×
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

Boiler Restart Procedure after Cleaning

Boiler Restart Procedure after Cleaning

Boiler Restart Procedure after Cleaning

(OP)
I have heard conflicting arguments about the restart of a boiler after being chemically cleaned (or after lay-up). One method employs the rechraging of the boiler with normal boiler feed water (140ºF) while the other uses "ambient" water. It seems logical to me that boiler feedwater should be used versus city water, but the latter argument stresses that the temperature of the boiler feed water might "shock" the tubes????? I could use some insight here please!

RE: Boiler Restart Procedure after Cleaning

The correct water to use is your treated boiler feed water.  The 140 degree tempereature, probably from your hotwell, should present no thermal shock to boiler tubes. Afterall, 140 degrees is probably about the limit for sustained human contact, but certainly no problem for steel tubes.

RE: Boiler Restart Procedure after Cleaning

You are correct. The boiler should be drained and filled with treated boiler water as defined in the O&M.
The temperature criteria is typically something like a maximum difference of 60°C-80°C/140°F-175°F (mainly depending on the drum thickness) between water and metal temperature (assumed to be ambiant temperature after layup for a few weeks).

RE: Boiler Restart Procedure after Cleaning

By all ,means do NOT use city water. The start-up of a boiler after a chem clean should be with treated feedwater otherwise you will undo that which was accomplished with a chem clean.

Typically for thermal shock as long as the delta T between the metal and feedwater temperature is less than 150 deg F you should be ok. My main concern would be to assure that untreated feedwater does not enter your tube circuit.

RE: Boiler Restart Procedure after Cleaning

(OP)
Thanks for all the info. I have been corrected about the temperature of the treated feed water. The temperature is that of deaereated boiler feedwater - 228º. Is this a problem for the tubes? I understand the treated vs. untreated part of my previous question.

Thanks again.

RE: Boiler Restart Procedure after Cleaning

At that temperature the water will flash to steam in as much as the boiler is empty and under zero (gague) pressure.  You don't want that.  The water should be cooled down so there is less differential, see the post from Metengr for that.

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