Circular indirect carbonation of coal fly ash for carbon dioxide capture and utilization
Circular indirect carbonation of coal fly ash for carbon dioxide capture and utilization
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DOI：
10.1016/j.jece.2022.108269
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发表时间：
2022-07
影响因子：
7.7
通讯作者：
Hsing-Jung Ho;A. Iizuka;E. Shibata;T. Ojumu
中科院分区：
文献类型：
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作者：
Hsing-Jung Ho;A. Iizuka;E. Shibata;T. Ojumu
碱性废弃物的矿物碳酸化是一种很有前途的CO2捕集和利用途径。探索相对惰性碱性废弃物的碳酸化潜力，对发展矿物碳酸化具有重要意义。燃煤电厂产生大量粉煤灰，必须进行处理。对粉煤灰循环间接碳酸化进行了基础性研究，并对粉煤灰浸出、碳酸钙沉淀和双极膜电渗析（BPED）再生过程进行了研究。在浸出阶段，硝酸/钙比影响溶液pH和杂质浓度。杂质的浸出行为主要与胶体沉淀有关。约97.3%的钙在溶液中反应形成沉淀碳酸钙，并获得较高纯度的碳酸钙沉淀时，较低的硝酸/钙比在浸出阶段使用。CO2转化率为92.9%，CO2吸收效率为0.011 g-CO2/g-飞灰，通过优化净化工艺可以提高CO2吸收效率。进行基本的液体纯化。通过研究电位和电流密度对再生产率、电流效率和功耗的影响，评价了BPED溶液再生。综合评价了循环间接碳酸化的成本和CO2平衡，并对今后的研究方向提出了建议。
Mineral carbonation of alkaline wastes is a promising route for carbon dioxide (CO2) capture and utilization. An exploration of the carbonation potential of relatively inert alkaline wastes is important to develop mineral carbonation. Large amounts of coal fly ash are generated from coal-fired power plants and must be treated. A fundamental study of the circular indirect carbonation of coal fly ash was proposed and fly-ash leaching, calcium carbonate (CaCO3) precipitation, and solution regeneration with bipolar membrane electrodialysis (BPED) stages were investigated. In the leaching stage, the nitric acid/calcium ratio affected the solution pH and impurity concentration. The leaching behavior of impurities was related mainly to colloidal precipitation. Approximately 97.3% calcium in solution reacted to form precipitated CaCO3, and a higher-purity CaCO3precipitate was obtained when a lower nitric acid/calcium ratio was used in the leaching stage. The CO2conversion was 92.9% and the CO2uptake efficiency was ~0.011 g-CO2/g-fly ash, which can be improved by optimizing the liquor purification process. Fundamental liquor purification was performed. Solution regeneration by BPED was evaluated by investigating the effect of electric potential and current density on the regeneration yield, current efficiency, and power consumption. A comprehensive assessment, including cost and CO2balance, was conducted, and future interesting research on circular indirect carbonation was suggested.