10 replies to this topic

[guoyinyanliner]

​"When using HYSYS to calculate column internals for either a structured or random packed column, the calculated pressure drop is extremely low and falls below the lower limit. In this scenario, does it significantly impact the separation efficiency? Additionally, what is the appropriate percentage of column diameter to select when operating at the minimum vapor/liquid load

[breizh]

To your question the answer is yes, contact between liquid and Gas is key for the separation.

 

Breizh

Attached Files

•  separation tower design.pdf   1.41MB   10 downloads
•  eckert& lobo .pdf   370.32KB   7 downloads
•  EQUIPMENT_DESIGN_LECTURE_25 mass transfer equipment 3.pdf   1010.5KB   28 downloads

[guoyinyanliner]

To your question the answer is yes, contact between liquid and Gas is key for the separation.

Breizh

 

Thank you, but it doesn't seem to be what I need

[Pilesar]

From your initial post it seems you are trying to determine the percentage of distillation column cross-sectional area to fill with structured or random packing. I suspect your questions are really different from that. Perhaps you might give additional background and information so more people can understand what you are doing and where you want input from this forum. Then those who choose to respond may be less likely to waste their time trying to help you in ways you do not need.

[Bitan729]

To your question the answer is yes, contact between liquid and Gas is key for the separation.

 

Breizh

Sir, which book it is?  (  EQUIPMENT_DESIGN_LECTURE_25 mass transfer equipment 3.pdf )

[breizh]

Hi Bitan,

To answer your question,

Chemical engineering design 

6th edition 

by Ray Sinnot and Gavin Towler

 

Breizh

[guoyinyanliner]

To your question the answer is yes, contact between liquid and Gas is key for the separation.

Breizh

Sir, which book it is? ( EQUIPMENT_DESIGN_LECTURE_25 mass transfer equipment 3.pdf )

What I want to know is: when I select the normal operating load, the column diameter is calculated based on an 80% load capacity; however, when the column operates at a low load—such as only 10% or even lower—how does this affect the separation performance?

[breizh]

Where did you get that the diameter is based on 80% load capacity?

You cannot operate a distillation column at a low capacity like 10%. 

You must stop and restart when the feed stock is sufficient enough to operate the column. This means you need a buffer tank (feed tank).

Stop and go will create off spec products till the equipment is running steady state. 

 

By the way, is it a continuous process or a batch process?

 

Distillation Column Minimum Wetting Rate Calculation Guide – Industrial Monitor Direct

Diapositiva 1

Microsoft Word - ENGINEERING-DESIGN-GUIDELINES-distillation-column-packing-hudraulics-Rev1.2

0005benn

 

EDIT:

It may be an English language issue, the 80% is related to flood velocity: details in the link underneath

 

Distillation Column - 360° Interactive 3D VR Distillation Laboratory

 

 

For low gas flowrate, check for weeping condition and how to mitigate it.

 

FACTORS AFFECTING DISTILLATION COLUMN OPERATION

Good luck.

 

 

Breizh

Attached Files

•  distillation column guyo.xlsx   256.8KB   2 downloads

[latexman]

What I want to know is: when I select the normal operating load, the column diameter is calculated based on an 80% load capacity; however, when the column operates at a low load—such as only 10% or even lower—how does this affect the separation performance?

 

Turndown Ratio = Maximum Capacity (Flow/Vapor Rate) / Minimum Capacity (Flow/Vapor Rate).

 

Random packing has a higher turndown ratio of 5:1 to 10:1, while structured packing typically has a lower turndown ratio of 3:1 to 5:1.

 

The overall column turndown is often limited by the design of the liquid distributor at the top of the bed. Standard orifice distributors may limit turndown to 2:1 or 3:1, whereas specialized designs can achieve higher ranges.

[guoyinyanliner]

Where did you get that the diameter is based on 80% load capacity?
You cannot operate a distillation column at a low capacity like 10%.
You must stop and restart when the feed stock is sufficient enough to operate the column. This means you need a buffer tank (feed tank).
Stop and go will create off spec products till the equipment is running steady state.

By the way, is it a continuous process or a batch process?

Distillation Column Minimum Wetting Rate Calculation Guide – Industrial Monitor Direct
Diapositiva 1
Microsoft Word - ENGINEERING-DESIGN-GUIDELINES-distillation-column-packing-hudraulics-Rev1.2
0005benn

EDIT:
It may be an English language issue, the 80% is related to flood velocity: details in the link underneath

Distillation Column - 360° Interactive 3D VR Distillation Laboratory


For low gas flowrate, check for weeping condition and how to mitigate it.

FACTORS AFFECTING DISTILLATION COLUMN OPERATION
Good luck.


Breizh

It is an absorption column, not a distillation column

[breizh]

All the things related to flooded column is also valid to find the tower diameter of an absorption tower.

See link below:

Packed Tower Absorber Design: Packing Material, Bed Height, Internals

 

I did my part. Good luck.

Breizh