Diffusion Simulation Test Of Leaking Hazardous Chemicals In Ningbo-Zhoushan Waters Based On FVCOM

In recent years,with the rapid development of China's coastal economy,the construction of industrial parks,which is dominated by chemical industry in coastal petrochemical areas,is in full swing.But at the same time,offshore chemical industry has gradually become a high-risk area for hazardous chemical accidents.The environmental risk of marine chemical leakage has become an important factor threatening China's marine ecological safety.Accidents such as hazardous chemical leakage often lead to significant casualties and property losses,and also cause serious damage to the surrounding environment,which not only directly threatens the local ecological safety,but also poses a serious threat to the life and production of the surrounding people.Coastal construction in Ningbo has a national strategic petroleum reserve base and a series of downstream chemical industry clusters,focusing on the development of petrochemical and energy industries,forming the coastal structure of heavy chemical industry,and the environmental risk situation is extremely severe.Therefore,it is of great academic value and practical significance to establish the leakage diffusion model of hazardous chemicals and analyze the diffusion behavior after the leakage of hazardous chemicals,so as to provide a scientific basis for emergency measures and related work after hazardous chemicals leakage.This paper establishes the leakage diffusion model of hazardous chemicals,analyzes the behavior within 24 hours after the leakage in this area.The specific research contents and conclusions are as follows:1.This study investigate the natural geographical environment and the distribution of hazardous chemicals in Ningbo waters,get the basic data of hazardous chemicals'distribution area,main types,species and quantity.According to the analysis results,three representative sites,Zhenhai port,Cezi channel and Beilun anchorage are selected as leak test sites.And Epoxy Chloropropane is selected as a typical soluble and conservative chemical product,Cumene as a typical insoluble floating chemical product for diffusion simulation test.2.Using advanced FVCOM numerical ocean model is applied to simulate the tidal current in Ningbo waters and the surrounding waters(120°10?E~124°30?E,28°20?N~34°15?N),using the measured data of the numerical model calculation results are verified,including validation of tidal level and velocity and direction.The simulation results of tidal level are in good agreement,the trend is consistent,and the error is less than 10%;The velocity and the trend of flow are in line with the actual situation.The error of the flow direction is basically within 15 degrees.It can be considered that the calculation result is accurate and reliable,and it can be applied to the simulation of the flow field in the area,so as to meet the demand for the calculation of the diffusion of hazardous chemicals.3.According to the survey of the natural geographical environment of Ningbo waters and the general situation of hazardous chemicals,different simulation schemes for the leakage of hazardous chemicals are made.On the basis of verification of hydrodynamic field simulation,we simulate the diffusion within 24 hours after the leakage of 100 tons,500 tons and 1000 tons of Epoxy Chloropropane of the summer flood and ebb tide in Zhenhai port,Beilun anchorage,Cezi channel.The threshold0.02mg/L of Epoxy Chloropropane is taken as a safe concentration.Meanwhile,drift diffusion simulation of insoluble floating chemicals of Cumene was carried out.The results of the simulation are obtained as follows:The leakage of different types of hazardous chemicals was simulated with different modules,Epoxy Chloropropane was calculated by DYE(dyeing tracking)module,and Cumene was calculated by PT(Lagrange particle tracking)module.According to different grades of the accidents,as is indicated by the simulation result,the concentration of Epoxy Chloropropane will be diffused to below safe concentration(0.02mg/L)after 24 hours of leakage for ordinary accidents.As to relatively big accidents,there are still small area of waters(5~20 km~2)which have been polluted with concentration exceeding the safe limit after 24 hours of leakage.As to major accidents,however,there are still large area of waters(70~250 km~2)which have been polluted with concentration exceeding the safe limit after 24 hours of leakage.From the aspect of different tides time at diffusion,because of the difference of the terrain,speed and direction of the tidal current,no matter where the leak occurs,the speed of hazardous chemicals spread at the ebb tide is faster than the flood tide.From the different leakage points,when the leakage occurred at Zhenhai port,the leakage of hazardous chemicals was basically spread between the Jintang Island,Daxie Island and the Ningbo coast;when the leakage occurred on the Cezi channel,the leakage of hazardous chemicals spread along the channel with the flow of water;when the leakage occurred at the Beilun anchorage,the leakage of hazardous chemicals is along the Ningbo Chuanshan peninsula,spreads to the southeast side.The simulation shows the diffusion situation of 24 hours for different simulated leak test schemes.Emergency monitoring department can respond quickly according to the prediction and simulation of different situations,and make corresponding measures in the first period of tidal cycle.