Discernment of synergism in co-pyrolysis of starch, lignin, and cellulose: Properties and reactivity of char production

Abstract

Starch, lignin, and cellulose are selected as representatives of solid waste, and the effects of these three main components and their interactions on the characteristics of the corresponding pyrolysis char are researched. The findings indicate that the interaction between starch (0.0216 min−1) and lignin (0.0203 min−1) could result in a lower oxidation reaction rate (0.0172 min−1) of the pyrolysis of their char mixture, which is associated with a slight collapse of the fibrous sheet structure. According to the comparison of the crystalline phases identified by X-ray diffractometry research, the interaction between lignin and cellulose improves the degree of carbon ordering, leading to the presence of C-faces (100) in the lignin + cellulose char sample. Raman analysis explains that the interaction between starch and lignin results in increased size and thickness of graphitic domains, and a similar trend is observed in the starch and cellulose char samples. Conversely, the band area ratio ID4/IG values of the mixed char samples are comparable to those of the two corresponding single-component char samples, indicating that no interaction occurs in the sp2–sp3 mixed structures. The results indicate that the carbon conversion increases with increasing temperature. Otherwise, the interaction between lignin and cellulose improves the degree of carbon ordering. The results of this study are anticipated to contribute to a better understanding of the mechanisms involved in the interactions of waste components on char production by pyrolysis of solid wastes.