Investigation of Vaporization of Alkali Metals from Solidified Gasifier Slags by Knudsen Effusion Mass Spectrometry

详细信息    查看全文

• 作者：L. Bencze ; M. Ry?-Matejczuk ; E. Yazhenskikh ; M. Ziegner ; M. Müller
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：January 21, 2016
• 年：2016
• 卷：30
• 期：1
• 页码：657-665
• 全文大小：464K
• ISSN：1520-5029

文摘

One problem in coal gasification is the release of alkali species, which can cause fouling and corrosion. Depending on their composition, slags have a high potential for alkali retention. Therefore, the vapor pressures of alkali species (Na, K) over four real solidified gasifier slag samples were determined over the temperature range 1134 to 1591 K by Knudsen effusion mass spectrometry (KEMS). In addition, the residues from the KEMS investigations were studied by X-ray diffraction (XRD) and scanning electron microscope/energy dispersive X-ray (SEM/EDX) to determine the phase composition of the samples and map the alkali distribution. A strong correlation between the composition of the slags in terms of amount of acidic oxides (SiO₂, Al₂O₃) and basic oxides (CaO, FeO) and the volatility was determined. The volatility results showed that higher acidic oxide content leads to higher alkali retention capability. The XRD and SEM/EDX analysis of the KEMS residues showed that an anorthite type phase contains more Na than all the other phases in the equilibrium.