公路槽車洩漏、火災及爆炸事故模擬研究

Chemical Release, Fire and Explosion Simulation of Tank Truck Accidents

目前國內化學品的運送大多採用公路槽車之運輸方式，運載化學品之公路槽車若於運送過程發生事故，將可能造成運載物洩漏或發生火災爆炸等嚴重事故，不僅危害運輸勞工、道路使用者、救援人員及附近居民的生命財產安全，也破壞了自然生態環境，所需付出的社會成本甚鉅。因此若能事先模擬各項事故情境所可能造成之危害後果及規模，以作為事先規劃緊急應變措施之依據，或於事故發生時作為應變救災單位參考，相信將可有助於降低災害對人員、自然及社會環境所帶來之衝擊。本研究利用美國 ALOHA 及 ARCHIE 兩套模擬軟體進行事故後果模擬，模擬情境依美國環保署風險管理計畫中建議之最壞情況及替代情境設定，模擬對象為運載苯乙烯、1,2- 二氯乙烷、對二甲苯、苯、丙烯腈及醋酸等 6 種易燃液體之公路槽車。模擬結果將可作為評估或劃分死亡區、禁區、影響區、除污區及疏散區等參考標的，由結果發現物質之擴散終點值距離主要受其蒸氣壓及終點值所影響，且此 6 種物質之擴散終點值距離與液池面積之平方根呈現良好線性關係，利用迴歸分析所得之線性參數將可協助救援單位迅速劃分各隔離區域，另外，此結果也顯示如能儘速圍堵洩漏物於小面積，將可有效降低終點值距離，縮小危害影響範圍。

Most chemicals in Taiwan are transported in tank trucks. A traffic accident involving a tank truck loaded with hazardous materials can cause release, fire or explosion. Sucn an accident will not only jeopardize the safety of the driver of the truck as well as the occupants of other vehides, rescue workers, and local residents, but will also pollute the environment and cause societal losses. If the consequences of an accident can be simulated, the results can be applied to the planning of emergency response measures by transportation operators and to design isolation zones for rescuers. These preparations would reduce the impact of tank truck accidents. Two simulation software packages, Areal Locations of Hazardous Atmosphere (ALOHA) and Automated Resource for Chemical Hazard Incident Evaluation (ARCHIE), with the scenarios suggested by the U. S. Risk Management Program (RMP), were used to simulate the consequences of tank truck accidents with styrene, 1,2-dichloroethane, p-xylene, benzene, acrylonitrile and acetic acid as the hazardous chemicals. The simulation results can serve as factors in assessing and dividing the hot zone, evacuation zone and warn zone on site. Results indicate that the dispersion distance of vapor in the air is strongly affected by the are of the liquid pool on the ground and linearly related to the square root of the liquid pool area. Therefore, if the released materials can be isolated in a small area, the hazardous zone will be decreased and the consequences reduced.