Research On Key Assessment Methodologies Of Risk And Emergency Response Capability For Oil Spill From Ships

Due to the rapid economic growth,the quantity of crude oil imported from abroad has increased rapidly over the past decades in China.For example,in 2017,the total amount of petroleum products imported by China has exceeded 420 million tons,90%of which is transported by ships.On a daily scale more than 400 oil tankers sail in Chinese coastal waters.In particular,large tankers and Very Large Crude Carrier(VLCC)with the loading capacity up to 300,000 tons are becoming more important than ever before.Accordingly,there is an increasingly global awareness of the potential risk of oil spills.As of now,however,many scenarios have been only conducted based solely on single loading port and/or tanker,and the impact of oil spill at the regional scale remains poorly understood.In addition,few efforts have been devoted to the simulation and evaluation of the emergency ressponse and preparedness capability for oil spills.Therefore,based on the theory of environmental risk assessment and using cutting-edge AIS and GIS grid assessment method,this thesis systematically studies the regional risk zoning of oil spill accident,the amount of oil spill under different scenarios,and the emergency preparedness assessment and rational allocation method.The main outcomes of the thesis are reported as follows:(1)By addressing the nature of the mobility of oil tanker and associated regional risk of point source and the risk of collision closely related to the regional traffic flow and density and the type of the ship,the key risk factors such as regional traffic flow and the loading capacity of the tanker are identified based on the data collecting from the Automatic Identification System(AIS).Subsequently,a risk assessment index system was built by integrating the probability of historical accidents and the degree of environmental sensitivity.Eventually,a grid assessment method for oil spill pollution accidents was established by means of gridding and spatial analysis techniques.This method was exemplified in the Bohai Sea with great success.(2)Based on the statistical results of historical data of oil spill accidents recorded in China and other countries and the analysis of the results of Chinese emergency preparedness for oil spill,chapter two established the method for determining the amount of oil spill under three scenarios,i.e.,the most credible accident,the possible credible accident and the most likely accident.The reasonability of the emergency preparedness for oil spill was discussed while setting the maximum amount of oil spill and the most likely amount of oil spill as the predominant factors.The robustness of this method was verified in the Bohai Sea and the petrochemical area in Guangzhou Port,respectively.(3)The method for reasonably allocating the emergency preparedness is proposed by addressing the degree of the risk for each specific port.The probability of oil spill pollution and the shortest arrival time in the sensitive area were evaluated according to statistical stimulation under stochastic scenarios of oil spill.A risk-index model for oil spill pollution was then constructed in combination with parameters such as the index of environmental sensitivity and the total amount of oil spill.This risk-index constrained the emergency target of oil spill for specific ports.Accordingly,a new assessment model for oil spill response at the regional scale was successfully established.This model can be used to more precisely determining the proportion of emergency preparedness allocated for each port.Furthermore,the application of this model was addressed.Evidently,such newly established model holds great promise for the optimal allocation of regional emergency preparedness.(4)By addressing the advantage and disadvantage of the mechanical recovery,physical absorption and chemical dispersion,chapter four demonstrated the major limitations of the calculation method currently used for emergency preparedness.Afterward,the present chapter proposed a new method for evaluating the capacity of emergency preparedness following oil spill.This method fully addressed the potential influence of evaporation,dissolution and emulsification.Results showed that this improve method can be more suitable for the assessment of emergency preparedness for oil spill in China.Overall,the thesis closely followed the specific characteristics of oil spill in China and the generic strategies of emergency preparedness,and newly proposed a calculation model for key aspects of oil spill risk assessment and emergency preparedness.The major outcomes of the thesis have been recently incorporated into several newly published industrial standards for the transportation,such as "Technical Guidelines on Environmental Risk Assessment of Oil Spills at Waters","Design Codes for Environmental Protection of Water Transportation Facilities",and "Requirements on Preparedness Capabilities to Pollution Accidents at Waters for Ports and Terminals",which provide substantial technical supports for promoting the construction of emergency preparedness for oil spill accidents in China.