Technology centre

Our technical centre forms the bridge between idea, concept and implementation. In our state-of-the-art laboratory machines, future processes can be examined, recorded and proven.

All types of liquid-solid substances find the right treatment option with us.

The right choice of dryer

How the influence of the wet material condition affects the choice of dryer type

While the condition of the wet or dry material does not play a fundamental role in the choice of dryer for vacuum chamber dryers in cabinet or channel form, both the condition and the properties of the wet material are decisive for the appropriate choice of dryer for the other types of dryer. The behaviour of the material during the drying process as well as the condition of the finished dry material play a significant role especially in continuous modes of operation, particularly in the final post-drying section.

If an initially liquid wet material is in a liquid or mushy state after complete dewatering, this process, even if it actually constitutes drying, can be considered on the basis of evaporation considerations.

The following considerations therefore focus mainly on situations where the dried material remains externally dry, i.e. more or less solid.

  • Single-roll dryers are mainly used for transferring low-viscosity wet goods into the corresponding dry state.
  • Two-roll dryers are more suitable for medium to thick-bodied and pulpy to pasty wet goods. Especially for the latter, sufficient adhesion of the wet material to the hot rollers is required.
  • If thin-bodied wet goods contain easily separable particles or if supersaturation and deposition of salts is to be expected even at low evaporation, the two-roll dryer is preferred to the single-roll dryer.
  • In the case of thick and stiff-paste wet material, agitator or paddle dryers are preferred if the material disintegrates easily during progressive drying and otherwise does not have any strongly adhesive properties that could lead to incrustation on the heating surfaces.
  • Paddle dryers are used for all paddleable wet materials in moist crumbly, powdery or granular structure.

Testable parameters

  • Feasibility
  • Scalability for future production plants
  • pH value
  • Residual moisture
  • Time processes in the process
  • Analysis of particle sizes
  • Behaviour during drying
  • Changes in the product during the drying process (caramelisation; condensation)
  • Heat generation
  • Determination of the most efficient drying method

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