I don’t know where the fuselage tanks are. I would guess they are in the cargo hold, probably in the general area of the wing root.
I don’t know where you are getting your numbers, but they make no sense.
The total fuel capacity for a 737-700 is about 6900 gallons. Roughly 1300 gallons can be carried in each wing. They didn’t ignite because they apparently weren’t punctured by flying engine parts.
What the heck is the “compressed air combine engine theory”? That phrase makes no sense.
It should be fairly obvious to anyone who knows anything about turbine engines that the compressor started losing parts, which destroyed the rest of the engine, and the containment shroud failed catastrophically.
http://simviation.com/rinfo737.htm
This site here says that the 737 holds 6,875 gallons or 26,025 liters of fuel max. cap. which weighs about 47,000 pounds or over 23 tons.
That means each wing is weighted down by 23,000 pounds at takeoff, not 7,000 pounds. (in jet fuel gallons to pounds).
I want to disprove this new theory that airlines have been using Tesla technology of compressed air turbines instead of fuel, but charging us for the fuel.