Conclusion
Biomass gasification in supercritical water

Supercritical water gasification produces a valuable gas from wet biomass. Schematically, it involves two stages: breaking of carbon chains leading to the formation of gases, followed by reactions between these gases whose final composition at thermodynamic equilibrium is managed by three main reactions. Supercritical conditions enable us to work with moist biomass (the pressure prevents water vaporization), without prior drying of the biomass, and in a homogeneous fluid – solid medium. The gases formed are easily separated by expansion of the mixture at the end of the process.

It is possible to direct the reaction towards the production of CH₄ (and other light hydrocarbons). In this case, low temperatures have to be considered (around 450°C) and conversion yields are generally quite low. Another possible outlet is the formation of a CO/H₂ mixture, a precursor for the...