Closed air drying processes

Closed air drying processes
DryingMate offers design, development and delivery of customized drying systems based on conventional air drying but with 100% recirculation of the drying air.

Benefits of 100% recirculation

  1. No pollution of the local environment with dust or odor
  2. Better process control
  3. Consistent product quality
  4. Reduced energy costs (potentially)
  5. Exploitation of valuable condensate

For drying systems with 100% recirculation of the drying air, the air must be dehumidified. It can be done in two ways:

  1. Using sorptiontechnology or
  2. By cooling the air below the dew point (typically with a heat pump)

Sorptiontechnology
DryingMate offers drying systems with 100% recirculation where dehumidification is done by exploiting standard sorptionaggregate.

The specific energy consumption of these solutions lies in the range 0.9 to 1.4 MWh / ton of water, which corresponds to standard open or semi-open drying processes and the energy can be supplied by electricity, gas, oil or other sources.

The solution can be used in drying processes, wiht drying temperatures in the range of about -20 ° C to about 100 ° C.

See the diagram below of the sorptionprinciple sketched in a Mollierdiagram:

Sorption diagram_1

DryingMate cooperates with COTES A/S on new energy-optimized solutions for dehumidification of air from drying processes using sorptiontechnology.

Heat Pump Technology
For drying processes with drying temperatures below approx. 150 ° C and high water content in the exhaust air, it is worthwhile to analyze the economics of a heat pump solution for dehumidification and heating the drying air.

The heat pump is typically integrated in the drying process so that the heat pump evaporator (cooling coil) cools the exhaust air whereby the water is condensed and can be discharged. The cooled air is directed to the heat pump condenser (heating coil) that heats the air to the desired drying temperature and where the relative humidity is reduced.

The advantage of the heat pump solution compared to the sorptionsolution is that the energy cost under the right conditions is very low. In order for a heat pump solution to be competitive in energy costs, the specific energy consumption should typically be lower than 0.5 MWh / ton of water.

See the following diagram of the heat pump principle sketched in a Mollierdiagram:

HP diagram_1

Please contact us for further information or a quote.