×
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

GTG-HRSG Startup

GTG-HRSG Startup

GTG-HRSG Startup

(OP)
Hi,

In 4 to 6 months time we are planning to commission 4 GTGs (F5 size) and 4 HRSGs (95 t/h with supplementary firing). Our gas turbine is closed coupled with the HRSG without the bypass stack i.e. if GTG down, HRSG will also down, vice versa.

I was informed that due to not having a bypass stack, it will take longer time for the GTG to reach its full rated capacity. For cold standby it will take 7 hours. For hot standby it will take 3 hours. The reason is to reduce the thermal shock on the HRSG tube. Is that really the case? I just feel this is too long and my understanding is that GTG is always a fast response machine.

Thanks

norzul

RE: GTG-HRSG Startup

We have 3 Frame 6 GT's in the same configuration as you.  For a cold start-up, we bring the GT up to full-speed/no-load and sit there for 30-45 minutes.  Then we synch the generator and raise the load about 5 MW every 5-10 minutes.  I don't see why your start-up time would be as long as you've stated.  Contact the HRSG manufacturer regarding this since its the HRSG that is the limiting factor.

RE: GTG-HRSG Startup

You asked a question in another thread about a bypass stack.  The value of this is that your GTG can be brought up to full load with the exhaust flow diverted to the bypass stack.  Then the exhaust can be diverted little by little to the HRSG until it is up to temperature.

If you have the capital to spend and the need for power to justify it, you ought to do it.  There are companies who build diverter dampers specifically for this service, and I have seen them used on Frame 5's quite a lot.

Try www.effox.com for a starter.  I think you will find some examples of what you are looking for on their site.

rmw

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