Adsorptive Hydrogen Storage: Experimental investigations on thermal conductivity in porous media

Abstract

The objective of this work was to install and verify the Hot Disk TPS measurement setup for thermal conductivity measurements, and to carry out experiments on various porous materials. A literature survey on gas/solid porous media, with emphasis on the transport mechanisms and predictive models, was conducted. Special interest was taken in the widely-used Zehner/Bauer/Schlünder (ZBS) model for effective stagnant thermal conductivity of packed beds. Great care was shown in the determination of bed-properties such as porosity, because of the large effect it has on the effective thermal conductivity.The porous materials investigated were the Metal Organic Framework (MOF) hydrogen adsorbents Cu-btc (HKUST-1) and Fe-btc-xerogel. Large (⌀1.395mm) and smaller (⌀0.38mm) glass beads served as a reference material for preliminary tests and setup validations. In a later stage the Cu-btc and Fe-btc was experimentally investigated. Thermal conductivity measurements were conducted on a packed bed with air, nitrogen (N2) or helium (He) as fluid, in temperatures ranging from 243K