A perforated electrode design for passivation reduction during the electrochemical treatment of produced water

Abstract

Produced water refers to the water that is generated when oil and gas are extracted from the ground, and it usually includes the natural water layer within the reservoir (formation water) as well as the injected water. The generation of these large amounts of produced water represents a major environmental and economic challenge to the Oil and Gas Industry. Although many studies have attempted addressing this challenge, there has not been any significant development in the treatment of produced water, and most of these studies have achieved limited success. This work introduces a novel electrocoagulation cell for the treatment of produced water, with the aim of reducing electrode passivation, which has always been considered as a bottleneck in the electrochemical treatment of contaminated water. The main goal of the study is to develop an effective perforated electrode design that can reduce cathode passivation and consequently reduce energy consumption. The novel cell design has been tested and optimized for the treatment of produced water to reduce the concentration of the major organic contaminants in the water. The contaminants reduction efficiency of the proposed design was evaluated and benchmarked with multiple cell configurations. The perforated electrode was superior to other configurations and effective in mitigating passivation, reducing the energy consumption by about 70 % compared to the typical plate electrode. The cell performance was optimized, using response surface methodology, and then operated continuously to evaluate the electrocoagulation efficiency. The new cell design achieved a steadystate reduction of the organic contaminants in the produced water by up to 97 %, 98 % and 95 % for TOC, TPH and O&G, respectively.