Dehumidifying with a salt solution
The Tema Process air dehumidifiers have been developed for cooling, dehumidification and microbiological decontamination of industrial process air. These reliable systems ensure a constant humidity and constant air temperature throughout the year, regardless of outside air conditions or fluctuations in the indoor climate. Dehumidification as low as 15% relative humidity can be reached at low temperatures (-20 to +40°C).
The Tema Process dehumidifier is using a Lithium Chloride salt solution as absorbent. Lithium Chloride is a very strong salt and has an equilibrium curve which closely follows the relative humidity curve of air. The process air will enter the countercurrent dehumidifier and will be dehumidified or humidified in order to maintain this equilibrium. In other words the sprayed salt concentration will control the outlet air relative humidity. By cooling the salt solution before spraying we are able to cool down the air temperature. In this way air temperature and air humidity are both controlled in the same system but can be adjusted independently.
As moisture is continuously absorbed by the salt solution inside the dehumidifier, it becomes diluted and slowly loses drying capacity. To evaporate this surplus of moisture the absorbent is pumped to the regenerator unit. Here the process is turned around, so by heating up the salt solution, moisture is released to an outside air stream and exhausted. The salt solution is continuously pumped between the units in order to provide precise conditions to the process.
Lithium Chloride is a chemically stable, non-toxic, non-vaporizing salt solution which acts as a biocide to mold, bacteria and micro-organisms. Beyond its physical desiccant nature Lithium Chloride is also an effective antifreeze.