminated. However, since the collected waste plastic has a very low bulk density and is bulky, there is a problem that the sorting facility in the initial process becomes very large and the site area of the facility becomes large.

  2) In addition, since the collected waste plastics also contain resins that are incompatible with oiling such as PVC and PET, additional equipment is required so that they can be stably oiled even if they are mixed. There is a problem of becoming. That is, as a countermeasure against the mixing of PET, a facility for adding an alkali has to be installed, and there is a problem that the facility for this purpose and an increase in running cost associated with the addition of alkali arise. In addition, as a countermeasure against the entry of PVC or the like, a hydrochloric acid recovery process such as a desalting apparatus, a desalting gas combustion furnace, a hydrochloric acid recovery tower, and a hydrochloric acid shipping facility must be installed. Therefore, this also causes a problem that the facility for this purpose and the running cost increase.

  Because of these two major inefficiencies, the entire facility becomes large, and the plant equipment cost is increased, and the running cost is also increased. For this reason, there is a big problem that it is difficult for each local government to return the waste plastic to the original oil and to establish an oil processing facility that should be an optimal recycling facility as a community-based type.

  The pyrolysis oil recovered in the cracking oil drum is guided to the distillation tower and fractionated according to the difference in boiling range, and recovered as heavy oil equivalent to heavy oil, medium oil equivalent to light oil, and light oil equivalent to kerosene. Is done. The recovered heavy oil, medium oil, and light oil are shipped to each user. Therefore, there is a problem that the production oil recovery process (distillation process) in the downstream process becomes very large, the site area of the facility becomes large, and the operation of the plant becomes complicated. In this regard, a demonstration operation of feedstock recycling that returns pyrolysis oil to the original oil of the refinery is progressing. In the future, it is expected that by directly sending the pyrolysis oil to the refinery, it is possible to achieve true recycling of the plastic and to construct a simple oil processing apparatus.

Patent document 1 is a technology related to a waste plastic oil processing apparatus that accepts waste plastics including vinyl chloride resin, PET, etc., and that performs oil conversion processing, and a waste plastic oil processing method previously proposed by the present applicant. is there.
JP 2006-16594 A

  In view of both the problems of such material recycling methods and the problems of pyrolysis oil-based recycling, the present invention combines the good points of both methods to produce waste plastics, particularly PVC, PET, etc. In the waste plastic processing to process the mixed waste plastics containing oil, the problem that both conventional recycling methods are complicated is solved, and the equipment cost, The purpose is to provide a rational and efficient waste plastic recycling system that can greatly reduce running costs.

  1) The waste plastic recycling system according to the first aspect of the present invention has a sorting section for sorting the collected waste plastic into a resin that is suitable for material recycling and a resin that is not suitable for material recycling. The material recycling system that recycles the resin that can be recycled, and the heat that can be recovered from the waste plastic that cannot be recycled. It has both a cracked oil-recycling system and is characterized in that both material recycling and pyrolysis-oil recycling can be performed in parallel.

2) The waste plastic recycling system according to the second aspect of the present invention is such that the thermal cracking oil recycling system performs dehydrochlorination treatment of a polyvinyl chloride resin mixed in a resin whose material cannot be recycled. The hydrogen chloride treatment process, the pyrolysis process that further pyrolyzes the material after dehydrochlorination treatment to generate pyrolysis gas, and the pyrolysis gas generated by pyrolysis is directly contacted with the cracked oil to condense and decompose It includes a pyrolysis oil recovery process that recovers as oil, a residue recovery process that cools and recovers the residue generated in the pyrolysis process, and a non-condensable gas combustion process that burns the non-condensable gas generated by pyrolysis It is characterized by that.
3) In the waste plastic recycling system according to the third aspect of the present invention, the dehydrochlorination treatment is a screw feeder in the dehydrochlorination treatment step of dehydrochlorinating a resin whose material cannot be recycled in the above 2). This system is equipped with a volume reduction machine that allows the air mixed into the waste plastic input material to be expelled and reduced before being introduced into the screw feeder as a step before being introduced into the screw feeder. And

  4) In the waste plastic recycling system according to the fourth aspect of the present invention, in the above 2) or 3), the pyrolysis oil conversion recycling system contains polyethylene terephthalate (PET) in a resin whose material cannot be recycled. In this case, the function of adjusting and adding the amount of alkali added according to the mixing rate of PET in the waste plastic input material to be introduced into the thermal decomposition apparatus is a thermal decomposition apparatus after the dehydrochlorination process. It is characterized by being prepared for the stage before the introduction stage.

