AbstractThis investigation reports a kinetic and thermodynamic study (using the Kissinger–Akahira–Sunose method) of coal–sawdust co‐pyrolysis calculated beyond the evaporation zone. The effects of co‐pyrolysis on activation energy (E a) and thermodynamic parameters are compared with those of individual pyrolysis. This study clarifies the effect of biomass on the thermal stability of coal during co‐pyrolysis. The co‐pyrolysis of sawdust with coal helps increase the rate of thermal degradation in the low‐temperature degradation zone by reducing the activation energy and Gibbs free energy. The alternation of the value of E a from positive to negative occurs beyond the active pyrolytic zone. The overall E a of coal pyrolysis (196 kJ mol−1) shows a value higher than that for the co‐pyrolysis of coal and sawdust (100.632 kJ mol−1). Similarly, the Gibbs free energy and enthalpy for coal also show higher values associated with co‐pyrolysis. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd