Thin-Layer Drying of Fermentation Spent Liquor Using Corn Bran Adsorbent

Abstract

To utilize the spent liquor from yeast fermentation, sorption drying in a thin static layer was proposed in which the corn bran serving as a solid carrier adsorbs the viscid liquor, and wet granules are then dried in a fixed bed by the hot air stream. A parametric study was conducted to investigate the effects of weight ratio, drying air temperature, air velocity, and layer thickness on the drying kinetics. Experimental results show that a low critical moisture content exists in the drying process, so the majority of moisture was removed during the constant drying rate period. Drying air temperature and layer thickness were two important parameters governing the drying process. In addition to expected effects from convective drying of capillary-porous materials, it was found that the conditioning period during which the spent liquor–bran mixture is left for conditioning markedly improves the drying rate. The possible mechanisms leading to this phenomenon were put forward.

Keywords:

• Conditioning time
• Corn bran
• Sorption drying
• Spent liquor
• Thin-layer drying