Research On Back-calculation Of Source Intensity And Position Of Toxic Gas Dispersion From Road Tank Car

For road transport can achieve direct transport, and can connect to other modes oftransport, it has become the main way to transport gas chemicals; for tank vehicle can realizethe loading and unloading mechanization, and can improve the loading and unloadingconditions, it is the main bearing tools of road transportation of liquid and gas chemicals.Because of the dense population and large vehicles of the road and the surrounding, once thegas leakage of chemicals in the transport process, especially the toxic gas leak, if it was notcontrolled in time, it would cause casualties on the road and the surrounding, it also causeddamage to the environment. Therefore, in order to determine the strength and location ofleakage source quickly after the accident, to judge the effects of the accident range andconcentration, the government rescue departments from passive safety research of accidentand emergency problem, they are obliged to identify the risk of gas transport source, and it isnecessary to estimate the toxic gas leakage source of transportation.Firstly, to identify the toxic gas transportation of dangerous source tank, the passivesafety study of the government rescue department belongs to the decision problem after theaccident, analyzing the potential danger before accident in order to reduce the impact andscope of the accident. First, through the analysis of the causes for the leakage oftransportation of toxic gas, toxic gas leakage of truck includes four stages: initial event, thefirst accident, energy unconstrained flow and two accidents, energy unconstrained flow is thedriving force of two accidents. Second, through identifying first class and second class risksources of the poisonous gas tanker transport, analyzing from the toxic gas hazardcharacteristics, toxicity and harm pathway analysis of the risk factors inherent in the transportprocess of poisonous gas in order; analyzing in turn from the four aspects of people, vehicles,environment and safety management of toxic gas potential in the transport process factors.Third, through researching the toxic gas tanker leak countermeasure, points out that thegovernment rescue departments should focus on emergency problems in the management ofaccident, the inverse research of source intensity and position of toxic gas leakage is thefundamental way to realize the timely rescue.Secondly, the concentration and diffusion scope under the direction of the toxic gasleakage source can be calculated according to the leakage source intensity, meteorologicaldata and diffusion model, so making sure the intensity of leakage source timely andaccurately is the base of emergency management. Then, by considering the actual situation inreality and according to the different leakage point location, status and the running of thetanker, four kinds of typical toxic gas leakage situation of transportation process are discussed:a stationary tank (point source) instantaneous leakage, static tanker (point source), continuous gas leakage stationary tank (source) continuous liquid phase leakage, mobile car (line source)continuous liquid phase leakage (mobile tank continuous gas leakage accident fierce, tankerdrivers easily detect and stop treatment, so the situation is still tank car for gas leakage).Among them, the wind sensor to monitor the concentration respectively choose Gauss puffcorresponding diffusion model and the Gauss plume diffusion model calculated and leakagesource values matching degree as the objective function to establish the model of static tankerinstantaneous leakage, stationary tank continuous gas leakage source intensity, the reducedinverse problem as an optimization problem to solve, and the object function is optimized bysimplex search algorithm, inverse determine location and intensity of leakage source. The twosituation is point source leaking, and the actual situation to form liquid pool and non-pointsource leakage problem is considered in still tank continuous liquid leakage; mobile tankcontinuous liquid phase leakage is similar to automobile exhaust emissions, car driving can beregarded as line source problem by a continuous point of leakage. Based on the original Gaussdiffusion, the model on the Gauss surface source and line source diffusion model is designed.In this paper, by simulating the monitoring data and using Matlab programming simplexsearch algorithm for solving the inverse problem of source intensity, and verify the feasibilityof the algorithm. The results show that simplex search algorithm can calculate results fasterwith smaller errors, it is suitable for multidimensional variables search.Then, this paper attempts to study a number of toxic gas tankers transport process of leakcase: two static tanker and instantaneous leakage, because it is likely to have the samemonitoring concentration in different leakage source combination, which leads to existmultiple extreme points in optimization problem, using the simplex search algorithm can onlyget a set of non-dominated solutions.Finally, using the inverse method of source intensity can timely and accurately get thereal source intensity value, and then calculates the pollution scope and the concentration ofthe toxic gas combined with the corresponding diffusion model, it has good theorysignificance and the practical significance that dividing toxic gas tanker transportation leakageinto four kinds of typical leakage discharge source intensity and location problem in theaccurate estimation. This paper not only provide a reference for the toxic gas transportenterprises and government rescue departments, but also provides a guide for prediction ofaccident and emergency rescue of toxic gas transport.