What methods can increase fuel combustion temperature?

2025.10.03

Higher preheated air temperature $T_{air}$ can significantly raise flame temperature and radiation intensity.
Effective heat increases: $Q_{eff} = Q_{LHV} + \sum n_{air}\int_{T_0}^{T_{air}} c_{p,air} dT$

Reduce excess air coefficient $\alpha$
On the premise of complete combustion and safety, reducing $\alpha$ decreases $N_2$ dilution and flue-gas sensible heat loss. Trend: $\alpha \uparrow \Rightarrow T_{flame} \downarrow$ .
Oxygen-enriched combustion
Raising oxygen volume fraction $y_{O_2}$ (>21%) significantly reduces nitrogen dilution, increases $T_{ad}$ , and shortens the flame. Trade-offs: oxygen cost, $NO_x$ control, and higher lining heat load.
Improve mixing and combustion organization
Enhance turbulent mixing, proper swirl and staged air to reduce local oxygen deficiency and $CO$ , converting chemical energy to heat more completely.