A novel bench size model coalescer: dehydration efficiency of AC fields on water-in-crude-oil emulsions

Abstract

We describe herein the design of a small ac electrostatic model coalescer for investigating coalescence efficiency of water in oil emulsions. The function of the model coalescer is tested on emulsions with different water cuts. In the coalescer, coalescence takes place in a couette flow in the bulk emulsion. The electric field has a high utilization factor, and the electrodes are insulated to avoid drop charging. The setup allows for independent setting of retention time and shear rate of the emulsion. Temperature can be adjusted up to 80 °C, and AC voltage level, frequency and shape can be varied. Efficiency is measured optically and by checking speed of water precipitation. Several parameters have been studied to determine their influence on the electrostatic dehydration process of water-in-crude-oil emulsions. Temperature, wave form, water content, droplet size but also rotational speed were found to play an important role in the process according to what was expected theoretically.

Mitigating Noncoalescence and Chain Formation in an Electrocoalescer by Electric Field Modulation

“…Extensive work has been carried out in the past, exploring a range of voltages and types of waveforms, to improve the efficiency of electrocoalescers. The literature on the effect of waveforms, − frequency of the AC field, ,,− and strength of the electric field ,,,,, on electrocoalescence suggests sensitive dependence of droplet coalescence or chain formation on these parameters. Often, studies on electrocoalescence have conflicting claims on both optimal frequency as well as the effect of frequency on the performance, indicating high sensitivity to the experimental conditions and parameters.…”

A Self‐Powered and Efficient Triboelectric Dehydrator for Separating Water‐in‐Oil Emulsions with Ultrahigh Moisture Content

“…Comparison of d) the initial moisture content and e) final dehydration rate obtained in this work with others. [ 14,39–45 ]…”

“…The design of an FR-TENG enables the polyvinyl chloride (PVC) film on the rotor soft to contact with the nylon film on the stator. Compared with other [14,[39][40][41][42][43][44][45] tightly frictional TENGs, the FR-TENG has less resistance torque between the rotor and the stator. Therefore, it is easier to harvest environmental energy, such as wave energy, wind energy, and ocean current energy.…”

“…When the moisture content increases and exceeds the phase inversion concentration, the water-in-oil emulsion turns into the oil-in-water emulsion. [39][40][41] It is well known that oil is usually a good insulator. Water is insulated in the ideal situation, but in practice, it is conductive.…”

A Capacitance-base System Design for Measurement of Crude Oil Moisture

“…Because of having different dielectric constants, a change of water content in crude oil may lead to a change in its capacitance value, which may convert to a variation of an oscillator's phase angle [23] or a change to the oscillation frequency of a non-contact frequency modulated oscillator's output [24]. Although the contact measurement methods have great accuracies, the indirect measurements of the capacitance value correspond to a poor range, which is limited by the oilwater ratio of the tested crude oil [25,26].…”