JPS6336924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for heating waste plastic to reduce its volume.

(Background technology) Waste plastics are a mixture of thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, and polyethylene, and thermosetting resins such as phenolic resins and urea resins. In addition, it often contains soil, paper,
It also includes other waste materials such as wood and food scraps.

Conventionally, as a means for reducing the volume of the above-mentioned various types of waste plastics and waste plastics in a broader sense including other wastes, this kind of waste plastics is suspended in a hot air retention chamber, and a discharge port is provided at the bottom. It is heated by indirect heating from the outside of the melting chamber and direct heating by hot air introduced from a hot air introduction pipe provided in the melting chamber to melt it. In this case, the waste plastics are stored and held in the hot air oven by a holding rod installed near the discharge port or other means, and the melted waste plastics are removed by a scraping means or the hot air oven. The vibrating means prevents the waste from adhering to the furnace wall, and the waste is scraped toward the outlet or forced down.

(Technical Problem) An object of the present invention is to store and retain waste plastic inside a hot blast stove even if scraping means, vibrating means, holding rods, etc., which complicate the structure of the device and increase manufacturing costs, are eliminated. It is an object of the present invention to provide a method and apparatus for volume reduction processing of waste plastics, which can be used to store waste plastics and smoothly drop the softened and melted waste plastics to a discharge port.

(Technical Means) In order to achieve the above-mentioned technical problem, the present invention provides a method for reducing the volume of waste plastic in a hot blast furnace having a discharge opening at the bottom thereof. Using a funnel-shaped thing with no obstructions on the inside of the coaxial direction, cover the discharge port with a container, and introduce hot air into the hot air stove from the hot air introduction pipe provided on the peripheral wall of the hot air stove. The waste plastic is heated while being kept suspended so that it does not stick to the furnace wall or fall from the discharge port due to the hot air.

The present invention also performs volume reduction treatment by keeping the heating temperature within the range of 300°C.

The invention further includes a hot-air chamber and a hot-air stove provided in the hot-air chamber, and the hot-air stove has a head portion consisting of a large diameter portion and a neck portion consisting of a small diameter portion provided with a discharge port at the tip in the same axial direction. The head and neck are provided with a plurality of hot air introduction pipes extending upward and downward in the circumferential direction for introducing the hot air in the hot air retention chamber into the inside of the head and neck. A container for accommodating the softened molten material is provided at the discharge port so as to be movable up and down.

The present invention is further configured such that the tip of the hot air introduction pipe is flush with the inner surface of the hot air stove.

(Function) With the above-described configuration, the waste plastics put into the hot blast furnace are heated while being suspended, without falling down immediately, even without providing a holding rod or other means at the discharge port. Therefore, even if it softens and melts, it will not stick to the furnace wall, and as the specific gravity increases due to softening and melting, it will gradually escape from the floating state and fall to the discharge port side, so it will not clog. This allows for smooth discharge from the discharge port side without causing any problems.

(Embodiment) An embodiment of the present invention will be described below in detail based on the drawings. Reference numeral 1 denotes a blower for taking in outside air, which is connected to a hot air generating furnace 3 equipped with an oil burner 2 through an intake pipe 4. connected. A known deodorizing tank 5 is provided in the upper part of the hot air generating furnace 3.
This deodorizing tank 5 includes an exhaust blower 6 and a circulation pump 7.
is attached. A hot air retention chamber 8 constructed of heat insulating walls 8a and 8b is provided on the left side of the blower 1 for taking in outside air, and an outlet 3a of the hot air generating furnace 3 is opened on one side of the heat insulating wall 8a. Inside the hot air retention chamber 8, there is a funnel-shaped hot blast furnace 9 in which a head portion 9a consisting of a large diameter portion and a neck portion 9b consisting of a small diameter portion having a diameter approximately one-third of the large diameter portion are coaxially connected.
is provided, and a discharge port 10b is opened at the end of the neck portion 9b. An input chamber 1 is provided in the upper part of the hot air retention chamber 8 so as to cover the opening upper part 10a of the hot air stove 9.
1 is provided, and a charging lid 12 is attached to this charging chamber 11. A plurality of hot air introduction pipes 1 are installed in the head 9a and neck 9b of the hot air stove 9 in the upper and lower circumferential directions.
3, 13, 13, . A discharge chamber 14 is provided around the discharge port 10b of the hot air stove 9, and the discharge chamber 14 includes a discharge port 10b.
The container 15 is placed on, for example, a movable hydraulic jack 20 so as to face and close the container 15, and a discharge lid 16 is attached to one side of the container 15. The exhaust pipe 17 has one end connected to the deodorizing tank 5, and the other end connected to the discharge chamber 14 and the input chamber 11, respectively.

Now, ignite burner 2 and turn on blower 1.
After confirming that the inside of the hot-blast stove 9 has reached about 200°C, the charging lid 12 is opened and a mixture of miscellaneous waste plastics such as maltprene, styrofoam, and polyethylene head is charged, and the spear charging lid 12 is closed.

Then, at this time, the hot air has already passed through the hot air retention chamber 8 from the hot air generating furnace 3, and the hot air introduction pipes 13, 13, 13...
The hot air that is being sent into the hot air stove 9 spirals and descends along the inner wall of the hot air stove 9, and the hot air is sent into the hot air stove 9.
from the discharge port 10b, but the discharge port 10b
Since it is blocked by the container 15, it reverses and becomes an even stronger updraft and is blown upwards in the hot blast furnace 9. This wind force causes the unsoftened and melted material charged from the charging chamber 11 to The first piece of waste plastic is kept floating without falling directly to the discharge port 10b. However,
Heavy objects such as stones and metals fall into the container 15 despite the strong updraft.

