Spray tower drying technology is widely used in the food and pharmaceutical industry. Companies using this technology prefer the dry winter climate to the humid summer climate for increased production and quality.

In winter, the water content in the air is lower, creating optimal operating conditions. In summer, wet conditions have a huge impact on production quality, drying time, and overall operating efficiency.

In addition, the constant variation in the humidity level of outdoor air during production, can have a negative impact on product quality. During the atomization process, it is necessary to stabilize all the parameters of the operation, in order to optimize production, and improve efficiency. Desiccant dehumidifiers make this possible.

Process

The moisture from the inlet air is adsorbed by the desiccant rotor. Dry air can be controlled to reach the desired drying level. As the process is exothermic, the temperature increase is dependent on the amount of adsorbed humidity, but can be up to 50°C. This means energy savings for the tower to reach the desired inlet air temperature. In summer, the outside air introduces huge amounts of water into the tower. For example, 85,000 m³/h of air inlet at 25°C and 60%RH account for 1300 kg/h of water.

Fisair manufactures dehumidifiers for the most demanding industrial applications. DFLEX’s standard ranges could dry up to 30,000 m³/h to supply air down to -20°C dew point, but Fisair has also manufactured units up to 70,000 m³/h in airflow and capable of reaching -70°C dew point.

Main advantages

  • Consistent production all year round, unaffected by outside air, eliminating the need for frequent adjustments, as well as avoiding summer stoppages.
  • Constant inlet air quality ensures constant production quality.
  • Less product attached to the wall of the tower, therefore, less cleaning.
  • Lower risk of fungal and bacterial proliferation.

That is why most yeast manufacturers use these systems.

As an installation example, in 2015, we delivered a dehumidification system to the dairy cooperative SPOMLEK in Radzy-Podlaski, for a type F tower and CDI, to dry serum-based products. It comprises 2 separate systems, with two FISAIR DFLEX2900 dehumidifiers in each. Each dehumidifier is also equipped with a regeneration steam heater and heat exchangers to reduce operating costs. The total amount of dry air fed to both towers is 72,000 m³/h. Since installation of this system, the client has been able to work all year round, regardless of weather conditions.

Application references

Some outstanding references:

    • Conesa
    • Nestlé
    • Spomlek

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