5) The waste plastic recycling system according to the fifth aspect of the present invention is characterized in that, in 4), the alkali to be added is slaked lime.
6) The waste plastic recycling system according to the sixth aspect of the present invention is characterized in that, in the above-mentioned 5), the amount of alkali added is adjusted by the measured pH value of the produced cracked oil.

  7) The waste plastic recycling system according to the seventh aspect of the present invention is the combustion gas discharged from the combustion furnace in the non-condensable gas combustion step in which the non-condensable gas generated by pyrolysis is burned in the above 2) to 6) Is a heat source for the thermal decomposition apparatus.

  8) In the waste plastic recycling system according to the eighth aspect of the present invention, in the above 7), the combustion furnace not only burns non-condensable gas generated by decomposition but also decomposes oil generated by thermal decomposition. It is also provided with a function capable of burning as fuel.

  9) In the waste plastic recycling system according to the ninth aspect of the present invention, in the above 2) to 8), not only the combustion gas discharged from the combustion furnace is used as the heating source of the thermal decomposition apparatus, but also the heating source of the boiler It is characterized by doing.

  The system of facilities that process waste plastics, especially mixed waste plastics including PVC, PET, etc., has so far been large in both the material recycling and pyrolysis oil recycling, and the initial construction cost of the plant has been increased. As a result, the running cost is increased, resulting in inefficiency. However, according to the present invention described above, these problems can be solved at the same time, and a simple system configuration can be achieved by combining material recycling and pyrolysis oil recycling, thereby reducing the cost and providing a plant capable of efficient and stable operation. Can be provided. In addition, this makes it easy to return waste plastic to the original oil and rationally install an oil treatment facility, which is originally an optimal recycling facility as a community-based type, together with material recycling.

Hereinafter, the waste plastic recycling system according to the present invention will be described in more detail. (1) The waste plastic recycling system of the present invention has a sorting unit that sorts the collected waste plastic into a resin that is suitable for material recycling and a resin that is not suitable for material recycling. A material recycling system that material-recycles plastic materials that can be recycled within waste plastics, and pyrolysis oil-recycling that recovers resin materials that cannot be recycled from the waste plastics as pyrolysis oils. The system is characterized in that both material recycling and pyrolysis oil recycling can be performed in parallel.
By adopting such a configuration, it is possible to provide a plant that has a simple system configuration, reduces costs, and can perform efficient and stable operation.

  (2) In the invention of the above (1), the pyrolysis oil recycling system includes a dehydrochlorination treatment process for dehydrochlorinating a polyvinyl chloride resin mixed in a resin of a material that cannot be recycled. Pyrolysis process that further pyrolyzes the material after dehydrochlorination treatment to generate pyrolysis gas, and pyrolysis that recovers pyrolysis gas generated by pyrolysis by directly contacting it with cracked oil and condensing it as cracked oil It is preferable to include an oil recovery step, a residue recovery step for cooling and recovering the residue generated in the thermal decomposition treatment step, and a non-condensable gas combustion step for burning non-condensable gas generated by thermal decomposition.

  By adopting such a configuration, it is possible to provide a plant that has a simple system configuration, reduces costs, and can perform efficient and stable operation. In addition, this makes it easy to return waste plastic to the original oil and rationally install an oil treatment facility, which is originally an optimal recycling facility as a community-based type, together with material recycling.

(3) In the above invention (2), the dehydrochlorination treatment is carried out with a screw feeder type device, and as a step before being put into the screw feeder, air mixed into the waste plastic input material is expelled and reduced in volume. It is preferable to provide a volume reduction machine that can be put into the screw feeder.
By adopting a method with a volume reducer in this way, the conventional crushing and granulation process steps can be omitted while maintaining the conventional processing capacity, and the equipment can be greatly simplified and the cost can be reduced. it can.

