Understanding the Competition Mechanism between Na<sub>2</sub>O and CaO for the Formation of the Initial Layer of Zhundong Coal Ash

Maierhaba Abudoureheman; Lanzhen He; Kunpeng Liu; Bo Wei; Jia Lv; Jianjiang Wang; Quan Zhu

doi:10.3390/en17133172

Energies (Jun 2024)

Understanding the Competition Mechanism between Na<sub>2</sub>O and CaO for the Formation of the Initial Layer of Zhundong Coal Ash

Maierhaba Abudoureheman,
Lanzhen He,
Kunpeng Liu,
Bo Wei,
Jia Lv,
Jianjiang Wang,
Quan Zhu

Affiliations

Maierhaba Abudoureheman: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China
Lanzhen He: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China
Kunpeng Liu: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China
Bo Wei: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China
Jia Lv: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China
Jianjiang Wang: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China
Quan Zhu: State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, School of Chemical Engineering and Technology, Xinjiang University, Urumqi 830017, China

DOI: https://doi.org/10.3390/en17133172
Journal volume & issue: Vol. 17, no. 13
p. 3172

Abstract

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The contents of alkali and alkaline earth metals are higher in Zhundong coal, and there are serious problems of slagging and fouling during the combustion process. Therefore, it is of great significance to reveal the mechanism of slagging and fouling in the boiler of Zhundong coal. In this paper, first-principle calculations based on density functional theory are used to study the competition mechanism of alkaline metal oxides during the combustion process in Zhundong coal by establishing the Na2O(110)/CaO(100)-SiO2(100) double-layer interface model. The results show that the bond lengths of the surface of Na2O(110) and CaO(100) with SiO2(100) after adsorption were generally lengthened and the value of bond population became smaller, which formed a stable binding energy during the reaction. The electron loss of Na is 0.05 e, the electron loss of Ca is 0.03 e, and the electron loss of Na2O is greater than that of CaO. The charge transfer on the surface of Na2O with SiO2 is obviously higher than that of CaO and the orbital hybridization on the surface of CaO with SiO2 is weaker than that on the surfaces of Na2O with SiO2. Na2O is easier to react with SiO2 than CaO. The adsorption energies on the surface of Na2O and CaO with SiO2 are −5.56 eV and −0.72 eV, respectively. The adsorption energy of Na2O is higher than that of CaO, indicating that Na2O is more prone to adsorption reactions and formation of Na-containing minerals and other minerals, resulting in more serious slagging. In addition, the XRD analyses at different temperatures showed that Na-containing compounds appeared before Ca-containing ones, and the reaction activity of Na2O is stronger than that of CaO in the reaction process. The experimental results have good agreement with the calculation results. This provides strong evidence to reveal the slagging and fouling of Zhundong coal.

Published in Energies

ISSN: 1996-1073 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Technology
Website: http://www.mdpi.com/journal/energies

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