Process Optimization Of Cyclonic Flotation Separation For Oily Wastewater

Because of the reaction process's complexity of oil-gas-water boundary,the research of the cyclonic flotation process is still in the exploratory stage.Based on cyclonic flotation evaluation unit,the passage studies low intensity cyclonic flotation process with experiment from three respects of centrifugal acceleration,property of wastewater,diameter compatibility of bubble and oil droplet,which is of great importance for completing cyclonic flotation theory and industry application.The main contents and conclusions are as follows:In view of low intensity cyclonic flotation theory,the passage puts forwards two views:the effect of swirl field on the performance of the cyclonic flotation process is biased towards the collision process,diameter compatibility of bubble and oil droplet is the basic factor to determine adhesion property.From the point of view of collision and adhesion,the passage puts forwards four kinds of effects:central collision,inertia separation,drainage adhesion,emulsification dissipation,and discusses the specific role of four effects on the oil removal performance of low intensity cyclonic flotation process.In view of centrifugal acceleration and property of wastewater?oil droplet diameter,oil content?,the passage studies their effects on the flotation performance.The best centrifugal acceleration is 8-12 times acceleration of gravity g,which is the equilibrium region of central collision,inertia separation,drainage adhesion,emulsification dissipation,and central collision and inertia separation paly the leading role.The impact of oil droplet diameter on collision has priority to the impact on adhesion and emulsification,the smaller oil droplet is more suitable for higher intensity cyclonic flotation.With the limit of bubble's flotation ability,the larger oil droplet is more suitable for flotation with limits.Oil content influences collision condition of bubble and oil droplet,the effect of oil droplet diameter and oil content is relevant,excessive high oil content causes the deterioration of collision condition's orderliness.In view of diameter compatibility of bubble and oil droplet,the passage studies their effects on the flotation performance.For 15.62-43.54?m oil droplet and 23.25-56.78?m bubble,the flotation ability of bubble decreases with diameter increasing.The impact of bubble size on flotation is mainly reflected in the turbulence near the bubble's face and adhesion stability.The nature of the compatibility of bubble and oil droplet is the compatibility of collision and adhesion ability.With oil droplet size increasing,the subsidy requirement of flotation ability is reducing,then the size range of bubble which is effective for flotation is increasing,however,the extent of range's expansion is decreasing.The diameter compatibility of bubble and oil droplet is not sensitive to oil content,the size range of bubble which is efficient for flotation with certain size's oil droplet stays stable.when oil content is 200-1500 mg·L^-1.Based on the mechanism analysis and experimental results,the passage puts forwards the evaluation criteria of low intensity cyclonic flotation.In the respect of centrifugal acceleration,for the oil droplet which diameter is 25.64-43.54?m,the centrifugal acceleration should be8-12 g.In the respect of size compatibility,for 18.62-43.54?m oil droplet,the upper limit of bubble could be defined with the d_bubble-max/d_oil=0.64-1.40.In the respect of oil content,low intensity cyclonic flotation is suitable for treating wastewater with low oil content.