(783d) Interaction Between Model Compounds in Lignocellulosic Biomass Under Supercritical Water Conditions

Supercritical water gasification (SCWG) is a conversion technique to transform biomass into energy without necessity of drying process because water in supercritical state (temperature and pressure above 374 °C and 22.1 MPa, respectively) behaves as an organic solvent so that a high conversion can be achieved. Plant biomass or lignocellulosic biomass is a good candidate for a feedstock utilized in this process due to its large availability on Earth. It consists of cellulose, hemicellulose, which are easy to be gasified and lignin, which inhibits gasification. Previously, reaction pathways of cellulose, hemicellulose and lignin were individually proposed by many researchers. However, the study of the reaction mechanisms of the overall biomass is still rare. Therefore, this research is to study the interaction between these compounds in supercritical water aiming for better understanding in a behavior of lignocellulosic biomass in the gasification. To simplify the reaction mechanisms, model compounds for each component are employed instead of the complex structure of those. The interaction between glucose that is a model compound of cellulose, xylose that is a model compound of hemicellulose and guaiacol that is a model compound of lignin is investigated using tubular reactor system composed of high-pressure pumps, a preheater, a reactor made of stainless steel SS316 with inner and outer diameters of 1 mm and 1.59 mm (1/16 inch), respectively, heat exchangers, a back-pressure regulator, and a gas- and liquid-sampling system. Molten salt is used as heating medium for heating pre-heated water and the reactor. Mixture solutions of glucose, xylose and guaiacol were prepared in designated concentrations: 0.3 % wt.: 0.0 % wt.: 0.1% wt., 0.2 % wt.: 0.2 % wt.: 0.0 % wt., 0.0 % wt.: 0.3 % wt.: 0.1 % wt. and 0.15 % wt.: 0.15 % wt.: 0.1 % wt. Reaction temperatures are above 300 °C. A pressure of the system is 25 MPa for all conditions. The effect of each compound in the feedstock, temperature and residence time on product yields as well as interaction networks of glucose, xylose and guaiacol will be presented.