Liquid hold up for condenser 1

[kimdelfield]

hi

Has anyone used HTRI to design a shell and tube condenser (U tube) )to include additonal area for condensation/liquid hold up.

any tips

thanks

 

[Montemayor]

kimdelfield:

I've used HTRI and I've used it for their U-tube design program. I've also used it for a cooler- condenser application. What you haven't told us is that besides the simple liquid "hold up", you also intend to subcool that same liquid? If so, then what is done is you dedicate a portion (the last physical bottom part of the shell side) to furnish the sensible heat to the condensate. This is done physically by creating a "dam" that keeps a part of the lower tubes submerged in the liquid. The dam is often achieved externally by configuring the outlet liquid product line in the shape of a "goose neck.

You don't state it, but the condensation must take place in the shell side - never the tube side. You can also condense in the tube side (I have), but it's a special case and very difficult to achieve any subcooling. A pure simple liquid hold up is obtained using a simple "boot" design - on either side - if hold up is all you want.

If you have critical specifications on the degree of subcooling required and need to control it to close tolerances, I would not employ a U-tube design.

 

[kimdelfield]

here is a diagram
_________________________________ top of shell

-------------------------------------.
U tube bundle
-------------------------------------
*
* Hold up for condensation
*
*_________________________________ bottom of shell


How do you simulate the additional extra for hold up area in HTRI. Say I wanted around 20” after the U bundle…….where do I enter it in HTRI

My tube outltet is an inverted kettle reboiler tube layout. It is basically a condenser and a reflux drum rolled into one piece and I am trying to properly simulate this in HTRI.

Height under the nozzle doesn’t work

thanks

 

[Montemayor]

kimdelfield:

OK, now that the rest of the story comes out I can clearly see what you are up against.

You want to use the condenser shell proper as the storage space for liquid hold up. For this, you are using a basic BKU TEMA type kettle configuration with the long shell side at the top - this resembles a vessel called a "guppy", with a lower belly. There is no subcooling taking place - just pure condensing (latent heat transfer).

I wouldn't do it this way; I believe this is an expensive way to obtain liquid hold up - but if that's the way you want to go, fine.

HTRI has nothing to say or to take into consideration with your configuration because the extra volume (not "area") has nothing whatsoever to do with the required heat transfer. What you have is a mechanical configuration and HTRI will calculate the correct heat transfer area for condensation as long as you furnish the proper baffles and/or internals to direct the vapor across the length of the tube bundle. I know how I would install the baffles and liquid drain off from each baffle pass but it near to impossible to draw a necessary sketch in this forum. The best I can do is a written explanation:

Install a horizontal rail system to allow tube bundle insertion and support. Around this rail system install metal plating to form a pseudo-shell wall around the underside of the bundle. This horizontal, rolled plate should have pipe downcomers allowing condensate to drain down into the belly of the guppy. The tube bundle would have the customary baffles to guide the vapors the length of the bundle. This would follow the accepted heat transfer algorithm used by HTRI and therefore allow for its calculation of required heat transfer area.

The way I would do it is to use conventional, less-expensire hardware like a TEMA BEU exchanger with a "double barrel" underneath it. This configuration is a horizontal tank (sometimes a large pipe with ellipsoidal heads on the end) supported under the exchanger and connected to it by dip pipes that lead the formed condensate down into the lower vessel - giving you the hold up required and allowing you to employ a low-cost U-tube design with liquid hold up.

I hope this helps out.

 

[pennpoint]

kimdelfield
My view of what "Montemayor" just posted is, design for a receiver. OK!



Best regards
pennpoint

 

[kimdelfield]

thanks everyone