Treatment device and treatment method for recovering cracked oil from pyrolysis gas

Abstract

To provide a treatment apparatus capable of improving quality of a decomposition oil recovered from a pyrolysis gas generated by pyrolysis of organic matter such as waste plastics.SOLUTION: A treatment apparatus 2 comprises: a physical separation part 15 that physically removes particles from a pyrolysis gas; and an oil recovery part 16 that recovers a decomposition oil from the pyrolysis gas from which the particles have been removed. The physical separation part 15 comprises a washing dust collector 25 that removes the particles from the pyrolysis gas by spraying a washing medium onto the pyrolysis gas.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a treatment device and a treatment method for recovering cracked oil from pyrolysis gas generated by the thermal decomposition of organic matter such as waste plastics, biomass, and waste, and more particularly to a treatment device and a treatment method for recovering high-quality cracked oil from pyrolysis gas. [Background technology]

[0002] Waste plastics may contain materials such as PS (polystyrene), PP (polypropylene), PE (polyethylene), PVC (polyvinyl chloride), and PET (polyethylene terephthalate). Development of material recycling and chemical recycling, which process and reuse waste plastics containing these various resin components, is underway. In particular, chemical recycling, which uses a pyrolysis furnace to recover oil, gas, and other substances from waste plastics, is attracting increasing attention.

[0003] One example of chemical recycling is a fluidized bed furnace, whose interior is divided into a pyrolysis chamber and a media regeneration chamber by a partition wall. The media circulates between the two chambers, while waste plastics are fed into the pyrolysis chamber. The waste plastics are heated by the media in the pyrolysis chamber, and after pyrolysis, are gasified. The waste plastic residue is transported by the media to the media regeneration chamber. The waste plastic residue is burned in the media regeneration chamber, heating the media. The heated media then moves into the pyrolysis chamber, where it functions as a heat source. A fluidized bed furnace in which the media circulates within the furnace in this way is called an internal circulating fluidized bed gasification system.

[0004] Waste plastic generates pyrolysis gas through thermal decomposition. The gaseous hydrocarbons contained in this pyrolysis gas are condensed to recover cracked oil. The above-mentioned internal circulating fluidized bed gasification system is expected to be a technology that can thermally decompose waste plastic and recover cracked oil and cracked gas as pyrolysis products. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2018-537558 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the cracked oil recovered from the thermal decomposition of waste plastics can contain impurities that are undesirable for use in petroleum refining and petrochemicals. For example, by-products of thermal decomposition, such as chlorine, acid, and solids, can be contaminated into the cracked oil. More specifically, the chlorine is HCl derived from the PVC in the waste plastic, the acid is a sublimable acid derived from the PET and PVC plasticizers in the waste plastic, and the solids are polymers and coke residues produced during the thermal decomposition.

[0007] When a fluidized bed furnace is used as the pyrolysis furnace, in addition to the above-mentioned impurities generated by pyrolysis, solid materials from the fluidized bed furnace, such as fluidizing media (e.g., silica sand fine powder) and catalyst fine powder, may be mixed into the cracked oil. These impurities may reduce the quality of the cracked oil and hinder its reuse.

[0008] Therefore, the present invention provides a treatment device and a treatment method that can improve the quality of cracked oil recovered from pyrolysis gas generated by the thermal decomposition of organic matter such as waste plastics. [Means for solving the problem]

[0009] In one aspect, a treatment device is provided for recovering cracked oil from pyrolysis gas generated by thermally decomposing organic matter in a pyrolysis furnace, the treatment device comprising: a physical separation section that physically removes particles from the pyrolysis gas; and an oil recovery section that recovers cracked oil from the pyrolysis gas from which the particles have been removed, the physical separation section comprising a scrubbing dust collector that removes particles from the pyrolysis gas by spraying a cleaning medium into the pyrolysis gas.

[0010] In one aspect, the treatment device further includes an oil pump that transfers the decomposition oil recovered in the oil recovery section to the scrubbing dust collector, and the scrubbing dust collector is configured to spray the decomposition oil transferred by the oil pump onto the pyrolysis gas as the cleaning medium. In one embodiment, the scrubber is a venturi scrubber or a cyclone scrubber. In one embodiment, the physical separation section includes an oil passage structure for sending the cracked oil recovered by the scrubbing dust collector to the pyrolysis furnace. In one embodiment, the physical separation unit further includes a solid-gas separator that separates particles from the pyrolysis gas generated in the pyrolysis furnace. In one embodiment, the solid-gas separator is disposed within the pyrolysis furnace. In one aspect, the pyrolysis furnace is a fluidized bed furnace, which has the pyrolysis furnace and a media regeneration furnace through which a fluidized medium circulates, and the physical separation section includes a particle passage structure for sending the particles removed from the pyrolysis gas from the solid-gas separation device to the media regeneration furnace. In one aspect, the treatment device further includes a chemical separation unit that chemically removes impurities from the cracked oil recovered by the oil recovery unit, and the chemical separation unit includes a water supply line that supplies water to the cracked oil, an oil-water mixer that mixes the cracked oil with the water and transfers impurities in the cracked oil to the water, and an oil-water separation device connected to the oil-water mixer that separates the cracked oil from the water.

