Energetic and economic analysis of ethanol, xylitol and lignin production using oil palm empty fruit bunches from a Brazilian factory

Abstract

The oil palm empty fruit bunches (OPEFB) are the largest solid residues generated in the oil palm processing. At present, OPEFB is considered one of the most important lignocellulosic materials for producing chemicals and fuels, however, because of their recalcitrance, there are necessary pretreatment steps for solubilization of monomeric sugars. Three pretreatment configurations, sequential acid/alkaline, steam explosion with alkaline delignification and steam explosion without delignification, for co-production of ethanol, xylitol, and lignin using OPEFB as feedstock were analyzed. The pretreatment performance was analyzed as a function of the yearly total profit and the net energy value (NEV). Sensibility analysis was carried out taking into consideration 7 cases by varying the price of ethanol, xylitol, and lignin in accordance with commercial price and data reported in the literature. The results showed that sequential steam explosion followed by alkaline delignification, presented the largest yearly profit for all the cases analyzed, followed by acid/alkaline treatment. The positive economic profit was attributed to the production of xylitol and lignin. While the steam explosion presented negative yearly profit, this pretreatment presented the highest energy positive NEV of 9.9 MJ∙kg-1 OPEFB treated. These results showed that the use of OPEFB as a potential feedstock for biorefinery process could be feasible if all the fractions obtained in pretreatment stages are valorized. © 2018