3 replies to this topic

[Ingsalati]

Dear All,

I have two different question regarding the packed column design. The first one is what are the correct system factor and flooding limit for packed column, in particular for Amine Absorber, Amine Stripper and SWS Stripper? For example packed Amine Absorbers shall be designed with 0.8 as system factor and 80% of flooding or with 1 as system factor and 60% of flooding seeing the fact that system factor is a concept related only to tryed column? The second question is using KG Tower to design packed column, what kind of flooding limit shall be selected for Amine Absorber? Costant L/V ratio or Constant Liquid Rate?

Thank you in advance

[Zauberberg]

% of flooding is not related to any system in particular, it is a design parameter that you set based on maximum expected column throughput - and finally deciding how far you want to be from the theoretical point of flooding. For example, 80% flooding means the same for Amine absorber, SWSU stripper, or CDU tower - it means that you don't want to exceed 80% of calculated tower internals capacity at the maximum specified column throughput.

System factor gives you another mandatory information how far your system is from an ideal, non-foaming system. For example, if you specify the SWSU stripper as SF=1 and % flooding 80%, you may expect flooding at design throughput since the actual SF is less than 1 and in the real operation your % flooding will exceed 80%, with a possibility to reach flooding limit, due to higher residence time of liquid phase inside the column. Choosing both the SF and % of flooding is critical in distillation/absorption tower design.

Whatever you select for your tower, it has to come down to the point where you closely work with the vendors - and they will provide you with the optimum design and process guarantees. As long as you work at the conceptual stage, following the rules of thumb will give you decent results.

[Padmakar Katre]

Dear,
I will suggest the readings from the books like,
1.How Equipment works by N. Lieberman and
2.Distillation Design by H. Kister

Probably you will find much more information in detail for your doubts.What is the significance of the system factor and flooding limits in case of column designs is explained in Kister's books on distillation. Hope these readings helps you.

[fra.telli]

Dear All,

I have two different question regarding the packed column design. The first one is what are the correct system factor and flooding limit for packed column, in particular for Amine Absorber, Amine Stripper and SWS Stripper? For example packed Amine Absorbers shall be designed with 0.8 as system factor and 80% of flooding or with 1 as system factor and 60% of flooding seeing the fact that system factor is a concept related only to tryed column? The second question is using KG Tower to design packed column, what kind of flooding limit shall be selected for Amine Absorber? Costant L/V ratio or Constant Liquid Rate?

Thank you in advance

Ciao Ingsalati.

As far as I can remember, KG suggested to move towards 0.8 & 75% for basic design stage; and to.... undisclosed values for detailed design.

Please consider that inside SF value you can have multiple "voices singing together". For ex., you could even decide to consider a lower SF accordingly to uncertainty related to process un-homogeneity or mixing difficulties encreasing with concentration (in adsorption), OR temperature changings, or whatever make sense (and even not sometimes)... you can find lots of reasons - not mentioning side reactions for anti foaming solutions, anticorrosive agents, liquid solution pollutants (metals ions, stain particles...)
In facts, this is the last disuniformity factor that gives you a certain margin of "magic" during design stage that takes in consideration "industrial reality".

Returnig to clarity: reliable vendors will work with you to focus on a tailored process solution. It's their (main) work, maybe it's worth to rely on them... and remember to ask them for documentation and/or litterature (someone is really willing to provide copies)!