A three-dimensional model for the determination of kinetic data from the pyrolysis of beech wood

A Three-dimensional Mathematical Model For The Pyrolysis Of Wet Wood

“…The pyrolysis of a beech wood cube with different initial moisture contents has been computed for a range of furnace temperatures. The Arrhenius kinetic parameters have been determined by a method of best fit to the experimental results of Bonnefoy et a1 [16]. The values agree very well with the range of kinetic data reported by Tinney [4].…”

“…The selected values of activation energy and pre-exponential factor are also in good agreement with the values E , = 124.7 l d mole-' and A, = 6 x lo7 -7 5 x 10' s-' reported in [4]. The pre-exponential factor, however, is higher than the value of 5 x 1 0~ s-' reported by Bonnefoy et a1 [16]. This is probably due to the absence of the moisture oo .…”

“…To determine the activation energy E , and the pre-exponential factor A,, the model has been used to simulate the pyrolysis of a wet wooden cube with an initial moisture content XO = 9 9% at furnace temperatures T, = 973 K and T, = 1273 K and the computed mass loss history has been compared with the experimental results on beech wood in [16]. Figure 2 shows the best agreement achieved between the computed and experimental mass losses vs. time for the pyrolysis of the wooden cube.…”

“…The transformed governing equations were solved numerically using a control volume technique. Simulations were performed for the pyrolysis of wooden cubes of different initial moisture contents at furnace temperatures of 973 K and 1273 K. The activation energy and pre-exponential factor for the pyrolysis reaction of the single constituent have been adjusted to fit the measured mass loss history reported by Bonnefoy et a1 [16]. Detailed results showing the transient development and distribution of the temperature, pressure, gases flow, moisture evaporation and char fraction for different furnace temperatures are presented.…”

“…In the situation of heating large cubical wood samples in furnaces, both I-D and 2-D mathematical models for wood pyrolysis cannot precisely represent the boundary conditions. Recently, Bonnefoy et a1 [16] reported a 3-D model for wood pyrolysis and obtained the kinetic data for beech wood pyrolysis using the experimental mass loss measurements. Their model, however, has not considered the moisture content and the anisotropic nature of wood, nor the convective heat transfer as a result of the internal flows of volatile gases produced in the pyrolysis processes.…”