Online catalytic deoxygenation of vapour from fast pyrolysis of Vietnamese sugarcane bagasse over sodium-based catalysts

Abstract

Online upgrading of the obtained vapour from fast pyrolysis of sugarcane bagasse over sodium-based catalysts was studied in a fixed-bed reactor at 500°C. Over Na2CO3/γ-Al2O3 catalyst, both its physico-chemical properties and concentration of sodium salt play significant roles in its performance. Larger pore size is advantageous since it was shown to facilitate the conversion of lignin-derived high molecular weight molecules, leading to a better deoxygenation activity. Surface area and pore volume were also shown to play a certain role in the overall catalytic performance. 25wt.% of Na2CO3 was shown to be the optimum concentration in terms of deoxygenation activity which might correspond to the highest number of sodium active sites. The sodium concentration was shown to play a bigger role than the surface area and porosity in the catalytic performance of Na2CO3/γ-Al2O3 materials. On the other hand, HZSM-5, as a reference catalyst, was shown to possess deoxygenation activity that is comparable to that of Na2CO3/γ-Al2O3 catalyst. Conversion of oxygenates present in vapour into aromatic hydrocarbons was favoured in the presence of HZSM-5 catalyst while the catalytic scission of alkoxy groups in lignin-derived compounds was facilitated with Na2CO3/γ-Al2O3.