| That complicated processes,harsh operating conditions and highly influencing factors coupled with extreme conditions such as high temperature,high pressure,low temperature,vacuum,high flow rate,and high rotational speed are the chemical process system’s characteristics.Process safety accidents are mostly caused by "changes" in the relative macroscopic or microscopic systems,such as small flows and low liquid levels.If operating conditions of the system are no longer fall within the expected safety limits caused by such "changes",the system will fail.The faults presented by a single device or process often create cascading effects relying on the links between the cell systems,eventually becoming an accident.Process safety accidents are mainly presented on the macroscopic system scale,and most of the specific research data are carried out on several relative microscopic system scales.Therefore,the quantitative analysis of the scale effect of process safety accidents is used to predict the evolution law of accidents and determine the key monitoring targets.It is of great significance to determine the priority of accident handling.The study of the risk on different system scales is needed that quantitative evaluation of process safety risk based on the scale effect.The probability model of leakage accident on the scale of process variables is established;the domino accident scenario on the equipment level scale is analyzed;an integrated risk assessment model was established.The specific research content is as follows:(1)A scale-based probability estimation method for process safety leakage accidents is proposed.Multi-scale thinking was introduced.On the relative microscopic scale,the process deviation variable was selected as the basic event.As the scale was increased,the influence of human error on the process deviation was taken into account on the macroscopic scale,and the human error factor was used to correct the process deviation probability.The corrected basic event probability is used as the input of the fuzzy Petri net model,and finally the leakage accident probability can be output.(2)Based on the cascading effect among devices,an accident scene analysis method based on domino effect is proposed.Combining the event tree analysis method,the specific analysis flow of domino accident is given,and the domino accident scene and probability calculation process caused by the initial accident are analyzed,which the problem is solved effectively that only the secondary accident is analyzed by the traditional analysis method(3)Aiming at the risk of accidents in the chemical process,a comprehensive risk assessment method based on the scale effect is proposed.Considering on risk action chain during the whole accident process,a risk assessment method based on “risk level—management factors—receptors" is proposed. |