[0011] In one aspect, a treatment device is provided for recovering cracked oil from pyrolysis gas generated by thermally decomposing organic matter in a pyrolysis furnace, the treatment device comprising: an oil recovery section that recovers cracked oil from the pyrolysis gas; and a chemical separation section that chemically removes impurities from the cracked oil. The chemical separation section comprises a water supply line that supplies water to the cracked oil; an oil-water mixer that mixes the cracked oil with the water and transfers impurities in the cracked oil to the water; and an oil-water separation device connected to the oil-water mixer that separates the cracked oil from the water.

[0012] In one aspect, there is provided a treatment method for recovering cracked oil from pyrolysis gas generated by thermally decomposing organic matter in a pyrolysis furnace, the treatment method comprising: carrying out physical separation to physically remove particles from the pyrolysis gas; recovering cracked oil from the pyrolysis gas from which the particles have been removed in an oil recovery section; and directing the pyrolysis gas to a scrubbing dust collector; and removing particles from the pyrolysis gas by spraying a scrubbing medium into the pyrolysis gas in the scrubbing dust collector.

[0013] In one aspect, the decomposition oil recovered in the oil recovery section is transferred to the scrubbing dust collector, and the scrubbing dust collector sprays the decomposition oil transferred from the oil recovery section into the pyrolysis gas as the cleaning medium. In one embodiment, the scrubber is a venturi scrubber or a cyclone scrubber. In one embodiment, the physical separation further comprises sending the cracked oil recovered in the scrubber to the pyrolysis furnace. In one embodiment, the physical separation further comprises a step of separating particles from the pyrolysis gas generated in the pyrolysis furnace using a solid-gas separator. In one embodiment, the solid-gas separator is disposed within the pyrolysis furnace. In one aspect, the pyrolysis furnace is a fluidized bed furnace, which has the pyrolysis furnace and a media regeneration furnace through which a fluidized medium circulates, and the physical separation further includes a step of sending the particles removed from the pyrolysis gas by the solid-gas separation device to the media regeneration furnace. In one aspect, the treatment method further includes chemical separation to chemically remove impurities from the cracked oil recovered by the oil recovery section, and the chemical separation includes a step of supplying water to the cracked oil, mixing the cracked oil with the water to transfer impurities in the cracked oil to the water, and then separating the cracked oil from the water.

[0014] In one aspect, a treatment method for recovering cracked oil from pyrolysis gas generated by thermally decomposing organic matter in a pyrolysis furnace is provided, which comprises recovering cracked oil from the pyrolysis gas and performing chemical separation to chemically remove impurities from the cracked oil, the chemical separation including the steps of supplying water to the cracked oil, mixing the cracked oil with the water to transfer impurities in the cracked oil to the water, and then separating the cracked oil from the water. [Effects of the Invention]

[0015] The physical separation unit can remove particles from the pyrolysis gas. In particular, a physical separation unit having a solid-gas separator and a scrubber can remove particles from the pyrolysis gas in two stages. That is, the solid-gas separator can remove relatively large particles from the pyrolysis gas, and then the scrubber can remove fine particles from the pyrolysis gas. As a result, the amount of particles contained in the cracked oil recovered from the pyrolysis gas can be significantly reduced.

[0016] The chemical separation unit, which includes a water supply line, an oil-water mixer, and an oil-water separator, transfers impurities such as water-soluble substances and chlorine from the cracked oil into the water, thereby removing the impurities from the cracked oil. As a result, the amount of impurities contained in the cracked oil recovered from the pyrolysis gas can be significantly reduced.

[0017] Furthermore, a treatment device equipped with both a physical separation section and a chemical separation section can sufficiently remove impurities such as powders, water-soluble substances, and chlorine from the cracked oil, thereby significantly reducing the amount of impurities contained in the cracked oil recovered from the pyrolysis gas. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram illustrating one embodiment of a pyrolysis-type processing system for processing organic matter. [Figure 2] FIG. 1 is a schematic diagram showing another embodiment of a pyrolysis-type processing system for processing organic matter. [Figure 3]FIG. 10 is a schematic diagram showing yet another embodiment of a pyrolysis-type processing system for processing organic matter. [Figure 4] 4 is a schematic diagram showing an embodiment of a treatment device including both the physical separation section described with reference to FIG. 1 and the chemical separation section described with reference to FIG. 3. FIG. [Figure 5] FIG. 1 is a schematic diagram showing one embodiment of a pyrolysis-type processing system utilizing a fluidized bed furnace. [Figure 6] FIG. 10 is a schematic diagram showing another embodiment of a pyrolysis-type processing system using a fluidized bed furnace. [Figure 7] FIG. 10 is a schematic diagram showing yet another embodiment of a pyrolysis-type processing system using a fluidized bed furnace. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a schematic diagram showing one embodiment of a pyrolysis-type treatment system for treating organic matter. In the embodiment described below, the organic matter to be treated is waste plastic containing at least one of PVC (polyvinyl chloride), PET (polyethylene terephthalate), PS (polystyrene), PP (polypropylene), and PE (polyethylene).

[0020] As shown in Figure 1, the pyrolysis treatment system includes a pyrolysis furnace 6 that thermally decomposes waste plastics, which is an example of organic matter, and a treatment device 2 that recovers decomposed oil from the pyrolysis gas discharged from the pyrolysis furnace 6. The type of pyrolysis furnace 6 is not particularly limited, and may be, for example, a fluidized bed pyrolysis furnace, which will be described later, or a kiln pyrolysis furnace.

