10 replies to this topic

[aliebrahem17]

What exactly could go wrong in the reboilers if the steam used found LSS steam while in the design it should be LS how ever the desired temperature from the reboiler is achieved

Edited by aliebrahem17, 07 July 2025 - 01:50 AM.

[Pilesar]

The pressure and temperature should not exceed the allowable parameters for equipment and piping. Loss of containment could result which would be undesirable.

[breizh]

Hi,

Regarding heat transfer make sure the steam is not overheated.

Regarding design your equipment is probably not designed for this change (mechanical failure and safety risk could be the consequences)

Breizh

Attached Files

•  Understanding Reboiler Heat Flux Limitations_CCTI_2010.pdf   465.13KB   36 downloads

[katmar]

There are two separate considerations.  These are the mechanical and heat transfer aspects.

 

From a mechanical point of view the high pressure steam may exceed the pressure and temperature rating of the exchanger.  From a heat transfer point of view, putting the steam through a control valve can result in the steam becoming super heated and the heat transfer coefficients for sensible heat transfer are much lower than for condensation.

 

The fact that you have not destroyed your reboiler and the heat duty is being achieved indicates that things are OK, but particularly the mechanical considerations should be checked.

[aliebrahem17]

Sorry for all
I did edit the post there was a mistake
Thanks for all people that replied and I would like to hear your opinion about this problem

[breizh]

Please clarify the acronyms: LSS and LS

Probably good for you to revisit a steam table .

Breizh

[aliebrahem17]

Please clarify the acronyms: LSS and LS
Probably good for you to revisit a steam table .
Breizh

[aliebrahem17]

LSS >>>low pressure super heated steam
LS >>> low pressure saturated steam

[breizh]

Hi,

You need to convert LSS to LS using a desuperheater.

saturated steam offers better heat transfer coefficient .

Superheated steam - Atlas Copco Thailand

Breizh 

Attached Files

•  desuperheater Graham.pdf   561KB   21 downloads
•  desuperheater.pdf   2.36MB   21 downloads

[aliebrahem17]

Well my question is that
What could go wrong to the reboiler if the desuperheater is not working well for much time and the steam goint to the reboiler is LSS not LS

[EnggExp]

1- Delay in boiling rate
2- Lower process concentration on the reboiler outlet (quality)
3-Load increase on the downstream system and if recycling to primary process it will limit the system throughput
4- Energy consumption usually goes up if you have to further purify the reboiler outlet stream. There is a fine balance either you get restricted by system performance and lower the plant rates to compensate for poor heat transfer in your reboiler. Looking at big picture every system interacts with each other.
5- localized overheating can result in mechanical strain
6- lastly condensing steam provides density differential and if you loose that the flow circulation impedes and I am afraid things can get quite ugly process safety wise.