Enhancement of the Biofuel Characteristics of Empty Fruit Bunches through Hydrothermal Carbonization by Decreasing the Inorganic Matters

Abstract

This study explores the effects of hydrothermal carbonization (HTC) on the fuel properties of empty fruit bunches (EFB) by varying the reaction temperatures between the range of 180–300 °C. The improved properties of hydrochars following HTC were achieved by analyzing the changes in the physical and chemical properties of EFB. Moreover, it can save energy during treatment processes, in addition to evaluating the improvement of the biofuel stability based on the equilibrium moisture content and agglomeration. The results showed that the chemical structure of EFB decomposed owing to dehydration and decarboxylation reactions, leading to increased carbon and fixed carbon concentrations in the obtained hydrochar; and thus, an increased calorific value. Hydrochar generated during HTC exhibited chemical properties similar to those of conventional coal fuel. The optimal HTC reaction temperature range was ~230–250 °C. Based on the X-ray fluorescence results, hydrochar produced during HTC had smaller K and Cl contents and a smaller degree of agglomeration than the original sample, indicating that clinker production can be reduced by the HTC of EFB. The results of this study have significance in the utilization of unused waste biomass as an energy source that can replace fossil fuels.