| Oilfield produced water contains a large amount of emulsifier and inorganic salt ion.It is a kind of oily emulsified wastewater which is difficult to be treated.The researchers have done a lot of works for the separation of oil-water.Membrane separation method,as a new separation method in modern times,develops rapidly for its unique advantages.However,the cost of membrane is expensive and the membrane will be seriously polluted,which limits its industrial application.As one of the membrane modification methods,dynamic membrane technology has attracted wide attention because of its effectiveness in separation of oilfield produced water.At the present stage,the research on the treatment of oil-water with dynamic membrane is limited to the experiment,and lacks the research of related mechanism.In this paper,the application of dynamic membrane in oil water separation process is discussed by combining experiment and mechanism research.Firstly,according to the characteristics of oil-water mixtures containing emulsifiers,a molecular dynamics model of "oil-emulsifier-water interface" was established by molecular simulation method to study the influence of emulsification factor on oil-water emulsification.The study found that the four kinds of commonly used industrial emulsifier(SDS,SDBS,SLS,SP-80)in the presence of oil-water system,the optimal conditions for the demulsification is emulsifier SP-80,0.25g/L,30?.Na+,Ca2+ and Al3+ can promote the demulsification and with the higher valence cations,which promote more demulsification.For SDBS and SDS,in the aluminum ion concentration is greater than 0.75g/L,will react to the emulsifier and generate precipitation,promote demulsification process.Secondly,zirconium dynamic membrane is prepared in single channel tubular ceramic membrane to study emulsification factors and separation operating factors of oil-water separation effect on the dynamic membrane.By orthogonal experiment the optimal separation conditions is temperature 50?,operating pressure 0.14 MPa,flow 120L/h,emulsifier SDS,emulsifier concentration 1.0g/L.The study found that the permeation flux increased with the increase of operation pressure and flow rate and then gradually stabilized,with the increase of temperature increases first and then decreases;when the other conditions are the same,four kinds of emulsifier system flux from big to small order is SP-80>SDS>SLS>SDBS;with the increase of emulsifier concentration,steady permeate flux decreased gradually;Na+? Ca2+ and Al3+ can promote the flux in a certain degree,and the higher valence cations,the stronger the effect.For SDBS and SDS,when the concentration of aluminum ion is greater than 0.75g/L,will react with the emulsifier in the system to produce precipitation material,so that the flux increases dramatically.Thirdly,on the basis of single channel dynamic membrane separation experiment,the effect of tubular seven channel dynamic membrane on oil-water separation was investigated.The study found that single channel and seven channel flux change with each factors is basically the same,and under the same conditions seven channel flux has been less than single channel,this is due to the middle channel of seven tube dynamic membrane has weak permeat power and the external impact of the six pipeline flux penetration caused by flux decline.Nevertheless,the seven channel membrane separation process is more suitable for industrial applications due to its large amount of processing and easy processing of components.In summary,the method combined with experiment and mechanism study of dynamic membrane separation process of oil-water separation process,from micro to macro analysis of dynamic membrane,provide a theoretical basis for dynamic membrane separation in the field of industrial water. |
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