Optimizing Synergy between Phosphogypsum Disposal and Cement Plant CO2 Capture by the Calcium Looping Process

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• 作者：Jian Sun ; Wenqiang Liu ; Wenyu Wang ; Yingchao Hu ; Xinwei Yang ; Hongqiang Chen ; Yang Zhang ; Xian Li ; Minghou Xu
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：February 18, 2016
• 年：2016
• 卷：30
• 期：2
• 页码：1256-1265
• 全文大小：717K
• ISSN：1520-5029

文摘

In this work, a novel joint processing route that integrates the disposal of phosphogypsum waste with CO₂ emissions reduction in a cement plant was proposed. The route mainly includes three parts: direct aqueous carbonation of phosphogypsum, use of the obtained carbonation product for CO₂ capture in the calcium looping process (CLP), and manufacture of cement clinker using the spent CaO-based sorbent. The direct use of the CO₂ derived from cement plant flue gas (20 vol % CO₂) is able to convert 94.5% of CaSO₄ in the phosphogypsum into CaCO₃. However, a long time of 90 min is required for the completion of the conversion. Therefore, we proposed to introduce a part of the highly concentrated CO₂ gas stream separated from the CLP and, hence, to increase the overall CO₂ concentration of the carbonation gas stream. It was found that only 45 min is needed to achieve a comparable carbonation level when the gas stream containing 45 (or 60) vol % CO₂ was used. Moreover, the solid carbonation residues derived from phosphogypsum carbonation possess relatively good cyclic CO₂ capture performance, which is superior to the CaCO₃ reagent. It indicates that the joint processing route proposed here is feasible, which can not only recycle the phosphogypsum waste but also reduce the CO₂ emissions in the cement plant.