(4) In the invention of (2) or (3) above, the function of adjusting and adding the amount of alkali added according to the mixing ratio of PET in the waste plastic input material input to the thermal decomposition apparatus is removed. It is preferable to prepare for the stage before the charging stage to the thermal decomposition apparatus after the hydrogen chloride treatment process.
By adopting such a configuration, problems such as the progress of corrosion of downstream equipment and piping, or clogging with oil in equipment and piping, which has occurred in the conventional pyrolysis and oil recycling system, are resolved by material recycling and pyrolysis. It can also be solved in a waste plastic recycling system that can perform both oil-based recycling in parallel.

  (5) In the invention of (4), examples of the alkali to be added include slaked lime. Further, the amount of alkali to be added can be adjusted by the measured pH value of the produced cracked oil. Thereby, the waste plastic recycling system can be operated more stably.

(6) In the inventions of the above (2) to (5), the combustion gas discharged from the combustion furnace in the non-condensable gas combustion step for burning the non-condensable gas generated by pyrolysis is used as a heating source of the thermal decomposition apparatus. It is preferable to do.
In this way, non-condensable gas (off-gas) that cannot be stored can be used as a heat source for the thermal decomposition equipment, so that off-gas can be safely and stably processed in the system as well as waste plastic recycling. The energy efficiency of the system can be increased and more generated pyrolysis oil can be supplied to the user.

(7) In the invention of (6), the combustion furnace not only burns non-condensable gas generated by decomposition, but also has a function of burning cracked oil generated by thermal decomposition as fuel. Is preferred.
This configuration not only enables safe and stable treatment of off-gas in the system, but also increases energy efficiency in an optimal operating state that matches the usage status of the waste plastic recycling system and pyrolysis oil. More product pyrolysis oil can be supplied to the user.

(8) In the inventions of (2) to (7), it is preferable that the combustion gas discharged from the combustion furnace is not only used as a heating source for a thermal decomposition apparatus but also used as a heating source for a boiler.
By adopting such a configuration, the energy efficiency within the installation site can be increased, and more generated pyrolytic oil can be supplied to the user. Thereby, the waste plastic recycling system can be operated more stably.

Next, specific embodiments of the waste plastic recycling system according to the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a system flow of a waste plastic recycling system in the first embodiment of the present invention. In FIG. 1, the same parts as those in FIG.

  In the recycling system flow of FIG. 1, waste plastic that has been sorted and bale in a sorting facility is supplied to a waste plastic recycling system in the same manner as in the past. Here, first, similarly to the conventional pyrolysis oil recycling, it is crushed and shredded by the crusher 5 and dried by the drier 6. Further, not only the foreign material is removed by the mechanical sorter 7, but also only the resin of material that can be recycled, such as PP and PE, is separated and supplied to the material recycling system.

  In the material recycling system, the purity of the material is required. For this reason, the resin of recyclable material is washed to remove the adhered dirt, and then pelletized, and a recycled product such as a pallet is manufactured from the pellet. On the other hand, the resin of the material that cannot be recycled except the resin that is separated and sorted by the mechanical sorter 7 and can be recycled is supplied as it is to the pyrolysis oil recycling system. In addition, the code | symbol A in FIG. 1 shows the flow of resin in which material recycling is possible, and the code | symbol B shows the flow of resin in which material recycling is impossible.

  The material supplied to the pyrolysis oil recycling system is fluffy waste plastic. This material becomes a waste plastic granulated product in the granulator 8 as in the conventional oil processing system. Alkaline such as powdered slaked lime is added to the waste plastic granulated material from the slaked lime feeder 9 and stored in the granulated product silo 10. The waste plastic granulated product can be transferred from the granulated product silo 10 to the granulated product flexible container pack 11 and transferred to another processing place or temporary storage place.

