Plate fin heat exchanger

A plate-fin heat exchanger is a type of heat exchanger design that uses plates and finned chambers to transfer heat between fluids. It is often categorized as a compact heat exchanger to emphasise its relatively high heat transfer surface area to volume ratio.The plate-fin heat exchanger is widely used in many industries, including the aerospace industry for its compact size and lightweight properties, as well as in cryogenics where its ability to facilitate heat transfer with small temperature differences is utilized. [ cite book|author=Taborek, J., Hewitt, G.F. and Afgan, N.|title=Heat Exchangers: Theory and Practice|publisher=Hemisphere Publishing Corporation|year=1983|id=ISBN 0-07-062806-8]

History

Design of plate-fin heat exchangers

A plate-fin heat exchanger is comprised of layers of corrugated sheets separated by flat metal plates, typically aluminium, to create a series of finned chambers. Separate hot and cold fluid streams flow through alternating layers of the heat exchanger and are enclosed at the edges by side bars. Heat is transferred from one stream through the fin interface to the separator plate and through the next set of fins into the adjacent fluid. The fins also serve to increase the structural integrity of the heat exchanger and allow it to withstand high pressures while providing an extended surface area for heat transfer.

A high degree of flexibility is present in plate-fin heat exchanger design as they can operate with any combination of gas, liquid, and two-phase fluids. [ [http://www.lytron.com/heat_exchangers/custom/heat_exchangers_plate-fin.aspx Lytron Total Thermal Solutions] ] Heat transfer between multiple process streams is also accommodated, [ [http://www.alpema.org/StandardsLeaflet.pdf The Standards of the Brazed Aluminium Plate-Fin Heat Exchanger Manufacturers' Association] ] with a variety of fin heights and types as well as different entry and exit points available for each stream.

The main four type of fins are: "plain", which refer to simple straight-finned triangular or rectangular designs; "herringbone", where the fins are placed sideways to provide a zig-zag path; and "serrated" and "perforated" which refer to cuts and perforations in the fins to augment flow distribution and improve heat transfer.

A disadvantage of plate-fin heat exchangers is that they are prone to fouling due to their small flow channels. They also cannot be mechanically cleaned and require other cleaning procedures and proper filtration for operation with potentially-fouling streams.

The cost of plate-fin heat exchangers is also generally higher than conventional heat exchangers due to a higher level of detail required during manufacture.

Flow arrangement

Layout

Stacking

Cost

Areas of application

Plate-fin heat exchangers have a wide range of applications that include:

* Natural gas liquefaction
* Cryogenic air separation
* Ammonia production
* Offshore processing
* Nuclear engineering
* Syngas production

ee also

*Plate heat exchanger
*Shell and tube heat exchanger
*Heat transfer
*LMTD

References

Coulson, J. and Richardson, J (1999). Chemical Engineering- Fluid Flow. Heat Transfer and Mass Transfer- Volume 1; Reed Educational & Professional Publishing LTD