JP2000317935A - Method for granulating waste plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently heat and granule by drying a waste plastic, regulating its moisture content to a specific value or below, and then granulating the plastic by a die granulator. SOLUTION: The waste plastic 6 in which a film-like plastic is separated is comminuted in a suitable size by a comminutor 2, heater or dried by an air flow by a dryer 3, or wet gravity separated, then dehydrated, or a chlorine- containing plastic is separated by a centrifugal specified gravity separator and simultaneously dehydrated to regulate its moisture content to 20% or below. Then, the plastic is granulated by avoiding a closure in the die by a die type granulator 4 while eliminating melt insufficiency or an excess melting of the plastic. The film-like plastic separated from the plastic 6 is also similarly treated, and granulated by the granulator 4. Thus, closure of the granulator 4 can be avoided, no trouble of granulating fault occurs, and granules 5 of good quality can be continuously obtained. The film-like plastic can also be improved in its granulating efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to waste plastics (hereinafter referred to as "waste plastic") in which film plastics, lump plastics and the like are mixed, and is used for blowing raw materials such as blast furnaces and other solid fuels (hereinafter referred to as "solid waste plastics"). RD
F)) and re-use for oiling,
The present invention relates to a granulation method for processing into a shape suitable for pneumatic transportation and truck transportation.

[0002]

2. Description of the Related Art Waste plastics are reused for furnace blowing raw materials such as blast furnaces, other solid fuels (RDF), and oil conversion. For reuse, it is important to process into solids and granules suitable for pneumatic transportation such as blown into a blast furnace and truck transportation.

[0003] As the above-mentioned processing method, a method of crushing and pulverizing a bulk plastic in waste plastic is performed. Heat granulation is performed on film plastics. As a heating granulation means, a method is known in which a film-shaped plastic is heated to the melting point of the plastic by frictional heat or external heating while being stirred and melted, and then cooled with water or the like to the melting point or lower to granulate.

[0004] A method is also known in which a plastic is taken out of a hole in a die by using a die-type granulator by compressing and heating.

[0005]

In particular, when the above-mentioned die-type granulator is used, insufficient melting or excessive melting occurs depending on the type of waste plastic and the operating conditions.
There is a problem that many defective granulated products are generated. In particular, in the case of excessive melting, as shown in FIG. 2, there is a problem that the operation cannot be performed because a blockage occurs in the die.
FIG. 2 is a graph showing the relationship between the water content and the state of granulation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of granulating waste plastic which can efficiently carry out heating granulation of waste plastic by a die-type granulator without causing the above-mentioned problems. .

[0007]

According to the first aspect of the present invention,
In the step of granulating the waste plastic, a step of drying the waste plastic to adjust the water content to 20% or less; and
The method is characterized by including a step of processing the waste plastic having adjusted moisture content into granules using a die-type granulator.

According to a second aspect of the present invention, in the step of granulating the waste plastic, a step of separating the film-like waste plastic from the waste plastic, and drying the separated film-like waste plastic to adjust the water content to 20% or less. It is characterized by including a step and a step of processing the waste plastic film having adjusted moisture content into a granular form using a die-type granulator.

[0009] Waste plastic contains 15 to 40% of water, and if it is put into a die-type granulator as it is, it may cause poor granulation. Therefore, the water content of waste plastic is 20% or less. And then supply it to the die granulator.

As a method for adjusting the water content of the waste plastic, the following method (1), (2) or (3) may be used. (1) Pulverize waste plastic to an appropriate size in advance. Alternatively, the film plastic is separated from the waste plastic.

The above-mentioned pulverized waste plastic or separated film-like plastic is dried by a dryer of a heating type or a flash drying type to adjust the water content to 20% or less. (2) The above or is subjected to wet specific gravity separation, followed by dehydration treatment to adjust the water content to 20% or less. (3) The above or the above is applied to a centrifugal specific gravity separator to simultaneously separate the chlorine-containing plastic (PVC separation) and dehydrate the water, thereby adjusting the water content to 20% or less.

By adjusting the water content of the waste plastic or the film-like plastic to 20% or less, preferably 10% or less and then feeding the waste plastic or the die-type granulator, insufficient melting and excessive melting are eliminated, and blockage in the die is prevented. And granulation is carried out constantly.

In particular, by applying the present invention to a film-like plastic separated from waste plastic, even a film-like plastic in which the above-mentioned problem is likely to occur can be efficiently treated by a die-type granulator.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a process diagram illustrating and illustrating equipment used for performing a process of granulating waste plastic according to an embodiment of the present invention.

The waste plastic 6 is fed into the crusher 2 by the feeding conveyor 1. Waste plastic input 6
Is the desired size (5-200 mm) by the crusher 2.
Crushed. Next, the foreign matter (metal or the like) is removed using a magnetic separator (not shown) or the like. Next, the waste plastic is put into the dryer 3, and the water content of the waste plastic is adjusted to 20% or less. Next, it is put into the die-type granulator 4 and the granulated material 5
Is granulated. Since the water content of the waste plastic charged is 20% or less, in the die-type granulator 4, insufficient melting and excessive melting are eliminated, and no clogging in the die occurs, and the granulated material 5 is continuously and stably obtained.

Incidentally, by separating the film-like plastic from the waste plastic and thereafter performing the steps after the above-mentioned foreign matter removing step, the granulated material can be similarly granulated from the film-like plastic.

[0018]

As described above, according to the present invention, the following useful effects are provided.

By adjusting the water content of the waste plastic to 20% or less when the waste plastic is heated and granulated by the die-type granulator, clogging of the die-type granulator is avoided, and troubles of poor granulation occur. High quality granulated material can be continuously obtained, and granulated material having a shape suitable for blast furnace injection and transportation can be continuously and efficiently obtained from waste plastic. It can be reused for RDF and oiling applications.

In particular, since a die-type granulator can be applied even to a film-like plastic in which a trouble easily occurs, the granulation efficiency of the film-like plastic is improved.

[Brief description of the drawings]

FIG. 1 is a process diagram illustrating and illustrating equipment used for performing a granulating process of waste plastic according to an embodiment of the present invention.

FIG. 2 is a graph showing the relationship between the water content and the state of granulation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input conveyor 2 Crusher 3 Dryer 4 Die-type granulator 5 Granulated material 6 Waste plastic

Claims (2)

[Claims] 1. A step of drying waste plastic to adjust the water content to 20% or less in a waste plastic granulation step, and granulating the waste plastic having the adjusted water content using a die-type granulator. A method for granulating waste plastics, comprising a step of processing into waste plastics. 2. A process for separating waste plastic film from waste plastic in a process of granulating waste plastic, a process for drying the separated waste plastic film to adjust the water content to 20% or less, and a water content. A method for granulating waste plastics, comprising the step of processing the film-like waste plastic prepared as described above into granules using a die-type granulator.