Formation of water chain under the non-uniform AC electric field

Electrocoalescence is widely used to separate water from crude oil in petroleum indus -try. However, the electric field often forces water droplets distributed in chain shape, thus improving the danger of short circuit by bridging electrodes. To understand the mecha-nism of water chain phenomenon, an in-situ observation experiment were conducted to investigate the effect of voltage, frequency, water content and surfactant concentration. The results showed that the water chain length and growth rate of droplet diameter var-ied synchronously with the voltage and frequency. Additionally, the water chain length and growth rate of droplet diameter increased firstly and then decreased with the initial water content. The initial droplet diameter decreased with the surfactant concentration, which inhibit formation of water chains and coalescence. As the surfactant concentration reached a critical value, the initial droplet diameter remained constant, while the inhabita-tion of micelle for the coalescence strengthened with the surfactant concentration. These conclusions are helpful to understand the mechanism of formation of water chains. (c) 2021 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.

Automated summary

Electrocoalescence is commonly used in the petroleum industry to separate water from crude oil. In this study, an in-situ observation experiment was conducted to investigate the factors influencing the formation of water chains. The results showed that voltage and frequency had synchronous effects on the length of water chains and the growth rate of droplet diameter. The initial water content initially increased the length of water chains and the growth rate of droplet diameter, but later decreased. The addition of surfactant reduced the initial droplet diameter, inhibiting the formation of water chains and coalescence.