In recent years, many countries have invested enormous efforts to tackle increasingly harsh environmental problems, especially the greenhouse effect. The addition of biomass into coal is regarded as a promising technology to mitigate CO2 emissions. However, the costs related to retrofitting injection systems and unstable combustion inhibit this option. Therefore, this thesis developed a two-in-one fuel that impregnates molasses into the holes of low-rank coal(LRC), which can be directly applied to existing boilers. However, due to the existence of alkali and alkaline earth metals(AAEMs) in molasses, the impregnation of molasses into the coal pores possibly lead to the ash deposited on the surface of the heat exchanger, thus reducing the heat exchange efficiency. Besides, a part of fine particles will emit into the atmosphere, resulting in a series of air pollutions. Thus, the investigation of ash deposition and fine particle formation is a significant topic to promote heat exchanger efficiency and protect the environment. In this study, three fuels, Berau coal, Berau coal impregnate with 10wt% and 20wt% molasses were selected. Experiments are carried out in drop tube furnace (DTF) under the combustion temperature of 1300°C and the ash probe temperature of 800°C with access air. The fuel is fed at a rate of 0.45g/min for 10min. The properties of the ash depositions are analyzed.