| 摘要: | 本研究使用纖維、塑膠及紙渣等，三種不同來源種類製成的固體再生燃料（Solid Recovered Fuel, SRF）於流體化床鍋爐進行混燒試驗。研究結果顯示，使用SRF對於鍋爐的燃料投料控制、蒸汽輸出及鍋爐溫度操控，都符合鍋爐穩定操作之條件，且鍋爐熱效率都可達80%以上。根據SRF之元素分析結果顯示，其氮含量及氯含量皆高於燃煤，而硫含量低於燃煤。在混燒結果中，鍋爐的脫硫系統及脫硝系統，去除效率皆高於95%以上，煙囪排氣中SO2、NOX及HCl皆可符合法規標準。
混燒SRF鍋爐衍生的飛灰及底渣分析結果顯示，毒性特性溶出程序(TCLP)各金屬溶出濃度皆低於法規標準的20%以下；SRF飛灰及底渣的戴奧辛及呋喃毒性當量濃度，分別介於4.41~183.73 pg I-TEQ/g及0.064~0.9 pg I-TEQ/g，混燒SRF有增加衍生飛灰及底渣生成PCDD/Fs的情況且生成情況飛灰高於底渣。因混燒SRF產生灰渣僅占灰渣總量的2.75% ~ 10%，主要灰渣成分仍受燃煤、輪胎衍生燃料(Tire derived fuel, TDF)及石灰石影響，故混燒SRF的飛灰結渣指數及底渣的積灰指數與無使用SRF情況相較，無明顯升高之情況。
蒸汽成本方面，混燒三種SRF都能顯著降低蒸氣成本，使用塑膠、塑膠與紙渣製成的SRF，蒸氣成本下降至無使用SRF情況的65%。本次研究使用的SRF，各SRF製造廠皆無相關品質管控標準及檢測數據，導致同批次的物料外觀及檢測值差異甚大，造成鍋爐混燒SRF的石灰石用量明顯增加，致使混燒SRF的灰渣處理費用及藥劑費用分別相較無混燒SRF情況增加49%及91%。整體而言，後續SRF製造廠的收料與產品的品質管控機制較趨嚴謹，並產出品質穩定的SRF供鍋爐業者使用，將大可降低用藥成本與鍋爐異常操作受損之風險，進而提升SRF後續推廣與應用之發展潛力。;This research investigates using three different sources of Solid Recovered Fuel (SRF)—fiber, plastic, and paper residue—in a fluidized bed boiler for blending tests. The results demonstrate that SRF can be effectively used for boiler fuel charging control, steam output, and temperature regulation, all supporting stable boiler operation. The boiler′s thermal efficiency can exceed 80% with SRF usage. Elemental analyses of the SRFs reveal higher nitrogen and chlorine contents than coal, while the sulfur content is lower. The desulphurization and denitrification systems of the boiler achieve removal efficiencies of over 95% when using SRF, ensuring that emissions of SO2, NOX, and HCl in the stack exhaust meet regulatory standards.
Analysis of fly ash and bottom slag from the SRF-co-fired boiler indicates that the concentrations of metals in the Toxicity Characteristic Leaching Procedure (TCLP) are below 20% of regulatory limits. However, the co-firing of SRF increases the generation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in fly ash and bottom slag, with fly ash showing higher levels than bottom slag. These compounds are known to be highly toxic and persistent in the environment, which raises concerns about the environmental impact of SRF co-firing. The combustion of SRF contributes only 2.75% to 10% of the total ash, with the main composition of the ash still influenced by coal, Tire-Derived Fuel (TDF), and limestone. Consequently, there is no significant increase in the fly ash slagging index and bottom slag accumulation index compared to scenarios without SRF.
From an economic perspective, the co-firing of all three SRF types can lead to significant cost savings in steam production. For instance, the costs for SRFs made from plastic and plastic-plus-paper residues can drop to 65% of those without SRF. This promising aspect of SRF usage is a key point to consider. However, it′s important to note that the SRFs used in this research lack relevant quality control standards and consistent test data from manufacturers, leading to significant variability in material appearance and test values within the same batch. The use of blended SRF in boilers also results in a marked increase in limestone usage, leading to a 49% rise in ash treatment costs and a 91% increase in pharmaceutical costs compared to scenarios without SRF. The study strongly recommends the establishment of a robust quality control mechanism for SRF materials and products by government agencies. This measure is not just important, it′s crucial in ensuring the production of SRFs with consistent and stable quality. This, in turn, can help reduce medication costs for boiler operators and minimize the risk of damage from abnormal boiler operation. The potential impact of this recommendation on the industry underscores the significance of this research. |
