Gas Radiation Intensity

Fig. 2.19 Comparisons of gas radiation Intensity for three situations. A three-fold Increase with oxy-fuel firing Is caused of elimination of diluting N2.

Gas radiation intensity depends on (a) thickness of the gas radiation blanket or cloud, (b) concentration of triatomic molecules in the gas radiation cloud, and (c) average temperature of the gas cloud, including the flame. 

The convection heat transfer will be lower because lower volume means lower velocity. But convection is a minor fraction of the total heat transfer in furnaces above about 1200 F (650 C). Because about the same amount of chemical energy is released with oxy-fuel firing as with air-fuel firing, the adiabatic flame temperature as well as the triatomic gas radiation intensity from the poc of oxy-fuel firing will be higher. 

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