| With the increasing consume of crude oil in our energy structure, the amount of oil sludge generated in the processes of crude oil production, storage, transportation and refining is rising as well. Owing to its harm to the environment and human health, oil sludge has been enrolled in the "National List of Hazardous Wastes", and non-hazardous treatment is required. Meanwhile, oil sludge is also an energy resource owing to its high concentration of petroleum hydrocarbons, which is economically viable to recover.Oil sludge generated in the process of storage and transportation has the potential of utilization, considering the higher concentration of hydrocarbon. In this thesis, an accurate, rapid determination method of water, oil and solid contents was proposed and investigated with the advantage of onsite determination, by which the value of the oil sludge could be evaluated. The effects of different viscosity reduction measures and different kinds of demulsifiers were investigated and compared to provide a suggestion for the selection of the treatment process. The contents and conclusions are summarized as follows:A proposed method for water, oil and sludge content determination, carbonation-distillation, was studied using the Dean-Stark azeotropic distillation as reference. the accuracy and repeatability of carbonation-distillation method were researched. The experimental results indicated that the absolute deviation of oil content was lower than 2.5%. The values of water content were comparable with the reference ones. Its absolute error was less than 1%. The absolute error of sludge content was lower than 2.5% as well when its content ranged from 2% to 60%. The relative standard deviations of the water, oil and sludge content of storage oil sludge sample were less than 5%, indicating the high repeatability of this method. With the advantages of high accuracy, short time-consuming, solvents-free and easy operation, carbonation-distillation was suitable for the onsite determination of three-phase fraction in the oil sludge.The viscosity properties of oil sludge and different viscosity reduction methods were investigated. The results indicated that oil sludge exhibited the characteristics of high viscosity, which could be attributed to the grid structure formed among solid particles and heavy oil particles. When it was heated from 20 ℃to 60 ℃, the viscosity reduced by 55%. The effect of high temperature on the viscosity reduction was more obvious than that of the lower one. Better performance could be achieved by blending the sludge with a certain amount of organic solvent. When 10% of 120# solvent oil was added to the sample at 20 ℃ and 300 s-1, the viscosity reduced by 90% owing to the reason that the spatial structure of both the oil and the solid phase were destroyed,.The effect of demulsifier type on the combination of demulsification, viscosity reduction and centrifuge of the oil sludge were investigated. The results indicated that P9935 with the highest molecular weight was the best demulsifier, which is synthesized using the phenolic resin as the initiator. The influencing factors on centrifugal separation were further studied by single factor experiments. The results showed that the best demulsification time, centrifugal time, rotate speed, demulsifier dosage, demulsifier concentration were 90 min,30 min,4000 rpm,5% and 0.3%, respectively. The highest dehydration rate of 31.87% and deoiling rate of 76.87% were achieved. In comparasion with ethyl cellulose, the dehydration rate of P9935 was higher than EC. Due to the high content of water and solids in the recovered oil, EC’s deoiling rate was higer than that of P9935. |
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