木顆粒為常見的農業廢棄物之一，目前台灣主要的處理方式多以掩埋為主，但台灣土地有限且過度的掩埋會造成環境的破壞問題，而廢塑料則來自於化石燃料，其不易降解，無法使用掩埋方式處理，目前多以焚燒處理為主流，但也衍生出了重金屬、戴奧辛、飛灰等對人體與環境有害的相關問題，因此需以更有效率且對環境更友善的方式來處理。
純氧燃燒(Oxy-Combustion)被認為是目前最有潛力的碳捕捉與封存(CCS)技術之一，相較於其他碳捕捉技術而言，純氧燃燒具有較高的碳捕捉效率，且同時能提高燃燒效率，降低NOx等污染物排放等優點。
本研究主要探討木顆粒與聚乙烯(PE)於流化床的純氧燃燒特性，首先進行燃料特性分析，包括熱值分析、近似分析、元素分析以及利用熱重分析儀探討燃料之受熱行為與計算活化能，並探討其協同效應。最後則將木顆粒與廢塑膠以不同比例混合，利用鼓泡式流體化床進行氧氣/二氧化碳下共燒實驗，實驗參數包括燃料混摻比:0-40%，氧氣濃度:25-%40%，二次氣體(O2)比例:0-30%，探討不同條件下的煙氣氣體成分、濃度以及爐溫分佈曲線，並進行可用能分析。研究結果顯示木顆粒與聚乙烯之協同效應可分為三個階段，分別為240℃-400℃的促進效應、400℃-480℃的抑制效應以及480℃-560℃之促進效應。使用Coats-Redfern數學模型進行活化能分析，燃料整體活化能在70-90 kJ/mol之間，而隨著O2濃度提升，活化能亦顯示出增加的趨勢。在流化床實驗方面，固定燃料混摻比與二次氣體比例的條件下，與空氣條件相比，25%O2/75%CO2條件下將導致流化床較低的密相區溫度，而透過提高氧氣濃度，在30%O2/70%CO2條件下可得到與空氣相近之密相區溫度。O2濃度的增加，使NO排放提升。二次氧氣比例增長爐體內氣體停滯時間，使NO濃度降低。此外，O2濃度的增長，將使CO濃度下降，但於40%O2條件下可能因床材局部燒結反而導致CO的增長。流化床燃燒在無二次氧氣比例時最高可用能發生在25%O2/75%CO2、40%PE時為55.67%，最低則發生在木顆粒空氣燃燒條件下，可用能為24%。可用能隨二次氧氣比例提升而增加，最大可用能發生在30%BR、30%SOR條件下為60.1%，最低可用能發生在30%BR、0%SOR條件下為43.02% 。

This study investigates the oxy-fuel combustion of wood pellets and polyethylene (PE) in a fluidized bed combustor. First, fuel properties were analyzed, and thermal behavior through thermogravimetric analysis (TGA), along with the calculation of activation energy and exploration of synergistic effects. Finally, co-combustion of wood pellets and PE were conducted in a bubbling fluidized bed. The experimental parameters included fuel blending ratios, oxygen concentration, and secondary oxygen ratio. The study examined the composition and concentration of flue gas under different conditions, as well as the furnace temperature distribution, and performed exergy efficiency analysis. The results show that the synergistic effects of wood pellets and polyethylene can be divided into three stages: a promotion effect between 240°C-400°C, an inhibition effect between 400°C-480°C, and a promotion effect between 480°C-560°C. Activation energy analysis revealed that the overall activation energy of the fuel ranged between 70-90 kJ/mol, and increased with the O2 concentration. In the fluidized bed experiments, a temperature in the dense phase zone similar to that of air conditions could be achieved under the 30% O2/70% CO2 condition. The increase in O2 concentration led to higher NO emissions. The increase in the secondary oxygen ratio prolonged the gas residence time within the furnace, which resulted in a decrease in NO concentration. Additionally, the increase in O2 concentration led to a decrease in CO concentration, but under 40% O2 conditions, local sintering of the bed material may instead cause an increase in CO. The highest exergy efficiency in fluidized bed combustion without a secondary oxygen ratio occurred at 25% O2/75% CO2 and 40% PE, reaching 55.67%. Exergy efficiency increased with the secondary oxygen ratio, with the maximum exergy efficiency of 60.1% occurring at 30% BR and 30% SOR conditions.

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