Experimental study on pyrolysis of thermally thick biomass residues samples: Intra-sample temperature distribution and effect of sample weight (“scaling effect”)

This study on thermally thick biomass residues (brewer spent grain, fibreboard and coffee waste) pyrolysis has been investigating two aspects: temperature history and weight loss characteristics. Significant temperature gradients were measured and will affect the pyrolysis chemistry. Three temperature regimes have been identified: (1) exponentially increasing temperature, (2) linearly increasing temperature and (3) 2-slope increasing temperature with a flattening period. The regime at a given point will depend on the sample weight, the reactor temperature and the location in the sample. The exothermic step of pyrolysis was shown. The comparative study of weight loss curves obtained in a TGA and a macro-TGA shows that pyrolysis rate and duration are affected.