| 摘要: | 為實現廢棄物資源化及應對氣候變遷造成的環境議題，世界各國陸續提出廢棄物再利用等低碳燃料相關政策，而由可適燃性廢棄物製造產出之固體再生燃料(Solid Recovered Fuel, SRF)便因運而生，這類廢棄物包含民生廢棄物，如塑膠、橡膠、木材及紙張等，再生燃料技術可有效降低傳統化石燃料需求且因低碳排而備受關注。然則若干燃料組成因含有鋁箔物質，且CFB鍋爐燃燒過程會採用石灰石作固硫劑等因素，故SRF和燃煤於CFB鍋爐進行混燒作業衍生之混燒飛灰殘留鋁金屬、游離氧化鈣等成分，使得其再利用水泥系材料中出現高度膨脹現象。
本研究旨在探討SRF衍生混燒灰渣的材料特性及再利用可行性，尤其針對具膨脹潛能的混燒灰渣，研究其內部膨脹潛勢影響及建立檢測流程，透過加濕方式進行安定化並結合水泥固化製程發展出一套系統化之混燒灰渣再利用分類指引。研究結果說明定性分析除可判斷含鋁可能外，亦能經由混合液溫度變化初步研判含f-CaO可能，結合定量分析(鋁金屬、游離氧化鈣)可使整套檢測更有效率。膨脹因子於不同狀況下影響層面及程度略有差異，在含鋁金屬前提下，若游離氧化鈣大於2%有漿體提早失去塑性疑慮，此時鋁金屬產氫將不易釋放進而加劇膨脹危害。加濕飛灰方式所需成本及設備需求低且頗具安定化效益，但面對鋁含量大於0.5%之混燒飛灰效果不彰。再利用產品方面，水泥固化製程顯示出混燒灰於海事工程應用之可行性，其中破碎材製程產出之再生粒料不僅物理性質良好且能根據破碎方式控制粒料尺寸，作為工程填築材料展現良好潛力，而原本不建議之再利用方式，再經過安定化程序後，部分混燒灰渣也得以對其作應用。
最後，基於混燒灰渣的特性，包括膨脹潛勢檢測及容許含量、加濕安定化程序及再利用方式等，進一步提出新穎的混燒灰渣再利用分類指引，包括漿料材製程、塑性材製程、破碎材製程及輔助膠凝材的適用條件，為混燒灰渣的去化和再利用提供更多元之應用途徑。;To promote waste resource utilization and address environmental challenges associated with climate change, countries around the world have introduced low-carbon fuel policies that emphasize waste reuse. Solid Recovered Fuel (SRF), produced from combustible waste such as plastics, rubber, wood, and paper, has garnered significant attention for its ability to reduce dependence on traditional fossil fuels and lower carbon emissions. However, certain SRF compositions contain aluminum foil, and the combustion process in circulating fluid-ized bed (CFB) boilers often involves the use of limestone as a desulfurizing agent. Conse-quently, the co-combustion of SRF and coal in CFB boilers produces fly ash that contains metallic aluminum and free calcium oxide (f-CaO), which can lead to significant expansion when reused in cement-based materials.
This study investigates the material characteristics and reuse potential of co-combustion ash derived from SRF, with a particular focus on ash exhibiting expansion potential. A detec-tion protocol was developed to assess internal expansion risks, and a systematic classification approach for reuse was proposed through stabilization by hydration and cement solidification processes. The results indicate that qualitative analysis can preliminarily detect the presence of aluminum and estimate the likelihood of f-CaO based on temperature changes in the mix-ing solution. When combined with quantitative measurements of metallic aluminum and f-CaO, the overall detection process becomes more effective and efficient. The expansion behavior varies under different conditions. In cases where aluminum is present and the f-CaO content exceeds 2%, the slurry may lose plasticity prematurely, impeding hydrogen release from the aluminum and thereby intensifying expansion issues. Hydration treatment is a low-cost and effective method for stabilization; however, its performance diminishes when the aluminum content exceeds 0.5%. In terms of reuse applications, the cement solidification process demonstrates the feasibility of utilizing co-combustion ash in maritime engineering. Additionally, the production of recycled aggregates through crushing processes yields mate-rials with favorable physical properties. The particle size of these aggregates can be con-trolled based on the crushing method, making them suitable for use as construction fill. Some previously unsuitable reuse methods may become viable after stabilization.
Finally, based on the characteristics of co-combustion ash—including expansion risk detection and content thresholds, hydration stabilization, and reuse strategies—this study proposes a novel classification guideline for the reuse of SRF-derived co-combustion ash. The guideline outlines appropriate conditions for slurry-based materials, plastic-like materi-als, crushed aggregates, and supplementary cementitious materials, offering diversified pathways for the treatment and resourceful reuse of co-combustion ash. |
