Here’s the meat and potatoes:
“If we assume that the entire quantity of jet fuel from the aircraft was injected into just one floor of the World Trade Center, that the jet fuel burnt with the perfect efficency, that no hot gases left this floor and that no heat escaped this floor by conduction.
We have found that it is impossible the jet fuel, by itself, raised the temperature of this floor beyond 280° C (536° F).
Listen closely: there were other things burning in addition to the jet fuel. M’kay? The jet fuel didn’t burn and then just leave the building pristine. When jet fuel burns, other stuff catches fire. That other stuff burns at higher tempratures. That is why the jet fuel was the accelerant, and the building was the fuel.