Thermal conversion behavior of paper mill sludge: characterization, kinetic, and thermodynamic analyses

The present paper reports the pyrolysis behavior, kinetic, and thermodynamic parameters of paper mill sludge (PMS), which is a paper manufacturing residue and cannot be re-evaluated, at three heating rates (5, 10, and 20 degrees C min(-1)) under non-isothermal conditions. Ultimate and proximate analyses of the paper mill sludge were carried out. Kinetic and thermodynamic parameters were calculated using four model-free methods; Flynn-Wall Ozawa (FWO), Friedman, Kissinger-Akahira-Sunose (KAS), and distributed activation energy model (DAEM). High R-2 values revealed that all models are compatible with TGA data. The activation energy calculated (101.01 kJ mol(-1)) from FWO was higher than the other three methods. Pre-exponential factor values ranged from 0.56 x 10(3) and 14.55 x 10(3) s(-1) for all methods. Kinetic and thermodynamic findings will be beneficial in terms of the process design of PMS pyrolysis.

Automated summary

This study reports the pyrolysis behavior, kinetic, and thermodynamic parameters of paper mill sludge (PMS) under non-isothermal conditions. The findings of the kinetic and thermodynamic analyses provide valuable insights for the process design of PMS pyrolysis.