Factors influencing wood char gasification at macro-particle scale

The objective of the present work was first to identify the limiting phenomena during char gasification by steam and so guide us in the choice of a particle kinetic model. Then this model will have to be included in a fixed bed model developed on the basis of the results obtained. In order to achieve these goals, numerous experiments were conducted. Steam gasification of beech char spheres of different diameters (10 to 30 mm) was studied at different temperatures (830 to 1030°C), different steam partial pressures (10% to 40% H2O) and different gas velocities around the particle (0.09 to 0.30 m/s). The influence of pyrolysis heating rate ("flash", fast or slow) on gasification rate was also investigated. The apparatus used was a "macro-TGA" reactor in which the particle is suspended and continuously weighed during its gasification. (Résumé d'auteur