Comparing the thermal conversion behavior of bio-wastes in three molten nitrates. (August 2022)

• Record Type: Journal Article
• Authors: Yang, Yuhan; Wang, Tiancheng; Zou, Chan; Xu, Kai; Hu, Hongyun; Gao, Linxia; Li, Xian; Yao, Hong
• Is Part Of: Renewable energy. Volume 196(2022)
• Page Start: 617
• Page End: 624
• Publication Date: 2022-08
• Subjects: Bio-wastes -- Clean utilization -- Molten nitrate -- Thermal conversion behavior -- Nitrification; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2022.06.123
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: Molten salt could act as both heat transfer fluid and catalyst in bio-waste pyrolysis. The temperature and composition of anions and cations of molten salts have significantly different effect on the pyrolysis behavior of bio-waste. In this study, three kinds of molten nitrates have been applied to conduct thermal conversion experiments of two kinds of bio-waste (beech and waste paper). The results showed that NO2 − has a higher reactivity towards the bio-waste than NO3 − . In detail, a faster reaction rate of biowaste pyrolysis and higher yield of gas products were found in NaNO3 –KNO3 –NaNO2 and NaNO3 –NaNO2 than NaNO3 –KNO3 . From the GC-MS analysis, it can be concluded that K + inhibited the dehydroxylation process of phenols at 300 °C, while the phenols were completely converted to the aromatic hydrocarbonas the temperature went up. In addition, nitrogenous heterocycle was produced due to the reaction between furans, aldehydes, ketones and NO2 − /NO3 −, and the nitration process was found to be enhanced as the temperature rose. Inorganic components contained in bio-waste remaining in molten salt may affect its catalytic properties. Therefore, the effect of KCl–K2 SO4 –CaCO3 on the pyrolysis behavior of bio-waste in molten nitrate was also investigated. The inorganic components increased the weight loss temperature, while the thermal conversion of bio-wastes was promoted after reaching the reaction temperature. The study in this paper provides guidance for the selection of appropriate molten nitrate system and temperature for bio-waste treatment. Graphical abstract: Image 1