Problem: Thermal pyrolysis of plastic wastes leads to high M.W. hydrocarbons (Waxes) Scope: In-situ catalytic upgrading of py-oil Target: Naphtha range hydrocarbons Why Naphtha Catalytic upgrading of plastic wastes fast pyrolysis oils towards naphtha range hydrocarbons P. Soldatos1, A. Margellou1, S. Torofias1, A. Lemonidou2, K.Triantafyllidis1,3,* 1 Department of Chemistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece. 2 Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece. 3 Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, 10th km Thessaloniki-Thermi Rd, P.O. Box 8318, 57001 Thessaloniki, Greece *e-mail: ktrianta@chem.auth.gr INTRODUCTION 1 Abbas-Abadi et al., PECS (2023), https://doi.org/10.1016/j.pecs.2022.101046 2 Tan et al., ChemSusChem (2022), https://doi.org/10.1002/cssc.202200522 3 Al-Salem et al., WasMan (2009), https://doi.org/10.1016/j.wasman.2009.06.004 This research has received funding from the European Union’s Horizon Europe research and innovation programme under the HORIZON-CL4-2021-TWIN-TRANSITION-01 grant agreement No 101058412. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or HADEA. Neither the European Union nor the granting authority can be held responsible for them. References Each year, approx. 400 mil. tons of new plastics are produced, with around 3/4 being common thermoplastics (PE, PP, PET, PS, and PVC). However, less than 20% of Plastic Solid Waste (PSW) is recycled 1,2. Solution? Fast pyrolysis present a promising alternative, effectively handling PSW contamination & heterogeneity, leading to the recovery of valuable chemicals (mainly hydrocarbons) in the form of pyrolysis oil (py-oil) and gases 3 . <20% Recycled ~25% Incinerated ~60% Landfilled Microplastics Leaching GHGs Aim of this work Steam Cracker Petroleum Naphtha Plastics py-oil C2H4 C3H6 Polymerization New Plastics EXPERIMENTAL Characterizations Fast Pyrolysis Results 0 2 4 6 8 10 12 14 16 18 20 3 8 13 18 Yield (wt.%) Carbon Number Beta (12.5) Beta (37.5) ZSM-5 (11.5) ZSM-5 (40) ASA Thermal Naphtha 0 20 40 60 80 100 20 120 220 320 420 520 620 Mass (%) Temperature (oC) LDPE PP HDPE PET PS -50 -40 -30 -20 -10 0 220 320 420 520 620 DTG (%/min) Temperature (oC) *Measurements cond.: 20-700 oC, 10 oC/min, Ν2 Thermal decomposition of polymers TGA/DTG Fixed-Bed Catalytic Fast Pyrolysis (CFP) Reactor LDPE PP PET PS VIRGIN PLASTICS H-ZSM-5 (Si/Al=40, 11.5) H-Beta (Si/Al=12.5, 37.5, 150) H-MOR (Si/Al=10) SiO2-Al2O3 (Si/Al=0.5) CATALYSTS H-FER (Si/Al=10) H-USY (Si/Al=6) Ni/Al2O4, red 10%Ni-W/ZrO2 Catalysts SBET (m2/g) Smicro (m2/g) Vtotal (cm3/g) Vmicro (cm3/g) Brönsted acidity (μmol Py/g) Lewis acidity (μmol Py/g) B/L ZSM-5 (40) 437 332 0.325 0.142 161 21 7.6 ZSM-5 (11.5) 424 349 0.229 0.142 432 104 4.1 BETA (12.5) 596 376 1.263 0.153 177 229 0.8 BETA (37.5) 670 351 1.339 0.145 135 65 2.1 ASA 442 0 0.702 0 38 371 0.1 NiAl2O4, red 97 - 0.147 - - 23 -- Catalysts properties 0 10 20 30 40 50 60 70 80 90 100 LDPE PP PS PET Yield (wt.%) Py-oil Waxes Gases Mass balances of Plastics Thermal Pyrolysis Catalysts screening in LDPE degradation • All acidic aluminosilicate catalysts enhance LDPE decomposition • ASA (Lewis acidity) exhibits similar behavior with strongly acidic zeolites • Among zeolites, ZSM-5 (Si/Al=40) & Beta (150), with fewer but stronger acid sites, show slightly better reactivity ZSM-5 (40) decreased Tmax,DEG ~80 oC Key Parameters Fixed-Bed Fast Pyrolysis (Thermal experiments) LDPE LDPE 450 oC 0 10 20 30 40 50 60 70 80 90 100 ZSM-5 (40) Beta (37.5) Beta (12.5) ZSM-5 (11.5) ASA Thermal Yield (wt.%) Py-oil Waxes Gases 0 20 40 60 80 100 ZSM-5-450 ZSM-5-450 ZSM-5-450 Yield (wt.%) Plastic/Catalyst : 5/1 Thermal pyrolysis of PE/PP predominantly produces high M.W. HCs (Waxes/C16 +) GC-FID LDPE-450 oC Waxes Fixed-Bed Catalytic Fast Pyrolysis Carbon Number Distribution