Study On Movement Behavior And Recovery Technology Of Oil Spill On Sea Surface

In the process of oil and gas exploitation and transportation,possibility of marine oil spill accidents does exists,which causes serious harm to the marine ecological environment and production construction,and results in huge losses.The treatment of oil spill on the sea surface can be carried out in two stages: oil spill recovery and oil water separation.According to the principle and characteristics of free surface vortex,the purpose of oil spill recovery can be achieved by using oil collecting cap,and the cyclone separator can be improved to meet the requirements of rapid and efficient separation of oil and water mixture.On the one hand,the study is on the basis of carrying vortex phenomenon and Rankine compound vortex model theory.A small scale oil spill recovery equipment was designed and manufactured.The property of free surface vortex method for oil spill recovery was verified by laboratory experiments.FLUENT software was used to simulate the process of oil spill recovery by free surface vortex,and the processing performance under different working conditions was analyzed.For the numerical calculation of the vortex on the free surface,the results obtained by using the RNG k-ε model had good authenticity.For the calculation of the free surface,the VOF model had good processing results.On the other hand,according to the working principle of cyclone separator,combined with various influencing factors in the marine environment,existing technology was refined.An axial inlet cyclone separator was designed and manufactured,which was useful to complete the preliminary separation of oil and water with the recovery structure,and carried out an in-depth study on its working performance.The studies have shown that:1.The main factors affecting the structure of the vortex are the depth of the bottom outlet,the flow rate and the diameter length,while the other non-main factors can be properly simplified in the establishment of the geometric model.2.The tangential velocity distribution of the vortex conforms to the Rankine composite vortex theory,and the radius of the vortex core can be found according to the tangential velocity.The closer the position is to the bottom outlet,the greater the axial velocity will be,and there will be up-down flow exchange outside the vortex core.The radial velocity is larger near the free surface and at the bottom of the flow field.When oil spills are distributed on the water surface,the velocity changes are gentle,and the velocity combination in all directions proves the carrying characteristics of the vortex on the free surface.3.The free surface vortex is more suitable to deal with the oil spills of various components on the sea surface.The vortex is still feasible under the slight disturbance of the Marine environment.With the help of other equipment,the free surface vortex method has a wide range of adaptability to the flow rate.4.In the process of oil spill recovery,the oil phase flow has a multi-stage characteristic.The high frequency fluctuation stage of the recovery process can better reflect the main characteristics of recovery,and the experiment can be guided according to the high frequency stage of numerical simulation.5.Axial inlet cyclone separator forms swirl flow field with mixed liquid passing through guide vane,and realizes oil and water separation through different centrifugal force.Experiments showed that the separation efficiency of the cyclone separator can exceed 70%,and the separation efficiency has minor changes under different oil amounts,species and ocean wave loads.The mixed liquid can be separated efficiently in general.