雙極充電對次微米微粒膠結效率影響之研究

Effect of operating parameters on submicron particle agglomeration by bipolar charging system

詹聖凱(Sheng-Kai Chan)

指導教授 ： 林文印

國立臺北科技大學/工程學院/環境工程與管理研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00685

摘要

靜電膠結技術是一種利用電能讓微粒產生移動，並且在移動的過程中與其他微粒碰撞而膠結在一起的技術。膠結後微粒之數目濃度會降低，粒徑大小會增加。靜電膠結之操作步驟為：1.微粒經由兩種不同極性的電暈充電器來帶電。2.利用交流電場讓微粒移動，導致微粒與微粒相互碰撞而膠結。然而，過去的研究對於次微米微粒的膠結效率仍有待改善，因此本研究將設置一套靜電膠結系統，探討實驗系統的操作參數對次微米微粒膠結效率的影響。
研究結果顯示，微粒數目中位數粒徑、數目平均數粒徑及數目幾何平均粒徑均隨著充電區的操作電壓增加或膠結區交流電的操作電壓增加或微粒在膠結區的停留時間增加而增加。於雙極充電電壓分別為+7.5kV、-6.6kV與停留時間4.5秒下，當交流電電壓從16kV增加到21kV，次微米微粒膠結效率從12.2%%增加到15.8%。於雙極充電電壓分別為+7.5kV、-6.6kV與交流電操作電壓21kV下，當停留時間從2.25秒增加到4.5秒時，次微米微粒膠結效率從11.2%增加到15.8%。臭氧產生量的部分，主要受到電暈放電產生之電流所影響，充電的電流在0.01mA與0.02mA時臭氧濃度分別約為 100 ppb與200 ppb。對於膠結區交流電產生的臭氧遠低於充電區直流電產生的臭氧。

關鍵字

次微米微粒 ； 靜電膠結 ； 帶電微粒

並列摘要

Electrostatic agglomeration is a technique which can let the particle agglomeration. Particles move and collide with each other as electric field is provided. The small particles are growing into a large one and the particle number concentration is decreased when particles agglomerate. The mechanisms of the electrostatic agglomeration include: (1) Particles are charged by two different polar corona chargers. (2) These particles oscillate in an alternating electric field, and then particle collide with each other. However, the agglomeration efficiency of submicron particle is not good as well. Therefore, an electrostatic agglomeration system was set up in this study. The objective of this research was to find out effect of operating parameters on submicron particle agglomeration by electrostatic agglomeration system.
The experimental results indicated that count median diameter, count mean diameter and geometric mean diameter were increased as increasing bipolar charging voltage, alternating voltage, and agglomeration residence time. The submicron particle agglomeration efficiency was 12.2% and 15.8% for 16 and 21kV of alternating voltage, respectively, when residence time was 4.5 seconds and bipolar charging voltage was 7.5kV and -6.6kV, respectively. The submicron particle agglomeration efficiency was 11.2% and 15.8% for 2.25 and 4.5 seconds of residence time, respectively, when alternating voltage was 21kV and bipolar charging voltage was 7.5kV and -6.6kV, respectively.
The ozone concentration was 100 ppb and 200 ppb as direct current of charger was 0.01mA and 0.02mA, respectively. The results indicated the formation of ozone concentration was caused by the current of charger. The yield of ozone concentration under alternating current of agglomeration was far less than direct current of charger.

並列關鍵字

Submicron particle ； Agglomeration ； Particle charge

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