I came across an interesting white paper from Sony on recycling styrofoam.
Additionally, and this is an important point, the evaporated limonene is returned to a clean liquid state and can be reused any number of times. This system can be said
to be a thoroughgoing recycling system which generates no waste.
Not only is the process use fully recyclable (and natural (linoene being extracted from the peels of oranges)) raw materials, it also does not degrade the chemical qualities of the original substance:
Since thermal processing is known to degrade the properties of some materials, one might wonder if this heating is safe. However, oxidation and breakdown of the polystyrene is suppressed since limonene oxidizes before polystyrene.
In addition, from a carbon output perspective:
Overall, the limonene method has CO2 emissions of about 0.6 kg of CO2 per 1 kg of styrofoam recovered. This is the smallest of all the methods, and about 1/3 the emissions associated with new polystyrene synthesis.
I hope we see this process becoming more widespread in the future.