  Waste plastic granulated material cut out from the granulated silo 10 in the pretreatment step in a fixed amount is subjected to heat treatment at around 350 ° C. in the desalinator 13 through the desalter hopper 12 to remove chlorine from the PVC. . Even if the fluffy waste plastic is not granulated and stored in the granulated silo 10, a simple configuration is possible in which the volume is reduced and supplied to the desalting apparatus 13 without being mixed with air. Is possible.

  The dechlorinated molten plastic flows down to the melting tank 14 and is heated and held at about 350 ° C. and stirred in the melting tank 14. After the agitation, the molten plastic is supplied with dehydrochlorinated gas through a desalted gas pipe 15 to a desalted gas combustion furnace 16, absorbed by water in a hydrochloric acid absorption tower 17 to become hydrochloric acid, and recovered in a hydrochloric acid tank 18. . On the other hand, the molten plastic transferred from the melting tank 14 to the thermal decomposition apparatus 15 is heated and heated up to about 420 ° C. in the thermal decomposition apparatus 19 and is thermally decomposed to generate a thermal decomposition gas.

  The pyrolysis gas is condensed by the ejector 20 that sprays the cracked oil cooled by the cracked oil cooler 22, and collected in the cracked oil drum 21. The cracked oil may be guided to the distillation tower 23 and fractionated into heavy oil, medium oil, and light oil. However, it is the most desirable method to feed the cracked oil as it is to the refinery and to recycle the feedstock to the raw material of petroleum products because it can reduce the environmental burden and build a true recycling society.

  Further, the pyrolysis gas generated in the pyrolysis device 19 includes a low-boiling gas component that could not be condensed even if it was condensed in the ejector 20. This low boiling point gas component is introduced into the exhaust gas combustion furnace 28 from above the cracked oil drum 21. The low boiling point gas component is completely burned in the exhaust gas combustion furnace 28 and detoxified as high temperature combustion exhaust gas. The exhaust heat of the high-temperature combustion exhaust gas generated in the exhaust gas combustion furnace 28 is used as a heating source for the thermal decomposition apparatus 19 and then released to the atmosphere. Note that, as in the conventional system, the high-side combustion exhaust gas generated in the exhaust gas combustion furnace 28 can be introduced into the exhaust gas boiler 29 and the like to recover the exhaust heat and then released to the atmosphere. In FIG. 1, reference numeral 31 is a dechlorination treatment process, reference numeral 32 is a thermal decomposition process, reference numeral 33 is a residue recovery process, reference numeral 34 is a pyrolysis oil recovery process, and reference numeral 35 is a non-condensable gas combustion process. Indicates.

  By the way, although FIG. 1 described the case where the plastic which can be material-recycled from a sorter is conveyed to a material recycling system, and the plastic which cannot be material-recycled is conveyed to a granulator, it is not limited to this. For example, a waste plastic recycling system as shown in FIG. 2 or 3 may be adopted.

  The system shown in FIG. 2 supplies the material recycling system with the entire amount of plastic resin from which foreign materials have been sorted without supplying the material recycling material selected by the mechanical sorter 7 to the material recycling system. Material residue that cannot be processed by the system (material recycle incompatible resin) is supplied to pyrolysis oil-recycling recycle, and processing operation is performed by pyrolysis oil-recycling recycle. In FIG. 2, the symbol A indicates a foreign material sorting plastic, and the symbol B indicates a material residue.

  The system shown in FIG. 3 not only removes foreign substances by the mechanical sorter 7, but also separates and sorts materials that can be recycled, such as PP and PE, and other resins that cannot be recycled. Is supplied to a pyrolysis oil-recycling recycling system as it is, and is subjected to a processing operation in a pyrolysis oil-recycling recycling system. In FIG. 2, symbol A 'indicates a selected plastic, and symbol B indicates a material residue.

  Even in the systems as shown in FIG. 2 and FIG. 3, both material recycling and pyrolysis oil recycling can be carried out in a rational manner. In addition, the processing flow of pyrolysis oil conversion recycling is not necessarily the above-described flow described here, and it is sufficiently conceivable to make a more simplified system.

