Author

Mason J. Lang

Date of Award

2019

Degree Type

Thesis

Degree Name

Master of Science in Chemical Engineering

Department

Washkewicz College of Engineering

First Advisor

Jorge Gatica

Subject Headings

Chemical Engineering, Sustainability

Abstract

As landfills approach capacity and take up valuable land space, metropolitan areas have realized the need for waste disposal alternatives. Thus, there has been a widespread use of waste incinerators in Europe and the United States [1]; [2]. Although newer technology has made incinerators more efficient, there is an increasing interest in formulating `greener’ alternatives to incinerators. Gasification converts organic and carbonaceous materials into a combination of gaseous products known as “syngas,” or synthetic gas. This process greatly reduces the amount of hazardous emissions. The syngas produced by gasifiers has a wide range of uses, including their conversion into diesel, ethanol, methane, methanol and other synthetic fuels [3]. This research consists on an experimental assessment of Low-Temperature Wet Thermal Oxidation (WTO) [4] as a waste management alternative. Detailed experimental assessment and preliminary modeling of gasification technology to process polymeric waste into supply gas is completed here for a model polymer. While catalytic gasification of waste polymers has significance in a variety of engineering applications, it is of particular relevance to in-situ resource utilization (ISRU) and waste management in space exploration beyond low earth orbit (LEO). The substrates studied in our laboratory, Polyethylene and Cellulose, are both long chain organic polymers, and make up a substantial portion of both space and municipal waste composition. Although similar in nature, these substrates exhibit marked differences as it pertains to gasification and were therefore selected as model substrates. Experiments performed on polyethylene over a 5 wt% ruthenium catalyst supported by alumina are reported and analyzed in this paper. Analysis of gaseous products using a gas chromatograph with thermal conductivity detection provided data reflecting the conjunctive performance of all reactions. Application of reaction engineering parameter definitions and experimental data enabled the development of a model for the selectivity of reaction products. Kinetic parameters for the oxidation reactions of polyethylene were retrieved. This kinetic information, complemented by the kinetics of the gas-phase reactions (cf. Lange et al., 2018, and Lang et al., 2019), provide the foundation for a phenomenological model for the gasification of solid waste for sustainable living environments.

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