The Effects of Exhaust Gas Recirculation on Premixed Type Condensing Boiler

초록

The premixed combustion system as the preheated air condensing boiler applying exhaust gas recirculation (EGR) was investigated to achieve the low pollutant emission and the high thermal efficiency. In this study, it was studied the effects of EGR on the thermal efficiency, NOx and CO emissions with various EGR and equivalence ratios, numerically and experimentally. As results, when the equivalence ratio increased, thermal efficiency and NOx and CO concentrations increased. Especially, in the case of 15% of EGR ratio at 0.85 of equivalence ratio, NOx and CO concentrations were a smaller than these of the current operating condition of the boiler (𝜑=0.78) and the thermal efficiency was approximately 1.7% higher.