Enhancing aromatics and olefins yields in thermo-catalytic pyrolysis of LDPE over zeolites: Role of staged catalysis and acid site density of HZSM-5

Inayat A, Inayat A, Schwieger W, Sokolova B, Lestinsky P (2022)

Publication Type: Journal article

Publication year: 2022

Journal

Fuel Elsevier

Book Volume: 314

Article Number: 123071

DOI: 10.1016/j.fuel.2021.123071

Abstract

The present work deals with the thermo-catalytic pyrolysis of LDPE (low-density polyethylene) in lab-scale one- and two-stage test rigs over HZSM-5 catalysts featuring different acid site densities. In the first part of this work, the influence of catalyst-to-feed ratio and temperature (in conjunction with the acid site density of HZSM-5) on the product distribution was studied with an aim to identify the optimum operating conditions for the enhanced production of aromatics and light olefins. For this purpose, one-stage thermo-catalytic pyrolysis was performed in which catalysts were mixed with LDPE pellets for in-situ catalysis. In the one-stage catalytic pyrolysis, the catalyst sample with the highest acid site density gave the highest concentration of aromatics (ca. 55%) in the pyrolysis oil with a mono-aromatics fraction of over 50% that consisted mainly of BTEX (benzene, toluene, ethylbenzene and xylenes) compounds. The highest C2-C4 olefins concentration (ca. 65%) in the pyrolysis gas was obtained when the sample with the lowest acid site density was used. In the two-stage catalytic pyrolysis (ex-situ catalysis), the concentration of aromatics in the pyrolysis oil reached over 77% with a mono-aromatics fraction of ca. 72% that contained mainly BTEX compounds, when the most acidic catalyst was used. When the catalyst with the lowest number of strong acid sites was employed, the high content of C2-C4 olefins in the pyrolysis gas remained almost independent of the reactor configuration. These findings might provide important new insights for the chemical recycling of plastic wastes.

Authors with CRIS profile

Alexandra Inayat Lehrstuhl für Chemische Reaktionstechnik Wilhelm Schwieger Professur für Technische Chemie (Reaktionstechnik)

Involved external institutions

Technical University of Ostrava / Vysoká škola báňská - Technická univerzita Ostrava CZ Czech Republic (CZ)

How to cite

APA:

Inayat, A., Inayat, A., Schwieger, W., Sokolova, B., & Lestinsky, P. (2022). Enhancing aromatics and olefins yields in thermo-catalytic pyrolysis of LDPE over zeolites: Role of staged catalysis and acid site density of HZSM-5. Fuel, 314. https://dx.doi.org/10.1016/j.fuel.2021.123071

MLA:

Inayat, Amer, et al. "Enhancing aromatics and olefins yields in thermo-catalytic pyrolysis of LDPE over zeolites: Role of staged catalysis and acid site density of HZSM-5." Fuel 314 (2022).

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