Theoretical adiabatic flame temperature

If the reaction is conducted both adiabatically and witli stoichiometric air. tlie resulting temperature is defined as tlie theoretical adiabatic flame temperature (TAFT). It represents tlie nia.xinuuii temperature tliat tlie products of combustion (flue) can acliieve if the reaction is conducted both stoichionietrically and adiabatically. For tliis condition, all tlie energy liberated from combustion at or near standard conditions (AH°c and/or AH°29s) appears as sensible heat in raising tlie temperature of tlie flue products, AHp, tliat is ... 

AHp = entlialpy change of the products as tlie temperature increases from 25°C to tlie theoretical adiabatic flame temperature... 

Let us reconsider the critical flame temperature criterion for extinction. Williams [25], in a review of flame extinction, reports the theoretical adiabatic flame temperatures for different fuels in counter-flow diffusion flame experiments. These temperatures decreased with the strain rate (ua0/x), and ranged from 1700 to 2300 K. However, experimental measured temperatures in the literature tended to be much lower (e.g. Williams [25] reports 1650 K for methane, 1880 K for iso-octane and 1500 K for methylmethracrylate and heptane). He concludes that 1500 50 K can represent an approximate extinction temperature for many carbon-hydrogen-oxygen fuels burning in oxygen-nitrogen mixtures without chemical inhibitors . 

Calculation of maximum theoretical (adiabatic) flame temperature in a combustion system. 

Calculate the theoretical adiabatic flame temperature of benzene (in air). The following standard heats of formation and heat capacity data are provided ... 

This expression may now be equated with the negative of the enthalpy of reaction (or combustion) to calculate the theoretical adiabatic flame temperature. This procedure is illustrated in the solution to this problem. 

Added benefits from preheating combustion air are faster burning, resulting in a hotter burner wall, and lower flue gas exit temperature. The desired prompt heat release is difficult to evaluate. An interesting facet of the available heat charts (figs. 5.1 and 5.2) is that the curves jc-intercepts (where available heat is zero) are theoretical adiabatic flame temperatures, or hot-mix temperatures mentioned earlier. For the... 

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