Electrical Oil Dehydrator 2

[Petroleo]

Hello All,

Do you think it is possible to switch a conventional 1st stage separator with an electrical oil dehydrator? the dehydrator is 6 times bigger but I do not find technical information about its limitations. I mean what is the main characteristic of this type of vessel? The only info I have is the design pressure, the 1st stage separator can handle 3 times higher pressure. Possibly higher gas rates will have to be handled.

Thanks in advance,
Petroleo

 

[monaco8774]

What you call a first stage seperator is doing two functions, seperation of gas and seperation of water from oil it works by gravity alone, i.e. oil is lighter than water so over time they seperate. However for very small droplets or droplets of oil in water emulsions, gravity seperation will not get all of the water out.

What you call electrical oil dehydrator I call Electrostatic coalescers, they have grids in them that cause seperation of small droplets of water that cannot be seperated by gravity alone using electricity that forces teh water droplets together. since the water has a charge on it it is effected by electrical charge and the field can force the very small water droplets together so they coalesce become bigger and then drop out under gravity. They are not designed to take gas in them as there is always a potential for explosions when you have electricity and gas mixing together (of coarse you need some oxygen aswell.)

Since they are designed to knock out much smaller droplet sizes they have bigger retention times, around 20 minutes is typical whereas for a normal gravity seperator you are talking only 3 to 5 minutes.

If you want to use the dehydrator it can be done but you will need to modify the design to have a gas interface and gas outlet , possible install some internals and of coarse you cannot increase the operating pressure that it was originally designed for.

 

[Petroleo]

Thanks a lot monaco8774, that was exactly the type of information I was looking for!

 

[25362]

Being water a polar molecule its settling rate can be enhanced by electricity. Hydrocarbons are considered non-polar.

High voltage (20,000 V) is applied across sets of electric plates or grids. Water droplets attracted to these grids or plates coalesce into larger droplets which fall rapidly to the bottom of the vessel.

These electric coalescers (or precipitators) may increase the settling rate of water over that of gravity settlers by a factor of ~ 5, for an equal droplet size distribution.