Experimental Study of H2 and/or N2 Addition Effects on CO/CO2-Air Flames using a Combustion Diagnostic System

In this work, the effects of H-2 (0-8 vol%) addition, N-2 (0-8 vol%) addition, and H-2/N-2 (4 vol%/4 vol%) addition in CO/CO2 gas flow on the flame structure, flame temperature, and CO2 concentration in flames were investigated. A combustion diagnostic system based on tunable diode laser absorption spectroscopy (TDLAS) was utilized to measure the flame temperature and CO2 concentration in flames simultaneously. This work simulated the combustion of converter gas (CO/CO2/H-2/N-2) in an industrial turbulent partly premixed burner. The results show that with the addition of H-2(0-8 vol%) in CO/CO2 flame and the addition of H-2(4 vol%) in CO/CO2/N-2(4 vol%) flame, the flame length is longer than that with the same volume addition of N-2. The added reactions caused by the addition of H-2(4 vol%) in CO/CO2 flame and CO/CO2/N-2(4 vol%) flame result in a larger high-temperature reaction zone. The enrichment of H-2(8 vol%) in CO/CO2/H-2(4 vol%) flame, the dilution of N-2(0-8 vol%) in CO/CO2 flame, and the dilution of N-2(4 vol%) in CO/CO2/H-2(4 vol%) flame make little difference on the high-temperature reaction zone. The promotion effects of H-2 addition on CO2 formation are more prominent than the dilution effects of N-2 addition on CO2 concentration in flames.

Automated summary

This study investigated the effects of H-2, N-2, and H-2/N-2 additions on flame structure, temperature, and CO2 concentration in CO/CO2 gas flow. Results showed that H-2 addition lengthened the flame and expanded the high-temperature reaction zone, while N-2 addition had the opposite effect. Additionally, the promotion effects of H-2 on CO2 formation were more significant than the dilution effects of N-2 on CO2 concentration in flames.