Date of Award

Spring 2022

Degree Type

Non-Thesis Project

Degree Name

Master of Science in Engineering (MSE)

Department

Environmental Engineering

Committee Chair

Kumar Ganesan

First Advisor

Robin Bullock

Second Advisor

John Kirtley

Abstract

Hydrogen is an important energy carrier that has no carbon emissions when energy is extracted and also can be used as energy storage to increase the practicality of many renewable energy sources. The prominent methods of hydrogen production make use of fossil fuels, resulting in carbon emissions. Electrolysis is a lesser used technology for hydrogen production in which electricity splits water molecules into oxygen and hydrogen gases. If the electricity is sourced from renewable energies, this process releases little to no carbon and the resulting hydrogen is termed “green hydrogen.” While electrolysis and fossil fuel methods have comparable efficiencies of hydrogen production, the use of electricity results in electrolysis having a significantly higher cost. To make electrolysis feasible for large-scale hydrogen production, energy losses must be decreased to improve its efficiency. This study investigates the combined impact of electrolyte concentration and the application of a magnetic field on hydrogen production rates in alkaline electrolysis. Previous studies have shown the existence of an optimal electrolyte concentration that results in the highest rate of hydrogen production, typically around 30 wt% at room temperature. Other studies have shown that applying a magnetic field increases the conductivity of the electrolyte solution, which should increase the rate of hydrogen production. If the magnetic field is oriented to result in an upward Lorentz force, the resulting convection along with the Lorentz force encourages gas bubbles to dislodge from the electrodes, which reduces resistance and increases the active area of the electrodes. In this project, alkaline electrolysis was performed at room temperature using 1.8 V with KOH as the electrolyte. The flow rate of the electrolyte solution was fixed at 50 cc/min, and the volume of hydrogen produced was measured with a water displacement system. The electrolyte concentration was varied between 5 wt% - 30 wt%. At each selected concentration level, electrolysis was performed once without a magnet and once with a 1T magnetic field, created by permanent magnets oriented to create an upward Lorentz force. The results showed that at each concentration level, the magnetic field increased the rate of hydrogen production, with the largest increase at 10 wt%. The optimal concentration was approximately 30 wt% with no magnetic field, but with a 1 T magnetic field the optimal concentration was reduced to 10 wt%. Thus, applying a magnetic field calls for a reduction in electrolyte concentration, which results in cost savings, in addition to the benefit of a higher hydrogen production rate.

Comments

A project report submitted in partial fulfillment of the requirements for the degree of Master of Science in Environmental Engineering

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