高爐是目前主要的煉鐵製程，但燒結及煉焦工廠的汙染處理成本逐年提高，故許多鋼鐵廠致力於開發新型的綠色煉鐵製程，以期能擺脫對燒結礦、焦碳等原料限制並減少污染。

高料層煉鐵製程屬煤基直接還原法，此法為將鐵礦與煤礦混合造粒製成煤鐵礦複合球團後，在高溫下進行碳熱還原反應(Carbothermic Reduction)，使鐵礦還原成高金屬化率之直接還原鐵(Direct Reduced Iron, DRI)。除了煤礦中的固態碳可作為主要的還原劑外，煤礦的揮發份(Volatile Matter, VM)亦會在高溫下釋出，其主要成分為碳氫化合物，經高溫裂解後可生成氫氣並幫助球團還原，然而隨著升溫歷程及煤礦VM含量的不同，VM釋出的情況會有所改變，對球團還原也會有影響。

為了探討煤礦揮發份對碳熱還原反應的影響，本研究使用氣體分析儀量測在探討不同升溫歷程下揮發份分解情形（即觀測乾餾煤礦的產氣），有別於中斷實驗的化學分析，氣體分析可提供連續且即時的球團還原情形，且可區隔出煤礦中的VM與碳對球團還原的幫助，VM對球團還原的幫助即是利用球團的產氣減去煤礦乾餾的產氣後定量所得。

實驗結果中顯示，隨著煤礦VM含量與升溫速率的提升，愈多H2能有效地釋出並幫助球團還原，在較快的升溫速率下，煤礦中VM釋出與碳氫化合物裂解的溫度與時間點較接近，讓碳氫化合物成功裂解成H2並幫助球團還原，避免VM在低於碳氫化合物開始裂解的溫度下釋出後被直接吹離球團，而不能裂解成H2，而從煤礦乾餾的數據也可知，在較快的升溫速率下，煤礦會釋出較多的CH4以及H2。

Blast furnace is the main ironmaking process now, but owing to the pollution from sintering and coking process, a variety of eco-friendly ironmaking process are actively researching and developing. Among them, carbothermic reduction of iron ore/coal composite pellets is considered to have potential for reducing greenhouse gas emission.
The main reductant for carbothermic reduction is carbon, but the volatile matter in the coal will also help the reduction of iron oxide. The main components of volatile matter are hydrocarbons, which will crack and release the reductant - hydrogen during the carbothermic reduction.
In this study, we focus on the effect of the volatile matter on the reduction of the iron ore-coal composite pellets under three kinds of heating rate. By using gas analyzer, which can provide us instant and continuous data about the pellet, we could quantify the reduction degree of the pellets. Besides that, to confirm the credibility of gas analysis, we interrupt the carbothermic experiement with different temperature and then send the reduced pellets to do the chemical analysis.
The result shows that with the increase of volatile content in coal and heating rate, more H2 can be released and reduce the pellets. At faster heating rate, the temperature and time of VM released and hydrocarbon crack are closer, so the hydrocarbons can successfully crack into H2 rather than blown away from pelles directly without cracking.

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