[0021] The treatment device 2 is equipped with a physical separation section 15 that physically removes particles from the pyrolysis gas generated by the thermal decomposition of waste plastics in the pyrolysis furnace 6, and an oil recovery section 16 that recovers cracked oil from the pyrolysis gas from which the particles have been removed. Specific examples of particles removed by the physical separation section 15 include polymers and coke residues generated during the thermal decomposition of waste plastics, fluidized bed materials (for example, fine silica sand powder), and catalyst fines.

[0022] The physical separation section 15 includes a scrubbing collector 25 that removes particles from the pyrolysis gas generated in the pyrolysis furnace 6. The scrubbing collector 25 is connected to the pyrolysis furnace 6 and disposed downstream of the pyrolysis furnace 6. The scrubbing collector 25 in this embodiment is a Venturi scrubber. More specifically, the scrubbing collector 25 includes a Venturi tube 27 connected to the gas outlet of the pyrolysis furnace 6, a cleaning medium discharge nozzle 28 having an oil outlet within the Venturi tube 27, and a cyclone collector 29 connected to the Venturi tube 27. Cracked oil already recovered from the pyrolysis gas is supplied to the cleaning medium discharge nozzle 28. That is, the cleaning medium discharge nozzle 28 is connected to the oil recovery section 16, and the cracked oil already recovered by the oil recovery section 16 is supplied to the cleaning medium discharge nozzle 28 as a cleaning medium.

[0023] The oil recovery section 16 is equipped with an oil scrubber 35 that recovers cracked oil from the pyrolysis gas, and a cracked oil storage tank 38 that stores the cracked oil discharged from the oil scrubber 35. The cracked oil in the cracked oil storage tank 38 is transferred to the scrubbing dust collector 25 by an oil pump 40. The cracked oil storage tank 38 is also equipped with an oil pump 40 that transfers the cracked oil to the cleaning medium discharge nozzle 28. The scrubbing dust collector 25 sprays the cracked oil, which has been pressurized by the oil pump 40, from the cleaning medium discharge nozzle 28 into the pyrolysis gas flowing through the Venturi tube 27.

[0024] As the pyrolysis gas flows through the Venturi tube 27, its flow velocity increases, and the pyrolysis oil sprayed from the scrubbing medium discharge nozzle 28 turns into a mist and spreads throughout the pyrolysis gas. The mist of pyrolysis oil captures particles present in the pyrolysis gas and removes them from the pyrolysis gas. The particles removed by the scrubbing dust collector 25 are, for example, particles with a diameter of 1 μm or more.

[0025] The cracked oil sprayed from the cleaning medium discharge nozzle 28 not only captures fine particles but also cools the pyrolysis gas, vaporizing the sprayed cracked oil while condensing a portion of the pyrolysis gas. The condensed cracked oil and the captured particles are collected in the cyclone collector 29. In this way, according to this embodiment, the particles in the pyrolysis gas are removed by the scrubbing dust collector 25, thereby improving the quality of the cracked oil collected in the oil scrubber 35 at the subsequent stage.

[0026] The scrubbing collector 25 in this embodiment is a venturi scrubber, but the type of scrubbing collector 25 is not particularly limited as long as the scrubbing collector 25 can remove fine particles having a diameter of 1 μm or more from the pyrolysis gas. For example, the scrubbing collector 25 may be a cyclone scrubber.

[0027] The pyrolysis gas is cooled by the scrubbing dust collector 25, for example, from 450°C to 350°C. At this time, oil components with a boiling point lower than 350°C remain in a gaseous state and flow to the downstream oil scrubber 35. On the other hand, oil components with a boiling point within the range of 350°C to 450°C are cooled and condensed by the scrubbing dust collector 25. Therefore, the cracked oil recovered by the scrubbing dust collector 25 is oil equivalent to heavy oil (i.e., heavy oil). The above operating temperature is one example, and the cooling temperature can be changed by changing the amount of cracked oil sprayed, thereby adjusting the fraction of the cracked oil recovered.

[0028] The cleaning medium of the scrubbing dust collector 25 is not limited to cracked oil; for example, a cleaning medium purchased from an external source may be sprayed. Specific examples of cleaning media include light oil introduced from an external source, high-boiling-point oil (e.g., lubricating oil with a boiling point of 450°C or higher), and water. Furthermore, it is not necessary to cool the pyrolysis gas; for example, by spraying a cleaning medium that does not vaporize at the temperature of the pyrolysis gas at the temperature of the pyrolysis gas, particles can be removed without condensing the pyrolysis gas.

[0029] The physical separation section 15 is equipped with an oil passage structure 43 for sending the cracked oil recovered by the scrubber 25 to the pyrolysis furnace 6. This oil passage structure 43 extends from a heavy oil tank 45 connected to the bottom of the cyclone collector 29 to the pyrolysis furnace 6. The specific structure and shape of the oil passage structure 43 are not particularly limited as long as it has oil passages that allow the cracked oil to pass through. Since the recovered cracked oil contains fine particles, a separation device for removing these fine particles from the cracked oil may be provided in the oil passage structure 43.

