2 replies to this topic

[Yasser M. Abd Al-Rahman]

Dear all,

 

Regarding the PSV sizing of shell and tube heat exchanger. Hot oil in tube for heating water in shell side to steam. If I can apply relief sizing for single phase, which case I should choose; liquid or Vapor case?

 

Thanks a lot

[shahidulislam48]

Hi,

 

It depends on which side you are willing to put your PSV.

 

You had better try these links to have a preliminary idea.

 

http://www.cheresour...heat-exchanger/

http://www.cheresour...-for-fire-case/

http://www.cheresour...-for-exchanger/

http://www.cheresour...f-an-exchanger/

Edited by shahidulislam48, 08 February 2017 - 11:39 PM.

[paulhorth]

Yasser.

 

if I understand you correctly, you have a steam boiler heated by hot oil.  The steam side has to be protected by a relief valve. The relieved fluid is steam. (just like on an old fashioned railway loco). There are several relief cases. The blocked outlet case relief rate is the maximum steam generation rate at the relief pressure and with normal hot oil flowrate.  You should also check the case with maximum hot oil flow (hot oil control valve failure case). In this case you can take credit for the normal process steam flow continuing, the extra steam has to be relieved.  Another case would be tube rupture, if the hot oil pressure is higher than the steam side pressure, hot oil flowing directly into the water will generate a lot of steam.

The hot oil side will need a relief valve if its design pressure is lower than the steam side design pressure.

 

Paul