Research Of Equipment To Detect Water Content In Petroleum Based On NIR Technique

Online measurement of water content in petroleum is a significant procedure during oil mining and oil refining process. But present techniques are based on electrical principles; they achieve a low performance-to-price ratio and also have other disadvantages. An instrument based on NIR technique is developed to measure the water content in petroleum and will be discussed in this thesis.Activated H2O molecules absorb near infrared ray at specific wavelength range. A water content measurement instrument is developed based on this theory. Firstly, the thesis addresses the works on analysis and designs of optical path system, detection circuit, and fiber probes. Secondly, a photo-electricity circuit using Lock In Amplify (LIA) theory is developed, which can detect weak signal emitted from an LED light source. The data collecting and processing software in Visual Basic is developed specifically for processing experimental data. And then, according to the parameters of this circuit, a reliable experimentation is mapped out. The water-content-detecting experiments are conducted as follows. The conclusions indicated that, NIR technique has unique advantages over other methods to measure water content in petroleum. The feasibility of the system has been proved. The system's performances also meet the expected targets closely. The precision, the fidelity and the reliability of this system, however, need to be improved in the future. At the end of this paper, an improved scheme of project is proposed aiming to solve the existing problems.Finally, another experiment about remote online measurement with fiber routes has been carried out. According to the results, the insufficiencies of fiber method are summarized. An improved proposal is put forward.