What are the methods for dehydrating crude oil in crude oil tanks?
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What other dehydration methods and process flows exist for dehydrating crude oil in crude oil tanks, in addition to physical sedimentation at the tank bottom via manual valve operation for dehydration and secondary dehydration, as well as dehydration after crude oil pretreatment?
The desalination and dewatering of crude oil is also known as pretreatment. Crude oil transported from oil fields to refineries often contains salts (mainly chlorides) and water (either dissolved in the oil or in an emulsified state), which can cause equipment corrosion, lead to scaling on the inner walls of the equipment, and affect the composition of the refined oil; therefore, it needs to be removed before processing. The common method is to add demulsifiers and water, which causes the water in the oil to aggregate and separate from it; the salts dissolve in the water. A high-voltage electric field is then used to help remove the larger water droplets that are formed.
Pre-dehydration within the storage tank is achieved by combining heated sedimentation with an automatic water cut-off device, while deep desalination and dehydration are carried out through electrodesalination.
An automatic water cut-off device can reduce the oil content in the wastewater discharged, thereby minimizing pollution and also reducing the workload for operators.
I agree with the view from the third floor; additionally, a cyclone can be installed to recover oil from water or to remove water from crude oil before it enters the tank