Desalter
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A desalter is a process unit in an
The term desalter may also refer to a
Desalting crude oil
The salts that are most frequently present in crude oil are calcium, sodium and magnesium chlorides. If these compounds are not removed from the oil several problems arise in the refining process. The high temperatures that occur downstream in the process could cause water hydrolysis, which in turn allows the formation of corrosive hydrochloric acid. Sand, silts and salt cause deposits and foul heat exchangers or result in plugging. The need to supply heat to vaporize water reduces crude pre-heat capacity. Sodium, arsenic and other metals can poison catalysts. By removing the suspended solids, they are not carried into the burner and eventually flue gas, where they would cause problems with environmental compliance such as flue gas opacity norms.
Crude oil to be desalted is heated to a temperature of 100-150 °C and mixed with 4-10% fresh water, which dilutes the salt. The mixture is then pumped into a settling tank where the salt water separates from the oil and is drawn off. An electrostatic field is applied by electrodes in the settling tank, inducing polarization of the water droplets floating in the larger volume of oil. This results in the water droplets clumping together and settling to the bottom of the tank.[2]
See also
- Brackish water
- Water desalination
References
- ^ "Measurement of salt content in petroleum flow lines - Patent 4352288". Retrieved 2009-03-11.
- ^ https://m.tau.ac.il/~tsirel/dump/Static/knowino.org/wiki/Crude_oil_desalter.html Crude oil desalter
External links
- Desalting in refinery
- Desalting theory Archived 2006-09-09 at the Wayback Machine
- Desalter animation