JPH0211307A - Treating of foamed polystyrene waste - Google Patents

Abstract

PURPOSE:To improve the quality of a product being reused by treating foamed polystyrene waste pieces with a low pressure steam and performing defoaming and reducing. CONSTITUTION:Electric heating wires 2 are set on the upper part of a hopper for a foamed polystyrene waste 1. The foamed article is cut into small pieces of, e.g. 5-10cm by means of these electric heating wires. The cut foamed small pieces are dropped in a reducing tank 3 consisting of an iron container. A low pressure steam having a temp. of 120-160 deg.C and a pressure of 3-6kg/cm<2> is introduced into the reducing tank 3 from port 4 and exhausted from 5. The defoamed and reduced products therein are dropped in an attritor 6, wherein they are ground into granules of e.g. 10-30mm, which are dropped from the port 7. In addition, partition plates 8 and 9 are set on the upper and lower parts of the reducing tank 3 and they are intermittently opened.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for treating expanded polystyrene.

(Conventional technology) In recent years, due to the rationality (convenience) of plastics, the amount of plastic used has been increasing steadily, and it has entered not only the industrial field but also every field of ordinary households. Therefore, measures to deal with waste have become a social issue, and conventional methods such as landfilling and incineration are not only insufficient, but also hinder land use and cause secondary pollution due to exhaust gas, etc. is also occurring.

Therefore, various studies are being conducted on the reuse of plastic waste, but there are many problems in terms of economy, safety, quality of recycled products, etc., and in reality, only a small portion is reused. .

In particular, expanded polystyrene products are used in large quantities as various food containers because they are inexpensive and have excellent heat retention properties, and the disposal of their waste has become a major social problem.

Expanded polystyrene products usually have a high expansion ratio of about 40 to 70 times, so attempts have been made to defoamer and reduce the size using hot air, etc., but this is not safe, has low efficiency, and requires equipment. However, there were problems in that the quality and efficiency of reuse of reused products were poor because they were expensive, and the reduced products tended to turn black.

(The purpose of the present invention is to solve the above-mentioned problems, and in particular, to make foamed polystyrene waste highly safe, inexpensive, and easy to reuse, and to make recycled products. It is an object of the present invention to provide a method for processing expanded polystyrene waste that is excellent in quality.

(Means for Solving the Problems) The present invention resides in a method for treating foamed polystyrene waste, which comprises treating foamed polystyrene waste pieces with low-pressure steam to defoam and reduce the size of the foamed polystyrene waste pieces.

The foamed polystyrene waste used in the present invention is not particularly limited, and those used as containers for foods such as fish and meat can be used as appropriate, but those with a high expansion ratio of 30 times or more are particularly preferred. It will be done.

Expanded polystyrene waste is usually separated into 5 types to make it easier to dispose of.
It is cut into pieces approximately 50 cm in size and filled into airtight containers. Low pressure steam is then introduced into the vessel. This low-pressure steam has a temperature above 100°C, which is sufficient to cause defoaming, but below a temperature that would cause the polystyrene pieces to fuse together. Here, the term "not fused to each other" includes a state in which even though they are apparently attached, they separate with a slight impact such as being hit. In other words, if a blow is applied to the defoamed and reduced product, and the polystyrene pieces remain attached to each other, but mainly other parts are destroyed, the polystyrene pieces have fused together. The temperature of such water vapor is usually 120 to 160°C, preferably 13°C.
The temperature is 0 to 150°C and the pressure is about 3 to 6 kg/cJ, preferably about 3.5 to 4.5 kg/cd, and the optimum conditions are determined depending on the equipment, the size of the foam, etc. Examples of steam with certain conditions include waste steam from general factories, and therefore the cost of steam can be kept low. In addition, since the filtration method uses low-pressure steam, it is safe, there are no operational problems even if moisture adheres to the surface of the treated object, and preliminary treatment is easy, and it is also easy to use due to the material and design of the reduction tank. No special consideration required.

Although the volume of the reduced piece obtained by the above treatment is reduced to about 1/10 to 1740 of the original volume, it still has a certain expansion ratio (for example, 15 times or more).

As a result, the polystyrene itself does not melt and maintains substantially the same molecular state as the foam.

The reduced pieces thus obtained have the advantage of being easy to transport, as well as being substantially free of quality deterioration such as blackening, and are extremely easy to pulverize into granules.

Since this granulated material is essentially an incomplete foamed material and is not a molten solid, it is characterized by being extremely easy to carry out subsequent recycling processes such as transportation and melting. In addition, since it has only undergone a relatively mild steam treatment, there is no inhomogeneous matter mixed in due to carbonization during the treatment process, and the quality is stable. As a result, when this granular material is melted and the vapor generated by thermal decomposition is further thermally decomposed using a solid acid catalyst, it is possible to obtain an extremely high quality hydrocarbon oil consisting mainly of aromatic hydrocarbons at a high yield. Shows the characteristic of .

Here, an example of an apparatus effective for carrying out the present invention will be explained based on the drawings.

FIG. 1 is a sectional view showing an example of a filtration apparatus used for carrying out the method of the present invention.

An electric heater wire 2 for cutting foam is installed above the input port for foamed polystyrene waste 1. The foam is cut into pieces of, for example, about 5 to 10 cm using this electric heater wire. The cut foam pieces are placed in a reduction tank 3 consisting of an iron container.
to fall. Reduction t1! Low pressurized steam is introduced into I3 from 4 and discharged from 5.

The defoamed and reduced product thus reduced in size is dropped into a coarse crusher aI 6 and crushed into particles of, for example, about 10 to 30 particles, and the granules are dropped from 7. Furthermore, partitions 8 and 9 are provided at the upper and lower parts of the reduction tank 3 and can be opened and closed intermittently.

It is also preferable to provide two or three reduction tanks in parallel and perform the reduction work semi-continuously. Further, it is preferable to keep the entire reduction tank warm.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of an apparatus used for carrying out the present invention.

Claims (1)

[Claims] 1. A method for treating foamed polystyrene waste, which comprises treating foamed polystyrene waste pieces with low-pressure steam to defoam and reduce the size of the foamed polystyrene waste pieces. 2. The method according to claim 1, wherein the temperature of the steam is 120 to 160°C. 3. The method according to claim 1 or 2, wherein the pressure of the water vapor is 3 to 6 kg/cm^2. 4. The method according to claim 1, wherein the defoamed reduced product is pulverized. 5. The method according to claim 4, wherein the pulverized product is thermally decomposed and converted into hydrocarbon oil.