| In the preliminary study,the project team found that the "inorganic salt" assisted microwave can significantly improve the oil removal rate of oily wastewater.When the "inorganic salt" acts on the polymer containing wastewater,it makes the polymer form floc,causing secondary pollution of water.As a green,environmental friendly and easy to recover liquid "organic salt",ionic liquid can avoid polymer flocculation.In view of this,this study proposes the method of ionic liquid assisted microwave demulsification,and studies the feasibility of ionic liquid and microwave assisted demulsification.In this paper,the O / W emulsion was prepared according to the polymer content in oilfield produced water,and the stability of the emulsion was evaluated.Then,the demulsification experiments were carried out by microwave,ionic liquid and microwave ionic liquid separately,and the oil removal rate was calculated to explore the demulsification law.At the same time,zeta potential before and after demulsification,interfacial tension between crude oil and active water containing ionic liquid were measured,and Demulsification Mechanism of microwave and ionic liquid was analyzed.On the basis of experimental study,the mathematical model was established and solved by theoretical analysis.The numerical solution of temperature distribution was obtained,and the relationship between ionic liquid,microwave "thermal effect" and oil removal rate was explained.Through experiments and theoretical analysis,the following results are obtained:1.The demulsification effect of single microwave on polymer containing sewage emulsion is not ideal,and the highest oil removal rate is only 34.95%.The potential of the prepared polymer containing sewage emulsion is-55.2m V,and the potential after microwave demulsification is-54.3m V,indicating that microwave radiation can not significantly reduce the stability of the polymer containing sewage emulsion,and has no good demulsification effect.2.The results show that the demulsification rate of ionic liquid does not increase with the increase of the length of alkyl chain.When the alkyl chain is 1-decyl-3-methyl,the lowest demulsification rate is 24.57%,and when the alkyl chain is 1-hexadecyl-3-methyl,the highest demulsification rate is 91.12%,The zeta potential of 1-hexadecyl-3-methylimidazolium bromide decreased from-55.2m V to-2.53 m V.Under the experimental conditions of full concentration,with the increase of concentration,the oil removal rate increased rapidly at first and then remained stable.At 1.25mmol/L,the highest demulsification oil removal rate was88.30%,and the lowest zeta potential was-1.54 m V.The zeta potential of polymer containing sewage emulsion was decreased and the stability of the emulsion was destroyed.3.When the microwave radiation parameters were 600 W,45s,and the concentration of ionic liquid was 1.224mmol/l,the oil removal rate was 92.42%,which was only 1.3% higher than that of ionic liquid alone when the concentration of ionic liquid was 1.25mmol/L.It indicated that the oil removal rate of ionic liquid and microwave demulsification was similar,and there was no obvious positive synergistic effect.4.When 1-cetyl3-methylimidazolyl bromide was added,the oil-water interfacial tension decreased from 0.1713 m N/m to 0.0288 m N/m,which reduced an order of magnitude,indicating that the long alkyl chain ionic liquid had strong interface activity and could significantly reduce the oil-water interfacial tension.5.A mathematical model was established and solved.The results show that the loss factor of polymer containing sewage emulsion decreases with the increase of the concentration of ionic liquid.The temperature of ionic liquid with microwave radiation is lower than that without ionic liquid,and the demulsification and oil removal rate does not increase.The demulsification rule of polymer containing sewage emulsion under the action of micro wave "thermal effect" of ionic liquid was explained. |
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