The potassium release from sawdust in pyrolysis and gasification was studied using an online measurement method. The final results suggested that the potassium releases more in pyrolysis than that in CO2 gasification environment at 800-900 degrees C. The overall activation energies and pre-exponential factors of potassium release in pyrolysis and gasification were further derived. In addition, the additive chlorine influence on potassium release had been evaluated, and the results showed that the promoting effect of chlorine during pyrolysis was higher than the case during CO2 gasification. Thermodynamic calculations were done to predict the possible potassium species during pyrolysis and gasification. The K2CO3 (s) formation mostly contributed to the higher potassium release proportion in pyrolysis than that during CO2 gasification. (C) 2020 Elsevier Ltd. All rights reserved.