JP2007161783A - Continuous volume-reduction system for polymer waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous volume-reduction system for polymer waste realizing a large capacity by the improvement in the thermal decomposition efficiency and treating speed. <P>SOLUTION: The continuous volume-reduction system 1 for polymer waste is provided with a circulation system 2 to perform the thermal decomposition of polymer waste with a circulating oxygen-free gas, an air-shielded continuous charging apparatus 3 to charge the polymer waste to the circulation system 2 in oxygen-free state, an air-shielded continuous discharging apparatus 4 to discharge the heat-decomposed polymer waste from the circulation system in oxygen-free state, and an exhaust gas treating apparatus 24 to clean and discharge the excess gas in the circulation system. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a system for continuously pyrolyzing polymer waste to reduce the volume.

  FIG. 2 is a schematic diagram showing the configuration of a conventional system for thermally decomposing polymer waste. As shown in FIG. 2, the conventional system mainly includes a pretreatment device 50 and a pyrolysis oil converting device 60.

  In the pretreatment device 50, the raw material 40 that is a polymer waste is pretreated through the crusher 51, the magnetic separator 52, the water washer 53, the dryer 54, and the deaerator 55 in this order. More specifically, the raw material 40 is roughly crushed, finely crushed, separated and separated by a crusher 51, iron and other impurities are removed by a magnetic separator 52, and earth and sand are removed by a water washing machine 53. Moisture is removed by the dryer 54, and finally the hydrogen chloride gas is removed by the deaerator 55 due to the inclusion of vinyl chloride or the like.

  The polymer waste after such pretreatment is then sent to the pyrolysis oil converting device 60. In the pyrolysis oil converting apparatus 60, first, the polymer waste is put into the heating furnace 61, and is heated and melted by the heat of the burner 62 to about 250 degrees through the furnace wall. The molten polymer waste is sent to the pyrolysis furnace 63, where it is further heated by the heat of the burner 62 through the furnace wall at a high temperature and pyrolyzed. During this pyrolysis, pyrolysis gas is generated from the polymer waste.

  The generated pyrolysis gas is cooled by the condenser 64 to condense the oil, and this oil is recovered in the oil recovery tank 65. The recovered oil is then stored in the recovered oil storage tank 66. Further, since the residual gas after the oil is recovered is flammable, it is used as an auxiliary fuel for the burner 62.

  In the system shown in FIG. 2, the melt in both the furnaces 61 and 63 is circulated by the circulation pump 67 in order to prevent stagnation of the melt in the heating furnace 61 and the pyrolysis furnace 63. In addition, the exhaust gas treatment device 68 shown in FIG. 2 releases the low molecular weight gas generated when the polymer waste is heated in the heating furnace 61 to the atmosphere after cooling, dust removal and washing. Is.

  Incidentally, the conventional polymer waste treatment system as shown in FIG. 2 is uneconomical because of many pretreatment steps. In addition, in the pyrolysis furnace, polymer waste must be heated through the furnace wall, and because the waste is polymer-based and has low thermal conductivity, sufficient pyrolysis is not performed. There is also a problem of efficiency that pyrolysis takes a long time. The fact that the polymer waste is highly viscous and difficult to cause convection is also one of the causes of the long time required for thermal decomposition. For this reason, it takes a long time from the introduction of polymer waste as a raw material to the completion of thermal decomposition, and the energy consumption increases, making it difficult to increase the size of the system. .

  In addition, the pyrolysis gas component of polymer wastes varies in carbon number depending on the temperature during pyrolysis, and the pyrolysis gas has a smaller carbon number as the pyrolysis proceeds at a higher temperature, and the range of variation is narrower. Thus, a relatively uniform oil can be recovered. However, in the case of a conventional polymer waste treatment system, heating of polymer waste in a pyrolysis furnace is inefficient, so if it is attempted to pyrolyze at a high temperature, overheating tends to occur. It will cause damage. Moreover, in the said system heated via a furnace wall, the caulking which inhibits heat transfer tends to produce on a wall surface, and it is difficult to improve the efficiency of thermal decomposition.

  Accordingly, an object of the present invention is to provide a continuous polymer waste volume reducing system capable of solving the above-mentioned conventional problems when processing polymer waste.

