A strictly isoconversional rate expression has been derived for pyrolysis of biomass. This rate expression, derived from non-isothermal thermogravimetric experiments using heating rates 2-10 K/min, can successfully predict the conversion rates of experimental data at heating rates 1-100 K/min and quasiisothermal experiments at 539-650 K. The methodology used is based on an extension of the incremental integral method by Vyazovkin (2001). Being able to derive an intrinsic reaction rate expression from non-isothermal data, without any assumption regarding the chemical processes present, opens up for the possibility to model industrial pyrolysis reactors, with a variety of temperature profiles.
Páscoa Dos Santos Magaia is gratefully acknowledged for developing and performing the proximate analysis on spruce. The authors would also like to thank Elisabet Brännvall and Daniel Tavast for providing the milled spruce and performing the wet analysis characterization on this sample. This work was carried out within the Swedish Gasification Centre consortium. Funding from the Swedish Energy Agency and the academic and industrial partners is gratefully acknowledged. Rosana Moriana acknowledges financial support by the Wallenberg and Lars-Erik Thunholm Foundation. Finally the authors would like to thank the reviewers of this work for their constructive comments.