Investigation on Interaction of Combustion Parameters of Coal-Water Mixtures Used in Fluidized Bed Combustor

Abstract

Three different Turkish Lignites (İstanbul-Yeniköy, Manisa-Soma, and Muğla-Milas) were prepared in accordance with coal-water mixtures technology to determine the combustion parameters of a laboratory-scale fluidized bed combustor. In this context, the effects of parameters such as Ca/S, mean bed temperature, preheat, air emission, and feed rate were investigated on SO2, NOx, and CO emissions, while the combustion efficiency and the amount of unburned C were also calculated. In the combustion tests, it was observed that the quantity of SO2 in the flue gas is reduced when there is an increase in the Ca/S ratio in the mixtures. A maximum 95% of sulfur can be removed with Ca/S:4. It was observed that when the temperature in the fluidized bed unit increases, NOx emission increases and CO emission decreases. The optimum bed temperature was found to be approximately 900°C. The preheat temperature of the mixture significantly affects combustion and the efficiency is advanced by increasing preheat temperature. It was also determined that the amount of air added to the combustor affects the efficiency of combustion, with larger quantities of air resulting in lower amounts of unburned C in fly ash; however, increases in air quantities result in higher emissions of NOx.