  The present invention has been made in view of the above-described circumstances, and the continuous polymer waste volume reduction system according to the present invention is a circulation in which pyrolysis treatment is performed by an oxygen-free gas that circulates polymer waste. System, an air-blocking continuous input device for sending polymer waste into the circulation system in an oxygen-free state, and an air-blocking continuous discharge for discharging the polymer waste after pyrolysis to the outside of the circulation system in an oxygen-free state And an exhaust gas treatment device that purifies and discharges surplus gas in the circulation system, and the circulation system is a heat that thermally decomposes the polymer waste fed by the air shut-off continuous input device with an oxygen-free gas. A cracking furnace, a condenser for recovering oil by cooling a pyrolysis gas generated during pyrolysis of polymer waste in the pyrolysis furnace, and an oxygen-free pyrolysis gas after the oil is recovered by the condenser Heat exchange that heats up as gas When the oxygen-free gas, at least the pyrolysis furnace, a capacitor, and a circulation flow path through a heat exchanger to circulate in the system.

  By adopting such a configuration, it can be thermally decomposed without requiring a lot of pretreatment, and exhibits excellent effects such as improved thermal decomposition efficiency and improved processing speed in the circulation system. It is possible to increase the size of the system (that is, increase the capacity).

  The surplus gas in the circulation system may be used as a heat source for the heat exchanger. By adopting such a configuration, it becomes possible to reuse the surplus gas, so that the economic efficiency of the system is improved.

  Moreover, you may further provide the introduction gas production | generation apparatus which produces | generates the nitrogen or water vapor | steam introduced into the said circulation flow path so that the inside of the said circulation system may be made an oxygen-free state at the time of an operation start and / or an operation stop. By adopting such a configuration, the safety of the system can be improved by eliminating combustible gas.

  INDUSTRIAL APPLICABILITY The present invention can provide a continuous polymer waste volume reducing system capable of realizing a large capacity by improving thermal decomposition efficiency and processing speed.

  Hereinafter, a continuous polymer waste volume reducing system according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing an overall configuration of a continuous polymer waste volume reduction system (hereinafter simply referred to as “volume reduction system”) according to an embodiment of the present invention. As shown in FIG. 1, a volume reduction system 1 according to the present embodiment includes a circulation system 2 for thermally decomposing charged polymer waste with a circulation gas to reduce the volume, and to the circulation system 2. Air shut-off continuous input device 3 that can continuously input polymer waste in an oxygen-free state, and continuously discharge the polymer waste after volume reduction from the circulation system 2 in an oxygen-free state It is mainly provided with an air shut-off continuous discharge device 4 that can be used.

  The circulation system 2 includes a pyrolysis furnace 10 that stores the polymer waste sent into the system by the air shut-off continuous charging device 3 and thermally decomposes it. The pyrolysis furnace 10 pyrolyzes polymer waste with a high-temperature oxygen-free gas circulating in the system, and generates pyrolysis gas accordingly. The pyrolyzed polymer waste is discharged from the pyrolysis furnace 10 (that is, from the circulation system 2) by the air shut-off continuous discharge device 4.

  A condenser 12 connected to the pyrolysis furnace 10 by a flow path 11 is provided on the downstream side of the pyrolysis furnace 10 in the circulation system 2. The capacitor 12 cools the pyrolysis gas generated in the pyrolysis furnace 10 and recovers oil. Below the condenser 12, an oil collecting pot 13 for temporarily storing the oil collected by the condenser 12 is disposed, and the oil stored in the oil collecting pot 13 is separated after the oil is sent to the oil collecting pot 13. The remaining moisture is separated in the tank 14.

  In the capacitor 12, an oxygen-free gas that is a residual gas is generated simultaneously with the recovery of the oil component described above. A flow path 15 for circulating the oxygen-free gas into the system extends from the condenser 12 in the downstream direction of the system, and the flow path 15 is connected to a heat exchanger 17 via a circulation blower 16. . The heat exchanger 17 raises the oxygen-free gas sent through the flow path 15 to a high temperature. The oxygen-free gas that has become a high temperature is a blowing pressure generated in the circulation blower 16 and is supplied from the heat exchanger 17 to the system. It is sent to the pyrolysis furnace 10 through the flow path 18 extending in the downstream direction, and the polymer waste in the pyrolysis furnace 10 is pyrolyzed. The oxygen-free gas after being subjected to pyrolysis is sent again to the capacitor 12 through the flow path 11 together with the pyrolysis gas generated by pyrolysis.

