Combustion characteristics of municipal sewage sludge with different initial moisture contents

The combustion characteristics of municipal sewage sludge samples with five different initial water contents (5.02, 8.21, 17.33, 27.45 and 37.85%) were assessed by using a thermogravimetric analysis approach. The ignition temperatures of the samples increased with increasing the heating rates and their initial moisture content. Ignition, burnout and comprehensive performance indices of the samples increased with decreasing their initial moisture contents. Between heating rates of 20 and 80 K min(-1), the average ignition, burnout and comprehensive performance indices of the sample with initial moisture content of 5.02% were about 1.2, 2.2 and 0.9 times more than those of the sample with initial moisture content of 37.85%. The average activation energies for the samples with 5.02, 8.21, 17.33, 27.45 and 37.85% moisture contents were 146.59, 148.02, 155.13, 156.70 and 168.39 kJ mol(-1). There were certain linear relations among two main kinetic parameters for the samples with different moisture contents and their main combustion stages.