[0030] The cracked oil (heavy oil) collected at the bottom of the scrubber dust collector 25 is temporarily stored in a heavy oil tank 45, and then sent from the heavy oil tank 45 through an oil passage structure 43 into the thermal cracking furnace 6. The physical separation section 15 has a liquid level sensor 46 that detects the liquid level of the cracked oil accumulated in the heavy oil tank 45, and an on-off valve 47 that opens and closes based on the liquid level position output from the liquid level sensor 46. The on-off valve 47 is attached to the oil passage structure 43.

[0031] The on-off valve 47 is configured to open when the liquid level of the cracked oil in the heavy oil tank 45 is higher than a predetermined level. The on-off valve 47 is an actuator-driven valve such as an electric valve or a solenoid valve. When the on-off valve 47 is open, the cracked oil is sent from the heavy oil tank 45 through the oil passage structure 43 into the thermal cracking furnace 6. The cracked oil (heavy oil) returned to the thermal cracking furnace 6 is thermally cracked again in the thermal cracking furnace 6. Most of the pyrolyzed cracked oil remains in a gaseous state and passes through the scrubbing dust collector 25, while the remainder is condensed again to form cracked oil (heavy oil). In this way, the heavy oil of the cracked oil generated from the waste plastic is recovered by the scrubbing dust collector 25, and the oil scrubber 35 can recover oil components with lower boiling points than the heavy oil (diesel, kerosene, gasoline, etc.).

[0032] The oil scrubber 35 is arranged downstream of the scrubbing dust collector 25. The oil scrubber 35 is connected to the scrubbing dust collector 25, and the pyrolysis gas from which particles have been removed by the scrubbing dust collector 25 is led to the oil scrubber 35. In this embodiment, the oil scrubber 35 is connected downstream of the cyclone collector 29 of the scrubbing dust collector 25.

[0033] The oil scrubber 35 sprays cracked oil already recovered from the pyrolysis gas into the pyrolysis gas, thereby cooling the pyrolysis gas and condensing the gaseous cracked oil (hydrocarbons) in the pyrolysis gas. Both the condensed cracked oil and the sprayed cracked oil are discharged from the oil scrubber 35 and stored in a cracked oil storage tank 38. The specific configuration of the oil scrubber 35 to be used is not particularly limited, and a known oil scrubber can be used. For example, a washing tower having a gas passage formed therein and spray nozzles that spray oil into the gas flowing through the passage can be used as the oil scrubber 35.

[0034] The oil scrubber 35 further cools the pyrolysis gas cooled by the scrubber 25 by spraying cracked oil onto the pyrolysis gas. For example, the pyrolysis gas is cooled from 450°C to 350°C by the scrubber 25, and then cooled from 350°C to 100°C by the oil scrubber 35. Therefore, in the oil scrubber 35, oil components with boiling points in the range of 350°C to 100°C are condensed and recovered.

[0035] The oil recovery section 16 further includes a water scrubber 50 disposed downstream of the oil scrubber 35, and an oil-water separator 51 that separates the cracked oil from the mixture of cracked oil and water discharged from the water scrubber 50. The water scrubber 50 sprays water onto the pyrolysis gas passing through it to further cool the pyrolysis gas. In this embodiment, the water scrubber 50 sprays alkaline water onto the pyrolysis gas. The pyrolysis gas is cooled by contact with water (alkaline water in this embodiment). For example, the pyrolysis gas is cooled from 100°C to 40°C by the water scrubber 50. Therefore, the water scrubber 50 condenses and recovers oil components and water vapor having boiling points within the range of 100°C to 40°C.

[0036] The mixture of cracked oil and water is discharged from the water scrubber 50 and sent to the oil-water separator 51. The oil-water separator 51 is configured to separate the cracked oil from the water. The specific configuration of the oil-water separator 51 is not particularly limited, but for example, a coalescer or a sedimentation tank can be used as the oil-water separator 51. The cracked oil separated by the oil-water separator 51 is sent to the cracked oil storage tank 38 and stored therein.

[0037] As described above, according to this embodiment, the cracked oil contained in the pyrolysis gas is recovered by the oil scrubber 35 and the water scrubber 50, thereby improving the overall yield of cracked oil. The specific configuration of the water scrubber 50 to be used is not particularly limited, and any known water scrubber can be used. For example, a washing tower having a gas passage formed therein and spray nozzles that spray water onto the gas flowing through the passage can be used as the water scrubber 50.

[0038] The oil scrubber 35 and water scrubber 50 described above are examples of condensers that condense gaseous cracked oil (hydrocarbons) in the pyrolysis gas. The condenser may be a multi-stage condenser as in this embodiment, or a single-stage condenser. The cooling form of the condenser may be direct cooling or indirect cooling.

[0039] Next, another embodiment of the pyrolysis-type processing system will be described with reference to Fig. 2. The configuration and operation of this embodiment, which will not be specifically described, are the same as those of the embodiment described with reference to Fig. 1, and therefore, redundant description will be omitted.

[0040] The physical separation section 15 includes a solid-gas separator 18 that separates particles from the pyrolysis gas generated in the pyrolysis furnace 6, and a scrubbing dust collector 25 that further removes particles from the pyrolysis gas by spraying cracked oil onto the pyrolysis gas from which the particles have been separated. The scrubbing dust collector 25 has the same configuration as the scrubbing dust collector 25 of the embodiment described with reference to FIG. 1. The solid-gas separator 18 is preferably placed inside the pyrolysis furnace 6 to prevent a temperature drop due to heat radiation, but may also be placed outside the pyrolysis furnace 6. In this embodiment, the solid-gas separator 18 is a cyclone-type solid-gas separator that separates particles from the pyrolysis gas by centrifugal force.

