Novel Catalyst for Single Step Conversion of Plastic Waste with 85% Olefin Yield

Andreas Eschenbacher, Robin John Varghese, Evangelos Delikonstantis, Oleksii Mynko, Farnoosh Goodarzi, Kasper Enemark-Rasmussen, Jogchum Oenema, Mehrdad SeifaliAbbas-Abadi, Georgios Stefanidis, Kevin M. Van Geem

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review

Abstract

The interest in the chemical recycling of plastic waste via thermochemical processes is on the rise since it bears the potential to promote a carbo-circular economy. Within this study, the catalytic fast pyrolysis of polyolefinic waste streams was investigated to recover valuable base chemicals at high selectivity. We compare the energy demand and carbon footprint of this direct route with other state-of-the-art processes. Different feeds, (virgin and post-consumer polyolefins), catalyst/feed ratios, and reaction temperatures were tested in a micropyrolysis reactor coupled to two-dimensional gas chromatography. HZSM-5 zeolite was used as catalyst for upgrading the pyrolysis vapors. After a steam-treatment at 800 °C, a phosphorus-stabilized microporous HZSM-5 and its desilicated version showed high selectivity for production of valuable base chemicals when upgrading pyrolysis vapors at 600 °C, with ~80% C2-C4 olefins and ~5% aromatics produced from virgin PE. Increasing the reaction temperature from 600 to 700 °C, increased the aromatics yield to ~10 wt. % while producing similarly high overall yields of C2-C4 olefins. Processing post-consumer mixed polyolefin resulted in 5-10 wt. % lower olefins yield than using virgin PE but produced ~5 wt. % more aromatics due to its contamination with PS and PET. While parent HZSM-5 rapidly deactivated for repeated runs owing to its high coking propensity, phosphorus-modified and steamtreated HZSM-5 showed almost no deactivation during 130 runs with stable conversion towards C5+ aliphatics and high C2-C4 olefins selectivity with a 70% reduction in coke deposition. The performance of this direct olefins production route was further evaluated in a plantwide context. It was found that it requires ~38% lower energy input than the step-wise counterpart (plastics pyrolysis followed by pyrolytic oil steam cracking), while it results to at least an order of magnitude lower carbon footprint as compared to peer state-of-the-art processes.

Original languageEnglish
Title of host publicationProceedings of the 2022 AIChE Spring Meeting and 18th Global Congress on Process Safety
PublisherAmerican Institute of Chemical Engineers
Publication date2022
Pages313-341
ISBN (Electronic)978-171387086-9
Publication statusPublished - 2022
Event34th Ethylene Producers Conference 2022: Topical Conference at the 2022 AIChE Spring Meeting and 18th Global Congress on Process Safety - San Antonio, United States
Duration: 10 Apr 202214 Apr 2022
Conference number: 34

Conference

Conference34th Ethylene Producers Conference 2022
Number34
Country/TerritoryUnited States
CitySan Antonio
Period10/04/202214/04/2022
SeriesAIChE Ethylene Producers Conference Proceedings
Volume2022-April
ISSN1066-1557

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