Electrical desalination problem?

The mixing valve adjusts the mixing intensity of crude oil and water. The greater the mixing intensity (that is, the greater the pressure difference), the better the desalination effect. However, the emulsification of oil and water will be serious, and there will be a lot of oil in the water. In severe cases, the oil and water may not separate, so the pressure difference must be adjusted according to the oil and water conditions, especially when the crude oil is replaced. Demulsifiers are very sensitive to the properties of oil and water and are very specific. The dosage is not critical. The key is to choose the right demulsifier.

The electric desalting mixing valve is used to adjust the mixing degree of crude oil and demulsifier, but not excessive mixing to avoid emulsification of crude oil. In the early days, a mixer was used for mixing, but the mixing intensity of the mixer was fixed, which was not suitable for the mixing intensity requirements of various crude oils with different salt contents and demulsifiers. The amount of demulsifier added and the pressure drop of the electric desalting mixing valve are related to the properties of the crude oil, salt content, desalting water injection amount, etc. The requirements of various crude oils vary greatly from factory to factory. This post was last edited by bayi81 on 2009-3-27 12:57 ]

This depends on the actual situation, that is, after dewatering, the water content, salt content, and oil content of the sewage are analyzed to specifically determine the mixing intensity. Generally, there is a range. The higher density crude oil is 0.9111-0.9659g/cm3, the mixing pressure difference is 30-80kpa, the smaller density crude oil is 0.8017-0.9042g/cm3, and the mixing pressure difference is 50-130kpa.

The mixing pressure difference is generally controlled between 0.055 and 0.08MPa. The pressure drop of the mixing equipment is a sign of the dispersion strength of the injected water in the oil. If the mixing pressure drop is too low, the water injection cannot fully exert the washing effect. If the mixing pressure drop is too high, it may cause excessive emulsification, which not only consumes more energy, but also has low desalination and dehydration efficiency. The amount of demulsifier varies greatly depending on the crude oil. Generally 15 to 25 mg/L.

The injection amount of demulsifier is determined based on the specific gravity of crude oil, API value, water content and other factors. It has oil solubility and water solubility. The dosage is difficult to say. The mixing pressure difference is generally controlled at 0.03-0.08MPA.

The mixing valve adjusts the mixing intensity of crude oil and water. The greater the mixing intensity (that is, the greater the pressure difference), the more uniform the oil and water are mixed, the stronger the emulsification, and the more difficult it is to break the emulsification. On the contrary, if the oil and water are not mixed thoroughly, it is easy to dehydrate and it is difficult to desalinate.

The function of the electric desalting mixing valve is to fully mix the oil and demulsifier. The size of the pressure difference depends on the properties of the crude oil. Generally, the pressure drop of light oil is slightly larger than that of heavy oil between 30 and 80KPA.

The principle has been mentioned before and I won’t repeat it. The density of crude oil in our device is generally 0.90g/cm3, and the mixing pressure drop is 80-150KPa. Generally, the low point is the first level and the high point is the second level. Demulsifiers are divided into water solubility and oil solubility. The water solubility generally has a dosage of 30ppm, and the oil solubility is 8 to 10ppm. Demulsifiers are more specific to crude oil and need to be screened.

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The main function of the electric desalination device is desalination, dehydration and demetallization. Therefore, mixing before entering the desalination tank is necessary. It is usually a mixing valve + static mixer. The mixing intensity should neither be too large nor too small. If it is too large (that is, the pressure difference is large), emulsification The stronger the degree, the better the salt washing effect, but the difficulty of water separation increases, and an emulsified layer is easily formed, which also has a great impact on the quality of drainage water (mainly due to high oil content). On the contrary, if the oil and water are not mixed thoroughly, even if dehydration can be achieved, the purpose of desalination has not been achieved. Since there are certain fluctuations in the crude oil processing in the refinery, the adjustment of the pressure difference needs to comprehensively refer to the salt and water content of the crude oil after dehydration, and the problem of cutting water and oil must also be paid attention to! As for demulsifiers, they are mainly divided into oil-soluble and water-soluble. Generally speaking, the dosage of oil-soluble is smaller than that of water-soluble. However, the price of oil-soluble is generally higher, so the comprehensive consideration mainly depends on the effect. Currently, there are almost no broad-spectrum demulsifiers. Screening tests are required for crude oil processed by different refineries, and the laboratory will generally obtain a preliminary dosage.