State Key Laboratory of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, People's Republic of China.
Department of Geology, Northwest University, Xi'an, 710127, Shaanxi, People's Republic of China.
Environ Sci Pollut Res Int. 2023 Mar;30(12):34009-34021. doi: 10.1007/s11356-022-24603-3. Epub 2022 Dec 12.
The direct aqueous mineral carbonation of wood combustion ash (WCA), which is a representative high-calcium waste from combustion process, was systematically investigated by varying complex operating conditions, including reaction time, liquid-to-solid ratio (L/S), CO concentration, and particle size. The WCA exhibited high CO sequestration characteristics with an optimal carbonation efficiency of 76.4%, corresponding to a CO sequestration capacity of 0.314 g CO/g WCA. In addition to solid carbonates, dry residues from liquid products with high potassium contents are potential feedstocks for quality potash fertilizer. Modified shrinking core models based on diffusion-controlled mechanism were proposed to evaluate the carbonation process. The theoretical framework assumes a contracting interface mechanism where active CaO reacts with CO to form a product layer. The effective diffusion coefficient of CO through the product layer decreases over time, giving deficient carbonation efficiency. The newly proposed models corresponding to different geometrical dimensions provided more perfect fit to the experimental data when compared with the most commonly used kinetic equations. The low apparent activation energy of the carbonation reaction demonstrated the diffusion-controlled mechanism. This work is useful for improving the economics and feasibility of bioenergy carbon capture and storage (CCS) technology chain.
通过改变复杂的操作条件，包括反应时间、液固比（L/S）、CO 浓度和颗粒大小，系统地研究了木材燃烧灰（WCA）的直接水相碳酸化作用。WCA 表现出高的 CO 捕集特性，最佳碳酸化效率为 76.4%，对应 CO 捕集容量为 0.314 g CO/g WCA。除了固体碳酸盐外，液体产物中的高钾干残渣是优质钾肥的潜在原料。基于扩散控制机制的改进收缩核模型被提出用于评估碳酸化过程。理论框架假设一个收缩界面机制，其中活性 CaO 与 CO 反应形成产物层。随着时间的推移，CO 通过产物层的有效扩散系数降低，导致碳酸化效率不足。与最常用的动力学方程相比，新提出的对应于不同几何尺寸的模型更完美地拟合了实验数据。碳酸化反应的低表观活化能表明了扩散控制机制。这项工作有助于提高生物能源碳捕获和储存（CCS）技术链的经济性和可行性。
