A Study On Demulsification Of W/O Emulsion By Inorganic Micro-filtration Membrane With Degree Of Vacuum As Transmembrane Pressure

In this paper, making a search for method of high efficiency and generalservicedemulsification of W/O emulsion fomed liquid membrane separation technique treated withcontaining phenol waste water as purpose, plentiful literature about demulsification technologywere consulted, comprehend analyzed and derived that new pattern membrane demulsificationtechnology have the characteristic of high efficiency and versatility compared with traditionaldemulsification technology, but which also have the disadvantage, such as membrane flux issmall, efficiency is decrease after membrane implement running a long time. Objective in thiswork is enhance demulsification effect through improvement and overcome apart of shortageexistenting membrane demulsification processes by means of effective method. Demulsificationof W/O emulsion by inorganic micro-filtration membrane was studied.Firstly, in this paper, study on demulsification technology of W/O emulsion by inorganicmicro-filtration membrane with degree of vacuum as transmembrane pressure. The effect ofmembrane material, membrane pore size, the ways of transmembrane pressure, membrane surfacecross-flow velocity and temperature on demulsification processes were studied mostly and theappropriate parameters were obtained. For the first time, originality emulsion made withimpinging stream-rotating packed bed(IS-RPB) was used in the study of membranedemulsification processes. Based on the characteristic of inorganic micro-filtration membranetexture, bring forward firstly degree of vacuum as a way of transmembrane pressure in membranedemulsification processes, which was experimentalized and analyzed its mechanism of higheffective demulsification. Study show, with the originality emulsion drop size is ranged from5μm to 25μm and average emulsion drop size is about 11μm, the Al2O3 membrane with poresize around 2.0μm owed high demulsification ratio and high permeate flux in thedemulsification process. Different operation pressure and different pressure ways have differentdemulsification ratio and permeate flux. With the increasing of transmembrane pressure, thedemulsification ratio increase and then decreases gradually, but permeate flux increase always.Demulsification effect with vacuum transmembrane pressure is better than that with outsidetransmembrane pressure. With the increasing of membrane surface cross-flow velocity, thepermeate flux increase nonlinearly, but when membrane surface cross-flow velocity exceed 4m/s,the permeate flux increase no evidence. With temperature rising, emulsion viscosity reduceand liquid membrane surface tension descend, which led to demulsification ratio lightlydescend and permeate flux increase evidentely. So optimal temperature range is from 308K to315K.Secondly, in this paper, fouling mechanism and intensify demulsification of this processwere discussed and studied. several part resistance and its ratios of this process were determinedby resistance model, fouling mechanism of this process was discussed and effective membranepollution control technique was determined. For the first time, applying new-style enhancementtechnique by rotary tangential flow in tubular membrane micro-filtration to membranedemulsification technique, and its intensifying effect of demulsification was studied and theenhancement mechanism by rotary tangential flow in tubular membrane demulsification wasanalyzed. The while, energy consuming at different ways was analyzed and compared. Studyshow serious of resistance of the demulsification process'with vacuum transmembrane pressureand axial flow and vacuum transmembrane pressure and rotating tangential flow respectively aredeposit adsorbed layer and membrane itself. Energy consuming analysis demonstrates that rotarytangential flow tubular membrane demulsification is a high efficiency technology of membranedemulsification separation, its energy applying efficiency is higher than the axial flow's. At testconditions, the stable energy efficiency of rotary tangential flow tubular membrane vacuumdemulsification are 3.35 times of axial flow tubular membrane vacuum demulsification's.Finally, in this paper, the back-flush technology, methods of membrane clearing andreused of the oil phase after demulsification were studied. Study show the gas-liquid back-flushtechnology can control membrane fouling efficiency, and it can keep high permeate flux, whichmay be 8.4 percent higher than before. Alkali and tap water are applied to cleaning thecontaminative membrane at the optimal operation condition. At first, with alkali liquor cleaning, itshould be more than 30 minutes, and then, with tap water cleaning, it should be more than 10minutes. The pure water permeate flux could return to 80 percent of the originality, and theemulsion permeate flux may be approximately recover. The oil phase after demulsification maybe multiple resued.