Research On The RiskAnalysis Of Ammonia Diffusion Based On3D Dynamic Simulation Technology

Ammonia, a green, inexpensive refrigerant, is widely used in the food processingindustry and salt chemical enterprise. In recent years, the ammonia leak accidents haveoccurred increasingly and been widely payed lots attentions of the whole society for itstoxicity, fire and explosion hazard. In this paper, a ammonia-site investigation of fourammonia companies was conducted in Xuzhou. I investigated and analyzed the evacuationpsychology and behavior of employees and personnel nearby. Risk analysis method based onnumberical simulations of the diffusion of ammonia leak and personal evacuation in normaland abnormal state were also proposed in this paper.Dangers of ammonia, the main application, process principles, security risks and et.alwere grasped by investigation of four ammonia companies. The survey found thattransportation pipeline valvesa, flanges and joints and other parts of the tank easily wreck dueto corrosion damage. There are many security risks in the use and storage of ammonia. Thusbasic ammonia spill events were researched and ammonia spill accendient trees was drawedto prevent ammonia leak acciendent.Applied statistical analysis method to study the evacuation psychology and behavior ofemployees and personnel nearby. The survey showed that five factors which mainly affect thepsychological behavior of employees are work experience, whether know the location andrisk of liquid storage tanks, whether experienced evacuation drills and safety education,whether known evacuation routes and escape direction. And six factors which mainly affectthe psychological behavior of personnel nearby are gender, age, education level, whetherknow the possibility of gas leaks, whether experienced evacuation drills and safety educationand whether known evacuation routes and escape. Meanwhile, The survey also showed thatthe pre-action evacuation time, an important evacuation parameters, is separately1min and5min for employees and personnel nearby.Based on the above investigation, large eddy simulation using CFD technology wasapplied to analyze the ammonia leak diffusion. Lethal area, seriouslyinjured area and injuredarea are separtrely355m,602m and1851m which is coincide with the theoreticalcalculations. The dangerous time of whole lethal area, seriouslyinjured area and injured areaare separtrely826s,1512s,4158s. Meanwhile, Pathfinder, an evacuation software, was alsoapplied to study the personal evacuation process in normal and abnormal state. The simulationshowed that the evacuation efficiency in normal state, evacuees could evacuated in openfarmland, is improved by25%. The needed evacuation time for lethal area, seriouslyinjured area and injured area are separtrely355s,617s and1689s. At last, a critical alarm time isproposed to provide technical guidance for the emergency rescue.