Ortho- to para-hydrogen catalytic conversion kinetics

Abstract

Hydrogen is a widely considered energy storage option. Hydrogen liquefaction allows for a substantial increase in volumetric energy density; the required conversion of ortho-hydrogen (o-H2) to para-hydrogen (p-H2) is however one of several challenges. This conversion requires a catalyst for sufficiently rapid kinetics, however available conversion data is sparse. To this end, a high throughput ortho-hydrogen (o-H2) to para-hydrogen (p-H2) conversion apparatus is detailed. This enables measurements at a controlled temperature of 77 K via the use of in-situ Raman Spectroscopy for quantitative determination of the ortho-para composition. Conversion kinetic data were acquired for a hydrous ferric oxide catalyst. These data were in reasonable agreement with limited existing literature, thus providing some validation for the use of conversion kinetic models, derived from such data, in hydrogen liquefaction design. Kinetic data was acquired using hydrogen provided via electrolysis; the effect of impurity (H2O) carry-over on conversion kinetics is considered.