Catalytic pyrolysis of pine wood over char-supported Fe: Bio-oil upgrading and catalyst regeneration by CO2/H2O

Char-supported metals as catalysts has attracted much attention due to the renewability and structural controllability of char. However, such catalysts can not be regenerated by the conventional calcination method, which is widely used in industy. In this study, the catalytic performance of char-supported Fe on bio-oil upgrading during pyrolysis of pine wood was first investigated. It was found that the typical components (acids, ketones, furans, etc) in bio-oil were completely converted to aromatic hydrocarbons over char-supported Fe, in which char acted not only as a support but also as a catalyst for the converison of bio-oil to phenols. Then, the spent char-supported Fe catalyst was regenerated by CO2 or steam gasification. The results showed that only phenols could be produced over both CO2 and steam regenerated catalysts, which was caused by the changes in carbon structure and surface functional groups of char as well as the species of Fe. The CO2 regenerated catalyst was rich in C = O groups and alpha-Fe2O3, while the H2O regenerated one mainly contained O = C-O groups and Fe/FeO.