油性氣膠評估與控制

本研究開發出一新型旋轉過濾器 (rotation filtration device, RFD)以裝設多孔性濾材，並仿效旋風分離器（cyclone）的旋轉方式進行過濾結果評估。實驗建置測試系統，選擇玉米油（corn oil）和酒石酸鉀鈉（potassium sodium tartrate tetrahydrate, PST）作為挑戰氣懸微粒，以注射式幫浦（syringe pump）輸送溶液再經由超音波霧化噴嘴（ultrasonic atomizing nozzle）以及使用卡里遜霧化器（Collison nebulizer）兩種方式產生挑戰氣膠；再以氣動微粒分徑器（aerodynamic particle sizer, APS）和Fidas® Frog進行微粒之量測，並以之評估油性氣膠的收集效率。結果顯示，挑戰氣膠為液態玉米油微粒時，在0 rpm和9000 rpm旋轉速度、海綿厚度80 mm、孔隙度80 ppi及配合抽氣表面風速13.5 cm/s的旋轉過濾下，RFD之50%截取粒徑分別為1.65 µm和1.02 µm。在本實驗條件下，濾材厚度增加後的RFD採樣截取粒徑從1.62 µm下降至1.02 µm；而濾材孔隙度越密集的截取粒徑從1.26 µm下降至0.96 µm；表面風速提高後的截取粒徑從1.02 µm下降至0.76 µm，而以上實驗之RFD採樣截取粒徑變化都具有統計顯著差異（P<0.05）。液態玉米油微粒和固態PST微粒在單獨或同時產生之三種情況下，在轉速9000 rpm、海綿厚度80 mm、孔隙度80 ppi及表面風速13.5 cm/s的旋轉過濾下，RFD採樣之50%截取粒徑分別為1.03 µm、1.02 µm、0.99 µm。另外，在單獨或同時產生液態玉米油微粒及固態兩種微粒情況下，在本實驗最佳實驗條件時，轉速9000 rpm、厚度68 mm、孔隙度94 ppi及配合抽氣表面風速108.3 cm/s下，經過兩小時負載後，RFD對於氣膠粒徑大於0.45 µm以上有較好的去除效率。 本研究實驗條件下，增加多孔性濾材厚度、表面風速及孔隙度，RFD對微粒收集效率都有顯著提高；而增加旋轉速度後RFD有更好的收集效率。未來對於RFD採樣之操作變項仍需更進一步探討。

This study conducted assessment for sampling result by using the new development rotation filtration device (RFD) filled with porous media filters integrating the method of cyclone centrifugal spins. The testing system established for the experiment used corn oil and potassium sodium tartrate tetrahydrate（PST）as challenge aerosols, and were produced by using an Ultrasonic Atomizing Nozzle, a Syringe Pump and a Collison nebulizer. The collection efficiency of RFD for oil aerosol was assessed by using an Aerodynamic Particle Sizer （APS）and a Fidas® Frog.The results of RFD for the liquid particles condition indicated the cutoff size was 1.65 µm and 1.02 µm for rotation of 0 rpm and 9000 rpm, respectively, under a 80 ppi（pores per inch）foam with thickness of 80 mm, and sampling velocity of 13.5 cm/s. As the experiment increased the foam thickness of RFD, the cutoff size reduced from 1.62 µm to 1.02 µm. However, when increased the foam porosity of RFD, the cutoff size reduced from 1.26 µm to 0.96 µm. Moreover, as increased the sampling velocity of RFD, the cutoff size reduced from 1.02 µm to 0.76 µm. These discrepancies of above cutoff sizes of RFD all had statistical significant (P<0.05).The cutoff size of RFD for three experimental conditions of generated liquid oil particles, solid PST particles or both liquid oil & solid PST particles was 1.03 µm, 1.02 µm, or 0.99 µm, respectively, under a 80 ppi foam with thickness of 80 mm, rotation of 9000 rpm, and sampling velocity of 13.5 cm/s. In addition, under the best condition of the experiment, two hours of sampling loading, the RFD had better collection efficiency for particle diameter greater than 0.45 µm, under a 94 ppi nickel mesh with thickness of 68 mm, rotation of 9000 rpm, and sampling velocity of 108.3 cm/s.The experiment concluded that increased the thickness of porous media, face velocity, and porosity of porous media of RFD could increase the collection efficiency of porous media for sampling oil particles. Moreover, increased the rotation speed of RFD also increased the collection efficiency for sampling oil particles. Further investigation is required for those above operation parameters for RFD in this study in the future.