Adsorption Based Hydrogen Storage System; Multiscale Approach and Mathematical Model
Agnieszka Truszkowska1, Christopher Loeb1 and Goran Jovanovic1
1Oregon State University, Department of Chemical, Biological, and Environmental Engineering, Corvallis, OR 97330, USA
In an effort to reduce CO2 emission arising from sources of current forms of transportation energy, hydrogen is sought as a potential replacement to major fossil fuels. However, deploying hydrogen into vehicles faces considerable challenges, one of which is efficient storage solution that would meet practical performance and cost criteria. Adsorption based storage systems are one of the promising storage solutions, which are currently under intensive development.
Adsorption based storage systems are typically made of materials like activated carbon and MOF-5; hence, they are considered a porous structure. These materials often meet gravimetric storage requirements, but their volumetric capacities become sufficient only at cryogenic conditions. Operation of hydrogen storage system in cryogenic region creates opportunities for many design solutions.
In this paper we propose a numerical tool based on multiscale mathematical modeling, which supports experimental effort in performance characterization of cryogenic hydrogen adsorption storage system.
Mathematical model and corresponding numerical simulation techniques provide a tool capable of numerically describing hydrogen storage phenomena on an arbitrary number of structural levels in three dimensions.
Numerical package provides users with essential properties of porous hydrogen storage media: permeability, effective diffusivity and effective conductivity of the system. These mixed properties are based on material, process, and geometric characteristics of the storage system.
Results of numerical simulation enable a valid analysis of system performance at each scale and provide means for further optimization. We also propose the characteristic times analysis as one of the modeling approaches which informs design development of the hydrogen storage system.
In addition we provide validation of the mathematical model and the results of numerical simulation with experimental data collected on adsorption media (activated carbon and MOF-5) in our hydrogen storage laboratory.