Catalytic microwave-assisted pyrolysis of plastic waste to produce naphtha for a circular economy

Abstract

Catalytic cracking of plastics into naphtha as a substitute for new plastic production has the potential to contribute to the plastic circular economy. However, mitigating catalyst deactivation in large-scale processes poses a significant challenge. Here, we demonstrate a remarkable improvement (4.3 × to 12.3 ×) in catalyst lifetime by utilizing hierarchical ZSM-5 catalysts compared to conventional analogues. Increasing the Brønsted acid concentration from 0 to 302 µmol/g enhances catalyst lifetime by over 46 × and boosts cumulative aromatic selectivity from 6 to 73%. Catalyst characterization reveals the development of significant voids after modification, enhancing molecular transport within the hierarchical ZSM-5. Economic analysis shows a pilot system with a 10 ton/day capacity yielding an annual profit of $344,999 and an 11.5% return on investment. Life cycle assessment indicates a reduction of 817.6 kg CO2 eq compared to traditional plastic-to-fuels technology. These findings advance the plastic circular economy and bring us closer to commercial implementation.