An improved method and process unit for desalting petroleum crude oils in which a portion of the stable emulsion layer which forms in the desalter vessel is withdrawn from the desalter and diluted with a liquid diluent, typically oil or water or both to destabilize the emulsion which is then separated into separate oil and water phases. The test result showed that asphaltene in crude oil causes the raising and abnormal of crude viscosity. Be adapted to the electric desalting process from the lightweight to heavy crude. During mixing, salt content in oil is washed with the water and a wo emulsion is formed. The type and size of the desalter that is used is dependent upon a number of fundamental factors such as pressure, temperature, fluid viscosity and flowrate, as well as customer requirements relating to maximum salt allowed in the product oil stream. A crude oil desalter is a device used in petroleum refineries to remove inorganic salts, water and sediment from the incoming petroleum crude oil feedstock before it is refined.
Desalting is commonly performed using electrostatic separating tanks, 50100m 3, operating at relatively high pressures of about 20 bar, and temperatures up to 160 o c. Oxygen occurs in different forms in oxygenbearing resinous substances. Electrical desalter is the typical method of crudeoil desalting. The crude oil is heated and mixed with sweet water and often demulsifiers in order to dilute the salt, and the emulsion is separated in the electroseparators. Experts of cic stella design office define technological modes dehydration and desalting of oil, depending on the initial oil content of the water and salts.
Alotaibi the history of crude oil desalting dehydration plant ddp has been marked in progressive phasesthe simple gravity settling phase, the chemical treatment phase, the electrical enhancement phase and the dilution water phase. Oil produced in most oil fields is accompanied by water in the form of an emulsion that must be treated. Crude oil desalting the desalting of crude oil is a process that does not have a high profile, but is vital to the operation of the modern petroleum refinery. Electrical desalter is the typical method of crude oil desalting 2. Modelling and optimising of crude oil desalting process.
The compatibility of asphaltic crude oil with demulsifiers in the electric desalting process was studied in this paper. Flexibility in desalting operations for opportunity crudes. Desalter howebaker international desalter insulator. The equipment used for the removal of salts, suspended solids and water soluble trace metalsslits, iron oxides, sand etc. Crude oil treatments training course petroknowledge. Electrical dehydrators crude oil dehydration and desalting. Electrical desalter is an effective method in crude oil desalting. For the following reasons, it is of utmost importance to reduce the amount of salt in the crude before processing the crude in the crude.
Cn101037612a crude oil pulsing electrical desalting. The salts containing some of the metals that can poison catalysts are dissolved in the water phase. Crude oil desalting the presence salts in crude oil the water droplets are so small that they cannot settle by gravity. Pdf article open access a comprehensive electrical. Today their products are exported to singapore, jordan. Natco electrodynamic desalter electrostatic desalting. Using our wellestablished crude oil management concepts, the xeric program provides your refinery with a comprehensive systemwide analysis, effective chemical treatment technologies, and a broadbased design for mitigating heavy oil processing problems. Mature crude oil fields are often prone to high water cuts and high content of fines. Electrical dehydrators is a complex technological equipmenttherefore it requires an individual approach in the design. It is recognized that an electric field can be used to mix the dilution water and the crude oil at high efficiencies in the course of the emulsification stage. The crude is introduced below the electrodes to create the maximum oil residence time for improved dehydration fig. In addition, this water normally contains dissolved salts, principally chlorides of sodium, calcium, and magnesium.
Almost all refineries now use electrostatic desalters. Improvement of crude oil desalting process in refinery. Therefore, the mixing valve element is replaced with electric mixing. Pdf optimum temperature in the electrostatic desalting. Highly efficient dehydration and desalting of crude oil from mature. Crude oil often contains water, inorganic salts, suspended solids, and watersoluble trace metals. First of all, the electrical conductivity of crude oil is a material parameter and differs with crude type. Desalting involves mixing heated crude oil with washing water, using a mixing valve or static mixers to ensure a proper contact between the crude oil and the water, and then passing it to a separating vessel, where a proper separation between the aqueous and organic phases is achieved. Whether it is at the site or at the refinery that will be discussing here and the crude oil desalting process becausethere has been lot of the development in the crude oil, desalting, but normally because just to requirement of the process we are the two stage crude oil desalting. A kind of crude oil pulsing electrical desalting technique.
The concentrations of pahs may increase during electric desalting of heavy oils compared to light oils. Among these, pahs with low ring numbers are more easily transferred from crude oil to the wastewater during electric desalting. Electrical supply taps 824 1236 kv 8003,000 volts inch line voltage transformer secondary voltag e spacing grids kva rating. Crude oil desalterdehydration howebaker international. In chemical desalting, water and chemical surfactant demulsifiers are added to the crude, which is heated so that salts and other impurities dissolve or attach to the water, then held in a tank to settle out. Pretreatment of crude oil by ultrasonicelectric united. The salt is dissolved in the water in the crude oil, not in the crude oil itself. This is the reason why they are typically applied in upstream applications. This petroknowledge training course provides a detailed understanding of theories and technologies involved in crude oil treatment, petroleum crude formation, production, phase separation process, emulsion theory formation, crude oil desalting, stabilization and the mechanism through the technology to destabilize and separate water from oil in. Desalting electrostatic coalescers are also applied for desalting in order to reduce the crude s salt content. The emulsion then enters the desalter where it is subject to the action of an intense electric field. When this operation is performed at a refinery, an electric field across the. The participants will also learn about electrical desalting, as well as other types of desalting processes that are found in the oil industry today.
