Torrefaction of oil palm mesocarp fiber and their effect on pelletizing Byeong-Ill Na a , Young-Hun Kim a , Woo-Seok Lim a , Soo-Min Lee b , Hyoung-Woo Lee a , Jae-Won Lee a,c, * a Department of Forest Products and Technology, College of Agriculture & Life Sciences, Chonnam National University, Gwang-ju 500-757, Republic of Korea b Division of Wood Chemistry & Microbiology, Department of Forest Products, Korea Forest Research Institute, Seoul 130-712, Republic of Korea c Bioenergy Research Center, Chonnam National University, Gwangju 500-757, Republic of Korea article info Article history: Received 24 December 2012 Received in revised form 19 February 2013 Accepted 26 February 2013 Available online 1 April 2013 Keywords: Torrefaction Response surface methodology Severity factor (SF) Calorific value Energy yield Torrefied pellet abstract The optimal condition for the torrefaction of oil palm mesocarp fiber was investigated by response surface methodology. Pelletizing properties of torrefied biomass were analyzed depending on torrefaction conditions. The elemental composition of torrefied biomass was influenced by the Severity Factor (SF) of torrefaction. The carbon content in the torrefied biomass increased from 48.02 to 54.83%, while the hydrogen and oxygen contents decreased with the SF. The calorific value of torrefied biomass ranged from 19.15 to 22.82 MJ kg 1 . This implied that the energy contained in the torrefied biomass increased by 5e19%, when compared with untreated biomass. The calorific value and weight loss in the biomass increased as the SF increased. The energy yield was high at a low SF, allowing for weight loss and calorific value. At a high SF, no pellets were made by torrefied biomass, or many defects were shown in the torrefied pellet, while the pellets were produced with good formation at a low SF. Crown Copyright ª 2013 Published by Elsevier Ltd. All rights reserved. 1. Introduction Lignocellulosic biomass residues plays a major role in the production of sustainable energy, because it is abundant, relatively inexpensive, and often locally available. In recent years, growing attention worldwide has focused on the use of lignocellulosic biomass residues as a feedstock to produce biofuel pellet, as an alternative to fossil fuel [1,2]. Malaysia is the largest exporter of palm oil in the interna- tional market. In the process of extraction of palm oil from palm fruit, a mesocarp fiber is generated as a residue, which is ob- tained at the nut and fiber separator. In practice this mesocarp fiber is burned in incinerators by palm oil mills, which not only creates environmental pollution problems in nearby localities, but also offers limited value to the industry [3]. The annual amount of mesocarp fiber generated by the oil palm industry is 10.3 million tonne [4]. Therefore, availability of mesocarp fiber is considered to be the best among biomass residues [5]. The torrefaction process has been used for high energy density of lignocellulosic biomass. Torrefaction is a thermal * Corresponding author. Department of Forest Products and Technology, College of Agriculture & Life Sciences, Chonnam National University, 77 Yongbong-ro Buk-gu, Gwang-ju 500-757, Republic of Korea. Tel.: þ82 625302098; fax: þ82 625302099. E-mail address: ljw43376@chonnam.ac.kr (J.-W. Lee). Available online at www.sciencedirect.com http://www.elsevier.com/locate/biombioe biomass and bioenergy 52 (2013) 159 e165 0961-9534/$ e see front matter Crown Copyright ª 2013 Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.biombioe.2013.02.041