November 02, 2022

Using thermal conversion technologies to recycle mixed plastics waste

NexantECA - Using Thermal Conversion Technologies to Recycle Mixed Plastics Waste

For many years, plastics have been recycled using conventional (i.e., mechanical) recycling methods. However, of the large amounts of plastic waste generated globally, only 9 percent of the plastic waste is recycled. Since increasing recycling rates is a priority as an approach to reducing plastic pollution, new focus is being placed on advanced recycling technologies that can complement mechanical recycling. Thermal conversion processes (mainly pyrolysis and hydrothermal treatment) can process mixed plastics, a key problem for other recycling methods. These advanced recycling processes continue to gain momentum due to their ability to process hard-to-recycle plastics (including mixed plastics waste) and produce hydrocarbon products suitable for use as petrochemical feedstocks. 



Except for bottle-to-bottle recycling of PET and HDPE, which involve mechanical recycling and super-clean technology, plastics that are mechanically recycled are generally downcycled, a major weakness of mechanical recycling. All advanced recycling processes result in products that can be used either in the same application (including food-grade) or upcycled. Thermal conversion technologies target mixed plastics waste (#3 to #7 plastics) and difficult-to-recycle plastics (e.g., film, including multi-layer flexible packaging), where the main recycling option has been to include them in MSW streams that are sent to waste-to-energy facilities, as an alternative to landfilling. 



Plastic producers are actively investing in technologies under the pressure of stricter government regulations (such as plastic bag bans) and end users’ increased preference for sustainable materials. At the same time, governments are implementing recycled content mandates and consumer brands are making pledges to increase recycled material content to address growing public awareness. Consumers favor environmentally friendly alternatives resulting in bold sustainability commitments. However, there is a disconnect between the amount and type of plastics recycled and that needed to meet the mandates and other commitments. Thermal conversion technologies are positioned for widespread commercialization and scale-up.  

As part of a recently published special report, NexantECA conducted a strategic analysis of thermal conversion processes and their viability for the production of olefins from mixed plastics waste. This detailed study includes: 

  • High level profiles of pyrolysis and hydrothermal treatment technology developers, including a ranking of these technologies 


  • Overview of post-treatment of thermal conversion products 
  • Economic analysis of generic pyrolysis and hydrothermal treatment technologies for the production of plastic-based naphtha and production of ethylene from these plastic-based products in 2Q 2022 for USGC, Western Europe, China, Japan, and Southeast Asia 

  • Carbon capture and sequestration analysis 
  • Delivered cost competitiveness to Western Europe 
  • Analysis of the carbon intensity of ethylene 
  • Regional maps depicting locations of existing and planned advanced recycling facilities 
  • Strategic and business considerations (e.g., SWOT, crude oil price environment effect on thermal conversion profitability, potential applications for thermal conversion technologies, etc.) 

To meet current government mandates and producer-stated goals, development and commercialization of thermal conversion processes should be continued. However, improvements in collection and sortation infrastructure are required in order to achieve this. For mixed plastics waste, thermal conversion processes are currently the only viable option that can handle a heterogeneous stream. These processes are complementary to mechanical recycling, and all processes will be required to increase recycling rates. Solving the plastic waste problem is challenging. Since plastics will continue to be ubiquitous materials, switching to a circular economy model will require the collaboration of governments, waste management companies, resin producers, converters, brand owners, retailers, and consumers. Regulations, technical know-how, resources, and innovation need to be entwined to successfully reduce plastic waste while maintaining the functionality of plastics. 


Find out more….. 

In its newly published Thermal Conversion Technologies – An Answer to Recycling Plastic Waste? NexantECA examines the technical, economic, and strategic aspects of thermal conversion (i.e., pyrolysis and hydrothermal treatment) technologies that are used to recycle mixed plastics waste. Selected developers of pyrolysis and hydrothermal treatment technologies are profiled and ranked under different criteria. An economic analysis of thermal conversion technologies, involving the production of feedstocks for olefins are provided for different geographic regions. In addition, the report includes an analysis of the plastic-based naphtha delivered cost competitiveness to Western Europe from the United States Gulf Coast, China, Japan, and Southeast Asia. An ethylene carbon intensity analysis is provided. Strategic and business considerations are also included in the report. 


The Authors..

Marisabel Dolan, Senior Consultant

Luann Farrell, Managing Consultant 



About Us - NexantECA, the Energy and Chemicals Advisory company is the leading advisor to the energy, refining, and chemical industries. Our clientele ranges from major oil and chemical companies, governments, investors, and financial institutions to regulators, development agencies, and law firms. Using a combination of business and technical expertise, with deep and broad understanding of markets, technologies and economics, NexantECA provides solutions that our clients have relied upon for over 50 years.


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