6 replies to this topic

[saeed.s]

Hi everyone

 

Do you have any experience in design or operation U type-heat exchanger with fouling fluid ( like: vacuum bottom) in tube side ? I am dealing with a project, that owner prefer to use U type insted of floating type heat exchanger. but I am worry about cleaning & maintenance.

 

Thanks in advance

[latexman]

Tube ID?  Shell diameter and length?

[saeed.s]

Tube ID :   We can choose : 1- Tube OD: 19.05 mm ,  Thk : 2.1 mm  

                                            2- Tube OD: 25.4  mm ,   Thk : 2.1 mm 

 

Shell diameter :  24" pipe  Sch40 , OD: 610 mm , ID: 590.94

 

length:  We can choose : 2 HE With  3 meter long   OR   1 HE With 6 meter long 

Edited by saeed.s, 24 June 2021 - 09:02 AM.

[Bobby Strain]

You need to be sure that is really the owner speaking. If it is, give him what he asks, along with a disclaimer. Many times, the owners employee does not speak for the owner. You didn't mention the shellside fluid. A fixed tubesheet design may present an alternative.

 

Bobby

Edited by Bobby Strain, 24 June 2021 - 09:56 AM.

[latexman]

The u-bends can be chemically cleaned.  They can also be mechanically cleaned, with special tools.  IIRC, 3/4" is not too small, but the 1" may make it easier.  I'd run the options by the plant's high pressure water wash vendor in an e-mail with the details given above.  Their reply is your documentation for your disclaimer.

 

Why does the owner want a u-tube?  High tube pressure?  U-tubes cost about 10% more than fixed tube sheet.

[saeed.s]

Thank you all

 

I attached TEMA sheet for u type & floating type. 

 

1- A fixed tube sheet design may present an alternative:  Because of high temperature difference ( also in start up or shut down situation ) & need for cleaning, removable bundle type should be used.

 

2- Why does the owner want a u-tube?: lower cost compare to floating type & shorter time to fabricate.

 

3- In U type, vacuum bottom  placed in tube  because of lower fouling possibility compare to shell side fluid ( bitumen )

 

4- In Floating type, Due to the possibility of  cleaning  tube with water jet, more  fouling fluid ( bitumen) placed in tube. 

 

5- To reach same temperature in two type of heat exchanger, size of floating type ( 26" ) is greater than U type (24") . ( because of lower tube count in floating type)

 

6- In the link below, I found some case studies

 

https://www.wjta.org...be Cleaning.pdf

 

https://www.tubetech...shed-in-5-hours

Attached Files

•  FLOATING.pdf   127.54KB   5 downloads
•  U TYPE.pdf   127.39KB   2 downloads

Edited by saeed.s, 25 June 2021 - 02:33 AM.

[breizh]

Hi,

You may consider this document with  pros and cons.

Hope this is going to help you .

Breizh