Practical Applicability of Plate and Frame Heat Exchangers

Plate & frame heat exchangers are used extensively in food and drink processing, pharmaceutical bulk manufacture, and a host of other applications wherever low volume hold-up and high exchange efficacy are required. They are ideally suited where line pressures are relatively modest and the intrinsic value of the product flowing is high. The internals create high turbulence, and thus they are suited to products where high temperature differences between the process and the utility fluid might lead to product deterioration in other designs of exchanger.

Stainless steel is extensively used for their wetted parts, along with various food-grade elastomers.

They have a singular feature over other types that, in the event of a plate or joint failure and no spare parts being readily available, the assembly can be reconfigured with a lower surface area with basic tools thus enabling some operational activity to be resumed.

Depends on what process your applying it to.

In the Dairy Industry, plate heat exchanger are very common for pasteurization of milk (HTST, High Temperature, Short Time).

Also these plate HX can easily be configured to what we call regen. (theres are other descriptions) that we can reclaim the heated pasteurized milk, to preheat the incoming cold milk prior to pasteurization to bring up the heat, thus using less energy.. I have the efficiencies formula, but it is quite simple due to the laws of thermodynamics.

But some of the drawbacks, if your viscosity is high, the delta P on this heat exchanger are not that good i.e. is quite high.

Another draw back is it can be quite maintenance intensive.

Its also very pricey $$$$

Plate and frame heat exchangers have two main advantages over more conventional exchangers namely;

Their size and their efficiency.

The brazed or welded version can tolerate much higher pressures which makes them ideally suited to more demanding applications. Many gas fired heating systems now incorporate such units. Both versions of the plate are used extensively throughout industry and therefore very practical in many real life applications.

The major problem I have personally encountered with these systems is their ability to act as a filter should the levels of contamination be above and beyond what is specified as acceptable by the manufacturer. This is of course an application issue, so therefore in my experience, one of the best ideas in heat transfer.

Thanks very much to those of you who have replied already. Your responses reinforce what I had previously read. It is very helpful and encouraging to hear it from people who have experience.

The most recent possible application of this technology that I have seen proposed is for heat recovery from the moderator of the CANDU reactor for at least partial use in the pre-heat section of the circuit. Does anyone have any specific advice as to whether a Printed Circuit plate and frame heat exchanger might be suitable for this application?

That's a different ball game, on account of the size.

What is the nature of the two fluids, please?

Thanks for trying to help, but unfortunately I can't remember the details myself. This came up when I was judging a student paper presentation competition so I only have the title of the presentation and whatever information stuck in my mind while I was frantically jotting down a few observations that might help in the final adjudication discussion with the other judges. I was quite impressed with the presentation on this topic, but one of the other judges shot it down because he did not believe that their design was viable, based on his opinion that plate and frame exchangers in general are not practical. The students did talk about fouling considerations, and indicated that while it would need to be further evaluated, the relevant streams are very clean, which is why they determined that this solution would likely work. I am not very familiar with the CANDU reactor myself, but I thought that there might be someone on CR4 who would be more familiar with the streams that would be involved in recovering heat from the moderator of this facility.

We used one of these in a power plant for a water/water application. It worked great and was completely maintenance free (at least at the time I left which it was about 15 years old). High efficiency was the need in our case.

For years, I have used double-contact plate freezers for fast freezing slabs of fish and shrimp and found them excellent. These freezers are also used in ice cream industry for block freezing ice cream.

BTW what kind of plate heat exchanger you are looking for? Which industry?

Recently I came across plate freezer cabinets wherein air is continuously blown over the plates round and round to fast freeze the product.

Aluminum brazed plate exchangers are very common in air separation plants for cryogenic gas to gas or gas to liquid service. It gives long maintenance free life for clean fluids. The beauty of it is that heat can be exchanged not only between two fluids but among several fluids. I have experience up to five different fluids in a single plate exchanger working trouble free since over 25 years. I have seen water to water service too, it require cleaning depending on water quality handled.