Gasification of Solid Fuels: Multi-scale Approach

The paper investigates the different scales involved in the modeling of equipment for the gasification of solid fuel. Specifically, the code GasDS is described as comprehensive model of a biomass gasifier on a travelling grate. This general mathematical model deals with the complex multiphase gas-solid problem of biomass gasification both at the reactor and particle scales. Mass and energy balances plus proper closure equations describe the behavior of both the phases. Key elements of the model are the detailed kinetic schemes describing the biomass volatilization, including the formation of TAR species and char, and the secondary gas phase as well as the heterogeneous reactions. The model has been already tested and validated on semi-quantitative basis in comparisons with a 12 MW biomass combustor operating in Belgium. This paper extends the model and the comparison to recent experimental data obtained in a biomass regenerative gasifier. The comparison with experimental data highlights the role of devolatilization, mass transfer phenomena, and mainly the kinetics of char gasification in controlling system’s reactivity and syngas composition.