[0041] Pyrolysis gas generated by the thermal decomposition of waste plastics in the pyrolysis furnace 6 enters the solid-gas separator 18 from the upper inlet 18a and forms a swirling flow within the solid-gas separator 18. Particles contained in the pyrolysis gas are separated from the pyrolysis gas by centrifugal force. Particles removed by the solid-gas separator 18 are, for example, particles with a diameter of 10 μm or more. The particles separated from the pyrolysis gas are collected at the bottom of the solid-gas separator 18.

[0042] The physical separation section 15 is equipped with a particle passage structure 19 for sending particles removed from the pyrolysis gas from the solid-gas separator 18 to the outside of the pyrolysis furnace 6. This particle passage structure 19 extends from the bottom of the solid-gas separator 18 to the outside of the pyrolysis furnace 6. The particles collected at the bottom of the solid-gas separator 18 are discharged from the solid-gas separator 18 through the particle passage structure 19 due to their own weight. The specific structure and shape of the particle passage structure 19 are not particularly limited as long as it has particle passages that allow particles to pass through.

[0043] In one embodiment, the particle passage structure 19 may extend from the bottom of the solid-gas separator 18 into the interior of the pyrolysis furnace 6. That is, particles collected at the bottom of the solid-gas separator 18 may be returned to the pyrolysis furnace 6 through the particle passage structure 19.

[0044] The scrubbing dust collector 25 is disposed downstream of the solid-gas separator 18. The scrubbing dust collector 25 is connected to the solid-gas separator 18, and the pyrolysis gas from which particles have been removed by the solid-gas separator 18 is led to the scrubbing dust collector 25. More specifically, the venturi tube 27 of the scrubbing dust collector 25 is connected to the gas outlet of the solid-gas separator 18. The configuration and arrangement of the scrubbing dust collector 25 not specifically described are the same as those in the embodiment described with reference to Fig. 1, so duplicated description will be omitted.

[0045] The scrubbing collector 25 in this embodiment is a venturi scrubber, but the type of the scrubbing collector 25 is not particularly limited as long as the scrubbing collector 25 can remove particles from the pyrolysis gas that are smaller in size than the particles removed by the solid-gas separator 18. For example, the scrubbing collector 25 may be a cyclone scrubber.

[0046] According to this embodiment, particles in the pyrolysis gas are removed in two stages by the solid-gas separator 18 and the scrubber 25. That is, the solid-gas separator 18 removes relatively large particles from the pyrolysis gas, and then the scrubber 25 removes fine particles from the pyrolysis gas. As a result, the quality of the cracked oil recovered in the oil scrubber 35 at the subsequent stage can be improved. In particular, the physical separation unit 15 equipped with both the solid-gas separator 18 and the scrubber 25 is suitable when the particle concentration in the pyrolysis gas is high.

[0047] Next, another embodiment of the pyrolysis-type processing system will be described with reference to Fig. 3. The configuration and operation of this embodiment, which will not be specifically described, are the same as those of the embodiment described with reference to Fig. 1, and therefore, redundant description will be omitted.

[0048] The waste plastics to be treated may contain both PVC (polyvinyl chloride) and PET (polyethylene terephthalate). When PVC is thermally decomposed in the pyrolysis furnace 6, it generates HCl (hydrogen chloride), which corrodes downstream equipment and deteriorates the quality of the decomposition oil recovered from the waste plastic. When PET is thermally decomposed in the pyrolysis furnace 6, it generates benzoic acid and terephthalic acid. Both of these acids sublimate and accumulate downstream, causing fouling and corrosion of downstream equipment and deterioration of the quality of the decomposition oil due to acid contamination (crystal precipitation).

[0049] Therefore, in this embodiment, impurities such as HCl derived from PVC and sublimable acids derived from PET are chemically removed from the cracked oil. As shown in Figure 3, the treatment device 2 that recovers cracked oil from the pyrolysis gas discharged from the pyrolysis furnace 6 includes an oil recovery section 16 that recovers the cracked oil from the pyrolysis gas and a chemical separation section 60 that chemically removes impurities from the cracked oil recovered by the oil recovery section 16. In this embodiment, the physical separation section 15 (solid-gas separator 18 and scrubber 25) is not provided. The oil recovery section 16 has the same configuration as the oil recovery section 16 in the embodiment shown in Figure 1, so a duplicated description will be omitted.

[0050] The chemical separation unit 60 includes a water supply line 61 that supplies water to the cracked oil, an oil-water mixer 64 that mixes the cracked oil with water and transfers impurities in the cracked oil to the water, and an oil-water separator 66 that is connected to the oil-water mixer 64 and separates the cracked oil from the water. Specific examples of impurities removed by the chemical separation unit 60 include PVC-derived HCl and PET-derived sublimable acid crystals that are generated during the thermal decomposition of waste plastic. Specific examples of water supplied from the water supply line 61 include steam condensate, pure water, and alkaline water. In this embodiment, alkaline water is used as the water supplied from the water supply line 61.

