Whatever the user chooses, he or she must guard against using the thinnest oil found on the market to avoid the problem of inadequate oil film strength and thickness. They can use a jet of oil (oil spray) or convey the oil mixed with compressed air in the form of an oil fog-also called oil mist. Users can heat the oil or avoid oil rings and other risk-inducing lube application methods by using smarter means. Thick oils are more viscous and may not readily flow into the bearings. Figure 1 illustrates where these motor oils fit in comparison to the industrial oil designations used today. But thinner oils, perhaps SAE 10, can help prepare a vehicle for winter driving. The proper economic balance of heat and chemicals requires evaluation.Some will know from their experience with automobiles that thicker oils, such as Society of Automotive Engineers (SAE) 30, are more appropriate for warm summer months. When the treating problem is seasonal, some emulsions can be resolved successfully by adding more chemical demulsifiers during winter months. On the other hand, treatment, especially heating, might not be required in the warmer summer months. Emulsions usually are more difficult to treat when the air is cooler-e.g., at night, during a rain, or in winter months. In some geographic areas, emulsion-heating requirements vary in accordance with daily and/or seasonal atmospheric temperatures. Using less heat and a little more chemical, agitation, and/or settling space can obtain the most economical emulsion treatment. If properly done, heating an emulsion can greatly benefit water separation. This will minimize evaporation losses and reduce fuel cost however, it also will increase the vapor pressure of the crude, which might be limited by contract. If the oil is above inlet-fluid temperature when it is discharged from the treating unit, it can be flowed through a heat exchanger with the incoming well fluid to transfer the heat to the cooler incoming well fluid. Perhaps more importantly, the small gas bubbles are attracted to surface-active material and, hence, to the water droplets thus, they tend to keep the water droplets from settling and might even cause them to be discharged with the oil.įuel is required to provide heat, and so the cost of fuel must be considered. In vertical emulsion treaters and gun barrels, some liberated gas could rise through the coalescing section, creating enough turbulence and disturbance to inhibit coalescence. The gas that is liberated when crude oil is treated also might create a problem in the treating equipment if the equipment is improperly designed. In special cases, increased heat might cause the density of water to be less than that of oil. For heavy crudes ( < 20☊PI), which normally are treated above 180☏, heat might have a negative effect on the density difference. Because most light oils are treated below 180☏, the effect of heat on gravity is beneficial. In general, at temperatures below 180☏, adding heat will increase the density difference. Heat also might increase the density difference between the oil and the water Molecular movement, which helps coalescence by causing the dispersed-phase droplets to collide more frequently.Į.g., dissolve paraffin crystals), or might enhance the action of treating chemicals, causing the chemical to work faster and more thoroughly to break the film around the droplets of the dispersed phase of the emulsion. Viscosity should be < 7 cSt for desalting. 12L recommends that crude oil be heated so that its viscosity is 50 cSt for dehydration. If the viscosity is unknown at any temperature, the chart’s curves may be used. Viscosity that is known at one temperature can be approximated at other temperatures by drawing a straight line parallel to the curves already on the chart. If a crude oil’s viscosity is known at two temperatures, it can be approximated at other temperatures by drawing a straight line along those temperature/viscosity points on the chart. Crude-oil viscosities vary widely, and the curves on this chart should be used only in the absence of specific data. 1 can be used to estimate crude-oil viscosity/temperature relationships. Which allows the water droplets to collide with greater force and to settle more rapidly. 1.3 Heat also might increase the density difference between the oil and the water.1.2 Heat might deactivate the emulsifier.1 Heat reduces the viscosity of the oil.
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