Thermogravimetric study and kinetic analysis of dried industrial sludge pyrolysis

•The non-isothermal thermogravimetric method was employed to investigate the industrial sludge pyrolysis behaviors.•The distribution activation energy model (DAEM) was proposed to study the kinetics of devolatilization process.•The FTIR method was used to determine the relationship between the sludge structure and pyrolysis behaviors. Thermogravimetric experiments of two different industrial sludge samples were carried out with non-isothermal temperature programs. The results indicated that the pyrolysis process contains three obvious stages and the main decomposition reaction occurred in the range of 200–600°C. The distributed activation energy model (DAEM) was also proposed describing equally well the pyrolysis behavior of the samples. The calculated activation energy was ranged from 170 to 593kJ/mol and 125 to 756kJ/mol for SLYG (sludge sample from chemical fiber factory) and SQD (sludge sample from woody industry), respectively. The reliability of this model not only provided good fit for all experiments, but also allowed accurate extrapolations to relative higher heating rates. Besides, the FTIR measurement was also used to further understand the relationship between pyrolysis behavior and chemical structures for industrial sludge.