Vol.:(0123456789) Reaction Kinetics, Mechanisms and Catalysis https://doi.org/10.1007/s11144-019-01659-w 1 3 Torrefaction of Leucaena Leucocephala under isothermal conditions using the Coats–Redfern method: kinetics and surface morphological analysis Aznie Nadiera Awang 1  · Alina Rahayu Mohamed 1  · Noor Hasyierah Mohd Salleh 1  · Peng Yong Hoo 1  · Nur Nasulhah Kasim 2 Received: 4 March 2019 / Accepted: 25 August 2019 © Akadémiai Kiadó, Budapest, Hungary 2019 Abstract The efects of temperature and holding times on the torrefaction of Leucaena Leuco- cephala (Leucaena) were elucidated via a novel isothermal decomposition approach. The torrefaction was performed in a fxed-bed reactor at temperature ranged from 200 to 300 °C for 20, 40 and 60 min. The efects of both torrefaction temperature and holding time were studied quantitatively and qualitatively by evaluating the dis- tribution product yields and surface morphological changes. Quantitatively, the mass yield decreased with increasing temperature for all tested holding times, while the liquid and gas yields increased steadily due to the release of volatiles from the bio- mass decomposition. Qualitatively, signifcant morphological changes on Leucaena due to torrefaction were evidently captured via SEM imaging analysis. For torrefac- tion temperatures from 200 to 260 °C, the raw and torrefed Leucaena showed that pore evolution process had become evident. However, for torrefaction temperatures from 280 to 300 °C, the torrefed Leucaena revealed that the internal structure of torrefed Leucaena underwent pore development process. The pore development was noticeably observed for all temperatures. The values of activation energy (E a ) and pre-exponential factor (ln A) for the torrefaction were calculated based on the Coats–Redfern method for frst order reaction. The values of E a and ln A for 20, 40 and 60 min were found to be 39.75, 40.10 and 42.31 kJ/mol, and 3.92, 4.14 and 4.67. As a conclusion, the torrefaction of Leucaena from 200 to 300 °C for 20 min holding time is more reactive as compared to that at higher holding time. Keywords Leucaena · Single heating rate · Isothermal · Kinetics · Torrefaction Electronic supplementary material The online version of this article (https://doi.org/10.1007/s1114 4-019-01659-w) contains supplementary material, which is available to authorized users. * Alina Rahayu Mohamed alinamohamed@rocketmail.com Extended author information available on the last page of the article