Study On Membrane Process Used For Treating Oilfield Produced Water Of Low Pemeability Oilfield

In order to improve the injected water quality, the ceramic membrane filterdevice and ultrafiltration membrane filter device were used for treating oilfieldproduced water in this paper.In the text ceramic membrane used for treating oilfield produced water, firstly,the influence factors of membrane fulx was discussed with distilled water as feedliquid. The results showed that, membrane flux was unchanged over time, increasedlinearly as transmembrane increasing, increased gradually as temperature andcrossflow rate increasing, but the effect of crossflow rate is less. Secondly, analyzedthe effect of different operation parameter on membrane flux by treating oilfieldproduced water, the results showed that transmembrane pressure and temperatureacted more greatly. The optimal operation condition were transmembrane pressure0.16Mpa, temperature50℃and cross-flow5m/s when the quality of the effluentwas achieved with A1standard. Meanwhile, the constituent of membrane resistanceand the cleaning method of membrane fouling were discussed. The results showedthat the intrinsic resistance contribute the most of total resistance,irreversibleresistance and partial reversible resistances contribute almost the same, thereversible resistance contribute the less. Result also showed NaOH combined withHNO3was helpful to recover membrane flux, the membrane flux can be back to95%after chemical cleaning.In the text ultrafiltration membrane used for treating oilfield produced water,With modified fiber ball filters as organic ultrafiltration membrane pretreatmentdevices, with the pressure type hollow-fiber membrane was made by modifiedmembrane material. The test analyzed the effect of different operation parameter onmembrane flux, oil and suspended solid removal efficiency by ultrafiltrationmembrane, the cleaning method of membrane fouling. The optimal operationcondition were reflux ratio50%, temperature50℃and backwash cycle25min whenthe quality of the effluent is achieved with A1standard. Meanwhile, using SEM andEDX analysised the membrane fouling. The results showed that the new membrane sufface were smoothly and the membrane pore were clearly visible. The fouledmembrane showed that the pollution phenomena were serious, it can not see anysigns of membrane. Infered that the membrane suface foulants possibly consist ofCaCO3, MaCO3and Al2O3. Result also showed NaOH combined with HNO3washelpful to recover membrane flux, the membrane flux can be back to95%afterchemical cleaning.