Research On Risk Assessment Methods Of Liquid Ammonia Tank From Life Cycle Perspective

In recent years,with the rapid development of China's chemical industry,liquid ammonia as an important chemical raw materials and products are widely used in various fields of chemical industry.However,due to its physical and chemical characteristics,if t leakage,it may cause poisoning and explosion accidents.So the risk of liquid ammonia tank caused more and more attention.Currently,about the risk assessment methods of liquid ammonia tank,in addition to RBI method is to segment the life cycle of liquid ammonia tank to assess the risks,most of the assessment methods are considered risk liquid ammonia tank at some future time,not can risk reflected in the entire service life of the tank.This paper from the perspective of the life cycle of the liquid ammonia tank in use stage as the research object,take the time as the main line.On analyzing the industry life cycle risk assessment method to study the status quo of the premise,to analyze the failure mode and mechanism analysis and establish the failure probability prediction model and consequence of failure model.Then,to get the liquid ammonia tank risk assessment methods and prediction and analysis of liquid ammonia tank in different service period of the change in risk.Firstly,we study the life cycle status of research in the areas of risk assessment,to discuss the pressure vessel and pressure pipe failure analysis and lifetime prediction.To describes the theoretical life cycle,reliability theory and the relationship between reliability and failure,as well as various failure physical model.Secondly,according to the life cycle theory of liquid ammonia tank lifecycle defined its phasing,specifically partitioned into the design phase,manufacturing and installation,operational and decommissioning phases.And each phase of the existence of risk and risk factors analysis and research results show that the use phase of the life cycle within the ammonia tank only possible accident damage on the surrounding environment of phase occurs.So this paper the main starting venture liquid ammonia tank from the use phase caused by the life-cycle perspective.Thirdly,liquid ammonia tank failure analysis and damage mechanism analysis,failure physics model in this paper(stress-strength interference model).The stress-strength interference theory,and reliability theory,failure probability of liquid ammonia tank model,combined with the individual probability of death liquefied ammonia tank models of the consequences of the danger zone,and the calculation of personal risk,risk assessment methods to determine the liquid ammonia tank.Finally,an example of a liquid ammonia tank failure analysis,failure probability according to the established model to predict the probability of failure within the tank different service life.According to accident consequence model to calculate the consequences of the accident and to determine the area of influence of the individual hazardous areas probability of death;then according to individual risk calculation method to predict the different service lives leakage of personal risk for each danger zone poisoning within individual risk and explosions and poisoning each hazardous area explosion within the superimposed individual risk in the region occur simultaneously.According to the forecast confirms that the individual risk of liquid ammonia tank on the surrounding environment in a particular place with the result of changes in service life,in order to arrange for the enterprise storage tank maintenance frequency,and set the appropriate security measures to provide a reference.