Production of bio-oil from agricultural waste by using a continuous fast microwave pyrolysis system

In this study, a continuous fast microwave-assisted pyrolysis system was developed to produce bio-oil, gas, and biochar from rice straw and Camellia oleifera shell. The effects of different pyrolysis temperatures (400 °C, 500 °C, and 600 °C) and feed rates (rice straw: 25, 45, and 66 g/min; C. oleifera shell: 100, 200, and 400 g/min) on bio-oil production were investigated. Experimental results showed that the yields of bio-oil (31.86 wt%) and gas (54.49 wt%) produced by the microwave-assisted pyrolysis of rice straw increased with increasing temperature. By contrast, the yields of bio-oil (27.45 wt%) and biochar (35.47 wt%) produced by the pyrolysis of C. oleifera shell decreased with increasing temperature. The contents of phenols, aldehydes, and alcohols in bio-oil produced from the shell were higher than those in bio-oil derived from rice straw.