Isothermal combustion kinetics of synthetic refuse plastic fuel (RPF) blends by thermogravimetric analysis

Thermal behavior of wastewater sludge, plastic and synthetic blends during combustion process was studied to identify potential of refused derived fuel application. Experiments were conducted in a large-scale thermogravimetric analyzer at temperatures ranging from 400 °C to 700 °C in the presence of air flow at 8 L/min. Isothermal modeling was performed to find system kinetic parameters including combustion reaction rate constant (k), order of reaction (n), Arrhenius pre-exponential factor (A) and activation energy (E). Results revealed that with increase in temperature from 400 °C to 700 °C, maximum rate of combustion was observed to increase from 1.6%/min to 7.12%/min and 2.09%/min to 21.9%/min for wastewater sludge and plastics, respectively. The corresponding time for maximum weight loss rate was observed to decrease from 15 min to 3.1 min for wastewater sludge and from 47 min to 3.8 min for plastic. Thermogravimetric profile and activation energy indicated that refuse plastic fuel blends with higher percentage of plastic required higher activation energy than wastewater sludge from 12.43 kJ/mol to 58.60 kJ/mol. Experimental results show the potential to explain and predict combustion behavior and activation energy of combustion of wastewater sludge and plastic blends in practical RPF applications.