本研究先以定性安全評估方法 - 危害與可操作性評估方法 (Hazards and Operability studies, HAZOP)找出石化製程相關危害因素，並提供適當改善措施，再結合半定量安全評估方式 -保護層分析(Layers of Protection Analysis, LOPA)估算出事故發生嚴重度等級與發生機率，並分析系統可接受風險程度，以降低事故發生機率。根據本研究提供之方法，環己酮製程之事件發生的可能性可從3~10%有效降低至.01~0.001%，同時達到不同嚴重度等級的可接受風險程度，透過此次製程安全評估來監測重大危害並實施控制措施，就能有效避免重大事故發生。

This thesis uses a qualitative safety evaluation method, HAZOP (Hazards and Operability Study), to figure out the process related factors of hazard and provide a proper suggestion. We further combine with a semi-quantitative risk evaluation method, LOPA (Layer Of Protection Analysis), to evaluate the probability and the severity rank of accidents and analysis the acceptable risk level in order to reduce accident frequency. According to our method, the accident frequency of cyclohexanone process can be reduced from 3~10% to 0.01~0.001%, meanwhile, achieve the acceptable risk level for each different severity rank. Through the proposed method for PSM (Process Safety Management) to monitor superior hazards and implement regulatory measures, the major accidents can be efficiently avoided.