A recent report released by the environmental network Zero Waste Europe (ZWE) questions the efficacy of pyrolysis, a technology hailed by some as a “miracle” solution. Pyrolysis is the process of heating plastic waste in the absence of oxygen and has been championed for its potential to transform plastic waste into a pristine state.

However, the report, titled ‘Challenges and Limitations of Pyrolysis: A Critical Examination of the Quality of Pyrolysis Oil from Plastic Waste,’ sheds light on the shortcomings of this technology and challenges industry claims.

The report raises concerns about pyrolysis oil. One major issue is the technology’s inability to work with various plastic types, severely limiting its practical application.

Additionally, the report highlights the low yield of pyrolysis oil and the necessity for rigorous contamination control. This often involves diluting the pyrolysis oil with petroleum-based mixtures, sometimes at ratios exceeding 40:1 to make it usable.

These findings cast doubt on the environmental viability of pyrolysis technology, particularly in the context of the European Union’s Green Deal. The report calls on decision-makers not to compromise safety standards and to consider the toxic compounds and purification requirements associated with pyrolysis oil when pursuing a circular economy.

Lauriane Veillard, a chemical recycling and plastic-to-fuels policy officer at Zero Waste Europe, emphasized the importance of adhering to EU regulations related to packaging waste recycling. These regulations aim to ensure that only recyclable packaging is on the market by 2030, taking into account the capabilities of various technologies and addressing challenges related to materials like inks.

Veillard also questions the sustainability of pyrolysis technology, citing its substantial energy demands, which are closely tied to the energy grids of EU member states. She notes that if the energy source becomes scarce or environmentally unsustainable, the long-term viability of the technology is at risk.

Furthermore, Veillard points out a significant issue with pyrolysis – a considerable loss of plastic materials, where roughly 53% of the carbon content is either lost during the process or converted into fuels. This leakage of materials raises concerns from a circular management perspective.

The report also addresses the release of dioxins, highly toxic compounds that are unintended by-products of specific manufacturing processes. In plastic waste pyrolysis, where plastic is heated without oxygen, conditions conducive to the formation of dioxin precursors are created. These substances are both environmentally problematic and pose health risks as they are recognized as carcinogenic.

Veillard contends that the claim of achieving a “virgin-like quality” for recycled content through pyrolysis is highly debatable.

The ZWE report underscores the challenges and limitations of pyrolysis, including its low oil yield. Even under the best circumstances, only 2% of the plastic waste subjected to pyrolysis is recovered as a “recycled” product. Dr. Andrew Rollinson, the report’s author, explains that pyrolysis is designed to synthesize new molecules, not just break down plastic polymers, making it insufficient to address the plastic waste issue caused by linear thinking in plastic production.

The report’s findings prompt a critical reevaluation of the claims made by the pyrolysis industry and its role in the transition to a circular economy. It emphasizes the need for energy-intensive purification or extensive dilution of pyrolysis oil to remove contaminants that are inherently present, which are often tied to plastic additives like iron, arsenic, or aluminum. The pyrolysis process itself generates new, unwanted, and toxic hydrocarbons, further complicating its suitability as a sustainable solution.