Membrane device for treating oilfield produced water for reinjection and treating method

Abstract

The invention relates to a membrane device for treating oilfield produced water for reinjection and a treating method. The device comprises a feed liquid tank, a series of separator main bodies, built-in membrane separation elements of the separator main bodies, a backlash tank, a cleaning tank and a pump. The oilfield produced water with oil spots enters separating devices through a precipitation tank and the pump; a clear liquid after membrane separation is in accordance with a reinjection index of oilfield reinjection water, and used for the reinjection; and waste water with the oil spots on the concentrated liquid side returns to the precipitation tank. When a permeating flux decline of a filtering unit module is set to be 80% of an initial value, the backlash course is started. A whole system is totally enclosed so as to prevent the water from being contacted with the outside to bring in new pollution; the quality of dischargws products on the clear liquid side can be ensured; the products are high-temperature resistant and acid and alkali resistant; the clear liquid side of a ceramic membrane is high in flux; the treating capacity is high; the separating effect is good; the effluent quality is stable; a ceramic membrane filtering system is easy to operate, short in technological process and high in automation degree, and lowers the cost and investment; a cleaning period is long; and a flux restoration ratio can reach above 90% after cleaning.

Description

technical field [0001] The invention relates to a device and method, in particular to a method for removing impurities such as residual oil and suspended solids in oil production water, and provides an economically feasible and technically satisfactory treatment of oil field production water for the oil field sewage treatment industry to be used for recycling. Note the membrane device and treatment method. Background technique [0002] At present, most oilfields in my country are exploited by water flooding. As the oilfields enter the late stage of high water cut, the amount of water produced by some oilfields has increased significantly, and the composition of the produced water is complex. In addition to the substance, it also contains various agents such as chemical additives and lubricants, resulting in serious emulsification of the produced water, stable structure and difficult handling. [0003] But for low-permeability layers and ultra-low-permeability oil layers, A1 ...

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Problems solved by technology

[0002] At present, most oilfields in my country are exploited by water flooding. As the oilfields enter the late stage of high water cut, the amount of water produced by some oilfields has increased significantly, and the composition of the produced water is complex. In addition to the substance, it also contains chemical additives, lubricants and other agents, resulting in serious emulsification of the produced water, stable structure and difficult handling

[0003] But for low-permeability layers and ultra-low-permeability oil layers, A1 grade water quality requires the median particle size of suspended solids to be ≤1μm, suspended solids to be ≤1mg / L, crude oil to be ≤5mg / L, and average corrosion rate to be <0.076mm / a. The conventional treatment methods of produced water (such as gravity sedimentation, cyclone centrifugation, air flotation and fine filtration, etc.) are difficult to meet this requirement

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