Discarded plastics can be converted to various fuels and chemicals to generate positive economic value instead of polluting the environment. In the past few years, pyrolysis has attracted much attention in the industrial and scientific communities as a promising versatile platform to convert plastic waste into valuable resources. However, it is still difficult to fine-tune an efficient and selective pyrolysis process to narrow the product distribution for a feasible commercial production. Furthermore, traditional plastic-to-fuels technology looks like another expensive way to burn fossil fuels, making no contribution to the plastic circular economy. By learning from the developed plastic-to-fuels technology, achieving the conversion of plastic waste into naphtha or plastic monomers that can be used for new plastic manufacturing in a closed-loop way is a more promising resource recovery pathway. However, there is no comprehensive review so far about achieving plastic waste recycling/upcycling by pyrolysis. This article will provide a critical review about the recovery pathways of plastic pyrolysis based on the various products (fuels, naphtha, hydrogen, and light olefins). It will overview the recent advances regarding plastic pyrolysis process and reactor design, introduce various recovery pathways based on the pyrolysis process, summarize process optimization and catalyst development, discuss the present challenges for plastic pyrolysis, highlight the importance and significance of creating a plastics’ circular economy, discuss the economic feasibility, the environmental impact, and outlook for future development for plastic pyrolysis. This review presents useful information to further develop and design an advanced pyrolysis process, with an improved efficiency, desirable product selectivity, and minimum environmental impacts. It is helpful to encourage more circular economy-oriented research aimed at converting waste plastics to naphtha and plastic monomers instead of simply producing fuels from the scientific communities of chemistry, energy, and the environment.
Bibliographical noteFunding Information:
Dr. Yuancai Lv is a teacher at Fuzhou University. He got her Ph.D from South China University of Technology, and M.S, B.S from Fuzhou University. He has been part of Center for Biorefining at University of Minnesota as a visiting scholar since 2019. Since 2012, he has been focusing on the development of environmental materials and the recycling of solid waste. So far, he has obtained 5 grants including the National Natural Science Foundation of China and Fujian Natural Science Foundation National, gained 5 Chinese invention patent and published 33 research articles. Currently, he has been the reviewers of several journals including Chemical Engineering Journal, Water Research, Journal of Hazardous Materials, Chemosphere and Energy & Fuel. His-interests involves synthesis of biomass materials, nitrogen fixation with non-thermo plasma and water pollution control .
Dr. Yanling Cheng is an adjunct associate professor at the University of Minnesota, USA, a professor at the Beijing Union University, China. She got her Ph.D from China University of Mining and Technology (Beijing), and M.S, B.S from Changchun University of Technology. Dr. Cheng's research focuses on value-added processes and systems development for various by-products, residues and wastes from food and agricultural productions, sustainable development, renewable energy and wastewater treatment. Dr. Cheng has published over 90 papers in refereed journals, co-authored three books, and holds 9 patents. She has supervised over 60 undergraduate and graduate students at Beijing Union University (BUU). She has received over 20 grants totaling over 10 million Chinese yuan in various funding for research, including major funding from Chinese Ministry of S&T, Beijing City Government, and industries since 2010. She has served as an editorial board member of 1 journal, and peer reviewer for several journals .
We acknowledge the financial support from National Natural Science Foundation of China (No. 21766019 , 21878137 ), China Scholarship Council (CSC) , Xcel Energy , Resynergi, and University of Minnesota MnDrive Environment Program (MNE12) and Center for Biorefining .
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- Circular economy
- Plastic waste