揮發性有機物洩漏逸散特性之研究-球閥為例

Characteristics of VOC Fugitive Emission from Ball Valve Leakage

胡偉興(Wei-Hsing Hu)

指導教授 ： 章裕民

國立臺北科技大學/工程學院/工程科技研究所/博士(2014年)

https://doi.org/10.6841/NTUT.2014.00182

摘要

有害揮發性有機物從閥件洩漏逸散到環境的問題已經引起大眾的關注。本研究以圍封吹拂的實驗方法，量測球閥VOCs洩漏濃度、操作條件及環境參數，探討VOCs洩漏逸散的影響因子，並建立球閥的VOCs洩漏排放率、洩漏排放係數及洩漏排放關係式，利用上述三者來推估實場球閥的VOCs洩漏排放量與利用環保署公告排放係數推估排放量相比，更符合實場現況。
研究結果顯示在流動狀態下，VOCs洩漏排放率與「流經該元件之質量流率」及球閥「尺寸」成正比，但與球閥「開度」及「VOCs物種分子量的平方根」成反比；在非流動狀態下，VOCs洩漏排放率與「儲槽物料量」及「VOCs物種擴散係數」成正比。在流經球閥之質量流率1.35~4.05 g/hr，球閥尺寸1/2~2 in.的條件下，實驗室求得的VOCs洩漏排放係數，與實場求得的VOCs洩漏排放係數相比較，兩者誤差範圍在10%以內。VOCs洩漏排放關係式可表示成E=Krα (R2=0.967~0.994)，其中α值會隨著球閥尺寸而略為變化，根據研究結果發現α值等於0.21，K值則會與VOCs種類及VOCs洩漏濃度有關。在信賴水準95%的條件下，利用VOCs洩漏排放關係式去推估VOCs洩漏排放率，誤差範圍在±15%內。然而，VOCs從球閥洩漏逸散的情況在真實的狀況可能更加複雜，若要得到更精準的VOCs洩漏排放推估關係式，則需要後續更多的驗證條件。

關鍵字

球閥 ； 洩漏 ； 揮發性有機物 ； 逸散

並列摘要

Hazardous Volatile Organic Compounds (VOCs) released from industrial valve leakage into the environment have been causing public concern. In this work, a series of experiments were systematically carried out to continuously measure VOCs leakage through ball valve by the blow-through method. According to operating conditions, it can be estimated emission rates, emission factors and correlation equation for ball valve VOCs leakage. These are more accurate to estimate VOCs leakage emissions than Taiwan EPA emission factor.
This paper presents the leakage emission rate of VOCs increase with the VOCs flow rate, valve size and decrease with valve opening, the square root of the VOC molecular weight of the flow system. In non-flow system, the leakage emission rates of VOCs increase with the amount of material and VOCs diffusion coefficient. If we make a comparison between emission factor in laboratory and field, we found the percentage error within 10% error range. The correlation equation was found to be expressed as follows: E=Krα (R2=0.967~0.994). α seems a little increase with an increase of valve size. According to experiment result, we found α is 0.21. K is dependent on volatilisation organic compounds and the ball valve leakage concentration of VOCs. The correlation equation describing the emission rate of ball valve was developed and validated experimentally in this work. There is a statistical error of ±15％ if submitted under 95% probability limits for the correlation. However, the actual VOCs emission mechanism from a ball valve leakage could be more complex out of consideration in this study. More intensive study on other conditions would better verify the results obtained in this paper.

並列關鍵字

Ball Valve ； Leakage ； VOC ； Fugitive

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