近年來隨著人們對於能源的需求日益高漲，而各國仍以化石燃料為燃料的火力發電為主，進而使得廢氣排放與環境汙染問題不容人們所忽視。純氧燃燒結合煙道氣迴流已驗證為一有效捕獲二氧化碳與減排的技術，本論文的首要工作即是以純氧燃燒結合煙道氣迴流應用技術，深入探討澳洲煤、印尼煤與混合煤(60%印尼煤與40%澳洲煤)在不同供氧量與改變煙道氣迴流量的燃燒特性分析，同時分析兩種煤種與混合煤於空氣燃燒的長時間穩定燃燒特性分析，以及澳洲煤在不同一、二次風流量與供煤量下的燃燒特性分析。本研究發現在空氣燃燒的情形下，混合煤的SO2與CO排放依照線性比例介於澳洲煤與印尼煤之間，而NO的排放呈現非疊加性，低於澳洲煤與印尼煤；在改變不同的一、二次風流量與供煤量的實驗中發現，NO的最高排放濃度伴隨著最低的CO排放濃度，SO2的排放濃度不受一次風流量的影響，減少一次風流量與減少供煤量均可以降低CO排放濃度與其震盪範圍，增加燃燒的穩定性；在純氧燃燒試驗中，澳洲煤在兩種供氧量條件下進行實驗，結果發現，較低供氧量會有較低的O2與NO排放濃度，且與空氣燃燒時相比NO排放濃度可減少74%，但CO、SO2與CO2的排放濃度會較高，其中CO2可穩定維持在94%，最高可達94.8%。研究結果顯示印尼煤的O2排放濃度會隨著煙道氣迴流量的增加而增加，此外，在較低煙道氣迴流量條件下，與澳洲煤相互比較會發現有較高的CO濃度排放；而在較高煙道氣迴流量時，印尼煤的NO濃度排放也會比澳洲煤高，另外CO2 濃度在較低的煙道氣迴流量時可維持在92%。混合煤的SO2與CO的排放濃度趨勢近似於澳洲煤，其中SO2、NO的排放濃度介於澳洲煤與印尼煤之間，而CO2 濃度則能維持在89%～93%之間。

Recently, as the demand on energy has soared, most countries are still relying on fossil fuel-fired power plants for energy generation. However, people should be deeply concerned about the resulting pollutant emissions and their impact on the environment. Oxy-combustion with re-circulated flue gas has been verified as an effective technology to capture carbon dioxide and reduce emissions. The objectives of this thesis are to investigate the combustion characteristics of Australian coal, Indonesian coal and blended coal (60% Indonesian coal and 40% Australian coal) under different oxygen supply rates and flow rates of re-circulated flue gas (RFG) in depth under oxy-combustion in order to analyze two different coals and blended coal combustion characteristics in long-term steady combustion under air-combustion, as well as to study the combustion characteristics of Australian coal under varied primary/ secondary air and coal feed rates. SO2 and CO emissions for blended coal exhibit fixed values according to the prediction of the linear additive law while NO emission for blended coal does not and is lower than the other two under air-combustion. In experiments with varied primary/ secondary air and coal feed rates, the highest NO emission has been shown to accompany the lowest CO emission, and SO2 emission is independent of the flow rate of primary air. Both lower primary air and lower coal feed rates could potentially reduce CO emissions and the fluctuation range of such emissions to in turn increase stability. In experiments under oxy-combustion, Australian coal with a lower oxygen supply rate exhibits lower excess oxygen and NO emission while CO, SO2 and CO2 exhibit higher emissions. Furthermore, the CO2 concentration could maintain at 94%, and the highest value is 94.8%. Moreover, NO emission could be reduced up to 74% compared with air-combustion. In the case of Indonesian coal, the excess oxygen elevates as the flow rate of RFG increases. In addition, Indonesian coal compared to Australian coal has higher CO emissions at a low flow RFG rate, and it also has higher NO emission at a higher RFG flow rate, besides, the CO2 emission could maintain at 92% at low RFG flow rate. The trends of SO2 and CO emissions for blended coal are close to those for Australian coal as well as the SO2 and NO emission range of blended Australian coal and Indonesian coal. Furthermore, the CO2 emission could maintain at 89%~93%

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