Keywords

Hydrogen Storage, Adsorption, Physisorption, Silica Aerogel, Cryogenic, Solid-state storage

Abstract

Hydrogen has incontestably gained attention as one of the best alternative energy sources to fossil fuels due to its volatility, abundance and eco-friendly attributes. The classical methods for hydrogen storage in its gaseous or liquid forms such as high-pressure tanks or cryogenic temperatures display several challenges. Hence, the need to come up with innovative methods to store and transport it is imminent. Comparative studies have demonstrated that material-based hydrogen storage has proven promising in enhancing energy efficiency. However, material selectivity is the missing part of the puzzle to achieve optimal hydrogen storage performance. This dissertation introduces a novel material for cryo-adsorption hydrogen storage. In fact, Silica aerogel is among the lightest adsorptive materials with a high specific surface Area. It is ubiquitous and affordable. The transport equations of fluid flow in porous media with adsorption were formulated in details and the parameters characterizing the adsorption process were highlighted and studied. Additionally, the Dubinin-Astakhov model used to describe the equilibrium quantity adsorbed was validated experimentally and the data obtained from the experimental assessment revealed the potential of silica aerogel for solid state hydrogen storage. An increase of 44.6% of storage capacity using 99.61 grams of silica aerogel in 1L stainless steel tank subcooled to 77K and compressed at 100 bar. Then, the experimental setup was tested across a broad spectrum of temperatures and pressures. The system was subcooled to 298K, 196K, and 77K gradually using different coolants and brought to up to 100bar. The hydrogen uptake along with the equilibrium pressures were recorded to plot the isotherms for these temperatures. The results obtained corelated with the performance improvement of silica aerogel storage at lower temperatures and higher pressures. Also, the high specific surface area of the silica aerogel ~ 700m2/g compared to other adsorbent materials discussed in the study provides improvement to storage capabilities according iv to the Chahine’s rule.

Completion Date

2024

Semester

Fall

Committee Chair

Jayanta Kapat

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Format

PDF

Identifier

DP0029703

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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