Pyrolysis of soybean residue: Understanding characteristics of the products

Soybean residue (SR) is a main solid waste produced during the extraction of soybean oil with bulk volume. In addition to the use as vegetable protein feed, SR could also be used as feedstock for producing biofuels and carbon materials via pyrolysis. In this study, the pyrolysis behaviors of SR at varied temperatures and heating rates were investigated. The results show that the pyrolysis of the organic components in SR could reach completion even at 500 degrees C, due to the lower thermal stability of the organic component than that in the typical biomass. This also leads to the bio-oil with little heavy organics and also low carbon content of the resulting biochar, as the organic components decomposed to a significant extent while the charring reactions were insignificant. This leads to the biochar with low heating value and low energy yield when compared with that in the pyrolysis of typical biomass. In addition, the high content of proteins, amino acids and other nitrogen-containing nutrients make the SR derived bio-oil nitrogen-rich and a significant portion of nitrogen could also be retained in the biochar. These specialties have to be considered during their applications as either biofuels or functional carbon materials. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Soybean residue can be used as feedstock for biofuels and carbon materials, with organic components being able to be completely decomposed at 500 degrees Celsius; resulting bio-oil has little heavy organics, and biochar has low carbon content, heating value, and energy yield compared to typical biomass pyrolysis; bio-oil derived from soybean residue is nitrogen-rich, and a significant amount of nitrogen can also be retained in the biochar.