二硫化碳製程危害評估與風險管理

Abstract

摘 要 二硫化碳是無色、有毒、高度揮發性而且易燃的化合物液體，在工業上大量用於嫘縈棉、嫘縈絲、玻璃紙、及四氯化碳之製程，它具有毒性、易燃、易爆、等三大特性，在製程上如有操作或管理不當，極易產生中毒、著火、爆炸之危害。為防止意外事故的發生，有必要透過危害評估方法探討其危害性，並採取製程安全管理以降低危害。 本研究以某工業區一家生產二硫化碳工廠內危害風險較高的二硫化碳儲槽為對象，使用ALOHA後果分析軟體，模擬二硫化碳儲槽發生破洩時的最嚴重災害情境(worst-case scenario)及其他可能發生情境(alternative-release scenario)之危害影響範圍。 由ALOHA模擬毒性氣體外洩「最嚴重災害情境」結果，二硫化碳毒性氣體危害影響範圍已超出廠外周界，因此當二硫化碳洩漏時應儘速對影響範圍居民緊急疏散或引導儘量留在室內，避免外出活動，並將窗戶及空調設備關閉，直到濃度降低到安全濃度才可解除警報。由ALOHA模擬火災熱輻射、蒸汽雲爆炸之「最嚴重災害情境」及「其他可能災害情境」的結果發現，對廠外居民不會造成危害，但對廠內會造成危害，故當火災發生時，除應將廠內人員撤退至安全距離，並針對火災應有效控制，以避免引起爆炸。 除了需透過「最嚴重災害情境」及「其他可能災害情境」之危害評估外，工廠應重視製程安全管理的工作，並且應訂定緊急應變計畫書，模擬工廠可能發生情況，定期實施緊急應變演習，讓員工在處理意外事故時，能夠從容迅速完成，才能有效減少危害發生。

Abstract Carbon disulfide (CS2), a colorless, toxic, highly volatile and flammable liquid chemical compound; which are used extensively in the manufacturing of viscose rayon fibers, cellophane, and carbon tetrachloride. It has the characteristics of toxicity, flammability and explosiveness. If the process is operated and managed improperly, it is extremely likely that poisoning, fire and explosion will occur. In order to prevent the incident from occurring, we need to perform the hazard assessment to find out the potential risks and exercise the process safety management to reduce the risks. In this research we chose the storage tank of a carbon disulfide factory in an industrial zone as the target of study. ALOHA consequence analysis software was used to simulate worst-case scenario and alternative-release scenario from the breaking tank to understand the affected area and the magnitude of the risks. The results indicate that the affected area of the toxic carbon disulfide will go beyond the periphery of the factory. When carbon disulfide is released, the factory director must evacuate residents near the factory as quickly as possible, or persuade them to stay indoor and avoid outdoor activities. The windows should not be opened and the air conditioners must be turned on until the CS2 concentration falls below the safety threshold. The study also shows that the neighbors are not exposed to the risks of thermal radiation and vapor cloud explosion, while these accidents pose risks to the personnel in the factory. Therefore when the storage tank catches fire, we should evacuate workers to the safe areas immediately and control the fire effectively to avoid explosion. In addition to the hazard assessments of the worst-case scenario and the alternative-release scenario, the factory must take the process safety management seriously and establish the emergency response plan to simulate the scenarios that might have happened. Emergency response drill must be scheduled regularly so that worker can handle the incidents rapidly and effectively to reduce the hazards.