Detailed numerical modeling of pyrolysis in a heterogeneous packed bed using XDEM

The aim of this investigation is to predict pyrolysis of biomass in a packed bed. The eXtended Discrete Element Method (XDEM) as a simulation framework is proposed to predict the heat transfer, drying and pyrolysis of biomass in a packed bed. This allows determination of the detailed information about each single particle and the whole bed as well, which is very important to understand the complex process in the packed bed. XDEM is considered as an Euler-Lagrange model, where the fluid phase is a continuous phase and each particle is tracked with a Lagrangian approach. The particle model itself is based on one-dimensional and transient differential conservation equations for mass, momentum, species and energy. However gas phase is modeled in three-dimensional and behaves more like an external flow through the void space, formed by particles in the reactor. The model has been compared to experimental data for a wide range of temperatures. Good agreement between simulation and measurement proves the ability of the model to predict pyrolysis of packed bed; therefore it can be used as a reliable tool for designing gasification devices.