4 replies to this topic

[Novak]

Can anyone advise whether it is worth to install desalter for crude with salt content ~10-20 PTB. Or it is better just to inject anticorrosion agents?

Additionally, any experience with desalting of heavy crudes (10-15 API, e.g. Venezela crudes)? Can standard electrostatic desalter handle such heavy crude (with respect to high viscosity and low difference between crude/water density thus poor separation/efficiency)?

Many thanks! 

[ankur2061]

paruzekk,

 

You have not specified whether this is a refinery desalter or whether the outlet oil from the desalter is sold to a purchaser. If it is the latter case, then it depends on the agreed salt content in the oil purchase agreement. Many purchasers prefer a salt content of maximum 10 PTB in the purchased oil.

 

If for a Crude distillation unit you are assured of crude oil supply of 10 PTB or less which is very unlikely due to changing crude supplies and characteristics then there is a possibility of excluding a desalter. However, I would not advise it in a refinery operation, since having a desalter gives you the right amount of flexibility in processing different types of crude. In fact, in refinery operations, a 2-stage desalting is an established practice to allow wide flexibility in processing different types of crude.

 

Desalters can be custom designed to operate with very heavy naphthenic crude including Venezuelan crude. Desalter manufacturers ask for crude assay in the specification sheet for desalter for this very reason, so that they can customize the internals and metallurgy to suit the crude assay. 

 

Hope this helps.

 

Regards,

Ankur.

[gegio1960]

The desalter(s) shall be installed.

Refineries in Venezuela, processing their heavy crudes, are designed and operated with desalters, also the most recent ones.

Alternative technologies, proposed in the last 20 years, have not been adopted.

The second stage of desalting is only needed when VGOs and BOBs have to be further processed in catalytic units (salt content in these cuts shall be reduced to less than 1 PTB).

Desalter business is, more or less, a monopolistic business of Cameron.

Good luck!

[Novak]

To Ankur2061 - It is for refinery purposes, namely for bitumen production CDU/VDU plant where no other downstream units will be installed as the main product is bitumen and the rest is sold out as straight byproducts. As per assays of crudes that will be processed the max salt should be 30 PTB but I agree with you that this cannot be 100% assured. I am just curious if this 30 ptb can cause real problems (corrosion, deposits) in CDU/VDU from the long term point of view or for this application (bitumen focused CDU/VDU) it is possible just to inject some anticorrosion agents.

 

To gegio1960 - as I mentioned in the reply to Ankur2061, the main product is bitumen, all other byproducts are considered as "wastes". So it seems that one stage desalter should be sufficient.

 

Thank you

[Arsal]

You can search "desalting requirement" in this forum.and there is a good discussion on your concern.