  As described above, in the conventional waste plastic recycling system, both the material recycling and the pyrolysis oil-based recycling require a large facility as a whole, and the initial construction cost of the plant. In addition, the running cost is increased, resulting in an inefficient problem. However, according to the waste plastic recycling system according to the first embodiment, the above problems can be solved at the same time, and a simple system configuration can be achieved by fusing them together. be able to. In addition, this makes it easy to return waste plastic to the original oil and rationally install an oil treatment facility, which is originally an optimal recycling facility as a community-based type, together with material recycling.

Second Embodiment (Corresponding to Claim 2)
Please refer to FIG. FIG. 4 is a system flow of the waste plastic recycling system according to the second embodiment of the present invention. 4 identical to those in FIG. 1 are assigned the same reference numerals and descriptions thereof are omitted.
The recycling system shown in FIG. 4 includes a pyrolysis oil recycle facility (system) that converts a resin B, which cannot be recycled, into a pyrolysis oil and recovers it as a cracked oil. This system includes a dehydrochlorination process 31 for dehydrochlorinating a polyvinyl chloride resin (PVC, PVDC) C mixed in a resin B that cannot be recycled, and a material after dehydrochlorination. A pyrolysis treatment step 32 for further pyrolyzing the gas to generate a pyrolysis gas, a pyrolysis oil recovery step 34 for directly condensing and condensing the pyrolysis gas generated by pyrolysis with the cracked oil, and collecting it as a cracked oil; This is a waste plastic recycling system including a residue recovery step 33 for cooling and collecting the residue generated in the thermal decomposition treatment step, and a non-condensable gas combustion step 35 for burning the non-condensable gas generated by thermal decomposition.

  Waste plastic that has been sorted and bale in the sorting facility as in the past is supplied to the waste plastic recycling system. Here, first, similarly to the conventional pyrolysis oil recycle, it is crushed and shredded by the crusher 5 and dried by the drier 6. Further, the mechanical sorter 7 not only removes foreign substances but also separates and sorts only the resin A of material recyclable material, such as PP and PE, and supplies it to the material recycling system. In the material recycling system, the purity of the material is required. Accordingly, the resin that can be recycled is washed to remove the adhered dirt, and then pelletized, and a recycled product such as a pallet is manufactured from the pellet. The resin B refers to a resin other than the resin A and the polyvinyl chloride resin C.

  On the other hand, the non-material recyclable resins other than the material recyclable resin separated and sorted by the mechanical sorter 7 are collectively supplied to the pyrolysis oil recycling system. Resins made of materials that cannot be recycled are collectively supplied to the pyrolysis oil recycling system.

  The material supplied to the pyrolysis oil-recycling system is a dehydrochlorination treatment step 31 for dehydrochlorination treatment of polyvinyl chloride resin (PVC, PVDC) mixed in a resin that cannot be recycled. The pyrolysis process 32 that further pyrolyzes the material after the dehydrochlorination treatment to generate pyrolysis gas, and heat that directly contacts the pyrolysis gas generated by pyrolysis with the cracked oil to condense and recover it as cracked oil Through the cracked oil recovery step 34, the residue recovery step 33 for cooling and recovering the residue generated in the thermal decomposition treatment step, and the non-condensable gas combustion step 35 for burning the non-condensable gas generated by thermal decomposition, the total amount of waste plastic Is recycled.

  In this case as well, the cracked oil may be fractionated into heavy oil, medium oil, and light oil in a distillation tower (not shown). However, feedstock recycling that sends cracked oil directly to the refinery and returns it to the raw material of petroleum products is the most desirable method because it can reduce the environmental burden and build a true recycling society. Needless to say, in the case of a small-scale waste plastic recycling system, it can also be used as boiler fuel for factories. Further, the pyrolysis gas generated in the pyrolysis device 19 includes a low-boiling gas component (off-gas) that could not be condensed even if it is condensed in the ejector 20. This low boiling point component gas (off gas) is introduced into the off gas combustion furnace (not shown) from the upper part of the cracked oil drum 21.

