| The prevention of explosion accidents from the source is a difficult problem to be solved in the chemical process.Based on the theory of accident causation and risk coupling,the mechanism of the nonlinear coupling between risk factors and the evolvement of explosion accident was discussed in this paper.The hierarchical coupling network analytical model was thus introduced.The coupling probability between the risk factors was statistically analyzed and the importance degree was graded.The interactions between the risk factors were quantitatively calculated.Bayesian network model is constructed to analyze the main accident causation chain and the key nodes of accident causation network.The chain-cutting technology based on risk decoupling is put forwards,which provides a new way to prevent the explosion accidents in chemical process from the source.In this paper,the following conclusions are obtained:(1)Based on the mechanism analysis of the inner ring causation and the outer ring excitation of chemical process explosion,a three-dimensional hierarchical coupling network analytical model with three levels,four risk factors and 15 risk factors was constructed,providing a macroscopic structural framework for the analysis of accident causation.(2)The statistical analysis of the chemical process explosion accidents at home and abroad in recent years was carried out from the theory of risk coupling and the importance degree of coupling causation was thus graded.It was found that the probability of risk formation for the double coupling of the seven factors was high.Among them,the coupling between the lack of necessary rules and regulations with operation errors was the highest,around 75%.In addition,most of the two-factor coupling were found to be the causation characteristic of weak coupling.(3)The quantitative analysis of the interaction between the two factors provides a basis for building a microcosmic structural framework of accident causation.The results show that six factors’ reason degrees were relatively high: the lack of necessary rules and regulations,education and training,communication,safety awareness and technical knowledge and the poor external operation environment,which were the main factors of the accident causation and the indirect causes of the accident.In addition,six factors’ reason degrees were relatively low: equipment defects,protective defects,electrical hazards,fire and other ignition sources,signal defects and operation errors,which were also the direct causes of the accident.The central degrees of the following factors were relatively high: the lack of safety awareness,monitoring errors,operation errors and command errors,which were the key risk points of the explosion accident.(4)The method of transformation from the hierarchical coupled network analysis model to the Bayesian network was proposed.It was applied to the case analysis of the explosion caused by the explosive gas mixture inside the vinyl chloride monomer tank.The most probable causation of the accident,the occurrence probability of different accident causation chain and the key nodes of the accident causation network were thus obtained,providing a strong basis for the prevention of the accident from the source.(5)Based on the risk decoupling,a practical chain-cutting techniques of accident causation chain for different coupling levels was presented. |