Using an existing dielectric oil storage tank to store filtered water

[oddmanout]

I have a client who is proposing to use an existing approximately 100,000 gallon dielectric oil storage tank for storing filtered water. The stored filtered water will then be processed through a demineralizer system (strong acid cation followed by strong base anion followed by a mixed bed IX system). The demineralized water will be used for feed/makeup water to a supercritical steam generator. I have several reservations about their proposal and would like your objective, unbiased input.

1. Has anyone here ever attempted anything like this? If so, what advice would you give me? OR ... would you advise against this?

2. The tank is (I'm guessing) nearly 40 years old. I don't know if the interior of the tank is coated (although I would think it is). Is it possible to clean the interior of this tank well enough and apply an inert interior coating that would prevent contamination of the filtered water by traces of the dielectric oil? Since this water will be processed through an IX system and used as feed/makeup water for a supercritical steam generator organic contaminants are a very serious issue.

 

[Chance17]

In principle there is nothing wrong with using a 40-year old tank to store RAW water.
Any "leached" oil will foul or deactivate the demineralizer

 

[unclesyd]

Just make sure the tank didn't hold PCBs' at one time.

The tank is going to hard to clean and will probably have to be blasted prior to any attempt at coating.

I don't recall any coated CS tank being used for demineralized water without problems.

 

[MJCronin]

Suggest that you also post on the Storage Tank Forum, but ask about tank integrity

As I understand your post, you are really asking a few questions:

1 Tank integrity requirements
2 Purity requirements
3 Regulatory restrictions/requirements on tank re-use

I also suggest that you open the tank, get samples of any interior coatings and have them analyzed.

Is it really necessary to store this much filtered raw water ? What will be your demin water generation & usage rate ?

In my experience, most raw water storage tanks of this nature are much smaller.

-MJC

 

[bimr]

You would have to clean the tank and most likely reline the tank before you can use it for storage of demineralized water.

Most likely if the tank was sandblasted, the oil traces will be removed.

Most plants are now using a combination of RO/DI treatment rather than only DI treatment for preparation of ultrpure water. RO/DI is more economical to operate.

Power plants are generally more focused on removal of inorganics than removal of organics.