![]() ![]() Be careful to prevent excessive agitation that will cause further emulsification instead of resolving the emulsion. Agitation increases the number of collisions of dispersed particles of water and increases the probability that they will coalesce and settle from the emulsion. When turbulence is controlled, however, it can assist in resolving the emulsion. increase the difficulty of removing oil from the produced waterĪgitation or turbulence is necessary to form a crude-oil emulsion.cause high water content in the crude oil and, therefore, the accumulation of unsalable oil and the resultant cost of retreating the crude.reduce the capacity of the treating equipment.cause an excessive need for heat to break the emulsion and for settling time to resolve the emulsion.Using too little treating chemical can fail to break the emulsion and can allow a quick buildup of emulsion and/or sludge. Using too much treating chemical not only wastes the money spent on its purchase, handling, and injection, but also can increase the stability of the water-in-oil emulsion or of the oil-in-water emulsion in the produced water and increase the stability or the volume of the interfacial emulsion and/or sludge. This batch-treatment method normally is used as an emergency measure. Sometimes used for this method of tank treating are railer-mounted units that include: When a tank of wet oil (oil that contains more than the permissible amount of water) accumulates, the tank contents can be treated by adding a small proportion of demulsifier, agitating or circulating the tank contents, and then allowing time for the water to settle in the tank. ![]() More on chemical demulsifiers see Oil demulsifier selection and optimization. (Courtesy of Chemineer-Kenics, Dayton, Ohio.) 6-Kinetic (static) mixer for mixing chemical demulsifier with emulsion. The static mixer is a series of staggered, helically convoluted vanes that use the velocity of the fluid to accomplish mixing.įig. an injection quill (which injects the chemical in the stream at a location that is removed from the wall).In such cases, the following are recommended: Usually, the chemical is injected into a coupling that is welded in the side of the pipe, but when flow rates are low ( < 3 ft/sec) or when laminar flow is encountered, this is not recommended. The larger volume of the mixture can help to mix the chemical more uniformly and intimately with the emulsion. One way to help disperse the chemical throughout the emulsion is to mix a small volume of chemical with a diluent and then to inject and mix the diluted chemical with the emulsion. must displace or nullify the effect of the emulsifying agent at the interfaceįor the oil and water to separate, there must also be a period of continual, moderate agitation of the treated emulsion to produce contact between and coalescence of the dispersed droplets, as well as a quiet settling period.must mix intimately with the emulsion and migrate to all the protective films surrounding all the dispersed droplets.The chemical counteracts the emulsifying agent, allowing the dispersed droplets of the emulsion to coalesce into larger drops and settle out of the matrix. This treatment method is popular because the chemicals are easily applied, usually are reasonable in cost, and usually minimize the amount of heat and settling time required. 1 :ĭehydration chemicals, or demulsifiers, are chemical compounds that are widely used to destabilize, and assist in coalescence of, crude-oil emulsions. The required heat input for an insulated vessel (heat loss is assumed to be 10% of heat input) can be approximated using Eq. Sometimes it is accomplished in a separate section of the same vessel. ![]() Often this is done in a separate free-water-knockout (FWKO) vessel upstream of where heat is added. Because heating a given volume of water requires approximately twice the energy needed to heat the same volume of oil, it is beneficial to separate free water from the emulsion to be treated. The heat input and thus the fuel required for treating depends on the temperature rise, the amount of water in the oil, and the flow rate. For this reason, treating temperatures should be tested so that the lowest practical treating temperature for each emulsion and treating unit or system can be determined by trial. ![]() Emulsions that are produced from different wells on the same lease or from the same formation in the same field might require different treating temperatures. Heating oil emulsions has four basic benefits It reduces viscosity, increases droplets, dissolves paraffin crystals, and increases density between oil and water.Ĭrude oil emulsions with similar viscosity ranges do not always require the same type of treating equipment or the same treating temperature. ![]()
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