Steam pyrolysis of an industrial waste for bio-oil production

Potato skin, a food industry waste, was pyrolysed under three different atmospheres namely static, nitrogen, and steam to produce bio-oil and its derivatives. The oil yield obtained at 550 °C was 24.77% in static atmosphere, whereas it reached to 27.11% in nitrogen atmosphere. Moreover, the use of steam caused a sharp increase of oil yields up to 41.09% with a steam velocity of 1.3 cm s− 1. TG-DTA analyses were applied on the raw material to investigate the thermal degradation. Liquid products obtained under the most suitable conditions were characterized by elemental analyses, FT-IR and 1H NMR. In addition, column chromatography was employed to separate the bio-oil into its derivatives. Asphaltene fraction of bio-oil is decreased under steam atmosphere. Gas chromatography was also used to investigate the C distributions. The characterization has shown that the bio-oil obtained under steam atmosphere was more beneficial than those obtained under both static and inert atmospheres. Further comparison of H/C ratios of pyrolysis oils with conventional fuels indicates that the H/C ratios of the oils obtained in this study lie between those of light and heavy petroleum products. It can be concluded that potato skin could be evaluated as a promising biomass candidate of bio-oil production.