Bahlouli, Hussam A;
Alghamdi, Rasha;
Manos, George;
(2025)
Coke Characterization and Re-Activation Energy Dynamics of Spent FCC Catalyst in the Catalytic Pyrolysis of Polyolefins.
Catalysts
, 15
(9)
, Article 862. 10.3390/catal15090862.
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Abstract
Chemical recycling via catalytic pyrolysis is constrained by coke deposition and costly catalyst make-up. We investigate polypropylene (PP) and low-density polyethylene (LDPE) conversion over a spent FCC equilibrium catalyst (AXL) and, critically, quantify the re-activation energy landscape of the resulting coke. Using a semi-batch reactor (350 °C) and thermogravimetric analysis to 1100 °C combined with the Ozawa–Flynn–Wall method, we distinguish soft and hard coke under inert, oxidative, and sequential N2 to air regimes. LDPE yields mainly gas (70.7 wt%) with 5.5 wt% coke, whereas PP favors liquids (47.1 wt%) with 3.4 wt% coke. LDPE-derived coke is softer (71% of total; EA = 170 kJ mol−1 soft) than PP coke (60% soft; EA = 166 kJ mol−1), evidencing a more refractory PP residue. Oxygen lowers EA to ~155 kJ mol−1 for both polymers. We introduce a simple TGA-based “softness ratio” to guide regeneration severity and show that a refinery-waste FCC catalyst delivers selective plastic-to-fuel conversion while enabling energy-aware regeneration protocols. The framework directly supports scale-up by linking polymer structure, coke quality, and atmosphere-dependent re-activation energetics.
Type: | Article |
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Title: | Coke Characterization and Re-Activation Energy Dynamics of Spent FCC Catalyst in the Catalytic Pyrolysis of Polyolefins |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.3390/catal15090862 |
Publisher version: | https://doi.org/10.3390/catal15090862 |
Language: | English |
Additional information: | © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
Keywords: | pyrolysis; heterogeneous catalysis; Zeolites; Polyolefins; recycling; coke characterization |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
URI: | https://discovery.ucl.ac.uk/id/eprint/10213913 |
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