Comment by api
16 hours ago
Biofuel makes more sense for airplanes. No conversion even necessary. You could fuel up a 737 with properly formulated biofuel and fly it now, though a lot of validation would be needed to be generally allowed especially for passenger flights.
If we want easier to produce biofuels then LNG aviation makes sense. We are flying LNG rockets already. You could go ahead and design LNG planes now and they’d emit less carbon even on fossil natural gas. Existing turbofan jet engines could be retrofitted to burn methane.
Biogas is incredibly easy to make to the point that there are pretty easy designs online for off grid biogas digesters you can use to run a generator. You can literally just turn a barrel upside down in a slightly larger barrel full of water, shit, and food waste, attach a hose to it, and as the inner barrel floats up it fills with biogas under mild pressure that you can plug right into things. May need to dry it for some applications since it might contain some water vapor but that’s not hard.
Industrial scale biogas is basically the same principle. Just large scale, usually using sewage and farm waste.
LNG rockets also mean “green” space launch is entirely possible.
LNG aviation does not make any more sense than H2 aviation. Even LPG does not make any sense since you neither can haul 16 bar fuel tanks, nor can you realistically maintain temperature for 1-2atm pressure. And any leak is not 'oh. look, a kerosene stain on tarmac', it's ready-made fuel-air explosion.
On the plus side we would be able to retire airport fire engines because they would never be able to get to a crash before it completely burns out.
You can't get much better than ready-made, for rocketry.
As if LNG is effectively more dense in flight than ordinary LPG, which doesn't need to be cryogenic to handle.
Armchair fuel experts do still provide food for thought though ;)