Combustion of blends of Kangal lignite and hazelnut shells in a fixed bed

It is clear that coal will be an effective fuel in electricity generation today and in the future. However, apart from sulphur oxides and nitrogen oxides which cause air pollution during coal combustion, greenhouse gas emissions (such as CO2, CH4) are also important problems. The cost effective method in decreasing these gases which cause air pollution is combustion of coal together with biomass. Decreasing these gases due to air pollution, biomass can be an alternative fuel considering its potential in regard of coal reserves. Since there are a lot of low value lignite reserves in our country, using these coals in combustion systems decrease energy generation efficiency and causes air pollution. Considering biomass potential of Turkey as an agricultural country, combustion of low value lignite together with biomass is necessary for preventing air pollution and protecting lignite reserves. For commercial design of combustion systems, it is important to analyze combustion behaviours of coal-biomass blends and flue gas emissions. In this study combustion of Kangal lignite together with hazelnut shell in fixed bed combustion system was analyzed. The effect of temperature and biomass on fixed bed combustion was analyzed when a specific amount of biomass is included in lignite. In co-combustion experiments, combustion times and rates of volatiles and carbon were determined. At the same time, carbon dioxide, sulphur dioxide and nitrogen oxide emissions were also measured during combustion. It was observed that flame times of raw fuels (100% lignite and 100% biomass) and blends (including 25%, 50% and 75% biomass) decreased with temperature. It was observed that ignition times of blends decreased depending on the biomass ratio. It was concluded that there was no relation between volatiles combustion times and combustion rate of raw fuel and blends and these two fuels have effected each other in volatiles evolusion period. It was observed that carbon combustion times of raw fuels and blends decreased with temperature, carbon combustion rates increased with temperature, and carbon combustion rate of blends were higher than raw fuels. Depending on the increase of in lignite ratio in the blend, it was determined that unburned carbon amount is high. It was observed that SO2 emissions were higher than biomass during combustion of single raw lignite, and this decreased due to when it is burned together with biomass. It was determined that CO2 emissions were high in raw biomass and in blends during combustion. It was observed that NO emissions were higher in biomass and blend compared to raw fuel due to structural differences of biomass and lignite.