This study investigated the effect of crude Jatropha oil (CJO) blending with C-heavy oil on the combustion characteristics of oil-fired boilers. Combustion experiments were conducted using a 550 kW liquid fuel combustion test facility equipped with a steam-atomizing burner. The results indicated that the flame radiation intensity is decreased by the CJO blending with C-heavy oil. Consequently, the heat absorption of the sections near the burner decreases. Due to the lower nitrogen and sulfur contents in CJO, the NOx and 502 emissions are decreased by the CJO blending with C-heavy oil. It was also found that both the particulate matter concentration and the particle size in the exhaust gas are decreased by the CJO blending. This is attributed by the low carbon residue content of CJO. The results of this study imply that when CJO is introduced into oil-fired thermal power stations, considerable attention should be paid to changes in the heat absorption balance and the possibility of a decrease in the particle collection efficiency of the electrostatic precipitator. (C) 2018 Elsevier Ltd. All rights reserved.