TEMA Type CEN Exchanger

[ColinPearson]

Hello World: Hope y'all are safe from COVID!
I work in the refinery turnaround industry though I don't usually get involved in estimating jobs. I've been around this stuff for about 15 years and seen plenty happening but my focus is elsewhere so I've got what I think is a fairly dumb question:

I am tweaking my company's job estimation templates for exchangers to include some appropriate to every common TEMA Type such as AES, BES, BEU, etc. I have a single Type CEN exchanger in the work scope I am currently working on. Can someone help me understand how the bundle could be removed? I'm looking a a reference chart of the front/shell/rear components and their corresponding TEMA designations; the "C" type front head says "Channel Integral with Tubesheet and Removable Cover (Removable Tube Bundle Only) ... It looks as though the channel head is removable b/c it shows what appear to be centerlines indicating bolts; this is in contract to the Type "N" front head where the channel and shell are fabricated together. All of that makes sense to me EXCEPT - how could we remove the bundle (especially with the rear head having a fixed tubesheet)? Thank y'all!

 

[Christine74]

I really don't think that CEN is a valid TEMA descriptor, I suspect that it should have been listed as NEN. Either way the "N" at the end indicates that it's a fixed tubesheet unit so the tube bundle is not removable.

Perhaps the manufacturer had a full diameter tubesheet on one end with a flanged channel that bolts to it? If so the CEN descriptor is definitely wrong but they may have used it to differentiate from a conventional NEN where the tubesheets just get welded directly to the shell and to both channels.


-Christine

 

[ColinPearson]

Thank you for the reply. I think that you're correct here; I believe it should be listed as a CEU type. I've heard of these amazing things called drawings, pictures, data sheets, etc ... seems the client doesn't want to come up with any actual info so we've been scratching our heads. Thanks again!

 

[Christine74]

I found an example of what one manufacturer called a "CEN" heat exchanger. It's actually just an NEN exchanger, but they added a flanged connection at one end:

https://www.lcec.com/objects/catalog/product/extras/104286_1.pdf

If it's a CEU exchanger that should be apparent from the drawings/photos as one end of the exchanger will have a flat channel cover and the other end will have a head.


-Christine

 

[ColinPearson]

Agree that the drawing appears to be NEN. Also agree that the appearance clueing us in to what the rear head type would be but alas, we are working on a proposal with next to zero information. We've asked and gotten nothing so I'm trying to cipher out what I can from the scattered clues we do have. Thank you for your replies; they have helped and I appreciate your time.