Steam byproduct condensation 1

[MNALE276]

Dear All,

How much chiller tonnage would be required to condense 135C steam at atmospheric pressure to water at 80C? 900 kgs of water is collected per hour.

Thanks

MK

 

[Latexman]

Sounds like homework to me. Homework is not allowed. Are you a student?

Good Luck,
Latexman

 

[MNALE276]

No sir, not homework, but I wish I was still doing homework! This is an actual design question for a line expansion at one of our manufacturing sites. We are entering phase II design and this detail was overlooked in the first phase. I may need to budget for an additional chiller to the 200 ton unit on-site.

Thanks,
MK

 

[Compositepro]

Chiller? what about a cooling tower? Do you know how to read a steam table to answer your own question?

 

[EdStainless]

Break the problem in two parts.
Go to your steam/water tables and look up the amount of heat that you will need to remove to cool/condense/sub-cool the water.
Then look for a cooling medium.
Do you have any sub-80C cooling water on site? If so then you are left just sizing a heat exchanger.
If you need to provide the cooling then why not look at a small cooling tower to do the job.
I don't see any need for a chiller unless you are going below ambient temp.

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P.E. Metallurgy

 

[Latexman]

Are you a degreed Engineer? This will help us help you.

Good Luck,
Latexman

 

[Latexman]

Steam Tables
@ 133.5^oC Hsteam = 2724.7 kJ/kg
@ 135.8^oC Hsteam = 2727.6 kJ/kg
Therefore @ 135^oC Hsteam = 2726.6 kJ/kg

@ 78.7^oC Hwater = 329.6 kJ/kg
@ 81.3^oC Hwater = 340.6 kJ/kg
Therefore @ 80^oC Hwater = 335.1 kJ/kg

900 kg/hr x (2726.6 - 335.1 kJ/kg) = 2152350 kJ/hr = 2040034 Btu/hr = 170 tons of refrigeration

But as others have said, you don't need chilled water to condense 135^oC steam to 80^oC water. Cooling tower water (~ 35^oC) is fine.

Good Luck,
Latexman

 

[MNALE276]

Yes, but many years removed from an engineering role. I apologize I realize I left a critical piece of information out of the problem statement. The steam byproduct has a contaminant that cannot be discharged to the atmosphere. The wastewater is collected and sent for treatment off-site. Thus the reason for not pursuing a tower. 170 tons was the estimate I initially had but thouoght this seemed awfully high.

I appreciate the help Latexman and all!

Regards
MK

 

[EdStainless]

Keep your process side in s closed system, but cool it with water that is looped through a cooling tower.
Or use a closed fan cooled unit for cooling, either like a fin-fan cooler or one from Graham Manufacturing (closed but with fans and water on the outside).

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

 

[quark]

135C steam at atmospheric pressure? Need some details. It may, already, be condensate with flash steam. In any case, cooling towers are cheaper option by CapEx and OpEx