Mechanism of supercritical water gasification of corn stover for hydrogen-rich syngas: Composition of reaction products

Abstract

Hydrogen-rich syngas from supercritical water gasification (SCWG) of renewable biomass is a promising technology. However, due to the complexity of the biomass structure, there is limited research on the liquid and solid products generated by SCWG of real biomass, and the related hydrolysis and gasification mechanisms are not yet clear. In this study, SCWG experiments were carried out on corn stover through a batch reactor, and the products were analyzed by gas-phase GC, liquid-phase GC-MS, UV spectroscopy, ultimate analysis, FTIR, PY-GC/MS, BET specific surface area, and SEM. The mechanism of corn stover SCWG was revealed by qualitative and quantitative analyses of gas products, the composition of liquid products, and the functional groups, carbon skeleton, surface morphology and specific surface area of solid products. The results showed that the aliphatic groups were hydrolyzed and gasified first at 400–500 °C. When the temperature rose to 600 °C, the aromatic groups were also gradually hydrolyzed and gasified, and the remaining aromatic groups underwent condensation and dehydrogenation to produce large molecular naphthalene, phenanthrene, pyrene, etc. The optimal biomass concentration was between 10.5 and 1 g/100 g water during the corn stover SCWG, and the reaction was completed in 15 min.