The introduced low-boiling gas component (off-gas) is completely burned in an off-gas combustion furnace and detoxified as high-temperature combustion exhaust gas. The exhaust heat of the high-temperature combustion exhaust gas generated in this off-gas combustion furnace is used as a heating source for the thermal decomposition apparatus 19 and then released to the atmosphere. Here, as in the conventional system, the off-gas can be introduced into the exhaust gas combustion furnace 28, and the high-temperature combustion exhaust gas generated here can be introduced into the exhaust gas boiler 29 to recover the exhaust heat, and then released to the atmosphere.
In addition, the processing flow of pyrolysis oil conversion recycling is not necessarily the flow described here, and it is sufficiently conceivable to use a more simplified system.
The waste plastic recycling system of the second embodiment has the same effect as that of the first embodiment.

(Third embodiment) (corresponding to claim 3)
Please refer to FIG. FIG. 5 is a flow of the main part of the waste plastic recycling system in the third embodiment of the present invention. 5 identical to those in FIG. 1 are assigned the same reference numerals and descriptions thereof are omitted.

  5 includes a screw feeder type desalination apparatus 13, a volume reduction machine 36, a desalination apparatus 13, a melting tank 14, and a pyrolysis apparatus 19 into which waste plastic processing materials are introduced. Are arranged in this order from the upstream side to the downstream side. The volume reducer 36 has a function that allows the air mixed in the waste plastic input material to be expelled and reduced before being introduced into the screw feeder as a stage before being introduced into the screw feeder. As the mechanism of the volume reducing machine 36, the angle of the feed blade of the screw of the normal screw feeder system is angled on the discharge side to increase the compression rate, the air in the input material is returned to the input side, A mechanism is conceivable in which only the material is compressed and discharged from the outlet. In the demineralization apparatus 13 in the dehydrochlorination treatment step 31, dehydrochlorination treatment is performed on a resin that cannot be recycled.

Conventionally, in waste plastic recycling systems, if raw materials are not crushed and granulated, 1) they do not stably bite into a screw feeder type desalination apparatus that performs dehydrochlorination treatment, or 2) even if they bite, the bulk specific gravity is low. There was a problem that the amount of processing was reduced and the system could not be operated efficiently. On the other hand, in the case of the third embodiment, a volume reduction machine is installed so that the air mixed in the waste plastic input material is expelled and volume-reduced and then input into the screw feeder. Therefore, the conventional crushing and granulating process steps can be omitted while maintaining the conventional processing capacity, and the equipment can be greatly simplified and the cost can be reduced.
The waste plastic recycling system according to the third embodiment has the same effect as that of the first embodiment. In addition, by adopting a method of installing a volume reducer, the conventional crushing and granulating process steps can be omitted while maintaining the conventional processing capacity, and the equipment can be greatly simplified and the cost can be reduced.

(Fourth embodiment) (corresponding to claim 4)
Refer to FIG. FIG. 6 is a flow of the main part of the waste plastic recycling system according to the fourth embodiment of the present invention, which includes an alkali addition and pyrolysis oil recycle system with a volume reduction machine. However, in FIG. 6, the same parts as those in FIGS. 1 and 5 are denoted by the same reference numerals, and the description thereof is omitted.

  The recycling system of FIG. 6 is characterized in that a function 37 for adjusting the addition amount of alkali (for example, slaked lime) is added to the upper part of the desalinator hopper 12. This method is a pyrolysis oil-recycling system in which a resin with a material that cannot be recycled is pyrolyzed and recovered as cracked oil. Polyethylene terephthalate (PET) is contained in the resin with a material that cannot be recycled. It is effective when That is, the system has a function 37 for adjusting and adding the amount of alkali added according to the mixing ratio of PET in the waste plastic input material that is input to the thermal decomposition apparatus 19, and the heat after the dehydrochlorination process. This is provided for the stage before the charging stage to the decomposition apparatus 19.

  The function 37 is not limited to the place shown in FIG. 6 and may be installed in a place where the driving operation can be easily performed. Further, when the amount of PET in the resin can be measured, the measured value may be controlled using a parameter. Further, the pH value in the oil may be measured, and the amount of alkali added by the function 37 may be controlled by the measured value.

