Experimental and Thermodynamic Analyses of Trace Element Speciation during the Combustion of Ground Cedar Nut Shells

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• 作者：Wojciech Jerzak
• 刊名：Energy & Fuels
• 出版年：2017
• 出版时间：February 16, 2017
• 年：2017
• 卷：31
• 期：2
• 页码：1969-1979
• 全文大小：946K
• ISSN：1520-5029

文摘

The objective of this paper was to identify trace elements present in cedar nut shells and the products of their combustion. In the fuel, the following trace elements (TEs) were identified (mentioned in the order from the highest content): Zn, Cu, Cr, Ni, Ba, Sn, V, Mo, Pb, Sr, Sb, As, Co, and Cd. Among the 14 TEs detected in cedar nut shells, zinc has the highest content of 23 mg/kg in the dry fuel. The influence of the combustion temperature from the range of 800–1200 °C on the change of the molar fraction of certain species containing TEs in the combustion products was determined on the basis of equilibrium calculations carried out in FactSage 6.3 software. It has been demonstrated that the combustion of cedar nut shells in the temperature range of 800–900 °C preserves the following elements in the ashes: Zn, Cu, Ni, Ba, Sn, and As, whereas Sb and Cd are present only in the flue gas. The molar fractions have been determined for the dominating species containing TEs in the flue gas and ashes. The presence of elements in the bottom ash after biomass combustion in the temperature of 830 ± 25 °C has been confirmed by the X-ray diffraction (XRD) and scanning electron microscopy (SEM) hyphenated with energy-dispersion spectroscopy (EDS) methods. From the XRD analyzes, it seems that dominating species containing TEs in the ashes are Ca₃(VO₄)₂ in monoclinic and trigonal crystal systems, SrTiO₃ in the regular crystal system, and ZnFe₂O₄.