Study On Emission Estimation And Diffusion Simulation Of Ship Exhaust In Port Area

With the rapid development of the trade and the process of economic globalization,the importance of shipping industry in the global transportation of goods is becoming more and more prominent.As the infrastructure of the shipping industry,the port plays a more and more important role,and the ships’exhaust pollution has also been serious,which attracts people’s attention.As a national important transportation hub,the cargo throughput of Shenzhen Port increased year by year,and the west area of Shenzhen Port undertook a large number of goods transportation of Shenzhen Port.The influence of exhaust gas produced by ship activities could not overlook.Therefore,the study on the emissions and diffusion of ship exhaust in the west area of Shenzhen Port is beneficial to the ecological environment and public health.And this study is satisfied with the depth requirements of regulatory,and provides strong support for in-depth development of emission reduction measures.This article is based on AIS data to estimate the ship emissions of the west area of Shenzhen Port.On this basis,Gaussian Plume Model was improved to simulate the diffusion of ship exhaust,and the detailed research content is as follows:Firstly,building ship exhaust emissions model and diffusion model respectively.Due to the lack of existing ship-related data,this paper established a detailed estimation model of important parameters such as ship engine power and ship’s maximum speed.The"bottom-up"method based on ship activities and Gaussian Plume Model are determined as the basic models of ship exhaust emissions and diffusion respectively.And the Gaussian Plume Model is improved in consideration of the reflection and absorption of the sea when the exhaust gas diffused to the sea surface.Next,calculating the exhaust emissions of ships and obtaining the ship emission inventory of the west area of Shenzhen Port in 2018,and analyzing the distribution characteristics.According to ship AIS data and the above model,this paper estimated the ship emission inventory in 2018 in the study area.The emissions of CO₂、SO_X、NO_X、CO、PM₁₀、PM_2.5 and VOCs from ships in 2018 in this area were 324920.2 t,2683.1 t,7273.0 t,615.5 t,398.6 t,366.8 t,and 295.9 t,respectively.This paper studied the emission distribution according to different types of ship,different months,and different operating conditions.The contribution rate of exhaust emissions of cargo ships and container ships is at the forefront.Among the year,the emissions in February were significantly reduced.In addition,ships’emissions in hotelling and normal cruising are relatively more significant than those in maneuvering and slow steaming conditions;in addition,this paper made recommendations for environmental governance according to the ship exhaust gas emissions.Finally,carrying out the simulation experiment of ship exhaust diffusion based on the ship exhaust gas diffusion model.Firstly,combined with the model determined above,the diffusion simulation experiment of CO₂,SO₂ and NO₂ is carried out respectively;this paper analyzed the effects of different emissions to the exhaust gas diffusion,the results showed that the greater the strength of emission lead to the greater the diffusion range and the more obvious the peripheral area.The influences of wind speed,atmospheric stability and different time periods（day or night）on exhaust gas diffusion of single ship are studied,the results showed that strong wind,stable atmosphere and night environment are beneficial for NO₂ diffusion,which have an important impact on the surrounding environment.And the results were applied to multi-ship experiments to study the influence of monsoon climate on ship exhaust gas diffusion in the west area of Shenzhen port,and to simulate the diffusion at night and day in winter,spring,summer and autumn of Shenzhen in 2018.In addition,this paper made recommendations on the atmospheric pollution control according to the characteristic of the diffusion of ship’s exhaust gas.The research results provide a basis for developing emission reductions measures in the port area management and provide relevant experience to other port areas.