Catalytic hydrothermal upgrading of pyrolysis oil
Pyrolysis oil from wood pellets was upgraded in this research by catalytic hydrotreatment in a 100 ml batch reactor. Four heterogeneous 5% metal catalysts (Ru, Ni, Rh, and Ni) were used at different hydrotreatment temperatures (250 ºC and 300 ºC). Two different set-ups were also used with formic acid and with only bio-oil. The products of the reforming using two temperature conditions were then analysed and compared. The results showed that higher temperature yielded a lot of char compared to lower temperature giving low bio-oil recovery and poor carbon yield in the bio-oil. Also higher temperature resulted into the production of more carbon dioxide gas and hydrocarbon gases. Ru catalyst appeared to be the best among all the catalysts in reducing the amount oxygen wt-% by 42.12% at 250 ºC. Ru treated bio-oil also registered the highest composition of the lightest compounds of about 88.5% compared to initial bio-oil which only had 30.6%. Elemental analyses results show that all the upgraded bio-oils displayed lower oxygen content than the raw bio-oil with increased hydrogen and carbon composition.