The Intermediate Fluid Heat Exchanger has to deal with temperatures from -99,9°C to +10°C by water of 20°C. To prevent water from freezing, the intermediate fluid propylene was used. This TEMA Type Heat Exchanger should be able to operate without a pump.
The company considered several options; an Intermediate Fluid Heat Exchanger with one shell and two bundles, as well as a solution with multiple (up to three) individual Shell & Tube Heat Exchangers.
To determine the best solution wasn’t easy; they had to find out if it could operate without a pump in the propylene circuit, they had to investigate how the equipment could be controlled and they had to find a reliable supplier.
Bronswerk Heat Transfer has many references in the design, construction and delivery of cryogenic equipment, including Intermediate Fluid Heat Exchangers. Although the company involved us in the project at a later stage than our competitors, we managed to create an accepted design, even before one of the competitors could come up with an acceptable solution.
Our proposed solution was better in many ways - simpler, lighter, less costly, and easier to control - than what the customer asked for. We could even offer a solution without intermediate fluid, although they didn’t choose that option they since the end customer decided in an earlier phase that they wanted to proceed with an intermediate fluid solution.
For this reason, we followed the original request and proposed an Intermediate Fluid Vaporizer with two bundles in one shell.
We provided two separate solutions:
- An Intermediate Fluid Heat Exchanger with two bundles in one shell. This was the most optimized solution according to the customer’s initial request. Bronswerk Heat Transfer was the only company that could present an acceptable, reliable solution in the bidding phase.
- A Shell & Tube Heat Exchanger without intermediate fluid, instead there is ethylene on the tube side and water on the shell side. By optimizing the design, we were able to calculate the growth of ice on the tubes. The ice layer acts as a fouling layer; this extra layer is taken into account in the thermal design. The design is made in such a way that the ice layer does not become so thick that the pressure drop on the water side becomes too large or even blocks the flow.
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