Evaporation technology

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Falling film evaporators

Our falling film evaporators are universally applicable and especially suitable for vapour re-compression.

The most important features at a glance:

  • excellent heat transfer
  • short holding time
  • no overheating
  • minimal operating content
  • compact construction
  • heating surfaces up to 5,000 m²
  • product side minimal pressure drop

Falling film evaporators with mechanical vapour re-compression

Compressors of various types are used for mechanical vapour re-compression.
In addition to the commonly used axial fans, piston, screw, roots and axial compressors are used. Some types only need the heating steam to start up.
During operation, vaporisation energy is completely supplied via the compressor motor as an electric current.

Falling film evaporator with thermal vapour re-compression

The vapours are compressed with the help of a Venturi steam jet compressor. The compressors are designed for constant operating conditions and their efficiency drops sharply in partial load operation.

  • Simple construction without moving parts, therefore very robust and reliable
  • Steam savings 30 to 50% depending on operating ratio

Multi-stage falling film evaporator

The evaporation of water comes with a very high specific energy consumption. This is significantly higher than that for the evaporation of solvents.

Multi-stage evaporators are one way to reduce this energy consumption; the vapours exiting the first evaporator are used to heat the second evaporator, the vapours from the second are used to heat the third and so on.

The system’s energy requirement thus decreases with each additional evaporator stage, however the investment costs are correspondingly higher.

Natural circulation evaporator

Thanks to its simple design, this evaporator is extremely robust and reliable.

It uses the thermo siphon principle and therefore generally works without a circulation pump. Only for liquids with difficult conditions, such as solids content, crystallization or increased viscosity, must successful circulation be supported with a pump; usually with a pipe arc propeller pump.

Typical applications:

  • Evaporation of clean liquids with normal viscosity
  • Sump evaporator for rectification columns

Natural circulation evaporators can alternatively be used in conjunction with a circulation pump as evaporation crystallisers.

Forced circulation evaporator

In contrast to natural circulation, the evaporation does not take place in the heat exchanger tube here, but only when it enters and relaxes in the downstream separator. The product is circulated the heat exchanger by means of a pump. The latter is operated on the product side with slight overpressure, for example by connecting an orifice, so that the liquid flow is heated only by a few degrees without evaporating.

Typical applications:

  • Evaporation of soiled, crust-prone liquids
  • Evaporation of viscous products