Fluid Dynamics Simulation And Experimental Research Of Filtration And Backwashing Process Of Oilfield Canister

Filtration backwashing process is widely used in oilfield wastewater treatment.Effluent quality depends on the performance of filtration and backwashing of the filtering tank.In practical engineering application,there are some problems,such as unsteady filtration performance,the raise of backwashing pressure,and the loss of filtering material,which leads to worse filtration performance and non-reaching standard effluent.This paper studied specifically on the laboratory experiment of the filtration backwashing agitator blade impeller and fluid mechanics simulation,and investigated the practical effect of the filtration backwashing process by the modification of the field process.Through the study of the problems of existing quartz s and filter,hydraulic dynamic backwashing filter was developed.55° was the most ideal for a single wheel performance under no-load condition;and 45°/55 for the combination wheel performance under infinite loading condition.FLUENT software was applied to accomplish CFD analysis of the whole process of backwashing,from impeller startup to the periodic steady-state flow,and it took about 25 seconds.The water mainly flowed through four openings on the upper part,and flow rate was basically unchanged at each entry position in a cycle;When the flow regime was steady,maximum flow rate could be up to 2.38 m/s at the exit.In the mixing area,streamline was disordered but its shape was basically the same as the blade.Streamline changed sharply along with time,leading to the fluctuation of the maximum speed.Due to the effect of hydrostatic pressure,the pressure on the blade increased with the increase of the depth of the water.Under different mixing angle at different time,pressure would fluctuate due to the change of the water flow rate,and the blade pressure fluctuation range of the same height was within 1 kpa.CFD simulation could vividly show the changes of streamline and pressure,which was convenient to study the internal flow condition in the process of backwashing.In the field experiment,the rotating impeller agitator blade was improved,and the backwashing parameters and modes were optimized.The stirring action of rotating impeller agitator blade at backwashing is realized because of this kind of transformantion,which could reduce the corner of oil drain.The water collectiondistribution equipment also optimized the water distribution of filter tank.It was beneficial for the shattering of the harden layer to reduce the loss of the filter ing material.Moreover,on the basis of a large number of experimental data,the appropriate filtration and backwashing intensity was determined.In this paper,the mechanism analysis of hardening problems of the filtration backwashing tank was performed,the fluid mechanics simulation and the actual application provided the basic support for promotion and practical application of the filtration backwashing technology.