Is it more efficient to preheat your feed water? 1

[YungPlantEng]

If for whatever reason we aren’t having corrosion issues with our feed water at 140F, does it actually save money to use steam produced from that boiler to heat the feed water tank to 180F? Or is it all a wash in the end since we’re talking a 40 degree difference that would’ve been made up in the boiler without excess steam usage

 

[pierreick]

Hi,
You may want to see this PPT presentation . It may give you ideas about energy recovery
Good luck
Pierre

 

[EdStainless]

In most cases yes it will save energy.
It also lessens the thermal stress on the boiler.
But you really need to run the exact numbers (temps and flows) for your situation to see if the project is worth doing.

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P.E. Metallurgy, consulting work welcomed

 

[TBP]

What kind of corrosion are you experiencing? If it's pitting, then that is likely from dissolved oxygen in the feedwater and with feedwater at 140*F, you obviously don't have a deaerator. Note that simply heating the feedwater more will not solve a dissolved oxygen problem, you must vent it.

 

[YungPlantEng]

We aren’t having corrosion issues. I’m simply asking if preheating the feedwater via excess steam has value. Presumably we would consume the same amount of natural gas if we didn’t preheat

 

[3DDave]

Where does the extra steam go now?

 

[TBP]

Should have read your post more carefully - sorry.

 

[MJCronin]

YungLove ...

In order to properly and accurately answer your question, you must tell us more details about your particular system

You have given us essentially nothing aside from your usage of the word "boiler"

- Small or Big ? .... Size and type of your boiler, fuel, flue gas path, steam generation rate, stable or changing steam demand
- Feedwater into boiler ?.... Describe your system, temperatures, pressures and qualities
- Minimum feedwater temperature ?.... Does your boiler have one ?.... Or is this an ancient 50 year old unit with no records

More information

MJCronin
Sr. Process Engineer

 

[crshears]

Conventional "boiler" or once-through steam generator?

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[1503-44]

Such an easy question to ask. So difficult to answer (even with great info).

A black swan to a turkey is a white swan to the butcher ... and to Boeing.