Experimental Investigation of Premixed H2/CO/CNG/CO2 Blending Syngas Flames: Effect of Swirl Number and Equivalence Ratio
Ilker Yilmaz Omer Cam Harun Yilmaz
AbstractIn this study, effect of swirl number and equivalence ratio on combustion and emission behavior of premixed H2/CO/CNG/CO2 blending syngas flames was experimentally investigated in a swirl stabilized, laboratory scale combustor. At tested syngas mixture, composition (%30H2 %30CO %20CNG %20CO2 by volume) and H2/CO (moderate) ratio were kept constant while equivalence ratio (ϕ) and swirl number (SN) were changed 0.6-0.7 and 0.2-1.0, respectively. Combustion behavior of the tested gas composition was assessed via examining axial and radial temperature profiles, which are measured by K and B type thermocouples. On the other hand, emission profiles of O2, CO, CO2 and NOx were analyzed to define emission behavior. Results shows that increase from ϕ=0.6 to ϕ=0.7 raises the axial temperature gradients. The temperature difference in the flame front is more than the difference in the outlet. On the other hand, axial temperature declines from SN=0.2 to SN=1.0, gradually. Increase in the equivalence ratio reduces the CO emissions while it increases CO2 emissions. NOx emissions increase because of higher peak flame temperature at ϕ=0.7. Also, the conversion of CO to CO2 reduces the percentage of O2 at the exit of combustor. The SN=0.2 has the highest temperature in the axial direction, from the opposed point of view it has low temperature values in the radial direction. Because high swirl numbers allow to spread temperature in radial direction. For this reason, in desired situations, the usage of high swirl numbers can provide a more stable temperature distribution in all combustor.