Combustion of a high ash and sulfur containing lignite in a pilot circulating fluidized bed combustor and its pollution characteristics

In this study a 50 kW circulating fluidized bed combustor (low velocity reg ime CBF combustor) was constructed for the combustion of high ash containin g lignites. Beypazary lignite which contains 45% ash and 3.72% sulfur was m ixed with limestone and was burnt in this combustor. Emission characteristi cs were investigated at different Ca/S mole ratios. It was shown that SO, r emoval efficiencies reached values of 98%. At an average bed temperature of 850 degrees NOx emission levels were found to be around 300 ppm however CO emissions were around 1466 ppm. Temperature variation along the combustor (of 1.8 m in height) was found to be about 140 and 90 degreesC for two diff erent feed points located at 0.17 and 0.52 m above the distributor and two different feedback points located at 0.37 and 0.17 ra above the distributor , respectively. (C) 2002 Elsevier Science B.V. All rights reserved.