Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Analysis of water transport phenomena in thin porous media of a polymer electrolyte membrane fuel cell(Montana State University - Bozeman, College of Engineering, 2018) Battrell, Logan Robb; Chairperson, Graduate Committee: Ryan Anderson; Aubree Trunkle, Erica Eggleton, Lifeng Zhang and Ryan Anderson were co-authors of the article, 'Quantifying cathode water transport via anode humidity measurements in a polymer electrolyte membrane fuel cell' in the journal 'Energies' which is contained within this thesis.; Ning Zhu, Lifeng Zhang and Ryan Anderson were co-authors of the article, 'Transient, spatially resolved desaturation of gas diffusion layers measured via synchrotron visualization' in the journal 'International journal of hydrogen energy' which is contained within this thesis.; Virat Patel, Ning Zhu, Lifeng Zhang and Ryan Anderson were co-authors of the article, '4-D imaging of the desaturation of gas diffusion layers by synchrotron radiography' submitted to the journal 'Journal of power sources' which is contained within this thesis.This thesis explores and quantifies water transport related to the desaturation of the thin porous layer known as the Gas Diffusion Layer (GDL) associated with Polymer Electrolyte Membrane (PEM) fuel cells. The proper management of water within this layer is critical to optimal fuel cell performance. If there is not enough water, the membrane can become dehydrated, which leads to poor cell performance, but if too much water accumulates or becomes flooded, gas transport is restricted, which also lowers performance and can potentially lead to total cell failure. Understanding the desaturation of this layer is thus key to obtaining and maintaining optimal fuel cell performance. This behavior is explored both at the macroscale, through the quantification of the removal of excess water from an active fuel cell, as well as at the micro-scale, through the use of synchrotron X-ray computed tomography (X-ray CT) to visualize and quantify the desaturation of an initially flooded GDL. The macro-scale investigation extends the previously developed qualitative Anode Water Removal (AWR) test, which functions to identify when poor PEM fuel cell performance is due to excess water, to a diagnostic protocol that quantifies the amount of water being removed by the test through an analysis of the anode pressure drop. Results show that the protocol can be applied to a variety of fuel cell setups and can be used to quickly quantify water management capabilities of novel GDL materials. The microscale investigations show that while both convection and evaporation play a role in the desaturation, evaporation is required to fully desaturate the GDL. Additionally, the microscale investigation allows for the spatial segmentation of the GDL to identify local desaturation rates and temporal saturation profiles, which show that the overall desaturation of the GDL is a heterogeneous process that depends on initial conditions, flow field geometry and the natural anisotropy of the material. Results show that future control strategies and modeling studies will need to expand their investigated domains in order to accurately capture the fully heterogeneous nature of this process.Item Adsorption capacity of SAPO-34 and ZSM-5 zeolites determined by breakthrough experiments(Montana State University - Bozeman, College of Engineering, 2016) Ilic, Boris; Chairperson, Graduate Committee: Stephanie WettsteinAlthough it has been known for over 50 years that zeolite frameworks are flexible, it has been only of recent that a systematic investigation into this phenomenon has begun. An area that has not been significantly explored is the affect that zeolite flexibility may have on adsorption capacities. In order to explore this, a flow system was built and assembled, and the system performance was verified by replicating literature ZSM-5/isobutane, ZSM-5/n-hexane, and SAPO-34/methanol adsorption isotherms. Different packing schemes (powders, mixtures, pellets) were studied and corresponding adsorption capacities were evaluated for accuracy and precision. It was found that zeolite powder pressed into pellets led to the lowest deviation from literature values and that larger crystal sizes may also lead to more accurate values. While further investigation into packing methods is recommended, the relatively accurate adsorption capacities that were acquired suggests that the established flow system has been built and calibrated correctly, and that further adsorption experiments probing the flexibility of the zeolite structure can begin.Item Selective permeation through modified vinylindene fluoride membranes(Montana State University - Bozeman, College of Engineering, 1975) Zavaleta, RonanthItem The separation of oxygen from air using commercial, plasticized, and nonplasticized polymeric membranes(Montana State University - Bozeman, College of Engineering, 1985) Mus, Mark DavidItem Temperature effects on the separation of isomeric xylenes using the pervaporation process(Montana State University - Bozeman, College of Engineering, 1985) Downs, William BlaineItem Separation of Hâ‚‚ from Nâ‚‚ by selective permeation through polymeric membranes(Montana State University - Bozeman, College of Engineering, 1976) Heyd, Robert LeoItem The separation of SOâ‚‚and Nâ‚‚ by permeation through modified vinylidene fluoride membranes(Montana State University - Bozeman, College of Engineering, 1973) Seibel, Dennis RobertItem Separation of isomeric xylenes by permeation through modified plastic films(Montana State University - Bozeman, College of Engineering, 1972) Sikonia, John GeorgeItem Effects of water vapor on the separation of methane and carbon dioxide by gas permeation through polymeric membranes(Montana State University - Bozeman, College of Engineering, 1982) Paulson, Gerald Thomas