As the amount of waste plastic input increases,
Since the waste plastics are condensed at the neck portion where the diameter has become smaller, this pressure prevents them from falling toward the discharge port side, while at the same time, the waste plastics are also introduced from the hot air introduction pipes 13, 13, 13... The hot air swirls and creates a gap 18 between the inner wall of the hot air stove 9 and the outer periphery of the thrown-in lump of waste plastic, as shown in Fig. 2. The plastic 19 is rotated and heated in a floating state in the hot air stove 9 by the upward current of the introduced hot air and the rotating air current.

This heating includes indirect heating by hot air in the hot air retention chamber 8 via the hot air stove 9, and direct heating by hot air introduced into the hot air stove 9 via the hot air introduction pipes 13, 13, 13... This is two-stage heating.

By the way, as mentioned above, many different types of plastics are mixed in municipal garbage and industrial waste, and the mixing ratios vary. Therefore, the heating temperature inside the hot air stove 9 is also around 150℃.
There is a wide selection range up to about 400°C, but in general, if the temperature exceeds 400°C, the plastic will begin to burn and the amount of toxic gas generated will increase, which is undesirable, so the temperature should be kept below 400°C.

However, if the heating temperature exceeds 300°C, depending on the type of plastic, dioxin may be generated, so the most preferable heating temperature is in the range of 150°C to 200°C. In this temperature range, the waste plastic softens without melting, and as the specific gravity increases, it falls toward the discharge port 10b against the rising air current. The reason why indirect heating and direct heating are used together to heat the hot air stove 9 is that the former provides sufficient heat to the entire hot air stove 9, and the latter uses direct heating to adjust the heating state inside the hot air stove 9. The hot air blown downward spirally from the hot air introduction pipes 13, 13, 13, etc. attached to the circumferential wall of the hot air stove 9 upward and downward in the circumferential direction is used to absorb the softened and melted waste plastics on the inner wall of the hot air stove 9. While preventing adhesion, the hot air stove 9
The input waste plastic is softened, melted, condensed, and moved to the lower center of the hot blast furnace 9.

Finally, despite the increase in specific gravity and strong upward airflow, the air passes through the neck 9b and reaches the discharge port 10.
From b, the liquid drips or falls into the container 15 in sequence.

At this time, thermosetting resins that do not soften, stones, garbage, etc., are left in the container 15 as they are, or together with the softened and molten plastics, because there is no obstruction such as a holding rod at the discharge port unlike in conventional products. It falls smoothly without getting caught.

On the other hand, wood, paper, etc. are burned, and ash and other solid materials fall into the discharge port 10b together with softened and molten plastic, but the combustion gas goes into the input chamber 11 along with other generated gases, and is connected to the upper part of the chamber 11. The odor is guided to the deodorizing tank 5 via the exhaust pipe 17, deodorized, and then discharged to the outside by the exhaust blower 6.

When the softened and molten waste plastics have accumulated in the container 15, the discharge lid 16 is opened, the container 15 is lowered, and the waste plastics are taken out to the outside and solidified and molded. Note that the discharge port 10b of this container 15
The sealing does not necessarily have to be complete, and even if there is a slight gap, no problem will occur as long as the amount of air that keeps the waste plastic suspended in the hot air stove 9 is ensured.

The product solidified and molded as described above has a shape in which the melted and softened plastic is used as a binder, and other non-softened plastics and waste are solidified into a compact shape. For example, garbage mainly made of foamed plastic can be reduced to several tenths of its original volume, and can be recycled (secondary treatment) or landfilled. It is also extremely easy to handle.

(Effects) As explained in detail above, this invention is a device that has a simple structure, reduces the risk of failure, and can significantly reduce costs. It is possible to achieve the effect that the volume reduction process can be carried out extremely smoothly and continuously without causing any problems.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view schematically showing the present invention, and FIG. 2 is a sectional view of essential parts for explaining the invention. 3...Hot air generation furnace, 8...Hot air retention chamber, 9...
Hot air stove, 13... Hot air introduction pipe, 14... Discharge chamber,
15... Container.

Claims (1)

[Scope of Claims] 1. When waste plastic is subjected to volume reduction treatment in a hot blast furnace with a discharge port opened at the bottom, an obstacle is placed inside the hot blast furnace where the discharge port is provided coaxially. Using a hollow funnel-shaped object, the discharge port is covered with a container, and waste plastic is introduced into the hot air furnace while introducing hot air from a hot air introduction pipe provided on the peripheral wall of the hot air furnace. A method for reducing the volume of waste plastics, characterized by heating the waste plastics while keeping them suspended in hot air so that they do not stick to the furnace wall or fall from the discharge port. 2. The method for volume reduction of waste plastics according to claim 1, characterized in that the heating temperature is in the range of 300°C. 3. It includes a hot-air chamber and a hot-air stove installed in the hot-air chamber, and this hot-air stove has a head consisting of a large diameter part,
The neck part consisting of a small diameter part with a discharge port provided at the lower end is provided coaxially and is shaped like a funnel with no obstruction on the inside, and the head and neck part are used to direct hot air from the hot air retention chamber A method for reducing the volume of waste plastic, characterized in that a plurality of hot air introduction pipes are installed circumferentially upwardly and downwardly, and a container for storing the softened molten material is installed at the discharge port so as to be movable up and down. Processing equipment. 4. The waste plastic volume reduction processing apparatus according to claim 2, characterized in that the tip of the hot air introduction pipe is configured to be flush with the inner surface of the hot air stove.