Advanced Treatment Of ASP Flooding Produced Water With Ultrafiltration

With the quantity of the oil exploitation promotion,the Primary Oil Recovery and the Secondary Oil Recovery technologies can not meet the demand of the oil quantity.As the development of the Alkali/Surfactant/Polymer?ASP?flooding technologies and the promotion of the application,the treatment of ASP flooding produced water has become more and more important.The ASP flooding produced water has more complicated compositions,higher viscosity and more stable due to the addition of alkali,polymer?HPAM?and surfactant?SDBS?than the other kinds of produced water.Common treatment technologies can not meet the demand which leads to the environment pollution and high operation cost.In this study,ultrafiltration has been employed to treat the ASP flooding produced water.The impacts of transmembrane pressure,salinity and pH on the flux and rejection of membrane has been investigated.The membrane fouling mechanism and cleaning methods were studied at the same time.The optimun operation condition could provide a theoretical basis for the industrial application.The main findings of this study are as follows:?1?Four kinds of wastewater samples?oil solution,HPAM solution,SDBS solution and ASP flooding produced water?have been used to conduct the signal factor experiment.Meanwhile,the impact of TMP,TDS&pH on the permeate flux and rejection of each kind of wastewater have also been investigated.The results suggested that the TMP and pH have significant effects on the filtration process,while the impact of TDS is less significant.The oil and HPAM concentrations in the permeate are less than 10mg/L,the removal are higher than 90%.Even though the concentration of SDBS in permeate is quite high due to its small molecular weight and low concentration which is lower than its critical micell concentration,the permeate still can satisfy the requirements of reuse as rejection water.?2?The Box-Behnken model has been applied to design the 3 factors'response surface experiment.The model for predicting flux reduction was set up through the ANVOVA.The effect of each factor and the interaction between these factors on the filtration was investigated to optimize the ultrafiltration process and the operating conditions.The results showed that TMP has a significant influence on the flux decline and the interaction between the TMP and pH is significant.The optimal operating conditions are:low TMP,low TDS,and neutral condition.The flux reduction prediction model is:J/J0=0.30769-1.90556[TMP]+0.01489[pH]+0.029509[TMP][pH]+2.70912[TMP]²-1.05017×10^-3[pH]²?3?In order to investigate the fouling mechanism and deduce the contaminants of membrane in the ultrafiltration of ASP produced water,scanning electronic microscopy?SEM?,Energy Dispersive Spectrometry?EDS?,Fourier transform infrared spectroscopy?FTIR?and atomic force microscopy?AFM?have been employed to characterize the surface properties of membrane.Through the cleaning experiments of fouling membranes,following conclusions have been made:immersion with deionized water is the best way to clean the membrane used to filtrate SDBS solution;for membrane used to treat HPAM solution,the best way for cleaning is the combination of citric acid solution?mass fraction is0.5%?and NaOH solution?mass fraction is 0.5%?;for the membrane used to treat oil solution and ASP flooding produced water,the use of citric acid solution?mass fraction is0.5%?,NaOH solution?mass fraction is 0.5%?and SDBS solution?mass fraction is 0.5%?can clean well.