6 replies to this topic

[jigs1980]

The designer has selected a TEMA BKU type steam reboiler with a two-pass vertical pass partition plate on the tube-side, where steam is used as the heating medium. What is the technical justification for choosing a vertical pass partition plate and does it face operational limitations regarding fluid hydraulics? This specific configuration is highly unconventional for a steam reboiler application. Does this specific configuration induce flow fluctuations or hydraulic oscillations on the tube side?

[Pilesar]

I suggest asking the designer to explain. If the designer takes pride in their work, then will welcome an opportunity to explain how much wisdom was put into the design. Some of my exchanger designs were "unconventional" but I could rarely find anyone who cared enough to try to appreciate them. If this is from an experienced designer, then you may get more explanation than you are ready to receive! If you find the answers unacceptable, then provide the full design for review by a designer you trust. 

[jigs1980]

Does the system operate efficiently or do hydraulic limitations induce steam flow oscillations? The answer to this question, that is exactly what I expected from this forum.

[Pilesar]

A few sentences describing a shell and tube heat exchanger is not a great amount of evidence. I am not smart enough to understand your description with a high degree of confidence. The designer is the person most familiar with the reasons for the design and would be my first resource. If I did not like the answer I received and I had some responsibility for the process, then I would take further action until I were satisfied.

[latexman]

What is the technical justification for choosing a vertical pass partition plate and does it face operational limitations regarding fluid hydraulics? This specific configuration is highly unconventional for a steam reboiler application. Does this specific configuration induce flow fluctuations or hydraulic oscillations on the tube side?

Unless there are severe pipe and fitting limitations in the plant, I see no justification for a vertical pass partition plate. It offers no thermal benefits, only potential problems like uneven condensate drainage, condensate back- up, non-condensable gas trapping, two phase instabilities, condensation-induced water hammer, and maldistribution.

Did you piss off this designer?

[breizh]

Hi,

You may want to talk to these guys.

TEMA U-Tube Types | BEU, AEU, BKU, DEU

 

Kettle reboiler design: A complete guide to efficiency and reliability. - Jazam rejillas

 

 

Note: what said the simulation output for this design? 

 

Breizh

[Pilesar]

Unless there are severe pipe and fitting limitations in the plant, I see no justification for a vertical pass partition plate.

 

One possible reason for horizontal-bend U-tubes in a kettle would be to fit more heat transfer surface area below the liquid level of the shell. The bundle must be completely submerged. A round bundle will have just a few tubes at the top of the bundle so the designer will eliminate them for economy. With a vertical u-tube bend, every tube removed from the top also removes the same number of tubes from the bottom of the bundle. With a horizontal u-tube bend, the shape of the bundle can be flat on the top and round on the bottom. This is just a possibility. The exchanger designer can best explain the reasons for the design.