Pyrolysis of sesame residue: Evolution of the volatiles and structures of biochar versus temperature

Abstract

Sesame residue is a solid waste produced in the process of production of sesame oil, which can be used as feedstock for the production of biofuels and carbon materials via thermochemical process. This study explores the pyrolysis behavior of sesame residue at different pyrolysis temperatures and heating rates, aiming to explore the effects of temperature and heating rates on the distribution and properties of sesame residue products. Sesame residue contains more aliphatic alkanes and N-containing organics than biomass, and thus cracking reactions dominated distribution of products, at especially increased pyrolysis temperature with high heating rates. Majority of the nitrogen-containing organics were cracked into condensable organics at 350 °C and into gases above this temperature. The abundant long-chain aliphatics also made the bio-oil different from that from biomass pyrolysis. The organic components in sesame residual were generally not thermally stable, a significant portion of which was converted into volatile organics or gases, producing the biochar with low carbon yield, low heating value and the low energy yield. Additionally, the change of functionalities of the biochar versus temperature was investigated, providing reference information for tailoring structure of biochar for further use as functional carbon materials. • Pyrolysis of sesame residue at different temperature and heating rates was studied. • Nitrogen-containing organics was not stable and mostly cracked above 350 °C. • Cracking of alkanes in sesame residual produced abundant aliphatics in bio-oil. • Dominant cracking leads to biochar of low carbon yields and heating value. • Evolution of functionality of biochar with pyrolysis temperature was characterized.