[0051] The oil-water mixer 64 is connected to the cracked oil reservoir 38 of the oil recovery section 16. An oil pump 40 is installed in the cracked oil reservoir 38, and the cracked oil is transferred from the cracked oil reservoir 38 to the oil-water mixer 64. A water supply line 61 is connected upstream of the oil-water mixer 64, and water is sent to the oil-water mixer 64 through the water supply line 61. In this embodiment, the water is alkaline water discharged from the water scrubber 50. That is, the water supply line 61 is connected to the oil-water separator 51 connected to the water scrubber 50, and the alkaline water separated from the cracked oil by the oil-water separator 51 is sent to the oil-water mixer 64 through the water supply line 61. In one embodiment, the water supply line 61 may be connected to an alkaline water supply source (not shown). In other embodiments, the water supply line 61 may be connected to a pure water supply source or a steam condensate supply source (not shown).

[0052] The cracked oil recovered by the oil recovery section 16, more specifically the oil scrubber 35 and the water scrubber 50, is mixed with alkaline water by the oil-water mixer 64. Water-soluble powders (e.g., sublimable acid crystals derived from PET) and HCl contained in the cracked oil move to the alkaline water and are dissolved in the alkaline water.

[0053] The mixture of cracked oil and alkaline water output from the oil-water mixer 64 is sent to the oil-water separator 66, where the cracked oil is separated from the alkaline water (including impurities). As described above, water-soluble powders and impurities such as HCl contained in the cracked oil are dissolved in the alkaline water, so these impurities are separated from the cracked oil along with the alkaline water. Therefore, the cracked oil extracted from the oil-water separator 66 is high-quality oil. The oil-water separator 66 is not particularly limited as long as it has a structure capable of separating the cracked oil from the alkaline water, but for example, a coalescer or a sedimentation tank can be used as the oil-water separator 66.

[0054] According to this embodiment, the chemical separation unit 60, which includes the water supply line 61, oil-water mixer 64, and oil-water separator 66, can remove impurities such as water-soluble substances and chlorine from the cracked oil by transferring them to water (alkaline water in this embodiment). As a result, the amount of impurities contained in the cracked oil recovered from the pyrolysis gas can be significantly reduced.

[0055] As mentioned above, PVC and PET contained in waste plastics generate chlorine and sublimable acids during thermal decomposition, which degrades the quality of the recovered decomposition oil. To solve this problem, slaked lime can be added to the waste plastics before they are fed into the pyrolysis furnace 6. By mixing the waste plastics with the slaked lime and heating them, the PVC is desalted and the PET is hydrolyzed. Specifically, by heating the PVC, the chlorine contained in the PVC is thermally separated into HCl (hydrogen chloride). The generated HCl is dry-processed with slaked lime, and the chlorine in the HCl is fixed to the slaked lime as calcium salt (CaCl). Furthermore, heating the PET with slaked lime produces calcium terephthalate. This calcium terephthalate is thermally decomposed in the pyrolysis furnace 6, suppressing the production of sublimable benzoic acid and terephthalic acid, thereby improving the yield of decomposition oil (especially benzene).

[0056] On the other hand, when processing using slaked lime, fine slaked lime powder (Ca(OH)2) and particles of by-product calcium salts (CaCl2, CaCO3) can be mixed into the cracked oil recovered from the pyrolysis gas. HCl from PVC that was not fixed by the slaked lime can also be mixed into the cracked oil. Furthermore, some of the ester compounds contained in PVC plasticizers and PET produce sublimable benzoic acid and terephthalic acid without being hydrolyzed, and these sublimable acids can be mixed into the cracked oil as powder (crystals) when it is recovered from the pyrolysis gas.

[0057] Even in such cases, the chemical separation unit 60 shown in Figure 3 can separate the cracked oil from the pyrolysis gas by mixing fine powder of slaked lime (Ca(OH)), powder of Ca salts (CaCl, CaCO), HCl derived from PVC, and powder of sublimable acid derived from PET with water (e.g., alkaline water). As a result, the quality of the cracked oil recovered from the pyrolysis gas can be improved.

[0058] FIG. 4 is a schematic diagram illustrating one embodiment of a processing apparatus 2 equipped with both the physical separation unit 15 described with reference to FIG. 2 and the chemical separation unit 60 described with reference to FIG. 3. As shown in FIG. 4, the chemical separation unit 60 is disposed downstream of the physical separation unit 15. The physical separation unit 15 removes impurities such as particles from the pyrolysis gas, and then the chemical separation unit 60 removes impurities such as water-soluble powders and chlorine from the cracked oil recovered from the pyrolysis gas. The processing apparatus 2 equipped with both the physical separation unit 15 and the chemical separation unit 60 can sufficiently remove impurities such as particles, water-soluble substances, and chlorine from the cracked oil. As a result, the amount of impurities contained in the cracked oil recovered from the pyrolysis gas can be significantly reduced.

[0059] In one embodiment, the processing device 2 may include the physical separation section 15 described with reference to FIG. 1 and the chemical separation section 60 described with reference to FIG.

[0060] 5 is a schematic diagram showing one embodiment of a pyrolysis-type processing system using a fluidized-bed furnace. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to FIG. 2, and therefore, redundant description will be omitted.

[0061] As shown in Fig. 5, the pyrolysis treatment system includes a fluidized bed furnace 1 that thermally decomposes and further combusts waste plastics, which are an example of organic matter, and a treatment device 2 that recovers decomposition oil from the pyrolysis gas discharged from the fluidized bed furnace 1. The fluidized bed furnace 1 includes a pyrolysis furnace 6 that thermally decomposes the waste plastics to produce pyrolysis gas containing pyrolysis products such as hydrocarbons, and a media regeneration furnace 7 that combusts the residue of the pyrolyzed waste plastics. The pyrolysis furnace 6 in the embodiment shown in Fig. 5 corresponds to the pyrolysis furnace 6 in the embodiments shown in Figs. 1 to 4.

