Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.
Fire Dynamics Simulator (FDS) and global modelling are used to solve numerically pyrolysis, combustion and heat recuperation in a pilot plant of biomass pyrolysis using pyrolysis products as fuel. Obtained results are validated with experimental measurements. In the case of FDS modelling three different treatments of radiation are considered: without radiation, with gray gas radiation and with non gray gas radiation. The results of numerical simulations are compared with the global model results and with the experimental results. It was shown that the FDS results are in good qualitative and quantitative agreement with the experimental results. The global model gives qualitative results in agreement with experimental results with less CPU time compared with FDS results. Whereas FDS results are more accurate than those of the global model. At the end of the process FDS results are better than global model results this is due to the fact that global model doesn’t take into account the thermal inertia of the pilot plant. The global model is used to study the racing reaction in the pilot plant and to study the case with and without catalyser. FDS is used to predict CO and CO2 emissions. The effect of the non gray gas behaviour is emphasised and demonstrated to affect pollutant emissions.