PRINTED CIRCUIT HEAT EXCHANGER (PCHE)

[takiyasamsama]

Greetings,

Anyone had any experience operating and designing printed circuit heat exchanger (PCHE). From my understanding this kind of exchanger has the best overall heat transfer coefficient in comparison to other kind of heat exchangers and is the best gas-gas heat exchanger on the market today.

Anyone with experience in operation of these kind please tell us what is your feedback of this exchanger. In terms of maintenance, how well does this exchanger compares to regular shell and tube as well and plate and frame. Since the overall heat transfer is high then the amount of surface area for this unit is practically smaller thus the equipment footprint also is smaller.

The pioneer of PCHE, Heatric, claims that this unit is capable of replacing 3 stacks unit of STHE for gas-gas compression aftercooler by 80% which only requires single unit of PCHE vs 3 stacks unit of STHE.

Please share.

 

[Caloooomi]

They have a very high surface area to size ratio, which is what makes them attractive compared to more traditional heat exchangers. Alfa Laval offer their own PCHE, but you would be better off comparing them to plate type heat exchangers such as brazed aluminium HX or plate fin units in stainless steel (I'm sure SPP has them), as they are compact style heat exchangers with the option of multiple circuits, similar design pressures and similar UA values.

Maintenance... well, you need to consider a strainer upstream of the HX but that's not the end of the world. They have very small channels, so once they foul the block up easily and require cleaning using UHP water jetting.

Depends on what you need them for really. They are great for saving space, but cost an arm and a leg to do so!

 

[moltenmetal]

Benefits: small physical size, possibly low weight, all-welded construction, interesting contact patterns possible which are not possible with exchangers of other designs.

Disadvantages: cost ($$$$) and the impracticality of cleaning

If a brazed or even welded plate type heat exchanger is a feasible option it is almost certain to be cheaper.

 

[georgeverghese]

These are very compact and were once upon a time a favourite option in offshore compression cooling and low temp C3plus extraction applications where space and weight savings are a key advantage. But beware these can only be used in clean fluids service - if you have doubts on process and cooling stream fouling tendency, stay with shell and tube.
Another option is all welded plate heat exchangers with wider plate spacings, which would be a better choice if you need some allowance for fouling and cleaning, but these may be limited to ANSI 300lb design pressures (the last time I used these, which is over 10years ago).

 

[takiyasamsama]

From my observation the reason why I believe PCHE is great is because the unique etching method to engrave the fluid channel and as well as the diffusion bonding between plates that makes it by far the unit that can withstand greater operating pressure without experiencing failure on the welded joint like shell and tube.

The downside I see that the ability to cater for fouled services is absolutely disasterous and it's a mandatory to equip with an upstream strainer to filter out any particle more than the fluid channel. Not just that, in fact if your equipment has a tendency to stick to the channel due to temperature change (i.e. sticky fluid or wax like) then it's no use. But I gotta give it to PCHE for its ability to cater for gas-gas application.

On the other side, its rival, PSHE (plate and shell heat exchanger) is practically wipe out most shell and tube and plate and frame heat exchanger application. In Asia, PSHE is slowly picking up and some made its way replacing PCHE as well but the heat transfer coefficient is somewhere between 1500 - 5000 W/m2K depending on application.

I wish to see what other type than can beat out these two PCHE and PSHE.