Study Of Detection And Recognition Technique Of Oils Pollutant In Water Based On Fluorescence Mechanism

With the development of economy, the exploitation scale of the fossil oil on land or on sea bed has been enlarged. The carrying trade by ship has been flourished and industry and agriculture have made great progress. The emission amount of the industrial effluent and sanitary waste and agricultural drain and other rubbish are increased on an annual basis. There is a lot of remained petroleum product in the waste water. It caused the pollution of the environment. The mineral oil is leaked out to the water. It has been seriously affected the health of the human. So, it is of great importance to identify the species of the mineral oil in the water and determinate the density of the mineral oil to the environment protection.At the present time, existing detection method of oil pollution ad mineral oils mainly includes the nephelometric and ultrasonic method, light scattering method, gravimetric method, ultraviolet absorption method, no dispersive infrared absorption method, infrared spectrophotometer method, and chromatography and fluorophotometric method and so on. The measurement accuracy of them is not good enough to the micro content measurement of the oil because of the measuring principle of them. They are not portable and can not identify the species of the mineral oil.In this paper, the method to identify the species of the micro content oil in water based on the fluorescence spectrum detection is studied. A design scheme of the identification of the mineral oil in water based on the combination of the optical fiber sensing and the spectral detection and the pattern recognition of the fluorescence has been proposed. It can realize the fast detection and the species identification of the mineral oil.Starting with the basic principle of fluorescence measurement, the fluorescent characteristic was researched by the experiment. The optimally detection parameter of the wavelength range of the excitation and the emission spectra has been determined. The linear relation between the density of the mineral oil and the fluorescence intensity has been determined. The spectral character of the optical source and the transfer characteristic of the fiber and the dichroism of the dispersion element and the spectral response characteristic of the CCD has been researched. The optical source, the fiber-optics probe, the little CCD spectrometer, the high speed data acquisition and the signal process of the system have been designed. The highly active collection and the transfer of the weak fluorescence signal have been researched. The CCD spectrum detection system based on the CPLD has been researched. The CPLD realized the auto data acquisition under the control of the chip.The pattern recognition technology of the mineral oil has been researched. It aims to extract the data which can reflect the intrinsic characteristic of the mineral oil from the spectral data. The KPCA and the ICA was used separately to extract the characteristic of the spectral signal of the mineral oil in water. The Naive Bayes and the KNN and the SVM and the WNN were used separately to classify the characteristic extracted by the KPCA and ICA. The discrimination of them was compared and the method of the identification of the mineral oil has been determined.The mathematic model to quantitative analyze the oil content in water based on the Lambert-Beer law has been researched. The linearity correction principle was used to realize the single constituent quantitative analysis of the mineral oil. It combined the derivative spectrum method to realize the quantitative determination of every component in the multi-component mixed oil without the prophase dissociate. The performance of the system was appreciated.