經由旋轉填充床進行碳捕捉再利用與空氣污染物排放減量

Abstract

本研究專注於利用整合式超重力旋轉床技術應用於二氧化碳捕捉再利用與空氣汙染物之去除，本研究使用鹼性廢棄物作為吸收材料，同時對鹼性廢棄物進行改質再利用。超重力碳酸化過程具有反應時間短並且操作溫度、壓力條件相對低的特點，在模廠設備實驗中可同時去除煙氣中二氧化碳、氮氧化物、細懸浮微粒。碳捕捉所用材料電弧爐還原渣富含有大量鹼性成分，通過碳捕捉程式之改質作用，可部份取代波特蘭水泥成分。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：研究不同轉速和液固比操作及溶劑條件下，通過直接碳酸化及間接碳酸化流程，比較得到各參數對於碳捕捉能力之影響。研究發現，旋轉填充床轉速的提高可大幅加快反應進程，提高碳酸化程度。探究浸出及碳酸化過程中涉及之化學反應及質傳動力學：研究運用縮核模型及整體反應模型對電弧爐渣之浸出過程進行了描述，模型之間的比較得到，膜擴散與化學反應作用為電弧爐渣浸出之主要控制步驟，整體反應模型在擬合過程中也得到了比較好的相關性。

This study aims to develop high-gravity technologies for carbon capture utilization and air pollutant reduction by alkaline waste by-products. High gravity technology using in carbon capture process have advantages of high mass transfer coefficient, operating in atmospheric pressure and ambient temperature, small space requirements. In the on-site experiments, high gravity technology applied to reduce CO2, NOx, SOx and particle matters simultaneously. In addition, the electric arc furnace slag (EAFS) used in carbon capture process can be reused to substitute Portland cement after stabilization. The research objectives included investigating the effects of operating conditions on the carbonization behavior of rotating packed bed (RPB): The effect of two operation parameters including rotating speed and liquid-to-solid ratio on the carbon capture capacity of EAFS were investigated for both direct and indirect carbonation processes. The results showed that rotating speed of RPB can increase reaction rate and the carbonation efficiency significantly. Several models are developed to describe the reaction kinetics and mass transfer, during the leaching and carbonation process. A shrinking core model was used to describe the leaching process of alkaline waste. process of alkaline waste. The comparison results among models showed that the process was mainly controlled by fill diffusion effect. In the carbonation process, a surface coverage model was used for the description of calcium conversion and a calcium concentration model was used for the prediction of calcium concentration in solution; the performance of high gravity technology was demonstrated on air emission control via on-site experiments: The feasibility to use stabilized electric arc furnace slag for substituting Portland cement in making concreate was investigated: Fresh EAFS and carbonated EAFS are all feasible for Portland cement substitution according to their similar constitutions with ordinary Portland cement (OPC). Besides, to ensure the safety of using such substitution materials, the process must proceed by the TCLP test. The performance test in workability, durability and compressive strength shows that carbonated EAFS has a better performance comparing with other materials. Besides, a comprehensively evaluation of the process from the perspective of environmental, economic and engineering aspects. The following optimized operation conditions were obtained by the 3E (environmental, economic and engineering) analysis for the on-site operation.