Department of Environmental Studies for Advanced Society, Graduate School of Environmental Studies, Tohoku University, 468-1, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-0845, Japan.
Center for Mineral Processing and Metallurgy, Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan.
J Environ Manage. 2021 Jun 15;288:112411. doi: 10.1016/j.jenvman.2021.112411. Epub 2021 Apr 7.
Environmental impacts from coal-fired power generation that produces large amounts of CO and fly ash are of great interest. To reduce negative environmental impacts, fly ash utilization was investigated via a direct aqueous carbonation with a low-energy input in which the alkali calcium content in the fly ash reacted with CO to form carbonate. Raw fly ash was characterized to understand the potential for direct aqueous carbonation of fly ash. The performance of the fly ash as a calcium source for direct aqueous carbonation at atmospheric pressure was investigated for different solid-liquid ratios and introduced CO concentrations. Variations in fly ash elemental composition, reaction solution pH, CO concentration in the reactor outlet, CO uptake efficiency, CaCO content and degree of carbonation were used to illustrate this process reaction. The maximum CO uptake efficiency was ~0.016 g-CO/g-fly ash. This value was compared with previous studies, and the CO uptake efficiency was comparable despite the use of a low-energy input method, i.e., direct aqueous carbonation with atmospheric pressure and unconcentrated CO. The calculated maximum degree of carbonation was 31.0%, which corresponds to 0.0063 g-CO/g-fly ash. Carbonated product characterization confirmed the carbonation reaction mechanism and safety for further utilization. A comparison of CO uptake efficiency in this work with previous work, and considering the energy input and reactive species content, is provided. An assessment of the CO reduction potential is provided.
燃煤发电会产生大量的 CO 和粉煤灰，对环境造成巨大影响。为了减少负面影响，研究了通过低能耗的直接水合碳酸化作用来利用粉煤灰，粉煤灰中的碱钙成分与 CO 反应生成碳酸盐。对原始粉煤灰进行了特性分析，以了解粉煤灰直接水合碳酸化的潜力。研究了不同固液比和引入的 CO 浓度下，粉煤灰作为直接水合碳酸化钙源的性能。粉煤灰元素组成、反应溶液 pH 值、反应器出口处 CO 浓度、CO 吸收效率、CaCO3 含量和碳酸化度的变化用于说明这一反应过程。最大 CO 吸收效率约为 0.016 g-CO/g-粉煤灰。将该值与以前的研究进行了比较，尽管使用了低能耗输入方法，即常压和未浓缩 CO 的直接水合碳酸化，但 CO 吸收效率相当。计算出的最大碳酸化度为 31.0%，相当于 0.0063 g-CO/g-粉煤灰。碳酸化产物的特性分析证实了碳酸化反应机制和进一步利用的安全性。与以前的工作相比，对 CO 吸收效率进行了比较，并考虑了能量输入和反应物种含量。还提供了 CO 减排潜力的评估。
