×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Water Saturation

Water Saturation

Water Saturation

(OP)
All:

Could you help me in determining the amount of water(steam) required for saturating the hot air stream ? This is 100 scfm of  air at 265F and 1psig.

Thanks,
sp77

RE: Water Saturation

265F is above the boiling point for water at 1PSIG.  This makes it superheated steam.  Even if there was no air present you would not get any moisture precipitating. So you would never be able to saturate air with steam under these conditions - the steam itself is not saturated.

RE: Water Saturation


Saturation could be attained by quenching the hot air stream down to a temperature at which the vapor pressure of water is below the prevailing total pressure of 1 psig.

RE: Water Saturation

(OP)
All:

Thanks for your comments. But I am looking for some sort of steam injection source where the air stream would be say 70-80% saturated and not fully saturated. Could I be able to determine the quantity of steam to be injected.

Regards,

sp77.

RE: Water Saturation

sp77,

Because full saturation makes no sense in these conditions, 70-80% saturation makes no sense either.

What is the temperature and pressure of the air before you add in the steam?

What pressure and temperature steam do you have available?

What pressure and temperature do you want the air to be after the steam in injected?

Why do you want to do this?  If you explain your application we may be able to see what you are trying to achieve.

RE: Water Saturation

You are probably speaking of moisture content not saturation. Answering katmar's questions, may help you in getting the help you are seeking.

RE: Water Saturation

(OP)
Katmar:

The availabe steam source is 1000psig (70%)steam. Right now the air stream is at 50scfm ,1psig, 265 F (with no steam addition).  This hot air stream has H2S ppms which will pass thru sulfur removal beds and the stream needs to be water saturated for the efficient bed use. So trying to figure out amount of water to be added for saturation??

Regards,

sp77.

RE: Water Saturation

sp77, at what temperature are the H2S-removing beds working ? 40oC or so ?

RE: Water Saturation

(OP)
Yes you can say around 40C (100F)

Thanks,

sp77

RE: Water Saturation

In the face of an inept query and absurd data, I've got to interject some comments/questions--

If sp77 is really trying to saturate a heated (265 oF) air stream and assuming this is not an academic exercise or homework problem, why doesn't he do it the way we all would do it in an industrial application: simply sparge the hot air in a pool of cool, clear water?  Or better still, spray the cool, clear water into a packed bed, counter-current to the rising hot air?  It's called a humidifier.

Spraying hot, high pressure steam into the air is only going to heat even more.  Is this a Hot Zinc Oxide Unit Operation?

RE: Water Saturation


sp77.


This means that the air stream must be pre-cooled, besides being moistened.

For moist air at 100oF the tabulated vapor pressure of water is 0.949 psia. If the total pressure is, say, 15.5 psia, full saturation would be attained with 6.1% water by volume. This is considering air and its humidity an ideal gas when mol%, i.e, volume%, equals partial pressure.

Have you already considered the procedure to be used to cool and humidify your hot air stream ?

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources