Liquid-Organic hydrogen carriers as endothermic fuels

Some cyclic molecules have been proposed as liquid-organic hydrogen carriers (LOHC) due to their ability undergo dehydrogenation reversibly, with ones containing nitrogen in the ring showing special stability. Here, we examined one of these, 1,2,3,4-tetrahydroquinoline (THQ), for use an endothermic fuel thermal protection hypersonic aircraft engines. The conversion and heats reaction were measured over a Pd-Al2O3 catalyst at 60 bar temperatures between 500 600 °C. Heats large 950 kJ kg−1 obtained, conversions greater than 80% was stable period least several hours no coking observed. For comparison, methylcyclohexane formed tars that quickly blocked reactor, even °C on this catalyst. These results suggest LOHC could serve alternative fuels cooling.