Conventionally, in the pyrolysis oil recycling system, when PET is mixed into the resin, the pyrolysis oil is acidified, and not only the downstream equipment and piping are corroded, but the pyrolysis oil is polymerized, There was a big problem that the oil hardened and blocked in the piping. However, according to the fourth embodiment, this problem can be solved even in a waste plastic recycling system that can perform both material recycling and pyrolysis oil-based recycling in parallel.
The waste plastic recycling system having the system flow configured as described above can stably operate the waste plastic recycling system.

(Fifth embodiment) (corresponding to claim 5)
Please refer to FIG. However, in FIG. 6, the same parts as those in FIGS. 1 and 5 are denoted by the same reference numerals, and the description thereof is omitted.

  In the fifth embodiment of the present invention, the alkali to be added is slaked lime. When the amount of PET in the resin can be measured, the measured value may be controlled by a parameter. Moreover, you may make it control the amount of slaked lime added by the said function 37 by measuring the pH value in oil, and the measured value. Slaked lime is easy to handle, and by mixing and adding it to the resin material before the volume reducer 36, stable and reliable operation control can be performed. This also makes it possible to stably operate the waste plastic recycling system.

(Sixth embodiment) (corresponding to claim 6)
Please refer to FIG.
In the sixth embodiment of the present invention, the amount of alkali to be added is adjusted by the measured pH value of the produced cracked oil. Here, the method of measuring the pH value in oil and controlling the amount of slaked lime added by the function 37 based on the measured value is the simplest, rational and stable method.
Thereby, the waste plastic recycling system can be operated more stably.

(Seventh embodiment) (corresponding to claim 7)
Please refer to FIG. However, in FIG. 7, the same parts as those in FIG.
FIG. 7 is a flow of the waste plastic recycling system in the seventh embodiment of the present invention. Specifically, in the flow of the waste plastic recycling system in which the combustion gas discharged from the exhaust gas combustion furnace 28 in the non-condensable gas combustion process for burning the non-condensable gas generated by thermal decomposition is used as a heating source of the thermal decomposition device 19. is there.

  In the flow of the waste plastic recycling system in FIG. 7, the combustion gas discharged from the exhaust gas combustion furnace 28 in the non-condensable gas combustion process for burning the non-condensable gas generated by pyrolysis is used as the heating source of the thermal decomposition device 19. It is what I did. This method makes it possible to utilize a non-condensable gas (off-gas) that cannot be stored as a heating source of the thermal decomposition apparatus 19. Therefore, not only can the off-gas be safely and stably processed in the system, but also the energy efficiency of the waste plastic recycling system can be improved and more generated pyrolytic oil can be supplied to the user.

(Eighth embodiment) (corresponding to claim 8)
Please refer to FIG. However, in FIG. 8, the same parts as those in FIG.
FIG. 8 is a flow of the waste plastic recycling system in the eighth embodiment of the present invention. Specifically, the flow of the waste plastic recycling system using the combustion gas discharged from the exhaust gas combustion furnace 28 of the non-condensable gas combustion process 35 for burning the non-condensable gas generated by thermal decomposition as a heating source of the thermal decomposition device 19. It is.

  This system has a function of burning not only off-gas but also cracked oil generated by pyrolysis as fuel, so that it can be used as a heating source of the thermal cracking device 19. Therefore, not only can the off-gas be safely and stably processed in the system, but it can also increase energy efficiency and generate more heat in an optimal operating state that matches the usage conditions of the waste plastic recycling system and pyrolysis oil. Cracked oil can be supplied to users.

