Touted as a solution, pyrolysis – technology that heats up plastic waste in the absence of oxygen – produces a type of oil that industries argue can be transformed back into ‘virgin-like’ plastic.
However, this latest report published by the environmental network Zero Waste Europe underlines the limitations of pyrolysis oil. Incompatibility with different plastic types, low yield, and contamination of pyrolysis oil means it must be diluted by a petroleum-based mixture, in some cases by a ratio of over 40:1.
The report, “Leaky loop “recycling”: A technical correction on the quality of pyrolysis oil made from plastic waste” argues that for pyrolysis oil to be used in the production of recycled plastic, it should either apply multiple energy-intensive purification steps or highly dilute the oil with virgin petroleum naphtha. Both options are not in line with the ambitions of the EU Green Deal.
Discussions underway to define a harmonised European approach to end-of-waste criteria for plastic will continue until 2025, when the review is foreseen to be adopted. Such a definition is crucial for pyrolysis as industry interests are to classify pyrolysis oil as a product. Decision-makers should not overlook the toxic compounds and purification requirements needed for pyrolysis oil and lower safety standards for the sake of developing a circular economy.
Lauriane Veillard, Chemical Recycling and Plastic-to-Fuels Policy Officer, states: “If pyrolysis oil is reclassified as a product instead of being classified as waste, as industry demands, it must meet EU requirements. We cannot afford to accept haphazardous legislation that undermines a true circular economy. Our north star should be the protection of the environment, human health and the public trust. These values should form the basis of different discussions on plastic recycling-related issues, like calculating recycled content and defining end-of-waste criteria.”
Low oil yield presents a significant problem with pyrolysis technology. Even in a best-case scenario, only 2% of the plastic waste fed into pyrolysis will actually make it into the “recycled” product, the report found.
The author of the report, Dr. Andrew Rollinson, states: “Physical laws dictate that the nature of pyrolysis is to synthesise new molecules, not just decompose plastic polymers. Since these laws are unlikely to yield in response to policy goals or alter as a consequence of marketing pressure, decision-makers would be sensible to accept the fact that pyrolysis will not somehow miraculously step up to the task required. Encouragement alone will not be enough to make pyrolysis solve the problem of plastic waste created by linear thinking in plastic production.”
