The aim of this work was to study the characteristics of solid and liquid products from the torrefaction of oil palm fiber pellets (OPFP) in inert and oxidative environments. The torrefaction temperature and O-2 concentration in the carrier gas were in the ranges of 275-350 degrees C and 0-10 vol%, respectively, while the torrefaction duration was 30 min. The oxidative torrefaction of OPFP at 275 degrees C drastically intensified the HHV of the biomass when compared to the non-oxidative torrefaction. OPFP torrefied at 300 degrees C is recommended to upgrade the biomass, irrespective of the atmosphere. The HHV of condensed liquid was between 10.1 and 13.2 MJ kg (1), and was promoted to 23.2-28.7 MJ kg (1) following dewatering. This accounts for 92-139% improvement in the calorific value of the liquid. This reveals that the recovery of condensed liquid with dewatering is able to enhance the energy efficiency of a torrefaction system. (C) 2015 Elsevier Ltd. All rights reserved.