Fueling of the big aircraft is done through sealed hoses - releasing a
lot less fumes than you get when filling up your family car.

Not true---think about it----while that fuel is going into the tank, something
has to come out of the tank. Look into tank vent valves used on large single
point refueled aircraft. I remember a vent valve failing on a B-58 and saw the
side of the fuselage that was blown out by the pressure build up. Mac



At service stations, here is what happens. The car fills, and the
coaxial hose catches the car's exiting vapor and pushes it into the
tank that now has 20 gallons less liquid than it did before. If
there's any extra vapor to vent, there's a sort-of open air water
heater on the building roof. It has a pilot light and gets combustion
air drafted in from the below-ground tanks vents. (There are other
schemes but this got you ""free"" hot H2O...)

The tanker arrives. The {say} 8000 gallons of gasoline is drained
into the underground tank. That displaces 8000 gallons of vapor
which is shoved into the now liquid-empty but vapor-full tanker.

The tanker goes back to the marketing terminal and gets refilled.
It passes that 8Kgal of vapor to the terminal. There, there is a
"vapor recovery unit" - a stripped down micro refinery that mixes
the vapor with base stock ("lean oil" I doono why that name), giving
you liquid almost-gasoline. Say you get 1 gal of liquid for every
100 of vapor.

That a-g is then injected in small fractions into #2 Diesel and/or
#2 Heat{ing Oil}. In doing so, it lowers the flash point from oh
120F to 115.

That's how vapor recovery works in the car biz. Aircraft? Well, vice
automotive volumes, and Jet-A; avgas is a penny vs the DoD budget
worth, so skip that. (Even so, Southern Califunny may regulate; I
doono..). As for JetA, I never saw V-R in action when I worked on
such at CLE but maybe it's now at LAX etc. The basics would be the
same. I suspect they would use the recovered vapor in ramp lice,
not aircraft, as its characteristics will vary somewhat...
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