Research On The Laws Of The LNG Leakage Diffusion

LNG (liquefied natural gas) is compressed gaseous natural gas, methane will become liquid formed after cooling with a temperature of about-162 ℃, which was stored in cryogenic tanks. LNG is acclaimed as a clean fuel quality in the world’s energy system.In recent years, with the support of relevant national policies, its consumer market is in short supply, in a broader development prospects. As a clean fuel, LNG has the following advantages:First, after the cooled liquefied natural gas, compared with the original, its volume reduced 600 times, so that its transportation and storage efficiency is greatly improved; secondly, LNG is purer than other fuels, which can perfect combustion, and the only product are carbon dioxide and water, which is clean fuel pollution that they are good for environment; In addition, LNG can be used as a motor fuel in high quality, compared with gasoline, its price is relatively low, in good antiknock performance, and economic.Currently, the main mode of transport LNG are in following three ways pipeline transport, road transport and shipping. As the main device for road transport, the quality and safety of cryogenic LNG tanker plays a key role in reducing LNG accidents.LNG’s temperature is very low, with explosive properties., Not only for human life, property losses, the surrounding environment will also be caused great damage by leakaging during transportation in the event. Therefore, the study of the diffusion of LNG leak accident law and proposed pre-control measures have theoretical significance and practical value is very important.This paper analyzes the nature of LNG from its spill type, simulating the use of C language programming for LNG storage tanks were leaking and spread two stages rules summarized leakage and diffusion law and proposed LNG leak pre control measures, the specific work as follows:(1) for example, Rudong LNG component, this paper analyses its physical and chemical properties, discussing the types of accidents and hazards LNG leak after summarizing the relevant researches on LNG leakage, deeply analyses of the LNG leak after aerosol diffusion process, summing up the factors that influence the spread of aerosol analysis from multiple perspectives.(2) in fluid mechanics and thermodynamics theory, the use of the Bernoulli equation, the mathematical model of the LNG storage tank leak hole, through the C programming language, developed a liquid leak simulation software, and the use of control variables were studied law leakage time of strong leaks leak source port area, as well as changes in surface elevation in the tank pressure. The simulation results show that:the leak port area of change is particularly important source of leakage strong impact on; the remaining factors also affect the leak source intensity changes to some extent, but the effect is not very obvious, especially when a high pressure situation in the tank Under the leak source intensity changes with time is minimal.(3) The board model and the Gaussian model combined weight change were simulated gas diffusion and non-heavy gas diffusion concentration of a substance in the range of gas clouds downwind distance by controlling wind speed and atmospheric stability, were studied both from the impact of change on the spread of gas clouds, and a comparative analysis of the scope of the danger area. The simulation results show that: the proliferation of wind speed change impacts on LNG gas cloud is particularly important, the wind speed increases, exacerbated by the proliferation of LNG vapor to reduce the scope of the explosion hazardous areas; LNG gas atmosphere more unstable the more severe the degree of diffusion, The faster the gas concentration decreases, the risk of explosion area is smaller, but its impact is not obvious effect changes in wind speed.(4) above the theoretical researchs and numerical simulation analysis, this paper put forward prevention measures and other aspects of the emergency rescue plan from monitoring, construction, fire-proof, anti-physical explosion, anti-hypothermia frostbite LNG leak after the accident.