Modeling of a fixed bed gasifier

One of the themes of the 'Laboratoire Thermique Energetique et Procedes de Pau' is the study and the valorization of waste as pyrolysis, combustion and gasification for example. In this context, this work deals with modeling of heat, mass and momentum transport in a multiphase multi components reactive medium for a fixed bed gasifier. Conservation equations are first written for each phase. The macroscopic partial differential equations are expressed by integrating these microscopic conservation laws over a representative volume. This change of scale, described in this work, leads to a homogeneous system of equations. This model is applied to the case of the gasification of waste process of the Europlasma company named CHOPower. The unsteady two-dimensional simulations of the problem allowed to highlight the different mechanisms present during the process and a number of locks in obtaining convergence path leading to the steady state. (author)