Mechanistic Study of Water Droplet Coalescence and Flocculation in Diluted Bitumen Emulsions with Additives Using Microfluidics

Abstract

Synthetic crude oils derived from mined oil sands processed via the Clark hot water extraction process do not meet current specifications for pipeline transport and are corrosive to upgrader equipment by virtue of the high residual water content (2–5%) and salts. Formulated chemical additives used in this process can improve the oil quality by accelerating and enhancing the separation of water from oil. The identification and selection of these formulated additives is typically based on performance data collected in field testing for each component or blend. Herein, two methods are reported to study the effect of chemical additives on the phase separation behavior of water in diluted bitumen emulsions prepared in microfluidic devices. First, water droplets in diluted bitumen were created in the presence of chemical additives and the kinetics of droplet coalescence were compared for various additives and concentrations. Second, using a custom-made device geometry, water droplets in diluted bitumen were formed and aged prior to the addition of chemical additives. The treated droplets were observed to calculate the kinetics of droplet coalescence. The frequency of coalescence events was the same order of magnitude in both studies. The effectiveness of various additives can be determined by measuring the coalescence time, which is dominated by film drainage in the case of the best chemical additives.

Microfluidic tools for studying coalescence of crude oil droplets in produced water

“…Both model oil-inwater [21][22][23] and water-in-oil systems [24][25][26] were previously reported in the literature. In the petroleum science, however, the focus of microfluidic applications is rather shifted towards fluid analysis [27][28][29] and very few papers concerning separation can be found 30 . While in microfluidics the effect of gravity is negligible, it still allows to systematically study the merging of drops during flow, in contrast to other techniques that study coalescence in more static conditions 31 .…”

Microfluidic method for determining drop-drop coalescence and contact times in flow

“…Coalescence time of gas bubbles in water containing various sodium halides was studied by Wang et al 28 . Nowbahar et al reported a microfluidic device for studying destabilization of water-in-diluted bitumen emulsions after adding a de-emulsifier 29 . The measurements were performed in a long serpentine channel without flow, and the coalescence times were twothree orders of magnitude longer than in the previously cited literature.…”

Elaboration of the Demulsification Process of W/O Emulsion with Three-Dimensional Electric Spiral Plate-Type Microchannel

“…The active method is mainly implemented by using an applied electric field, a sound field, or the like [24,25,26,27]. Some researchers [16,28] employed both methods together to get a better separation efficiency. John S. Eow proposed that the droplet coalescence process can be described in three stages: Droplets approaching each other, the process of film thinning/drainage and film rupture leading to droplet-droplet coalescence [5].…”