Deliquescent dryers are simply large pressure vessels filled with a chemical having an affinity for water. The chemical most commonly used are salt, urea, and calcium chloride. As the compressed air passes through the vessel, the salt dissolves in the water vapor and drips to the bottom of the tank where it is drained. The dried air is then discharged through the outlet port at the same temperature at which it entered. These are also called Deli dryers.
Deliquescent dryers reduce the dew point of the air 15° to 25° F below the inlet air temperature. If the incoming air has a dew point of 90° F, it will leave a deliquescent dryer with a dew point of about 65° F. Depending on operating conditions, some deliquescent dryers can produce dew points as low as -40° F; new deliquescent chemicals may produce even lower dew points.
The operating cost of deliquescent air dryers varies depending on the volume of air flowing through the dryer and the saturation level of the incoming air. Most deli dryers have a sight glass on the side of the dryer through which the desiccant material can be monitored. The dryer is painted with polyurethane epoxy paint to protect it from brine solution formed by drying process.
Deliquescent air dryers have lower cost and are simple in operation. For efficient working salt should be replenished regularly. They can be installed in virtually any location indoors or out, remote locations, mobile equipment or offshore. They consume no energy and have no moving parts.
Applications of Deliquescent Dryer
- Portable blasting and coatings
- Cement plants
- Plant air
- Point-of-use applications
- Dust collectors