(Ninth embodiment) (corresponding to claim 9)
Please refer to FIG. 7 and FIG. 7 and 8, the same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.
The waste plastic recycling system according to the ninth embodiment of the present invention not only uses the combustion gas discharged from the exhaust gas combustion furnace 28 as the heating source of the thermal decomposition apparatus 19 but also the heating source of the boiler.
This system not only allows safe and stable treatment of off-gas in the system, but also enables it to be used as a boiler heating source. Therefore, the energy efficiency in the place of installation can be improved and more generated pyrolytic oil can be supplied to the user. Thereby, the waste plastic recycling system can be operated more stably.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the spirit of the invention in the stage of implementation. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

FIG. 1 is a system flow of a waste plastic recycling system in the first embodiment of the present invention. FIG. 2 is a system flow showing a modification of the waste plastic recycling system in the first embodiment of the present invention. FIG. 3 is a system flow showing another modification of the waste plastic recycling system according to the first embodiment of the present invention. FIG. 4 is a system flow of the waste plastic recycling system according to the second embodiment of the present invention. FIG. 5 is a system flow of the waste plastic recycling system according to the third embodiment of the present invention. FIG. 6 is a system flow of the waste plastic recycling system in the fourth, fifth and sixth embodiments of the present invention. FIG. 7 is a system flow of the waste plastic recycling system in the fifth and ninth embodiments of the present invention. FIG. 8 is a system flow of the waste plastic recycling system in the sixth and ninth embodiments of the present invention. FIG. 9 is a system flow of a conventional waste plastic recycling system.

Explanation of symbols

  31 ... Dehydrochlorination treatment step, 32 ... Thermal decomposition treatment step, 33 ... Residue recovery step, 34 ... Thermal decomposition recovery step, 35 ... Non-condensable gas combustion step, 36 ... Volume reducer, 37 ... Alkali (slaked lime) addition adjustment function.

Claims (9)

It has a sorting section that sorts the collected plastic waste into a resin that conforms to material recycling and a resin that does not conform to material recycling.
The material recycling system that recycles the resin that can be recycled from the waste plastic sorted by the sorting section, and the resin that cannot be recycled from the waste plastic is thermally decomposed and recovered as cracked oil. With both thermal cracking and oil recycling system
Waste plastic recycling system that can perform both material recycling and pyrolysis oil recycling in parallel. The pyrolysis oil conversion recycling system is
A dehydrochlorination process for dehydrochlorinating a polyvinyl chloride resin mixed in a resin that cannot be recycled;
A pyrolysis process for further pyrolyzing the dehydrochlorinated material to generate pyrolysis gas;
A pyrolysis oil recovery process in which pyrolysis gas generated by pyrolysis is directly contacted with the cracked oil to be condensed and recovered as cracked oil;
A residue recovery step for cooling and recovering the residue generated in the thermal decomposition treatment step;
The waste plastic recycling system according to claim 1, further comprising a non-condensable gas combustion step of burning non-condensable gas generated by pyrolysis. In the dehydrochlorination process, which first dehydrochlorinates a resin that cannot be recycled,
Dehydrochlorination treatment is performed with a screw feeder type device,
3. A volume reducer that allows the air mixed in the waste plastic input material to be expelled and volume-reduced and then introduced into the screw feeder as a previous stage to be introduced into the screw feeder. Waste plastic recycling system. The pyrolysis oil conversion recycling system is
In the case where polyethylene terephthalate (PET) is contained in a resin that cannot be recycled,
The function to adjust the addition amount of alkali according to the mixing rate of PET in the waste plastic input material to be input to the thermal decomposition equipment, before the introduction stage to the thermal decomposition equipment after the dehydrochlorination process The waste plastic recycling system according to any one of claims 2 and 3, wherein the waste plastic recycling system is provided for the stage. The waste plastic recycling system according to claim 4, wherein the alkali to be added is slaked lime. 6. The waste plastic recycling system according to claim 5, wherein the amount of alkali to be added is adjusted according to the measured pH value of the produced cracked oil. 7. The combustion gas discharged from a combustion furnace in a non-condensable gas combustion process for burning non-condensable gas generated by pyrolysis is used as a heating source of the thermal decomposition apparatus. Waste plastic recycling system. 8. The waste plastic according to claim 7, wherein the combustion furnace has a function of not only burning non-condensable gas generated by decomposition but also combusting cracked oil generated by thermal decomposition as fuel. Recycling system. The waste plastic recycling system according to any one of claims 2 to 8, wherein the combustion gas discharged from the combustion furnace is used not only as a heating source of a thermal decomposition apparatus but also as a heating source of a boiler.

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