Hydrogen addition effects in a confined swirl-stabilized methane-air flame

• Published in: International journal of hydrogen energy Vol. 34; no. 2; pp. 1054 - 1062
• Main Authors: Kim, Han S., Arghode, Vaibhav K., Linck, Martin B., Gupta, Ashwani K.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 2009; Elsevier
• Subjects: Adiabatic flow; Applied sciences; Carbon monoxide; Combustion; Combustion of gaseous fuels; Combustion. Flame; Confined pre-mixed combustion; Diffusion flame; Diffusion flames; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Flame stability; Hydrogen enrichment of methane flames; Methane; NO x emission; Premixed flames; Stability; Strength; Swirl; Theoretical studies. Data and constants. Metering; Confined pre-mixed combustion; Hydrogen enrichment of methane flames; NO x emission; Diffusion flame; Flame stability; Swirl; Methane; Nitrogen oxide; Stability; Hydrogen; Flame temperature; Premixed flame; Combustion; Pollutant emission; Combustion velocity; NOx emission
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2008.10.034

The effect of hydrogen addition in methane-air premixed flames has been examined from a swirl-stabilized combustor under confined conditions. The effect of hydrogen addition in methane-air flame has been examined over a range of conditions using a laboratory-scale premixed combustor operated at 5.81
kW. Different swirlers have been investigated to identify the role of swirl strength to the incoming mixture. The flame stability was examined for the effect of amount of hydrogen addition, combustion air flow rates and swirl strengths. This was carried out by comparing adiabatic flame temperatures at the lean flame limit. The combustion characteristics of hydrogen-enriched methane flames at constant heat load but different swirl strengths have been examined using particle image velocimetry (PIV), micro-thermocouples and OH chemiluminescence diagnostics that provided information on velocity, thermal field, and combustion generated OH species concentration in the flame, respectively. Gas analyzer was used to obtain NO
x
and CO concentration at the combustor exit. The results show that the lean stability limit is extended by hydrogen addition. The stability limit can reduce at higher swirl intensity to the fuel-air mixture operating at lower adiabatic flame temperatures. The addition of hydrogen increases the NO
x
emission; however, this effect can be reduced by increasing either the excess air or swirl intensity. The emissions of NO
x
and CO from the premixed flame were also compared with a diffusion flame type combustor. The NO
x
emissions of hydrogen-enriched methane premixed flame were found to be lower than the corresponding diffusion flame under same operating conditions for the fuel-lean case.