Comparison Between a Shell & Tube Evaporator and
a Plate-Type Distiller
  • Shell & tube evaporators and plate-type distillers have comparable upfront capital costs.


  • With a shell & tube evaporator, the tube bundle is one complete assembly, structurally sound, and easy to remove for inspection and/or cleaning with low risk of damage.  A plate-type exhchanger is composed of many thin plates separated by gaskets, making disassembly extremely difficult without damaging the plates.


  • A tube bundle can be easily reinstalled into a unit with only two gaskets needing replacement.  This is in stark contrast to a plate pack which requires the insertion of many thin, delicate gaskets and a careful realignment of the entire plate assembly, making the process impractical to perform in the field.

  • With a shell & tube evaporator, the heat transfer surfaces are uniformly exposed to the turbulent boiling feed water, helping to eliminate dead spots on the heat exchanger surfaces and discouraging scale formation.  With a plate-type distiller, feed water flows diagonally across the plate.  This creates dead spots in opposing corners and leads to scaling.  These spots are hard to clean and lead to long term loss of heat transfer efficiency.


  • Replacement costs for shell & tube equipment amounts to 10% of the original equipment cost, reducing long-term maintenance costs.  In a plate-type distiller, the heat exchanger and boiling chamber are all in one.  Replacement costs equal 90% of the original cost, dramatically increasing long-term maintenance costs.
**This photo is a diagram of a disassembled plate pack.  The red and blue diagonals show the
movement of the feed water.



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