Nature Environment and Pollution Technology

Lixin Wei ¹, Xingwang Wang ², Shuangqing Chen ¹, Qiaozhen Li ¹, Linqiong Guo ¹

Affiliations
1 Key Laboratory of Enhanced Oil Recovery (Ministry of Education), Northeast Petroleum University, Daqing, CN
2 SINOPEC Petroleum Exploration and Production Research Institute, Beijing, CN

Abstract

Gravity sedimentation tank is one of the key equipment in the process of oil field sewage treatment, whose separation performance directly affects the treatment efficiency. Polymer-contained sewage is difficult to deal with for its characteristics of large viscous and serious oil-water emulsification. In order to improve the treatment efficiency, we carried out a series of numerical simulation and experimental researches to analyse the separation law and the influencing factors of polymer-contained sewage in gravity sedimentation tank. The results show that flow vortexes exist in the gravity sedimentation tank, and the aqueous phase envelops part of the oil droplets, flows out of the tank from the wateroutlet, thus affecting the treatment efficiency. The oil content and suspended solid content in the treated sewage decrease with the prolonging of the sedimentation time. With the increasing of polymer concentration in the raw water, the diameter of emulsifying oil droplets become smaller and the oil removal rate decreases at the same sedimentation time. By prolonging the sedimentation time appropriately, the treatment efficiency of the polymer-contained sewage can be improved.

Keywords

Gravity Sedimentation Tank, Influencing Factors, Polymer-Contained Sewage, Oil-Water Separation.

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