Dry air dryer
Dry air dryer (TLT) are apparatuses that before, during or after production processes (. Eg plastics processing ) to be dried, a hygroscopic Good means of dry air to dry to provide a desired degree of dryness (see also residual moisture to reach). This refers to adsorption dryers ( adsorption ) or dryers with molecular sieves .
Procedure
Air flows through a cell filled with desiccant and thereby achieves the desired degree of dryness . The parameter is the dew point (e.g. –60 ° C). Then the air is passed through the material to be dried ( granulate or powder) in order to dry it. The drying air is (ideally) guided in a closed circuit ( circulating air dryer ). In order to enable continuous operation, two dry cells are operated alternately. The charged cell is thermally regenerated according to the desorption of the drying medium. The change can be time-controlled or electronically controlled depending on the load level (recorded by measurement) . The temperature of the drying air can be adapted to the material to be dried.
An alternative method for drying hygroscopic plastics generates the dry air using expanded compressed air (i.e. not using a drying agent). The key parameters in this process are the compression of the compressed air and the pressure dew point. Is z. B. compressed air, it can absorb less water in the same ratio (compression to 10 bar results in 1/10 of the absolute amount of water). If this air is then cold-dried (at approx. 5 ° C), the dew point drops to below -25 ° C due to the increase in volume during expansion.
Parameters of a TLT
The primary parameters of a dry air dryer include
- the volume flow of the dry air,
- the achievable dew point of the dry air,
- the temperature of the dry air.
Secondary parameters are
- the energy demand,
- the energy efficiency ,
- the cooling water requirement,
- the installation area,
- the need for maintenance .