Characterization of the decomposition behaviors of catalytic pyrolysis of wood using copper and potassium over thermogravimetric and Py-GC/MS analysis

Characterizing the pyrolysis of inorganic matter-rich biomass is important for the preparation of bio-fuel precursors. Here, thermogravimetric and pyrolysis gas chromatography/mass spectroscopy (Py-GC/MS) were employed to elucidate the specific pyrolysis mechanisms of demineralized wood dust (AWD) impregnated with varying amounts of the inorganic compounds, copper and potassium. During the pyrolysis process, there was a dramatic decomposition of hemicellulose (at 200-320°C) and of cellulose (at 320-420 °C), along with slow lignin degradation. The decomposition of hemicellulose was substantially promoted with an increasing amount of copper. In addition, a decreased amount of aldehydes and phenols was observed, indicating a lower level of cellulose and lignin degradation, which led to more generation of bio-fuel precursors (C5-C16). In contrast to copper, potassium substantially promoted the decomposition of cellulose and lignin, but had negligible effect on hemicellulose. In the presence of both copper and potassium, the latter had a more dominant role causing an increased amount of small molecular compounds (C2-C4, i.e., from 10.91% to 22.12%), and decreased amounts of bio-fuel precursors (i.e., from 62.19% to 52.49%). The various decomposition pathways that might be involved in the catalytic pyrolysis of wood using copper and potassium are discussed.