Gasification of sugarcane bagasse in supercritical water; evaluation of alkali catalysts for maximum hydrogen production

Abstract

Sugarcane bagasse is one of the major resources of agricultural wastes in the Khuzestan Province of Iran. With the aim of maximum hydrogen production, supercritical water gasification of lignocellulosic feedstock was studied in a batch reactor at the constant pressure of 25 MPa. The effect of catalyst (five different alkali salts, Raney nickel, and activated carbon) and reaction temperature (400–800 °C) on gas yield and composition, gas heating value, carbon gasification efficiency (CGE), and hydrogen gasification efficiency (HGE) was investigated. An increase in reaction temperature led to significant improvement in hydrogen yield. The highest amount of hydrogen (75.6 mol kg−1) was achieved at 800 °C with the presence of KOH as catalyst where the complete gasification of bagasse took place. The annual potential of hydrogen production in the Khuzestan Province of Iran was roughly estimated to be 470 millions of Nm3 and this calculation showed that this figure is capable of substituting the need of 6550 ha of sugarcane farms to chemical fertilizer.