Catalytic pyrolysis of waste rice husk over mesoporous materials

Catalytic fast pyrolysis of waste rice husk was carried out using pyrolysis-gas chromatography/mass spectrometry [Py-GC/MS]. Meso-MFI zeolite [Meso-MFI] was used as the catalyst. In addition, a 0.5-wt.% platinum [Pt] was ion-exchanged into Meso-MFI to examine the effect of Pt addition. Using a catalytic upgrading method, the activities of the catalysts were evaluated in terms of product composition and deoxygenation. The structure and acid site characteristics of the catalysts were analyzed by Brunauer-Emmett-Teller surface area measurement and NH₃ temperature-programmed desorption analysis. Catalytic upgrading reduced the amount of oxygenates in the product vapor due to the cracking reaction of the catalysts. Levoglucosan, a polymeric oxygenate species, was completely decomposed without being detected. While the amount of heavy phenols was reduced by catalytic upgrading, the amount of light phenols was increased because of the catalytic cracking of heavy phenols into light phenols and aromatics. The amount of aromatics increased remarkably as a result of catalytic upgrading, which is attributed to the strong Brönsted acid sites and the shape selectivity of the Meso-MFI catalyst. The addition of Pt made the Meso-MFI catalyst even more active in deoxygenation and in the production of aromatics.