Study On Environmental Security Vulnerability Of Chemical Enterprises

Due to the large number of dangerous goods involved in chemical enterprises,once the leakage,fire and explosion accidents occur,the human health and ecological environment will be seriously threatened.The current control and prevention of chemical accidents is mainly studied from the identification and evaluation of hazard sources,and ignores the influence of the disaster bearing body on the occurrence of the accident.The effects of the same factors on different bearing bodies will result in different accident consequences.The more vulnerable the body is,the more serious the accident will be.Based on the above considerations,this paper considers from two aspects of disaster risk factors and disaster bearing bodies.Through the theoretical analysis of the concept of vulnerability and its constituent elements,it starts from exposure,sensitivity and adaptability.On the three aspects of personnel,environment and equipment of chemical enterprises,the evaluation system of environmental safety vulnerability of chemical enterprises is constructed.A fuzzy comprehensive evaluation method based on data envelopment analysis was adopted to evaluate the environmental safety vulnerability of each production unit of a chemical enterprise in southwest China and identify the most vulnerable production units.Then,the classical Gaussian plume model is used to predict the occurrence of sudden environmental pollution accidents in the most vulnerable units.Finally,Pathfinder evacuation software is used to carry out emergency evacuation research for employees in affected areas based on the impact of accident prediction.Objective to evaluate the environmental safety vulnerability of chemical enterprises,to provide effective measures for the control and prevention of accidents,and to reduce the environmental and security risks of chemical enterprises.Taking a chemical enterprise in southwest China as an example,according to the analysis of the vulnerability of the enterprise,the results reflect:(1)Heat supply,Compression and synthesis department and Liquid ammonia storage are strongest physical vulnerability,and all of them efficiency value are 1.(2)After adaptive compensation,the efficiency value of Liquid ammonia storage,Compression and synthesis department and Heat supply decreased from 1 to 0.7653,0.7524,0.7484,and the most vulnerable unit was Liquid ammonia storage.In this way,the accident of ammonia leakage in liquid ammonia storage unit can be predicted.Prediction shows that:The vertical axis of the horizontal axis of the death zone,the serious injury area and the light injury area is 180 m,520 m and 1100 m respectively,and the vertical coordinates of the concentration curves are 28m,52m and 88m respectively.The affected area is distributed in Liquid ammonia storage,Power supply unit,Urea production,Laboratory,Synthetic ammonia unit,Nitrogen generation,Warehouse and Packaging building.According to the delineation of the influence range of liquid ammonia leakage,the evacuation of employees in the affected area is studied.The results showed that:(1)The pathfinder software was used to simulate the evacuation of employees in the normal state of the factory and the liquid ammonia leakage state.The simulation results show that in the normal state,the evacuation of all employees to the gate of the plant requires 328s,and the time of evacuation of all employees to the gate of the factory gate is 626s.(2)Death zone of1-2,1-1 and liquid ammonia storage unit were 14s,22s and 37s respectively.The fastest evacuation of the seriously injured area was the Decarburization and methanation department,which took 37s.The longest evacuation time is the laboratory,which requires108s.The warehouse evacuation in the minor area is the slowest,requiring 148s.The fastest evacuation is the Desulfuration department,which is 45s.(3)Warehouse,Compression and synthesis department,Laboratory,Urea production,Water supply,Power supply unit,Wastewater treatment department,Liquid ammonia storage which unit under the conditions of gas leak evacuation time is longer than under the normal state of evacuation time,this is because those unit of the evacuation to avoid gas,choosing the most suitable path for evacuation.(4)When the safety factor k_s is 1.5,the alarm time of the dead zone shall not exceed 36.5s,the alarm time in the minor area shall not exceed 83s,and the alarm time in the injured area shall not exceed 339s.If the alarm time is over,the employee may be in a dangerous state,the death rate of 1-1 in the death zone is 2%,the death rate of 1-2 in the death zone is 3%,and the death percentage of the Liquid ammonia storage is 6%.The death rate of the Packaging building in the serious injury area was 2%,the Warehouse 1%,the Laboratory 3%,the Urea production 2%,and the death percentage in the minor injury area was 0%.In this paper,DEA and Fuzzy coupling method are used to analyze the vulnerability of each production unit of a chemical enterprise in southwest China.For the most vulnerable liquid ammonia storage unit,the occurrence of sudden liquid ammonia leakage accident can be predicted and determined,According to the division of influence scope,the study on the evacuation of employees within the scope of influence.Although some achievements have been made,further research is needed on the construction of the indicator system,the expression of accident dynamics and the precision of the evacuation model.