以追蹤氣體評估氣罩捕集效率之探討

The study of capture efficiency for local ventilation hoods with trace gas

鄭凱駿(KAI-CHUN CHENG)

指導教授 ： 張振平

長榮大學/健康科學學院/職業安全與衛生學系(所)/碩士(2015年)

https://doi.org/10.6833/CJCU.2015.00045

摘要

通風櫃的功能是將櫃外乾淨的空氣導入，讓櫃內的汙染物限制住，再經通風櫃的排氣導管抽出。目前測試通風櫃的方法如:EN14175-3:2003、ASHRAE110中的追蹤氣體測試，由於測試用的追蹤氣體為SF6(六氟化硫) ，且需要長時間釋放才能評估通風櫃的捕集率，而全球暖化潛勢(GWP)高達二氧化碳的22800倍，所以有必要測試新的方法減少追蹤氣體(Trace gas)SF6的使用量，並快速評估通風櫃的效能。本研究目的是1.建立以 SF6為追蹤氣體的通風櫃性能檢測方式。2.建立風管處測量濃度來推算總捕集效率的評估方法。3.測量通風櫃開口面速度，觀察其表面風速與氣流之相關性。4.使用歐洲的測試方法(EN14175)來測試其控制效能，氣簾式通風櫃(下吹上吸式)、傳統式通風櫃的測試結果與總捕集率間之關係。
依據上述原則，實驗使用EN14175-3:2003中的追蹤氣體靜態濃度測試，此方法先設定通風櫃的測定點，然後在不同比例的混合氣體為2L/min等速率釋放，並將網格狀的採樣探頭放置在不同的測定點的通風櫃面上，觀察其濃度分布。在同樣的條件下再把採樣探頭放置風管中心處偵測其濃度與櫃面洩漏進行分析。而分析儀器是使用攜帶式紅外光譜儀(InfraRan) ，儀器抽氣後會經由密閉腔(Close Cell)進行濃度的分析。傳統式通風櫃與氣簾式通風櫃依照方法使用SF6作為追蹤氣體，各測3次，測試所得到結果顯示，其櫃面洩漏濃度越高2種方法有相關性越高。總捕集率法雖不太靈敏，但可嘗試用來大量評估通風櫃性能，，相對於EN14175-3:2003是一種價廉且快速的通風櫃性能評估方法，可花費更少的時間與成本。

關鍵字

追蹤氣體 ； 化學式通風櫃 ； 氣簾式通風櫃 ； EN14175 ； 捕集效率

並列摘要

The major effort of fume hood is that locked the contaminants in the cabinet, and pushed it out through the exhaust duct. Currently common testing methods for the fume hood performance are trace gas methods, such as: EN14175-3: 2003, ASHRAE110, because the methods used SF6 as the trace gas, it takes a long time to evaluate the leakage of the fume hood, and release lots of trace gas. The global warming potential (GWP) of SF6 is up to 22,800 times higher than CO2, So we have to find new ways to reduce the release amount of tracer gas SF6, and the rapid way to elevate the performance of the fume hood.
The purposes of this study are 1. Establish a evaluate method of fume hood performance with SF6 as trace gas. 2. Establish a evaluate method of estimate the total capture efficiency from the duct’s concentration. 3. Measure the fume hood face velocity and find the correlation of the air flow pattern with face velocity. 4. Use of the European test method (EN14175) and total capture efficiency to evaluate the performance of the 2 different type fume hoods (traditional and air curtain type) , and find out the relationship of 2 methods.
According to the above principles, this study using EN14175-3: 2003 tracer gas (Trace Gas Measurement) static mode as one of the test method, this method to set the 6 measurement points of the fume hood open face, and then release the mixed gas with 1/10 SF6 of 2L / min flow rate, and grid-like surface of the sampling probe is placed in the setup measurement points, observe the concentration distribution. Under the same conditions, the sampling probe is placed at the center of the duct to measure the concentration and to estimate the capture efficiency. The measurement instrument is the portable infrared spectrometer (InfraRan), the concentration will be analyzed through the enclosed chamber (Close Cell) from the probe.
Traditional fume hood and air curtain fume hood in accordance with the method using SF6 as a tracer gas, each data measured three times, test results showed that the higher the concentration of its counter leakage is more likely to be relevant.
Although this new method is not very sensitive, but it is an inexpensive and fast fume hood performance evaluation method, which can spend less time and cost than EN14175method.

並列關鍵字

trace gas ； chemical hood ； EN14175 ； capture efficient

參考文獻

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