That molten steel was the result of an entirely different reaction and had nothing to do with jet fuel.
Oxidation of iron by air is not the only EXOTHERMIC reaction of iron (= structural steel which is about 98 % Fe, 1 % Mn, 0.2 % C, 0.2 % Si.....). There is at least one additional reaction of iron with the capability of keeping the rubble pile hot and cooking!
The reaction between IRON AND STEAM is also very EXOTHERMIC and fast at temperatures above 400 deg C. This reaction produces Fe3O4 AND HYDROGEN. It is the classic example of a REVERSIBLE REACTION studied in Chemistry labs at high school. But believe it or not, back at the turn of the century, the reaction of iron and steam was used as an industrial process for the manufacture of hydrogen.
I think iron and steam could have reacted in this way (at least for a while) and generated a lot of heat. What is more, the hydrogen released would have been converted back to water by reaction with oxygen, thereby generating even more heat. In this case spraying water on the rubble pile was like adding fuel to a fire!
Now add in gypsum reactions with H2 and CO and we have a great source of SO2 and/or H2S to sulfide the steel!
Perhaps the endless spraying of water on the rubble pile was not such a good idea!
In the usual lab experiment on the reversible reaction of iron and "steam", nitrogen (or some inert gas) is bubbled through water to create a gas stream saturated with water vapor at room temperature. This gas is then allowed to flow into a glass tube about 1 meter long containing iron in an inert boat at its center. This assembly is heated in a tube furnace to some desired temperature, say 500 deg C. The hydrogen/ nitrogen gas mixture is collected at the outlet of the tube furnace.
In the industrial process the feed gas might also be "water gas" which is a mixture of CO and water vapor. The outlet gas contains mostly H2 and CO2.
I am sure there was plenty of water vapor AND oxygen in the void spaces in the rubble pile. This is the "steam" I am referring to.
Please remember that the recovered pieces of structural steel were heavily OXIDIZED as well as sulfided. The most important oxidizing agents available in the rubble pile were obviously O2 and H2O.
The rubble pile was not only inhomogeneous with regard to its composition, it was inhomogeneous with regard to its temperature. This was due to localized chemical reactions. Such reactions were capable of generating high temperatures in these localized hot spots.
The demolitionists much beloved thermite is a good example, BUT NOT THE ONLY EXAMPLE. AND THERE IS ABSOLUTELY NO PROOF WHATSOEVER THAT THERMITE, THERMATE, SOL-GEL NANO-THERMITE WAS EVER PRESENT AT THE WTC SITE!!!!!!
It is irrelevant whether or not the steam was wet or dry, that is a chemical engineering notion only of interest in a closed and controlled system, usually under high-pressure, such as a steam generator in a power station.
Water vapor was present in the rubble pile and water vapor reacts with iron releasing HYDROGEN.
ITS CALLED A CORROSION REACTION:
METAL + WATER = METAL OXIDE + HYDROGEN
WHEN IT HAPPENED AT THREE MILE ISLAND IT CREATED A HYDROGEN BUBBLE