5.2.2.1 Empty Fruit Bunches

EFB is a nonwood lignocellulosic material which forms about 23% of the total mass (or weight) of the FFB (Schmidt 2007). EFBs are the wastes (i. e. solid residue pro­duced in largest quantity in the oil mill) obtained after stripping off the fresh palm fruitlets from the whole FFB. An EFB is made up of a main stalk (about 20-25% of the total weight of EFB) and numerous spikelets (about 75-80% of the total weight of the EFB) with sharp spines at their tips (Ahmad et al. 2009). The production of 1 tonne of CPO generates nearly 1.3 tonnes of EFB. Globally, about 42.3 million tonnes of EFB is generated by the palm oil industry annually (Kelly-Yong et al. 2007; Ahmad et al. 2009).

EFB vascular strands contain about 41.3-46.5% cellulose, 25.3-33.8% hemicel — lulose and 27.6-32.5% lignin (Sudiyani 2009; Piarpuzan et al. 2011). EFB sugar contents are about 2.5% galactose and 33.1% glucose (Abdul Khalil et al. 2006). Current research on the proximate and ultimate analysis of EFB by Mohammed et al. (2012) shows about 55.6% moisture content (by wet weight), 3.45% ash, 8.97% fixed carbon, 82.58% volatile matter, 46.62% carbon, 6.45% hydrogen, 1.21% nitrogen, 0.035% sulphur, 0.18% magnesium, 0.06% phosphorus and 45.66% oxygen in the EFB (Elbersen et al. 2005). The fatty acid content in EFB is <2% with its extractives and crude protein also constituting approximately 7.8% and 1-3.8%, respectively. Though the calorific value of EFB is between 17 and 19 MJ/kg (Ma and Yusoff 2005; Mohammed et al. 2012), a value slightly lower (due to high moisture and oxygen contents) than that for wood and coal (Demirbas 2004; Yang et al. 2006), it serves as a potential source of biofuel.

The inorganic contents (expressed in % ash, moisture free) of EFB have been analysed by Lahijani and Zainal (2011) , Omar et al. (2011) and Mohammed et al. (2012) to consist of Si2O (10.83-27.0), K2O (34.7-53.73), CaO (1.9-12.5), MgO (4.8-8.75), Cl (3.6-5.3), Fe2O3 (1.28-3.6), Al2O3 (0.46-1.22), Na2O (0.55­1.54) and P2O5 (1.12-3.6). EFB fuel density is about 1,420 kg/m3 (Mohammed et al. 2012).