Study On Diffusion Law And Risk Assessment On Poison Gas Leakage Under Earthquake In Chemical Enterprise

In recent years, earthquakes occur frequently, people's life and property are caused huge losses, ecological environment has been also deteriorated. In order to mitigate earthquake disasters brought to the people. Domestic and foreign scholars have more and more researched in aspects of earthquake. The main direction of research is built (structures) on seismic engineering, and it is not rare which secondary disasters are caused by structural damage after earthquake, such as toxic gas leakage and diffusion. But the research with the combination of the secondary gas leak and the risk of making the project site is rare. With the rapid development of chemical industry, chemical enterprises which features are produce continuous strong, bad production conditions, toxic and so much hazardous substances are more and more, and the increasing scale, the consequences of an accident is more and more serious, secondary disasters caused by earthquakes are more and more. Secondary disasters caused by earthquake in chemical companies, it is a series of disasters which are caused by earthquake on the chemical raw materials, auxiliary materials, products, intermediate products and production process of waste water, waste etc, such as explosions, fire, poison, pollution and so on. Among the affect of secondary toxic gas leak and spread caused by earthquake is regiona on people's lives and property and ecological environment. The main content of this article is to simulate on secondary toxic gas leak and spread toxic in chemical enterprises after earthquake, and puts forward the risk assessment model, to provide the theoretical support for the project site of the Chemical Industry. Main contents and the results are as follows:1. Using fluid simulation software (FLUENT), take liquid chlorine tank leak diffusion after earthquake for example. According to the length of leak on the leak source, the article simulated to the process of leak and diffusion of two cases such as limited time leakage and continuous leakage. The simulation results show:(1) when continuous leak, the gas diffusion to stabilize after a certain point, the point of concentration will not change over time, but remained at a constant concentration;(2) when limited time leakage, a point of concentration changes with time first increased and then remained stable in a short time, and finally reduced immediately.In addition, based on continuous leakage simulation, the affect factors of the leak and diffusion were analyzed, In this paper, gap size, wind speed, and obstacles are three factors were simulated and analyzed. Simulation results show that:As the gap size increases, the chlorine to reach the same point of time getting shorter with the premises, and the increasing concentration; With the external wind speed increases, the chlorine time to arrive at a point along with shorter and shorter, reducing the rate of increasing concentration; The role of the low wall, the gas diffusion changes in the flow field changed, the spread of the concentration of chlorine decreased, but the change of obstructions and the distance between the leak I found in the case of low barrier from changes in gas diffusion flow field is small.3. Improved the area of quantitative risk assessment model is used in seismic risk assessment of toxic gas leak. The probability of the secondary gas leakage accident and the probability of individual death caused by the secondary gas leakage in a certain point to be as factors to calculate the point of personal risk. And the analog data of the concentration in a certain points over time by FLUENT is introduced the probability function on the consequences of toxic leak, we can get the probability of individual death at a point by integral on concentration and time. And it was verified by a practical example, the results show that the method is feasible.