Risk analysis and hazard control of chlorine gas leakage in a water supply plant
|關鍵字:||氯氣;危害與可操作性分析;失誤樹分析;淨水廠;chlorine gas;Hazard and Operability Analysis;Fault Tree Analysis;water purifying plant|
Under standard temperature and pressure conditons, chlorine exists in yellowish green gas form. It has suffocating odor which irritates the respiratory system, and is poisonous and corrosive. Without proper care in operation and management, it will pose serious intoxication hazard and environmental impacts. In Taiwan, chlorine is commonly used as a disinfectant. To avoid the potential danger of chlorine leakage, it is necessary to conduct a thorough study through an assessment method and to implement a standard safety management procedure to reduce its impact. This study deals with an incident of a chlorine leakage during the water-purifying process in one of the water supply companies in northern Taiwan. Focusing on the transportation, storage, injection, maintenance and emergency response of chlorine storage barrel, this study investigates the factors that trigger the leakage. The danger in the chlorine injection system evaluated first to analyze its risk once a leakage takes place. Later, the Hazard and Operability Analysis (HAZOP) is incorporated and the outcome is used to categorize its potential danger. After removing insignificant and redundant factors, the possibility of a leakage is calculated through the Fault Tree Analysis, FTA. Finally, the results of risk categorization by HAZOP and and the possibility of the leakage by FTA are integrated to develop methods to reduce the possibility of leakage and avoid its impact. The risk control performance is further evaluated after the improvement in operation and management. This study hopes to reduce or avoid the possible chlorine leakage, and ensure the safety of personnel and equipment, and minimize the environmental impacts of the water-purifying process.