Study On Leakage Mechanism Of Liquid Ammonia And Control Technology In Synthetic Ammonia Enterprises

The chemical accidents have the characteristics of strong burst,great harm,chain accidents,and the difficulty of emergency treatment.With the rapid development of modern society,ammonia in industrial demand is gradually increasing,the number of production and the number of synthetic ammonia enterprises has also been gradually expanding.However,the production process of synthetic ammonia enterprises is very complex,and exists many production link of high temperature and high pressure.And it is often associated with a series of inflammable,explosive,easy to leak disaster risk.Once the accident happened,it easily lead to chain fires,explosions and other vicious accidents.If you do not take scientific and effective prevention and control measures in time,it may cause huge,irreparable casualties,property damage and environmental pollution,and so on.Harmful consequences are quite serious.In the ammonia plants,liquid ammonia itself is flammable,explosive and corrosion characteristics,equipment in the long-term operation and the process of store-use,is often eroded by liquid ammonia,and become fragile.Once damage occurs,it will lead to liquid ammonia leakage.Fire source can easily cause fire and explosion.Therefore,in order to ensure work safety production of synthetic ammonia enterprises,preventing the accidents occurrence of synthetic ammonia production process is a very important work.Firstly of all,the thesis analyzes the production process of synthetic ammonia enterprises,on the basis of introduction of ammonia production process and main facilities and facilities,identifying the dangerous and harmful factors exists in the process of ammonia production.And it counted 22 liquid ammonia leakage accidents which were reported by the media within the past 5 years.We found that most of the leakage occurred in the production equipment and storage equipment.The results show that the location of the accidents is usually not far from the residential area,and often lead to group evacuation.Secondly,the thesis analyzes leakage mechanism of liquid ammonia.According to the physical and chemical characteristics of liquid ammonia,and it analyzes the causes of leakage on liquid ammonia and the internal factors influencingthe diffusion of liquid ammonia(the leakage location,the leakage gas density and the leakage amount)and external factors(wind speed,wind direction,temperature and humidity,atmospheric stability,ground condition)from four aspects: human,substance,environment,administration.And then,taking the ammonia storage tank which constitutes the major hazard source of the ammonia enterprise as an example,we can carry out the toxic region calculation.By constructing the physical model of liquid ammonia storage tank,using Ansys software to build the model and divide the grid,using Fluent software to build liquid ammonia leakage visual simulation.We can analyze the ammonia leakage in different wind direction of the diffusion concentration with time changes.We analyze and predict the consequences of leaking liquid ammonia tanks,and this result provides scientific and effective guidance to personnel evacuation routes in the emergency rescue drill.At the same time,companies can use this method which refers to the production of other toxic gas diffusion to make a quantitative assessment of acute poisoning.Finally,In this thesis,countermeasures are put forward to control the accident of liquid ammonia leakage from the four aspects: personnel distribution and evacuation route,liquid ammonia leakage alarm system,emergency rescue and liquid ammonia leakage prevention and control.From safety technology and safety management,prevention and control accidents of ammonia production enterprises become more and more scientifical.