Supercritical water gasification of real biomass feedstocks in continuous flow system

In this study, supercritical water gasification of the selected five biomass samples (cauliflower residue, acorn, tomatoes residue, extracted acorn and hazelnut shell) was investigated. Lignocellulosic feedstocks were gasified in a continuous flow reactor at 600 °C and 35 MPa. The product gas is composed of hydrogen, carbon dioxide, methane, carbon monoxide and a small amount of C2 compounds. Quantitative analysis of product gas was performed by Gas chromatography device. Potassium carbonate (K2CO3) and Trona (Na2CO3·NaHCO3·2H2O) were used as catalysts. Carbon gasification efficiencies were improved by addition of these catalysts into the reacting system. Moreover, carbon gasification efficiency changes with type of biomass that includes different ratio of cellulose, hemicellulose and lignin. The H2 yield (mol gas/kg C in feed) of acorn in the presence of Trona was found to be 7 times higher than that of without catalyst.

► We examine effects of alkali catalysts on supercritical gasification of biomasses.
► We studied with biomass samples having different amount of cellulose, lignin and hemicellulose.
► Alkali salts increase the H2 and CO2 yields and decrease the CO yield.
► Trona was found to be as effective as K2CO3 in SCWG of biomass feedstock.