Condensate line with direct pumping to the boiler

[spacebeer]

Hi guys!

I saw an installation as shown in the image below.

What do you think that are the advantages of having condensate pumps putting the condensate directly in the boiler and not in a degasifier. Not loosing energy in the degasifier, flash steam, cost of the degasifier..??

 

[EdStainless]

But what about controlling dissolved gasses?
Are there actually ZERO leaks in the condenser? Not any real one that I have ever seen unless it is above atmospheric pressure.
But then there are still issues of how well degassed the makeup water is, after all CO2 and such will ruin your boiler, and your day.

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P.E. Metallurgy

 

[spacebeer]

Dear EdStainless,

Thanks for the reply.
Not sure if i understood all of your points, but to clarify, do you support this solution or not?
When i mention "condensate", it has a condensate tank that flashes part of the condensate.

 

[LittleInch]

Well like it says, if you de gassify, you have dissolved gasses.

This isn't good for a number of reasons - e.g.

https://www.spiraxsarco.com/learn-a...ng-principles-and-heat-transfer/steam-quality

So sure, you save a bit of energy, but then your boiler furs up and corrodes faster.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[spacebeer]

So,

My conclusion is that you agree with me that this installation is not the ideal...wright?
If we install a new HRSG in parallel, do you agree also that this should be an ideal opportunity to justify the installation of a new degasifier? Also because the HRSG is water tube type, so if we will maintain this logic, it should have new codnensate pumps and the only place to introduce the condensate line in the new HRSG is the steam drum....not the ideal...do you agree?

 

[Compositepro]

Your drawing shows a control valve which can direct condensate to the degassifier. If only a fraction of the condensate passes through the degassifier that should be sufficient.

 

[EdStainless]

So what is currently installed between the condenser hotwell and the inlet on your drawing?
What is the condensate quality?
I have never seen a plant that hit the required O2 and conductivity values without degassing a significant fraction of the condensate.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy

 

[Compositepro]

It appears to me that the flashing condensate is what powers the deaerator. Flashing all of your 15 bar condensate at zero bar before pumping back into the boiler would be very wasteful.

 

[Dhurjati Sen]

Dear spacebeer,

This design (without deaerator) could be ok if and only if you can dose adequate sodium sulphite / hydrazine (oxygen scavenger) and morpholene (CO₂ remover) to the condensate before it enters the boiler in order to prevent corrosion.

Of course, this could lead to more often blowdowns and increased cost of chemicals.

Try posting in the Chemical Plant Design & Operations forum where experts like georgevaghese could assist you more. You require more inputs from the process side.

Regards.

DHURJATI SEN
Kolkata, India