By lowering the surface tension between two fluids in the case of desalting oil and water, they are allowed to mix. Modelling and optimising of crude oil desalting process 20110217t11. Furthermore, the electrical conductivity is strongly dependent on temperature and on. First, a decrease in oil density and vis cosity implies a significant increase in the settling rate of. The desalting is usually the first process in crude oil refining. Crude oil conductivity crude oil quality association. Structure and character of asphaltic molecules make them easily gather and associate with each other at the oil water interface and finally form a viscoelastic interfacial. Pdf article open access a comprehensive electrical model.
Us5080779a methods for removing iron from crude oil in a. Electric desalination petroleum refinery,petroleum. The refiners often wash the crude oil with fresh water, add chemical demulsifier, and use electrical desalting vessel to remove the added water and most of the inorganic contaminants from the crude oil 1. Crude oil desalting using hydrocyclones pdf free download. Crude oils also contain a great variety of heteroatomic chemical constituents, comprising of crude oil. Electric desalting and dewatering of crude oil emulsion based on. Psulphur, oxygen, carbondioxide, nitrogen and trace metals. Heavy oils contain large amounts of polycyclic aromatic hydrocarbons pahs with different ring numbers. The recommended process conditions for the thorough desalting of typical crudes are summarized in this paper. Crude oil pretreatment desalting petroleum refinery. On day one, participants will obtain a general overview of the types of oil desalting systems.
Purpose of crude oil desalting crude oil introduced to refinery processing contains many undesirable impurities, such as sand, inorganic salts, drilling mud, polymer, corrosion byproduct, etc. Furthermore, these fine droplets have on their surfaces big asphaltene molecules with the fine solid particles coming from sediments, sands or corrosion products. After separation by gravity settling, crude oil can be desalted by following the. Crude separated from the second desalter has substantially diminished iron content compared to crude fed to the first desalter. Physical and chemical properties of crude oils and their. Desalting is a waterwashing operation performed initially at the production field and thereafter at the refinery site for additional crude oil cleanup. An increase in process tempera ture has two opposite effects. After the crude oil is pumped out from the oil tank, it is mixed with fresh water and demulsifier in proportion, heated to the specified temperature, and sent to the firststage desalting tank. This article focuses on the use of electrostatic desalters to produce a dehydrated, desalted crude oil with a low sediment content. Desalting is the first refining process applied to crude oil. Crude oil desalting technology is utilised to remove residual salt to meet these requirements.
A surfactant will reduce the surface tension between two fluids. In the process description section, the desalting process. Our surfactants have long hydrophobic segments which efficiently break down crude petroleum emulsions. The large population of small water droplets and fines forms very. Desalters provide more protection to costly refinery equipment than any other single piece of process hardware. The lowintensity electric field is then used to treat the bulk emulsion and interface, whereas the highintensity electric field between the electrodes is used for removal of the final traces of water and smaller droplets. Desalting of crude oil is an essential part of the refinery operation. As a first step in the refining process, to reduce corrosion, plugging, and fouling of equipment and to prevent poisoning the catalysts in processing units, these contaminants must be removed by desalting. Xeric heavy oil demulsifiers baker hughes, a ge company. Engineering design guideline crude unit desalter system. The desalter removes contaminants from crude oil by first emulsifying the crude oil with chemicals and wash water to promote thorough contact of the water and oil.
Dehydrators dehydration and associated salt removal using high voltage electrical grids to achieve 0. It has been observed that good mixing allows for appropriate salt removal from oil. Crude oil dehydration and desalting longdom publishing sl. Voltage within the desalter is 16,000 to 30,000 volts ac. The bilectric hf desalter begins the desalting process by adding lowsalinity washwater upstream of the mixing valve, generating a uniform mixture of smallsize brine and washwater droplets throughout the crude slate. In the case of waterincrudeoil emulsions, a balanced optimum formulation is. Electrical desalting is the application of highvoltage electrostatic. The salt content after the desalter is usually measured in ptb pounds of salt per thousand barrels of crude oil. The presence of chlorides in crude oil leads to hydrogen corrosion of equipment and necessitates a thorough desalting in electric desalting units elous. Desalt challenging crude slates such as lowapi and conductive crude oil. Salt and water content specifications are even more rigid because of their negative effect in downstream processes due to corrosion, and catalyst deactivation. How engine lube oil system works in diesel electric locomotives. Desalter by sparklet engineers pvt ltd squartech solutions. Pdf optimal processing parameters of electrostatic crude oil.
Optimization of operating parameters of oil desalting in southern. Bilectric hf highfrequency ac desalter schlumberger. When this operation is performed at a refinery, an electric field across. Natco electrodynamic desalter electrostatic desalting technology for crude oil combines five technologies to provide a compact, reliable, and effective desalter with a single vessel. Process group offers a range of technology options to cover most typical processing requirements related to crude oil desalting. Comprehensive chemical analysis and characterization of. A desalter is a process unit in an oil refinery that removes salt from the crude oil. Engineering design guideline crude unit desalter system rev1. Study on the compatibility of asphaltic crude oil with the. Then the crude oil distillation various stream from the atmospheric. The invention belongs to petrochemical complex technology of electric desalting technical field, what relate generally to is a kind of crude oil pulsing electrical desalting technique. The process removes salt, water and solid particles that would otherwise lead to operational problems during refining such as corrosion, fouling of equipment, or poisoning of catalysts. Electrostatic coalescers are applied as the final separation step to break up emulsions and reduce the remaining water fraction dehydration. If crude oil is left untreated, when it is processed in a refinery the salt can cause various operating and maintenance problems.
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