一個吸收氣體的平板式濕式分離器

Abstract

本研究設計並開發了一種高效率的平板式濕式固氣分離器（Parallel plate wet denuder, PPWD），以改善現今國內煙道酸性氣體標準採樣方法的缺點，有助於提升採樣分析的方便性及準確性。 本研究之平板式濕式固氣分離器由兩片玻璃平板組成作為酸性氣體之吸收表面。由上而下的吸收液流經平板表面後會形成一層水膜，而氣體在平板間由下往上流動而被吸收。每個平板吸收表面長為150 mmA寬為75 mm，兩平板間隙為4 mm。本研究利用VICI公司滲透管所產生之HF氣體作為測試氣體，滲透速率為109 ng/min±25% ( 30℃)，每個平板的去離子水吸收液流量為1 cc/min，採樣時間為15分鐘，氣體流量為5~10 L/min。氣體由吸收液吸收後，利用IC離子層析儀進行吸收液的樣本濃度分析，並據以計算PPWD的吸收效率。□ 實驗結果顯示若玻璃平板為光滑的平面玻璃，即使經塗敷TiO2再配合UV光照射，形成的水膜仍不均勻，氣體吸收效率因為部分乾掉表面的槽道效應而僅約為25%。若利用多孔玻璃平板塗敷TiO2再經UV光照射，結果發現其表面親水性佳、水膜均勻，.當氣體流量為5L/min、7 L/min和10 L/min時氣體吸收效率分別為105.36%±9.06%、96.76%±1.57% 和90.33%±4.63%，且實驗結果與理論吸收效率相符。

A high-efficiency parallel plate wet denuder (PPWD) was designed and developed in this study in order to improve the present standard sampling method for acidic gases from the stack. It is also helpful to facilitate the sampling method and increases the sampling accuracy. The parallel plate wet denuder is made of two glass plates acting as the active surfaces for acidic gas absorption. The scrubbing water is flowing downward along the surfaces to form water film to absorb the gas flowing upward between the two surfaces. Each glass plate is 150 mm long, 75mm wide and the gap between the two plates is 4 mm. HF gas was generated by the permeation tube (144-653-0050-C30, VICI, Metronics, INC., WA, USA) and used as the test gas with the permeation rate of 109 ng/min ± 25% at 30 degree C. Deionized water was used as the scrubbing liquid at the flow rate of 1 cc/min for each plate and the air flow rate was 5~10 L/min during the 15-minute sampling time. An Ion Chromatograph was used to analyze the samples and determined the collection efficiency of the PPWD. Water film was found to be non-uniform even when TiO2 nanoparticles were coated on the smooth glass plates and the surfaces were irradiated with UV light. The gas absorption efficiency was only about 25% owing to the channeling effect through the partially dried surfaces. If the porous glass plates were coated with TiO2 nanoparticles and irradiated with UV light, super-hydrophilicity was found to be achieved and water film became uniform. When the HF gas flow rate was 5 L/min, 7 L/min and 10 L/min, the gas absorption efficiency was 105.36% ± 9.06%, 96.76% ± 1.57% and 90.33% ± 4.63%, respectively. The experimental data also matched with the theoretical values very well.