Thermal analysis and products distribution of dried sewage sludge pyrolysis

• Pyrolysis behavior of dried sewage sludge was investigated by thermogravimetric analysis and a tubular pyrolyzer.
• The activation energies for two temperature ranges of 186–296 °C and 296–518 °C were 82.28 kJ mol−1 and 48.34 kJ mol−1, respectively.
• The main gaseous products identified by the FTIR were CH4, CO2, CO and organic volatile compounds such as aldehydes, acids, alcohols and phenols.
• The maximum oil yield of 46.14% was obtained at the temperature of 550 °C under the fast pyrolysis condition.

Pyrolysis behavior of dried sewage sludge was studied by thermogravimetric–Fourier transforms infrared analysis (TG–FTIR) and differential scanning calorimetry (DSC) to investigate thermal decomposition and kinetics analysis. A tubular pyrolyzer was used to explore the production distribution of dried sewage sludge pyrolysis under different runs. The results showed that two weight loss peaks were presented in pyrolysis reaction in the ranges of 186–296 °C and 296–518 °C, and the activation energy of each stage was 82.284 kJ mol−1 and 48.342 kJ mol−1, respectively. The main gases identified by FTIR analysis were CH4, CO2, CO and organic volatile compounds such as aldehydes, acids, alcohols and phenols. Under fast pyrolysis of dried sewage sludge, the maximum tar yield obtained was 46.14% at the temperature of 550 °C. The concentrations of all gases increased steadily with increasing pyrolysis temperature from 450 °C to 650 °C except for CO2.