Limitations of the application of the Gygax cooling failure model for reactivity hazards assessment of chemical processes
At present,the reaction safety risk assessment technology in China's fine chemical industry mainly uses the Stoessel criticality classification method and ranks the reaction process hazard levels from 1-5 class.This method is based on the Gygax cooling failure model,which evaluates the reactivity hazard level of reaction systems under the assumption of a cooling failure condition.However,statistics on chemical reactivity safety incidents,both domestically and internationally,indicate that the cooling failure condition only accounts for a very small portion of the causes of such incidents(about 3％).Taking nitration processes as an example,the literature reports using the Stoessel criticality classification method indicate that most nitration reaction processes are classified as low risk levels.This contradicts with the fact that based on actual production incidents,nitration process is the dangerous process with the highest fatalities in China.The primary reason for this is that the Stoessel method only assesses the cooling failure scenarios in batch reaction vessels while it overlooks many other complex incident causes.This indicates that this classification method cannot accurately assess the reactivity hazards in actual chemical production,because it fails to cover most of the causes of chemical reactivity safety incidents and to propose effective accident control measures.On the other hand,the full-process reactivity hazard analysis(RHA)is based on assessing the accident chain of a chemical process from identifying the root causes of abnormal conditions to simulating the occurrence of reaction runaways,proposing corresponding protective layers,and thereby determining specific accident prevention measures.This approach is more suitable for enhancing actual process safety compared to the Stoessel criticality classification method.Therefore,it is recommended to conduct a comprehensive RHA analysis for the reactivity risk assessment of actual chemical plants,especially for hazardous processes rated at levels 4 and 5 high risk.
万方数据
维普
