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

0

Psv Downstream Hot Oil Heater


4 replies to this topic
Share this topic:
| More

#1 Shahine

Shahine

    Junior Member

  • Members
  • 21 posts

Posted 24 June 2018 - 04:23 AM

Dears:

 

In our plant the hot oil system contains hot oil  heater which is fitted with inlet and outlet shutdown valves (Shutdown valves were not exist in the original design by heater supplier but the adding of these valves due to HAZOP recommendation and the cause to add such recommendation is tube leak in burner box which may be lead to out of control fire)

 

Accordingly HAZOP team recommend to add ESD valves at the inlet and outlet of the heater!

 

Hope to know, to add ESD valves at heater inlet/outlet to avoid out of control fire due to tube leak in burner box is valid recommendation or not, Specially heater BMS provide TAHH at the heater stack to trip the heater by close shutdown valves on fuel gas supply?

 

Also, there is a PSV between the heater and the outlet shutdown valve. The design case for this PSV is Abnormal heat input (PSV has relieving temperature of 400 oC and the flaring flow rate equal to inlet flow rate to the heater) 

 

The problem is that this PSV is connected to LP flare header (design temp. 200 oC) , and such connection will cause a potential over temperature leading to abnormal stresses and loss of containment due to venting from hot source.

 

Hope to know:

 

Does the connection of mentioned PSV to flare header right?

Is it right to consider relieving load due to abnormal heat input to be equal the total flow rate to the heater or not?

 

Also, consider that the design pressure of the hot oil system is 10 barg  (the system is 300# rating due to design temperature 350 oC)

 

 

Attached Files



#2 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 24 June 2018 - 08:38 AM

Sounds like trouble to me.

 

Bobby



#3 Shahine

Shahine

    Junior Member

  • Members
  • 21 posts

Posted 25 June 2018 - 05:22 AM

Sounds like trouble to me.

 

Bobby

that mean you agree to remove the ESD valves upstream and downstream the heater



#4 Bobby Strain

Bobby Strain

    Gold Member

  • Members
  • 3,529 posts

Posted 25 June 2018 - 09:07 AM

I didn't offer any solution to you. You and your team need to go back to the drawing board.

 

Bobby



#5 SawsanAli311

SawsanAli311

    Gold Member

  • Members
  • 99 posts

Posted 07 September 2018 - 03:14 AM

Hi, 

 

We have a similar design in our plant and we have no ESDV directly at heater outlet but  at the individual end users i.e. ESDVs at the reboilers inlet hot oil lines. There is an inlet ESDV which closes only on total plant shutdown.

A thermal expansion relief valve is designed for heater's blocked in condition with continuous heat input without giving credit for the favorable IPF response of BMS. The size is estimated based on API 521 liquid expansion equation. 

The PRV discharges to a dedicated hot oil sump drum as its relief is mainly liquid due to the very high boiling point of the chemical selected as hot oil.  Discharging this liquid to flare would be really problematic in my opinion.






Similar Topics