Surfactants act to reduce interfacial tension between two liquids. IFT exists because the molecules in a liquid have different energies in the bulk phase as compared to close to the interface between a hydrocarbon liquid and an aqueous liquid. Petroleum and chemical streams can contain surfactants as a natural part of the process or as performance enhancer additives. Some of the surfactants present are sodium naphthasulfonates, cresylic acids, naphthenic acids, corrosion inhibitors, biocides, metal scavengers, and emulsion breakers. The higher the viscosity the more difficult the separation.
Fine solids can stabilize emulsions or plug the separating device.
The narrower the difference between the continuous phase and the Density Differences dispersed phase, the more difficult the separation. Free water or other dispersed contaminants cause haze, process equipment fouling, poison catalysts and lead to off-specification product. Removal of these contaminants can improve the economy of plant operation and ensure on-specification product is shipped every time. Common liquid aerosols include condensed hydrocarbons and water in natural gas streams, condensed product in product streams and entrained liquids such as amine and lubricating oils. There are three primary mechanism for the formation of liquid aerosols.