Study about the kinetic processes of biomass steam gasification

Modelling approaches of biomass steam gasification are investigated that take into account both chemical and physical kinetic limitations. The gas phase can be described by two independent reactions: (i) the steam reforming of CH4, which is kinetically limited under the operating conditions (1073 < T < 1273 K, p = 1 bar), (ii) the water–gas shift reaction, which would be close to equilibrium under the operating conditions (1073 < T < 1273 K, p = 1 bar). Concerning solid, a time scale analysis of the main phenomena has been performed. For particles of 500 μm, the transformation can be seen as two successive steps: (i) pyrolysis of biomass, which is both chemically and heat-transfer controlled; (ii) steam gasification of residue, which is chemically controlled.