When to use a deaerator versus heated feed tank versus a feed tank with no heat

[BronYrAur]

Hi all,

I am looking for something that I can cite as a "governing authority" or at least "industry standard" on when to use a deaerator versus a feed tank with a steam bundle or sparger, versus no heat in the feed tank. I understand the need and benefit of heat to remove oxygen, so please don't take this thread down that road. I also understand that the amount of fresh makeup water is a large contributing factor to the amount of oxygen need to be removed. I'm not looking for an explanation of the chemistry, but rather a good reference.

Is there a code or some other official reference that can be used to argue the point one way or the other? I'm trying to make the case to a client, but stating that "... In my experience..." isn't a strong argument.

I'm looking something to cite on when I absolutely should deaerate versus heated tank versus no heat in the tank. I know it's not a simple 1-2-3 scenario, but again I can't find anything that I would consider good guideline on this.

Thanks,

Steve

 

[lilliput1]

If your boiler need to run 24 hours year round you should have both. Use the unheated one when the deaerator need to be shut down for periodic inspection (required per code).
Good practice to preserve the life of the boiler and save energy would be to use dearator.

 

[MJCronin]

I believe that this is a matter of economics ...... How long does the client want the boiler to last ??

I believe that there are some US military standards regarding boiler room accessories. .....

A Deaerator is always required to extend boiler life.

MJCronin
Sr. Process Engineer

 

[davefitz]

For very small boilers , the initial cost of the boiler feed pump BFP becomes a competitive issue, so the use of the hot water tank ( Td < 248 F) allows use of a lower cost BFP, although the life cycle cost of the required extra chemicals will show the present value of the hot water tank system is inferior to the system that uses the DA with fewer chemicals .

"In this bright future, you can't forget your past..." Bob Marley

 

[DBreyer]

EN 12952 gives limits for dissolved O2 levels in boilers, depending on their pressure.
As the reachable O2 levels will be different, depending on the type of deaerator or tank you choose to use this could be a guide.
Further you could calculate the amount and cost of oxygen scavenger you need to reach the target level with the cheaper designs and show such that the life cycle costs for the lower CAPEX alternatives are higher than for a proper deaerator.

Daniel Breyer
Inspection Engineer

http://lnkd.in/dFcQA-w