Biomass as a renewable fuel is considered to be CO2 neutral. However, firing biomass in power generation plant, either as a sole fuel or for co-firing in both air and oxy-firing conditions, causes a number of complications, such as slagging, fouling, and increased depositions and corrosion on the superheat-exchange tubes. This would reduce both system efficiency and durability. An advanced Computational Fluid Dynamics model will be developed in order to simulate the formation of aerosol, and the process of deposition of fine particles on combustion chamber and heat exchange tube surfaces, that occur during biomass combustion. The model development will be based on an existing model that has previously been developed at Leeds and will be validated against measurement data. The successful outcome of this research will be very useful for biomass fuel selection and combustion system optimization for power generation plant co-firing biomass and coal.