Is the flame temperature of a burning fuel affected by pre-heating the fuel? This page on Adiabatic temperatures helpfully lists the theoretical maximum temperatures that flames will reach under certain conditions for a number of fuels. They assume initial atmospheric conditions of 1 bar and 20 °C.

However, I am remain confused about what would happen if the fuels (and air) were pre-heated to temperatures close to these maximums before they were mixed and ignited.

Would the flame temperature then be higher than these listed maxima?

Would the reaction be slowed down by the higher temperature? (I understand that this might happen for exothermic reaction in equilibrium with an endothermic one, but I don't think that describes burning fuel.)

Is there some other mechanism that prevents the flame temperature from exceeding these minima?



This question was inspired by discussion on a Skeptics.SE question similar to this closed Chemistry.SE question about jet fuel and steel beams. I think it is sufficiently focussed and apolitical to be on-topic here. My background level is an ancient undergraduate science degree; I have forgotten more chemistry than I remember.
Yes and no: preheating a mix a little bit may increase the final temperature somewhat, but adding even more initial heat has a decreasing effect on the final temperature.

There are two competing factors that limit the final temperature in a closed system:


The total amount of energy as the sum of the initial amount of thermal energy and the chemical energy, divided by the thermal mass [mass times heat capacity] of the system, and 
The tendency for a reaction to be forced backwards by applying additional energy. 


For example, $\ce{2H2 + O2 -&gt; 2H2O}$ + 286 kJ/mole, but water dissociates more as the temperature rises. At 2,200 °C water is about 3% dissociated. At 3,000 °C  it is about 50% split, so half the chemical enegy is unavailable.

BTW, thermodynamically, a heat engine produces power based on the difference in temperature, so preheating a fuel-air mixture actually decreases efficiency, though it might be needed to vaporize the fuel (e.g. in Otto-cycle engine in cold weather).