Document Type : Research Paper
Abstract
The transition from air to pure oxygen as a combustion oxidizer provides considerable benefits in flame temperature, fuel efficiency, and reduction of NOx and CO emissions, but it also raises safety, cost, and material integrity concerns. This study investigates the effects of varying combustion oxidizer from air to pure oxygen on flame temperature, emissions, thermal efficiency, and fuel savings across various fuels and combustion conditions. The results demonstrate that increasing the oxygen concentration in the oxidizer leads to higher adiabatic flame temperatures, enhanced combustion efficiency, and improved fuel economy, particularly in the transition from air-based to oxygen-enriched combustion. Among the fuels studied, acetylene exhibited the highest flame temperatures, making it more suitable for high temperature applications. Emission analyses reveal that oxygen enrichment reduces inert nitrogen in the oxidizer and increases the concentrations of important combustion products such as H2O and CO2, though CO levels rise due to high-temperature dissociation. NO formation peaks at intermediate oxygen levels due to optimal thermal conditions and nitrogen presence, then declines as nitrogen is replaced. Fuel utilization efficiency improves with increasing oxygen levels but shows diminishing returns above 70% O2, while fuel savings are more pronounced at higher exhaust temperatures. Overall, oxygen-enhanced combustion offers significant advantages in thermal performance and fuel efficiency, with optimal economic and operational benefits, achieved at moderate oxygen concentrations (30–50%). This study established that moderate oxygen concentration is suitable for reducing safety, cost and materials integrity concerns in retrofitted burners
