JPS6063285A - Disposal unit for plastic waste - Google Patents

Abstract

PURPOSE:The plastic waste which is melted with heat in the pyrolysis furnace is increased in its surface area contacting with the gas phase to promote its gasification whereby high-efficiency pyrolysis of the waste is realized in a short time to recover the condensed oil. CONSTITUTION:Plastic waste is fed into the pyrolysis furnace 1 and the furnace is heated. The kettle containing the melt 3 is equipped with a stirrer composed of a rotary shaft 21 installed through the bottom of the kettle and spiral blades 22 and melted plastic waste is allowed to fall from the upper end of the blades 22, as the shaft is rotating. The melted waste is lifted up higher than its surface to increase its surface area contacting with the gas phase and promote its gasification. The resultant gas is cooled to collect condensed oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic waste processing apparatus that condenses and liquefies oil and recovers it by cooling the resulting gas.

In recent years, from the perspective of proper waste treatment and resource recycling, research and development has been conducted on systems that thermally decompose plastic waste and recover it as oil.According to currently known systems, plastic waste is The oil is thermally decomposed in a decomposition furnace, and the thermal decomposition residue generated in the furnace is cooled to condense and liquefy the oil and removed, and the remaining gas is combusted to recover its heat.

By the way, methods for pyrolyzing plastic waste in such a system include a method of burning the plastic waste in a pyrolysis furnace and a method of heating the pyrolysis furnace from the outside. However, when burning waste, there are problems in that the yield of pyrolysis gas decreases and high heat calories are generated, resulting in large wear and tear on the furnace.On the other hand, when heating the pyrolysis furnace from the outside, There is a danger that the flammable gas generated in the furnace could explode.

Therefore, we decided to heat the plastic waste by introducing it into the pyrolysis furnace with the air shut off.As a way to shut off the air, the plastic waste crushed into granules or powder was heated using an inert gas (e.g. nitrogen). It has been considered to pass it through a filled channel before feeding it into a pyrolysis furnace.

In such a pyrolysis furnace, plastic waste is heated and melted and evaporated from its surface.

However, the surface area for this purpose is limited to the internal cross-sectional area of the plastic storage pot of the pyrolysis furnace, so the larger the amount of plastic waste, the longer it will take to evaporate and vaporize, and the fuel cost required for heating and melting. The problem was that there were too many.

The present invention has been made in view of the above circumstances, and its purpose is to promote the vaporization of plastic waste heated and melted in a pyrolysis furnace as described above.

Hereinafter, specific examples of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows the overall configuration of a plastic waste processing apparatus. This processing device supplies plastic waste P that has been crushed into granules or powder into a pyrolysis furnace 1 using an appropriate feeding device, where it is thermally decomposed to generate pyrolysis gas, and this waste is The oil condensed from the waste is sent to a cooling tank 3 through a conduit 2, and the oil is stored in an oil storage tank 5 through a conduit 4. The oil is taken out from the lower part of the oil storage tank 5 through a conduit 6 and a switching valve 7. - The gas filling the L section is sent to a neutralization tank 9 through a conduit 8 to be neutralized, and then used for heating the pyrolysis furnace 1 through a conduit 10 and a conduit 11 branched from it. In addition, in the downstream part of the conduit 10 where the conduit 11 branches,
A switching valve 12 is provided for releasing gas into the atmosphere when the gas pressure within the processing apparatus rises above a limit.

In the above processing apparatus, the pyrolysis furnace 1 is equipped with a storage pot 13 for storing plastic waste, a heating burner 14 provided on the outside of the storage pot 13, and a branch conduit 11.
It is equipped with a nozzle 15 for burning the gas sent from. Therefore, when pyrolyzing plastic waste, first open the switching valve 17 provided in the fuel supply path 16 to the heating burner 14 and supply fuel to heat the storage pot 13. As the oil is thermally decomposed, the amount of residue filling the upper part of the oil storage tank 5 increases, and when it becomes possible to heat the oil sufficiently by burning the gas through the nozzle 15, the switching valve 17 is closed and the operation of the burner 14 is stopped.

According to the present invention, the storage pot 13 of the pyrolysis furnace l as described above
The following measures to promote the vaporization of plastic waste will be published:

First, FIG. 2 shows a spiral rotor blade 22 attached to a rotary ring 21 that rotatably passes through the bottom of the storage pot 13. As shown in FIG. The shaft 21 of this rotor blade is rotated at a predetermined speed by an appropriate rotary drive device 23 provided externally. A known mechanical seal 24 is provided on the bottom wall of the storage pot 13 through which the rotating shaft 21 passes.

The rotation R22 as the vaporization promoting means is controlled by the rotation drive device 23 so as not to rotate until the plastic waste stored in the storage pot 13 is melted and liquefied by heating. When plastic waste is melted and liquefied, a spiral blade 22 rotates at a predetermined speed.
raises it and drops it from the upper end of the rotor blade 22.

In this way, by pulling the molten and liquefied plastic waste above its surface, the contact area with the gas phase increases and vaporization is promoted.

Next, FIG. 3 shows a means for increasing the contact area between plastic waste and the gas phase in the same way as in FIG. do not have. That is, connect the conduit 31 to the bottom of the storage pot 13,
An inert gas such as nitrogen is introduced into the container 13 from a predetermined gas source through a conduit.

In this way, the inert gas introduced into the storage container rises in the form of bubbles within the molten and liquefied plastic waste and escapes from its surface. This increases the contact area between the plastic waste and the gas phase, promoting vaporization. Also, by filling the storage pot with inert gas, there is an effect that the risk of explosion due to pyrolysis gas is avoided.

As described above, according to the present invention, by increasing the contact area between the plastic waste heated and melted in the pyrolysis furnace and the gas phase, the vaporization of the plastic waste can be promoted. The time required for vaporization can be shortened and the fuel cost required for heating can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing the overall configuration of the plastic waste processing apparatus, FIG. 2 is an explanatory diagram of means for promoting vaporization of plastic waste, and FIG. 3 is a diagram showing another example of the means for promoting vaporization of plastic waste. l-111 pyrolysis furnace, 3-111 cooling tank, 5-111 oil storage tank, 9-111 neutralization tank, 13--1 storage pot,
14---1 heating burner, 21---1 rotating shaft, 2
2---One rotation mass, 23---One rotation drive device, 24-
--- Mechanical seal, 31 --- Conduit.

Claims (1)

[Claims] 1. Supplying plastic waste into a pyrolysis furnace, heating the pyrolysis furnace to pyrolyze the plastic waste to generate gas, and cooling this gas. In a plastic waste processing apparatus for separating and recovering condensed and liquefied oil, means for promoting vaporization of the plastic waste by increasing the contact area between the plastic waste heated and melted in the pyrolysis furnace and the gas phase. A processing device characterized in that it is attached to a pyrolysis furnace. 2.'' - Claims characterized in that the air distribution promoting means consists of a rotary blade that rotates within the pyrolysis furnace to cause the plastic waste to rise above its surface and then fall. The processing device according to item 1. 3. The vaporization accelerator means comprises a gas source that supplies an inert gas such as nitrogen, and a conduit that introduces the inert sludge from the sludge source into the molten plastic waste in the pyrolysis furnace. A processing device according to claim 1, characterized in that: