Chemical Processing of Plastic Packaging Waste

About 300 million metric tons (mt) of plastic waste are believed to have been generated globally in 2018.  And about 45 to 50% (135 to 150 million mt) of this 300 million mt of plastic waste are estimated to be plastic packaging waste.    Unfortunately, a large amount of this 135 to 150 million mt of plastic packaging waste was not recovered (recycled) (for example only about 15% in the United States and about 40% in Europe).  One of the restraints on the recycling (recovery) is that only some of the plastic package waste (that portion having the needed properties such as uniformity), can be recycled using mechanical processes.   Much of the rest of the plastic packaging waste does not have the needed uniformity and other properties to be mechanically process and recycled.   

In order to recycle the rest (the amount not able to be mechanically recycled), the plastic needs to be chemically recycled.  In generally, when the term chemical recycle is used, it refers to one of these three methods:

1.      Purification – dissolving the plastic into solution followed by purification into components, which then can be used to form new plastics;

2.      Decomposition – de-polymerization of the plastic by various means into the monomers, which then can be used to form new plastics; and

3.      Conversion – using pyrolysis to convert the plastic packing waste into oils or gasification to convert plastic wastes into hydrogen, carbon monoxide, and carbon dioxide (syngas), which then can be used to form new plastics.

Unlike in mechanical recycling, which eventually will mechanically damage the plastic after repeated recycling, chemical recycling of the newly formed plastics can continue indefinitely.

The Center for the Circular Economy at Closed Loop Partners has produced a 2018 report that provides an excellent review of chemical recycling and identifies dozens of companies that have developed various purification, decomposition, and/or conversion processes for recycling plastic packaging waste.  Click here to read the report (PDF file).

Estimates can be found on the Internet that the plastic packaging waste that is not recycled could be converted into new plastic (from the components, monomers, or syngas produced via the chemical recycling process) with a market value of $80 to $120 billion.   Also, reusing plastic packaging waste as new plastic products avoids using fossil fuels to make the needed products, reducing carbon dioxide emissions.  And, recycling the packaging prevents the entry of the plastic into the environment as waste.  So, for these reasons, as well as for the technical advances that are being made in chemical recycling, as indicated in the Center for the Circular Economy Report, much interest is being generated in chemical recycling of plastic wastes.