Major Japanese polystyrene (PS) manufacturer PS Japan Corp. is pursuing a demonstration project to test the chemical recycling of used PS. Coming as a joint effort with Toshiba Plant Systems & Services Corp. (TPSC), this project will see thermal energy applied to break down used PS back into its raw material, styrene monomer.
The project will employ TPSC’s proprietary chemical recycling technology, which besides boasting a high recovery rate also emits less CO2 than when manufacturing styrene monomer from crude oil. The pilot plant is scheduled for completion in March 2022, and will operate at a scale of between 1,000 and several thousand tons per year.
To carry out its recycling, the project will take in waste PS from applications such as food packaging and home appliance parts. The styrene monomer made from recycling this PS will be evaluated over a course of about a year.
Currently, the main recycling method for PS is mechanical recycling, in which used PS food packaging and the like gets converted back into PS. However, this method has certain issues; for example, there are difficulties in dealing with PS containers that are colored or soiled with food waste, and using the method for repeated recycling deteriorates the physical properties of the PS.
An alternative, then, is to establish an effective chemical recycling technology able to convert materials back into their original building blocks. This could expand the scope of resource recycling and help contribute to a circular economy.
PS can be converted back into its raw material via energy-efficient processes, making it suitable for chemical recycling. And beyond just PS Japan, a number of other Japanese companies have started developing technologies for this field.
Toyo Styrene Co. Ltd., for example, has begun building a demonstration facility with an annual operational scale of 3,000 tons per year, and aims to have this begin operations by the end of fiscal 2021. Meanwhile, DIC Corp. (TYO:4631) has partnered with a major food packaging company to start operations by 2022 at a demonstration facility with a scale of several thousand tons per year.