Study On Collision/coalescence Forces Between Droplet And Film In Coalescence Separator

The separation and demulsification of produced fluid with high water-cut is one significant procedure in on-field processing of oil-water-gas,among which the corrugated plate separator is widely applied due to its advantage of combining the mechanism of gravity and coalescence separation.In separation process,oil droplets first spread out into oil film on coalescence plate,the upcoming droplets then interact with the formed oil layer.Consequently,the dynamic collision and coalescence process between oil droplet and oil film in aqueous solution is the key mechanism in oil-water separation.Most of the mechanism study on droplet-film coalescence process is from macro-perspective to study the appearances,whereas the micro-perspective analysis and studies on forces between oil droplet and film in oil-water dispersion system is urgently required to better understand the separation mechanism and improve on-field separation efficiency in the future.In this paper,the scanning probe microscopy technique is utilized to realize the dynamic interaction experiment between micro-scale size droplet and nano-scale thick film.First,the fundamental characteristics of interaction forces between droplet-film,droplet-droplet and droplet-surface are compared,and forces between droplet-film under different engagement conditions,viscosity settings,and droplet sizes are analyzed.Secondly,the effects of aqueous solution on droplet-film interaction force such as salinity,p H values and polymer concentrations are investigated.By quantitatively analyzing the measured spinning droplet interface force and collision forces between droplet and film,the effects of aqueous environment on droplet stability and interface deformation are studied.Results show that increasing salinity or changing p H values can decrease the stability of droplet due to charge screening,but the existence of co-polymers can increase spacial hinder force through interface adsorption thus can hinder coalescence.At last,the joint effects of p H and co-polymer on droplet-film interaction forces are investigated,and results show that solution p H values can affect the adsorption and arrangement of co-polymer on interface and inter-layer.