Detection And Identification Of Oil Slicks On The Sea Surface Based On Laser-induced Fluorescence

With the rapid development of the world economy and petroleum industry,the increase in petroleum demand has promoted the development of the oil transportation,and at the same time has increased the risk of oil spill involving ships,ports,and waterways.The accurate detection and effective identification of oil species are of great significance to the formulation of oil spill cleanup treatment plan,guarantee of shipping safety,and protection of ecological environment.As an active remote sensing technology,laser-induced fluorescence(LIF)technology overcomes the problems of temporal and spatial resolution and realization cycle in oil spill emergency response,and can realize the detection and identification of oil slicks with high sensitivity and fast time response,as well as related sensors carrying platforms which are flexible,and has been developed and applied to some extent in the emergency handling of oil spill accidents.However,the mechanism of LIF of oil slicks is still unclear,and the quantitative relationship between the chemical composition of oils and the fluorescence characteristics has not been established.Therefore,it is difficult to achieve the fluorescence spectra inversion of the oil slicks,the precise identification of oil species and the accurate detection of thin oil films.In response to these problems,this paper conducts research on mechanism research,identification methods,and a detection sensor development and application.The main innovation achievements as follows:(1)Based on the fluorescence generation mechanism and fluorescence characteristics of the organic components in the oil,the fluorescence spectra composition method of oil slicks based on polycyclic aromatic hydrocarbons(PAHs)is proposed,which constrncts the composite fluorescence spectra of different oil species and solves the problem of fluorescence spectra reconstruction of oil slicks.Based on the composite fluorescence spectra of different oil species,this thesis compares the difference between the measurement fluorescence spectra and composite fluorescence spectra of different oil species,and provides a quantitative analysis method for the identification of fluorescence spectra differences.Based on the excitation-emission matrix spectroscopy(EEMS)of different oil species at different concentrations,a method for extracting characteristics of fluorescence spectra is proposed,and it is clear that 300-400 nm fluorescence spectrum is the characteristic band of oil slicks fluorescence detection and identification,which provides a basis for the selection of fluorescence spectra characteristic wavelength band in oil slicks detection and identification.(2)By analyzing the effects of PAHs on the fluorescence spectra of crude oils,the problem of oil species identification caused by the similarity components and fluorescence spectra is solved,and a crude oil species identification method based on the main fluorescence peak of PAHs is proposed.Gas Chromatography-Mass Spectrometer(GC-MS)technology is used to analyze the types and relative contents of PAHs in different crude oil samples.According to the position characteristics of the main fluorescence peak of a single PAH,the relationship between the fluorescence intensity and the relative content of PAHs is analyzed,and the oil species identification model is constructed within the fluorescence intensities in 350-380 nm corresponding PAHs relative content,realizing the effective identification of different crude oil species.(3)According to the fluorescence spectra characteristics of different oil species,a compact coastal-mounted oil slicks fluorescence detection sensor was designed and implemented.We design a fluorescence filter device based on a band-pass filter(300-400 nm)and a condenser,and use relative fluorescence intensity(RFI)and data rate of change(DCR)as early warning parameters for oil slicks detection.The detection of micron-level oil film in the laboratory environment has been carried out,and field experiments and applications have been carried out to meet the daily oil spill monitoring needs of coastal oil storage bases and large oil ports,and effectively guarantee the production and transportation safety of ports.Based on the LIF,this thesis has carried out the research on the accurate detection of oil slicks and the identification of oil species.Based on the research on the fluorescence generation mechanism and fluorescence characteristics extraction of the oil slicks,the method of identifying the crude oil species is proposed and the oil slicks fluorescence detection sensor is developed,and verify the effectiveness of the proposed detection and identification method through experiments and applications.This research is of great significance to ensure the safety of maritime transportation,and it also provides technical methods and detection equipment for the application of LIF in oil spill emergency treatment.