4 replies to this topic

[B-2 Spirit]

Hello all,

I am needed to perform adequacy checks for a tray distillation column. The new operation will result in lower vapor loads as the feed is heavier in nature, so I wish to check adequacy during turndown.

I have used KG tower but, it gives only one paramter that is Turndown% which is equivament to % of valves to be open during turndown mode.

Is there any other software that examines the turndown and gives result in more detalied way, such as Downcomer sealing etc...

Thansk for your help in advance....

alok

[aransari85]

Hi Alok,

I have seen in KG tower result details about weeping check is not in much details.

I am using sultech package for hydraulics(Internal version of sulzer).

For customer version there is sulcol package available on Sulzer site, below is the link:

http://www.sulzerche...aspx/tabid-199/

For this you have to apply for it, sulcol have more details than KG tower, it show VSF/VSFmin which should above certail value to avoid weeping at low rates..

Apart from this you can check manually also:

At low vapor rate there will be liquid passing through holes. Hole area to be selected such that vapor velocity at lower operating point will be above the weep point.

Minimum vapor velocity is given by:

uh=(K2 - 0.9(25.4-dh))/(DenV)^0.5

K2 is contant depends on depth of clear liquid on plate. Find attached graph..
which will be hw-hight of weir + how hight over wier.

how = 750 *(Lw/(denL*lw))^(2/3)

Lw-Liquid flow rate(kg/sec)

lw-wier length (m)

how- wier crest (hight above wier) mm

for even flow of liquid over plate how should be atleast 10mm

Vapor velocity through the hole should be higher than uh to avoid weeping..

I hope this will be helpful...

Regards,
Abdul Rashid

Attached Files

•  K2-factor.JPG   20.03KB   38 downloads

[B-2 Spirit]

thanks bro.

have applied for sulcol but no reply, however, i will definitely chk for your manual calculations.

thanks again

[B-2 Spirit]

Hello Abdul,

I noticed that the formulae you gave applicable for sieve trays, I am handling moveable valves. Do we have any correlations for checking weeping in moveable valve trays.

regards,
Alok

[adilameen90]

There is no weeping in the moveable valve trays.