利用RPB技術進行二氧化碳減量之綜效分析—以半導體業為例

Abstract

本研究於超重力旋轉填充床(Rotating Packed Bed, RPB)中，利用多股來自半導體業所排放之廢水進行二氧化碳捕捉實驗，並透過添加來自鋼鐵業之爐渣提高捕捉二氧化碳效能，以及藉由盤查半導體產業內二氧化碳排放源，建立半導體產業內揮發性有機物(Volatile Organic Compounds, VOCs)控制情境，並搭配不同操作條件下之二氧化碳捕捉表現進行生命週期評估(Life-cycle Assessment, LCA)，以瞭解透過超重力旋轉填充床技術進行之二氧化碳捕捉程序之綜效表現。本研究中探討不同操作條件及不同操作流程對於碳酸化反應之影響，包含不同氣液比、轉速、水質及直接碳酸化或間接碳酸化對碳捕捉能力的影響。本研究發現當氣液比較低時會有較佳的碳捕捉表現；旋轉填充床轉速並非為影響碳捕捉表現之關鍵因素，惟當轉速越高時，其所需的能耗將會越高而增加對環境的影響；而在水質方面，鹼性及富含鈣離子的廢水是較為有利的，因此透過添加鋼鐵業之爐渣於廢水中，使爐渣所富含的大量鹼性物質於廢水中釋放，將明顯提升碳捕捉效能，至多可捕捉13.44g CO2/L，且每公克的爐渣可額外捕捉約0.17公克之二氧化碳。而有關碳捕捉各情境之綜效分析，爐渣的添加不僅提高了碳捕捉效能，也能避免較高的爐渣處理費用，於經濟觀點具有優勢，因此在旋轉填充床及蓄熱式焚化爐(Regenerative Thermal Oxidizer, RTO)系統對VOCs之控制情境下，搭配鹼性離子交換樹脂鹼性廢水添加爐渣進行碳捕捉會有最佳的表現。

This study aims to develop high-gravity rotating packed bed (RPB) technology for CO2 reduction by various streams of wastewater in the semi-conductor industry. To enhance the effectiveness of CO2 capture, the slag from steelmaking industry is introduced. The effects of different operating condition and modes such as different G/L ratio, rotating speed, water quality, and direct or indirect carbonation on carbonation process would also be investigated. The research work shows that better performance for CO2 capture would be occurred when G/L ratio is lower. Besides, the rotating speed isn’t the key factor affecting CO2 capture performance. Nonetheless, the higher the rotating speed is, the more energy consumption and the environmental impacts would be. For water quality, alkaline and calcium ion-rich wastewater is more advantageous. Adding steelmaking slag to the wastewater, a large amount of alkaline substances would be released, which would significantly improve the CO2 capture performance. The most amount of CO2 capture is 13.44 g CO2/L, and an additional 0.17 grams of CO2 could be captured per gram of steelmaking slag. In addition, the inventory of CO2 emission sources in semi-conductor industry is conducted to establish the systems of volatile organic compounds (VOCs) control. Life cycle assessment (LCA) is carried out with the performance of CO2 capture under different operating conditions to understand the performance of CO2 reduction via RPB. For comprehensive performance evaluation, adding steelmaking slag could improve the effectiveness of CO2 capture, avoid the expense of slag treatment, and be advantageous in economic aspect. As a result, with VOCs control via RPB and regenerative thermal oxidizer (RTO) system, wastewater A with slag addition has the best CO2 capture performance.