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RecoVap Mechanical Vapor Recompression (MVR) evaporators

Utilizing proven lamella-type heating surfaces for all applications

The challenge

Processing liquor or effluents with minimum energy consumption and maximum plant availability while delivering high condensate quality.

The solution

The RecoVap evaporator uses proven lamella-type heating surfaces in a Mechanical Vapor Recompression (MVR) connection to minimize energy usage. Inherently non-foaming, the lamella evaporator is ideally suited for the low dry solids applications of MVR evaporation with capacities from 10 to 200 t/h in a single unit.

Principle of operation

MVR* evaporators operate on a “heat pump” principle. The evaporated water vapor is recompressed with a simple, low speed centrifugal fan or compressor. The fan increases the saturation temperature of the vapour. After the fan, vapor can be used as heating steam in the same unit. The recompressed vapor condenses and releases its latent heat through the heat transfer surface for further evaporation of the effluent.
* An MVR evaporator is also called a Vapor Compression Evaporator (VCE)

Best possible energy efficiency

Compared to multiple-effect evaporators, MVR evaporation results in minimum overall energy consumption.

Inherently non-foaming design

Low vapor velocities inside the evaporator, low shear rates, and less foaming due to free flow falling film construction are advantages of the ANDRITZ design. This is especially important in MVR evaporators, not only to maximize condensate re-use, but also for protection of the compression fan.

Non-plugging design

Uniform liquor distribution on the heating elements and continuous redistribution of the liquor by the dimpled shape of the lamella surface ensure a completely wetted heating surface and eliminate local scaling or over-concentration of liquor.

Cleanest condensates

High efficiency condensate segregation in evaporator ducts and lamellas in combination with integrated stripping of foul condensate fractions produce clean and re-usable water. Separated methanol is recovered in a methanol liquefaction system.


  • Very low specific energy consumption
  • Does not require steam or cooling water
  • No integration to existing evaporators necessary
  • Location can be chosen relatively freely
  • Excellent condensate segregation
  • Easy capacity control
  • Proven in multiple applications from mechanical pulping effluent to black liquor
3D picture of ANDRITZ Mechanical Vapor Recompression (MVR) evaporator

3D picture of ANDRITZ MVR evaporator

ANDRITZ Mechanical Vapor Recompression (MVR) evaporator

ANDRITZ Mechanical Vapor Recompression (MVR) evaporator


ANDRITZ Oy, Finland

Phone: +358 (0)20 450 5555

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Zellstoff Stendal – SPECTRUM 33
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