| Cyclone flotation technology is an efficient and compact oil-containing wastewater treatment technique.However,it suffers from issues such as poor removal efficiency of emulsified oil droplets and short duration of fine bubbles’action,which limit the further improvement of unit device separation performance.This paper is based on the technical concept of"cyclone flotation+electro-flotation"coupling,aiming to design and develop a compact and efficient cyclone electro-flotation device,and systematically study its separation process and characteristics.In this paper,the separation process of cyclone floatation is analyzed,focusing on the influence of oil droplets and bubble collision probability,effective action time of bubbles,swirl migration characteristics and random dispersion effect on the separation process and characteristics.The analysis results show that bubble quality and hydraulic conditions are the key factors restricting the improvement of oil removal efficiency.Based on the existing theoretical design method of BIPTCFU-III.cyclone flotation device,the BIPTCFU-III.cyclone flotation device with a rated processing capacity of 0.08m3/h was designed,and an indoor experimental platform for separation performance was built,and the influence of working conditions such as split flow ratio,inlet flow rate,gas injection ratio and other working conditions on the oil removal characteristics of the cyclone flotation device was tested and analyzed.The experimental results show that under the optimal working conditions,the lower limit of the particle size of oil droplets treated by cyclone flotation technology to simulate oily sewage is about 15μm.Based on the separation characteristics analysis of cyclone float technology and the results of indoor experiments,the concept of cyclone electric floatation technology combining the advantages of cyclone float and electric float was proposed,and the structural design methods of the main separation tank,cyclone separation zone,spinning transition zone and electric levitation enhanced separation zone of the cyclone electric float device were established by drawing on the theoretical calculation methods of conventional cyclone float,hydrocyclone and electric float structure design,and the calculation of the main structure parameter design and key structure design of the swirl electric float device was established.In order to determine the electrode material,electric field parameters and internal flow field parameters of swirling electric float,experimental research on the characteristics of electric float oil removal was carried out.Firstly,through the characterization of electrode morphology,electrochemical performance,electric field demulsification characteristics and gas production characteristics,the anode electrode and cathode electrode were compared and optimized,and the anode electrode was determined to be"Ru O2-Ir O2-Ti"coated mesh electrode,and the cathode electrode was stainless steel round hole electrode.Based on the determined electrode material and structure,the indoor electric float oil removal characteristic test was carried out,and the effects of electric field parameters,plate spacing,flow field parameters,sewage characteristics and number of electrodes on the treatment of simulated oily emulsion were explored.The experimental results show that the treatment effect is the highest when the current density is 180m A/cm2,the electrode spacing is15mm,and the Reynolds number Re is 15960,and the average oil droplet particle size from 15μm to 20μm can be increased within 1min under different working conditions,so as to meet the requirements of the lower limit of cyclone flotation treatment.Based on the study of the oil removal characteristics of electric float,the optimal flow field parameters and the arrangement spacing of the electrodes are obtained,and then the internal structure scheme of swirling electric float is compared and studied by numerical simulation.The results show that the oil skimmer cylinder and the spinning guide vane can enhance the enrichment effect of swirling electric float on the oil phase and improve the separation efficiency.On the basis of the comparative structure scheme,the influence of the internal swirl field gravitational acceleration and the inner diameter of the steady flow cylinder on the internal flow field and separation efficiency was studied and analyzed.Then,the key structural parameters of swirl electric float are optimized based on CFD+RSM method,and the separation efficiency of the optimized structure is 85.23%.Based on the optimal structural parameters of the swirl electric floatation device,the separation efficiency under different shunt ratios is stable at more than 82.28%.The experimental and numerical simulation research on cyclonic electro-flotation shows that compared to existing cyclonic flotation techniques,the cyclonic electro-flotation technology designed in this study can effectively treat emulsified oil in oily wastewater,further enhancing treatment efficiency.This technology simplifies the process flow of oily wastewater treatment and provides strong support for the green development of oilfields. |
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