Long-distance hydrogen delivery using a toluene-based liquid organic hydrogen carrier system

Abstract

Abstract Liquid organic hydrogen carriers (LOHCs) can be used for long-term storage and long-distance transport of hydrogen. Here, hydrogen (H 2 ) is loaded into the organic molecule through a hydrogenation process and then unloaded through the reverse process (dehydrogenation). These organic molecules allow hydrogen to be handled at ambient conditions and transported using the existing crude oil-based infrastructure. In the present work, the system toluene-methylcyclohexane was identified as being one of the most promising LOHCs. Simulations for the hydrogenation and dehydrogenation processes were performed in Aspen Plus® for a 50 ktonne H 2 /year capacity. To increase the detail and reliability of the results, both reactions were modelled using kinetic laws and by-product formation was considered. The processes were optimized through heat integration, which enabled up to 60% savings of hot utilities. An economic analysis was held, from which the break-even price of hydrogen loading and release was found to be equal to 1.9 $/kg-H 2 .