- 學位論文
整合式超重力程序於煙氣淨化與副產石灰再利用
Development of High Gravity Process for Integrating Carbon Capture and Utilization with Flue Gas Purification
摘要
本研究重點在於開發整合式的超重力技術，以同時應對二氧化碳減量、空氣污染防治和鹼性廢棄物處置再利用。副產石灰因其富含大量氧化鈣，因此可以當作二氧化碳捕捉的理想材料。本研究目的包括：（1）探究超重力旋轉填充床內碳酸化反應進程；（2）研究不同操作條件對於碳酸化反應之影響；（3）驗證超重力技術對於煙道氣淨化之效果；（4）驗證副產石灰用作輔助性凝膠材料之可行性；（5）從環境、經濟和工程三個面向評估超重力技術之效能。 • 探究超重力旋轉填充床內碳酸化反應進程 借助於電感耦合等離子體分管光度計和熱重分析手段，可以瞭解溶液中鈣離子濃度和固體中氧化鈣之轉化率。隨著反應進行，固體中氧化峰的轉化率逐漸上升，並達到最大值。該現象通過表面覆蓋模式（surface coverage model, SCM）予以描述。此外，通過合理的假設，描述水中溶氧濃度隨BOD分解的Streeter-Phelps方程式被用於描述和預測溶液中鈣離子濃度變化，並得到不錯的相關性。借助於數學模式，研究發現冷卻廢水會抑制碳酸鈣沉澱。 • 研究不同操作條件對於碳酸化反應之影響 研究研究反應溫度、轉速和液固比對於碳酸化反應的影響。研究發現溫度和轉速對於碳酸化有顯著的影響。另外，液固比在冷卻廢水中對碳酸化的影響更為顯著。 • 驗證超重力技術對於煙道氣淨化之效果 通過建立模廠設備，超重力設備被證明可有效去煙道氣中污染物。其中，二氧化碳最高去除率可達95.59%，每日最大捕捉量接近600公斤。通過注入臭氧，超重力技術可有效去除氮氧化物。超重力設備建立後，每年可避免超過8000元美金的費用。 • 驗證副產石灰用作輔助性凝膠材料之可行性 本研究中，副產石灰被用作輔助性凝膠材料。根據測試結果，隨著取代率上升，水泥熟料中的矽酸鹽含量逐漸下降。然而，碳酸鈣可提高水化速率，進而改善水泥性質。最終5%的取代率有利於提高經濟效益和水泥性能。 • 從環境、經濟和工程三個面向評估超重力技術之效能 通過3E分析，超重力技術可有效降低環境衝擊，特別是溫室效應和環境毒性。隨著氣量的提高，二氧化碳捕捉量得到提高，因而其能效亦有提升。借助於圖解法，超重力系統每日二氧化碳捕捉量可達600公斤。捕捉每噸二氧化碳耗能約15度。此外，處理每噸副產石灰可獲得約40元美金。證明超重力設備之較高的經濟效益。
並列摘要
This study was focused on the development of an innovative integrated high gravity (HiGee) system to deal with carbon capture, air pollution control coupled with alkaline waste treatment. Byproduct lime originated from burnt petroleum coke of circular fluidized bed was used as the reacting agent for carbonation. The research objectives included (1) to investigate the carbonation behavior in rotating packed bed (RPB); (2).to examine the effect of operating conditions on carbonation behavior in RPB; (3) to study the conjunction effect of RPB on air pollution control; (4) to inspect the alteration of properties of cement induced by the introduction of byproduct lime; (5) to comprehensively evaluate the process from the perspective of environmental, economic and engineering aspects. • To investigate the carbonation behavior in RPB The concentration of calcium in slurry and carbonation conversion of byproduct lime was examined by Inductively Coupled Plasma (ICP-OES) and thermal gravimetric analysis (TGA) respectively. The correlation between carbon conversion and time was interpreted and predicted by surface coverage model (SCM). On the hand, a Streeter-Phelps equation liked formula was developed and introduced to describe the variation of calcium concentration in slurry, which has achieved good agreement. From the results of modeling, it was found blowdown wastewater was not favorable for carbonation because the precipitation may be inhibited so that the captured carbon dioxide could not be attached into solid matrix permanently. • To examine the effect of operating conditions on carbonation behavior in RPB Rotating speed, solid-liquid ratio and temperature were chosen to examine the influence on carbonation performance. The results indicated that temperature and rotating speed could exert significant influence on carbonation in tap water. In addition, the effect of solid to liquid ratio was more remarkable for carbonation in blowdown wastewater. • To study the conjunction effect of RPB on air pollution control According to the results of on-site operation in real plant, it was proved that the HiGCarb process is effective and efficient for carbon capture and air pollutant removal. Specifically, the highest removal efficiency could reach up to 95.59%, while the maximum daily capture capacity was nearly 600 kg-CO2/day. With the help of ozone, nitric oxide was successfully oxidized as well as absorbed successfully by slurry. In addition, due to the congenital complex packing structure, the particulate matter in flue gas could be efficiently filtrated and collected. After the installation of HiGCarb system, more than 8000 USD of air pollution penalty could be conserved each year. • To inspect the alteration of properties of cement induced by the introduction of byproduct lime Carbonation is able to transform calcium oxide into calcium carbonate. During this research, both fresh and carbonated byproduct lime was introduced into clinker for substitution. According to the results, with substitution ratio going up, the content of silica decreased which is not favorable for cement deployment. However, calcium carbonate was found to be able to accelerate hydration reaction, resulting in more remarkable strength compared with other specimens at the same curing age. Finally, the substitution ratio at 5% was favorable for both economic benefit and engineering performance. • To comprehensively evaluate the process from the perspective of environmental, economic and engineering aspects In order to evaluate the positive effects and negative impacts from HiGCarb process, 3E analysis was performed. It was found that the introduction of HiGCarb process could drastically reduce negative impact to environment, especially global warming potential and toxicity to ecosystem. With gas flow rate going up, the capture capacity increased, and the process would become more energy efficient. Such phenomenon would be beneficial to economic and environmental aspects. Because at higher gas flow rates, less energy would be consumed for capturing one unit of carbon dioxide, which means less pollutant would be generated. According to the results of graphical solution, the highest achievable amount of daily capture capacity is nearly 600 kg-CO2/day. That could be reached at the acceleration of 63 m/s2, corresponding to the energy consumption of 15 kWh/t-CO2. In addition, the economic benefit is also incredible. It is estimated that around 40 USD could be earned by treating one ton of byproduct lime. Finally, the best scenario is determined where the gas flow rate is 1.84 m3/min and rotating speed is 550 rpm.