Hydrothermal Treatment of Empty Fruit Bunch (EFB) Aimed at Increased Production of Reducing Sugars

The waste generated from the palm oil production chain is increasing. The purpose of this work is to enable more effective use of empty fruit bunches (EFB) to produce reducing sugars by a hydrothermal treatment process (hydrothermolysis) at elevated pressures and temperatures. The EFB was dried and milled to obtain three different granulometries: thin (> 60 mesh), medium (28 to 60 mesh), and thick (< 28 mesh). The operating conditions were defined using a complete factorial design of 25, while considering the variables as particle size (thin, medium, and thick), solid/liquid ratio (1/13.33 and 1/20), temperature (130 and 170 oC), reactor pressure using CO2 (150 bar and 200 bar), and reaction time (10 and 20 min). The reactional system converted the EFB into 17.5% and 57.9% of reducing sugars, for thin and medium samples, respectively, which were performed under the same conditions. The statistical analysis indicated that the main effects for hydrothermal treatment are time and temperature.