Detailed process modeling of a wood gasification combined heat and power plant

We provide the first process simulation able to depict a complete life cycle inventory of a biomass gasification combined heat and power (CHP) plant. The model predicts the detailed mass and energy balances, minor compounds emissions (such as NOx, SOx, aromatics, etc.). It is based on a phenomenological approach for dryer, reactors (gasification and combustion) and scrubber modeling. Process units are modeled with Aspen Plus/C210 models completed with dedicated Fortran sub-models when more details are required. The gasifier is a Dual Fluidized Bed (DFB). It is decomposed in three sections, describing the three main mechanisms occurring in the reactor: wood pyrolysis, secondary reactions and char combustion. At the outlet of the gasifier, the complete composition of the syngas is predicted, which includes water, permanent gases, inorganics, particles and tars (phenol, benzene, toluene, styrene, indene, naphthalene, acenaphthylene, anthracene, phenanthrene, pyrene). Simulation results were validated against measurements from a pilot plant and other literature data. A wet conventional syngas cleaning system for gasification plant was considered and modeled. Gaseous emissions (NOx, SOx, etc.) of the gas engines and the DFB combustor are also handled by the model as well as ashes and liquid waste. The predicted electrical and thermal efficiency.