THM University of Applied Sciences, Competence Centre for Sustainable Engineering and Environmental Systems (ZEuUS), Wiesenstr. 14, D-35390 Gießen, Germany.
THM University of Applied Sciences, Competence Centre for Sustainable Engineering and Environmental Systems (ZEuUS), Wiesenstr. 14, D-35390 Gießen, Germany.
Waste Manag. 2021 Apr 15;125:40-48. doi: 10.1016/j.wasman.2021.02.027. Epub 2021 Mar 4.
Bottom ash (BA) is the dominant residue derived from the incineration of municipal solid waste or refuse-derived fuel (RDF). Costs for the disposal of the material chiefly depend on the leachability of salts and trace metals which may be cut by ageing the BA for several months to promote carbonation via uptake of carbon dioxide (CO). Enhanced exposure to CO sources has been referred to as accelerated carbonation. Here we report on the successful implementation of the accelerated carbonation of BA in a continuously fed full-scale rotating drum reactor. The reactor was operated with the fine fraction (< 20 mm) of BA from an RDF incinerator and the exhaust of a combined heat and power unit was used as the reactant gas. The system was tested in 15 experiments and the process efficiency was addressed by maximizing the reactor loading and minimizing the BA residence time. Results confirmed that the reactor loading depended on the rotation-normalized mass flow rate of BA where the slope and intercept of the characteristic varied with the design of the reactor discharge and the use of mixing tools. According to leaching test results, BA residence times as low as 60 min were sufficient to render the carbonated BA a non-hazardous waste and convert it to a material suited for geotechnical applications. This outperforms previous laboratory findings and opens new perspectives for implementing the accelerated carbonation at incinerator sites.
底灰 (BA) 是城市固体废物或垃圾衍生燃料 (RDF) 焚烧产生的主要残留物。该材料的处置成本主要取决于盐和痕量金属的浸出性，这些盐和痕量金属可以通过将 BA 老化数月以促进碳酸化来减少，碳酸化通过吸收二氧化碳 (CO) 来实现。增强对 CO 源的暴露被称为加速碳酸化。在这里，我们报告了在连续进料的全规模旋转鼓式反应器中成功实施 BA 的加速碳酸化。该反应器使用来自 RDF 焚烧炉的细颗粒 (<20mm) 和联合热电联产装置的废气作为反应气体进行操作。该系统在 15 次实验中进行了测试，并通过最大程度地提高反应器负荷和最小化 BA 停留时间来解决工艺效率问题。结果证实，反应器负荷取决于 BA 的旋转归一化质量流速，其中特征的斜率和截距随反应器排放的设计和混合工具的使用而变化。根据浸出试验结果，BA 的停留时间低至 60 分钟就足以使碳酸化 BA 成为非危险废物，并将其转化为适合岩土工程应用的材料。这优于以前的实验室发现，为在焚烧厂实施加速碳酸化开辟了新的前景。
