Treatment of wood pyrolysis data via a multiple gas-solid reaction model

Wood pyrolysis consisting of water evaporation, consecutive, and parallel r eactions was modeled through a multiple gas-solid reaction scheme. Effectiv e kinetic parameters were determined through the model and compared to the results of a conventional differential method where the results differed su bstantially. The behavior of global wood conversion is compared to the expe rimental results. System parameters and variables, transport coefficients, and thermophysical proper ties are determined transiently. The millimeter s ized pellets were found to have substantial gradients within. The heating r ate of thermogravimetric analysis equipment is also considered in the model . The rate expressions were developed based on molar solid concentrations i n the wood fibers. For the simulation grain (pore or fiber), pellet and rea ctor spaces of different magnitudes were considered. The effective quantiti es were DeltaE(1) = 255.7 kJ/mol, k(10) = 8.5 x 10(18) s(-1), DeltaE(3) = 4 0.7 kJ/mol, and k(30) = 4 x 10(6) s(-1).