In-situ catalytic upgrading of bio-oils from rapid pyrolysis of torrefied giant miscanthus (Miscanthus x giganteus) over copper-magnesium bimetal modified HZSM-5

In this study, fast pyrolysis of both raw and torrefied giant miscanthus (GM) is investigated in detail. It is found that the pyrolysis of torrefied GM results in higher distribution of phenols and aliphatic compounds in bio-oil with lower moisture content. To further improve the bio-oil quality, catalytic upgrading process of the bio-oil from the torrefied GM over copper-magnesium (Cu-Mg) bimetal doped zeolites is also investigated. As a result, a highest yield of aromatic hydrocarbons of 63.1% favoring in higher monoaromatic hydrocarbons such as benzene, toluene and xylene in the upgraded bio-oil is obtained as GM-300 is used as feedstock and HSZ-Cu 2:1 Mg as the catalyst. It is found that Cu-Mg doping can not only enhance catalytic activity of zeolite but also maintain relatively low coke deposition and improve the catalyst reusability. Besides, the spent catalysts are easily regenerated only by a facile calcination way, and the regenerated catalyst shows almost the same activity as the initial one.