<p>In recent large-scale pulverized coal-fired power plants, the co-firing of biomass fuels is being promoted to reduce carbon dioxide emissions per unit of power generation. One of the issues related to the biomass co-firing is the deposition and agglomeration of trace components in the boiler. In this study, we focused on silicon compounds as trace components that affect the combustion process. Silicon compounds are simultaneously combusted with biomass fuels, leading to the formation of silica particles, which can adhere to combustion boilers and cause performance deterioration, as well as contribute to atmospheric pollution as particles smaller than PM2.5. Therefore, countermeasures are necessary. The aim of this study is to investigate the combustion characteristics of organic silicon compounds and the behavior of silica particle formation within a pulverized coal combustion boiler. Siloxane, which is might be considered as one of the trace components in biomass, is used as a substitute for silicon compounds, and combustion experiments are conducted using a Drop Tube Furnace (DTF). The analysis of the generated particles provides insights into the formation behavior of silica particles under combustion conditions. When siloxane was combusted using the DTF (Drop Tube Furnace) apparatus, it resulted in the formation of primary particles consisting of white silica particles with amorphous structures at the nanoscale or below.</p>