Why is jet fuel used as an aviation fuel in preference to dihydrogen gas? Does it make sense in terms of the energy yield?

Question

Why is jet fuel used as an aviation fuel in preference to dihydrogen gas?  Does it make sense in terms of the energy yield?

Peyton Adams · Accepted Answer

Consider the mass of hydrogen, versus the mass of aviation fuel (which to a first approx. is kerosene).

#H_2(g) + 1/2O_2(g)rarrH_2O(g), DeltaH_"rxn"=-286*kJ*mol^-1# #C_12H_26+18(1)/(2)O_2rarr12CO_2+13H_2O# #DeltaH_"rxn"=-3506*kJ*mol^-1# Dihydrogen provides a lot more energy per gram, but how do you store the hydrogen on board? In the lab, hydrogen gas bottles are large steel cylinders (roughly 100 kg) that you can simply lift. Moreover, using compressed gas in an airplane raises safety concerns (as does using compressed gas bottles in the lab, of course). However, carburettor technology for the ICE with liquid fuels is a fairly mature field; the gas supply would have to be regulated (reduced to a sensible pressure) and supplied to the combustion engine on a gas tight loop - all large (and heavy) engineering requirements.

Cooper Adams · Answer

undefined Jet fuel is preferred over dihydrogen gas as an aviation fuel because it has a higher energy density, making it more efficient for powering aircraft. Dihydrogen gas has a lower energy density and requires larger storage tanks, making it less practical for aviation use despite its clean combustion properties. Therefore, in terms of energy yield and practicality, jet fuel is the preferred choice for aviation fuel.