Novel approach to upcycle waste plastics for reuse

May 24, 2021

PhD Graduate student Leilei Daid stands over his CMAP conversion machine wearing protective goggles. Plastic waste is a formidable environmental challenge. Existing thermomechanical recycling approaches are not sustainable and do not address greenhouse gas emissions. Our catalytic microwave-assisted pyrolysis (CMAP) technology is designed toachieve the conversion of waste plastics to high quality naphtha with the same technical characteristics as its fossil-based counterparts for new plastic production. The obtained naphtha product from our process can be used in the existing plastic production facility for new plastic manufacturing, which will help create a circular economy and minimize greenhouse emission.

Q: Why is this work important, both to you and to people in general? 

A: The plastic waste pollution is a serious issue everywhere, on the land and in the oceans, and is threatening our ecosystem and animal and human health. We need to take immediate actions to manage them. Developing a waste plastics-to-energy, fuels, chemicals and materials technique to upcycle waste plastics is an emerging topic. It is very promising and many major companies are extremely interested in this. We are closely collaborating with many of them and hoping to alleviate the plastic crisis in the near future with our microwave-assisted pyrolysis technology.  

Q: What has been the most rewarding aspect of your project so far? 

A: At the beginning of our project, we were mainly converting the waste plastics to transportation fuels, which seemed to be just another way to burn fossil fuels, and might not be completely green and sustainable. We strongly believe that the valuable plastic waste should be converted for high value naphtha production which is the feedstock for the new plastic manufacturing. Therefore, we have focused our work on developing the plastics-to-naphtha technology. After going through much effort, we have now developed a novel approach of combining two catalytic reforming zones, where the first catalytic reforming zone is intended to improve the cracking of polyolefins into C5-C12 olefins, and the second catalytic reforming zone is intended for the hydrogenation process to convert C5-C12 olefins to C5-C12 paraffins without high pressure or the use of external hydrogen for the naphtha production. The preliminary tests were very successful and very promising results (60-75% C5-C12 alkanes, 3-5% C5-C12 olefins, 5-15% mono-aromatics) were obtained as hypothesized. In this way, we are able to achieve the conversion of waste plastics to high quality naphtha that can be used for new plastic manufacturing, creating a circular economy and minimum greenhouse emission. 

Q: Is there a clear vision of what you hope your research project’s impact will be, and has that vision changed from the start of your project to present day?

A: The successful outcomes of this work will move our microwave-assisted pyrolysis technology closer to commercial implementation, which will help provide a sustainable way to utilize waste plastics, improve financial outlook of the plastic waste recycling industry, reduce fossil resource demand and CO2 emission, and thus reduce environmental impacts of plastic waste. We are looking forward to using our microwave-assisted pyrolysis technology to help build a sustainable circular plastic economy.