[0062] The pyrolysis furnace 6 and the media regeneration furnace 7 are formed within a single fluidized bed furnace 1. That is, the interior of the fluidized bed furnace 1 is divided into the pyrolysis furnace 6 and the media regeneration furnace 7 by a partition wall 10. The overall shape of the fluidized bed furnace 1 is not particularly limited, but may be, for example, cylindrical or rectangular. A fluidized medium (e.g., silica sand) is contained within the pyrolysis furnace 6 and the media regeneration furnace 7. A fluidizing gas G is supplied to the pyrolysis furnace 6 and the media regeneration furnace 7 to fluidize the fluidized medium. Waste plastic, which is the raw material, is supplied into the pyrolysis furnace 6 by a raw material supply device (not shown).

[0063] The bed material circulates between the pyrolysis furnace 6 and the media regeneration furnace 7, while waste plastics are fed into the pyrolysis furnace 6. The waste plastics are heated by the bed material in the pyrolysis furnace 6, and after pyrolysis are gasified. The waste plastic residue is transported by the bed material to the media regeneration furnace 7. The waste plastic residue is burned in the media regeneration furnace 7, heating the bed material. The heated bed material moves into the pyrolysis furnace 6, where it functions as a heat source. A fluidized bed furnace 1 in which the bed material circulates within the furnace in this way is called an internal circulating fluidized bed gasification system.

[0064] The treatment device 2 includes the physical separation unit 15 and oil recovery unit 16 described with reference to Fig. 2. That is, the physical separation unit 15 includes both a solid-gas separator 18 and a scrubber 25. This is because the pyrolysis gas discharged from the pyrolysis furnace 6 constituting the fluidized-bed furnace 1 contains a high concentration of particles.

[0065] The physical separation section 15 is equipped with a particle passage structure 19 for sending particles removed from the pyrolysis gas from the solid-gas separator 18 to the media regeneration furnace 7 of the fluidized bed furnace 1. This particle passage structure 19 extends from the bottom of the solid-gas separator 18 to the media regeneration furnace 7. The particles collected at the bottom of the solid-gas separator 18 are sent by their own weight through the particle passage structure 19 into the media regeneration furnace 7, where they are combusted. The specific structure and shape of the particle passage structure 19 are not particularly limited as long as it has particle passages that allow the particles to pass through.

[0066] In one embodiment, the particle passage structure 19 may extend from the bottom of the solid-gas separator 18 into the interior of the pyrolysis furnace 6. That is, particles collected at the bottom of the solid-gas separator 18 may be returned to the pyrolysis furnace 6 through the particle passage structure 19.

[0067] Figure 6 is a schematic diagram showing another embodiment of a pyrolysis-type processing system using a fluidized-bed furnace. The configuration and operation of this embodiment, which are not specifically described, are the same as those of the embodiment described with reference to Figure 5, and therefore, redundant description will be omitted. The pyrolysis-type processing system of the embodiment shown in Figure 6 includes the fluidized-bed furnace 1 described with reference to Figure 5 and a processing device 2 that recovers cracked oil from the pyrolysis gas discharged from the fluidized-bed furnace 1.

[0068] The treatment device 2 includes an oil recovery section 16 that recovers cracked oil from the pyrolysis gas, and a chemical separation section 60 that chemically removes impurities from the cracked oil recovered by the oil recovery section 16. In this embodiment, the physical separation section 15 (solid-gas separation device 18 and scrubbing dust collector 25) shown in Fig. 5 is not provided. The oil recovery section 16 and the chemical separation section 60 have the same configuration as the oil recovery section 16 and the chemical separation section 60 in the embodiment shown in Fig. 3, so a duplicated description thereof will be omitted.

[0069] Figure 7 is a schematic diagram showing yet another embodiment of a pyrolysis-type processing system using a fluidized-bed furnace. The configuration and operation of this embodiment, which will not be specifically described, are the same as those of the embodiment described with reference to Figures 5 and 6, and therefore, redundant description will be omitted. As shown in Figure 7, the pyrolysis-type processing system includes the fluidized-bed furnace 1 described with reference to Figure 5 and a processing device 2 that recovers cracked oil from the pyrolysis gas discharged from the fluidized-bed furnace 1.

[0070] The processing device 2 includes both the physical separation unit 15 described with reference to Fig. 2 and the chemical separation unit 60 described with reference to Fig. 3. That is, the processing device 2 includes the physical separation unit 15 that physically removes particles from the pyrolysis gas generated by pyrolyzing waste plastics in the pyrolysis furnace 6, the oil recovery unit 16 that recovers cracked oil from the pyrolysis gas from which the particles have been removed, and the chemical separation unit 60 that chemically removes impurities from the cracked oil recovered by the oil recovery unit 16.

