矽甲烷為半導體、平面顯示器及太陽能電池三大產業廣泛使用的特殊氣體，近年，隨著國內光電、半導體產業不斷擴建，加上太陽能產業迅速興起，矽甲烷使用量大幅提升，氣體供應的方式也由小鋼瓶逐漸轉為450升Y鋼供應。然而，矽甲烷在常溫、常壓下具有自燃特性，一旦發生外洩，極可能引發重大工安事故，過去國內、外均曾發生因矽甲烷外洩所引發的火災及爆炸案例。 國內、外法規針對矽甲烷供氣系統及儲存場所設置，已制定相關安全規範，依據國內公共危險物品及可燃性高壓氣體設置標準暨安全管理辦法，可燃性高壓氣體儲存場所面積大於25平方公尺，儲存場所與易燃固體保護物距離至少為15公尺。但是，國內既設工廠要符合上述安全距離並不容易，因此，若儲存場所與保護物之間設有防爆牆者，則安全距離可縮減為一半。然而，目前國內法規僅針對防爆牆與儲存場所的設置距離，以及不同防爆牆材質所需最小高度及厚度予以規範，並未針對防爆牆的面積進行明確定義。 國外氫氣爆炸特性研究證實，防爆牆的正確設置可有效消減牆後過壓的情形，但是，對於矽甲烷相關研究相當有限。若使用實驗的方式不但耗時、昂貴且具有高度危險性，因此，本研究利用FLACS電腦模擬軟體，針對矽甲烷儲存場所，矽甲烷外洩可能造成的蒸氣雲爆炸進行後果模擬，探討不同防爆牆形狀、防爆牆設置地點和矽甲烷釋放量之間的關係，目的在於提升大宗矽甲烷儲存場所的安全。 Because of the highly successful development of the semiconductor and liquid crystal display industries and the rapidly emerging solar cell manufacturing in Taiwan, the consumption of silane has increased tremendously over the years. To meet the increasing demand, existing and new fabrication facilities have shifted from the traditional gas cabinet to bulk special gas supply system with cylinders 10 times larger than regular cylinders in volume. A distinct advantage of the so-called Y-cylinder, in addition to ample supply, is the reduced frequency of cylinder change since a notable percentage of accidents involving silane is caused by improper handling or erroneous cylinder change procedures. However, consequences of an accidental release of silane from Y-cylinders are much more severe than regular cylinders. Ignition and/or subsequent explosion of silane releases are difficult to predict because of the variations in gas yard geometry and the ambient conditions since it is required by Taiwan regulations to locate the gas yard outdoors. In addition, according to Public Hazardous Substances and Flammable Pressurized Gases Establishment Standards and Safety Control Regulations, a safety distance of 15 meters has to be maintained between an adjacent building and the hazardous substances if the floor area of the storage facility is greater than 25 square meters. Since such a safety distance is not readily available in most high-tech facilities, a compromised solution to reduce the safety distance by one half is the installation of blast wall between the building and the hazardous substances. Unfortunately, no specific design criteria such as shape, size, location, etc. have been provided by the competent authority. This study presents computer simulation results of silane release and subsequent explosion from the pressure relief device of a Y-cylinder. The Flame Acceleration Simulator is used in this study because of its flexibility in handling plant geometry and fuels. It is assumed that explosion characteristics of the released silane can be described by vapor cloud explosion. Effects of the blast wall’s shapes, dimensions and locations on reducing overpressure of the silane blast wave are studied in detail. To broaden the scope of this study, two silane release rates are employed. It is hoped that results of this study can be used to improve the design and installation of blast walls in bulk silane storage facilities.
