Separation Performance Research Of Liquid-Liquid Cylindrical Cyclone Separator

Liquid-liquid cylindrical cyclone separator has simple structure,but flow distribution in the separator is complicated and split ratio as well as overflow components are hard to control,which hinders the practical application of the separator.In this paper,liquid-liquid cylindrical cyclone separators with different structures are designed,and the separation performance of the cyclone are investigated experimentally from the aspects of structural parameters and operational parameters,with optimal dehydration ratio being the evaluation index.The main research contents and conclusions are shown below:In this paper,the design and manufacture of oil&water mixing device and cylindrical cyclone separator have been carried out.Four kinds of inlet flow patterns are defined based on different superficial velocities of oil and water.The optimal dehydration ratio was employed as an index to evaluate the separation performance of the separator,and Shimadzu UV-2600 spectrophotometer was utilized to measure the change of oil content in the underflow.Based on the separation phenomenon in oil/water separation process and the changes of water content in the overflow port,the abrupt change point of oil content was determined,and therefore figures out the optimal dehydration ratio of the separator.The effects of structural parameters on the separation performance of the liquid-liquid cylindrical cyclone separator were studied.The tapered flow area of the cone section can supplement the angular momentum loss caused by friction and improve the radial migration efficiency of oil droplets,which is beneficial to the separation of oil and water.The increasing height of the overflow section will cause the increase of the friction loss,which is not conducive to the discharge of the oil core;while the increasing height of the underflow section stabilizes the oil core,and therefore further promote the oil-water separation effect.The orifice vortex finder can eliminate the short circuit flow to a certain extent,improve the flow field inside the cylindrical cyclone,and promote the discharge of the oil core.The optimal separation performance of the cylindrical cyclone separator occurs,when the length of the cone section is 305 mm,the height of the separator is 20 D,and the orifice vortex finder is arranged inside.The effects of operational parameters on separation performance of the liquid-liquid cylindrical cyclone separator were studied.The increase of the inlet mixing velocity,on the one hand,helps form a sufficient strength of the centrifugal field,improving the separation performance;but on the other hand,it will lead to the fragmentation of oil droplets,shorten the residence time,deteriorating the separation performance.Experimental results show that when the inlet mixing velocity is 0.3 m/s and 0.6 m/s,the cylindrical cyclone separator presents a good separation performance.Modified liquid-liquid cylindrical cyclone separator has a wide applicability to the inlet water content.When the inlet water content is higher than 70%,the cylindrical cyclone separator shows a good dehydration capacity.According to the analysis of pressure drop,the pressure drop at inlet and overflow is the main pressure drop of cylindrical cyclone separator,while the orifice vortex finder and inlet mixing velocity are the main factors affecting pressure drop.Based on the experimental study,it can be concluded that when the inlet water content is higher than 70% and inlet mixing velocity is 0.6 m/s,the modified cylindrical cyclone separator can improve the separation performance with less energy consumption,and thus expand the application of the liquid-liquid cylindrical cyclone separator.