Supercritical water gasification of fructose as a model compound for waste fruits and vegetables

Generous amount of waste food as refused fruits and vegetables are obtained on a global scale that is usually disposed in landfill or oceans. The waste fruits are enriched with fructose, glucose and sucrose along with minor amounts of cellulose and hemicellulose that could potentially be converted to biofuels and biochemicals. With this objective, fructose was used as a model compound of waste fruits and vegetables for gasification in supercritical water using a continuous flow tubular reactor. Different parameters influencing supercritical water gasification were investigated in this study such as temperature (550-700 degrees C), residence time (30-75 s), feed concentration (4-10 wt%) and catalyst concentration (0.2-0.8 wt%) at a constant pressure of 25 MPa. Total gas yields, carbon gasification efficiency and hydrogen yields improved at an optimal temperature (700 degrees C), feed concentration (4 wt%) and residence time (60 s). Fructose gasification with 0.8 wt% KOH enhanced the selectivity for hydrogen (10.67 mol/mol) compared to those by 0.8 wt% NaOH (9.86 mol/mol) and non-catalytic gasification (3.37 mol/mol). (C) 2015 Elsevier B.V. All rights reserved.