Research Of Memberane Precision Micro-filtration Technique Of Oily Waste Water

Micro-membrane was used to treat the low permeability oilfield produced water in the study, which meaned to make the filtering water reach the A1 level injection standards. Sintered titanium alloy tube membrane was chosen in accordance with the design of the experimental procedure, and dead-end filtration and cross-flow filtration were compared through their treatment effects.The membranes with aperture of 0.45μm and 5μm were used to treat produced water of Shengli oilfield. Several pressures and different backwashing modes were tried,and the optimum filtration and backwashing parameters were obtained finally. For the membrane with aperture of 0.45μm, the optimum filtration pressure was 0.10MPa, the optimum backwashing mode was backwashing by combining gas and liquid with the optimum backwashing cycle of 40 min, the optimum backwashing time of 4 min and the backwashing pressure of 0.20MPa.The effluent quality could reach A1 level injection standards excepr for the suspension-content, which coud only reach the A2~A3 level injection standards. For the membrane with aperture of 5μm, the optimum filtration pressure was 0.15 MPa, the optimum backwashing mode was also backwashing by combining gas and liquid with the optimum backwashing cycle of 40 min, the optimum backwashing time of 4min and the backwashing pressure of 0.20MPa; But the effluent quality whose oil content and other indicators by and large reached A1 level injection standards, and the suspension-content was unstable, which was worse than that of 0.45μm.Two membranes-flow was used in the study. The membranes with aperture of 0.45μm and 5μm were used in series to deal with the oilfield produced water, and the final filtering water reached the level A1 injection standards, and the optimum backwashing cycle of 0.45μm micro-membrane was prolonged to 80 min. Membrane fouling was a big problem in the application of membrane technology. The experiment also analyzed the causes of membrane fouling, and took cleaning as an efficient method. Chemical cleaning was used when the membrane fouling was serious. Acid and alkaline cleaning method was chosed in the experiment. HCl solution was chosed as the acid cleaning agent and NaOH solution as the alkaline cleaning agent. The optimum cleaning agent concentration and optimum cleaning time on the flux recovery rate were obtained after be investigated.