AM Drilldown: New Report Suggests Advanced Plastics Recycling Could Cut Emissions Drastically

One of the most widely-touted advantages of additive manufacturing (AM) is the technology’s long-term potential to reduce carbon emissions. Yet, despite all the life-cycle assessments (LCAs) and other research into possible uses of AM as a tool for decreasing global industry’s overall carbon footprint, there remains at least one major unknown variable — which, eventually, could make all prior estimates of AM’s inherent sustainability seem far too conservative: the impact of advanced recycling methods.

That is borne out by a just-released report from the Earth Engineering Center (EEC) at the City College of New York (CCNY), “Quantitative Comparison of LCAs on the Current State of Advanced Recycling Technologies”, written by Dr. Marco J. Castaldi, chemical engineering professor and director of the EEC, and EEC research associate Lauren Creadore. Commissioned by the American Chemistry Council, the report analyzes 13 different LCAs concerning methods for advanced plastic recycling, none of which were released earlier than 2020.

In fact, one of its most noteworthy details involves the sheer increase, over the last 5 years, of the amount of studies done on plastic recycling: according to the report, “Nearly two times more studies examining plastics in a circular economy were released in 2019 compared to 2010-2017.” As the report illustrates, one way to help build circular economies revolving around plastic waste would be to boost infrastructure for advanced recycling: “All 13 LCAs reviewed consistently showed that advanced recycling yielded favorable circularity results.”

The report’s authors define “advanced recycling” as processes that “break down the plastic polymers to their chemical constituents to enable downstream processes to re-manufacture new plastic products or plastic-derived chemicals”. They divide all the various methods covered by the LCAs analyzed into two groups: thermal conversion and chemical depolymerization. According to the authors’ comparison of the various LCAs, thermal conversion methods, such as pyrolysis, are generally used for mixed plastics, while chemical depolymerization, including hydrolysis, are generally used for PET and colored polyesters.

Although the authors emphasize that no “single value” is sufficient “to represent the environmental impacts of advanced recycling technologies”, they nonetheless also reached conclusions with some impressive numbers attached to them. For one thing, using advanced recycling technologies can “reduce the need for fossil energy resources by up to 97%”. For another, adoption of advanced recycling technologies could lead to over 100 percent carbon reduction: as the authors explain, “such a reduction can be achieved due to credits earned from avoided products and/or energy”. In other words, the emissions reductions achieved from not creating new plastic products has to be taken into account.

AM is directly relevant to the implications of this study for that exact same reason. While AM is not necessarily a requirement for the establishment circular economies, it carries the potential to be a great asset towards their construction, and it would seem backwards in the sector, nowadays, for an OEM not to include the potential for circular economies on its list of selling points.

Thus, due to that fact, alone, the future opportunities for combining AM with advanced recycling seem virtually limitless. Regarding shorter-term potential, the recycling report should be especially exciting for any AM application involving pellet-extrusion, which is probably the market segment most immediately ready to be combined with advanced recycling methods.

Finally, given all of that, the significance of industrial “clusters” comes into clearer focus. Here, specifically, the need to coordinate the advanced recycling and advanced manufacturing supply chains seems obvious, and the National Strategy on Advanced Manufacturing and Bipartisan Infrastructure Law already appear to be setting that reality in motion. Most of all, however, as has always been the case, much of the will to recycle is going to have to come from consumer demand.

The AM sector, then, has yet another point favoring its compatibility with advanced recycling circular economies: the fact that the potential base of recycled plastic consumers it represents is largely comprised of small-to-medium manufacturers who are already concerned with controlling production costs. Compared to the conventional manufacturing sector, that is a much easier group to unify in the direction of a recycling-based supply chain.

Image of the Great Pacific Garbage Patch courtesy of University of Colorado.