- 學位論文
金屬氣相合成法備製奈米銀觸媒去除丙酮之研究
Investigation of Removal of Acetone Vapor by Nano-silver Catalyst Produced by Metal Vapor Synthesis Method
摘要
丙酮為光電業與半導體業製程中常用之有機溶劑，當蒸發逸散至空氣中並經由呼吸進入人體，對於健康危害甚巨。傳統上，揮發性有機化合物(volatile organic compounds, VOCs)多以高溫焚化處理，雖然處理效率高，但須添加輔助燃料以維持高溫。是故，若能以反應溫度較低之觸媒焚化法取代，在國際油價日昇的狀況，將可省下可觀之費用。 本研究先以高溫爐將爐管內之銀粉熔融，加溫超過銀的熔點（962 ℃）以產生銀蒸氣並通以氮氣將其攜出爐管，待銀蒸氣離開加溫區後迅速冷凝成銀微粒，再選擇使銀微粒經過（或不經過）微分式移動度分析儀 (differential mobility analyzer, DMA)篩選特定粒徑之銀微粒，並使銀微粒(10、40與60 nm)經過斷面為網格狀之陶瓷載體，奈米銀微粒因擴散與慣性衝擊等機制沉積附著於載體上，再將附有奈米銀微粒之陶瓷載體送入500 ℃爐內煅燒2小時，以求固定微粒之效。 測試階段將前述之陶瓷載體通入丙酮蒸氣（濃度6118 ± 275 ppm），藉由總碳氫化合物分析儀(THC)量測陶瓷載體的上下游之丙酮蒸氣濃度以決定該粒徑銀微粒之觸媒效率。由實驗結果可知，相較於未過篩的銀微粒（Polydisperse），經DMA過篩後的銀微粒（Monodisperse）具有較高的單位質量與單位面積之觸媒轉化效率。 觸媒轉化後的尾氣成份以GC/MS分析，包含乙醛（Acetaldehyde）、 亞甲基丙酮（3-Buten-2-one）、二甲基呋喃（2-methyl-furan）氧化未完全之中間產物，若增加反應時間，最終仍可達完全氧化。
並列摘要
The semiconductor industry demands a large amount of organic solvents which are harmful not only to the workers in the factory but also to the environment. Acetone is one of the common organic solvents for the semiconductor industry. The usual treatment of volatile organic compounds, VOCs, which are the products after evaporating of the organic solvents, is incineration. Replacing higher temperature incineration with lower temperature catalytic incineration can save amazing cost in fuel. The effect of catalyst to decompose VOCs rises enormously when the catalyst size shrinks to nano scale, which causes the increasing of reaction rate and decrease the requirement of high temperature. In this study, the results showed that the nano-silver suspended in nitrogen gas and then inertially impacted on ceramic carrier can be one of the possible ways to apply catalyst. The nano-silver was produced by metal vapor synthesis method with condensation type aerosol generator of electrically heated ceramic tube. The removal efficiency of nano-silver catalyst (10, 40, 60 nm) was tested with inlet acetone concentration 6118 ± 275 ppm at 250, 350, and, 450 ℃. The removal efficiency of nano-silver catalyst showed that monodispersed catalyst caused higher removal efficiency per mass unit or per aera unit than polydispersed one. Acetaldehyde, 3-Buten-2-one, and 2-methyl-furan were identified in the outlet gas by GC/MS. These intermediaries will be totally oxidized if their duration of reaction increases.