on the separator(s) or electrostatic dehydratorĪdditives are injected by a piston or diaphragm proportioning pumps.on the production unit inlet manifold or,.The demulsifier injection points are placed: This is by far the most commonly used method. This system is usually applied on wells produced by hydraulic pumping with the purpose of preventing emulsion from forming due to turbulence. It may still be used if an out-of- specification crude, contained in a stock tank, has to be treated again following an incident during routine heating operations (injection pump break down, etc.). This very old method is rarely used nowadays. Three types of treatment can be considered: The principle consists of injecting a determined quantity of additives at one or several points on the crude oil production system. EQUIPMENT FOR THE INJECTION OF CHEMICALS.The solvents used are mainly of two types: ethylene oxide, propylene oxide copolymer carbonate derivatives,.ethylene oxide and propylene oxide copolymer esters,.polyoxypropylate, polyoxyethylate phenol-formol resins,.polyoxypropylate and polyoxyethylate diamines,.ethylene oxide – propylene oxide copolymers,.To our knowledge, there are a dozen groups of active chemicals for demulsification: In general, an additive consists of one or several active elements and one or more solvents. The “bridging” theory was developed by LAMER, MICHAELS, HEALY to explain the flocculation of colloidal solids, and it would appear logical to extend this idea to cover emulsions.
If, moreover, the interfacial films are destroyed by the surfactant, coalescence can occur. If this “bridging” effect takes place, it explains the flocculation of water droplets. The long chain macromolecule adsorbed a the surface of a drop of water can, for instance, extend its action to the mass of the solution, which will allow the demulsifier to connect up with another drop. The chemicals most frequently used are a combination of high molecular weight synthetic polymerics and surfactant detergent. To destroy the interfacial films (which means increasing the water-oil interfacial tension) so that the water droplets can coalesce and then.To wet the solids present in order to disperse these particles in one of the.To favour the grouping of water droplets (flocculation).Hence, a demulsifier which is intended to break a water-in-oil emulsion must be soluble in oil. This property is a function of the migration speed of the demulsifier in the continuous phase in the direction of the oil water interface and of its capacity to become adsorbed preferentially at the interface or to interact with the emulsifier present. Procedures to break tight water-oil emulsion involve usually a combination of chemical and physical processes.Ī demulsifying agent should have the following characteristics: Which mainly make use of the temperature and/or electrostatic field effect. Emulsion breaking procedures can be classified in three categories:īy adding active molecules (demulsifiers) at a very low concentration (from a few ppm to a few dozen ppm). This study covers only the treatment of water/oil emulsions.