A model for pyrolysis of wet wood

✍ Scribed by S.S. Alves; J.L. Figueiredo

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 879 KB
• Volume: 44
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(89)85096-1

✦ Synopsis

A mathematical model of the pyrolysis of wet particles of wood is presented. The model integrates: (i) a conventional description of the physical and chemical phenomena involved in the pyrolysis pf dry particles of wood, and (ii) a simplified drying model. The dry-pyrolysis model assumes a complex reaction scheme independently determined. The most important parameters were experimentally measured, including the thermal conductivities and all the kinetic parameters; other parameters were taken as average values from the literature. The drying model neglects bound-water diffusion, air/vapour diffusion and pressure gradients inside the solid. Free-water movement is not described. Drying is therefore controlled by heat supply. These assumptions restrict the model validity range to: (a) temperatures higher than 15O"C, (b) initial moisture content below the free-water continuity point (-45%), and (c) sample dimension in the wood longitudinal direction not much greater than the dimensions in the transversa1 directions. The combined wet pyrolysis model has been experimentally validated in the simulation of: (i) drying of pine wood cylinders of variable diameter above 15O"C, and (ii) pyrolysis of dry and wet cylinders of pine wood of variable diameter between 300 and 800°C. No parameter optimization was required.