KETTLE REBOILER WEIR 1

[roker]

HELLO,
CAN A KETTLE REBOILER OPERATE WITH NO WEIR, HOW OPERATION WILL BE AFFECTED?

REGARDS,
ROKER

 

[Montemayor]

Yes, it is possible to design a kettle reboiler application without the use of a conventional internal weir (used to ensure that the reboiler tube bundle s 100% submerged in tower bottoms fluid). There are various ways to do this:
[ol 1]
Simply use an overflow pipe nozzle located on the shell-side of the reboiler, at a height that is above the top of the reboiler tube bundle; this method is used quite a lot in TEG dehydration reboilers where the overflow “lean” TEG is distributed to a small, vertical packed bed where the hot lean TEG is sparged with dry stripping natural gas.
[/ol]
[ol 1]
Simply rely on shell-mounted level controller that operates to maintain the level over the tube bundle; this can be a risky operation if the level controller – or the control valve – fails to operate correctly.
[/ol]
[ol 1]
Locate the reboiler at a position relative to the tower it is servicing such that the level control instrumentation on the sump of the tower controls the level of both the tower sump and the reboiler – since both are interconnected. This system is similar in concept to the case where the tube bundle is simply inserted into the side of the tower’s sump and reboils the sump of the tower while it is kept submerged by the tower’s sump level control.
[/ol]
There may be other methods, but the above are the ones that come directly to mind.

 

[25362]

As regards to effects on operation, sometimes the weir is used to create a "quiet" section. The section past the over-flow weir is determined by how much residence time you require or need in that part of the reboiler. Sometimes you may want storage space there to ensure vapor disengagement or to obtain a froth-free liquid, thus avoiding a problematic two-phase overflowing fluid.
Depending on the foaming tendency of the liquid, f.i., low molecular weight hydrocarbons need less seconds (of residence time)than amines and glycols.
Again, it all depends on your needs, scope of work, or requirements.
You also may have a liquid level height to consider if you have a minimum static head of liquid in this section.