Research On Remote Sensing Of Fuel Sulfur Content Based On Infrared Remote Sensing Spectroscopy

Shipping has a huge impact on the concentration of nitrogen oxides and sulfides in coastal areas,especially for huge population.70%of the pollution is concentrated within 400 kilometers.Ship and port pollution is the main factor affecting air quality of coastal cities and regions.Controlling the quality of fuel oil is an effective way to reduce emissions of sulfur oxides and particles from ships.The United Nations International Maritime Organization(IMO)has vigorously promoted various measures to prevent and control marine air pollution in recent years.The 2016 IMO Assembly has adopted the revised MARPOL Convention,deciding that after 2020 ships should use fuel oil with a sulfur content of less than 0.5%m/m worldwide.Under this background,there is an urgent need to carry out research on monitoring technology of sulfur content in marine fuel.Europe and Hong Kong have tried to use mobile sensors to monitor emissions,but the emissions from coastal vessels spread faster,and the monitoring results are greatly affected by meteorological conditions,and each vessel needs to be monitored specifically.Europe is trying to monitor emissions with large drones,which is inefficient and affected by the weather.Optical remote sensing technology can achieve quantitative monitoring of several kilometers by non-contact way,which is an effective technical means for the sulphur content fuel of ships.IMO has developed a method for retrieving the sulfur content of ships using the ratio of the volume fractions of flue gas SO2 and CO2,which has laid the foundation for the remote measurement of the sulfur content of ship fuel.The remote sensing technology is divided into active and passive types according to the presence or absence of active light sources.The active method requires the installation of active light sources,which cannot meet the needs of marine ship monitoring.The passive methods mainly include differential absorption technology and infrared remote sensing technology.The differential absorption method is limited to non-cooperative targets,while infrared remote sensing technology is not limited by the target.Hyperspectral infrared remote sensing technology is widely used in the monitoring and analysis of gases,such as monitoring applications in fixed emission sources or relatively fixed backgrounds,but for ship emissions in time-changing backgrounds in motion,especially complex sea conditions and radiation transmission environments Under remote sensing monitoring,the related basic and technical issues must be resolved.The hyperspectral identification method under the complex time-varying background of shipsDuring the remote sensing period of ship smoke emission,the background changes fast,and the target gas is interfered by the atmosphere.The atmospheric spectrum changes with different humidity and atmospheric thickness,so an adaptive target feature extraction method is needed.The traditional bright temperature spectroscopy method defines the concentration range values of the atmosphere and the target in the prior information,and fixes the shape of the atmosphere and the target spectrum in advance.In actual applications,the atmosphere and the target spectrum are not exactly the same as the set values,so the traditional bright temperature spectrum The method lacks adaptability.A method of infrared spectrum feature extraction based on LASSO is researched,which fully utilizes prior information,by simulating group of atmospheric and target spectral data sets,using LASSO's variable selection advantages to adaptively select a priori spectrum,and realizes adaptive deduction of background spectrum.2.Correction of atmospheric radiation transmission effects in low-elevation sky in marine environmentThe acquired spectrum needs to be converted to radiance through radiation calibration.The instrument linear function(ILS)also has a broadening effect on the spectrum.It is necessary to correct the influence of these instrument parameters on the acquired spectrum.An ILS correction method based on atmospheric absorption spectrum is proposed.Simulated spectrum matches with the measured spectrum.In the marine environment,the atmospheric temperature and humidity change rapidly.The measured spectrum includes the rapidly changing atmospheric spectrum.The local temperature and humidity profiles are obtained in real time using ECMWF(European Center for Medium Range Weather Forecasts)data,and the instrument measurement is calculated in conjunction with the instrument ILS function.The atmospheric spectrum improves the accuracy of atmospheric correction.3.Established the first fuel oil sulfur content model using infrared hyperspectral data,and carried out experimental verificationA FTIR remote sensing system was designed,and control acquisition software was written to display the sulfur content of the ship under test in real time.A radiation calibration method under external field conditions is proposed.The built-in black body is used to achieve rapid calibration under external field conditions.The external black body calibration coefficient is transferred to the built-in black body in the laboratory,and the built-in black body emissivity is calibrated by multi-temperature data.accuracy.A quantitative evaluation experiment was carried out at Shanghai Maritime University,which tested the system's remote sensing capability under different fuel sulfur content and different working conditions.The experiment proved that the system can detect 0.36%m/m fuel.Field remote sensing experiments were carried out in Yantian Port in Shenzhen,Waigaoqiao Port in Shanghai,and Huizhou Port in Guangzhou,and compared with oil pumping tests and drone sniffing tests.The inversion results are in good agreement.This thesis carried out the research of infrared spectroscopy remote sensing technology of marine fuels,starting from the principle of gas remote sensing,analyzed the FTIR remote sensing system and key parameters,broke through the weak gas signal feature extraction method under the changing background,established the Fourier transform infrared spectrometer remote sensing system,Quantitative evaluation and port experiment verification were carried out,and the influence factors and improvement directions of remote sensing were analyzed.Through the above research,it provides technical means for port ships to use fuel content remote sensing,fills the gap in the application of hyperspectral infrared remote sensing technology in this field,and provides strong support for the realization of ship fuel clean automatic monitoring.