Waste Wood Characterization and Combustion Behaviour in Pilot Lab Scale

This work aims at testing the suitability of waste wood as feedstock in an industrial combustion unit. Firstly, an extensive characterization of properties relevant for combustion was performed on two samples of waste wood and one sample of natural wood for comparison. Both waste wood samples were found to contain significantly higher amounts of metals such as iron and titanium than natural wood. However, one sample was much richer than the other one in all types of impurities, which resulted in a particularly high amount of ash (about 10 w %), and the sample was also found to contain many fine particles. These observations seemed to be explained by an external pollution of the sample by soil. Then, experiments were carried out in a bench-scale fixed-bed combustion unit on the different samples under variable conditions of air flow. All samples could be successfully burnt. However, the waste wood sample polluted with soil appeared to have a lower conversion rate due to its heterogeneity of particle size. A separation between fines and the rest of the sample seemed to solve this issue. Regarding gas emissions, as expected, both waste wood samples gave rise to higher amounts of NOx emissions than natural wood due to their content.