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

Thermal Outbreathing Calculation - Api 2000 6Th Edition


This topic has been archived. This means that you cannot reply to this topic.
3 replies to this topic
Share this topic:
| More

#1 JasonGan90

JasonGan90

    Brand New Member

  • Members
  • 8 posts

Posted 29 August 2016 - 02:37 AM

Dear all, i'm having a question with regards to API 2000 6th edition section 4.3.2.3.2 calculations for thermal outbreathing.

 

I have a sour water tank which is idle most of the time, and the vent gas flow rate due to thermal outbreathing effects was calculated using formula 5, whereby

 

V (in Nm3/h) = (latitude factor)*(volume of vapour in tank^0.9)*(insulation factor)

 

This tank does not have a PVV but it does have a pressure control valve. Now the actual thermal outbreathing flow rate determined from the valve operating curve is only about 20% of the calculated thermal outbreathing flow rate using the equation above, and i've got 2 years of operating experience for this tank.

 

Could somebody please share or explain to me the vast difference in values between calculated and actual? This tank is blanketed using N2 and i've converted the calculated V (in Nm3/h) from air to N2 for comparison with the PCV operating curve.



#2 breizh

breizh

    Gold Member

  • Admin
  • 6,282 posts

Posted 29 August 2016 - 03:32 AM

Hi ,

Refer to the excel sheet attached , You should consider the total volume of the tank if I'm not mistaken .

 

note : N2 or Air is quite the same and will not affect much your calculation .

 

hope this helps

 

Breizh


Edited by breizh, 29 August 2016 - 03:37 AM.


#3 JasonGan90

JasonGan90

    Brand New Member

  • Members
  • 8 posts

Posted 29 August 2016 - 04:12 AM

Hi breizh,

 

Thanks for the reply. Yes indeed my calculations were performed for total volume of the tank, using the formula in the excel spreadsheet. 

 

What I do not understand is the big difference between calculated thermal outbreathing value and actual thermal outbreathing value



#4 JasonGan90

JasonGan90

    Brand New Member

  • Members
  • 8 posts

Posted 06 September 2016 - 01:03 AM

Hello~ Is there anyone that could help me understand?

 

Thanks!






Similar Topics