| Oil-tank sludge has high recycling value with its high oil content.Proper recovery and treatment of the oil-tank sludge are of important economic and social significance,since the environmental pollution and the waste of resources can be reduced simultaneously.Based on the above background,the thesis will focus on the phase content detection of the oil-tank sludge for the following two purposes:1)determine the phase content of the oil-tank sludge and provide a judgement basis for choosing the appropriate treatment process;2)determine the value of oil-tank sludge with relative high oil content,so as to properly price them on the market.Therefore,the study on the phase content detection of the oil-tank sludge is of great significance,for lack of the mature methods for oil-tank sludge phase content detection at present.In this study,based on extensive literature review,ultrasound velocity method is employed for detection of the oil-tank sludge phase content.Water content detection of the oil-water mixture is studied firstly,involving the design of the related detection scheme,the hardware,the software and the experiment platform.The appropriate theoretical detection model is selected by experiment,processed with temperature compensation and corrected based on two different regression methods.Using the different influences of temperature on the ultrasound velocity in water and oil,the ultrasound velocity method is for the oil-water-slag mixture,achieving the simultaneous detection of the three phase contents.The main work and innovations of this study include:(1)An ultrasound velocity based water content detection method for the oil-water mixture is proposed.Water content detection method for the oil-water mixture is firstly studied.And a detection scheme is designed using the different ultrasound velocities in water and oil respectively.The Urick model is selected experimentally from several common ultrasound velocity models of the two-phase mixture.And temperature compensation is added to meet the requirement of detection at different temperatures.(2)An ultrasound velocity based water content detection system is designed.In this paper,MSP430F149 is used as the MCU and TDC-GP22 time digital chip is used as the timing unit.A water content detection system is designed based on ultrasound velocity method,which can simultaneously measure the ultrasound velocity and temperature in the sample.Based on the obtained sound velocity and temperature,the water content of the sample can be measured.(3)An improved Urick model for water content detection is proposed.A series of samples with different water content are prepared using crude oil and water,and tested at different temperatures.The Urick model is corrected according to the experiment data adopting the least squares method based multivariate polynomial regression and SVR.The results show great improvements in prediction accuracy when the improved Urick model applied.(4)An ultrasound velocity based phase content detection method for oil-water-slag mixture is proposed.In this paper,the ultrasound velocity method is extended to the three-phase content detection.The relationship model between the water content,the slag content,the ultrasound velocity and the temperature is obtained experimentally.Multiple measurements are carried on the same sample at different temperatures,to obtain a series of sound velocity and temperature data.The data are substituted into the relationship model,to get a set of overdetermined equations.Then the water content and the slag content can be solved by the least squares method.The results show good feasibility of the detection method although the accuracy can be further improved. |
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