Experimental Research On Technology For Desalination Of Oilfield Produced Water Contained Polymer

With the tertiary Enhanced Oil Recovery(EOR) technology furthering carrying on and developing,polymer flooding and alkali-surfactant-polymer (ASP) Compound Flooding have been applied in many oilfields. A large amount of oil wastewater contained polymers and oil is produced during oil exploring with polymers in Da qing. At present, the water treatment techniques which only by use of conventional sendimentation and filtration processes being adopted in oilfields produce especial higher salinity water, which can't be used to confect polymer solution directly so that ultra-filtration (UF) membrane and electrodialysis and UF- electrodialysis are used in order to treat the water, as a result of improving the water quality and reducing mineralized degree in the effluent. In this situation, if polymers are re-added back into stratum again, reuse of water resource will be possibly realized.The experimentation was put in practice at the second oil extraction factory in Da qing. The raw water was treated by use of conventional sendimentation and filtration processes and the quantity was 400L/d with the characteristic was summarized as suspension content of 8.2～15.5mg/L, oil content of 2.6～8.7mg/L and polymer content of 210～390mg/L, respectively.The results demonstrated that both suspension content and polymer content of wastewater treated by UF were less than 1.0mg/L with the removal efficiency of 85%～90% for suspension. Radium median of suspension cannot be detectable in the effluent of UF. The removal efficiency of oil and polymer reached 80%～95% and 85%～90% respectively, while the removal efficiency of COD was up to 80%～95%,but the desalination efficiency was very low. According to the analysis aiming at the contaminants on the membrane surface, a preferable membrane refreshing method, which was that a mixed solution contained 1.0%OP-10 and 0.5%NaOH was used to refresh the UF system, was found, and membrane resumption can the achieved using the method.A small-scale electrodialysis equipment was designed and manufactured. Throuh experimentation, the optimal parameters for the operation of the equipment are: working voltage is 10V, the dense water flowrate and the fresh...