Jump to content



Featured Articles

Check out the latest featured articles.

File Library

Check out the latest downloads available in the File Library.

New Article

Product Viscosity vs. Shear

Featured File

Vertical Tank Selection

New Blog Entry

Low Flow in Pipes- posted in Ankur's blog

4

Relief Load Calculation


5 replies to this topic
Share this topic:
| More

#1 Devandra Godara

Devandra Godara

    Brand New Member

  • Members
  • 8 posts

Posted 25 August 2022 - 11:59 PM

Hello everyone,

 

I am calculating relief load for one of the unit in refinery. Here We have a system where a control valve is connected to ESD. The ESD gets triggered during the failure scenario, which closes down the control valve. Now for calculating unmitigated load, the control valve was assumed to be in manual and ESD considered to fail (Hence open valve), But to calculate mitigated load (ESD to work), If considered valve to be in manual. Will the ESD able to close down a control valve taken in Manual.

 

Thanks 

Devandra Godara



#2 Chemitofreak

Chemitofreak

    Gold Member

  • Members
  • 286 posts

Posted 26 August 2022 - 02:39 AM

As per my understanding the control elements linked with ESD should not be put on manual unless really-really and to be done under operator observation i.e. start-up/shutdown. If in manual, it will not close even if the ESD is supposed to close it.



#3 latexman

latexman

    Gold Member

  • Admin
  • 1,428 posts

Posted 26 August 2022 - 06:06 AM

DCS logic will NOT close a normally installed CV in manual.



#4 Pilesar

Pilesar

    Gold Member

  • Members
  • 1,045 posts

Posted 26 August 2022 - 06:24 AM

ESD can be configured to close a CV in manual if it is completely independent of DCS. An example is the ESD control has its own solenoid on the valve air supply to reliably dump the air to the valve and close the valve when ESD is triggered. With no air to the valve, the DCS control mode would not matter. Instrument connection details should be configured by expert.



#5 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,301 posts

Posted 26 August 2022 - 05:09 PM

If it is critical, there should be a separate valve. If not, and it should be closed from ESD, there must be no handwheel on the valve.

 

Bobby



#6 Bitan729

Bitan729

    Junior Member

  • Members
  • 27 posts

Posted 03 September 2022 - 03:27 PM

If it is fail to close valve then a solenoid can be installed in instrument air line going to the valve actuator. If ESD is pressed then the solenoid will get de-energized and closed the valve, regardless the valve is kept in auto or manual.   






Similar Topics