Bio-oil production from the catalytic pyrolysis of raw and torrefied corn waste by using MgO and CaO catalysts

This research investigates the influence of torrefaction and catalytic pyrolysis of raw corn waste (RCW) to upgrade the quality of bio-oil. RCW was torrefied at 280°C for 16 mins to produce torrefied corn waste (TCW). Natural basic oxides (CaO and MgO) catalysts were selected because of inexpensive and high catalytic performance. Pyrolysis experiments were conducted in a bench-scaled bubbling fluidized bed reactor at 500°C. The effects of torrefaction and the presence of a catalyst on the pyrolysis product both yield and composition were investigated. The results from non-catalytic pyrolysis revealed that TCW pyrolysis gave 15 wt.% lower in oil yield, and about 6.8 wt.% lower in gas yield but the char yield was approximately 22 wt.% higher compared to the pyrolysis of RCW. Considering the effect of catalyst, the yield of bio-oil reduced slightly, while the yield of char and gas increased compared to non-catalytic pyrolysis for both RCW and TCW. The bio-oil composition derived from TCW pyrolysis contained more phenolic and aromatic compounds and significantly lower oxygenated compounds when compared to that of RCW pyrolysis. Moreover, with the presence of the catalysts, the bio-oil composition and HHVs of bio-oil was also improved.