A question regarding electrodialysis
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In atmospheric and vacuum distillation units, flow is generally from top to bottom; in some units, it is from bottom to top as well. Given that the specific gravity of the crude oil used nowadays is quite high, close to that of water, I would like to ask how to ensure good separation efficiency and a high desalination rate
Oils with a higher specific gravity can be blended with lighter oils; the mixing ratio needs to be calculated carefully: lol
Good desalination performance relies on effective dehydration. The principle of electrodesalination is based on the Stocks formula: U = D²△rg/18μ, where D is the diameter of the droplets, typically ranging from 1 to 10μm; the total surface area of all droplets is around 12,000 m²/m³. △r represents the density difference between water and crude oil, while μ denotes the viscosity of the crude oil. Firstly, increasing the temperature can reduce viscosity, which is beneficial； Raising the temperature reduces △r, which is unfavorable ； Therefore, the operating temperature needs to be carefully determined, and a suitable demulsifier must also be chosen. A good demulsifier can increase D, which is beneficial for desalination and dehydration. As for the water injection volume, it is generally 4–6% (V) of the crude oil feed rate, and this amount should be adjusted based on the salt content of the crude oil after desalination.
What can truly be controlled are temperature, pressure, and the amount of water injected; other conditions cannot be changed. . . .
Temperature, water injection volume, demulsifier type and dosage, mixing intensity, water injection temperature, oil-water interface level, and the currently popular issue of lightening heavy oils. . . . . Adjustments and controls are made by taking various factors into account. High-speed electrodesalination is generally used for the case where fluid enters from above and exits from below, while low-speed electrodesalination is used for the case where fluid enters from below and exits from above. Both methods have many applications, with the former being more suitable for thin oils.
What the poster is referring to is the electrodesalination technology for heavy oil, which is the most challenging in electrodesalination processes. . . There aren’t many good solutions for dealing with this type of oil; the most important aspects are process evaluation, selecting the appropriate demulsifier, suitable temperature and water levels, as well as the mixing intensity. Generally, high temperature (around 145), high pressure (6–9 kg of pressure), and 5–15% water injection. The dosage of the demulsifier is 20–1500 PPm. . . :handshake
1. Select a demulsifier 2. Mix the raw materials for processing 3. Add several more stages of electrodeposition
It mainly involves controlling the water injection volume and the demulsification dosage, as well as monitoring the mixing effect of electrodesalination! If the pressure drop in the static mixer is high, then the mixing effect will be better, and the electrodeposition effect will also be improved. Additionally, increasing the residence time of the oil in the electrodeposition tank might have a certain positive effect!