Award Date

May 2023

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Mechanical Engineering

First Committee Member

Yi-Tung Chen

Second Committee Member

Melissa Morris

Third Committee Member

Hui Zhao

Fourth Committee Member

Erica Marti

Number of Pages

95

Abstract

Microbial fuel cells (MFCs) are electrochemical devices that utilize microorganisms to convert organic matter into electrical energy. MFCs have been discussed to have potential application for sustainable wastewater treatment due to their ability to generate electricity while simultaneously treating contaminated water. To optimize MFC performance, numerical models can be used to understand the complex electrochemical and biological processes occurring in the system. In this study, a numerical model was developed to simulate the performance of MFCs under varying operating conditions and to investigate the performance of a MFC for treating wastewater fuel. More specifically, the MFC was modeled to oxidize acetate fed through the anode compartment and reduce oxygen fed through the cathode compartment. The results from the numerical model were compared to experimental data obtained from previously studied MFCs, and the model was found to accurately predict the previously studied MFC's performance, with the greatest percent difference between experimental and numerical values being 4.84%. The root mean square error (RMSE) was calculated to be 0.0271. The numerical model can be used to optimize the design and operation of MFCs, as well as to gain insights into the underlying significance of parameters such as temperature and pressure variation in microbial electricity generation. Performance analysis was determined with plotted current-voltage curves and power density curves. Results indicate that MFCs operating typically at higher temperatures and pressures have increased maximum power density. Furthermore, an increase in inlet concentrations of acetate in the anode compartment showed an increase in maximum power density for the MFC. The maximum power density achieved by the MFC when operating in parameters similar to the referenced experimental data was 2.5052 W/m^2. After raising the temperature in the simulation to 312 K (2.97% increase), a value of 2.8418 W/m^2 (13.4% increase) in maximum power density was observed. When only the pressure was increased to 2 atm (100% increase), the maximum power density increased to 2.8397 W/m^2 (13.4% increase). No significant changes to cell voltage or power density were apparent after increasing the oxygen flow rate in the cathode chamber. However, a change in maximum power density was noticeable after changing the acetate flow rate in the anode chamber. Furthermore, when only the inlet concentration of acetate was raised to 2 mol/m^3 (28.2% increase), the maximum power density increased to 3.6259 W/m^2 (76.7% increase).

Keywords

fuel cells; microbial fuel cell; microorganisms; model; simulation; wastewater

Disciplines

Environmental Engineering | Mechanical Engineering | Oil, Gas, and Energy

File Format

pdf

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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