Term of Award

Spring 2025

Degree Name

Master of Science, Mechanical Engineering

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Mechanical Engineering

Committee Chair

Prakashbhai R. Bhoi

Committee Member 1

Sevki Cesmeci

Committee Member 2

Marcel Ilie

Abstract

The ongoing impact of technological advancement and innovations of modern industries makes climate change more formidable obstacles to creating safe and sustainable environment. The substantial dependence on fossil fuels has markedly exacerbated this issue, mainly through the release of greenhouse gases (GHGs), which intensify global warming. A vital measure to alleviate climate change is reducing reliance on fossil fuels by investigating feasible alternatives. Among the various renewable energy sources such as solar, wind, tidal, and geothermal, biomass emerges as a viable and sustainable alternative. Its capacity to generate carbon-based fuels and chemical compounds while sustaining a closed carbon cycle renders it an attractive alternative in the shift towards more sustainable energy. Co-gasification converts waste plastic —major environmental issues—as well as biochar, a carbon-neutral biomass-derived material, into syngas with high methane and hydrogen concentration. This study simulated waste mixed plastics in municipal solid waste using household samples: uncapped PET (water bottles), HDPE (milk jugs without cap), LDPE (trash bags), PP (disposable cups), PS (styrofoam cups and cutlery) and others (compact discs made of polycarbonate). Combining the real plastic samples in ratios comparable to waste mixed plastics found in municipal solid waste provides realistic data for scale-up purposes. Two water (steam) flow rates (3 mL/min and 5 mL/min) and four plastics-to-biochar ratios ( 0/50, 15/50, 25/50, 50/50), and three temperatures (800°C, 900°C, 950°C) were examined using a fixed bed batch reactor to evaluate the performance in terms of syngas composition and co-gasification efficiency of pine biochar and waste mixed plastics. At 800°C, plastics-to-biochar ratio of 0.5, and a steam flow rate of 3 mL/min, the syngas was primarily consisted of methane (62.5% CH4) and hydrogen concentration of 21.2% vol., resulting in the lowest co-gasification efficiency of 40.24%. At 900°C, the syngas composition observed with 47.5% vol. methane and 32% vol. hydrogen, yielding the maximum co-gasification efficiency of 64.34%. At 950°C, the hydrogen concentration further increased to 42.9% vol., while methane significantly decreased to 23.8% vol., resulting in a low efficiency of 42.28%. These compositions and findings highlight the optimal temperature, plastics to biochar ratio and steam flow rate for maximizing the syngas composition and overall gasification efficiency.

Research Data and Supplementary Material

No

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Available for download on Wednesday, April 14, 2027

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