The characteristics of pollutant emission for non-premixed flames with LCG 8000 and LCG 6000 represented as low calorific gases were investigated by numerical simulation. Commercial software (ANSYS 16.2 - FLUENT) is used to predict 2-D pollutant emission with GRI 3.0 detailed reaction mechanism. In addition, the addition of hydrogen to LCG 6000 was also considered. As result, the flame length and temperature of LHVGs were decreased with decreasing calorific value at the same condition. In addition, NO concentration was decreased as temperature decreased. However, CO concentration for LCG 8000 predicted to be slightly higher than that for methane due to the high propane concentration. In the case of LCG 6000 with added hydrogen, the flame length was the shortest and NO concentration was the highest due to the highest flame temperature, but CO concentration decreased rapidly due to the addition of the carbon-free fuel.

In this study, the combustion characteristics of low calorific gas (LCG) fuels are investigated by numerical simulation. PREMIXED code is used to predict the flame structure and NO emission with two mechanisms, which are GRI 3.0 and USC II chemical reaction mechanisms for CH4 and LCG 8000 and LCG 6000, respectively. Also, elementary reactions related with production and destruction for OH radical are studied because OH radical is dominant for burning velocity and NO emission. As results, the production and the destruction of OH radical for CH4 and LCG 8000 using GRI 3.0 are dominated by reactions of No. 4, No. 2 and No. 3 and by No. 5, No. 3 and No. 7, respectively. For LCG 6000 using USC II, reactions of No. 3, No. 4 and No. 11 and of No. 7, No. 8 and No. 12 dominates to the production and the destruction, respectively. In addition, NO emissions for LCG gas fuel are generated by thermal NO because the flame temperatures are over 1800 K.