Activated Semi-coke in SO2 Removal from Flue Gas: Selection of Activation Methodology and Desulfurization Mechanism Study

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• 作者：Zheng Yan ; Lili Liu ; Yueling Zhang ; Jinping Liang ; Jinping Wang ; Zuotai Zhang ; Xidong Wang
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：June 20, 2013
• 年：2013
• 卷：27
• 期：6
• 页码：3080-3089
• 全文大小：588K
• 年卷期：v.27,no.6(June 20, 2013)
• ISSN：1520-5029

文摘

Activated semi-coke, an economical carbonaceous material, is employed in the removal of SO₂ from simulated flue gas of an industrial power plant. Activation by four commonly used agents, including CO₂, KOH, ZnCl₂, and H₃PO₄, is studied in detail, which demonstrates that the sample treated with KOH at high temperature presents the best performance on removal of SO₂. Further investigation on the physical and chemical properties reveals that both optimized pore structure and increased amount of active sites of activated semi-coke could contribute to the high desulfurization capacity. The semi-coke activated with KOH is selected to discuss possible mechanisms of the adsorption and desorption processes. Performances with variation of desulfurization temperatures evidence that physically adsorbed SO₂ can transform into chemically adsorbed SO₂, which is significantly affected by temperature. Desulfurization behaviors under different flue gas compositions show that oxidation of SO₂ to SO₃ plays a key role in SO₂ removal. By the analyzing desorption behavior of the samples, a reactive intermediate, C(O) complex, is proposed to be generated by dissociated chemisorption of O₂ onto the surface of activated semi-coke, which serves as the dominating active site in oxidation of SO₂. Besides, activated semi-coke exhibits several favorable properties in this study that could offer the prospect for further application in industrial desulfurization.