Continuous dehydrogenation of perhydro benzyltoluene in a three-phase stirred tank slurry reactor

Liquid organic hydrogen carriers (LOHCs) offer a promising solution for the safe and scalable storage and transportation of hydrogen. While efficient hydrogenation is less of a challenge, technical dehydrogenation poses multifold hurdles due to its endothermic nature, slow kinetics, and highly dynamic three-phase conditions. This study presents use of a continuous three-phase stirred tank slurry reactor for the dehydrogenation of the LOHC perhydro benzyltoluene as an alternative to conventional fixed-bed reactor concepts. The slurry reactor was evaluated systematically by variation of stirrer speed, feed rate, and operation temperature to identify operating regimes enabling stable and controlled hydrogen release under continuous three-phase conditions. Long-term operation under technically relevant temperature and pressure levels demonstrated stable operation with efficient phase separation, sustained catalyst activity, and minimal LOHC degradation. At 310 °C, a stable Pt-based hydrogen productivity of 2.7 g H2 g Pt −1 min −1 and a degree of dehydrogenation of approx. 40% were obtained, which indicates efficient catalyst utilisation when compared to other reported reactor concepts. Restart experiments showed that mechanical agitation effectively restores performance after shutdown. However, repeated rapid on-off cycles led to temporary deviations from steady-state. In addition, continuous hydrogenation was demonstrated using a catalyst basket configuration, achieving a degree of hydrogenation of 99.9% and confirming the general suitability of the CSTR configuration for reversible LOHC operation. Overall, the study positions the three-phase slurry CSTR as a complementary reactor concept emphasising catalyst efficiency, thermal homogeneity, and operational stability under continuous operation. • Continuous hydrogen release from liquid organic hydrogen carrier (LOHC) • Three-phase slurry reactor to overcome catalyst dewetting by using powder catalysts • Identification of operation parameters and limitations • Stable performance over 64 h time on stream alongside operational robustness • Full hydrogenation of LOHC in a single pass using a catalyst basket