Shell & Tube VS Plate type Heat Exchanger 6

[Eduard47]

I don't have much experience on plate type heat exhanger. Other than it could be upgraded easily by adding plates, could anybody around have any working knowledge on its "main advantage" compared to the shell and tube heat exchanger? Maybe worth mentioning are cooling and heating effciency as one of the selection criteria, which I don't have reference document for comparison. Thanks

Eduard47

 

[abeltio]

Advantages depend on the application, pressure+temperature are big limitations for the plate type HE's.
Plate type HE's are the choice where complete disassembly is required for cleaning purposes (e.g. food industry).
Plate type HE's are definitely more efficient than shell and tube.
Shell & Tube HE's are the choice for most of the process industries (oil and gas, chemical, etc).
This is just a very basic approach.
Hope this helps.
a.

 

[Eduard47]

Thanks Abeltio, this really helps to keep me starting. With efficiency higher than shell and tube I'm wondering why else should somebody choose a shell and tube if cost really does not matter in the highend (economic calculation?-still don't have the feasibility study). Upgradability and high efficiency seems to be a big deal for me. Thanks again for a good tip.

Eduard

 

[senno]

As mention by abeltio eventhough the plate and frame exchanger have a better eficiency but the have limitation for high pressure and high presssure drop across the system.
rgrds

senno

 

[ralphsare]

we've got about 48 units of titanium PHE (other calls it plate and frame) supplied by APV and another 24 units of SS PHE from Alfa Laval. Maintenance is easy, and perfromance is exellent (only 2 plate failures in 17 years). Increase duty by adding plate is a breeze. Regasketting cost however is a killer.

Both APV and ALfa Laval has produced an exellent catalog with lots of info and illustration. Search the web and request for a copy. If your lucky, they may even conduct a free presentation (lasted for 2 hours, snacks on them).

 

[mark009]

One reason not to use a plate & frame is fire case. If there is a fire the gaskets will melt and process fluid containment will be lost.

 

[MJCronin]

Eddie47,

What no one is mentioning here is the thermal advantage that PHEs have over the ancient "shell & tube" units for certain types of duty.

When the approach temperature is very low, a PHE is a clear choice based on cost and performance. To size a shell & tube heat exhanger (STE) for this kind of duty, the exchanger becomes very large, costly or multiple shells must be used.

There is a penalty for PHEs in terms of pressure drop. Most STEs have a lower pressure drop (and pumping cost savings) for an equivalent thermal duty. This increased cost for pumping power (larger pump motors, more power demanded) can outweigh the cost savings of a cheaper PHE.

A third item to consider is fouling and clogging. Most SHEs can be pulled apart and cleaned cheaper than a PHE. Gaskets are cheaper also....

My opinion only !!!

MJC

 

[ralphsare]

more on phe maintenance and operation.
phe limit is the pressure since plate are thin and cover wide area.
For maintenance, shell and tube would normally require a hydro extractor to pullout if its going to be repaired or hydro jetted plus the added cost of blind and deblind (more opening than phe). Phe , work would entail only loosening the tie bar, slide the pressure plate and reppalce. chemical cleaning is breeze - only two CO noozle needs to be workout. Regasketting is a big time. for a fairly large phe, it cost us around $150,000 an amount that can buy u new s&t. Space (say u need 2 banks of exchanger)and ability to increase duty on the fly is one of its strong point.