ScholarWorks@동국대학교

초록

Plastics with short lifespans, such as polyethylene (PE), generate substantial waste and environmental problems; however, conventional recycling is often inadequate due to material degradation and low yields of high-value products. Meanwhile, hydrogenolysis and hydrocracking have gained attention as alternative routes, but they still rely on externally supplied hydrogen, posing significant logistical challenges. To address this issue, we propose a tandem catalytic process for PE cracking with hydrogen supply by in situ dehydrogenation of decalin. Using this strategy, enhanced selectivity toward liquid products was achieved. To assess the economic and environmental viability, comprehensive techno-economic analysis (TEA) and life cycle assessment (LCA) were conducted for three process designs: Case tandem dehydrogenation and hydrocracking (TDH), Case separate dehydrogenation and hydrocracking (SDH), and Case hydrocracking using external hydrogen (HEH). Among these, Case TDH outperforms Cases SDH and HEH in both economic and environmental aspects. The minimum selling price (MSP) of gasoline was estimated at $3.5pergasolinegallonequivalent(GGE)forCaseTDH,comparedto$4.9/GGE and $4.4/GGE for Cases SDH and HEH, which incur higher costs in hydrogen recovery, and in the case of SDH, expenses from an additional dehydrogenation reactor. Case TDH also achieves a global warming potential (GWP) of 0.413 kg CO2 eq./kg gasoline, representing a reduction of 0.307 kg CO2 eq./kg gasoline relative to conventional gasoline. Overall, the tandem catalytic system provides a sustainable and economically viable pathway to advance circular economy objectives and mitigate plastic pollution by upcycling polyolefin-rich waste into valuable liquid fuels. © 2026 Elsevier B.V.

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