The gasifier model has been improved from earlier models
[40e42] developed by the authors, and already validated [43].
De-volatilization is a very complex process and the products
distribution and yield are particularly sensitive to the heat
rate and the residence time in the reactor. The pyrolysis
products include gas compounds like CO2, CO, H2O, H2, and
CH4, light and heavy hydrocarbons (tar) and char. In fluidized
bed gasifiers, the pyrolysis reactions were considered as
instantaneous: for this reason pyrolysis products of biomass
gasification were used as input for the model instead of solid
biomass. The composition of the pyrolysis products was obtained
by experimental tests on a bench scale fluidized bed
reactor carried out at temperature close to those adopted for
the simulations (750e800 C) using nitrogen as fluidizing
media and olivine as bed material: more details on the test rig
and on the operating condition can be found in the work of
Vecchione et al. [43].