以介電質電漿反應器去除氣流中苯乙烯之研究

Abstract

苯乙烯為常見之揮發性有機物，易於化工程序中排放，然而又屬於環境賀爾蒙類的有害物質，可能會導致生物突變與致癌。因此對其逸散必需有效加以控制。本研究利用非熱電漿技術中的介電質反應系統對苯乙烯進行分解效能之探討。實驗以管線型與填充型兩種介電質反應器作為探討重點。 在管線型反應器中，將探討反應器設計尺寸，包括有放電電極直徑、反應管內徑與介電質厚度，對操作效能與放電後所產生副產物之影響。實驗並比較在空氣和氮氣下操作，以及苯乙烯進流濃度對去除效率之影響。而在填充床型反應器的實驗中，將比較玻璃珠、Al2O3和Pt-Pd/Al2O3等三種填充介質對處理效能之影響。此外，本研究特別將苯乙烯分解過程中，苯乙烯、固相有機副產物、氣相有機副產物、CO與CO2等五大類含碳物質，隨操作條件之變化與分佈清楚呈現。 實驗結果顯示在相同施加電壓、電功率與單位能量密度作為操作指標時，皆以使用粗放電電極直徑、細管內徑與薄的管壁的反應管可以得到較高分解效能。但結果另呈現使用管線型反應器將苯乙烯氧化成CO2最佳轉化率只有31%，表示無法有效將分解之有機物完全氧化成CO2，當以玻璃珠填充床操作時，最佳CO2轉化率可提升至61%，而以Pt-Pd/Al2O3填充，則最佳CO2轉化率可提升至96%，並可有效抑制副產物O3、N2O和CO的生成。

In this study the effect of some geometric parameter on the performance of wire-tube dielectric barrier discharge reactor at different operation indexes were evaluated experimentally. The geometric design parameters included discharge wire diameter, discharge gap distance and thickness of dielectric materials. And the operation indexes considered were the applied voltage (kV), output power (W), specific energy density (J/L) and output current (A). The results showed that the styrene destruction efficiency is increased with an increase in the discharge wire diameter and decreases in the discharge gap distance and thickness of dielectric materials under the same applied voltage, output power and specific energy density. But the same styrene destruction efficiency is observed under the same output current even the geometric design parameters are different. Furthermore styrene wase treated using dielectric barrier discharge reactors packed with different materials of glass, Al2O3 and Pt-Pd/Al2O3. With packing bed dielectric discharge reactor the styrene destruction efficiency was improved greatly. The main effect of packed bed reactor by the introduction of a catalytically active material of Pt-Pd/Al2O3 was a higher selsctivity of CO2. In addition, O3, CO and N2O generated from the dielectric barrier discharge reactors packed were significantly decrease with Pt-Pd/Al2O3.