溢油乳化过程的受激布里渊散射特性及其在海洋溢油检测中的应用研究

Spilled oil is one of the most serious marine environment disasters, the emulsification of spilled oil could change the properties of oil and is not conducive to remove effectively the spilled oil. The accurately forecast of the spilled oil and the emulsification process has not been solved at present, the key problem is the lack of effective methods for discriminating the spilled oil and the emulsification process, and this is also an urgent issue for monitoring the spilled oil pollution of ocean. In this project, the relationships between the emulsification of spilled oils and the spectra will be researched by investigating the characteristics of UV-VIS-NIR spectra and stimulated Brillouin scattering (SBS) of crude oil, gasoline, kerosene, diesel, and lubricating oil, respectively. The spilled oil and its emulsification process can be effectively discriminated through using SBS spectra to measure the elastic modulus of spilled oil. For the detection of underwater suspended oil, a dual-wavelength SBS method has been proposed, in which the suspended oil can be detected by measuring the viscosity of seawater based on the range gating technology of Brillouin lidar. The proposed method in this project is not only can detect the ocean spilled oil, but also can monitor the temperature and salinity of seawater synchronously. Four national invention patents have been declared based on the related technical methods of this project. We believe that, the research results possess potentially application value for improving the monitoring accuracy of spilled oil pollution.

溢油是破坏海洋环境的重要灾害之一，溢油乳化会使油的性质发生变化，不利于溢油的有效清除。目前对溢油及其乳化过程的准确预测一直没有得到解决，问题的关键点是对溢油乳化过程缺乏有效的判别手段，这也是海洋溢油污染监测亟待解决的问题。本项目以常见油种（原油、汽油、煤油、柴油及润滑油）作为研究对象，通过对不同油种在不同乳化阶段的紫外—近红外光谱响应特性及受激布里渊散射特性的研究，分析溢油乳化与光谱特征的关系，并用受激布里渊散射测弹性模量的方法对水面溢油及其乳化过程进行有效判别。针对可能存在的水面下悬浮溢油，提出用双波长受激布里渊散射方法并结合激光雷达的距离选通技术，通过测量水面下海水粘度的变化实现对水下悬浮溢油的探测。本项目提出的技术方法不仅可以探测海洋溢油，也可以对溢油海域的海水温度及盐度信息进行同步监测。相关技术方法已申请4项国家发明专利。研究成果将对提高海洋溢油污染监测的准确度具有潜在的应用价值。

溢油是破坏海洋环境的重要灾害之一，目前对溢油及其乳化过程的准确预测一直没有得到解决，问题的关键点是对溢油乳化过程缺乏有效的判别手段，这也是海洋溢油污染监测亟待解决的问题。本项目主要针对溢油乳化过程的近红外吸收特性、受激布里渊散射、拉曼散射特性进行研究，主要内容包括：（1）本项目根据米散射理论，仿真研究了在不同的折射率、颗粒半径以及入射波长下的溢油乳化液的散射截面和散射相函数，并详细分析了折射率、颗粒半径以及入射波长对溢油乳化液的散射截面和散射相函数的影响。（2）利用拉曼光谱分析技术研究了柴油中生物柴油的浓度变化规律。实验采集了柴油、生物柴油及柴油/生物柴油混合物的拉曼光谱，利用采集到的拉曼光谱信息，获得了燃油中的分子结构信息。结合主成分分析法和偏最小二乘回归分析法对燃油进行了定性定量分析。（3）以柴油、航空煤油、生物柴油作为研究对象，分别测量了不同种类、不同乳化程度的溢油乳化液样品的拉曼光谱及近红外吸收光谱。研究发现，随着乳化时间的增加，溢油乳化液样品的拉曼光谱的拉曼强度逐渐减少，溢油乳化液样品的近红外吸收光谱的吸光度逐渐增加。（4）实验测量了不同条件下燃油中受激布里渊散射频移。结果表明，柴油和生物柴油的受激布里渊散射频移都随温度的升高而减小，柴油/生物柴油混合物的受激布里渊散射频移随生物柴油浓度的增大而增大；柴油中的声速随温度升高而线性减小，生物柴油中的声速随温度升高而非线性减小，柴油/生物柴油混合物中的声速随生物柴油浓度的增大而呈现指数式增长。（5）以石油、柴油、汽油、航空煤油四种油类产品作为溢油污染对象进行检测研究。采集不同油品的受激布里渊散射信号，得到各自的受激布里渊散射频移。结果显示，随着温度或盐度的增加，油污染水体的受激布里渊散射频移都会增加，但随漂浮的油品种类不同，其频移也存在差异；利用受激布里渊散射技术对不同油水比例的乳化油进行鉴别，随着油水比例的变化，受激布里渊散射的信号也会发生变化，可以分辨出乳化油的种类。