| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程研究所 === 99 === Silane is a specialty gas commonly used in the semiconductor, TFT-LCD, and photovoltaic industries. It is also a pyrophoric gas which normally ignites upon in contact with air, but the ignition behavior of pure silane release into air has been known to be effected by various parameters such as release size, release velocity, and temperature. In a confined space with gas accumulation, the pop can lead to a gas explosion to bring about significant damage. Therefore, the major potential hazard of silane is not in its pyrophoricity but in its unpredictable ignition behavior.
This study aimed at steady release of pure silane. The vent stub of silane was located in the stainless steel chamber to control ambient moisture. Another part was to study the effects of temperature on the silane release under extreme low moisture condition of less than 40 ppmv. High speed video camera was used to record the instance of delayed or prompt ignition.
Experimental results show that the critical velocity for delayed/prompt ignition increases with decreasing moisture confirming that the moisture played an inhibitory role on the silane ignition in air. The critical moisture content occurs at 2,565 ppmv～16,794 ppmv. In the tests with simultaneously controlling the moisture in the air and controlling pure silane temperature, the critical velocity was found to increase with increasing temperature at extreme low moisture condition. Assuming Arrhenius law applies, the logarithm of critical exit velocity was found to proportional to the inverse of silane temperature. The activation energy of pure sliane in air without the interference from moisture is determined to be 6.26 kcal/mol which is far lower than that in air. Thus, the moisture is again found to have a strong effects on the silane ignition behavior in air.
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