HRSG/Condensate Filtration/Polishing Advice

[CW3]

Here's the situation (theoretical at this point):

I need to build a filtering/polishing system that can take hot condensate at approximately 180-200F and remove as much of the suspended solids as I can. It should be able to handle flow rates up to 1000 gpm. The conductivity of this condensate will be higher than would be experienced in a normal condenser/hotwell to LP system of a combined cycle plant. I can pump off the initial condensate to a raw water tank, to go to the normal water treatment cycle, but as the condensate get "cleaner", I wnat to be able to send it either to the condensate storage tank, or back to the LP system in the HRSG.

That's the desired output.....what I need to know is, what type of media (type, size, etc.) I should be considering for doing this, noting that the temperature is higher than what is acceptable by some of the 3rd-party filer/polisher rental companies.......

I know I'm looking at multiple filters, so that I can backwash one while running the others.

ANy thoughts, comments, "You're crazy!!"s.......?

Thanks in advance.

CW3

 

[GarySCWSVI]

Media Type: There are 2 good ways to go using ion exchange resins for Condensate Polishing and Purification.

A deep bed ion exchange unit acts as an efficient filter and depending on the inlet concentration of debris, 70 - 90% removal of debris is obtained. Particle size of the debris will dictate the degree of removal achieved. The debris can be satisfactorily removed from the bed by air scouring and backwashing.

Use of Powdered Ion Exchange Resins Pre-coat filters have been adapted for use with powdered lon Exchange resin. A thin film of powdered cation and anion resinsis formed onto the outside of a hollow cylindrical element. A variety of designs of elements exist but usually they comprise of
filters wound onto a perforated stainless steel former. The liquid to be treated flows inwards passing through the ion exchange resin material and out to service.

There are sources for both of these media. In some cases both types of media beds are used in any one application. The primary advantage is in not only filtering debris but in doing ion exchange removal of dissolved metal ions that have contaminated the condensate. You can contact me privately if you care to in order to learn who the suppliers are in your geographical area. You can also technical information at the following web site:

http://www.puroliteusa.com

Do a "PRODUCT" search on that site for "Microlite" and then look at the link on the Microlite page to "Condensate Polishing". You can contact me privately at GSchreiber@puroliteusa.com

Gary Schreiber, CWS VI
The Purolite Co.

 

[bimr]

If all you want to do if filter this stream to remove the SS, you can go with a cartridge filter. There are plenty of installations using cartridge filters for condensate applications.

If you want to remove improve the conductivity, then you are going to have to cool this stream to around 120F. I have yet to run across an anion resin that can handle a higher temperature and remove silica.

 

[cub3bead]

The precoat type filter option has been mentioned but it can be operated only with with cellulosic media type precoat at your condensate temperatures. The other option is a strong acid cation resin bed regenerated with morpholine or ammonia. You have to regnerate with HCl first to get rid of the iron and then with the ammonia or morpholine. this type of unit will take temperatures up to 250F.

If you have a silica problem you will have to cool to 120F or less to get a strong base anion resin to survive.