ENERGY INPUT AND PROCESS FLOW FOR PLASTIC RECYCLING

Millions of tons of plastic are produced worldwide every year. The plastic waste may go down several paths through its life, including being sent to a landfill (85.5% in the US), recovered for energy (7.7%), or recycled (6.5%). This paper discusses current and prospective recycling methods, comparing primary and secondary mechanical recycling, technologically developing chemical recycling (including Idaho National Laboratory’s ChemPren process), and energy recovery. Material and energy flows were created for nominal polyethylene terephthalate (PET),high density polyethylene (HDPE), andpolypropylene(PP) bottle recycling facilities in the United States. The energy and emission rates for these mechanically recycled plastics is significantly lower than with virgin pellet production, but has higher costs, including transportation and waste sorting. Energy recovery, although cheaper than landfills, produces the highest carbon dioxide emissions of all plastic end of life routes.