Abstract: In offshore platform produced-water treatment systems,gas flotation tanks are difficult to maintain,leading to reduced oil removal efficiency as service time increases,which significantly increases the cost of produced water treatment.To improve the treatment effeciency,it is proposed to retrofit the unit into an electroflotation tank that can provide certain oxidation and sterilization effects on the produced water while maintaining oil removal performance,thereby reducing the burden on subsequent processes.However,at present there is no industrial implementation of electroflotation tanks,and related research is scarce.To investigate the feasibility of the electroflotation tank retrofit,steady-state simulations of the oil removal process in an electroflotation tank were carried out using Fluent software to exa mine the effects of current density,residence time,and other parameters on the oil content of the treated water.The simulation results show that the oil content at the water outlet decreases with increasing residence time and with increasing current density,and the latter effect is more obvious.The electroflotation tank can achieve optimal performance at a current density of 150 A/m² and a residence time of 20 minutes,under which the oil content is reduced from 1 000.00 mg/L to 62.54 mg/L,meeting the discharge standard.This result demonstrates the feasibility of retrofitting an electroflotation tank and can provide technical reference for upgrading aging flotation units on offshore platforms.

Key words: offshore platform, produced water, oil content, electroflotation tank, Fluent software