Hydrogen storage and release characteristics of polycyclic aromatic by-products for LOHC systems

Abstract

The potential uses other than fuels for heavy oil by-products, such as light cycle oil (LCO) from fluid catalytic cracking, has to be developed owing to environmental issues. Herein, we report the hydrogen storage and release characteristics of simulated light cycle oil (Sim-LCO) studied by hydrogenation and dehydrogenation, respectively, over a platinum catalyst. The H2 storage/release behaviors of Sim-LCO were compared to those of the toluene/methylcyclohexane pair and equilibrium conversions. The aromatics in Sim-LCO showed lower turnover-frequencies and higher activation energies than toluene for hydrogenation. However, the 2-ring aromatics showed a higher H2 storage capacity than toluene. Sim-LCO could store H2 at its theoretical capacity (5.27 wt%), and release H2 at > 5 wt% during dehydrogenation. Therefore, LCO is a potential low-cost H2-lean liquid organic hydrogen carrier. However, the dehydrogenation activity of the platinum catalyst should be improved when the equilibrium conversion is considered.