Catalytic and non-catalytic low-pressure hydrothermal liquefaction of pinewood sawdust, polyolefin plastics and their mixtures

Abstract

Hydrothermal co-liquefaction of biomass and polyolefin plastic feedstocks offers the advantage of potential synergistic reaction environments for producing liquid products of high fuel quality. In this present study, hydrothermal liquefaction and co-liquefaction of sawdust, low-density polyethylene and high-density polyethylene were investigated in a batch reactor from 350 °C to 450 °C and autogenic pressures below 30 bar. The novel low-pressure hydrothermal processing method was carried out with and without low-cost Ni–Cu/Al2O3 bimetallic catalyst. Thermal degradation of the sawdust started at 350 °C, whereas the plastics could only completely degrade at 450 °C, which was then chosen as the optimum reaction temperature. The catalysed process led to an increase in oil yield from the sawdust, with carbon enrichment by 16.3% and 22% deoxygenation. Furthermore, the catalyst promoted the formation of ketones and aromatic hydrocarbons, while consuming phenols and furfural in the sawdust-derived bio-oils. For the plastics, the catalyst, gave slight decreases in oils yield in favour of gas and/or char formation, with the promotion of in situ hydrogenation to enhance the yields of alkanes over alkenes. Results from hydrothermal co-liquefaction tests showed that synergistic interactions occurred between the degradation products of sawdust and the plastics. The observed synergy was further promoted by the presence of the catalyst, leading to dramatic deoxygenation of the oil products to produce hydrocarbon-rich fuels with less than 4 wt% oxygen contents (≈90% deoxygenation). This low-pressure hydrothermal co-liquefaction process is an efficient and cost-effective pathway for single-loop conversion of widely available biomass and plastics feedstocks into highly deoxygenated oils for use as sustainable fuels.

Publication DOI: https://doi.org/10.1016/j.jclepro.2023.139733
Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Chemical Engineering & Applied Chemistry
College of Engineering & Physical Sciences
College of Engineering & Physical Sciences > Energy and Bioproducts Research Institute (EBRI)
Aston University (General)
Additional Information: © 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Uncontrolled Keywords: Low-pressure co-hydrothermal liquefaction,Catalyst,Plastic wastes,Biomass,Hydrocarbon-rich fuel
Publication ISSN: 1879-1786
Data Access Statement: Data will be made available on request.
Last Modified: 10 Dec 2024 08:21
Date Deposited: 12 Aug 2024 09:22
Full Text Link: https://linking ... 95965262303891X
Related URLs: https://www.sci ... 891X?via%3Dihub (Publisher URL)
PURE Output Type: Article
Published Date: 2023-11-20
Published Online Date: 2023-11-13
Accepted Date: 2023-11-10
Authors: Onwudili, Jude a. (ORCID Profile 0000-0002-5355-9970)
Williams, Paul t.

Download

[img]

Version: Published Version

License: Creative Commons Attribution

| Preview

Export / Share Citation


Statistics

Additional statistics for this record