Experimental determination of the hydrogenation/dehydrogenation - Equilibrium of the LOHC system H0/H18-dibenzyltoluene

Liquid organic hydrogen carrier (LOHC) systems store hydrogen through a catalystpromotedexothermal hydrogenation reaction and release hydrogen through an endothermalcatalytic dehydrogenation reaction. At a given pressure and temperature theamount of releasable hydrogen depends on the reaction equilibrium of the hydrogenation/dehydrogenation reaction. Thus, the equilibrium composition of a given LOHC system isone of the key parameters for the reactor and process design of hydrogen storage andrelease units. Currently, LOHC equilibrium data are calculated on the basis of calorimetricdata of selected, pure hydrogen-lean and hydrogen-rich LOHC compounds. Yet, real reactionsystems comprise a variety of isomers, their respective partially hydrogenatedspecies as well as by-products formed during multiple hydrogenation/dehydrogenationcycles. Therefore, our study focuses on an empirical approach to describe the temperatureand pressure dependency of the hydrogenation equilibrium of the LOHC system H0/H18-DBT under real life experimental conditions. Because reliable measurements of the degree of hydrogenation (DoH) play a vital role in this context, we describe in thiscontribution two novel methods of DoH determination for LOHC systems based on 13C NMRand GC-FID measurements