[0071] The chemical separation unit 60 is disposed downstream of the physical separation unit 15. The physical separation unit 15 removes impurities such as particles from the pyrolysis gas, and then the chemical separation unit 60 removes impurities such as water-soluble powders and chlorine from the cracked oil recovered from the pyrolysis gas. The treatment device 2 equipped with both the physical separation unit 15 and the chemical separation unit 60 can sufficiently remove impurities such as particles, water-soluble substances, and chlorine from the cracked oil. As a result, the amount of impurities contained in the cracked oil recovered from the pyrolysis gas can be significantly reduced.

[0072] The above-described embodiments have been described for the purpose of enabling a person of ordinary skill in the art to practice the present invention. Various modifications of the above-described embodiments would be obvious to a person skilled in the art, and the technical concept of the present invention may be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is to be interpreted in the broadest scope in accordance with the technical concept defined by the claims. [Explanation of symbols]

[0073] 1 Fluidized bed furnace 2 Processing equipment 6 Pyrolysis furnace 7 Media regeneration furnace 10 Partition Wall 15 Physical separation section 16 Oil recovery section 18 Solid-gas separator 19 Particle passage structure 25 Cleaning dust collector 27 Venturi tube 28 Cleaning medium discharge nozzle 29 Cyclone collector 35 Oil Scrubber 38 Cracking oil storage tank 40 Oil pump 43 Oil passage structure 45 Heavy oil tank 46 Liquid level sensor 47 On-off valve 50 Water Scrubber 51 Oil-water separator 60 Chemical separation section 61 Water Supply Line 64 Oil-water mixer 66 Oil-water separator

Claims

1. A treatment device for recovering cracked oil from pyrolysis gas generated by pyrolyzing organic matter in a pyrolysis furnace, a physical separation section for physically removing particles from the pyrolysis gas; an oil recovery unit that recovers cracked oil from the pyrolysis gas from which the particles have been removed; the physical separation unit includes a scrubbing dust collector that removes particles from the pyrolysis gas by spraying a cleaning medium into the pyrolysis gas, and a solid-gas separator that separates particles from the pyrolysis gas generated in the pyrolysis furnace; the solid-gas separator is disposed within the pyrolysis furnace; The pyrolysis furnace is a fluidized bed pyrolysis furnace, The fluidized bed furnace has the pyrolysis furnace and a medium regeneration furnace through which a fluidized bed medium circulates, the physical separation unit includes a particle passage structure for transporting the particles removed from the pyrolysis gas from the solid-gas separation device to the media regeneration furnace; The processing apparatus wherein the particle passage structure extends from the pyrolysis furnace to the media regeneration furnace.

2. The treatment device further includes an oil pump that transfers the decomposed oil recovered in the oil recovery unit to the scrubber dust collector, The treatment device according to claim 1 , wherein the scrubbing dust collector is configured to spray the cracked oil transferred by the oil pump as the cleaning medium onto the pyrolysis gas.

3. The treatment device according to claim 1 or 2, wherein the scrubbing dust collector is a venturi scrubber or a cyclone scrubber.

4. The treatment device according to claim 1 , wherein the physical separation unit includes an oil passage structure for sending the cracked oil collected by the scrubbing dust collector to the thermal cracking furnace.

5. The treatment device further includes a chemical separation unit that chemically removes impurities from the cracked oil recovered by the oil recovery unit, The chemical separation unit a water supply line for supplying water to the cracked oil; an oil-water mixer that mixes the cracked oil with the water to transfer impurities in the cracked oil to the water; The treatment device according to claim 1 , further comprising an oil-water separator connected to the oil-water mixer for separating the cracked oil from the water.

6. A processing method for recovering cracked oil from pyrolysis gas generated by pyrolyzing organic matter in a pyrolysis furnace, comprising: performing a physical separation to physically remove particles from the pyrolysis gas; recovering cracked oil from the pyrolysis gas from which the particles have been removed by an oil recovery section; The physical separation includes separating particles from the pyrolysis gas generated in the pyrolysis furnace using a solid-gas separator, and further introducing the pyrolysis gas into a scrubbing dust collector, and removing particles from the pyrolysis gas by spraying a scrubbing medium into the pyrolysis gas in the scrubbing dust collector; the solid-gas separator is disposed within the pyrolysis furnace; The pyrolysis furnace is a fluidized bed pyrolysis furnace, The fluidized bed furnace has the pyrolysis furnace and a medium regeneration furnace through which a fluidized bed medium circulates, The physical separation further includes a step of sending the particles removed from the pyrolysis gas by the solid-gas separator through a particle passage structure to the media regeneration furnace; The method of the present invention, wherein the particle passage structure extends from the pyrolysis furnace to the media regeneration furnace.

7. The decomposed oil recovered in the oil recovery section is transferred to the scrubbing dust collector, The treatment method according to claim 6, wherein the scrubbing dust collector sprays the cracked oil transferred from the oil recovery section as the cleaning medium onto the pyrolysis gas.

8. 8. The treatment method according to claim 6 or 7, wherein the scrubbing dust collector is a venturi scrubber or a cyclone scrubber.

9. 9. The method according to claim 6, wherein the physical separation further comprises a step of sending the cracked oil recovered in the scrubber to the pyrolysis furnace.

10. The processing method further includes chemical separation for chemically removing impurities from the cracked oil recovered by the oil recovery unit, The chemical separation comprises: Supplying water to the cracked oil; The cracked oil and the water are mixed to transfer impurities in the cracked oil to the water, and then The treatment method according to any one of claims 6 to 9, further comprising a step of separating the cracked oil from the water.

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