利用電弧爐碴以超重力碳酸化程序進行碳捕捉與水泥取代

Abstract

溫室氣體減量為近年全球共同關注的目標，本研究本針對「超重力碳酸化程序進行碳捕捉與水泥取代」，進行電弧爐還原碴碳酸化捕捉二氧化碳及水泥取代績效評估，以電弧爐製程後的鹼性固體廢棄物電弧爐碴，進行於「開發二氧化碳捕獲技術」方面，究指出使用超重力旋轉填充床進行二氧化碳吸附技術為一相當有潛力之技術，超重力電爐渣碳酸化程序最高碳酸化轉換效率約為83%，捕碳容量約為0.382 kg per kg-EAFS；反應後水酸鹼值可降低至 6.3 左右。「溫度」為影響效率之重要操作參數，應從物料供應與環境經濟效益最佳化角度進行選擇。另一方面，反應後產物更添加於水泥砂漿做水泥取代材料，結果顯示水泥中摻入碳酸化反應愈高電爐渣，將顯著減少水泥凝結時間；摻入碳酸化反應愈高電爐渣的較摻入反應前的電弧爐渣強，尤其是在早期抗壓強度（3-day與7-day）及中期（28-day）強度。然而，於本實驗中碳酸化對膨脹穩定性效果並不顯著。此外本研究亦提出對於新一代超重力程序設備設計建議及整體碳足跡評估。

In this study, CO2 capture experiments were conducted by accelerated carbonation in a rotating packed bed (RPB). EAF slag was selected as feedstock in this research due to its high calcium content and high CO2 capture capacity. In term of sustainability, the carbonated EAFS can be regarded as not a waste but a resource. On the other hand, many studies have been conducted on the use of slags as supplementary cementitious materials. The predicted optimal conversion which was determined by response surface methodology was 83.7% is corresponding to a capacity of 0.382 kg CO2 per kg EAFS. In the cement replacement experiments, the results reveal that the HiGCarb process appears to accelerate the hydration of the silicates to form a C–S–H-like gel and calcite which can enhance the performance of blended cement with EAF Slag. It has a particular influence of cement replaced by fresh EAFS on the setting time. The strength of cement replaced by carbonated EAFS was higher than the cement replaced by fresh EAFS in all curing age. The performance of blended cement with different kind of supplementary cementitious materials (EAFS、BOFS、FA) was also compared in this study. In addition, the concept of new generation HiGCarb process was proposed. To construct a complete production chain, the automatic control system should be established.