Immersion Drying of Wheat Using Al-PILC, Zeolite, Clay, and Sand as Particulate Media

Wheat (Triticum durum) was dried by immersion in a particulate medium grain dryer using natural clay, pillared aluminum clay (Al-PILC), zeolite 13X, and sand as particulate medium at different initial bed temperatures and residence times in the dryer. Results showed that zeolite caused the highest grain moisture loss for a given drying time, followed by Al-PILC, natural clay, and, finally, the sand. The drying capacity of the Al-PILC was similar to that of the zeolite. The Al-PILC transferred an amount of heat equivalent to 85-94% of the heat transferred by zeolite and evaporated 83-93% of the moisture removed by zeolite. Results also showed that the zeolite and the Al-PILC had the best heat and mass transfer properties of the four particulate materials used and that the Al-PILC can be used as an alternative of the zeolite in particulate medium immersion grain drying.