Investigation of additivation effect on combustion of biofuel derived from poultry waste and pine woodchips

The aim of this thesis is to add value to animal waste and forestry waste by converting them into green energy. Within the scope of the thesis, various additives were added to reduce operational problems and to obtain low particulate matter (PM) and flue gas emissions during the combustion of poultry waste and pine woodchips in equal proportions by weight in air and oxy-fuel combustion conditions. It is important to determine the appropriate additive for the fuel mixture, especially to reduce PM emissions. Therefore, in the first stage of the study, a fast screening method based on thermogravimetric analysis (TGA) in oxygen environment was used to determine the effectiveness of different additives (CaHPO4, MgCO3, MnCO3, MgPO4, Kaolin, CaO, Zn) on the biomass mixture. The most suitable additives for the fuel mixture were determined as Zn and MgCO3, and the thermal degradation performances of biofuels containing 2 wt. % additives were examined by TGA method in nitrogen environment, air environment and oxy-fuel combustion conditions. Ashes obtained from the addivated biofuel mixture were examined by XRF, XRD, SEM-EDS analyses, and the effect of additives on the ash structure was determined. Flue gas emissions of Zn and MgCO3 additives, which provide low PM emissions when burning the biofuel mixture, were analyzed by TGA-FTIR under combustion and oxy-fuel combustion conditions. It has been observed that the highest emission is CO2, and the oxy-fuel combustion process and addivation have a reducing effect on CO2 emissions. Under oxy-fuel combustion conditions, higher CO, lower NOx, SO2 and HCl emissions occurred at a lower rate compared to the air environment, and additives also showed a reducing effect. The composition and crystal structure of Zn addivated biofuel ash support its reducing effect in PM emissions. It was concluded that Zn is a more suitable additive in terms of PM and flue gas emissions than MgCO3. Keywords: poultry waste, pine woodchips, co-combustion, additive, renewable energy, waste management