  On the other hand, since pyrolysis gas is always generated in the pyrolysis furnace 10 with pyrolysis, surplus gas exceeding the amount necessary for circulation in the system is generated. This surplus gas is sent to the hot stove 21 through a flow path 20 extending from the pyrolysis furnace 10. The hot stove 21 is burned with a heating power of about 800 degrees by a burner 22 that mainly uses kerosene or oil collected by the condenser 12 as fuel, and is sent to the heat exchanger 17. As the fuel for the burner 22, surplus gas exceeding the circulating amount in the system may be used in addition to the kerosene and oil. That is, the pyrolysis gas generated by pyrolysis of the polymer waste is circulated in the circulation system 2 as a kind of oxygen-free gas by the blowing pressure of the circulation blower 16, but the hydrocarbon conversion carbon number is 3 or less. These components and hydrogen gas gradually increase as the pyrolysis of the polymer waste as a surplus gas. This surplus gas can be reused as fuel for the burner 22.

  The high-temperature surplus gas sent to the heat exchanger 17 flows through the heat exchanger 17 in a state of being hermetically partitioned from the oxygen-free gas sent from the condenser 12 to the heat exchanger 17. The oxygen-free gas from the capacitor 12 is heated. The high-temperature surplus gas is sent to the exhaust gas treatment device 24 by the exhaust blower 23 in a state where the oxygen-free gas sent from the condenser 12 is heated in the heat exchanger 17 and reduced in temperature to about 600 degrees.

A caustic soda injection device 25 is connected to the exhaust gas treatment device 24. The caustic soda injection device 25 injects caustic soda into the circulating water supplied from the circulating water pump 26, and the mixed water after injection is jetted from the top of the exhaust pipe (tank) 27 of the exhaust gas treatment device 24. Be injected. As a result, the inside of the exhaust gas treatment device 24 is cleaned, and at the same time, the exhaust gas is discharged from the exhaust tube 25 into the atmosphere after the components such as dust, HCl and SO ₂ contained therein are removed.

  Further, the volume reduction system 1 according to the present embodiment includes a nitrogen gas generator 30. The nitrogen gas generator 30 is used to change the inside of the circulation system 2 from air containing oxygen to a nitrogen atmosphere at the start of operation and / or at the end of operation (stop). That is, the nitrogen generated by the nitrogen gas generator 30 is introduced into the system and circulated, thereby bringing the entire system into a nitrogen atmosphere (that is, an oxygen-free state). Note that water vapor may be used instead of nitrogen gas. In this case, the volume reduction system 1 may be provided with a water vapor generator (not shown) instead of the nitrogen gas generator 30.

  The present invention can be applied to a volume reduction system for polymer waste.

It is drawing which shows the whole structure of the polymeric waste volume reduction system which concerns on embodiment of this invention. It is a schematic diagram which shows the structure of the conventional system which pyrolyzes polymer waste.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Continuous polymer waste volume reduction system 2 Circulation system 3 Air interruption | blocking continuous injection | throwing-in apparatus 4 Air interruption | blocking continuous discharge | emission apparatus 10 Pyrolysis furnace 12 Capacitor 13 Oil collection pot 14 Separation tank 16 Circulation blower 17 Heat exchanger 21 Hot air furnace 22 Burner 23 Exhaust blower 24 Exhaust gas treatment device 25 Caustic soda injection device 26 Circulating water pump 30 Nitrogen gas generator

Claims (3)

A circulation system that performs thermal decomposition treatment with oxygen-free gas that circulates polymer waste, an air shut-off continuous input device that sends polymer waste to the circulation system in an oxygen-free state, and polymer waste after pyrolysis An air-blocking continuous discharge device that discharges substances out of the circulation system in an oxygen-free state, and an exhaust gas treatment device that purifies and discharges excess gas in the circulation system,
The circulation system includes a pyrolysis furnace for thermally decomposing the polymer waste sent by the air shut-off continuous input device with oxygen-free gas, and heat generated during pyrolysis of the polymer waste in the pyrolysis furnace. A condenser that cools the cracked gas and recovers oil; a heat exchanger that heats the pyrolyzed gas after the oil is recovered by the condenser as an oxygen-free gas; and the oxygen-free gas at least in the pyrolysis furnace A continuous polymer waste volume reduction system comprising: a circulation channel that circulates in the system through a condenser and a heat exchanger.   The continuous polymer waste volume reducing system according to claim 1, wherein surplus gas in the circulation system is used as a heat source of the heat exchanger. The apparatus further comprises an introduction gas generation device for generating nitrogen or water vapor to be introduced into the circulation flow path so as to make the inside of the circulation system oxygen-free when the operation is started and / or stopped. The continuous polymer waste volume reduction system described in 1.

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