Design and Evaluation of a Sink Float Separation Tank for Recycling, Using Waste Plastics in Kasugai City

抄録

Plastics recycling can be classified into mechanical and chemical recycling. In this study, assumptions were made based on the 3 models for the recycling of waste plastics, and the CO₂ emissions were calculated. In these models, the 4 tonnes of bailed waste plastics collected from Kasugai homes was transported from Kasugai city to Toyama city (mechanical recycling) and Tokai city (cokes oven pre-treatment process). In the case of incineration, the waste plastics were incinerated directly in Kasugai city. From the calculation results, the value of the CO₂ emissions for incineration was more than the two other processes; however the value of CO₂ emission for cokes oven pre-treatment process was low compared to the mechanical recycling. This is because of short transportation distance after bailing, and a simple sorting and pelletizing system. Therefore, in mechanical recycling, the bailed plastics should be taken to a much closer location for example Gifu city and the crusher and sink float separation tank should be simplified. A new tank for sink float separation of wastes plastics was designed, the flow of water in the tank was observed and an experiment was conducted with waste plastics; thereafter the recovery rate and the energy reduction consumption was taken into account. It is therefore concluded that there was a reduction in CO₂ emission for the new sink float tank for mechanical recycling.