Review of solid/liquid desiccant in the drying applications and its regeneration methods

Desiccant material has been used in drying applications because of its low energy consumption, among other advantages. Desiccant material can produce hot and dry air that is beneficial for the drying process. The advantages of using desiccant material in a drying system include continuous drying even during off-sunshine hours, increased drying rate due to hot and dry air, more uniform drying, and increased product quality especially for heat-sensitive products. Some problems in desiccant system such as pressure drop in solid desiccant, carry over of liquid desiccant by air stream and low moisture adsorption capacity may be improved by optimization of the design of desiccant system. Numerous researchers have studied the low cost and low regeneration temperature of desiccant material, and the optimization of desiccant application to produce more competitive energy. The use of heat to regenerate desiccant material in a drying system has limitations in energy saving. However the use of low energy or free available energy such as solar energy and waste heat from industrial processes for regeneration of desiccant material will make the system more cost-effective. This paper presents several works on the regenerative method of the desiccant system and its application in the drying system for both solid and liquid desiccant materials.