Removal of sulphur during combustion of coal by using lime

Abstract

Environmental pollution has become one of the main problems of the world. Air pollution is considered to be one of the main components of this problem. Sulphur dioxide (SO2) that usually emits into air out of burning of fossil fuels is the most important air pollutant. Filtering the emission of SO2 is generally accepted as the most effective method for preventing air pollution. In this study, an alternative technique was applied to coal with high sulphur content in order to prevent the emission of SO2. Main principle of the method is based on adding a calcinated limestone (CaO) to the coal during combustion. The experiments were carried out with Can coal mined from the north-west of Turkey. The coal was broken into small particles of <710 mu m in diameter. Two different limestone samples (labeled as LS1 and LS2) with the size of <700 mu m in diameter were calcinated at 900-950 degrees C for 180 min. Then, 0.25, 0.50, 0.75, 1.00 and 1.50 g of calcinated limestone samples were well mixed with 5 g of coal. Combustion processes were performed in a fixed batch oven at 850 and 900 degrees C for 120 and 180 min. It was found that desulphurization of coal strongly depends on the amount of added limestone and its size, combustion time and temperature.