Bio-oil and biochar from microwave-assisted catalytic pyrolysis of corn stover using sodium carbonate catalyst

In the present study, bio-oil and biochar have been produced from microwave-assisted catalytic pyrolysis of corn stover (CS). The effects of microwave power (MWP) and mixing of sodium carbonate as a catalyst at different ratios have been examined. Both MWP and the catalyst improved the heating and increased the maximum temperatures of pyrolysis process. Rise in MWP increased the gas yield but decreased the biochar yield, while the bio-oil yield was not significantly affected. The use of catalyst increased the bio-oil yield and enhanced its properties. Increase in the ratios of catalyst from 10% to 30%, did not contribute a significant effect either on the yield or on the properties of the products. The water content in bio-oil was found to be in the range of 53.09–73.79%, while the minimum viscosity was observed to be 3.31 mPa s. The maximum higher heating value (HHV) of bio-oil and biochar were 13.17 MJ/kg and 29.77 MJ/kg respectively. The bio-oil samples were characterized chemically by a gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FTIR). Most of the chemical group compounds in the bio-oil were identified to be alcohol, phenols, alkynes, acids, and aromatic. The net energy recovery from the raw CS was in the range of 28.29–42.97%.