Burning characteristics and the fuel properties of the dry-carbonization chars of sewage sludge

As an alternative treatment to hydrothermal carbonization, sewage sludge (SS) was subjected to dry carbonization at temperatures of 200-700 °C to produce pyrochar. The fuel properties of the obtained chars were characterized, and their combustibility was checked by thermal analysis method. The combustibility of the chars was evaluated considering the criteria such as the ignition index (C_i), burnout index (C_b), comprehensive combustibility index (S), and the burning stability index (D_W). Although even low temperature treatments such as 200 °C and 300 °C did not improve the calorific value, some improvements took place in the combustion characteristics upon treatment.