Sequence-based Process Modeling of Fluidized Bed Biomass Gasification

Abstract

Despite tremendous effort to model fluidized bed biomass gasifiers, as major sustainable waste-to-energy devices, current equation-oriented approaches suffer from implementation difficulties. In this research, a comprehensive cocurrent sequence-based process model is introduced to simulate bottom-fed bubbling fluidized bed biomass gasifiers (BFBGs). The gasifiers include two operating regions, namely dense bed and freeboard. The dense bed is divided into several sections of logically ordered ideal reactors to describe the behavior of interacting phases, i.e., bubble and emulsion. The bubble phase is well characterized by an ideal plug flow reactor (PFR), and the emulsion phase is simulated as a continuous stirred-tank reactor (CSTR). The freeboard is successfully mimicked with a PFR. Hydrodynamic and kinetic submodels describe physical and chemical phenomena taking place in the gasifiers, respectively. A dynamic two phase model is adopted as the hydrodynamic submodel, and the kinetic submodel is derived f...