×
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

Glassline Reactor Cooled by Flashing and then make up water hazards?

Glassline Reactor Cooled by Flashing and then make up water hazards?

Glassline Reactor Cooled by Flashing and then make up water hazards?

(OP)
I am working on a Plant Expansion.  We are making a product in a glass lined reactor.  The product is inorganic.  The temperature is about 280 at the end of the reaction.  It is mostly an inorganic salt and water (about 50% water.)

To save capital it has been proposed
1.  to evaporate enough water to bring the product down to its boiling point (about 235 F)  

2. Then to bring it down to transfer temperature (about 10 F to 170 F) add make up water.

I don't think that this would pass permit review, but I am making my point around two points.

1. We need to vent off about 2600 gallons of water.  That is about 545,000 cuft of steam.  This steam will entrain some some product.  We cannot have opacity greater than 20% for more than 6 minutes in this state for combined water.
         a. If the vent down exceeds the sounders brown
             velocity we will have entrainment (not total
             flooding, but entrainment.)
         b. The to keep the streams unentrained
            (uncombined)we must below that venting          
             veloicty?  Is this correct?
The equation I am using is:
            Vsb=K*(RHOl/(RHOl-RHOv)^0.5

2. I also believe there is a hazard of charging cold water to the vessel at 230 F to bring it down to temperature.
        a.  The 2,600 gallons give about 350 cuft of vapor
            space.  The first ~1.5 gallons of water will
            flash to fill the vapor space and we need to add
            about 1,600 gallons to bring the reactor down
            to 210 F.  Then we can add the remaining 1,000
            gallons.
        b.  If the reactor is blocked in I believe we will
            experience steam hammer.  this could damage
            the vessels glass, shaft, agitator seal.
        c. left vented to atm (through the scrubber) we
            will be back with the previous problem of
            sounders brown velocity limitations.

Where can I find an equation for the force created from flashing water in a closed vessel or pipe?  

Do you concur with my analysis?  Can anyone point me to supporting documentation for the hazards of flashing water?

I think we need to go with the original proposed cooling tower and tempered water exchangers to cool the vessel.

 

RE: Glassline Reactor Cooled by Flashing and then make up water hazards?

(OP)
Sorry,  The equaiton of velocity limits is Vsb or K = VV *(RHOg/(RHOL-RHOg)^0.5

The VV must stay below Vsb.

I am however seeing carry over lower than the K of 0.32 ft/sec mentioned in the litature.

Is there a different one from boiling or venting a superheated vessel?

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